1 //===- lib/MC/MCObjectStreamer.cpp - Object File MCStreamer Interface -----===//
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 #include "llvm/MC/MCObjectStreamer.h"
11 #include "llvm/MC/MCAsmBackend.h"
12 #include "llvm/MC/MCAsmInfo.h"
13 #include "llvm/MC/MCAssembler.h"
14 #include "llvm/MC/MCCodeEmitter.h"
15 #include "llvm/MC/MCContext.h"
16 #include "llvm/MC/MCDwarf.h"
17 #include "llvm/MC/MCExpr.h"
18 #include "llvm/MC/MCObjectWriter.h"
19 #include "llvm/MC/MCSymbol.h"
20 #include "llvm/Support/ErrorHandling.h"
23 MCObjectStreamer::MCObjectStreamer(MCContext &Context, MCAsmBackend &TAB,
24 raw_ostream &OS, MCCodeEmitter *Emitter_)
25 : MCStreamer(Context),
26 Assembler(new MCAssembler(Context, TAB,
27 *Emitter_, *TAB.createObjectWriter(OS),
33 MCObjectStreamer::MCObjectStreamer(MCContext &Context, MCAsmBackend &TAB,
34 raw_ostream &OS, MCCodeEmitter *Emitter_,
35 MCAssembler *_Assembler)
36 : MCStreamer(Context), Assembler(_Assembler), CurSectionData(0)
40 MCObjectStreamer::~MCObjectStreamer() {
41 delete &Assembler->getBackend();
42 delete &Assembler->getEmitter();
43 delete &Assembler->getWriter();
47 MCFragment *MCObjectStreamer::getCurrentFragment() const {
48 assert(getCurrentSectionData() && "No current section!");
50 if (!getCurrentSectionData()->empty())
51 return &getCurrentSectionData()->getFragmentList().back();
56 MCDataFragment *MCObjectStreamer::getOrCreateDataFragment() const {
57 MCDataFragment *F = dyn_cast_or_null<MCDataFragment>(getCurrentFragment());
59 F = new MCDataFragment(getCurrentSectionData());
63 const MCExpr *MCObjectStreamer::AddValueSymbols(const MCExpr *Value) {
64 switch (Value->getKind()) {
66 cast<MCTargetExpr>(Value)->AddValueSymbols(Assembler);
69 case MCExpr::Constant:
72 case MCExpr::Binary: {
73 const MCBinaryExpr *BE = cast<MCBinaryExpr>(Value);
74 AddValueSymbols(BE->getLHS());
75 AddValueSymbols(BE->getRHS());
79 case MCExpr::SymbolRef:
80 Assembler->getOrCreateSymbolData(cast<MCSymbolRefExpr>(Value)->getSymbol());
84 AddValueSymbols(cast<MCUnaryExpr>(Value)->getSubExpr());
91 void MCObjectStreamer::EmitValueImpl(const MCExpr *Value, unsigned Size,
93 assert(AddrSpace == 0 && "Address space must be 0!");
94 MCDataFragment *DF = getOrCreateDataFragment();
96 // Avoid fixups when possible.
98 if (AddValueSymbols(Value)->EvaluateAsAbsolute(AbsValue, getAssembler())) {
99 EmitIntValue(AbsValue, Size, AddrSpace);
102 DF->addFixup(MCFixup::Create(DF->getContents().size(),
104 MCFixup::getKindForSize(Size, false)));
105 DF->getContents().resize(DF->getContents().size() + Size, 0);
108 void MCObjectStreamer::EmitCFIStartProcImpl(MCDwarfFrameInfo &Frame) {
109 RecordProcStart(Frame);
112 void MCObjectStreamer::EmitCFIEndProcImpl(MCDwarfFrameInfo &Frame) {
113 RecordProcEnd(Frame);
116 void MCObjectStreamer::EmitLabel(MCSymbol *Symbol) {
117 MCStreamer::EmitLabel(Symbol);
119 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
121 // FIXME: This is wasteful, we don't necessarily need to create a data
122 // fragment. Instead, we should mark the symbol as pointing into the data
123 // fragment if it exists, otherwise we should just queue the label and set its
124 // fragment pointer when we emit the next fragment.
