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/MCObjectStreamer.h"
17 #include "llvm/MC/MCContext.h"
18 #include "llvm/MC/MCSection.h"
19 #include "llvm/MC/MCSymbol.h"
20 #include "llvm/MC/MCExpr.h"
21 #include "llvm/MC/MCValue.h"
22 #include "llvm/MC/MCAssembler.h"
23 #include "llvm/MC/MCAsmLayout.h"
24 #include "llvm/MC/MCCodeEmitter.h"
25 #include "llvm/MC/MCSectionCOFF.h"
26 #include "llvm/Target/TargetRegistry.h"
27 #include "llvm/Target/TargetAsmBackend.h"
28 #include "llvm/ADT/StringMap.h"
30 #include "llvm/Support/COFF.h"
31 #include "llvm/Support/Debug.h"
32 #include "llvm/Support/ErrorHandling.h"
33 #include "llvm/Support/raw_ostream.h"
37 class WinCOFFStreamer : public MCObjectStreamer {
39 MCSymbol const *CurSymbol;
41 WinCOFFStreamer(MCContext &Context,
42 TargetAsmBackend &TAB,
46 void AddCommonSymbol(MCSymbol *Symbol, uint64_t Size,
47 unsigned ByteAlignment, bool External);
49 // MCStreamer interface
51 virtual void InitSections();
52 virtual void EmitLabel(MCSymbol *Symbol);
53 virtual void EmitAssemblerFlag(MCAssemblerFlag Flag);
54 virtual void EmitAssignment(MCSymbol *Symbol, const MCExpr *Value);
55 virtual void EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute);
56 virtual void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue);
57 virtual void BeginCOFFSymbolDef(MCSymbol const *Symbol);
58 virtual void EmitCOFFSymbolStorageClass(int StorageClass);
59 virtual void EmitCOFFSymbolType(int Type);
60 virtual void EndCOFFSymbolDef();
61 virtual void EmitELFSize(MCSymbol *Symbol, const MCExpr *Value);
62 virtual void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
63 unsigned ByteAlignment);
64 virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size);
65 virtual void EmitZerofill(const MCSection *Section, MCSymbol *Symbol,
66 unsigned Size,unsigned ByteAlignment);
67 virtual void EmitTBSSSymbol(const MCSection *Section, MCSymbol *Symbol,
68 uint64_t Size, unsigned ByteAlignment);
69 virtual void EmitBytes(StringRef Data, unsigned AddrSpace);
70 virtual void EmitValue(const MCExpr *Value, unsigned Size,
72 virtual void EmitGPRel32Value(const MCExpr *Value);
73 virtual void EmitValueToAlignment(unsigned ByteAlignment, int64_t Value,
74 unsigned ValueSize, unsigned MaxBytesToEmit);
75 virtual void EmitCodeAlignment(unsigned ByteAlignment,
76 unsigned MaxBytesToEmit);
77 virtual void EmitValueToOffset(const MCExpr *Offset, unsigned char Value);
78 virtual void EmitFileDirective(StringRef Filename);
79 virtual void EmitDwarfFileDirective(unsigned FileNo,StringRef Filename);
80 virtual void EmitInstruction(const MCInst &Instruction);
81 virtual void Finish();
84 void SetSection(StringRef Section,
85 unsigned Characteristics,
87 SwitchSection(getContext().getCOFFSection(Section, Characteristics, Kind));
90 void SetSectionText() {
92 COFF::IMAGE_SCN_CNT_CODE
93 | COFF::IMAGE_SCN_MEM_EXECUTE
94 | COFF::IMAGE_SCN_MEM_READ,
95 SectionKind::getText());
96 EmitCodeAlignment(4, 0);
99 void SetSectionData() {
101 COFF::IMAGE_SCN_CNT_INITIALIZED_DATA
102 | COFF::IMAGE_SCN_MEM_READ
103 | COFF::IMAGE_SCN_MEM_WRITE,
104 SectionKind::getDataRel());
105 EmitCodeAlignment(4, 0);
108 void SetSectionBSS() {
110 COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA
111 | COFF::IMAGE_SCN_MEM_READ
112 | COFF::IMAGE_SCN_MEM_WRITE,
113 SectionKind::getBSS());
114 EmitCodeAlignment(4, 0);
118 } // end anonymous namespace.
