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/MC/MCDwarf.h"
11 #include "llvm/MC/MCAsmInfo.h"
12 #include "llvm/MC/MCContext.h"
13 #include "llvm/MC/MCObjectFileInfo.h"
14 #include "llvm/MC/MCObjectWriter.h"
15 #include "llvm/MC/MCRegisterInfo.h"
16 #include "llvm/MC/MCStreamer.h"
17 #include "llvm/MC/MCSymbol.h"
18 #include "llvm/MC/MCExpr.h"
19 #include "llvm/Support/Debug.h"
20 #include "llvm/Support/ErrorHandling.h"
21 #include "llvm/Support/raw_ostream.h"
22 #include "llvm/ADT/FoldingSet.h"
23 #include "llvm/ADT/SmallString.h"
24 #include "llvm/ADT/StringExtras.h"
25 #include "llvm/ADT/Twine.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) {
54 if (DWARF2_LINE_MIN_INSN_LENGTH == 1)
56 if (AddrDelta % DWARF2_LINE_MIN_INSN_LENGTH != 0) {
57 // TODO: report this error, but really only once.
60 return AddrDelta / DWARF2_LINE_MIN_INSN_LENGTH;
64 // This is called when an instruction is assembled into the specified section
65 // and if there is information from the last .loc directive that has yet to have
66 // a line entry made for it is made.
68 void MCLineEntry::Make(MCStreamer *MCOS, const MCSection *Section) {
69 if (!MCOS->getContext().getDwarfLocSeen())
72 // Create a symbol at in the current section for use in the line entry.
73 MCSymbol *LineSym = MCOS->getContext().CreateTempSymbol();
74 // Set the value of the symbol to use for the MCLineEntry.
75 MCOS->EmitLabel(LineSym);
77 // Get the current .loc info saved in the context.
78 const MCDwarfLoc &DwarfLoc = MCOS->getContext().getCurrentDwarfLoc();
80 // Create a (local) line entry with the symbol and the current .loc info.
81 MCLineEntry LineEntry(LineSym, DwarfLoc);
83 // clear DwarfLocSeen saying the current .loc info is now used.
84 MCOS->getContext().ClearDwarfLocSeen();
86 // Get the MCLineSection for this section, if one does not exist for this
88 const DenseMap<const MCSection *, MCLineSection *> &MCLineSections =
89 MCOS->getContext().getMCLineSections();
90 MCLineSection *LineSection = MCLineSections.lookup(Section);
92 // Create a new MCLineSection. This will be deleted after the dwarf line
93 // table is created using it by iterating through the MCLineSections
95 LineSection = new MCLineSection;
96 // Save a pointer to the new LineSection into the MCLineSections DenseMap.
97 MCOS->getContext().addMCLineSection(Section, LineSection);
100 // Add the line entry to this section's entries.
101 LineSection->addLineEntry(LineEntry);
105 // This helper routine returns an expression of End - Start + IntVal .
107 static inline const MCExpr *MakeStartMinusEndExpr(const MCStreamer &MCOS,
108 const MCSymbol &Start,
111 MCSymbolRefExpr::VariantKind Variant = MCSymbolRefExpr::VK_None;
113 MCSymbolRefExpr::Create(&End, Variant, MCOS.getContext());
115 MCSymbolRefExpr::Create(&Start, Variant, MCOS.getContext());
117 MCBinaryExpr::Create(MCBinaryExpr::Sub, Res, RHS, MCOS.getContext());
119 MCConstantExpr::Create(IntVal, MCOS.getContext());
121 MCBinaryExpr::Create(MCBinaryExpr::Sub, Res1, Res2, MCOS.getContext());
126 // This emits the Dwarf line table for the specified section from the entries
127 // in the LineSection.
129 static inline void EmitDwarfLineTable(MCStreamer *MCOS,
130 const MCSection *Section,
131 const MCLineSection *LineSection) {
132 unsigned FileNum = 1;
133 unsigned LastLine = 1;
135 unsigned Flags = DWARF2_LINE_DEFAULT_IS_STMT ? DWARF2_FLAG_IS_STMT : 0;
137 MCSymbol *LastLabel = NULL;
139 // Loop through each MCLineEntry and encode the dwarf line number table.
140 for (MCLineSection::const_iterator
141 it = LineSection->getMCLineEntries()->begin(),
142 ie = LineSection->getMCLineEntries()->end(); it != ie; ++it) {
144 if (FileNum != it->getFileNum()) {
145 FileNum = it->getFileNum();
146 MCOS->EmitIntValue(dwarf::DW_LNS_set_file, 1);
147 MCOS->EmitULEB128IntValue(FileNum);
149 if (Column != it->getColumn()) {
150 Column = it->getColumn();
151 MCOS->EmitIntValue(dwarf::DW_LNS_set_column, 1);
152 MCOS->EmitULEB128IntValue(Column);
154 if (Isa != it->getIsa()) {
156 MCOS->EmitIntValue(dwarf::DW_LNS_set_isa, 1);
157 MCOS->EmitULEB128IntValue(Isa);
159 if ((it->getFlags() ^ Flags) & DWARF2_FLAG_IS_STMT) {
160 Flags = it->getFlags();
161 MCOS->EmitIntValue(dwarf::DW_LNS_negate_stmt, 1);
163 if (it->getFlags() & DWARF2_FLAG_BASIC_BLOCK)
164 MCOS->EmitIntValue(dwarf::DW_LNS_set_basic_block, 1);
165 if (it->getFlags() & DWARF2_FLAG_PROLOGUE_END)
166 MCOS->EmitIntValue(dwarf::DW_LNS_set_prologue_end, 1);
167 if (it->getFlags() & DWARF2_FLAG_EPILOGUE_BEGIN)
168 MCOS->EmitIntValue(dwarf::DW_LNS_set_epilogue_begin, 1);
170 int64_t LineDelta = static_cast<int64_t>(it->getLine()) - LastLine;
171 MCSymbol *Label = it->getLabel();
173 // At this point we want to emit/create the sequence to encode the delta in
174 // line numbers and the increment of the address from the previous Label
175 // and the current Label.
