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/ErrorHandling.h"
22 #include "llvm/Support/raw_ostream.h"
23 #include "llvm/Target/TargetAsmBackend.h"
24 #include "llvm/Target/TargetAsmInfo.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)
54 if (DWARF2_LINE_MIN_INSN_LENGTH == 1)
56 if (AddrDelta % DWARF2_LINE_MIN_INSN_LENGTH != 0) {
57 // TODO: report this error, but really only once.
60 return AddrDelta / DWARF2_LINE_MIN_INSN_LENGTH;
64 // This is called when an instruction is assembled into the specified section
65 // and if there is information from the last .loc directive that has yet to have
66 // a line entry made for it is made.
68 void MCLineEntry::Make(MCStreamer *MCOS, const MCSection *Section) {
69 if (!MCOS->getContext().getDwarfLocSeen())
72 // Create a symbol at in the current section for use in the line entry.
73 MCSymbol *LineSym = MCOS->getContext().CreateTempSymbol();
74 // Set the value of the symbol to use for the MCLineEntry.
75 MCOS->EmitLabel(LineSym);
77 // Get the current .loc info saved in the context.
78 const MCDwarfLoc &DwarfLoc = MCOS->getContext().getCurrentDwarfLoc();
80 // Create a (local) line entry with the symbol and the current .loc info.
81 MCLineEntry LineEntry(LineSym, DwarfLoc);
83 // clear DwarfLocSeen saying the current .loc info is now used.
84 MCOS->getContext().ClearDwarfLocSeen();
86 // Get the MCLineSection for this section, if one does not exist for this
88 const DenseMap<const MCSection *, MCLineSection *> &MCLineSections =
89 MCOS->getContext().getMCLineSections();
90 MCLineSection *LineSection = MCLineSections.lookup(Section);
92 // Create a new MCLineSection. This will be deleted after the dwarf line
93 // table is created using it by iterating through the MCLineSections
95 LineSection = new MCLineSection;
96 // Save a pointer to the new LineSection into the MCLineSections DenseMap.
97 MCOS->getContext().addMCLineSection(Section, LineSection);
100 // Add the line entry to this section's entries.
101 LineSection->addLineEntry(LineEntry);
105 // This helper routine returns an expression of End - Start + IntVal .
107 static inline const MCExpr *MakeStartMinusEndExpr(const MCStreamer &MCOS,
108 const MCSymbol &Start,
111 MCSymbolRefExpr::VariantKind Variant = MCSymbolRefExpr::VK_None;
113 MCSymbolRefExpr::Create(&End, Variant, MCOS.getContext());
115 MCSymbolRefExpr::Create(&Start, Variant, MCOS.getContext());
117 MCBinaryExpr::Create(MCBinaryExpr::Sub, Res, RHS, MCOS.getContext());
119 MCConstantExpr::Create(IntVal, MCOS.getContext());
121 MCBinaryExpr::Create(MCBinaryExpr::Sub, Res1, Res2, MCOS.getContext());
126 // This emits the Dwarf line table for the specified section from the entries
127 // in the LineSection.
129 static inline void EmitDwarfLineTable(MCStreamer *MCOS,
130 const MCSection *Section,
131 const MCLineSection *LineSection) {
132 unsigned FileNum = 1;
133 unsigned LastLine = 1;
135 unsigned Flags = DWARF2_LINE_DEFAULT_IS_STMT ? DWARF2_FLAG_IS_STMT : 0;
137 MCSymbol *LastLabel = NULL;
139 // Loop through each MCLineEntry and encode the dwarf line number table.
