1 //===- lib/MC/MCDwarf.cpp - MCDwarf implementation ------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 #include "llvm/ADT/FoldingSet.h"
11 #include "llvm/MC/MCAsmInfo.h"
12 #include "llvm/MC/MCDwarf.h"
13 #include "llvm/MC/MCAssembler.h"
14 #include "llvm/MC/MCStreamer.h"
15 #include "llvm/MC/MCSymbol.h"
16 #include "llvm/MC/MCExpr.h"
17 #include "llvm/MC/MCContext.h"
18 #include "llvm/MC/MCObjectWriter.h"
19 #include "llvm/ADT/SmallString.h"
20 #include "llvm/Support/Debug.h"
21 #include "llvm/Support/raw_ostream.h"
22 #include "llvm/Target/TargetAsmBackend.h"
23 #include "llvm/Target/TargetAsmInfo.h"
26 // Given a special op, return the address skip amount (in units of
27 // DWARF2_LINE_MIN_INSN_LENGTH.
28 #define SPECIAL_ADDR(op) (((op) - DWARF2_LINE_OPCODE_BASE)/DWARF2_LINE_RANGE)
30 // The maximum address skip amount that can be encoded with a special op.
31 #define MAX_SPECIAL_ADDR_DELTA SPECIAL_ADDR(255)
33 // First special line opcode - leave room for the standard opcodes.
34 // Note: If you want to change this, you'll have to update the
35 // "standard_opcode_lengths" table that is emitted in DwarfFileTable::Emit().
36 #define DWARF2_LINE_OPCODE_BASE 13
38 // Minimum line offset in a special line info. opcode. This value
39 // was chosen to give a reasonable range of values.
40 #define DWARF2_LINE_BASE -5
42 // Range of line offsets in a special line info. opcode.
43 # define DWARF2_LINE_RANGE 14
45 // Define the architecture-dependent minimum instruction length (in bytes).
46 // This value should be rather too small than too big.
47 # define DWARF2_LINE_MIN_INSN_LENGTH 1
49 // Note: when DWARF2_LINE_MIN_INSN_LENGTH == 1 which is the current setting,
50 // this routine is a nop and will be optimized away.
51 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);
356 raw_svector_ostream OSE(Tmp);
357 MCObjectWriter::EncodeULEB128(AddrDelta, OSE);
360 OS << char(dwarf::DW_LNS_extended_op);
362 OS << char(dwarf::DW_LNE_end_sequence);
366 // Bias the line delta by the base.
367 Temp = LineDelta - DWARF2_LINE_BASE;
369 // If the line increment is out of range of a special opcode, we must encode
370 // it with DW_LNS_advance_line.
371 if (Temp >= DWARF2_LINE_RANGE) {
372 OS << char(dwarf::DW_LNS_advance_line);
374 raw_svector_ostream OSE(Tmp);
375 MCObjectWriter::EncodeSLEB128(LineDelta, OSE);
379 Temp = 0 - DWARF2_LINE_BASE;
383 // Use DW_LNS_copy instead of a "line +0, addr +0" special opcode.
384 if (LineDelta == 0 && AddrDelta == 0) {
385 OS << char(dwarf::DW_LNS_copy);
389 // Bias the opcode by the special opcode base.
390 Temp += DWARF2_LINE_OPCODE_BASE;
392 // Avoid overflow when addr_delta is large.
393 if (AddrDelta < 256 + MAX_SPECIAL_ADDR_DELTA) {
394 // Try using a special opcode.
395 Opcode = Temp + AddrDelta * DWARF2_LINE_RANGE;
401 // Try using DW_LNS_const_add_pc followed by special op.
402 Opcode = Temp + (AddrDelta - MAX_SPECIAL_ADDR_DELTA) * DWARF2_LINE_RANGE;
404 OS << char(dwarf::DW_LNS_const_add_pc);
410 // Otherwise use DW_LNS_advance_pc.
