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 EmitThumbFunc(MCSymbol *Func);
55 virtual void EmitAssignment(MCSymbol *Symbol, const MCExpr *Value);
56 virtual void EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute);
57 virtual void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue);
58 virtual void BeginCOFFSymbolDef(MCSymbol const *Symbol);
59 virtual void EmitCOFFSymbolStorageClass(int StorageClass);
60 virtual void EmitCOFFSymbolType(int Type);
61 virtual void EndCOFFSymbolDef();
62 virtual void EmitELFSize(MCSymbol *Symbol, const MCExpr *Value);
63 virtual void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
64 unsigned ByteAlignment);
65 virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size);
66 virtual void EmitZerofill(const MCSection *Section, MCSymbol *Symbol,
67 unsigned Size,unsigned ByteAlignment);
68 virtual void EmitTBSSSymbol(const MCSection *Section, MCSymbol *Symbol,
69 uint64_t Size, unsigned ByteAlignment);
70 virtual void EmitBytes(StringRef Data, unsigned AddrSpace);
71 virtual void EmitValue(const MCExpr *Value, unsigned Size,
73 virtual void EmitGPRel32Value(const MCExpr *Value);
74 virtual void EmitValueToAlignment(unsigned ByteAlignment, int64_t Value,
75 unsigned ValueSize, unsigned MaxBytesToEmit);
76 virtual void EmitCodeAlignment(unsigned ByteAlignment,
77 unsigned MaxBytesToEmit);
78 virtual void EmitValueToOffset(const MCExpr *Offset, unsigned char Value);
79 virtual void EmitFileDirective(StringRef Filename);
80 virtual void EmitInstruction(const MCInst &Instruction);
81 virtual void Finish();
84 virtual void EmitInstToFragment(const MCInst &Inst) {
85 llvm_unreachable("Not used by WinCOFF.");
87 virtual void EmitInstToData(const MCInst &Inst) {
88 llvm_unreachable("Not used by WinCOFF.");
91 void SetSection(StringRef Section,
92 unsigned Characteristics,
94 SwitchSection(getContext().getCOFFSection(Section, Characteristics, Kind));
97 void SetSectionText() {
99 COFF::IMAGE_SCN_CNT_CODE
100 | COFF::IMAGE_SCN_MEM_EXECUTE
101 | COFF::IMAGE_SCN_MEM_READ,
102 SectionKind::getText());
103 EmitCodeAlignment(4, 0);
106 void SetSectionData() {
108 COFF::IMAGE_SCN_CNT_INITIALIZED_DATA
109 | COFF::IMAGE_SCN_MEM_READ
110 | COFF::IMAGE_SCN_MEM_WRITE,
111 SectionKind::getDataRel());
112 EmitCodeAlignment(4, 0);
115 void SetSectionBSS() {
117 COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA
118 | COFF::IMAGE_SCN_MEM_READ
119 | COFF::IMAGE_SCN_MEM_WRITE,
120 SectionKind::getBSS());
121 EmitCodeAlignment(4, 0);
125 } // end anonymous namespace.
127 WinCOFFStreamer::WinCOFFStreamer(MCContext &Context,
128 TargetAsmBackend &TAB,
131 : MCObjectStreamer(Context, TAB, OS, &CE, true)
135 void WinCOFFStreamer::AddCommonSymbol(MCSymbol *Symbol, uint64_t Size,
136 unsigned ByteAlignment, bool External) {
137 assert(!Symbol->isInSection() && "Symbol must not already have a section!");
139 std::string SectionName(".bss$linkonce");
140 SectionName.append(Symbol->getName().begin(), Symbol->getName().end());
142 MCSymbolData &SymbolData = getAssembler().getOrCreateSymbolData(*Symbol);
144 unsigned Characteristics =
145 COFF::IMAGE_SCN_LNK_COMDAT |
146 COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA |
147 COFF::IMAGE_SCN_MEM_READ |
148 COFF::IMAGE_SCN_MEM_WRITE;
150 int Selection = COFF::IMAGE_COMDAT_SELECT_LARGEST;
152 const MCSection *Section = MCStreamer::getContext().getCOFFSection(
153 SectionName, Characteristics, Selection, SectionKind::getBSS());
155 MCSectionData &SectionData = getAssembler().getOrCreateSectionData(*Section);
157 if (SectionData.getAlignment() < ByteAlignment)
158 SectionData.setAlignment(ByteAlignment);
160 SymbolData.setExternal(External);
162 Symbol->setSection(*Section);
164 if (ByteAlignment != 1)
165 new MCAlignFragment(ByteAlignment, 0, 0, ByteAlignment, &SectionData);
167 SymbolData.setFragment(new MCFillFragment(0, 0, Size, &SectionData));
170 // MCStreamer interface
172 void WinCOFFStreamer::InitSections() {
179 void WinCOFFStreamer::EmitLabel(MCSymbol *Symbol) {
180 // TODO: This is copied almost exactly from the MachOStreamer. Consider
181 // merging into MCObjectStreamer?
