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
36using namespace llvm;
37
38#define DEBUG_TYPE "WinCOFFStreamer"
39
40namespace llvm {
41MCWinCOFFStreamer::MCWinCOFFStreamer(MCContext &Context, MCAsmBackend &MAB,
42                                     MCCodeEmitter &CE, raw_ostream &OS)
43    : MCObjectStreamer(Context, MAB, OS, &CE), CurSymbol(nullptr) {}
44
45void 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
64void 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
80void MCWinCOFFStreamer::EmitLabel(MCSymbol *Symbol) {
81  assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
82  MCObjectStreamer::EmitLabel(Symbol);
83}
84
85void MCWinCOFFStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) {
86  llvm_unreachable("not implemented");
87}
88
89void MCWinCOFFStreamer::EmitThumbFunc(MCSymbol *Func) {
90  llvm_unreachable("not implemented");
91}
92
93bool 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
117void MCWinCOFFStreamer::EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {
118  llvm_unreachable("not implemented");
119}
120
121void 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
132void 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
144void 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
155void MCWinCOFFStreamer::EndCOFFSymbolDef() {
156  if (!CurSymbol)
157    FatalError("ending symbol definition without starting one");
158  CurSymbol = nullptr;
159}
160
161void 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
169void 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
177void MCWinCOFFStreamer::EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) {
178  llvm_unreachable("not supported");
179}
180
181void 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
197void 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
220void MCWinCOFFStreamer::EmitZerofill(const MCSection *Section,
221                                     MCSymbol *Symbol, uint64_t Size,
222                                     unsigned ByteAlignment) {
223  llvm_unreachable("not implemented");
224}
225
226void MCWinCOFFStreamer::EmitTBSSSymbol(const MCSection *Section,
227                                       MCSymbol *Symbol, uint64_t Size,
228                                       unsigned ByteAlignment) {
229  llvm_unreachable("not implemented");
230}
231
232void 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.
237void MCWinCOFFStreamer::EmitIdent(StringRef IdentString) {
238  llvm_unreachable("not implemented");
239}
240
241void MCWinCOFFStreamer::EmitWinEHHandlerData() {
242  llvm_unreachable("not implemented");
243}
244
245void MCWinCOFFStreamer::FinishImpl() {
246  MCObjectStreamer::FinishImpl();
247}
248
249LLVM_ATTRIBUTE_NORETURN
250void MCWinCOFFStreamer::FatalError(const Twine &Msg) const {
251  getContext().FatalError(SMLoc(), Msg);
252}
253}
254
255