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//===-- RISCVELFStreamer.cpp - RISC-V ELF Target Streamer Methods ---------===//
//
// 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 provides RISC-V specific target streamer methods.
//
//===----------------------------------------------------------------------===//
#include "RISCVELFStreamer.h"
#include "RISCVAsmBackend.h"
#include "RISCVBaseInfo.h"
#include "RISCVMCTargetDesc.h"
#include "llvm/BinaryFormat/ELF.h"
#include "llvm/MC/MCAsmBackend.h"
#include "llvm/MC/MCAssembler.h"
#include "llvm/MC/MCCodeEmitter.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCObjectWriter.h"
#include "llvm/MC/MCSectionELF.h"
#include "llvm/MC/MCSubtargetInfo.h"
#include "llvm/MC/MCValue.h"
#include "llvm/Support/LEB128.h"
#include "llvm/Support/RISCVAttributes.h"
using namespace llvm;
// This part is for ELF object output.
RISCVTargetELFStreamer::RISCVTargetELFStreamer(MCStreamer &S,
const MCSubtargetInfo &STI)
: RISCVTargetStreamer(S), CurrentVendor("riscv") {
MCAssembler &MCA = getStreamer().getAssembler();
const FeatureBitset &Features = STI.getFeatureBits();
auto &MAB = static_cast<RISCVAsmBackend &>(MCA.getBackend());
setTargetABI(RISCVABI::computeTargetABI(STI.getTargetTriple(), Features,
MAB.getTargetOptions().getABIName()));
setFlagsFromFeatures(STI);
// `j label` in `.option norelax; j label; .option relax; ...; label:` needs a
// relocation to ensure the jump target is correct after linking. This is due
// to a limitation that shouldForceRelocation has to make the decision upfront
// without knowing a possibly future .option relax. When RISCVAsmParser is used,
// its ParseInstruction may call setForceRelocs as well.
if (STI.hasFeature(RISCV::FeatureRelax))
static_cast<RISCVAsmBackend &>(MAB).setForceRelocs();
}
RISCVELFStreamer &RISCVTargetELFStreamer::getStreamer() {
return static_cast<RISCVELFStreamer &>(Streamer);
}
void RISCVTargetELFStreamer::emitDirectiveOptionPush() {}
void RISCVTargetELFStreamer::emitDirectiveOptionPop() {}
void RISCVTargetELFStreamer::emitDirectiveOptionPIC() {}
void RISCVTargetELFStreamer::emitDirectiveOptionNoPIC() {}
void RISCVTargetELFStreamer::emitDirectiveOptionRVC() {}
void RISCVTargetELFStreamer::emitDirectiveOptionNoRVC() {}
void RISCVTargetELFStreamer::emitDirectiveOptionRelax() {}
void RISCVTargetELFStreamer::emitDirectiveOptionNoRelax() {}
void RISCVTargetELFStreamer::emitAttribute(unsigned Attribute, unsigned Value) {
getStreamer().setAttributeItem(Attribute, Value, /*OverwriteExisting=*/true);
}
void RISCVTargetELFStreamer::emitTextAttribute(unsigned Attribute,
StringRef String) {
getStreamer().setAttributeItem(Attribute, String, /*OverwriteExisting=*/true);
}
void RISCVTargetELFStreamer::emitIntTextAttribute(unsigned Attribute,
unsigned IntValue,
StringRef StringValue) {
getStreamer().setAttributeItems(Attribute, IntValue, StringValue,
/*OverwriteExisting=*/true);
}
void RISCVTargetELFStreamer::finishAttributeSection() {
RISCVELFStreamer &S = getStreamer();
if (S.Contents.empty())
return;
S.emitAttributesSection(CurrentVendor, ".riscv.attributes",
ELF::SHT_RISCV_ATTRIBUTES, AttributeSection);
}
void RISCVTargetELFStreamer::finish() {
