1//===- lib/MC/MCPureStreamer.cpp - MC "Pure" Object Output ----------------===//
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#include "llvm/MC/MCStreamer.h"
11#include "llvm/MC/MCAssembler.h"
12#include "llvm/MC/MCCodeEmitter.h"
13#include "llvm/MC/MCContext.h"
14#include "llvm/MC/MCExpr.h"
15#include "llvm/MC/MCObjectFileInfo.h"
16#include "llvm/MC/MCObjectStreamer.h"
17#include "llvm/MC/MCSymbol.h"
18#include "llvm/Support/ErrorHandling.h"
19
20using namespace llvm;
21
22namespace {
23
24class MCPureStreamer : public MCObjectStreamer {
25private:
26  virtual void EmitInstToFragment(const MCInst &Inst);
27  virtual void EmitInstToData(const MCInst &Inst);
28
29public:
30  MCPureStreamer(MCContext &Context, MCAsmBackend &TAB, raw_ostream &OS,
31                 MCCodeEmitter *Emitter)
32      : MCObjectStreamer(Context, 0, TAB, OS, Emitter) {}
33
34  /// @name MCStreamer Interface
35  /// @{
36
37  virtual void InitSections();
38  virtual void InitToTextSection();
39  virtual void EmitLabel(MCSymbol *Symbol);
40  virtual void EmitDebugLabel(MCSymbol *Symbol);
41  virtual void EmitZerofill(const MCSection *Section, MCSymbol *Symbol = 0,
42                            uint64_t Size = 0, unsigned ByteAlignment = 0);
43  virtual void EmitBytes(StringRef Data);
44  virtual void EmitValueToAlignment(unsigned ByteAlignment, int64_t Value = 0,
45                                    unsigned ValueSize = 1,
46                                    unsigned MaxBytesToEmit = 0);
47  virtual void EmitCodeAlignment(unsigned ByteAlignment,
48                                 unsigned MaxBytesToEmit = 0);
49  virtual bool EmitValueToOffset(const MCExpr *Offset,
50                                 unsigned char Value = 0);
51  virtual void FinishImpl();
52
53
54  virtual bool EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute) {
55    report_fatal_error("unsupported directive in pure streamer");
56    return false;
57  }
58  virtual void EmitAssemblerFlag(MCAssemblerFlag Flag) {
59    report_fatal_error("unsupported directive in pure streamer");
60  }
61  virtual void EmitTBSSSymbol(const MCSection *Section, MCSymbol *Symbol,
62                              uint64_t Size, unsigned ByteAlignment = 0) {
63    report_fatal_error("unsupported directive in pure streamer");
64  }
65  virtual void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {
66    report_fatal_error("unsupported directive in pure streamer");
67  }
68  virtual void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
69                                unsigned ByteAlignment) {
70    report_fatal_error("unsupported directive in pure streamer");
71  }
72  virtual void EmitThumbFunc(MCSymbol *Func) {
73    report_fatal_error("unsupported directive in pure streamer");
74  }
75  virtual void BeginCOFFSymbolDef(const MCSymbol *Symbol) {
76    report_fatal_error("unsupported directive in pure streamer");
77  }
78  virtual void EmitCOFFSymbolStorageClass(int StorageClass) {
79    report_fatal_error("unsupported directive in pure streamer");
80  }
81  virtual void EmitCOFFSymbolType(int Type) {
82    report_fatal_error("unsupported directive in pure streamer");
83  }
84  virtual void EndCOFFSymbolDef() {
85    report_fatal_error("unsupported directive in pure streamer");
86  }
87  virtual void EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) {
88    report_fatal_error("unsupported directive in pure streamer");
89  }
90  virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
91                                     unsigned ByteAlignment) {
92    report_fatal_error("unsupported directive in pure streamer");
93  }
94  virtual void EmitFileDirective(StringRef Filename) {
95    report_fatal_error("unsupported directive in pure streamer");
96  }
97  virtual void EmitIdent(StringRef IdentString) {
98    report_fatal_error("unsupported directive in pure streamer");
99  }
100  virtual bool EmitDwarfFileDirective(unsigned FileNo, StringRef Directory,
101                                      StringRef Filename, unsigned CUID = 0) {
102    report_fatal_error("unsupported directive in pure streamer");
103  }
104};
105
106} // end anonymous namespace.
107
108void MCPureStreamer::InitSections() {
109  InitToTextSection();
110}
111
112void MCPureStreamer::InitToTextSection() {
113  SwitchSection(getContext().getObjectFileInfo()->getTextSection());
114}
115
116void MCPureStreamer::EmitLabel(MCSymbol *Symbol) {
117  assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
118  assert(!Symbol->isVariable() && "Cannot emit a variable symbol!");
119  assert(getCurrentSection().first && "Cannot emit before setting section!");
120
121  AssignSection(Symbol, getCurrentSection().first);
122
123  MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
124
125  // We have to create a new fragment if this is an atom defining symbol,
126  // fragments cannot span atoms.
