1 //===- lib/MC/MCDwarf.cpp - MCDwarf implementation ------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 #include "llvm/MC/MCDwarf.h"
11 #include "llvm/ADT/Hashing.h"
12 #include "llvm/ADT/SmallString.h"
13 #include "llvm/ADT/Twine.h"
14 #include "llvm/Config/config.h"
15 #include "llvm/MC/MCAsmInfo.h"
16 #include "llvm/MC/MCContext.h"
17 #include "llvm/MC/MCExpr.h"
18 #include "llvm/MC/MCObjectFileInfo.h"
19 #include "llvm/MC/MCObjectWriter.h"
20 #include "llvm/MC/MCRegisterInfo.h"
21 #include "llvm/MC/MCStreamer.h"
22 #include "llvm/MC/MCSymbol.h"
23 #include "llvm/Support/Debug.h"
24 #include "llvm/Support/ErrorHandling.h"
25 #include "llvm/Support/LEB128.h"
26 #include "llvm/Support/Path.h"
27 #include "llvm/Support/SourceMgr.h"
28 #include "llvm/Support/raw_ostream.h"
31 // Given a special op, return the address skip amount (in units of
32 // DWARF2_LINE_MIN_INSN_LENGTH.
33 #define SPECIAL_ADDR(op) (((op) - DWARF2_LINE_OPCODE_BASE)/DWARF2_LINE_RANGE)
35 // The maximum address skip amount that can be encoded with a special op.
36 #define MAX_SPECIAL_ADDR_DELTA SPECIAL_ADDR(255)
38 // First special line opcode - leave room for the standard opcodes.
39 // Note: If you want to change this, you'll have to update the
40 // "standard_opcode_lengths" table that is emitted in DwarfFileTable::Emit().
41 #define DWARF2_LINE_OPCODE_BASE 13
43 // Minimum line offset in a special line info. opcode. This value
44 // was chosen to give a reasonable range of values.
45 #define DWARF2_LINE_BASE -5
47 // Range of line offsets in a special line info. opcode.
48 #define DWARF2_LINE_RANGE 14
50 // Define the architecture-dependent minimum instruction length (in bytes).
51 // This value should be rather too small than too big.
52 #define DWARF2_LINE_MIN_INSN_LENGTH 1
54 // Note: when DWARF2_LINE_MIN_INSN_LENGTH == 1 which is the current setting,
55 // this routine is a nop and will be optimized away.
56 static inline uint64_t ScaleAddrDelta(uint64_t AddrDelta) {
57 if (DWARF2_LINE_MIN_INSN_LENGTH == 1)
59 if (AddrDelta % DWARF2_LINE_MIN_INSN_LENGTH != 0) {
60 // TODO: report this error, but really only once.
63 return AddrDelta / DWARF2_LINE_MIN_INSN_LENGTH;
67 // This is called when an instruction is assembled into the specified section
68 // and if there is information from the last .loc directive that has yet to have
69 // a line entry made for it is made.
71 void MCLineEntry::Make(MCStreamer *MCOS, const MCSection *Section) {
72 if (!MCOS->getContext().getDwarfLocSeen())
75 // Create a symbol at in the current section for use in the line entry.
76 MCSymbol *LineSym = MCOS->getContext().CreateTempSymbol();
77 // Set the value of the symbol to use for the MCLineEntry.
78 MCOS->EmitLabel(LineSym);
80 // Get the current .loc info saved in the context.
81 const MCDwarfLoc &DwarfLoc = MCOS->getContext().getCurrentDwarfLoc();
83 // Create a (local) line entry with the symbol and the current .loc info.
84 MCLineEntry LineEntry(LineSym, DwarfLoc);
86 // clear DwarfLocSeen saying the current .loc info is now used.
87 MCOS->getContext().ClearDwarfLocSeen();
89 // Get the MCLineSection for this section, if one does not exist for this
91 const DenseMap<const MCSection *, MCLineSection *> &MCLineSections =
92 MCOS->getContext().getMCLineSections();
93 MCLineSection *LineSection = MCLineSections.lookup(Section);
95 // Create a new MCLineSection. This will be deleted after the dwarf line
96 // table is created using it by iterating through the MCLineSections
98 LineSection = new MCLineSection;
99 // Save a pointer to the new LineSection into the MCLineSections DenseMap.
100 MCOS->getContext().addMCLineSection(Section, LineSection);
103 // Add the line entry to this section's entries.
104 LineSection->addLineEntry(LineEntry);
108 // This helper routine returns an expression of End - Start + IntVal .
110 static inline const MCExpr *MakeStartMinusEndExpr(const MCStreamer &MCOS,
111 const MCSymbol &Start,
114 MCSymbolRefExpr::VariantKind Variant = MCSymbolRefExpr::VK_None;
116 MCSymbolRefExpr::Create(&End, Variant, MCOS.getContext());
118 MCSymbolRefExpr::Create(&Start, Variant, MCOS.getContext());
120 MCBinaryExpr::Create(MCBinaryExpr::Sub, Res, RHS, MCOS.getContext());
122 MCConstantExpr::Create(IntVal, MCOS.getContext());
124 MCBinaryExpr::Create(MCBinaryExpr::Sub, Res1, Res2, MCOS.getContext());
129 // This emits the Dwarf line table for the specified section from the entries
130 // in the LineSection.
132 static inline void EmitDwarfLineTable(MCStreamer *MCOS,
133 const MCSection *Section,
134 const MCLineSection *LineSection) {
135 unsigned FileNum = 1;
136 unsigned LastLine = 1;
138 unsigned Flags = DWARF2_LINE_DEFAULT_IS_STMT ? DWARF2_FLAG_IS_STMT : 0;
140 MCSymbol *LastLabel = NULL;
142 // Loop through each MCLineEntry and encode the dwarf line number table.
143 for (MCLineSection::const_iterator
144 it = LineSection->getMCLineEntries()->begin(),
145 ie = LineSection->getMCLineEntries()->end(); it != ie; ++it) {
147 if (FileNum != it->getFileNum()) {
148 FileNum = it->getFileNum();
149 MCOS->EmitIntValue(dwarf::DW_LNS_set_file, 1);
150 MCOS->EmitULEB128IntValue(FileNum);
152 if (Column != it->getColumn()) {
153 Column = it->getColumn();
154 MCOS->EmitIntValue(dwarf::DW_LNS_set_column, 1);
155 MCOS->EmitULEB128IntValue(Column);
157 if (Isa != it->getIsa()) {
159 MCOS->EmitIntValue(dwarf::DW_LNS_set_isa, 1);
160 MCOS->EmitULEB128IntValue(Isa);
162 if ((it->getFlags() ^ Flags) & DWARF2_FLAG_IS_STMT) {
163 Flags = it->getFlags();
164 MCOS->EmitIntValue(dwarf::DW_LNS_negate_stmt, 1);
166 if (it->getFlags() & DWARF2_FLAG_BASIC_BLOCK)
167 MCOS->EmitIntValue(dwarf::DW_LNS_set_basic_block, 1);
168 if (it->getFlags() & DWARF2_FLAG_PROLOGUE_END)
169 MCOS->EmitIntValue(dwarf::DW_LNS_set_prologue_end, 1);
170 if (it->getFlags() & DWARF2_FLAG_EPILOGUE_BEGIN)
171 MCOS->EmitIntValue(dwarf::DW_LNS_set_epilogue_begin, 1);
173 int64_t LineDelta = static_cast<int64_t>(it->getLine()) - LastLine;
174 MCSymbol *Label = it->getLabel();
176 // At this point we want to emit/create the sequence to encode the delta in
177 // line numbers and the increment of the address from the previous Label
178 // and the current Label.
179 const MCAsmInfo &asmInfo = MCOS->getContext().getAsmInfo();
180 MCOS->EmitDwarfAdvanceLineAddr(LineDelta, LastLabel, Label,
181 asmInfo.getPointerSize());
183 LastLine = it->getLine();
187 // Emit a DW_LNE_end_sequence for the end of the section.
188 // Using the pointer Section create a temporary label at the end of the
189 // section and use that and the LastLabel to compute the address delta
190 // and use INT64_MAX as the line delta which is the signal that this is
191 // actually a DW_LNE_end_sequence.
