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clang-p2996/mlir/lib/Conversion/FuncToLLVM/FuncToLLVM.cpp
Jeff Niu 53406427cd [mlir] FunctionOpInterface: turn required attributes into interface methods (Reland) 
Reland D139447, D139471 With flang actually working

- FunctionOpInterface: make get/setFunctionType interface methods

This patch removes the concept of a `function_type`-named type attribute
as a requirement for implementors of FunctionOpInterface. Instead, this
type should be provided through two interface methods, `getFunctionType`
and `setFunctionTypeAttr` (*Attr because functions may use different
concrete function types), which should be automatically implemented by
ODS for ops that define a `$function_type` attribute.

This also allows FunctionOpInterface to materialize function types if
they don't carry them in an attribute, for example.

Importantly, all the function "helper" still accept an attribute name to
use in parsing and printing functions, for example.

- FunctionOpInterface: arg and result attrs dispatch to interface

This patch removes the `arg_attrs` and `res_attrs` named attributes as a
requirement for FunctionOpInterface and replaces them with interface
methods for the getters, setters, and removers of the relevent
attributes. This allows operations to use their own storage for the
argument and result attributes.

Reviewed By: jpienaar

Differential Revision: https://reviews.llvm.org/D139736
2022-12-10 15:17:09 -08:00

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//===- FuncToLLVM.cpp - Func to LLVM dialect conversion -------------------===//
//
// 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 a pass to convert MLIR Func and builtin dialects
// into the LLVM IR dialect.
//
//===----------------------------------------------------------------------===//
#include "mlir/Conversion/FuncToLLVM/ConvertFuncToLLVMPass.h"
#include "mlir/Analysis/DataLayoutAnalysis.h"
#include "mlir/Conversion/ArithToLLVM/ArithToLLVM.h"
#include "mlir/Conversion/ControlFlowToLLVM/ControlFlowToLLVM.h"
#include "mlir/Conversion/FuncToLLVM/ConvertFuncToLLVM.h"
#include "mlir/Conversion/LLVMCommon/ConversionTarget.h"
#include "mlir/Conversion/LLVMCommon/Pattern.h"
#include "mlir/Conversion/LLVMCommon/VectorPattern.h"
#include "mlir/Dialect/Func/IR/FuncOps.h"
#include "mlir/Dialect/LLVMIR/FunctionCallUtils.h"
#include "mlir/Dialect/LLVMIR/LLVMDialect.h"
#include "mlir/Dialect/LLVMIR/LLVMTypes.h"
#include "mlir/Dialect/Utils/StaticValueUtils.h"
#include "mlir/IR/Attributes.h"
#include "mlir/IR/BlockAndValueMapping.h"
#include "mlir/IR/Builders.h"
#include "mlir/IR/BuiltinAttributeInterfaces.h"
#include "mlir/IR/BuiltinAttributes.h"
#include "mlir/IR/BuiltinOps.h"
#include "mlir/IR/PatternMatch.h"
#include "mlir/IR/TypeUtilities.h"
#include "mlir/Support/LogicalResult.h"
#include "mlir/Support/MathExtras.h"
#include "mlir/Transforms/DialectConversion.h"
#include "mlir/Transforms/Passes.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/TypeSwitch.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/Type.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/FormatVariadic.h"
#include <algorithm>
#include <functional>
namespace mlir {
#define GEN_PASS_DEF_CONVERTFUNCTOLLVM
#include "mlir/Conversion/Passes.h.inc"
} // namespace mlir
using namespace mlir;
#define PASS_NAME "convert-func-to-llvm"
/// Only retain those attributes that are not constructed by
/// `LLVMFuncOp::build`. If `filterArgAttrs` is set, also filter out argument
/// attributes.
static void filterFuncAttributes(func::FuncOp func, bool filterArgAndResAttrs,
SmallVectorImpl<NamedAttribute> &result) {
for (const NamedAttribute &attr : func->getAttrs()) {
if (attr.getName() == SymbolTable::getSymbolAttrName() ||
attr.getName() == func.getFunctionTypeAttrName() ||
attr.getName() == "func.varargs" ||
(filterArgAndResAttrs &&
(attr.getName() == func.getArgAttrsAttrName() ||
attr.getName() == func.getResAttrsAttrName())))
continue;
result.push_back(attr);
}
}
/// Helper function for wrapping all attributes into a single DictionaryAttr
static auto wrapAsStructAttrs(OpBuilder &b, ArrayAttr attrs) {
return DictionaryAttr::get(
b.getContext(),
b.getNamedAttr(LLVM::LLVMDialect::getStructAttrsAttrName(), attrs));
}
/// Combines all result attributes into a single DictionaryAttr
/// and prepends to argument attrs.
