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 void MCObjectStreamer::reset() {
53 MCFragment *MCObjectStreamer::getCurrentFragment() const {
54 assert(getCurrentSectionData() && "No current section!");
56 if (!getCurrentSectionData()->empty())
57 return &getCurrentSectionData()->getFragmentList().back();
62 MCDataFragment *MCObjectStreamer::getOrCreateDataFragment() const {
63 MCDataFragment *F = dyn_cast_or_null<MCDataFragment>(getCurrentFragment());
65 F = new MCDataFragment(getCurrentSectionData());
69 const MCExpr *MCObjectStreamer::AddValueSymbols(const MCExpr *Value) {
70 switch (Value->getKind()) {
72 cast<MCTargetExpr>(Value)->AddValueSymbols(Assembler);
75 case MCExpr::Constant:
78 case MCExpr::Binary: {
79 const MCBinaryExpr *BE = cast<MCBinaryExpr>(Value);
80 AddValueSymbols(BE->getLHS());
81 AddValueSymbols(BE->getRHS());
85 case MCExpr::SymbolRef:
86 Assembler->getOrCreateSymbolData(cast<MCSymbolRefExpr>(Value)->getSymbol());
90 AddValueSymbols(cast<MCUnaryExpr>(Value)->getSubExpr());
97 void MCObjectStreamer::EmitValueImpl(const MCExpr *Value, unsigned Size,
99 assert(AddrSpace == 0 && "Address space must be 0!");
100 MCDataFragment *DF = getOrCreateDataFragment();
102 // Avoid fixups when possible.
104 if (AddValueSymbols(Value)->EvaluateAsAbsolute(AbsValue, getAssembler())) {
105 EmitIntValue(AbsValue, Size, AddrSpace);
108 DF->getFixups().push_back(
109 MCFixup::Create(DF->getContents().size(), Value,
110 MCFixup::getKindForSize(Size, false)));
111 DF->getContents().resize(DF->getContents().size() + Size, 0);
114 void MCObjectStreamer::EmitCFIStartProcImpl(MCDwarfFrameInfo &Frame) {
115 RecordProcStart(Frame);
118 void MCObjectStreamer::EmitCFIEndProcImpl(MCDwarfFrameInfo &Frame) {
119 RecordProcEnd(Frame);
122 void MCObjectStreamer::EmitLabel(MCSymbol *Symbol) {
123 MCStreamer::EmitLabel(Symbol);
125 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
127 // FIXME: This is wasteful, we don't necessarily need to create a data
128 // fragment. Instead, we should mark the symbol as pointing into the data
129 // fragment if it exists, otherwise we should just queue the label and set its
130 // fragment pointer when we emit the next fragment.
131 MCDataFragment *F = getOrCreateDataFragment();
132 assert(!SD.getFragment() && "Unexpected fragment on symbol data!");
134 SD.setOffset(F->getContents().size());
137 void MCObjectStreamer::EmitULEB128Value(const MCExpr *Value) {
139 if (Value->EvaluateAsAbsolute(IntValue, getAssembler())) {
140 EmitULEB128IntValue(IntValue);
143 Value = ForceExpAbs(Value);
144 new MCLEBFragment(*Value, false, getCurrentSectionData());
147 void MCObjectStreamer::EmitSLEB128Value(const MCExpr *Value) {
149 if (Value->EvaluateAsAbsolute(IntValue, getAssembler())) {
150 EmitSLEB128IntValue(IntValue);
153 Value = ForceExpAbs(Value);
154 new MCLEBFragment(*Value, true, getCurrentSectionData());
157 void MCObjectStreamer::EmitWeakReference(MCSymbol *Alias,
158 const MCSymbol *Symbol) {
159 report_fatal_error("This file format doesn't support weak aliases.");
162 void MCObjectStreamer::ChangeSection(const MCSection *Section) {
163 assert(Section && "Cannot switch to a null section!");
165 CurSectionData = &getAssembler().getOrCreateSectionData(*Section);
168 void MCObjectStreamer::EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) {
169 getAssembler().getOrCreateSymbolData(*Symbol);
170 Symbol->setVariableValue(AddValueSymbols(Value));
173 void MCObjectStreamer::EmitInstruction(const MCInst &Inst) {
175 for (unsigned i = Inst.getNumOperands(); i--; )
176 if (Inst.getOperand(i).isExpr())
177 AddValueSymbols(Inst.getOperand(i).getExpr());
179 getCurrentSectionData()->setHasInstructions(true);
181 // Now that a machine instruction has been assembled into this section, make
182 // a line entry for any .loc directive that has been seen.
183 MCLineEntry::Make(this, getCurrentSection());
185 // If this instruction doesn't need relaxation, just emit it as data.
186 if (!getAssembler().getBackend().mayNeedRelaxation(Inst)) {
187 EmitInstToData(Inst);
191 // Otherwise, if we are relaxing everything, relax the instruction as much as
192 // possible and emit it as data.
193 if (getAssembler().getRelaxAll()) {
195 getAssembler().getBackend().relaxInstruction(Inst, Relaxed);
196 while (getAssembler().getBackend().mayNeedRelaxation(Relaxed))
197 getAssembler().getBackend().relaxInstruction(Relaxed, Relaxed);
198 EmitInstToData(Relaxed);
202 // Otherwise emit to a separate fragment.
