1 //===- lib/MC/MCDwarf.cpp - MCDwarf implementation ------------------------===//
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/ADT/FoldingSet.h"
11 #include "llvm/MC/MCAsmInfo.h"
12 #include "llvm/MC/MCDwarf.h"
13 #include "llvm/MC/MCAssembler.h"
14 #include "llvm/MC/MCStreamer.h"
15 #include "llvm/MC/MCSymbol.h"
16 #include "llvm/MC/MCExpr.h"
17 #include "llvm/MC/MCContext.h"
18 #include "llvm/MC/MCObjectWriter.h"
19 #include "llvm/ADT/SmallString.h"
20 #include "llvm/ADT/Twine.h"
21 #include "llvm/Support/Debug.h"
22 #include "llvm/Support/ErrorHandling.h"
23 #include "llvm/Support/raw_ostream.h"
24 #include "llvm/Target/TargetAsmBackend.h"
25 #include "llvm/Target/TargetAsmInfo.h"
28 // Given a special op, return the address skip amount (in units of
29 // DWARF2_LINE_MIN_INSN_LENGTH.
30 #define SPECIAL_ADDR(op) (((op) - DWARF2_LINE_OPCODE_BASE)/DWARF2_LINE_RANGE)
32 // The maximum address skip amount that can be encoded with a special op.
33 #define MAX_SPECIAL_ADDR_DELTA SPECIAL_ADDR(255)
35 // First special line opcode - leave room for the standard opcodes.
36 // Note: If you want to change this, you'll have to update the
37 // "standard_opcode_lengths" table that is emitted in DwarfFileTable::Emit().
38 #define DWARF2_LINE_OPCODE_BASE 13
40 // Minimum line offset in a special line info. opcode. This value
41 // was chosen to give a reasonable range of values.
42 #define DWARF2_LINE_BASE -5
44 // Range of line offsets in a special line info. opcode.
45 # define DWARF2_LINE_RANGE 14
47 // Define the architecture-dependent minimum instruction length (in bytes).
48 // This value should be rather too small than too big.
49 # define DWARF2_LINE_MIN_INSN_LENGTH 1
51 // Note: when DWARF2_LINE_MIN_INSN_LENGTH == 1 which is the current setting,
52 // this routine is a nop and will be optimized away.
53 static inline uint64_t ScaleAddrDelta(uint64_t AddrDelta)
55 if (DWARF2_LINE_MIN_INSN_LENGTH == 1)
57 if (AddrDelta % DWARF2_LINE_MIN_INSN_LENGTH != 0) {
58 // TODO: report this error, but really only once.
61 return AddrDelta / DWARF2_LINE_MIN_INSN_LENGTH;
65 // This is called when an instruction is assembled into the specified section
66 // and if there is information from the last .loc directive that has yet to have
67 // a line entry made for it is made.
69 void MCLineEntry::Make(MCStreamer *MCOS, const MCSection *Section) {
70 if (!MCOS->getContext().getDwarfLocSeen())
73 // Create a symbol at in the current section for use in the line entry.
74 MCSymbol *LineSym = MCOS->getContext().CreateTempSymbol();
75 // Set the value of the symbol to use for the MCLineEntry.
76 MCOS->EmitLabel(LineSym);
78 // Get the current .loc info saved in the context.
79 const MCDwarfLoc &DwarfLoc = MCOS->getContext().getCurrentDwarfLoc();
81 // Create a (local) line entry with the symbol and the current .loc info.
82 MCLineEntry LineEntry(LineSym, DwarfLoc);
84 // clear DwarfLocSeen saying the current .loc info is now used.
85 MCOS->getContext().ClearDwarfLocSeen();
87 // Get the MCLineSection for this section, if one does not exist for this
89 const DenseMap<const MCSection *, MCLineSection *> &MCLineSections =
90 MCOS->getContext().getMCLineSections();
91 MCLineSection *LineSection = MCLineSections.lookup(Section);
93 // Create a new MCLineSection. This will be deleted after the dwarf line
94 // table is created using it by iterating through the MCLineSections
96 LineSection = new MCLineSection;
97 // Save a pointer to the new LineSection into the MCLineSections DenseMap.
98 MCOS->getContext().addMCLineSection(Section, LineSection);
101 // Add the line entry to this section's entries.
102 LineSection->addLineEntry(LineEntry);
106 // This helper routine returns an expression of End - Start + IntVal .
