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/MCAsmInfo.h"
11 #include "llvm/MC/MCDwarf.h"
12 #include "llvm/MC/MCStreamer.h"
13 #include "llvm/MC/MCSymbol.h"
14 #include "llvm/MC/MCExpr.h"
15 #include "llvm/MC/MCContext.h"
16 #include "llvm/MC/MCObjectWriter.h"
17 #include "llvm/Support/Debug.h"
18 #include "llvm/Support/ErrorHandling.h"
19 #include "llvm/Support/raw_ostream.h"
20 #include "llvm/Target/TargetAsmInfo.h"
21 #include "llvm/ADT/FoldingSet.h"
22 #include "llvm/ADT/SmallString.h"
23 #include "llvm/ADT/StringExtras.h"
24 #include "llvm/ADT/Twine.h"
27 // Given a special op, return the address skip amount (in units of
28 // DWARF2_LINE_MIN_INSN_LENGTH.
29 #define SPECIAL_ADDR(op) (((op) - DWARF2_LINE_OPCODE_BASE)/DWARF2_LINE_RANGE)
31 // The maximum address skip amount that can be encoded with a special op.
32 #define MAX_SPECIAL_ADDR_DELTA SPECIAL_ADDR(255)
34 // First special line opcode - leave room for the standard opcodes.
35 // Note: If you want to change this, you'll have to update the
36 // "standard_opcode_lengths" table that is emitted in DwarfFileTable::Emit().
37 #define DWARF2_LINE_OPCODE_BASE 13
39 // Minimum line offset in a special line info. opcode. This value
40 // was chosen to give a reasonable range of values.
41 #define DWARF2_LINE_BASE -5
43 // Range of line offsets in a special line info. opcode.
44 #define DWARF2_LINE_RANGE 14
46 // Define the architecture-dependent minimum instruction length (in bytes).
47 // This value should be rather too small than too big.
48 #define DWARF2_LINE_MIN_INSN_LENGTH 1
50 // Note: when DWARF2_LINE_MIN_INSN_LENGTH == 1 which is the current setting,
51 // this routine is a nop and will be optimized away.
52 static inline uint64_t ScaleAddrDelta(uint64_t AddrDelta) {
53 if (DWARF2_LINE_MIN_INSN_LENGTH == 1)
55 if (AddrDelta % DWARF2_LINE_MIN_INSN_LENGTH != 0) {
56 // TODO: report this error, but really only once.
59 return AddrDelta / DWARF2_LINE_MIN_INSN_LENGTH;
63 // This is called when an instruction is assembled into the specified section
64 // and if there is information from the last .loc directive that has yet to have
65 // a line entry made for it is made.
67 void MCLineEntry::Make(MCStreamer *MCOS, const MCSection *Section) {
68 if (!MCOS->getContext().getDwarfLocSeen())
71 // Create a symbol at in the current section for use in the line entry.
72 MCSymbol *LineSym = MCOS->getContext().CreateTempSymbol();
73 // Set the value of the symbol to use for the MCLineEntry.
74 MCOS->EmitLabel(LineSym);
76 // Get the current .loc info saved in the context.
77 const MCDwarfLoc &DwarfLoc = MCOS->getContext().getCurrentDwarfLoc();
79 // Create a (local) line entry with the symbol and the current .loc info.
80 MCLineEntry LineEntry(LineSym, DwarfLoc);
82 // clear DwarfLocSeen saying the current .loc info is now used.
83 MCOS->getContext().ClearDwarfLocSeen();
85 // Get the MCLineSection for this section, if one does not exist for this
87 const DenseMap<const MCSection *, MCLineSection *> &MCLineSections =
88 MCOS->getContext().getMCLineSections();
89 MCLineSection *LineSection = MCLineSections.lookup(Section);
91 // Create a new MCLineSection. This will be deleted after the dwarf line
92 // table is created using it by iterating through the MCLineSections
94 LineSection = new MCLineSection;
95 // Save a pointer to the new LineSection into the MCLineSections DenseMap.
96 MCOS->getContext().addMCLineSection(Section, LineSection);
99 // Add the line entry to this section's entries.
100 LineSection->addLineEntry(LineEntry);
104 // This helper routine returns an expression of End - Start + IntVal .
106 static inline const MCExpr *MakeStartMinusEndExpr(const MCStreamer &MCOS,
107 const MCSymbol &Start,
110 MCSymbolRefExpr::VariantKind Variant = MCSymbolRefExpr::VK_None;
112 MCSymbolRefExpr::Create(&End, Variant, MCOS.getContext());
114 MCSymbolRefExpr::Create(&Start, Variant, MCOS.getContext());
116 MCBinaryExpr::Create(MCBinaryExpr::Sub, Res, RHS, MCOS.getContext());
118 MCConstantExpr::Create(IntVal, MCOS.getContext());
120 MCBinaryExpr::Create(MCBinaryExpr::Sub, Res1, Res2, MCOS.getContext());
125 // This emits the Dwarf line table for the specified section from the entries
126 // in the LineSection.
128 static inline void EmitDwarfLineTable(MCStreamer *MCOS,
129 const MCSection *Section,
130 const MCLineSection *LineSection) {
131 unsigned FileNum = 1;
132 unsigned LastLine = 1;
134 unsigned Flags = DWARF2_LINE_DEFAULT_IS_STMT ? DWARF2_FLAG_IS_STMT : 0;
136 MCSymbol *LastLabel = NULL;
138 // Loop through each MCLineEntry and encode the dwarf line number table.
