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 MCOS->EmitDwarfAdvanceLineAddr(LineDelta, LastLabel, Label);
177 LastLine = it->getLine();
181 // Emit a DW_LNE_end_sequence for the end of the section.
182 // Using the pointer Section create a temporary label at the end of the
183 // section and use that and the LastLabel to compute the address delta
184 // and use INT64_MAX as the line delta which is the signal that this is
185 // actually a DW_LNE_end_sequence.
187 // Switch to the section to be able to create a symbol at its end.
188 MCOS->SwitchSection(Section);
190 MCContext &context = MCOS->getContext();
191 // Create a symbol at the end of the section.
192 MCSymbol *SectionEnd = context.CreateTempSymbol();
193 // Set the value of the symbol, as we are at the end of the section.
194 MCOS->EmitLabel(SectionEnd);
196 // Switch back the the dwarf line section.
197 MCOS->SwitchSection(context.getTargetAsmInfo().getDwarfLineSection());
199 MCOS->EmitDwarfAdvanceLineAddr(INT64_MAX, LastLabel, SectionEnd);
203 // This emits the Dwarf file and the line tables.
205 void MCDwarfFileTable::Emit(MCStreamer *MCOS) {
206 MCContext &context = MCOS->getContext();
207 // Switch to the section where the table will be emitted into.
208 MCOS->SwitchSection(context.getTargetAsmInfo().getDwarfLineSection());
210 // Create a symbol at the beginning of this section.
211 MCSymbol *LineStartSym = context.CreateTempSymbol();
212 // Set the value of the symbol, as we are at the start of the section.
213 MCOS->EmitLabel(LineStartSym);
215 // Create a symbol for the end of the section (to be set when we get there).
216 MCSymbol *LineEndSym = context.CreateTempSymbol();
218 // The first 4 bytes is the total length of the information for this
219 // compilation unit (not including these 4 bytes for the length).
220 MCOS->EmitAbsValue(MakeStartMinusEndExpr(*MCOS, *LineStartSym, *LineEndSym,4),
223 // Next 2 bytes is the Version, which is Dwarf 2.
224 MCOS->EmitIntValue(2, 2);
226 // Create a symbol for the end of the prologue (to be set when we get there).
227 MCSymbol *ProEndSym = context.CreateTempSymbol(); // Lprologue_end
229 // Length of the prologue, is the next 4 bytes. Which is the start of the
230 // section to the end of the prologue. Not including the 4 bytes for the
231 // total length, the 2 bytes for the version, and these 4 bytes for the
232 // length of the prologue.
233 MCOS->EmitAbsValue(MakeStartMinusEndExpr(*MCOS, *LineStartSym, *ProEndSym,
237 // Parameters of the state machine, are next.
238 MCOS->EmitIntValue(DWARF2_LINE_MIN_INSN_LENGTH, 1);
239 MCOS->EmitIntValue(DWARF2_LINE_DEFAULT_IS_STMT, 1);
240 MCOS->EmitIntValue(DWARF2_LINE_BASE, 1);
241 MCOS->EmitIntValue(DWARF2_LINE_RANGE, 1);
242 MCOS->EmitIntValue(DWARF2_LINE_OPCODE_BASE, 1);
244 // Standard opcode lengths
245 MCOS->EmitIntValue(0, 1); // length of DW_LNS_copy
246 MCOS->EmitIntValue(1, 1); // length of DW_LNS_advance_pc
247 MCOS->EmitIntValue(1, 1); // length of DW_LNS_advance_line
248 MCOS->EmitIntValue(1, 1); // length of DW_LNS_set_file
249 MCOS->EmitIntValue(1, 1); // length of DW_LNS_set_column
250 MCOS->EmitIntValue(0, 1); // length of DW_LNS_negate_stmt
251 MCOS->EmitIntValue(0, 1); // length of DW_LNS_set_basic_block
252 MCOS->EmitIntValue(0, 1); // length of DW_LNS_const_add_pc
253 MCOS->EmitIntValue(1, 1); // length of DW_LNS_fixed_advance_pc
254 MCOS->EmitIntValue(0, 1); // length of DW_LNS_set_prologue_end
255 MCOS->EmitIntValue(0, 1); // length of DW_LNS_set_epilogue_begin
256 MCOS->EmitIntValue(1, 1); // DW_LNS_set_isa
258 // Put out the directory and file tables.
260 // First the directory table.
261 const std::vector<StringRef> &MCDwarfDirs =
262 context.getMCDwarfDirs();
263 for (unsigned i = 0; i < MCDwarfDirs.size(); i++) {
264 MCOS->EmitBytes(MCDwarfDirs[i], 0); // the DirectoryName
265 MCOS->EmitBytes(StringRef("\0", 1), 0); // the null term. of the string
267 MCOS->EmitIntValue(0, 1); // Terminate the directory list
269 // Second the file table.
