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);
357 MCObjectWriter::EncodeULEB128(AddrDelta, OS);
359 OS << char(dwarf::DW_LNS_extended_op);
361 OS << char(dwarf::DW_LNE_end_sequence);
365 // Bias the line delta by the base.
366 Temp = LineDelta - DWARF2_LINE_BASE;
368 // If the line increment is out of range of a special opcode, we must encode
369 // it with DW_LNS_advance_line.
370 if (Temp >= DWARF2_LINE_RANGE) {
371 OS << char(dwarf::DW_LNS_advance_line);
373 raw_svector_ostream OSE(Tmp);
374 MCObjectWriter::EncodeSLEB128(LineDelta, OSE);
378 Temp = 0 - DWARF2_LINE_BASE;
382 // Use DW_LNS_copy instead of a "line +0, addr +0" special opcode.
383 if (LineDelta == 0 && AddrDelta == 0) {
384 OS << char(dwarf::DW_LNS_copy);
388 // Bias the opcode by the special opcode base.
389 Temp += DWARF2_LINE_OPCODE_BASE;
391 // Avoid overflow when addr_delta is large.
392 if (AddrDelta < 256 + MAX_SPECIAL_ADDR_DELTA) {
393 // Try using a special opcode.
394 Opcode = Temp + AddrDelta * DWARF2_LINE_RANGE;
400 // Try using DW_LNS_const_add_pc followed by special op.
401 Opcode = Temp + (AddrDelta - MAX_SPECIAL_ADDR_DELTA) * DWARF2_LINE_RANGE;
403 OS << char(dwarf::DW_LNS_const_add_pc);
409 // Otherwise use DW_LNS_advance_pc.
410 OS << char(dwarf::DW_LNS_advance_pc);
412 raw_svector_ostream OSE(Tmp);
413 MCObjectWriter::EncodeULEB128(AddrDelta, OSE);
417 OS << char(dwarf::DW_LNS_copy);
422 void MCDwarfFile::print(raw_ostream &OS) const {
423 OS << '"' << getName() << '"';
426 void MCDwarfFile::dump() const {
430 static int getDataAlignmentFactor(MCStreamer &streamer) {
431 MCContext &context = streamer.getContext();
432 const TargetAsmInfo &asmInfo = context.getTargetAsmInfo();
433 int size = asmInfo.getPointerSize();
434 if (asmInfo.getStackGrowthDirection() == TargetFrameLowering::StackGrowsUp)
440 static unsigned getSizeForEncoding(MCStreamer &streamer,
441 unsigned symbolEncoding) {
442 MCContext &context = streamer.getContext();
443 const TargetAsmInfo &asmInfo = context.getTargetAsmInfo();
444 unsigned format = symbolEncoding & 0x0f;
447 assert(0 && "Unknown Encoding");
448 case dwarf::DW_EH_PE_absptr:
449 case dwarf::DW_EH_PE_signed:
450 return asmInfo.getPointerSize();
451 case dwarf::DW_EH_PE_udata2:
452 case dwarf::DW_EH_PE_sdata2:
454 case dwarf::DW_EH_PE_udata4:
455 case dwarf::DW_EH_PE_sdata4:
457 case dwarf::DW_EH_PE_udata8:
458 case dwarf::DW_EH_PE_sdata8:
463 static void EmitSymbol(MCStreamer &streamer, const MCSymbol &symbol,
464 unsigned symbolEncoding) {
465 MCContext &context = streamer.getContext();
466 const MCAsmInfo &asmInfo = context.getAsmInfo();
467 const MCExpr *v = asmInfo.getExprForFDESymbol(&symbol,
470 unsigned size = getSizeForEncoding(streamer, symbolEncoding);
471 streamer.EmitAbsValue(v, size);
474 static void EmitPersonality(MCStreamer &streamer, const MCSymbol &symbol,
475 unsigned symbolEncoding) {
476 MCContext &context = streamer.getContext();
477 const MCAsmInfo &asmInfo = context.getAsmInfo();
478 const MCExpr *v = asmInfo.getExprForPersonalitySymbol(&symbol,
481 unsigned size = getSizeForEncoding(streamer, symbolEncoding);
482 streamer.EmitValue(v, size);
485 static const MachineLocation TranslateMachineLocation(
486 const TargetAsmInfo &AsmInfo,
487 const MachineLocation &Loc) {
488 unsigned Reg = Loc.getReg() == MachineLocation::VirtualFP ?
