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 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 EmitInstruction(const MCInst &Instruction);
80 virtual void Finish();
83 virtual void EmitInstToFragment(const MCInst &Inst) {
84 llvm_unreachable("Not used by WinCOFF.");
86 virtual void EmitInstToData(const MCInst &Inst) {
87 llvm_unreachable("Not used by WinCOFF.");
90 void SetSection(StringRef Section,
91 unsigned Characteristics,
93 SwitchSection(getContext().getCOFFSection(Section, Characteristics, Kind));
96 void SetSectionText() {
98 COFF::IMAGE_SCN_CNT_CODE
99 | COFF::IMAGE_SCN_MEM_EXECUTE
100 | COFF::IMAGE_SCN_MEM_READ,
101 SectionKind::getText());
102 EmitCodeAlignment(4, 0);
105 void SetSectionData() {
107 COFF::IMAGE_SCN_CNT_INITIALIZED_DATA
108 | COFF::IMAGE_SCN_MEM_READ
109 | COFF::IMAGE_SCN_MEM_WRITE,
110 SectionKind::getDataRel());
111 EmitCodeAlignment(4, 0);
114 void SetSectionBSS() {
116 COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA
117 | COFF::IMAGE_SCN_MEM_READ
118 | COFF::IMAGE_SCN_MEM_WRITE,
119 SectionKind::getBSS());
120 EmitCodeAlignment(4, 0);
124 } // end anonymous namespace.
126 WinCOFFStreamer::WinCOFFStreamer(MCContext &Context,
127 TargetAsmBackend &TAB,
130 : MCObjectStreamer(Context, TAB, OS, &CE, true)
134 void WinCOFFStreamer::AddCommonSymbol(MCSymbol *Symbol, uint64_t Size,
135 unsigned ByteAlignment, bool External) {
136 assert(!Symbol->isInSection() && "Symbol must not already have a section!");
138 std::string SectionName(".bss$linkonce");
139 SectionName.append(Symbol->getName().begin(), Symbol->getName().end());
141 MCSymbolData &SymbolData = getAssembler().getOrCreateSymbolData(*Symbol);
143 unsigned Characteristics =
144 COFF::IMAGE_SCN_LNK_COMDAT |
145 COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA |
146 COFF::IMAGE_SCN_MEM_READ |
147 COFF::IMAGE_SCN_MEM_WRITE;
149 int Selection = COFF::IMAGE_COMDAT_SELECT_LARGEST;
151 const MCSection *Section = MCStreamer::getContext().getCOFFSection(
152 SectionName, Characteristics, Selection, SectionKind::getBSS());
154 MCSectionData &SectionData = getAssembler().getOrCreateSectionData(*Section);
156 if (SectionData.getAlignment() < ByteAlignment)
157 SectionData.setAlignment(ByteAlignment);
159 SymbolData.setExternal(External);
161 Symbol->setSection(*Section);
163 if (ByteAlignment != 1)
164 new MCAlignFragment(ByteAlignment, 0, 0, ByteAlignment, &SectionData);
166 SymbolData.setFragment(new MCFillFragment(0, 0, Size, &SectionData));
169 // MCStreamer interface
171 void WinCOFFStreamer::InitSections() {
178 void WinCOFFStreamer::EmitLabel(MCSymbol *Symbol) {
179 // TODO: This is copied almost exactly from the MachOStreamer. Consider
180 // merging into MCObjectStreamer?
181 assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
182 assert(!Symbol->isVariable() && "Cannot emit a variable symbol!");
183 assert(CurSection && "Cannot emit before setting section!");
185 Symbol->setSection(*CurSection);
187 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
189 // FIXME: This is wasteful, we don't necessarily need to create a data
190 // fragment. Instead, we should mark the symbol as pointing into the data
191 // fragment if it exists, otherwise we should just queue the label and set its
192 // fragment pointer when we emit the next fragment.
193 MCDataFragment *DF = getOrCreateDataFragment();
195 assert(!SD.getFragment() && "Unexpected fragment on symbol data!");
197 SD.setOffset(DF->getContents().size());
200 void WinCOFFStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) {
201 llvm_unreachable("not implemented");
204 void WinCOFFStreamer::EmitThumbFunc(MCSymbol *Func) {
205 llvm_unreachable("not implemented");
208 void WinCOFFStreamer::EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) {
209 assert((Symbol->isInSection()
210 ? Symbol->getSection().getVariant() == MCSection::SV_COFF
211 : true) && "Got non COFF section in the COFF backend!");
212 // FIXME: This is all very ugly and depressing. What needs to happen here
213 // depends on quite a few things that are all part of relaxation, which we
214 // don't really even do.
