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/ArrayRef.h"
12 #include "llvm/ADT/DenseMap.h"
13 #include "llvm/ADT/Hashing.h"
14 #include "llvm/ADT/Optional.h"
15 #include "llvm/ADT/STLExtras.h"
16 #include "llvm/ADT/SmallString.h"
17 #include "llvm/ADT/SmallVector.h"
18 #include "llvm/ADT/StringRef.h"
19 #include "llvm/ADT/Twine.h"
20 #include "llvm/BinaryFormat/Dwarf.h"
21 #include "llvm/Config/config.h"
22 #include "llvm/MC/MCAsmInfo.h"
23 #include "llvm/MC/MCContext.h"
24 #include "llvm/MC/MCExpr.h"
25 #include "llvm/MC/MCObjectFileInfo.h"
26 #include "llvm/MC/MCObjectStreamer.h"
27 #include "llvm/MC/MCRegisterInfo.h"
28 #include "llvm/MC/MCSection.h"
29 #include "llvm/MC/MCStreamer.h"
30 #include "llvm/MC/MCSymbol.h"
31 #include "llvm/MC/StringTableBuilder.h"
32 #include "llvm/Support/Casting.h"
33 #include "llvm/Support/Endian.h"
34 #include "llvm/Support/EndianStream.h"
35 #include "llvm/Support/ErrorHandling.h"
36 #include "llvm/Support/LEB128.h"
37 #include "llvm/Support/MathExtras.h"
38 #include "llvm/Support/Path.h"
39 #include "llvm/Support/SourceMgr.h"
40 #include "llvm/Support/raw_ostream.h"
49 /// Manage the .debug_line_str section contents, if we use it.
50 class llvm::MCDwarfLineStr {
51 MCSymbol *LineStrLabel = nullptr;
52 StringTableBuilder LineStrings{StringTableBuilder::DWARF};
53 bool UseRelocs = false;
56 /// Construct an instance that can emit .debug_line_str (for use in a normal
58 explicit MCDwarfLineStr(MCContext &Ctx) {
59 UseRelocs = Ctx.getAsmInfo()->doesDwarfUseRelocationsAcrossSections();
62 Ctx.getObjectFileInfo()->getDwarfLineStrSection()->getBeginSymbol();
65 /// Emit a reference to the string.
66 void emitRef(MCStreamer *MCOS, StringRef Path);
68 /// Emit the .debug_line_str section if appropriate.
69 void emitSection(MCStreamer *MCOS);
72 static inline uint64_t ScaleAddrDelta(MCContext &Context, uint64_t AddrDelta) {
73 unsigned MinInsnLength = Context.getAsmInfo()->getMinInstAlignment();
74 if (MinInsnLength == 1)
76 if (AddrDelta % MinInsnLength != 0) {
77 // TODO: report this error, but really only once.
80 return AddrDelta / MinInsnLength;
84 // This is called when an instruction is assembled into the specified section
85 // and if there is information from the last .loc directive that has yet to have
86 // a line entry made for it is made.
88 void MCDwarfLineEntry::Make(MCObjectStreamer *MCOS, MCSection *Section) {
89 if (!MCOS->getContext().getDwarfLocSeen())
92 // Create a symbol at in the current section for use in the line entry.
93 MCSymbol *LineSym = MCOS->getContext().createTempSymbol();
94 // Set the value of the symbol to use for the MCDwarfLineEntry.
95 MCOS->EmitLabel(LineSym);
97 // Get the current .loc info saved in the context.
98 const MCDwarfLoc &DwarfLoc = MCOS->getContext().getCurrentDwarfLoc();
100 // Create a (local) line entry with the symbol and the current .loc info.
101 MCDwarfLineEntry LineEntry(LineSym, DwarfLoc);
103 // clear DwarfLocSeen saying the current .loc info is now used.
104 MCOS->getContext().clearDwarfLocSeen();
106 // Add the line entry to this section's entries.
108 .getMCDwarfLineTable(MCOS->getContext().getDwarfCompileUnitID())
110 .addLineEntry(LineEntry, Section);
114 // This helper routine returns an expression of End - Start + IntVal .
