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[CIR][NFC] move data member pointer lowering to CXXABI
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This patch moves the lowering code for data member pointers from the conversion
patterns to the implementation of CXXABI because this part should be ABI-
specific.
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@Lancern
Lancern committed Nov 23, 2024
1 parent 4aca8d4 commit 94f8d28
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Showing 5 changed files with 159 additions and 55 deletions.
26 changes: 26 additions & 0 deletions clang/lib/CIR/Dialect/Transforms/TargetLowering/CIRCXXABI.h
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Original file line number Diff line number Diff line change
Expand Up @@ -15,9 +15,15 @@
#define LLVM_CLANG_LIB_CIR_DIALECT_TRANSFORMS_TARGETLOWERING_CIRCXXABI_H

#include "LowerFunctionInfo.h"
#include "mlir/IR/Attributes.h"
#include "mlir/IR/Types.h"
#include "mlir/IR/Value.h"
#include "mlir/Interfaces/DataLayoutInterfaces.h"
#include "mlir/Transforms/DialectConversion.h"
#include "clang/CIR/Dialect/Builder/CIRBaseBuilder.h"
#include "clang/CIR/Dialect/IR/CIRAttrs.h"
#include "clang/CIR/Dialect/IR/CIRDataLayout.h"
#include "clang/CIR/Dialect/IR/CIRTypes.h"
#include "clang/CIR/Target/AArch64.h"

namespace cir {
Expand Down Expand Up @@ -59,6 +65,26 @@ class CIRCXXABI {
/// Returns how an argument of the given record type should be passed.
/// FIXME(cir): This expects a CXXRecordDecl! Not any record type.
virtual RecordArgABI getRecordArgABI(const StructType RD) const = 0;

/// Lower the given data member pointer type to its ABI type. The returned
/// type is also a CIR type.
virtual mlir::Type
lowerDataMemberType(cir::DataMemberType type,
const mlir::TypeConverter &typeConverter) const = 0;

/// Lower the given data member pointer constant to a constant of the ABI
/// type. The returned constant is represented as an attribute as well.
virtual mlir::TypedAttr
lowerDataMemberConstant(cir::DataMemberAttr attr,
const mlir::DataLayout &layout,
const mlir::TypeConverter &typeConverter) const = 0;

/// Lower the given cir.get_runtime_member op to a sequence of more
/// "primitive" CIR operations that act on the ABI types.
virtual mlir::Operation *
lowerGetRuntimeMember(cir::GetRuntimeMemberOp op, mlir::Type loweredResultTy,
mlir::Value loweredAddr, mlir::Value loweredMember,
mlir::OpBuilder &builder) const = 0;
};

/// Creates an Itanium-family ABI.
Expand Down
62 changes: 62 additions & 0 deletions clang/lib/CIR/Dialect/Transforms/TargetLowering/ItaniumCXXABI.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -23,6 +23,7 @@
#include "../LoweringPrepareCXXABI.h"
#include "CIRCXXABI.h"
#include "LowerModule.h"
#include "mlir/Dialect/LLVMIR/LLVMDialect.h"
#include "llvm/Support/ErrorHandling.h"

namespace cir {
Expand Down Expand Up @@ -51,6 +52,19 @@ class ItaniumCXXABI : public CIRCXXABI {
cir_cconv_assert(!cir::MissingFeatures::recordDeclCanPassInRegisters());
return RAA_Default;
}

mlir::Type
lowerDataMemberType(cir::DataMemberType type,
const mlir::TypeConverter &typeConverter) const override;

mlir::TypedAttr lowerDataMemberConstant(
cir::DataMemberAttr attr, const mlir::DataLayout &layout,
const mlir::TypeConverter &typeConverter) const override;

mlir::Operation *
lowerGetRuntimeMember(cir::GetRuntimeMemberOp op, mlir::Type loweredResultTy,
mlir::Value loweredAddr, mlir::Value loweredMember,
mlir::OpBuilder &builder) const override;
};