270 const std::vector<MCDwarfFile *> &MCDwarfFiles =
271 MCOS->getContext().getMCDwarfFiles();
272 for (unsigned i = 1; i < MCDwarfFiles.size(); i++) {
273 MCOS->EmitBytes(MCDwarfFiles[i]->getName(), 0); // FileName
274 MCOS->EmitBytes(StringRef("\0", 1), 0); // the null term. of the string
276 MCOS->EmitULEB128IntValue(MCDwarfFiles[i]->getDirIndex());
277 MCOS->EmitIntValue(0, 1); // last modification timestamp (always 0)
278 MCOS->EmitIntValue(0, 1); // filesize (always 0)
280 MCOS->EmitIntValue(0, 1); // Terminate the file list
282 // This is the end of the prologue, so set the value of the symbol at the
283 // end of the prologue (that was used in a previous expression).
284 MCOS->EmitLabel(ProEndSym);
286 // Put out the line tables.
287 const DenseMap<const MCSection *, MCLineSection *> &MCLineSections =
288 MCOS->getContext().getMCLineSections();
289 const std::vector<const MCSection *> &MCLineSectionOrder =
290 MCOS->getContext().getMCLineSectionOrder();
291 for (std::vector<const MCSection*>::const_iterator it =
292 MCLineSectionOrder.begin(), ie = MCLineSectionOrder.end(); it != ie;
294 const MCSection *Sec = *it;
295 const MCLineSection *Line = MCLineSections.lookup(Sec);
296 EmitDwarfLineTable(MCOS, Sec, Line);
298 // Now delete the MCLineSections that were created in MCLineEntry::Make()
299 // and used to emit the line table.
303 if (MCOS->getContext().getAsmInfo().getLinkerRequiresNonEmptyDwarfLines()
304 && MCLineSectionOrder.begin() == MCLineSectionOrder.end()) {
305 // The darwin9 linker has a bug (see PR8715). For for 32-bit architectures
307 // total_length >= prologue_length + 10
308 // We are 4 bytes short, since we have total_length = 51 and
309 // prologue_length = 45
311 // The regular end_sequence should be sufficient.
312 MCDwarfLineAddr::Emit(MCOS, INT64_MAX, 0);
315 // This is the end of the section, so set the value of the symbol at the end
316 // of this section (that was used in a previous expression).
317 MCOS->EmitLabel(LineEndSym);
320 /// Utility function to write the encoding to an object writer.
321 void MCDwarfLineAddr::Write(MCObjectWriter *OW, int64_t LineDelta,
322 uint64_t AddrDelta) {
323 SmallString<256> Tmp;
324 raw_svector_ostream OS(Tmp);
325 MCDwarfLineAddr::Encode(LineDelta, AddrDelta, OS);
326 OW->WriteBytes(OS.str());
329 /// Utility function to emit the encoding to a streamer.
330 void MCDwarfLineAddr::Emit(MCStreamer *MCOS, int64_t LineDelta,
331 uint64_t AddrDelta) {
332 SmallString<256> Tmp;
333 raw_svector_ostream OS(Tmp);
334 MCDwarfLineAddr::Encode(LineDelta, AddrDelta, OS);
335 MCOS->EmitBytes(OS.str(), /*AddrSpace=*/0);
338 /// Utility function to encode a Dwarf pair of LineDelta and AddrDeltas.
339 void MCDwarfLineAddr::Encode(int64_t LineDelta, uint64_t AddrDelta,
341 uint64_t Temp, Opcode;
342 bool NeedCopy = false;
344 // Scale the address delta by the minimum instruction length.
345 AddrDelta = ScaleAddrDelta(AddrDelta);
347 // A LineDelta of INT64_MAX is a signal that this is actually a
348 // DW_LNE_end_sequence. We cannot use special opcodes here, since we want the
349 // end_sequence to emit the matrix entry.
350 if (LineDelta == INT64_MAX) {
351 if (AddrDelta == MAX_SPECIAL_ADDR_DELTA)
352 OS << char(dwarf::DW_LNS_const_add_pc);
354 OS << char(dwarf::DW_LNS_advance_pc);
355 MCObjectWriter::EncodeULEB128(AddrDelta, OS);
357 OS << char(dwarf::DW_LNS_extended_op);
359 OS << char(dwarf::DW_LNE_end_sequence);
363 // Bias the line delta by the base.
364 Temp = LineDelta - DWARF2_LINE_BASE;
366 // If the line increment is out of range of a special opcode, we must encode
367 // it with DW_LNS_advance_line.
