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07cc5a8df9edd94de7390607b0664cf83820089a
clang-p2996/llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
Matt Morehouse 7e042bb1d1 [libFuzzer] Port to Windows 
Summary:
Port libFuzzer to windows-msvc.
This patch allows libFuzzer targets to be built and run on Windows, using -fsanitize=fuzzer and/or fsanitize=fuzzer-no-link. It allows these forms of coverage instrumentation to work on Windows as well.
It does not fix all issues, such as those with -fsanitize-coverage=stack-depth, which is not usable on Windows as of this patch.
It also does not fix any libFuzzer integration tests. Nearly all of them fail to compile, fixing them will come in a later patch, so libFuzzer tests are disabled on Windows until them.

Patch By: metzman

Reviewers: morehouse, rnk

Reviewed By: morehouse, rnk

Subscribers: #sanitizers, delcypher, morehouse, kcc, eraman

Differential Revision: https://reviews.llvm.org/D51022

llvm-svn: 341082
2018-08-30 15:54:44 +00:00

876 lines
35 KiB
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//===-- SanitizerCoverage.cpp - coverage instrumentation for sanitizers ---===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Coverage instrumentation done on LLVM IR level, works with Sanitizers.
//
//===----------------------------------------------------------------------===//
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/Analysis/EHPersonalities.h"
#include "llvm/Analysis/PostDominators.h"
#include "llvm/IR/CFG.h"
#include "llvm/IR/CallSite.h"
#include "llvm/IR/Constant.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DebugInfo.h"
#include "llvm/IR/Dominators.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/GlobalVariable.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/InlineAsm.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/MDBuilder.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Type.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Transforms/Instrumentation.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/ModuleUtils.h"
using namespace llvm;
#define DEBUG_TYPE "sancov"
static const char *const SanCovTracePCIndirName =
"__sanitizer_cov_trace_pc_indir";
static const char *const SanCovTracePCName = "__sanitizer_cov_trace_pc";
static const char *const SanCovTraceCmp1 = "__sanitizer_cov_trace_cmp1";
static const char *const SanCovTraceCmp2 = "__sanitizer_cov_trace_cmp2";
static const char *const SanCovTraceCmp4 = "__sanitizer_cov_trace_cmp4";
static const char *const SanCovTraceCmp8 = "__sanitizer_cov_trace_cmp8";
static const char *const SanCovTraceConstCmp1 =
"__sanitizer_cov_trace_const_cmp1";
static const char *const SanCovTraceConstCmp2 =
"__sanitizer_cov_trace_const_cmp2";
static const char *const SanCovTraceConstCmp4 =
"__sanitizer_cov_trace_const_cmp4";
static const char *const SanCovTraceConstCmp8 =
"__sanitizer_cov_trace_const_cmp8";
static const char *const SanCovTraceDiv4 = "__sanitizer_cov_trace_div4";
static const char *const SanCovTraceDiv8 = "__sanitizer_cov_trace_div8";
static const char *const SanCovTraceGep = "__sanitizer_cov_trace_gep";
static const char *const SanCovTraceSwitchName = "__sanitizer_cov_trace_switch";
static const char *const SanCovModuleCtorName = "sancov.module_ctor";
static const uint64_t SanCtorAndDtorPriority = 2;
static const char *const SanCovTracePCGuardName =
"__sanitizer_cov_trace_pc_guard";
static const char *const SanCovTracePCGuardInitName =
"__sanitizer_cov_trace_pc_guard_init";
static const char *const SanCov8bitCountersInitName =
"__sanitizer_cov_8bit_counters_init";
static const char *const SanCovPCsInitName = "__sanitizer_cov_pcs_init";
static const char *const SanCovGuardsSectionName = "sancov_guards";
static const char *const SanCovCountersSectionName = "sancov_cntrs";
static const char *const SanCovPCsSectionName = "sancov_pcs";
static const char *const SanCovLowestStackName = "__sancov_lowest_stack";
static cl::opt<int> ClCoverageLevel(
"sanitizer-coverage-level",
cl::desc("Sanitizer Coverage. 0: none, 1: entry block, 2: all blocks, "
"3: all blocks and critical edges"),
cl::Hidden, cl::init(0));
static cl::opt<bool> ClTracePC("sanitizer-coverage-trace-pc",
cl::desc("Experimental pc tracing"), cl::Hidden,
cl::init(false));
static cl::opt<bool> ClTracePCGuard("sanitizer-coverage-trace-pc-guard",
cl::desc("pc tracing with a guard"),
cl::Hidden, cl::init(false));
// If true, we create a global variable that contains PCs of all instrumented
// BBs, put this global into a named section, and pass this section's bounds
// to __sanitizer_cov_pcs_init.