} // namespace
Expand All @@ -67,6 +81,54 @@ bool ItaniumCXXABI::classifyReturnType(LowerFunctionInfo &FI) const {
return false;
}

mlir::Type ItaniumCXXABI::lowerDataMemberType(
cir::DataMemberType type, const mlir::TypeConverter &typeConverter) const {
// Itanium C++ ABI 2.3:
// A pointer to data member is an offset from the base address of
// the class object containing it, represented as a ptrdiff_t
const clang::TargetInfo &target = LM.getTarget();
clang::TargetInfo::IntType ptrdiffTy =
target.getPtrDiffType(clang::LangAS::Default);
return cir::IntType::get(type.getContext(), target.getTypeWidth(ptrdiffTy),
target.isTypeSigned(ptrdiffTy));
}

mlir::TypedAttr ItaniumCXXABI::lowerDataMemberConstant(
cir::DataMemberAttr attr, const mlir::DataLayout &layout,
const mlir::TypeConverter &typeConverter) const {
uint64_t memberOffset;
if (attr.isNullPtr()) {
// Itanium C++ ABI 2.3:
// A NULL pointer is represented as -1.
memberOffset = -1ull;
} else {
// Itanium C++ ABI 2.3:
// A pointer to data member is an offset from the base address of
// the class object containing it, represented as a ptrdiff_t
auto memberIndex = attr.getMemberIndex().value();
memberOffset =
attr.getType().getClsTy().getElementOffset(layout, memberIndex);
}

mlir::Type abiTy = lowerDataMemberType(attr.getType(), typeConverter);
return cir::IntAttr::get(abiTy, memberOffset);
}

mlir::Operation *ItaniumCXXABI::lowerGetRuntimeMember(
cir::GetRuntimeMemberOp op, mlir::Type loweredResultTy,
mlir::Value loweredAddr, mlir::Value loweredMember,
mlir::OpBuilder &builder) const {
auto byteTy = IntType::get(op.getContext(), 8, true);
auto bytePtrTy = PointerType::get(
byteTy, mlir::cast<PointerType>(op.getAddr().getType()).getAddrSpace());
auto objectBytesPtr = builder.create<CastOp>(op.getLoc(), bytePtrTy,
CastKind::bitcast, op.getAddr());
auto memberBytesPtr = builder.create<PtrStrideOp>(
op.getLoc(), bytePtrTy, objectBytesPtr, loweredMember);
return builder.create<CastOp>(op.getLoc(), op.getType(), CastKind::bitcast,
memberBytesPtr);
}

CIRCXXABI *CreateItaniumCXXABI(LowerModule &LM) {
switch (LM.getCXXABIKind()) {
// Note that AArch64 uses the generic ItaniumCXXABI class since it doesn't
Expand Down
74 changes: 33 additions & 41 deletions clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1521,28 +1521,6 @@ bool hasTrailingZeros(cir::ConstArrayAttr attr) {
}));
}

static mlir::Attribute
lowerDataMemberAttr(mlir::ModuleOp moduleOp, cir::DataMemberAttr attr,
const mlir::TypeConverter &typeConverter) {
mlir::DataLayout layout{moduleOp};

uint64_t memberOffset;
if (attr.isNullPtr()) {
// TODO(cir): the numerical value of a null data member pointer is
// ABI-specific and should be queried through ABI.
assert(!MissingFeatures::targetCodeGenInfoGetNullPointer());
memberOffset = -1ull;
} else {
auto memberIndex = attr.getMemberIndex().value();
memberOffset =
attr.getType().getClsTy().getElementOffset(layout, memberIndex);
}

auto underlyingIntTy = mlir::IntegerType::get(
moduleOp->getContext(), layout.getTypeSizeInBits(attr.getType()));
return mlir::IntegerAttr::get(underlyingIntTy, memberOffset);
}