125 MCDataFragment *F = getOrCreateDataFragment();
126 assert(!SD.getFragment() && "Unexpected fragment on symbol data!");
128 SD.setOffset(F->getContents().size());
131 void MCObjectStreamer::EmitULEB128Value(const MCExpr *Value) {
133 if (Value->EvaluateAsAbsolute(IntValue, getAssembler())) {
134 EmitULEB128IntValue(IntValue);
137 Value = ForceExpAbs(Value);
138 new MCLEBFragment(*Value, false, getCurrentSectionData());
141 void MCObjectStreamer::EmitSLEB128Value(const MCExpr *Value) {
143 if (Value->EvaluateAsAbsolute(IntValue, getAssembler())) {
144 EmitSLEB128IntValue(IntValue);
147 Value = ForceExpAbs(Value);
148 new MCLEBFragment(*Value, true, getCurrentSectionData());
151 void MCObjectStreamer::EmitWeakReference(MCSymbol *Alias,
152 const MCSymbol *Symbol) {
153 report_fatal_error("This file format doesn't support weak aliases.");
156 void MCObjectStreamer::ChangeSection(const MCSection *Section) {
157 assert(Section && "Cannot switch to a null section!");
159 CurSectionData = &getAssembler().getOrCreateSectionData(*Section);
162 void MCObjectStreamer::EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) {
163 getAssembler().getOrCreateSymbolData(*Symbol);
164 Symbol->setVariableValue(AddValueSymbols(Value));
167 void MCObjectStreamer::EmitInstruction(const MCInst &Inst) {
169 for (unsigned i = Inst.getNumOperands(); i--; )
170 if (Inst.getOperand(i).isExpr())
171 AddValueSymbols(Inst.getOperand(i).getExpr());
173 getCurrentSectionData()->setHasInstructions(true);
175 // Now that a machine instruction has been assembled into this section, make
176 // a line entry for any .loc directive that has been seen.
177 MCLineEntry::Make(this, getCurrentSection());
179 // If this instruction doesn't need relaxation, just emit it as data.
180 if (!getAssembler().getBackend().mayNeedRelaxation(Inst)) {
181 EmitInstToData(Inst);
185 // Otherwise, if we are relaxing everything, relax the instruction as much as
186 // possible and emit it as data.
187 if (getAssembler().getRelaxAll()) {
189 getAssembler().getBackend().relaxInstruction(Inst, Relaxed);
190 while (getAssembler().getBackend().mayNeedRelaxation(Relaxed))
191 getAssembler().getBackend().relaxInstruction(Relaxed, Relaxed);
192 EmitInstToData(Relaxed);
196 // Otherwise emit to a separate fragment.
197 EmitInstToFragment(Inst);
200 void MCObjectStreamer::EmitInstToFragment(const MCInst &Inst) {
201 MCInstFragment *IF = new MCInstFragment(Inst, getCurrentSectionData());
203 SmallString<128> Code;
204 raw_svector_ostream VecOS(Code);
205 getAssembler().getEmitter().EncodeInstruction(Inst, VecOS, IF->getFixups());
207 IF->getCode().append(Code.begin(), Code.end());
210 void MCObjectStreamer::EmitDwarfAdvanceLineAddr(int64_t LineDelta,
211 const MCSymbol *LastLabel,
212 const MCSymbol *Label,
213 unsigned PointerSize) {
215 EmitDwarfSetLineAddr(LineDelta, Label, PointerSize);
218 const MCExpr *AddrDelta = BuildSymbolDiff(getContext(), Label, LastLabel);
220 if (AddrDelta->EvaluateAsAbsolute(Res, getAssembler())) {
221 MCDwarfLineAddr::Emit(this, LineDelta, Res);
224 AddrDelta = ForceExpAbs(AddrDelta);
225 new MCDwarfLineAddrFragment(LineDelta, *AddrDelta, getCurrentSectionData());
228 void MCObjectStreamer::EmitDwarfAdvanceFrameAddr(const MCSymbol *LastLabel,
229 const MCSymbol *Label) {
230 const MCExpr *AddrDelta = BuildSymbolDiff(getContext(), Label, LastLabel);
232 if (AddrDelta->EvaluateAsAbsolute(Res, getAssembler())) {
233 MCDwarfFrameEmitter::EmitAdvanceLoc(*this, Res);
236 AddrDelta = ForceExpAbs(AddrDelta);
237 new MCDwarfCallFrameFragment(*AddrDelta, getCurrentSectionData());
240 void MCObjectStreamer::EmitBytes(StringRef Data, unsigned AddrSpace) {
241 assert(AddrSpace == 0 && "Address space must be 0!");
242 getOrCreateDataFragment()->getContents().append(Data.begin(), Data.end());
245 void MCObjectStreamer::EmitValueToAlignment(unsigned ByteAlignment,
248 unsigned MaxBytesToEmit) {
249 if (MaxBytesToEmit == 0)
250 MaxBytesToEmit = ByteAlignment;
251 new MCAlignFragment(ByteAlignment, Value, ValueSize, MaxBytesToEmit,
252 getCurrentSectionData());
254 // Update the maximum alignment on the current section if necessary.