// This way the coverage instrumentation does not need to acquire the PCs
// at run-time. Works with trace-pc-guard and inline-8bit-counters.
static cl::opt<bool> ClCreatePCTable("sanitizer-coverage-pc-table",
cl::desc("create a static PC table"),
cl::Hidden, cl::init(false));
static cl::opt<bool>
ClInline8bitCounters("sanitizer-coverage-inline-8bit-counters",
cl::desc("increments 8-bit counter for every edge"),
cl::Hidden, cl::init(false));
static cl::opt<bool>
ClCMPTracing("sanitizer-coverage-trace-compares",
cl::desc("Tracing of CMP and similar instructions"),
cl::Hidden, cl::init(false));
static cl::opt<bool> ClDIVTracing("sanitizer-coverage-trace-divs",
cl::desc("Tracing of DIV instructions"),
cl::Hidden, cl::init(false));
static cl::opt<bool> ClGEPTracing("sanitizer-coverage-trace-geps",
cl::desc("Tracing of GEP instructions"),
cl::Hidden, cl::init(false));
static cl::opt<bool>
ClPruneBlocks("sanitizer-coverage-prune-blocks",
cl::desc("Reduce the number of instrumented blocks"),
cl::Hidden, cl::init(true));
static cl::opt<bool> ClStackDepth("sanitizer-coverage-stack-depth",
cl::desc("max stack depth tracing"),
cl::Hidden, cl::init(false));
namespace {
SanitizerCoverageOptions getOptions(int LegacyCoverageLevel) {
SanitizerCoverageOptions Res;
switch (LegacyCoverageLevel) {
case 0:
Res.CoverageType = SanitizerCoverageOptions::SCK_None;
break;
case 1:
Res.CoverageType = SanitizerCoverageOptions::SCK_Function;
break;
case 2:
Res.CoverageType = SanitizerCoverageOptions::SCK_BB;
break;
case 3:
Res.CoverageType = SanitizerCoverageOptions::SCK_Edge;
break;
case 4:
Res.CoverageType = SanitizerCoverageOptions::SCK_Edge;
Res.IndirectCalls = true;
break;
}
return Res;
}
SanitizerCoverageOptions OverrideFromCL(SanitizerCoverageOptions Options) {
// Sets CoverageType and IndirectCalls.
SanitizerCoverageOptions CLOpts = getOptions(ClCoverageLevel);
Options.CoverageType = std::max(Options.CoverageType, CLOpts.CoverageType);
Options.IndirectCalls |= CLOpts.IndirectCalls;
Options.TraceCmp |= ClCMPTracing;
Options.TraceDiv |= ClDIVTracing;
Options.TraceGep |= ClGEPTracing;
Options.TracePC |= ClTracePC;
Options.TracePCGuard |= ClTracePCGuard;
Options.Inline8bitCounters |= ClInline8bitCounters;
Options.PCTable |= ClCreatePCTable;
Options.NoPrune |= !ClPruneBlocks;
Options.StackDepth |= ClStackDepth;
if (!Options.TracePCGuard && !Options.TracePC &&
!Options.Inline8bitCounters && !Options.StackDepth)
Options.TracePCGuard = true; // TracePCGuard is default.
return Options;
}
class SanitizerCoverageModule : public ModulePass {
public:
SanitizerCoverageModule(
const SanitizerCoverageOptions &Options = SanitizerCoverageOptions())
: ModulePass(ID), Options(OverrideFromCL(Options)) {
initializeSanitizerCoverageModulePass(*PassRegistry::getPassRegistry());
}
bool runOnModule(Module &M) override;
bool runOnFunction(Function &F);
static char ID; // Pass identification, replacement for typeid
StringRef getPassName() const override { return "SanitizerCoverageModule"; }
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.addRequired<DominatorTreeWrapperPass>();
AU.addRequired<PostDominatorTreeWrapperPass>();
}
private:
void InjectCoverageForIndirectCalls(Function &F,
ArrayRef<Instruction *> IndirCalls);
void InjectTraceForCmp(Function &F, ArrayRef<Instruction *> CmpTraceTargets);
void InjectTraceForDiv(Function &F,
ArrayRef<BinaryOperator *> DivTraceTargets);
void InjectTraceForGep(Function &F,
ArrayRef<GetElementPtrInst *> GepTraceTargets);
void InjectTraceForSwitch(Function &F,
ArrayRef<Instruction *> SwitchTraceTargets);
bool InjectCoverage(Function &F, ArrayRef<BasicBlock *> AllBlocks,
bool IsLeafFunc = true);
GlobalVariable *CreateFunctionLocalArrayInSection(size_t NumElements,
Function &F, Type *Ty,
const char *Section);
GlobalVariable *CreatePCArray(Function &F, ArrayRef<BasicBlock *> AllBlocks);
void CreateFunctionLocalArrays(Function &F, ArrayRef<BasicBlock *> AllBlocks);
void InjectCoverageAtBlock(Function &F, BasicBlock &BB, size_t Idx,
bool IsLeafFunc = true);
Function *CreateInitCallsForSections(Module &M, const char *InitFunctionName,
Type *Ty, const char *Section);
std::pair<GlobalVariable *, GlobalVariable *>
CreateSecStartEnd(Module &M, const char *Section, Type *Ty);
void SetNoSanitizeMetadata(Instruction *I) {
I->setMetadata(I->getModule()->getMDKindID("nosanitize"),
MDNode::get(*C, None));
}
std::string getSectionName(const std::string &Section) const;
std::string getSectionStart(const std::string &Section) const;
std::string getSectionEnd(const std::string &Section) const;
Function *SanCovTracePCIndir;
Function *SanCovTracePC, *SanCovTracePCGuard;
Function *SanCovTraceCmpFunction[4];
Function *SanCovTraceConstCmpFunction[4];
Function *SanCovTraceDivFunction[2];
Function *SanCovTraceGepFunction;
Function *SanCovTraceSwitchFunction;
GlobalVariable *SanCovLowestStack;
InlineAsm *EmptyAsm;
Type *IntptrTy, *IntptrPtrTy, *Int64Ty, *Int64PtrTy, *Int32Ty, *Int32PtrTy,
*Int16Ty, *Int8Ty, *Int8PtrTy;
Module *CurModule;
Triple TargetTriple;
LLVMContext *C;
const DataLayout *DL;
GlobalVariable *FunctionGuardArray; // for trace-pc-guard.