489 MachineLocation::VirtualFP :
490 unsigned(AsmInfo.getDwarfRegNum(Loc.getReg(), true));
491 const MachineLocation &NewLoc = Loc.isReg() ?
492 MachineLocation(Reg) : MachineLocation(Reg, Loc.getOffset());
497 class FrameEmitterImpl {
502 const MCSymbol *SectionStart;
505 FrameEmitterImpl(bool usingCFI, bool isEH, const MCSymbol *sectionStart) :
506 CFAOffset(0), CIENum(0), UsingCFI(usingCFI), IsEH(isEH),
507 SectionStart(sectionStart) {
510 const MCSymbol &EmitCIE(MCStreamer &streamer,
511 const MCSymbol *personality,
512 unsigned personalityEncoding,
513 const MCSymbol *lsda,
514 unsigned lsdaEncoding);
515 MCSymbol *EmitFDE(MCStreamer &streamer,
516 const MCSymbol &cieStart,
517 const MCDwarfFrameInfo &frame);
518 void EmitCFIInstructions(MCStreamer &streamer,
519 const std::vector<MCCFIInstruction> &Instrs,
520 MCSymbol *BaseLabel);
521 void EmitCFIInstruction(MCStreamer &Streamer,
522 const MCCFIInstruction &Instr);
526 void FrameEmitterImpl::EmitCFIInstruction(MCStreamer &Streamer,
527 const MCCFIInstruction &Instr) {
528 int dataAlignmentFactor = getDataAlignmentFactor(Streamer);
530 switch (Instr.getOperation()) {
531 case MCCFIInstruction::Move:
532 case MCCFIInstruction::RelMove: {
533 const MachineLocation &Dst = Instr.getDestination();
534 const MachineLocation &Src = Instr.getSource();
535 const bool IsRelative = Instr.getOperation() == MCCFIInstruction::RelMove;
538 if (Dst.isReg() && Dst.getReg() == MachineLocation::VirtualFP) {
539 if (Src.getReg() == MachineLocation::VirtualFP) {
540 Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa_offset, 1);
542 Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa, 1);
543 Streamer.EmitULEB128IntValue(Src.getReg());
547 CFAOffset += Src.getOffset();
549 CFAOffset = -Src.getOffset();
551 Streamer.EmitULEB128IntValue(CFAOffset);
555 if (Src.isReg() && Src.getReg() == MachineLocation::VirtualFP) {
556 assert(Dst.isReg() && "Machine move not supported yet.");
557 Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa_register, 1);
558 Streamer.EmitULEB128IntValue(Dst.getReg());
562 unsigned Reg = Src.getReg();
564 int Offset = Dst.getOffset();
567 Offset = Offset / dataAlignmentFactor;
570 Streamer.EmitIntValue(dwarf::DW_CFA_offset_extended_sf, 1);
571 Streamer.EmitULEB128IntValue(Reg);
572 Streamer.EmitSLEB128IntValue(Offset);
573 } else if (Reg < 64) {
574 Streamer.EmitIntValue(dwarf::DW_CFA_offset + Reg, 1);
575 Streamer.EmitULEB128IntValue(Offset);
577 Streamer.EmitIntValue(dwarf::DW_CFA_offset_extended, 1);
578 Streamer.EmitULEB128IntValue(Reg);
579 Streamer.EmitULEB128IntValue(Offset);
583 case MCCFIInstruction::Remember:
584 Streamer.EmitIntValue(dwarf::DW_CFA_remember_state, 1);
586 case MCCFIInstruction::Restore:
587 Streamer.EmitIntValue(dwarf::DW_CFA_restore_state, 1);
589 case MCCFIInstruction::SameValue: {
590 unsigned Reg = Instr.getDestination().getReg();
591 Streamer.EmitIntValue(dwarf::DW_CFA_same_value, 1);
592 Streamer.EmitULEB128IntValue(Reg);
596 llvm_unreachable("Unhandled case in switch");
599 /// EmitFrameMoves - Emit frame instructions to describe the layout of the
601 void FrameEmitterImpl::EmitCFIInstructions(MCStreamer &streamer,
602 const std::vector<MCCFIInstruction> &Instrs,
603 MCSymbol *BaseLabel) {
604 for (unsigned i = 0, N = Instrs.size(); i < N; ++i) {
605 const MCCFIInstruction &Instr = Instrs[i];
606 MCSymbol *Label = Instr.getLabel();
607 // Throw out move if the label is invalid.