193 // Switch to the section to be able to create a symbol at its end.
194 MCOS->SwitchSection(Section);
196 MCContext &context = MCOS->getContext();
197 // Create a symbol at the end of the section.
198 MCSymbol *SectionEnd = context.CreateTempSymbol();
199 // Set the value of the symbol, as we are at the end of the section.
200 MCOS->EmitLabel(SectionEnd);
202 // Switch back the dwarf line section.
203 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfLineSection());
205 const MCAsmInfo &asmInfo = MCOS->getContext().getAsmInfo();
206 MCOS->EmitDwarfAdvanceLineAddr(INT64_MAX, LastLabel, SectionEnd,
207 asmInfo.getPointerSize());
211 // This emits the Dwarf file and the line tables.
213 const MCSymbol *MCDwarfFileTable::Emit(MCStreamer *MCOS) {
214 MCContext &context = MCOS->getContext();
215 // Switch to the section where the table will be emitted into.
216 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfLineSection());
218 // Create a symbol at the beginning of this section.
219 MCSymbol *LineStartSym = context.CreateTempSymbol();
220 // Set the value of the symbol, as we are at the start of the section.
221 MCOS->EmitLabel(LineStartSym);
223 // Create a symbol for the end of the section (to be set when we get there).
224 MCSymbol *LineEndSym = context.CreateTempSymbol();
226 // The first 4 bytes is the total length of the information for this
227 // compilation unit (not including these 4 bytes for the length).
228 MCOS->EmitAbsValue(MakeStartMinusEndExpr(*MCOS, *LineStartSym, *LineEndSym,4),
231 // Next 2 bytes is the Version, which is Dwarf 2.
232 MCOS->EmitIntValue(2, 2);
234 // Create a symbol for the end of the prologue (to be set when we get there).
235 MCSymbol *ProEndSym = context.CreateTempSymbol(); // Lprologue_end
237 // Length of the prologue, is the next 4 bytes. Which is the start of the
238 // section to the end of the prologue. Not including the 4 bytes for the
239 // total length, the 2 bytes for the version, and these 4 bytes for the
240 // length of the prologue.
241 MCOS->EmitAbsValue(MakeStartMinusEndExpr(*MCOS, *LineStartSym, *ProEndSym,
245 // Parameters of the state machine, are next.
246 MCOS->EmitIntValue(DWARF2_LINE_MIN_INSN_LENGTH, 1);
247 MCOS->EmitIntValue(DWARF2_LINE_DEFAULT_IS_STMT, 1);
248 MCOS->EmitIntValue(DWARF2_LINE_BASE, 1);
249 MCOS->EmitIntValue(DWARF2_LINE_RANGE, 1);
250 MCOS->EmitIntValue(DWARF2_LINE_OPCODE_BASE, 1);
252 // Standard opcode lengths
253 MCOS->EmitIntValue(0, 1); // length of DW_LNS_copy
254 MCOS->EmitIntValue(1, 1); // length of DW_LNS_advance_pc
255 MCOS->EmitIntValue(1, 1); // length of DW_LNS_advance_line
256 MCOS->EmitIntValue(1, 1); // length of DW_LNS_set_file
257 MCOS->EmitIntValue(1, 1); // length of DW_LNS_set_column
258 MCOS->EmitIntValue(0, 1); // length of DW_LNS_negate_stmt
259 MCOS->EmitIntValue(0, 1); // length of DW_LNS_set_basic_block
260 MCOS->EmitIntValue(0, 1); // length of DW_LNS_const_add_pc
261 MCOS->EmitIntValue(1, 1); // length of DW_LNS_fixed_advance_pc
262 MCOS->EmitIntValue(0, 1); // length of DW_LNS_set_prologue_end
263 MCOS->EmitIntValue(0, 1); // length of DW_LNS_set_epilogue_begin
264 MCOS->EmitIntValue(1, 1); // DW_LNS_set_isa
266 // Put out the directory and file tables.
268 // First the directory table.
269 const std::vector<StringRef> &MCDwarfDirs =
270 context.getMCDwarfDirs();
271 for (unsigned i = 0; i < MCDwarfDirs.size(); i++) {
272 MCOS->EmitBytes(MCDwarfDirs[i], 0); // the DirectoryName
273 MCOS->EmitBytes(StringRef("\0", 1), 0); // the null term. of the string
275 MCOS->EmitIntValue(0, 1); // Terminate the directory list
277 // Second the file table.
278 const std::vector<MCDwarfFile *> &MCDwarfFiles =
279 MCOS->getContext().getMCDwarfFiles();
280 for (unsigned i = 1; i < MCDwarfFiles.size(); i++) {
281 MCOS->EmitBytes(MCDwarfFiles[i]->getName(), 0); // FileName
282 MCOS->EmitBytes(StringRef("\0", 1), 0); // the null term. of the string
284 MCOS->EmitULEB128IntValue(MCDwarfFiles[i]->getDirIndex());
285 MCOS->EmitIntValue(0, 1); // last modification timestamp (always 0)
286 MCOS->EmitIntValue(0, 1); // filesize (always 0)
288 MCOS->EmitIntValue(0, 1); // Terminate the file list
290 // This is the end of the prologue, so set the value of the symbol at the
291 // end of the prologue (that was used in a previous expression).
292 MCOS->EmitLabel(ProEndSym);
294 // Put out the line tables.
295 const DenseMap<const MCSection *, MCLineSection *> &MCLineSections =
296 MCOS->getContext().getMCLineSections();
297 const std::vector<const MCSection *> &MCLineSectionOrder =
298 MCOS->getContext().getMCLineSectionOrder();
299 for (std::vector<const MCSection*>::const_iterator it =
300 MCLineSectionOrder.begin(), ie = MCLineSectionOrder.end(); it != ie;
302 const MCSection *Sec = *it;
303 const MCLineSection *Line = MCLineSections.lookup(Sec);
304 EmitDwarfLineTable(MCOS, Sec, Line);
306 // Now delete the MCLineSections that were created in MCLineEntry::Make()
307 // and used to emit the line table.
311 if (MCOS->getContext().getAsmInfo().getLinkerRequiresNonEmptyDwarfLines()
312 && MCLineSectionOrder.begin() == MCLineSectionOrder.end()) {
313 // The darwin9 linker has a bug (see PR8715). For for 32-bit architectures
315 // total_length >= prologue_length + 10
316 // We are 4 bytes short, since we have total_length = 51 and
317 // prologue_length = 45
319 // The regular end_sequence should be sufficient.
320 MCDwarfLineAddr::Emit(MCOS, INT64_MAX, 0);
323 // This is the end of the section, so set the value of the symbol at the end
324 // of this section (that was used in a previous expression).
325 MCOS->EmitLabel(LineEndSym);
330 /// Utility function to write the encoding to an object writer.
331 void MCDwarfLineAddr::Write(MCObjectWriter *OW, int64_t LineDelta,
332 uint64_t AddrDelta) {
333 SmallString<256> Tmp;
334 raw_svector_ostream OS(Tmp);
335 MCDwarfLineAddr::Encode(LineDelta, AddrDelta, OS);
336 OW->WriteBytes(OS.str());
339 /// Utility function to emit the encoding to a streamer.
340 void MCDwarfLineAddr::Emit(MCStreamer *MCOS, int64_t LineDelta,
341 uint64_t AddrDelta) {
342 SmallString<256> Tmp;
343 raw_svector_ostream OS(Tmp);
344 MCDwarfLineAddr::Encode(LineDelta, AddrDelta, OS);
345 MCOS->EmitBytes(OS.str(), /*AddrSpace=*/0);
348 /// Utility function to encode a Dwarf pair of LineDelta and AddrDeltas.
349 void MCDwarfLineAddr::Encode(int64_t LineDelta, uint64_t AddrDelta,
351 uint64_t Temp, Opcode;
352 bool NeedCopy = false;
354 // Scale the address delta by the minimum instruction length.
355 AddrDelta = ScaleAddrDelta(AddrDelta);
357 // A LineDelta of INT64_MAX is a signal that this is actually a
358 // DW_LNE_end_sequence. We cannot use special opcodes here, since we want the
359 // end_sequence to emit the matrix entry.