116 static inline const MCExpr *MakeStartMinusEndExpr(const MCStreamer &MCOS,
117 const MCSymbol &Start,
120 MCSymbolRefExpr::VariantKind Variant = MCSymbolRefExpr::VK_None;
122 MCSymbolRefExpr::create(&End, Variant, MCOS.getContext());
124 MCSymbolRefExpr::create(&Start, Variant, MCOS.getContext());
126 MCBinaryExpr::create(MCBinaryExpr::Sub, Res, RHS, MCOS.getContext());
128 MCConstantExpr::create(IntVal, MCOS.getContext());
130 MCBinaryExpr::create(MCBinaryExpr::Sub, Res1, Res2, MCOS.getContext());
135 // This helper routine returns an expression of Start + IntVal .
137 static inline const MCExpr *
138 makeStartPlusIntExpr(MCContext &Ctx, const MCSymbol &Start, int IntVal) {
139 MCSymbolRefExpr::VariantKind Variant = MCSymbolRefExpr::VK_None;
140 const MCExpr *LHS = MCSymbolRefExpr::create(&Start, Variant, Ctx);
141 const MCExpr *RHS = MCConstantExpr::create(IntVal, Ctx);
142 const MCExpr *Res = MCBinaryExpr::create(MCBinaryExpr::Add, LHS, RHS, Ctx);
147 // This emits the Dwarf line table for the specified section from the entries
148 // in the LineSection.
151 EmitDwarfLineTable(MCObjectStreamer *MCOS, MCSection *Section,
152 const MCLineSection::MCDwarfLineEntryCollection &LineEntries) {
153 unsigned FileNum = 1;
154 unsigned LastLine = 1;
156 unsigned Flags = DWARF2_LINE_DEFAULT_IS_STMT ? DWARF2_FLAG_IS_STMT : 0;
158 unsigned Discriminator = 0;
159 MCSymbol *LastLabel = nullptr;
161 // Loop through each MCDwarfLineEntry and encode the dwarf line number table.
162 for (const MCDwarfLineEntry &LineEntry : LineEntries) {
163 int64_t LineDelta = static_cast<int64_t>(LineEntry.getLine()) - LastLine;
165 if (FileNum != LineEntry.getFileNum()) {
166 FileNum = LineEntry.getFileNum();
167 MCOS->EmitIntValue(dwarf::DW_LNS_set_file, 1);
168 MCOS->EmitULEB128IntValue(FileNum);
170 if (Column != LineEntry.getColumn()) {
171 Column = LineEntry.getColumn();
172 MCOS->EmitIntValue(dwarf::DW_LNS_set_column, 1);
173 MCOS->EmitULEB128IntValue(Column);
175 if (Discriminator != LineEntry.getDiscriminator() &&
176 MCOS->getContext().getDwarfVersion() >= 4) {
177 Discriminator = LineEntry.getDiscriminator();
178 unsigned Size = getULEB128Size(Discriminator);
179 MCOS->EmitIntValue(dwarf::DW_LNS_extended_op, 1);
180 MCOS->EmitULEB128IntValue(Size + 1);
181 MCOS->EmitIntValue(dwarf::DW_LNE_set_discriminator, 1);
182 MCOS->EmitULEB128IntValue(Discriminator);
184 if (Isa != LineEntry.getIsa()) {
185 Isa = LineEntry.getIsa();
186 MCOS->EmitIntValue(dwarf::DW_LNS_set_isa, 1);
187 MCOS->EmitULEB128IntValue(Isa);
189 if ((LineEntry.getFlags() ^ Flags) & DWARF2_FLAG_IS_STMT) {
190 Flags = LineEntry.getFlags();
191 MCOS->EmitIntValue(dwarf::DW_LNS_negate_stmt, 1);
193 if (LineEntry.getFlags() & DWARF2_FLAG_BASIC_BLOCK)
194 MCOS->EmitIntValue(dwarf::DW_LNS_set_basic_block, 1);
195 if (LineEntry.getFlags() & DWARF2_FLAG_PROLOGUE_END)
196 MCOS->EmitIntValue(dwarf::DW_LNS_set_prologue_end, 1);
197 if (LineEntry.getFlags() & DWARF2_FLAG_EPILOGUE_BEGIN)
198 MCOS->EmitIntValue(dwarf::DW_LNS_set_epilogue_begin, 1);
200 MCSymbol *Label = LineEntry.getLabel();
202 // At this point we want to emit/create the sequence to encode the delta in
203 // line numbers and the increment of the address from the previous Label
204 // and the current Label.
205 const MCAsmInfo *asmInfo = MCOS->getContext().getAsmInfo();
206 MCOS->EmitDwarfAdvanceLineAddr(LineDelta, LastLabel, Label,
207 asmInfo->getCodePointerSize());
210 LastLine = LineEntry.getLine();
214 // Emit a DW_LNE_end_sequence for the end of the section.