120 WinCOFFStreamer::WinCOFFStreamer(MCContext &Context,
121 TargetAsmBackend &TAB,
124 : MCObjectStreamer(Context, TAB, OS, &CE, true)
128 void WinCOFFStreamer::AddCommonSymbol(MCSymbol *Symbol, uint64_t Size,
129 unsigned ByteAlignment, bool External) {
130 assert(!Symbol->isInSection() && "Symbol must not already have a section!");
132 std::string SectionName(".bss$linkonce");
133 SectionName.append(Symbol->getName().begin(), Symbol->getName().end());
135 MCSymbolData &SymbolData = getAssembler().getOrCreateSymbolData(*Symbol);
137 unsigned Characteristics =
138 COFF::IMAGE_SCN_LNK_COMDAT |
139 COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA |
140 COFF::IMAGE_SCN_MEM_READ |
141 COFF::IMAGE_SCN_MEM_WRITE;
143 int Selection = COFF::IMAGE_COMDAT_SELECT_LARGEST;
145 const MCSection *Section = MCStreamer::getContext().getCOFFSection(
146 SectionName, Characteristics, Selection, SectionKind::getBSS());
148 MCSectionData &SectionData = getAssembler().getOrCreateSectionData(*Section);
150 if (SectionData.getAlignment() < ByteAlignment)
151 SectionData.setAlignment(ByteAlignment);
153 SymbolData.setExternal(External);
155 Symbol->setSection(*Section);
157 if (ByteAlignment != 1)
158 new MCAlignFragment(ByteAlignment, 0, 0, ByteAlignment, &SectionData);
160 SymbolData.setFragment(new MCFillFragment(0, 0, Size, &SectionData));
163 // MCStreamer interface
165 void WinCOFFStreamer::InitSections() {
172 void WinCOFFStreamer::EmitLabel(MCSymbol *Symbol) {
173 // TODO: This is copied almost exactly from the MachOStreamer. Consider
174 // merging into MCObjectStreamer?
175 assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
176 assert(!Symbol->isVariable() && "Cannot emit a variable symbol!");
177 assert(CurSection && "Cannot emit before setting section!");
179 Symbol->setSection(*CurSection);
181 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
183 // FIXME: This is wasteful, we don't necessarily need to create a data
184 // fragment. Instead, we should mark the symbol as pointing into the data
185 // fragment if it exists, otherwise we should just queue the label and set its
186 // fragment pointer when we emit the next fragment.
187 MCDataFragment *DF = getOrCreateDataFragment();
189 assert(!SD.getFragment() && "Unexpected fragment on symbol data!");
191 SD.setOffset(DF->getContents().size());
194 void WinCOFFStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) {
195 llvm_unreachable("not implemented");
198 void WinCOFFStreamer::EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) {
199 assert((Symbol->isInSection()
200 ? Symbol->getSection().getVariant() == MCSection::SV_COFF
201 : true) && "Got non COFF section in the COFF backend!");
202 // FIXME: This is all very ugly and depressing. What needs to happen here
203 // depends on quite a few things that are all part of relaxation, which we
204 // don't really even do.
206 if (Value->getKind() != MCExpr::SymbolRef) {
207 // TODO: This is exactly the same as MachOStreamer. Consider merging into
209 getAssembler().getOrCreateSymbolData(*Symbol);
210 AddValueSymbols(Value);
211 Symbol->setVariableValue(Value);
213 // FIXME: This is a horrible way to do this :(. This should really be
214 // handled after we are done with the MC* objects and immediately before
215 // writing out the object file when we know exactly what the symbol should
216 // look like in the coff symbol table. I'm not doing that now because the
217 // COFF object writer doesn't have a clearly defined separation between MC
218 // data structures, the object writers data structures, and the raw, POD,
219 // data structures that get written to disk.
221 // Copy over the aliased data.