mlir::LogicalResult CIRToLLVMConstantOpLowering::matchAndRewrite(
cir::ConstantOp op, OpAdaptor adaptor,
mlir::ConversionPatternRewriter &rewriter) const {
Expand Down Expand Up @@ -1602,9 +1580,13 @@ mlir::LogicalResult CIRToLLVMConstantOpLowering::matchAndRewrite(
}
attr = op.getValue();
} else if (mlir::isa<cir::DataMemberType>(op.getType())) {
assert(lowerMod && "lower module is not available");
auto dataMember = mlir::cast<cir::DataMemberAttr>(op.getValue());
attr = lowerDataMemberAttr(op->getParentOfType<mlir::ModuleOp>(),
dataMember, *typeConverter);
mlir::DataLayout layout(op->getParentOfType<mlir::ModuleOp>());
mlir::TypedAttr abiValue = lowerMod->getCXXABI().lowerDataMemberConstant(
dataMember, layout, *typeConverter);
rewriter.replaceOpWithNewOp<ConstantOp>(op, abiValue);
return mlir::success();
}
// TODO(cir): constant arrays are currently just pushed into the stack using
// the store instruction, instead of being stored as global variables and
Expand Down Expand Up @@ -2208,8 +2190,15 @@ mlir::LogicalResult CIRToLLVMGlobalOpLowering::matchAndRewrite(
return mlir::success();
} else if (auto dataMemberAttr =
mlir::dyn_cast<cir::DataMemberAttr>(init.value())) {
init = lowerDataMemberAttr(op->getParentOfType<mlir::ModuleOp>(),
dataMemberAttr, *typeConverter);
assert(lowerMod && "lower module is not available");
mlir::DataLayout layout(op->getParentOfType<mlir::ModuleOp>());
mlir::TypedAttr abiValue = lowerMod->getCXXABI().lowerDataMemberConstant(
dataMemberAttr, layout, *typeConverter);
auto abiOp = mlir::cast<GlobalOp>(rewriter.clone(*op.getOperation()));
abiOp.setInitialValueAttr(abiValue);
abiOp.setSymType(abiValue.getType());
rewriter.replaceOp(op, abiOp);
return mlir::success();
} else if (const auto structAttr =
mlir::dyn_cast<cir::ConstStructAttr>(init.value())) {
setupRegionInitializedLLVMGlobalOp(op, rewriter);
Expand Down Expand Up @@ -3237,11 +3226,11 @@ mlir::LogicalResult CIRToLLVMGetMemberOpLowering::matchAndRewrite(
mlir::LogicalResult CIRToLLVMGetRuntimeMemberOpLowering::matchAndRewrite(
cir::GetRuntimeMemberOp op, OpAdaptor adaptor,
mlir::ConversionPatternRewriter &rewriter) const {
auto llvmResTy = getTypeConverter()->convertType(op.getType());
auto llvmElementTy = mlir::IntegerType::get(op.getContext(), 8);

rewriter.replaceOpWithNewOp<mlir::LLVM::GEPOp>(
op, llvmResTy, llvmElementTy, adaptor.getAddr(), adaptor.getMember());
assert(lowerMod && "lowering module is not available");
mlir::Type llvmResTy = getTypeConverter()->convertType(op.getType());
mlir::Operation *llvmOp = lowerMod->getCXXABI().lowerGetRuntimeMember(
op, llvmResTy, adaptor.getAddr(), adaptor.getMember(), rewriter);
rewriter.replaceOp(op, llvmOp);
return mlir::success();
}

Expand Down Expand Up @@ -3850,14 +3839,17 @@ mlir::LogicalResult CIRToLLVMSignBitOpLowering::matchAndRewrite(

void populateCIRToLLVMConversionPatterns(
mlir::RewritePatternSet &patterns, mlir::TypeConverter &converter,
mlir::DataLayout &dataLayout,
mlir::DataLayout &dataLayout, cir::LowerModule *lowerModule,
llvm::StringMap<mlir::LLVM::GlobalOp> &stringGlobalsMap,
llvm::StringMap<mlir::LLVM::GlobalOp> &argStringGlobalsMap,
llvm::MapVector<mlir::ArrayAttr, mlir::LLVM::GlobalOp> &argsVarMap) {
patterns.add<CIRToLLVMReturnOpLowering>(patterns.getContext());
patterns.add<CIRToLLVMAllocaOpLowering>(converter, dataLayout,
stringGlobalsMap, argStringGlobalsMap,
argsVarMap, patterns.getContext());
patterns.add<CIRToLLVMConstantOpLowering, CIRToLLVMGlobalOpLowering,
CIRToLLVMGetRuntimeMemberOpLowering>(
converter, patterns.getContext(), lowerModule);
patterns.add<
// clang-format off
CIRToLLVMAbsOpLowering,
Expand Down Expand Up @@ -3891,7 +3883,6 @@ void populateCIRToLLVMConversionPatterns(
CIRToLLVMComplexImagPtrOpLowering,
CIRToLLVMComplexRealOpLowering,
CIRToLLVMComplexRealPtrOpLowering,
CIRToLLVMConstantOpLowering,
CIRToLLVMCopyOpLowering,
CIRToLLVMDerivedClassAddrOpLowering,
CIRToLLVMEhInflightOpLowering,
Expand All @@ -3902,8 +3893,6 @@ void populateCIRToLLVMConversionPatterns(
CIRToLLVMGetBitfieldOpLowering,
CIRToLLVMGetGlobalOpLowering,
CIRToLLVMGetMemberOpLowering,
CIRToLLVMGetRuntimeMemberOpLowering,
CIRToLLVMGlobalOpLowering,
CIRToLLVMInlineAsmOpLowering,
CIRToLLVMIsConstantOpLowering,
CIRToLLVMIsFPClassOpLowering,
Expand Down Expand Up @@ -3990,10 +3979,13 @@ void prepareTypeConverter(mlir::LLVMTypeConverter &converter,