216 if (Value->getKind() != MCExpr::SymbolRef) {
217 // TODO: This is exactly the same as MachOStreamer. Consider merging into
219 getAssembler().getOrCreateSymbolData(*Symbol);
220 AddValueSymbols(Value);
221 Symbol->setVariableValue(Value);
223 // FIXME: This is a horrible way to do this :(. This should really be
224 // handled after we are done with the MC* objects and immediately before
225 // writing out the object file when we know exactly what the symbol should
226 // look like in the coff symbol table. I'm not doing that now because the
227 // COFF object writer doesn't have a clearly defined separation between MC
228 // data structures, the object writers data structures, and the raw, POD,
229 // data structures that get written to disk.
231 // Copy over the aliased data.
232 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
233 const MCSymbolData &RealSD = getAssembler().getOrCreateSymbolData(
234 dyn_cast<const MCSymbolRefExpr>(Value)->getSymbol());
236 // FIXME: This is particularly nasty because it breaks as soon as any data
237 // members of MCSymbolData change.
238 SD.CommonAlign = RealSD.CommonAlign;
239 SD.CommonSize = RealSD.CommonSize;
240 SD.Flags = RealSD.Flags;
241 SD.Fragment = RealSD.Fragment;
242 SD.Index = RealSD.Index;
243 SD.IsExternal = RealSD.IsExternal;
244 SD.IsPrivateExtern = RealSD.IsPrivateExtern;
245 SD.Offset = RealSD.Offset;
246 SD.SymbolSize = RealSD.SymbolSize;
250 void WinCOFFStreamer::EmitSymbolAttribute(MCSymbol *Symbol,
251 MCSymbolAttr Attribute) {
252 assert(Symbol && "Symbol must be non-null!");
253 assert((Symbol->isInSection()
254 ? Symbol->getSection().getVariant() == MCSection::SV_COFF
255 : true) && "Got non COFF section in the COFF backend!");
257 case MCSA_WeakReference:
259 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
260 SD.modifyFlags(COFF::SF_WeakExternal, COFF::SF_WeakExternal);
261 SD.setExternal(true);
266 getAssembler().getOrCreateSymbolData(*Symbol).setExternal(true);
270 llvm_unreachable("unsupported attribute");
275 void WinCOFFStreamer::EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {
276 llvm_unreachable("not implemented");
279 void WinCOFFStreamer::BeginCOFFSymbolDef(MCSymbol const *Symbol) {
280 assert((Symbol->isInSection()
281 ? Symbol->getSection().getVariant() == MCSection::SV_COFF
282 : true) && "Got non COFF section in the COFF backend!");
283 assert(CurSymbol == NULL && "EndCOFFSymbolDef must be called between calls "
284 "to BeginCOFFSymbolDef!");
288 void WinCOFFStreamer::EmitCOFFSymbolStorageClass(int StorageClass) {
289 assert(CurSymbol != NULL && "BeginCOFFSymbolDef must be called first!");
290 assert((StorageClass & ~0xFF) == 0 && "StorageClass must only have data in "
293 getAssembler().getOrCreateSymbolData(*CurSymbol).modifyFlags(
294 StorageClass << COFF::SF_ClassShift,
298 void WinCOFFStreamer::EmitCOFFSymbolType(int Type) {
299 assert(CurSymbol != NULL && "BeginCOFFSymbolDef must be called first!");
300 assert((Type & ~0xFFFF) == 0 && "Type must only have data in the first 2 "
303 getAssembler().getOrCreateSymbolData(*CurSymbol).modifyFlags(
304 Type << COFF::SF_TypeShift,
308 void WinCOFFStreamer::EndCOFFSymbolDef() {
309 assert(CurSymbol != NULL && "BeginCOFFSymbolDef must be called first!");
313 void WinCOFFStreamer::EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) {
314 llvm_unreachable("not implemented");
317 void WinCOFFStreamer::EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
318 unsigned ByteAlignment) {
319 assert((Symbol->isInSection()
320 ? Symbol->getSection().getVariant() == MCSection::SV_COFF
321 : true) && "Got non COFF section in the COFF backend!");
322 AddCommonSymbol(Symbol, Size, ByteAlignment, true);
325 void WinCOFFStreamer::EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size) {
326 assert((Symbol->isInSection()
327 ? Symbol->getSection().getVariant() == MCSection::SV_COFF
328 : true) && "Got non COFF section in the COFF backend!");
329 AddCommonSymbol(Symbol, Size, 1, false);
332 void WinCOFFStreamer::EmitZerofill(const MCSection *Section, MCSymbol *Symbol,
333 unsigned Size,unsigned ByteAlignment) {
334 llvm_unreachable("not implemented");
337 void WinCOFFStreamer::EmitTBSSSymbol(const MCSection *Section, MCSymbol *Symbol,
338 uint64_t Size, unsigned ByteAlignment) {
339 llvm_unreachable("not implemented");
342 void WinCOFFStreamer::EmitBytes(StringRef Data, unsigned AddrSpace) {
343 // TODO: This is copied exactly from the MachOStreamer. Consider merging into
345 getOrCreateDataFragment()->getContents().append(Data.begin(), Data.end());
348 void WinCOFFStreamer::EmitValue(const MCExpr *Value, unsigned Size,
349 unsigned AddrSpace) {
350 assert(AddrSpace == 0 && "Address space must be 0!");
352 // TODO: This is copied exactly from the MachOStreamer. Consider merging into
354 MCDataFragment *DF = getOrCreateDataFragment();
356 // Avoid fixups when possible.