GlobalVariable *Function8bitCounterArray; // for inline-8bit-counters.
GlobalVariable *FunctionPCsArray; // for pc-table.
SmallVector<GlobalValue *, 20> GlobalsToAppendToUsed;
SmallVector<GlobalValue *, 20> GlobalsToAppendToCompilerUsed;
SanitizerCoverageOptions Options;
};
} // namespace
std::pair<GlobalVariable *, GlobalVariable *>
SanitizerCoverageModule::CreateSecStartEnd(Module &M, const char *Section,
Type *Ty) {
GlobalVariable *SecStart =
new GlobalVariable(M, Ty, false, GlobalVariable::ExternalLinkage, nullptr,
getSectionStart(Section));
SecStart->setVisibility(GlobalValue::HiddenVisibility);
GlobalVariable *SecEnd =
new GlobalVariable(M, Ty, false, GlobalVariable::ExternalLinkage,
nullptr, getSectionEnd(Section));
SecEnd->setVisibility(GlobalValue::HiddenVisibility);
return std::make_pair(SecStart, SecEnd);
}
Function *SanitizerCoverageModule::CreateInitCallsForSections(
Module &M, const char *InitFunctionName, Type *Ty,
const char *Section) {
IRBuilder<> IRB(M.getContext());
auto SecStartEnd = CreateSecStartEnd(M, Section, Ty);
auto SecStart = SecStartEnd.first;
auto SecEnd = SecStartEnd.second;
Function *CtorFunc;
Value *SecStartPtr = nullptr;
// Account for the fact that on windows-msvc __start_* symbols actually
// point to a uint64_t before the start of the array.
if (TargetTriple.getObjectFormat() == Triple::COFF) {
auto SecStartI8Ptr = IRB.CreatePointerCast(SecStart, Int8PtrTy);
auto GEP = IRB.CreateGEP(SecStartI8Ptr,
ConstantInt::get(IntptrTy, sizeof(uint64_t)));
SecStartPtr = IRB.CreatePointerCast(GEP, Ty);
} else {
SecStartPtr = IRB.CreatePointerCast(SecStart, Ty);
}
std::tie(CtorFunc, std::ignore) = createSanitizerCtorAndInitFunctions(
M, SanCovModuleCtorName, InitFunctionName, {Ty, Ty},
{SecStartPtr, IRB.CreatePointerCast(SecEnd, Ty)});
if (TargetTriple.supportsCOMDAT()) {
// Use comdat to dedup CtorFunc.
CtorFunc->setComdat(M.getOrInsertComdat(SanCovModuleCtorName));
appendToGlobalCtors(M, CtorFunc, SanCtorAndDtorPriority, CtorFunc);
} else {
appendToGlobalCtors(M, CtorFunc, SanCtorAndDtorPriority);
}
return CtorFunc;
}
bool SanitizerCoverageModule::runOnModule(Module &M) {
if (Options.CoverageType == SanitizerCoverageOptions::SCK_None)
return false;
C = &(M.getContext());
DL = &M.getDataLayout();
CurModule = &M;
TargetTriple = Triple(M.getTargetTriple());
FunctionGuardArray = nullptr;
Function8bitCounterArray = nullptr;
FunctionPCsArray = nullptr;
IntptrTy = Type::getIntNTy(*C, DL->getPointerSizeInBits());
IntptrPtrTy = PointerType::getUnqual(IntptrTy);
Type *VoidTy = Type::getVoidTy(*C);
IRBuilder<> IRB(*C);
Int64PtrTy = PointerType::getUnqual(IRB.getInt64Ty());
Int32PtrTy = PointerType::getUnqual(IRB.getInt32Ty());
Int8PtrTy = PointerType::getUnqual(IRB.getInt8Ty());
Int64Ty = IRB.getInt64Ty();
Int32Ty = IRB.getInt32Ty();
Int16Ty = IRB.getInt16Ty();
Int8Ty = IRB.getInt8Ty();
SanCovTracePCIndir = checkSanitizerInterfaceFunction(
M.getOrInsertFunction(SanCovTracePCIndirName, VoidTy, IntptrTy));
SanCovTraceCmpFunction[0] =
checkSanitizerInterfaceFunction(M.getOrInsertFunction(
SanCovTraceCmp1, VoidTy, IRB.getInt8Ty(), IRB.getInt8Ty()));
SanCovTraceCmpFunction[1] = checkSanitizerInterfaceFunction(
M.getOrInsertFunction(SanCovTraceCmp2, VoidTy, IRB.getInt16Ty(),
IRB.getInt16Ty()));
SanCovTraceCmpFunction[2] = checkSanitizerInterfaceFunction(