360 if (LineDelta == INT64_MAX) {
361 if (AddrDelta == MAX_SPECIAL_ADDR_DELTA)
362 OS << char(dwarf::DW_LNS_const_add_pc);
364 OS << char(dwarf::DW_LNS_advance_pc);
365 encodeULEB128(AddrDelta, OS);
367 OS << char(dwarf::DW_LNS_extended_op);
369 OS << char(dwarf::DW_LNE_end_sequence);
373 // Bias the line delta by the base.
374 Temp = LineDelta - DWARF2_LINE_BASE;
376 // If the line increment is out of range of a special opcode, we must encode
377 // it with DW_LNS_advance_line.
378 if (Temp >= DWARF2_LINE_RANGE) {
379 OS << char(dwarf::DW_LNS_advance_line);
380 encodeSLEB128(LineDelta, OS);
383 Temp = 0 - DWARF2_LINE_BASE;
387 // Use DW_LNS_copy instead of a "line +0, addr +0" special opcode.
388 if (LineDelta == 0 && AddrDelta == 0) {
389 OS << char(dwarf::DW_LNS_copy);
393 // Bias the opcode by the special opcode base.
394 Temp += DWARF2_LINE_OPCODE_BASE;
396 // Avoid overflow when addr_delta is large.
397 if (AddrDelta < 256 + MAX_SPECIAL_ADDR_DELTA) {
398 // Try using a special opcode.
399 Opcode = Temp + AddrDelta * DWARF2_LINE_RANGE;
405 // Try using DW_LNS_const_add_pc followed by special op.
406 Opcode = Temp + (AddrDelta - MAX_SPECIAL_ADDR_DELTA) * DWARF2_LINE_RANGE;
408 OS << char(dwarf::DW_LNS_const_add_pc);
414 // Otherwise use DW_LNS_advance_pc.
415 OS << char(dwarf::DW_LNS_advance_pc);
416 encodeULEB128(AddrDelta, OS);
419 OS << char(dwarf::DW_LNS_copy);
424 void MCDwarfFile::print(raw_ostream &OS) const {
425 OS << '"' << getName() << '"';
428 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
429 void MCDwarfFile::dump() const {
434 // Utility function to write a tuple for .debug_abbrev.
435 static void EmitAbbrev(MCStreamer *MCOS, uint64_t Name, uint64_t Form) {
436 MCOS->EmitULEB128IntValue(Name);
437 MCOS->EmitULEB128IntValue(Form);
440 // When generating dwarf for assembly source files this emits
441 // the data for .debug_abbrev section which contains three DIEs.
442 static void EmitGenDwarfAbbrev(MCStreamer *MCOS) {
443 MCContext &context = MCOS->getContext();
444 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfAbbrevSection());
446 // DW_TAG_compile_unit DIE abbrev (1).
447 MCOS->EmitULEB128IntValue(1);
448 MCOS->EmitULEB128IntValue(dwarf::DW_TAG_compile_unit);
449 MCOS->EmitIntValue(dwarf::DW_CHILDREN_yes, 1);
450 EmitAbbrev(MCOS, dwarf::DW_AT_stmt_list, dwarf::DW_FORM_data4);
451 EmitAbbrev(MCOS, dwarf::DW_AT_low_pc, dwarf::DW_FORM_addr);
452 EmitAbbrev(MCOS, dwarf::DW_AT_high_pc, dwarf::DW_FORM_addr);
453 EmitAbbrev(MCOS, dwarf::DW_AT_name, dwarf::DW_FORM_string);
454 EmitAbbrev(MCOS, dwarf::DW_AT_comp_dir, dwarf::DW_FORM_string);
455 StringRef DwarfDebugFlags = context.getDwarfDebugFlags();
456 if (!DwarfDebugFlags.empty())
457 EmitAbbrev(MCOS, dwarf::DW_AT_APPLE_flags, dwarf::DW_FORM_string);
458 EmitAbbrev(MCOS, dwarf::DW_AT_producer, dwarf::DW_FORM_string);
459 EmitAbbrev(MCOS, dwarf::DW_AT_language, dwarf::DW_FORM_data2);
460 EmitAbbrev(MCOS, 0, 0);
462 // DW_TAG_label DIE abbrev (2).
463 MCOS->EmitULEB128IntValue(2);
464 MCOS->EmitULEB128IntValue(dwarf::DW_TAG_label);
465 MCOS->EmitIntValue(dwarf::DW_CHILDREN_yes, 1);
466 EmitAbbrev(MCOS, dwarf::DW_AT_name, dwarf::DW_FORM_string);
467 EmitAbbrev(MCOS, dwarf::DW_AT_decl_file, dwarf::DW_FORM_data4);
468 EmitAbbrev(MCOS, dwarf::DW_AT_decl_line, dwarf::DW_FORM_data4);
469 EmitAbbrev(MCOS, dwarf::DW_AT_low_pc, dwarf::DW_FORM_addr);
470 EmitAbbrev(MCOS, dwarf::DW_AT_prototyped, dwarf::DW_FORM_flag);
471 EmitAbbrev(MCOS, 0, 0);
473 // DW_TAG_unspecified_parameters DIE abbrev (3).
474 MCOS->EmitULEB128IntValue(3);
475 MCOS->EmitULEB128IntValue(dwarf::DW_TAG_unspecified_parameters);
476 MCOS->EmitIntValue(dwarf::DW_CHILDREN_no, 1);
477 EmitAbbrev(MCOS, 0, 0);
479 // Terminate the abbreviations for this compilation unit.
480 MCOS->EmitIntValue(0, 1);
483 // When generating dwarf for assembly source files this emits the data for
484 // .debug_aranges section. Which contains a header and a table of pairs of
485 // PointerSize'ed values for the address and size of section(s) with line table
486 // entries (just the default .text in our case) and a terminating pair of zeros.
487 static void EmitGenDwarfAranges(MCStreamer *MCOS,
488 const MCSymbol *InfoSectionSymbol) {
489 MCContext &context = MCOS->getContext();
491 // Create a symbol at the end of the section that we are creating the dwarf
492 // debugging info to use later in here as part of the expression to calculate
493 // the size of the section for the table.
494 MCOS->SwitchSection(context.getGenDwarfSection());
495 MCSymbol *SectionEndSym = context.CreateTempSymbol();
496 MCOS->EmitLabel(SectionEndSym);
497 context.setGenDwarfSectionEndSym(SectionEndSym);
499 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfARangesSection());
501 // This will be the length of the .debug_aranges section, first account for
502 // the size of each item in the header (see below where we emit these items).
503 int Length = 4 + 2 + 4 + 1 + 1;
505 // Figure the padding after the header before the table of address and size
506 // pairs who's values are PointerSize'ed.
507 const MCAsmInfo &asmInfo = context.getAsmInfo();
508 int AddrSize = asmInfo.getPointerSize();
509 int Pad = 2 * AddrSize - (Length & (2 * AddrSize - 1));
510 if (Pad == 2 * AddrSize)
514 // Add the size of the pair of PointerSize'ed values for the address and size
515 // of the one default .text section we have in the table.
516 Length += 2 * AddrSize;
517 // And the pair of terminating zeros.
518 Length += 2 * AddrSize;
521 // Emit the header for this section.
522 // The 4 byte length not including the 4 byte value for the length.
523 MCOS->EmitIntValue(Length - 4, 4);
524 // The 2 byte version, which is 2.
525 MCOS->EmitIntValue(2, 2);
526 // The 4 byte offset to the compile unit in the .debug_info from the start
527 // of the .debug_info.
528 if (InfoSectionSymbol)
529 MCOS->EmitSymbolValue(InfoSectionSymbol, 4);
531 MCOS->EmitIntValue(0, 4);
532 // The 1 byte size of an address.
533 MCOS->EmitIntValue(AddrSize, 1);
534 // The 1 byte size of a segment descriptor, we use a value of zero.
535 MCOS->EmitIntValue(0, 1);
536 // Align the header with the padding if needed, before we put out the table.
537 for(int i = 0; i < Pad; i++)
538 MCOS->EmitIntValue(0, 1);
540 // Now emit the table of pairs of PointerSize'ed values for the section(s)
541 // address and size, in our case just the one default .text section.