139 for (MCLineSection::const_iterator
140 it = LineSection->getMCLineEntries()->begin(),
141 ie = LineSection->getMCLineEntries()->end(); it != ie; ++it) {
143 if (FileNum != it->getFileNum()) {
144 FileNum = it->getFileNum();
145 MCOS->EmitIntValue(dwarf::DW_LNS_set_file, 1);
146 MCOS->EmitULEB128IntValue(FileNum);
148 if (Column != it->getColumn()) {
149 Column = it->getColumn();
150 MCOS->EmitIntValue(dwarf::DW_LNS_set_column, 1);
151 MCOS->EmitULEB128IntValue(Column);
153 if (Isa != it->getIsa()) {
155 MCOS->EmitIntValue(dwarf::DW_LNS_set_isa, 1);
156 MCOS->EmitULEB128IntValue(Isa);
158 if ((it->getFlags() ^ Flags) & DWARF2_FLAG_IS_STMT) {
159 Flags = it->getFlags();
160 MCOS->EmitIntValue(dwarf::DW_LNS_negate_stmt, 1);
162 if (it->getFlags() & DWARF2_FLAG_BASIC_BLOCK)
163 MCOS->EmitIntValue(dwarf::DW_LNS_set_basic_block, 1);
164 if (it->getFlags() & DWARF2_FLAG_PROLOGUE_END)
165 MCOS->EmitIntValue(dwarf::DW_LNS_set_prologue_end, 1);
166 if (it->getFlags() & DWARF2_FLAG_EPILOGUE_BEGIN)
167 MCOS->EmitIntValue(dwarf::DW_LNS_set_epilogue_begin, 1);
169 int64_t LineDelta = static_cast<int64_t>(it->getLine()) - LastLine;
170 MCSymbol *Label = it->getLabel();
172 // At this point we want to emit/create the sequence to encode the delta in
173 // line numbers and the increment of the address from the previous Label
174 // and the current Label.
175 const TargetAsmInfo &asmInfo = MCOS->getContext().getTargetAsmInfo();
176 MCOS->EmitDwarfAdvanceLineAddr(LineDelta, LastLabel, Label,
177 asmInfo.getPointerSize());
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 const TargetAsmInfo &asmInfo = MCOS->getContext().getTargetAsmInfo();
202 MCOS->EmitDwarfAdvanceLineAddr(INT64_MAX, LastLabel, SectionEnd,
203 asmInfo.getPointerSize());
207 // This emits the Dwarf file and the line tables.
209 void MCDwarfFileTable::Emit(MCStreamer *MCOS) {
210 MCContext &context = MCOS->getContext();
211 // Switch to the section where the table will be emitted into.
212 MCOS->SwitchSection(context.getTargetAsmInfo().getDwarfLineSection());
214 // Create a symbol at the beginning of this section.
215 MCSymbol *LineStartSym = context.CreateTempSymbol();
216 // Set the value of the symbol, as we are at the start of the section.
217 MCOS->EmitLabel(LineStartSym);
219 // Create a symbol for the end of the section (to be set when we get there).
220 MCSymbol *LineEndSym = context.CreateTempSymbol();
222 // The first 4 bytes is the total length of the information for this
223 // compilation unit (not including these 4 bytes for the length).
224 MCOS->EmitAbsValue(MakeStartMinusEndExpr(*MCOS, *LineStartSym, *LineEndSym,4),
227 // Next 2 bytes is the Version, which is Dwarf 2.
228 MCOS->EmitIntValue(2, 2);
230 // Create a symbol for the end of the prologue (to be set when we get there).
231 MCSymbol *ProEndSym = context.CreateTempSymbol(); // Lprologue_end
233 // Length of the prologue, is the next 4 bytes. Which is the start of the
234 // section to the end of the prologue. Not including the 4 bytes for the
235 // total length, the 2 bytes for the version, and these 4 bytes for the
236 // length of the prologue.
237 MCOS->EmitAbsValue(MakeStartMinusEndExpr(*MCOS, *LineStartSym, *ProEndSym,
241 // Parameters of the state machine, are next.
242 MCOS->EmitIntValue(DWARF2_LINE_MIN_INSN_LENGTH, 1);
243 MCOS->EmitIntValue(DWARF2_LINE_DEFAULT_IS_STMT, 1);
244 MCOS->EmitIntValue(DWARF2_LINE_BASE, 1);
245 MCOS->EmitIntValue(DWARF2_LINE_RANGE, 1);
246 MCOS->EmitIntValue(DWARF2_LINE_OPCODE_BASE, 1);
248 // Standard opcode lengths
249 MCOS->EmitIntValue(0, 1); // length of DW_LNS_copy
250 MCOS->EmitIntValue(1, 1); // length of DW_LNS_advance_pc
251 MCOS->EmitIntValue(1, 1); // length of DW_LNS_advance_line
252 MCOS->EmitIntValue(1, 1); // length of DW_LNS_set_file
253 MCOS->EmitIntValue(1, 1); // length of DW_LNS_set_column
254 MCOS->EmitIntValue(0, 1); // length of DW_LNS_negate_stmt
255 MCOS->EmitIntValue(0, 1); // length of DW_LNS_set_basic_block
256 MCOS->EmitIntValue(0, 1); // length of DW_LNS_const_add_pc
257 MCOS->EmitIntValue(1, 1); // length of DW_LNS_fixed_advance_pc
258 MCOS->EmitIntValue(0, 1); // length of DW_LNS_set_prologue_end
259 MCOS->EmitIntValue(0, 1); // length of DW_LNS_set_epilogue_begin
260 MCOS->EmitIntValue(1, 1); // DW_LNS_set_isa
262 // Put out the directory and file tables.