203 EmitInstToFragment(Inst);
206 void MCObjectStreamer::EmitInstToFragment(const MCInst &Inst) {
207 MCInstFragment *IF = new MCInstFragment(Inst, getCurrentSectionData());
209 SmallString<128> Code;
210 raw_svector_ostream VecOS(Code);
211 getAssembler().getEmitter().EncodeInstruction(Inst, VecOS, IF->getFixups());
213 IF->getContents().append(Code.begin(), Code.end());
216 void MCObjectStreamer::EmitDwarfAdvanceLineAddr(int64_t LineDelta,
217 const MCSymbol *LastLabel,
218 const MCSymbol *Label,
219 unsigned PointerSize) {
221 EmitDwarfSetLineAddr(LineDelta, Label, PointerSize);
224 const MCExpr *AddrDelta = BuildSymbolDiff(getContext(), Label, LastLabel);
226 if (AddrDelta->EvaluateAsAbsolute(Res, getAssembler())) {
227 MCDwarfLineAddr::Emit(this, LineDelta, Res);
230 AddrDelta = ForceExpAbs(AddrDelta);
231 new MCDwarfLineAddrFragment(LineDelta, *AddrDelta, getCurrentSectionData());
234 void MCObjectStreamer::EmitDwarfAdvanceFrameAddr(const MCSymbol *LastLabel,
235 const MCSymbol *Label) {
236 const MCExpr *AddrDelta = BuildSymbolDiff(getContext(), Label, LastLabel);
238 if (AddrDelta->EvaluateAsAbsolute(Res, getAssembler())) {
239 MCDwarfFrameEmitter::EmitAdvanceLoc(*this, Res);
242 AddrDelta = ForceExpAbs(AddrDelta);
243 new MCDwarfCallFrameFragment(*AddrDelta, getCurrentSectionData());
246 void MCObjectStreamer::EmitBytes(StringRef Data, unsigned AddrSpace) {
247 assert(AddrSpace == 0 && "Address space must be 0!");
248 getOrCreateDataFragment()->getContents().append(Data.begin(), Data.end());
251 void MCObjectStreamer::EmitValueToAlignment(unsigned ByteAlignment,
254 unsigned MaxBytesToEmit) {
255 if (MaxBytesToEmit == 0)
256 MaxBytesToEmit = ByteAlignment;
257 new MCAlignFragment(ByteAlignment, Value, ValueSize, MaxBytesToEmit,
258 getCurrentSectionData());
260 // Update the maximum alignment on the current section if necessary.
261 if (ByteAlignment > getCurrentSectionData()->getAlignment())
262 getCurrentSectionData()->setAlignment(ByteAlignment);
265 void MCObjectStreamer::EmitCodeAlignment(unsigned ByteAlignment,
266 unsigned MaxBytesToEmit) {
267 EmitValueToAlignment(ByteAlignment, 0, 1, MaxBytesToEmit);
268 cast<MCAlignFragment>(getCurrentFragment())->setEmitNops(true);
271 bool MCObjectStreamer::EmitValueToOffset(const MCExpr *Offset,
272 unsigned char Value) {
274 if (Offset->EvaluateAsAbsolute(Res, getAssembler())) {
275 new MCOrgFragment(*Offset, Value, getCurrentSectionData());
279 MCSymbol *CurrentPos = getContext().CreateTempSymbol();
280 EmitLabel(CurrentPos);
281 MCSymbolRefExpr::VariantKind Variant = MCSymbolRefExpr::VK_None;
283 MCSymbolRefExpr::Create(CurrentPos, Variant, getContext());
284 const MCExpr *Delta =
285 MCBinaryExpr::Create(MCBinaryExpr::Sub, Offset, Ref, getContext());
287 if (!Delta->EvaluateAsAbsolute(Res, getAssembler()))
289 EmitFill(Res, Value, 0);
293 // Associate GPRel32 fixup with data and resize data area
294 void MCObjectStreamer::EmitGPRel32Value(const MCExpr *Value) {
295 MCDataFragment *DF = getOrCreateDataFragment();
297 DF->getFixups().push_back(MCFixup::Create(DF->getContents().size(),
299 DF->getContents().resize(DF->getContents().size() + 4, 0);
302 // Associate GPRel32 fixup with data and resize data area
303 void MCObjectStreamer::EmitGPRel64Value(const MCExpr *Value) {
304 MCDataFragment *DF = getOrCreateDataFragment();
306 DF->getFixups().push_back(MCFixup::Create(DF->getContents().size(),
308 DF->getContents().resize(DF->getContents().size() + 8, 0);
311 void MCObjectStreamer::EmitFill(uint64_t NumBytes, uint8_t FillValue,
312 unsigned AddrSpace) {
313 assert(AddrSpace == 0 && "Address space must be 0!");
314 // FIXME: A MCFillFragment would be more memory efficient but MCExpr has
315 // problems evaluating expressions across multiple fragments.
316 getOrCreateDataFragment()->getContents().append(NumBytes, FillValue);
319 void MCObjectStreamer::FinishImpl() {
320 // Dump out the dwarf file & directory tables and line tables.
321 const MCSymbol *LineSectionSymbol = NULL;
322 if (getContext().hasDwarfFiles())
323 LineSectionSymbol = MCDwarfFileTable::Emit(this);
325 // If we are generating dwarf for assembly source files dump out the sections.
326 if (getContext().getGenDwarfForAssembly())
327 MCGenDwarfInfo::Emit(this, LineSectionSymbol);
329 getAssembler().Finish();