140 for (MCLineSection::const_iterator
141 it = LineSection->getMCLineEntries()->begin(),
142 ie = LineSection->getMCLineEntries()->end(); it != ie; ++it) {
144 if (FileNum != it->getFileNum()) {
145 FileNum = it->getFileNum();
146 MCOS->EmitIntValue(dwarf::DW_LNS_set_file, 1);
147 MCOS->EmitULEB128IntValue(FileNum);
149 if (Column != it->getColumn()) {
150 Column = it->getColumn();
151 MCOS->EmitIntValue(dwarf::DW_LNS_set_column, 1);
152 MCOS->EmitULEB128IntValue(Column);
154 if (Isa != it->getIsa()) {
156 MCOS->EmitIntValue(dwarf::DW_LNS_set_isa, 1);
157 MCOS->EmitULEB128IntValue(Isa);
159 if ((it->getFlags() ^ Flags) & DWARF2_FLAG_IS_STMT) {
160 Flags = it->getFlags();
161 MCOS->EmitIntValue(dwarf::DW_LNS_negate_stmt, 1);
163 if (it->getFlags() & DWARF2_FLAG_BASIC_BLOCK)
164 MCOS->EmitIntValue(dwarf::DW_LNS_set_basic_block, 1);
165 if (it->getFlags() & DWARF2_FLAG_PROLOGUE_END)
166 MCOS->EmitIntValue(dwarf::DW_LNS_set_prologue_end, 1);
167 if (it->getFlags() & DWARF2_FLAG_EPILOGUE_BEGIN)
168 MCOS->EmitIntValue(dwarf::DW_LNS_set_epilogue_begin, 1);
170 int64_t LineDelta = static_cast<int64_t>(it->getLine()) - LastLine;
171 MCSymbol *Label = it->getLabel();
173 // At this point we want to emit/create the sequence to encode the delta in
174 // line numbers and the increment of the address from the previous Label
175 // and the current Label.
176 MCOS->EmitDwarfAdvanceLineAddr(LineDelta, LastLabel, Label);
178 LastLine = it->getLine();
182 // Emit a DW_LNE_end_sequence for the end of the section.
183 // Using the pointer Section create a temporary label at the end of the
184 // section and use that and the LastLabel to compute the address delta
185 // and use INT64_MAX as the line delta which is the signal that this is
186 // actually a DW_LNE_end_sequence.
188 // Switch to the section to be able to create a symbol at its end.
189 MCOS->SwitchSection(Section);
191 MCContext &context = MCOS->getContext();
192 // Create a symbol at the end of the section.
193 MCSymbol *SectionEnd = context.CreateTempSymbol();
194 // Set the value of the symbol, as we are at the end of the section.
195 MCOS->EmitLabel(SectionEnd);
197 // Switch back the the dwarf line section.
198 MCOS->SwitchSection(context.getTargetAsmInfo().getDwarfLineSection());
200 MCOS->EmitDwarfAdvanceLineAddr(INT64_MAX, LastLabel, SectionEnd);
204 // This emits the Dwarf file and the line tables.
206 void MCDwarfFileTable::Emit(MCStreamer *MCOS) {
207 MCContext &context = MCOS->getContext();
208 // Switch to the section where the table will be emitted into.
209 MCOS->SwitchSection(context.getTargetAsmInfo().getDwarfLineSection());
211 // Create a symbol at the beginning of this section.
212 MCSymbol *LineStartSym = context.CreateTempSymbol();
213 // Set the value of the symbol, as we are at the start of the section.
214 MCOS->EmitLabel(LineStartSym);
216 // Create a symbol for the end of the section (to be set when we get there).
217 MCSymbol *LineEndSym = context.CreateTempSymbol();
219 // The first 4 bytes is the total length of the information for this
220 // compilation unit (not including these 4 bytes for the length).
221 MCOS->EmitAbsValue(MakeStartMinusEndExpr(*MCOS, *LineStartSym, *LineEndSym,4),
224 // Next 2 bytes is the Version, which is Dwarf 2.
225 MCOS->EmitIntValue(2, 2);
227 // Create a symbol for the end of the prologue (to be set when we get there).
228 MCSymbol *ProEndSym = context.CreateTempSymbol(); // Lprologue_end
230 // Length of the prologue, is the next 4 bytes. Which is the start of the
231 // section to the end of the prologue. Not including the 4 bytes for the
232 // total length, the 2 bytes for the version, and these 4 bytes for the
233 // length of the prologue.
234 MCOS->EmitAbsValue(MakeStartMinusEndExpr(*MCOS, *LineStartSym, *ProEndSym,
238 // Parameters of the state machine, are next.
