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/ADT/StringExtras.h"
15 #include "llvm/MC/MCStreamer.h"
16 #include "llvm/MC/MCAsmBackend.h"
17 #include "llvm/MC/MCAsmLayout.h"
18 #include "llvm/MC/MCAssembler.h"
19 #include "llvm/MC/MCCodeEmitter.h"
20 #include "llvm/MC/MCContext.h"
21 #include "llvm/MC/MCExpr.h"
22 #include "llvm/MC/MCObjectFileInfo.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/MCWinCOFFStreamer.h"
29 #include "llvm/Support/COFF.h"
30 #include "llvm/Support/Debug.h"
31 #include "llvm/Support/ErrorHandling.h"
32 #include "llvm/Support/MathExtras.h"
33 #include "llvm/Support/TargetRegistry.h"
34 #include "llvm/Support/raw_ostream.h"
38 #define DEBUG_TYPE "WinCOFFStreamer"
41 MCWinCOFFStreamer::MCWinCOFFStreamer(MCContext &Context, MCAsmBackend &MAB,
42 MCCodeEmitter &CE, raw_ostream &OS)
43 : MCObjectStreamer(Context, MAB, OS, &CE), CurSymbol(nullptr) {}
45 void MCWinCOFFStreamer::EmitInstToData(const MCInst &Inst,
46 const MCSubtargetInfo &STI) {
47 MCDataFragment *DF = getOrCreateDataFragment();
49 SmallVector<MCFixup, 4> Fixups;
50 SmallString<256> Code;
51 raw_svector_ostream VecOS(Code);
52 getAssembler().getEmitter().EncodeInstruction(Inst, VecOS, Fixups, STI);
55 // Add the fixups and data.
56 for (unsigned i = 0, e = Fixups.size(); i != e; ++i) {
57 Fixups[i].setOffset(Fixups[i].getOffset() + DF->getContents().size());
58 DF->getFixups().push_back(Fixups[i]);
61 DF->getContents().append(Code.begin(), Code.end());
64 void MCWinCOFFStreamer::InitSections() {
65 // FIXME: this is identical to the ELF one.
66 // This emulates the same behavior of GNU as. This makes it easier
67 // to compare the output as the major sections are in the same order.
68 SwitchSection(getContext().getObjectFileInfo()->getTextSection());
71 SwitchSection(getContext().getObjectFileInfo()->getDataSection());
74 SwitchSection(getContext().getObjectFileInfo()->getBSSSection());
77 SwitchSection(getContext().getObjectFileInfo()->getTextSection());
80 void MCWinCOFFStreamer::EmitLabel(MCSymbol *Symbol) {
81 assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
82 MCObjectStreamer::EmitLabel(Symbol);
85 void MCWinCOFFStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) {
86 llvm_unreachable("not implemented");
89 void MCWinCOFFStreamer::EmitThumbFunc(MCSymbol *Func) {
90 llvm_unreachable("not implemented");
93 bool MCWinCOFFStreamer::EmitSymbolAttribute(MCSymbol *Symbol,
94 MCSymbolAttr Attribute) {
95 assert(Symbol && "Symbol must be non-null!");
96 assert((!Symbol->isInSection() ||
97 Symbol->getSection().getVariant() == MCSection::SV_COFF) &&
98 "Got non-COFF section in the COFF backend!");
100 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
103 default: return false;
104 case MCSA_WeakReference:
106 SD.modifyFlags(COFF::SF_WeakExternal, COFF::SF_WeakExternal);
107 SD.setExternal(true);
110 SD.setExternal(true);
117 void MCWinCOFFStreamer::EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {
118 llvm_unreachable("not implemented");
121 void MCWinCOFFStreamer::BeginCOFFSymbolDef(MCSymbol const *Symbol) {
122 assert((!Symbol->isInSection() ||
123 Symbol->getSection().getVariant() == MCSection::SV_COFF) &&
124 "Got non-COFF section in the COFF backend!");
127 FatalError("starting a new symbol definition without completing the "
132 void MCWinCOFFStreamer::EmitCOFFSymbolStorageClass(int StorageClass) {
134 FatalError("storage class specified outside of symbol definition");
136 if (StorageClass & ~0xff)
137 FatalError(Twine("storage class value '") + itostr(StorageClass) +
140 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*CurSymbol);
141 SD.modifyFlags(StorageClass << COFF::SF_ClassShift, COFF::SF_ClassMask);
144 void MCWinCOFFStreamer::EmitCOFFSymbolType(int Type) {
146 FatalError("symbol type specified outside of a symbol definition");
149 FatalError(Twine("type value '") + itostr(Type) + "' out of range");
151 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*CurSymbol);
152 SD.modifyFlags(Type << COFF::SF_TypeShift, COFF::SF_TypeMask);
155 void MCWinCOFFStreamer::EndCOFFSymbolDef() {