368 if (Temp >= DWARF2_LINE_RANGE) {
369 OS << char(dwarf::DW_LNS_advance_line);
371 raw_svector_ostream OSE(Tmp);
372 MCObjectWriter::EncodeSLEB128(LineDelta, OSE);
376 Temp = 0 - DWARF2_LINE_BASE;
380 // Use DW_LNS_copy instead of a "line +0, addr +0" special opcode.
381 if (LineDelta == 0 && AddrDelta == 0) {
382 OS << char(dwarf::DW_LNS_copy);
386 // Bias the opcode by the special opcode base.
387 Temp += DWARF2_LINE_OPCODE_BASE;
389 // Avoid overflow when addr_delta is large.
390 if (AddrDelta < 256 + MAX_SPECIAL_ADDR_DELTA) {
391 // Try using a special opcode.
392 Opcode = Temp + AddrDelta * DWARF2_LINE_RANGE;
398 // Try using DW_LNS_const_add_pc followed by special op.
399 Opcode = Temp + (AddrDelta - MAX_SPECIAL_ADDR_DELTA) * DWARF2_LINE_RANGE;
401 OS << char(dwarf::DW_LNS_const_add_pc);
407 // Otherwise use DW_LNS_advance_pc.
408 OS << char(dwarf::DW_LNS_advance_pc);
410 raw_svector_ostream OSE(Tmp);
411 MCObjectWriter::EncodeULEB128(AddrDelta, OSE);
415 OS << char(dwarf::DW_LNS_copy);
420 void MCDwarfFile::print(raw_ostream &OS) const {
421 OS << '"' << getName() << '"';
424 void MCDwarfFile::dump() const {
428 static int getDataAlignmentFactor(MCStreamer &streamer) {
429 MCContext &context = streamer.getContext();
430 const TargetAsmInfo &asmInfo = context.getTargetAsmInfo();
431 int size = asmInfo.getPointerSize();
432 if (asmInfo.getStackGrowthDirection() == TargetFrameLowering::StackGrowsUp)
438 static unsigned getSizeForEncoding(MCStreamer &streamer,
439 unsigned symbolEncoding) {
440 MCContext &context = streamer.getContext();
441 const TargetAsmInfo &asmInfo = context.getTargetAsmInfo();
442 unsigned format = symbolEncoding & 0x0f;
445 assert(0 && "Unknown Encoding");
446 case dwarf::DW_EH_PE_absptr:
447 case dwarf::DW_EH_PE_signed:
448 return asmInfo.getPointerSize();
449 case dwarf::DW_EH_PE_udata2:
450 case dwarf::DW_EH_PE_sdata2:
452 case dwarf::DW_EH_PE_udata4:
453 case dwarf::DW_EH_PE_sdata4:
455 case dwarf::DW_EH_PE_udata8:
456 case dwarf::DW_EH_PE_sdata8:
461 static void EmitSymbol(MCStreamer &streamer, const MCSymbol &symbol,
462 unsigned symbolEncoding, const char *comment = 0) {
463 MCContext &context = streamer.getContext();
464 const MCAsmInfo &asmInfo = context.getAsmInfo();
465 const MCExpr *v = asmInfo.getExprForFDESymbol(&symbol,
468 unsigned size = getSizeForEncoding(streamer, symbolEncoding);
469 if (streamer.isVerboseAsm() && comment) streamer.AddComment(comment);
470 streamer.EmitAbsValue(v, size);
473 static void EmitPersonality(MCStreamer &streamer, const MCSymbol &symbol,
474 unsigned symbolEncoding) {
475 MCContext &context = streamer.getContext();
476 const MCAsmInfo &asmInfo = context.getAsmInfo();
477 const MCExpr *v = asmInfo.getExprForPersonalitySymbol(&symbol,
480 unsigned size = getSizeForEncoding(streamer, symbolEncoding);
481 streamer.EmitValue(v, size);
484 static const MachineLocation TranslateMachineLocation(
485 const TargetAsmInfo &AsmInfo,
486 const MachineLocation &Loc) {
487 unsigned Reg = Loc.getReg() == MachineLocation::VirtualFP ?
488 MachineLocation::VirtualFP :
489 unsigned(AsmInfo.getDwarfRegNum(Loc.getReg(), true));
490 const MachineLocation &NewLoc = Loc.isReg() ?
491 MachineLocation(Reg) : MachineLocation(Reg, Loc.getOffset());
496 class FrameEmitterImpl {
501 const MCSymbol *SectionStart;
504 FrameEmitterImpl(bool usingCFI, bool isEH, const MCSymbol *sectionStart) :
505 CFAOffset(0), CIENum(0), UsingCFI(usingCFI), IsEH(isEH),
506 SectionStart(sectionStart) {
509 /// EmitCompactUnwind - Emit the unwind information in a compact way. If
510 /// we're successful, return 'true'. Otherwise, return 'false' and it will
511 /// emit the normal CIE and FDE.