215 // Use the section end label to compute the address delta and use INT64_MAX
216 // as the line delta which is the signal that this is actually a
217 // DW_LNE_end_sequence.
218 MCSymbol *SectionEnd = MCOS->endSection(Section);
220 // Switch back the dwarf line section, in case endSection had to switch the
222 MCContext &Ctx = MCOS->getContext();
223 MCOS->SwitchSection(Ctx.getObjectFileInfo()->getDwarfLineSection());
225 const MCAsmInfo *AsmInfo = Ctx.getAsmInfo();
226 MCOS->EmitDwarfAdvanceLineAddr(INT64_MAX, LastLabel, SectionEnd,
227 AsmInfo->getCodePointerSize());
231 // This emits the Dwarf file and the line tables.
233 void MCDwarfLineTable::Emit(MCObjectStreamer *MCOS,
234 MCDwarfLineTableParams Params) {
235 MCContext &context = MCOS->getContext();
237 auto &LineTables = context.getMCDwarfLineTables();
239 // Bail out early so we don't switch to the debug_line section needlessly and
240 // in doing so create an unnecessary (if empty) section.
241 if (LineTables.empty())
244 // In a v5 non-split line table, put the strings in a separate section.
245 Optional<MCDwarfLineStr> LineStr;
246 if (context.getDwarfVersion() >= 5)
247 LineStr = MCDwarfLineStr(context);
249 // Switch to the section where the table will be emitted into.
250 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfLineSection());
252 // Handle the rest of the Compile Units.
253 for (const auto &CUIDTablePair : LineTables) {
254 CUIDTablePair.second.EmitCU(MCOS, Params, LineStr);
258 LineStr->emitSection(MCOS);
261 void MCDwarfDwoLineTable::Emit(MCStreamer &MCOS, MCDwarfLineTableParams Params,
262 MCSection *Section) const {
263 if (Header.MCDwarfFiles.empty())
265 Optional<MCDwarfLineStr> NoLineStr(None);
266 MCOS.SwitchSection(Section);
267 MCOS.EmitLabel(Header.Emit(&MCOS, Params, None, NoLineStr).second);
270 std::pair<MCSymbol *, MCSymbol *>
271 MCDwarfLineTableHeader::Emit(MCStreamer *MCOS, MCDwarfLineTableParams Params,
272 Optional<MCDwarfLineStr> &LineStr) const {
273 static const char StandardOpcodeLengths[] = {
274 0, // length of DW_LNS_copy
275 1, // length of DW_LNS_advance_pc
276 1, // length of DW_LNS_advance_line
277 1, // length of DW_LNS_set_file
278 1, // length of DW_LNS_set_column
279 0, // length of DW_LNS_negate_stmt
280 0, // length of DW_LNS_set_basic_block
281 0, // length of DW_LNS_const_add_pc
282 1, // length of DW_LNS_fixed_advance_pc
283 0, // length of DW_LNS_set_prologue_end
284 0, // length of DW_LNS_set_epilogue_begin
287 assert(array_lengthof(StandardOpcodeLengths) >=
288 (Params.DWARF2LineOpcodeBase - 1U));
291 makeArrayRef(StandardOpcodeLengths, Params.DWARF2LineOpcodeBase - 1),
295 static const MCExpr *forceExpAbs(MCStreamer &OS, const MCExpr* Expr) {
296 MCContext &Context = OS.getContext();
297 assert(!isa<MCSymbolRefExpr>(Expr));
298 if (Context.getAsmInfo()->hasAggressiveSymbolFolding())
301 MCSymbol *ABS = Context.createTempSymbol();
302 OS.EmitAssignment(ABS, Expr);
303 return MCSymbolRefExpr::create(ABS, Context);
306 static void emitAbsValue(MCStreamer &OS, const MCExpr *Value, unsigned Size) {
307 const MCExpr *ABS = forceExpAbs(OS, Value);
308 OS.EmitValue(ABS, Size);
311 void MCDwarfLineStr::emitSection(MCStreamer *MCOS) {
312 // Switch to the .debug_line_str section.
314 MCOS->getContext().getObjectFileInfo()->getDwarfLineStrSection());
315 // Emit the strings without perturbing the offsets we used.