608 if (Label && !Label->isDefined()) continue; // Not emitted, in dead code.
610 // Advance row if new location.
611 if (BaseLabel && Label) {
612 MCSymbol *ThisSym = Label;
613 if (ThisSym != BaseLabel) {
614 streamer.EmitDwarfAdvanceFrameAddr(BaseLabel, ThisSym);
619 EmitCFIInstruction(streamer, Instr);
623 const MCSymbol &FrameEmitterImpl::EmitCIE(MCStreamer &streamer,
624 const MCSymbol *personality,
625 unsigned personalityEncoding,
626 const MCSymbol *lsda,
627 unsigned lsdaEncoding) {
628 MCContext &context = streamer.getContext();
629 const TargetAsmInfo &asmInfo = context.getTargetAsmInfo();
631 MCSymbol *sectionStart;
632 if (asmInfo.isFunctionEHFrameSymbolPrivate() || !IsEH)
633 sectionStart = context.CreateTempSymbol();
635 sectionStart = context.GetOrCreateSymbol(Twine("EH_frame") + Twine(CIENum));
639 MCSymbol *sectionEnd = streamer.getContext().CreateTempSymbol();
642 const MCExpr *Length = MakeStartMinusEndExpr(streamer, *sectionStart,
644 streamer.EmitLabel(sectionStart);
645 streamer.EmitAbsValue(Length, 4);
648 unsigned CIE_ID = IsEH ? 0 : -1;
649 streamer.EmitIntValue(CIE_ID, 4);
652 streamer.EmitIntValue(dwarf::DW_CIE_VERSION, 1);
654 // Augmentation String
655 SmallString<8> Augmentation;
663 streamer.EmitBytes(Augmentation.str(), 0);
665 streamer.EmitIntValue(0, 1);
667 // Code Alignment Factor
668 streamer.EmitULEB128IntValue(1);
670 // Data Alignment Factor
671 streamer.EmitSLEB128IntValue(getDataAlignmentFactor(streamer));
673 // Return Address Register
674 streamer.EmitULEB128IntValue(asmInfo.getDwarfRARegNum(true));
676 // Augmentation Data Length (optional)
678 unsigned augmentationLength = 0;
681 // Personality Encoding
682 augmentationLength += 1;
684 augmentationLength += getSizeForEncoding(streamer, personalityEncoding);
687 augmentationLength += 1;
688 // Encoding of the FDE pointers
689 augmentationLength += 1;
691 streamer.EmitULEB128IntValue(augmentationLength);
693 // Augmentation Data (optional)
695 // Personality Encoding
696 streamer.EmitIntValue(personalityEncoding, 1);
698 EmitPersonality(streamer, *personality, personalityEncoding);
701 streamer.EmitIntValue(lsdaEncoding, 1); // LSDA Encoding
702 // Encoding of the FDE pointers
703 streamer.EmitIntValue(asmInfo.getFDEEncoding(UsingCFI), 1);
706 // Initial Instructions
708 const std::vector<MachineMove> Moves = asmInfo.getInitialFrameState();
709 std::vector<MCCFIInstruction> Instructions;
711 for (int i = 0, n = Moves.size(); i != n; ++i) {
712 MCSymbol *Label = Moves[i].getLabel();
713 const MachineLocation &Dst =
714 TranslateMachineLocation(asmInfo, Moves[i].getDestination());
715 const MachineLocation &Src =
716 TranslateMachineLocation(asmInfo, Moves[i].getSource());
717 MCCFIInstruction Inst(Label, Dst, Src);
718 Instructions.push_back(Inst);
721 EmitCFIInstructions(streamer, Instructions, NULL);
724 streamer.EmitValueToAlignment(IsEH ? 4 : asmInfo.getPointerSize());
726 streamer.EmitLabel(sectionEnd);
727 return *sectionStart;
730 MCSymbol *FrameEmitterImpl::EmitFDE(MCStreamer &streamer,
731 const MCSymbol &cieStart,
732 const MCDwarfFrameInfo &frame) {