/// This is intended to be used to format the attributes for a C wrapper
/// function when the result(s) is converted to the first function argument
/// (in the multiple return case, all returns get wrapped into a single
/// argument). The total number of argument attributes should be equal to
/// (number of function arguments) + 1.
static void
prependResAttrsToArgAttrs(OpBuilder &builder,
SmallVectorImpl<NamedAttribute> &attributes,
func::FuncOp func) {
size_t numArguments = func.getNumArguments();
auto allAttrs = SmallVector<Attribute>(
numArguments + 1, DictionaryAttr::get(builder.getContext()));
NamedAttribute *argAttrs = nullptr;
for (auto *it = attributes.begin(); it != attributes.end();) {
if (it->getName() == func.getArgAttrsAttrName()) {
auto arrayAttrs = it->getValue().cast<ArrayAttr>();
assert(arrayAttrs.size() == numArguments &&
"Number of arg attrs and args should match");
std::copy(arrayAttrs.begin(), arrayAttrs.end(), allAttrs.begin() + 1);
argAttrs = it;
} else if (it->getName() == func.getResAttrsAttrName()) {
auto arrayAttrs = it->getValue().cast<ArrayAttr>();
assert(!arrayAttrs.empty() && "expected array to be non-empty");
allAttrs[0] = (arrayAttrs.size() == 1)
? arrayAttrs[0]
: wrapAsStructAttrs(builder, arrayAttrs);
it = attributes.erase(it);
continue;
}
it++;
}
auto newArgAttrs = builder.getNamedAttr(func.getArgAttrsAttrName(),
builder.getArrayAttr(allAttrs));
if (!argAttrs) {
attributes.emplace_back(newArgAttrs);
return;
}
*argAttrs = newArgAttrs;
}
/// Creates an auxiliary function with pointer-to-memref-descriptor-struct
/// arguments instead of unpacked arguments. This function can be called from C
/// by passing a pointer to a C struct corresponding to a memref descriptor.
/// Similarly, returned memrefs are passed via pointers to a C struct that is
/// passed as additional argument.
/// Internally, the auxiliary function unpacks the descriptor into individual
/// components and forwards them to `newFuncOp` and forwards the results to
/// the extra arguments.
static void wrapForExternalCallers(OpBuilder &rewriter, Location loc,
LLVMTypeConverter &typeConverter,
func::FuncOp funcOp,
LLVM::LLVMFuncOp newFuncOp) {
auto type = funcOp.getFunctionType();
SmallVector<NamedAttribute, 4> attributes;
filterFuncAttributes(funcOp, /*filterArgAndResAttrs=*/false, attributes);
auto [wrapperFuncType, resultIsNowArg] =
typeConverter.convertFunctionTypeCWrapper(type);
if (resultIsNowArg)
prependResAttrsToArgAttrs(rewriter, attributes, funcOp);
auto wrapperFuncOp = rewriter.create<LLVM::LLVMFuncOp>(
loc, llvm::formatv("_mlir_ciface_{0}", funcOp.getName()).str(),
wrapperFuncType, LLVM::Linkage::External, /*dsoLocal*/ false,
/*cconv*/ LLVM::CConv::C, attributes);
OpBuilder::InsertionGuard guard(rewriter);
rewriter.setInsertionPointToStart(wrapperFuncOp.addEntryBlock());
SmallVector<Value, 8> args;
size_t argOffset = resultIsNowArg ? 1 : 0;
for (auto &en : llvm::enumerate(type.getInputs())) {
Value arg = wrapperFuncOp.getArgument(en.index() + argOffset);
if (auto memrefType = en.value().dyn_cast<MemRefType>()) {
Value loaded = rewriter.create<LLVM::LoadOp>(loc, arg);
MemRefDescriptor::unpack(rewriter, loc, loaded, memrefType, args);
continue;
}
if (en.value().isa<UnrankedMemRefType>()) {
Value loaded = rewriter.create<LLVM::LoadOp>(loc, arg);
UnrankedMemRefDescriptor::unpack(rewriter, loc, loaded, args);
continue;
}
args.push_back(arg);
}
auto call = rewriter.create<LLVM::CallOp>(loc, newFuncOp, args);
if (resultIsNowArg) {
rewriter.create<LLVM::StoreOp>(loc, call.getResult(),
wrapperFuncOp.getArgument(0));
rewriter.create<LLVM::ReturnOp>(loc, ValueRange{});
} else {
rewriter.create<LLVM::ReturnOp>(loc, call.getResults());
}
}
/// Creates an auxiliary function with pointer-to-memref-descriptor-struct
/// arguments instead of unpacked arguments. Creates a body for the (external)
/// `newFuncOp` that allocates a memref descriptor on stack, packs the
/// individual arguments into this descriptor and passes a pointer to it into
/// the auxiliary function. If the result of the function cannot be directly
/// returned, we write it to a special first argument that provides a pointer
/// to a corresponding struct. This auxiliary external function is now
/// compatible with functions defined in C using pointers to C structs
/// corresponding to a memref descriptor.