108 static inline const MCExpr *MakeStartMinusEndExpr(const MCStreamer &MCOS,
109 const MCSymbol &Start,
112 MCSymbolRefExpr::VariantKind Variant = MCSymbolRefExpr::VK_None;
114 MCSymbolRefExpr::Create(&End, Variant, MCOS.getContext());
116 MCSymbolRefExpr::Create(&Start, Variant, MCOS.getContext());
118 MCBinaryExpr::Create(MCBinaryExpr::Sub, Res, RHS, MCOS.getContext());
120 MCConstantExpr::Create(IntVal, MCOS.getContext());
122 MCBinaryExpr::Create(MCBinaryExpr::Sub, Res1, Res2, MCOS.getContext());
127 // This emits the Dwarf line table for the specified section from the entries
128 // in the LineSection.
130 static inline void EmitDwarfLineTable(MCStreamer *MCOS,
131 const MCSection *Section,
132 const MCLineSection *LineSection) {
133 unsigned FileNum = 1;
134 unsigned LastLine = 1;
136 unsigned Flags = DWARF2_LINE_DEFAULT_IS_STMT ? DWARF2_FLAG_IS_STMT : 0;
138 MCSymbol *LastLabel = NULL;
140 // Loop through each MCLineEntry and encode the dwarf line number table.
141 for (MCLineSection::const_iterator
142 it = LineSection->getMCLineEntries()->begin(),
143 ie = LineSection->getMCLineEntries()->end(); it != ie; ++it) {
145 if (FileNum != it->getFileNum()) {
146 FileNum = it->getFileNum();
147 MCOS->EmitIntValue(dwarf::DW_LNS_set_file, 1);
148 MCOS->EmitULEB128IntValue(FileNum);
150 if (Column != it->getColumn()) {
151 Column = it->getColumn();
152 MCOS->EmitIntValue(dwarf::DW_LNS_set_column, 1);
153 MCOS->EmitULEB128IntValue(Column);
155 if (Isa != it->getIsa()) {
157 MCOS->EmitIntValue(dwarf::DW_LNS_set_isa, 1);
158 MCOS->EmitULEB128IntValue(Isa);
160 if ((it->getFlags() ^ Flags) & DWARF2_FLAG_IS_STMT) {
161 Flags = it->getFlags();
162 MCOS->EmitIntValue(dwarf::DW_LNS_negate_stmt, 1);
164 if (it->getFlags() & DWARF2_FLAG_BASIC_BLOCK)
165 MCOS->EmitIntValue(dwarf::DW_LNS_set_basic_block, 1);
166 if (it->getFlags() & DWARF2_FLAG_PROLOGUE_END)
167 MCOS->EmitIntValue(dwarf::DW_LNS_set_prologue_end, 1);
168 if (it->getFlags() & DWARF2_FLAG_EPILOGUE_BEGIN)
169 MCOS->EmitIntValue(dwarf::DW_LNS_set_epilogue_begin, 1);
171 int64_t LineDelta = static_cast<int64_t>(it->getLine()) - LastLine;
172 MCSymbol *Label = it->getLabel();
174 // At this point we want to emit/create the sequence to encode the delta in
175 // line numbers and the increment of the address from the previous Label
176 // and the current Label.
177 MCOS->EmitDwarfAdvanceLineAddr(LineDelta, LastLabel, Label);
179 LastLine = it->getLine();
183 // Emit a DW_LNE_end_sequence for the end of the section.
184 // Using the pointer Section create a temporary label at the end of the
185 // section and use that and the LastLabel to compute the address delta
186 // and use INT64_MAX as the line delta which is the signal that this is
187 // actually a DW_LNE_end_sequence.
189 // Switch to the section to be able to create a symbol at its end.
190 MCOS->SwitchSection(Section);
192 MCContext &context = MCOS->getContext();
193 // Create a symbol at the end of the section.
194 MCSymbol *SectionEnd = context.CreateTempSymbol();
195 // Set the value of the symbol, as we are at the end of the section.
196 MCOS->EmitLabel(SectionEnd);
198 // Switch back the the dwarf line section.
199 MCOS->SwitchSection(context.getTargetAsmInfo().getDwarfLineSection());
201 MCOS->EmitDwarfAdvanceLineAddr(INT64_MAX, LastLabel, SectionEnd);
205 // This emits the Dwarf file and the line tables.
207 void MCDwarfFileTable::Emit(MCStreamer *MCOS) {
208 MCContext &context = MCOS->getContext();
209 // Switch to the section where the table will be emitted into.
210 MCOS->SwitchSection(context.getTargetAsmInfo().getDwarfLineSection());
212 // Create a symbol at the beginning of this section.
213 MCSymbol *LineStartSym = context.CreateTempSymbol();
214 // Set the value of the symbol, as we are at the start of the section.