M.getOrInsertFunction(SanCovTraceCmp4, VoidTy, IRB.getInt32Ty(),
IRB.getInt32Ty()));
SanCovTraceCmpFunction[3] =
checkSanitizerInterfaceFunction(M.getOrInsertFunction(
SanCovTraceCmp8, VoidTy, Int64Ty, Int64Ty));
SanCovTraceConstCmpFunction[0] =
checkSanitizerInterfaceFunction(M.getOrInsertFunction(
SanCovTraceConstCmp1, VoidTy, Int8Ty, Int8Ty));
SanCovTraceConstCmpFunction[1] =
checkSanitizerInterfaceFunction(M.getOrInsertFunction(
SanCovTraceConstCmp2, VoidTy, Int16Ty, Int16Ty));
SanCovTraceConstCmpFunction[2] =
checkSanitizerInterfaceFunction(M.getOrInsertFunction(
SanCovTraceConstCmp4, VoidTy, Int32Ty, Int32Ty));
SanCovTraceConstCmpFunction[3] =
checkSanitizerInterfaceFunction(M.getOrInsertFunction(
SanCovTraceConstCmp8, VoidTy, Int64Ty, Int64Ty));
SanCovTraceDivFunction[0] =
checkSanitizerInterfaceFunction(M.getOrInsertFunction(
SanCovTraceDiv4, VoidTy, IRB.getInt32Ty()));
SanCovTraceDivFunction[1] =
checkSanitizerInterfaceFunction(M.getOrInsertFunction(
SanCovTraceDiv8, VoidTy, Int64Ty));
SanCovTraceGepFunction =
checkSanitizerInterfaceFunction(M.getOrInsertFunction(
SanCovTraceGep, VoidTy, IntptrTy));
SanCovTraceSwitchFunction =
checkSanitizerInterfaceFunction(M.getOrInsertFunction(
SanCovTraceSwitchName, VoidTy, Int64Ty, Int64PtrTy));
Constant *SanCovLowestStackConstant =
M.getOrInsertGlobal(SanCovLowestStackName, IntptrTy);
SanCovLowestStack = cast<GlobalVariable>(SanCovLowestStackConstant);
SanCovLowestStack->setThreadLocalMode(
GlobalValue::ThreadLocalMode::InitialExecTLSModel);
if (Options.StackDepth && !SanCovLowestStack->isDeclaration())
SanCovLowestStack->setInitializer(Constant::getAllOnesValue(IntptrTy));
// Make sure smaller parameters are zero-extended to i64 as required by the
// x86_64 ABI.
if (TargetTriple.getArch() == Triple::x86_64) {
for (int i = 0; i < 3; i++) {
SanCovTraceCmpFunction[i]->addParamAttr(0, Attribute::ZExt);
SanCovTraceCmpFunction[i]->addParamAttr(1, Attribute::ZExt);
SanCovTraceConstCmpFunction[i]->addParamAttr(0, Attribute::ZExt);
SanCovTraceConstCmpFunction[i]->addParamAttr(1, Attribute::ZExt);
}
SanCovTraceDivFunction[0]->addParamAttr(0, Attribute::ZExt);
}
// We insert an empty inline asm after cov callbacks to avoid callback merge.
EmptyAsm = InlineAsm::get(FunctionType::get(IRB.getVoidTy(), false),
StringRef(""), StringRef(""),
/*hasSideEffects=*/true);
SanCovTracePC = checkSanitizerInterfaceFunction(
M.getOrInsertFunction(SanCovTracePCName, VoidTy));
SanCovTracePCGuard = checkSanitizerInterfaceFunction(M.getOrInsertFunction(
SanCovTracePCGuardName, VoidTy, Int32PtrTy));
for (auto &F : M)
runOnFunction(F);
Function *Ctor = nullptr;
if (FunctionGuardArray)
Ctor = CreateInitCallsForSections(M, SanCovTracePCGuardInitName, Int32PtrTy,
SanCovGuardsSectionName);
if (Function8bitCounterArray)
Ctor = CreateInitCallsForSections(M, SanCov8bitCountersInitName, Int8PtrTy,
SanCovCountersSectionName);
if (Ctor && Options.PCTable) {
auto SecStartEnd = CreateSecStartEnd(M, SanCovPCsSectionName, IntptrPtrTy);
Function *InitFunction = declareSanitizerInitFunction(
M, SanCovPCsInitName, {IntptrPtrTy, IntptrPtrTy});
IRBuilder<> IRBCtor(Ctor->getEntryBlock().getTerminator());
Value *SecStartPtr = nullptr;
// Account for the fact that on windows-msvc __start_pc_table actually
// points to a uint64_t before the start of the PC table.