264 // First the directory table.
265 const std::vector<StringRef> &MCDwarfDirs =
266 context.getMCDwarfDirs();
267 for (unsigned i = 0; i < MCDwarfDirs.size(); i++) {
268 MCOS->EmitBytes(MCDwarfDirs[i], 0); // the DirectoryName
269 MCOS->EmitBytes(StringRef("\0", 1), 0); // the null term. of the string
271 MCOS->EmitIntValue(0, 1); // Terminate the directory list
273 // Second the file table.
274 const std::vector<MCDwarfFile *> &MCDwarfFiles =
275 MCOS->getContext().getMCDwarfFiles();
276 for (unsigned i = 1; i < MCDwarfFiles.size(); i++) {
277 MCOS->EmitBytes(MCDwarfFiles[i]->getName(), 0); // FileName
278 MCOS->EmitBytes(StringRef("\0", 1), 0); // the null term. of the string
280 MCOS->EmitULEB128IntValue(MCDwarfFiles[i]->getDirIndex());
281 MCOS->EmitIntValue(0, 1); // last modification timestamp (always 0)
282 MCOS->EmitIntValue(0, 1); // filesize (always 0)
284 MCOS->EmitIntValue(0, 1); // Terminate the file list
286 // This is the end of the prologue, so set the value of the symbol at the
287 // end of the prologue (that was used in a previous expression).
288 MCOS->EmitLabel(ProEndSym);
290 // Put out the line tables.
291 const DenseMap<const MCSection *, MCLineSection *> &MCLineSections =
292 MCOS->getContext().getMCLineSections();
293 const std::vector<const MCSection *> &MCLineSectionOrder =
294 MCOS->getContext().getMCLineSectionOrder();
295 for (std::vector<const MCSection*>::const_iterator it =
296 MCLineSectionOrder.begin(), ie = MCLineSectionOrder.end(); it != ie;
298 const MCSection *Sec = *it;
299 const MCLineSection *Line = MCLineSections.lookup(Sec);
300 EmitDwarfLineTable(MCOS, Sec, Line);
302 // Now delete the MCLineSections that were created in MCLineEntry::Make()
303 // and used to emit the line table.
307 if (MCOS->getContext().getAsmInfo().getLinkerRequiresNonEmptyDwarfLines()
308 && MCLineSectionOrder.begin() == MCLineSectionOrder.end()) {
309 // The darwin9 linker has a bug (see PR8715). For for 32-bit architectures
311 // total_length >= prologue_length + 10
312 // We are 4 bytes short, since we have total_length = 51 and
313 // prologue_length = 45
315 // The regular end_sequence should be sufficient.
316 MCDwarfLineAddr::Emit(MCOS, INT64_MAX, 0);
319 // This is the end of the section, so set the value of the symbol at the end
320 // of this section (that was used in a previous expression).
321 MCOS->EmitLabel(LineEndSym);
324 /// Utility function to write the encoding to an object writer.
325 void MCDwarfLineAddr::Write(MCObjectWriter *OW, int64_t LineDelta,
326 uint64_t AddrDelta) {
327 SmallString<256> Tmp;
328 raw_svector_ostream OS(Tmp);
329 MCDwarfLineAddr::Encode(LineDelta, AddrDelta, OS);
330 OW->WriteBytes(OS.str());
333 /// Utility function to emit the encoding to a streamer.
334 void MCDwarfLineAddr::Emit(MCStreamer *MCOS, int64_t LineDelta,
335 uint64_t AddrDelta) {
336 SmallString<256> Tmp;
337 raw_svector_ostream OS(Tmp);
338 MCDwarfLineAddr::Encode(LineDelta, AddrDelta, OS);
339 MCOS->EmitBytes(OS.str(), /*AddrSpace=*/0);
342 /// Utility function to encode a Dwarf pair of LineDelta and AddrDeltas.
343 void MCDwarfLineAddr::Encode(int64_t LineDelta, uint64_t AddrDelta,
345 uint64_t Temp, Opcode;
346 bool NeedCopy = false;
348 // Scale the address delta by the minimum instruction length.
349 AddrDelta = ScaleAddrDelta(AddrDelta);
351 // A LineDelta of INT64_MAX is a signal that this is actually a
352 // DW_LNE_end_sequence. We cannot use special opcodes here, since we want the
353 // end_sequence to emit the matrix entry.
354 if (LineDelta == INT64_MAX) {
355 if (AddrDelta == MAX_SPECIAL_ADDR_DELTA)
356 OS << char(dwarf::DW_LNS_const_add_pc);
358 OS << char(dwarf::DW_LNS_advance_pc);
359 MCObjectWriter::EncodeULEB128(AddrDelta, OS);
361 OS << char(dwarf::DW_LNS_extended_op);
363 OS << char(dwarf::DW_LNE_end_sequence);
367 // Bias the line delta by the base.
368 Temp = LineDelta - DWARF2_LINE_BASE;
370 // If the line increment is out of range of a special opcode, we must encode
371 // it with DW_LNS_advance_line.