176 const MCAsmInfo &asmInfo = MCOS->getContext().getAsmInfo();
177 MCOS->EmitDwarfAdvanceLineAddr(LineDelta, LastLabel, Label,
178 asmInfo.getPointerSize());
180 LastLine = it->getLine();
184 // Emit a DW_LNE_end_sequence for the end of the section.
185 // Using the pointer Section create a temporary label at the end of the
186 // section and use that and the LastLabel to compute the address delta
187 // and use INT64_MAX as the line delta which is the signal that this is
188 // actually a DW_LNE_end_sequence.
190 // Switch to the section to be able to create a symbol at its end.
191 MCOS->SwitchSection(Section);
193 MCContext &context = MCOS->getContext();
194 // Create a symbol at the end of the section.
195 MCSymbol *SectionEnd = context.CreateTempSymbol();
196 // Set the value of the symbol, as we are at the end of the section.
197 MCOS->EmitLabel(SectionEnd);
199 // Switch back the the dwarf line section.
200 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfLineSection());
202 const MCAsmInfo &asmInfo = MCOS->getContext().getAsmInfo();
203 MCOS->EmitDwarfAdvanceLineAddr(INT64_MAX, LastLabel, SectionEnd,
204 asmInfo.getPointerSize());
208 // This emits the Dwarf file and the line tables.
210 void MCDwarfFileTable::Emit(MCStreamer *MCOS) {
211 MCContext &context = MCOS->getContext();
212 // Switch to the section where the table will be emitted into.
213 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfLineSection());
215 // Create a symbol at the beginning of this section.
216 MCSymbol *LineStartSym = context.CreateTempSymbol();
217 // Set the value of the symbol, as we are at the start of the section.
218 MCOS->EmitLabel(LineStartSym);
220 // Create a symbol for the end of the section (to be set when we get there).
221 MCSymbol *LineEndSym = context.CreateTempSymbol();
223 // The first 4 bytes is the total length of the information for this
224 // compilation unit (not including these 4 bytes for the length).
225 MCOS->EmitAbsValue(MakeStartMinusEndExpr(*MCOS, *LineStartSym, *LineEndSym,4),
228 // Next 2 bytes is the Version, which is Dwarf 2.
229 MCOS->EmitIntValue(2, 2);
231 // Create a symbol for the end of the prologue (to be set when we get there).
232 MCSymbol *ProEndSym = context.CreateTempSymbol(); // Lprologue_end
234 // Length of the prologue, is the next 4 bytes. Which is the start of the
235 // section to the end of the prologue. Not including the 4 bytes for the
236 // total length, the 2 bytes for the version, and these 4 bytes for the
237 // length of the prologue.
238 MCOS->EmitAbsValue(MakeStartMinusEndExpr(*MCOS, *LineStartSym, *ProEndSym,
242 // Parameters of the state machine, are next.
243 MCOS->EmitIntValue(DWARF2_LINE_MIN_INSN_LENGTH, 1);
244 MCOS->EmitIntValue(DWARF2_LINE_DEFAULT_IS_STMT, 1);
245 MCOS->EmitIntValue(DWARF2_LINE_BASE, 1);
246 MCOS->EmitIntValue(DWARF2_LINE_RANGE, 1);
247 MCOS->EmitIntValue(DWARF2_LINE_OPCODE_BASE, 1);
249 // Standard opcode lengths
250 MCOS->EmitIntValue(0, 1); // length of DW_LNS_copy
251 MCOS->EmitIntValue(1, 1); // length of DW_LNS_advance_pc
252 MCOS->EmitIntValue(1, 1); // length of DW_LNS_advance_line
253 MCOS->EmitIntValue(1, 1); // length of DW_LNS_set_file
254 MCOS->EmitIntValue(1, 1); // length of DW_LNS_set_column
255 MCOS->EmitIntValue(0, 1); // length of DW_LNS_negate_stmt
256 MCOS->EmitIntValue(0, 1); // length of DW_LNS_set_basic_block
257 MCOS->EmitIntValue(0, 1); // length of DW_LNS_const_add_pc
258 MCOS->EmitIntValue(1, 1); // length of DW_LNS_fixed_advance_pc
259 MCOS->EmitIntValue(0, 1); // length of DW_LNS_set_prologue_end
260 MCOS->EmitIntValue(0, 1); // length of DW_LNS_set_epilogue_begin
261 MCOS->EmitIntValue(1, 1); // DW_LNS_set_isa
263 // Put out the directory and file tables.
265 // First the directory table.
