1 //===-- llvm/MC/WinCOFFStreamer.cpp -----------------------------*- C++ -*-===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file contains an implementation of a Windows COFF object file streamer.
11 //
12 //===----------------------------------------------------------------------===//
13
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/MCWin64EH.h"
29 #include "llvm/MC/MCWinCOFFStreamer.h"
30 #include "llvm/Support/COFF.h"
31 #include "llvm/Support/Debug.h"
32 #include "llvm/Support/ErrorHandling.h"
33 #include "llvm/Support/TargetRegistry.h"
34 #include "llvm/Support/raw_ostream.h"
35
36 using namespace llvm;
37
38 #define DEBUG_TYPE "WinCOFFStreamer"
39
40 namespace llvm {
MCWinCOFFStreamer(MCContext & Context,MCAsmBackend & MAB,MCCodeEmitter & CE,raw_ostream & OS)41 MCWinCOFFStreamer::MCWinCOFFStreamer(MCContext &Context, MCAsmBackend &MAB,
42 MCCodeEmitter &CE, raw_ostream &OS)
43 : MCObjectStreamer(Context, MAB, OS, &CE), CurSymbol(nullptr) {}
44
EmitInstToData(const MCInst & Inst,const MCSubtargetInfo & STI)45 void MCWinCOFFStreamer::EmitInstToData(const MCInst &Inst,
46 const MCSubtargetInfo &STI) {
47 MCDataFragment *DF = getOrCreateDataFragment();
48
49 SmallVector<MCFixup, 4> Fixups;
50 SmallString<256> Code;
51 raw_svector_ostream VecOS(Code);
52 getAssembler().getEmitter().EncodeInstruction(Inst, VecOS, Fixups, STI);
53 VecOS.flush();
54
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]);
59 }
60
61 DF->getContents().append(Code.begin(), Code.end());
62 }
63
InitSections()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());
69 EmitCodeAlignment(4);
70
71 SwitchSection(getContext().getObjectFileInfo()->getDataSection());
72 EmitCodeAlignment(4);
73
74 SwitchSection(getContext().getObjectFileInfo()->getBSSSection());
75 EmitCodeAlignment(4);
76
77 SwitchSection(getContext().getObjectFileInfo()->getTextSection());
78 }
79
EmitLabel(MCSymbol * Symbol)80 void MCWinCOFFStreamer::EmitLabel(MCSymbol *Symbol) {
81 assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
82 MCObjectStreamer::EmitLabel(Symbol);
83 }
84
EmitAssemblerFlag(MCAssemblerFlag Flag)85 void MCWinCOFFStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) {
86 llvm_unreachable("not implemented");
87 }
88
EmitThumbFunc(MCSymbol * Func)89 void MCWinCOFFStreamer::EmitThumbFunc(MCSymbol *Func) {
90 llvm_unreachable("not implemented");
91 }
92
EmitSymbolAttribute(MCSymbol * Symbol,MCSymbolAttr Attribute)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!");
99
100 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
101
102 switch (Attribute) {
103 default: return false;
104 case MCSA_WeakReference:
105 case MCSA_Weak:
106 SD.modifyFlags(COFF::SF_WeakExternal, COFF::SF_WeakExternal);
107 SD.setExternal(true);
108 break;
109 case MCSA_Global:
110 SD.setExternal(true);
111 break;
112 }
113
114 return true;
115 }
116
EmitSymbolDesc(MCSymbol * Symbol,unsigned DescValue)117 void MCWinCOFFStreamer::EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {
118 llvm_unreachable("not implemented");
119 }
120
BeginCOFFSymbolDef(MCSymbol const * Symbol)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!");
125
126 if (CurSymbol)
127 FatalError("starting a new symbol definition without completing the "
128 "previous one");
129 CurSymbol = Symbol;
130 }
131
EmitCOFFSymbolStorageClass(int StorageClass)132 void MCWinCOFFStreamer::EmitCOFFSymbolStorageClass(int StorageClass) {
133 if (!CurSymbol)
134 FatalError("storage class specified outside of symbol definition");
135
136 if (StorageClass & ~0xff)
137 FatalError(Twine("storage class value '") + itostr(StorageClass) +
138 "' out of range");
139
140 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*CurSymbol);
141 SD.modifyFlags(StorageClass << COFF::SF_ClassShift, COFF::SF_ClassMask);
