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(StreamerKind Kind, MCContext &Context,
24 MCAsmBackend &TAB, raw_ostream &OS,
25 MCCodeEmitter *Emitter_)
26 : MCStreamer(Kind, Context),
27 Assembler(new MCAssembler(Context, TAB, *Emitter_,
28 *TAB.createObjectWriter(OS), OS)),
31 MCObjectStreamer::MCObjectStreamer(StreamerKind Kind, MCContext &Context,
32 MCAsmBackend &TAB, raw_ostream &OS,
33 MCCodeEmitter *Emitter_,
34 MCAssembler *_Assembler)
35 : MCStreamer(Kind, Context), Assembler(_Assembler), CurSectionData(0) {}
37 MCObjectStreamer::~MCObjectStreamer() {
38 delete &Assembler->getBackend();
39 delete &Assembler->getEmitter();
40 delete &Assembler->getWriter();
44 void MCObjectStreamer::reset() {
51 MCFragment *MCObjectStreamer::getCurrentFragment() const {
52 assert(getCurrentSectionData() && "No current section!");
54 if (!getCurrentSectionData()->empty())
55 return &getCurrentSectionData()->getFragmentList().back();
60 MCDataFragment *MCObjectStreamer::getOrCreateDataFragment() const {
61 MCDataFragment *F = dyn_cast_or_null<MCDataFragment>(getCurrentFragment());
63 F = new MCDataFragment(getCurrentSectionData());
67 const MCExpr *MCObjectStreamer::AddValueSymbols(const MCExpr *Value) {
68 switch (Value->getKind()) {
70 cast<MCTargetExpr>(Value)->AddValueSymbols(Assembler);
73 case MCExpr::Constant:
76 case MCExpr::Binary: {
77 const MCBinaryExpr *BE = cast<MCBinaryExpr>(Value);
78 AddValueSymbols(BE->getLHS());
79 AddValueSymbols(BE->getRHS());
83 case MCExpr::SymbolRef:
84 Assembler->getOrCreateSymbolData(cast<MCSymbolRefExpr>(Value)->getSymbol());
88 AddValueSymbols(cast<MCUnaryExpr>(Value)->getSubExpr());
95 void MCObjectStreamer::EmitValueImpl(const MCExpr *Value, unsigned Size,
97 assert(AddrSpace == 0 && "Address space must be 0!");
98 MCDataFragment *DF = getOrCreateDataFragment();
100 // Avoid fixups when possible.
102 if (AddValueSymbols(Value)->EvaluateAsAbsolute(AbsValue, getAssembler())) {
103 EmitIntValue(AbsValue, Size, AddrSpace);
106 DF->getFixups().push_back(
107 MCFixup::Create(DF->getContents().size(), Value,
108 MCFixup::getKindForSize(Size, false)));
109 DF->getContents().resize(DF->getContents().size() + Size, 0);
112 void MCObjectStreamer::EmitCFIStartProcImpl(MCDwarfFrameInfo &Frame) {
113 RecordProcStart(Frame);
116 void MCObjectStreamer::EmitCFIEndProcImpl(MCDwarfFrameInfo &Frame) {
117 RecordProcEnd(Frame);
120 void MCObjectStreamer::EmitLabel(MCSymbol *Symbol) {
121 MCStreamer::EmitLabel(Symbol);
123 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
125 // FIXME: This is wasteful, we don't necessarily need to create a data
126 // fragment. Instead, we should mark the symbol as pointing into the data
127 // fragment if it exists, otherwise we should just queue the label and set its
128 // fragment pointer when we emit the next fragment.