RISCVTargetStreamer::finish();
MCAssembler &MCA = getStreamer().getAssembler();
RISCVABI::ABI ABI = getTargetABI();
unsigned EFlags = MCA.getELFHeaderEFlags();
if (hasRVC())
EFlags |= ELF::EF_RISCV_RVC;
if (hasTSO())
EFlags |= ELF::EF_RISCV_TSO;
switch (ABI) {
case RISCVABI::ABI_ILP32:
case RISCVABI::ABI_LP64:
break;
case RISCVABI::ABI_ILP32F:
case RISCVABI::ABI_LP64F:
EFlags |= ELF::EF_RISCV_FLOAT_ABI_SINGLE;
break;
case RISCVABI::ABI_ILP32D:
case RISCVABI::ABI_LP64D:
EFlags |= ELF::EF_RISCV_FLOAT_ABI_DOUBLE;
break;
case RISCVABI::ABI_ILP32E:
case RISCVABI::ABI_LP64E:
EFlags |= ELF::EF_RISCV_RVE;
break;
case RISCVABI::ABI_Unknown:
llvm_unreachable("Improperly initialised target ABI");
}
MCA.setELFHeaderEFlags(EFlags);
}
void RISCVTargetELFStreamer::reset() {
AttributeSection = nullptr;
}
void RISCVTargetELFStreamer::emitDirectiveVariantCC(MCSymbol &Symbol) {
getStreamer().getAssembler().registerSymbol(Symbol);
cast<MCSymbolELF>(Symbol).setOther(ELF::STO_RISCV_VARIANT_CC);
}
void RISCVELFStreamer::reset() {
static_cast<RISCVTargetStreamer *>(getTargetStreamer())->reset();
MCELFStreamer::reset();
MappingSymbolCounter = 0;
LastMappingSymbols.clear();
LastEMS = EMS_None;
}
void RISCVELFStreamer::emitDataMappingSymbol() {
if (LastEMS == EMS_Data)
return;
emitMappingSymbol("$d");
LastEMS = EMS_Data;
}
void RISCVELFStreamer::emitInstructionsMappingSymbol() {
if (LastEMS == EMS_Instructions)
return;
emitMappingSymbol("$x");
LastEMS = EMS_Instructions;
}
void RISCVELFStreamer::emitMappingSymbol(StringRef Name) {
auto *Symbol = cast<MCSymbolELF>(getContext().getOrCreateSymbol(
Name + "." + Twine(MappingSymbolCounter++)));
emitLabel(Symbol);
Symbol->setType(ELF::STT_NOTYPE);
Symbol->setBinding(ELF::STB_LOCAL);
}
void RISCVELFStreamer::changeSection(MCSection *Section,
const MCExpr *Subsection) {
// We have to keep track of the mapping symbol state of any sections we
// use. Each one should start off as EMS_None, which is provided as the
// default constructor by DenseMap::lookup.
LastMappingSymbols[getPreviousSection().first] = LastEMS;
LastEMS = LastMappingSymbols.lookup(Section);
MCELFStreamer::changeSection(Section, Subsection);
}
void RISCVELFStreamer::emitInstruction(const MCInst &Inst,
const MCSubtargetInfo &STI) {
emitInstructionsMappingSymbol();
MCELFStreamer::emitInstruction(Inst, STI);
}
void RISCVELFStreamer::emitBytes(StringRef Data) {
emitDataMappingSymbol();
MCELFStreamer::emitBytes(Data);
}
void RISCVELFStreamer::emitFill(const MCExpr &NumBytes, uint64_t FillValue,
SMLoc Loc) {
emitDataMappingSymbol();
MCELFStreamer::emitFill(NumBytes, FillValue, Loc);
}
void RISCVELFStreamer::emitValueImpl(const MCExpr *Value, unsigned Size,
SMLoc Loc) {
emitDataMappingSymbol();
MCELFStreamer::emitValueImpl(Value, Size, Loc);
}
namespace llvm {
MCELFStreamer *createRISCVELFStreamer(MCContext &C,
std::unique_ptr<MCAsmBackend> MAB,
std::unique_ptr<MCObjectWriter> MOW,
std::unique_ptr<MCCodeEmitter> MCE,
bool RelaxAll) {
RISCVELFStreamer *S =
new RISCVELFStreamer(C, std::move(MAB), std::move(MOW), std::move(MCE));
S->getAssembler().setRelaxAll(RelaxAll);
return S;
}
} // namespace llvm
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