542 const MCExpr *Addr = MCSymbolRefExpr::Create(
543 context.getGenDwarfSectionStartSym(), MCSymbolRefExpr::VK_None, context);
544 const MCExpr *Size = MakeStartMinusEndExpr(*MCOS,
545 *context.getGenDwarfSectionStartSym(), *SectionEndSym, 0);
546 MCOS->EmitAbsValue(Addr, AddrSize);
547 MCOS->EmitAbsValue(Size, AddrSize);
549 // And finally the pair of terminating zeros.
550 MCOS->EmitIntValue(0, AddrSize);
551 MCOS->EmitIntValue(0, AddrSize);
554 // When generating dwarf for assembly source files this emits the data for
555 // .debug_info section which contains three parts. The header, the compile_unit
556 // DIE and a list of label DIEs.
557 static void EmitGenDwarfInfo(MCStreamer *MCOS,
558 const MCSymbol *AbbrevSectionSymbol,
559 const MCSymbol *LineSectionSymbol) {
560 MCContext &context = MCOS->getContext();
562 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfInfoSection());
564 // Create a symbol at the start and end of this section used in here for the
565 // expression to calculate the length in the header.
566 MCSymbol *InfoStart = context.CreateTempSymbol();
567 MCOS->EmitLabel(InfoStart);
568 MCSymbol *InfoEnd = context.CreateTempSymbol();
570 // First part: the header.
572 // The 4 byte total length of the information for this compilation unit, not
573 // including these 4 bytes.
574 const MCExpr *Length = MakeStartMinusEndExpr(*MCOS, *InfoStart, *InfoEnd, 4);
575 MCOS->EmitAbsValue(Length, 4);
577 // The 2 byte DWARF version, which is 2.
578 MCOS->EmitIntValue(2, 2);
580 // The 4 byte offset to the debug abbrevs from the start of the .debug_abbrev,
581 // it is at the start of that section so this is zero.
582 if (AbbrevSectionSymbol) {
583 MCOS->EmitSymbolValue(AbbrevSectionSymbol, 4);
585 MCOS->EmitIntValue(0, 4);
588 const MCAsmInfo &asmInfo = context.getAsmInfo();
589 int AddrSize = asmInfo.getPointerSize();
590 // The 1 byte size of an address.
591 MCOS->EmitIntValue(AddrSize, 1);
593 // Second part: the compile_unit DIE.
595 // The DW_TAG_compile_unit DIE abbrev (1).
596 MCOS->EmitULEB128IntValue(1);
598 // DW_AT_stmt_list, a 4 byte offset from the start of the .debug_line section,
599 // which is at the start of that section so this is zero.
600 if (LineSectionSymbol) {
601 MCOS->EmitSymbolValue(LineSectionSymbol, 4);
603 MCOS->EmitIntValue(0, 4);
606 // AT_low_pc, the first address of the default .text section.
607 const MCExpr *Start = MCSymbolRefExpr::Create(
608 context.getGenDwarfSectionStartSym(), MCSymbolRefExpr::VK_None, context);
609 MCOS->EmitAbsValue(Start, AddrSize);
611 // AT_high_pc, the last address of the default .text section.
612 const MCExpr *End = MCSymbolRefExpr::Create(
613 context.getGenDwarfSectionEndSym(), MCSymbolRefExpr::VK_None, context);
614 MCOS->EmitAbsValue(End, AddrSize);
616 // AT_name, the name of the source file. Reconstruct from the first directory
617 // and file table entries.
618 const std::vector<StringRef> &MCDwarfDirs =
619 context.getMCDwarfDirs();
620 if (MCDwarfDirs.size() > 0) {
621 MCOS->EmitBytes(MCDwarfDirs[0], 0);
622 MCOS->EmitBytes("/", 0);
624 const std::vector<MCDwarfFile *> &MCDwarfFiles =
625 MCOS->getContext().getMCDwarfFiles();
626 MCOS->EmitBytes(MCDwarfFiles[1]->getName(), 0);
627 MCOS->EmitIntValue(0, 1); // NULL byte to terminate the string.
629 // AT_comp_dir, the working directory the assembly was done in.
630 MCOS->EmitBytes(context.getCompilationDir(), 0);
631 MCOS->EmitIntValue(0, 1); // NULL byte to terminate the string.
633 // AT_APPLE_flags, the command line arguments of the assembler tool.
634 StringRef DwarfDebugFlags = context.getDwarfDebugFlags();
635 if (!DwarfDebugFlags.empty()){
636 MCOS->EmitBytes(DwarfDebugFlags, 0);
637 MCOS->EmitIntValue(0, 1); // NULL byte to terminate the string.
640 // AT_producer, the version of the assembler tool.
641 MCOS->EmitBytes(StringRef("llvm-mc (based on LLVM "), 0);
642 MCOS->EmitBytes(StringRef(PACKAGE_VERSION), 0);
643 MCOS->EmitBytes(StringRef(")"), 0);
644 MCOS->EmitIntValue(0, 1); // NULL byte to terminate the string.
646 // AT_language, a 4 byte value. We use DW_LANG_Mips_Assembler as the dwarf2
647 // draft has no standard code for assembler.
648 MCOS->EmitIntValue(dwarf::DW_LANG_Mips_Assembler, 2);
650 // Third part: the list of label DIEs.
652 // Loop on saved info for dwarf labels and create the DIEs for them.
653 const std::vector<const MCGenDwarfLabelEntry *> &Entries =
654 MCOS->getContext().getMCGenDwarfLabelEntries();
655 for (std::vector<const MCGenDwarfLabelEntry *>::const_iterator it =
656 Entries.begin(), ie = Entries.end(); it != ie;
658 const MCGenDwarfLabelEntry *Entry = *it;
660 // The DW_TAG_label DIE abbrev (2).
661 MCOS->EmitULEB128IntValue(2);
663 // AT_name, of the label without any leading underbar.
664 MCOS->EmitBytes(Entry->getName(), 0);
665 MCOS->EmitIntValue(0, 1); // NULL byte to terminate the string.
667 // AT_decl_file, index into the file table.
668 MCOS->EmitIntValue(Entry->getFileNumber(), 4);
670 // AT_decl_line, source line number.
671 MCOS->EmitIntValue(Entry->getLineNumber(), 4);
673 // AT_low_pc, start address of the label.
674 const MCExpr *AT_low_pc = MCSymbolRefExpr::Create(Entry->getLabel(),
675 MCSymbolRefExpr::VK_None, context);
676 MCOS->EmitAbsValue(AT_low_pc, AddrSize);
678 // DW_AT_prototyped, a one byte flag value of 0 saying we have no prototype.
679 MCOS->EmitIntValue(0, 1);
681 // The DW_TAG_unspecified_parameters DIE abbrev (3).
682 MCOS->EmitULEB128IntValue(3);
684 // Add the NULL DIE terminating the DW_TAG_unspecified_parameters DIE's.
685 MCOS->EmitIntValue(0, 1);
687 // Deallocate the MCGenDwarfLabelEntry classes that saved away the info
688 // for the dwarf labels.
689 for (std::vector<const MCGenDwarfLabelEntry *>::const_iterator it =
690 Entries.begin(), ie = Entries.end(); it != ie;
692 const MCGenDwarfLabelEntry *Entry = *it;
696 // Add the NULL DIE terminating the Compile Unit DIE's.
697 MCOS->EmitIntValue(0, 1);
699 // Now set the value of the symbol at the end of the info section.
700 MCOS->EmitLabel(InfoEnd);
704 // When generating dwarf for assembly source files this emits the Dwarf
707 void MCGenDwarfInfo::Emit(MCStreamer *MCOS, const MCSymbol *LineSectionSymbol) {
708 // Create the dwarf sections in this order (.debug_line already created).