239 MCOS->EmitIntValue(DWARF2_LINE_MIN_INSN_LENGTH, 1);
240 MCOS->EmitIntValue(DWARF2_LINE_DEFAULT_IS_STMT, 1);
241 MCOS->EmitIntValue(DWARF2_LINE_BASE, 1);
242 MCOS->EmitIntValue(DWARF2_LINE_RANGE, 1);
243 MCOS->EmitIntValue(DWARF2_LINE_OPCODE_BASE, 1);
245 // Standard opcode lengths
246 MCOS->EmitIntValue(0, 1); // length of DW_LNS_copy
247 MCOS->EmitIntValue(1, 1); // length of DW_LNS_advance_pc
248 MCOS->EmitIntValue(1, 1); // length of DW_LNS_advance_line
249 MCOS->EmitIntValue(1, 1); // length of DW_LNS_set_file
250 MCOS->EmitIntValue(1, 1); // length of DW_LNS_set_column
251 MCOS->EmitIntValue(0, 1); // length of DW_LNS_negate_stmt
252 MCOS->EmitIntValue(0, 1); // length of DW_LNS_set_basic_block
253 MCOS->EmitIntValue(0, 1); // length of DW_LNS_const_add_pc
254 MCOS->EmitIntValue(1, 1); // length of DW_LNS_fixed_advance_pc
255 MCOS->EmitIntValue(0, 1); // length of DW_LNS_set_prologue_end
256 MCOS->EmitIntValue(0, 1); // length of DW_LNS_set_epilogue_begin
257 MCOS->EmitIntValue(1, 1); // DW_LNS_set_isa
259 // Put out the directory and file tables.
261 // First the directory table.
262 const std::vector<StringRef> &MCDwarfDirs =
263 context.getMCDwarfDirs();
264 for (unsigned i = 0; i < MCDwarfDirs.size(); i++) {
265 MCOS->EmitBytes(MCDwarfDirs[i], 0); // the DirectoryName
266 MCOS->EmitBytes(StringRef("\0", 1), 0); // the null term. of the string
268 MCOS->EmitIntValue(0, 1); // Terminate the directory list
270 // Second the file table.
271 const std::vector<MCDwarfFile *> &MCDwarfFiles =
272 MCOS->getContext().getMCDwarfFiles();
273 for (unsigned i = 1; i < MCDwarfFiles.size(); i++) {
274 MCOS->EmitBytes(MCDwarfFiles[i]->getName(), 0); // FileName
275 MCOS->EmitBytes(StringRef("\0", 1), 0); // the null term. of the string
277 MCOS->EmitULEB128IntValue(MCDwarfFiles[i]->getDirIndex());
278 MCOS->EmitIntValue(0, 1); // last modification timestamp (always 0)
279 MCOS->EmitIntValue(0, 1); // filesize (always 0)
281 MCOS->EmitIntValue(0, 1); // Terminate the file list
283 // This is the end of the prologue, so set the value of the symbol at the
284 // end of the prologue (that was used in a previous expression).
285 MCOS->EmitLabel(ProEndSym);
287 // Put out the line tables.
288 const DenseMap<const MCSection *, MCLineSection *> &MCLineSections =
289 MCOS->getContext().getMCLineSections();
290 const std::vector<const MCSection *> &MCLineSectionOrder =
291 MCOS->getContext().getMCLineSectionOrder();
292 for (std::vector<const MCSection*>::const_iterator it =
293 MCLineSectionOrder.begin(), ie = MCLineSectionOrder.end(); it != ie;
295 const MCSection *Sec = *it;
296 const MCLineSection *Line = MCLineSections.lookup(Sec);
297 EmitDwarfLineTable(MCOS, Sec, Line);
299 // Now delete the MCLineSections that were created in MCLineEntry::Make()
300 // and used to emit the line table.
304 if (MCOS->getContext().getAsmInfo().getLinkerRequiresNonEmptyDwarfLines()
305 && MCLineSectionOrder.begin() == MCLineSectionOrder.end()) {
306 // The darwin9 linker has a bug (see PR8715). For for 32-bit architectures
308 // total_length >= prologue_length + 10
309 // We are 4 bytes short, since we have total_length = 51 and
310 // prologue_length = 45
312 // The regular end_sequence should be sufficient.
313 MCDwarfLineAddr::Emit(MCOS, INT64_MAX, 0);
316 // This is the end of the section, so set the value of the symbol at the end
317 // of this section (that was used in a previous expression).
