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/MCObjectStreamer.h"
24 #include "llvm/MC/MCSection.h"
25 #include "llvm/MC/MCSectionCOFF.h"
26 #include "llvm/MC/MCSymbol.h"
27 #include "llvm/MC/MCValue.h"
28 #include "llvm/MC/MCWin64EH.h"
29 #include "llvm/Support/COFF.h"
30 #include "llvm/Support/Debug.h"
31 #include "llvm/Support/ErrorHandling.h"
32 #include "llvm/Support/TargetRegistry.h"
33 #include "llvm/Support/raw_ostream.h"
38 class WinCOFFStreamer : public MCObjectStreamer {
40 MCSymbol const *CurSymbol;
42 WinCOFFStreamer(MCContext &Context,
47 void AddCommonSymbol(MCSymbol *Symbol, uint64_t Size,
48 unsigned ByteAlignment, bool External);
50 // MCStreamer interface
52 virtual void InitSections();
53 virtual void EmitLabel(MCSymbol *Symbol);
54 virtual void EmitDebugLabel(MCSymbol *Symbol);
55 virtual void EmitAssemblerFlag(MCAssemblerFlag Flag);
56 virtual void EmitThumbFunc(MCSymbol *Func);
57 virtual void EmitAssignment(MCSymbol *Symbol, const MCExpr *Value);
58 virtual void EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute);
59 virtual void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue);
60 virtual void BeginCOFFSymbolDef(MCSymbol const *Symbol);
61 virtual void EmitCOFFSymbolStorageClass(int StorageClass);
62 virtual void EmitCOFFSymbolType(int Type);
63 virtual void EndCOFFSymbolDef();
64 virtual void EmitCOFFSecRel32(MCSymbol const *Symbol);
65 virtual void EmitELFSize(MCSymbol *Symbol, const MCExpr *Value);
66 virtual void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
67 unsigned ByteAlignment);
68 virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
69 unsigned ByteAlignment);
70 virtual void EmitZerofill(const MCSection *Section, MCSymbol *Symbol,
71 uint64_t Size,unsigned ByteAlignment);
72 virtual void EmitTBSSSymbol(const MCSection *Section, MCSymbol *Symbol,
73 uint64_t Size, unsigned ByteAlignment);
74 virtual void EmitFileDirective(StringRef Filename);
75 virtual void EmitInstruction(const MCInst &Instruction);
76 virtual void EmitWin64EHHandlerData();
77 virtual void FinishImpl();
80 virtual void EmitInstToFragment(const MCInst &Inst) {
81 llvm_unreachable("Not used by WinCOFF.");
83 virtual void EmitInstToData(const MCInst &Inst) {
84 llvm_unreachable("Not used by WinCOFF.");
87 void SetSection(StringRef Section,
88 unsigned Characteristics,
90 SwitchSection(getContext().getCOFFSection(Section, Characteristics, Kind));
93 void SetSectionText() {
95 COFF::IMAGE_SCN_CNT_CODE
96 | COFF::IMAGE_SCN_MEM_EXECUTE
97 | COFF::IMAGE_SCN_MEM_READ,
98 SectionKind::getText());
99 EmitCodeAlignment(4, 0);
102 void SetSectionData() {
104 COFF::IMAGE_SCN_CNT_INITIALIZED_DATA
105 | COFF::IMAGE_SCN_MEM_READ
106 | COFF::IMAGE_SCN_MEM_WRITE,
107 SectionKind::getDataRel());
108 EmitCodeAlignment(4, 0);
111 void SetSectionBSS() {
113 COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA
114 | COFF::IMAGE_SCN_MEM_READ
115 | COFF::IMAGE_SCN_MEM_WRITE,
116 SectionKind::getBSS());
117 EmitCodeAlignment(4, 0);
121 } // end anonymous namespace.
