fe6fb910df
clang -fexperimental-relative-c++-abi-vtables might generate `@plt` and
`@gotpcrel` specifiers in data directives. The syntax is not used in
humand-written assembly code, and is not supported by GNU assembler.
Note: the `@plt` in `.word foo@plt` is different from
the legacy `call func@plt` (where `@plt` is simply ignored).
The `@plt` syntax was selected was simply due to a quirk of AsmParser:
the syntax was supported by all targets until I updated it
to be an opt-in feature in a0671758eb
RISC-V favors the `%specifier(expr)` syntax following MIPS and Sparc,
and we should follow this convention.
This PR adds support for `.word %pltpcrel(foo+offset)` and
`.word %gotpcrel(foo)`, and drops `@plt` and `@gotpcrel`.
* MCValue::SymA can no longer have a SymbolVariant. Add an assert
similar to that of AArch64ELFObjectWriter.cpp before
https://reviews.llvm.org/D81446 (see my analysis at
https://maskray.me/blog/2025-03-16-relocation-generation-in-assemblers
if intrigued)
* `jump foo@plt, x31` now has a different diagnostic.
Pull Request: https://github.com/llvm/llvm-project/pull/132569
64 lines
2.3 KiB
C++
64 lines
2.3 KiB
C++
//===-- RISCVTargetObjectFile.h - RISC-V Object Info ------------*- C++ -*-===//
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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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#ifndef LLVM_LIB_TARGET_RISCV_RISCVTARGETOBJECTFILE_H
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#define LLVM_LIB_TARGET_RISCV_RISCVTARGETOBJECTFILE_H
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#include "llvm/CodeGen/TargetLoweringObjectFileImpl.h"
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namespace llvm {
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/// This implementation is used for RISC-V ELF targets.
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class RISCVELFTargetObjectFile : public TargetLoweringObjectFileELF {
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MCSection *SmallDataSection;
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MCSection *SmallRODataSection;
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MCSection *SmallROData4Section;
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MCSection *SmallROData8Section;
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MCSection *SmallROData16Section;
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MCSection *SmallROData32Section;
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MCSection *SmallBSSSection;
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unsigned SSThreshold = 0;
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public:
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unsigned getTextSectionAlignment() const override;
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void Initialize(MCContext &Ctx, const TargetMachine &TM) override;
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/// Return true if this global address should be placed into small data/bss
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/// section.
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bool isGlobalInSmallSection(const GlobalObject *GO,
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const TargetMachine &TM) const;
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MCSection *SelectSectionForGlobal(const GlobalObject *GO, SectionKind Kind,
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const TargetMachine &TM) const override;
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/// Return true if this constant should be placed into small data section.
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bool isConstantInSmallSection(const DataLayout &DL, const Constant *CN) const;
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MCSection *getSectionForConstant(const DataLayout &DL, SectionKind Kind,
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const Constant *C,
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Align &Alignment) const override;
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void getModuleMetadata(Module &M) override;
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bool isInSmallSection(uint64_t Size) const;
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const MCExpr *createTargetMCExpr(const MCExpr *Expr,
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uint8_t Specifier) const override;
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const MCExpr *getIndirectSymViaGOTPCRel(const GlobalValue *GV,
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const MCSymbol *Sym,
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const MCValue &MV, int64_t Offset,
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MachineModuleInfo *MMI,
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MCStreamer &Streamer) const override;
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};
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} // end namespace llvm
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#endif
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