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//===- lib/MC/MCWasmStreamer.cpp - Wasm Object Output ---------------------===//
//
// 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 assembles .s files and emits Wasm .o object files.
//
//===----------------------------------------------------------------------===//
#include "llvm/MC/MCWasmStreamer.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/MC/MCAsmBackend.h"
#include "llvm/MC/MCAsmLayout.h"
#include "llvm/MC/MCAssembler.h"
#include "llvm/MC/MCCodeEmitter.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCInst.h"
#include "llvm/MC/MCObjectStreamer.h"
#include "llvm/MC/MCSection.h"
#include "llvm/MC/MCSectionWasm.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/MC/MCSymbolWasm.h"
#include "llvm/MC/MCValue.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
MCWasmStreamer::~MCWasmStreamer() = default; // anchor.
void MCWasmStreamer::mergeFragment(MCDataFragment *DF, MCDataFragment *EF) {
flushPendingLabels(DF, DF->getContents().size());
for (unsigned I = 0, E = EF->getFixups().size(); I != E; ++I) {
EF->getFixups()[I].setOffset(EF->getFixups()[I].getOffset() +
DF->getContents().size());
DF->getFixups().push_back(EF->getFixups()[I]);
}
if (DF->getSubtargetInfo() == nullptr && EF->getSubtargetInfo())
DF->setHasInstructions(*EF->getSubtargetInfo());
DF->getContents().append(EF->getContents().begin(), EF->getContents().end());
}
void MCWasmStreamer::emitAssemblerFlag(MCAssemblerFlag Flag) {
// Let the target do whatever target specific stuff it needs to do.
getAssembler().getBackend().handleAssemblerFlag(Flag);
// Do any generic stuff we need to do.
llvm_unreachable("invalid assembler flag!");
}
void MCWasmStreamer::changeSection(MCSection *Section,
const MCExpr *Subsection) {
MCAssembler &Asm = getAssembler();
auto *SectionWasm = cast<MCSectionWasm>(Section);
const MCSymbol *Grp = SectionWasm->getGroup();
if (Grp)
Asm.registerSymbol(*Grp);
this->MCObjectStreamer::changeSection(Section, Subsection);
Asm.registerSymbol(*Section->getBeginSymbol());
}
void MCWasmStreamer::emitWeakReference(MCSymbol *Alias,
const MCSymbol *Symbol) {
getAssembler().registerSymbol(*Symbol);
const MCExpr *Value = MCSymbolRefExpr::create(
Symbol, MCSymbolRefExpr::VK_WEAKREF, getContext());
Alias->setVariableValue(Value);
}
bool MCWasmStreamer::emitSymbolAttribute(MCSymbol *S, MCSymbolAttr Attribute) {
assert(Attribute != MCSA_IndirectSymbol && "indirect symbols not supported");
auto *Symbol = cast<MCSymbolWasm>(S);
// Adding a symbol attribute always introduces the symbol; note that an
// important side effect of calling registerSymbol here is to register the
// symbol with the assembler.
getAssembler().registerSymbol(*Symbol);
switch (Attribute) {
case MCSA_LazyReference:
case MCSA_Reference:
case MCSA_SymbolResolver:
case MCSA_PrivateExtern:
case MCSA_WeakDefinition:
case MCSA_WeakDefAutoPrivate:
case MCSA_Invalid:
case MCSA_IndirectSymbol:
case MCSA_Protected:
return false;
case MCSA_Hidden:
Symbol->setHidden(true);
break;
case MCSA_Weak:
case MCSA_WeakReference:
Symbol->setWeak(true);
Symbol->setExternal(true);
break;
case MCSA_Global:
Symbol->setExternal(true);
break;
case MCSA_ELF_TypeFunction:
Symbol->setType(wasm::WASM_SYMBOL_TYPE_FUNCTION);
break;
case MCSA_ELF_TypeObject:
case MCSA_Cold:
break;
case MCSA_NoDeadStrip:
Symbol->setNoStrip();
break;
default:
// unrecognized directive
llvm_unreachable("unexpected MCSymbolAttr");
return false;
}
return true;
}
void MCWasmStreamer::emitCommonSymbol(MCSymbol *S, uint64_t Size,
unsigned ByteAlignment) {
llvm_unreachable("Common symbols are not yet implemented for Wasm");
}
void MCWasmStreamer::emitELFSize(MCSymbol *Symbol, const MCExpr *Value) {
cast<MCSymbolWasm>(Symbol)->setSize(Value);
}
void MCWasmStreamer::emitLocalCommonSymbol(MCSymbol *S, uint64_t Size,
unsigned ByteAlignment) {
llvm_unreachable("Local common symbols are not yet implemented for Wasm");
}
void MCWasmStreamer::emitIdent(StringRef IdentString) {
// TODO(sbc): Add the ident section once we support mergable strings
// sections in the object format
}
void MCWasmStreamer::emitInstToFragment(const MCInst &Inst,
const MCSubtargetInfo &STI) {
this->MCObjectStreamer::emitInstToFragment(Inst, STI);
}
void MCWasmStreamer::emitInstToData(const MCInst &Inst,
const MCSubtargetInfo &STI) {
MCAssembler &Assembler = getAssembler();
SmallVector<MCFixup, 4> Fixups;
SmallString<256> Code;
raw_svector_ostream VecOS(Code);
Assembler.getEmitter().encodeInstruction(Inst, VecOS, Fixups, STI);
// Append the encoded instruction to the current data fragment (or create a
// new such fragment if the current fragment is not a data fragment).
MCDataFragment *DF = getOrCreateDataFragment();
// Add the fixups and data.
for (unsigned I = 0, E = Fixups.size(); I != E; ++I) {
Fixups[I].setOffset(Fixups[I].getOffset() + DF->getContents().size());
DF->getFixups().push_back(Fixups[I]);
}
DF->setHasInstructions(STI);
DF->getContents().append(Code.begin(), Code.end());
}
void MCWasmStreamer::finishImpl() {
emitFrames(nullptr);
this->MCObjectStreamer::finishImpl();
}
MCStreamer *llvm::createWasmStreamer(MCContext &Context,
std::unique_ptr<MCAsmBackend> &&MAB,
std::unique_ptr<MCObjectWriter> &&OW,
std::unique_ptr<MCCodeEmitter> &&CE,
bool RelaxAll) {
MCWasmStreamer *S =
new MCWasmStreamer(Context, std::move(MAB), std::move(OW), std::move(CE));
if (RelaxAll)
S->getAssembler().setRelaxAll(true);
return S;
}
void MCWasmStreamer::emitThumbFunc(MCSymbol *Func) {
llvm_unreachable("Generic Wasm doesn't support this directive");
}
void MCWasmStreamer::emitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {
llvm_unreachable("Wasm doesn't support this directive");
}
void MCWasmStreamer::emitZerofill(MCSection *Section, MCSymbol *Symbol,
uint64_t Size, unsigned ByteAlignment,
SMLoc Loc) {
llvm_unreachable("Wasm doesn't support this directive");
}
void MCWasmStreamer::emitTBSSSymbol(MCSection *Section, MCSymbol *Symbol,
uint64_t Size, unsigned ByteAlignment) {
llvm_unreachable("Wasm doesn't support this directive");
}
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