215 MCOS->EmitLabel(LineStartSym);
217 // Create a symbol for the end of the section (to be set when we get there).
218 MCSymbol *LineEndSym = context.CreateTempSymbol();
220 // The first 4 bytes is the total length of the information for this
221 // compilation unit (not including these 4 bytes for the length).
222 MCOS->EmitAbsValue(MakeStartMinusEndExpr(*MCOS, *LineStartSym, *LineEndSym,4),
225 // Next 2 bytes is the Version, which is Dwarf 2.
226 MCOS->EmitIntValue(2, 2);
228 // Create a symbol for the end of the prologue (to be set when we get there).
229 MCSymbol *ProEndSym = context.CreateTempSymbol(); // Lprologue_end
231 // Length of the prologue, is the next 4 bytes. Which is the start of the
232 // section to the end of the prologue. Not including the 4 bytes for the
233 // total length, the 2 bytes for the version, and these 4 bytes for the
234 // length of the prologue.
235 MCOS->EmitAbsValue(MakeStartMinusEndExpr(*MCOS, *LineStartSym, *ProEndSym,
239 // Parameters of the state machine, are next.
240 MCOS->EmitIntValue(DWARF2_LINE_MIN_INSN_LENGTH, 1);
241 MCOS->EmitIntValue(DWARF2_LINE_DEFAULT_IS_STMT, 1);
242 MCOS->EmitIntValue(DWARF2_LINE_BASE, 1);
243 MCOS->EmitIntValue(DWARF2_LINE_RANGE, 1);
244 MCOS->EmitIntValue(DWARF2_LINE_OPCODE_BASE, 1);
246 // Standard opcode lengths
247 MCOS->EmitIntValue(0, 1); // length of DW_LNS_copy
248 MCOS->EmitIntValue(1, 1); // length of DW_LNS_advance_pc
249 MCOS->EmitIntValue(1, 1); // length of DW_LNS_advance_line
250 MCOS->EmitIntValue(1, 1); // length of DW_LNS_set_file
251 MCOS->EmitIntValue(1, 1); // length of DW_LNS_set_column
252 MCOS->EmitIntValue(0, 1); // length of DW_LNS_negate_stmt
253 MCOS->EmitIntValue(0, 1); // length of DW_LNS_set_basic_block
254 MCOS->EmitIntValue(0, 1); // length of DW_LNS_const_add_pc
255 MCOS->EmitIntValue(1, 1); // length of DW_LNS_fixed_advance_pc
256 MCOS->EmitIntValue(0, 1); // length of DW_LNS_set_prologue_end
257 MCOS->EmitIntValue(0, 1); // length of DW_LNS_set_epilogue_begin
258 MCOS->EmitIntValue(1, 1); // DW_LNS_set_isa
260 // Put out the directory and file tables.
262 // First the directory table.
263 const std::vector<StringRef> &MCDwarfDirs =
264 context.getMCDwarfDirs();
265 for (unsigned i = 0; i < MCDwarfDirs.size(); i++) {
266 MCOS->EmitBytes(MCDwarfDirs[i], 0); // the DirectoryName
267 MCOS->EmitBytes(StringRef("\0", 1), 0); // the null term. of the string
269 MCOS->EmitIntValue(0, 1); // Terminate the directory list
271 // Second the file table.
272 const std::vector<MCDwarfFile *> &MCDwarfFiles =
273 MCOS->getContext().getMCDwarfFiles();
274 for (unsigned i = 1; i < MCDwarfFiles.size(); i++) {
275 MCOS->EmitBytes(MCDwarfFiles[i]->getName(), 0); // FileName
276 MCOS->EmitBytes(StringRef("\0", 1), 0); // the null term. of the string
278 MCOS->EmitULEB128IntValue(MCDwarfFiles[i]->getDirIndex());
279 MCOS->EmitIntValue(0, 1); // last modification timestamp (always 0)
280 MCOS->EmitIntValue(0, 1); // filesize (always 0)
282 MCOS->EmitIntValue(0, 1); // Terminate the file list
284 // This is the end of the prologue, so set the value of the symbol at the
285 // end of the prologue (that was used in a previous expression).
286 MCOS->EmitLabel(ProEndSym);
288 // Put out the line tables.
