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 Windows COFF object file streamer.
12 //===----------------------------------------------------------------------===//
14 #include "llvm/MC/MCAsmBackend.h"
15 #include "llvm/MC/MCAsmLayout.h"
16 #include "llvm/MC/MCAssembler.h"
17 #include "llvm/MC/MCCodeEmitter.h"
18 #include "llvm/MC/MCContext.h"
19 #include "llvm/MC/MCExpr.h"
20 #include "llvm/MC/MCObjectFileInfo.h"
21 #include "llvm/MC/MCObjectStreamer.h"
22 #include "llvm/MC/MCSection.h"
23 #include "llvm/MC/MCSectionCOFF.h"
24 #include "llvm/MC/MCStreamer.h"
25 #include "llvm/MC/MCSymbolCOFF.h"
26 #include "llvm/MC/MCValue.h"
27 #include "llvm/MC/MCWinCOFFStreamer.h"
28 #include "llvm/Support/COFF.h"
29 #include "llvm/Support/Debug.h"
30 #include "llvm/Support/ErrorHandling.h"
31 #include "llvm/Support/MathExtras.h"
32 #include "llvm/Support/TargetRegistry.h"
33 #include "llvm/Support/raw_ostream.h"
37 #define DEBUG_TYPE "WinCOFFStreamer"
40 MCWinCOFFStreamer::MCWinCOFFStreamer(MCContext &Context, MCAsmBackend &MAB,
41 MCCodeEmitter &CE, raw_pwrite_stream &OS)
42 : MCObjectStreamer(Context, MAB, OS, &CE), CurSymbol(nullptr) {}
44 void MCWinCOFFStreamer::EmitInstToData(const MCInst &Inst,
45 const MCSubtargetInfo &STI) {
46 MCDataFragment *DF = getOrCreateDataFragment();
48 SmallVector<MCFixup, 4> Fixups;
49 SmallString<256> Code;
50 raw_svector_ostream VecOS(Code);
51 getAssembler().getEmitter().encodeInstruction(Inst, VecOS, Fixups, STI);
54 // Add the fixups and data.
55 for (unsigned i = 0, e = Fixups.size(); i != e; ++i) {
56 Fixups[i].setOffset(Fixups[i].getOffset() + DF->getContents().size());
57 DF->getFixups().push_back(Fixups[i]);
60 DF->getContents().append(Code.begin(), Code.end());
63 void MCWinCOFFStreamer::InitSections(bool NoExecStack) {
64 // FIXME: this is identical to the ELF one.
65 // This emulates the same behavior of GNU as. This makes it easier
66 // to compare the output as the major sections are in the same order.
67 SwitchSection(getContext().getObjectFileInfo()->getTextSection());
70 SwitchSection(getContext().getObjectFileInfo()->getDataSection());
73 SwitchSection(getContext().getObjectFileInfo()->getBSSSection());
76 SwitchSection(getContext().getObjectFileInfo()->getTextSection());
79 void MCWinCOFFStreamer::EmitLabel(MCSymbol *Symbol) {
80 assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
81 MCObjectStreamer::EmitLabel(Symbol);
84 void MCWinCOFFStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) {
85 llvm_unreachable("not implemented");
88 void MCWinCOFFStreamer::EmitThumbFunc(MCSymbol *Func) {
89 llvm_unreachable("not implemented");
92 bool MCWinCOFFStreamer::EmitSymbolAttribute(MCSymbol *Symbol,
93 MCSymbolAttr Attribute) {
94 assert(Symbol && "Symbol must be non-null!");
95 assert((!Symbol->isInSection() ||
96 Symbol->getSection().getVariant() == MCSection::SV_COFF) &&
97 "Got non-COFF section in the COFF backend!");
99 getAssembler().registerSymbol(*Symbol);
102 default: return false;
103 case MCSA_WeakReference:
105 cast<MCSymbolCOFF>(Symbol)->setIsWeakExternal();
106 Symbol->setExternal(true);
109 Symbol->setExternal(true);
116 void MCWinCOFFStreamer::EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {
117 llvm_unreachable("not implemented");
120 void MCWinCOFFStreamer::BeginCOFFSymbolDef(MCSymbol const *Symbol) {
121 assert((!Symbol->isInSection() ||
122 Symbol->getSection().getVariant() == MCSection::SV_COFF) &&
123 "Got non-COFF section in the COFF backend!");
126 FatalError("starting a new symbol definition without completing the "
131 void MCWinCOFFStreamer::EmitCOFFSymbolStorageClass(int StorageClass) {
133 FatalError("storage class specified outside of symbol definition");
135 if (StorageClass & ~COFF::SSC_Invalid)
136 FatalError("storage class value '" + Twine(StorageClass) +
139 getAssembler().registerSymbol(*CurSymbol);
140 cast<MCSymbolCOFF>(CurSymbol)->setClass((uint16_t)StorageClass);
143 void MCWinCOFFStreamer::EmitCOFFSymbolType(int Type) {
145 FatalError("symbol type specified outside of a symbol definition");
148 FatalError("type value '" + Twine(Type) + "' out of range");
150 getAssembler().registerSymbol(*CurSymbol);
151 cast<MCSymbolCOFF>(CurSymbol)->setType((uint16_t)Type);
154 void MCWinCOFFStreamer::EndCOFFSymbolDef() {
156 FatalError("ending symbol definition without starting one");
160 void MCWinCOFFStreamer::EmitCOFFSafeSEH(MCSymbol const *Symbol) {
161 // SafeSEH is a feature specific to 32-bit x86. It does not exist (and is
162 // unnecessary) on all platforms which use table-based exception dispatch.
