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d2d2fb19f7ea3b192247ca2d6995e66229366cec
clang-p2996/llvm/lib/Transforms/IPO/Attributor.cpp
Johannes Doerfert d2d2fb19f7 [Attributor][FIX] Allow dead users of rewritten function 
If we replace a function with a new one because we rewrite the
signature, dead users may still refer to the old version. With this
patch we reuse the code that deals with dead functions, which the old
versions are, to avoid problems.
2020-01-03 10:43:40 -06:00

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//===- Attributor.cpp - Module-wide attribute deduction -------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements an inter procedural pass that deduces and/or propagating
// attributes. This is done in an abstract interpretation style fixpoint
// iteration. See the Attributor.h file comment and the class descriptions in
// that file for more information.
//
//===----------------------------------------------------------------------===//
#include "llvm/Transforms/IPO/Attributor.h"
#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/CaptureTracking.h"
#include "llvm/Analysis/EHPersonalities.h"
#include "llvm/Analysis/GlobalsModRef.h"
#include "llvm/Analysis/Loads.h"
#include "llvm/Analysis/MemoryBuiltins.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/IR/Argument.h"
#include "llvm/IR/Attributes.h"
#include "llvm/IR/CFG.h"
#include "llvm/IR/InstIterator.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/InitializePasses.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/Local.h"
#include <cassert>
using namespace llvm;
#define DEBUG_TYPE "attributor"
STATISTIC(NumFnWithExactDefinition,
"Number of function with exact definitions");
STATISTIC(NumFnWithoutExactDefinition,
"Number of function without exact definitions");
STATISTIC(NumAttributesTimedOut,
"Number of abstract attributes timed out before fixpoint");
STATISTIC(NumAttributesValidFixpoint,
"Number of abstract attributes in a valid fixpoint state");
STATISTIC(NumAttributesManifested,
"Number of abstract attributes manifested in IR");
STATISTIC(NumAttributesFixedDueToRequiredDependences,
"Number of abstract attributes fixed due to required dependences");
// Some helper macros to deal with statistics tracking.
//
// Usage:
// For simple IR attribute tracking overload trackStatistics in the abstract
// attribute and choose the right STATS_DECLTRACK_********* macro,
// e.g.,:
// void trackStatistics() const override {
// STATS_DECLTRACK_ARG_ATTR(returned)
// }
// If there is a single "increment" side one can use the macro
// STATS_DECLTRACK with a custom message. If there are multiple increment
// sides, STATS_DECL and STATS_TRACK can also be used separatly.
//
#define BUILD_STAT_MSG_IR_ATTR(TYPE, NAME) \
("Number of " #TYPE " marked '" #NAME "'")
#define BUILD_STAT_NAME(NAME, TYPE) NumIR##TYPE##_##NAME
#define STATS_DECL_(NAME, MSG) STATISTIC(NAME, MSG);
#define STATS_DECL(NAME, TYPE, MSG) \
STATS_DECL_(BUILD_STAT_NAME(NAME, TYPE), MSG);
#define STATS_TRACK(NAME, TYPE) ++(BUILD_STAT_NAME(NAME, TYPE));
#define STATS_DECLTRACK(NAME, TYPE, MSG) \
{ \
STATS_DECL(NAME, TYPE, MSG) \
STATS_TRACK(NAME, TYPE) \
}
#define STATS_DECLTRACK_ARG_ATTR(NAME) \
STATS_DECLTRACK(NAME, Arguments, BUILD_STAT_MSG_IR_ATTR(arguments, NAME))
#define STATS_DECLTRACK_CSARG_ATTR(NAME) \
STATS_DECLTRACK(NAME, CSArguments, \
BUILD_STAT_MSG_IR_ATTR(call site arguments, NAME))
#define STATS_DECLTRACK_FN_ATTR(NAME) \
STATS_DECLTRACK(NAME, Function, BUILD_STAT_MSG_IR_ATTR(functions, NAME))
#define STATS_DECLTRACK_CS_ATTR(NAME) \
STATS_DECLTRACK(NAME, CS, BUILD_STAT_MSG_IR_ATTR(call site, NAME))
#define STATS_DECLTRACK_FNRET_ATTR(NAME) \
STATS_DECLTRACK(NAME, FunctionReturn, \
BUILD_STAT_MSG_IR_ATTR(function returns, NAME))
#define STATS_DECLTRACK_CSRET_ATTR(NAME) \
STATS_DECLTRACK(NAME, CSReturn, \
BUILD_STAT_MSG_IR_ATTR(call site returns, NAME))
#define STATS_DECLTRACK_FLOATING_ATTR(NAME) \
STATS_DECLTRACK(NAME, Floating, \
("Number of floating values known to be '" #NAME "'"))
// Specialization of the operator<< for abstract attributes subclasses. This
// disambiguates situations where multiple operators are applicable.
namespace llvm {
#define PIPE_OPERATOR(CLASS) \
raw_ostream &operator<<(raw_ostream &OS, const CLASS &AA) { \
return OS << static_cast<const AbstractAttribute &>(AA); \
}
PIPE_OPERATOR(AAIsDead)
PIPE_OPERATOR(AANoUnwind)
PIPE_OPERATOR(AANoSync)
PIPE_OPERATOR(AANoRecurse)
PIPE_OPERATOR(AAWillReturn)
PIPE_OPERATOR(AANoReturn)
PIPE_OPERATOR(AAReturnedValues)
PIPE_OPERATOR(AANonNull)
PIPE_OPERATOR(AANoAlias)
PIPE_OPERATOR(AADereferenceable)
PIPE_OPERATOR(AAAlign)
PIPE_OPERATOR(AANoCapture)
PIPE_OPERATOR(AAValueSimplify)
PIPE_OPERATOR(AANoFree)
PIPE_OPERATOR(AAHeapToStack)
PIPE_OPERATOR(AAReachability)
PIPE_OPERATOR(AAMemoryBehavior)
#undef PIPE_OPERATOR
} // namespace llvm
// TODO: Determine a good default value.
//
// In the LLVM-TS and SPEC2006, 32 seems to not induce compile time overheads
// (when run with the first 5 abstract attributes). The results also indicate
// that we never reach 32 iterations but always find a fixpoint sooner.
//
// This will become more evolved once we perform two interleaved fixpoint
// iterations: bottom-up and top-down.
static cl::opt<unsigned>
MaxFixpointIterations("attributor-max-iterations", cl::Hidden,
cl::desc("Maximal number of fixpoint iterations."),
cl::init(32));
static cl::opt<bool> VerifyMaxFixpointIterations(
"attributor-max-iterations-verify", cl::Hidden,
cl::desc("Verify that max-iterations is a tight bound for a fixpoint"),
cl::init(false));
static cl::opt<bool> DisableAttributor(
"attributor-disable", cl::Hidden,
cl::desc("Disable the attributor inter-procedural deduction pass."),
cl::init(true));
static cl::opt<bool> AnnotateDeclarationCallSites(
"attributor-annotate-decl-cs", cl::Hidden,
cl::desc("Annoate call sites of function declarations."), cl::init(false));
static cl::opt<bool> ManifestInternal(
"attributor-manifest-internal", cl::Hidden,
cl::desc("Manifest Attributor internal string attributes."),
cl::init(false));
static cl::opt<unsigned> DepRecInterval(
"attributor-dependence-recompute-interval", cl::Hidden,
cl::desc("Number of iterations until dependences are recomputed."),
cl::init(4));
static cl::opt<bool> EnableHeapToStack("enable-heap-to-stack-conversion",
cl::init(true), cl::Hidden);
static cl::opt<int> MaxHeapToStackSize("max-heap-to-stack-size", cl::init(128),
cl::Hidden);
/// Logic operators for the change status enum class.
///
///{
ChangeStatus llvm::operator|(ChangeStatus l, ChangeStatus r) {
return l == ChangeStatus::CHANGED ? l : r;
}
ChangeStatus llvm::operator&(ChangeStatus l, ChangeStatus r) {
return l == ChangeStatus::UNCHANGED ? l : r;
}
///}
Argument *IRPosition::getAssociatedArgument() const {
if (getPositionKind() == IRP_ARGUMENT)
return cast<Argument>(&getAnchorValue());
// Not an Argument and no argument number means this is not a call site
// argument, thus we cannot find a callback argument to return.
int ArgNo = getArgNo();
if (ArgNo < 0)
return nullptr;
// Use abstract call sites to make the connection between the call site
// values and the ones in callbacks. If a callback was found that makes use
// of the underlying call site operand, we want the corresponding callback
// callee argument and not the direct callee argument.
Optional<Argument *> CBCandidateArg;
SmallVector<const Use *, 4> CBUses;
ImmutableCallSite ICS(&getAnchorValue());
AbstractCallSite::getCallbackUses(ICS, CBUses);
for (const Use *U : CBUses) {
AbstractCallSite ACS(U);
assert(ACS && ACS.isCallbackCall());
if (!ACS.getCalledFunction())
continue;
for (unsigned u = 0, e = ACS.getNumArgOperands(); u < e; u++) {
// Test if the underlying call site operand is argument number u of the
// callback callee.
if (ACS.getCallArgOperandNo(u) != ArgNo)
continue;
assert(ACS.getCalledFunction()->arg_size() > u &&
"ACS mapped into var-args arguments!");
if (CBCandidateArg.hasValue()) {
CBCandidateArg = nullptr;
break;
}
CBCandidateArg = ACS.getCalledFunction()->getArg(u);
}
}
// If we found a unique callback candidate argument, return it.
if (CBCandidateArg.hasValue() && CBCandidateArg.getValue())
return CBCandidateArg.getValue();
// If no callbacks were found, or none used the underlying call site operand
// exclusively, use the direct callee argument if available.
const Function *Callee = ICS.getCalledFunction();
if (Callee && Callee->arg_size() > unsigned(ArgNo))
return Callee->getArg(ArgNo);
return nullptr;
}
/// For calls (and invokes) we will only replace instruction uses to not disturb
/// the old style call graph.
/// TODO: Remove this once we get rid of the old PM.
static void replaceAllInstructionUsesWith(Value &Old, Value &New) {
if (!isa<CallBase>(Old))
return Old.replaceAllUsesWith(&New);
SmallVector<Use *, 8> Uses;
for (Use &U : Old.uses())
if (isa<Instruction>(U.getUser()))
Uses.push_back(&U);
for (Use *U : Uses)
U->set(&New);
}
/// Recursively visit all values that might become \p IRP at some point. This
/// will be done by looking through cast instructions, selects, phis, and calls
/// with the "returned" attribute. Once we cannot look through the value any
/// further, the callback \p VisitValueCB is invoked and passed the current
/// value, the \p State, and a flag to indicate if we stripped anything. To
/// limit how much effort is invested, we will never visit more values than
/// specified by \p MaxValues.
template <typename AAType, typename StateTy>
static bool genericValueTraversal(
Attributor &A, IRPosition IRP, const AAType &QueryingAA, StateTy &State,
const function_ref<bool(Value &, StateTy &, bool)> &VisitValueCB,
int MaxValues = 8) {
const AAIsDead *LivenessAA = nullptr;
if (IRP.getAnchorScope())
LivenessAA = &A.getAAFor<AAIsDead>(
QueryingAA, IRPosition::function(*IRP.getAnchorScope()),
/* TrackDependence */ false);
bool AnyDead = false;
// TODO: Use Positions here to allow context sensitivity in VisitValueCB
SmallPtrSet<Value *, 16> Visited;
SmallVector<Value *, 16> Worklist;
Worklist.push_back(&IRP.getAssociatedValue());
int Iteration = 0;
do {
Value *V = Worklist.pop_back_val();
// Check if we should process the current value. To prevent endless
// recursion keep a record of the values we followed!
if (!Visited.insert(V).second)
continue;
// Make sure we limit the compile time for complex expressions.
if (Iteration++ >= MaxValues)
return false;
// Explicitly look through calls with a "returned" attribute if we do
// not have a pointer as stripPointerCasts only works on them.
Value *NewV = nullptr;
if (V->getType()->isPointerTy()) {
NewV = V->stripPointerCasts();
} else {
CallSite CS(V);
if (CS && CS.getCalledFunction()) {
for (Argument &Arg : CS.getCalledFunction()->args())
if (Arg.hasReturnedAttr()) {
NewV = CS.getArgOperand(Arg.getArgNo());
break;
}
}
}
if (NewV && NewV != V) {
Worklist.push_back(NewV);
continue;
}
// Look through select instructions, visit both potential values.
if (auto *SI = dyn_cast<SelectInst>(V)) {
Worklist.push_back(SI->getTrueValue());
Worklist.push_back(SI->getFalseValue());
continue;
}
// Look through phi nodes, visit all live operands.
if (auto *PHI = dyn_cast<PHINode>(V)) {
assert(LivenessAA &&
"Expected liveness in the presence of instructions!");
for (unsigned u = 0, e = PHI->getNumIncomingValues(); u < e; u++) {
const BasicBlock *IncomingBB = PHI->getIncomingBlock(u);
if (LivenessAA->isAssumedDead(IncomingBB->getTerminator())) {
AnyDead = true;
continue;
}
Worklist.push_back(PHI->getIncomingValue(u));
}
continue;
}
// Once a leaf is reached we inform the user through the callback.
if (!VisitValueCB(*V, State, Iteration > 1))
return false;
} while (!Worklist.empty());
// If we actually used liveness information so we have to record a dependence.
if (AnyDead)
A.recordDependence(*LivenessAA, QueryingAA, DepClassTy::OPTIONAL);
// All values have been visited.
return true;
}
/// Return true if \p New is equal or worse than \p Old.
static bool isEqualOrWorse(const Attribute &New, const Attribute &Old) {
if (!Old.isIntAttribute())
return true;
return Old.getValueAsInt() >= New.getValueAsInt();
}
/// Return true if the information provided by \p Attr was added to the
/// attribute list \p Attrs. This is only the case if it was not already present
/// in \p Attrs at the position describe by \p PK and \p AttrIdx.
static bool addIfNotExistent(LLVMContext &Ctx, const Attribute &Attr,
AttributeList &Attrs, int AttrIdx) {
if (Attr.isEnumAttribute()) {
Attribute::AttrKind Kind = Attr.getKindAsEnum();
if (Attrs.hasAttribute(AttrIdx, Kind))
if (isEqualOrWorse(Attr, Attrs.getAttribute(AttrIdx, Kind)))
return false;
Attrs = Attrs.addAttribute(Ctx, AttrIdx, Attr);
return true;
}
if (Attr.isStringAttribute()) {
StringRef Kind = Attr.getKindAsString();
if (Attrs.hasAttribute(AttrIdx, Kind))
if (isEqualOrWorse(Attr, Attrs.getAttribute(AttrIdx, Kind)))
return false;
Attrs = Attrs.addAttribute(Ctx, AttrIdx, Attr);
return true;
}
if (Attr.isIntAttribute()) {
Attribute::AttrKind Kind = Attr.getKindAsEnum();
if (Attrs.hasAttribute(AttrIdx, Kind))
if (isEqualOrWorse(Attr, Attrs.getAttribute(AttrIdx, Kind)))
return false;
Attrs = Attrs.removeAttribute(Ctx, AttrIdx, Kind);
Attrs = Attrs.addAttribute(Ctx, AttrIdx, Attr);
return true;
}
llvm_unreachable("Expected enum or string attribute!");
}
static const Value *
getBasePointerOfAccessPointerOperand(const Instruction *I, int64_t &BytesOffset,
const DataLayout &DL,
bool AllowNonInbounds = false) {
const Value *Ptr =
Attributor::getPointerOperand(I, /* AllowVolatile */ false);
if (!Ptr)
return nullptr;
return GetPointerBaseWithConstantOffset(Ptr, BytesOffset, DL,
AllowNonInbounds);
}
ChangeStatus AbstractAttribute::update(Attributor &A) {
ChangeStatus HasChanged = ChangeStatus::UNCHANGED;
if (getState().isAtFixpoint())
return HasChanged;
LLVM_DEBUG(dbgs() << "[Attributor] Update: " << *this << "\n");
HasChanged = updateImpl(A);
LLVM_DEBUG(dbgs() << "[Attributor] Update " << HasChanged << " " << *this
<< "\n");
return HasChanged;
}
ChangeStatus
IRAttributeManifest::manifestAttrs(Attributor &A, const IRPosition &IRP,
const ArrayRef<Attribute> &DeducedAttrs) {
Function *ScopeFn = IRP.getAssociatedFunction();
IRPosition::Kind PK = IRP.getPositionKind();
// In the following some generic code that will manifest attributes in
// DeducedAttrs if they improve the current IR. Due to the different
// annotation positions we use the underlying AttributeList interface.
AttributeList Attrs;
switch (PK) {
case IRPosition::IRP_INVALID:
case IRPosition::IRP_FLOAT:
return ChangeStatus::UNCHANGED;
case IRPosition::IRP_ARGUMENT:
case IRPosition::IRP_FUNCTION:
case IRPosition::IRP_RETURNED:
Attrs = ScopeFn->getAttributes();
break;
case IRPosition::IRP_CALL_SITE:
case IRPosition::IRP_CALL_SITE_RETURNED:
case IRPosition::IRP_CALL_SITE_ARGUMENT:
Attrs = ImmutableCallSite(&IRP.getAnchorValue()).getAttributes();
break;
}
ChangeStatus HasChanged = ChangeStatus::UNCHANGED;
LLVMContext &Ctx = IRP.getAnchorValue().getContext();
for (const Attribute &Attr : DeducedAttrs) {
if (!addIfNotExistent(Ctx, Attr, Attrs, IRP.getAttrIdx()))
continue;
HasChanged = ChangeStatus::CHANGED;
}
if (HasChanged == ChangeStatus::UNCHANGED)
return HasChanged;
switch (PK) {
case IRPosition::IRP_ARGUMENT:
case IRPosition::IRP_FUNCTION:
case IRPosition::IRP_RETURNED:
ScopeFn->setAttributes(Attrs);
break;
case IRPosition::IRP_CALL_SITE:
case IRPosition::IRP_CALL_SITE_RETURNED:
case IRPosition::IRP_CALL_SITE_ARGUMENT:
CallSite(&IRP.getAnchorValue()).setAttributes(Attrs);
break;
case IRPosition::IRP_INVALID:
case IRPosition::IRP_FLOAT:
break;
}
return HasChanged;
}
const IRPosition IRPosition::EmptyKey(255);
const IRPosition IRPosition::TombstoneKey(256);
SubsumingPositionIterator::SubsumingPositionIterator(const IRPosition &IRP) {
IRPositions.emplace_back(IRP);
ImmutableCallSite ICS(&IRP.getAnchorValue());
switch (IRP.getPositionKind()) {
case IRPosition::IRP_INVALID:
case IRPosition::IRP_FLOAT:
case IRPosition::IRP_FUNCTION:
return;
case IRPosition::IRP_ARGUMENT:
case IRPosition::IRP_RETURNED:
IRPositions.emplace_back(
IRPosition::function(*IRP.getAssociatedFunction()));
return;
case IRPosition::IRP_CALL_SITE:
assert(ICS && "Expected call site!");
// TODO: We need to look at the operand bundles similar to the redirection
// in CallBase.
if (!ICS.hasOperandBundles())
if (const Function *Callee = ICS.getCalledFunction())
IRPositions.emplace_back(IRPosition::function(*Callee));
return;
case IRPosition::IRP_CALL_SITE_RETURNED:
assert(ICS && "Expected call site!");
// TODO: We need to look at the operand bundles similar to the redirection
// in CallBase.
if (!ICS.hasOperandBundles()) {
if (const Function *Callee = ICS.getCalledFunction()) {
IRPositions.emplace_back(IRPosition::returned(*Callee));
IRPositions.emplace_back(IRPosition::function(*Callee));
}
}
IRPositions.emplace_back(
IRPosition::callsite_function(cast<CallBase>(*ICS.getInstruction())));
return;
case IRPosition::IRP_CALL_SITE_ARGUMENT: {
int ArgNo = IRP.getArgNo();
assert(ICS && ArgNo >= 0 && "Expected call site!");
// TODO: We need to look at the operand bundles similar to the redirection
// in CallBase.
if (!ICS.hasOperandBundles()) {
const Function *Callee = ICS.getCalledFunction();
if (Callee && Callee->arg_size() > unsigned(ArgNo))
IRPositions.emplace_back(IRPosition::argument(*Callee->getArg(ArgNo)));
if (Callee)
IRPositions.emplace_back(IRPosition::function(*Callee));
}
IRPositions.emplace_back(IRPosition::value(IRP.getAssociatedValue()));
return;
}
}
}
bool IRPosition::hasAttr(ArrayRef<Attribute::AttrKind> AKs,
bool IgnoreSubsumingPositions) const {
for (const IRPosition &EquivIRP : SubsumingPositionIterator(*this)) {
for (Attribute::AttrKind AK : AKs)
if (EquivIRP.getAttr(AK).getKindAsEnum() == AK)
return true;
// The first position returned by the SubsumingPositionIterator is
// always the position itself. If we ignore subsuming positions we
// are done after the first iteration.
if (IgnoreSubsumingPositions)
break;
}
return false;
}
void IRPosition::getAttrs(ArrayRef<Attribute::AttrKind> AKs,
SmallVectorImpl<Attribute> &Attrs,
bool IgnoreSubsumingPositions) const {
for (const IRPosition &EquivIRP : SubsumingPositionIterator(*this)) {
for (Attribute::AttrKind AK : AKs) {
const Attribute &Attr = EquivIRP.getAttr(AK);
if (Attr.getKindAsEnum() == AK)
Attrs.push_back(Attr);
}
// The first position returned by the SubsumingPositionIterator is
// always the position itself. If we ignore subsuming positions we
// are done after the first iteration.
if (IgnoreSubsumingPositions)
break;
}
}
void IRPosition::verify() {
switch (KindOrArgNo) {
default:
assert(KindOrArgNo >= 0 && "Expected argument or call site argument!");
assert((isa<CallBase>(AnchorVal) || isa<Argument>(AnchorVal)) &&
"Expected call base or argument for positive attribute index!");
if (isa<Argument>(AnchorVal)) {
assert(cast<Argument>(AnchorVal)->getArgNo() == unsigned(getArgNo()) &&
"Argument number mismatch!");
assert(cast<Argument>(AnchorVal) == &getAssociatedValue() &&
"Associated value mismatch!");
} else {
assert(cast<CallBase>(*AnchorVal).arg_size() > unsigned(getArgNo()) &&
"Call site argument number mismatch!");
assert(cast<CallBase>(*AnchorVal).getArgOperand(getArgNo()) ==
&getAssociatedValue() &&
"Associated value mismatch!");
}
break;
case IRP_INVALID:
assert(!AnchorVal && "Expected no value for an invalid position!");
break;
case IRP_FLOAT:
assert((!isa<CallBase>(&getAssociatedValue()) &&
!isa<Argument>(&getAssociatedValue())) &&
"Expected specialized kind for call base and argument values!");
break;
case IRP_RETURNED:
assert(isa<Function>(AnchorVal) &&
"Expected function for a 'returned' position!");
assert(AnchorVal == &getAssociatedValue() && "Associated value mismatch!");
break;
case IRP_CALL_SITE_RETURNED:
assert((isa<CallBase>(AnchorVal)) &&
"Expected call base for 'call site returned' position!");
assert(AnchorVal == &getAssociatedValue() && "Associated value mismatch!");
break;
case IRP_CALL_SITE:
assert((isa<CallBase>(AnchorVal)) &&
"Expected call base for 'call site function' position!");
assert(AnchorVal == &getAssociatedValue() && "Associated value mismatch!");
break;
case IRP_FUNCTION:
assert(isa<Function>(AnchorVal) &&
"Expected function for a 'function' position!");
assert(AnchorVal == &getAssociatedValue() && "Associated value mismatch!");
break;
}
}
namespace {
/// Helper function to clamp a state \p S of type \p StateType with the
/// information in \p R and indicate/return if \p S did change (as-in update is
/// required to be run again).
template <typename StateType>
ChangeStatus clampStateAndIndicateChange(StateType &S, const StateType &R) {
auto Assumed = S.getAssumed();
S ^= R;
return Assumed == S.getAssumed() ? ChangeStatus::UNCHANGED
: ChangeStatus::CHANGED;
}
/// Clamp the information known for all returned values of a function
/// (identified by \p QueryingAA) into \p S.
template <typename AAType, typename StateType = typename AAType::StateType>
static void clampReturnedValueStates(Attributor &A, const AAType &QueryingAA,
StateType &S) {
LLVM_DEBUG(dbgs() << "[Attributor] Clamp return value states for "
<< QueryingAA << " into " << S << "\n");
assert((QueryingAA.getIRPosition().getPositionKind() ==
IRPosition::IRP_RETURNED ||
QueryingAA.getIRPosition().getPositionKind() ==
IRPosition::IRP_CALL_SITE_RETURNED) &&
"Can only clamp returned value states for a function returned or call "
"site returned position!");
// Use an optional state as there might not be any return values and we want
// to join (IntegerState::operator&) the state of all there are.
Optional<StateType> T;
// Callback for each possibly returned value.
auto CheckReturnValue = [&](Value &RV) -> bool {
const IRPosition &RVPos = IRPosition::value(RV);
const AAType &AA = A.getAAFor<AAType>(QueryingAA, RVPos);
LLVM_DEBUG(dbgs() << "[Attributor] RV: " << RV << " AA: " << AA.getAsStr()
<< " @ " << RVPos << "\n");
const StateType &AAS = static_cast<const StateType &>(AA.getState());
if (T.hasValue())
*T &= AAS;
else
T = AAS;
LLVM_DEBUG(dbgs() << "[Attributor] AA State: " << AAS << " RV State: " << T
<< "\n");
return T->isValidState();
};
if (!A.checkForAllReturnedValues(CheckReturnValue, QueryingAA))
S.indicatePessimisticFixpoint();
else if (T.hasValue())
S ^= *T;
}
/// Helper class to compose two generic deduction
template <typename AAType, typename Base, typename StateType,
template <typename...> class F, template <typename...> class G>
struct AAComposeTwoGenericDeduction
: public F<AAType, G<AAType, Base, StateType>, StateType> {
AAComposeTwoGenericDeduction(const IRPosition &IRP)
: F<AAType, G<AAType, Base, StateType>, StateType>(IRP) {}
/// See AbstractAttribute::updateImpl(...).
ChangeStatus updateImpl(Attributor &A) override {
ChangeStatus ChangedF =
F<AAType, G<AAType, Base, StateType>, StateType>::updateImpl(A);
ChangeStatus ChangedG = G<AAType, Base, StateType>::updateImpl(A);
return ChangedF | ChangedG;
}
};
/// Helper class for generic deduction: return value -> returned position.
template <typename AAType, typename Base,
typename StateType = typename AAType::StateType>
struct AAReturnedFromReturnedValues : public Base {
AAReturnedFromReturnedValues(const IRPosition &IRP) : Base(IRP) {}
/// See AbstractAttribute::updateImpl(...).
ChangeStatus updateImpl(Attributor &A) override {
StateType S;
clampReturnedValueStates<AAType, StateType>(A, *this, S);
// TODO: If we know we visited all returned values, thus no are assumed
// dead, we can take the known information from the state T.
return clampStateAndIndicateChange<StateType>(this->getState(), S);
}
};
/// Clamp the information known at all call sites for a given argument
/// (identified by \p QueryingAA) into \p S.
template <typename AAType, typename StateType = typename AAType::StateType>
static void clampCallSiteArgumentStates(Attributor &A, const AAType &QueryingAA,
StateType &S) {
LLVM_DEBUG(dbgs() << "[Attributor] Clamp call site argument states for "
<< QueryingAA << " into " << S << "\n");
assert(QueryingAA.getIRPosition().getPositionKind() ==
IRPosition::IRP_ARGUMENT &&
"Can only clamp call site argument states for an argument position!");
// Use an optional state as there might not be any return values and we want
// to join (IntegerState::operator&) the state of all there are.
Optional<StateType> T;
// The argument number which is also the call site argument number.
unsigned ArgNo = QueryingAA.getIRPosition().getArgNo();
auto CallSiteCheck = [&](AbstractCallSite ACS) {
const IRPosition &ACSArgPos = IRPosition::callsite_argument(ACS, ArgNo);
// Check if a coresponding argument was found or if it is on not associated
// (which can happen for callback calls).
if (ACSArgPos.getPositionKind() == IRPosition::IRP_INVALID)
return false;
const AAType &AA = A.getAAFor<AAType>(QueryingAA, ACSArgPos);
LLVM_DEBUG(dbgs() << "[Attributor] ACS: " << *ACS.getInstruction()
<< " AA: " << AA.getAsStr() << " @" << ACSArgPos << "\n");
const StateType &AAS = static_cast<const StateType &>(AA.getState());
if (T.hasValue())
*T &= AAS;
else
T = AAS;
LLVM_DEBUG(dbgs() << "[Attributor] AA State: " << AAS << " CSA State: " << T
<< "\n");
return T->isValidState();
};
if (!A.checkForAllCallSites(CallSiteCheck, QueryingAA, true))
S.indicatePessimisticFixpoint();
else if (T.hasValue())
S ^= *T;
}
/// Helper class for generic deduction: call site argument -> argument position.
template <typename AAType, typename Base,
typename StateType = typename AAType::StateType>
struct AAArgumentFromCallSiteArguments : public Base {
AAArgumentFromCallSiteArguments(const IRPosition &IRP) : Base(IRP) {}
/// See AbstractAttribute::updateImpl(...).
ChangeStatus updateImpl(Attributor &A) override {
StateType S;
clampCallSiteArgumentStates<AAType, StateType>(A, *this, S);
// TODO: If we know we visited all incoming values, thus no are assumed
// dead, we can take the known information from the state T.
return clampStateAndIndicateChange<StateType>(this->getState(), S);
}
};
/// Helper class for generic replication: function returned -> cs returned.
template <typename AAType, typename Base,
typename StateType = typename AAType::StateType>
struct AACallSiteReturnedFromReturned : public Base {
AACallSiteReturnedFromReturned(const IRPosition &IRP) : Base(IRP) {}
/// See AbstractAttribute::updateImpl(...).
ChangeStatus updateImpl(Attributor &A) override {
assert(this->getIRPosition().getPositionKind() ==
IRPosition::IRP_CALL_SITE_RETURNED &&
"Can only wrap function returned positions for call site returned "
"positions!");
auto &S = this->getState();
const Function *AssociatedFunction =
this->getIRPosition().getAssociatedFunction();
if (!AssociatedFunction)
return S.indicatePessimisticFixpoint();
IRPosition FnPos = IRPosition::returned(*AssociatedFunction);
const AAType &AA = A.getAAFor<AAType>(*this, FnPos);
return clampStateAndIndicateChange(
S, static_cast<const typename AAType::StateType &>(AA.getState()));
}
};
/// Helper class for generic deduction using must-be-executed-context
/// Base class is required to have `followUse` method.