289 const DenseMap<const MCSection *, MCLineSection *> &MCLineSections =
290 MCOS->getContext().getMCLineSections();
291 const std::vector<const MCSection *> &MCLineSectionOrder =
292 MCOS->getContext().getMCLineSectionOrder();
293 for (std::vector<const MCSection*>::const_iterator it =
294 MCLineSectionOrder.begin(), ie = MCLineSectionOrder.end(); it != ie;
296 const MCSection *Sec = *it;
297 const MCLineSection *Line = MCLineSections.lookup(Sec);
298 EmitDwarfLineTable(MCOS, Sec, Line);
300 // Now delete the MCLineSections that were created in MCLineEntry::Make()
301 // and used to emit the line table.
305 if (MCOS->getContext().getAsmInfo().getLinkerRequiresNonEmptyDwarfLines()
306 && MCLineSectionOrder.begin() == MCLineSectionOrder.end()) {
307 // The darwin9 linker has a bug (see PR8715). For for 32-bit architectures
309 // total_length >= prologue_length + 10
310 // We are 4 bytes short, since we have total_length = 51 and
311 // prologue_length = 45
313 // The regular end_sequence should be sufficient.
314 MCDwarfLineAddr::Emit(MCOS, INT64_MAX, 0);
317 // This is the end of the section, so set the value of the symbol at the end
318 // of this section (that was used in a previous expression).
319 MCOS->EmitLabel(LineEndSym);
322 /// Utility function to write the encoding to an object writer.
323 void MCDwarfLineAddr::Write(MCObjectWriter *OW, int64_t LineDelta,
324 uint64_t AddrDelta) {
325 SmallString<256> Tmp;
326 raw_svector_ostream OS(Tmp);
327 MCDwarfLineAddr::Encode(LineDelta, AddrDelta, OS);
328 OW->WriteBytes(OS.str());
331 /// Utility function to emit the encoding to a streamer.
332 void MCDwarfLineAddr::Emit(MCStreamer *MCOS, int64_t LineDelta,
333 uint64_t AddrDelta) {
334 SmallString<256> Tmp;
335 raw_svector_ostream OS(Tmp);
336 MCDwarfLineAddr::Encode(LineDelta, AddrDelta, OS);
337 MCOS->EmitBytes(OS.str(), /*AddrSpace=*/0);
340 /// Utility function to encode a Dwarf pair of LineDelta and AddrDeltas.
341 void MCDwarfLineAddr::Encode(int64_t LineDelta, uint64_t AddrDelta,
343 uint64_t Temp, Opcode;
344 bool NeedCopy = false;
346 // Scale the address delta by the minimum instruction length.
347 AddrDelta = ScaleAddrDelta(AddrDelta);
349 // A LineDelta of INT64_MAX is a signal that this is actually a
350 // DW_LNE_end_sequence. We cannot use special opcodes here, since we want the
351 // end_sequence to emit the matrix entry.
352 if (LineDelta == INT64_MAX) {
353 if (AddrDelta == MAX_SPECIAL_ADDR_DELTA)
354 OS << char(dwarf::DW_LNS_const_add_pc);
356 OS << char(dwarf::DW_LNS_advance_pc);
358 raw_svector_ostream OSE(Tmp);
359 MCObjectWriter::EncodeULEB128(AddrDelta, OSE);
362 OS << char(dwarf::DW_LNS_extended_op);
364 OS << char(dwarf::DW_LNE_end_sequence);
368 // Bias the line delta by the base.
369 Temp = LineDelta - DWARF2_LINE_BASE;
371 // If the line increment is out of range of a special opcode, we must encode
372 // it with DW_LNS_advance_line.
373 if (Temp >= DWARF2_LINE_RANGE) {
374 OS << char(dwarf::DW_LNS_advance_line);
376 raw_svector_ostream OSE(Tmp);
377 MCObjectWriter::EncodeSLEB128(LineDelta, OSE);
381 Temp = 0 - DWARF2_LINE_BASE;
385 // Use DW_LNS_copy instead of a "line +0, addr +0" special opcode.
386 if (LineDelta == 0 && AddrDelta == 0) {
387 OS << char(dwarf::DW_LNS_copy);
391 // Bias the opcode by the special opcode base.
392 Temp += DWARF2_LINE_OPCODE_BASE;
394 // Avoid overflow when addr_delta is large.
395 if (AddrDelta < 256 + MAX_SPECIAL_ADDR_DELTA) {
396 // Try using a special opcode.
397 Opcode = Temp + AddrDelta * DWARF2_LINE_RANGE;
403 // Try using DW_LNS_const_add_pc followed by special op.
404 Opcode = Temp + (AddrDelta - MAX_SPECIAL_ADDR_DELTA) * DWARF2_LINE_RANGE;
406 OS << char(dwarf::DW_LNS_const_add_pc);
412 // Otherwise use DW_LNS_advance_pc.