318 MCOS->EmitLabel(LineEndSym);
321 /// Utility function to write the encoding to an object writer.
322 void MCDwarfLineAddr::Write(MCObjectWriter *OW, int64_t LineDelta,
323 uint64_t AddrDelta) {
324 SmallString<256> Tmp;
325 raw_svector_ostream OS(Tmp);
326 MCDwarfLineAddr::Encode(LineDelta, AddrDelta, OS);
327 OW->WriteBytes(OS.str());
330 /// Utility function to emit the encoding to a streamer.
331 void MCDwarfLineAddr::Emit(MCStreamer *MCOS, int64_t LineDelta,
332 uint64_t AddrDelta) {
333 SmallString<256> Tmp;
334 raw_svector_ostream OS(Tmp);
335 MCDwarfLineAddr::Encode(LineDelta, AddrDelta, OS);
336 MCOS->EmitBytes(OS.str(), /*AddrSpace=*/0);
339 /// Utility function to encode a Dwarf pair of LineDelta and AddrDeltas.
340 void MCDwarfLineAddr::Encode(int64_t LineDelta, uint64_t AddrDelta,
342 uint64_t Temp, Opcode;
343 bool NeedCopy = false;
345 // Scale the address delta by the minimum instruction length.
346 AddrDelta = ScaleAddrDelta(AddrDelta);
348 // A LineDelta of INT64_MAX is a signal that this is actually a
349 // DW_LNE_end_sequence. We cannot use special opcodes here, since we want the
350 // end_sequence to emit the matrix entry.
351 if (LineDelta == INT64_MAX) {
352 if (AddrDelta == MAX_SPECIAL_ADDR_DELTA)
353 OS << char(dwarf::DW_LNS_const_add_pc);
355 OS << char(dwarf::DW_LNS_advance_pc);
357 raw_svector_ostream OSE(Tmp);
358 MCObjectWriter::EncodeULEB128(AddrDelta, OSE);
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) {
467 unsigned size = getSizeForEncoding(streamer, symbolEncoding);
468 unsigned application = symbolEncoding & 0x70;
469 switch (application) {
471 assert(0 && "Unknown Encoding");
474 streamer.EmitSymbolValue(&symbol, size);
476 case dwarf::DW_EH_PE_pcrel:
477 streamer.EmitPCRelSymbolValue(&symbol, size);
482 static const MachineLocation TranslateMachineLocation(
483 const TargetAsmInfo &AsmInfo,
484 const MachineLocation &Loc) {
485 unsigned Reg = Loc.getReg() == MachineLocation::VirtualFP ?
486 MachineLocation::VirtualFP :
487 unsigned(AsmInfo.getDwarfRegNum(Loc.getReg(), true));
488 const MachineLocation &NewLoc = Loc.isReg() ?
489 MachineLocation(Reg) : MachineLocation(Reg, Loc.getOffset());
494 class FrameEmitterImpl {
498 FrameEmitterImpl() : CFAOffset(0) {
501 const MCSymbol &EmitCIE(MCStreamer &streamer,
502 const MCSymbol *personality,
503 unsigned personalityEncoding,
504 const MCSymbol *lsda,
505 unsigned lsdaEncoding);
506 MCSymbol *EmitFDE(MCStreamer &streamer,
507 const MCSymbol &cieStart,
508 const MCDwarfFrameInfo &frame);
509 void EmitCFIInstructions(MCStreamer &streamer,
510 const std::vector<MCCFIInstruction> &Instrs,
511 MCSymbol *BaseLabel);
512 void EmitCFIInstruction(MCStreamer &Streamer,
513 const MCCFIInstruction &Instr);
517 void FrameEmitterImpl::EmitCFIInstruction(MCStreamer &Streamer,
518 const MCCFIInstruction &Instr) {
519 int dataAlignmentFactor = getDataAlignmentFactor(Streamer);
521 switch (Instr.getOperation()) {
522 case MCCFIInstruction::Move:
523 case MCCFIInstruction::RelMove: {
524 const MachineLocation &Dst = Instr.getDestination();
525 const MachineLocation &Src = Instr.getSource();
526 const bool IsRelative = Instr.getOperation() == MCCFIInstruction::RelMove;