222 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
223 const MCSymbolData &RealSD = getAssembler().getOrCreateSymbolData(
224 dyn_cast<const MCSymbolRefExpr>(Value)->getSymbol());
226 // FIXME: This is particularly nasty because it breaks as soon as any data
227 // members of MCSymbolData change.
228 SD.CommonAlign = RealSD.CommonAlign;
229 SD.CommonSize = RealSD.CommonSize;
230 SD.Flags = RealSD.Flags;
231 SD.Fragment = RealSD.Fragment;
232 SD.Index = RealSD.Index;
233 SD.IsExternal = RealSD.IsExternal;
234 SD.IsPrivateExtern = RealSD.IsPrivateExtern;
235 SD.Offset = RealSD.Offset;
236 SD.SymbolSize = RealSD.SymbolSize;
240 void WinCOFFStreamer::EmitSymbolAttribute(MCSymbol *Symbol,
241 MCSymbolAttr Attribute) {
242 assert(Symbol && "Symbol must be non-null!");
243 assert((Symbol->isInSection()
244 ? Symbol->getSection().getVariant() == MCSection::SV_COFF
245 : true) && "Got non COFF section in the COFF backend!");
247 case MCSA_WeakReference:
249 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
250 SD.modifyFlags(COFF::SF_WeakExternal, COFF::SF_WeakExternal);
251 SD.setExternal(true);
256 getAssembler().getOrCreateSymbolData(*Symbol).setExternal(true);
260 llvm_unreachable("unsupported attribute");
265 void WinCOFFStreamer::EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {
266 llvm_unreachable("not implemented");
269 void WinCOFFStreamer::BeginCOFFSymbolDef(MCSymbol const *Symbol) {
270 assert((Symbol->isInSection()
271 ? Symbol->getSection().getVariant() == MCSection::SV_COFF
272 : true) && "Got non COFF section in the COFF backend!");
273 assert(CurSymbol == NULL && "EndCOFFSymbolDef must be called between calls "
274 "to BeginCOFFSymbolDef!");
278 void WinCOFFStreamer::EmitCOFFSymbolStorageClass(int StorageClass) {
279 assert(CurSymbol != NULL && "BeginCOFFSymbolDef must be called first!");
280 assert((StorageClass & ~0xFF) == 0 && "StorageClass must only have data in "
283 getAssembler().getOrCreateSymbolData(*CurSymbol).modifyFlags(
284 StorageClass << COFF::SF_ClassShift,
288 void WinCOFFStreamer::EmitCOFFSymbolType(int Type) {
289 assert(CurSymbol != NULL && "BeginCOFFSymbolDef must be called first!");
290 assert((Type & ~0xFFFF) == 0 && "Type must only have data in the first 2 "
293 getAssembler().getOrCreateSymbolData(*CurSymbol).modifyFlags(
294 Type << COFF::SF_TypeShift,
298 void WinCOFFStreamer::EndCOFFSymbolDef() {
299 assert(CurSymbol != NULL && "BeginCOFFSymbolDef must be called first!");
303 void WinCOFFStreamer::EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) {
304 llvm_unreachable("not implemented");
307 void WinCOFFStreamer::EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
308 unsigned ByteAlignment) {
309 assert((Symbol->isInSection()
310 ? Symbol->getSection().getVariant() == MCSection::SV_COFF
311 : true) && "Got non COFF section in the COFF backend!");
312 AddCommonSymbol(Symbol, Size, ByteAlignment, true);
315 void WinCOFFStreamer::EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size) {
316 assert((Symbol->isInSection()
317 ? Symbol->getSection().getVariant() == MCSection::SV_COFF
318 : true) && "Got non COFF section in the COFF backend!");
319 AddCommonSymbol(Symbol, Size, 1, false);
322 void WinCOFFStreamer::EmitZerofill(const MCSection *Section, MCSymbol *Symbol,
323 unsigned Size,unsigned ByteAlignment) {
324 llvm_unreachable("not implemented");
327 void WinCOFFStreamer::EmitTBSSSymbol(const MCSection *Section, MCSymbol *Symbol,
328 uint64_t Size, unsigned ByteAlignment) {
329 llvm_unreachable("not implemented");
332 void WinCOFFStreamer::EmitBytes(StringRef Data, unsigned AddrSpace) {
333 // TODO: This is copied exactly from the MachOStreamer. Consider merging into
335 getOrCreateDataFragment()->getContents().append(Data.begin(), Data.end());
338 void WinCOFFStreamer::EmitValue(const MCExpr *Value, unsigned Size,
339 unsigned AddrSpace) {
340 assert(AddrSpace == 0 && "Address space must be 0!");
342 // TODO: This is copied exactly from the MachOStreamer. Consider merging into
344 MCDataFragment *DF = getOrCreateDataFragment();
346 // Avoid fixups when possible.
