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::EmitDebugLabel(MCSymbol *Symbol) {
141 void MCObjectStreamer::EmitULEB128Value(const MCExpr *Value) {
143 if (Value->EvaluateAsAbsolute(IntValue, getAssembler())) {
144 EmitULEB128IntValue(IntValue);
147 Value = ForceExpAbs(Value);
148 new MCLEBFragment(*Value, false, getCurrentSectionData());
151 void MCObjectStreamer::EmitSLEB128Value(const MCExpr *Value) {
153 if (Value->EvaluateAsAbsolute(IntValue, getAssembler())) {
154 EmitSLEB128IntValue(IntValue);
157 Value = ForceExpAbs(Value);
158 new MCLEBFragment(*Value, true, getCurrentSectionData());
161 void MCObjectStreamer::EmitWeakReference(MCSymbol *Alias,
162 const MCSymbol *Symbol) {
163 report_fatal_error("This file format doesn't support weak aliases.");
166 void MCObjectStreamer::ChangeSection(const MCSection *Section) {
167 assert(Section && "Cannot switch to a null section!");
169 CurSectionData = &getAssembler().getOrCreateSectionData(*Section);
172 void MCObjectStreamer::EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) {
173 getAssembler().getOrCreateSymbolData(*Symbol);
174 Symbol->setVariableValue(AddValueSymbols(Value));
177 void MCObjectStreamer::EmitInstruction(const MCInst &Inst) {
179 for (unsigned i = Inst.getNumOperands(); i--; )
180 if (Inst.getOperand(i).isExpr())
181 AddValueSymbols(Inst.getOperand(i).getExpr());
183 getCurrentSectionData()->setHasInstructions(true);
185 // Now that a machine instruction has been assembled into this section, make
186 // a line entry for any .loc directive that has been seen.
187 MCLineEntry::Make(this, getCurrentSection());
189 // If this instruction doesn't need relaxation, just emit it as data.
190 if (!getAssembler().getBackend().mayNeedRelaxation(Inst)) {
191 EmitInstToData(Inst);
195 // Otherwise, if we are relaxing everything, relax the instruction as much as
196 // possible and emit it as data.
197 if (getAssembler().getRelaxAll()) {
199 getAssembler().getBackend().relaxInstruction(Inst, Relaxed);
200 while (getAssembler().getBackend().mayNeedRelaxation(Relaxed))
201 getAssembler().getBackend().relaxInstruction(Relaxed, Relaxed);
202 EmitInstToData(Relaxed);
206 // Otherwise emit to a separate fragment.
207 EmitInstToFragment(Inst);
210 void MCObjectStreamer::EmitInstToFragment(const MCInst &Inst) {
211 MCInstFragment *IF = new MCInstFragment(Inst, getCurrentSectionData());
213 SmallString<128> Code;
214 raw_svector_ostream VecOS(Code);
215 getAssembler().getEmitter().EncodeInstruction(Inst, VecOS, IF->getFixups());
217 IF->getContents().append(Code.begin(), Code.end());
220 void MCObjectStreamer::EmitDwarfAdvanceLineAddr(int64_t LineDelta,
221 const MCSymbol *LastLabel,
222 const MCSymbol *Label,
223 unsigned PointerSize) {
225 EmitDwarfSetLineAddr(LineDelta, Label, PointerSize);
228 const MCExpr *AddrDelta = BuildSymbolDiff(getContext(), Label, LastLabel);
230 if (AddrDelta->EvaluateAsAbsolute(Res, getAssembler())) {
231 MCDwarfLineAddr::Emit(this, LineDelta, Res);
234 AddrDelta = ForceExpAbs(AddrDelta);
235 new MCDwarfLineAddrFragment(LineDelta, *AddrDelta, getCurrentSectionData());
238 void MCObjectStreamer::EmitDwarfAdvanceFrameAddr(const MCSymbol *LastLabel,
239 const MCSymbol *Label) {
240 const MCExpr *AddrDelta = BuildSymbolDiff(getContext(), Label, LastLabel);
242 if (AddrDelta->EvaluateAsAbsolute(Res, getAssembler())) {
243 MCDwarfFrameEmitter::EmitAdvanceLoc(*this, Res);
246 AddrDelta = ForceExpAbs(AddrDelta);
247 new MCDwarfCallFrameFragment(*AddrDelta, getCurrentSectionData());
250 void MCObjectStreamer::EmitBytes(StringRef Data, unsigned AddrSpace) {
251 assert(AddrSpace == 0 && "Address space must be 0!");
252 getOrCreateDataFragment()->getContents().append(Data.begin(), Data.end());
255 void MCObjectStreamer::EmitValueToAlignment(unsigned ByteAlignment,
258 unsigned MaxBytesToEmit) {
259 if (MaxBytesToEmit == 0)
260 MaxBytesToEmit = ByteAlignment;
261 new MCAlignFragment(ByteAlignment, Value, ValueSize, MaxBytesToEmit,
262 getCurrentSectionData());
264 // Update the maximum alignment on the current section if necessary.