static void wrapExternalFunction(OpBuilder &builder, Location loc,
LLVMTypeConverter &typeConverter,
func::FuncOp funcOp,
LLVM::LLVMFuncOp newFuncOp) {
OpBuilder::InsertionGuard guard(builder);
auto [wrapperType, resultIsNowArg] =
typeConverter.convertFunctionTypeCWrapper(funcOp.getFunctionType());
// This conversion can only fail if it could not convert one of the argument
// types. But since it has been applied to a non-wrapper function before, it
// should have failed earlier and not reach this point at all.
assert(wrapperType && "unexpected type conversion failure");
SmallVector<NamedAttribute, 4> attributes;
filterFuncAttributes(funcOp, /*filterArgAndResAttrs=*/false, attributes);
if (resultIsNowArg)
prependResAttrsToArgAttrs(builder, attributes, funcOp);
// Create the auxiliary function.
auto wrapperFunc = builder.create<LLVM::LLVMFuncOp>(
loc, llvm::formatv("_mlir_ciface_{0}", funcOp.getName()).str(),
wrapperType, LLVM::Linkage::External, /*dsoLocal*/ false,
/*cconv*/ LLVM::CConv::C, attributes);
builder.setInsertionPointToStart(newFuncOp.addEntryBlock());
// Get a ValueRange containing arguments.
FunctionType type = funcOp.getFunctionType();
SmallVector<Value, 8> args;
args.reserve(type.getNumInputs());
ValueRange wrapperArgsRange(newFuncOp.getArguments());
if (resultIsNowArg) {
// Allocate the struct on the stack and pass the pointer.
Type resultType =
wrapperType.cast<LLVM::LLVMFunctionType>().getParamType(0);
Value one = builder.create<LLVM::ConstantOp>(
loc, typeConverter.convertType(builder.getIndexType()),
builder.getIntegerAttr(builder.getIndexType(), 1));
Value result = builder.create<LLVM::AllocaOp>(loc, resultType, one);
args.push_back(result);
}
// Iterate over the inputs of the original function and pack values into
// memref descriptors if the original type is a memref.