255 if (ByteAlignment > getCurrentSectionData()->getAlignment())
256 getCurrentSectionData()->setAlignment(ByteAlignment);
259 void MCObjectStreamer::EmitCodeAlignment(unsigned ByteAlignment,
260 unsigned MaxBytesToEmit) {
261 EmitValueToAlignment(ByteAlignment, 0, 1, MaxBytesToEmit);
262 cast<MCAlignFragment>(getCurrentFragment())->setEmitNops(true);
265 bool MCObjectStreamer::EmitValueToOffset(const MCExpr *Offset,
266 unsigned char Value) {
268 if (Offset->EvaluateAsAbsolute(Res, getAssembler())) {
269 new MCOrgFragment(*Offset, Value, getCurrentSectionData());
273 MCSymbol *CurrentPos = getContext().CreateTempSymbol();
274 EmitLabel(CurrentPos);
275 MCSymbolRefExpr::VariantKind Variant = MCSymbolRefExpr::VK_None;
277 MCSymbolRefExpr::Create(CurrentPos, Variant, getContext());
278 const MCExpr *Delta =
279 MCBinaryExpr::Create(MCBinaryExpr::Sub, Offset, Ref, getContext());
281 if (!Delta->EvaluateAsAbsolute(Res, getAssembler()))
283 EmitFill(Res, Value, 0);
287 // Associate GPRel32 fixup with data and resize data area
288 void MCObjectStreamer::EmitGPRel32Value(const MCExpr *Value) {
289 MCDataFragment *DF = getOrCreateDataFragment();
291 DF->addFixup(MCFixup::Create(DF->getContents().size(), Value, FK_GPRel_4));
292 DF->getContents().resize(DF->getContents().size() + 4, 0);
295 // Associate GPRel32 fixup with data and resize data area
296 void MCObjectStreamer::EmitGPRel64Value(const MCExpr *Value) {
297 MCDataFragment *DF = getOrCreateDataFragment();
299 DF->addFixup(MCFixup::Create(DF->getContents().size(), Value, FK_GPRel_4));
300 DF->getContents().resize(DF->getContents().size() + 8, 0);
303 void MCObjectStreamer::EmitFill(uint64_t NumBytes, uint8_t FillValue,
304 unsigned AddrSpace) {
305 assert(AddrSpace == 0 && "Address space must be 0!");
306 // FIXME: A MCFillFragment would be more memory efficient but MCExpr has
307 // problems evaluating expressions across multiple fragments.
308 getOrCreateDataFragment()->getContents().append(NumBytes, FillValue);
311 void MCObjectStreamer::FinishImpl() {
312 // Dump out the dwarf file & directory tables and line tables.
313 const MCSymbol *LineSectionSymbol = NULL;
314 if (getContext().hasDwarfFiles())
315 LineSectionSymbol = MCDwarfFileTable::Emit(this);
317 // If we are generating dwarf for assembly source files dump out the sections.
318 if (getContext().getGenDwarfForAssembly())
319 MCGenDwarfInfo::Emit(this, LineSectionSymbol);
321 getAssembler().Finish();