413 OS << char(dwarf::DW_LNS_advance_pc);
415 raw_svector_ostream OSE(Tmp);
416 MCObjectWriter::EncodeULEB128(AddrDelta, OSE);
420 OS << char(dwarf::DW_LNS_copy);
425 void MCDwarfFile::print(raw_ostream &OS) const {
426 OS << '"' << getName() << '"';
429 void MCDwarfFile::dump() const {
433 static int getDataAlignmentFactor(MCStreamer &streamer) {
434 MCContext &context = streamer.getContext();
435 const TargetAsmInfo &asmInfo = context.getTargetAsmInfo();
436 int size = asmInfo.getPointerSize();
437 if (asmInfo.getStackGrowthDirection() == TargetFrameLowering::StackGrowsUp)
443 static unsigned getSizeForEncoding(MCStreamer &streamer,
444 unsigned symbolEncoding) {
445 MCContext &context = streamer.getContext();
446 const TargetAsmInfo &asmInfo = context.getTargetAsmInfo();
447 unsigned format = symbolEncoding & 0x0f;
450 assert(0 && "Unknown Encoding");
451 case dwarf::DW_EH_PE_absptr:
452 case dwarf::DW_EH_PE_signed:
453 return asmInfo.getPointerSize();
454 case dwarf::DW_EH_PE_udata2:
455 case dwarf::DW_EH_PE_sdata2:
457 case dwarf::DW_EH_PE_udata4:
458 case dwarf::DW_EH_PE_sdata4:
460 case dwarf::DW_EH_PE_udata8:
461 case dwarf::DW_EH_PE_sdata8:
466 static void EmitSymbol(MCStreamer &streamer, const MCSymbol &symbol,
467 unsigned symbolEncoding) {
468 unsigned size = getSizeForEncoding(streamer, symbolEncoding);
469 unsigned application = symbolEncoding & 0x70;
470 switch (application) {
472 assert(0 && "Unknown Encoding");
475 streamer.EmitSymbolValue(&symbol, size);
477 case dwarf::DW_EH_PE_pcrel:
478 streamer.EmitPCRelSymbolValue(&symbol, size);
483 static void EmitPersonality(MCStreamer &streamer, const MCSymbol &symbol,
484 unsigned symbolEncoding) {
485 MCContext &context = streamer.getContext();
486 const MCAsmInfo &asmInfo = context.getAsmInfo();
487 const MCExpr *v = asmInfo.getExprForPersonalitySymbol(&symbol, streamer);
488 unsigned size = getSizeForEncoding(streamer, symbolEncoding);
489 unsigned application = symbolEncoding & 0x70;
490 if (isa<MCSymbolRefExpr>(v) && application == dwarf::DW_EH_PE_pcrel)
491 streamer.EmitPCRelValue(v, size);
493 streamer.EmitValue(v, size);
496 static const MachineLocation TranslateMachineLocation(
497 const TargetAsmInfo &AsmInfo,
498 const MachineLocation &Loc) {
499 unsigned Reg = Loc.getReg() == MachineLocation::VirtualFP ?
500 MachineLocation::VirtualFP :
501 unsigned(AsmInfo.getDwarfRegNum(Loc.getReg(), true));
502 const MachineLocation &NewLoc = Loc.isReg() ?