for (auto &en : llvm::enumerate(type.getInputs())) {
Value arg;
int numToDrop = 1;
auto memRefType = en.value().dyn_cast<MemRefType>();
auto unrankedMemRefType = en.value().dyn_cast<UnrankedMemRefType>();
if (memRefType || unrankedMemRefType) {
numToDrop = memRefType
? MemRefDescriptor::getNumUnpackedValues(memRefType)
: UnrankedMemRefDescriptor::getNumUnpackedValues();
Value packed =
memRefType
? MemRefDescriptor::pack(builder, loc, typeConverter, memRefType,
wrapperArgsRange.take_front(numToDrop))
: UnrankedMemRefDescriptor::pack(
builder, loc, typeConverter, unrankedMemRefType,
wrapperArgsRange.take_front(numToDrop));
auto ptrTy = LLVM::LLVMPointerType::get(packed.getType());
Value one = builder.create<LLVM::ConstantOp>(
loc, typeConverter.convertType(builder.getIndexType()),
builder.getIntegerAttr(builder.getIndexType(), 1));
Value allocated =
builder.create<LLVM::AllocaOp>(loc, ptrTy, one, /*alignment=*/0);
builder.create<LLVM::StoreOp>(loc, packed, allocated);
arg = allocated;
} else {
arg = wrapperArgsRange[0];
}
args.push_back(arg);
wrapperArgsRange = wrapperArgsRange.drop_front(numToDrop);
}
assert(wrapperArgsRange.empty() && "did not map some of the arguments");
auto call = builder.create<LLVM::CallOp>(loc, wrapperFunc, args);
if (resultIsNowArg) {
Value result = builder.create<LLVM::LoadOp>(loc, args.front());
builder.create<LLVM::ReturnOp>(loc, result);
} else {
builder.create<LLVM::ReturnOp>(loc, call.getResults());
}
}
namespace {
struct FuncOpConversionBase : public ConvertOpToLLVMPattern<func::FuncOp> {
protected:
using ConvertOpToLLVMPattern<func::FuncOp>::ConvertOpToLLVMPattern;
// Convert input FuncOp to LLVMFuncOp by using the LLVMTypeConverter provided
// to this legalization pattern.
LLVM::LLVMFuncOp
convertFuncOpToLLVMFuncOp(func::FuncOp funcOp,
ConversionPatternRewriter &rewriter) const {
// Convert the original function arguments. They are converted using the
// LLVMTypeConverter provided to this legalization pattern.
auto varargsAttr = funcOp->getAttrOfType<BoolAttr>("func.varargs");
TypeConverter::SignatureConversion result(funcOp.getNumArguments());
auto llvmType = getTypeConverter()->convertFunctionSignature(
funcOp.getFunctionType(), varargsAttr && varargsAttr.getValue(),
result);
if (!llvmType)
return nullptr;
// Propagate argument/result attributes to all converted arguments/result
// obtained after converting a given original argument/result.
SmallVector<NamedAttribute, 4> attributes;
filterFuncAttributes(funcOp, /*filterArgAndResAttrs=*/true, attributes);
if (ArrayAttr resAttrDicts = funcOp.getAllResultAttrs()) {
assert(!resAttrDicts.empty() && "expected array to be non-empty");
auto newResAttrDicts =
(funcOp.getNumResults() == 1)
? resAttrDicts
: rewriter.getArrayAttr(
{wrapAsStructAttrs(rewriter, resAttrDicts)});
attributes.push_back(
rewriter.getNamedAttr(funcOp.getResAttrsAttrName(), newResAttrDicts));
}
if (ArrayAttr argAttrDicts = funcOp.getAllArgAttrs()) {
SmallVector<Attribute, 4> newArgAttrs(
llvmType.cast<LLVM::LLVMFunctionType>().getNumParams());
for (unsigned i = 0, e = funcOp.getNumArguments(); i < e; ++i) {
// Some LLVM IR attribute have a type attached to them. During FuncOp ->
// LLVMFuncOp conversion these types may have changed. Account for that
// change by converting attributes' types as well.
SmallVector<NamedAttribute, 4> convertedAttrs;
auto attrsDict = argAttrDicts[i].cast<DictionaryAttr>();
convertedAttrs.reserve(attrsDict.size());
for (const NamedAttribute &attr : attrsDict) {
const auto convert = [&](const NamedAttribute &attr) {
return TypeAttr::get(getTypeConverter()->convertType(
attr.getValue().cast<TypeAttr>().getValue()));
};
if (attr.getName().getValue() ==
LLVM::LLVMDialect::getByValAttrName()) {
convertedAttrs.push_back(rewriter.getNamedAttr(
LLVM::LLVMDialect::getByValAttrName(), convert(attr)));
} else if (attr.getName().getValue() ==
LLVM::LLVMDialect::getByRefAttrName()) {
convertedAttrs.push_back(rewriter.getNamedAttr(
LLVM::LLVMDialect::getByRefAttrName(), convert(attr)));
} else if (attr.getName().getValue() ==
LLVM::LLVMDialect::getStructRetAttrName()) {
convertedAttrs.push_back(rewriter.getNamedAttr(
LLVM::LLVMDialect::getStructRetAttrName(), convert(attr)));
} else if (attr.getName().getValue() ==
LLVM::LLVMDialect::getInAllocaAttrName()) {
convertedAttrs.push_back(rewriter.getNamedAttr(
LLVM::LLVMDialect::getInAllocaAttrName(), convert(attr)));
} else {
convertedAttrs.push_back(attr);
}
}
auto mapping = result.getInputMapping(i);
assert(mapping && "unexpected deletion of function argument");
for (size_t j = 0; j < mapping->size; ++j)
newArgAttrs[mapping->inputNo + j] =
DictionaryAttr::get(rewriter.getContext(), convertedAttrs);
}
attributes.push_back(rewriter.getNamedAttr(
funcOp.getArgAttrsAttrName(), rewriter.getArrayAttr(newArgAttrs)));
}
for (const auto &pair : llvm::enumerate(attributes)) {
if (pair.value().getName() == "llvm.linkage") {
attributes.erase(attributes.begin() + pair.index());
break;
}
}
// Create an LLVM function, use external linkage by default until MLIR
// functions have linkage.