/// bool followUse(Attributor &A, const Use *U, const Instruction *I)
/// U - Underlying use.
/// I - The user of the \p U.
/// `followUse` returns true if the value should be tracked transitively.
template <typename AAType, typename Base,
typename StateType = typename AAType::StateType>
struct AAFromMustBeExecutedContext : public Base {
AAFromMustBeExecutedContext(const IRPosition &IRP) : Base(IRP) {}
void initialize(Attributor &A) override {
Base::initialize(A);
const IRPosition &IRP = this->getIRPosition();
Instruction *CtxI = IRP.getCtxI();
if (!CtxI)
return;
for (const Use &U : IRP.getAssociatedValue().uses())
Uses.insert(&U);
}
/// See AbstractAttribute::updateImpl(...).
ChangeStatus updateImpl(Attributor &A) override {
auto BeforeState = this->getState();
auto &S = this->getState();
Instruction *CtxI = this->getIRPosition().getCtxI();
if (!CtxI)
return ChangeStatus::UNCHANGED;
MustBeExecutedContextExplorer &Explorer =
A.getInfoCache().getMustBeExecutedContextExplorer();
auto EIt = Explorer.begin(CtxI), EEnd = Explorer.end(CtxI);
for (unsigned u = 0; u < Uses.size(); ++u) {
const Use *U = Uses[u];
if (const Instruction *UserI = dyn_cast<Instruction>(U->getUser())) {
bool Found = Explorer.findInContextOf(UserI, EIt, EEnd);
if (Found && Base::followUse(A, U, UserI))
for (const Use &Us : UserI->uses())
Uses.insert(&Us);
}
}
return BeforeState == S ? ChangeStatus::UNCHANGED : ChangeStatus::CHANGED;
}
private:
/// Container for (transitive) uses of the associated value.
SetVector<const Use *> Uses;
};
template <typename AAType, typename Base,
typename StateType = typename AAType::StateType>
using AAArgumentFromCallSiteArgumentsAndMustBeExecutedContext =
AAComposeTwoGenericDeduction<AAType, Base, StateType,
AAFromMustBeExecutedContext,
AAArgumentFromCallSiteArguments>;
template <typename AAType, typename Base,
typename StateType = typename AAType::StateType>
using AACallSiteReturnedFromReturnedAndMustBeExecutedContext =
AAComposeTwoGenericDeduction<AAType, Base, StateType,
AAFromMustBeExecutedContext,
AACallSiteReturnedFromReturned>;
/// -----------------------NoUnwind Function Attribute--------------------------
struct AANoUnwindImpl : AANoUnwind {
AANoUnwindImpl(const IRPosition &IRP) : AANoUnwind(IRP) {}
const std::string getAsStr() const override {
return getAssumed() ? "nounwind" : "may-unwind";
}
/// See AbstractAttribute::updateImpl(...).
ChangeStatus updateImpl(Attributor &A) override {
auto Opcodes = {
(unsigned)Instruction::Invoke, (unsigned)Instruction::CallBr,
(unsigned)Instruction::Call, (unsigned)Instruction::CleanupRet,
(unsigned)Instruction::CatchSwitch, (unsigned)Instruction::Resume};
auto CheckForNoUnwind = [&](Instruction &I) {
if (!I.mayThrow())
return true;
if (ImmutableCallSite ICS = ImmutableCallSite(&I)) {
const auto &NoUnwindAA =
A.getAAFor<AANoUnwind>(*this, IRPosition::callsite_function(ICS));
return NoUnwindAA.isAssumedNoUnwind();
}
return false;
};
if (!A.checkForAllInstructions(CheckForNoUnwind, *this, Opcodes))
return indicatePessimisticFixpoint();
return ChangeStatus::UNCHANGED;
}
};
struct AANoUnwindFunction final : public AANoUnwindImpl {
AANoUnwindFunction(const IRPosition &IRP) : AANoUnwindImpl(IRP) {}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override { STATS_DECLTRACK_FN_ATTR(nounwind) }
};
/// NoUnwind attribute deduction for a call sites.
struct AANoUnwindCallSite final : AANoUnwindImpl {
AANoUnwindCallSite(const IRPosition &IRP) : AANoUnwindImpl(IRP) {}
/// See AbstractAttribute::initialize(...).
void initialize(Attributor &A) override {
AANoUnwindImpl::initialize(A);
Function *F = getAssociatedFunction();
if (!F)
indicatePessimisticFixpoint();
}
/// See AbstractAttribute::updateImpl(...).
ChangeStatus updateImpl(Attributor &A) override {
// TODO: Once we have call site specific value information we can provide
// call site specific liveness information and then it makes
// sense to specialize attributes for call sites arguments instead of
// redirecting requests to the callee argument.
Function *F = getAssociatedFunction();
const IRPosition &FnPos = IRPosition::function(*F);
auto &FnAA = A.getAAFor<AANoUnwind>(*this, FnPos);
return clampStateAndIndicateChange(
getState(),
static_cast<const AANoUnwind::StateType &>(FnAA.getState()));
}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override { STATS_DECLTRACK_CS_ATTR(nounwind); }
};
/// --------------------- Function Return Values -------------------------------
/// "Attribute" that collects all potential returned values and the return
/// instructions that they arise from.
///
/// If there is a unique returned value R, the manifest method will:
/// - mark R with the "returned" attribute, if R is an argument.
class AAReturnedValuesImpl : public AAReturnedValues, public AbstractState {
/// Mapping of values potentially returned by the associated function to the
/// return instructions that might return them.
MapVector<Value *, SmallSetVector<ReturnInst *, 4>> ReturnedValues;
/// Mapping to remember the number of returned values for a call site such
/// that we can avoid updates if nothing changed.
DenseMap<const CallBase *, unsigned> NumReturnedValuesPerKnownAA;
/// Set of unresolved calls returned by the associated function.
SmallSetVector<CallBase *, 4> UnresolvedCalls;
/// State flags
///
///{
bool IsFixed = false;
bool IsValidState = true;
///}
public:
AAReturnedValuesImpl(const IRPosition &IRP) : AAReturnedValues(IRP) {}
/// See AbstractAttribute::initialize(...).
void initialize(Attributor &A) override {
// Reset the state.
IsFixed = false;
IsValidState = true;
ReturnedValues.clear();
Function *F = getAssociatedFunction();
if (!F) {
indicatePessimisticFixpoint();
return;
}
// The map from instruction opcodes to those instructions in the function.
auto &OpcodeInstMap = A.getInfoCache().getOpcodeInstMapForFunction(*F);
// Look through all arguments, if one is marked as returned we are done.
for (Argument &Arg : F->args()) {
if (Arg.hasReturnedAttr()) {
auto &ReturnInstSet = ReturnedValues[&Arg];
for (Instruction *RI : OpcodeInstMap[Instruction::Ret])
ReturnInstSet.insert(cast<ReturnInst>(RI));
indicateOptimisticFixpoint();
return;
}
}
if (!F->hasExactDefinition())
indicatePessimisticFixpoint();
}
/// See AbstractAttribute::manifest(...).
ChangeStatus manifest(Attributor &A) override;
/// See AbstractAttribute::getState(...).
AbstractState &getState() override { return *this; }
/// See AbstractAttribute::getState(...).
const AbstractState &getState() const override { return *this; }
/// See AbstractAttribute::updateImpl(Attributor &A).
ChangeStatus updateImpl(Attributor &A) override;
llvm::iterator_range<iterator> returned_values() override {
return llvm::make_range(ReturnedValues.begin(), ReturnedValues.end());
}
llvm::iterator_range<const_iterator> returned_values() const override {
return llvm::make_range(ReturnedValues.begin(), ReturnedValues.end());
}
const SmallSetVector<CallBase *, 4> &getUnresolvedCalls() const override {
return UnresolvedCalls;
}
/// Return the number of potential return values, -1 if unknown.
size_t getNumReturnValues() const override {
return isValidState() ? ReturnedValues.size() : -1;
}
/// Return an assumed unique return value if a single candidate is found. If
/// there cannot be one, return a nullptr. If it is not clear yet, return the
/// Optional::NoneType.
Optional<Value *> getAssumedUniqueReturnValue(Attributor &A) const;
/// See AbstractState::checkForAllReturnedValues(...).
bool checkForAllReturnedValuesAndReturnInsts(
const function_ref<bool(Value &, const SmallSetVector<ReturnInst *, 4> &)>
&Pred) const override;
/// Pretty print the attribute similar to the IR representation.
const std::string getAsStr() const override;
/// See AbstractState::isAtFixpoint().
bool isAtFixpoint() const override { return IsFixed; }
/// See AbstractState::isValidState().
bool isValidState() const override { return IsValidState; }
/// See AbstractState::indicateOptimisticFixpoint(...).
ChangeStatus indicateOptimisticFixpoint() override {
IsFixed = true;
return ChangeStatus::UNCHANGED;
}
ChangeStatus indicatePessimisticFixpoint() override {
IsFixed = true;
IsValidState = false;
return ChangeStatus::CHANGED;
}
};
ChangeStatus AAReturnedValuesImpl::manifest(Attributor &A) {
ChangeStatus Changed = ChangeStatus::UNCHANGED;
// Bookkeeping.
assert(isValidState());
STATS_DECLTRACK(KnownReturnValues, FunctionReturn,
"Number of function with known return values");
// Check if we have an assumed unique return value that we could manifest.
Optional<Value *> UniqueRV = getAssumedUniqueReturnValue(A);
if (!UniqueRV.hasValue() || !UniqueRV.getValue())
return Changed;
// Bookkeeping.
STATS_DECLTRACK(UniqueReturnValue, FunctionReturn,
"Number of function with unique return");
// Callback to replace the uses of CB with the constant C.
auto ReplaceCallSiteUsersWith = [](CallBase &CB, Constant &C) {
if (CB.getNumUses() == 0 || CB.isMustTailCall())
return ChangeStatus::UNCHANGED;
replaceAllInstructionUsesWith(CB, C);
return ChangeStatus::CHANGED;
};
// If the assumed unique return value is an argument, annotate it.
if (auto *UniqueRVArg = dyn_cast<Argument>(UniqueRV.getValue())) {
// TODO: This should be handled differently!
this->AnchorVal = UniqueRVArg;
this->KindOrArgNo = UniqueRVArg->getArgNo();
Changed = IRAttribute::manifest(A);
} else if (auto *RVC = dyn_cast<Constant>(UniqueRV.getValue())) {
// We can replace the returned value with the unique returned constant.
Value &AnchorValue = getAnchorValue();
if (Function *F = dyn_cast<Function>(&AnchorValue)) {
for (const Use &U : F->uses())
if (CallBase *CB = dyn_cast<CallBase>(U.getUser()))
if (CB->isCallee(&U)) {
Constant *RVCCast =
CB->getType() == RVC->getType()
? RVC
: ConstantExpr::getTruncOrBitCast(RVC, CB->getType());
Changed = ReplaceCallSiteUsersWith(*CB, *RVCCast) | Changed;
}
} else {
assert(isa<CallBase>(AnchorValue) &&
"Expcected a function or call base anchor!");
Constant *RVCCast =
AnchorValue.getType() == RVC->getType()
? RVC
: ConstantExpr::getTruncOrBitCast(RVC, AnchorValue.getType());
Changed = ReplaceCallSiteUsersWith(cast<CallBase>(AnchorValue), *RVCCast);
}
if (Changed == ChangeStatus::CHANGED)
STATS_DECLTRACK(UniqueConstantReturnValue, FunctionReturn,
"Number of function returns replaced by constant return");
}
return Changed;
}
const std::string AAReturnedValuesImpl::getAsStr() const {
return (isAtFixpoint() ? "returns(#" : "may-return(#") +
(isValidState() ? std::to_string(getNumReturnValues()) : "?") +
")[#UC: " + std::to_string(UnresolvedCalls.size()) + "]";
}
Optional<Value *>
AAReturnedValuesImpl::getAssumedUniqueReturnValue(Attributor &A) const {
// If checkForAllReturnedValues provides a unique value, ignoring potential
// undef values that can also be present, it is assumed to be the actual
// return value and forwarded to the caller of this method. If there are
// multiple, a nullptr is returned indicating there cannot be a unique
// returned value.
Optional<Value *> UniqueRV;
auto Pred = [&](Value &RV) -> bool {
// If we found a second returned value and neither the current nor the saved
// one is an undef, there is no unique returned value. Undefs are special
// since we can pretend they have any value.
if (UniqueRV.hasValue() && UniqueRV != &RV &&
!(isa<UndefValue>(RV) || isa<UndefValue>(UniqueRV.getValue()))) {
UniqueRV = nullptr;
return false;
}
// Do not overwrite a value with an undef.
if (!UniqueRV.hasValue() || !isa<UndefValue>(RV))
UniqueRV = &RV;
return true;
};
if (!A.checkForAllReturnedValues(Pred, *this))
UniqueRV = nullptr;
return UniqueRV;
}
bool AAReturnedValuesImpl::checkForAllReturnedValuesAndReturnInsts(
const function_ref<bool(Value &, const SmallSetVector<ReturnInst *, 4> &)>
&Pred) const {
if (!isValidState())
return false;
// Check all returned values but ignore call sites as long as we have not
// encountered an overdefined one during an update.
for (auto &It : ReturnedValues) {
Value *RV = It.first;
CallBase *CB = dyn_cast<CallBase>(RV);
if (CB && !UnresolvedCalls.count(CB))
continue;
if (!Pred(*RV, It.second))
return false;
}
return true;
}
ChangeStatus AAReturnedValuesImpl::updateImpl(Attributor &A) {
size_t NumUnresolvedCalls = UnresolvedCalls.size();
bool Changed = false;
// State used in the value traversals starting in returned values.
struct RVState {
// The map in which we collect return values -> return instrs.
decltype(ReturnedValues) &RetValsMap;
// The flag to indicate a change.
bool &Changed;
// The return instrs we come from.
SmallSetVector<ReturnInst *, 4> RetInsts;
};
// Callback for a leaf value returned by the associated function.
auto VisitValueCB = [](Value &Val, RVState &RVS, bool) -> bool {
auto Size = RVS.RetValsMap[&Val].size();
RVS.RetValsMap[&Val].insert(RVS.RetInsts.begin(), RVS.RetInsts.end());
bool Inserted = RVS.RetValsMap[&Val].size() != Size;
RVS.Changed |= Inserted;
LLVM_DEBUG({
if (Inserted)
dbgs() << "[AAReturnedValues] 1 Add new returned value " << Val
<< " => " << RVS.RetInsts.size() << "\n";
});
return true;
};
// Helper method to invoke the generic value traversal.
auto VisitReturnedValue = [&](Value &RV, RVState &RVS) {
IRPosition RetValPos = IRPosition::value(RV);
return genericValueTraversal<AAReturnedValues, RVState>(A, RetValPos, *this,
RVS, VisitValueCB);
};
// Callback for all "return intructions" live in the associated function.
auto CheckReturnInst = [this, &VisitReturnedValue, &Changed](Instruction &I) {
ReturnInst &Ret = cast<ReturnInst>(I);
RVState RVS({ReturnedValues, Changed, {}});
RVS.RetInsts.insert(&Ret);
return VisitReturnedValue(*Ret.getReturnValue(), RVS);
};
// Start by discovering returned values from all live returned instructions in
// the associated function.
if (!A.checkForAllInstructions(CheckReturnInst, *this, {Instruction::Ret}))
return indicatePessimisticFixpoint();
// Once returned values "directly" present in the code are handled we try to
// resolve returned calls.
decltype(ReturnedValues) NewRVsMap;
for (auto &It : ReturnedValues) {
LLVM_DEBUG(dbgs() << "[AAReturnedValues] Returned value: " << *It.first
<< " by #" << It.second.size() << " RIs\n");
CallBase *CB = dyn_cast<CallBase>(It.first);
if (!CB || UnresolvedCalls.count(CB))
continue;
if (!CB->getCalledFunction()) {
LLVM_DEBUG(dbgs() << "[AAReturnedValues] Unresolved call: " << *CB
<< "\n");
UnresolvedCalls.insert(CB);
continue;
}
// TODO: use the function scope once we have call site AAReturnedValues.
const auto &RetValAA = A.getAAFor<AAReturnedValues>(
*this, IRPosition::function(*CB->getCalledFunction()));
LLVM_DEBUG(dbgs() << "[AAReturnedValues] Found another AAReturnedValues: "
<< RetValAA << "\n");
// Skip dead ends, thus if we do not know anything about the returned
// call we mark it as unresolved and it will stay that way.
if (!RetValAA.getState().isValidState()) {
LLVM_DEBUG(dbgs() << "[AAReturnedValues] Unresolved call: " << *CB
<< "\n");
UnresolvedCalls.insert(CB);
continue;
}
// Do not try to learn partial information. If the callee has unresolved
// return values we will treat the call as unresolved/opaque.
auto &RetValAAUnresolvedCalls = RetValAA.getUnresolvedCalls();
if (!RetValAAUnresolvedCalls.empty()) {
UnresolvedCalls.insert(CB);
continue;
}
// Now check if we can track transitively returned values. If possible, thus
// if all return value can be represented in the current scope, do so.
bool Unresolved = false;
for (auto &RetValAAIt : RetValAA.returned_values()) {
Value *RetVal = RetValAAIt.first;
if (isa<Argument>(RetVal) || isa<CallBase>(RetVal) ||
isa<Constant>(RetVal))
continue;
// Anything that did not fit in the above categories cannot be resolved,
// mark the call as unresolved.
LLVM_DEBUG(dbgs() << "[AAReturnedValues] transitively returned value "
"cannot be translated: "
<< *RetVal << "\n");
UnresolvedCalls.insert(CB);
Unresolved = true;
break;
}
if (Unresolved)
continue;
// Now track transitively returned values.
unsigned &NumRetAA = NumReturnedValuesPerKnownAA[CB];
if (NumRetAA == RetValAA.getNumReturnValues()) {
LLVM_DEBUG(dbgs() << "[AAReturnedValues] Skip call as it has not "
"changed since it was seen last\n");
continue;
}
NumRetAA = RetValAA.getNumReturnValues();
for (auto &RetValAAIt : RetValAA.returned_values()) {
Value *RetVal = RetValAAIt.first;
if (Argument *Arg = dyn_cast<Argument>(RetVal)) {
// Arguments are mapped to call site operands and we begin the traversal
// again.
bool Unused = false;
RVState RVS({NewRVsMap, Unused, RetValAAIt.second});
VisitReturnedValue(*CB->getArgOperand(Arg->getArgNo()), RVS);
continue;
} else if (isa<CallBase>(RetVal)) {
// Call sites are resolved by the callee attribute over time, no need to
// do anything for us.
continue;
} else if (isa<Constant>(RetVal)) {
// Constants are valid everywhere, we can simply take them.
NewRVsMap[RetVal].insert(It.second.begin(), It.second.end());
continue;
}
}
}
// To avoid modifications to the ReturnedValues map while we iterate over it
// we kept record of potential new entries in a copy map, NewRVsMap.
for (auto &It : NewRVsMap) {
assert(!It.second.empty() && "Entry does not add anything.");
auto &ReturnInsts = ReturnedValues[It.first];
for (ReturnInst *RI : It.second)
if (ReturnInsts.insert(RI)) {
LLVM_DEBUG(dbgs() << "[AAReturnedValues] Add new returned value "
<< *It.first << " => " << *RI << "\n");
Changed = true;
}
}
Changed |= (NumUnresolvedCalls != UnresolvedCalls.size());
return Changed ? ChangeStatus::CHANGED : ChangeStatus::UNCHANGED;
}
struct AAReturnedValuesFunction final : public AAReturnedValuesImpl {
AAReturnedValuesFunction(const IRPosition &IRP) : AAReturnedValuesImpl(IRP) {}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override { STATS_DECLTRACK_ARG_ATTR(returned) }
};
/// Returned values information for a call sites.
struct AAReturnedValuesCallSite final : AAReturnedValuesImpl {
AAReturnedValuesCallSite(const IRPosition &IRP) : AAReturnedValuesImpl(IRP) {}
/// See AbstractAttribute::initialize(...).
void initialize(Attributor &A) override {
// TODO: Once we have call site specific value information we can provide
// call site specific liveness information and then it makes
// sense to specialize attributes for call sites instead of
// redirecting requests to the callee.
llvm_unreachable("Abstract attributes for returned values are not "
"supported for call sites yet!");
}
/// See AbstractAttribute::updateImpl(...).
ChangeStatus updateImpl(Attributor &A) override {
return indicatePessimisticFixpoint();
}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override {}
};
/// ------------------------ NoSync Function Attribute -------------------------
struct AANoSyncImpl : AANoSync {
AANoSyncImpl(const IRPosition &IRP) : AANoSync(IRP) {}
const std::string getAsStr() const override {
return getAssumed() ? "nosync" : "may-sync";
}
/// See AbstractAttribute::updateImpl(...).
ChangeStatus updateImpl(Attributor &A) override;
/// Helper function used to determine whether an instruction is non-relaxed
/// atomic. In other words, if an atomic instruction does not have unordered
/// or monotonic ordering
static bool isNonRelaxedAtomic(Instruction *I);
/// Helper function used to determine whether an instruction is volatile.
static bool isVolatile(Instruction *I);
/// Helper function uset to check if intrinsic is volatile (memcpy, memmove,
/// memset).
static bool isNoSyncIntrinsic(Instruction *I);
};
bool AANoSyncImpl::isNonRelaxedAtomic(Instruction *I) {
if (!I->isAtomic())
return false;
AtomicOrdering Ordering;
switch (I->getOpcode()) {
case Instruction::AtomicRMW:
Ordering = cast<AtomicRMWInst>(I)->getOrdering();
break;
case Instruction::Store:
Ordering = cast<StoreInst>(I)->getOrdering();
break;
case Instruction::Load:
Ordering = cast<LoadInst>(I)->getOrdering();
break;
case Instruction::Fence: {
auto *FI = cast<FenceInst>(I);
if (FI->getSyncScopeID() == SyncScope::SingleThread)
return false;
Ordering = FI->getOrdering();
break;
}
case Instruction::AtomicCmpXchg: {
AtomicOrdering Success = cast<AtomicCmpXchgInst>(I)->getSuccessOrdering();
AtomicOrdering Failure = cast<AtomicCmpXchgInst>(I)->getFailureOrdering();
// Only if both are relaxed, than it can be treated as relaxed.
// Otherwise it is non-relaxed.
if (Success != AtomicOrdering::Unordered &&
Success != AtomicOrdering::Monotonic)
return true;
if (Failure != AtomicOrdering::Unordered &&
Failure != AtomicOrdering::Monotonic)
return true;
return false;
}
default:
llvm_unreachable(
"New atomic operations need to be known in the attributor.");
}
// Relaxed.
if (Ordering == AtomicOrdering::Unordered ||
Ordering == AtomicOrdering::Monotonic)
return false;
return true;
}
/// Checks if an intrinsic is nosync. Currently only checks mem* intrinsics.
/// FIXME: We should ipmrove the handling of intrinsics.
bool AANoSyncImpl::isNoSyncIntrinsic(Instruction *I) {
if (auto *II = dyn_cast<IntrinsicInst>(I)) {
switch (II->getIntrinsicID()) {
/// Element wise atomic memory intrinsics are can only be unordered,
/// therefore nosync.
case Intrinsic::memset_element_unordered_atomic:
case Intrinsic::memmove_element_unordered_atomic:
case Intrinsic::memcpy_element_unordered_atomic:
return true;
case Intrinsic::memset:
case Intrinsic::memmove:
case Intrinsic::memcpy:
if (!cast<MemIntrinsic>(II)->isVolatile())
return true;
return false;
default:
return false;
}
}
return false;
}
bool AANoSyncImpl::isVolatile(Instruction *I) {
assert(!ImmutableCallSite(I) && !isa<CallBase>(I) &&
"Calls should not be checked here");
switch (I->getOpcode()) {
case Instruction::AtomicRMW:
return cast<AtomicRMWInst>(I)->isVolatile();
case Instruction::Store:
return cast<StoreInst>(I)->isVolatile();
case Instruction::Load:
return cast<LoadInst>(I)->isVolatile();
case Instruction::AtomicCmpXchg:
return cast<AtomicCmpXchgInst>(I)->isVolatile();
default:
return false;
}
}
ChangeStatus AANoSyncImpl::updateImpl(Attributor &A) {
auto CheckRWInstForNoSync = [&](Instruction &I) {
/// We are looking for volatile instructions or Non-Relaxed atomics.
/// FIXME: We should improve the handling of intrinsics.
if (isa<IntrinsicInst>(&I) && isNoSyncIntrinsic(&I))
return true;
if (ImmutableCallSite ICS = ImmutableCallSite(&I)) {
if (ICS.hasFnAttr(Attribute::NoSync))
return true;
const auto &NoSyncAA =
A.getAAFor<AANoSync>(*this, IRPosition::callsite_function(ICS));
if (NoSyncAA.isAssumedNoSync())
return true;
return false;
}
if (!isVolatile(&I) && !isNonRelaxedAtomic(&I))
return true;
return false;
};
auto CheckForNoSync = [&](Instruction &I) {
// At this point we handled all read/write effects and they are all
// nosync, so they can be skipped.
if (I.mayReadOrWriteMemory())
return true;
// non-convergent and readnone imply nosync.
return !ImmutableCallSite(&I).isConvergent();
};
if (!A.checkForAllReadWriteInstructions(CheckRWInstForNoSync, *this) ||
!A.checkForAllCallLikeInstructions(CheckForNoSync, *this))
return indicatePessimisticFixpoint();
return ChangeStatus::UNCHANGED;
}
struct AANoSyncFunction final : public AANoSyncImpl {
AANoSyncFunction(const IRPosition &IRP) : AANoSyncImpl(IRP) {}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override { STATS_DECLTRACK_FN_ATTR(nosync) }
};
/// NoSync attribute deduction for a call sites.
struct AANoSyncCallSite final : AANoSyncImpl {
AANoSyncCallSite(const IRPosition &IRP) : AANoSyncImpl(IRP) {}
/// See AbstractAttribute::initialize(...).
void initialize(Attributor &A) override {
AANoSyncImpl::initialize(A);
Function *F = getAssociatedFunction();
if (!F)
indicatePessimisticFixpoint();
}
/// See AbstractAttribute::updateImpl(...).
ChangeStatus updateImpl(Attributor &A) override {
// TODO: Once we have call site specific value information we can provide
// call site specific liveness information and then it makes
// sense to specialize attributes for call sites arguments instead of
// redirecting requests to the callee argument.
Function *F = getAssociatedFunction();
const IRPosition &FnPos = IRPosition::function(*F);
auto &FnAA = A.getAAFor<AANoSync>(*this, FnPos);
return clampStateAndIndicateChange(
getState(), static_cast<const AANoSync::StateType &>(FnAA.getState()));
}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override { STATS_DECLTRACK_CS_ATTR(nosync); }
};
/// ------------------------ No-Free Attributes ----------------------------
struct AANoFreeImpl : public AANoFree {
AANoFreeImpl(const IRPosition &IRP) : AANoFree(IRP) {}
/// See AbstractAttribute::updateImpl(...).
ChangeStatus updateImpl(Attributor &A) override {
auto CheckForNoFree = [&](Instruction &I) {
ImmutableCallSite ICS(&I);
if (ICS.hasFnAttr(Attribute::NoFree))
return true;
const auto &NoFreeAA =
A.getAAFor<AANoFree>(*this, IRPosition::callsite_function(ICS));
return NoFreeAA.isAssumedNoFree();
};
if (!A.checkForAllCallLikeInstructions(CheckForNoFree, *this))
return indicatePessimisticFixpoint();
return ChangeStatus::UNCHANGED;
}
/// See AbstractAttribute::getAsStr().
const std::string getAsStr() const override {
return getAssumed() ? "nofree" : "may-free";
}
};
struct AANoFreeFunction final : public AANoFreeImpl {
AANoFreeFunction(const IRPosition &IRP) : AANoFreeImpl(IRP) {}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override { STATS_DECLTRACK_FN_ATTR(nofree) }
};
/// NoFree attribute deduction for a call sites.
struct AANoFreeCallSite final : AANoFreeImpl {
AANoFreeCallSite(const IRPosition &IRP) : AANoFreeImpl(IRP) {}
/// See AbstractAttribute::initialize(...).
void initialize(Attributor &A) override {
AANoFreeImpl::initialize(A);
Function *F = getAssociatedFunction();
if (!F)
indicatePessimisticFixpoint();
}
/// See AbstractAttribute::updateImpl(...).
ChangeStatus updateImpl(Attributor &A) override {
// TODO: Once we have call site specific value information we can provide
// call site specific liveness information and then it makes
// sense to specialize attributes for call sites arguments instead of
// redirecting requests to the callee argument.
Function *F = getAssociatedFunction();
const IRPosition &FnPos = IRPosition::function(*F);
auto &FnAA = A.getAAFor<AANoFree>(*this, FnPos);
return clampStateAndIndicateChange(
getState(), static_cast<const AANoFree::StateType &>(FnAA.getState()));
}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override { STATS_DECLTRACK_CS_ATTR(nofree); }
};
/// NoFree attribute for floating values.
struct AANoFreeFloating : AANoFreeImpl {
AANoFreeFloating(const IRPosition &IRP) : AANoFreeImpl(IRP) {}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override{STATS_DECLTRACK_FLOATING_ATTR(nofree)}
/// See Abstract Attribute::updateImpl(...).
ChangeStatus updateImpl(Attributor &A) override {
const IRPosition &IRP = getIRPosition();
const auto &NoFreeAA =
A.getAAFor<AANoFree>(*this, IRPosition::function_scope(IRP));
if (NoFreeAA.isAssumedNoFree())
return ChangeStatus::UNCHANGED;
Value &AssociatedValue = getIRPosition().getAssociatedValue();
auto Pred = [&](const Use &U, bool &Follow) -> bool {
Instruction *UserI = cast<Instruction>(U.getUser());
if (auto *CB = dyn_cast<CallBase>(UserI)) {
if (CB->isBundleOperand(&U))
return false;
if (!CB->isArgOperand(&U))
return true;
unsigned ArgNo = CB->getArgOperandNo(&U);
const auto &NoFreeArg = A.getAAFor<AANoFree>(
*this, IRPosition::callsite_argument(*CB, ArgNo));
return NoFreeArg.isAssumedNoFree();
}
if (isa<GetElementPtrInst>(UserI) || isa<BitCastInst>(UserI) ||
isa<PHINode>(UserI) || isa<SelectInst>(UserI)) {
Follow = true;
return true;
}
// Unknown user.
return false;
};
if (!A.checkForAllUses(Pred, *this, AssociatedValue))
return indicatePessimisticFixpoint();
return ChangeStatus::UNCHANGED;
}
};
/// NoFree attribute for a call site argument.
struct AANoFreeArgument final : AANoFreeFloating {
AANoFreeArgument(const IRPosition &IRP) : AANoFreeFloating(IRP) {}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override { STATS_DECLTRACK_ARG_ATTR(nofree) }
};
/// NoFree attribute for call site arguments.
struct AANoFreeCallSiteArgument final : AANoFreeFloating {
AANoFreeCallSiteArgument(const IRPosition &IRP) : AANoFreeFloating(IRP) {}
/// See AbstractAttribute::updateImpl(...).