512 bool EmitCompactUnwind(MCStreamer &streamer,
513 const MCDwarfFrameInfo &frame);
515 const MCSymbol &EmitCIE(MCStreamer &streamer,
516 const MCSymbol *personality,
517 unsigned personalityEncoding,
518 const MCSymbol *lsda,
519 unsigned lsdaEncoding);
520 MCSymbol *EmitFDE(MCStreamer &streamer,
521 const MCSymbol &cieStart,
522 const MCDwarfFrameInfo &frame);
523 void EmitCFIInstructions(MCStreamer &streamer,
524 const std::vector<MCCFIInstruction> &Instrs,
525 MCSymbol *BaseLabel);
526 void EmitCFIInstruction(MCStreamer &Streamer,
527 const MCCFIInstruction &Instr);
530 } // end anonymous namespace
532 static void EmitEncodingByte(MCStreamer &Streamer, unsigned Encoding,
534 if (Streamer.isVerboseAsm()) {
535 const char *EncStr = 0;
537 default: EncStr = "<unknown encoding>";
538 case dwarf::DW_EH_PE_absptr: EncStr = "absptr";
539 case dwarf::DW_EH_PE_omit: EncStr = "omit";
540 case dwarf::DW_EH_PE_pcrel: EncStr = "pcrel";
541 case dwarf::DW_EH_PE_udata4: EncStr = "udata4";
542 case dwarf::DW_EH_PE_udata8: EncStr = "udata8";
543 case dwarf::DW_EH_PE_sdata4: EncStr = "sdata4";
544 case dwarf::DW_EH_PE_sdata8: EncStr = "sdata8";
545 case dwarf::DW_EH_PE_pcrel |dwarf::DW_EH_PE_udata4: EncStr = "pcrel udata4";
546 case dwarf::DW_EH_PE_pcrel |dwarf::DW_EH_PE_sdata4: EncStr = "pcrel sdata4";
547 case dwarf::DW_EH_PE_pcrel |dwarf::DW_EH_PE_udata8: EncStr = "pcrel udata8";
548 case dwarf::DW_EH_PE_pcrel |dwarf::DW_EH_PE_sdata8: EncStr = "pcrel sdata8";
549 case dwarf::DW_EH_PE_indirect |dwarf::DW_EH_PE_pcrel|dwarf::DW_EH_PE_udata4:
550 EncStr = "indirect pcrel udata4";
551 case dwarf::DW_EH_PE_indirect |dwarf::DW_EH_PE_pcrel|dwarf::DW_EH_PE_sdata4:
552 EncStr = "indirect pcrel sdata4";
553 case dwarf::DW_EH_PE_indirect |dwarf::DW_EH_PE_pcrel|dwarf::DW_EH_PE_udata8:
554 EncStr = "indirect pcrel udata8";
555 case dwarf::DW_EH_PE_indirect |dwarf::DW_EH_PE_pcrel|dwarf::DW_EH_PE_sdata8:
556 EncStr = "indirect pcrel sdata8";
559 Streamer.AddComment(Twine(Prefix) + " = " + EncStr);
562 Streamer.EmitIntValue(Encoding, 1);
565 void FrameEmitterImpl::EmitCFIInstruction(MCStreamer &Streamer,
566 const MCCFIInstruction &Instr) {
567 int dataAlignmentFactor = getDataAlignmentFactor(Streamer);
568 bool VerboseAsm = Streamer.isVerboseAsm();
570 switch (Instr.getOperation()) {
571 case MCCFIInstruction::Move:
572 case MCCFIInstruction::RelMove: {
573 const MachineLocation &Dst = Instr.getDestination();
574 const MachineLocation &Src = Instr.getSource();
575 const bool IsRelative = Instr.getOperation() == MCCFIInstruction::RelMove;
578 if (Dst.isReg() && Dst.getReg() == MachineLocation::VirtualFP) {
579 if (Src.getReg() == MachineLocation::VirtualFP) {
580 if (VerboseAsm) Streamer.AddComment("DW_CFA_def_cfa_offset");
581 Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa_offset, 1);
583 if (VerboseAsm) Streamer.AddComment("DW_CFA_def_cfa");
584 Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa, 1);
585 if (VerboseAsm) Streamer.AddComment(Twine("Reg ") +
586 Twine(Src.getReg()));
587 Streamer.EmitULEB128IntValue(Src.getReg());
591 CFAOffset += Src.getOffset();
593 CFAOffset = -Src.getOffset();
595 if (VerboseAsm) Streamer.AddComment(Twine("Offset " + Twine(CFAOffset)));