709 MCContext &context = MCOS->getContext();
710 const MCAsmInfo &AsmInfo = context.getAsmInfo();
711 bool CreateDwarfSectionSymbols =
712 AsmInfo.doesDwarfUseRelocationsAcrossSections();
713 if (!CreateDwarfSectionSymbols)
714 LineSectionSymbol = NULL;
715 MCSymbol *AbbrevSectionSymbol = NULL;
716 MCSymbol *InfoSectionSymbol = NULL;
717 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfInfoSection());
718 if (CreateDwarfSectionSymbols) {
719 InfoSectionSymbol = context.CreateTempSymbol();
720 MCOS->EmitLabel(InfoSectionSymbol);
722 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfAbbrevSection());
723 if (CreateDwarfSectionSymbols) {
724 AbbrevSectionSymbol = context.CreateTempSymbol();
725 MCOS->EmitLabel(AbbrevSectionSymbol);
727 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfARangesSection());
729 // If there are no line table entries then do not emit any section contents.
730 if (context.getMCLineSections().empty())
733 // Output the data for .debug_aranges section.
734 EmitGenDwarfAranges(MCOS, InfoSectionSymbol);
736 // Output the data for .debug_abbrev section.
737 EmitGenDwarfAbbrev(MCOS);
739 // Output the data for .debug_info section.
740 EmitGenDwarfInfo(MCOS, AbbrevSectionSymbol, LineSectionSymbol);
744 // When generating dwarf for assembly source files this is called when symbol
745 // for a label is created. If this symbol is not a temporary and is in the
746 // section that dwarf is being generated for, save the needed info to create
749 void MCGenDwarfLabelEntry::Make(MCSymbol *Symbol, MCStreamer *MCOS,
750 SourceMgr &SrcMgr, SMLoc &Loc) {
751 // We won't create dwarf labels for temporary symbols or symbols not in
753 if (Symbol->isTemporary())
755 MCContext &context = MCOS->getContext();
756 if (context.getGenDwarfSection() != MCOS->getCurrentSection())
759 // The dwarf label's name does not have the symbol name's leading
761 StringRef Name = Symbol->getName();
762 if (Name.startswith("_"))
763 Name = Name.substr(1, Name.size()-1);
765 // Get the dwarf file number to be used for the dwarf label.
766 unsigned FileNumber = context.getGenDwarfFileNumber();
768 // Finding the line number is the expensive part which is why we just don't
769 // pass it in as for some symbols we won't create a dwarf label.
770 int CurBuffer = SrcMgr.FindBufferContainingLoc(Loc);
771 unsigned LineNumber = SrcMgr.FindLineNumber(Loc, CurBuffer);
773 // We create a temporary symbol for use for the AT_high_pc and AT_low_pc
774 // values so that they don't have things like an ARM thumb bit from the
775 // original symbol. So when used they won't get a low bit set after
777 MCSymbol *Label = context.CreateTempSymbol();
778 MCOS->EmitLabel(Label);
780 // Create and entry for the info and add it to the other entries.
781 MCGenDwarfLabelEntry *Entry =
782 new MCGenDwarfLabelEntry(Name, FileNumber, LineNumber, Label);
783 MCOS->getContext().addMCGenDwarfLabelEntry(Entry);
786 static int getDataAlignmentFactor(MCStreamer &streamer) {
787 MCContext &context = streamer.getContext();
788 const MCAsmInfo &asmInfo = context.getAsmInfo();
789 int size = asmInfo.getPointerSize();
790 if (asmInfo.isStackGrowthDirectionUp())
796 static unsigned getSizeForEncoding(MCStreamer &streamer,
797 unsigned symbolEncoding) {
798 MCContext &context = streamer.getContext();
799 unsigned format = symbolEncoding & 0x0f;
801 default: llvm_unreachable("Unknown Encoding");
802 case dwarf::DW_EH_PE_absptr:
803 case dwarf::DW_EH_PE_signed:
804 return context.getAsmInfo().getPointerSize();
805 case dwarf::DW_EH_PE_udata2:
806 case dwarf::DW_EH_PE_sdata2:
808 case dwarf::DW_EH_PE_udata4:
809 case dwarf::DW_EH_PE_sdata4:
811 case dwarf::DW_EH_PE_udata8:
812 case dwarf::DW_EH_PE_sdata8:
817 static void EmitSymbol(MCStreamer &streamer, const MCSymbol &symbol,
818 unsigned symbolEncoding, const char *comment = 0) {
819 MCContext &context = streamer.getContext();
820 const MCAsmInfo &asmInfo = context.getAsmInfo();
821 const MCExpr *v = asmInfo.getExprForFDESymbol(&symbol,
824 unsigned size = getSizeForEncoding(streamer, symbolEncoding);
825 if (streamer.isVerboseAsm() && comment) streamer.AddComment(comment);
826 streamer.EmitAbsValue(v, size);
829 static void EmitPersonality(MCStreamer &streamer, const MCSymbol &symbol,
830 unsigned symbolEncoding) {
831 MCContext &context = streamer.getContext();
832 const MCAsmInfo &asmInfo = context.getAsmInfo();
833 const MCExpr *v = asmInfo.getExprForPersonalitySymbol(&symbol,
836 unsigned size = getSizeForEncoding(streamer, symbolEncoding);
837 streamer.EmitValue(v, size);
840 static const MachineLocation TranslateMachineLocation(
841 const MCRegisterInfo &MRI,
842 const MachineLocation &Loc) {
843 unsigned Reg = Loc.getReg() == MachineLocation::VirtualFP ?
844 MachineLocation::VirtualFP :
845 unsigned(MRI.getDwarfRegNum(Loc.getReg(), true));
846 const MachineLocation &NewLoc = Loc.isReg() ?
847 MachineLocation(Reg) : MachineLocation(Reg, Loc.getOffset());
852 class FrameEmitterImpl {
857 const MCSymbol *SectionStart;
859 FrameEmitterImpl(bool usingCFI, bool isEH)
860 : CFAOffset(0), CIENum(0), UsingCFI(usingCFI), IsEH(isEH),
863 void setSectionStart(const MCSymbol *Label) { SectionStart = Label; }
865 /// EmitCompactUnwind - Emit the unwind information in a compact way. If
866 /// we're successful, return 'true'. Otherwise, return 'false' and it will
867 /// emit the normal CIE and FDE.