316 LineStrings.finalizeInOrder();
318 Data.resize(LineStrings.getSize());
319 LineStrings.write((uint8_t *)Data.data());
320 MCOS->EmitBinaryData(Data.str());
323 void MCDwarfLineStr::emitRef(MCStreamer *MCOS, StringRef Path) {
324 int RefSize = 4; // FIXME: Support DWARF-64
325 size_t Offset = LineStrings.add(Path);
327 MCContext &Ctx = MCOS->getContext();
328 MCOS->EmitValue(makeStartPlusIntExpr(Ctx, *LineStrLabel, Offset), RefSize);
330 MCOS->EmitIntValue(Offset, RefSize);
333 void MCDwarfLineTableHeader::emitV2FileDirTables(MCStreamer *MCOS) const {
334 // First the directory table.
335 for (auto &Dir : MCDwarfDirs) {
336 MCOS->EmitBytes(Dir); // The DirectoryName, and...
337 MCOS->EmitBytes(StringRef("\0", 1)); // its null terminator.
339 MCOS->EmitIntValue(0, 1); // Terminate the directory list.
341 // Second the file table.
342 for (unsigned i = 1; i < MCDwarfFiles.size(); i++) {
343 assert(!MCDwarfFiles[i].Name.empty());
344 MCOS->EmitBytes(MCDwarfFiles[i].Name); // FileName and...
345 MCOS->EmitBytes(StringRef("\0", 1)); // its null terminator.
346 MCOS->EmitULEB128IntValue(MCDwarfFiles[i].DirIndex); // Directory number.
347 MCOS->EmitIntValue(0, 1); // Last modification timestamp (always 0).
348 MCOS->EmitIntValue(0, 1); // File size (always 0).
350 MCOS->EmitIntValue(0, 1); // Terminate the file list.
353 static void emitOneV5FileEntry(MCStreamer *MCOS, const MCDwarfFile &DwarfFile,
354 bool EmitMD5, bool HasSource,
355 Optional<MCDwarfLineStr> &LineStr) {
356 assert(!DwarfFile.Name.empty());
358 LineStr->emitRef(MCOS, DwarfFile.Name);
360 MCOS->EmitBytes(DwarfFile.Name); // FileName and...
361 MCOS->EmitBytes(StringRef("\0", 1)); // its null terminator.
363 MCOS->EmitULEB128IntValue(DwarfFile.DirIndex); // Directory number.
365 MD5::MD5Result *Cksum = DwarfFile.Checksum;
366 MCOS->EmitBinaryData(
367 StringRef(reinterpret_cast<const char *>(Cksum->Bytes.data()),
368 Cksum->Bytes.size()));
372 LineStr->emitRef(MCOS, DwarfFile.Source.getValueOr(StringRef()));
375 DwarfFile.Source.getValueOr(StringRef())); // Source and...
376 MCOS->EmitBytes(StringRef("\0", 1)); // its null terminator.
381 void MCDwarfLineTableHeader::emitV5FileDirTables(
382 MCStreamer *MCOS, Optional<MCDwarfLineStr> &LineStr,
383 StringRef CtxCompilationDir) const {
384 // The directory format, which is just a list of the directory paths. In a
385 // non-split object, these are references to .debug_line_str; in a split
386 // object, they are inline strings.
387 MCOS->EmitIntValue(1, 1);
388 MCOS->EmitULEB128IntValue(dwarf::DW_LNCT_path);
389 MCOS->EmitULEB128IntValue(LineStr ? dwarf::DW_FORM_line_strp
390 : dwarf::DW_FORM_string);
391 MCOS->EmitULEB128IntValue(MCDwarfDirs.size() + 1);
392 // Try not to emit an empty compilation directory.
393 const StringRef CompDir =
394 CompilationDir.empty() ? CtxCompilationDir : StringRef(CompilationDir);
396 // Record path strings, emit references here.
397 LineStr->emitRef(MCOS, CompDir);
398 for (const auto &Dir : MCDwarfDirs)
399 LineStr->emitRef(MCOS, Dir);
401 // The list of directory paths. Compilation directory comes first.
402 MCOS->EmitBytes(CompDir);
403 MCOS->EmitBytes(StringRef("\0", 1));
404 for (const auto &Dir : MCDwarfDirs) {
405 MCOS->EmitBytes(Dir); // The DirectoryName, and...
406 MCOS->EmitBytes(StringRef("\0", 1)); // its null terminator.
410 // The file format, which is the inline null-terminated filename and a
411 // directory index. We don't track file size/timestamp so don't emit them
412 // in the v5 table. Emit MD5 checksums and source if we have them.