411 OS << char(dwarf::DW_LNS_advance_pc);
413 raw_svector_ostream OSE(Tmp);
414 MCObjectWriter::EncodeULEB128(AddrDelta, OSE);
418 OS << char(dwarf::DW_LNS_copy);
423 void MCDwarfFile::print(raw_ostream &OS) const {
424 OS << '"' << getName() << '"';
427 void MCDwarfFile::dump() const {
431 static int getDataAlignmentFactor(MCStreamer &streamer) {
432 MCContext &context = streamer.getContext();
433 const TargetAsmInfo &asmInfo = context.getTargetAsmInfo();
434 int size = asmInfo.getPointerSize();
435 if (asmInfo.getStackGrowthDirection() == TargetFrameInfo::StackGrowsUp)
441 /// EmitFrameMoves - Emit frame instructions to describe the layout of the
443 static void EmitFrameMoves(MCStreamer &streamer,
444 const std::vector<MachineMove> &Moves,
445 MCSymbol *BaseLabel, bool isEH) {
446 MCContext &context = streamer.getContext();
447 const TargetAsmInfo &asmInfo = context.getTargetAsmInfo();
448 int dataAlignmentFactor = getDataAlignmentFactor(streamer);
450 for (unsigned i = 0, N = Moves.size(); i < N; ++i) {
451 const MachineMove &Move = Moves[i];
452 MCSymbol *Label = Move.getLabel();
453 // Throw out move if the label is invalid.
454 if (Label && !Label->isDefined()) continue; // Not emitted, in dead code.
456 const MachineLocation &Dst = Move.getDestination();
457 const MachineLocation &Src = Move.getSource();
459 // Advance row if new location.
460 if (BaseLabel && Label) {
461 MCSymbol *ThisSym = Label;
462 if (ThisSym != BaseLabel) {
463 // FIXME: We should relax this instead of using a DW_CFA_advance_loc4
464 // for every address change!
465 streamer.EmitIntValue(dwarf::DW_CFA_advance_loc4, 1);
466 const MCExpr *Length = MakeStartMinusEndExpr(streamer, *BaseLabel,
468 streamer.EmitValue(Length, 4);
474 if (Dst.isReg() && Dst.getReg() == MachineLocation::VirtualFP) {
475 assert(!Src.isReg() && "Machine move not supported yet.");
477 if (Src.getReg() == MachineLocation::VirtualFP) {
478 streamer.EmitIntValue(dwarf::DW_CFA_def_cfa_offset, 1);
480 streamer.EmitIntValue(dwarf::DW_CFA_def_cfa, 1);
481 streamer.EmitULEB128IntValue(asmInfo.getDwarfRegNum(Src.getReg(),
485 streamer.EmitULEB128IntValue(-Src.getOffset(), 1);
489 if (Src.isReg() && Src.getReg() == MachineLocation::VirtualFP) {
490 assert(Dst.isReg() && "Machine move not supported yet.");
491 streamer.EmitIntValue(dwarf::DW_CFA_def_cfa_register, 1);
492 streamer.EmitULEB128IntValue(asmInfo.getDwarfRegNum(Dst.getReg(), isEH));
496 unsigned Reg = asmInfo.getDwarfRegNum(Src.getReg(), isEH);
497 int Offset = Dst.getOffset() / dataAlignmentFactor;
500 streamer.EmitIntValue(dwarf::DW_CFA_offset_extended_sf, 1);
501 streamer.EmitULEB128IntValue(Reg);
502 streamer.EmitSLEB128IntValue(Offset);
503 } else if (Reg < 64) {
504 streamer.EmitIntValue(dwarf::DW_CFA_offset + Reg, 1);
505 streamer.EmitULEB128IntValue(Offset, 1);
507 streamer.EmitIntValue(dwarf::DW_CFA_offset_extended, 1);
508 streamer.EmitULEB128IntValue(Reg, 1);
509 streamer.EmitULEB128IntValue(Offset, 1);
514 static void EmitSymbol(MCStreamer &streamer, const MCSymbol &symbol,