163 if (getContext().getObjectFileInfo()->getTargetTriple().getArch() !=
167 const MCSymbolCOFF *CSymbol = cast<MCSymbolCOFF>(Symbol);
168 if (CSymbol->isSafeSEH())
171 MCSection *SXData = getContext().getObjectFileInfo()->getSXDataSection();
172 getAssembler().registerSection(*SXData);
173 if (SXData->getAlignment() < 4)
174 SXData->setAlignment(4);
176 new MCSafeSEHFragment(Symbol, SXData);
178 getAssembler().registerSymbol(*Symbol);
179 CSymbol->setIsSafeSEH();
181 // The Microsoft linker requires that the symbol type of a handler be
182 // function. Go ahead and oblige it here.
183 CSymbol->setType(COFF::IMAGE_SYM_DTYPE_FUNCTION
184 << COFF::SCT_COMPLEX_TYPE_SHIFT);
187 void MCWinCOFFStreamer::EmitCOFFSectionIndex(MCSymbol const *Symbol) {
188 MCDataFragment *DF = getOrCreateDataFragment();
189 const MCSymbolRefExpr *SRE = MCSymbolRefExpr::create(Symbol, getContext());
190 MCFixup Fixup = MCFixup::create(DF->getContents().size(), SRE, FK_SecRel_2);
191 DF->getFixups().push_back(Fixup);
192 DF->getContents().resize(DF->getContents().size() + 2, 0);
195 void MCWinCOFFStreamer::EmitCOFFSecRel32(MCSymbol const *Symbol) {
196 MCDataFragment *DF = getOrCreateDataFragment();
197 const MCSymbolRefExpr *SRE = MCSymbolRefExpr::create(Symbol, getContext());
198 MCFixup Fixup = MCFixup::create(DF->getContents().size(), SRE, FK_SecRel_4);
199 DF->getFixups().push_back(Fixup);
200 DF->getContents().resize(DF->getContents().size() + 4, 0);
203 void MCWinCOFFStreamer::EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
204 unsigned ByteAlignment) {
205 assert((!Symbol->isInSection() ||
206 Symbol->getSection().getVariant() == MCSection::SV_COFF) &&
207 "Got non-COFF section in the COFF backend!");
209 const Triple &T = getContext().getObjectFileInfo()->getTargetTriple();
210 if (T.isKnownWindowsMSVCEnvironment()) {
211 if (ByteAlignment > 32)
212 report_fatal_error("alignment is limited to 32-bytes");
214 // Round size up to alignment so that we will honor the alignment request.
215 Size = std::max(Size, static_cast<uint64_t>(ByteAlignment));
218 AssignSection(Symbol, nullptr);
220 getAssembler().registerSymbol(*Symbol);
221 Symbol->setExternal(true);
222 Symbol->setCommon(Size, ByteAlignment);
224 if (!T.isKnownWindowsMSVCEnvironment() && ByteAlignment > 1) {
225 SmallString<128> Directive;
226 raw_svector_ostream OS(Directive);
227 const MCObjectFileInfo *MFI = getContext().getObjectFileInfo();
229 OS << " -aligncomm:\"" << Symbol->getName() << "\","
230 << Log2_32_Ceil(ByteAlignment);
234 SwitchSection(MFI->getDrectveSection());
235 EmitBytes(Directive);
240 void MCWinCOFFStreamer::EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
241 unsigned ByteAlignment) {
242 assert(!Symbol->isInSection() && "Symbol must not already have a section!");
244 MCSection *Section = getContext().getObjectFileInfo()->getBSSSection();
245 getAssembler().registerSection(*Section);
246 if (Section->getAlignment() < ByteAlignment)
247 Section->setAlignment(ByteAlignment);
249 getAssembler().registerSymbol(*Symbol);
250 Symbol->setExternal(false);
252 AssignSection(Symbol, Section);
254 if (ByteAlignment != 1)
255 new MCAlignFragment(ByteAlignment, /*Value=*/0, /*ValueSize=*/0,
256 ByteAlignment, Section);
258 MCFillFragment *Fragment = new MCFillFragment(
259 /*Value=*/0, /*ValueSize=*/0, Size, Section);
260 Symbol->setFragment(Fragment);
263 void MCWinCOFFStreamer::EmitZerofill(MCSection *Section, MCSymbol *Symbol,
264 uint64_t Size, unsigned ByteAlignment) {
265 llvm_unreachable("not implemented");
268 void MCWinCOFFStreamer::EmitTBSSSymbol(MCSection *Section, MCSymbol *Symbol,
269 uint64_t Size, unsigned ByteAlignment) {
270 llvm_unreachable("not implemented");
273 void MCWinCOFFStreamer::EmitFileDirective(StringRef Filename) {
274 getAssembler().addFileName(Filename);
277 // TODO: Implement this if you want to emit .comment section in COFF obj files.
278 void MCWinCOFFStreamer::EmitIdent(StringRef IdentString) {
279 llvm_unreachable("not implemented");
282 void MCWinCOFFStreamer::EmitWinEHHandlerData() {
283 llvm_unreachable("not implemented");
286 void MCWinCOFFStreamer::FinishImpl() {
287 MCObjectStreamer::FinishImpl();
290 LLVM_ATTRIBUTE_NORETURN
291 void MCWinCOFFStreamer::FatalError(const Twine &Msg) const {
292 getContext().reportFatalError(SMLoc(), Msg);