123 WinCOFFStreamer::WinCOFFStreamer(MCContext &Context,
127 : MCObjectStreamer(Context, MAB, OS, &CE)
131 void WinCOFFStreamer::AddCommonSymbol(MCSymbol *Symbol, uint64_t Size,
132 unsigned ByteAlignment, bool External) {
133 assert(!Symbol->isInSection() && "Symbol must not already have a section!");
135 std::string SectionName(".bss$linkonce");
136 SectionName.append(Symbol->getName().begin(), Symbol->getName().end());
138 MCSymbolData &SymbolData = getAssembler().getOrCreateSymbolData(*Symbol);
140 unsigned Characteristics =
141 COFF::IMAGE_SCN_LNK_COMDAT |
142 COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA |
143 COFF::IMAGE_SCN_MEM_READ |
144 COFF::IMAGE_SCN_MEM_WRITE;
146 int Selection = COFF::IMAGE_COMDAT_SELECT_LARGEST;
148 const MCSection *Section = MCStreamer::getContext().getCOFFSection(
149 SectionName, Characteristics, Selection, SectionKind::getBSS());
151 MCSectionData &SectionData = getAssembler().getOrCreateSectionData(*Section);
153 if (SectionData.getAlignment() < ByteAlignment)
154 SectionData.setAlignment(ByteAlignment);
156 SymbolData.setExternal(External);
158 Symbol->setSection(*Section);
160 if (ByteAlignment != 1)
161 new MCAlignFragment(ByteAlignment, 0, 0, ByteAlignment, &SectionData);
163 SymbolData.setFragment(new MCFillFragment(0, 0, Size, &SectionData));
166 // MCStreamer interface
168 void WinCOFFStreamer::InitSections() {
175 void WinCOFFStreamer::EmitLabel(MCSymbol *Symbol) {
176 assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
177 MCObjectStreamer::EmitLabel(Symbol);
180 void WinCOFFStreamer::EmitDebugLabel(MCSymbol *Symbol) {
183 void WinCOFFStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) {
184 llvm_unreachable("not implemented");
187 void WinCOFFStreamer::EmitThumbFunc(MCSymbol *Func) {
188 llvm_unreachable("not implemented");
191 void WinCOFFStreamer::EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) {
192 assert((Symbol->isInSection()
193 ? Symbol->getSection().getVariant() == MCSection::SV_COFF
194 : true) && "Got non COFF section in the COFF backend!");
195 // FIXME: This is all very ugly and depressing. What needs to happen here
196 // depends on quite a few things that are all part of relaxation, which we
197 // don't really even do.
199 if (Value->getKind() != MCExpr::SymbolRef) {
200 MCObjectStreamer::EmitAssignment(Symbol, Value);
202 // FIXME: This is a horrible way to do this :(. This should really be
203 // handled after we are done with the MC* objects and immediately before
204 // writing out the object file when we know exactly what the symbol should
205 // look like in the coff symbol table. I'm not doing that now because the
206 // COFF object writer doesn't have a clearly defined separation between MC
207 // data structures, the object writers data structures, and the raw, POD,
208 // data structures that get written to disk.
210 // Copy over the aliased data.
211 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
212 const MCSymbolData &RealSD = getAssembler().getOrCreateSymbolData(
213 dyn_cast<const MCSymbolRefExpr>(Value)->getSymbol());
215 // FIXME: This is particularly nasty because it breaks as soon as any data
216 // members of MCSymbolData change.
