1 //===-- llvm/MC/WinCOFFStreamer.cpp -----------------------------*- C++ -*-===//
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 contains an implementation of a Win32 COFF object file streamer.
12 //===----------------------------------------------------------------------===//
14 #define DEBUG_TYPE "WinCOFFStreamer"
16 #include "llvm/MC/MCStreamer.h"
17 #include "llvm/MC/MCAsmBackend.h"
18 #include "llvm/MC/MCAsmLayout.h"
19 #include "llvm/MC/MCAssembler.h"
20 #include "llvm/MC/MCCodeEmitter.h"
21 #include "llvm/MC/MCContext.h"
22 #include "llvm/MC/MCExpr.h"
23 #include "llvm/MC/MCObjectFileInfo.h"
24 #include "llvm/MC/MCObjectStreamer.h"
25 #include "llvm/MC/MCSection.h"
26 #include "llvm/MC/MCSectionCOFF.h"
27 #include "llvm/MC/MCSymbol.h"
28 #include "llvm/MC/MCValue.h"
29 #include "llvm/MC/MCWin64EH.h"
30 #include "llvm/Support/COFF.h"
31 #include "llvm/Support/Debug.h"
32 #include "llvm/Support/ErrorHandling.h"
33 #include "llvm/Support/TargetRegistry.h"
34 #include "llvm/Support/raw_ostream.h"
39 class WinCOFFStreamer : public MCObjectStreamer {
41 MCSymbol const *CurSymbol;
43 WinCOFFStreamer(MCContext &Context,
48 // MCStreamer interface
50 void InitSections() override;
51 void EmitLabel(MCSymbol *Symbol) override;
52 void EmitDebugLabel(MCSymbol *Symbol) override;
53 void EmitAssemblerFlag(MCAssemblerFlag Flag) override;
54 void EmitThumbFunc(MCSymbol *Func) override;
55 bool EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute) override;
56 void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) override;
57 void BeginCOFFSymbolDef(MCSymbol const *Symbol) override;
58 void EmitCOFFSymbolStorageClass(int StorageClass) override;
59 void EmitCOFFSymbolType(int Type) override;
60 void EndCOFFSymbolDef() override;
61 void EmitCOFFSectionIndex(MCSymbol const *Symbol) override;
62 void EmitCOFFSecRel32(MCSymbol const *Symbol) override;
63 void EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) override;
64 void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
65 unsigned ByteAlignment) override;
66 void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
67 unsigned ByteAlignment) override;
68 void EmitZerofill(const MCSection *Section, MCSymbol *Symbol,
69 uint64_t Size,unsigned ByteAlignment) override;
70 void EmitTBSSSymbol(const MCSection *Section, MCSymbol *Symbol,
71 uint64_t Size, unsigned ByteAlignment) override;
72 void EmitFileDirective(StringRef Filename) override;
73 void EmitIdent(StringRef IdentString) override;
74 void EmitWin64EHHandlerData() override;
75 void FinishImpl() override;
78 void EmitInstToData(const MCInst &Inst, const MCSubtargetInfo &STI) override {
79 MCDataFragment *DF = getOrCreateDataFragment();
81 SmallVector<MCFixup, 4> Fixups;
82 SmallString<256> Code;
83 raw_svector_ostream VecOS(Code);
84 getAssembler().getEmitter().EncodeInstruction(Inst, VecOS, Fixups, STI);
87 // Add the fixups and data.
88 for (unsigned i = 0, e = Fixups.size(); i != e; ++i) {
89 Fixups[i].setOffset(Fixups[i].getOffset() + DF->getContents().size());
90 DF->getFixups().push_back(Fixups[i]);
92 DF->getContents().append(Code.begin(), Code.end());
95 } // end anonymous namespace.
97 WinCOFFStreamer::WinCOFFStreamer(MCContext &Context, MCAsmBackend &MAB,
98 MCCodeEmitter &CE, raw_ostream &OS)
99 : MCObjectStreamer(Context, MAB, OS, &CE), CurSymbol(nullptr) {}
101 // MCStreamer interface
103 void WinCOFFStreamer::InitSections() {
104 // FIXME: this is identical to the ELF one.
105 // This emulates the same behavior of GNU as. This makes it easier
106 // to compare the output as the major sections are in the same order.
