b205f2bb89
Currently, if target of s_branch instruction is in another section, it will fail with the error of undefined label. Although in this case, the label is not undefined but present in another section. This patch tries to handle this issue. So while handling fixup_si_sopp_br fixup in getRelocType, if the target label is undefined we issue an error as before. If it is defined, a new relocation type R_AMDGPU_REL16 is returned. This issue has been reported in https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100181 and https://bugs.llvm.org/show_bug.cgi?id=45887. Before https://reviews.llvm.org/D79943, we used to get an crash for this scenario. The crash is fixed now but the we still get an undefined label error. Jumps to other section can arise with hold/cold splitting. A patch to handle the relocation in lld will follow shortly. Reviewed By: arsenm Differential Revision: https://reviews.llvm.org/D105760
102 lines
3.4 KiB
C++
102 lines
3.4 KiB
C++
//===- AMDGPUELFObjectWriter.cpp - AMDGPU ELF Writer ----------------------===//
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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 "AMDGPUFixupKinds.h"
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#include "AMDGPUMCTargetDesc.h"
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#include "llvm/MC/MCContext.h"
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#include "llvm/MC/MCELFObjectWriter.h"
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#include "llvm/MC/MCValue.h"
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using namespace llvm;
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namespace {
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class AMDGPUELFObjectWriter : public MCELFObjectTargetWriter {
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public:
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AMDGPUELFObjectWriter(bool Is64Bit, uint8_t OSABI, bool HasRelocationAddend,
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uint8_t ABIVersion);
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protected:
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unsigned getRelocType(MCContext &Ctx, const MCValue &Target,
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const MCFixup &Fixup, bool IsPCRel) const override;
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};
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} // end anonymous namespace
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AMDGPUELFObjectWriter::AMDGPUELFObjectWriter(bool Is64Bit,
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uint8_t OSABI,
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bool HasRelocationAddend,
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uint8_t ABIVersion)
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: MCELFObjectTargetWriter(Is64Bit, OSABI, ELF::EM_AMDGPU,
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HasRelocationAddend, ABIVersion) {}
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unsigned AMDGPUELFObjectWriter::getRelocType(MCContext &Ctx,
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const MCValue &Target,
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const MCFixup &Fixup,
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bool IsPCRel) const {
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if (const auto *SymA = Target.getSymA()) {
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// SCRATCH_RSRC_DWORD[01] is a special global variable that represents
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// the scratch buffer.
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if (SymA->getSymbol().getName() == "SCRATCH_RSRC_DWORD0" ||
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SymA->getSymbol().getName() == "SCRATCH_RSRC_DWORD1")
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return ELF::R_AMDGPU_ABS32_LO;
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}
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switch (Target.getAccessVariant()) {
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default:
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break;
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case MCSymbolRefExpr::VK_GOTPCREL:
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return ELF::R_AMDGPU_GOTPCREL;
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case MCSymbolRefExpr::VK_AMDGPU_GOTPCREL32_LO:
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return ELF::R_AMDGPU_GOTPCREL32_LO;
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case MCSymbolRefExpr::VK_AMDGPU_GOTPCREL32_HI:
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return ELF::R_AMDGPU_GOTPCREL32_HI;
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case MCSymbolRefExpr::VK_AMDGPU_REL32_LO:
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return ELF::R_AMDGPU_REL32_LO;
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case MCSymbolRefExpr::VK_AMDGPU_REL32_HI:
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return ELF::R_AMDGPU_REL32_HI;
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case MCSymbolRefExpr::VK_AMDGPU_REL64:
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return ELF::R_AMDGPU_REL64;
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}
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switch (Fixup.getKind()) {
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default: break;
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case FK_PCRel_4:
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return ELF::R_AMDGPU_REL32;
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case FK_Data_4:
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case FK_SecRel_4:
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return ELF::R_AMDGPU_ABS32;
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case FK_Data_8:
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return ELF::R_AMDGPU_ABS64;
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}
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if (Fixup.getTargetKind() == AMDGPU::fixup_si_sopp_br) {
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const auto *SymA = Target.getSymA();
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assert(SymA);
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if (SymA->getSymbol().isUndefined()) {
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Ctx.reportError(Fixup.getLoc(), Twine("undefined label '") +
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SymA->getSymbol().getName() + "'");
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return ELF::R_AMDGPU_NONE;
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}
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return ELF::R_AMDGPU_REL16;
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}
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llvm_unreachable("unhandled relocation type");
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}
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std::unique_ptr<MCObjectTargetWriter>
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llvm::createAMDGPUELFObjectWriter(bool Is64Bit, uint8_t OSABI,
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bool HasRelocationAddend,
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uint8_t ABIVersion) {
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return std::make_unique<AMDGPUELFObjectWriter>(Is64Bit, OSABI,
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HasRelocationAddend,
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ABIVersion);
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}
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