182 assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
183 assert(!Symbol->isVariable() && "Cannot emit a variable symbol!");
184 assert(CurSection && "Cannot emit before setting section!");
186 Symbol->setSection(*CurSection);
188 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
190 // FIXME: This is wasteful, we don't necessarily need to create a data
191 // fragment. Instead, we should mark the symbol as pointing into the data
192 // fragment if it exists, otherwise we should just queue the label and set its
193 // fragment pointer when we emit the next fragment.
194 MCDataFragment *DF = getOrCreateDataFragment();
196 assert(!SD.getFragment() && "Unexpected fragment on symbol data!");
198 SD.setOffset(DF->getContents().size());
201 void WinCOFFStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) {
202 llvm_unreachable("not implemented");
205 void WinCOFFStreamer::EmitThumbFunc(MCSymbol *Func) {
206 llvm_unreachable("not implemented");
209 void WinCOFFStreamer::EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) {
210 assert((Symbol->isInSection()
211 ? Symbol->getSection().getVariant() == MCSection::SV_COFF
212 : true) && "Got non COFF section in the COFF backend!");
213 // FIXME: This is all very ugly and depressing. What needs to happen here
214 // depends on quite a few things that are all part of relaxation, which we
215 // don't really even do.
217 if (Value->getKind() != MCExpr::SymbolRef) {
218 // TODO: This is exactly the same as MachOStreamer. Consider merging into
220 getAssembler().getOrCreateSymbolData(*Symbol);
221 AddValueSymbols(Value);
222 Symbol->setVariableValue(Value);
224 // FIXME: This is a horrible way to do this :(. This should really be
225 // handled after we are done with the MC* objects and immediately before
226 // writing out the object file when we know exactly what the symbol should
227 // look like in the coff symbol table. I'm not doing that now because the
228 // COFF object writer doesn't have a clearly defined separation between MC
229 // data structures, the object writers data structures, and the raw, POD,
230 // data structures that get written to disk.
232 // Copy over the aliased data.
233 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
234 const MCSymbolData &RealSD = getAssembler().getOrCreateSymbolData(
235 dyn_cast<const MCSymbolRefExpr>(Value)->getSymbol());
237 // FIXME: This is particularly nasty because it breaks as soon as any data
238 // members of MCSymbolData change.
239 SD.CommonAlign = RealSD.CommonAlign;
240 SD.CommonSize = RealSD.CommonSize;
241 SD.Flags = RealSD.Flags;
242 SD.Fragment = RealSD.Fragment;
243 SD.Index = RealSD.Index;
244 SD.IsExternal = RealSD.IsExternal;
245 SD.IsPrivateExtern = RealSD.IsPrivateExtern;
246 SD.Offset = RealSD.Offset;
247 SD.SymbolSize = RealSD.SymbolSize;
251 void WinCOFFStreamer::EmitSymbolAttribute(MCSymbol *Symbol,
252 MCSymbolAttr Attribute) {
253 assert(Symbol && "Symbol must be non-null!");
254 assert((Symbol->isInSection()
255 ? Symbol->getSection().getVariant() == MCSection::SV_COFF
256 : true) && "Got non COFF section in the COFF backend!");
258 case MCSA_WeakReference:
260 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
261 SD.modifyFlags(COFF::SF_WeakExternal, COFF::SF_WeakExternal);
262 SD.setExternal(true);
267 getAssembler().getOrCreateSymbolData(*Symbol).setExternal(true);
271 llvm_unreachable("unsupported attribute");
276 void WinCOFFStreamer::EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {
277 llvm_unreachable("not implemented");
280 void WinCOFFStreamer::BeginCOFFSymbolDef(MCSymbol const *Symbol) {
281 assert((Symbol->isInSection()
282 ? Symbol->getSection().getVariant() == MCSection::SV_COFF
283 : true) && "Got non COFF section in the COFF backend!");
284 assert(CurSymbol == NULL && "EndCOFFSymbolDef must be called between calls "
285 "to BeginCOFFSymbolDef!");
289 void WinCOFFStreamer::EmitCOFFSymbolStorageClass(int StorageClass) {
290 assert(CurSymbol != NULL && "BeginCOFFSymbolDef must be called first!");
291 assert((StorageClass & ~0xFF) == 0 && "StorageClass must only have data in "
294 getAssembler().getOrCreateSymbolData(*CurSymbol).modifyFlags(
295 StorageClass << COFF::SF_ClassShift,
299 void WinCOFFStreamer::EmitCOFFSymbolType(int Type) {
300 assert(CurSymbol != NULL && "BeginCOFFSymbolDef must be called first!");
301 assert((Type & ~0xFFFF) == 0 && "Type must only have data in the first 2 "
304 getAssembler().getOrCreateSymbolData(*CurSymbol).modifyFlags(
305 Type << COFF::SF_TypeShift,