868 bool EmitCompactUnwind(MCStreamer &streamer,
869 const MCDwarfFrameInfo &frame);
871 const MCSymbol &EmitCIE(MCStreamer &streamer,
872 const MCSymbol *personality,
873 unsigned personalityEncoding,
874 const MCSymbol *lsda,
876 unsigned lsdaEncoding);
877 MCSymbol *EmitFDE(MCStreamer &streamer,
878 const MCSymbol &cieStart,
879 const MCDwarfFrameInfo &frame);
880 void EmitCFIInstructions(MCStreamer &streamer,
881 const std::vector<MCCFIInstruction> &Instrs,
882 MCSymbol *BaseLabel);
883 void EmitCFIInstruction(MCStreamer &Streamer,
884 const MCCFIInstruction &Instr);
887 } // end anonymous namespace
889 static void EmitEncodingByte(MCStreamer &Streamer, unsigned Encoding,
891 if (Streamer.isVerboseAsm()) {
894 default: EncStr = "<unknown encoding>"; break;
895 case dwarf::DW_EH_PE_absptr: EncStr = "absptr"; break;
896 case dwarf::DW_EH_PE_omit: EncStr = "omit"; break;
897 case dwarf::DW_EH_PE_pcrel: EncStr = "pcrel"; break;
898 case dwarf::DW_EH_PE_udata4: EncStr = "udata4"; break;
899 case dwarf::DW_EH_PE_udata8: EncStr = "udata8"; break;
900 case dwarf::DW_EH_PE_sdata4: EncStr = "sdata4"; break;
901 case dwarf::DW_EH_PE_sdata8: EncStr = "sdata8"; break;
902 case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata4:
903 EncStr = "pcrel udata4";
905 case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4:
906 EncStr = "pcrel sdata4";
908 case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata8:
909 EncStr = "pcrel udata8";
911 case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata8:
912 EncStr = "screl sdata8";
914 case dwarf::DW_EH_PE_indirect |dwarf::DW_EH_PE_pcrel|dwarf::DW_EH_PE_udata4:
915 EncStr = "indirect pcrel udata4";
917 case dwarf::DW_EH_PE_indirect |dwarf::DW_EH_PE_pcrel|dwarf::DW_EH_PE_sdata4:
918 EncStr = "indirect pcrel sdata4";
920 case dwarf::DW_EH_PE_indirect |dwarf::DW_EH_PE_pcrel|dwarf::DW_EH_PE_udata8:
921 EncStr = "indirect pcrel udata8";
923 case dwarf::DW_EH_PE_indirect |dwarf::DW_EH_PE_pcrel|dwarf::DW_EH_PE_sdata8:
924 EncStr = "indirect pcrel sdata8";
928 Streamer.AddComment(Twine(Prefix) + " = " + EncStr);
931 Streamer.EmitIntValue(Encoding, 1);
934 void FrameEmitterImpl::EmitCFIInstruction(MCStreamer &Streamer,
935 const MCCFIInstruction &Instr) {
936 int dataAlignmentFactor = getDataAlignmentFactor(Streamer);
937 bool VerboseAsm = Streamer.isVerboseAsm();
939 switch (Instr.getOperation()) {
940 case MCCFIInstruction::OpRegister: {
941 unsigned Reg1 = Instr.getRegister();
942 unsigned Reg2 = Instr.getRegister2();
944 Streamer.AddComment("DW_CFA_register");
945 Streamer.AddComment(Twine("Reg1 ") + Twine(Reg1));
946 Streamer.AddComment(Twine("Reg2 ") + Twine(Reg2));
948 Streamer.EmitIntValue(dwarf::DW_CFA_register, 1);
949 Streamer.EmitULEB128IntValue(Reg1);
950 Streamer.EmitULEB128IntValue(Reg2);
953 case MCCFIInstruction::OpUndefined: {
954 unsigned Reg = Instr.getRegister();
956 Streamer.AddComment("DW_CFA_undefined");
957 Streamer.AddComment(Twine("Reg ") + Twine(Reg));
959 Streamer.EmitIntValue(dwarf::DW_CFA_undefined, 1);
960 Streamer.EmitULEB128IntValue(Reg);
963 case MCCFIInstruction::OpAdjustCfaOffset:
964 case MCCFIInstruction::OpDefCfaOffset: {
965 const bool IsRelative =
966 Instr.getOperation() == MCCFIInstruction::OpAdjustCfaOffset;
969 Streamer.AddComment("DW_CFA_def_cfa_offset");
970 Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa_offset, 1);
973 CFAOffset += Instr.getOffset();
975 CFAOffset = -Instr.getOffset();
978 Streamer.AddComment(Twine("Offset " + Twine(CFAOffset)));
979 Streamer.EmitULEB128IntValue(CFAOffset);
983 case MCCFIInstruction::OpDefCfa: {
985 Streamer.AddComment("DW_CFA_def_cfa");
986 Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa, 1);
989 Streamer.AddComment(Twine("Reg ") + Twine(Instr.getRegister()));
990 Streamer.EmitULEB128IntValue(Instr.getRegister());
992 CFAOffset = -Instr.getOffset();
995 Streamer.AddComment(Twine("Offset " + Twine(CFAOffset)));
996 Streamer.EmitULEB128IntValue(CFAOffset);
1001 case MCCFIInstruction::OpDefCfaRegister: {
1003 Streamer.AddComment("DW_CFA_def_cfa_register");
1004 Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa_register, 1);
1007 Streamer.AddComment(Twine("Reg ") + Twine(Instr.getRegister()));
1008 Streamer.EmitULEB128IntValue(Instr.getRegister());
1013 case MCCFIInstruction::OpOffset:
1014 case MCCFIInstruction::OpRelOffset: {
1015 const bool IsRelative =
1016 Instr.getOperation() == MCCFIInstruction::OpRelOffset;
1018 unsigned Reg = Instr.getRegister();
1019 int Offset = Instr.getOffset();
1021 Offset -= CFAOffset;
1022 Offset = Offset / dataAlignmentFactor;
1025 if (VerboseAsm) Streamer.AddComment("DW_CFA_offset_extended_sf");
1026 Streamer.EmitIntValue(dwarf::DW_CFA_offset_extended_sf, 1);
1027 if (VerboseAsm) Streamer.AddComment(Twine("Reg ") + Twine(Reg));
1028 Streamer.EmitULEB128IntValue(Reg);
1029 if (VerboseAsm) Streamer.AddComment(Twine("Offset ") + Twine(Offset));
1030 Streamer.EmitSLEB128IntValue(Offset);
1031 } else if (Reg < 64) {
1032 if (VerboseAsm) Streamer.AddComment(Twine("DW_CFA_offset + Reg(") +
1034 Streamer.EmitIntValue(dwarf::DW_CFA_offset + Reg, 1);
1035 if (VerboseAsm) Streamer.AddComment(Twine("Offset ") + Twine(Offset));
1036 Streamer.EmitULEB128IntValue(Offset);
1038 if (VerboseAsm) Streamer.AddComment("DW_CFA_offset_extended");
1039 Streamer.EmitIntValue(dwarf::DW_CFA_offset_extended, 1);
1040 if (VerboseAsm) Streamer.AddComment(Twine("Reg ") + Twine(Reg));
1041 Streamer.EmitULEB128IntValue(Reg);
1042 if (VerboseAsm) Streamer.AddComment(Twine("Offset ") + Twine(Offset));
1043 Streamer.EmitULEB128IntValue(Offset);
1047 case MCCFIInstruction::OpRememberState:
1048 if (VerboseAsm) Streamer.AddComment("DW_CFA_remember_state");
1049 Streamer.EmitIntValue(dwarf::DW_CFA_remember_state, 1);
1051 case MCCFIInstruction::OpRestoreState:
1052 if (VerboseAsm) Streamer.AddComment("DW_CFA_restore_state");
1053 Streamer.EmitIntValue(dwarf::DW_CFA_restore_state, 1);
1055 case MCCFIInstruction::OpSameValue: {
1056 unsigned Reg = Instr.getRegister();
1057 if (VerboseAsm) Streamer.AddComment("DW_CFA_same_value");
1058 Streamer.EmitIntValue(dwarf::DW_CFA_same_value, 1);
1059 if (VerboseAsm) Streamer.AddComment(Twine("Reg ") + Twine(Reg));
1060 Streamer.EmitULEB128IntValue(Reg);
1063 case MCCFIInstruction::OpRestore: {
1064 unsigned Reg = Instr.getRegister();
1066 Streamer.AddComment("DW_CFA_restore");
1067 Streamer.AddComment(Twine("Reg ") + Twine(Reg));
1069 Streamer.EmitIntValue(dwarf::DW_CFA_restore | Reg, 1);
1072 case MCCFIInstruction::OpEscape:
1073 if (VerboseAsm) Streamer.AddComment("Escape bytes");
1074 Streamer.EmitBytes(Instr.getValues(), 0);
1077 llvm_unreachable("Unhandled case in switch");
1080 /// EmitFrameMoves - Emit frame instructions to describe the layout of the
1082 void FrameEmitterImpl::EmitCFIInstructions(MCStreamer &streamer,
1083 const std::vector<MCCFIInstruction> &Instrs,
1084 MCSymbol *BaseLabel) {
1085 for (unsigned i = 0, N = Instrs.size(); i < N; ++i) {
1086 const MCCFIInstruction &Instr = Instrs[i];
1087 MCSymbol *Label = Instr.getLabel();
1088 // Throw out move if the label is invalid.
1089 if (Label && !Label->isDefined()) continue; // Not emitted, in dead code.
1091 // Advance row if new location.
1092 if (BaseLabel && Label) {
1093 MCSymbol *ThisSym = Label;
1094 if (ThisSym != BaseLabel) {
1095 if (streamer.isVerboseAsm()) streamer.AddComment("DW_CFA_advance_loc4");
1096 streamer.EmitDwarfAdvanceFrameAddr(BaseLabel, ThisSym);
1097 BaseLabel = ThisSym;
1101 EmitCFIInstruction(streamer, Instr);
1105 /// EmitCompactUnwind - Emit the unwind information in a compact way. If we're
1106 /// successful, return 'true'. Otherwise, return 'false' and it will emit the
1107 /// normal CIE and FDE.