372 if (Temp >= DWARF2_LINE_RANGE) {
373 OS << char(dwarf::DW_LNS_advance_line);
375 raw_svector_ostream OSE(Tmp);
376 MCObjectWriter::EncodeSLEB128(LineDelta, OSE);
380 Temp = 0 - DWARF2_LINE_BASE;
384 // Use DW_LNS_copy instead of a "line +0, addr +0" special opcode.
385 if (LineDelta == 0 && AddrDelta == 0) {
386 OS << char(dwarf::DW_LNS_copy);
390 // Bias the opcode by the special opcode base.
391 Temp += DWARF2_LINE_OPCODE_BASE;
393 // Avoid overflow when addr_delta is large.
394 if (AddrDelta < 256 + MAX_SPECIAL_ADDR_DELTA) {
395 // Try using a special opcode.
396 Opcode = Temp + AddrDelta * DWARF2_LINE_RANGE;
402 // Try using DW_LNS_const_add_pc followed by special op.
403 Opcode = Temp + (AddrDelta - MAX_SPECIAL_ADDR_DELTA) * DWARF2_LINE_RANGE;
405 OS << char(dwarf::DW_LNS_const_add_pc);
411 // Otherwise use DW_LNS_advance_pc.
412 OS << char(dwarf::DW_LNS_advance_pc);
414 raw_svector_ostream OSE(Tmp);
415 MCObjectWriter::EncodeULEB128(AddrDelta, OSE);
419 OS << char(dwarf::DW_LNS_copy);
424 void MCDwarfFile::print(raw_ostream &OS) const {
425 OS << '"' << getName() << '"';
428 void MCDwarfFile::dump() const {
432 static int getDataAlignmentFactor(MCStreamer &streamer) {
433 MCContext &context = streamer.getContext();
434 const TargetAsmInfo &asmInfo = context.getTargetAsmInfo();
435 int size = asmInfo.getPointerSize();
436 if (asmInfo.getStackGrowthDirection() == TargetFrameLowering::StackGrowsUp)
442 static unsigned getSizeForEncoding(MCStreamer &streamer,
443 unsigned symbolEncoding) {
444 MCContext &context = streamer.getContext();
445 const TargetAsmInfo &asmInfo = context.getTargetAsmInfo();
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 asmInfo.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 TargetAsmInfo &AsmInfo,
490 const MachineLocation &Loc) {
491 unsigned Reg = Loc.getReg() == MachineLocation::VirtualFP ?
492 MachineLocation::VirtualFP :
493 unsigned(AsmInfo.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, const MCSymbol *sectionStart) :
508 CFAOffset(0), CIENum(0), UsingCFI(usingCFI), IsEH(isEH),
509 SectionStart(sectionStart) {
512 /// EmitCompactUnwind - Emit the unwind information in a compact way. If
513 /// we're successful, return 'true'. Otherwise, return 'false' and it will
514 /// emit the normal CIE and FDE.
515 bool EmitCompactUnwind(MCStreamer &streamer,
516 const MCDwarfFrameInfo &frame);
518 const MCSymbol &EmitCIE(MCStreamer &streamer,
519 const MCSymbol *personality,
520 unsigned personalityEncoding,
521 const MCSymbol *lsda,
522 unsigned lsdaEncoding);
523 MCSymbol *EmitFDE(MCStreamer &streamer,
524 const MCSymbol &cieStart,
525 const MCDwarfFrameInfo &frame);
526 void EmitCFIInstructions(MCStreamer &streamer,
527 const std::vector<MCCFIInstruction> &Instrs,
528 MCSymbol *BaseLabel);
529 void EmitCFIInstruction(MCStreamer &Streamer,
530 const MCCFIInstruction &Instr);
533 } // end anonymous namespace
535 static void EmitEncodingByte(MCStreamer &Streamer, unsigned Encoding,
537 if (Streamer.isVerboseAsm()) {
538 const char *EncStr = 0;
540 default: EncStr = "<unknown encoding>";
541 case dwarf::DW_EH_PE_absptr: EncStr = "absptr";
542 case dwarf::DW_EH_PE_omit: EncStr = "omit";
543 case dwarf::DW_EH_PE_pcrel: EncStr = "pcrel";
544 case dwarf::DW_EH_PE_udata4: EncStr = "udata4";
545 case dwarf::DW_EH_PE_udata8: EncStr = "udata8";
546 case dwarf::DW_EH_PE_sdata4: EncStr = "sdata4";
547 case dwarf::DW_EH_PE_sdata8: EncStr = "sdata8";
548 case dwarf::DW_EH_PE_pcrel |dwarf::DW_EH_PE_udata4: EncStr = "pcrel udata4";
549 case dwarf::DW_EH_PE_pcrel |dwarf::DW_EH_PE_sdata4: EncStr = "pcrel sdata4";
550 case dwarf::DW_EH_PE_pcrel |dwarf::DW_EH_PE_udata8: EncStr = "pcrel udata8";
551 case dwarf::DW_EH_PE_pcrel |dwarf::DW_EH_PE_sdata8: EncStr = "pcrel sdata8";
552 case dwarf::DW_EH_PE_indirect |dwarf::DW_EH_PE_pcrel|dwarf::DW_EH_PE_udata4:
553 EncStr = "indirect pcrel udata4";
554 case dwarf::DW_EH_PE_indirect |dwarf::DW_EH_PE_pcrel|dwarf::DW_EH_PE_sdata4:
555 EncStr = "indirect pcrel sdata4";
556 case dwarf::DW_EH_PE_indirect |dwarf::DW_EH_PE_pcrel|dwarf::DW_EH_PE_udata8:
557 EncStr = "indirect pcrel udata8";
558 case dwarf::DW_EH_PE_indirect |dwarf::DW_EH_PE_pcrel|dwarf::DW_EH_PE_sdata8:
559 EncStr = "indirect pcrel sdata8";
562 Streamer.AddComment(Twine(Prefix) + " = " + EncStr);
565 Streamer.EmitIntValue(Encoding, 1);
568 void FrameEmitterImpl::EmitCFIInstruction(MCStreamer &Streamer,
569 const MCCFIInstruction &Instr) {
570 int dataAlignmentFactor = getDataAlignmentFactor(Streamer);
571 bool VerboseAsm = Streamer.isVerboseAsm();
573 switch (Instr.getOperation()) {
574 case MCCFIInstruction::Move:
575 case MCCFIInstruction::RelMove: {
576 const MachineLocation &Dst = Instr.getDestination();
577 const MachineLocation &Src = Instr.getSource();
578 const bool IsRelative = Instr.getOperation() == MCCFIInstruction::RelMove;
581 if (Dst.isReg() && Dst.getReg() == MachineLocation::VirtualFP) {
582 if (Src.getReg() == MachineLocation::VirtualFP) {
583 if (VerboseAsm) Streamer.AddComment("DW_CFA_def_cfa_offset");
584 Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa_offset, 1);
586 if (VerboseAsm) Streamer.AddComment("DW_CFA_def_cfa");
587 Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa, 1);
588 if (VerboseAsm) Streamer.AddComment(Twine("Reg ") +
589 Twine(Src.getReg()));
590 Streamer.EmitULEB128IntValue(Src.getReg());
594 CFAOffset += Src.getOffset();
596 CFAOffset = -Src.getOffset();
598 if (VerboseAsm) Streamer.AddComment(Twine("Offset " + Twine(CFAOffset)));
599 Streamer.EmitULEB128IntValue(CFAOffset);
603 if (Src.isReg() && Src.getReg() == MachineLocation::VirtualFP) {
604 assert(Dst.isReg() && "Machine move not supported yet.");
605 if (VerboseAsm) Streamer.AddComment("DW_CFA_def_cfa_register");
606 Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa_register, 1);
607 if (VerboseAsm) Streamer.AddComment(Twine("Reg ") + Twine(Dst.getReg()));
608 Streamer.EmitULEB128IntValue(Dst.getReg());
612 unsigned Reg = Src.getReg();
613 int Offset = Dst.getOffset();
616 Offset = Offset / dataAlignmentFactor;
619 if (VerboseAsm) Streamer.AddComment("DW_CFA_offset_extended_sf");
620 Streamer.EmitIntValue(dwarf::DW_CFA_offset_extended_sf, 1);
621 if (VerboseAsm) Streamer.AddComment(Twine("Reg ") + Twine(Reg));
622 Streamer.EmitULEB128IntValue(Reg);
623 if (VerboseAsm) Streamer.AddComment(Twine("Offset ") + Twine(Offset));
624 Streamer.EmitSLEB128IntValue(Offset);
625 } else if (Reg < 64) {
626 if (VerboseAsm) Streamer.AddComment(Twine("DW_CFA_offset + Reg(") +
628 Streamer.EmitIntValue(dwarf::DW_CFA_offset + Reg, 1);
629 if (VerboseAsm) Streamer.AddComment(Twine("Offset ") + Twine(Offset));
630 Streamer.EmitULEB128IntValue(Offset);
632 if (VerboseAsm) Streamer.AddComment("DW_CFA_offset_extended");
633 Streamer.EmitIntValue(dwarf::DW_CFA_offset_extended, 1);
634 if (VerboseAsm) Streamer.AddComment(Twine("Reg ") + Twine(Reg));
635 Streamer.EmitULEB128IntValue(Reg);
636 if (VerboseAsm) Streamer.AddComment(Twine("Offset ") + Twine(Offset));
637 Streamer.EmitULEB128IntValue(Offset);
641 case MCCFIInstruction::Remember:
642 if (VerboseAsm) Streamer.AddComment("DW_CFA_remember_state");
643 Streamer.EmitIntValue(dwarf::DW_CFA_remember_state, 1);
645 case MCCFIInstruction::Restore:
646 if (VerboseAsm) Streamer.AddComment("DW_CFA_restore_state");
647 Streamer.EmitIntValue(dwarf::DW_CFA_restore_state, 1);
649 case MCCFIInstruction::SameValue: {
650 unsigned Reg = Instr.getDestination().getReg();
651 if (VerboseAsm) Streamer.AddComment("DW_CFA_same_value");
652 Streamer.EmitIntValue(dwarf::DW_CFA_same_value, 1);
653 if (VerboseAsm) Streamer.AddComment(Twine("Reg ") + Twine(Reg));
654 Streamer.EmitULEB128IntValue(Reg);
658 llvm_unreachable("Unhandled case in switch");
661 /// EmitFrameMoves - Emit frame instructions to describe the layout of the
663 void FrameEmitterImpl::EmitCFIInstructions(MCStreamer &streamer,
664 const std::vector<MCCFIInstruction> &Instrs,
665 MCSymbol *BaseLabel) {
666 for (unsigned i = 0, N = Instrs.size(); i < N; ++i) {
667 const MCCFIInstruction &Instr = Instrs[i];
668 MCSymbol *Label = Instr.getLabel();
669 // Throw out move if the label is invalid.