157 FatalError("ending symbol definition without starting one");
161 void MCWinCOFFStreamer::EmitCOFFSectionIndex(MCSymbol const *Symbol) {
162 MCDataFragment *DF = getOrCreateDataFragment();
163 const MCSymbolRefExpr *SRE = MCSymbolRefExpr::Create(Symbol, getContext());
164 MCFixup Fixup = MCFixup::Create(DF->getContents().size(), SRE, FK_SecRel_2);
165 DF->getFixups().push_back(Fixup);
166 DF->getContents().resize(DF->getContents().size() + 4, 0);
169 void MCWinCOFFStreamer::EmitCOFFSecRel32(MCSymbol const *Symbol) {
170 MCDataFragment *DF = getOrCreateDataFragment();
171 const MCSymbolRefExpr *SRE = MCSymbolRefExpr::Create(Symbol, getContext());
172 MCFixup Fixup = MCFixup::Create(DF->getContents().size(), SRE, FK_SecRel_4);
173 DF->getFixups().push_back(Fixup);
174 DF->getContents().resize(DF->getContents().size() + 4, 0);
177 void MCWinCOFFStreamer::EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) {
178 llvm_unreachable("not supported");
181 void MCWinCOFFStreamer::EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
182 unsigned ByteAlignment) {
183 assert((!Symbol->isInSection() ||
184 Symbol->getSection().getVariant() == MCSection::SV_COFF) &&
185 "Got non-COFF section in the COFF backend!");
187 const Triple &T = getContext().getObjectFileInfo()->getTargetTriple();
188 if (T.isKnownWindowsMSVCEnvironment())
189 if (ByteAlignment > 32)
190 report_fatal_error("alignment is limited to 32-bytes");
192 // Round size up to alignment so that we will honor the alignment request.
193 // TODO: We don't need to do this if we are targeting the bfd linker once we
194 // add support for adding -aligncomm into the .drectve section.
195 Size = std::max(Size, static_cast<uint64_t>(ByteAlignment));
197 AssignSection(Symbol, nullptr);
199 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
200 SD.setExternal(true);
201 SD.setCommon(Size, ByteAlignment);
203 if (!T.isKnownWindowsMSVCEnvironment() && ByteAlignment > 1) {
204 SmallString<128> Directive;
205 raw_svector_ostream OS(Directive);
206 const MCObjectFileInfo *MFI = getContext().getObjectFileInfo();
208 OS << " -aligncomm:\"" << Symbol->getName() << "\","
209 << Log2_32_Ceil(ByteAlignment);
213 SwitchSection(MFI->getDrectveSection());
214 EmitBytes(Directive);
219 void MCWinCOFFStreamer::EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
220 unsigned ByteAlignment) {
221 assert(!Symbol->isInSection() && "Symbol must not already have a section!");
223 const MCSection *Section = getContext().getObjectFileInfo()->getBSSSection();
224 MCSectionData &SectionData = getAssembler().getOrCreateSectionData(*Section);
225 if (SectionData.getAlignment() < ByteAlignment)
226 SectionData.setAlignment(ByteAlignment);
228 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
229 SD.setExternal(false);
231 AssignSection(Symbol, Section);
233 if (ByteAlignment != 1)
234 new MCAlignFragment(ByteAlignment, /*_Value=*/0, /*_ValueSize=*/0,
235 ByteAlignment, &SectionData);
237 MCFillFragment *Fragment =
238 new MCFillFragment(/*_Value=*/0, /*_ValueSize=*/0, Size, &SectionData);
239 SD.setFragment(Fragment);
242 void MCWinCOFFStreamer::EmitZerofill(const MCSection *Section,
243 MCSymbol *Symbol, uint64_t Size,
244 unsigned ByteAlignment) {
245 llvm_unreachable("not implemented");
248 void MCWinCOFFStreamer::EmitTBSSSymbol(const MCSection *Section,
249 MCSymbol *Symbol, uint64_t Size,
250 unsigned ByteAlignment) {
251 llvm_unreachable("not implemented");
254 void MCWinCOFFStreamer::EmitFileDirective(StringRef Filename) {
255 getAssembler().addFileName(Filename);
258 // TODO: Implement this if you want to emit .comment section in COFF obj files.
259 void MCWinCOFFStreamer::EmitIdent(StringRef IdentString) {
260 llvm_unreachable("not implemented");
263 void MCWinCOFFStreamer::EmitWinEHHandlerData() {
264 llvm_unreachable("not implemented");
267 void MCWinCOFFStreamer::FinishImpl() {
268 MCObjectStreamer::FinishImpl();
271 LLVM_ATTRIBUTE_NORETURN
272 void MCWinCOFFStreamer::FatalError(const Twine &Msg) const {
273 getContext().FatalError(SMLoc(), Msg);