413 uint64_t Entries = 2;
418 MCOS->EmitIntValue(Entries, 1);
419 MCOS->EmitULEB128IntValue(dwarf::DW_LNCT_path);
420 MCOS->EmitULEB128IntValue(LineStr ? dwarf::DW_FORM_line_strp
421 : dwarf::DW_FORM_string);
422 MCOS->EmitULEB128IntValue(dwarf::DW_LNCT_directory_index);
423 MCOS->EmitULEB128IntValue(dwarf::DW_FORM_udata);
425 MCOS->EmitULEB128IntValue(dwarf::DW_LNCT_MD5);
426 MCOS->EmitULEB128IntValue(dwarf::DW_FORM_data16);
429 MCOS->EmitULEB128IntValue(dwarf::DW_LNCT_LLVM_source);
430 MCOS->EmitULEB128IntValue(LineStr ? dwarf::DW_FORM_line_strp
431 : dwarf::DW_FORM_string);
433 // Then the counted list of files. The root file is file #0, then emit the
434 // files as provide by .file directives. To accommodate assembler source
435 // written for DWARF v4 but trying to emit v5, if we didn't see a root file
436 // explicitly, replicate file #1.
437 MCOS->EmitULEB128IntValue(MCDwarfFiles.size());
438 emitOneV5FileEntry(MCOS, RootFile.Name.empty() ? MCDwarfFiles[1] : RootFile,
439 HasAllMD5, HasSource, LineStr);
440 for (unsigned i = 1; i < MCDwarfFiles.size(); ++i)
441 emitOneV5FileEntry(MCOS, MCDwarfFiles[i], HasAllMD5, HasSource, LineStr);
444 std::pair<MCSymbol *, MCSymbol *>
445 MCDwarfLineTableHeader::Emit(MCStreamer *MCOS, MCDwarfLineTableParams Params,
446 ArrayRef<char> StandardOpcodeLengths,
447 Optional<MCDwarfLineStr> &LineStr) const {
448 MCContext &context = MCOS->getContext();
450 // Create a symbol at the beginning of the line table.
451 MCSymbol *LineStartSym = Label;
453 LineStartSym = context.createTempSymbol();
454 // Set the value of the symbol, as we are at the start of the line table.
455 MCOS->EmitLabel(LineStartSym);
457 // Create a symbol for the end of the section (to be set when we get there).
458 MCSymbol *LineEndSym = context.createTempSymbol();
460 // The first 4 bytes is the total length of the information for this
461 // compilation unit (not including these 4 bytes for the length).
463 MakeStartMinusEndExpr(*MCOS, *LineStartSym, *LineEndSym, 4), 4);
465 // Next 2 bytes is the Version.
466 // FIXME: On Darwin we still default to V2.
467 unsigned LineTableVersion = context.getDwarfVersion();
468 if (context.getObjectFileInfo()->getTargetTriple().isOSDarwin())
469 LineTableVersion = 2;
470 MCOS->EmitIntValue(LineTableVersion, 2);
472 // Keep track of the bytes between the very start and where the header length
474 unsigned PreHeaderLengthBytes = 4 + 2;
476 // In v5, we get address info next.
477 if (LineTableVersion >= 5) {
478 MCOS->EmitIntValue(context.getAsmInfo()->getCodePointerSize(), 1);
479 MCOS->EmitIntValue(0, 1); // Segment selector; same as EmitGenDwarfAranges.
480 PreHeaderLengthBytes += 2;
483 // Create a symbol for the end of the prologue (to be set when we get there).
484 MCSymbol *ProEndSym = context.createTempSymbol(); // Lprologue_end
486 // Length of the prologue, is the next 4 bytes. This is actually the length
487 // from after the length word, to the end of the prologue.
489 MakeStartMinusEndExpr(*MCOS, *LineStartSym, *ProEndSym,
490 (PreHeaderLengthBytes + 4)),
493 // Parameters of the state machine, are next.
494 MCOS->EmitIntValue(context.getAsmInfo()->getMinInstAlignment(), 1);
495 // maximum_operations_per_instruction
496 // For non-VLIW architectures this field is always 1.
497 // FIXME: VLIW architectures need to update this field accordingly.