266 const std::vector<StringRef> &MCDwarfDirs =
267 context.getMCDwarfDirs();
268 for (unsigned i = 0; i < MCDwarfDirs.size(); i++) {
269 MCOS->EmitBytes(MCDwarfDirs[i], 0); // the DirectoryName
270 MCOS->EmitBytes(StringRef("\0", 1), 0); // the null term. of the string
272 MCOS->EmitIntValue(0, 1); // Terminate the directory list
274 // Second the file table.
275 const std::vector<MCDwarfFile *> &MCDwarfFiles =
276 MCOS->getContext().getMCDwarfFiles();
277 for (unsigned i = 1; i < MCDwarfFiles.size(); i++) {
278 MCOS->EmitBytes(MCDwarfFiles[i]->getName(), 0); // FileName
279 MCOS->EmitBytes(StringRef("\0", 1), 0); // the null term. of the string
281 MCOS->EmitULEB128IntValue(MCDwarfFiles[i]->getDirIndex());
282 MCOS->EmitIntValue(0, 1); // last modification timestamp (always 0)
283 MCOS->EmitIntValue(0, 1); // filesize (always 0)
285 MCOS->EmitIntValue(0, 1); // Terminate the file list
287 // This is the end of the prologue, so set the value of the symbol at the
288 // end of the prologue (that was used in a previous expression).
289 MCOS->EmitLabel(ProEndSym);
291 // Put out the line tables.
292 const DenseMap<const MCSection *, MCLineSection *> &MCLineSections =
293 MCOS->getContext().getMCLineSections();
294 const std::vector<const MCSection *> &MCLineSectionOrder =
295 MCOS->getContext().getMCLineSectionOrder();
296 for (std::vector<const MCSection*>::const_iterator it =
297 MCLineSectionOrder.begin(), ie = MCLineSectionOrder.end(); it != ie;
299 const MCSection *Sec = *it;
300 const MCLineSection *Line = MCLineSections.lookup(Sec);
301 EmitDwarfLineTable(MCOS, Sec, Line);
303 // Now delete the MCLineSections that were created in MCLineEntry::Make()
304 // and used to emit the line table.
308 if (MCOS->getContext().getAsmInfo().getLinkerRequiresNonEmptyDwarfLines()
309 && MCLineSectionOrder.begin() == MCLineSectionOrder.end()) {
310 // The darwin9 linker has a bug (see PR8715). For for 32-bit architectures
312 // total_length >= prologue_length + 10
313 // We are 4 bytes short, since we have total_length = 51 and
314 // prologue_length = 45
316 // The regular end_sequence should be sufficient.
317 MCDwarfLineAddr::Emit(MCOS, INT64_MAX, 0);
320 // This is the end of the section, so set the value of the symbol at the end
321 // of this section (that was used in a previous expression).
322 MCOS->EmitLabel(LineEndSym);
325 /// Utility function to write the encoding to an object writer.
326 void MCDwarfLineAddr::Write(MCObjectWriter *OW, int64_t LineDelta,
327 uint64_t AddrDelta) {
328 SmallString<256> Tmp;
329 raw_svector_ostream OS(Tmp);
330 MCDwarfLineAddr::Encode(LineDelta, AddrDelta, OS);
331 OW->WriteBytes(OS.str());
334 /// Utility function to emit the encoding to a streamer.
335 void MCDwarfLineAddr::Emit(MCStreamer *MCOS, int64_t LineDelta,
336 uint64_t AddrDelta) {
337 SmallString<256> Tmp;
338 raw_svector_ostream OS(Tmp);
339 MCDwarfLineAddr::Encode(LineDelta, AddrDelta, OS);
340 MCOS->EmitBytes(OS.str(), /*AddrSpace=*/0);
343 /// Utility function to encode a Dwarf pair of LineDelta and AddrDeltas.
344 void MCDwarfLineAddr::Encode(int64_t LineDelta, uint64_t AddrDelta,
346 uint64_t Temp, Opcode;
347 bool NeedCopy = false;
349 // Scale the address delta by the minimum instruction length.
350 AddrDelta = ScaleAddrDelta(AddrDelta);
352 // A LineDelta of INT64_MAX is a signal that this is actually a
353 // DW_LNE_end_sequence. We cannot use special opcodes here, since we want the
354 // end_sequence to emit the matrix entry.
