39ec9de7c2
`sret` arguments are always going to reside in the stack/`alloca` address space, which makes the current formulation where their AS is derived from the pointee somewhat quaint. This patch ensures that `sret` ends up pointing to the `alloca` AS in IR function signatures, and also guards agains trying to pass a casted `alloca`d pointer to a `sret` arg, which can happen for most languages, when compiled for targets that have a non-zero `alloca` AS (e.g. AMDGCN) / map `LangAS::default` to a non-zero value (SPIR-V). A target could still choose to do something different here, by e.g. overriding `classifyReturnType` behaviour. In a broader sense, this patch extends non-aliased indirect args to also carry an AS, which leads to changing the `getIndirect()` interface. At the moment we're only using this for (indirect) returns, but it allows for future handling of indirect args themselves. We default to using the AllocaAS as that matches what Clang is currently doing, however if, in the future, a target would opt for e.g. placing indirect returns in some other storage, with another AS, this will require revisiting. --------- Co-authored-by: Matt Arsenault <arsenm2@gmail.com> Co-authored-by: Matt Arsenault <Matthew.Arsenault@amd.com>
105 lines
3.5 KiB
C++
105 lines
3.5 KiB
C++
//===- BPF.cpp ------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "ABIInfoImpl.h"
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#include "TargetInfo.h"
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using namespace clang;
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using namespace clang::CodeGen;
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//===----------------------------------------------------------------------===//
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// BPF ABI Implementation
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//===----------------------------------------------------------------------===//
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namespace {
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class BPFABIInfo : public DefaultABIInfo {
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public:
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BPFABIInfo(CodeGenTypes &CGT) : DefaultABIInfo(CGT) {}
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ABIArgInfo classifyArgumentType(QualType Ty) const {
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Ty = useFirstFieldIfTransparentUnion(Ty);
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if (isAggregateTypeForABI(Ty)) {
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uint64_t Bits = getContext().getTypeSize(Ty);
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if (Bits == 0)
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return ABIArgInfo::getIgnore();
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// If the aggregate needs 1 or 2 registers, do not use reference.
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if (Bits <= 128) {
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llvm::Type *CoerceTy;
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if (Bits <= 64) {
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CoerceTy =
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llvm::IntegerType::get(getVMContext(), llvm::alignTo(Bits, 8));
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} else {
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llvm::Type *RegTy = llvm::IntegerType::get(getVMContext(), 64);
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CoerceTy = llvm::ArrayType::get(RegTy, 2);
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}
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return ABIArgInfo::getDirect(CoerceTy);
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} else {
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return getNaturalAlignIndirect(Ty,
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getDataLayout().getAllocaAddrSpace());
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}
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}
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if (const EnumType *EnumTy = Ty->getAs<EnumType>())
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Ty = EnumTy->getDecl()->getIntegerType();
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ASTContext &Context = getContext();
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if (const auto *EIT = Ty->getAs<BitIntType>())
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if (EIT->getNumBits() > Context.getTypeSize(Context.Int128Ty))
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return getNaturalAlignIndirect(Ty,
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getDataLayout().getAllocaAddrSpace());
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return (isPromotableIntegerTypeForABI(Ty) ? ABIArgInfo::getExtend(Ty)
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: ABIArgInfo::getDirect());
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}
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ABIArgInfo classifyReturnType(QualType RetTy) const {
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if (RetTy->isVoidType())
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return ABIArgInfo::getIgnore();
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if (isAggregateTypeForABI(RetTy))
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return getNaturalAlignIndirect(RetTy,
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getDataLayout().getAllocaAddrSpace());
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// Treat an enum type as its underlying type.
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if (const EnumType *EnumTy = RetTy->getAs<EnumType>())
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RetTy = EnumTy->getDecl()->getIntegerType();
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ASTContext &Context = getContext();
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if (const auto *EIT = RetTy->getAs<BitIntType>())
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if (EIT->getNumBits() > Context.getTypeSize(Context.Int128Ty))
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return getNaturalAlignIndirect(RetTy,
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getDataLayout().getAllocaAddrSpace());
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// Caller will do necessary sign/zero extension.
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return ABIArgInfo::getDirect();
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}
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void computeInfo(CGFunctionInfo &FI) const override {
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FI.getReturnInfo() = classifyReturnType(FI.getReturnType());
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for (auto &I : FI.arguments())
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I.info = classifyArgumentType(I.type);
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}
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};
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class BPFTargetCodeGenInfo : public TargetCodeGenInfo {
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public:
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BPFTargetCodeGenInfo(CodeGenTypes &CGT)
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: TargetCodeGenInfo(std::make_unique<BPFABIInfo>(CGT)) {}
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};
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}
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std::unique_ptr<TargetCodeGenInfo>
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CodeGen::createBPFTargetCodeGenInfo(CodeGenModule &CGM) {
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return std::make_unique<BPFTargetCodeGenInfo>(CGM.getTypes());
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}
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