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() {
52 MCFragment *MCObjectStreamer::getCurrentFragment() const {
53 assert(getCurrentSectionData() && "No current section!");
55 if (!getCurrentSectionData()->empty())
56 return &getCurrentSectionData()->getFragmentList().back();
61 MCDataFragment *MCObjectStreamer::getOrCreateDataFragment() const {
62 MCDataFragment *F = dyn_cast_or_null<MCDataFragment>(getCurrentFragment());
64 F = new MCDataFragment(getCurrentSectionData());
68 const MCExpr *MCObjectStreamer::AddValueSymbols(const MCExpr *Value) {
69 switch (Value->getKind()) {
71 cast<MCTargetExpr>(Value)->AddValueSymbols(Assembler);
74 case MCExpr::Constant:
77 case MCExpr::Binary: {
78 const MCBinaryExpr *BE = cast<MCBinaryExpr>(Value);
79 AddValueSymbols(BE->getLHS());
80 AddValueSymbols(BE->getRHS());
84 case MCExpr::SymbolRef:
85 Assembler->getOrCreateSymbolData(cast<MCSymbolRefExpr>(Value)->getSymbol());
89 AddValueSymbols(cast<MCUnaryExpr>(Value)->getSubExpr());
96 void MCObjectStreamer::EmitValueImpl(const MCExpr *Value, unsigned Size,
98 assert(AddrSpace == 0 && "Address space must be 0!");
99 MCDataFragment *DF = getOrCreateDataFragment();
101 // Avoid fixups when possible.
103 if (AddValueSymbols(Value)->EvaluateAsAbsolute(AbsValue, getAssembler())) {
104 EmitIntValue(AbsValue, Size, AddrSpace);
107 DF->getFixups().push_back(
108 MCFixup::Create(DF->getContents().size(), Value,
109 MCFixup::getKindForSize(Size, false)));
110 DF->getContents().resize(DF->getContents().size() + Size, 0);
113 void MCObjectStreamer::EmitCFIStartProcImpl(MCDwarfFrameInfo &Frame) {
114 RecordProcStart(Frame);
117 void MCObjectStreamer::EmitCFIEndProcImpl(MCDwarfFrameInfo &Frame) {
118 RecordProcEnd(Frame);
121 void MCObjectStreamer::EmitLabel(MCSymbol *Symbol) {
122 MCStreamer::EmitLabel(Symbol);
124 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
126 // FIXME: This is wasteful, we don't necessarily need to create a data
127 // fragment. Instead, we should mark the symbol as pointing into the data
128 // fragment if it exists, otherwise we should just queue the label and set its
129 // fragment pointer when we emit the next fragment.
130 MCDataFragment *F = getOrCreateDataFragment();
131 assert(!SD.getFragment() && "Unexpected fragment on symbol data!");
133 SD.setOffset(F->getContents().size());
136 void MCObjectStreamer::EmitULEB128Value(const MCExpr *Value) {
138 if (Value->EvaluateAsAbsolute(IntValue, getAssembler())) {
139 EmitULEB128IntValue(IntValue);
142 Value = ForceExpAbs(Value);
143 new MCLEBFragment(*Value, false, getCurrentSectionData());
146 void MCObjectStreamer::EmitSLEB128Value(const MCExpr *Value) {
148 if (Value->EvaluateAsAbsolute(IntValue, getAssembler())) {
149 EmitSLEB128IntValue(IntValue);
152 Value = ForceExpAbs(Value);
153 new MCLEBFragment(*Value, true, getCurrentSectionData());
156 void MCObjectStreamer::EmitWeakReference(MCSymbol *Alias,
157 const MCSymbol *Symbol) {
158 report_fatal_error("This file format doesn't support weak aliases.");
161 void MCObjectStreamer::ChangeSection(const MCSection *Section) {
162 assert(Section && "Cannot switch to a null section!");
164 CurSectionData = &getAssembler().getOrCreateSectionData(*Section);
167 void MCObjectStreamer::EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) {
168 getAssembler().getOrCreateSymbolData(*Symbol);
169 Symbol->setVariableValue(AddValueSymbols(Value));
172 void MCObjectStreamer::EmitInstruction(const MCInst &Inst) {
174 for (unsigned i = Inst.getNumOperands(); i--; )
175 if (Inst.getOperand(i).isExpr())
176 AddValueSymbols(Inst.getOperand(i).getExpr());
178 getCurrentSectionData()->setHasInstructions(true);
180 // Now that a machine instruction has been assembled into this section, make
181 // a line entry for any .loc directive that has been seen.
182 MCLineEntry::Make(this, getCurrentSection());
184 // If this instruction doesn't need relaxation, just emit it as data.
185 if (!getAssembler().getBackend().mayNeedRelaxation(Inst)) {
186 EmitInstToData(Inst);
190 // Otherwise, if we are relaxing everything, relax the instruction as much as
191 // possible and emit it as data.
192 if (getAssembler().getRelaxAll()) {
194 getAssembler().getBackend().relaxInstruction(Inst, Relaxed);
195 while (getAssembler().getBackend().mayNeedRelaxation(Relaxed))
196 getAssembler().getBackend().relaxInstruction(Relaxed, Relaxed);
197 EmitInstToData(Relaxed);
201 // Otherwise emit to a separate fragment.