if (TargetTriple.getObjectFormat() == Triple::COFF) {
auto SecStartI8Ptr = IRB.CreatePointerCast(SecStartEnd.first, Int8PtrTy);
auto GEP = IRB.CreateGEP(SecStartI8Ptr,
ConstantInt::get(IntptrTy, sizeof(uint64_t)));
SecStartPtr = IRB.CreatePointerCast(GEP, IntptrPtrTy);
} else {
SecStartPtr = IRB.CreatePointerCast(SecStartEnd.first, IntptrPtrTy);
}
IRBCtor.CreateCall(
InitFunction,
{SecStartPtr, IRB.CreatePointerCast(SecStartEnd.second, IntptrPtrTy)});
}
// We don't reference these arrays directly in any of our runtime functions,
// so we need to prevent them from being dead stripped.
if (TargetTriple.isOSBinFormatMachO())
appendToUsed(M, GlobalsToAppendToUsed);
appendToCompilerUsed(M, GlobalsToAppendToCompilerUsed);
return true;
}
// True if block has successors and it dominates all of them.
static bool isFullDominator(const BasicBlock *BB, const DominatorTree *DT) {
if (succ_begin(BB) == succ_end(BB))
return false;
for (const BasicBlock *SUCC : make_range(succ_begin(BB), succ_end(BB))) {
if (!DT->dominates(BB, SUCC))
return false;
}
return true;
}
// True if block has predecessors and it postdominates all of them.
static bool isFullPostDominator(const BasicBlock *BB,
const PostDominatorTree *PDT) {
if (pred_begin(BB) == pred_end(BB))
return false;
for (const BasicBlock *PRED : make_range(pred_begin(BB), pred_end(BB))) {
if (!PDT->dominates(BB, PRED))
return false;
}
return true;
}
static bool shouldInstrumentBlock(const Function &F, const BasicBlock *BB,
const DominatorTree *DT,
const PostDominatorTree *PDT,
const SanitizerCoverageOptions &Options) {
// Don't insert coverage for unreachable blocks: we will never call
// __sanitizer_cov() for them, so counting them in
// NumberOfInstrumentedBlocks() might complicate calculation of code coverage
// percentage. Also, unreachable instructions frequently have no debug
// locations.
if (isa<UnreachableInst>(BB->getTerminator()))
return false;
// Don't insert coverage into blocks without a valid insertion point
// (catchswitch blocks).
if (BB->getFirstInsertionPt() == BB->end())
return false;
if (Options.NoPrune || &F.getEntryBlock() == BB)
return true;
if (Options.CoverageType == SanitizerCoverageOptions::SCK_Function &&
&F.getEntryBlock() != BB)
return false;
// Do not instrument full dominators, or full post-dominators with multiple
// predecessors.
return !isFullDominator(BB, DT)
&& !(isFullPostDominator(BB, PDT) && !BB->getSinglePredecessor());
}
bool SanitizerCoverageModule::runOnFunction(Function &F) {
if (F.empty())
return false;
if (F.getName().find(".module_ctor") != std::string::npos)
return false; // Should not instrument sanitizer init functions.
if (F.getName().startswith("__sanitizer_"))
return false; // Don't instrument __sanitizer_* callbacks.
// Don't touch available_externally functions, their actual body is elewhere.
if (F.getLinkage() == GlobalValue::AvailableExternallyLinkage)
return false;
// Don't instrument MSVC CRT configuration helpers. They may run before normal
// initialization.
if (F.getName() == "__local_stdio_printf_options" ||
F.getName() == "__local_stdio_scanf_options")
return false;
if (isa<UnreachableInst>(F.getEntryBlock().getTerminator()))
return false;
// Don't instrument functions using SEH for now. Splitting basic blocks like
// we do for coverage breaks WinEHPrepare.
// FIXME: Remove this when SEH no longer uses landingpad pattern matching.
if (F.hasPersonalityFn() &&
isAsynchronousEHPersonality(classifyEHPersonality(F.getPersonalityFn())))
return false;
if (Options.CoverageType >= SanitizerCoverageOptions::SCK_Edge)
SplitAllCriticalEdges(F);
SmallVector<Instruction *, 8> IndirCalls;
SmallVector<BasicBlock *, 16> BlocksToInstrument;
SmallVector<Instruction *, 8> CmpTraceTargets;
SmallVector<Instruction *, 8> SwitchTraceTargets;
SmallVector<BinaryOperator *, 8> DivTraceTargets;
SmallVector<GetElementPtrInst *, 8> GepTraceTargets;
const DominatorTree *DT =
&getAnalysis<DominatorTreeWrapperPass>(F).getDomTree();
const PostDominatorTree *PDT =
&getAnalysis<PostDominatorTreeWrapperPass>(F).getPostDomTree();
bool IsLeafFunc = true;
for (auto &BB : F) {
if (shouldInstrumentBlock(F, &BB, DT, PDT, Options))
BlocksToInstrument.push_back(&BB);
for (auto &Inst : BB) {