355 if (LineDelta == INT64_MAX) {
356 if (AddrDelta == MAX_SPECIAL_ADDR_DELTA)
357 OS << char(dwarf::DW_LNS_const_add_pc);
359 OS << char(dwarf::DW_LNS_advance_pc);
360 MCObjectWriter::EncodeULEB128(AddrDelta, OS);
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 MCAsmInfo &asmInfo = context.getAsmInfo();
436 int size = asmInfo.getPointerSize();
437 if (asmInfo.isStackGrowthDirectionUp())
443 static unsigned getSizeForEncoding(MCStreamer &streamer,
444 unsigned symbolEncoding) {
445 MCContext &context = streamer.getContext();
446 unsigned format = symbolEncoding & 0x0f;
449 assert(0 && "Unknown Encoding");
450 case dwarf::DW_EH_PE_absptr:
451 case dwarf::DW_EH_PE_signed:
452 return context.getAsmInfo().getPointerSize();
453 case dwarf::DW_EH_PE_udata2:
454 case dwarf::DW_EH_PE_sdata2:
456 case dwarf::DW_EH_PE_udata4:
457 case dwarf::DW_EH_PE_sdata4:
459 case dwarf::DW_EH_PE_udata8:
460 case dwarf::DW_EH_PE_sdata8:
465 static void EmitSymbol(MCStreamer &streamer, const MCSymbol &symbol,
466 unsigned symbolEncoding, const char *comment = 0) {
467 MCContext &context = streamer.getContext();
468 const MCAsmInfo &asmInfo = context.getAsmInfo();
469 const MCExpr *v = asmInfo.getExprForFDESymbol(&symbol,
472 unsigned size = getSizeForEncoding(streamer, symbolEncoding);
473 if (streamer.isVerboseAsm() && comment) streamer.AddComment(comment);
474 streamer.EmitAbsValue(v, size);
477 static void EmitPersonality(MCStreamer &streamer, const MCSymbol &symbol,
478 unsigned symbolEncoding) {
479 MCContext &context = streamer.getContext();
480 const MCAsmInfo &asmInfo = context.getAsmInfo();
481 const MCExpr *v = asmInfo.getExprForPersonalitySymbol(&symbol,
484 unsigned size = getSizeForEncoding(streamer, symbolEncoding);
485 streamer.EmitValue(v, size);
488 static const MachineLocation TranslateMachineLocation(
489 const MCRegisterInfo &MRI,
490 const MachineLocation &Loc) {
491 unsigned Reg = Loc.getReg() == MachineLocation::VirtualFP ?
492 MachineLocation::VirtualFP :
493 unsigned(MRI.getDwarfRegNum(Loc.getReg(), true));
494 const MachineLocation &NewLoc = Loc.isReg() ?
495 MachineLocation(Reg) : MachineLocation(Reg, Loc.getOffset());
500 class FrameEmitterImpl {
505 const MCSymbol *SectionStart;
507 FrameEmitterImpl(bool usingCFI, bool isEH)
508 : CFAOffset(0), CIENum(0), UsingCFI(usingCFI), IsEH(isEH),
511 void setSectionStart(const MCSymbol *Label) { SectionStart = Label; }
513 /// EmitCompactUnwind - Emit the unwind information in a compact way. If
514 /// we're successful, return 'true'. Otherwise, return 'false' and it will
515 /// emit the normal CIE and FDE.
516 bool EmitCompactUnwind(MCStreamer &streamer,
517 const MCDwarfFrameInfo &frame);
519 const MCSymbol &EmitCIE(MCStreamer &streamer,
520 const MCSymbol *personality,
521 unsigned personalityEncoding,
522 const MCSymbol *lsda,
523 unsigned lsdaEncoding);
524 MCSymbol *EmitFDE(MCStreamer &streamer,
525 const MCSymbol &cieStart,
526 const MCDwarfFrameInfo &frame);
527 void EmitCFIInstructions(MCStreamer &streamer,
528 const std::vector<MCCFIInstruction> &Instrs,
529 MCSymbol *BaseLabel);
530 void EmitCFIInstruction(MCStreamer &Streamer,
531 const MCCFIInstruction &Instr);
534 } // end anonymous namespace
536 static void EmitEncodingByte(MCStreamer &Streamer, unsigned Encoding,
538 if (Streamer.isVerboseAsm()) {
539 const char *EncStr = 0;
541 default: EncStr = "<unknown encoding>";
542 case dwarf::DW_EH_PE_absptr: EncStr = "absptr";
543 case dwarf::DW_EH_PE_omit: EncStr = "omit";
544 case dwarf::DW_EH_PE_pcrel: EncStr = "pcrel";
545 case dwarf::DW_EH_PE_udata4: EncStr = "udata4";
546 case dwarf::DW_EH_PE_udata8: EncStr = "udata8";
547 case dwarf::DW_EH_PE_sdata4: EncStr = "sdata4";
548 case dwarf::DW_EH_PE_sdata8: EncStr = "sdata8";
549 case dwarf::DW_EH_PE_pcrel |dwarf::DW_EH_PE_udata4: EncStr = "pcrel udata4";
550 case dwarf::DW_EH_PE_pcrel |dwarf::DW_EH_PE_sdata4: EncStr = "pcrel sdata4";
551 case dwarf::DW_EH_PE_pcrel |dwarf::DW_EH_PE_udata8: EncStr = "pcrel udata8";
552 case dwarf::DW_EH_PE_pcrel |dwarf::DW_EH_PE_sdata8: EncStr = "pcrel sdata8";
553 case dwarf::DW_EH_PE_indirect |dwarf::DW_EH_PE_pcrel|dwarf::DW_EH_PE_udata4:
554 EncStr = "indirect pcrel udata4";
555 case dwarf::DW_EH_PE_indirect |dwarf::DW_EH_PE_pcrel|dwarf::DW_EH_PE_sdata4:
556 EncStr = "indirect pcrel sdata4";
557 case dwarf::DW_EH_PE_indirect |dwarf::DW_EH_PE_pcrel|dwarf::DW_EH_PE_udata8:
558 EncStr = "indirect pcrel udata8";
559 case dwarf::DW_EH_PE_indirect |dwarf::DW_EH_PE_pcrel|dwarf::DW_EH_PE_sdata8:
560 EncStr = "indirect pcrel sdata8";
563 Streamer.AddComment(Twine(Prefix) + " = " + EncStr);
566 Streamer.EmitIntValue(Encoding, 1);
569 void FrameEmitterImpl::EmitCFIInstruction(MCStreamer &Streamer,
570 const MCCFIInstruction &Instr) {
571 int dataAlignmentFactor = getDataAlignmentFactor(Streamer);
572 bool VerboseAsm = Streamer.isVerboseAsm();
574 switch (Instr.getOperation()) {
575 case MCCFIInstruction::Move:
576 case MCCFIInstruction::RelMove: {
577 const MachineLocation &Dst = Instr.getDestination();
578 const MachineLocation &Src = Instr.getSource();
579 const bool IsRelative = Instr.getOperation() == MCCFIInstruction::RelMove;
582 if (Dst.isReg() && Dst.getReg() == MachineLocation::VirtualFP) {
583 if (Src.getReg() == MachineLocation::VirtualFP) {
584 if (VerboseAsm) Streamer.AddComment("DW_CFA_def_cfa_offset");
585 Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa_offset, 1);
587 if (VerboseAsm) Streamer.AddComment("DW_CFA_def_cfa");
588 Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa, 1);
589 if (VerboseAsm) Streamer.AddComment(Twine("Reg ") +
590 Twine(Src.getReg()));
591 Streamer.EmitULEB128IntValue(Src.getReg());
595 CFAOffset += Src.getOffset();
597 CFAOffset = -Src.getOffset();
599 if (VerboseAsm) Streamer.AddComment(Twine("Offset " + Twine(CFAOffset)));
600 Streamer.EmitULEB128IntValue(CFAOffset);
604 if (Src.isReg() && Src.getReg() == MachineLocation::VirtualFP) {
605 assert(Dst.isReg() && "Machine move not supported yet.");
606 if (VerboseAsm) Streamer.AddComment("DW_CFA_def_cfa_register");
607 Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa_register, 1);
608 if (VerboseAsm) Streamer.AddComment(Twine("Reg ") + Twine(Dst.getReg()));
609 Streamer.EmitULEB128IntValue(Dst.getReg());
613 unsigned Reg = Src.getReg();
614 int Offset = Dst.getOffset();
617 Offset = Offset / dataAlignmentFactor;
620 if (VerboseAsm) Streamer.AddComment("DW_CFA_offset_extended_sf");
621 Streamer.EmitIntValue(dwarf::DW_CFA_offset_extended_sf, 1);
622 if (VerboseAsm) Streamer.AddComment(Twine("Reg ") + Twine(Reg));
623 Streamer.EmitULEB128IntValue(Reg);
624 if (VerboseAsm) Streamer.AddComment(Twine("Offset ") + Twine(Offset));
625 Streamer.EmitSLEB128IntValue(Offset);
626 } else if (Reg < 64) {
627 if (VerboseAsm) Streamer.AddComment(Twine("DW_CFA_offset + Reg(") +
629 Streamer.EmitIntValue(dwarf::DW_CFA_offset + Reg, 1);
630 if (VerboseAsm) Streamer.AddComment(Twine("Offset ") + Twine(Offset));
631 Streamer.EmitULEB128IntValue(Offset);
633 if (VerboseAsm) Streamer.AddComment("DW_CFA_offset_extended");
634 Streamer.EmitIntValue(dwarf::DW_CFA_offset_extended, 1);
635 if (VerboseAsm) Streamer.AddComment(Twine("Reg ") + Twine(Reg));
636 Streamer.EmitULEB128IntValue(Reg);
637 if (VerboseAsm) Streamer.AddComment(Twine("Offset ") + Twine(Offset));
638 Streamer.EmitULEB128IntValue(Offset);
642 case MCCFIInstruction::Remember:
643 if (VerboseAsm) Streamer.AddComment("DW_CFA_remember_state");
644 Streamer.EmitIntValue(dwarf::DW_CFA_remember_state, 1);
646 case MCCFIInstruction::Restore:
647 if (VerboseAsm) Streamer.AddComment("DW_CFA_restore_state");
648 Streamer.EmitIntValue(dwarf::DW_CFA_restore_state, 1);
650 case MCCFIInstruction::SameValue: {
651 unsigned Reg = Instr.getDestination().getReg();
652 if (VerboseAsm) Streamer.AddComment("DW_CFA_same_value");
653 Streamer.EmitIntValue(dwarf::DW_CFA_same_value, 1);
654 if (VerboseAsm) Streamer.AddComment(Twine("Reg ") + Twine(Reg));
655 Streamer.EmitULEB128IntValue(Reg);
659 llvm_unreachable("Unhandled case in switch");
662 /// EmitFrameMoves - Emit frame instructions to describe the layout of the
664 void FrameEmitterImpl::EmitCFIInstructions(MCStreamer &streamer,
665 const std::vector<MCCFIInstruction> &Instrs,
666 MCSymbol *BaseLabel) {
667 for (unsigned i = 0, N = Instrs.size(); i < N; ++i) {
668 const MCCFIInstruction &Instr = Instrs[i];
669 MCSymbol *Label = Instr.getLabel();
670 // Throw out move if the label is invalid.
671 if (Label && !Label->isDefined()) continue; // Not emitted, in dead code.
673 // Advance row if new location.