498 if (LineTableVersion >= 4)
499 MCOS->EmitIntValue(1, 1);
500 MCOS->EmitIntValue(DWARF2_LINE_DEFAULT_IS_STMT, 1);
501 MCOS->EmitIntValue(Params.DWARF2LineBase, 1);
502 MCOS->EmitIntValue(Params.DWARF2LineRange, 1);
503 MCOS->EmitIntValue(StandardOpcodeLengths.size() + 1, 1);
505 // Standard opcode lengths
506 for (char Length : StandardOpcodeLengths)
507 MCOS->EmitIntValue(Length, 1);
509 // Put out the directory and file tables. The formats vary depending on
511 if (LineTableVersion >= 5)
512 emitV5FileDirTables(MCOS, LineStr, context.getCompilationDir());
514 emitV2FileDirTables(MCOS);
516 // This is the end of the prologue, so set the value of the symbol at the
517 // end of the prologue (that was used in a previous expression).
518 MCOS->EmitLabel(ProEndSym);
520 return std::make_pair(LineStartSym, LineEndSym);
523 void MCDwarfLineTable::EmitCU(MCObjectStreamer *MCOS,
524 MCDwarfLineTableParams Params,
525 Optional<MCDwarfLineStr> &LineStr) const {
526 MCSymbol *LineEndSym = Header.Emit(MCOS, Params, LineStr).second;
528 // Put out the line tables.
529 for (const auto &LineSec : MCLineSections.getMCLineEntries())
530 EmitDwarfLineTable(MCOS, LineSec.first, LineSec.second);
532 // This is the end of the section, so set the value of the symbol at the end
533 // of this section (that was used in a previous expression).
534 MCOS->EmitLabel(LineEndSym);
537 Expected<unsigned> MCDwarfLineTable::tryGetFile(StringRef &Directory,
539 MD5::MD5Result *Checksum,
540 Optional<StringRef> Source,
541 unsigned FileNumber) {
542 return Header.tryGetFile(Directory, FileName, Checksum, Source, FileNumber);
546 MCDwarfLineTableHeader::tryGetFile(StringRef &Directory,
548 MD5::MD5Result *Checksum,
549 Optional<StringRef> &Source,
550 unsigned FileNumber) {
551 if (Directory == CompilationDir)
553 if (FileName.empty()) {
554 FileName = "<stdin>";
557 assert(!FileName.empty());
558 // Keep track of whether any or all files have an MD5 checksum.
559 // If any files have embedded source, they all must.
560 if (MCDwarfFiles.empty()) {
561 trackMD5Usage(Checksum);
562 HasSource = (Source != None);
564 if (FileNumber == 0) {
565 // File numbers start with 1 and/or after any file numbers
566 // allocated by inline-assembler .file directives.
567 FileNumber = MCDwarfFiles.empty() ? 1 : MCDwarfFiles.size();
568 SmallString<256> Buffer;
569 auto IterBool = SourceIdMap.insert(
570 std::make_pair((Directory + Twine('\0') + FileName).toStringRef(Buffer),
572 if (!IterBool.second)
573 return IterBool.first->second;
575 // Make space for this FileNumber in the MCDwarfFiles vector if needed.
576 if (FileNumber >= MCDwarfFiles.size())
577 MCDwarfFiles.resize(FileNumber + 1);
579 // Get the new MCDwarfFile slot for this FileNumber.
580 MCDwarfFile &File = MCDwarfFiles[FileNumber];
582 // It is an error to see the same number more than once.
583 if (!File.Name.empty())
584 return make_error<StringError>("file number already allocated",
585 inconvertibleErrorCode());
587 // If any files have embedded source, they all must.
588 if (HasSource != (Source != None))
589 return make_error<StringError>("inconsistent use of embedded source",
590 inconvertibleErrorCode());
592 if (Directory.empty()) {
593 // Separate the directory part from the basename of the FileName.
594 StringRef tFileName = sys::path::filename(FileName);
595 if (!tFileName.empty()) {
596 Directory = sys::path::parent_path(FileName);
597 if (!Directory.empty())
598 FileName = tFileName;
602 // Find or make an entry in the MCDwarfDirs vector for this Directory.
603 // Capture directory name.
605 if (Directory.empty()) {
606 // For FileNames with no directories a DirIndex of 0 is used.
610 for (unsigned End = MCDwarfDirs.size(); DirIndex < End; DirIndex++) {
611 if (Directory == MCDwarfDirs[DirIndex])
614 if (DirIndex >= MCDwarfDirs.size())
615 MCDwarfDirs.push_back(Directory);
616 // The DirIndex is one based, as DirIndex of 0 is used for FileNames with
617 // no directories. MCDwarfDirs[] is unlike MCDwarfFiles[] in that the
618 // directory names are stored at MCDwarfDirs[DirIndex-1] where FileNames
619 // are stored at MCDwarfFiles[FileNumber].Name .