670 if (Label && !Label->isDefined()) continue; // Not emitted, in dead code.
672 // Advance row if new location.
673 if (BaseLabel && Label) {
674 MCSymbol *ThisSym = Label;
675 if (ThisSym != BaseLabel) {
676 if (streamer.isVerboseAsm()) streamer.AddComment("DW_CFA_advance_loc4");
677 streamer.EmitDwarfAdvanceFrameAddr(BaseLabel, ThisSym);
682 EmitCFIInstruction(streamer, Instr);
686 /// EmitCompactUnwind - Emit the unwind information in a compact way. If we're
687 /// successful, return 'true'. Otherwise, return 'false' and it will emit the
688 /// normal CIE and FDE.
689 bool FrameEmitterImpl::EmitCompactUnwind(MCStreamer &Streamer,
690 const MCDwarfFrameInfo &Frame) {
694 MCContext &Context = Streamer.getContext();
695 const TargetAsmInfo &TAI = Context.getTargetAsmInfo();
696 bool VerboseAsm = Streamer.isVerboseAsm();
698 // range-start range-length compact-unwind-enc personality-func lsda
699 // _foo LfooEnd-_foo 0x00000023 0 0
700 // _bar LbarEnd-_bar 0x00000025 __gxx_personality except_tab1
702 // .section __LD,__compact_unwind,regular,debug
704 // # compact unwind for _foo
706 // .set L1,LfooEnd-_foo
712 // # compact unwind for _bar
714 // .set L2,LbarEnd-_bar
717 // .quad __gxx_personality
721 TAI.getCompactUnwindEncoding(Frame.Instructions,
722 getDataAlignmentFactor(Streamer), IsEH);
723 if (!Encoding) return false;
725 // The encoding needs to know we have an LSDA.
727 Encoding |= 0x40000000;
729 Streamer.SwitchSection(TAI.getCompactUnwindSection());
732 unsigned FDEEncoding = TAI.getFDEEncoding(UsingCFI);
733 unsigned Size = getSizeForEncoding(Streamer, FDEEncoding);
734 if (VerboseAsm) Streamer.AddComment("Range Start");
735 Streamer.EmitSymbolValue(Frame.Function, Size);
738 const MCExpr *Range = MakeStartMinusEndExpr(Streamer, *Frame.Begin,
740 if (VerboseAsm) Streamer.AddComment("Range Length");
741 Streamer.EmitAbsValue(Range, 4);
744 Size = getSizeForEncoding(Streamer, dwarf::DW_EH_PE_udata4);
745 if (VerboseAsm) Streamer.AddComment(Twine("Compact Unwind Encoding: 0x") +
746 Twine(llvm::utohexstr(Encoding)));
747 Streamer.EmitIntValue(Encoding, Size);
749 // Personality Function
750 Size = getSizeForEncoding(Streamer, dwarf::DW_EH_PE_absptr);
751 if (VerboseAsm) Streamer.AddComment("Personality Function");
752 if (Frame.Personality)
753 Streamer.EmitSymbolValue(Frame.Personality, Size);
755 Streamer.EmitIntValue(0, Size); // No personality fn
758 Size = getSizeForEncoding(Streamer, Frame.LsdaEncoding);
759 if (VerboseAsm) Streamer.AddComment("LSDA");
761 Streamer.EmitSymbolValue(Frame.Lsda, Size);
763 Streamer.EmitIntValue(0, Size); // No LSDA
769 const MCSymbol &FrameEmitterImpl::EmitCIE(MCStreamer &streamer,
770 const MCSymbol *personality,
771 unsigned personalityEncoding,
772 const MCSymbol *lsda,
773 unsigned lsdaEncoding) {
774 MCContext &context = streamer.getContext();
775 const TargetAsmInfo &asmInfo = context.getTargetAsmInfo();
776 bool verboseAsm = streamer.isVerboseAsm();
778 MCSymbol *sectionStart;
779 if (asmInfo.isFunctionEHFrameSymbolPrivate() || !IsEH)
780 sectionStart = context.CreateTempSymbol();
782 sectionStart = context.GetOrCreateSymbol(Twine("EH_frame") + Twine(CIENum));
784 streamer.EmitLabel(sectionStart);
787 MCSymbol *sectionEnd = context.CreateTempSymbol();
790 const MCExpr *Length = MakeStartMinusEndExpr(streamer, *sectionStart,
792 if (verboseAsm) streamer.AddComment("CIE Length");
793 streamer.EmitAbsValue(Length, 4);
796 unsigned CIE_ID = IsEH ? 0 : -1;
797 if (verboseAsm) streamer.AddComment("CIE ID Tag");
798 streamer.EmitIntValue(CIE_ID, 4);
801 if (verboseAsm) streamer.AddComment("DW_CIE_VERSION");
802 streamer.EmitIntValue(dwarf::DW_CIE_VERSION, 1);
804 // Augmentation String
805 SmallString<8> Augmentation;
807 if (verboseAsm) streamer.AddComment("CIE Augmentation");
814 streamer.EmitBytes(Augmentation.str(), 0);
816 streamer.EmitIntValue(0, 1);
818 // Code Alignment Factor