674 if (BaseLabel && Label) {
675 MCSymbol *ThisSym = Label;
676 if (ThisSym != BaseLabel) {
677 if (streamer.isVerboseAsm()) streamer.AddComment("DW_CFA_advance_loc4");
678 streamer.EmitDwarfAdvanceFrameAddr(BaseLabel, ThisSym);
683 EmitCFIInstruction(streamer, Instr);
687 /// EmitCompactUnwind - Emit the unwind information in a compact way. If we're
688 /// successful, return 'true'. Otherwise, return 'false' and it will emit the
689 /// normal CIE and FDE.
690 bool FrameEmitterImpl::EmitCompactUnwind(MCStreamer &Streamer,
691 const MCDwarfFrameInfo &Frame) {
692 MCContext &Context = Streamer.getContext();
693 const MCObjectFileInfo *MOFI = Context.getObjectFileInfo();
694 bool VerboseAsm = Streamer.isVerboseAsm();
696 // range-start range-length compact-unwind-enc personality-func lsda
697 // _foo LfooEnd-_foo 0x00000023 0 0
698 // _bar LbarEnd-_bar 0x00000025 __gxx_personality except_tab1
700 // .section __LD,__compact_unwind,regular,debug
702 // # compact unwind for _foo
704 // .set L1,LfooEnd-_foo
710 // # compact unwind for _bar
712 // .set L2,LbarEnd-_bar
715 // .quad __gxx_personality
718 uint32_t Encoding = Frame.CompactUnwindEncoding;
719 if (!Encoding) return false;
721 // The encoding needs to know we have an LSDA.
723 Encoding |= 0x40000000;
725 Streamer.SwitchSection(MOFI->getCompactUnwindSection());
728 unsigned FDEEncoding = MOFI->getFDEEncoding(UsingCFI);
729 unsigned Size = getSizeForEncoding(Streamer, FDEEncoding);
730 if (VerboseAsm) Streamer.AddComment("Range Start");
731 Streamer.EmitSymbolValue(Frame.Function, Size);
734 const MCExpr *Range = MakeStartMinusEndExpr(Streamer, *Frame.Begin,
736 if (VerboseAsm) Streamer.AddComment("Range Length");
737 Streamer.EmitAbsValue(Range, 4);
740 Size = getSizeForEncoding(Streamer, dwarf::DW_EH_PE_udata4);
741 if (VerboseAsm) Streamer.AddComment(Twine("Compact Unwind Encoding: 0x") +
742 Twine(llvm::utohexstr(Encoding)));
743 Streamer.EmitIntValue(Encoding, Size);
746 // Personality Function
747 Size = getSizeForEncoding(Streamer, dwarf::DW_EH_PE_absptr);
748 if (VerboseAsm) Streamer.AddComment("Personality Function");
749 if (Frame.Personality)
750 Streamer.EmitSymbolValue(Frame.Personality, Size);
752 Streamer.EmitIntValue(0, Size); // No personality fn
755 Size = getSizeForEncoding(Streamer, Frame.LsdaEncoding);
756 if (VerboseAsm) Streamer.AddComment("LSDA");
758 Streamer.EmitSymbolValue(Frame.Lsda, Size);
760 Streamer.EmitIntValue(0, Size); // No LSDA
765 const MCSymbol &FrameEmitterImpl::EmitCIE(MCStreamer &streamer,
766 const MCSymbol *personality,
767 unsigned personalityEncoding,
768 const MCSymbol *lsda,
769 unsigned lsdaEncoding) {
770 MCContext &context = streamer.getContext();
771 const MCRegisterInfo &MRI = context.getRegisterInfo();
772 const MCObjectFileInfo *MOFI = context.getObjectFileInfo();
773 bool verboseAsm = streamer.isVerboseAsm();
775 MCSymbol *sectionStart;
776 if (MOFI->isFunctionEHFrameSymbolPrivate() || !IsEH)
777 sectionStart = context.CreateTempSymbol();
779 sectionStart = context.GetOrCreateSymbol(Twine("EH_frame") + Twine(CIENum));
781 streamer.EmitLabel(sectionStart);
784 MCSymbol *sectionEnd = context.CreateTempSymbol();
787 const MCExpr *Length = MakeStartMinusEndExpr(streamer, *sectionStart,
789 if (verboseAsm) streamer.AddComment("CIE Length");
790 streamer.EmitAbsValue(Length, 4);
793 unsigned CIE_ID = IsEH ? 0 : -1;
794 if (verboseAsm) streamer.AddComment("CIE ID Tag");
795 streamer.EmitIntValue(CIE_ID, 4);
798 if (verboseAsm) streamer.AddComment("DW_CIE_VERSION");
799 streamer.EmitIntValue(dwarf::DW_CIE_VERSION, 1);
801 // Augmentation String
802 SmallString<8> Augmentation;
804 if (verboseAsm) streamer.AddComment("CIE Augmentation");
811 streamer.EmitBytes(Augmentation.str(), 0);
813 streamer.EmitIntValue(0, 1);
815 // Code Alignment Factor
816 if (verboseAsm) streamer.AddComment("CIE Code Alignment Factor");
817 streamer.EmitULEB128IntValue(1);
819 // Data Alignment Factor
820 if (verboseAsm) streamer.AddComment("CIE Data Alignment Factor");
821 streamer.EmitSLEB128IntValue(getDataAlignmentFactor(streamer));
823 // Return Address Register
824 if (verboseAsm) streamer.AddComment("CIE Return Address Column");
825 streamer.EmitULEB128IntValue(MRI.getDwarfRegNum(MRI.getRARegister(), true));
827 // Augmentation Data Length (optional)
829 unsigned augmentationLength = 0;
832 // Personality Encoding
833 augmentationLength += 1;
835 augmentationLength += getSizeForEncoding(streamer, personalityEncoding);
838 augmentationLength += 1;
839 // Encoding of the FDE pointers
840 augmentationLength += 1;
842 if (verboseAsm) streamer.AddComment("Augmentation Size");
843 streamer.EmitULEB128IntValue(augmentationLength);
845 // Augmentation Data (optional)
847 // Personality Encoding
848 EmitEncodingByte(streamer, personalityEncoding,