265 if (ByteAlignment > getCurrentSectionData()->getAlignment())
266 getCurrentSectionData()->setAlignment(ByteAlignment);
269 void MCObjectStreamer::EmitCodeAlignment(unsigned ByteAlignment,
270 unsigned MaxBytesToEmit) {
271 EmitValueToAlignment(ByteAlignment, 0, 1, MaxBytesToEmit);
272 cast<MCAlignFragment>(getCurrentFragment())->setEmitNops(true);
275 bool MCObjectStreamer::EmitValueToOffset(const MCExpr *Offset,
276 unsigned char Value) {
278 if (Offset->EvaluateAsAbsolute(Res, getAssembler())) {
279 new MCOrgFragment(*Offset, Value, getCurrentSectionData());
283 MCSymbol *CurrentPos = getContext().CreateTempSymbol();
284 EmitLabel(CurrentPos);
285 MCSymbolRefExpr::VariantKind Variant = MCSymbolRefExpr::VK_None;
287 MCSymbolRefExpr::Create(CurrentPos, Variant, getContext());
288 const MCExpr *Delta =
289 MCBinaryExpr::Create(MCBinaryExpr::Sub, Offset, Ref, getContext());
291 if (!Delta->EvaluateAsAbsolute(Res, getAssembler()))
293 EmitFill(Res, Value, 0);
297 // Associate GPRel32 fixup with data and resize data area
298 void MCObjectStreamer::EmitGPRel32Value(const MCExpr *Value) {
299 MCDataFragment *DF = getOrCreateDataFragment();
301 DF->getFixups().push_back(MCFixup::Create(DF->getContents().size(),
303 DF->getContents().resize(DF->getContents().size() + 4, 0);
306 // Associate GPRel32 fixup with data and resize data area
307 void MCObjectStreamer::EmitGPRel64Value(const MCExpr *Value) {
308 MCDataFragment *DF = getOrCreateDataFragment();
310 DF->getFixups().push_back(MCFixup::Create(DF->getContents().size(),
312 DF->getContents().resize(DF->getContents().size() + 8, 0);
315 void MCObjectStreamer::EmitFill(uint64_t NumBytes, uint8_t FillValue,
316 unsigned AddrSpace) {
317 assert(AddrSpace == 0 && "Address space must be 0!");
318 // FIXME: A MCFillFragment would be more memory efficient but MCExpr has
319 // problems evaluating expressions across multiple fragments.
320 getOrCreateDataFragment()->getContents().append(NumBytes, FillValue);
323 void MCObjectStreamer::FinishImpl() {
324 // Dump out the dwarf file & directory tables and line tables.
325 const MCSymbol *LineSectionSymbol = NULL;
326 if (getContext().hasDwarfFiles())
327 LineSectionSymbol = MCDwarfFileTable::Emit(this);
329 // If we are generating dwarf for assembly source files dump out the sections.
330 if (getContext().getGenDwarfForAssembly())
331 MCGenDwarfInfo::Emit(this, LineSectionSymbol);
333 getAssembler().Finish();