129 MCDataFragment *F = getOrCreateDataFragment();
130 assert(!SD.getFragment() && "Unexpected fragment on symbol data!");
132 SD.setOffset(F->getContents().size());
135 void MCObjectStreamer::EmitDebugLabel(MCSymbol *Symbol) {
139 void MCObjectStreamer::EmitULEB128Value(const MCExpr *Value) {
141 if (Value->EvaluateAsAbsolute(IntValue, getAssembler())) {
142 EmitULEB128IntValue(IntValue);
145 Value = ForceExpAbs(Value);
146 new MCLEBFragment(*Value, false, getCurrentSectionData());
149 void MCObjectStreamer::EmitSLEB128Value(const MCExpr *Value) {
151 if (Value->EvaluateAsAbsolute(IntValue, getAssembler())) {
152 EmitSLEB128IntValue(IntValue);
155 Value = ForceExpAbs(Value);
156 new MCLEBFragment(*Value, true, getCurrentSectionData());
159 void MCObjectStreamer::EmitWeakReference(MCSymbol *Alias,
160 const MCSymbol *Symbol) {
161 report_fatal_error("This file format doesn't support weak aliases.");
164 void MCObjectStreamer::ChangeSection(const MCSection *Section) {
165 assert(Section && "Cannot switch to a null section!");
167 CurSectionData = &getAssembler().getOrCreateSectionData(*Section);
170 void MCObjectStreamer::EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) {
171 getAssembler().getOrCreateSymbolData(*Symbol);
172 Symbol->setVariableValue(AddValueSymbols(Value));
175 void MCObjectStreamer::EmitInstruction(const MCInst &Inst) {
177 for (unsigned i = Inst.getNumOperands(); i--; )
178 if (Inst.getOperand(i).isExpr())
179 AddValueSymbols(Inst.getOperand(i).getExpr());
181 MCSectionData *SD = getCurrentSectionData();
182 SD->setHasInstructions(true);
184 // Now that a machine instruction has been assembled into this section, make
185 // a line entry for any .loc directive that has been seen.
186 MCLineEntry::Make(this, getCurrentSection());
188 // If this instruction doesn't need relaxation, just emit it as data.
189 MCAssembler &Assembler = getAssembler();
190 if (!Assembler.getBackend().mayNeedRelaxation(Inst)) {
191 EmitInstToData(Inst);
195 // Otherwise, relax and emit it as data if either:
196 // - The RelaxAll flag was passed
197 // - Bundling is enabled and this instruction is inside a bundle-locked
198 // group. We want to emit all such instructions into the same data
200 if (Assembler.getRelaxAll() ||
201 (Assembler.isBundlingEnabled() && SD->isBundleLocked())) {
203 getAssembler().getBackend().relaxInstruction(Inst, Relaxed);
204 while (getAssembler().getBackend().mayNeedRelaxation(Relaxed))
205 getAssembler().getBackend().relaxInstruction(Relaxed, Relaxed);
206 EmitInstToData(Relaxed);
210 // Otherwise emit to a separate fragment.
211 EmitInstToFragment(Inst);
214 void MCObjectStreamer::EmitInstToFragment(const MCInst &Inst) {
215 // Always create a new, separate fragment here, because its size can change
216 // during relaxation.
217 MCRelaxableFragment *IF =
218 new MCRelaxableFragment(Inst, getCurrentSectionData());
220 SmallString<128> Code;
221 raw_svector_ostream VecOS(Code);
222 getAssembler().getEmitter().EncodeInstruction(Inst, VecOS, IF->getFixups());
224 IF->getContents().append(Code.begin(), Code.end());
227 const char *BundlingNotImplementedMsg =
228 "Aligned bundling is not implemented for this object format";
230 void MCObjectStreamer::EmitBundleAlignMode(unsigned AlignPow2) {
231 llvm_unreachable(BundlingNotImplementedMsg);
234 void MCObjectStreamer::EmitBundleLock(bool AlignToEnd) {
235 llvm_unreachable(BundlingNotImplementedMsg);
238 void MCObjectStreamer::EmitBundleUnlock() {
239 llvm_unreachable(BundlingNotImplementedMsg);
242 void MCObjectStreamer::EmitDwarfAdvanceLineAddr(int64_t LineDelta,
243 const MCSymbol *LastLabel,
244 const MCSymbol *Label,
245 unsigned PointerSize) {
247 EmitDwarfSetLineAddr(LineDelta, Label, PointerSize);
250 const MCExpr *AddrDelta = BuildSymbolDiff(getContext(), Label, LastLabel);
252 if (AddrDelta->EvaluateAsAbsolute(Res, getAssembler())) {
253 MCDwarfLineAddr::Emit(this, LineDelta, Res);
256 AddrDelta = ForceExpAbs(AddrDelta);
257 new MCDwarfLineAddrFragment(LineDelta, *AddrDelta, getCurrentSectionData());
260 void MCObjectStreamer::EmitDwarfAdvanceFrameAddr(const MCSymbol *LastLabel,
261 const MCSymbol *Label) {
262 const MCExpr *AddrDelta = BuildSymbolDiff(getContext(), Label, LastLabel);
264 if (AddrDelta->EvaluateAsAbsolute(Res, getAssembler())) {
265 MCDwarfFrameEmitter::EmitAdvanceLoc(*this, Res);
268 AddrDelta = ForceExpAbs(AddrDelta);
269 new MCDwarfCallFrameFragment(*AddrDelta, getCurrentSectionData());
272 void MCObjectStreamer::EmitBytes(StringRef Data, unsigned AddrSpace) {
273 assert(AddrSpace == 0 && "Address space must be 0!");
274 getOrCreateDataFragment()->getContents().append(Data.begin(), Data.end());
277 void MCObjectStreamer::EmitValueToAlignment(unsigned ByteAlignment,
280 unsigned MaxBytesToEmit) {
281 if (MaxBytesToEmit == 0)
282 MaxBytesToEmit = ByteAlignment;
283 new MCAlignFragment(ByteAlignment, Value, ValueSize, MaxBytesToEmit,
284 getCurrentSectionData());
286 // Update the maximum alignment on the current section if necessary.