596 Streamer.EmitULEB128IntValue(CFAOffset);
600 if (Src.isReg() && Src.getReg() == MachineLocation::VirtualFP) {
601 assert(Dst.isReg() && "Machine move not supported yet.");
602 if (VerboseAsm) Streamer.AddComment("DW_CFA_def_cfa_register");
603 Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa_register, 1);
604 if (VerboseAsm) Streamer.AddComment(Twine("Reg ") + Twine(Dst.getReg()));
605 Streamer.EmitULEB128IntValue(Dst.getReg());
609 unsigned Reg = Src.getReg();
610 int Offset = Dst.getOffset();
613 Offset = Offset / dataAlignmentFactor;
616 if (VerboseAsm) Streamer.AddComment("DW_CFA_offset_extended_sf");
617 Streamer.EmitIntValue(dwarf::DW_CFA_offset_extended_sf, 1);
618 if (VerboseAsm) Streamer.AddComment(Twine("Reg ") + Twine(Reg));
619 Streamer.EmitULEB128IntValue(Reg);
620 if (VerboseAsm) Streamer.AddComment(Twine("Offset ") + Twine(Offset));
621 Streamer.EmitSLEB128IntValue(Offset);
622 } else if (Reg < 64) {
623 if (VerboseAsm) Streamer.AddComment(Twine("DW_CFA_offset + Reg(") +
625 Streamer.EmitIntValue(dwarf::DW_CFA_offset + Reg, 1);
626 if (VerboseAsm) Streamer.AddComment(Twine("Offset ") + Twine(Offset));
627 Streamer.EmitULEB128IntValue(Offset);
629 if (VerboseAsm) Streamer.AddComment("DW_CFA_offset_extended");
630 Streamer.EmitIntValue(dwarf::DW_CFA_offset_extended, 1);
631 if (VerboseAsm) Streamer.AddComment(Twine("Reg ") + Twine(Reg));
632 Streamer.EmitULEB128IntValue(Reg);
633 if (VerboseAsm) Streamer.AddComment(Twine("Offset ") + Twine(Offset));
634 Streamer.EmitULEB128IntValue(Offset);
638 case MCCFIInstruction::Remember:
639 if (VerboseAsm) Streamer.AddComment("DW_CFA_remember_state");
640 Streamer.EmitIntValue(dwarf::DW_CFA_remember_state, 1);
642 case MCCFIInstruction::Restore:
643 if (VerboseAsm) Streamer.AddComment("DW_CFA_restore_state");
644 Streamer.EmitIntValue(dwarf::DW_CFA_restore_state, 1);
646 case MCCFIInstruction::SameValue: {
647 unsigned Reg = Instr.getDestination().getReg();
648 if (VerboseAsm) Streamer.AddComment("DW_CFA_same_value");
649 Streamer.EmitIntValue(dwarf::DW_CFA_same_value, 1);
650 if (VerboseAsm) Streamer.AddComment(Twine("Reg ") + Twine(Reg));
651 Streamer.EmitULEB128IntValue(Reg);
655 llvm_unreachable("Unhandled case in switch");
658 /// EmitFrameMoves - Emit frame instructions to describe the layout of the
660 void FrameEmitterImpl::EmitCFIInstructions(MCStreamer &streamer,
661 const std::vector<MCCFIInstruction> &Instrs,
662 MCSymbol *BaseLabel) {
663 for (unsigned i = 0, N = Instrs.size(); i < N; ++i) {
664 const MCCFIInstruction &Instr = Instrs[i];
665 MCSymbol *Label = Instr.getLabel();
666 // Throw out move if the label is invalid.
667 if (Label && !Label->isDefined()) continue; // Not emitted, in dead code.
669 // Advance row if new location.
670 if (BaseLabel && Label) {
671 MCSymbol *ThisSym = Label;
672 if (ThisSym != BaseLabel) {
673 if (streamer.isVerboseAsm()) streamer.AddComment("DW_CFA_advance_loc4");
674 streamer.EmitDwarfAdvanceFrameAddr(BaseLabel, ThisSym);
679 EmitCFIInstruction(streamer, Instr);
683 /// EmitCompactUnwind - Emit the unwind information in a compact way. If we're
684 /// successful, return 'true'. Otherwise, return 'false' and it will emit the
685 /// normal CIE and FDE.