LLVM::Linkage linkage = LLVM::Linkage::External;
if (funcOp->hasAttr("llvm.linkage")) {
auto attr =
funcOp->getAttr("llvm.linkage").dyn_cast<mlir::LLVM::LinkageAttr>();
if (!attr) {
funcOp->emitError()
<< "Contains llvm.linkage attribute not of type LLVM::LinkageAttr";
return nullptr;
}
linkage = attr.getLinkage();
}
auto newFuncOp = rewriter.create<LLVM::LLVMFuncOp>(
funcOp.getLoc(), funcOp.getName(), llvmType, linkage,
/*dsoLocal*/ false, /*cconv*/ LLVM::CConv::C, attributes);
rewriter.inlineRegionBefore(funcOp.getBody(), newFuncOp.getBody(),
newFuncOp.end());
if (failed(rewriter.convertRegionTypes(&newFuncOp.getBody(), *typeConverter,
&result)))
return nullptr;
return newFuncOp;
}
};
/// FuncOp legalization pattern that converts MemRef arguments to pointers to
/// MemRef descriptors (LLVM struct data types) containing all the MemRef type
/// information.
struct FuncOpConversion : public FuncOpConversionBase {
FuncOpConversion(LLVMTypeConverter &converter)
: FuncOpConversionBase(converter) {}
LogicalResult
matchAndRewrite(func::FuncOp funcOp, OpAdaptor adaptor,
ConversionPatternRewriter &rewriter) const override {
auto newFuncOp = convertFuncOpToLLVMFuncOp(funcOp, rewriter);
if (!newFuncOp)
return failure();
if (funcOp->getAttrOfType<UnitAttr>(
LLVM::LLVMDialect::getEmitCWrapperAttrName())) {
if (newFuncOp.isVarArg())
return funcOp->emitError("C interface for variadic functions is not "
"supported yet.");
if (newFuncOp.isExternal())
wrapExternalFunction(rewriter, funcOp.getLoc(), *getTypeConverter(),
funcOp, newFuncOp);
else
wrapForExternalCallers(rewriter, funcOp.getLoc(), *getTypeConverter(),
funcOp, newFuncOp);
}
rewriter.eraseOp(funcOp);
return success();
}
};
/// FuncOp legalization pattern that converts MemRef arguments to bare pointers
/// to the MemRef element type. This will impact the calling convention and ABI.
struct BarePtrFuncOpConversion : public FuncOpConversionBase {
using FuncOpConversionBase::FuncOpConversionBase;
LogicalResult
matchAndRewrite(func::FuncOp funcOp, OpAdaptor adaptor,
ConversionPatternRewriter &rewriter) const override {
// TODO: bare ptr conversion could be handled by argument materialization
// and most of the code below would go away. But to do this, we would need a
// way to distinguish between FuncOp and other regions in the
// addArgumentMaterialization hook.
// Store the type of memref-typed arguments before the conversion so that we
// can promote them to MemRef descriptor at the beginning of the function.
SmallVector<Type, 8> oldArgTypes =
llvm::to_vector<8>(funcOp.getFunctionType().getInputs());
auto newFuncOp = convertFuncOpToLLVMFuncOp(funcOp, rewriter);
if (!newFuncOp)
return failure();
if (newFuncOp.getBody().empty()) {
rewriter.eraseOp(funcOp);
return success();
}
// Promote bare pointers from memref arguments to memref descriptors at the
// beginning of the function so that all the memrefs in the function have a
// uniform representation.
