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//===-- RISCVELFStreamer.cpp - RISCV 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 RISCV specific target streamer methods.
//
//===----------------------------------------------------------------------===//
#include "RISCVELFStreamer.h"
#include "MCTargetDesc/RISCVAsmBackend.h"
#include "RISCVMCTargetDesc.h"
#include "Utils/RISCVBaseInfo.h"
#include "llvm/BinaryFormat/ELF.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCSectionELF.h"
#include "llvm/MC/MCSubtargetInfo.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());
RISCVABI::ABI ABI = MAB.getTargetABI();
assert(ABI != RISCVABI::ABI_Unknown && "Improperly initialised target ABI");
unsigned EFlags = MCA.getELFHeaderEFlags();
if (Features[RISCV::FeatureStdExtC])
EFlags |= ELF::EF_RISCV_RVC;
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:
EFlags |= ELF::EF_RISCV_RVE;
break;
case RISCVABI::ABI_Unknown:
llvm_unreachable("Improperly initialised target ABI");
}
MCA.setELFHeaderEFlags(EFlags);
}
MCELFStreamer &RISCVTargetELFStreamer::getStreamer() {
return static_cast<MCELFStreamer &>(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) {
setAttributeItem(Attribute, Value, /*OverwriteExisting=*/true);
}
void RISCVTargetELFStreamer::emitTextAttribute(unsigned Attribute,
StringRef String) {
setAttributeItem(Attribute, String, /*OverwriteExisting=*/true);
}
void RISCVTargetELFStreamer::emitIntTextAttribute(unsigned Attribute,
unsigned IntValue,
StringRef StringValue) {
setAttributeItems(Attribute, IntValue, StringValue,
/*OverwriteExisting=*/true);
}
void RISCVTargetELFStreamer::finishAttributeSection() {
if (Contents.empty())
return;
if (AttributeSection) {
Streamer.SwitchSection(AttributeSection);
} else {
MCAssembler &MCA = getStreamer().getAssembler();
AttributeSection = MCA.getContext().getELFSection(
".riscv.attributes", ELF::SHT_RISCV_ATTRIBUTES, 0);
Streamer.SwitchSection(AttributeSection);
Streamer.emitInt8(ELFAttrs::Format_Version);
}
// Vendor size + Vendor name + '\0'
const size_t VendorHeaderSize = 4 + CurrentVendor.size() + 1;
// Tag + Tag Size
const size_t TagHeaderSize = 1 + 4;
const size_t ContentsSize = calculateContentSize();
Streamer.emitInt32(VendorHeaderSize + TagHeaderSize + ContentsSize);
Streamer.emitBytes(CurrentVendor);
Streamer.emitInt8(0); // '\0'
Streamer.emitInt8(ELFAttrs::File);
Streamer.emitInt32(TagHeaderSize + ContentsSize);
// Size should have been accounted for already, now
// emit each field as its type (ULEB or String).
for (AttributeItem item : Contents) {
Streamer.emitULEB128IntValue(item.Tag);
switch (item.Type) {
default:
llvm_unreachable("Invalid attribute type");
case AttributeType::Numeric:
Streamer.emitULEB128IntValue(item.IntValue);
break;
case AttributeType::Text:
Streamer.emitBytes(item.StringValue);
Streamer.emitInt8(0); // '\0'
break;
case AttributeType::NumericAndText:
Streamer.emitULEB128IntValue(item.IntValue);
Streamer.emitBytes(item.StringValue);
Streamer.emitInt8(0); // '\0'
break;
}
}
Contents.clear();
}
size_t RISCVTargetELFStreamer::calculateContentSize() const {
size_t Result = 0;
for (AttributeItem item : Contents) {
switch (item.Type) {
case AttributeType::Hidden:
break;
case AttributeType::Numeric:
Result += getULEB128Size(item.Tag);
Result += getULEB128Size(item.IntValue);
break;
case AttributeType::Text:
Result += getULEB128Size(item.Tag);
Result += item.StringValue.size() + 1; // string + '\0'
break;
case AttributeType::NumericAndText:
Result += getULEB128Size(item.Tag);
Result += getULEB128Size(item.IntValue);
Result += item.StringValue.size() + 1; // string + '\0';
break;
}
}
return Result;
}
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