202 EmitInstToFragment(Inst);
205 void MCObjectStreamer::EmitInstToFragment(const MCInst &Inst) {
206 MCInstFragment *IF = new MCInstFragment(Inst, getCurrentSectionData());
208 SmallString<128> Code;
209 raw_svector_ostream VecOS(Code);
210 getAssembler().getEmitter().EncodeInstruction(Inst, VecOS, IF->getFixups());
212 IF->getContents().append(Code.begin(), Code.end());
215 void MCObjectStreamer::EmitDwarfAdvanceLineAddr(int64_t LineDelta,
216 const MCSymbol *LastLabel,
217 const MCSymbol *Label,
218 unsigned PointerSize) {
220 EmitDwarfSetLineAddr(LineDelta, Label, PointerSize);
223 const MCExpr *AddrDelta = BuildSymbolDiff(getContext(), Label, LastLabel);
225 if (AddrDelta->EvaluateAsAbsolute(Res, getAssembler())) {
226 MCDwarfLineAddr::Emit(this, LineDelta, Res);
229 AddrDelta = ForceExpAbs(AddrDelta);
230 new MCDwarfLineAddrFragment(LineDelta, *AddrDelta, getCurrentSectionData());
233 void MCObjectStreamer::EmitDwarfAdvanceFrameAddr(const MCSymbol *LastLabel,
234 const MCSymbol *Label) {
235 const MCExpr *AddrDelta = BuildSymbolDiff(getContext(), Label, LastLabel);
237 if (AddrDelta->EvaluateAsAbsolute(Res, getAssembler())) {
238 MCDwarfFrameEmitter::EmitAdvanceLoc(*this, Res);
241 AddrDelta = ForceExpAbs(AddrDelta);
242 new MCDwarfCallFrameFragment(*AddrDelta, getCurrentSectionData());
245 void MCObjectStreamer::EmitBytes(StringRef Data, unsigned AddrSpace) {
246 assert(AddrSpace == 0 && "Address space must be 0!");
247 getOrCreateDataFragment()->getContents().append(Data.begin(), Data.end());
250 void MCObjectStreamer::EmitValueToAlignment(unsigned ByteAlignment,
253 unsigned MaxBytesToEmit) {
254 if (MaxBytesToEmit == 0)
255 MaxBytesToEmit = ByteAlignment;
256 new MCAlignFragment(ByteAlignment, Value, ValueSize, MaxBytesToEmit,
257 getCurrentSectionData());
259 // Update the maximum alignment on the current section if necessary.
260 if (ByteAlignment > getCurrentSectionData()->getAlignment())
261 getCurrentSectionData()->setAlignment(ByteAlignment);
264 void MCObjectStreamer::EmitCodeAlignment(unsigned ByteAlignment,
265 unsigned MaxBytesToEmit) {
266 EmitValueToAlignment(ByteAlignment, 0, 1, MaxBytesToEmit);
267 cast<MCAlignFragment>(getCurrentFragment())->setEmitNops(true);
270 bool MCObjectStreamer::EmitValueToOffset(const MCExpr *Offset,
271 unsigned char Value) {
273 if (Offset->EvaluateAsAbsolute(Res, getAssembler())) {
274 new MCOrgFragment(*Offset, Value, getCurrentSectionData());
278 MCSymbol *CurrentPos = getContext().CreateTempSymbol();
279 EmitLabel(CurrentPos);
280 MCSymbolRefExpr::VariantKind Variant = MCSymbolRefExpr::VK_None;
282 MCSymbolRefExpr::Create(CurrentPos, Variant, getContext());
283 const MCExpr *Delta =
284 MCBinaryExpr::Create(MCBinaryExpr::Sub, Offset, Ref, getContext());
286 if (!Delta->EvaluateAsAbsolute(Res, getAssembler()))
288 EmitFill(Res, Value, 0);
292 // Associate GPRel32 fixup with data and resize data area
293 void MCObjectStreamer::EmitGPRel32Value(const MCExpr *Value) {
294 MCDataFragment *DF = getOrCreateDataFragment();
296 DF->getFixups().push_back(MCFixup::Create(DF->getContents().size(),
298 DF->getContents().resize(DF->getContents().size() + 4, 0);
301 // Associate GPRel32 fixup with data and resize data area
302 void MCObjectStreamer::EmitGPRel64Value(const MCExpr *Value) {
303 MCDataFragment *DF = getOrCreateDataFragment();
305 DF->getFixups().push_back(MCFixup::Create(DF->getContents().size(),
307 DF->getContents().resize(DF->getContents().size() + 8, 0);
310 void MCObjectStreamer::EmitFill(uint64_t NumBytes, uint8_t FillValue,
311 unsigned AddrSpace) {
312 assert(AddrSpace == 0 && "Address space must be 0!");
313 // FIXME: A MCFillFragment would be more memory efficient but MCExpr has
314 // problems evaluating expressions across multiple fragments.
315 getOrCreateDataFragment()->getContents().append(NumBytes, FillValue);
318 void MCObjectStreamer::FinishImpl() {
319 // Dump out the dwarf file & directory tables and line tables.
320 const MCSymbol *LineSectionSymbol = NULL;
321 if (getContext().hasDwarfFiles())
322 LineSectionSymbol = MCDwarfFileTable::Emit(this);
324 // If we are generating dwarf for assembly source files dump out the sections.
325 if (getContext().getGenDwarfForAssembly())
326 MCGenDwarfInfo::Emit(this, LineSectionSymbol);
328 getAssembler().Finish();