529 if (Dst.isReg() && Dst.getReg() == MachineLocation::VirtualFP) {
530 assert(!Src.isReg() && "Machine move not supported yet.");
532 if (Src.getReg() == MachineLocation::VirtualFP) {
533 Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa_offset, 1);
535 Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa, 1);
536 Streamer.EmitULEB128IntValue(Src.getReg());
540 CFAOffset += Src.getOffset();
542 CFAOffset = -Src.getOffset();
544 Streamer.EmitULEB128IntValue(CFAOffset);
548 if (Src.isReg() && Src.getReg() == MachineLocation::VirtualFP) {
549 assert(Dst.isReg() && "Machine move not supported yet.");
550 Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa_register, 1);
551 Streamer.EmitULEB128IntValue(Dst.getReg());
555 unsigned Reg = Src.getReg();
557 int Offset = Dst.getOffset();
560 Offset = Offset / dataAlignmentFactor;
563 Streamer.EmitIntValue(dwarf::DW_CFA_offset_extended_sf, 1);
564 Streamer.EmitULEB128IntValue(Reg);
565 Streamer.EmitSLEB128IntValue(Offset);
566 } else if (Reg < 64) {
567 Streamer.EmitIntValue(dwarf::DW_CFA_offset + Reg, 1);
568 Streamer.EmitULEB128IntValue(Offset);
570 Streamer.EmitIntValue(dwarf::DW_CFA_offset_extended, 1);
571 Streamer.EmitULEB128IntValue(Reg);
572 Streamer.EmitULEB128IntValue(Offset);
576 case MCCFIInstruction::Remember:
577 Streamer.EmitIntValue(dwarf::DW_CFA_remember_state, 1);
579 case MCCFIInstruction::Restore:
580 Streamer.EmitIntValue(dwarf::DW_CFA_restore_state, 1);
582 case MCCFIInstruction::SameValue: {
583 unsigned Reg = Instr.getDestination().getReg();
584 Streamer.EmitIntValue(dwarf::DW_CFA_same_value, 1);
585 Streamer.EmitULEB128IntValue(Reg);
589 llvm_unreachable("Unhandled case in switch");
592 /// EmitFrameMoves - Emit frame instructions to describe the layout of the
594 void FrameEmitterImpl::EmitCFIInstructions(MCStreamer &streamer,
595 const std::vector<MCCFIInstruction> &Instrs,
596 MCSymbol *BaseLabel) {
597 for (unsigned i = 0, N = Instrs.size(); i < N; ++i) {
598 const MCCFIInstruction &Instr = Instrs[i];
599 MCSymbol *Label = Instr.getLabel();
600 // Throw out move if the label is invalid.
601 if (Label && !Label->isDefined()) continue; // Not emitted, in dead code.
603 // Advance row if new location.
604 if (BaseLabel && Label) {
605 MCSymbol *ThisSym = Label;
606 if (ThisSym != BaseLabel) {
607 streamer.EmitDwarfAdvanceFrameAddr(BaseLabel, ThisSym);
612 EmitCFIInstruction(streamer, Instr);
616 const MCSymbol &FrameEmitterImpl::EmitCIE(MCStreamer &streamer,
617 const MCSymbol *personality,
618 unsigned personalityEncoding,
619 const MCSymbol *lsda,
620 unsigned lsdaEncoding) {
621 MCContext &context = streamer.getContext();
622 const TargetAsmInfo &asmInfo = context.getTargetAsmInfo();
623 const MCSection §ion = *asmInfo.getEHFrameSection();
624 streamer.SwitchSection(§ion);
625 MCSymbol *sectionStart = streamer.getContext().CreateTempSymbol();
626 MCSymbol *sectionEnd = streamer.getContext().CreateTempSymbol();
629 const MCExpr *Length = MakeStartMinusEndExpr(streamer, *sectionStart,
631 streamer.EmitLabel(sectionStart);
632 streamer.EmitValue(Length, 4);
635 streamer.EmitIntValue(0, 4);
638 streamer.EmitIntValue(dwarf::DW_CIE_VERSION, 1);