142 }
143
EmitCOFFSymbolType(int Type)144 void MCWinCOFFStreamer::EmitCOFFSymbolType(int Type) {
145 if (!CurSymbol)
146 FatalError("symbol type specified outside of a symbol definition");
147
148 if (Type & ~0xffff)
149 FatalError(Twine("type value '") + itostr(Type) + "' out of range");
150
151 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*CurSymbol);
152 SD.modifyFlags(Type << COFF::SF_TypeShift, COFF::SF_TypeMask);
153 }
154
EndCOFFSymbolDef()155 void MCWinCOFFStreamer::EndCOFFSymbolDef() {
156 if (!CurSymbol)
157 FatalError("ending symbol definition without starting one");
158 CurSymbol = nullptr;
159 }
160
EmitCOFFSectionIndex(MCSymbol const * Symbol)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);
167 }
168
EmitCOFFSecRel32(MCSymbol const * Symbol)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);
175 }
176
EmitELFSize(MCSymbol * Symbol,const MCExpr * Value)177 void MCWinCOFFStreamer::EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) {
178 llvm_unreachable("not supported");
179 }
180
EmitCommonSymbol(MCSymbol * Symbol,uint64_t Size,unsigned ByteAlignment)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!");
186
187 if (ByteAlignment > 32)
188 report_fatal_error("alignment is limited to 32-bytes");
189
190 AssignSection(Symbol, nullptr);
191
192 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
193 SD.setExternal(true);
194 SD.setCommon(Size, ByteAlignment);
195 }
196
EmitLocalCommonSymbol(MCSymbol * Symbol,uint64_t Size,unsigned ByteAlignment)197 void MCWinCOFFStreamer::EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
198 unsigned ByteAlignment) {
199 assert(!Symbol->isInSection() && "Symbol must not already have a section!");
200
201 const MCSection *Section = getContext().getObjectFileInfo()->getBSSSection();
202 MCSectionData &SectionData = getAssembler().getOrCreateSectionData(*Section);
203 if (SectionData.getAlignment() < ByteAlignment)
204 SectionData.setAlignment(ByteAlignment);
205
206 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
207 SD.setExternal(false);
208
209 AssignSection(Symbol, Section);
210
211 if (ByteAlignment != 1)
212 new MCAlignFragment(ByteAlignment, /*_Value=*/0, /*_ValueSize=*/0,
213 ByteAlignment, &SectionData);
214
215 MCFillFragment *Fragment =
216 new MCFillFragment(/*_Value=*/0, /*_ValueSize=*/0, Size, &SectionData);
217 SD.setFragment(Fragment);
218 }
219
EmitZerofill(const MCSection * Section,MCSymbol * Symbol,uint64_t Size,unsigned ByteAlignment)220 void MCWinCOFFStreamer::EmitZerofill(const MCSection *Section,
221 MCSymbol *Symbol, uint64_t Size,
222 unsigned ByteAlignment) {
223 llvm_unreachable("not implemented");
224 }
225
EmitTBSSSymbol(const MCSection * Section,MCSymbol * Symbol,uint64_t Size,unsigned ByteAlignment)226 void MCWinCOFFStreamer::EmitTBSSSymbol(const MCSection *Section,
227 MCSymbol *Symbol, uint64_t Size,
228 unsigned ByteAlignment) {
229 llvm_unreachable("not implemented");
230 }
231
EmitFileDirective(StringRef Filename)232 void MCWinCOFFStreamer::EmitFileDirective(StringRef Filename) {
233 getAssembler().addFileName(Filename);
234 }
235
236 // TODO: Implement this if you want to emit .comment section in COFF obj files.
EmitIdent(StringRef IdentString)237 void MCWinCOFFStreamer::EmitIdent(StringRef IdentString) {
238 llvm_unreachable("not implemented");
239 }
240
EmitWinEHHandlerData()241 void MCWinCOFFStreamer::EmitWinEHHandlerData() {
242 llvm_unreachable("not implemented");
243 }
244
FinishImpl()245 void MCWinCOFFStreamer::FinishImpl() {
246 MCObjectStreamer::FinishImpl();
247 }
248
249 LLVM_ATTRIBUTE_NORETURN
FatalError(const Twine & Msg) const250 void MCWinCOFFStreamer::FatalError(const Twine &Msg) const {
251 getContext().FatalError(SMLoc(), Msg);
252 }
253 }
254
255