ChangeStatus updateImpl(Attributor &A) override {
// TODO: Once we have call site specific value information we can provide
// call site specific liveness information and then it makes
// sense to specialize attributes for call sites arguments instead of
// redirecting requests to the callee argument.
Argument *Arg = getAssociatedArgument();
if (!Arg)
return indicatePessimisticFixpoint();
const IRPosition &ArgPos = IRPosition::argument(*Arg);
auto &ArgAA = A.getAAFor<AANoFree>(*this, ArgPos);
return clampStateAndIndicateChange(
getState(), static_cast<const AANoFree::StateType &>(ArgAA.getState()));
}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override{STATS_DECLTRACK_CSARG_ATTR(nofree)};
};
/// NoFree attribute for function return value.
struct AANoFreeReturned final : AANoFreeFloating {
AANoFreeReturned(const IRPosition &IRP) : AANoFreeFloating(IRP) {
llvm_unreachable("NoFree is not applicable to function returns!");
}
/// See AbstractAttribute::initialize(...).
void initialize(Attributor &A) override {
llvm_unreachable("NoFree is not applicable to function returns!");
}
/// See AbstractAttribute::updateImpl(...).
ChangeStatus updateImpl(Attributor &A) override {
llvm_unreachable("NoFree is not applicable to function returns!");
}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override {}
};
/// NoFree attribute deduction for a call site return value.
struct AANoFreeCallSiteReturned final : AANoFreeFloating {
AANoFreeCallSiteReturned(const IRPosition &IRP) : AANoFreeFloating(IRP) {}
ChangeStatus manifest(Attributor &A) override {
return ChangeStatus::UNCHANGED;
}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override { STATS_DECLTRACK_CSRET_ATTR(nofree) }
};
/// ------------------------ NonNull Argument Attribute ------------------------
static int64_t getKnownNonNullAndDerefBytesForUse(
Attributor &A, AbstractAttribute &QueryingAA, Value &AssociatedValue,
const Use *U, const Instruction *I, bool &IsNonNull, bool &TrackUse) {
TrackUse = false;
const Value *UseV = U->get();
if (!UseV->getType()->isPointerTy())
return 0;
Type *PtrTy = UseV->getType();
const Function *F = I->getFunction();
bool NullPointerIsDefined =
F ? llvm::NullPointerIsDefined(F, PtrTy->getPointerAddressSpace()) : true;
const DataLayout &DL = A.getInfoCache().getDL();
if (ImmutableCallSite ICS = ImmutableCallSite(I)) {
if (ICS.isBundleOperand(U))
return 0;
if (ICS.isCallee(U)) {
IsNonNull |= !NullPointerIsDefined;
return 0;
}
unsigned ArgNo = ICS.getArgumentNo(U);
IRPosition IRP = IRPosition::callsite_argument(ICS, ArgNo);
// As long as we only use known information there is no need to track
// dependences here.
auto &DerefAA = A.getAAFor<AADereferenceable>(QueryingAA, IRP,
/* TrackDependence */ false);
IsNonNull |= DerefAA.isKnownNonNull();
return DerefAA.getKnownDereferenceableBytes();
}
// We need to follow common pointer manipulation uses to the accesses they
// feed into. We can try to be smart to avoid looking through things we do not
// like for now, e.g., non-inbounds GEPs.
if (isa<CastInst>(I)) {
TrackUse = true;
return 0;
}
if (auto *GEP = dyn_cast<GetElementPtrInst>(I))
if (GEP->hasAllConstantIndices()) {
TrackUse = true;
return 0;
}
int64_t Offset;
if (const Value *Base = getBasePointerOfAccessPointerOperand(I, Offset, DL)) {
if (Base == &AssociatedValue &&
Attributor::getPointerOperand(I, /* AllowVolatile */ false) == UseV) {
int64_t DerefBytes =
(int64_t)DL.getTypeStoreSize(PtrTy->getPointerElementType()) + Offset;
IsNonNull |= !NullPointerIsDefined;
return std::max(int64_t(0), DerefBytes);
}
}
/// Corner case when an offset is 0.
if (const Value *Base = getBasePointerOfAccessPointerOperand(
I, Offset, DL, /*AllowNonInbounds*/ true)) {
if (Offset == 0 && Base == &AssociatedValue &&
Attributor::getPointerOperand(I, /* AllowVolatile */ false) == UseV) {
int64_t DerefBytes =
(int64_t)DL.getTypeStoreSize(PtrTy->getPointerElementType());
IsNonNull |= !NullPointerIsDefined;
return std::max(int64_t(0), DerefBytes);
}
}
return 0;
}
struct AANonNullImpl : AANonNull {
AANonNullImpl(const IRPosition &IRP)
: AANonNull(IRP),
NullIsDefined(NullPointerIsDefined(
getAnchorScope(),
getAssociatedValue().getType()->getPointerAddressSpace())) {}
/// See AbstractAttribute::initialize(...).
void initialize(Attributor &A) override {
if (!NullIsDefined &&
hasAttr({Attribute::NonNull, Attribute::Dereferenceable}))
indicateOptimisticFixpoint();
else if (isa<ConstantPointerNull>(getAssociatedValue()))
indicatePessimisticFixpoint();
else
AANonNull::initialize(A);
}
/// See AAFromMustBeExecutedContext
bool followUse(Attributor &A, const Use *U, const Instruction *I) {
bool IsNonNull = false;
bool TrackUse = false;
getKnownNonNullAndDerefBytesForUse(A, *this, getAssociatedValue(), U, I,
IsNonNull, TrackUse);
setKnown(IsNonNull);
return TrackUse;
}
/// See AbstractAttribute::getAsStr().
const std::string getAsStr() const override {
return getAssumed() ? "nonnull" : "may-null";
}
/// Flag to determine if the underlying value can be null and still allow
/// valid accesses.
const bool NullIsDefined;
};
/// NonNull attribute for a floating value.
struct AANonNullFloating
: AAFromMustBeExecutedContext<AANonNull, AANonNullImpl> {
using Base = AAFromMustBeExecutedContext<AANonNull, AANonNullImpl>;
AANonNullFloating(const IRPosition &IRP) : Base(IRP) {}
/// See AbstractAttribute::updateImpl(...).
ChangeStatus updateImpl(Attributor &A) override {
ChangeStatus Change = Base::updateImpl(A);
if (isKnownNonNull())
return Change;
if (!NullIsDefined) {
const auto &DerefAA =
A.getAAFor<AADereferenceable>(*this, getIRPosition());
if (DerefAA.getAssumedDereferenceableBytes())
return Change;
}
const DataLayout &DL = A.getDataLayout();
DominatorTree *DT = nullptr;
InformationCache &InfoCache = A.getInfoCache();
if (const Function *Fn = getAnchorScope())
DT = InfoCache.getAnalysisResultForFunction<DominatorTreeAnalysis>(*Fn);
auto VisitValueCB = [&](Value &V, AANonNull::StateType &T,
bool Stripped) -> bool {
const auto &AA = A.getAAFor<AANonNull>(*this, IRPosition::value(V));
if (!Stripped && this == &AA) {
if (!isKnownNonZero(&V, DL, 0, /* TODO: AC */ nullptr, getCtxI(), DT))
T.indicatePessimisticFixpoint();
} else {
// Use abstract attribute information.
const AANonNull::StateType &NS =
static_cast<const AANonNull::StateType &>(AA.getState());
T ^= NS;
}
return T.isValidState();
};
StateType T;
if (!genericValueTraversal<AANonNull, StateType>(A, getIRPosition(), *this,
T, VisitValueCB))
return indicatePessimisticFixpoint();
return clampStateAndIndicateChange(getState(), T);
}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override { STATS_DECLTRACK_FNRET_ATTR(nonnull) }
};
/// NonNull attribute for function return value.
struct AANonNullReturned final
: AAReturnedFromReturnedValues<AANonNull, AANonNullImpl> {
AANonNullReturned(const IRPosition &IRP)
: AAReturnedFromReturnedValues<AANonNull, AANonNullImpl>(IRP) {}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override { STATS_DECLTRACK_FNRET_ATTR(nonnull) }
};
/// NonNull attribute for function argument.
struct AANonNullArgument final
: AAArgumentFromCallSiteArgumentsAndMustBeExecutedContext<AANonNull,
AANonNullImpl> {
AANonNullArgument(const IRPosition &IRP)
: AAArgumentFromCallSiteArgumentsAndMustBeExecutedContext<AANonNull,
AANonNullImpl>(
IRP) {}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override { STATS_DECLTRACK_ARG_ATTR(nonnull) }
};
struct AANonNullCallSiteArgument final : AANonNullFloating {
AANonNullCallSiteArgument(const IRPosition &IRP) : AANonNullFloating(IRP) {}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override { STATS_DECLTRACK_CSARG_ATTR(nonnull) }
};
/// NonNull attribute for a call site return position.
struct AANonNullCallSiteReturned final
: AACallSiteReturnedFromReturnedAndMustBeExecutedContext<AANonNull,
AANonNullImpl> {
AANonNullCallSiteReturned(const IRPosition &IRP)
: AACallSiteReturnedFromReturnedAndMustBeExecutedContext<AANonNull,
AANonNullImpl>(
IRP) {}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override { STATS_DECLTRACK_CSRET_ATTR(nonnull) }
};
/// ------------------------ No-Recurse Attributes ----------------------------
struct AANoRecurseImpl : public AANoRecurse {
AANoRecurseImpl(const IRPosition &IRP) : AANoRecurse(IRP) {}
/// See AbstractAttribute::getAsStr()
const std::string getAsStr() const override {
return getAssumed() ? "norecurse" : "may-recurse";
}
};
struct AANoRecurseFunction final : AANoRecurseImpl {
AANoRecurseFunction(const IRPosition &IRP) : AANoRecurseImpl(IRP) {}
/// See AbstractAttribute::initialize(...).
void initialize(Attributor &A) override {
AANoRecurseImpl::initialize(A);
if (const Function *F = getAnchorScope())
if (A.getInfoCache().getSccSize(*F) == 1)
return;
indicatePessimisticFixpoint();
}
/// See AbstractAttribute::updateImpl(...).
ChangeStatus updateImpl(Attributor &A) override {
auto CheckForNoRecurse = [&](Instruction &I) {
ImmutableCallSite ICS(&I);
if (ICS.hasFnAttr(Attribute::NoRecurse))
return true;
const auto &NoRecurseAA =
A.getAAFor<AANoRecurse>(*this, IRPosition::callsite_function(ICS));
if (!NoRecurseAA.isAssumedNoRecurse())
return false;
// Recursion to the same function
if (ICS.getCalledFunction() == getAnchorScope())
return false;
return true;
};
if (!A.checkForAllCallLikeInstructions(CheckForNoRecurse, *this))
return indicatePessimisticFixpoint();
return ChangeStatus::UNCHANGED;
}
void trackStatistics() const override { STATS_DECLTRACK_FN_ATTR(norecurse) }
};
/// NoRecurse attribute deduction for a call sites.
struct AANoRecurseCallSite final : AANoRecurseImpl {
AANoRecurseCallSite(const IRPosition &IRP) : AANoRecurseImpl(IRP) {}
/// See AbstractAttribute::initialize(...).
void initialize(Attributor &A) override {
AANoRecurseImpl::initialize(A);
Function *F = getAssociatedFunction();
if (!F)
indicatePessimisticFixpoint();
}
/// See AbstractAttribute::updateImpl(...).
ChangeStatus updateImpl(Attributor &A) override {
// TODO: Once we have call site specific value information we can provide
// call site specific liveness information and then it makes
// sense to specialize attributes for call sites arguments instead of
// redirecting requests to the callee argument.
Function *F = getAssociatedFunction();
const IRPosition &FnPos = IRPosition::function(*F);
auto &FnAA = A.getAAFor<AANoRecurse>(*this, FnPos);
return clampStateAndIndicateChange(
getState(),
static_cast<const AANoRecurse::StateType &>(FnAA.getState()));
}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override { STATS_DECLTRACK_CS_ATTR(norecurse); }
};
/// -------------------- Undefined-Behavior Attributes ------------------------
struct AAUndefinedBehaviorImpl : public AAUndefinedBehavior {
AAUndefinedBehaviorImpl(const IRPosition &IRP) : AAUndefinedBehavior(IRP) {}
/// See AbstractAttribute::updateImpl(...).
// through a pointer (i.e. also branches etc.)
ChangeStatus updateImpl(Attributor &A) override {
const size_t UBPrevSize = KnownUBInsts.size();
const size_t NoUBPrevSize = AssumedNoUBInsts.size();
auto InspectMemAccessInstForUB = [&](Instruction &I) {
// Skip instructions that are already saved.
if (AssumedNoUBInsts.count(&I) || KnownUBInsts.count(&I))
return true;
// If we reach here, we know we have an instruction
// that accesses memory through a pointer operand,
// for which getPointerOperand() should give it to us.
const Value *PtrOp =
Attributor::getPointerOperand(&I, /* AllowVolatile */ true);
assert(PtrOp &&
"Expected pointer operand of memory accessing instruction");
// A memory access through a pointer is considered UB
// only if the pointer has constant null value.
// TODO: Expand it to not only check constant values.
if (!isa<ConstantPointerNull>(PtrOp)) {
AssumedNoUBInsts.insert(&I);
return true;
}
const Type *PtrTy = PtrOp->getType();
// Because we only consider instructions inside functions,
// assume that a parent function exists.
const Function *F = I.getFunction();
// A memory access using constant null pointer is only considered UB
// if null pointer is _not_ defined for the target platform.
if (llvm::NullPointerIsDefined(F, PtrTy->getPointerAddressSpace()))
AssumedNoUBInsts.insert(&I);
else
KnownUBInsts.insert(&I);
return true;
};
auto InspectBrInstForUB = [&](Instruction &I) {
// A conditional branch instruction is considered UB if it has `undef`
// condition.
// Skip instructions that are already saved.
if (AssumedNoUBInsts.count(&I) || KnownUBInsts.count(&I))
return true;
// We know we have a branch instruction.
auto BrInst = cast<BranchInst>(&I);
// Unconditional branches are never considered UB.
if (BrInst->isUnconditional())
return true;
// Either we stopped and the appropriate action was taken,
// or we got back a simplified value to continue.
Optional<Value *> SimplifiedCond =
stopOnUndefOrAssumed(A, BrInst->getCondition(), BrInst);
if (!SimplifiedCond.hasValue())
return true;
AssumedNoUBInsts.insert(&I);
return true;
};
A.checkForAllInstructions(InspectMemAccessInstForUB, *this,
{Instruction::Load, Instruction::Store,
Instruction::AtomicCmpXchg,
Instruction::AtomicRMW});
A.checkForAllInstructions(InspectBrInstForUB, *this, {Instruction::Br});
if (NoUBPrevSize != AssumedNoUBInsts.size() ||
UBPrevSize != KnownUBInsts.size())
return ChangeStatus::CHANGED;
return ChangeStatus::UNCHANGED;
}
bool isKnownToCauseUB(Instruction *I) const override {
return KnownUBInsts.count(I);
}
bool isAssumedToCauseUB(Instruction *I) const override {
// In simple words, if an instruction is not in the assumed to _not_
// cause UB, then it is assumed UB (that includes those
// in the KnownUBInsts set). The rest is boilerplate
// is to ensure that it is one of the instructions we test
// for UB.
switch (I->getOpcode()) {
case Instruction::Load:
case Instruction::Store:
case Instruction::AtomicCmpXchg:
case Instruction::AtomicRMW:
return !AssumedNoUBInsts.count(I);
case Instruction::Br: {
auto BrInst = cast<BranchInst>(I);
if (BrInst->isUnconditional())
return false;
return !AssumedNoUBInsts.count(I);
} break;
default:
return false;
}
return false;
}
ChangeStatus manifest(Attributor &A) override {
if (KnownUBInsts.empty())
return ChangeStatus::UNCHANGED;
for (Instruction *I : KnownUBInsts)
A.changeToUnreachableAfterManifest(I);
return ChangeStatus::CHANGED;
}
/// See AbstractAttribute::getAsStr()
const std::string getAsStr() const override {
return getAssumed() ? "undefined-behavior" : "no-ub";
}
/// Note: The correctness of this analysis depends on the fact that the
/// following 2 sets will stop changing after some point.
/// "Change" here means that their size changes.
/// The size of each set is monotonically increasing
/// (we only add items to them) and it is upper bounded by the number of
/// instructions in the processed function (we can never save more
/// elements in either set than this number). Hence, at some point,
/// they will stop increasing.
/// Consequently, at some point, both sets will have stopped
/// changing, effectively making the analysis reach a fixpoint.
/// Note: These 2 sets are disjoint and an instruction can be considered
/// one of 3 things:
/// 1) Known to cause UB (AAUndefinedBehavior could prove it) and put it in
/// the KnownUBInsts set.
/// 2) Assumed to cause UB (in every updateImpl, AAUndefinedBehavior
/// has a reason to assume it).
/// 3) Assumed to not cause UB. very other instruction - AAUndefinedBehavior
/// could not find a reason to assume or prove that it can cause UB,
/// hence it assumes it doesn't. We have a set for these instructions
/// so that we don't reprocess them in every update.
/// Note however that instructions in this set may cause UB.
protected:
/// A set of all live instructions _known_ to cause UB.
SmallPtrSet<Instruction *, 8> KnownUBInsts;
private:
/// A set of all the (live) instructions that are assumed to _not_ cause UB.
SmallPtrSet<Instruction *, 8> AssumedNoUBInsts;
// Should be called on updates in which if we're processing an instruction
// \p I that depends on a value \p V, one of the following has to happen:
// - If the value is assumed, then stop.
// - If the value is known but undef, then consider it UB.
// - Otherwise, do specific processing with the simplified value.
// We return None in the first 2 cases to signify that an appropriate
// action was taken and the caller should stop.
// Otherwise, we return the simplified value that the caller should
// use for specific processing.
Optional<Value *> stopOnUndefOrAssumed(Attributor &A, const Value *V,
Instruction *I) {
const auto &ValueSimplifyAA =
A.getAAFor<AAValueSimplify>(*this, IRPosition::value(*V));
Optional<Value *> SimplifiedV =
ValueSimplifyAA.getAssumedSimplifiedValue(A);
if (!ValueSimplifyAA.isKnown()) {
// Don't depend on assumed values.
return llvm::None;
}
if (!SimplifiedV.hasValue()) {
// If it is known (which we tested above) but it doesn't have a value,
// then we can assume `undef` and hence the instruction is UB.
KnownUBInsts.insert(I);
return llvm::None;
}
Value *Val = SimplifiedV.getValue();
if (isa<UndefValue>(Val)) {
KnownUBInsts.insert(I);
return llvm::None;
}
return Val;
}
};
struct AAUndefinedBehaviorFunction final : AAUndefinedBehaviorImpl {
AAUndefinedBehaviorFunction(const IRPosition &IRP)
: AAUndefinedBehaviorImpl(IRP) {}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override {
STATS_DECL(UndefinedBehaviorInstruction, Instruction,
"Number of instructions known to have UB");
BUILD_STAT_NAME(UndefinedBehaviorInstruction, Instruction) +=
KnownUBInsts.size();
}
};
/// ------------------------ Will-Return Attributes ----------------------------
// Helper function that checks whether a function has any cycle.
// TODO: Replace with more efficent code
static bool containsCycle(Function &F) {
SmallPtrSet<BasicBlock *, 32> Visited;
// Traverse BB by dfs and check whether successor is already visited.
for (BasicBlock *BB : depth_first(&F)) {
Visited.insert(BB);
for (auto *SuccBB : successors(BB)) {
if (Visited.count(SuccBB))
return true;
}
}
return false;
}
// Helper function that checks the function have a loop which might become an
// endless loop
// FIXME: Any cycle is regarded as endless loop for now.
// We have to allow some patterns.
static bool containsPossiblyEndlessLoop(Function *F) {
return !F || !F->hasExactDefinition() || containsCycle(*F);
}
struct AAWillReturnImpl : public AAWillReturn {
AAWillReturnImpl(const IRPosition &IRP) : AAWillReturn(IRP) {}
/// See AbstractAttribute::initialize(...).
void initialize(Attributor &A) override {
AAWillReturn::initialize(A);
Function *F = getAssociatedFunction();
if (containsPossiblyEndlessLoop(F))
indicatePessimisticFixpoint();
}
/// See AbstractAttribute::updateImpl(...).
ChangeStatus updateImpl(Attributor &A) override {
auto CheckForWillReturn = [&](Instruction &I) {
IRPosition IPos = IRPosition::callsite_function(ImmutableCallSite(&I));
const auto &WillReturnAA = A.getAAFor<AAWillReturn>(*this, IPos);
if (WillReturnAA.isKnownWillReturn())
return true;
if (!WillReturnAA.isAssumedWillReturn())
return false;
const auto &NoRecurseAA = A.getAAFor<AANoRecurse>(*this, IPos);
return NoRecurseAA.isAssumedNoRecurse();
};
if (!A.checkForAllCallLikeInstructions(CheckForWillReturn, *this))
return indicatePessimisticFixpoint();
return ChangeStatus::UNCHANGED;
}
/// See AbstractAttribute::getAsStr()
const std::string getAsStr() const override {
return getAssumed() ? "willreturn" : "may-noreturn";
}
};
struct AAWillReturnFunction final : AAWillReturnImpl {
AAWillReturnFunction(const IRPosition &IRP) : AAWillReturnImpl(IRP) {}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override { STATS_DECLTRACK_FN_ATTR(willreturn) }
};
/// WillReturn attribute deduction for a call sites.
struct AAWillReturnCallSite final : AAWillReturnImpl {
AAWillReturnCallSite(const IRPosition &IRP) : AAWillReturnImpl(IRP) {}
/// See AbstractAttribute::initialize(...).
void initialize(Attributor &A) override {
AAWillReturnImpl::initialize(A);
Function *F = getAssociatedFunction();
if (!F)
indicatePessimisticFixpoint();
}
/// See AbstractAttribute::updateImpl(...).
ChangeStatus updateImpl(Attributor &A) override {
// TODO: Once we have call site specific value information we can provide
// call site specific liveness information and then it makes
// sense to specialize attributes for call sites arguments instead of
// redirecting requests to the callee argument.
Function *F = getAssociatedFunction();
const IRPosition &FnPos = IRPosition::function(*F);
auto &FnAA = A.getAAFor<AAWillReturn>(*this, FnPos);
return clampStateAndIndicateChange(
getState(),
static_cast<const AAWillReturn::StateType &>(FnAA.getState()));
}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override { STATS_DECLTRACK_CS_ATTR(willreturn); }
};
/// -------------------AAReachability Attribute--------------------------
struct AAReachabilityImpl : AAReachability {
AAReachabilityImpl(const IRPosition &IRP) : AAReachability(IRP) {}
const std::string getAsStr() const override {
// TODO: Return the number of reachable queries.
return "reachable";
}
/// See AbstractAttribute::initialize(...).
void initialize(Attributor &A) override { indicatePessimisticFixpoint(); }
/// See AbstractAttribute::updateImpl(...).
ChangeStatus updateImpl(Attributor &A) override {
return indicatePessimisticFixpoint();
}
};
struct AAReachabilityFunction final : public AAReachabilityImpl {
AAReachabilityFunction(const IRPosition &IRP) : AAReachabilityImpl(IRP) {}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override { STATS_DECLTRACK_FN_ATTR(reachable); }
};
/// ------------------------ NoAlias Argument Attribute ------------------------
struct AANoAliasImpl : AANoAlias {
AANoAliasImpl(const IRPosition &IRP) : AANoAlias(IRP) {}
const std::string getAsStr() const override {
return getAssumed() ? "noalias" : "may-alias";
}
};
/// NoAlias attribute for a floating value.
struct AANoAliasFloating final : AANoAliasImpl {
AANoAliasFloating(const IRPosition &IRP) : AANoAliasImpl(IRP) {}
/// See AbstractAttribute::initialize(...).
void initialize(Attributor &A) override {
AANoAliasImpl::initialize(A);
Value &Val = getAssociatedValue();
if (isa<AllocaInst>(Val))
indicateOptimisticFixpoint();
if (isa<ConstantPointerNull>(Val) &&
Val.getType()->getPointerAddressSpace() == 0)
indicateOptimisticFixpoint();
}
/// See AbstractAttribute::updateImpl(...).
ChangeStatus updateImpl(Attributor &A) override {
// TODO: Implement this.
return indicatePessimisticFixpoint();
}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override {
STATS_DECLTRACK_FLOATING_ATTR(noalias)
}
};
/// NoAlias attribute for an argument.
struct AANoAliasArgument final
: AAArgumentFromCallSiteArguments<AANoAlias, AANoAliasImpl> {
using Base = AAArgumentFromCallSiteArguments<AANoAlias, AANoAliasImpl>;
AANoAliasArgument(const IRPosition &IRP) : Base(IRP) {}
/// See AbstractAttribute::update(...).
ChangeStatus updateImpl(Attributor &A) override {
// We have to make sure no-alias on the argument does not break
// synchronization when this is a callback argument, see also [1] below.
// If synchronization cannot be affected, we delegate to the base updateImpl
// function, otherwise we give up for now.
// If the function is no-sync, no-alias cannot break synchronization.
const auto &NoSyncAA = A.getAAFor<AANoSync>(
*this, IRPosition::function_scope(getIRPosition()));
if (NoSyncAA.isAssumedNoSync())
return Base::updateImpl(A);
// If the argument is read-only, no-alias cannot break synchronization.
const auto &MemBehaviorAA =
A.getAAFor<AAMemoryBehavior>(*this, getIRPosition());
if (MemBehaviorAA.isAssumedReadOnly())
return Base::updateImpl(A);
// If the argument is never passed through callbacks, no-alias cannot break
// synchronization.
if (A.checkForAllCallSites(
[](AbstractCallSite ACS) { return !ACS.isCallbackCall(); }, *this,
true))
return Base::updateImpl(A);
// TODO: add no-alias but make sure it doesn't break synchronization by
// introducing fake uses. See:
// [1] Compiler Optimizations for OpenMP, J. Doerfert and H. Finkel,
// International Workshop on OpenMP 2018,
// http://compilers.cs.uni-saarland.de/people/doerfert/par_opt18.pdf
return indicatePessimisticFixpoint();
}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override { STATS_DECLTRACK_ARG_ATTR(noalias) }
};
struct AANoAliasCallSiteArgument final : AANoAliasImpl {
AANoAliasCallSiteArgument(const IRPosition &IRP) : AANoAliasImpl(IRP) {}
/// See AbstractAttribute::initialize(...).
void initialize(Attributor &A) override {
// See callsite argument attribute and callee argument attribute.
ImmutableCallSite ICS(&getAnchorValue());
if (ICS.paramHasAttr(getArgNo(), Attribute::NoAlias))
indicateOptimisticFixpoint();
}
/// See AbstractAttribute::updateImpl(...).
ChangeStatus updateImpl(Attributor &A) override {
// We can deduce "noalias" if the following conditions hold.
// (i) Associated value is assumed to be noalias in the definition.
// (ii) Associated value is assumed to be no-capture in all the uses
// possibly executed before this callsite.
// (iii) There is no other pointer argument which could alias with the
// value.
const Value &V = getAssociatedValue();
const IRPosition IRP = IRPosition::value(V);
// (i) Check whether noalias holds in the definition.
auto &NoAliasAA = A.getAAFor<AANoAlias>(*this, IRP);
LLVM_DEBUG(dbgs() << "[Attributor][AANoAliasCSArg] check definition: " << V
<< " :: " << NoAliasAA << "\n");
if (!NoAliasAA.isAssumedNoAlias())
return indicatePessimisticFixpoint();
LLVM_DEBUG(dbgs() << "[Attributor][AANoAliasCSArg] " << V
<< " is assumed NoAlias in the definition\n");
// (ii) Check whether the value is captured in the scope using AANoCapture.
// FIXME: This is conservative though, it is better to look at CFG and
// check only uses possibly executed before this callsite.
auto &NoCaptureAA = A.getAAFor<AANoCapture>(*this, IRP);
if (!NoCaptureAA.isAssumedNoCaptureMaybeReturned()) {
LLVM_DEBUG(
dbgs() << "[Attributor][AANoAliasCSArg] " << V
<< " cannot be noalias as it is potentially captured\n");
return indicatePessimisticFixpoint();
}
// (iii) Check there is no other pointer argument which could alias with the
// value.
// TODO: AbstractCallSite
ImmutableCallSite ICS(&getAnchorValue());
for (unsigned i = 0; i < ICS.getNumArgOperands(); i++) {
if (getArgNo() == (int)i)
continue;
const Value *ArgOp = ICS.getArgOperand(i);
if (!ArgOp->getType()->isPointerTy())
continue;
if (const Function *F = getAnchorScope()) {
if (AAResults *AAR = A.getInfoCache().getAAResultsForFunction(*F)) {
bool IsAliasing = !AAR->isNoAlias(&getAssociatedValue(), ArgOp);
LLVM_DEBUG(dbgs()
<< "[Attributor][NoAliasCSArg] Check alias between "
"callsite arguments "
<< AAR->isNoAlias(&getAssociatedValue(), ArgOp) << " "
<< getAssociatedValue() << " " << *ArgOp << " => "
<< (IsAliasing ? "" : "no-") << "alias \n");
if (!IsAliasing)
continue;
}
}
return indicatePessimisticFixpoint();
}
return ChangeStatus::UNCHANGED;
}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override { STATS_DECLTRACK_CSARG_ATTR(noalias) }
};
/// NoAlias attribute for function return value.
struct AANoAliasReturned final : AANoAliasImpl {
AANoAliasReturned(const IRPosition &IRP) : AANoAliasImpl(IRP) {}
/// See AbstractAttribute::updateImpl(...).
virtual ChangeStatus updateImpl(Attributor &A) override {
auto CheckReturnValue = [&](Value &RV) -> bool {
if (Constant *C = dyn_cast<Constant>(&RV))
if (C->isNullValue() || isa<UndefValue>(C))
return true;
/// For now, we can only deduce noalias if we have call sites.