640 // Augmentation String
641 SmallString<8> Augmentation;
648 streamer.EmitBytes(Augmentation.str(), 0);
649 streamer.EmitIntValue(0, 1);
651 // Code Alignment Factor
652 streamer.EmitULEB128IntValue(1);
654 // Data Alignment Factor
655 streamer.EmitSLEB128IntValue(getDataAlignmentFactor(streamer));
657 // Return Address Register
658 streamer.EmitULEB128IntValue(asmInfo.getDwarfRARegNum(true));
660 // Augmentation Data Length (optional)
661 MCSymbol *augmentationStart = streamer.getContext().CreateTempSymbol();
662 MCSymbol *augmentationEnd = streamer.getContext().CreateTempSymbol();
663 const MCExpr *augmentationLength = MakeStartMinusEndExpr(streamer,
665 *augmentationEnd, 0);
666 streamer.EmitULEB128Value(augmentationLength);
668 // Augmentation Data (optional)
669 streamer.EmitLabel(augmentationStart);
671 // Personality Encoding
672 streamer.EmitIntValue(personalityEncoding, 1);
674 EmitSymbol(streamer, *personality, personalityEncoding);
678 streamer.EmitIntValue(lsdaEncoding, 1);
680 // Encoding of the FDE pointers
681 streamer.EmitIntValue(asmInfo.getFDEEncoding(), 1);
682 streamer.EmitLabel(augmentationEnd);
684 // Initial Instructions
686 const std::vector<MachineMove> Moves = asmInfo.getInitialFrameState();
687 std::vector<MCCFIInstruction> Instructions;
689 for (int i = 0, n = Moves.size(); i != n; ++i) {
690 MCSymbol *Label = Moves[i].getLabel();
691 const MachineLocation &Dst =
692 TranslateMachineLocation(asmInfo, Moves[i].getDestination());
693 const MachineLocation &Src =
694 TranslateMachineLocation(asmInfo, Moves[i].getSource());
695 MCCFIInstruction Inst(Label, Dst, Src);
696 Instructions.push_back(Inst);
699 EmitCFIInstructions(streamer, Instructions, NULL);
702 streamer.EmitValueToAlignment(4);
704 streamer.EmitLabel(sectionEnd);
705 return *sectionStart;
708 MCSymbol *FrameEmitterImpl::EmitFDE(MCStreamer &streamer,
709 const MCSymbol &cieStart,
710 const MCDwarfFrameInfo &frame) {
711 MCContext &context = streamer.getContext();
712 MCSymbol *fdeStart = context.CreateTempSymbol();
713 MCSymbol *fdeEnd = context.CreateTempSymbol();
714 const TargetAsmInfo &asmInfo = context.getTargetAsmInfo();
717 const MCExpr *Length = MakeStartMinusEndExpr(streamer, *fdeStart, *fdeEnd, 0);
718 streamer.EmitValue(Length, 4);
720 streamer.EmitLabel(fdeStart);
722 const MCExpr *offset = MakeStartMinusEndExpr(streamer, cieStart, *fdeStart,
724 streamer.EmitValue(offset, 4);
725 unsigned fdeEncoding = asmInfo.getFDEEncoding();
726 unsigned size = getSizeForEncoding(streamer, fdeEncoding);
729 streamer.EmitPCRelSymbolValue(frame.Begin, size);
732 const MCExpr *Range = MakeStartMinusEndExpr(streamer, *frame.Begin,
734 streamer.EmitValue(Range, size);
736 // Augmentation Data Length
737 MCSymbol *augmentationStart = streamer.getContext().CreateTempSymbol();
738 MCSymbol *augmentationEnd = streamer.getContext().CreateTempSymbol();
739 const MCExpr *augmentationLength = MakeStartMinusEndExpr(streamer,
741 *augmentationEnd, 0);
742 streamer.EmitULEB128Value(augmentationLength);
745 streamer.EmitLabel(augmentationStart);
747 EmitSymbol(streamer, *frame.Lsda, frame.LsdaEncoding);