503 MachineLocation(Reg) : MachineLocation(Reg, Loc.getOffset());
508 class FrameEmitterImpl {
513 FrameEmitterImpl() : CFAOffset(0), CIENum(0) {
516 const MCSymbol &EmitCIE(MCStreamer &streamer,
517 const MCSymbol *personality,
518 unsigned personalityEncoding,
519 const MCSymbol *lsda,
520 unsigned lsdaEncoding);
521 MCSymbol *EmitFDE(MCStreamer &streamer,
522 const MCSymbol &cieStart,
523 const MCDwarfFrameInfo &frame);
524 void EmitCFIInstructions(MCStreamer &streamer,
525 const std::vector<MCCFIInstruction> &Instrs,
526 MCSymbol *BaseLabel);
527 void EmitCFIInstruction(MCStreamer &Streamer,
528 const MCCFIInstruction &Instr);
532 void FrameEmitterImpl::EmitCFIInstruction(MCStreamer &Streamer,
533 const MCCFIInstruction &Instr) {
534 int dataAlignmentFactor = getDataAlignmentFactor(Streamer);
536 switch (Instr.getOperation()) {
537 case MCCFIInstruction::Move:
538 case MCCFIInstruction::RelMove: {
539 const MachineLocation &Dst = Instr.getDestination();
540 const MachineLocation &Src = Instr.getSource();
541 const bool IsRelative = Instr.getOperation() == MCCFIInstruction::RelMove;
544 if (Dst.isReg() && Dst.getReg() == MachineLocation::VirtualFP) {
545 assert(!Src.isReg() && "Machine move not supported yet.");
547 if (Src.getReg() == MachineLocation::VirtualFP) {
548 Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa_offset, 1);
550 Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa, 1);
551 Streamer.EmitULEB128IntValue(Src.getReg());
555 CFAOffset += Src.getOffset();
557 CFAOffset = -Src.getOffset();
559 Streamer.EmitULEB128IntValue(CFAOffset);
563 if (Src.isReg() && Src.getReg() == MachineLocation::VirtualFP) {
564 assert(Dst.isReg() && "Machine move not supported yet.");
565 Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa_register, 1);
566 Streamer.EmitULEB128IntValue(Dst.getReg());
570 unsigned Reg = Src.getReg();
572 int Offset = Dst.getOffset();
575 Offset = Offset / dataAlignmentFactor;
578 Streamer.EmitIntValue(dwarf::DW_CFA_offset_extended_sf, 1);
579 Streamer.EmitULEB128IntValue(Reg);
580 Streamer.EmitSLEB128IntValue(Offset);
581 } else if (Reg < 64) {
582 Streamer.EmitIntValue(dwarf::DW_CFA_offset + Reg, 1);
583 Streamer.EmitULEB128IntValue(Offset);
585 Streamer.EmitIntValue(dwarf::DW_CFA_offset_extended, 1);
586 Streamer.EmitULEB128IntValue(Reg);
587 Streamer.EmitULEB128IntValue(Offset);
591 case MCCFIInstruction::Remember:
592 Streamer.EmitIntValue(dwarf::DW_CFA_remember_state, 1);
594 case MCCFIInstruction::Restore:
595 Streamer.EmitIntValue(dwarf::DW_CFA_restore_state, 1);
597 case MCCFIInstruction::SameValue: {
598 unsigned Reg = Instr.getDestination().getReg();
599 Streamer.EmitIntValue(dwarf::DW_CFA_same_value, 1);
600 Streamer.EmitULEB128IntValue(Reg);
604 llvm_unreachable("Unhandled case in switch");
607 /// EmitFrameMoves - Emit frame instructions to describe the layout of the
609 void FrameEmitterImpl::EmitCFIInstructions(MCStreamer &streamer,
610 const std::vector<MCCFIInstruction> &Instrs,
611 MCSymbol *BaseLabel) {
612 for (unsigned i = 0, N = Instrs.size(); i < N; ++i) {
613 const MCCFIInstruction &Instr = Instrs[i];
614 MCSymbol *Label = Instr.getLabel();
615 // Throw out move if the label is invalid.
616 if (Label && !Label->isDefined()) continue; // Not emitted, in dead code.
618 // Advance row if new location.
619 if (BaseLabel && Label) {
620 MCSymbol *ThisSym = Label;
621 if (ThisSym != BaseLabel) {
622 streamer.EmitDwarfAdvanceFrameAddr(BaseLabel, ThisSym);
627 EmitCFIInstruction(streamer, Instr);
631 const MCSymbol &FrameEmitterImpl::EmitCIE(MCStreamer &streamer,
632 const MCSymbol *personality,
633 unsigned personalityEncoding,
634 const MCSymbol *lsda,
635 unsigned lsdaEncoding) {
636 MCContext &context = streamer.getContext();
637 const TargetAsmInfo &asmInfo = context.getTargetAsmInfo();