358 if (AddValueSymbols(Value)->EvaluateAsAbsolute(AbsValue)) {
359 // FIXME: Endianness assumption.
360 for (unsigned i = 0; i != Size; ++i)
361 DF->getContents().push_back(uint8_t(AbsValue >> (i * 8)));
363 DF->addFixup(MCFixup::Create(DF->getContents().size(),
364 AddValueSymbols(Value),
365 MCFixup::getKindForSize(Size, false)));
366 DF->getContents().resize(DF->getContents().size() + Size, 0);
370 void WinCOFFStreamer::EmitValueToAlignment(unsigned ByteAlignment,
373 unsigned MaxBytesToEmit) {
374 // TODO: This is copied exactly from the MachOStreamer. Consider merging into
376 if (MaxBytesToEmit == 0)
377 MaxBytesToEmit = ByteAlignment;
378 new MCAlignFragment(ByteAlignment, Value, ValueSize, MaxBytesToEmit,
379 getCurrentSectionData());
381 // Update the maximum alignment on the current section if necessary.
382 if (ByteAlignment > getCurrentSectionData()->getAlignment())
383 getCurrentSectionData()->setAlignment(ByteAlignment);
386 void WinCOFFStreamer::EmitCodeAlignment(unsigned ByteAlignment,
387 unsigned MaxBytesToEmit) {
388 // TODO: This is copied exactly from the MachOStreamer. Consider merging into
390 if (MaxBytesToEmit == 0)
391 MaxBytesToEmit = ByteAlignment;
392 MCAlignFragment *F = new MCAlignFragment(ByteAlignment, 0, 1, MaxBytesToEmit,
393 getCurrentSectionData());
394 F->setEmitNops(true);
396 // Update the maximum alignment on the current section if necessary.
397 if (ByteAlignment > getCurrentSectionData()->getAlignment())
398 getCurrentSectionData()->setAlignment(ByteAlignment);
401 void WinCOFFStreamer::EmitValueToOffset(const MCExpr *Offset,
402 unsigned char Value) {
403 llvm_unreachable("not implemented");
406 void WinCOFFStreamer::EmitFileDirective(StringRef Filename) {
407 // Ignore for now, linkers don't care, and proper debug
408 // info will be a much large effort.
411 void WinCOFFStreamer::EmitInstruction(const MCInst &Instruction) {
412 for (unsigned i = 0, e = Instruction.getNumOperands(); i != e; ++i)
413 if (Instruction.getOperand(i).isExpr())
414 AddValueSymbols(Instruction.getOperand(i).getExpr());
416 getCurrentSectionData()->setHasInstructions(true);
418 MCInstFragment *Fragment =
419 new MCInstFragment(Instruction, getCurrentSectionData());
421 raw_svector_ostream VecOS(Fragment->getCode());
423 getAssembler().getEmitter().EncodeInstruction(Instruction, VecOS,
424 Fragment->getFixups());
427 void WinCOFFStreamer::Finish() {
428 MCObjectStreamer::Finish();
433 MCStreamer *createWinCOFFStreamer(MCContext &Context,
434 TargetAsmBackend &TAB,
438 WinCOFFStreamer *S = new WinCOFFStreamer(Context, TAB, CE, OS);
439 S->getAssembler().setRelaxAll(RelaxAll);