Block *entryBlock = &newFuncOp.getBody().front();
auto blockArgs = entryBlock->getArguments();
assert(blockArgs.size() == oldArgTypes.size() &&
"The number of arguments and types doesn't match");
OpBuilder::InsertionGuard guard(rewriter);
rewriter.setInsertionPointToStart(entryBlock);
for (auto it : llvm::zip(blockArgs, oldArgTypes)) {
BlockArgument arg = std::get<0>(it);
Type argTy = std::get<1>(it);
// Unranked memrefs are not supported in the bare pointer calling
// convention. We should have bailed out before in the presence of
// unranked memrefs.
assert(!argTy.isa<UnrankedMemRefType>() &&
"Unranked memref is not supported");
auto memrefTy = argTy.dyn_cast<MemRefType>();
if (!memrefTy)
continue;
// Replace barePtr with a placeholder (undef), promote barePtr to a ranked
// or unranked memref descriptor and replace placeholder with the last
// instruction of the memref descriptor.
// TODO: The placeholder is needed to avoid replacing barePtr uses in the
// MemRef descriptor instructions. We may want to have a utility in the
// rewriter to properly handle this use case.
Location loc = funcOp.getLoc();
auto placeholder = rewriter.create<LLVM::UndefOp>(
loc, getTypeConverter()->convertType(memrefTy));
rewriter.replaceUsesOfBlockArgument(arg, placeholder);
Value desc = MemRefDescriptor::fromStaticShape(
rewriter, loc, *getTypeConverter(), memrefTy, arg);
rewriter.replaceOp(placeholder, {desc});
}
rewriter.eraseOp(funcOp);
return success();
}
};
struct ConstantOpLowering : public ConvertOpToLLVMPattern<func::ConstantOp> {
using ConvertOpToLLVMPattern<func::ConstantOp>::ConvertOpToLLVMPattern;
LogicalResult
matchAndRewrite(func::ConstantOp op, OpAdaptor adaptor,
ConversionPatternRewriter &rewriter) const override {
auto type = typeConverter->convertType(op.getResult().getType());
if (!type || !LLVM::isCompatibleType(type))
return rewriter.notifyMatchFailure(op, "failed to convert result type");
auto newOp =
rewriter.create<LLVM::AddressOfOp>(op.getLoc(), type, op.getValue());
for (const NamedAttribute &attr : op->getAttrs()) {
if (attr.getName().strref() == "value")
continue;
newOp->setAttr(attr.getName(), attr.getValue());
}
rewriter.replaceOp(op, newOp->getResults());
return success();
}
};
// A CallOp automatically promotes MemRefType to a sequence of alloca/store and
// passes the pointer to the MemRef across function boundaries.
template <typename CallOpType>
struct CallOpInterfaceLowering : public ConvertOpToLLVMPattern<CallOpType> {
using ConvertOpToLLVMPattern<CallOpType>::ConvertOpToLLVMPattern;
using Super = CallOpInterfaceLowering<CallOpType>;
using Base = ConvertOpToLLVMPattern<CallOpType>;
LogicalResult
matchAndRewrite(CallOpType callOp, typename CallOpType::Adaptor adaptor,
ConversionPatternRewriter &rewriter) const override {
// Pack the result types into a struct.
Type packedResult = nullptr;
unsigned numResults = callOp.getNumResults();
auto resultTypes = llvm::to_vector<4>(callOp.getResultTypes());
if (numResults != 0) {
if (!(packedResult =
this->getTypeConverter()->packFunctionResults(resultTypes)))
return failure();
}
auto promoted = this->getTypeConverter()->promoteOperands(
callOp.getLoc(), /*opOperands=*/callOp->getOperands(),
adaptor.getOperands(), rewriter);
auto newOp = rewriter.create<LLVM::CallOp>(
callOp.getLoc(), packedResult ? TypeRange(packedResult) : TypeRange(),
promoted, callOp->getAttrs());
SmallVector<Value, 4> results;
if (numResults < 2) {
// If < 2 results, packing did not do anything and we can just return.
results.append(newOp.result_begin(), newOp.result_end());
} else {
// Otherwise, it had been converted to an operation producing a structure.