638 const MCSection §ion = *asmInfo.getEHFrameSection();
639 streamer.SwitchSection(§ion);
641 MCSymbol *sectionStart;
642 if (asmInfo.isFunctionEHFrameSymbolPrivate())
643 sectionStart = context.CreateTempSymbol();
645 sectionStart = context.GetOrCreateSymbol(Twine("EH_frame") + Twine(CIENum));
649 MCSymbol *sectionEnd = streamer.getContext().CreateTempSymbol();
652 const MCExpr *Length = MakeStartMinusEndExpr(streamer, *sectionStart,
654 streamer.EmitLabel(sectionStart);
655 streamer.EmitAbsValue(Length, 4);
658 streamer.EmitIntValue(0, 4);
661 streamer.EmitIntValue(dwarf::DW_CIE_VERSION, 1);
663 // Augmentation String
664 SmallString<8> Augmentation;
671 streamer.EmitBytes(Augmentation.str(), 0);
672 streamer.EmitIntValue(0, 1);
674 // Code Alignment Factor
675 streamer.EmitULEB128IntValue(1);
677 // Data Alignment Factor
678 streamer.EmitSLEB128IntValue(getDataAlignmentFactor(streamer));
680 // Return Address Register
681 streamer.EmitULEB128IntValue(asmInfo.getDwarfRARegNum(true));
683 // Augmentation Data Length (optional)
684 MCSymbol *augmentationStart = streamer.getContext().CreateTempSymbol();
685 MCSymbol *augmentationEnd = streamer.getContext().CreateTempSymbol();
686 const MCExpr *augmentationLength = MakeStartMinusEndExpr(streamer,
688 *augmentationEnd, 0);
689 streamer.EmitULEB128Value(augmentationLength);
691 // Augmentation Data (optional)
692 streamer.EmitLabel(augmentationStart);
694 // Personality Encoding
695 streamer.EmitIntValue(personalityEncoding, 1);
697 EmitPersonality(streamer, *personality, personalityEncoding);
701 streamer.EmitIntValue(lsdaEncoding, 1);
703 // Encoding of the FDE pointers
704 streamer.EmitIntValue(asmInfo.getFDEEncoding(), 1);
705 streamer.EmitLabel(augmentationEnd);
707 // Initial Instructions
709 const std::vector<MachineMove> Moves = asmInfo.getInitialFrameState();
710 std::vector<MCCFIInstruction> Instructions;
712 for (int i = 0, n = Moves.size(); i != n; ++i) {
713 MCSymbol *Label = Moves[i].getLabel();
714 const MachineLocation &Dst =
715 TranslateMachineLocation(asmInfo, Moves[i].getDestination());
716 const MachineLocation &Src =
717 TranslateMachineLocation(asmInfo, Moves[i].getSource());
718 MCCFIInstruction Inst(Label, Dst, Src);
719 Instructions.push_back(Inst);
722 EmitCFIInstructions(streamer, Instructions, NULL);
725 streamer.EmitValueToAlignment(4);
727 streamer.EmitLabel(sectionEnd);
728 return *sectionStart;
731 MCSymbol *FrameEmitterImpl::EmitFDE(MCStreamer &streamer,
732 const MCSymbol &cieStart,
733 const MCDwarfFrameInfo &frame) {
734 MCContext &context = streamer.getContext();
735 MCSymbol *fdeStart = context.CreateTempSymbol();
736 MCSymbol *fdeEnd = context.CreateTempSymbol();
737 const TargetAsmInfo &asmInfo = context.getTargetAsmInfo();
739 if (!asmInfo.isFunctionEHFrameSymbolPrivate()) {
740 Twine EHName = frame.Function->getName() + Twine(".eh");
741 MCSymbol *EHSym = context.GetOrCreateSymbol(EHName);
742 streamer.EmitEHSymAttributes(frame.Function, EHSym);
743 streamer.EmitLabel(EHSym);
747 const MCExpr *Length = MakeStartMinusEndExpr(streamer, *fdeStart, *fdeEnd, 0);
748 streamer.EmitAbsValue(Length, 4);
750 streamer.EmitLabel(fdeStart);
752 const MCExpr *offset = MakeStartMinusEndExpr(streamer, cieStart, *fdeStart,
754 streamer.EmitAbsValue(offset, 4);
755 unsigned fdeEncoding = asmInfo.getFDEEncoding();
756 unsigned size = getSizeForEncoding(streamer, fdeEncoding);
759 streamer.EmitPCRelSymbolValue(frame.Begin, size);
762 const MCExpr *Range = MakeStartMinusEndExpr(streamer, *frame.Begin,
764 streamer.EmitAbsValue(Range, size);
766 // Augmentation Data Length
767 MCSymbol *augmentationStart = streamer.getContext().CreateTempSymbol();
768 MCSymbol *augmentationEnd = streamer.getContext().CreateTempSymbol();
769 const MCExpr *augmentationLength = MakeStartMinusEndExpr(streamer,