107 SwitchSection(getContext().getObjectFileInfo()->getTextSection());
108 EmitCodeAlignment(4);
110 SwitchSection(getContext().getObjectFileInfo()->getDataSection());
111 EmitCodeAlignment(4);
113 SwitchSection(getContext().getObjectFileInfo()->getBSSSection());
114 EmitCodeAlignment(4);
116 SwitchSection(getContext().getObjectFileInfo()->getTextSection());
119 void WinCOFFStreamer::EmitLabel(MCSymbol *Symbol) {
120 assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
121 MCObjectStreamer::EmitLabel(Symbol);
124 void WinCOFFStreamer::EmitDebugLabel(MCSymbol *Symbol) {
127 void WinCOFFStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) {
128 llvm_unreachable("not implemented");
131 void WinCOFFStreamer::EmitThumbFunc(MCSymbol *Func) {
132 llvm_unreachable("not implemented");
135 bool WinCOFFStreamer::EmitSymbolAttribute(MCSymbol *Symbol,
136 MCSymbolAttr Attribute) {
137 assert(Symbol && "Symbol must be non-null!");
138 assert((Symbol->isInSection()
139 ? Symbol->getSection().getVariant() == MCSection::SV_COFF
140 : true) && "Got non-COFF section in the COFF backend!");
142 case MCSA_WeakReference:
144 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
145 SD.modifyFlags(COFF::SF_WeakExternal, COFF::SF_WeakExternal);
146 SD.setExternal(true);
151 getAssembler().getOrCreateSymbolData(*Symbol).setExternal(true);
161 void WinCOFFStreamer::EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {
162 llvm_unreachable("not implemented");
165 void WinCOFFStreamer::BeginCOFFSymbolDef(MCSymbol const *Symbol) {
166 assert((Symbol->isInSection()
167 ? Symbol->getSection().getVariant() == MCSection::SV_COFF
168 : true) && "Got non-COFF section in the COFF backend!");
169 assert(!CurSymbol && "EndCOFFSymbolDef must be called between calls "
170 "to BeginCOFFSymbolDef!");
174 void WinCOFFStreamer::EmitCOFFSymbolStorageClass(int StorageClass) {
175 assert(CurSymbol && "BeginCOFFSymbolDef must be called first!");
176 assert((StorageClass & ~0xFF) == 0 && "StorageClass must only have data in "
179 getAssembler().getOrCreateSymbolData(*CurSymbol).modifyFlags(
180 StorageClass << COFF::SF_ClassShift,
184 void WinCOFFStreamer::EmitCOFFSymbolType(int Type) {
185 assert(CurSymbol && "BeginCOFFSymbolDef must be called first!");
186 assert((Type & ~0xFFFF) == 0 && "Type must only have data in the first 2 "
189 getAssembler().getOrCreateSymbolData(*CurSymbol).modifyFlags(
190 Type << COFF::SF_TypeShift,
194 void WinCOFFStreamer::EndCOFFSymbolDef() {
195 assert(CurSymbol && "BeginCOFFSymbolDef must be called first!");
199 void WinCOFFStreamer::EmitCOFFSectionIndex(MCSymbol const *Symbol) {
200 MCDataFragment *DF = getOrCreateDataFragment();
201 DF->getFixups().push_back(MCFixup::Create(
202 DF->getContents().size(), MCSymbolRefExpr::Create(Symbol, getContext()),
204 DF->getContents().resize(DF->getContents().size() + 4, 0);
207 void WinCOFFStreamer::EmitCOFFSecRel32(MCSymbol const *Symbol) {
208 MCDataFragment *DF = getOrCreateDataFragment();
209 DF->getFixups().push_back(MCFixup::Create(
210 DF->getContents().size(), MCSymbolRefExpr::Create(Symbol, getContext()),
212 DF->getContents().resize(DF->getContents().size() + 4, 0);
215 void WinCOFFStreamer::EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) {
216 llvm_unreachable("not implemented");
219 void WinCOFFStreamer::EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
220 unsigned ByteAlignment) {
221 assert((Symbol->isInSection()
222 ? Symbol->getSection().getVariant() == MCSection::SV_COFF
223 : true) && "Got non-COFF section in the COFF backend!");
225 if (ByteAlignment > 32)
227 "The linker won't align common symbols beyond 32 bytes.");
229 AssignSection(Symbol, nullptr);
231 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
232 SD.setExternal(true);
233 SD.setCommon(Size, ByteAlignment);
236 void WinCOFFStreamer::EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
237 unsigned ByteAlignment) {
238 assert(!Symbol->isInSection() && "Symbol must not already have a section!");
240 const MCSection *Section = getContext().getObjectFileInfo()->getBSSSection();
241 MCSectionData &SectionData = getAssembler().getOrCreateSectionData(*Section);
242 if (SectionData.getAlignment() < ByteAlignment)
243 SectionData.setAlignment(ByteAlignment);
245 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
246 SD.setExternal(false);
248 AssignSection(Symbol, Section);
250 if (ByteAlignment != 1)
251 new MCAlignFragment(ByteAlignment, /*_Value=*/0, /*_ValueSize=*/0,
252 ByteAlignment, &SectionData);
255 new MCFillFragment(/*_Value=*/0, /*_ValueSize=*/0, Size, &SectionData));
258 void WinCOFFStreamer::EmitZerofill(const MCSection *Section, MCSymbol *Symbol,
259 uint64_t Size,unsigned ByteAlignment) {
260 llvm_unreachable("not implemented");
263 void WinCOFFStreamer::EmitTBSSSymbol(const MCSection *Section, MCSymbol *Symbol,
264 uint64_t Size, unsigned ByteAlignment) {
265 llvm_unreachable("not implemented");
268 void WinCOFFStreamer::EmitFileDirective(StringRef Filename) {
269 getAssembler().addFileName(Filename);
272 // TODO: Implement this if you want to emit .comment section in COFF obj files.
273 void WinCOFFStreamer::EmitIdent(StringRef IdentString) {
274 llvm_unreachable("unsupported directive");
277 void WinCOFFStreamer::EmitWin64EHHandlerData() {
278 MCStreamer::EmitWin64EHHandlerData();
280 // We have to emit the unwind info now, because this directive
281 // actually switches to the .xdata section!
282 MCWin64EHUnwindEmitter::EmitUnwindInfo(*this, getCurrentW64UnwindInfo());
285 void WinCOFFStreamer::FinishImpl() {
286 EmitFrames(nullptr, true);
288 MCObjectStreamer::FinishImpl();
293 MCStreamer *createWinCOFFStreamer(MCContext &Context,
298 WinCOFFStreamer *S = new WinCOFFStreamer(Context, MAB, CE, OS);
299 S->getAssembler().setRelaxAll(RelaxAll);