819 if (verboseAsm) streamer.AddComment("CIE Code Alignment Factor");
820 streamer.EmitULEB128IntValue(1);
822 // Data Alignment Factor
823 if (verboseAsm) streamer.AddComment("CIE Data Alignment Factor");
824 streamer.EmitSLEB128IntValue(getDataAlignmentFactor(streamer));
826 // Return Address Register
827 if (verboseAsm) streamer.AddComment("CIE Return Address Column");
828 streamer.EmitULEB128IntValue(asmInfo.getDwarfRARegNum(true));
830 // Augmentation Data Length (optional)
832 unsigned augmentationLength = 0;
835 // Personality Encoding
836 augmentationLength += 1;
838 augmentationLength += getSizeForEncoding(streamer, personalityEncoding);
841 augmentationLength += 1;
842 // Encoding of the FDE pointers
843 augmentationLength += 1;
845 if (verboseAsm) streamer.AddComment("Augmentation Size");
846 streamer.EmitULEB128IntValue(augmentationLength);
848 // Augmentation Data (optional)
850 // Personality Encoding
851 EmitEncodingByte(streamer, personalityEncoding,
852 "Personality Encoding");
854 if (verboseAsm) streamer.AddComment("Personality");
855 EmitPersonality(streamer, *personality, personalityEncoding);
859 EmitEncodingByte(streamer, lsdaEncoding, "LSDA Encoding");
861 // Encoding of the FDE pointers
862 EmitEncodingByte(streamer, asmInfo.getFDEEncoding(UsingCFI),
866 // Initial Instructions
868 const std::vector<MachineMove> &Moves = asmInfo.getInitialFrameState();
869 std::vector<MCCFIInstruction> Instructions;
871 for (int i = 0, n = Moves.size(); i != n; ++i) {
872 MCSymbol *Label = Moves[i].getLabel();
873 const MachineLocation &Dst =
874 TranslateMachineLocation(asmInfo, Moves[i].getDestination());
875 const MachineLocation &Src =
876 TranslateMachineLocation(asmInfo, Moves[i].getSource());
877 MCCFIInstruction Inst(Label, Dst, Src);
878 Instructions.push_back(Inst);
881 EmitCFIInstructions(streamer, Instructions, NULL);
884 streamer.EmitValueToAlignment(IsEH ? 4 : asmInfo.getPointerSize());
886 streamer.EmitLabel(sectionEnd);
887 return *sectionStart;
890 MCSymbol *FrameEmitterImpl::EmitFDE(MCStreamer &streamer,
891 const MCSymbol &cieStart,
892 const MCDwarfFrameInfo &frame) {
893 MCContext &context = streamer.getContext();
894 MCSymbol *fdeStart = context.CreateTempSymbol();
895 MCSymbol *fdeEnd = context.CreateTempSymbol();
896 const TargetAsmInfo &TAsmInfo = context.getTargetAsmInfo();
897 bool verboseAsm = streamer.isVerboseAsm();
899 if (!TAsmInfo.isFunctionEHFrameSymbolPrivate() && IsEH) {
901 context.GetOrCreateSymbol(frame.Function->getName() + Twine(".eh"));
902 streamer.EmitEHSymAttributes(frame.Function, EHSym);
903 streamer.EmitLabel(EHSym);
907 const MCExpr *Length = MakeStartMinusEndExpr(streamer, *fdeStart, *fdeEnd, 0);
908 if (verboseAsm) streamer.AddComment("FDE Length");
909 streamer.EmitAbsValue(Length, 4);
911 streamer.EmitLabel(fdeStart);
914 const MCAsmInfo &asmInfo = context.getAsmInfo();
916 const MCExpr *offset = MakeStartMinusEndExpr(streamer, cieStart, *fdeStart,
918 if (verboseAsm) streamer.AddComment("FDE CIE Offset");
919 streamer.EmitAbsValue(offset, 4);
920 } else if (!asmInfo.doesDwarfRequireRelocationForSectionOffset()) {
921 const MCExpr *offset = MakeStartMinusEndExpr(streamer, *SectionStart,
923 streamer.EmitAbsValue(offset, 4);
925 streamer.EmitSymbolValue(&cieStart, 4);
928 unsigned fdeEncoding = TAsmInfo.getFDEEncoding(UsingCFI);
929 unsigned size = getSizeForEncoding(streamer, fdeEncoding);
932 unsigned PCBeginEncoding = IsEH ? fdeEncoding :
933 (unsigned)dwarf::DW_EH_PE_absptr;
934 unsigned PCBeginSize = getSizeForEncoding(streamer, PCBeginEncoding);
935 EmitSymbol(streamer, *frame.Begin, PCBeginEncoding, "FDE initial location");
938 const MCExpr *Range = MakeStartMinusEndExpr(streamer, *frame.Begin,
940 if (verboseAsm) streamer.AddComment("FDE address range");
941 streamer.EmitAbsValue(Range, size);
944 // Augmentation Data Length
945 unsigned augmentationLength = 0;
948 augmentationLength += getSizeForEncoding(streamer, frame.LsdaEncoding);