/// FIXME: add more support.
ImmutableCallSite ICS(&RV);
if (!ICS)
return false;
const IRPosition &RVPos = IRPosition::value(RV);
const auto &NoAliasAA = A.getAAFor<AANoAlias>(*this, RVPos);
if (!NoAliasAA.isAssumedNoAlias())
return false;
const auto &NoCaptureAA = A.getAAFor<AANoCapture>(*this, RVPos);
return NoCaptureAA.isAssumedNoCaptureMaybeReturned();
};
if (!A.checkForAllReturnedValues(CheckReturnValue, *this))
return indicatePessimisticFixpoint();
return ChangeStatus::UNCHANGED;
}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override { STATS_DECLTRACK_FNRET_ATTR(noalias) }
};
/// NoAlias attribute deduction for a call site return value.
struct AANoAliasCallSiteReturned final : AANoAliasImpl {
AANoAliasCallSiteReturned(const IRPosition &IRP) : AANoAliasImpl(IRP) {}
/// See AbstractAttribute::initialize(...).
void initialize(Attributor &A) override {
AANoAliasImpl::initialize(A);
Function *F = getAssociatedFunction();
if (!F)
indicatePessimisticFixpoint();
}
/// See AbstractAttribute::updateImpl(...).
ChangeStatus updateImpl(Attributor &A) override {
// TODO: Once we have call site specific value information we can provide
// call site specific liveness information and then it makes
// sense to specialize attributes for call sites arguments instead of
// redirecting requests to the callee argument.
Function *F = getAssociatedFunction();
const IRPosition &FnPos = IRPosition::returned(*F);
auto &FnAA = A.getAAFor<AANoAlias>(*this, FnPos);
return clampStateAndIndicateChange(
getState(), static_cast<const AANoAlias::StateType &>(FnAA.getState()));
}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override { STATS_DECLTRACK_CSRET_ATTR(noalias); }
};
/// -------------------AAIsDead Function Attribute-----------------------
struct AAIsDeadValueImpl : public AAIsDead {
AAIsDeadValueImpl(const IRPosition &IRP) : AAIsDead(IRP) {}
/// See AAIsDead::isAssumedDead().
bool isAssumedDead() const override { return getAssumed(); }
/// See AAIsDead::isAssumedDead(BasicBlock *).
bool isAssumedDead(const BasicBlock *BB) const override { return false; }
/// See AAIsDead::isKnownDead(BasicBlock *).
bool isKnownDead(const BasicBlock *BB) const override { return false; }
/// See AAIsDead::isAssumedDead(Instruction *I).
bool isAssumedDead(const Instruction *I) const override {
return I == getCtxI() && isAssumedDead();
}
/// See AAIsDead::isKnownDead(Instruction *I).
bool isKnownDead(const Instruction *I) const override {
return I == getCtxI() && getKnown();
}
/// See AbstractAttribute::getAsStr().
const std::string getAsStr() const override {
return isAssumedDead() ? "assumed-dead" : "assumed-live";
}
};
struct AAIsDeadFloating : public AAIsDeadValueImpl {
AAIsDeadFloating(const IRPosition &IRP) : AAIsDeadValueImpl(IRP) {}
/// See AbstractAttribute::initialize(...).
void initialize(Attributor &A) override {
if (Instruction *I = dyn_cast<Instruction>(&getAssociatedValue()))
if (!wouldInstructionBeTriviallyDead(I))
indicatePessimisticFixpoint();
if (isa<UndefValue>(getAssociatedValue()))
indicatePessimisticFixpoint();
}
/// See AbstractAttribute::updateImpl(...).
ChangeStatus updateImpl(Attributor &A) override {
auto UsePred = [&](const Use &U, bool &Follow) {
Instruction *UserI = cast<Instruction>(U.getUser());
if (CallSite CS = CallSite(UserI)) {
if (!CS.isArgOperand(&U))
return false;
const IRPosition &CSArgPos =
IRPosition::callsite_argument(CS, CS.getArgumentNo(&U));
const auto &CSArgIsDead = A.getAAFor<AAIsDead>(*this, CSArgPos);
return CSArgIsDead.isAssumedDead();
}
if (ReturnInst *RI = dyn_cast<ReturnInst>(UserI)) {
const IRPosition &RetPos = IRPosition::returned(*RI->getFunction());
const auto &RetIsDeadAA = A.getAAFor<AAIsDead>(*this, RetPos);
return RetIsDeadAA.isAssumedDead();
}
Follow = true;
return wouldInstructionBeTriviallyDead(UserI);
};
if (!A.checkForAllUses(UsePred, *this, getAssociatedValue()))
return indicatePessimisticFixpoint();
return ChangeStatus::UNCHANGED;
}
/// See AbstractAttribute::manifest(...).
ChangeStatus manifest(Attributor &A) override {
Value &V = getAssociatedValue();
if (auto *I = dyn_cast<Instruction>(&V))
if (wouldInstructionBeTriviallyDead(I)) {
A.deleteAfterManifest(*I);
return ChangeStatus::CHANGED;
}
if (V.use_empty())
return ChangeStatus::UNCHANGED;
UndefValue &UV = *UndefValue::get(V.getType());
bool AnyChange = A.changeValueAfterManifest(V, UV);
return AnyChange ? ChangeStatus::CHANGED : ChangeStatus::UNCHANGED;
}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override {
STATS_DECLTRACK_FLOATING_ATTR(IsDead)
}
};
struct AAIsDeadArgument : public AAIsDeadFloating {
AAIsDeadArgument(const IRPosition &IRP) : AAIsDeadFloating(IRP) {}
/// See AbstractAttribute::initialize(...).
void initialize(Attributor &A) override {
if (!getAssociatedFunction()->hasExactDefinition())
indicatePessimisticFixpoint();
}
/// See AbstractAttribute::manifest(...).
ChangeStatus manifest(Attributor &A) override {
ChangeStatus Changed = AAIsDeadFloating::manifest(A);
Argument &Arg = *getAssociatedArgument();
if (Arg.getParent()->hasLocalLinkage())
if (A.registerFunctionSignatureRewrite(
Arg, /* ReplacementTypes */ {},
Attributor::ArgumentReplacementInfo::CalleeRepairCBTy{},
Attributor::ArgumentReplacementInfo::ACSRepairCBTy{}))
return ChangeStatus::CHANGED;
return Changed;
}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override { STATS_DECLTRACK_ARG_ATTR(IsDead) }
};
struct AAIsDeadCallSiteArgument : public AAIsDeadValueImpl {
AAIsDeadCallSiteArgument(const IRPosition &IRP) : AAIsDeadValueImpl(IRP) {}
/// See AbstractAttribute::initialize(...).
void initialize(Attributor &A) override {
if (isa<UndefValue>(getAssociatedValue()))
indicatePessimisticFixpoint();
}
/// See AbstractAttribute::updateImpl(...).
ChangeStatus updateImpl(Attributor &A) override {
// TODO: Once we have call site specific value information we can provide
// call site specific liveness information and then it makes
// sense to specialize attributes for call sites arguments instead of
// redirecting requests to the callee argument.
Argument *Arg = getAssociatedArgument();
if (!Arg)
return indicatePessimisticFixpoint();
const IRPosition &ArgPos = IRPosition::argument(*Arg);
auto &ArgAA = A.getAAFor<AAIsDead>(*this, ArgPos);
return clampStateAndIndicateChange(
getState(), static_cast<const AAIsDead::StateType &>(ArgAA.getState()));
}
/// See AbstractAttribute::manifest(...).
ChangeStatus manifest(Attributor &A) override {
CallBase &CB = cast<CallBase>(getAnchorValue());
Use &U = CB.getArgOperandUse(getArgNo());
assert(!isa<UndefValue>(U.get()) &&
"Expected undef values to be filtered out!");
UndefValue &UV = *UndefValue::get(U->getType());
if (A.changeUseAfterManifest(U, UV))
return ChangeStatus::CHANGED;
return ChangeStatus::UNCHANGED;
}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override { STATS_DECLTRACK_CSARG_ATTR(IsDead) }
};
struct AAIsDeadReturned : public AAIsDeadValueImpl {
AAIsDeadReturned(const IRPosition &IRP) : AAIsDeadValueImpl(IRP) {}
/// See AbstractAttribute::updateImpl(...).
ChangeStatus updateImpl(Attributor &A) override {
auto PredForCallSite = [&](AbstractCallSite ACS) {
if (ACS.isCallbackCall())
return false;
const IRPosition &CSRetPos =
IRPosition::callsite_returned(ACS.getCallSite());
const auto &RetIsDeadAA = A.getAAFor<AAIsDead>(*this, CSRetPos);
return RetIsDeadAA.isAssumedDead();
};
if (!A.checkForAllCallSites(PredForCallSite, *this, true))
return indicatePessimisticFixpoint();
return ChangeStatus::UNCHANGED;
}
/// See AbstractAttribute::manifest(...).
ChangeStatus manifest(Attributor &A) override {
// TODO: Rewrite the signature to return void?
bool AnyChange = false;
UndefValue &UV = *UndefValue::get(getAssociatedFunction()->getReturnType());
auto RetInstPred = [&](Instruction &I) {
ReturnInst &RI = cast<ReturnInst>(I);
if (!isa<UndefValue>(RI.getReturnValue()))
AnyChange |= A.changeUseAfterManifest(RI.getOperandUse(0), UV);
return true;
};
A.checkForAllInstructions(RetInstPred, *this, {Instruction::Ret});
return AnyChange ? ChangeStatus::CHANGED : ChangeStatus::UNCHANGED;
}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override { STATS_DECLTRACK_FNRET_ATTR(IsDead) }
};
struct AAIsDeadCallSiteReturned : public AAIsDeadFloating {
AAIsDeadCallSiteReturned(const IRPosition &IRP) : AAIsDeadFloating(IRP) {}
/// See AbstractAttribute::initialize(...).
void initialize(Attributor &A) override {}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override { STATS_DECLTRACK_CSRET_ATTR(IsDead) }
};
struct AAIsDeadFunction : public AAIsDead {
AAIsDeadFunction(const IRPosition &IRP) : AAIsDead(IRP) {}
/// See AbstractAttribute::initialize(...).
void initialize(Attributor &A) override {
const Function *F = getAssociatedFunction();
if (F && !F->isDeclaration()) {
ToBeExploredFrom.insert(&F->getEntryBlock().front());
assumeLive(A, F->getEntryBlock());
}
}
/// See AbstractAttribute::getAsStr().
const std::string getAsStr() const override {
return "Live[#BB " + std::to_string(AssumedLiveBlocks.size()) + "/" +
std::to_string(getAssociatedFunction()->size()) + "][#TBEP " +
std::to_string(ToBeExploredFrom.size()) + "][#KDE " +
std::to_string(KnownDeadEnds.size()) + "]";
}
/// See AbstractAttribute::manifest(...).
ChangeStatus manifest(Attributor &A) override {
assert(getState().isValidState() &&
"Attempted to manifest an invalid state!");
ChangeStatus HasChanged = ChangeStatus::UNCHANGED;
Function &F = *getAssociatedFunction();
if (AssumedLiveBlocks.empty()) {
A.deleteAfterManifest(F);
return ChangeStatus::CHANGED;
}
// Flag to determine if we can change an invoke to a call assuming the
// callee is nounwind. This is not possible if the personality of the
// function allows to catch asynchronous exceptions.
bool Invoke2CallAllowed = !mayCatchAsynchronousExceptions(F);
KnownDeadEnds.set_union(ToBeExploredFrom);
for (const Instruction *DeadEndI : KnownDeadEnds) {
auto *CB = dyn_cast<CallBase>(DeadEndI);
if (!CB)
continue;
const auto &NoReturnAA =
A.getAAFor<AANoReturn>(*this, IRPosition::callsite_function(*CB));
bool MayReturn = !NoReturnAA.isAssumedNoReturn();
if (MayReturn && (!Invoke2CallAllowed || !isa<InvokeInst>(CB)))
continue;
Instruction *I = const_cast<Instruction *>(DeadEndI);
BasicBlock *BB = I->getParent();
Instruction *SplitPos = I->getNextNode();
// TODO: mark stuff before unreachable instructions as dead.
if (auto *II = dyn_cast<InvokeInst>(I)) {
// If we keep the invoke the split position is at the beginning of the
// normal desitination block (it invokes a noreturn function after all).
BasicBlock *NormalDestBB = II->getNormalDest();
SplitPos = &NormalDestBB->front();
/// Invoke is replaced with a call and unreachable is placed after it if
/// the callee is nounwind and noreturn. Otherwise, we keep the invoke
/// and only place an unreachable in the normal successor.
if (Invoke2CallAllowed) {
if (II->getCalledFunction()) {
const IRPosition &IPos = IRPosition::callsite_function(*II);
const auto &AANoUnw = A.getAAFor<AANoUnwind>(*this, IPos);
if (AANoUnw.isAssumedNoUnwind()) {
LLVM_DEBUG(dbgs()
<< "[AAIsDead] Replace invoke with call inst\n");
CallInst *CI = createCallMatchingInvoke(II);
CI->insertBefore(II);
CI->takeName(II);
replaceAllInstructionUsesWith(*II, *CI);
// If this is a nounwind + mayreturn invoke we only remove the
// unwind edge. This is done by moving the invoke into a new and
// dead block and connecting the normal destination of the invoke
// with a branch that follows the call replacement we created
// above.
if (MayReturn) {
BasicBlock *NewDeadBB =
SplitBlock(BB, II, nullptr, nullptr, nullptr, ".i2c");
assert(isa<BranchInst>(BB->getTerminator()) &&
BB->getTerminator()->getNumSuccessors() == 1 &&
BB->getTerminator()->getSuccessor(0) == NewDeadBB);
new UnreachableInst(I->getContext(), NewDeadBB);
BB->getTerminator()->setOperand(0, NormalDestBB);
A.deleteAfterManifest(*II);
continue;
}
// We do not need an invoke (II) but instead want a call followed
// by an unreachable. However, we do not remove II as other
// abstract attributes might have it cached as part of their
// results. Given that we modify the CFG anyway, we simply keep II
// around but in a new dead block. To avoid II being live through
// a different edge we have to ensure the block we place it in is
// only reached from the current block of II and then not reached
// at all when we insert the unreachable.
SplitBlockPredecessors(NormalDestBB, {BB}, ".i2c");
SplitPos = CI->getNextNode();
}
}
}
if (SplitPos == &NormalDestBB->front()) {
// If this is an invoke of a noreturn function the edge to the normal
// destination block is dead but not necessarily the block itself.
// TODO: We need to move to an edge based system during deduction and
// also manifest.
assert(!NormalDestBB->isLandingPad() &&
"Expected the normal destination not to be a landingpad!");
if (NormalDestBB->getUniquePredecessor() == BB) {
assumeLive(A, *NormalDestBB);
} else {
BasicBlock *SplitBB =
SplitBlockPredecessors(NormalDestBB, {BB}, ".dead");
// The split block is live even if it contains only an unreachable
// instruction at the end.
assumeLive(A, *SplitBB);
SplitPos = SplitBB->getTerminator();
HasChanged = ChangeStatus::CHANGED;
}
}
}
if (isa_and_nonnull<UnreachableInst>(SplitPos))
continue;
BB = SplitPos->getParent();
SplitBlock(BB, SplitPos);
A.changeToUnreachableAfterManifest(BB->getTerminator());
HasChanged = ChangeStatus::CHANGED;
}
for (BasicBlock &BB : F)
if (!AssumedLiveBlocks.count(&BB))
A.deleteAfterManifest(BB);
return HasChanged;
}
/// See AbstractAttribute::updateImpl(...).
ChangeStatus updateImpl(Attributor &A) override;
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override {}
/// Returns true if the function is assumed dead.
bool isAssumedDead() const override { return false; }
/// See AAIsDead::isAssumedDead(BasicBlock *).
bool isAssumedDead(const BasicBlock *BB) const override {
assert(BB->getParent() == getAssociatedFunction() &&
"BB must be in the same anchor scope function.");
if (!getAssumed())
return false;
return !AssumedLiveBlocks.count(BB);
}
/// See AAIsDead::isKnownDead(BasicBlock *).
bool isKnownDead(const BasicBlock *BB) const override {
return getKnown() && isAssumedDead(BB);
}
/// See AAIsDead::isAssumed(Instruction *I).
bool isAssumedDead(const Instruction *I) const override {
assert(I->getParent()->getParent() == getAssociatedFunction() &&
"Instruction must be in the same anchor scope function.");
if (!getAssumed())
return false;
// If it is not in AssumedLiveBlocks then it for sure dead.
// Otherwise, it can still be after noreturn call in a live block.
if (!AssumedLiveBlocks.count(I->getParent()))
return true;
// If it is not after a liveness barrier it is live.
const Instruction *PrevI = I->getPrevNode();
while (PrevI) {
if (KnownDeadEnds.count(PrevI) || ToBeExploredFrom.count(PrevI))
return true;
PrevI = PrevI->getPrevNode();
}
return false;
}
/// See AAIsDead::isKnownDead(Instruction *I).
bool isKnownDead(const Instruction *I) const override {
return getKnown() && isAssumedDead(I);
}
/// Determine if \p F might catch asynchronous exceptions.
static bool mayCatchAsynchronousExceptions(const Function &F) {
return F.hasPersonalityFn() && !canSimplifyInvokeNoUnwind(&F);
}
/// Assume \p BB is (partially) live now and indicate to the Attributor \p A
/// that internal function called from \p BB should now be looked at.
bool assumeLive(Attributor &A, const BasicBlock &BB) {
if (!AssumedLiveBlocks.insert(&BB).second)
return false;
// We assume that all of BB is (probably) live now and if there are calls to
// internal functions we will assume that those are now live as well. This
// is a performance optimization for blocks with calls to a lot of internal
// functions. It can however cause dead functions to be treated as live.
for (const Instruction &I : BB)
if (ImmutableCallSite ICS = ImmutableCallSite(&I))
if (const Function *F = ICS.getCalledFunction())
if (F->hasLocalLinkage())
A.markLiveInternalFunction(*F);
return true;
}
/// Collection of instructions that need to be explored again, e.g., we
/// did assume they do not transfer control to (one of their) successors.
SmallSetVector<const Instruction *, 8> ToBeExploredFrom;
/// Collection of instructions that are known to not transfer control.
SmallSetVector<const Instruction *, 8> KnownDeadEnds;
/// Collection of all assumed live BasicBlocks.
DenseSet<const BasicBlock *> AssumedLiveBlocks;
};
static bool
identifyAliveSuccessors(Attributor &A, const CallBase &CB,
AbstractAttribute &AA,
SmallVectorImpl<const Instruction *> &AliveSuccessors) {
const IRPosition &IPos = IRPosition::callsite_function(CB);
const auto &NoReturnAA = A.getAAFor<AANoReturn>(AA, IPos);
if (NoReturnAA.isAssumedNoReturn())
return !NoReturnAA.isKnownNoReturn();
if (CB.isTerminator())
AliveSuccessors.push_back(&CB.getSuccessor(0)->front());
else
AliveSuccessors.push_back(CB.getNextNode());
return false;
}
static bool
identifyAliveSuccessors(Attributor &A, const InvokeInst &II,
AbstractAttribute &AA,
SmallVectorImpl<const Instruction *> &AliveSuccessors) {
bool UsedAssumedInformation =
identifyAliveSuccessors(A, cast<CallBase>(II), AA, AliveSuccessors);
// First, determine if we can change an invoke to a call assuming the
// callee is nounwind. This is not possible if the personality of the
// function allows to catch asynchronous exceptions.
if (AAIsDeadFunction::mayCatchAsynchronousExceptions(*II.getFunction())) {
AliveSuccessors.push_back(&II.getUnwindDest()->front());
} else {
const IRPosition &IPos = IRPosition::callsite_function(II);
const auto &AANoUnw = A.getAAFor<AANoUnwind>(AA, IPos);
if (AANoUnw.isAssumedNoUnwind()) {
UsedAssumedInformation |= !AANoUnw.isKnownNoUnwind();
} else {
AliveSuccessors.push_back(&II.getUnwindDest()->front());
}
}
return UsedAssumedInformation;
}
static Optional<ConstantInt *>
getAssumedConstant(Attributor &A, const Value &V, AbstractAttribute &AA,
bool &UsedAssumedInformation) {
const auto &ValueSimplifyAA =
A.getAAFor<AAValueSimplify>(AA, IRPosition::value(V));
Optional<Value *> SimplifiedV = ValueSimplifyAA.getAssumedSimplifiedValue(A);
UsedAssumedInformation |= !ValueSimplifyAA.isKnown();
if (!SimplifiedV.hasValue())
return llvm::None;
if (isa_and_nonnull<UndefValue>(SimplifiedV.getValue()))
return llvm::None;
return dyn_cast_or_null<ConstantInt>(SimplifiedV.getValue());
}
static bool
identifyAliveSuccessors(Attributor &A, const BranchInst &BI,
AbstractAttribute &AA,
SmallVectorImpl<const Instruction *> &AliveSuccessors) {
bool UsedAssumedInformation = false;
if (BI.getNumSuccessors() == 1) {
AliveSuccessors.push_back(&BI.getSuccessor(0)->front());
} else {
Optional<ConstantInt *> CI =
getAssumedConstant(A, *BI.getCondition(), AA, UsedAssumedInformation);
if (!CI.hasValue()) {
// No value yet, assume both edges are dead.
} else if (CI.getValue()) {
const BasicBlock *SuccBB =
BI.getSuccessor(1 - CI.getValue()->getZExtValue());
AliveSuccessors.push_back(&SuccBB->front());
} else {
AliveSuccessors.push_back(&BI.getSuccessor(0)->front());
AliveSuccessors.push_back(&BI.getSuccessor(1)->front());
UsedAssumedInformation = false;
}
}
return UsedAssumedInformation;
}
static bool
identifyAliveSuccessors(Attributor &A, const SwitchInst &SI,
AbstractAttribute &AA,
SmallVectorImpl<const Instruction *> &AliveSuccessors) {
bool UsedAssumedInformation = false;
Optional<ConstantInt *> CI =
getAssumedConstant(A, *SI.getCondition(), AA, UsedAssumedInformation);
if (!CI.hasValue()) {
// No value yet, assume all edges are dead.
} else if (CI.getValue()) {
for (auto &CaseIt : SI.cases()) {
if (CaseIt.getCaseValue() == CI.getValue()) {
AliveSuccessors.push_back(&CaseIt.getCaseSuccessor()->front());
return UsedAssumedInformation;
}
}
AliveSuccessors.push_back(&SI.getDefaultDest()->front());
return UsedAssumedInformation;
} else {
for (const BasicBlock *SuccBB : successors(SI.getParent()))
AliveSuccessors.push_back(&SuccBB->front());
}
return UsedAssumedInformation;
}
ChangeStatus AAIsDeadFunction::updateImpl(Attributor &A) {
ChangeStatus Change = ChangeStatus::UNCHANGED;
LLVM_DEBUG(dbgs() << "[AAIsDead] Live [" << AssumedLiveBlocks.size() << "/"
<< getAssociatedFunction()->size() << "] BBs and "
<< ToBeExploredFrom.size() << " exploration points and "
<< KnownDeadEnds.size() << " known dead ends\n");
// Copy and clear the list of instructions we need to explore from. It is
// refilled with instructions the next update has to look at.
SmallVector<const Instruction *, 8> Worklist(ToBeExploredFrom.begin(),
ToBeExploredFrom.end());
decltype(ToBeExploredFrom) NewToBeExploredFrom;
SmallVector<const Instruction *, 8> AliveSuccessors;
while (!Worklist.empty()) {
const Instruction *I = Worklist.pop_back_val();
LLVM_DEBUG(dbgs() << "[AAIsDead] Exploration inst: " << *I << "\n");
AliveSuccessors.clear();
bool UsedAssumedInformation = false;
switch (I->getOpcode()) {
// TODO: look for (assumed) UB to backwards propagate "deadness".
default:
if (I->isTerminator()) {
for (const BasicBlock *SuccBB : successors(I->getParent()))
AliveSuccessors.push_back(&SuccBB->front());
} else {
AliveSuccessors.push_back(I->getNextNode());
}
break;
case Instruction::Call:
UsedAssumedInformation = identifyAliveSuccessors(A, cast<CallInst>(*I),
*this, AliveSuccessors);
break;
case Instruction::Invoke:
UsedAssumedInformation = identifyAliveSuccessors(A, cast<InvokeInst>(*I),
*this, AliveSuccessors);
break;
case Instruction::Br:
UsedAssumedInformation = identifyAliveSuccessors(A, cast<BranchInst>(*I),
*this, AliveSuccessors);
break;
case Instruction::Switch:
UsedAssumedInformation = identifyAliveSuccessors(A, cast<SwitchInst>(*I),
*this, AliveSuccessors);
break;
}
if (UsedAssumedInformation) {
NewToBeExploredFrom.insert(I);
} else {
Change = ChangeStatus::CHANGED;
if (AliveSuccessors.empty() ||
(I->isTerminator() && AliveSuccessors.size() < I->getNumSuccessors()))
KnownDeadEnds.insert(I);
}
LLVM_DEBUG(dbgs() << "[AAIsDead] #AliveSuccessors: "
<< AliveSuccessors.size() << " UsedAssumedInformation: "
<< UsedAssumedInformation << "\n");
for (const Instruction *AliveSuccessor : AliveSuccessors) {
if (!I->isTerminator()) {
assert(AliveSuccessors.size() == 1 &&
"Non-terminator expected to have a single successor!");
Worklist.push_back(AliveSuccessor);
} else {
if (assumeLive(A, *AliveSuccessor->getParent()))
Worklist.push_back(AliveSuccessor);
}
}
}
ToBeExploredFrom = std::move(NewToBeExploredFrom);
// If we know everything is live there is no need to query for liveness.
// Instead, indicating a pessimistic fixpoint will cause the state to be
// "invalid" and all queries to be answered conservatively without lookups.
// To be in this state we have to (1) finished the exploration and (3) not
// discovered any non-trivial dead end and (2) not ruled unreachable code
// dead.
if (ToBeExploredFrom.empty() &&
getAssociatedFunction()->size() == AssumedLiveBlocks.size() &&
llvm::all_of(KnownDeadEnds, [](const Instruction *DeadEndI) {
return DeadEndI->isTerminator() && DeadEndI->getNumSuccessors() == 0;
}))
return indicatePessimisticFixpoint();
return Change;
}
/// Liveness information for a call sites.
struct AAIsDeadCallSite final : AAIsDeadFunction {
AAIsDeadCallSite(const IRPosition &IRP) : AAIsDeadFunction(IRP) {}
/// See AbstractAttribute::initialize(...).
void initialize(Attributor &A) override {
// TODO: Once we have call site specific value information we can provide
// call site specific liveness information and then it makes
// sense to specialize attributes for call sites instead of
// redirecting requests to the callee.
llvm_unreachable("Abstract attributes for liveness are not "
"supported for call sites yet!");
}
/// See AbstractAttribute::updateImpl(...).
ChangeStatus updateImpl(Attributor &A) override {
return indicatePessimisticFixpoint();
}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override {}
};
/// -------------------- Dereferenceable Argument Attribute --------------------
template <>
ChangeStatus clampStateAndIndicateChange<DerefState>(DerefState &S,
const DerefState &R) {
ChangeStatus CS0 =
clampStateAndIndicateChange(S.DerefBytesState, R.DerefBytesState);
ChangeStatus CS1 = clampStateAndIndicateChange(S.GlobalState, R.GlobalState);
return CS0 | CS1;
}
struct AADereferenceableImpl : AADereferenceable {
AADereferenceableImpl(const IRPosition &IRP) : AADereferenceable(IRP) {}
using StateType = DerefState;
void initialize(Attributor &A) override {
SmallVector<Attribute, 4> Attrs;
getAttrs({Attribute::Dereferenceable, Attribute::DereferenceableOrNull},
Attrs);
for (const Attribute &Attr : Attrs)
takeKnownDerefBytesMaximum(Attr.getValueAsInt());
NonNullAA = &A.getAAFor<AANonNull>(*this, getIRPosition());
const IRPosition &IRP = this->getIRPosition();
bool IsFnInterface = IRP.isFnInterfaceKind();
const Function *FnScope = IRP.getAnchorScope();
if (IsFnInterface && (!FnScope || !FnScope->hasExactDefinition()))
indicatePessimisticFixpoint();
}
/// See AbstractAttribute::getState()
/// {
StateType &getState() override { return *this; }
const StateType &getState() const override { return *this; }
/// }
/// Helper function for collecting accessed bytes in must-be-executed-context
void addAccessedBytesForUse(Attributor &A, const Use *U,
const Instruction *I) {
const Value *UseV = U->get();
if (!UseV->getType()->isPointerTy())
return;
Type *PtrTy = UseV->getType();
const DataLayout &DL = A.getDataLayout();
int64_t Offset;
if (const Value *Base = getBasePointerOfAccessPointerOperand(
I, Offset, DL, /*AllowNonInbounds*/ true)) {
if (Base == &getAssociatedValue() &&
Attributor::getPointerOperand(I, /* AllowVolatile */ false) == UseV) {
uint64_t Size = DL.getTypeStoreSize(PtrTy->getPointerElementType());
addAccessedBytes(Offset, Size);
}
}
return;
}
/// See AAFromMustBeExecutedContext
bool followUse(Attributor &A, const Use *U, const Instruction *I) {
bool IsNonNull = false;
bool TrackUse = false;
int64_t DerefBytes = getKnownNonNullAndDerefBytesForUse(
A, *this, getAssociatedValue(), U, I, IsNonNull, TrackUse);
addAccessedBytesForUse(A, U, I);
takeKnownDerefBytesMaximum(DerefBytes);
return TrackUse;
}
/// See AbstractAttribute::manifest(...).