515 unsigned symbolEncoding) {
516 MCContext &context = streamer.getContext();
517 const TargetAsmInfo &asmInfo = context.getTargetAsmInfo();
518 unsigned format = symbolEncoding & 0x0f;
519 unsigned application = symbolEncoding & 0xf0;
523 assert(0 && "Unknown Encoding");
525 case dwarf::DW_EH_PE_absptr:
526 case dwarf::DW_EH_PE_signed:
527 size = asmInfo.getPointerSize();
529 case dwarf::DW_EH_PE_udata2:
530 case dwarf::DW_EH_PE_sdata2:
533 case dwarf::DW_EH_PE_udata4:
534 case dwarf::DW_EH_PE_sdata4:
537 case dwarf::DW_EH_PE_udata8:
538 case dwarf::DW_EH_PE_sdata8:
542 switch (application) {
544 assert(0 && "Unknown Encoding");
547 case dwarf::DW_EH_PE_indirect:
548 streamer.EmitSymbolValue(&symbol, size);
550 case dwarf::DW_EH_PE_pcrel:
551 streamer.EmitPCRelSymbolValue(&symbol, size);
556 static const MCSymbol &EmitCIE(MCStreamer &streamer,
557 const MCSymbol *personality,
558 unsigned personalityEncoding,
559 const MCSymbol *lsda,
560 unsigned lsdaEncoding) {
561 MCContext &context = streamer.getContext();
562 const TargetAsmInfo &asmInfo = context.getTargetAsmInfo();
563 const MCSection §ion = *asmInfo.getEHFrameSection();
564 streamer.SwitchSection(§ion);
565 MCSymbol *sectionStart = streamer.getContext().CreateTempSymbol();
566 MCSymbol *sectionEnd = streamer.getContext().CreateTempSymbol();
569 const MCExpr *Length = MakeStartMinusEndExpr(streamer, *sectionStart,
571 streamer.EmitLabel(sectionStart);
572 streamer.EmitValue(Length, 4);
575 streamer.EmitIntValue(0, 4);
578 streamer.EmitIntValue(dwarf::DW_CIE_VERSION, 1);
580 // Augmentation String
581 SmallString<8> Augmentation;
588 streamer.EmitBytes(Augmentation.str(), 0);
589 streamer.EmitIntValue(0, 1);
591 // Code Alignment Factor
592 streamer.EmitULEB128IntValue(1);
594 // Data Alignment Factor
595 streamer.EmitSLEB128IntValue(getDataAlignmentFactor(streamer));
597 // Return Address Register
598 streamer.EmitULEB128IntValue(asmInfo.getDwarfRARegNum(true));
600 // Augmentation Data Length (optional)
601 MCSymbol *augmentationStart = streamer.getContext().CreateTempSymbol();
602 MCSymbol *augmentationEnd = streamer.getContext().CreateTempSymbol();
603 const MCExpr *augmentationLength = MakeStartMinusEndExpr(streamer,
605 *augmentationEnd, 0);
606 streamer.EmitULEB128Value(augmentationLength);
608 // Augmentation Data (optional)
609 streamer.EmitLabel(augmentationStart);
611 // Personality Encoding
612 streamer.EmitIntValue(personalityEncoding, 1);
614 EmitSymbol(streamer, *personality, personalityEncoding);
618 streamer.EmitIntValue(lsdaEncoding, 1);
620 // Encoding of the FDE pointers
621 streamer.EmitIntValue(dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4, 1);
622 streamer.EmitLabel(augmentationEnd);
624 // Initial Instructions
626 const std::vector<MachineMove> Moves = asmInfo.getInitialFrameState();
628 EmitFrameMoves(streamer, Moves, NULL, true);
631 streamer.EmitValueToAlignment(4);
633 streamer.EmitLabel(sectionEnd);
634 return *sectionStart;
637 static MCSymbol *EmitFDE(MCStreamer &streamer,