217 SD.CommonAlign = RealSD.CommonAlign;
218 SD.CommonSize = RealSD.CommonSize;
219 SD.Flags = RealSD.Flags;
220 SD.Fragment = RealSD.Fragment;
221 SD.Index = RealSD.Index;
222 SD.IsExternal = RealSD.IsExternal;
223 SD.IsPrivateExtern = RealSD.IsPrivateExtern;
224 SD.Offset = RealSD.Offset;
225 SD.SymbolSize = RealSD.SymbolSize;
229 void WinCOFFStreamer::EmitSymbolAttribute(MCSymbol *Symbol,
230 MCSymbolAttr Attribute) {
231 assert(Symbol && "Symbol must be non-null!");
232 assert((Symbol->isInSection()
233 ? Symbol->getSection().getVariant() == MCSection::SV_COFF
234 : true) && "Got non COFF section in the COFF backend!");
236 case MCSA_WeakReference:
238 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
239 SD.modifyFlags(COFF::SF_WeakExternal, COFF::SF_WeakExternal);
240 SD.setExternal(true);
245 getAssembler().getOrCreateSymbolData(*Symbol).setExternal(true);
249 llvm_unreachable("unsupported attribute");
253 void WinCOFFStreamer::EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {
254 llvm_unreachable("not implemented");
257 void WinCOFFStreamer::BeginCOFFSymbolDef(MCSymbol const *Symbol) {
258 assert((Symbol->isInSection()
259 ? Symbol->getSection().getVariant() == MCSection::SV_COFF
260 : true) && "Got non COFF section in the COFF backend!");
261 assert(CurSymbol == NULL && "EndCOFFSymbolDef must be called between calls "
262 "to BeginCOFFSymbolDef!");
266 void WinCOFFStreamer::EmitCOFFSymbolStorageClass(int StorageClass) {
267 assert(CurSymbol != NULL && "BeginCOFFSymbolDef must be called first!");
268 assert((StorageClass & ~0xFF) == 0 && "StorageClass must only have data in "
271 getAssembler().getOrCreateSymbolData(*CurSymbol).modifyFlags(
272 StorageClass << COFF::SF_ClassShift,
276 void WinCOFFStreamer::EmitCOFFSymbolType(int Type) {
277 assert(CurSymbol != NULL && "BeginCOFFSymbolDef must be called first!");
278 assert((Type & ~0xFFFF) == 0 && "Type must only have data in the first 2 "
281 getAssembler().getOrCreateSymbolData(*CurSymbol).modifyFlags(
282 Type << COFF::SF_TypeShift,
286 void WinCOFFStreamer::EndCOFFSymbolDef() {
287 assert(CurSymbol != NULL && "BeginCOFFSymbolDef must be called first!");
291 void WinCOFFStreamer::EmitCOFFSecRel32(MCSymbol const *Symbol)
293 MCDataFragment *DF = getOrCreateDataFragment();
295 DF->getFixups().push_back(
296 MCFixup::Create(DF->getContents().size(),
297 MCSymbolRefExpr::Create (Symbol, getContext ()),
299 DF->getContents().resize(DF->getContents().size() + 4, 0);
302 void WinCOFFStreamer::EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) {
303 llvm_unreachable("not implemented");
306 void WinCOFFStreamer::EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
307 unsigned ByteAlignment) {
308 assert((Symbol->isInSection()
309 ? Symbol->getSection().getVariant() == MCSection::SV_COFF
310 : true) && "Got non COFF section in the COFF backend!");
311 AddCommonSymbol(Symbol, Size, ByteAlignment, true);
314 void WinCOFFStreamer::EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
315 unsigned ByteAlignment) {
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, ByteAlignment, false);
322 void WinCOFFStreamer::EmitZerofill(const MCSection *Section, MCSymbol *Symbol,
323 uint64_t 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::EmitFileDirective(StringRef Filename) {
333 // Ignore for now, linkers don't care, and proper debug
334 // info will be a much large effort.
337 void WinCOFFStreamer::EmitInstruction(const MCInst &Instruction) {
338 for (unsigned i = 0, e = Instruction.getNumOperands(); i != e; ++i)
339 if (Instruction.getOperand(i).isExpr())
340 AddValueSymbols(Instruction.getOperand(i).getExpr());
342 getCurrentSectionData()->setHasInstructions(true);
344 MCInstFragment *Fragment =
345 new MCInstFragment(Instruction, getCurrentSectionData());
347 raw_svector_ostream VecOS(Fragment->getContents());
349 getAssembler().getEmitter().EncodeInstruction(Instruction, VecOS,
350 Fragment->getFixups());
353 void WinCOFFStreamer::EmitWin64EHHandlerData() {
354 MCStreamer::EmitWin64EHHandlerData();
356 // We have to emit the unwind info now, because this directive
357 // actually switches to the .xdata section!
358 MCWin64EHUnwindEmitter::EmitUnwindInfo(*this, getCurrentW64UnwindInfo());
361 void WinCOFFStreamer::FinishImpl() {
363 MCObjectStreamer::FinishImpl();
368 MCStreamer *createWinCOFFStreamer(MCContext &Context,
373 WinCOFFStreamer *S = new WinCOFFStreamer(Context, MAB, CE, OS);
374 S->getAssembler().setRelaxAll(RelaxAll);