348 if (AddValueSymbols(Value)->EvaluateAsAbsolute(AbsValue)) {
349 // FIXME: Endianness assumption.
350 for (unsigned i = 0; i != Size; ++i)
351 DF->getContents().push_back(uint8_t(AbsValue >> (i * 8)));
353 DF->addFixup(MCFixup::Create(DF->getContents().size(),
354 AddValueSymbols(Value),
355 MCFixup::getKindForSize(Size)));
356 DF->getContents().resize(DF->getContents().size() + Size, 0);
360 void WinCOFFStreamer::EmitGPRel32Value(const MCExpr *Value) {
361 llvm_unreachable("not implemented");
364 void WinCOFFStreamer::EmitValueToAlignment(unsigned ByteAlignment,
367 unsigned MaxBytesToEmit) {
368 // TODO: This is copied exactly from the MachOStreamer. Consider merging into
370 if (MaxBytesToEmit == 0)
371 MaxBytesToEmit = ByteAlignment;
372 new MCAlignFragment(ByteAlignment, Value, ValueSize, MaxBytesToEmit,
373 getCurrentSectionData());
375 // Update the maximum alignment on the current section if necessary.
376 if (ByteAlignment > getCurrentSectionData()->getAlignment())
377 getCurrentSectionData()->setAlignment(ByteAlignment);
380 void WinCOFFStreamer::EmitCodeAlignment(unsigned ByteAlignment,
381 unsigned MaxBytesToEmit) {
382 // TODO: This is copied exactly from the MachOStreamer. Consider merging into
384 if (MaxBytesToEmit == 0)
385 MaxBytesToEmit = ByteAlignment;
386 MCAlignFragment *F = new MCAlignFragment(ByteAlignment, 0, 1, MaxBytesToEmit,
387 getCurrentSectionData());
388 F->setEmitNops(true);
390 // Update the maximum alignment on the current section if necessary.
391 if (ByteAlignment > getCurrentSectionData()->getAlignment())
392 getCurrentSectionData()->setAlignment(ByteAlignment);
395 void WinCOFFStreamer::EmitValueToOffset(const MCExpr *Offset,
396 unsigned char Value) {
397 llvm_unreachable("not implemented");
400 void WinCOFFStreamer::EmitFileDirective(StringRef Filename) {
401 // Ignore for now, linkers don't care, and proper debug
402 // info will be a much large effort.
405 void WinCOFFStreamer::EmitDwarfFileDirective(unsigned FileNo,
406 StringRef Filename) {
407 llvm_unreachable("not implemented");
410 void WinCOFFStreamer::EmitInstruction(const MCInst &Instruction) {
411 for (unsigned i = 0, e = Instruction.getNumOperands(); i != e; ++i)
412 if (Instruction.getOperand(i).isExpr())
413 AddValueSymbols(Instruction.getOperand(i).getExpr());
415 getCurrentSectionData()->setHasInstructions(true);
417 MCInstFragment *Fragment =
418 new MCInstFragment(Instruction, getCurrentSectionData());
420 raw_svector_ostream VecOS(Fragment->getCode());
422 getAssembler().getEmitter().EncodeInstruction(Instruction, VecOS,
423 Fragment->getFixups());
426 void WinCOFFStreamer::Finish() {
427 MCObjectStreamer::Finish();
432 MCStreamer *createWinCOFFStreamer(MCContext &Context,
433 TargetAsmBackend &TAB,
437 WinCOFFStreamer *S = new WinCOFFStreamer(Context, TAB, CE, OS);
438 S->getAssembler().setRelaxAll(RelaxAll);