ChangeStatus manifest(Attributor &A) override {
ChangeStatus Change = AADereferenceable::manifest(A);
if (isAssumedNonNull() && hasAttr(Attribute::DereferenceableOrNull)) {
removeAttrs({Attribute::DereferenceableOrNull});
return ChangeStatus::CHANGED;
}
return Change;
}
void getDeducedAttributes(LLVMContext &Ctx,
SmallVectorImpl<Attribute> &Attrs) const override {
// TODO: Add *_globally support
if (isAssumedNonNull())
Attrs.emplace_back(Attribute::getWithDereferenceableBytes(
Ctx, getAssumedDereferenceableBytes()));
else
Attrs.emplace_back(Attribute::getWithDereferenceableOrNullBytes(
Ctx, getAssumedDereferenceableBytes()));
}
/// See AbstractAttribute::getAsStr().
const std::string getAsStr() const override {
if (!getAssumedDereferenceableBytes())
return "unknown-dereferenceable";
return std::string("dereferenceable") +
(isAssumedNonNull() ? "" : "_or_null") +
(isAssumedGlobal() ? "_globally" : "") + "<" +
std::to_string(getKnownDereferenceableBytes()) + "-" +
std::to_string(getAssumedDereferenceableBytes()) + ">";
}
};
/// Dereferenceable attribute for a floating value.
struct AADereferenceableFloating
: AAFromMustBeExecutedContext<AADereferenceable, AADereferenceableImpl> {
using Base =
AAFromMustBeExecutedContext<AADereferenceable, AADereferenceableImpl>;
AADereferenceableFloating(const IRPosition &IRP) : Base(IRP) {}
/// See AbstractAttribute::updateImpl(...).
ChangeStatus updateImpl(Attributor &A) override {
ChangeStatus Change = Base::updateImpl(A);
const DataLayout &DL = A.getDataLayout();
auto VisitValueCB = [&](Value &V, DerefState &T, bool Stripped) -> bool {
unsigned IdxWidth =
DL.getIndexSizeInBits(V.getType()->getPointerAddressSpace());
APInt Offset(IdxWidth, 0);
const Value *Base =
V.stripAndAccumulateInBoundsConstantOffsets(DL, Offset);
const auto &AA =
A.getAAFor<AADereferenceable>(*this, IRPosition::value(*Base));
int64_t DerefBytes = 0;
if (!Stripped && this == &AA) {
// Use IR information if we did not strip anything.
// TODO: track globally.
bool CanBeNull;
DerefBytes = Base->getPointerDereferenceableBytes(DL, CanBeNull);
T.GlobalState.indicatePessimisticFixpoint();
} else {
const DerefState &DS = static_cast<const DerefState &>(AA.getState());
DerefBytes = DS.DerefBytesState.getAssumed();
T.GlobalState &= DS.GlobalState;
}
// For now we do not try to "increase" dereferenceability due to negative
// indices as we first have to come up with code to deal with loops and
// for overflows of the dereferenceable bytes.
int64_t OffsetSExt = Offset.getSExtValue();
if (OffsetSExt < 0)
OffsetSExt = 0;
T.takeAssumedDerefBytesMinimum(
std::max(int64_t(0), DerefBytes - OffsetSExt));
if (this == &AA) {
if (!Stripped) {
// If nothing was stripped IR information is all we got.
T.takeKnownDerefBytesMaximum(
std::max(int64_t(0), DerefBytes - OffsetSExt));
T.indicatePessimisticFixpoint();
} else if (OffsetSExt > 0) {
// If something was stripped but there is circular reasoning we look
// for the offset. If it is positive we basically decrease the
// dereferenceable bytes in a circluar loop now, which will simply
// drive them down to the known value in a very slow way which we
// can accelerate.
T.indicatePessimisticFixpoint();
}
}
return T.isValidState();
};
DerefState T;
if (!genericValueTraversal<AADereferenceable, DerefState>(
A, getIRPosition(), *this, T, VisitValueCB))
return indicatePessimisticFixpoint();
return Change | clampStateAndIndicateChange(getState(), T);
}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override {
STATS_DECLTRACK_FLOATING_ATTR(dereferenceable)
}
};
/// Dereferenceable attribute for a return value.
struct AADereferenceableReturned final
: AAReturnedFromReturnedValues<AADereferenceable, AADereferenceableImpl,
DerefState> {
AADereferenceableReturned(const IRPosition &IRP)
: AAReturnedFromReturnedValues<AADereferenceable, AADereferenceableImpl,
DerefState>(IRP) {}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override {
STATS_DECLTRACK_FNRET_ATTR(dereferenceable)
}
};
/// Dereferenceable attribute for an argument
struct AADereferenceableArgument final
: AAArgumentFromCallSiteArgumentsAndMustBeExecutedContext<
AADereferenceable, AADereferenceableImpl, DerefState> {
using Base = AAArgumentFromCallSiteArgumentsAndMustBeExecutedContext<
AADereferenceable, AADereferenceableImpl, DerefState>;
AADereferenceableArgument(const IRPosition &IRP) : Base(IRP) {}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override {
STATS_DECLTRACK_ARG_ATTR(dereferenceable)
}
};
/// Dereferenceable attribute for a call site argument.
struct AADereferenceableCallSiteArgument final : AADereferenceableFloating {
AADereferenceableCallSiteArgument(const IRPosition &IRP)
: AADereferenceableFloating(IRP) {}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override {
STATS_DECLTRACK_CSARG_ATTR(dereferenceable)
}
};
/// Dereferenceable attribute deduction for a call site return value.
struct AADereferenceableCallSiteReturned final
: AACallSiteReturnedFromReturnedAndMustBeExecutedContext<
AADereferenceable, AADereferenceableImpl> {
using Base = AACallSiteReturnedFromReturnedAndMustBeExecutedContext<
AADereferenceable, AADereferenceableImpl>;
AADereferenceableCallSiteReturned(const IRPosition &IRP) : Base(IRP) {}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override {
STATS_DECLTRACK_CS_ATTR(dereferenceable);
}
};
// ------------------------ Align Argument Attribute ------------------------
static unsigned int getKnownAlignForUse(Attributor &A,
AbstractAttribute &QueryingAA,
Value &AssociatedValue, const Use *U,
const Instruction *I, bool &TrackUse) {
// We need to follow common pointer manipulation uses to the accesses they
// feed into.
if (isa<CastInst>(I)) {
// Follow all but ptr2int casts.
TrackUse = !isa<PtrToIntInst>(I);
return 0;
}
if (auto *GEP = dyn_cast<GetElementPtrInst>(I)) {
if (GEP->hasAllConstantIndices()) {
TrackUse = true;
return 0;
}
}
unsigned Alignment = 0;
if (ImmutableCallSite ICS = ImmutableCallSite(I)) {
if (ICS.isBundleOperand(U) || ICS.isCallee(U))
return 0;
unsigned ArgNo = ICS.getArgumentNo(U);
IRPosition IRP = IRPosition::callsite_argument(ICS, ArgNo);
// As long as we only use known information there is no need to track
// dependences here.
auto &AlignAA = A.getAAFor<AAAlign>(QueryingAA, IRP,
/* TrackDependence */ false);
Alignment = AlignAA.getKnownAlign();
}
const Value *UseV = U->get();
if (auto *SI = dyn_cast<StoreInst>(I))
Alignment = SI->getAlignment();
else if (auto *LI = dyn_cast<LoadInst>(I))
Alignment = LI->getAlignment();
if (Alignment <= 1)
return 0;
auto &DL = A.getDataLayout();
int64_t Offset;
if (const Value *Base = GetPointerBaseWithConstantOffset(UseV, Offset, DL)) {
if (Base == &AssociatedValue) {
// BasePointerAddr + Offset = Alignment * Q for some integer Q.
// So we can say that the maximum power of two which is a divisor of
// gcd(Offset, Alignment) is an alignment.
uint32_t gcd =
greatestCommonDivisor(uint32_t(abs((int32_t)Offset)), Alignment);
Alignment = llvm::PowerOf2Floor(gcd);
}
}
return Alignment;
}
struct AAAlignImpl : AAAlign {
AAAlignImpl(const IRPosition &IRP) : AAAlign(IRP) {}
/// See AbstractAttribute::initialize(...).
void initialize(Attributor &A) override {
SmallVector<Attribute, 4> Attrs;
getAttrs({Attribute::Alignment}, Attrs);
for (const Attribute &Attr : Attrs)
takeKnownMaximum(Attr.getValueAsInt());
if (getIRPosition().isFnInterfaceKind() &&
(!getAssociatedFunction() ||
!getAssociatedFunction()->hasExactDefinition()))
indicatePessimisticFixpoint();
}
/// See AbstractAttribute::manifest(...).
ChangeStatus manifest(Attributor &A) override {
ChangeStatus Changed = ChangeStatus::UNCHANGED;
// Check for users that allow alignment annotations.
Value &AnchorVal = getIRPosition().getAnchorValue();
for (const Use &U : AnchorVal.uses()) {
if (auto *SI = dyn_cast<StoreInst>(U.getUser())) {
if (SI->getPointerOperand() == &AnchorVal)
if (SI->getAlignment() < getAssumedAlign()) {
STATS_DECLTRACK(AAAlign, Store,
"Number of times alignemnt added to a store");
SI->setAlignment(Align(getAssumedAlign()));
Changed = ChangeStatus::CHANGED;
}
} else if (auto *LI = dyn_cast<LoadInst>(U.getUser())) {
if (LI->getPointerOperand() == &AnchorVal)
if (LI->getAlignment() < getAssumedAlign()) {
LI->setAlignment(Align(getAssumedAlign()));
STATS_DECLTRACK(AAAlign, Load,
"Number of times alignemnt added to a load");
Changed = ChangeStatus::CHANGED;
}
}
}
return AAAlign::manifest(A) | Changed;
}
// TODO: Provide a helper to determine the implied ABI alignment and check in
// the existing manifest method and a new one for AAAlignImpl that value
// to avoid making the alignment explicit if it did not improve.
/// See AbstractAttribute::getDeducedAttributes
virtual void
getDeducedAttributes(LLVMContext &Ctx,
SmallVectorImpl<Attribute> &Attrs) const override {
if (getAssumedAlign() > 1)
Attrs.emplace_back(
Attribute::getWithAlignment(Ctx, Align(getAssumedAlign())));
}
/// See AAFromMustBeExecutedContext
bool followUse(Attributor &A, const Use *U, const Instruction *I) {
bool TrackUse = false;
unsigned int KnownAlign =
getKnownAlignForUse(A, *this, getAssociatedValue(), U, I, TrackUse);
takeKnownMaximum(KnownAlign);
return TrackUse;
}
/// See AbstractAttribute::getAsStr().
const std::string getAsStr() const override {
return getAssumedAlign() ? ("align<" + std::to_string(getKnownAlign()) +
"-" + std::to_string(getAssumedAlign()) + ">")
: "unknown-align";
}
};
/// Align attribute for a floating value.
struct AAAlignFloating : AAFromMustBeExecutedContext<AAAlign, AAAlignImpl> {
using Base = AAFromMustBeExecutedContext<AAAlign, AAAlignImpl>;
AAAlignFloating(const IRPosition &IRP) : Base(IRP) {}
/// See AbstractAttribute::updateImpl(...).
ChangeStatus updateImpl(Attributor &A) override {
Base::updateImpl(A);
const DataLayout &DL = A.getDataLayout();
auto VisitValueCB = [&](Value &V, AAAlign::StateType &T,
bool Stripped) -> bool {
const auto &AA = A.getAAFor<AAAlign>(*this, IRPosition::value(V));
if (!Stripped && this == &AA) {
// Use only IR information if we did not strip anything.
const MaybeAlign PA = V.getPointerAlignment(DL);
T.takeKnownMaximum(PA ? PA->value() : 0);
T.indicatePessimisticFixpoint();
} else {
// Use abstract attribute information.
const AAAlign::StateType &DS =
static_cast<const AAAlign::StateType &>(AA.getState());
T ^= DS;
}
return T.isValidState();
};
StateType T;
if (!genericValueTraversal<AAAlign, StateType>(A, getIRPosition(), *this, T,
VisitValueCB))
return indicatePessimisticFixpoint();
// TODO: If we know we visited all incoming values, thus no are assumed
// dead, we can take the known information from the state T.
return clampStateAndIndicateChange(getState(), T);
}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override { STATS_DECLTRACK_FLOATING_ATTR(align) }
};
/// Align attribute for function return value.
struct AAAlignReturned final
: AAReturnedFromReturnedValues<AAAlign, AAAlignImpl> {
AAAlignReturned(const IRPosition &IRP)
: AAReturnedFromReturnedValues<AAAlign, AAAlignImpl>(IRP) {}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override { STATS_DECLTRACK_FNRET_ATTR(aligned) }
};
/// Align attribute for function argument.
struct AAAlignArgument final
: AAArgumentFromCallSiteArgumentsAndMustBeExecutedContext<AAAlign,
AAAlignImpl> {
AAAlignArgument(const IRPosition &IRP)
: AAArgumentFromCallSiteArgumentsAndMustBeExecutedContext<AAAlign,
AAAlignImpl>(
IRP) {}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override { STATS_DECLTRACK_ARG_ATTR(aligned) }
};
struct AAAlignCallSiteArgument final : AAAlignFloating {
AAAlignCallSiteArgument(const IRPosition &IRP) : AAAlignFloating(IRP) {}
/// See AbstractAttribute::manifest(...).
ChangeStatus manifest(Attributor &A) override {
return AAAlignImpl::manifest(A);
}
/// See AbstractAttribute::updateImpl(Attributor &A).
ChangeStatus updateImpl(Attributor &A) override {
ChangeStatus Changed = AAAlignFloating::updateImpl(A);
if (Argument *Arg = getAssociatedArgument()) {
const auto &ArgAlignAA = A.getAAFor<AAAlign>(
*this, IRPosition::argument(*Arg), /* TrackDependence */ false,
DepClassTy::OPTIONAL);
takeKnownMaximum(ArgAlignAA.getKnownAlign());
}
return Changed;
}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override { STATS_DECLTRACK_CSARG_ATTR(aligned) }
};
/// Align attribute deduction for a call site return value.
struct AAAlignCallSiteReturned final
: AACallSiteReturnedFromReturnedAndMustBeExecutedContext<AAAlign,
AAAlignImpl> {
using Base =
AACallSiteReturnedFromReturnedAndMustBeExecutedContext<AAAlign,
AAAlignImpl>;
AAAlignCallSiteReturned(const IRPosition &IRP) : Base(IRP) {}
/// See AbstractAttribute::initialize(...).
void initialize(Attributor &A) override {
Base::initialize(A);
Function *F = getAssociatedFunction();
if (!F)
indicatePessimisticFixpoint();
}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override { STATS_DECLTRACK_CS_ATTR(align); }
};
/// ------------------ Function No-Return Attribute ----------------------------
struct AANoReturnImpl : public AANoReturn {
AANoReturnImpl(const IRPosition &IRP) : AANoReturn(IRP) {}
/// See AbstractAttribute::initialize(...).
void initialize(Attributor &A) override {
AANoReturn::initialize(A);
Function *F = getAssociatedFunction();
if (!F)
indicatePessimisticFixpoint();
}
/// See AbstractAttribute::getAsStr().
const std::string getAsStr() const override {
return getAssumed() ? "noreturn" : "may-return";
}
/// See AbstractAttribute::updateImpl(Attributor &A).
virtual ChangeStatus updateImpl(Attributor &A) override {
auto CheckForNoReturn = [](Instruction &) { return false; };
if (!A.checkForAllInstructions(CheckForNoReturn, *this,
{(unsigned)Instruction::Ret}))
return indicatePessimisticFixpoint();
return ChangeStatus::UNCHANGED;
}
};
struct AANoReturnFunction final : AANoReturnImpl {
AANoReturnFunction(const IRPosition &IRP) : AANoReturnImpl(IRP) {}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override { STATS_DECLTRACK_FN_ATTR(noreturn) }
};
/// NoReturn attribute deduction for a call sites.
struct AANoReturnCallSite final : AANoReturnImpl {
AANoReturnCallSite(const IRPosition &IRP) : AANoReturnImpl(IRP) {}
/// See AbstractAttribute::updateImpl(...).
ChangeStatus updateImpl(Attributor &A) override {
// TODO: Once we have call site specific value information we can provide
// call site specific liveness information and then it makes
// sense to specialize attributes for call sites arguments instead of
// redirecting requests to the callee argument.
Function *F = getAssociatedFunction();
const IRPosition &FnPos = IRPosition::function(*F);
auto &FnAA = A.getAAFor<AANoReturn>(*this, FnPos);
return clampStateAndIndicateChange(
getState(),
static_cast<const AANoReturn::StateType &>(FnAA.getState()));
}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override { STATS_DECLTRACK_CS_ATTR(noreturn); }
};
/// ----------------------- Variable Capturing ---------------------------------
/// A class to hold the state of for no-capture attributes.
struct AANoCaptureImpl : public AANoCapture {
AANoCaptureImpl(const IRPosition &IRP) : AANoCapture(IRP) {}
/// See AbstractAttribute::initialize(...).
void initialize(Attributor &A) override {
if (hasAttr(getAttrKind(), /* IgnoreSubsumingPositions */ true)) {
indicateOptimisticFixpoint();
return;
}
Function *AnchorScope = getAnchorScope();
if (isFnInterfaceKind() &&
(!AnchorScope || !AnchorScope->hasExactDefinition())) {
indicatePessimisticFixpoint();
return;
}
// You cannot "capture" null in the default address space.
if (isa<ConstantPointerNull>(getAssociatedValue()) &&
getAssociatedValue().getType()->getPointerAddressSpace() == 0) {
indicateOptimisticFixpoint();
return;
}
const Function *F = getArgNo() >= 0 ? getAssociatedFunction() : AnchorScope;
// Check what state the associated function can actually capture.
if (F)
determineFunctionCaptureCapabilities(getIRPosition(), *F, *this);
else
indicatePessimisticFixpoint();
}
/// See AbstractAttribute::updateImpl(...).
ChangeStatus updateImpl(Attributor &A) override;
/// see AbstractAttribute::isAssumedNoCaptureMaybeReturned(...).
virtual void
getDeducedAttributes(LLVMContext &Ctx,
SmallVectorImpl<Attribute> &Attrs) const override {
if (!isAssumedNoCaptureMaybeReturned())
return;
if (getArgNo() >= 0) {
if (isAssumedNoCapture())
Attrs.emplace_back(Attribute::get(Ctx, Attribute::NoCapture));
else if (ManifestInternal)
Attrs.emplace_back(Attribute::get(Ctx, "no-capture-maybe-returned"));
}
}
/// Set the NOT_CAPTURED_IN_MEM and NOT_CAPTURED_IN_RET bits in \p Known
/// depending on the ability of the function associated with \p IRP to capture
/// state in memory and through "returning/throwing", respectively.
static void determineFunctionCaptureCapabilities(const IRPosition &IRP,
const Function &F,
BitIntegerState &State) {
// TODO: Once we have memory behavior attributes we should use them here.
// If we know we cannot communicate or write to memory, we do not care about
// ptr2int anymore.
if (F.onlyReadsMemory() && F.doesNotThrow() &&
F.getReturnType()->isVoidTy()) {
State.addKnownBits(NO_CAPTURE);
return;
}
// A function cannot capture state in memory if it only reads memory, it can
// however return/throw state and the state might be influenced by the
// pointer value, e.g., loading from a returned pointer might reveal a bit.
if (F.onlyReadsMemory())
State.addKnownBits(NOT_CAPTURED_IN_MEM);
// A function cannot communicate state back if it does not through
// exceptions and doesn not return values.
if (F.doesNotThrow() && F.getReturnType()->isVoidTy())
State.addKnownBits(NOT_CAPTURED_IN_RET);
// Check existing "returned" attributes.
int ArgNo = IRP.getArgNo();
if (F.doesNotThrow() && ArgNo >= 0) {
for (unsigned u = 0, e = F.arg_size(); u < e; ++u)
if (F.hasParamAttribute(u, Attribute::Returned)) {
if (u == unsigned(ArgNo))
State.removeAssumedBits(NOT_CAPTURED_IN_RET);
else if (F.onlyReadsMemory())
State.addKnownBits(NO_CAPTURE);
else
State.addKnownBits(NOT_CAPTURED_IN_RET);
break;
}
}
}
/// See AbstractState::getAsStr().
const std::string getAsStr() const override {
if (isKnownNoCapture())
return "known not-captured";
if (isAssumedNoCapture())
return "assumed not-captured";
if (isKnownNoCaptureMaybeReturned())
return "known not-captured-maybe-returned";
if (isAssumedNoCaptureMaybeReturned())
return "assumed not-captured-maybe-returned";
return "assumed-captured";
}
};
/// Attributor-aware capture tracker.
struct AACaptureUseTracker final : public CaptureTracker {
/// Create a capture tracker that can lookup in-flight abstract attributes
/// through the Attributor \p A.
///
/// If a use leads to a potential capture, \p CapturedInMemory is set and the
/// search is stopped. If a use leads to a return instruction,
/// \p CommunicatedBack is set to true and \p CapturedInMemory is not changed.
/// If a use leads to a ptr2int which may capture the value,
/// \p CapturedInInteger is set. If a use is found that is currently assumed
/// "no-capture-maybe-returned", the user is added to the \p PotentialCopies
/// set. All values in \p PotentialCopies are later tracked as well. For every
/// explored use we decrement \p RemainingUsesToExplore. Once it reaches 0,
/// the search is stopped with \p CapturedInMemory and \p CapturedInInteger
/// conservatively set to true.
AACaptureUseTracker(Attributor &A, AANoCapture &NoCaptureAA,
const AAIsDead &IsDeadAA, AANoCapture::StateType &State,
SmallVectorImpl<const Value *> &PotentialCopies,
unsigned &RemainingUsesToExplore)
: A(A), NoCaptureAA(NoCaptureAA), IsDeadAA(IsDeadAA), State(State),
PotentialCopies(PotentialCopies),
RemainingUsesToExplore(RemainingUsesToExplore) {}
/// Determine if \p V maybe captured. *Also updates the state!*
bool valueMayBeCaptured(const Value *V) {
if (V->getType()->isPointerTy()) {
PointerMayBeCaptured(V, this);
} else {
State.indicatePessimisticFixpoint();
}
return State.isAssumed(AANoCapture::NO_CAPTURE_MAYBE_RETURNED);
}
/// See CaptureTracker::tooManyUses().
void tooManyUses() override {
State.removeAssumedBits(AANoCapture::NO_CAPTURE);
}
bool isDereferenceableOrNull(Value *O, const DataLayout &DL) override {
if (CaptureTracker::isDereferenceableOrNull(O, DL))
return true;
const auto &DerefAA =
A.getAAFor<AADereferenceable>(NoCaptureAA, IRPosition::value(*O));
return DerefAA.getAssumedDereferenceableBytes();
}
/// See CaptureTracker::captured(...).
bool captured(const Use *U) override {
Instruction *UInst = cast<Instruction>(U->getUser());
LLVM_DEBUG(dbgs() << "Check use: " << *U->get() << " in " << *UInst
<< "\n");
// Because we may reuse the tracker multiple times we keep track of the
// number of explored uses ourselves as well.
if (RemainingUsesToExplore-- == 0) {
LLVM_DEBUG(dbgs() << " - too many uses to explore!\n");
return isCapturedIn(/* Memory */ true, /* Integer */ true,
/* Return */ true);
}
// Deal with ptr2int by following uses.
if (isa<PtrToIntInst>(UInst)) {
LLVM_DEBUG(dbgs() << " - ptr2int assume the worst!\n");
return valueMayBeCaptured(UInst);
}
// Explicitly catch return instructions.
if (isa<ReturnInst>(UInst))
return isCapturedIn(/* Memory */ false, /* Integer */ false,
/* Return */ true);
// For now we only use special logic for call sites. However, the tracker
// itself knows about a lot of other non-capturing cases already.
CallSite CS(UInst);
if (!CS || !CS.isArgOperand(U))
return isCapturedIn(/* Memory */ true, /* Integer */ true,
/* Return */ true);
unsigned ArgNo = CS.getArgumentNo(U);
const IRPosition &CSArgPos = IRPosition::callsite_argument(CS, ArgNo);
// If we have a abstract no-capture attribute for the argument we can use
// it to justify a non-capture attribute here. This allows recursion!
auto &ArgNoCaptureAA = A.getAAFor<AANoCapture>(NoCaptureAA, CSArgPos);
if (ArgNoCaptureAA.isAssumedNoCapture())
return isCapturedIn(/* Memory */ false, /* Integer */ false,
/* Return */ false);
if (ArgNoCaptureAA.isAssumedNoCaptureMaybeReturned()) {
addPotentialCopy(CS);
return isCapturedIn(/* Memory */ false, /* Integer */ false,
/* Return */ false);
}
// Lastly, we could not find a reason no-capture can be assumed so we don't.
return isCapturedIn(/* Memory */ true, /* Integer */ true,
/* Return */ true);
}
/// Register \p CS as potential copy of the value we are checking.
void addPotentialCopy(CallSite CS) {
PotentialCopies.push_back(CS.getInstruction());
}
/// See CaptureTracker::shouldExplore(...).
bool shouldExplore(const Use *U) override {
// Check liveness.
return !IsDeadAA.isAssumedDead(cast<Instruction>(U->getUser()));
}
/// Update the state according to \p CapturedInMem, \p CapturedInInt, and
/// \p CapturedInRet, then return the appropriate value for use in the
/// CaptureTracker::captured() interface.
bool isCapturedIn(bool CapturedInMem, bool CapturedInInt,
bool CapturedInRet) {
LLVM_DEBUG(dbgs() << " - captures [Mem " << CapturedInMem << "|Int "
<< CapturedInInt << "|Ret " << CapturedInRet << "]\n");
if (CapturedInMem)
State.removeAssumedBits(AANoCapture::NOT_CAPTURED_IN_MEM);
if (CapturedInInt)
State.removeAssumedBits(AANoCapture::NOT_CAPTURED_IN_INT);
if (CapturedInRet)
State.removeAssumedBits(AANoCapture::NOT_CAPTURED_IN_RET);
return !State.isAssumed(AANoCapture::NO_CAPTURE_MAYBE_RETURNED);
}
private:
/// The attributor providing in-flight abstract attributes.
Attributor &A;
/// The abstract attribute currently updated.
AANoCapture &NoCaptureAA;
/// The abstract liveness state.
const AAIsDead &IsDeadAA;
/// The state currently updated.
AANoCapture::StateType &State;
/// Set of potential copies of the tracked value.
SmallVectorImpl<const Value *> &PotentialCopies;
/// Global counter to limit the number of explored uses.
unsigned &RemainingUsesToExplore;
};
ChangeStatus AANoCaptureImpl::updateImpl(Attributor &A) {
const IRPosition &IRP = getIRPosition();
const Value *V =
getArgNo() >= 0 ? IRP.getAssociatedArgument() : &IRP.getAssociatedValue();
if (!V)
return indicatePessimisticFixpoint();
const Function *F =
getArgNo() >= 0 ? IRP.getAssociatedFunction() : IRP.getAnchorScope();
assert(F && "Expected a function!");
const IRPosition &FnPos = IRPosition::function(*F);
const auto &IsDeadAA = A.getAAFor<AAIsDead>(*this, FnPos);
AANoCapture::StateType T;
// Readonly means we cannot capture through memory.
const auto &FnMemAA = A.getAAFor<AAMemoryBehavior>(*this, FnPos);
if (FnMemAA.isAssumedReadOnly()) {
T.addKnownBits(NOT_CAPTURED_IN_MEM);
if (FnMemAA.isKnownReadOnly())
addKnownBits(NOT_CAPTURED_IN_MEM);
}
// Make sure all returned values are different than the underlying value.
// TODO: we could do this in a more sophisticated way inside
// AAReturnedValues, e.g., track all values that escape through returns
// directly somehow.
auto CheckReturnedArgs = [&](const AAReturnedValues &RVAA) {
bool SeenConstant = false;
for (auto &It : RVAA.returned_values()) {
if (isa<Constant>(It.first)) {
if (SeenConstant)
return false;
SeenConstant = true;
} else if (!isa<Argument>(It.first) ||
It.first == getAssociatedArgument())
return false;
}
return true;
};
const auto &NoUnwindAA = A.getAAFor<AANoUnwind>(*this, FnPos);
if (NoUnwindAA.isAssumedNoUnwind()) {
bool IsVoidTy = F->getReturnType()->isVoidTy();
const AAReturnedValues *RVAA =
IsVoidTy ? nullptr : &A.getAAFor<AAReturnedValues>(*this, FnPos);
if (IsVoidTy || CheckReturnedArgs(*RVAA)) {
T.addKnownBits(NOT_CAPTURED_IN_RET);
if (T.isKnown(NOT_CAPTURED_IN_MEM))
return ChangeStatus::UNCHANGED;
if (NoUnwindAA.isKnownNoUnwind() &&
(IsVoidTy || RVAA->getState().isAtFixpoint())) {
addKnownBits(NOT_CAPTURED_IN_RET);
if (isKnown(NOT_CAPTURED_IN_MEM))
return indicateOptimisticFixpoint();
}
}
}
// Use the CaptureTracker interface and logic with the specialized tracker,
// defined in AACaptureUseTracker, that can look at in-flight abstract
// attributes and directly updates the assumed state.
SmallVector<const Value *, 4> PotentialCopies;
unsigned RemainingUsesToExplore = DefaultMaxUsesToExplore;
AACaptureUseTracker Tracker(A, *this, IsDeadAA, T, PotentialCopies,
RemainingUsesToExplore);
// Check all potential copies of the associated value until we can assume
// none will be captured or we have to assume at least one might be.
unsigned Idx = 0;
PotentialCopies.push_back(V);
while (T.isAssumed(NO_CAPTURE_MAYBE_RETURNED) && Idx < PotentialCopies.size())
Tracker.valueMayBeCaptured(PotentialCopies[Idx++]);
AANoCapture::StateType &S = getState();
auto Assumed = S.getAssumed();
S.intersectAssumedBits(T.getAssumed());
if (!isAssumedNoCaptureMaybeReturned())
return indicatePessimisticFixpoint();
return Assumed == S.getAssumed() ? ChangeStatus::UNCHANGED
: ChangeStatus::CHANGED;
}
/// NoCapture attribute for function arguments.
struct AANoCaptureArgument final : AANoCaptureImpl {
AANoCaptureArgument(const IRPosition &IRP) : AANoCaptureImpl(IRP) {}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override { STATS_DECLTRACK_ARG_ATTR(nocapture) }
};
/// NoCapture attribute for call site arguments.
struct AANoCaptureCallSiteArgument final : AANoCaptureImpl {
AANoCaptureCallSiteArgument(const IRPosition &IRP) : AANoCaptureImpl(IRP) {}
/// See AbstractAttribute::initialize(...).
void initialize(Attributor &A) override {
if (Argument *Arg = getAssociatedArgument())
if (Arg->hasByValAttr())
indicateOptimisticFixpoint();
AANoCaptureImpl::initialize(A);
}
/// See AbstractAttribute::updateImpl(...).
ChangeStatus updateImpl(Attributor &A) override {
// TODO: Once we have call site specific value information we can provide
// call site specific liveness information and then it makes
// sense to specialize attributes for call sites arguments instead of
// redirecting requests to the callee argument.