// Extract individual results from the structure and return them as list.
results.reserve(numResults);
for (unsigned i = 0; i < numResults; ++i) {
results.push_back(rewriter.create<LLVM::ExtractValueOp>(
callOp.getLoc(), newOp->getResult(0), i));
}
}
if (this->getTypeConverter()->getOptions().useBarePtrCallConv) {
// For the bare-ptr calling convention, promote memref results to
// descriptors.
assert(results.size() == resultTypes.size() &&
"The number of arguments and types doesn't match");
this->getTypeConverter()->promoteBarePtrsToDescriptors(
rewriter, callOp.getLoc(), resultTypes, results);
} else if (failed(this->copyUnrankedDescriptors(rewriter, callOp.getLoc(),
resultTypes, results,
/*toDynamic=*/false))) {
return failure();
}
rewriter.replaceOp(callOp, results);
return success();
}
};
struct CallOpLowering : public CallOpInterfaceLowering<func::CallOp> {
using Super::Super;
};
struct CallIndirectOpLowering
: public CallOpInterfaceLowering<func::CallIndirectOp> {
using Super::Super;
};
struct UnrealizedConversionCastOpLowering
: public ConvertOpToLLVMPattern<UnrealizedConversionCastOp> {
using ConvertOpToLLVMPattern<
UnrealizedConversionCastOp>::ConvertOpToLLVMPattern;
LogicalResult
matchAndRewrite(UnrealizedConversionCastOp op, OpAdaptor adaptor,
ConversionPatternRewriter &rewriter) const override {
SmallVector<Type> convertedTypes;
if (succeeded(typeConverter->convertTypes(op.getOutputs().getTypes(),
convertedTypes)) &&
convertedTypes == adaptor.getInputs().getTypes()) {
rewriter.replaceOp(op, adaptor.getInputs());
return success();
}
convertedTypes.clear();
if (succeeded(typeConverter->convertTypes(adaptor.getInputs().getTypes(),
convertedTypes)) &&
convertedTypes == op.getOutputs().getType()) {
rewriter.replaceOp(op, adaptor.getInputs());
return success();
}
return failure();
}
};
// Special lowering pattern for `ReturnOps`. Unlike all other operations,
// `ReturnOp` interacts with the function signature and must have as many
// operands as the function has return values. Because in LLVM IR, functions
// can only return 0 or 1 value, we pack multiple values into a structure type.
// Emit `UndefOp` followed by `InsertValueOp`s to create such structure if
// necessary before returning it
struct ReturnOpLowering : public ConvertOpToLLVMPattern<func::ReturnOp> {
using ConvertOpToLLVMPattern<func::ReturnOp>::ConvertOpToLLVMPattern;
LogicalResult
matchAndRewrite(func::ReturnOp op, OpAdaptor adaptor,
ConversionPatternRewriter &rewriter) const override {
Location loc = op.getLoc();
unsigned numArguments = op.getNumOperands();
SmallVector<Value, 4> updatedOperands;
if (getTypeConverter()->getOptions().useBarePtrCallConv) {
// For the bare-ptr calling convention, extract the aligned pointer to
// be returned from the memref descriptor.
for (auto it : llvm::zip(op->getOperands(), adaptor.getOperands())) {
Type oldTy = std::get<0>(it).getType();
Value newOperand = std::get<1>(it);
if (oldTy.isa<MemRefType>() && getTypeConverter()->canConvertToBarePtr(
oldTy.cast<BaseMemRefType>())) {
MemRefDescriptor memrefDesc(newOperand);
newOperand = memrefDesc.alignedPtr(rewriter, loc);
} else if (oldTy.isa<UnrankedMemRefType>()) {
// Unranked memref is not supported in the bare pointer calling
// convention.
return failure();
}
updatedOperands.push_back(newOperand);
}
} else {
updatedOperands = llvm::to_vector<4>(adaptor.getOperands());
(void)copyUnrankedDescriptors(rewriter, loc, op.getOperands().getTypes(),
updatedOperands,
/*toDynamic=*/true);
}
// If ReturnOp has 0 or 1 operand, create it and return immediately.
if (numArguments <= 1) {
rewriter.replaceOpWithNewOp<LLVM::ReturnOp>(
op, TypeRange(), updatedOperands, op->getAttrs());
return success();
}
// Otherwise, we need to pack the arguments into an LLVM struct type before
// returning.