if (Options.IndirectCalls) {
CallSite CS(&Inst);
if (CS && !CS.getCalledFunction())
IndirCalls.push_back(&Inst);
}
if (Options.TraceCmp) {
if (isa<ICmpInst>(&Inst))
CmpTraceTargets.push_back(&Inst);
if (isa<SwitchInst>(&Inst))
SwitchTraceTargets.push_back(&Inst);
}
if (Options.TraceDiv)
if (BinaryOperator *BO = dyn_cast<BinaryOperator>(&Inst))
if (BO->getOpcode() == Instruction::SDiv ||
BO->getOpcode() == Instruction::UDiv)
DivTraceTargets.push_back(BO);
if (Options.TraceGep)
if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(&Inst))
GepTraceTargets.push_back(GEP);
if (Options.StackDepth)
if (isa<InvokeInst>(Inst) ||
(isa<CallInst>(Inst) && !isa<IntrinsicInst>(Inst)))
IsLeafFunc = false;
}
}
InjectCoverage(F, BlocksToInstrument, IsLeafFunc);
InjectCoverageForIndirectCalls(F, IndirCalls);
InjectTraceForCmp(F, CmpTraceTargets);
InjectTraceForSwitch(F, SwitchTraceTargets);
InjectTraceForDiv(F, DivTraceTargets);
InjectTraceForGep(F, GepTraceTargets);
return true;
}
GlobalVariable *SanitizerCoverageModule::CreateFunctionLocalArrayInSection(
size_t NumElements, Function &F, Type *Ty, const char *Section) {
ArrayType *ArrayTy = ArrayType::get(Ty, NumElements);
auto Array = new GlobalVariable(
*CurModule, ArrayTy, false, GlobalVariable::PrivateLinkage,
Constant::getNullValue(ArrayTy), "__sancov_gen_");
if (auto Comdat = F.getComdat())
Array->setComdat(Comdat);
Array->setSection(getSectionName(Section));
Array->setAlignment(Ty->isPointerTy() ? DL->getPointerSize()
: Ty->getPrimitiveSizeInBits() / 8);
return Array;
}
GlobalVariable *
SanitizerCoverageModule::CreatePCArray(Function &F,
ArrayRef<BasicBlock *> AllBlocks) {
size_t N = AllBlocks.size();
assert(N);
SmallVector<Constant *, 32> PCs;
IRBuilder<> IRB(&*F.getEntryBlock().getFirstInsertionPt());
for (size_t i = 0; i < N; i++) {
if (&F.getEntryBlock() == AllBlocks[i]) {
PCs.push_back((Constant *)IRB.CreatePointerCast(&F, IntptrPtrTy));
PCs.push_back((Constant *)IRB.CreateIntToPtr(
ConstantInt::get(IntptrTy, 1), IntptrPtrTy));
} else {
PCs.push_back((Constant *)IRB.CreatePointerCast(
BlockAddress::get(AllBlocks[i]), IntptrPtrTy));
PCs.push_back((Constant *)IRB.CreateIntToPtr(
ConstantInt::get(IntptrTy, 0), IntptrPtrTy));
}
}
auto *PCArray = CreateFunctionLocalArrayInSection(N * 2, F, IntptrPtrTy,
SanCovPCsSectionName);
PCArray->setInitializer(
ConstantArray::get(ArrayType::get(IntptrPtrTy, N * 2), PCs));
PCArray->setConstant(true);
return PCArray;
}
void SanitizerCoverageModule::CreateFunctionLocalArrays(
Function &F, ArrayRef<BasicBlock *> AllBlocks) {
if (Options.TracePCGuard) {
FunctionGuardArray = CreateFunctionLocalArrayInSection(
AllBlocks.size(), F, Int32Ty, SanCovGuardsSectionName);
GlobalsToAppendToUsed.push_back(FunctionGuardArray);
GlobalsToAppendToCompilerUsed.push_back(FunctionGuardArray);
MDNode *MD = MDNode::get(F.getContext(), ValueAsMetadata::get(&F));
FunctionGuardArray->addMetadata(LLVMContext::MD_associated, *MD);
}
if (Options.Inline8bitCounters) {
Function8bitCounterArray = CreateFunctionLocalArrayInSection(
AllBlocks.size(), F, Int8Ty, SanCovCountersSectionName);
GlobalsToAppendToCompilerUsed.push_back(Function8bitCounterArray);
MDNode *MD = MDNode::get(F.getContext(), ValueAsMetadata::get(&F));
Function8bitCounterArray->addMetadata(LLVMContext::MD_associated, *MD);
}
if (Options.PCTable) {
FunctionPCsArray = CreatePCArray(F, AllBlocks);
GlobalsToAppendToCompilerUsed.push_back(FunctionPCsArray);
MDNode *MD = MDNode::get(F.getContext(), ValueAsMetadata::get(&F));
FunctionPCsArray->addMetadata(LLVMContext::MD_associated, *MD);
}
}
bool SanitizerCoverageModule::InjectCoverage(Function &F,
ArrayRef<BasicBlock *> AllBlocks,
bool IsLeafFunc) {
if (AllBlocks.empty()) return false;
CreateFunctionLocalArrays(F, AllBlocks);
for (size_t i = 0, N = AllBlocks.size(); i < N; i++)
InjectCoverageAtBlock(F, *AllBlocks[i], i, IsLeafFunc);
return true;
}
// On every indirect call we call a run-time function
// __sanitizer_cov_indir_call* with two parameters:
// - callee address,
// - global cache array that contains CacheSize pointers (zero-initialized).
// The cache is used to speed up recording the caller-callee pairs.
// The address of the caller is passed implicitly via caller PC.