623 File.Name = FileName;
624 File.DirIndex = DirIndex;
625 File.Checksum = Checksum;
626 trackMD5Usage(Checksum);
627 File.Source = Source;
631 // return the allocated FileNumber.
635 /// Utility function to emit the encoding to a streamer.
636 void MCDwarfLineAddr::Emit(MCStreamer *MCOS, MCDwarfLineTableParams Params,
637 int64_t LineDelta, uint64_t AddrDelta) {
638 MCContext &Context = MCOS->getContext();
639 SmallString<256> Tmp;
640 raw_svector_ostream OS(Tmp);
641 MCDwarfLineAddr::Encode(Context, Params, LineDelta, AddrDelta, OS);
642 MCOS->EmitBytes(OS.str());
645 /// Given a special op, return the address skip amount (in units of
646 /// DWARF2_LINE_MIN_INSN_LENGTH).
647 static uint64_t SpecialAddr(MCDwarfLineTableParams Params, uint64_t op) {
648 return (op - Params.DWARF2LineOpcodeBase) / Params.DWARF2LineRange;
651 /// Utility function to encode a Dwarf pair of LineDelta and AddrDeltas.
652 void MCDwarfLineAddr::Encode(MCContext &Context, MCDwarfLineTableParams Params,
653 int64_t LineDelta, uint64_t AddrDelta,
655 uint64_t Temp, Opcode;
656 bool NeedCopy = false;
658 // The maximum address skip amount that can be encoded with a special op.
659 uint64_t MaxSpecialAddrDelta = SpecialAddr(Params, 255);
661 // Scale the address delta by the minimum instruction length.
662 AddrDelta = ScaleAddrDelta(Context, AddrDelta);
664 // A LineDelta of INT64_MAX is a signal that this is actually a
665 // DW_LNE_end_sequence. We cannot use special opcodes here, since we want the
666 // end_sequence to emit the matrix entry.
667 if (LineDelta == INT64_MAX) {
668 if (AddrDelta == MaxSpecialAddrDelta)
669 OS << char(dwarf::DW_LNS_const_add_pc);
670 else if (AddrDelta) {
671 OS << char(dwarf::DW_LNS_advance_pc);
672 encodeULEB128(AddrDelta, OS);
674 OS << char(dwarf::DW_LNS_extended_op);
676 OS << char(dwarf::DW_LNE_end_sequence);
680 // Bias the line delta by the base.
681 Temp = LineDelta - Params.DWARF2LineBase;
683 // If the line increment is out of range of a special opcode, we must encode
684 // it with DW_LNS_advance_line.
685 if (Temp >= Params.DWARF2LineRange ||
686 Temp + Params.DWARF2LineOpcodeBase > 255) {
687 OS << char(dwarf::DW_LNS_advance_line);
688 encodeSLEB128(LineDelta, OS);
691 Temp = 0 - Params.DWARF2LineBase;
695 // Use DW_LNS_copy instead of a "line +0, addr +0" special opcode.
696 if (LineDelta == 0 && AddrDelta == 0) {
697 OS << char(dwarf::DW_LNS_copy);
701 // Bias the opcode by the special opcode base.
702 Temp += Params.DWARF2LineOpcodeBase;
704 // Avoid overflow when addr_delta is large.
705 if (AddrDelta < 256 + MaxSpecialAddrDelta) {
706 // Try using a special opcode.
707 Opcode = Temp + AddrDelta * Params.DWARF2LineRange;
713 // Try using DW_LNS_const_add_pc followed by special op.
714 Opcode = Temp + (AddrDelta - MaxSpecialAddrDelta) * Params.DWARF2LineRange;
716 OS << char(dwarf::DW_LNS_const_add_pc);
722 // Otherwise use DW_LNS_advance_pc.
723 OS << char(dwarf::DW_LNS_advance_pc);
724 encodeULEB128(AddrDelta, OS);
727 OS << char(dwarf::DW_LNS_copy);
729 assert(Temp <= 255 && "Buggy special opcode encoding.");
734 // Utility function to write a tuple for .debug_abbrev.
735 static void EmitAbbrev(MCStreamer *MCOS, uint64_t Name, uint64_t Form) {
736 MCOS->EmitULEB128IntValue(Name);
737 MCOS->EmitULEB128IntValue(Form);
740 // When generating dwarf for assembly source files this emits
741 // the data for .debug_abbrev section which contains three DIEs.