309 void WinCOFFStreamer::EndCOFFSymbolDef() {
310 assert(CurSymbol != NULL && "BeginCOFFSymbolDef must be called first!");
314 void WinCOFFStreamer::EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) {
315 llvm_unreachable("not implemented");
318 void WinCOFFStreamer::EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
319 unsigned ByteAlignment) {
320 assert((Symbol->isInSection()
321 ? Symbol->getSection().getVariant() == MCSection::SV_COFF
322 : true) && "Got non COFF section in the COFF backend!");
323 AddCommonSymbol(Symbol, Size, ByteAlignment, true);
326 void WinCOFFStreamer::EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size) {
327 assert((Symbol->isInSection()
328 ? Symbol->getSection().getVariant() == MCSection::SV_COFF
329 : true) && "Got non COFF section in the COFF backend!");
330 AddCommonSymbol(Symbol, Size, 1, false);
333 void WinCOFFStreamer::EmitZerofill(const MCSection *Section, MCSymbol *Symbol,
334 unsigned Size,unsigned ByteAlignment) {
335 llvm_unreachable("not implemented");
338 void WinCOFFStreamer::EmitTBSSSymbol(const MCSection *Section, MCSymbol *Symbol,
339 uint64_t Size, unsigned ByteAlignment) {
340 llvm_unreachable("not implemented");
343 void WinCOFFStreamer::EmitBytes(StringRef Data, unsigned AddrSpace) {
344 // TODO: This is copied exactly from the MachOStreamer. Consider merging into
346 getOrCreateDataFragment()->getContents().append(Data.begin(), Data.end());
349 void WinCOFFStreamer::EmitValue(const MCExpr *Value, unsigned Size,
350 unsigned AddrSpace) {
351 assert(AddrSpace == 0 && "Address space must be 0!");
353 // TODO: This is copied exactly from the MachOStreamer. Consider merging into
355 MCDataFragment *DF = getOrCreateDataFragment();
357 // Avoid fixups when possible.
359 if (AddValueSymbols(Value)->EvaluateAsAbsolute(AbsValue)) {
360 // FIXME: Endianness assumption.
361 for (unsigned i = 0; i != Size; ++i)
362 DF->getContents().push_back(uint8_t(AbsValue >> (i * 8)));
364 DF->addFixup(MCFixup::Create(DF->getContents().size(),
365 AddValueSymbols(Value),
366 MCFixup::getKindForSize(Size, false)));
367 DF->getContents().resize(DF->getContents().size() + Size, 0);
371 void WinCOFFStreamer::EmitGPRel32Value(const MCExpr *Value) {
372 llvm_unreachable("not implemented");
375 void WinCOFFStreamer::EmitValueToAlignment(unsigned ByteAlignment,
378 unsigned MaxBytesToEmit) {
379 // TODO: This is copied exactly from the MachOStreamer. Consider merging into
381 if (MaxBytesToEmit == 0)
382 MaxBytesToEmit = ByteAlignment;
383 new MCAlignFragment(ByteAlignment, Value, ValueSize, MaxBytesToEmit,
384 getCurrentSectionData());
386 // Update the maximum alignment on the current section if necessary.
387 if (ByteAlignment > getCurrentSectionData()->getAlignment())
388 getCurrentSectionData()->setAlignment(ByteAlignment);
391 void WinCOFFStreamer::EmitCodeAlignment(unsigned ByteAlignment,
392 unsigned MaxBytesToEmit) {
393 // TODO: This is copied exactly from the MachOStreamer. Consider merging into
395 if (MaxBytesToEmit == 0)
396 MaxBytesToEmit = ByteAlignment;
397 MCAlignFragment *F = new MCAlignFragment(ByteAlignment, 0, 1, MaxBytesToEmit,
398 getCurrentSectionData());
399 F->setEmitNops(true);
401 // Update the maximum alignment on the current section if necessary.
402 if (ByteAlignment > getCurrentSectionData()->getAlignment())
403 getCurrentSectionData()->setAlignment(ByteAlignment);
406 void WinCOFFStreamer::EmitValueToOffset(const MCExpr *Offset,
407 unsigned char Value) {
408 llvm_unreachable("not implemented");
411 void WinCOFFStreamer::EmitFileDirective(StringRef Filename) {
412 // Ignore for now, linkers don't care, and proper debug
413 // info will be a much large effort.
416 void WinCOFFStreamer::EmitInstruction(const MCInst &Instruction) {
417 for (unsigned i = 0, e = Instruction.getNumOperands(); i != e; ++i)
418 if (Instruction.getOperand(i).isExpr())
419 AddValueSymbols(Instruction.getOperand(i).getExpr());
421 getCurrentSectionData()->setHasInstructions(true);
423 MCInstFragment *Fragment =
424 new MCInstFragment(Instruction, getCurrentSectionData());
426 raw_svector_ostream VecOS(Fragment->getCode());
428 getAssembler().getEmitter().EncodeInstruction(Instruction, VecOS,
429 Fragment->getFixups());
432 void WinCOFFStreamer::Finish() {
433 MCObjectStreamer::Finish();
438 MCStreamer *createWinCOFFStreamer(MCContext &Context,
439 TargetAsmBackend &TAB,
443 WinCOFFStreamer *S = new WinCOFFStreamer(Context, TAB, CE, OS);
444 S->getAssembler().setRelaxAll(RelaxAll);