1 //===- lib/MC/MCWasmStreamer.cpp - Wasm Object Output ---------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file assembles .s files and emits Wasm .o object files.
12 //===----------------------------------------------------------------------===//
14 #include "llvm/MC/MCWasmStreamer.h"
15 #include "llvm/ADT/STLExtras.h"
16 #include "llvm/ADT/SmallPtrSet.h"
17 #include "llvm/MC/MCAsmBackend.h"
18 #include "llvm/MC/MCAsmInfo.h"
19 #include "llvm/MC/MCAsmLayout.h"
20 #include "llvm/MC/MCAssembler.h"
21 #include "llvm/MC/MCCodeEmitter.h"
22 #include "llvm/MC/MCContext.h"
23 #include "llvm/MC/MCExpr.h"
24 #include "llvm/MC/MCInst.h"
25 #include "llvm/MC/MCObjectFileInfo.h"
26 #include "llvm/MC/MCObjectStreamer.h"
27 #include "llvm/MC/MCObjectWriter.h"
28 #include "llvm/MC/MCSection.h"
29 #include "llvm/MC/MCSectionWasm.h"
30 #include "llvm/MC/MCSymbol.h"
31 #include "llvm/MC/MCSymbolWasm.h"
32 #include "llvm/MC/MCValue.h"
33 #include "llvm/Support/Casting.h"
34 #include "llvm/Support/Debug.h"
35 #include "llvm/Support/ErrorHandling.h"
36 #include "llvm/Support/TargetRegistry.h"
37 #include "llvm/Support/raw_ostream.h"
41 MCWasmStreamer::~MCWasmStreamer() {}
43 void MCWasmStreamer::mergeFragment(MCDataFragment *DF, MCDataFragment *EF) {
44 flushPendingLabels(DF, DF->getContents().size());
46 for (unsigned i = 0, e = EF->getFixups().size(); i != e; ++i) {
47 EF->getFixups()[i].setOffset(EF->getFixups()[i].getOffset() +
48 DF->getContents().size());
49 DF->getFixups().push_back(EF->getFixups()[i]);
51 DF->setHasInstructions(true);
52 DF->getContents().append(EF->getContents().begin(), EF->getContents().end());
55 void MCWasmStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) {
56 // Let the target do whatever target specific stuff it needs to do.
57 getAssembler().getBackend().handleAssemblerFlag(Flag);
59 // Do any generic stuff we need to do.
60 llvm_unreachable("invalid assembler flag!");
63 void MCWasmStreamer::ChangeSection(MCSection *Section,
64 const MCExpr *Subsection) {
65 MCAssembler &Asm = getAssembler();
66 auto *SectionWasm = static_cast<const MCSectionWasm *>(Section);
67 const MCSymbol *Grp = SectionWasm->getGroup();
69 Asm.registerSymbol(*Grp);
71 this->MCObjectStreamer::ChangeSection(Section, Subsection);
74 void MCWasmStreamer::EmitWeakReference(MCSymbol *Alias,
75 const MCSymbol *Symbol) {
76 getAssembler().registerSymbol(*Symbol);
77 const MCExpr *Value = MCSymbolRefExpr::create(
78 Symbol, MCSymbolRefExpr::VK_WEAKREF, getContext());
79 Alias->setVariableValue(Value);
82 bool MCWasmStreamer::EmitSymbolAttribute(MCSymbol *S, MCSymbolAttr Attribute) {
83 assert(Attribute != MCSA_IndirectSymbol && "indirect symbols not supported");
85 auto *Symbol = cast<MCSymbolWasm>(S);
87 // Adding a symbol attribute always introduces the symbol, note that an
88 // important side effect of calling registerSymbol here is to register
89 // the symbol with the assembler.