127  if (getAssembler().isSymbolLinkerVisible(SD.getSymbol()))
128    insert(new MCDataFragment());
129
130  // FIXME: This is wasteful, we don't necessarily need to create a data
131  // fragment. Instead, we should mark the symbol as pointing into the data
132  // fragment if it exists, otherwise we should just queue the label and set its
133  // fragment pointer when we emit the next fragment.
134  MCDataFragment *F = getOrCreateDataFragment();
135  assert(!SD.getFragment() && "Unexpected fragment on symbol data!");
136  SD.setFragment(F);
137  SD.setOffset(F->getContents().size());
138}
139
140
141void MCPureStreamer::EmitDebugLabel(MCSymbol *Symbol) {
142  EmitLabel(Symbol);
143}
144
145void MCPureStreamer::EmitZerofill(const MCSection *Section, MCSymbol *Symbol,
146                                  uint64_t Size, unsigned ByteAlignment) {
147  report_fatal_error("not yet implemented in pure streamer");
148}
149
150void MCPureStreamer::EmitBytes(StringRef Data) {
151  // TODO: This is exactly the same as WinCOFFStreamer. Consider merging into
152  // MCObjectStreamer.
153  getOrCreateDataFragment()->getContents().append(Data.begin(), Data.end());
154}
155
156void MCPureStreamer::EmitValueToAlignment(unsigned ByteAlignment,
157                                          int64_t Value, unsigned ValueSize,
158                                          unsigned MaxBytesToEmit) {
159  // TODO: This is exactly the same as WinCOFFStreamer. Consider merging into
160  // MCObjectStreamer.
161  if (MaxBytesToEmit == 0)
162    MaxBytesToEmit = ByteAlignment;
163  insert(new MCAlignFragment(ByteAlignment, Value, ValueSize, MaxBytesToEmit));
164
165  // Update the maximum alignment on the current section if necessary.
166  if (ByteAlignment > getCurrentSectionData()->getAlignment())
167    getCurrentSectionData()->setAlignment(ByteAlignment);
168}
169
170void MCPureStreamer::EmitCodeAlignment(unsigned ByteAlignment,
171                                       unsigned MaxBytesToEmit) {
172  // TODO: This is exactly the same as WinCOFFStreamer. Consider merging into
173  // MCObjectStreamer.
174  if (MaxBytesToEmit == 0)
175    MaxBytesToEmit = ByteAlignment;
176  MCAlignFragment *F = new MCAlignFragment(ByteAlignment, 0, 1, MaxBytesToEmit);
177  insert(F);
178  F->setEmitNops(true);
179
180  // Update the maximum alignment on the current section if necessary.
181  if (ByteAlignment > getCurrentSectionData()->getAlignment())
182    getCurrentSectionData()->setAlignment(ByteAlignment);
183}
184
185bool MCPureStreamer::EmitValueToOffset(const MCExpr *Offset,
186                                       unsigned char Value) {
187  insert(new MCOrgFragment(*Offset, Value));
188  return false;
189}
190
191void MCPureStreamer::EmitInstToFragment(const MCInst &Inst) {
192  MCRelaxableFragment *IF = new MCRelaxableFragment(Inst);
193  insert(IF);
194
195  // Add the fixups and data.
196  //
197  // FIXME: Revisit this design decision when relaxation is done, we may be
198  // able to get away with not storing any extra data in the MCInst.
199  SmallVector<MCFixup, 4> Fixups;
200  SmallString<256> Code;
201  raw_svector_ostream VecOS(Code);
202  getAssembler().getEmitter().EncodeInstruction(Inst, VecOS, Fixups);
203  VecOS.flush();
204
205  IF->getContents() = Code;
206  IF->getFixups() = Fixups;
207}
208
209void MCPureStreamer::EmitInstToData(const MCInst &Inst) {
210  MCDataFragment *DF = getOrCreateDataFragment();
211
212  SmallVector<MCFixup, 4> Fixups;
213  SmallString<256> Code;
214  raw_svector_ostream VecOS(Code);
215  getAssembler().getEmitter().EncodeInstruction(Inst, VecOS, Fixups);
216  VecOS.flush();
217
218  // Add the fixups and data.
219  for (unsigned i = 0, e = Fixups.size(); i != e; ++i) {
220    Fixups[i].setOffset(Fixups[i].getOffset() + DF->getContents().size());
221    DF->getFixups().push_back(Fixups[i]);
222  }
223  DF->getContents().append(Code.begin(), Code.end());
224}
225
226void MCPureStreamer::FinishImpl() {
227  // FIXME: Handle DWARF tables?
228
229  this->MCObjectStreamer::FinishImpl();
230}
231
232MCStreamer *llvm::createPureStreamer(MCContext &Context, MCAsmBackend &MAB,
233                                     raw_ostream &OS, MCCodeEmitter *CE) {
234  return new MCPureStreamer(Context, MAB, OS, CE);
235}
236