Argument *Arg = getAssociatedArgument();
if (!Arg)
return indicatePessimisticFixpoint();
const IRPosition &ArgPos = IRPosition::argument(*Arg);
auto &ArgAA = A.getAAFor<AANoCapture>(*this, ArgPos);
return clampStateAndIndicateChange(
getState(),
static_cast<const AANoCapture::StateType &>(ArgAA.getState()));
}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override{STATS_DECLTRACK_CSARG_ATTR(nocapture)};
};
/// NoCapture attribute for floating values.
struct AANoCaptureFloating final : AANoCaptureImpl {
AANoCaptureFloating(const IRPosition &IRP) : AANoCaptureImpl(IRP) {}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override {
STATS_DECLTRACK_FLOATING_ATTR(nocapture)
}
};
/// NoCapture attribute for function return value.
struct AANoCaptureReturned final : AANoCaptureImpl {
AANoCaptureReturned(const IRPosition &IRP) : AANoCaptureImpl(IRP) {
llvm_unreachable("NoCapture is not applicable to function returns!");
}
/// See AbstractAttribute::initialize(...).
void initialize(Attributor &A) override {
llvm_unreachable("NoCapture is not applicable to function returns!");
}
/// See AbstractAttribute::updateImpl(...).
ChangeStatus updateImpl(Attributor &A) override {
llvm_unreachable("NoCapture is not applicable to function returns!");
}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override {}
};
/// NoCapture attribute deduction for a call site return value.
struct AANoCaptureCallSiteReturned final : AANoCaptureImpl {
AANoCaptureCallSiteReturned(const IRPosition &IRP) : AANoCaptureImpl(IRP) {}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override {
STATS_DECLTRACK_CSRET_ATTR(nocapture)
}
};
/// ------------------ Value Simplify Attribute ----------------------------
struct AAValueSimplifyImpl : AAValueSimplify {
AAValueSimplifyImpl(const IRPosition &IRP) : AAValueSimplify(IRP) {}
/// See AbstractAttribute::getAsStr().
const std::string getAsStr() const override {
return getAssumed() ? (getKnown() ? "simplified" : "maybe-simple")
: "not-simple";
}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override {}
/// See AAValueSimplify::getAssumedSimplifiedValue()
Optional<Value *> getAssumedSimplifiedValue(Attributor &A) const override {
if (!getAssumed())
return const_cast<Value *>(&getAssociatedValue());
return SimplifiedAssociatedValue;
}
void initialize(Attributor &A) override {}
/// Helper function for querying AAValueSimplify and updating candicate.
/// \param QueryingValue Value trying to unify with SimplifiedValue
/// \param AccumulatedSimplifiedValue Current simplification result.
static bool checkAndUpdate(Attributor &A, const AbstractAttribute &QueryingAA,
Value &QueryingValue,
Optional<Value *> &AccumulatedSimplifiedValue) {
// FIXME: Add a typecast support.
auto &ValueSimpifyAA = A.getAAFor<AAValueSimplify>(
QueryingAA, IRPosition::value(QueryingValue));
Optional<Value *> QueryingValueSimplified =
ValueSimpifyAA.getAssumedSimplifiedValue(A);
if (!QueryingValueSimplified.hasValue())
return true;
if (!QueryingValueSimplified.getValue())
return false;
Value &QueryingValueSimplifiedUnwrapped =
*QueryingValueSimplified.getValue();
if (isa<UndefValue>(QueryingValueSimplifiedUnwrapped))
return true;
if (AccumulatedSimplifiedValue.hasValue())
return AccumulatedSimplifiedValue == QueryingValueSimplified;
LLVM_DEBUG(dbgs() << "[Attributor][ValueSimplify] " << QueryingValue
<< " is assumed to be "
<< QueryingValueSimplifiedUnwrapped << "\n");
AccumulatedSimplifiedValue = QueryingValueSimplified;
return true;
}
/// See AbstractAttribute::manifest(...).
ChangeStatus manifest(Attributor &A) override {
ChangeStatus Changed = ChangeStatus::UNCHANGED;
if (!SimplifiedAssociatedValue.hasValue() ||
!SimplifiedAssociatedValue.getValue())
return Changed;
if (auto *C = dyn_cast<Constant>(SimplifiedAssociatedValue.getValue())) {
// We can replace the AssociatedValue with the constant.
Value &V = getAssociatedValue();
if (!V.user_empty() && &V != C && V.getType() == C->getType()) {
LLVM_DEBUG(dbgs() << "[Attributor][ValueSimplify] " << V << " -> " << *C
<< "\n");
A.changeValueAfterManifest(V, *C);
Changed = ChangeStatus::CHANGED;
}
}
return Changed | AAValueSimplify::manifest(A);
}
/// See AbstractState::indicatePessimisticFixpoint(...).
ChangeStatus indicatePessimisticFixpoint() override {
// NOTE: Associated value will be returned in a pessimistic fixpoint and is
// regarded as known. That's why`indicateOptimisticFixpoint` is called.
SimplifiedAssociatedValue = &getAssociatedValue();
indicateOptimisticFixpoint();
return ChangeStatus::CHANGED;
}
protected:
// An assumed simplified value. Initially, it is set to Optional::None, which
// means that the value is not clear under current assumption. If in the
// pessimistic state, getAssumedSimplifiedValue doesn't return this value but
// returns orignal associated value.
Optional<Value *> SimplifiedAssociatedValue;
};
struct AAValueSimplifyArgument final : AAValueSimplifyImpl {
AAValueSimplifyArgument(const IRPosition &IRP) : AAValueSimplifyImpl(IRP) {}
void initialize(Attributor &A) override {
AAValueSimplifyImpl::initialize(A);
if (!getAssociatedFunction() || getAssociatedFunction()->isDeclaration())
indicatePessimisticFixpoint();
if (hasAttr({Attribute::InAlloca, Attribute::StructRet, Attribute::Nest},
/* IgnoreSubsumingPositions */ true))
indicatePessimisticFixpoint();
}
/// See AbstractAttribute::updateImpl(...).
ChangeStatus updateImpl(Attributor &A) override {
// Byval is only replacable if it is readonly otherwise we would write into
// the replaced value and not the copy that byval creates implicitly.
Argument *Arg = getAssociatedArgument();
if (Arg->hasByValAttr()) {
const auto &MemAA = A.getAAFor<AAMemoryBehavior>(*this, getIRPosition());
if (!MemAA.isAssumedReadOnly())
return indicatePessimisticFixpoint();
}
bool HasValueBefore = SimplifiedAssociatedValue.hasValue();
auto PredForCallSite = [&](AbstractCallSite ACS) {
// Check if we have an associated argument or not (which can happen for
// callback calls).
Value *ArgOp = ACS.getCallArgOperand(getArgNo());
if (!ArgOp)
return false;
// We can only propagate thread independent values through callbacks.
// This is different to direct/indirect call sites because for them we
// know the thread executing the caller and callee is the same. For
// callbacks this is not guaranteed, thus a thread dependent value could
// be different for the caller and callee, making it invalid to propagate.
if (ACS.isCallbackCall())
if (auto *C = dyn_cast<Constant>(ArgOp))
if (C->isThreadDependent())
return false;
return checkAndUpdate(A, *this, *ArgOp, SimplifiedAssociatedValue);
};
if (!A.checkForAllCallSites(PredForCallSite, *this, true))
return indicatePessimisticFixpoint();
// If a candicate was found in this update, return CHANGED.
return HasValueBefore == SimplifiedAssociatedValue.hasValue()
? ChangeStatus::UNCHANGED
: ChangeStatus ::CHANGED;
}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override {
STATS_DECLTRACK_ARG_ATTR(value_simplify)
}
};
struct AAValueSimplifyReturned : AAValueSimplifyImpl {
AAValueSimplifyReturned(const IRPosition &IRP) : AAValueSimplifyImpl(IRP) {}
/// See AbstractAttribute::updateImpl(...).
ChangeStatus updateImpl(Attributor &A) override {
bool HasValueBefore = SimplifiedAssociatedValue.hasValue();
auto PredForReturned = [&](Value &V) {
return checkAndUpdate(A, *this, V, SimplifiedAssociatedValue);
};
if (!A.checkForAllReturnedValues(PredForReturned, *this))
return indicatePessimisticFixpoint();
// If a candicate was found in this update, return CHANGED.
return HasValueBefore == SimplifiedAssociatedValue.hasValue()
? ChangeStatus::UNCHANGED
: ChangeStatus ::CHANGED;
}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override {
STATS_DECLTRACK_FNRET_ATTR(value_simplify)
}
};
struct AAValueSimplifyFloating : AAValueSimplifyImpl {
AAValueSimplifyFloating(const IRPosition &IRP) : AAValueSimplifyImpl(IRP) {}
/// See AbstractAttribute::initialize(...).
void initialize(Attributor &A) override {
Value &V = getAnchorValue();
// TODO: add other stuffs
if (isa<Constant>(V))
indicatePessimisticFixpoint();
}
/// See AbstractAttribute::updateImpl(...).
ChangeStatus updateImpl(Attributor &A) override {
bool HasValueBefore = SimplifiedAssociatedValue.hasValue();
auto VisitValueCB = [&](Value &V, BooleanState, bool Stripped) -> bool {
auto &AA = A.getAAFor<AAValueSimplify>(*this, IRPosition::value(V));
if (!Stripped && this == &AA) {
// TODO: Look the instruction and check recursively.
LLVM_DEBUG(
dbgs() << "[Attributor][ValueSimplify] Can't be stripped more : "
<< V << "\n");
indicatePessimisticFixpoint();
return false;
}
return checkAndUpdate(A, *this, V, SimplifiedAssociatedValue);
};
if (!genericValueTraversal<AAValueSimplify, BooleanState>(
A, getIRPosition(), *this, static_cast<BooleanState &>(*this),
VisitValueCB))
return indicatePessimisticFixpoint();
// If a candicate was found in this update, return CHANGED.
return HasValueBefore == SimplifiedAssociatedValue.hasValue()
? ChangeStatus::UNCHANGED
: ChangeStatus ::CHANGED;
}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override {
STATS_DECLTRACK_FLOATING_ATTR(value_simplify)
}
};
struct AAValueSimplifyFunction : AAValueSimplifyImpl {
AAValueSimplifyFunction(const IRPosition &IRP) : AAValueSimplifyImpl(IRP) {}
/// See AbstractAttribute::initialize(...).
void initialize(Attributor &A) override {
SimplifiedAssociatedValue = &getAnchorValue();
indicateOptimisticFixpoint();
}
/// See AbstractAttribute::initialize(...).
ChangeStatus updateImpl(Attributor &A) override {
llvm_unreachable(
"AAValueSimplify(Function|CallSite)::updateImpl will not be called");
}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override {
STATS_DECLTRACK_FN_ATTR(value_simplify)
}
};
struct AAValueSimplifyCallSite : AAValueSimplifyFunction {
AAValueSimplifyCallSite(const IRPosition &IRP)
: AAValueSimplifyFunction(IRP) {}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override {
STATS_DECLTRACK_CS_ATTR(value_simplify)
}
};
struct AAValueSimplifyCallSiteReturned : AAValueSimplifyReturned {
AAValueSimplifyCallSiteReturned(const IRPosition &IRP)
: AAValueSimplifyReturned(IRP) {}
void trackStatistics() const override {
STATS_DECLTRACK_CSRET_ATTR(value_simplify)
}
};
struct AAValueSimplifyCallSiteArgument : AAValueSimplifyFloating {
AAValueSimplifyCallSiteArgument(const IRPosition &IRP)
: AAValueSimplifyFloating(IRP) {}
void trackStatistics() const override {
STATS_DECLTRACK_CSARG_ATTR(value_simplify)
}
};
/// ----------------------- Heap-To-Stack Conversion ---------------------------
struct AAHeapToStackImpl : public AAHeapToStack {
AAHeapToStackImpl(const IRPosition &IRP) : AAHeapToStack(IRP) {}
const std::string getAsStr() const override {
return "[H2S] Mallocs: " + std::to_string(MallocCalls.size());
}
ChangeStatus manifest(Attributor &A) override {
assert(getState().isValidState() &&
"Attempted to manifest an invalid state!");
ChangeStatus HasChanged = ChangeStatus::UNCHANGED;
Function *F = getAssociatedFunction();
const auto *TLI = A.getInfoCache().getTargetLibraryInfoForFunction(*F);
for (Instruction *MallocCall : MallocCalls) {
// This malloc cannot be replaced.
if (BadMallocCalls.count(MallocCall))
continue;
for (Instruction *FreeCall : FreesForMalloc[MallocCall]) {
LLVM_DEBUG(dbgs() << "H2S: Removing free call: " << *FreeCall << "\n");
A.deleteAfterManifest(*FreeCall);
HasChanged = ChangeStatus::CHANGED;
}
LLVM_DEBUG(dbgs() << "H2S: Removing malloc call: " << *MallocCall
<< "\n");
Constant *Size;
if (isCallocLikeFn(MallocCall, TLI)) {
auto *Num = cast<ConstantInt>(MallocCall->getOperand(0));
auto *SizeT = dyn_cast<ConstantInt>(MallocCall->getOperand(1));
APInt TotalSize = SizeT->getValue() * Num->getValue();
Size =
ConstantInt::get(MallocCall->getOperand(0)->getType(), TotalSize);
} else {
Size = cast<ConstantInt>(MallocCall->getOperand(0));
}
unsigned AS = cast<PointerType>(MallocCall->getType())->getAddressSpace();
Instruction *AI = new AllocaInst(Type::getInt8Ty(F->getContext()), AS,
Size, "", MallocCall->getNextNode());
if (AI->getType() != MallocCall->getType())
AI = new BitCastInst(AI, MallocCall->getType(), "malloc_bc",
AI->getNextNode());
replaceAllInstructionUsesWith(*MallocCall, *AI);
if (auto *II = dyn_cast<InvokeInst>(MallocCall)) {
auto *NBB = II->getNormalDest();
BranchInst::Create(NBB, MallocCall->getParent());
A.deleteAfterManifest(*MallocCall);
} else {
A.deleteAfterManifest(*MallocCall);
}
if (isCallocLikeFn(MallocCall, TLI)) {
auto *BI = new BitCastInst(AI, MallocCall->getType(), "calloc_bc",
AI->getNextNode());
Value *Ops[] = {
BI, ConstantInt::get(F->getContext(), APInt(8, 0, false)), Size,
ConstantInt::get(Type::getInt1Ty(F->getContext()), false)};
Type *Tys[] = {BI->getType(), MallocCall->getOperand(0)->getType()};
Module *M = F->getParent();
Function *Fn = Intrinsic::getDeclaration(M, Intrinsic::memset, Tys);
CallInst::Create(Fn, Ops, "", BI->getNextNode());
}
HasChanged = ChangeStatus::CHANGED;
}
return HasChanged;
}
/// Collection of all malloc calls in a function.
SmallSetVector<Instruction *, 4> MallocCalls;
/// Collection of malloc calls that cannot be converted.
DenseSet<const Instruction *> BadMallocCalls;
/// A map for each malloc call to the set of associated free calls.
DenseMap<Instruction *, SmallPtrSet<Instruction *, 4>> FreesForMalloc;
ChangeStatus updateImpl(Attributor &A) override;
};
ChangeStatus AAHeapToStackImpl::updateImpl(Attributor &A) {
const Function *F = getAssociatedFunction();
const auto *TLI = A.getInfoCache().getTargetLibraryInfoForFunction(*F);
MustBeExecutedContextExplorer &Explorer =
A.getInfoCache().getMustBeExecutedContextExplorer();
auto FreeCheck = [&](Instruction &I) {
const auto &Frees = FreesForMalloc.lookup(&I);
if (Frees.size() != 1)
return false;
Instruction *UniqueFree = *Frees.begin();
return Explorer.findInContextOf(UniqueFree, I.getNextNode());
};
auto UsesCheck = [&](Instruction &I) {
bool ValidUsesOnly = true;
bool MustUse = true;
auto Pred = [&](const Use &U, bool &Follow) -> bool {
Instruction *UserI = cast<Instruction>(U.getUser());
if (isa<LoadInst>(UserI))
return true;
if (auto *SI = dyn_cast<StoreInst>(UserI)) {
if (SI->getValueOperand() == U.get()) {
LLVM_DEBUG(dbgs()
<< "[H2S] escaping store to memory: " << *UserI << "\n");
ValidUsesOnly = false;
} else {
// A store into the malloc'ed memory is fine.
}
return true;
}
if (auto *CB = dyn_cast<CallBase>(UserI)) {
if (!CB->isArgOperand(&U) || CB->isLifetimeStartOrEnd())
return true;
// Record malloc.
if (isFreeCall(UserI, TLI)) {
if (MustUse) {
FreesForMalloc[&I].insert(UserI);
} else {
LLVM_DEBUG(dbgs() << "[H2S] free potentially on different mallocs: "
<< *UserI << "\n");
ValidUsesOnly = false;
}
return true;
}
unsigned ArgNo = CB->getArgOperandNo(&U);
const auto &NoCaptureAA = A.getAAFor<AANoCapture>(
*this, IRPosition::callsite_argument(*CB, ArgNo));
// If a callsite argument use is nofree, we are fine.
const auto &ArgNoFreeAA = A.getAAFor<AANoFree>(
*this, IRPosition::callsite_argument(*CB, ArgNo));
if (!NoCaptureAA.isAssumedNoCapture() ||
!ArgNoFreeAA.isAssumedNoFree()) {
LLVM_DEBUG(dbgs() << "[H2S] Bad user: " << *UserI << "\n");
ValidUsesOnly = false;
}
return true;
}
if (isa<GetElementPtrInst>(UserI) || isa<BitCastInst>(UserI) ||
isa<PHINode>(UserI) || isa<SelectInst>(UserI)) {
MustUse &= !(isa<PHINode>(UserI) || isa<SelectInst>(UserI));
Follow = true;
return true;
}
// Unknown user for which we can not track uses further (in a way that
// makes sense).
LLVM_DEBUG(dbgs() << "[H2S] Unknown user: " << *UserI << "\n");
ValidUsesOnly = false;
return true;
};
A.checkForAllUses(Pred, *this, I);
return ValidUsesOnly;
};
auto MallocCallocCheck = [&](Instruction &I) {
if (BadMallocCalls.count(&I))
return true;
bool IsMalloc = isMallocLikeFn(&I, TLI);
bool IsCalloc = !IsMalloc && isCallocLikeFn(&I, TLI);
if (!IsMalloc && !IsCalloc) {
BadMallocCalls.insert(&I);
return true;
}
if (IsMalloc) {
if (auto *Size = dyn_cast<ConstantInt>(I.getOperand(0)))
if (Size->getValue().ule(MaxHeapToStackSize))
if (UsesCheck(I) || FreeCheck(I)) {
MallocCalls.insert(&I);
return true;
}
} else if (IsCalloc) {
bool Overflow = false;
if (auto *Num = dyn_cast<ConstantInt>(I.getOperand(0)))
if (auto *Size = dyn_cast<ConstantInt>(I.getOperand(1)))
if ((Size->getValue().umul_ov(Num->getValue(), Overflow))
.ule(MaxHeapToStackSize))
if (!Overflow && (UsesCheck(I) || FreeCheck(I))) {
MallocCalls.insert(&I);
return true;
}
}
BadMallocCalls.insert(&I);
return true;
};
size_t NumBadMallocs = BadMallocCalls.size();
A.checkForAllCallLikeInstructions(MallocCallocCheck, *this);
if (NumBadMallocs != BadMallocCalls.size())
return ChangeStatus::CHANGED;
return ChangeStatus::UNCHANGED;
}
struct AAHeapToStackFunction final : public AAHeapToStackImpl {
AAHeapToStackFunction(const IRPosition &IRP) : AAHeapToStackImpl(IRP) {}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override {
STATS_DECL(MallocCalls, Function,
"Number of malloc calls converted to allocas");
for (auto *C : MallocCalls)
if (!BadMallocCalls.count(C))
++BUILD_STAT_NAME(MallocCalls, Function);
}
};
/// -------------------- Memory Behavior Attributes ----------------------------
/// Includes read-none, read-only, and write-only.
/// ----------------------------------------------------------------------------
struct AAMemoryBehaviorImpl : public AAMemoryBehavior {
AAMemoryBehaviorImpl(const IRPosition &IRP) : AAMemoryBehavior(IRP) {}
/// See AbstractAttribute::initialize(...).
void initialize(Attributor &A) override {
intersectAssumedBits(BEST_STATE);
getKnownStateFromValue(getIRPosition(), getState());
IRAttribute::initialize(A);
}
/// Return the memory behavior information encoded in the IR for \p IRP.
static void getKnownStateFromValue(const IRPosition &IRP,
BitIntegerState &State,
bool IgnoreSubsumingPositions = false) {
SmallVector<Attribute, 2> Attrs;
IRP.getAttrs(AttrKinds, Attrs, IgnoreSubsumingPositions);
for (const Attribute &Attr : Attrs) {
switch (Attr.getKindAsEnum()) {
case Attribute::ReadNone:
State.addKnownBits(NO_ACCESSES);
break;
case Attribute::ReadOnly:
State.addKnownBits(NO_WRITES);
break;
case Attribute::WriteOnly:
State.addKnownBits(NO_READS);
break;
default:
llvm_unreachable("Unexpcted attribute!");
}
}
if (auto *I = dyn_cast<Instruction>(&IRP.getAnchorValue())) {
if (!I->mayReadFromMemory())
State.addKnownBits(NO_READS);
if (!I->mayWriteToMemory())
State.addKnownBits(NO_WRITES);
}
}
/// See AbstractAttribute::getDeducedAttributes(...).
void getDeducedAttributes(LLVMContext &Ctx,
SmallVectorImpl<Attribute> &Attrs) const override {
assert(Attrs.size() == 0);
if (isAssumedReadNone())
Attrs.push_back(Attribute::get(Ctx, Attribute::ReadNone));
else if (isAssumedReadOnly())
Attrs.push_back(Attribute::get(Ctx, Attribute::ReadOnly));
else if (isAssumedWriteOnly())
Attrs.push_back(Attribute::get(Ctx, Attribute::WriteOnly));
assert(Attrs.size() <= 1);
}
/// See AbstractAttribute::manifest(...).
ChangeStatus manifest(Attributor &A) override {
const IRPosition &IRP = getIRPosition();
// Check if we would improve the existing attributes first.
SmallVector<Attribute, 4> DeducedAttrs;
getDeducedAttributes(IRP.getAnchorValue().getContext(), DeducedAttrs);
if (llvm::all_of(DeducedAttrs, [&](const Attribute &Attr) {
return IRP.hasAttr(Attr.getKindAsEnum(),
/* IgnoreSubsumingPositions */ true);
}))
return ChangeStatus::UNCHANGED;
// Clear existing attributes.
IRP.removeAttrs(AttrKinds);
// Use the generic manifest method.
return IRAttribute::manifest(A);
}
/// See AbstractState::getAsStr().
const std::string getAsStr() const override {
if (isAssumedReadNone())
return "readnone";
if (isAssumedReadOnly())
return "readonly";
if (isAssumedWriteOnly())
return "writeonly";
return "may-read/write";
}
/// The set of IR attributes AAMemoryBehavior deals with.
static const Attribute::AttrKind AttrKinds[3];
};
const Attribute::AttrKind AAMemoryBehaviorImpl::AttrKinds[] = {
Attribute::ReadNone, Attribute::ReadOnly, Attribute::WriteOnly};
/// Memory behavior attribute for a floating value.
struct AAMemoryBehaviorFloating : AAMemoryBehaviorImpl {
AAMemoryBehaviorFloating(const IRPosition &IRP) : AAMemoryBehaviorImpl(IRP) {}
/// See AbstractAttribute::initialize(...).
void initialize(Attributor &A) override {
AAMemoryBehaviorImpl::initialize(A);
// Initialize the use vector with all direct uses of the associated value.
for (const Use &U : getAssociatedValue().uses())
Uses.insert(&U);
}
/// See AbstractAttribute::updateImpl(...).
ChangeStatus updateImpl(Attributor &A) override;
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override {
if (isAssumedReadNone())
STATS_DECLTRACK_FLOATING_ATTR(readnone)
else if (isAssumedReadOnly())
STATS_DECLTRACK_FLOATING_ATTR(readonly)
else if (isAssumedWriteOnly())
STATS_DECLTRACK_FLOATING_ATTR(writeonly)
}
private:
/// Return true if users of \p UserI might access the underlying
/// variable/location described by \p U and should therefore be analyzed.
bool followUsersOfUseIn(Attributor &A, const Use *U,
const Instruction *UserI);
/// Update the state according to the effect of use \p U in \p UserI.
void analyzeUseIn(Attributor &A, const Use *U, const Instruction *UserI);
protected:
/// Container for (transitive) uses of the associated argument.
SetVector<const Use *> Uses;
};
/// Memory behavior attribute for function argument.
struct AAMemoryBehaviorArgument : AAMemoryBehaviorFloating {
AAMemoryBehaviorArgument(const IRPosition &IRP)
: AAMemoryBehaviorFloating(IRP) {}
/// See AbstractAttribute::initialize(...).
void initialize(Attributor &A) override {
intersectAssumedBits(BEST_STATE);
const IRPosition &IRP = getIRPosition();
// TODO: Make IgnoreSubsumingPositions a property of an IRAttribute so we
// can query it when we use has/getAttr. That would allow us to reuse the
// initialize of the base class here.
bool HasByVal =
IRP.hasAttr({Attribute::ByVal}, /* IgnoreSubsumingPositions */ true);
getKnownStateFromValue(IRP, getState(),
/* IgnoreSubsumingPositions */ HasByVal);
// Initialize the use vector with all direct uses of the associated value.
Argument *Arg = getAssociatedArgument();
if (!Arg || !Arg->getParent()->hasExactDefinition()) {
indicatePessimisticFixpoint();
} else {
// Initialize the use vector with all direct uses of the associated value.
for (const Use &U : Arg->uses())
Uses.insert(&U);
}
}
ChangeStatus manifest(Attributor &A) override {
// TODO: From readattrs.ll: "inalloca parameters are always
// considered written"
if (hasAttr({Attribute::InAlloca})) {
removeKnownBits(NO_WRITES);
removeAssumedBits(NO_WRITES);
}
return AAMemoryBehaviorFloating::manifest(A);
}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override {
if (isAssumedReadNone())
STATS_DECLTRACK_ARG_ATTR(readnone)
else if (isAssumedReadOnly())
STATS_DECLTRACK_ARG_ATTR(readonly)
else if (isAssumedWriteOnly())
STATS_DECLTRACK_ARG_ATTR(writeonly)
}
};
struct AAMemoryBehaviorCallSiteArgument final : AAMemoryBehaviorArgument {
AAMemoryBehaviorCallSiteArgument(const IRPosition &IRP)
: AAMemoryBehaviorArgument(IRP) {}
/// See AbstractAttribute::initialize(...).
void initialize(Attributor &A) override {
if (Argument *Arg = getAssociatedArgument()) {
if (Arg->hasByValAttr()) {
addKnownBits(NO_WRITES);
removeKnownBits(NO_READS);
removeAssumedBits(NO_READS);
}
} else {
}
AAMemoryBehaviorArgument::initialize(A);
}
/// See AbstractAttribute::updateImpl(...).
ChangeStatus updateImpl(Attributor &A) override {
// TODO: Once we have call site specific value information we can provide
// call site specific liveness liveness information and then it makes
// sense to specialize attributes for call sites arguments instead of
// redirecting requests to the callee argument.
Argument *Arg = getAssociatedArgument();
const IRPosition &ArgPos = IRPosition::argument(*Arg);
auto &ArgAA = A.getAAFor<AAMemoryBehavior>(*this, ArgPos);
return clampStateAndIndicateChange(
getState(),
static_cast<const AAMemoryBehavior::StateType &>(ArgAA.getState()));
}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override {
if (isAssumedReadNone())
STATS_DECLTRACK_CSARG_ATTR(readnone)
else if (isAssumedReadOnly())
STATS_DECLTRACK_CSARG_ATTR(readonly)
else if (isAssumedWriteOnly())
STATS_DECLTRACK_CSARG_ATTR(writeonly)
}
};
/// Memory behavior attribute for a call site return position.
struct AAMemoryBehaviorCallSiteReturned final : AAMemoryBehaviorFloating {
AAMemoryBehaviorCallSiteReturned(const IRPosition &IRP)
: AAMemoryBehaviorFloating(IRP) {}
/// See AbstractAttribute::manifest(...).
ChangeStatus manifest(Attributor &A) override {
// We do not annotate returned values.
return ChangeStatus::UNCHANGED;
}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override {}
};
/// An AA to represent the memory behavior function attributes.
struct AAMemoryBehaviorFunction final : public AAMemoryBehaviorImpl {
AAMemoryBehaviorFunction(const IRPosition &IRP) : AAMemoryBehaviorImpl(IRP) {}
/// See AbstractAttribute::updateImpl(Attributor &A).
virtual ChangeStatus updateImpl(Attributor &A) override;
/// See AbstractAttribute::manifest(...).
ChangeStatus manifest(Attributor &A) override {
Function &F = cast<Function>(getAnchorValue());
if (isAssumedReadNone()) {
F.removeFnAttr(Attribute::ArgMemOnly);
F.removeFnAttr(Attribute::InaccessibleMemOnly);
F.removeFnAttr(Attribute::InaccessibleMemOrArgMemOnly);
}
return AAMemoryBehaviorImpl::manifest(A);
}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override {
if (isAssumedReadNone())
STATS_DECLTRACK_FN_ATTR(readnone)
else if (isAssumedReadOnly())
STATS_DECLTRACK_FN_ATTR(readonly)
else if (isAssumedWriteOnly())
STATS_DECLTRACK_FN_ATTR(writeonly)
}
};
/// AAMemoryBehavior attribute for call sites.
struct AAMemoryBehaviorCallSite final : AAMemoryBehaviorImpl {
AAMemoryBehaviorCallSite(const IRPosition &IRP) : AAMemoryBehaviorImpl(IRP) {}
/// See AbstractAttribute::initialize(...).
void initialize(Attributor &A) override {
AAMemoryBehaviorImpl::initialize(A);
Function *F = getAssociatedFunction();
if (!F || !F->hasExactDefinition())
indicatePessimisticFixpoint();
}
/// See AbstractAttribute::updateImpl(...).
ChangeStatus updateImpl(Attributor &A) override {
// TODO: Once we have call site specific value information we can provide
// call site specific liveness liveness information and then it makes
// sense to specialize attributes for call sites arguments instead of
// redirecting requests to the callee argument.