686 bool FrameEmitterImpl::EmitCompactUnwind(MCStreamer &Streamer,
687 const MCDwarfFrameInfo &Frame) {
691 MCContext &Context = Streamer.getContext();
692 const TargetAsmInfo &TAI = Context.getTargetAsmInfo();
693 bool VerboseAsm = Streamer.isVerboseAsm();
695 // range-start range-length compact-unwind-enc personality-func lsda
696 // _foo LfooEnd-_foo 0x00000023 0 0
697 // _bar LbarEnd-_bar 0x00000025 __gxx_personality except_tab1
699 // .section __LD,__compact_unwind,regular,debug
701 // # compact unwind for _foo
703 // .set L1,LfooEnd-_foo
709 // # compact unwind for _bar
711 // .set L2,LbarEnd-_bar
714 // .quad __gxx_personality
717 Streamer.SwitchSection(TAI.getCompactUnwindSection());
720 unsigned FDEEncoding = TAI.getFDEEncoding(UsingCFI);
721 unsigned Size = getSizeForEncoding(Streamer, FDEEncoding);
722 if (VerboseAsm) Streamer.AddComment("Range Start");
723 Streamer.EmitSymbolValue(Frame.Function, Size);
726 const MCExpr *Range = MakeStartMinusEndExpr(Streamer, *Frame.Begin,
728 if (VerboseAsm) Streamer.AddComment("Range Length");
729 Streamer.EmitAbsValue(Range, 4);
733 const std::vector<MachineMove> &Moves = TAI.getInitialFrameState();
734 uint32_t Encoding = 0;
735 Size = getSizeForEncoding(Streamer, dwarf::DW_EH_PE_udata4);
736 if (VerboseAsm) Streamer.AddComment("Compact Unwind Encoding");
737 Streamer.EmitIntValue(Encoding, Size);
739 // Personality Function
740 Size = getSizeForEncoding(Streamer, Frame.PersonalityEncoding);
741 if (VerboseAsm) Streamer.AddComment("Personality Function");
742 if (Frame.Personality)
743 Streamer.EmitSymbolValue(Frame.Personality, Size);
745 Streamer.EmitIntValue(0, Size); // No personality fn
748 Size = getSizeForEncoding(Streamer, Frame.LsdaEncoding);
749 if (VerboseAsm) Streamer.AddComment("LSDA");
751 Streamer.EmitSymbolValue(Frame.Lsda, Size);
753 Streamer.EmitIntValue(0, Size); // No LSDA
759 const MCSymbol &FrameEmitterImpl::EmitCIE(MCStreamer &streamer,
760 const MCSymbol *personality,
761 unsigned personalityEncoding,
762 const MCSymbol *lsda,
763 unsigned lsdaEncoding) {
764 MCContext &context = streamer.getContext();
765 const TargetAsmInfo &asmInfo = context.getTargetAsmInfo();
766 bool verboseAsm = streamer.isVerboseAsm();
768 MCSymbol *sectionStart;
769 if (asmInfo.isFunctionEHFrameSymbolPrivate() || !IsEH)
770 sectionStart = context.CreateTempSymbol();
772 sectionStart = context.GetOrCreateSymbol(Twine("EH_frame") + Twine(CIENum));
774 streamer.EmitLabel(sectionStart);
777 MCSymbol *sectionEnd = streamer.getContext().CreateTempSymbol();
780 const MCExpr *Length = MakeStartMinusEndExpr(streamer, *sectionStart,
782 if (verboseAsm) streamer.AddComment("CIE Length");
783 streamer.EmitAbsValue(Length, 4);
786 unsigned CIE_ID = IsEH ? 0 : -1;
787 if (verboseAsm) streamer.AddComment("CIE ID Tag");
788 streamer.EmitIntValue(CIE_ID, 4);
791 if (verboseAsm) streamer.AddComment("DW_CIE_VERSION");
792 streamer.EmitIntValue(dwarf::DW_CIE_VERSION, 1);
794 // Augmentation String
795 SmallString<8> Augmentation;
797 if (verboseAsm) streamer.AddComment("CIE Augmentation");
804 streamer.EmitBytes(Augmentation.str(), 0);
806 streamer.EmitIntValue(0, 1);
808 // Code Alignment Factor
809 if (verboseAsm) streamer.AddComment("CIE Code Alignment Factor");
810 streamer.EmitULEB128IntValue(1);
812 // Data Alignment Factor
813 if (verboseAsm) streamer.AddComment("CIE Data Alignment Factor");
814 streamer.EmitSLEB128IntValue(getDataAlignmentFactor(streamer));
816 // Return Address Register
817 if (verboseAsm) streamer.AddComment("CIE Return Address Column");
818 streamer.EmitULEB128IntValue(asmInfo.getDwarfRARegNum(true));
820 // Augmentation Data Length (optional)
822 unsigned augmentationLength = 0;