849 "Personality Encoding");
851 if (verboseAsm) streamer.AddComment("Personality");
852 EmitPersonality(streamer, *personality, personalityEncoding);
856 EmitEncodingByte(streamer, lsdaEncoding, "LSDA Encoding");
858 // Encoding of the FDE pointers
859 EmitEncodingByte(streamer, MOFI->getFDEEncoding(UsingCFI),
863 // Initial Instructions
865 const MCAsmInfo &MAI = context.getAsmInfo();
866 const std::vector<MachineMove> &Moves = MAI.getInitialFrameState();
867 std::vector<MCCFIInstruction> Instructions;
869 for (int i = 0, n = Moves.size(); i != n; ++i) {
870 MCSymbol *Label = Moves[i].getLabel();
871 const MachineLocation &Dst =
872 TranslateMachineLocation(MRI, Moves[i].getDestination());
873 const MachineLocation &Src =
874 TranslateMachineLocation(MRI, Moves[i].getSource());
875 MCCFIInstruction Inst(Label, Dst, Src);
876 Instructions.push_back(Inst);
879 EmitCFIInstructions(streamer, Instructions, NULL);
882 streamer.EmitValueToAlignment(IsEH
883 ? 4 : context.getAsmInfo().getPointerSize());
885 streamer.EmitLabel(sectionEnd);
886 return *sectionStart;
889 MCSymbol *FrameEmitterImpl::EmitFDE(MCStreamer &streamer,
890 const MCSymbol &cieStart,
891 const MCDwarfFrameInfo &frame) {
892 MCContext &context = streamer.getContext();
893 MCSymbol *fdeStart = context.CreateTempSymbol();
894 MCSymbol *fdeEnd = context.CreateTempSymbol();
895 const MCObjectFileInfo *MOFI = context.getObjectFileInfo();
896 bool verboseAsm = streamer.isVerboseAsm();
898 if (IsEH && frame.Function && !MOFI->isFunctionEHFrameSymbolPrivate()) {
900 context.GetOrCreateSymbol(frame.Function->getName() + Twine(".eh"));
901 streamer.EmitEHSymAttributes(frame.Function, EHSym);
902 streamer.EmitLabel(EHSym);
906 const MCExpr *Length = MakeStartMinusEndExpr(streamer, *fdeStart, *fdeEnd, 0);
907 if (verboseAsm) streamer.AddComment("FDE Length");
908 streamer.EmitAbsValue(Length, 4);
910 streamer.EmitLabel(fdeStart);
913 const MCAsmInfo &asmInfo = context.getAsmInfo();
915 const MCExpr *offset = MakeStartMinusEndExpr(streamer, cieStart, *fdeStart,
917 if (verboseAsm) streamer.AddComment("FDE CIE Offset");
918 streamer.EmitAbsValue(offset, 4);
919 } else if (!asmInfo.doesDwarfRequireRelocationForSectionOffset()) {
920 const MCExpr *offset = MakeStartMinusEndExpr(streamer, *SectionStart,
922 streamer.EmitAbsValue(offset, 4);
924 streamer.EmitSymbolValue(&cieStart, 4);
927 unsigned fdeEncoding = MOFI->getFDEEncoding(UsingCFI);
928 unsigned size = getSizeForEncoding(streamer, fdeEncoding);
931 unsigned PCBeginEncoding = IsEH ? fdeEncoding :
932 (unsigned)dwarf::DW_EH_PE_absptr;
933 unsigned PCBeginSize = getSizeForEncoding(streamer, PCBeginEncoding);
934 EmitSymbol(streamer, *frame.Begin, PCBeginEncoding, "FDE initial location");
937 const MCExpr *Range = MakeStartMinusEndExpr(streamer, *frame.Begin,
939 if (verboseAsm) streamer.AddComment("FDE address range");
940 streamer.EmitAbsValue(Range, size);
943 // Augmentation Data Length
944 unsigned augmentationLength = 0;
947 augmentationLength += getSizeForEncoding(streamer, frame.LsdaEncoding);
949 if (verboseAsm) streamer.AddComment("Augmentation size");
950 streamer.EmitULEB128IntValue(augmentationLength);
954 EmitSymbol(streamer, *frame.Lsda, frame.LsdaEncoding,
955 "Language Specific Data Area");
958 // Call Frame Instructions
960 EmitCFIInstructions(streamer, frame.Instructions, frame.Begin);
963 streamer.EmitValueToAlignment(PCBeginSize);
970 static const CIEKey getEmptyKey() { return CIEKey(0, 0, -1); }
971 static const CIEKey getTombstoneKey() { return CIEKey(0, -1, 0); }
973 CIEKey(const MCSymbol* Personality_, unsigned PersonalityEncoding_,
974 unsigned LsdaEncoding_) : Personality(Personality_),
975 PersonalityEncoding(PersonalityEncoding_),
976 LsdaEncoding(LsdaEncoding_) {
978 const MCSymbol* Personality;
979 unsigned PersonalityEncoding;
980 unsigned LsdaEncoding;
986 struct DenseMapInfo<CIEKey> {
987 static CIEKey getEmptyKey() {
988 return CIEKey::getEmptyKey();
990 static CIEKey getTombstoneKey() {
991 return CIEKey::getTombstoneKey();
993 static unsigned getHashValue(const CIEKey &Key) {
995 ID.AddPointer(Key.Personality);
996 ID.AddInteger(Key.PersonalityEncoding);
997 ID.AddInteger(Key.LsdaEncoding);
998 return ID.ComputeHash();
1000 static bool isEqual(const CIEKey &LHS,
1001 const CIEKey &RHS) {
1002 return LHS.Personality == RHS.Personality &&
1003 LHS.PersonalityEncoding == RHS.PersonalityEncoding &&
1004 LHS.LsdaEncoding == RHS.LsdaEncoding;
1009 void MCDwarfFrameEmitter::Emit(MCStreamer &Streamer,
1012 MCContext &Context = Streamer.getContext();
1013 MCObjectFileInfo *MOFI =
1014 const_cast<MCObjectFileInfo*>(Context.getObjectFileInfo());
1015 FrameEmitterImpl Emitter(UsingCFI, IsEH);
1016 ArrayRef<MCDwarfFrameInfo> FrameArray = Streamer.getFrameInfos();
1018 // Emit the compact unwind info if available.