auto packedType =
getTypeConverter()->packFunctionResults(op.getOperandTypes());
Value packed = rewriter.create<LLVM::UndefOp>(loc, packedType);
for (auto &it : llvm::enumerate(updatedOperands)) {
packed = rewriter.create<LLVM::InsertValueOp>(loc, packed, it.value(),
it.index());
}
rewriter.replaceOpWithNewOp<LLVM::ReturnOp>(op, TypeRange(), packed,
op->getAttrs());
return success();
}
};
} // namespace
void mlir::populateFuncToLLVMFuncOpConversionPattern(
LLVMTypeConverter &converter, RewritePatternSet &patterns) {
if (converter.getOptions().useBarePtrCallConv)
patterns.add<BarePtrFuncOpConversion>(converter);
else
patterns.add<FuncOpConversion>(converter);
}
void mlir::populateFuncToLLVMConversionPatterns(LLVMTypeConverter &converter,
RewritePatternSet &patterns) {
populateFuncToLLVMFuncOpConversionPattern(converter, patterns);
// clang-format off
patterns.add<
CallIndirectOpLowering,
CallOpLowering,
ConstantOpLowering,
ReturnOpLowering>(converter);
// clang-format on
}
namespace {
/// A pass converting Func operations into the LLVM IR dialect.
struct ConvertFuncToLLVMPass
: public impl::ConvertFuncToLLVMBase<ConvertFuncToLLVMPass> {
ConvertFuncToLLVMPass() = default;
ConvertFuncToLLVMPass(bool useBarePtrCallConv, unsigned indexBitwidth,
bool useAlignedAlloc,
const llvm::DataLayout &dataLayout) {
this->useBarePtrCallConv = useBarePtrCallConv;
this->indexBitwidth = indexBitwidth;
this->dataLayout = dataLayout.getStringRepresentation();
}
/// Run the dialect converter on the module.
void runOnOperation() override {
if (failed(LLVM::LLVMDialect::verifyDataLayoutString(
this->dataLayout, [this](const Twine &message) {
getOperation().emitError() << message.str();
}))) {
signalPassFailure();
return;
}
ModuleOp m = getOperation();
const auto &dataLayoutAnalysis = getAnalysis<DataLayoutAnalysis>();
LowerToLLVMOptions options(&getContext(),
dataLayoutAnalysis.getAtOrAbove(m));
options.useBarePtrCallConv = useBarePtrCallConv;
if (indexBitwidth != kDeriveIndexBitwidthFromDataLayout)
options.overrideIndexBitwidth(indexBitwidth);
options.dataLayout = llvm::DataLayout(this->dataLayout);
LLVMTypeConverter typeConverter(&getContext(), options,
&dataLayoutAnalysis);
RewritePatternSet patterns(&getContext());
populateFuncToLLVMConversionPatterns(typeConverter, patterns);
// TODO: Remove these in favor of their dedicated conversion passes.
arith::populateArithToLLVMConversionPatterns(typeConverter, patterns);
cf::populateControlFlowToLLVMConversionPatterns(typeConverter, patterns);
LLVMConversionTarget target(getContext());
if (failed(applyPartialConversion(m, target, std::move(patterns))))
signalPassFailure();
m->setAttr(LLVM::LLVMDialect::getDataLayoutAttrName(),
StringAttr::get(m.getContext(), this->dataLayout));
}
};
} // namespace
std::unique_ptr<OperationPass<ModuleOp>> mlir::createConvertFuncToLLVMPass() {
return std::make_unique<ConvertFuncToLLVMPass>();
}
std::unique_ptr<OperationPass<ModuleOp>>
mlir::createConvertFuncToLLVMPass(const LowerToLLVMOptions &options) {
auto allocLowering = options.allocLowering;
// There is no way to provide additional patterns for pass, so
// AllocLowering::None will always fail.
assert(allocLowering != LowerToLLVMOptions::AllocLowering::None &&
"ConvertFuncToLLVMPass doesn't support AllocLowering::None");
bool useAlignedAlloc =
(allocLowering == LowerToLLVMOptions::AllocLowering::AlignedAlloc);
return std::make_unique<ConvertFuncToLLVMPass>(
options.useBarePtrCallConv, options.getIndexBitwidth(), useAlignedAlloc,
options.dataLayout);
}
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