825 // Personality Encoding
826 augmentationLength += 1;
828 augmentationLength += getSizeForEncoding(streamer, personalityEncoding);
831 augmentationLength += 1;
832 // Encoding of the FDE pointers
833 augmentationLength += 1;
835 if (verboseAsm) streamer.AddComment("Augmentation Size");
836 streamer.EmitULEB128IntValue(augmentationLength);
838 // Augmentation Data (optional)
840 // Personality Encoding
841 EmitEncodingByte(streamer, personalityEncoding,
842 "Personality Encoding");
844 if (verboseAsm) streamer.AddComment("Personality");
845 EmitPersonality(streamer, *personality, personalityEncoding);
849 EmitEncodingByte(streamer, lsdaEncoding, "LSDA Encoding");
851 // Encoding of the FDE pointers
852 EmitEncodingByte(streamer, asmInfo.getFDEEncoding(UsingCFI),
856 // Initial Instructions
858 const std::vector<MachineMove> &Moves = asmInfo.getInitialFrameState();
859 std::vector<MCCFIInstruction> Instructions;
861 for (int i = 0, n = Moves.size(); i != n; ++i) {
862 MCSymbol *Label = Moves[i].getLabel();
863 const MachineLocation &Dst =
864 TranslateMachineLocation(asmInfo, Moves[i].getDestination());
865 const MachineLocation &Src =
866 TranslateMachineLocation(asmInfo, Moves[i].getSource());
867 MCCFIInstruction Inst(Label, Dst, Src);
868 Instructions.push_back(Inst);
871 EmitCFIInstructions(streamer, Instructions, NULL);
874 streamer.EmitValueToAlignment(IsEH ? 4 : asmInfo.getPointerSize());
876 streamer.EmitLabel(sectionEnd);
877 return *sectionStart;
880 MCSymbol *FrameEmitterImpl::EmitFDE(MCStreamer &streamer,
881 const MCSymbol &cieStart,
882 const MCDwarfFrameInfo &frame) {
883 MCContext &context = streamer.getContext();
884 MCSymbol *fdeStart = context.CreateTempSymbol();
885 MCSymbol *fdeEnd = context.CreateTempSymbol();
886 const TargetAsmInfo &TAsmInfo = context.getTargetAsmInfo();
887 bool verboseAsm = streamer.isVerboseAsm();
889 if (!TAsmInfo.isFunctionEHFrameSymbolPrivate() && IsEH) {
891 context.GetOrCreateSymbol(frame.Function->getName() + Twine(".eh"));
892 streamer.EmitEHSymAttributes(frame.Function, EHSym);
893 streamer.EmitLabel(EHSym);
897 const MCExpr *Length = MakeStartMinusEndExpr(streamer, *fdeStart, *fdeEnd, 0);
898 if (verboseAsm) streamer.AddComment("FDE Length");
899 streamer.EmitAbsValue(Length, 4);
901 streamer.EmitLabel(fdeStart);
904 const MCAsmInfo &asmInfo = context.getAsmInfo();
906 const MCExpr *offset = MakeStartMinusEndExpr(streamer, cieStart, *fdeStart,
908 if (verboseAsm) streamer.AddComment("FDE CIE Offset");
909 streamer.EmitAbsValue(offset, 4);
910 } else if (!asmInfo.doesDwarfRequireRelocationForSectionOffset()) {
911 const MCExpr *offset = MakeStartMinusEndExpr(streamer, *SectionStart,
913 streamer.EmitAbsValue(offset, 4);
915 streamer.EmitSymbolValue(&cieStart, 4);
918 unsigned fdeEncoding = TAsmInfo.getFDEEncoding(UsingCFI);
919 unsigned size = getSizeForEncoding(streamer, fdeEncoding);
922 unsigned PCBeginEncoding = IsEH ? fdeEncoding :
923 (unsigned)dwarf::DW_EH_PE_absptr;
924 unsigned PCBeginSize = getSizeForEncoding(streamer, PCBeginEncoding);
925 EmitSymbol(streamer, *frame.Begin, PCBeginEncoding, "FDE initial location");
928 const MCExpr *Range = MakeStartMinusEndExpr(streamer, *frame.Begin,
930 if (verboseAsm) streamer.AddComment("FDE address range");
931 streamer.EmitAbsValue(Range, size);
934 // Augmentation Data Length
935 unsigned augmentationLength = 0;
938 augmentationLength += getSizeForEncoding(streamer, frame.LsdaEncoding);
940 if (verboseAsm) streamer.AddComment("Augmentation size");
941 streamer.EmitULEB128IntValue(augmentationLength);
945 EmitSymbol(streamer, *frame.Lsda, frame.LsdaEncoding,
946 "Language Specific Data Area");