638 const MCSymbol &cieStart,
639 const MCDwarfFrameInfo &frame) {
640 MCContext &context = streamer.getContext();
641 MCSymbol *fdeStart = context.CreateTempSymbol();
642 MCSymbol *fdeEnd = context.CreateTempSymbol();
645 const MCExpr *Length = MakeStartMinusEndExpr(streamer, *fdeStart, *fdeEnd, 0);
646 streamer.EmitValue(Length, 4);
648 streamer.EmitLabel(fdeStart);
650 const MCExpr *offset = MakeStartMinusEndExpr(streamer, cieStart, *fdeStart,
652 streamer.EmitValue(offset, 4);
655 streamer.EmitPCRelSymbolValue(frame.Begin, 4);
658 const MCExpr *Range = MakeStartMinusEndExpr(streamer, *frame.Begin,
660 streamer.EmitValue(Range, 4);
662 // Augmentation Data Length
663 MCSymbol *augmentationStart = streamer.getContext().CreateTempSymbol();
664 MCSymbol *augmentationEnd = streamer.getContext().CreateTempSymbol();
665 const MCExpr *augmentationLength = MakeStartMinusEndExpr(streamer,
667 *augmentationEnd, 0);
668 streamer.EmitULEB128Value(augmentationLength);
671 streamer.EmitLabel(augmentationStart);
673 EmitSymbol(streamer, *frame.Lsda, frame.LsdaEncoding);
674 streamer.EmitLabel(augmentationEnd);
675 // Call Frame Instructions
677 EmitFrameMoves(streamer, frame.Moves, frame.Begin, true);
680 streamer.EmitValueToAlignment(4);
686 static const CIEKey EmptyKey;
687 static const CIEKey TombstoneKey;
689 CIEKey(const MCSymbol* Personality_, unsigned PersonalityEncoding_,
690 unsigned LsdaEncoding_) : Personality(Personality_),
691 PersonalityEncoding(PersonalityEncoding_),
692 LsdaEncoding(LsdaEncoding_) {
694 const MCSymbol* Personality;
695 unsigned PersonalityEncoding;
696 unsigned LsdaEncoding;
699 const CIEKey CIEKey::EmptyKey(0, 0, -1);
700 const CIEKey CIEKey::TombstoneKey(0, -1, 0);
704 struct DenseMapInfo<CIEKey> {
705 static CIEKey getEmptyKey() {
706 return CIEKey::EmptyKey;
708 static CIEKey getTombstoneKey() {
709 return CIEKey::TombstoneKey;
711 static unsigned getHashValue(const CIEKey &Key) {
713 ID.AddPointer(Key.Personality);
714 ID.AddInteger(Key.PersonalityEncoding);
715 ID.AddInteger(Key.LsdaEncoding);
716 return ID.ComputeHash();
718 static bool isEqual(const CIEKey &LHS,
720 return LHS.Personality == RHS.Personality &&
721 LHS.PersonalityEncoding == RHS.PersonalityEncoding &&
722 LHS.LsdaEncoding == RHS.LsdaEncoding;
727 void MCDwarfFrameEmitter::Emit(MCStreamer &streamer) {
728 const MCContext &context = streamer.getContext();
729 const TargetAsmInfo &asmInfo = context.getTargetAsmInfo();
730 MCSymbol *fdeEnd = NULL;
731 DenseMap<CIEKey, const MCSymbol*> CIEStarts;
733 for (unsigned i = 0, n = streamer.getNumFrameInfos(); i < n; ++i) {
734 const MCDwarfFrameInfo &frame = streamer.getFrameInfo(i);
735 CIEKey key(frame.Personality, frame.PersonalityEncoding,
737 const MCSymbol *&cieStart = CIEStarts[key];
739 cieStart = &EmitCIE(streamer, frame.Personality,
740 frame.PersonalityEncoding, frame.Lsda,
742 fdeEnd = EmitFDE(streamer, *cieStart, frame);
744 streamer.EmitLabel(fdeEnd);
747 streamer.EmitValueToAlignment(asmInfo.getPointerSize());
749 streamer.EmitLabel(fdeEnd);