90 getAssembler().registerSymbol(*Symbol);
93 case MCSA_LazyReference:
95 case MCSA_SymbolResolver:
96 case MCSA_PrivateExtern:
97 case MCSA_WeakDefinition:
98 case MCSA_WeakDefAutoPrivate:
100 case MCSA_IndirectSymbol:
105 case MCSA_WeakReference:
106 Symbol->setWeak(true);
107 Symbol->setExternal(true);
111 Symbol->setExternal(true);
114 case MCSA_ELF_TypeFunction:
115 Symbol->setIsFunction(true);
118 case MCSA_ELF_TypeObject:
119 Symbol->setIsFunction(false);
123 // unrecognized directive
124 llvm_unreachable("unexpected MCSymbolAttr");
131 void MCWasmStreamer::EmitCommonSymbol(MCSymbol *S, uint64_t Size,
132 unsigned ByteAlignment) {
133 llvm_unreachable("Common symbols are not yet implemented for Wasm");
136 void MCWasmStreamer::emitELFSize(MCSymbol *Symbol, const MCExpr *Value) {
137 cast<MCSymbolWasm>(Symbol)->setSize(Value);
140 void MCWasmStreamer::EmitLocalCommonSymbol(MCSymbol *S, uint64_t Size,
141 unsigned ByteAlignment) {
142 llvm_unreachable("Local common symbols are not yet implemented for Wasm");
145 void MCWasmStreamer::EmitValueImpl(const MCExpr *Value, unsigned Size,
147 MCObjectStreamer::EmitValueImpl(Value, Size, Loc);
150 void MCWasmStreamer::EmitValueToAlignment(unsigned ByteAlignment, int64_t Value,
152 unsigned MaxBytesToEmit) {
153 MCObjectStreamer::EmitValueToAlignment(ByteAlignment, Value, ValueSize,
157 void MCWasmStreamer::EmitIdent(StringRef IdentString) {
158 MCSection *Comment = getAssembler().getContext().getWasmSection(
161 SwitchSection(Comment);
166 EmitBytes(IdentString);
171 void MCWasmStreamer::EmitInstToFragment(const MCInst &Inst,
172 const MCSubtargetInfo &STI) {
173 this->MCObjectStreamer::EmitInstToFragment(Inst, STI);
176 void MCWasmStreamer::EmitInstToData(const MCInst &Inst,
177 const MCSubtargetInfo &STI) {
178 MCAssembler &Assembler = getAssembler();
179 SmallVector<MCFixup, 4> Fixups;
180 SmallString<256> Code;
181 raw_svector_ostream VecOS(Code);
182 Assembler.getEmitter().encodeInstruction(Inst, VecOS, Fixups, STI);
184 // Append the encoded instruction to the current data fragment (or create a
185 // new such fragment if the current fragment is not a data fragment).
186 MCDataFragment *DF = getOrCreateDataFragment();
188 // Add the fixups and data.
189 for (unsigned i = 0, e = Fixups.size(); i != e; ++i) {
190 Fixups[i].setOffset(Fixups[i].getOffset() + DF->getContents().size());
191 DF->getFixups().push_back(Fixups[i]);
193 DF->setHasInstructions(true);
194 DF->getContents().append(Code.begin(), Code.end());
197 void MCWasmStreamer::FinishImpl() {
200 this->MCObjectStreamer::FinishImpl();
203 MCStreamer *llvm::createWasmStreamer(MCContext &Context, MCAsmBackend &MAB,
204 raw_pwrite_stream &OS, MCCodeEmitter *CE,
206 MCWasmStreamer *S = new MCWasmStreamer(Context, MAB, OS, CE);
208 S->getAssembler().setRelaxAll(true);
212 void MCWasmStreamer::EmitThumbFunc(MCSymbol *Func) {
213 llvm_unreachable("Generic Wasm doesn't support this directive");
216 void MCWasmStreamer::EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {
217 llvm_unreachable("Wasm doesn't support this directive");
220 void MCWasmStreamer::EmitZerofill(MCSection *Section, MCSymbol *Symbol,
221 uint64_t Size, unsigned ByteAlignment) {
222 llvm_unreachable("Wasm doesn't support this directive");
225 void MCWasmStreamer::EmitTBSSSymbol(MCSection *Section, MCSymbol *Symbol,
226 uint64_t Size, unsigned ByteAlignment) {
227 llvm_unreachable("Wasm doesn't support this directive");