// CacheSize is encoded in the name of the run-time function.
void SanitizerCoverageModule::InjectCoverageForIndirectCalls(
Function &F, ArrayRef<Instruction *> IndirCalls) {
if (IndirCalls.empty())
return;
assert(Options.TracePC || Options.TracePCGuard || Options.Inline8bitCounters);
for (auto I : IndirCalls) {
IRBuilder<> IRB(I);
CallSite CS(I);
Value *Callee = CS.getCalledValue();
if (isa<InlineAsm>(Callee))
continue;
IRB.CreateCall(SanCovTracePCIndir, IRB.CreatePointerCast(Callee, IntptrTy));
}
}
// For every switch statement we insert a call:
// __sanitizer_cov_trace_switch(CondValue,
// {NumCases, ValueSizeInBits, Case0Value, Case1Value, Case2Value, ... })
void SanitizerCoverageModule::InjectTraceForSwitch(
Function &, ArrayRef<Instruction *> SwitchTraceTargets) {
for (auto I : SwitchTraceTargets) {
if (SwitchInst *SI = dyn_cast<SwitchInst>(I)) {
IRBuilder<> IRB(I);
SmallVector<Constant *, 16> Initializers;
Value *Cond = SI->getCondition();
if (Cond->getType()->getScalarSizeInBits() >
Int64Ty->getScalarSizeInBits())
continue;
Initializers.push_back(ConstantInt::get(Int64Ty, SI->getNumCases()));
Initializers.push_back(
ConstantInt::get(Int64Ty, Cond->getType()->getScalarSizeInBits()));
if (Cond->getType()->getScalarSizeInBits() <
Int64Ty->getScalarSizeInBits())
Cond = IRB.CreateIntCast(Cond, Int64Ty, false);
for (auto It : SI->cases()) {
Constant *C = It.getCaseValue();
if (C->getType()->getScalarSizeInBits() <
Int64Ty->getScalarSizeInBits())
C = ConstantExpr::getCast(CastInst::ZExt, It.getCaseValue(), Int64Ty);
Initializers.push_back(C);
}
llvm::sort(Initializers.begin() + 2, Initializers.end(),
[](const Constant *A, const Constant *B) {
return cast<ConstantInt>(A)->getLimitedValue() <
cast<ConstantInt>(B)->getLimitedValue();
});
ArrayType *ArrayOfInt64Ty = ArrayType::get(Int64Ty, Initializers.size());
GlobalVariable *GV = new GlobalVariable(
*CurModule, ArrayOfInt64Ty, false, GlobalVariable::InternalLinkage,
ConstantArray::get(ArrayOfInt64Ty, Initializers),
"__sancov_gen_cov_switch_values");
IRB.CreateCall(SanCovTraceSwitchFunction,
{Cond, IRB.CreatePointerCast(GV, Int64PtrTy)});
}
}
}
void SanitizerCoverageModule::InjectTraceForDiv(
Function &, ArrayRef<BinaryOperator *> DivTraceTargets) {
for (auto BO : DivTraceTargets) {
IRBuilder<> IRB(BO);
Value *A1 = BO->getOperand(1);
if (isa<ConstantInt>(A1)) continue;
if (!A1->getType()->isIntegerTy())
continue;
uint64_t TypeSize = DL->getTypeStoreSizeInBits(A1->getType());
int CallbackIdx = TypeSize == 32 ? 0 :
TypeSize == 64 ? 1 : -1;
if (CallbackIdx < 0) continue;
auto Ty = Type::getIntNTy(*C, TypeSize);
IRB.CreateCall(SanCovTraceDivFunction[CallbackIdx],
{IRB.CreateIntCast(A1, Ty, true)});
}
}
void SanitizerCoverageModule::InjectTraceForGep(
Function &, ArrayRef<GetElementPtrInst *> GepTraceTargets) {
for (auto GEP : GepTraceTargets) {
IRBuilder<> IRB(GEP);
for (auto I = GEP->idx_begin(); I != GEP->idx_end(); ++I)
if (!isa<ConstantInt>(*I) && (*I)->getType()->isIntegerTy())
IRB.CreateCall(SanCovTraceGepFunction,
{IRB.CreateIntCast(*I, IntptrTy, true)});
}
}
void SanitizerCoverageModule::InjectTraceForCmp(
Function &, ArrayRef<Instruction *> CmpTraceTargets) {
for (auto I : CmpTraceTargets) {
if (ICmpInst *ICMP = dyn_cast<ICmpInst>(I)) {
IRBuilder<> IRB(ICMP);
Value *A0 = ICMP->getOperand(0);
Value *A1 = ICMP->getOperand(1);
if (!A0->getType()->isIntegerTy())
continue;
uint64_t TypeSize = DL->getTypeStoreSizeInBits(A0->getType());
int CallbackIdx = TypeSize == 8 ? 0 :
TypeSize == 16 ? 1 :
TypeSize == 32 ? 2 :
TypeSize == 64 ? 3 : -1;
if (CallbackIdx < 0) continue;
// __sanitizer_cov_trace_cmp((type_size << 32) | predicate, A0, A1);
auto CallbackFunc = SanCovTraceCmpFunction[CallbackIdx];
bool FirstIsConst = isa<ConstantInt>(A0);
bool SecondIsConst = isa<ConstantInt>(A1);
// If both are const, then we don't need such a comparison.