return mlir::LLVM::LLVMPointerType::get(type.getContext(), targetAS);
});
converter.addConversion([&](cir::DataMemberType type) -> mlir::Type {
return mlir::IntegerType::get(type.getContext(),
dataLayout.getTypeSizeInBits(type));
});
converter.addConversion(
[&, lowerModule](cir::DataMemberType type) -> mlir::Type {
assert(lowerModule && "CXXABI is not available");
mlir::Type abiType =
lowerModule->getCXXABI().lowerDataMemberType(type, converter);
return converter.convertType(abiType);
});
converter.addConversion([&](cir::ArrayType type) -> mlir::Type {
auto ty = converter.convertType(type.getEltType());
return mlir::LLVM::LLVMArrayType::get(ty, type.getSize());
Expand Down Expand Up @@ -4328,8 +4320,8 @@ void ConvertCIRToLLVMPass::runOnOperation() {
llvm::MapVector<mlir::ArrayAttr, mlir::LLVM::GlobalOp> argsVarMap;

populateCIRToLLVMConversionPatterns(patterns, converter, dataLayout,
stringGlobalsMap, argStringGlobalsMap,
argsVarMap);
lowerModule.get(), stringGlobalsMap,
argStringGlobalsMap, argsVarMap);
mlir::populateFuncToLLVMConversionPatterns(converter, patterns);

mlir::ConversionTarget target(getContext());
Expand Down
25 changes: 22 additions & 3 deletions clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.h
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Original file line number Diff line number Diff line change
Expand Up @@ -291,8 +291,15 @@ class CIRToLLVMStoreOpLowering

class CIRToLLVMConstantOpLowering
: public mlir::OpConversionPattern<cir::ConstantOp> {
cir::LowerModule *lowerMod;

public:
using mlir::OpConversionPattern<cir::ConstantOp>::OpConversionPattern;
CIRToLLVMConstantOpLowering(const mlir::TypeConverter &typeConverter,
mlir::MLIRContext *context,
cir::LowerModule *lowerModule)
: OpConversionPattern(typeConverter, context), lowerMod(lowerModule) {
setHasBoundedRewriteRecursion();
}

mlir::LogicalResult
matchAndRewrite(cir::ConstantOp op, OpAdaptor,
Expand Down Expand Up @@ -490,8 +497,15 @@ class CIRToLLVMSwitchFlatOpLowering

class CIRToLLVMGlobalOpLowering
: public mlir::OpConversionPattern<cir::GlobalOp> {
cir::LowerModule *lowerMod;

public:
using mlir::OpConversionPattern<cir::GlobalOp>::OpConversionPattern;
CIRToLLVMGlobalOpLowering(const mlir::TypeConverter &typeConverter,
mlir::MLIRContext *context,
cir::LowerModule *lowerModule)
: OpConversionPattern(typeConverter, context), lowerMod(lowerModule) {
setHasBoundedRewriteRecursion();
}

mlir::LogicalResult
matchAndRewrite(cir::GlobalOp op, OpAdaptor,
Expand Down Expand Up @@ -774,8 +788,13 @@ class CIRToLLVMGetMemberOpLowering

class CIRToLLVMGetRuntimeMemberOpLowering
: public mlir::OpConversionPattern<cir::GetRuntimeMemberOp> {
cir::LowerModule *lowerMod;