771 *augmentationEnd, 0);
772 streamer.EmitULEB128Value(augmentationLength);
775 streamer.EmitLabel(augmentationStart);
777 EmitSymbol(streamer, *frame.Lsda, frame.LsdaEncoding);
778 streamer.EmitLabel(augmentationEnd);
779 // Call Frame Instructions
781 EmitCFIInstructions(streamer, frame.Instructions, frame.Begin);
784 streamer.EmitValueToAlignment(size);
791 static const CIEKey getEmptyKey() { return CIEKey(0, 0, -1); }
792 static const CIEKey getTombstoneKey() { return CIEKey(0, -1, 0); }
794 CIEKey(const MCSymbol* Personality_, unsigned PersonalityEncoding_,
795 unsigned LsdaEncoding_) : Personality(Personality_),
796 PersonalityEncoding(PersonalityEncoding_),
797 LsdaEncoding(LsdaEncoding_) {
799 const MCSymbol* Personality;
800 unsigned PersonalityEncoding;
801 unsigned LsdaEncoding;
807 struct DenseMapInfo<CIEKey> {
808 static CIEKey getEmptyKey() {
809 return CIEKey::getEmptyKey();
811 static CIEKey getTombstoneKey() {
812 return CIEKey::getTombstoneKey();
814 static unsigned getHashValue(const CIEKey &Key) {
816 ID.AddPointer(Key.Personality);
817 ID.AddInteger(Key.PersonalityEncoding);
818 ID.AddInteger(Key.LsdaEncoding);
819 return ID.ComputeHash();
821 static bool isEqual(const CIEKey &LHS,
823 return LHS.Personality == RHS.Personality &&
824 LHS.PersonalityEncoding == RHS.PersonalityEncoding &&
825 LHS.LsdaEncoding == RHS.LsdaEncoding;
830 void MCDwarfFrameEmitter::Emit(MCStreamer &streamer) {
831 const MCContext &context = streamer.getContext();
832 const TargetAsmInfo &asmInfo = context.getTargetAsmInfo();
833 MCSymbol *fdeEnd = NULL;
834 DenseMap<CIEKey, const MCSymbol*> CIEStarts;
835 FrameEmitterImpl Emitter;
837 for (unsigned i = 0, n = streamer.getNumFrameInfos(); i < n; ++i) {
838 const MCDwarfFrameInfo &frame = streamer.getFrameInfo(i);
839 CIEKey key(frame.Personality, frame.PersonalityEncoding,
841 const MCSymbol *&cieStart = CIEStarts[key];
843 cieStart = &Emitter.EmitCIE(streamer, frame.Personality,
844 frame.PersonalityEncoding, frame.Lsda,
846 fdeEnd = Emitter.EmitFDE(streamer, *cieStart, frame);
848 streamer.EmitLabel(fdeEnd);
851 streamer.EmitValueToAlignment(asmInfo.getPointerSize());
853 streamer.EmitLabel(fdeEnd);
856 void MCDwarfFrameEmitter::EmitAdvanceLoc(MCStreamer &Streamer,
857 uint64_t AddrDelta) {
858 SmallString<256> Tmp;
859 raw_svector_ostream OS(Tmp);
860 const TargetAsmInfo &AsmInfo = Streamer.getContext().getTargetAsmInfo();
861 MCDwarfFrameEmitter::EncodeAdvanceLoc(AddrDelta, OS, AsmInfo);
862 Streamer.EmitBytes(OS.str(), /*AddrSpace=*/0);
865 void MCDwarfFrameEmitter::EncodeAdvanceLoc(uint64_t AddrDelta,
867 const TargetAsmInfo &AsmInfo) {
868 // This is a small hack to facilitate the transition to CFI on OS X. It
869 // relaxes all address advances which lets us produces identical output
870 // to the one produce by CodeGen.
871 const bool Relax = !AsmInfo.isFunctionEHFrameSymbolPrivate();
873 // FIXME: Assumes the code alignment factor is 1.
874 if (AddrDelta == 0) {
875 } else if (isUIntN(6, AddrDelta) && !Relax) {
876 uint8_t Opcode = dwarf::DW_CFA_advance_loc | AddrDelta;
878 } else if (isUInt<8>(AddrDelta) && !Relax) {
879 OS << uint8_t(dwarf::DW_CFA_advance_loc1);
880 OS << uint8_t(AddrDelta);
881 } else if (isUInt<16>(AddrDelta) && !Relax) {
882 // FIXME: check what is the correct behavior on a big endian machine.
883 OS << uint8_t(dwarf::DW_CFA_advance_loc2);
884 OS << uint8_t( AddrDelta & 0xff);
885 OS << uint8_t((AddrDelta >> 8) & 0xff);
887 // FIXME: check what is the correct behavior on a big endian machine.
888 assert(isUInt<32>(AddrDelta));
889 OS << uint8_t(dwarf::DW_CFA_advance_loc4);
890 OS << uint8_t( AddrDelta & 0xff);
891 OS << uint8_t((AddrDelta >> 8) & 0xff);
892 OS << uint8_t((AddrDelta >> 16) & 0xff);
893 OS << uint8_t((AddrDelta >> 24) & 0xff);