733 MCContext &context = streamer.getContext();
734 MCSymbol *fdeStart = context.CreateTempSymbol();
735 MCSymbol *fdeEnd = context.CreateTempSymbol();
736 const TargetAsmInfo &TAsmInfo = context.getTargetAsmInfo();
738 if (!TAsmInfo.isFunctionEHFrameSymbolPrivate() && IsEH) {
739 MCSymbol *EHSym = context.GetOrCreateSymbol(
740 frame.Function->getName() + Twine(".eh"));
741 streamer.EmitEHSymAttributes(frame.Function, EHSym);
742 streamer.EmitLabel(EHSym);
746 const MCExpr *Length = MakeStartMinusEndExpr(streamer, *fdeStart, *fdeEnd, 0);
747 streamer.EmitAbsValue(Length, 4);
749 streamer.EmitLabel(fdeStart);
752 const MCAsmInfo &asmInfo = context.getAsmInfo();
754 const MCExpr *offset = MakeStartMinusEndExpr(streamer, cieStart, *fdeStart,
756 streamer.EmitAbsValue(offset, 4);
757 } else if (!asmInfo.doesDwarfRequireRelocationForSectionOffset()) {
758 const MCExpr *offset = MakeStartMinusEndExpr(streamer, *SectionStart,
760 streamer.EmitAbsValue(offset, 4);
762 streamer.EmitSymbolValue(&cieStart, 4);
764 unsigned fdeEncoding = TAsmInfo.getFDEEncoding(UsingCFI);
765 unsigned size = getSizeForEncoding(streamer, fdeEncoding);
768 unsigned PCBeginEncoding = IsEH ? fdeEncoding :
769 (unsigned)dwarf::DW_EH_PE_absptr;
770 unsigned PCBeginSize = getSizeForEncoding(streamer, PCBeginEncoding);
771 EmitSymbol(streamer, *frame.Begin, PCBeginEncoding);
774 const MCExpr *Range = MakeStartMinusEndExpr(streamer, *frame.Begin,
776 streamer.EmitAbsValue(Range, size);
779 // Augmentation Data Length
780 unsigned augmentationLength = 0;
783 augmentationLength += getSizeForEncoding(streamer, frame.LsdaEncoding);
785 streamer.EmitULEB128IntValue(augmentationLength);
789 EmitSymbol(streamer, *frame.Lsda, frame.LsdaEncoding);
792 // Call Frame Instructions
794 EmitCFIInstructions(streamer, frame.Instructions, frame.Begin);
797 streamer.EmitValueToAlignment(PCBeginSize);
804 static const CIEKey getEmptyKey() { return CIEKey(0, 0, -1); }
805 static const CIEKey getTombstoneKey() { return CIEKey(0, -1, 0); }
807 CIEKey(const MCSymbol* Personality_, unsigned PersonalityEncoding_,
808 unsigned LsdaEncoding_) : Personality(Personality_),
809 PersonalityEncoding(PersonalityEncoding_),
810 LsdaEncoding(LsdaEncoding_) {
812 const MCSymbol* Personality;
813 unsigned PersonalityEncoding;
814 unsigned LsdaEncoding;
820 struct DenseMapInfo<CIEKey> {
821 static CIEKey getEmptyKey() {
822 return CIEKey::getEmptyKey();
824 static CIEKey getTombstoneKey() {
825 return CIEKey::getTombstoneKey();
827 static unsigned getHashValue(const CIEKey &Key) {
829 ID.AddPointer(Key.Personality);
830 ID.AddInteger(Key.PersonalityEncoding);
831 ID.AddInteger(Key.LsdaEncoding);
832 return ID.ComputeHash();
834 static bool isEqual(const CIEKey &LHS,
836 return LHS.Personality == RHS.Personality &&
837 LHS.PersonalityEncoding == RHS.PersonalityEncoding &&
838 LHS.LsdaEncoding == RHS.LsdaEncoding;
843 void MCDwarfFrameEmitter::Emit(MCStreamer &streamer,
846 MCContext &context = streamer.getContext();
847 const TargetAsmInfo &asmInfo = context.getTargetAsmInfo();
848 const MCSection §ion = isEH ?