Function *F = getAssociatedFunction();
const IRPosition &FnPos = IRPosition::function(*F);
auto &FnAA = A.getAAFor<AAMemoryBehavior>(*this, FnPos);
return clampStateAndIndicateChange(
getState(),
static_cast<const AAMemoryBehavior::StateType &>(FnAA.getState()));
}
/// See AbstractAttribute::trackStatistics()
void trackStatistics() const override {
if (isAssumedReadNone())
STATS_DECLTRACK_CS_ATTR(readnone)
else if (isAssumedReadOnly())
STATS_DECLTRACK_CS_ATTR(readonly)
else if (isAssumedWriteOnly())
STATS_DECLTRACK_CS_ATTR(writeonly)
}
};
} // namespace
ChangeStatus AAMemoryBehaviorFunction::updateImpl(Attributor &A) {
// The current assumed state used to determine a change.
auto AssumedState = getAssumed();
auto CheckRWInst = [&](Instruction &I) {
// If the instruction has an own memory behavior state, use it to restrict
// the local state. No further analysis is required as the other memory
// state is as optimistic as it gets.
if (ImmutableCallSite ICS = ImmutableCallSite(&I)) {
const auto &MemBehaviorAA = A.getAAFor<AAMemoryBehavior>(
*this, IRPosition::callsite_function(ICS));
intersectAssumedBits(MemBehaviorAA.getAssumed());
return !isAtFixpoint();
}
// Remove access kind modifiers if necessary.
if (I.mayReadFromMemory())
removeAssumedBits(NO_READS);
if (I.mayWriteToMemory())
removeAssumedBits(NO_WRITES);
return !isAtFixpoint();
};
if (!A.checkForAllReadWriteInstructions(CheckRWInst, *this))
return indicatePessimisticFixpoint();
return (AssumedState != getAssumed()) ? ChangeStatus::CHANGED
: ChangeStatus::UNCHANGED;
}
ChangeStatus AAMemoryBehaviorFloating::updateImpl(Attributor &A) {
const IRPosition &IRP = getIRPosition();
const IRPosition &FnPos = IRPosition::function_scope(IRP);
AAMemoryBehavior::StateType &S = getState();
// First, check the function scope. We take the known information and we avoid
// work if the assumed information implies the current assumed information for
// this attribute. This is a valid for all but byval arguments.
Argument *Arg = IRP.getAssociatedArgument();
AAMemoryBehavior::base_t FnMemAssumedState =
AAMemoryBehavior::StateType::getWorstState();
if (!Arg || !Arg->hasByValAttr()) {
const auto &FnMemAA = A.getAAFor<AAMemoryBehavior>(*this, FnPos);
FnMemAssumedState = FnMemAA.getAssumed();
S.addKnownBits(FnMemAA.getKnown());
if ((S.getAssumed() & FnMemAA.getAssumed()) == S.getAssumed())
return ChangeStatus::UNCHANGED;
}
// Make sure the value is not captured (except through "return"), if
// it is, any information derived would be irrelevant anyway as we cannot
// check the potential aliases introduced by the capture. However, no need
// to fall back to anythign less optimistic than the function state.
const auto &ArgNoCaptureAA = A.getAAFor<AANoCapture>(
*this, IRP, /* TrackDependence */ true, DepClassTy::OPTIONAL);
if (!ArgNoCaptureAA.isAssumedNoCaptureMaybeReturned()) {
S.intersectAssumedBits(FnMemAssumedState);
return ChangeStatus::CHANGED;
}
// The current assumed state used to determine a change.
auto AssumedState = S.getAssumed();
// Liveness information to exclude dead users.
// TODO: Take the FnPos once we have call site specific liveness information.
const auto &LivenessAA = A.getAAFor<AAIsDead>(
*this, IRPosition::function(*IRP.getAssociatedFunction()));
// Visit and expand uses until all are analyzed or a fixpoint is reached.
for (unsigned i = 0; i < Uses.size() && !isAtFixpoint(); i++) {
const Use *U = Uses[i];
Instruction *UserI = cast<Instruction>(U->getUser());
LLVM_DEBUG(dbgs() << "[AAMemoryBehavior] Use: " << **U << " in " << *UserI
<< " [Dead: " << (LivenessAA.isAssumedDead(UserI))
<< "]\n");
if (LivenessAA.isAssumedDead(UserI))
continue;
// Check if the users of UserI should also be visited.
if (followUsersOfUseIn(A, U, UserI))
for (const Use &UserIUse : UserI->uses())
Uses.insert(&UserIUse);
// If UserI might touch memory we analyze the use in detail.
if (UserI->mayReadOrWriteMemory())
analyzeUseIn(A, U, UserI);
}
return (AssumedState != getAssumed()) ? ChangeStatus::CHANGED
: ChangeStatus::UNCHANGED;
}
bool AAMemoryBehaviorFloating::followUsersOfUseIn(Attributor &A, const Use *U,
const Instruction *UserI) {
// The loaded value is unrelated to the pointer argument, no need to
// follow the users of the load.
if (isa<LoadInst>(UserI))
return false;
// By default we follow all uses assuming UserI might leak information on U,
// we have special handling for call sites operands though.
ImmutableCallSite ICS(UserI);
if (!ICS || !ICS.isArgOperand(U))
return true;
// If the use is a call argument known not to be captured, the users of
// the call do not need to be visited because they have to be unrelated to
// the input. Note that this check is not trivial even though we disallow
// general capturing of the underlying argument. The reason is that the
// call might the argument "through return", which we allow and for which we
// need to check call users.
unsigned ArgNo = ICS.getArgumentNo(U);
const auto &ArgNoCaptureAA =
A.getAAFor<AANoCapture>(*this, IRPosition::callsite_argument(ICS, ArgNo));
return !ArgNoCaptureAA.isAssumedNoCapture();
}
void AAMemoryBehaviorFloating::analyzeUseIn(Attributor &A, const Use *U,
const Instruction *UserI) {
assert(UserI->mayReadOrWriteMemory());
switch (UserI->getOpcode()) {
default:
// TODO: Handle all atomics and other side-effect operations we know of.
break;
case Instruction::Load:
// Loads cause the NO_READS property to disappear.
removeAssumedBits(NO_READS);
return;
case Instruction::Store:
// Stores cause the NO_WRITES property to disappear if the use is the
// pointer operand. Note that we do assume that capturing was taken care of
// somewhere else.
if (cast<StoreInst>(UserI)->getPointerOperand() == U->get())
removeAssumedBits(NO_WRITES);
return;
case Instruction::Call:
case Instruction::CallBr:
case Instruction::Invoke: {
// For call sites we look at the argument memory behavior attribute (this
// could be recursive!) in order to restrict our own state.
ImmutableCallSite ICS(UserI);
// Give up on operand bundles.
if (ICS.isBundleOperand(U)) {
indicatePessimisticFixpoint();
return;
}
// Calling a function does read the function pointer, maybe write it if the
// function is self-modifying.
if (ICS.isCallee(U)) {
removeAssumedBits(NO_READS);
break;
}
// Adjust the possible access behavior based on the information on the
// argument.
unsigned ArgNo = ICS.getArgumentNo(U);
const IRPosition &ArgPos = IRPosition::callsite_argument(ICS, ArgNo);
const auto &MemBehaviorAA = A.getAAFor<AAMemoryBehavior>(*this, ArgPos);
// "assumed" has at most the same bits as the MemBehaviorAA assumed
// and at least "known".
intersectAssumedBits(MemBehaviorAA.getAssumed());
return;
}
};
// Generally, look at the "may-properties" and adjust the assumed state if we
// did not trigger special handling before.
if (UserI->mayReadFromMemory())
removeAssumedBits(NO_READS);
if (UserI->mayWriteToMemory())
removeAssumedBits(NO_WRITES);
}
/// ----------------------------------------------------------------------------
/// Attributor
/// ----------------------------------------------------------------------------
bool Attributor::isAssumedDead(const AbstractAttribute &AA,
const AAIsDead *LivenessAA) {
const Instruction *CtxI = AA.getIRPosition().getCtxI();
if (!CtxI)
return false;
// TODO: Find a good way to utilize fine and coarse grained liveness
// information.
if (!LivenessAA)
LivenessAA =
&getAAFor<AAIsDead>(AA, IRPosition::function(*CtxI->getFunction()),
/* TrackDependence */ false);
// Don't check liveness for AAIsDead.
if (&AA == LivenessAA)
return false;
if (!LivenessAA->isAssumedDead(CtxI))
return false;
// We actually used liveness information so we have to record a dependence.
recordDependence(*LivenessAA, AA, DepClassTy::OPTIONAL);
return true;
}
bool Attributor::checkForAllUses(
const function_ref<bool(const Use &, bool &)> &Pred,
const AbstractAttribute &QueryingAA, const Value &V) {
const IRPosition &IRP = QueryingAA.getIRPosition();
SmallVector<const Use *, 16> Worklist;
SmallPtrSet<const Use *, 16> Visited;
for (const Use &U : V.uses())
Worklist.push_back(&U);
LLVM_DEBUG(dbgs() << "[Attributor] Got " << Worklist.size()
<< " initial uses to check\n");
if (Worklist.empty())
return true;
bool AnyDead = false;
const Function *ScopeFn = IRP.getAnchorScope();
const auto *LivenessAA =
ScopeFn ? &getAAFor<AAIsDead>(QueryingAA, IRPosition::function(*ScopeFn),
/* TrackDependence */ false)
: nullptr;
while (!Worklist.empty()) {
const Use *U = Worklist.pop_back_val();
if (!Visited.insert(U).second)
continue;
LLVM_DEBUG(dbgs() << "[Attributor] Check use: " << **U << "\n");
if (Instruction *UserI = dyn_cast<Instruction>(U->getUser()))
if (LivenessAA && LivenessAA->isAssumedDead(UserI)) {
LLVM_DEBUG(dbgs() << "[Attributor] Dead user: " << *UserI << ": "
<< *LivenessAA << "\n");
AnyDead = true;
continue;
}
bool Follow = false;
if (!Pred(*U, Follow))
return false;
if (!Follow)
continue;
for (const Use &UU : U->getUser()->uses())
Worklist.push_back(&UU);
}
if (AnyDead)
recordDependence(*LivenessAA, QueryingAA, DepClassTy::OPTIONAL);
return true;
}
bool Attributor::checkForAllCallSites(
const function_ref<bool(AbstractCallSite)> &Pred,
const AbstractAttribute &QueryingAA, bool RequireAllCallSites) {
// We can try to determine information from
// the call sites. However, this is only possible all call sites are known,
// hence the function has internal linkage.
const IRPosition &IRP = QueryingAA.getIRPosition();
const Function *AssociatedFunction = IRP.getAssociatedFunction();
if (!AssociatedFunction) {
LLVM_DEBUG(dbgs() << "[Attributor] No function associated with " << IRP
<< "\n");
return false;
}
return checkForAllCallSites(Pred, *AssociatedFunction, RequireAllCallSites,
&QueryingAA);
}
bool Attributor::checkForAllCallSites(
const function_ref<bool(AbstractCallSite)> &Pred, const Function &Fn,
bool RequireAllCallSites, const AbstractAttribute *QueryingAA) {
if (RequireAllCallSites && !Fn.hasLocalLinkage()) {
LLVM_DEBUG(
dbgs()
<< "[Attributor] Function " << Fn.getName()
<< " has no internal linkage, hence not all call sites are known\n");
return false;
}
for (const Use &U : Fn.uses()) {
AbstractCallSite ACS(&U);
if (!ACS) {
LLVM_DEBUG(dbgs() << "[Attributor] Function " << Fn.getName()
<< " has non call site use " << *U.get() << " in "
<< *U.getUser() << "\n");
// BlockAddress users are allowed.
if (isa<BlockAddress>(U.getUser()))
continue;
return false;
}
Instruction *I = ACS.getInstruction();
Function *Caller = I->getFunction();
const auto *LivenessAA =
lookupAAFor<AAIsDead>(IRPosition::function(*Caller), QueryingAA,
/* TrackDependence */ false);
// Skip dead calls.
if (LivenessAA && LivenessAA->isAssumedDead(I)) {
// We actually used liveness information so we have to record a
// dependence.
if (QueryingAA)
recordDependence(*LivenessAA, *QueryingAA, DepClassTy::OPTIONAL);
continue;
}
const Use *EffectiveUse =
ACS.isCallbackCall() ? &ACS.getCalleeUseForCallback() : &U;
if (!ACS.isCallee(EffectiveUse)) {
if (!RequireAllCallSites)
continue;
LLVM_DEBUG(dbgs() << "[Attributor] User " << EffectiveUse->getUser()
<< " is an invalid use of " << Fn.getName() << "\n");
return false;
}
if (Pred(ACS))
continue;
LLVM_DEBUG(dbgs() << "[Attributor] Call site callback failed for "
<< *ACS.getInstruction() << "\n");
return false;
}
return true;
}
bool Attributor::checkForAllReturnedValuesAndReturnInsts(
const function_ref<bool(Value &, const SmallSetVector<ReturnInst *, 4> &)>
&Pred,
const AbstractAttribute &QueryingAA) {
const IRPosition &IRP = QueryingAA.getIRPosition();
// Since we need to provide return instructions we have to have an exact
// definition.
const Function *AssociatedFunction = IRP.getAssociatedFunction();
if (!AssociatedFunction)
return false;
// If this is a call site query we use the call site specific return values
// and liveness information.
// TODO: use the function scope once we have call site AAReturnedValues.
const IRPosition &QueryIRP = IRPosition::function(*AssociatedFunction);
const auto &AARetVal = getAAFor<AAReturnedValues>(QueryingAA, QueryIRP);
if (!AARetVal.getState().isValidState())
return false;
return AARetVal.checkForAllReturnedValuesAndReturnInsts(Pred);
}
bool Attributor::checkForAllReturnedValues(
const function_ref<bool(Value &)> &Pred,
const AbstractAttribute &QueryingAA) {
const IRPosition &IRP = QueryingAA.getIRPosition();
const Function *AssociatedFunction = IRP.getAssociatedFunction();
if (!AssociatedFunction)
return false;
// TODO: use the function scope once we have call site AAReturnedValues.
const IRPosition &QueryIRP = IRPosition::function(*AssociatedFunction);
const auto &AARetVal = getAAFor<AAReturnedValues>(QueryingAA, QueryIRP);
if (!AARetVal.getState().isValidState())
return false;
return AARetVal.checkForAllReturnedValuesAndReturnInsts(
[&](Value &RV, const SmallSetVector<ReturnInst *, 4> &) {
return Pred(RV);
});
}
static bool
checkForAllInstructionsImpl(InformationCache::OpcodeInstMapTy &OpcodeInstMap,
const function_ref<bool(Instruction &)> &Pred,
const AAIsDead *LivenessAA, bool &AnyDead,
const ArrayRef<unsigned> &Opcodes) {
for (unsigned Opcode : Opcodes) {
for (Instruction *I : OpcodeInstMap[Opcode]) {
// Skip dead instructions.
if (LivenessAA && LivenessAA->isAssumedDead(I)) {
AnyDead = true;
continue;
}
if (!Pred(*I))
return false;
}
}
return true;
}
bool Attributor::checkForAllInstructions(
const llvm::function_ref<bool(Instruction &)> &Pred,
const AbstractAttribute &QueryingAA, const ArrayRef<unsigned> &Opcodes) {
const IRPosition &IRP = QueryingAA.getIRPosition();
// Since we need to provide instructions we have to have an exact definition.
const Function *AssociatedFunction = IRP.getAssociatedFunction();
if (!AssociatedFunction)
return false;
// TODO: use the function scope once we have call site AAReturnedValues.
const IRPosition &QueryIRP = IRPosition::function(*AssociatedFunction);
const auto &LivenessAA =
getAAFor<AAIsDead>(QueryingAA, QueryIRP, /* TrackDependence */ false);
bool AnyDead = false;
auto &OpcodeInstMap =
InfoCache.getOpcodeInstMapForFunction(*AssociatedFunction);
if (!checkForAllInstructionsImpl(OpcodeInstMap, Pred, &LivenessAA, AnyDead,
Opcodes))
return false;
// If we actually used liveness information so we have to record a dependence.
if (AnyDead)
recordDependence(LivenessAA, QueryingAA, DepClassTy::OPTIONAL);
return true;
}
bool Attributor::checkForAllReadWriteInstructions(
const llvm::function_ref<bool(Instruction &)> &Pred,
AbstractAttribute &QueryingAA) {
const Function *AssociatedFunction =
QueryingAA.getIRPosition().getAssociatedFunction();
if (!AssociatedFunction)
return false;
// TODO: use the function scope once we have call site AAReturnedValues.
const IRPosition &QueryIRP = IRPosition::function(*AssociatedFunction);
const auto &LivenessAA =
getAAFor<AAIsDead>(QueryingAA, QueryIRP, /* TrackDependence */ false);
bool AnyDead = false;
for (Instruction *I :
InfoCache.getReadOrWriteInstsForFunction(*AssociatedFunction)) {
// Skip dead instructions.
if (LivenessAA.isAssumedDead(I)) {
AnyDead = true;
continue;
}
if (!Pred(*I))
return false;
}
// If we actually used liveness information so we have to record a dependence.
if (AnyDead)
recordDependence(LivenessAA, QueryingAA, DepClassTy::OPTIONAL);
return true;
}
ChangeStatus Attributor::run(Module &M) {
LLVM_DEBUG(dbgs() << "[Attributor] Identified and initialized "
<< AllAbstractAttributes.size()
<< " abstract attributes.\n");
// Now that all abstract attributes are collected and initialized we start
// the abstract analysis.
unsigned IterationCounter = 1;
SmallVector<AbstractAttribute *, 64> ChangedAAs;
SetVector<AbstractAttribute *> Worklist, InvalidAAs;
Worklist.insert(AllAbstractAttributes.begin(), AllAbstractAttributes.end());
bool RecomputeDependences = false;
do {
// Remember the size to determine new attributes.
size_t NumAAs = AllAbstractAttributes.size();
LLVM_DEBUG(dbgs() << "\n\n[Attributor] #Iteration: " << IterationCounter
<< ", Worklist size: " << Worklist.size() << "\n");
// For invalid AAs we can fix dependent AAs that have a required dependence,
// thereby folding long dependence chains in a single step without the need
// to run updates.
for (unsigned u = 0; u < InvalidAAs.size(); ++u) {
AbstractAttribute *InvalidAA = InvalidAAs[u];
auto &QuerriedAAs = QueryMap[InvalidAA];
LLVM_DEBUG(dbgs() << "[Attributor] InvalidAA: " << *InvalidAA << " has "
<< QuerriedAAs.RequiredAAs.size() << "/"
<< QuerriedAAs.OptionalAAs.size()
<< " required/optional dependences\n");
for (AbstractAttribute *DepOnInvalidAA : QuerriedAAs.RequiredAAs) {
AbstractState &DOIAAState = DepOnInvalidAA->getState();
DOIAAState.indicatePessimisticFixpoint();
++NumAttributesFixedDueToRequiredDependences;
assert(DOIAAState.isAtFixpoint() && "Expected fixpoint state!");
if (!DOIAAState.isValidState())
InvalidAAs.insert(DepOnInvalidAA);
}
if (!RecomputeDependences)
Worklist.insert(QuerriedAAs.OptionalAAs.begin(),
QuerriedAAs.OptionalAAs.end());
}
// If dependences (=QueryMap) are recomputed we have to look at all abstract
// attributes again, regardless of what changed in the last iteration.
if (RecomputeDependences) {
LLVM_DEBUG(
dbgs() << "[Attributor] Run all AAs to recompute dependences\n");
QueryMap.clear();
ChangedAAs.clear();
Worklist.insert(AllAbstractAttributes.begin(),
AllAbstractAttributes.end());
}
// Add all abstract attributes that are potentially dependent on one that
// changed to the work list.
for (AbstractAttribute *ChangedAA : ChangedAAs) {
auto &QuerriedAAs = QueryMap[ChangedAA];
Worklist.insert(QuerriedAAs.OptionalAAs.begin(),
QuerriedAAs.OptionalAAs.end());
Worklist.insert(QuerriedAAs.RequiredAAs.begin(),
QuerriedAAs.RequiredAAs.end());
}
LLVM_DEBUG(dbgs() << "[Attributor] #Iteration: " << IterationCounter
<< ", Worklist+Dependent size: " << Worklist.size()
<< "\n");
// Reset the changed and invalid set.
ChangedAAs.clear();
InvalidAAs.clear();
// Update all abstract attribute in the work list and record the ones that
// changed.
for (AbstractAttribute *AA : Worklist)
if (!AA->getState().isAtFixpoint() && !isAssumedDead(*AA, nullptr)) {
QueriedNonFixAA = false;
if (AA->update(*this) == ChangeStatus::CHANGED) {
ChangedAAs.push_back(AA);
if (!AA->getState().isValidState())
InvalidAAs.insert(AA);
} else if (!QueriedNonFixAA) {
// If the attribute did not query any non-fix information, the state
// will not change and we can indicate that right away.
AA->getState().indicateOptimisticFixpoint();
}
}
// Check if we recompute the dependences in the next iteration.
RecomputeDependences = (DepRecomputeInterval > 0 &&
IterationCounter % DepRecomputeInterval == 0);
// Add attributes to the changed set if they have been created in the last
// iteration.
ChangedAAs.append(AllAbstractAttributes.begin() + NumAAs,
AllAbstractAttributes.end());
// Reset the work list and repopulate with the changed abstract attributes.
// Note that dependent ones are added above.
Worklist.clear();
Worklist.insert(ChangedAAs.begin(), ChangedAAs.end());
} while (!Worklist.empty() && (IterationCounter++ < MaxFixpointIterations ||
VerifyMaxFixpointIterations));
LLVM_DEBUG(dbgs() << "\n[Attributor] Fixpoint iteration done after: "
<< IterationCounter << "/" << MaxFixpointIterations
<< " iterations\n");
size_t NumFinalAAs = AllAbstractAttributes.size();
// Reset abstract arguments not settled in a sound fixpoint by now. This
// happens when we stopped the fixpoint iteration early. Note that only the
// ones marked as "changed" *and* the ones transitively depending on them
// need to be reverted to a pessimistic state. Others might not be in a
// fixpoint state but we can use the optimistic results for them anyway.
SmallPtrSet<AbstractAttribute *, 32> Visited;
for (unsigned u = 0; u < ChangedAAs.size(); u++) {
AbstractAttribute *ChangedAA = ChangedAAs[u];
if (!Visited.insert(ChangedAA).second)
continue;
AbstractState &State = ChangedAA->getState();
if (!State.isAtFixpoint()) {
State.indicatePessimisticFixpoint();
NumAttributesTimedOut++;
}
auto &QuerriedAAs = QueryMap[ChangedAA];
ChangedAAs.append(QuerriedAAs.OptionalAAs.begin(),
QuerriedAAs.OptionalAAs.end());
ChangedAAs.append(QuerriedAAs.RequiredAAs.begin(),
QuerriedAAs.RequiredAAs.end());
}
LLVM_DEBUG({
if (!Visited.empty())
dbgs() << "\n[Attributor] Finalized " << Visited.size()
<< " abstract attributes.\n";
});
unsigned NumManifested = 0;
unsigned NumAtFixpoint = 0;
ChangeStatus ManifestChange = ChangeStatus::UNCHANGED;
for (AbstractAttribute *AA : AllAbstractAttributes) {
AbstractState &State = AA->getState();
// If there is not already a fixpoint reached, we can now take the
// optimistic state. This is correct because we enforced a pessimistic one
// on abstract attributes that were transitively dependent on a changed one
// already above.
if (!State.isAtFixpoint())
State.indicateOptimisticFixpoint();
// If the state is invalid, we do not try to manifest it.
if (!State.isValidState())
continue;
// Skip dead code.
if (isAssumedDead(*AA, nullptr))
continue;
// Manifest the state and record if we changed the IR.
ChangeStatus LocalChange = AA->manifest(*this);
if (LocalChange == ChangeStatus::CHANGED && AreStatisticsEnabled())
AA->trackStatistics();
ManifestChange = ManifestChange | LocalChange;
NumAtFixpoint++;
NumManifested += (LocalChange == ChangeStatus::CHANGED);
}
(void)NumManifested;
(void)NumAtFixpoint;
LLVM_DEBUG(dbgs() << "\n[Attributor] Manifested " << NumManifested
<< " arguments while " << NumAtFixpoint
<< " were in a valid fixpoint state\n");
NumAttributesManifested += NumManifested;
NumAttributesValidFixpoint += NumAtFixpoint;
(void)NumFinalAAs;
assert(
NumFinalAAs == AllAbstractAttributes.size() &&
"Expected the final number of abstract attributes to remain unchanged!");
// Delete stuff at the end to avoid invalid references and a nice order.
{
LLVM_DEBUG(dbgs() << "\n[Attributor] Delete at least "
<< ToBeDeletedFunctions.size() << " functions and "
<< ToBeDeletedBlocks.size() << " blocks and "
<< ToBeDeletedInsts.size() << " instructions and "
<< ToBeChangedUses.size() << " uses\n");
SmallVector<Instruction *, 32> DeadInsts;
SmallVector<Instruction *, 32> TerminatorsToFold;
for (auto &It : ToBeChangedUses) {
Use *U = It.first;
Value *NewV = It.second;
Value *OldV = U->get();
LLVM_DEBUG(dbgs() << "Use " << *NewV << " in " << *U->getUser()
<< " instead of " << *OldV << "\n");
U->set(NewV);
if (Instruction *I = dyn_cast<Instruction>(OldV))
if (!isa<PHINode>(I) && !ToBeDeletedInsts.count(I) &&
isInstructionTriviallyDead(I)) {
DeadInsts.push_back(I);
}
if (isa<Constant>(NewV) && isa<BranchInst>(U->getUser())) {
Instruction *UserI = cast<Instruction>(U->getUser());
if (isa<UndefValue>(NewV)) {
ToBeChangedToUnreachableInsts.insert(UserI);
} else {
TerminatorsToFold.push_back(UserI);
}
}
}
for (Instruction *I : ToBeChangedToUnreachableInsts)
changeToUnreachable(I, /* UseLLVMTrap */ false);
for (Instruction *I : TerminatorsToFold)
ConstantFoldTerminator(I->getParent());
for (Instruction *I : ToBeDeletedInsts) {
I->replaceAllUsesWith(UndefValue::get(I->getType()));
if (!isa<PHINode>(I) && isInstructionTriviallyDead(I))
DeadInsts.push_back(I);
else
I->eraseFromParent();
}
RecursivelyDeleteTriviallyDeadInstructions(DeadInsts);
if (unsigned NumDeadBlocks = ToBeDeletedBlocks.size()) {
SmallVector<BasicBlock *, 8> ToBeDeletedBBs;
ToBeDeletedBBs.reserve(NumDeadBlocks);
ToBeDeletedBBs.append(ToBeDeletedBlocks.begin(), ToBeDeletedBlocks.end());
// Actually we do not delete the blocks but squash them into a single
// unreachable but untangling branches that jump here is something we need
// to do in a more generic way.
DetatchDeadBlocks(ToBeDeletedBBs, nullptr);
STATS_DECL(AAIsDead, BasicBlock, "Number of dead basic blocks deleted.");
BUILD_STAT_NAME(AAIsDead, BasicBlock) += ToBeDeletedBlocks.size();
}
// Identify dead internal functions and delete them. This happens outside
// the other fixpoint analysis as we might treat potentially dead functions
// as live to lower the number of iterations. If they happen to be dead, the
// below fixpoint loop will identify and eliminate them.
SmallVector<Function *, 8> InternalFns;
for (Function &F : M)
if (F.hasLocalLinkage())
InternalFns.push_back(&F);
bool FoundDeadFn = true;
while (FoundDeadFn) {
FoundDeadFn = false;
for (unsigned u = 0, e = InternalFns.size(); u < e; ++u) {
Function *F = InternalFns[u];
if (!F)
continue;
if (!checkForAllCallSites(
[this](AbstractCallSite ACS) {
return ToBeDeletedFunctions.count(
ACS.getInstruction()->getFunction());
},
*F, true, nullptr))
continue;
ToBeDeletedFunctions.insert(F);
InternalFns[u] = nullptr;
FoundDeadFn = true;
}
}
}
STATS_DECL(AAIsDead, Function, "Number of dead functions deleted.");
BUILD_STAT_NAME(AAIsDead, Function) += ToBeDeletedFunctions.size();
// Rewrite the functions as requested during manifest.
ManifestChange = ManifestChange | rewriteFunctionSignatures();
for (Function *Fn : ToBeDeletedFunctions) {
Fn->deleteBody();
Fn->replaceAllUsesWith(UndefValue::get(Fn->getType()));
Fn->eraseFromParent();
}
if (VerifyMaxFixpointIterations &&
IterationCounter != MaxFixpointIterations) {
errs() << "\n[Attributor] Fixpoint iteration done after: "
<< IterationCounter << "/" << MaxFixpointIterations
<< " iterations\n";
llvm_unreachable("The fixpoint was not reached with exactly the number of "
"specified iterations!");
}
return ManifestChange;
}
bool Attributor::registerFunctionSignatureRewrite(
Argument &Arg, ArrayRef<Type *> ReplacementTypes,
ArgumentReplacementInfo::CalleeRepairCBTy &&CalleeRepairCB,
ArgumentReplacementInfo::ACSRepairCBTy &&ACSRepairCB) {
auto CallSiteCanBeChanged = [](AbstractCallSite ACS) {
// Forbid must-tail calls for now.
return !ACS.isCallbackCall() && !ACS.getCallSite().isMustTailCall();
};
Function *Fn = Arg.getParent();
// Avoid var-arg functions for now.
if (Fn->isVarArg()) {
LLVM_DEBUG(dbgs() << "[Attributor] Cannot rewrite var-args functions\n");
return false;
}
// Avoid functions with complicated argument passing semantics.
AttributeList FnAttributeList = Fn->getAttributes();
if (FnAttributeList.hasAttrSomewhere(Attribute::Nest) ||
FnAttributeList.hasAttrSomewhere(Attribute::StructRet) ||
FnAttributeList.hasAttrSomewhere(Attribute::InAlloca)) {
LLVM_DEBUG(
dbgs() << "[Attributor] Cannot rewrite due to complex attribute\n");
return false;
}
// Avoid callbacks for now.
if (!checkForAllCallSites(CallSiteCanBeChanged, *Fn, true, nullptr)) {
LLVM_DEBUG(dbgs() << "[Attributor] Cannot rewrite all call sites\n");
return false;
}
auto InstPred = [](Instruction &I) {
if (auto *CI = dyn_cast<CallInst>(&I))
return !CI->isMustTailCall();
return true;
};
// Forbid must-tail calls for now.