950 if (verboseAsm) streamer.AddComment("Augmentation size");
951 streamer.EmitULEB128IntValue(augmentationLength);
955 EmitSymbol(streamer, *frame.Lsda, frame.LsdaEncoding,
956 "Language Specific Data Area");
959 // Call Frame Instructions
961 EmitCFIInstructions(streamer, frame.Instructions, frame.Begin);
964 streamer.EmitValueToAlignment(PCBeginSize);
971 static const CIEKey getEmptyKey() { return CIEKey(0, 0, -1); }
972 static const CIEKey getTombstoneKey() { return CIEKey(0, -1, 0); }
974 CIEKey(const MCSymbol* Personality_, unsigned PersonalityEncoding_,
975 unsigned LsdaEncoding_) : Personality(Personality_),
976 PersonalityEncoding(PersonalityEncoding_),
977 LsdaEncoding(LsdaEncoding_) {
979 const MCSymbol* Personality;
980 unsigned PersonalityEncoding;
981 unsigned LsdaEncoding;
987 struct DenseMapInfo<CIEKey> {
988 static CIEKey getEmptyKey() {
989 return CIEKey::getEmptyKey();
991 static CIEKey getTombstoneKey() {
992 return CIEKey::getTombstoneKey();
994 static unsigned getHashValue(const CIEKey &Key) {
996 ID.AddPointer(Key.Personality);
997 ID.AddInteger(Key.PersonalityEncoding);
998 ID.AddInteger(Key.LsdaEncoding);
999 return ID.ComputeHash();
1001 static bool isEqual(const CIEKey &LHS,
1002 const CIEKey &RHS) {
1003 return LHS.Personality == RHS.Personality &&
1004 LHS.PersonalityEncoding == RHS.PersonalityEncoding &&
1005 LHS.LsdaEncoding == RHS.LsdaEncoding;
1010 void MCDwarfFrameEmitter::Emit(MCStreamer &Streamer,
1013 MCContext &Context = Streamer.getContext();
1014 const TargetAsmInfo &AsmInfo = Context.getTargetAsmInfo();
1015 const MCSection &Section = IsEH ? *AsmInfo.getEHFrameSection() :
1016 *AsmInfo.getDwarfFrameSection();
1017 Streamer.SwitchSection(&Section);
1018 MCSymbol *SectionStart = Context.CreateTempSymbol();
1019 Streamer.EmitLabel(SectionStart);
1021 MCSymbol *FDEEnd = NULL;
1022 DenseMap<CIEKey, const MCSymbol*> CIEStarts;
1023 FrameEmitterImpl Emitter(UsingCFI, IsEH, SectionStart);
1025 const MCSymbol *DummyDebugKey = NULL;
1026 for (unsigned i = 0, n = Streamer.getNumFrameInfos(); i < n; ++i) {
1027 const MCDwarfFrameInfo &Frame = Streamer.getFrameInfo(i);
1028 if (IsEH && AsmInfo.getCompactUnwindSection() &&
1029 Emitter.EmitCompactUnwind(Streamer, Frame)) {
1034 CIEKey Key(Frame.Personality, Frame.PersonalityEncoding,
1035 Frame.LsdaEncoding);
1036 const MCSymbol *&CIEStart = IsEH ? CIEStarts[Key] : DummyDebugKey;
1038 CIEStart = &Emitter.EmitCIE(Streamer, Frame.Personality,
1039 Frame.PersonalityEncoding, Frame.Lsda,
1040 Frame.LsdaEncoding);
1042 FDEEnd = Emitter.EmitFDE(Streamer, *CIEStart, Frame);
1045 Streamer.EmitLabel(FDEEnd);
1048 Streamer.EmitValueToAlignment(AsmInfo.getPointerSize());
1050 Streamer.EmitLabel(FDEEnd);
1053 void MCDwarfFrameEmitter::EmitAdvanceLoc(MCStreamer &Streamer,
1054 uint64_t AddrDelta) {
1055 SmallString<256> Tmp;
1056 raw_svector_ostream OS(Tmp);
1057 MCDwarfFrameEmitter::EncodeAdvanceLoc(AddrDelta, OS);
1058 Streamer.EmitBytes(OS.str(), /*AddrSpace=*/0);
1061 void MCDwarfFrameEmitter::EncodeAdvanceLoc(uint64_t AddrDelta,
1063 // FIXME: Assumes the code alignment factor is 1.
1064 if (AddrDelta == 0) {
1065 } else if (isUIntN(6, AddrDelta)) {
1066 uint8_t Opcode = dwarf::DW_CFA_advance_loc | AddrDelta;
1068 } else if (isUInt<8>(AddrDelta)) {
1069 OS << uint8_t(dwarf::DW_CFA_advance_loc1);
1070 OS << uint8_t(AddrDelta);
1071 } else if (isUInt<16>(AddrDelta)) {
1072 // FIXME: check what is the correct behavior on a big endian machine.
1073 OS << uint8_t(dwarf::DW_CFA_advance_loc2);
1074 OS << uint8_t( AddrDelta & 0xff);
1075 OS << uint8_t((AddrDelta >> 8) & 0xff);
1077 // FIXME: check what is the correct behavior on a big endian machine.
1078 assert(isUInt<32>(AddrDelta));
1079 OS << uint8_t(dwarf::DW_CFA_advance_loc4);
1080 OS << uint8_t( AddrDelta & 0xff);
1081 OS << uint8_t((AddrDelta >> 8) & 0xff);
1082 OS << uint8_t((AddrDelta >> 16) & 0xff);
1083 OS << uint8_t((AddrDelta >> 24) & 0xff);