949 // Call Frame Instructions
951 EmitCFIInstructions(streamer, frame.Instructions, frame.Begin);
954 streamer.EmitValueToAlignment(PCBeginSize);
961 static const CIEKey getEmptyKey() { return CIEKey(0, 0, -1); }
962 static const CIEKey getTombstoneKey() { return CIEKey(0, -1, 0); }
964 CIEKey(const MCSymbol* Personality_, unsigned PersonalityEncoding_,
965 unsigned LsdaEncoding_) : Personality(Personality_),
966 PersonalityEncoding(PersonalityEncoding_),
967 LsdaEncoding(LsdaEncoding_) {
969 const MCSymbol* Personality;
970 unsigned PersonalityEncoding;
971 unsigned LsdaEncoding;
977 struct DenseMapInfo<CIEKey> {
978 static CIEKey getEmptyKey() {
979 return CIEKey::getEmptyKey();
981 static CIEKey getTombstoneKey() {
982 return CIEKey::getTombstoneKey();
984 static unsigned getHashValue(const CIEKey &Key) {
986 ID.AddPointer(Key.Personality);
987 ID.AddInteger(Key.PersonalityEncoding);
988 ID.AddInteger(Key.LsdaEncoding);
989 return ID.ComputeHash();
991 static bool isEqual(const CIEKey &LHS,
993 return LHS.Personality == RHS.Personality &&
994 LHS.PersonalityEncoding == RHS.PersonalityEncoding &&
995 LHS.LsdaEncoding == RHS.LsdaEncoding;
1000 void MCDwarfFrameEmitter::Emit(MCStreamer &Streamer,
1003 MCContext &Context = Streamer.getContext();
1004 const TargetAsmInfo &AsmInfo = Context.getTargetAsmInfo();
1005 const MCSection &Section = IsEH ? *AsmInfo.getEHFrameSection() :
1006 *AsmInfo.getDwarfFrameSection();
1007 Streamer.SwitchSection(&Section);
1008 MCSymbol *SectionStart = Context.CreateTempSymbol();
1009 Streamer.EmitLabel(SectionStart);
1011 MCSymbol *FDEEnd = NULL;
1012 DenseMap<CIEKey, const MCSymbol*> CIEStarts;
1013 FrameEmitterImpl Emitter(UsingCFI, IsEH, SectionStart);
1015 const MCSymbol *DummyDebugKey = NULL;
1016 for (unsigned i = 0, n = Streamer.getNumFrameInfos(); i < n; ++i) {
1017 const MCDwarfFrameInfo &Frame = Streamer.getFrameInfo(i);
1018 if (IsEH && AsmInfo.getCompactUnwindSection() &&
1019 Emitter.EmitCompactUnwind(Streamer, Frame))
1022 CIEKey Key(Frame.Personality, Frame.PersonalityEncoding,
1023 Frame.LsdaEncoding);
1024 const MCSymbol *&CIEStart = IsEH ? CIEStarts[Key] : DummyDebugKey;
1026 CIEStart = &Emitter.EmitCIE(Streamer, Frame.Personality,
1027 Frame.PersonalityEncoding, Frame.Lsda,
1028 Frame.LsdaEncoding);
1030 FDEEnd = Emitter.EmitFDE(Streamer, *CIEStart, Frame);
1033 Streamer.EmitLabel(FDEEnd);
1036 Streamer.EmitValueToAlignment(AsmInfo.getPointerSize());
1038 Streamer.EmitLabel(FDEEnd);
1041 void MCDwarfFrameEmitter::EmitAdvanceLoc(MCStreamer &Streamer,
1042 uint64_t AddrDelta) {
1043 SmallString<256> Tmp;
1044 raw_svector_ostream OS(Tmp);
1045 MCDwarfFrameEmitter::EncodeAdvanceLoc(AddrDelta, OS);
1046 Streamer.EmitBytes(OS.str(), /*AddrSpace=*/0);
1049 void MCDwarfFrameEmitter::EncodeAdvanceLoc(uint64_t AddrDelta,
1051 // FIXME: Assumes the code alignment factor is 1.
1052 if (AddrDelta == 0) {
1053 } else if (isUIntN(6, AddrDelta)) {
1054 uint8_t Opcode = dwarf::DW_CFA_advance_loc | AddrDelta;
1056 } else if (isUInt<8>(AddrDelta)) {
1057 OS << uint8_t(dwarf::DW_CFA_advance_loc1);
1058 OS << uint8_t(AddrDelta);
1059 } else if (isUInt<16>(AddrDelta)) {
1060 // FIXME: check what is the correct behavior on a big endian machine.
1061 OS << uint8_t(dwarf::DW_CFA_advance_loc2);
1062 OS << uint8_t( AddrDelta & 0xff);
1063 OS << uint8_t((AddrDelta >> 8) & 0xff);
1065 // FIXME: check what is the correct behavior on a big endian machine.
1066 assert(isUInt<32>(AddrDelta));
1067 OS << uint8_t(dwarf::DW_CFA_advance_loc4);
1068 OS << uint8_t( AddrDelta & 0xff);
1069 OS << uint8_t((AddrDelta >> 8) & 0xff);
1070 OS << uint8_t((AddrDelta >> 16) & 0xff);
1071 OS << uint8_t((AddrDelta >> 24) & 0xff);