748 streamer.EmitLabel(augmentationEnd);
749 // Call Frame Instructions
751 EmitCFIInstructions(streamer, frame.Instructions, frame.Begin);
754 streamer.EmitValueToAlignment(4);
761 static const CIEKey getEmptyKey() { return CIEKey(0, 0, -1); }
762 static const CIEKey getTombstoneKey() { return CIEKey(0, -1, 0); }
764 CIEKey(const MCSymbol* Personality_, unsigned PersonalityEncoding_,
765 unsigned LsdaEncoding_) : Personality(Personality_),
766 PersonalityEncoding(PersonalityEncoding_),
767 LsdaEncoding(LsdaEncoding_) {
769 const MCSymbol* Personality;
770 unsigned PersonalityEncoding;
771 unsigned LsdaEncoding;
777 struct DenseMapInfo<CIEKey> {
778 static CIEKey getEmptyKey() {
779 return CIEKey::getEmptyKey();
781 static CIEKey getTombstoneKey() {
782 return CIEKey::getTombstoneKey();
784 static unsigned getHashValue(const CIEKey &Key) {
786 ID.AddPointer(Key.Personality);
787 ID.AddInteger(Key.PersonalityEncoding);
788 ID.AddInteger(Key.LsdaEncoding);
789 return ID.ComputeHash();
791 static bool isEqual(const CIEKey &LHS,
793 return LHS.Personality == RHS.Personality &&
794 LHS.PersonalityEncoding == RHS.PersonalityEncoding &&
795 LHS.LsdaEncoding == RHS.LsdaEncoding;
800 void MCDwarfFrameEmitter::Emit(MCStreamer &streamer) {
801 const MCContext &context = streamer.getContext();
802 const TargetAsmInfo &asmInfo = context.getTargetAsmInfo();
803 MCSymbol *fdeEnd = NULL;
804 DenseMap<CIEKey, const MCSymbol*> CIEStarts;
805 FrameEmitterImpl Emitter;
807 for (unsigned i = 0, n = streamer.getNumFrameInfos(); i < n; ++i) {
808 const MCDwarfFrameInfo &frame = streamer.getFrameInfo(i);
809 CIEKey key(frame.Personality, frame.PersonalityEncoding,
811 const MCSymbol *&cieStart = CIEStarts[key];
813 cieStart = &Emitter.EmitCIE(streamer, frame.Personality,
814 frame.PersonalityEncoding, frame.Lsda,
816 fdeEnd = Emitter.EmitFDE(streamer, *cieStart, frame);
818 streamer.EmitLabel(fdeEnd);
821 streamer.EmitValueToAlignment(asmInfo.getPointerSize());
823 streamer.EmitLabel(fdeEnd);
826 void MCDwarfFrameEmitter::EmitAdvanceLoc(MCStreamer &Streamer,
827 uint64_t AddrDelta) {
828 SmallString<256> Tmp;
829 raw_svector_ostream OS(Tmp);
830 MCDwarfFrameEmitter::EncodeAdvanceLoc(AddrDelta, OS);
831 Streamer.EmitBytes(OS.str(), /*AddrSpace=*/0);
834 void MCDwarfFrameEmitter::EncodeAdvanceLoc(uint64_t AddrDelta,
836 // FIXME: Assumes the code alignment factor is 1.
837 if (AddrDelta == 0) {
838 } else if (isUIntN(6, AddrDelta)) {
839 uint8_t Opcode = dwarf::DW_CFA_advance_loc | AddrDelta;
841 } else if (isUInt<8>(AddrDelta)) {
842 OS << uint8_t(dwarf::DW_CFA_advance_loc1);
843 OS << uint8_t(AddrDelta);
844 } else if (isUInt<16>(AddrDelta)) {
845 // FIXME: check what is the correct behavior on a big endian machine.
846 OS << uint8_t(dwarf::DW_CFA_advance_loc2);
847 OS << uint8_t( AddrDelta & 0xff);
848 OS << uint8_t((AddrDelta >> 8) & 0xff);
850 // FIXME: check what is the correct behavior on a big endian machine.
851 assert(isUInt<32>(AddrDelta));
852 OS << uint8_t(dwarf::DW_CFA_advance_loc4);
853 OS << uint8_t( AddrDelta & 0xff);
854 OS << uint8_t((AddrDelta >> 8) & 0xff);
855 OS << uint8_t((AddrDelta >> 16) & 0xff);
856 OS << uint8_t((AddrDelta >> 24) & 0xff);