// TODO:
bool AnyDead;
auto &OpcodeInstMap = InfoCache.getOpcodeInstMapForFunction(*Fn);
if (!checkForAllInstructionsImpl(OpcodeInstMap, InstPred, nullptr, AnyDead,
{Instruction::Call})) {
LLVM_DEBUG(dbgs() << "[Attributor] Cannot rewrite due to instructions\n");
return false;
}
SmallVectorImpl<ArgumentReplacementInfo *> &ARIs = ArgumentReplacementMap[Fn];
if (ARIs.size() == 0)
ARIs.resize(Fn->arg_size());
// If we have a replacement already with less than or equal new arguments,
// ignore this request.
ArgumentReplacementInfo *&ARI = ARIs[Arg.getArgNo()];
if (ARI && ARI->getNumReplacementArgs() <= ReplacementTypes.size()) {
LLVM_DEBUG(dbgs() << "[Attributor] Existing rewrite is preferred\n");
return false;
}
// If we have a replacement already but we like the new one better, delete
// the old.
if (ARI)
delete ARI;
// Remember the replacement.
ARI = new ArgumentReplacementInfo(*this, Arg, ReplacementTypes,
std::move(CalleeRepairCB),
std::move(ACSRepairCB));
return true;
}
ChangeStatus Attributor::rewriteFunctionSignatures() {
ChangeStatus Changed = ChangeStatus::UNCHANGED;
for (auto &It : ArgumentReplacementMap) {
Function *OldFn = It.getFirst();
// Deleted functions do not require rewrites.
if (ToBeDeletedFunctions.count(OldFn))
continue;
const SmallVectorImpl<ArgumentReplacementInfo *> &ARIs = It.getSecond();
assert(ARIs.size() == OldFn->arg_size() && "Inconsistent state!");
SmallVector<Type *, 16> NewArgumentTypes;
SmallVector<AttributeSet, 16> NewArgumentAttributes;
// Collect replacement argument types and copy over existing attributes.
AttributeList OldFnAttributeList = OldFn->getAttributes();
for (Argument &Arg : OldFn->args()) {
if (ArgumentReplacementInfo *ARI = ARIs[Arg.getArgNo()]) {
NewArgumentTypes.append(ARI->ReplacementTypes.begin(),
ARI->ReplacementTypes.end());
NewArgumentAttributes.append(ARI->getNumReplacementArgs(),
AttributeSet());
} else {
NewArgumentTypes.push_back(Arg.getType());
NewArgumentAttributes.push_back(
OldFnAttributeList.getParamAttributes(Arg.getArgNo()));
}
}
FunctionType *OldFnTy = OldFn->getFunctionType();
Type *RetTy = OldFnTy->getReturnType();
// Construct the new function type using the new arguments types.
FunctionType *NewFnTy =
FunctionType::get(RetTy, NewArgumentTypes, OldFnTy->isVarArg());
LLVM_DEBUG(dbgs() << "[Attributor] Function rewrite '" << OldFn->getName()
<< "' from " << *OldFn->getFunctionType() << " to "
<< *NewFnTy << "\n");
// Create the new function body and insert it into the module.
Function *NewFn = Function::Create(NewFnTy, OldFn->getLinkage(),
OldFn->getAddressSpace(), "");
OldFn->getParent()->getFunctionList().insert(OldFn->getIterator(), NewFn);
NewFn->takeName(OldFn);
NewFn->copyAttributesFrom(OldFn);
// Patch the pointer to LLVM function in debug info descriptor.
NewFn->setSubprogram(OldFn->getSubprogram());
OldFn->setSubprogram(nullptr);
// Recompute the parameter attributes list based on the new arguments for
// the function.
LLVMContext &Ctx = OldFn->getContext();
NewFn->setAttributes(AttributeList::get(
Ctx, OldFnAttributeList.getFnAttributes(),
OldFnAttributeList.getRetAttributes(), NewArgumentAttributes));
// Since we have now created the new function, splice the body of the old
// function right into the new function, leaving the old rotting hulk of the
// function empty.
NewFn->getBasicBlockList().splice(NewFn->begin(),
OldFn->getBasicBlockList());
// Set of all "call-like" instructions that invoke the old function mapped
// to their new replacements.
SmallVector<std::pair<CallBase *, CallBase *>, 8> CallSitePairs;
// Callback to create a new "call-like" instruction for a given one.
auto CallSiteReplacementCreator = [&](AbstractCallSite ACS) {
CallBase *OldCB = cast<CallBase>(ACS.getInstruction());
const AttributeList &OldCallAttributeList = OldCB->getAttributes();
// Collect the new argument operands for the replacement call site.
SmallVector<Value *, 16> NewArgOperands;
SmallVector<AttributeSet, 16> NewArgOperandAttributes;
for (unsigned OldArgNum = 0; OldArgNum < ARIs.size(); ++OldArgNum) {
unsigned NewFirstArgNum = NewArgOperands.size();
(void)NewFirstArgNum; // only used inside assert.
if (ArgumentReplacementInfo *ARI = ARIs[OldArgNum]) {
if (ARI->ACSRepairCB)
ARI->ACSRepairCB(*ARI, ACS, NewArgOperands);
assert(ARI->getNumReplacementArgs() + NewFirstArgNum ==
NewArgOperands.size() &&
"ACS repair callback did not provide as many operand as new "
"types were registered!");
// TODO: Exose the attribute set to the ACS repair callback
NewArgOperandAttributes.append(ARI->ReplacementTypes.size(),
AttributeSet());
} else {
NewArgOperands.push_back(ACS.getCallArgOperand(OldArgNum));
NewArgOperandAttributes.push_back(
OldCallAttributeList.getParamAttributes(OldArgNum));
}
}
assert(NewArgOperands.size() == NewArgOperandAttributes.size() &&
"Mismatch # argument operands vs. # argument operand attributes!");
assert(NewArgOperands.size() == NewFn->arg_size() &&
"Mismatch # argument operands vs. # function arguments!");
SmallVector<OperandBundleDef, 4> OperandBundleDefs;
OldCB->getOperandBundlesAsDefs(OperandBundleDefs);
// Create a new call or invoke instruction to replace the old one.
CallBase *NewCB;
if (InvokeInst *II = dyn_cast<InvokeInst>(OldCB)) {
NewCB =
InvokeInst::Create(NewFn, II->getNormalDest(), II->getUnwindDest(),
NewArgOperands, OperandBundleDefs, "", OldCB);
} else {
auto *NewCI = CallInst::Create(NewFn, NewArgOperands, OperandBundleDefs,
"", OldCB);
NewCI->setTailCallKind(cast<CallInst>(OldCB)->getTailCallKind());
NewCB = NewCI;
}
// Copy over various properties and the new attributes.
uint64_t W;
if (OldCB->extractProfTotalWeight(W))
NewCB->setProfWeight(W);
NewCB->setCallingConv(OldCB->getCallingConv());
NewCB->setDebugLoc(OldCB->getDebugLoc());
NewCB->takeName(OldCB);
NewCB->setAttributes(AttributeList::get(
Ctx, OldCallAttributeList.getFnAttributes(),
OldCallAttributeList.getRetAttributes(), NewArgOperandAttributes));
CallSitePairs.push_back({OldCB, NewCB});
return true;
};
// Use the CallSiteReplacementCreator to create replacement call sites.
bool Success =
checkForAllCallSites(CallSiteReplacementCreator, *OldFn, true, nullptr);
(void)Success;
assert(Success && "Assumed call site replacement to succeed!");
// Rewire the arguments.
auto OldFnArgIt = OldFn->arg_begin();
auto NewFnArgIt = NewFn->arg_begin();
for (unsigned OldArgNum = 0; OldArgNum < ARIs.size();
++OldArgNum, ++OldFnArgIt) {
if (ArgumentReplacementInfo *ARI = ARIs[OldArgNum]) {
if (ARI->CalleeRepairCB)
ARI->CalleeRepairCB(*ARI, *NewFn, NewFnArgIt);
NewFnArgIt += ARI->ReplacementTypes.size();
} else {
NewFnArgIt->takeName(&*OldFnArgIt);
OldFnArgIt->replaceAllUsesWith(&*NewFnArgIt);
++NewFnArgIt;
}
}
// Eliminate the instructions *after* we visited all of them.
for (auto &CallSitePair : CallSitePairs) {
CallBase &OldCB = *CallSitePair.first;
CallBase &NewCB = *CallSitePair.second;
OldCB.replaceAllUsesWith(&NewCB);
OldCB.eraseFromParent();
}
ToBeDeletedFunctions.insert(OldFn);
Changed = ChangeStatus::CHANGED;
}
return Changed;
}
void Attributor::initializeInformationCache(Function &F) {
// Walk all instructions to find interesting instructions that might be
// queried by abstract attributes during their initialization or update.
// This has to happen before we create attributes.
auto &ReadOrWriteInsts = InfoCache.FuncRWInstsMap[&F];
auto &InstOpcodeMap = InfoCache.FuncInstOpcodeMap[&F];
for (Instruction &I : instructions(&F)) {
bool IsInterestingOpcode = false;
// To allow easy access to all instructions in a function with a given
// opcode we store them in the InfoCache. As not all opcodes are interesting
// to concrete attributes we only cache the ones that are as identified in
// the following switch.
// Note: There are no concrete attributes now so this is initially empty.
switch (I.getOpcode()) {
default:
assert((!ImmutableCallSite(&I)) && (!isa<CallBase>(&I)) &&
"New call site/base instruction type needs to be known int the "
"Attributor.");
break;
case Instruction::Load:
// The alignment of a pointer is interesting for loads.
case Instruction::Store:
// The alignment of a pointer is interesting for stores.
case Instruction::Call:
case Instruction::CallBr:
case Instruction::Invoke:
case Instruction::CleanupRet:
case Instruction::CatchSwitch:
case Instruction::AtomicRMW:
case Instruction::AtomicCmpXchg:
case Instruction::Br:
case Instruction::Resume:
case Instruction::Ret:
IsInterestingOpcode = true;
}
if (IsInterestingOpcode)
InstOpcodeMap[I.getOpcode()].push_back(&I);
if (I.mayReadOrWriteMemory())
ReadOrWriteInsts.push_back(&I);
}
}
void Attributor::recordDependence(const AbstractAttribute &FromAA,
const AbstractAttribute &ToAA,
DepClassTy DepClass) {
if (FromAA.getState().isAtFixpoint())
return;
if (DepClass == DepClassTy::REQUIRED)
QueryMap[&FromAA].RequiredAAs.insert(
const_cast<AbstractAttribute *>(&ToAA));
else
QueryMap[&FromAA].OptionalAAs.insert(
const_cast<AbstractAttribute *>(&ToAA));
QueriedNonFixAA = true;
}
void Attributor::identifyDefaultAbstractAttributes(Function &F) {
if (!VisitedFunctions.insert(&F).second)
return;
if (F.isDeclaration())
return;
IRPosition FPos = IRPosition::function(F);
// Check for dead BasicBlocks in every function.
// We need dead instruction detection because we do not want to deal with
// broken IR in which SSA rules do not apply.
getOrCreateAAFor<AAIsDead>(FPos);
// Every function might be "will-return".
getOrCreateAAFor<AAWillReturn>(FPos);
// Every function might contain instructions that cause "undefined behavior".
getOrCreateAAFor<AAUndefinedBehavior>(FPos);
// Every function can be nounwind.
getOrCreateAAFor<AANoUnwind>(FPos);
// Every function might be marked "nosync"
getOrCreateAAFor<AANoSync>(FPos);
// Every function might be "no-free".
getOrCreateAAFor<AANoFree>(FPos);
// Every function might be "no-return".
getOrCreateAAFor<AANoReturn>(FPos);
// Every function might be "no-recurse".
getOrCreateAAFor<AANoRecurse>(FPos);
// Every function might be "readnone/readonly/writeonly/...".
getOrCreateAAFor<AAMemoryBehavior>(FPos);
// Every function might be applicable for Heap-To-Stack conversion.
if (EnableHeapToStack)
getOrCreateAAFor<AAHeapToStack>(FPos);
// Return attributes are only appropriate if the return type is non void.
Type *ReturnType = F.getReturnType();
if (!ReturnType->isVoidTy()) {
// Argument attribute "returned" --- Create only one per function even
// though it is an argument attribute.
getOrCreateAAFor<AAReturnedValues>(FPos);
IRPosition RetPos = IRPosition::returned(F);
// Every returned value might be dead.
getOrCreateAAFor<AAIsDead>(RetPos);
// Every function might be simplified.
getOrCreateAAFor<AAValueSimplify>(RetPos);
if (ReturnType->isPointerTy()) {
// Every function with pointer return type might be marked align.
getOrCreateAAFor<AAAlign>(RetPos);
// Every function with pointer return type might be marked nonnull.
getOrCreateAAFor<AANonNull>(RetPos);
// Every function with pointer return type might be marked noalias.
getOrCreateAAFor<AANoAlias>(RetPos);
// Every function with pointer return type might be marked
// dereferenceable.
getOrCreateAAFor<AADereferenceable>(RetPos);
}
}
for (Argument &Arg : F.args()) {
IRPosition ArgPos = IRPosition::argument(Arg);
// Every argument might be simplified.
getOrCreateAAFor<AAValueSimplify>(ArgPos);
if (Arg.getType()->isPointerTy()) {
// Every argument with pointer type might be marked nonnull.
getOrCreateAAFor<AANonNull>(ArgPos);
// Every argument with pointer type might be marked noalias.
getOrCreateAAFor<AANoAlias>(ArgPos);
// Every argument with pointer type might be marked dereferenceable.
getOrCreateAAFor<AADereferenceable>(ArgPos);
// Every argument with pointer type might be marked align.
getOrCreateAAFor<AAAlign>(ArgPos);
// Every argument with pointer type might be marked nocapture.
getOrCreateAAFor<AANoCapture>(ArgPos);
// Every argument with pointer type might be marked
// "readnone/readonly/writeonly/..."
getOrCreateAAFor<AAMemoryBehavior>(ArgPos);
// Every argument with pointer type might be marked nofree.
getOrCreateAAFor<AANoFree>(ArgPos);
}
}
auto CallSitePred = [&](Instruction &I) -> bool {
CallSite CS(&I);
if (Function *Callee = CS.getCalledFunction()) {
// Skip declerations except if annotations on their call sites were
// explicitly requested.
if (!AnnotateDeclarationCallSites && Callee->isDeclaration() &&
!Callee->hasMetadata(LLVMContext::MD_callback))
return true;
if (!Callee->getReturnType()->isVoidTy() && !CS->use_empty()) {
IRPosition CSRetPos = IRPosition::callsite_returned(CS);
// Call site return values might be dead.
getOrCreateAAFor<AAIsDead>(CSRetPos);
}
for (int i = 0, e = CS.getNumArgOperands(); i < e; i++) {
IRPosition CSArgPos = IRPosition::callsite_argument(CS, i);
// Every call site argument might be dead.
getOrCreateAAFor<AAIsDead>(CSArgPos);
// Call site argument might be simplified.
getOrCreateAAFor<AAValueSimplify>(CSArgPos);
if (!CS.getArgument(i)->getType()->isPointerTy())
continue;
// Call site argument attribute "non-null".
getOrCreateAAFor<AANonNull>(CSArgPos);
// Call site argument attribute "no-alias".
getOrCreateAAFor<AANoAlias>(CSArgPos);
// Call site argument attribute "dereferenceable".
getOrCreateAAFor<AADereferenceable>(CSArgPos);
// Call site argument attribute "align".
getOrCreateAAFor<AAAlign>(CSArgPos);
// Call site argument attribute
// "readnone/readonly/writeonly/..."
getOrCreateAAFor<AAMemoryBehavior>(CSArgPos);
// Call site argument attribute "nofree".
getOrCreateAAFor<AANoFree>(CSArgPos);
}
}
return true;
};
auto &OpcodeInstMap = InfoCache.getOpcodeInstMapForFunction(F);
bool Success, AnyDead = false;
Success = checkForAllInstructionsImpl(
OpcodeInstMap, CallSitePred, nullptr, AnyDead,
{(unsigned)Instruction::Invoke, (unsigned)Instruction::CallBr,
(unsigned)Instruction::Call});
(void)Success;
assert(Success && !AnyDead && "Expected the check call to be successful!");
auto LoadStorePred = [&](Instruction &I) -> bool {
if (isa<LoadInst>(I))
getOrCreateAAFor<AAAlign>(
IRPosition::value(*cast<LoadInst>(I).getPointerOperand()));
else
getOrCreateAAFor<AAAlign>(
IRPosition::value(*cast<StoreInst>(I).getPointerOperand()));
return true;
};
Success = checkForAllInstructionsImpl(
OpcodeInstMap, LoadStorePred, nullptr, AnyDead,
{(unsigned)Instruction::Load, (unsigned)Instruction::Store});
(void)Success;
assert(Success && !AnyDead && "Expected the check call to be successful!");
}
/// Helpers to ease debugging through output streams and print calls.
///
///{
raw_ostream &llvm::operator<<(raw_ostream &OS, ChangeStatus S) {
return OS << (S == ChangeStatus::CHANGED ? "changed" : "unchanged");
}
raw_ostream &llvm::operator<<(raw_ostream &OS, IRPosition::Kind AP) {
switch (AP) {
case IRPosition::IRP_INVALID:
return OS << "inv";
case IRPosition::IRP_FLOAT:
return OS << "flt";
case IRPosition::IRP_RETURNED:
return OS << "fn_ret";
case IRPosition::IRP_CALL_SITE_RETURNED:
return OS << "cs_ret";
case IRPosition::IRP_FUNCTION:
return OS << "fn";
case IRPosition::IRP_CALL_SITE:
return OS << "cs";
case IRPosition::IRP_ARGUMENT:
return OS << "arg";
case IRPosition::IRP_CALL_SITE_ARGUMENT:
return OS << "cs_arg";
}
llvm_unreachable("Unknown attribute position!");
}
raw_ostream &llvm::operator<<(raw_ostream &OS, const IRPosition &Pos) {
const Value &AV = Pos.getAssociatedValue();
return OS << "{" << Pos.getPositionKind() << ":" << AV.getName() << " ["
<< Pos.getAnchorValue().getName() << "@" << Pos.getArgNo() << "]}";
}
template <typename base_ty, base_ty BestState, base_ty WorstState>
raw_ostream &llvm::
operator<<(raw_ostream &OS,
const IntegerStateBase<base_ty, BestState, WorstState> &S) {
return OS << "(" << S.getKnown() << "-" << S.getAssumed() << ")"
<< static_cast<const AbstractState &>(S);
}
raw_ostream &llvm::operator<<(raw_ostream &OS, const AbstractState &S) {
return OS << (!S.isValidState() ? "top" : (S.isAtFixpoint() ? "fix" : ""));
}
raw_ostream &llvm::operator<<(raw_ostream &OS, const AbstractAttribute &AA) {
AA.print(OS);
return OS;
}
void AbstractAttribute::print(raw_ostream &OS) const {
OS << "[P: " << getIRPosition() << "][" << getAsStr() << "][S: " << getState()
<< "]";
}
///}
/// ----------------------------------------------------------------------------
/// Pass (Manager) Boilerplate
/// ----------------------------------------------------------------------------
static bool runAttributorOnModule(Module &M, AnalysisGetter &AG) {
if (DisableAttributor)
return false;
LLVM_DEBUG(dbgs() << "[Attributor] Run on module with " << M.size()
<< " functions.\n");
// Create an Attributor and initially empty information cache that is filled
// while we identify default attribute opportunities.
InformationCache InfoCache(M, AG);
Attributor A(InfoCache, DepRecInterval);
for (Function &F : M)
A.initializeInformationCache(F);
for (Function &F : M) {
if (F.hasExactDefinition())
NumFnWithExactDefinition++;
else
NumFnWithoutExactDefinition++;
// We look at internal functions only on-demand but if any use is not a
// direct call, we have to do it eagerly.
if (F.hasLocalLinkage()) {
if (llvm::all_of(F.uses(), [](const Use &U) {
return ImmutableCallSite(U.getUser()) &&
ImmutableCallSite(U.getUser()).isCallee(&U);
}))
continue;
}
// Populate the Attributor with abstract attribute opportunities in the
// function and the information cache with IR information.
A.identifyDefaultAbstractAttributes(F);
}
return A.run(M) == ChangeStatus::CHANGED;
}
PreservedAnalyses AttributorPass::run(Module &M, ModuleAnalysisManager &AM) {
AnalysisGetter AG(AM);
if (runAttributorOnModule(M, AG)) {
// FIXME: Think about passes we will preserve and add them here.
return PreservedAnalyses::none();
}
return PreservedAnalyses::all();
}
namespace {
struct AttributorLegacyPass : public ModulePass {
static char ID;
AttributorLegacyPass() : ModulePass(ID) {
initializeAttributorLegacyPassPass(*PassRegistry::getPassRegistry());
}
bool runOnModule(Module &M) override {
if (skipModule(M))
return false;
AnalysisGetter AG;
return runAttributorOnModule(M, AG);
}
void getAnalysisUsage(AnalysisUsage &AU) const override {
// FIXME: Think about passes we will preserve and add them here.
AU.addRequired<TargetLibraryInfoWrapperPass>();
}
};
} // end anonymous namespace
Pass *llvm::createAttributorLegacyPass() { return new AttributorLegacyPass(); }
char AttributorLegacyPass::ID = 0;
const char AAReturnedValues::ID = 0;
const char AANoUnwind::ID = 0;
const char AANoSync::ID = 0;
const char AANoFree::ID = 0;
const char AANonNull::ID = 0;
const char AANoRecurse::ID = 0;
const char AAWillReturn::ID = 0;
const char AAUndefinedBehavior::ID = 0;
const char AANoAlias::ID = 0;
const char AAReachability::ID = 0;
const char AANoReturn::ID = 0;
const char AAIsDead::ID = 0;
const char AADereferenceable::ID = 0;
const char AAAlign::ID = 0;
const char AANoCapture::ID = 0;
const char AAValueSimplify::ID = 0;
const char AAHeapToStack::ID = 0;
const char AAMemoryBehavior::ID = 0;
// Macro magic to create the static generator function for attributes that
// follow the naming scheme.
#define SWITCH_PK_INV(CLASS, PK, POS_NAME) \
case IRPosition::PK: \
llvm_unreachable("Cannot create " #CLASS " for a " POS_NAME " position!");
#define SWITCH_PK_CREATE(CLASS, IRP, PK, SUFFIX) \
case IRPosition::PK: \
AA = new CLASS##SUFFIX(IRP); \
break;
#define CREATE_FUNCTION_ABSTRACT_ATTRIBUTE_FOR_POSITION(CLASS) \
CLASS &CLASS::createForPosition(const IRPosition &IRP, Attributor &A) { \
CLASS *AA = nullptr; \
switch (IRP.getPositionKind()) { \
SWITCH_PK_INV(CLASS, IRP_INVALID, "invalid") \
SWITCH_PK_INV(CLASS, IRP_FLOAT, "floating") \
SWITCH_PK_INV(CLASS, IRP_ARGUMENT, "argument") \
SWITCH_PK_INV(CLASS, IRP_RETURNED, "returned") \
SWITCH_PK_INV(CLASS, IRP_CALL_SITE_RETURNED, "call site returned") \
SWITCH_PK_INV(CLASS, IRP_CALL_SITE_ARGUMENT, "call site argument") \
SWITCH_PK_CREATE(CLASS, IRP, IRP_FUNCTION, Function) \
SWITCH_PK_CREATE(CLASS, IRP, IRP_CALL_SITE, CallSite) \
} \
return *AA; \
}
#define CREATE_VALUE_ABSTRACT_ATTRIBUTE_FOR_POSITION(CLASS) \
CLASS &CLASS::createForPosition(const IRPosition &IRP, Attributor &A) { \
CLASS *AA = nullptr; \
switch (IRP.getPositionKind()) { \
SWITCH_PK_INV(CLASS, IRP_INVALID, "invalid") \
SWITCH_PK_INV(CLASS, IRP_FUNCTION, "function") \
SWITCH_PK_INV(CLASS, IRP_CALL_SITE, "call site") \
SWITCH_PK_CREATE(CLASS, IRP, IRP_FLOAT, Floating) \
SWITCH_PK_CREATE(CLASS, IRP, IRP_ARGUMENT, Argument) \
SWITCH_PK_CREATE(CLASS, IRP, IRP_RETURNED, Returned) \
SWITCH_PK_CREATE(CLASS, IRP, IRP_CALL_SITE_RETURNED, CallSiteReturned) \
SWITCH_PK_CREATE(CLASS, IRP, IRP_CALL_SITE_ARGUMENT, CallSiteArgument) \
} \
return *AA; \
}
#define CREATE_ALL_ABSTRACT_ATTRIBUTE_FOR_POSITION(CLASS) \
CLASS &CLASS::createForPosition(const IRPosition &IRP, Attributor &A) { \
CLASS *AA = nullptr; \
switch (IRP.getPositionKind()) { \
SWITCH_PK_INV(CLASS, IRP_INVALID, "invalid") \
SWITCH_PK_CREATE(CLASS, IRP, IRP_FUNCTION, Function) \
SWITCH_PK_CREATE(CLASS, IRP, IRP_CALL_SITE, CallSite) \
SWITCH_PK_CREATE(CLASS, IRP, IRP_FLOAT, Floating) \
SWITCH_PK_CREATE(CLASS, IRP, IRP_ARGUMENT, Argument) \
SWITCH_PK_CREATE(CLASS, IRP, IRP_RETURNED, Returned) \
SWITCH_PK_CREATE(CLASS, IRP, IRP_CALL_SITE_RETURNED, CallSiteReturned) \
SWITCH_PK_CREATE(CLASS, IRP, IRP_CALL_SITE_ARGUMENT, CallSiteArgument) \
} \
return *AA; \
}
#define CREATE_FUNCTION_ONLY_ABSTRACT_ATTRIBUTE_FOR_POSITION(CLASS) \
CLASS &CLASS::createForPosition(const IRPosition &IRP, Attributor &A) { \
CLASS *AA = nullptr; \
switch (IRP.getPositionKind()) { \
SWITCH_PK_INV(CLASS, IRP_INVALID, "invalid") \
SWITCH_PK_INV(CLASS, IRP_ARGUMENT, "argument") \
SWITCH_PK_INV(CLASS, IRP_FLOAT, "floating") \
SWITCH_PK_INV(CLASS, IRP_RETURNED, "returned") \
SWITCH_PK_INV(CLASS, IRP_CALL_SITE_RETURNED, "call site returned") \
SWITCH_PK_INV(CLASS, IRP_CALL_SITE_ARGUMENT, "call site argument") \
SWITCH_PK_INV(CLASS, IRP_CALL_SITE, "call site") \
SWITCH_PK_CREATE(CLASS, IRP, IRP_FUNCTION, Function) \
} \
return *AA; \
}
#define CREATE_NON_RET_ABSTRACT_ATTRIBUTE_FOR_POSITION(CLASS) \
CLASS &CLASS::createForPosition(const IRPosition &IRP, Attributor &A) { \
CLASS *AA = nullptr; \
switch (IRP.getPositionKind()) { \
SWITCH_PK_INV(CLASS, IRP_INVALID, "invalid") \
SWITCH_PK_INV(CLASS, IRP_RETURNED, "returned") \
SWITCH_PK_CREATE(CLASS, IRP, IRP_FUNCTION, Function) \
SWITCH_PK_CREATE(CLASS, IRP, IRP_CALL_SITE, CallSite) \
SWITCH_PK_CREATE(CLASS, IRP, IRP_FLOAT, Floating) \
SWITCH_PK_CREATE(CLASS, IRP, IRP_ARGUMENT, Argument) \
SWITCH_PK_CREATE(CLASS, IRP, IRP_CALL_SITE_RETURNED, CallSiteReturned) \
SWITCH_PK_CREATE(CLASS, IRP, IRP_CALL_SITE_ARGUMENT, CallSiteArgument) \
} \
return *AA; \
}
CREATE_FUNCTION_ABSTRACT_ATTRIBUTE_FOR_POSITION(AANoUnwind)
CREATE_FUNCTION_ABSTRACT_ATTRIBUTE_FOR_POSITION(AANoSync)
CREATE_FUNCTION_ABSTRACT_ATTRIBUTE_FOR_POSITION(AANoRecurse)
CREATE_FUNCTION_ABSTRACT_ATTRIBUTE_FOR_POSITION(AAWillReturn)
CREATE_FUNCTION_ABSTRACT_ATTRIBUTE_FOR_POSITION(AANoReturn)
CREATE_FUNCTION_ABSTRACT_ATTRIBUTE_FOR_POSITION(AAReturnedValues)
CREATE_VALUE_ABSTRACT_ATTRIBUTE_FOR_POSITION(AANonNull)
CREATE_VALUE_ABSTRACT_ATTRIBUTE_FOR_POSITION(AANoAlias)
CREATE_VALUE_ABSTRACT_ATTRIBUTE_FOR_POSITION(AADereferenceable)
CREATE_VALUE_ABSTRACT_ATTRIBUTE_FOR_POSITION(AAAlign)
CREATE_VALUE_ABSTRACT_ATTRIBUTE_FOR_POSITION(AANoCapture)
CREATE_ALL_ABSTRACT_ATTRIBUTE_FOR_POSITION(AAValueSimplify)
CREATE_ALL_ABSTRACT_ATTRIBUTE_FOR_POSITION(AAIsDead)
CREATE_ALL_ABSTRACT_ATTRIBUTE_FOR_POSITION(AANoFree)
CREATE_FUNCTION_ONLY_ABSTRACT_ATTRIBUTE_FOR_POSITION(AAHeapToStack)
CREATE_FUNCTION_ONLY_ABSTRACT_ATTRIBUTE_FOR_POSITION(AAReachability)
CREATE_FUNCTION_ONLY_ABSTRACT_ATTRIBUTE_FOR_POSITION(AAUndefinedBehavior)
CREATE_NON_RET_ABSTRACT_ATTRIBUTE_FOR_POSITION(AAMemoryBehavior)
#undef CREATE_FUNCTION_ONLY_ABSTRACT_ATTRIBUTE_FOR_POSITION
#undef CREATE_FUNCTION_ABSTRACT_ATTRIBUTE_FOR_POSITION
#undef CREATE_NON_RET_ABSTRACT_ATTRIBUTE_FOR_POSITION
#undef CREATE_VALUE_ABSTRACT_ATTRIBUTE_FOR_POSITION
#undef CREATE_ALL_ABSTRACT_ATTRIBUTE_FOR_POSITION
#undef SWITCH_PK_CREATE
#undef SWITCH_PK_INV
INITIALIZE_PASS_BEGIN(AttributorLegacyPass, "attributor",
"Deduce and propagate attributes", false, false)
INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
INITIALIZE_PASS_END(AttributorLegacyPass, "attributor",
"Deduce and propagate attributes", false, false)
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