public:
using mlir::OpConversionPattern<cir::GetRuntimeMemberOp>::OpConversionPattern;
CIRToLLVMGetRuntimeMemberOpLowering(const mlir::TypeConverter &typeConverter,
mlir::MLIRContext *context,
cir::LowerModule *lowerModule)
: OpConversionPattern(typeConverter, context), lowerMod(lowerModule) {}

mlir::LogicalResult
matchAndRewrite(cir::GetRuntimeMemberOp op, OpAdaptor,
Expand Down
27 changes: 16 additions & 11 deletions clang/test/CIR/Lowering/data-member.cir
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Original file line number Diff line number Diff line change
Expand Up @@ -5,7 +5,10 @@
!s64i = !cir.int<s, 64>
!structT = !cir.struct<struct "Point" {!cir.int<s, 32>, !cir.int<s, 32>, !cir.int<s, 32>}>

module @test {
module @test attributes {
cir.triple = "x86_64-unknown-linux-gnu",
llvm.data_layout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
} {
cir.global external @pt_member = #cir.data_member<1> : !cir.data_member<!s32i in !structT>
// MLIR: llvm.mlir.global external @pt_member(4 : i64) {addr_space = 0 : i32} : i64
// LLVM: @pt_member = global i64 4
Expand All @@ -15,8 +18,8 @@ module @test {
cir.return %0 : !cir.data_member<!s32i in !structT>
}
// MLIR: llvm.func @constant() -> i64
// MLIR-NEXT: %0 = llvm.mlir.constant(4 : i64) : i64
// MLIR-NEXT: llvm.return %0 : i64
// MLIR-NEXT: %[[#VAL:]] = llvm.mlir.constant(4 : i64) : i64
// MLIR-NEXT: llvm.return %[[#VAL]] : i64
// MLIR-NEXT: }

// LLVM: define i64 @constant()
Expand All @@ -28,8 +31,8 @@ module @test {
cir.return %0 : !cir.data_member<!s32i in !structT>
}
// MLIR: llvm.func @null_constant() -> i64
// MLIR-NEXT: %0 = llvm.mlir.constant(-1 : i64) : i64
// MLIR-NEXT: llvm.return %0 : i64
// MLIR-NEXT: %[[#VAL:]] = llvm.mlir.constant(-1 : i64) : i64
// MLIR-NEXT: llvm.return %[[#VAL]] : i64
// MLIR-NEXT: }

// LLVM: define i64 @null_constant() !dbg !7 {
Expand All @@ -40,13 +43,15 @@ module @test {
%0 = cir.get_runtime_member %arg0[%arg1 : !cir.data_member<!s32i in !structT>] : !cir.ptr<!structT> -> !cir.ptr<!s32i>
cir.return %0 : !cir.ptr<!s32i>
}
// MLIR: llvm.func @get_runtime_member(%arg0: !llvm.ptr, %arg1: i64) -> !llvm.ptr
// MLIR-NEXT: %0 = llvm.getelementptr %arg0[%arg1] : (!llvm.ptr, i64) -> !llvm.ptr, i8
// MLIR-NEXT: llvm.return %0 : !llvm.ptr
// MLIR: llvm.func @get_runtime_member(%[[ARG0:.+]]: !llvm.ptr, %[[ARG1:.+]]: i64) -> !llvm.ptr
// MLIR-NEXT: %[[#PTR:]] = llvm.bitcast %[[ARG0]] : !llvm.ptr to !llvm.ptr
// MLIR-NEXT: %[[#VAL:]] = llvm.getelementptr %[[#PTR]][%[[ARG1]]] : (!llvm.ptr, i64) -> !llvm.ptr, i8
// MLIR-NEXT: %[[#RET:]] = llvm.bitcast %[[#VAL]] : !llvm.ptr to !llvm.ptr
// MLIR-NEXT: llvm.return %[[#RET]] : !llvm.ptr
// MLIR-NEXT: }

// LLVM: define ptr @get_runtime_member(ptr %0, i64 %1)
// LLVM-NEXT: %3 = getelementptr i8, ptr %0, i64 %1
// LLVM-NEXT: ret ptr %3
// LLVM: define ptr @get_runtime_member(ptr %[[ARG0:.+]], i64 %[[ARG1:.+]])
// LLVM-NEXT: %[[#VAL:]] = getelementptr i8, ptr %[[ARG0]], i64 %[[ARG1]]
// LLVM-NEXT: ret ptr %[[#VAL]]
// LLVM-NEXT: }
}

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