if (FirstIsConst && SecondIsConst) continue;
// If only one is const, then make it the first callback argument.
if (FirstIsConst || SecondIsConst) {
CallbackFunc = SanCovTraceConstCmpFunction[CallbackIdx];
if (SecondIsConst)
std::swap(A0, A1);
}
auto Ty = Type::getIntNTy(*C, TypeSize);
IRB.CreateCall(CallbackFunc, {IRB.CreateIntCast(A0, Ty, true),
IRB.CreateIntCast(A1, Ty, true)});
}
}
}
void SanitizerCoverageModule::InjectCoverageAtBlock(Function &F, BasicBlock &BB,
size_t Idx,
bool IsLeafFunc) {
BasicBlock::iterator IP = BB.getFirstInsertionPt();
bool IsEntryBB = &BB == &F.getEntryBlock();
DebugLoc EntryLoc;
if (IsEntryBB) {
if (auto SP = F.getSubprogram())
EntryLoc = DebugLoc::get(SP->getScopeLine(), 0, SP);
// Keep static allocas and llvm.localescape calls in the entry block. Even
// if we aren't splitting the block, it's nice for allocas to be before
// calls.
IP = PrepareToSplitEntryBlock(BB, IP);
} else {
EntryLoc = IP->getDebugLoc();
}
IRBuilder<> IRB(&*IP);
IRB.SetCurrentDebugLocation(EntryLoc);
if (Options.TracePC) {
IRB.CreateCall(SanCovTracePC); // gets the PC using GET_CALLER_PC.
IRB.CreateCall(EmptyAsm, {}); // Avoids callback merge.
}
if (Options.TracePCGuard) {
auto GuardPtr = IRB.CreateIntToPtr(
IRB.CreateAdd(IRB.CreatePointerCast(FunctionGuardArray, IntptrTy),
ConstantInt::get(IntptrTy, Idx * 4)),
Int32PtrTy);
IRB.CreateCall(SanCovTracePCGuard, GuardPtr);
IRB.CreateCall(EmptyAsm, {}); // Avoids callback merge.
}
if (Options.Inline8bitCounters) {
auto CounterPtr = IRB.CreateGEP(
Function8bitCounterArray,
{ConstantInt::get(IntptrTy, 0), ConstantInt::get(IntptrTy, Idx)});
auto Load = IRB.CreateLoad(CounterPtr);
auto Inc = IRB.CreateAdd(Load, ConstantInt::get(Int8Ty, 1));
auto Store = IRB.CreateStore(Inc, CounterPtr);
SetNoSanitizeMetadata(Load);
SetNoSanitizeMetadata(Store);
}
if (Options.StackDepth && IsEntryBB && !IsLeafFunc) {
// Check stack depth. If it's the deepest so far, record it.
Function *GetFrameAddr =
Intrinsic::getDeclaration(F.getParent(), Intrinsic::frameaddress);
auto FrameAddrPtr =
IRB.CreateCall(GetFrameAddr, {Constant::getNullValue(Int32Ty)});
auto FrameAddrInt = IRB.CreatePtrToInt(FrameAddrPtr, IntptrTy);
auto LowestStack = IRB.CreateLoad(SanCovLowestStack);
auto IsStackLower = IRB.CreateICmpULT(FrameAddrInt, LowestStack);
auto ThenTerm = SplitBlockAndInsertIfThen(IsStackLower, &*IP, false);
IRBuilder<> ThenIRB(ThenTerm);
auto Store = ThenIRB.CreateStore(FrameAddrInt, SanCovLowestStack);
SetNoSanitizeMetadata(LowestStack);
SetNoSanitizeMetadata(Store);
}
}
std::string
SanitizerCoverageModule::getSectionName(const std::string &Section) const {
if (TargetTriple.getObjectFormat() == Triple::COFF) {
if (Section == SanCovCountersSectionName)
return ".SCOV$CM";
if (Section == SanCovPCsSectionName)
return ".SCOVP$M";
return ".SCOV$GM"; // For SanCovGuardsSectionName.
}
if (TargetTriple.isOSBinFormatMachO())
return "__DATA,__" + Section;
return "__" + Section;
}
std::string
SanitizerCoverageModule::getSectionStart(const std::string &Section) const {
if (TargetTriple.isOSBinFormatMachO())
return "\1section$start$__DATA$__" + Section;
return "__start___" + Section;
}
std::string
SanitizerCoverageModule::getSectionEnd(const std::string &Section) const {
if (TargetTriple.isOSBinFormatMachO())
return "\1section$end$__DATA$__" + Section;
return "__stop___" + Section;
}
char SanitizerCoverageModule::ID = 0;
INITIALIZE_PASS_BEGIN(SanitizerCoverageModule, "sancov",
"SanitizerCoverage: TODO."
"ModulePass",
false, false)
INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
INITIALIZE_PASS_DEPENDENCY(PostDominatorTreeWrapperPass)
INITIALIZE_PASS_END(SanitizerCoverageModule, "sancov",
"SanitizerCoverage: TODO."
"ModulePass",
false, false)
ModulePass *llvm::createSanitizerCoverageModulePass(
const SanitizerCoverageOptions &Options) {
return new SanitizerCoverageModule(Options);
}
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