1108 bool FrameEmitterImpl::EmitCompactUnwind(MCStreamer &Streamer,
1109 const MCDwarfFrameInfo &Frame) {
1110 MCContext &Context = Streamer.getContext();
1111 const MCObjectFileInfo *MOFI = Context.getObjectFileInfo();
1112 bool VerboseAsm = Streamer.isVerboseAsm();
1114 // range-start range-length compact-unwind-enc personality-func lsda
1115 // _foo LfooEnd-_foo 0x00000023 0 0
1116 // _bar LbarEnd-_bar 0x00000025 __gxx_personality except_tab1
1118 // .section __LD,__compact_unwind,regular,debug
1120 // # compact unwind for _foo
1122 // .set L1,LfooEnd-_foo
1128 // # compact unwind for _bar
1130 // .set L2,LbarEnd-_bar
1133 // .quad __gxx_personality
1134 // .quad except_tab1
1136 uint32_t Encoding = Frame.CompactUnwindEncoding;
1137 if (!Encoding) return false;
1139 // The encoding needs to know we have an LSDA.
1141 Encoding |= 0x40000000;
1143 Streamer.SwitchSection(MOFI->getCompactUnwindSection());
1146 unsigned FDEEncoding = MOFI->getFDEEncoding(UsingCFI);
1147 unsigned Size = getSizeForEncoding(Streamer, FDEEncoding);
1148 if (VerboseAsm) Streamer.AddComment("Range Start");
1149 Streamer.EmitSymbolValue(Frame.Function, Size);
1152 const MCExpr *Range = MakeStartMinusEndExpr(Streamer, *Frame.Begin,
1154 if (VerboseAsm) Streamer.AddComment("Range Length");
1155 Streamer.EmitAbsValue(Range, 4);
1158 Size = getSizeForEncoding(Streamer, dwarf::DW_EH_PE_udata4);
1159 if (VerboseAsm) Streamer.AddComment("Compact Unwind Encoding: 0x" +
1160 Twine::utohexstr(Encoding));
1161 Streamer.EmitIntValue(Encoding, Size);
1164 // Personality Function
1165 Size = getSizeForEncoding(Streamer, dwarf::DW_EH_PE_absptr);
1166 if (VerboseAsm) Streamer.AddComment("Personality Function");
1167 if (Frame.Personality)
1168 Streamer.EmitSymbolValue(Frame.Personality, Size);
1170 Streamer.EmitIntValue(0, Size); // No personality fn
1173 Size = getSizeForEncoding(Streamer, Frame.LsdaEncoding);
1174 if (VerboseAsm) Streamer.AddComment("LSDA");
1176 Streamer.EmitSymbolValue(Frame.Lsda, Size);
1178 Streamer.EmitIntValue(0, Size); // No LSDA
1183 const MCSymbol &FrameEmitterImpl::EmitCIE(MCStreamer &streamer,
1184 const MCSymbol *personality,
1185 unsigned personalityEncoding,
1186 const MCSymbol *lsda,
1188 unsigned lsdaEncoding) {
1189 MCContext &context = streamer.getContext();
1190 const MCRegisterInfo &MRI = context.getRegisterInfo();
1191 const MCObjectFileInfo *MOFI = context.getObjectFileInfo();
1192 bool verboseAsm = streamer.isVerboseAsm();
1194 MCSymbol *sectionStart;
1195 if (MOFI->isFunctionEHFrameSymbolPrivate() || !IsEH)
1196 sectionStart = context.CreateTempSymbol();
1198 sectionStart = context.GetOrCreateSymbol(Twine("EH_frame") + Twine(CIENum));
1200 streamer.EmitLabel(sectionStart);
1203 MCSymbol *sectionEnd = context.CreateTempSymbol();
1206 const MCExpr *Length = MakeStartMinusEndExpr(streamer, *sectionStart,
1208 if (verboseAsm) streamer.AddComment("CIE Length");
1209 streamer.EmitAbsValue(Length, 4);
1212 unsigned CIE_ID = IsEH ? 0 : -1;
1213 if (verboseAsm) streamer.AddComment("CIE ID Tag");
1214 streamer.EmitIntValue(CIE_ID, 4);
1217 if (verboseAsm) streamer.AddComment("DW_CIE_VERSION");
1218 streamer.EmitIntValue(dwarf::DW_CIE_VERSION, 1);
1220 // Augmentation String
1221 SmallString<8> Augmentation;
1223 if (verboseAsm) streamer.AddComment("CIE Augmentation");
1224 Augmentation += "z";
1226 Augmentation += "P";
1228 Augmentation += "L";
1229 Augmentation += "R";
1231 Augmentation += "S";
1232 streamer.EmitBytes(Augmentation.str(), 0);
1234 streamer.EmitIntValue(0, 1);
1236 // Code Alignment Factor
1237 if (verboseAsm) streamer.AddComment("CIE Code Alignment Factor");
1238 streamer.EmitULEB128IntValue(1);
1240 // Data Alignment Factor
1241 if (verboseAsm) streamer.AddComment("CIE Data Alignment Factor");
1242 streamer.EmitSLEB128IntValue(getDataAlignmentFactor(streamer));
1244 // Return Address Register
1245 if (verboseAsm) streamer.AddComment("CIE Return Address Column");
1246 streamer.EmitULEB128IntValue(MRI.getDwarfRegNum(MRI.getRARegister(), true));
1248 // Augmentation Data Length (optional)
1250 unsigned augmentationLength = 0;
1253 // Personality Encoding
1254 augmentationLength += 1;
1256 augmentationLength += getSizeForEncoding(streamer, personalityEncoding);
1259 augmentationLength += 1;
1260 // Encoding of the FDE pointers
1261 augmentationLength += 1;
1263 if (verboseAsm) streamer.AddComment("Augmentation Size");
1264 streamer.EmitULEB128IntValue(augmentationLength);
1266 // Augmentation Data (optional)
1268 // Personality Encoding
1269 EmitEncodingByte(streamer, personalityEncoding,
1270 "Personality Encoding");
1272 if (verboseAsm) streamer.AddComment("Personality");
1273 EmitPersonality(streamer, *personality, personalityEncoding);
1277 EmitEncodingByte(streamer, lsdaEncoding, "LSDA Encoding");
1279 // Encoding of the FDE pointers
1280 EmitEncodingByte(streamer, MOFI->getFDEEncoding(UsingCFI),
1284 // Initial Instructions
1286 const MCAsmInfo &MAI = context.getAsmInfo();
1287 const std::vector<MachineMove> &Moves = MAI.getInitialFrameState();
1288 std::vector<MCCFIInstruction> Instructions;
1290 for (int i = 0, n = Moves.size(); i != n; ++i) {
1291 MCSymbol *Label = Moves[i].getLabel();
1292 const MachineLocation &Dst =
1293 TranslateMachineLocation(MRI, Moves[i].getDestination());
1294 const MachineLocation &Src =
1295 TranslateMachineLocation(MRI, Moves[i].getSource());
1298 assert(Dst.getReg() == MachineLocation::VirtualFP);
1299 assert(!Src.isReg());
1300 MCCFIInstruction Inst =
1301 MCCFIInstruction::createDefCfa(Label, Src.getReg(), -Src.getOffset());
1302 Instructions.push_back(Inst);
1304 assert(Src.isReg());
1305 unsigned Reg = Src.getReg();
1306 int Offset = Dst.getOffset();
1307 MCCFIInstruction Inst =
1308 MCCFIInstruction::createOffset(Label, Reg, Offset);
1309 Instructions.push_back(Inst);
1313 EmitCFIInstructions(streamer, Instructions, NULL);
1316 streamer.EmitValueToAlignment(IsEH
1317 ? 4 : context.getAsmInfo().getPointerSize());
1319 streamer.EmitLabel(sectionEnd);
1320 return *sectionStart;
1323 MCSymbol *FrameEmitterImpl::EmitFDE(MCStreamer &streamer,
1324 const MCSymbol &cieStart,
1325 const MCDwarfFrameInfo &frame) {