287 if (ByteAlignment > getCurrentSectionData()->getAlignment())
288 getCurrentSectionData()->setAlignment(ByteAlignment);
291 void MCObjectStreamer::EmitCodeAlignment(unsigned ByteAlignment,
292 unsigned MaxBytesToEmit) {
293 EmitValueToAlignment(ByteAlignment, 0, 1, MaxBytesToEmit);
294 cast<MCAlignFragment>(getCurrentFragment())->setEmitNops(true);
297 bool MCObjectStreamer::EmitValueToOffset(const MCExpr *Offset,
298 unsigned char Value) {
300 if (Offset->EvaluateAsAbsolute(Res, getAssembler())) {
301 new MCOrgFragment(*Offset, Value, getCurrentSectionData());
305 MCSymbol *CurrentPos = getContext().CreateTempSymbol();
306 EmitLabel(CurrentPos);
307 MCSymbolRefExpr::VariantKind Variant = MCSymbolRefExpr::VK_None;
309 MCSymbolRefExpr::Create(CurrentPos, Variant, getContext());
310 const MCExpr *Delta =
311 MCBinaryExpr::Create(MCBinaryExpr::Sub, Offset, Ref, getContext());
313 if (!Delta->EvaluateAsAbsolute(Res, getAssembler()))
315 EmitFill(Res, Value);
319 // Associate GPRel32 fixup with data and resize data area
320 void MCObjectStreamer::EmitGPRel32Value(const MCExpr *Value) {
321 MCDataFragment *DF = getOrCreateDataFragment();
323 DF->getFixups().push_back(MCFixup::Create(DF->getContents().size(),
325 DF->getContents().resize(DF->getContents().size() + 4, 0);
328 // Associate GPRel32 fixup with data and resize data area
329 void MCObjectStreamer::EmitGPRel64Value(const MCExpr *Value) {
330 MCDataFragment *DF = getOrCreateDataFragment();
332 DF->getFixups().push_back(MCFixup::Create(DF->getContents().size(),
334 DF->getContents().resize(DF->getContents().size() + 8, 0);
337 void MCObjectStreamer::EmitFill(uint64_t NumBytes, uint8_t FillValue,
338 unsigned AddrSpace) {
339 assert(AddrSpace == 0 && "Address space must be 0!");
340 // FIXME: A MCFillFragment would be more memory efficient but MCExpr has
341 // problems evaluating expressions across multiple fragments.
342 getOrCreateDataFragment()->getContents().append(NumBytes, FillValue);
345 void MCObjectStreamer::FinishImpl() {
346 // Dump out the dwarf file & directory tables and line tables.
347 const MCSymbol *LineSectionSymbol = NULL;
348 if (getContext().hasDwarfFiles())
349 LineSectionSymbol = MCDwarfFileTable::Emit(this);
351 // If we are generating dwarf for assembly source files dump out the sections.
352 if (getContext().getGenDwarfForAssembly())
353 MCGenDwarfInfo::Emit(this, LineSectionSymbol);
355 getAssembler().Finish();