849 *asmInfo.getEHFrameSection() : *asmInfo.getDwarfFrameSection();
850 streamer.SwitchSection(§ion);
851 MCSymbol *SectionStart = context.CreateTempSymbol();
852 streamer.EmitLabel(SectionStart);
854 MCSymbol *fdeEnd = NULL;
855 DenseMap<CIEKey, const MCSymbol*> CIEStarts;
856 FrameEmitterImpl Emitter(usingCFI, isEH, SectionStart);
858 const MCSymbol *DummyDebugKey = NULL;
859 for (unsigned i = 0, n = streamer.getNumFrameInfos(); i < n; ++i) {
860 const MCDwarfFrameInfo &frame = streamer.getFrameInfo(i);
861 CIEKey key(frame.Personality, frame.PersonalityEncoding,
863 const MCSymbol *&cieStart = isEH ? CIEStarts[key] : DummyDebugKey;
865 cieStart = &Emitter.EmitCIE(streamer, frame.Personality,
866 frame.PersonalityEncoding, frame.Lsda,
868 fdeEnd = Emitter.EmitFDE(streamer, *cieStart, frame);
870 streamer.EmitLabel(fdeEnd);
873 streamer.EmitValueToAlignment(asmInfo.getPointerSize());
875 streamer.EmitLabel(fdeEnd);
878 void MCDwarfFrameEmitter::EmitAdvanceLoc(MCStreamer &Streamer,
879 uint64_t AddrDelta) {
880 SmallString<256> Tmp;
881 raw_svector_ostream OS(Tmp);
882 MCDwarfFrameEmitter::EncodeAdvanceLoc(AddrDelta, OS);
883 Streamer.EmitBytes(OS.str(), /*AddrSpace=*/0);
886 void MCDwarfFrameEmitter::EncodeAdvanceLoc(uint64_t AddrDelta,
888 // FIXME: Assumes the code alignment factor is 1.
889 if (AddrDelta == 0) {
890 } else if (isUIntN(6, AddrDelta)) {
891 uint8_t Opcode = dwarf::DW_CFA_advance_loc | AddrDelta;
893 } else if (isUInt<8>(AddrDelta)) {
894 OS << uint8_t(dwarf::DW_CFA_advance_loc1);
895 OS << uint8_t(AddrDelta);
896 } else if (isUInt<16>(AddrDelta)) {
897 // FIXME: check what is the correct behavior on a big endian machine.
898 OS << uint8_t(dwarf::DW_CFA_advance_loc2);
899 OS << uint8_t( AddrDelta & 0xff);
900 OS << uint8_t((AddrDelta >> 8) & 0xff);
902 // FIXME: check what is the correct behavior on a big endian machine.
903 assert(isUInt<32>(AddrDelta));
904 OS << uint8_t(dwarf::DW_CFA_advance_loc4);
905 OS << uint8_t( AddrDelta & 0xff);
906 OS << uint8_t((AddrDelta >> 8) & 0xff);
907 OS << uint8_t((AddrDelta >> 16) & 0xff);
908 OS << uint8_t((AddrDelta >> 24) & 0xff);