1326 MCContext &context = streamer.getContext();
1327 MCSymbol *fdeStart = context.CreateTempSymbol();
1328 MCSymbol *fdeEnd = context.CreateTempSymbol();
1329 const MCObjectFileInfo *MOFI = context.getObjectFileInfo();
1330 bool verboseAsm = streamer.isVerboseAsm();
1332 if (IsEH && frame.Function && !MOFI->isFunctionEHFrameSymbolPrivate()) {
1334 context.GetOrCreateSymbol(frame.Function->getName() + Twine(".eh"));
1335 streamer.EmitEHSymAttributes(frame.Function, EHSym);
1336 streamer.EmitLabel(EHSym);
1340 const MCExpr *Length = MakeStartMinusEndExpr(streamer, *fdeStart, *fdeEnd, 0);
1341 if (verboseAsm) streamer.AddComment("FDE Length");
1342 streamer.EmitAbsValue(Length, 4);
1344 streamer.EmitLabel(fdeStart);
1347 const MCAsmInfo &asmInfo = context.getAsmInfo();
1349 const MCExpr *offset = MakeStartMinusEndExpr(streamer, cieStart, *fdeStart,
1351 if (verboseAsm) streamer.AddComment("FDE CIE Offset");
1352 streamer.EmitAbsValue(offset, 4);
1353 } else if (!asmInfo.doesDwarfUseRelocationsAcrossSections()) {
1354 const MCExpr *offset = MakeStartMinusEndExpr(streamer, *SectionStart,
1356 streamer.EmitAbsValue(offset, 4);
1358 streamer.EmitSymbolValue(&cieStart, 4);
1362 unsigned PCEncoding = IsEH ? MOFI->getFDEEncoding(UsingCFI)
1363 : (unsigned)dwarf::DW_EH_PE_absptr;
1364 unsigned PCSize = getSizeForEncoding(streamer, PCEncoding);
1365 EmitSymbol(streamer, *frame.Begin, PCEncoding, "FDE initial location");
1368 const MCExpr *Range = MakeStartMinusEndExpr(streamer, *frame.Begin,
1370 if (verboseAsm) streamer.AddComment("FDE address range");
1371 streamer.EmitAbsValue(Range, PCSize);
1374 // Augmentation Data Length
1375 unsigned augmentationLength = 0;
1378 augmentationLength += getSizeForEncoding(streamer, frame.LsdaEncoding);
1380 if (verboseAsm) streamer.AddComment("Augmentation size");
1381 streamer.EmitULEB128IntValue(augmentationLength);
1383 // Augmentation Data
1385 EmitSymbol(streamer, *frame.Lsda, frame.LsdaEncoding,
1386 "Language Specific Data Area");
1389 // Call Frame Instructions
1391 EmitCFIInstructions(streamer, frame.Instructions, frame.Begin);
1394 streamer.EmitValueToAlignment(PCSize);
1401 static const CIEKey getEmptyKey() { return CIEKey(0, 0, -1, false); }
1402 static const CIEKey getTombstoneKey() { return CIEKey(0, -1, 0, false); }
1404 CIEKey(const MCSymbol* Personality_, unsigned PersonalityEncoding_,
1405 unsigned LsdaEncoding_, bool IsSignalFrame_) :
1406 Personality(Personality_), PersonalityEncoding(PersonalityEncoding_),
1407 LsdaEncoding(LsdaEncoding_), IsSignalFrame(IsSignalFrame_) {
1409 const MCSymbol* Personality;
1410 unsigned PersonalityEncoding;
1411 unsigned LsdaEncoding;
1418 struct DenseMapInfo<CIEKey> {
1419 static CIEKey getEmptyKey() {
1420 return CIEKey::getEmptyKey();
1422 static CIEKey getTombstoneKey() {
1423 return CIEKey::getTombstoneKey();
1425 static unsigned getHashValue(const CIEKey &Key) {
1426 return static_cast<unsigned>(hash_combine(Key.Personality,
1427 Key.PersonalityEncoding,
1429 Key.IsSignalFrame));
1431 static bool isEqual(const CIEKey &LHS,
1432 const CIEKey &RHS) {
1433 return LHS.Personality == RHS.Personality &&
1434 LHS.PersonalityEncoding == RHS.PersonalityEncoding &&
1435 LHS.LsdaEncoding == RHS.LsdaEncoding &&
1436 LHS.IsSignalFrame == RHS.IsSignalFrame;
1441 void MCDwarfFrameEmitter::Emit(MCStreamer &Streamer,
1444 MCContext &Context = Streamer.getContext();
1445 MCObjectFileInfo *MOFI =
1446 const_cast<MCObjectFileInfo*>(Context.getObjectFileInfo());
1447 FrameEmitterImpl Emitter(UsingCFI, IsEH);
1448 ArrayRef<MCDwarfFrameInfo> FrameArray = Streamer.getFrameInfos();
1450 // Emit the compact unwind info if available.
1451 if (IsEH && MOFI->getCompactUnwindSection())
1452 for (unsigned i = 0, n = Streamer.getNumFrameInfos(); i < n; ++i) {
1453 const MCDwarfFrameInfo &Frame = Streamer.getFrameInfo(i);
1454 if (Frame.CompactUnwindEncoding)
1455 Emitter.EmitCompactUnwind(Streamer, Frame);
1458 const MCSection &Section = IsEH ? *MOFI->getEHFrameSection() :
1459 *MOFI->getDwarfFrameSection();
1460 Streamer.SwitchSection(&Section);
1461 MCSymbol *SectionStart = Context.CreateTempSymbol();
1462 Streamer.EmitLabel(SectionStart);
1463 Emitter.setSectionStart(SectionStart);
1465 MCSymbol *FDEEnd = NULL;
1466 DenseMap<CIEKey, const MCSymbol*> CIEStarts;
1468 const MCSymbol *DummyDebugKey = NULL;
1469 for (unsigned i = 0, n = FrameArray.size(); i < n; ++i) {
1470 const MCDwarfFrameInfo &Frame = FrameArray[i];
1471 CIEKey Key(Frame.Personality, Frame.PersonalityEncoding,
1472 Frame.LsdaEncoding, Frame.IsSignalFrame);
1473 const MCSymbol *&CIEStart = IsEH ? CIEStarts[Key] : DummyDebugKey;
1475 CIEStart = &Emitter.EmitCIE(Streamer, Frame.Personality,
1476 Frame.PersonalityEncoding, Frame.Lsda,
1477 Frame.IsSignalFrame,
1478 Frame.LsdaEncoding);
1480 FDEEnd = Emitter.EmitFDE(Streamer, *CIEStart, Frame);
1483 Streamer.EmitLabel(FDEEnd);
1486 Streamer.EmitValueToAlignment(Context.getAsmInfo().getPointerSize());
1488 Streamer.EmitLabel(FDEEnd);
1491 void MCDwarfFrameEmitter::EmitAdvanceLoc(MCStreamer &Streamer,
1492 uint64_t AddrDelta) {
1493 SmallString<256> Tmp;
1494 raw_svector_ostream OS(Tmp);
1495 MCDwarfFrameEmitter::EncodeAdvanceLoc(AddrDelta, OS);
1496 Streamer.EmitBytes(OS.str(), /*AddrSpace=*/0);
1499 void MCDwarfFrameEmitter::EncodeAdvanceLoc(uint64_t AddrDelta,
1501 // FIXME: Assumes the code alignment factor is 1.
1502 if (AddrDelta == 0) {
1503 } else if (isUIntN(6, AddrDelta)) {
1504 uint8_t Opcode = dwarf::DW_CFA_advance_loc | AddrDelta;
1506 } else if (isUInt<8>(AddrDelta)) {
1507 OS << uint8_t(dwarf::DW_CFA_advance_loc1);
1508 OS << uint8_t(AddrDelta);
1509 } else if (isUInt<16>(AddrDelta)) {
1510 // FIXME: check what is the correct behavior on a big endian machine.
1511 OS << uint8_t(dwarf::DW_CFA_advance_loc2);
1512 OS << uint8_t( AddrDelta & 0xff);
1513 OS << uint8_t((AddrDelta >> 8) & 0xff);
1515 // FIXME: check what is the correct behavior on a big endian machine.
1516 assert(isUInt<32>(AddrDelta));
1517 OS << uint8_t(dwarf::DW_CFA_advance_loc4);
1518 OS << uint8_t( AddrDelta & 0xff);
1519 OS << uint8_t((AddrDelta >> 8) & 0xff);
1520 OS << uint8_t((AddrDelta >> 16) & 0xff);
1521 OS << uint8_t((AddrDelta >> 24) & 0xff);