1019 // FIXME: This emits both the compact unwind and the old CIE/FDE
1020 // information. Only one of those is needed.
1021 if (IsEH && MOFI->getCompactUnwindSection())
1022 for (unsigned i = 0, n = Streamer.getNumFrameInfos(); i < n; ++i) {
1023 const MCDwarfFrameInfo &Frame = Streamer.getFrameInfo(i);
1024 if (!Frame.CompactUnwindEncoding)
1025 Emitter.EmitCompactUnwind(Streamer, Frame);
1028 const MCSection &Section = IsEH ? *MOFI->getEHFrameSection() :
1029 *MOFI->getDwarfFrameSection();
1030 Streamer.SwitchSection(&Section);
1031 MCSymbol *SectionStart = Context.CreateTempSymbol();
1032 Streamer.EmitLabel(SectionStart);
1033 Emitter.setSectionStart(SectionStart);
1035 MCSymbol *FDEEnd = NULL;
1036 DenseMap<CIEKey, const MCSymbol*> CIEStarts;
1038 const MCSymbol *DummyDebugKey = NULL;
1039 for (unsigned i = 0, n = FrameArray.size(); i < n; ++i) {
1040 const MCDwarfFrameInfo &Frame = FrameArray[i];
1041 CIEKey Key(Frame.Personality, Frame.PersonalityEncoding,
1042 Frame.LsdaEncoding);
1043 const MCSymbol *&CIEStart = IsEH ? CIEStarts[Key] : DummyDebugKey;
1045 CIEStart = &Emitter.EmitCIE(Streamer, Frame.Personality,
1046 Frame.PersonalityEncoding, Frame.Lsda,
1047 Frame.LsdaEncoding);
1049 FDEEnd = Emitter.EmitFDE(Streamer, *CIEStart, Frame);
1052 Streamer.EmitLabel(FDEEnd);
1055 Streamer.EmitValueToAlignment(Context.getAsmInfo().getPointerSize());
1057 Streamer.EmitLabel(FDEEnd);
1060 void MCDwarfFrameEmitter::EmitAdvanceLoc(MCStreamer &Streamer,
1061 uint64_t AddrDelta) {
1062 SmallString<256> Tmp;
1063 raw_svector_ostream OS(Tmp);
1064 MCDwarfFrameEmitter::EncodeAdvanceLoc(AddrDelta, OS);
1065 Streamer.EmitBytes(OS.str(), /*AddrSpace=*/0);
1068 void MCDwarfFrameEmitter::EncodeAdvanceLoc(uint64_t AddrDelta,
1070 // FIXME: Assumes the code alignment factor is 1.
1071 if (AddrDelta == 0) {
1072 } else if (isUIntN(6, AddrDelta)) {
1073 uint8_t Opcode = dwarf::DW_CFA_advance_loc | AddrDelta;
1075 } else if (isUInt<8>(AddrDelta)) {
1076 OS << uint8_t(dwarf::DW_CFA_advance_loc1);
1077 OS << uint8_t(AddrDelta);
1078 } else if (isUInt<16>(AddrDelta)) {
1079 // FIXME: check what is the correct behavior on a big endian machine.
1080 OS << uint8_t(dwarf::DW_CFA_advance_loc2);
1081 OS << uint8_t( AddrDelta & 0xff);
1082 OS << uint8_t((AddrDelta >> 8) & 0xff);
1084 // FIXME: check what is the correct behavior on a big endian machine.
1085 assert(isUInt<32>(AddrDelta));
1086 OS << uint8_t(dwarf::DW_CFA_advance_loc4);
1087 OS << uint8_t( AddrDelta & 0xff);
1088 OS << uint8_t((AddrDelta >> 8) & 0xff);
1089 OS << uint8_t((AddrDelta >> 16) & 0xff);
1090 OS << uint8_t((AddrDelta >> 24) & 0xff);