742 static void EmitGenDwarfAbbrev(MCStreamer *MCOS) {
743 MCContext &context = MCOS->getContext();
744 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfAbbrevSection());
746 // DW_TAG_compile_unit DIE abbrev (1).
747 MCOS->EmitULEB128IntValue(1);
748 MCOS->EmitULEB128IntValue(dwarf::DW_TAG_compile_unit);
749 MCOS->EmitIntValue(dwarf::DW_CHILDREN_yes, 1);
750 EmitAbbrev(MCOS, dwarf::DW_AT_stmt_list, context.getDwarfVersion() >= 4
751 ? dwarf::DW_FORM_sec_offset
752 : dwarf::DW_FORM_data4);
753 if (context.getGenDwarfSectionSyms().size() > 1 &&
754 context.getDwarfVersion() >= 3) {
755 EmitAbbrev(MCOS, dwarf::DW_AT_ranges, context.getDwarfVersion() >= 4
756 ? dwarf::DW_FORM_sec_offset
757 : dwarf::DW_FORM_data4);
759 EmitAbbrev(MCOS, dwarf::DW_AT_low_pc, dwarf::DW_FORM_addr);
760 EmitAbbrev(MCOS, dwarf::DW_AT_high_pc, dwarf::DW_FORM_addr);
762 EmitAbbrev(MCOS, dwarf::DW_AT_name, dwarf::DW_FORM_string);
763 if (!context.getCompilationDir().empty())
764 EmitAbbrev(MCOS, dwarf::DW_AT_comp_dir, dwarf::DW_FORM_string);
765 StringRef DwarfDebugFlags = context.getDwarfDebugFlags();
766 if (!DwarfDebugFlags.empty())
767 EmitAbbrev(MCOS, dwarf::DW_AT_APPLE_flags, dwarf::DW_FORM_string);
768 EmitAbbrev(MCOS, dwarf::DW_AT_producer, dwarf::DW_FORM_string);
769 EmitAbbrev(MCOS, dwarf::DW_AT_language, dwarf::DW_FORM_data2);
770 EmitAbbrev(MCOS, 0, 0);
772 // DW_TAG_label DIE abbrev (2).
773 MCOS->EmitULEB128IntValue(2);
774 MCOS->EmitULEB128IntValue(dwarf::DW_TAG_label);
775 MCOS->EmitIntValue(dwarf::DW_CHILDREN_yes, 1);
776 EmitAbbrev(MCOS, dwarf::DW_AT_name, dwarf::DW_FORM_string);
777 EmitAbbrev(MCOS, dwarf::DW_AT_decl_file, dwarf::DW_FORM_data4);
778 EmitAbbrev(MCOS, dwarf::DW_AT_decl_line, dwarf::DW_FORM_data4);
779 EmitAbbrev(MCOS, dwarf::DW_AT_low_pc, dwarf::DW_FORM_addr);
780 EmitAbbrev(MCOS, dwarf::DW_AT_prototyped, dwarf::DW_FORM_flag);
781 EmitAbbrev(MCOS, 0, 0);
783 // DW_TAG_unspecified_parameters DIE abbrev (3).
784 MCOS->EmitULEB128IntValue(3);
785 MCOS->EmitULEB128IntValue(dwarf::DW_TAG_unspecified_parameters);
786 MCOS->EmitIntValue(dwarf::DW_CHILDREN_no, 1);
787 EmitAbbrev(MCOS, 0, 0);
789 // Terminate the abbreviations for this compilation unit.
790 MCOS->EmitIntValue(0, 1);
793 // When generating dwarf for assembly source files this emits the data for
794 // .debug_aranges section. This section contains a header and a table of pairs
795 // of PointerSize'ed values for the address and size of section(s) with line
797 static void EmitGenDwarfAranges(MCStreamer *MCOS,
798 const MCSymbol *InfoSectionSymbol) {
799 MCContext &context = MCOS->getContext();
801 auto &Sections = context.getGenDwarfSectionSyms();
803 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfARangesSection());
805 // This will be the length of the .debug_aranges section, first account for
806 // the size of each item in the header (see below where we emit these items).
807 int Length = 4 + 2 + 4 + 1 + 1;
809 // Figure the padding after the header before the table of address and size
810 // pairs who's values are PointerSize'ed.
811 const MCAsmInfo *asmInfo = context.getAsmInfo();
812 int AddrSize = asmInfo->getCodePointerSize();
813 int Pad = 2 * AddrSize - (Length & (2 * AddrSize - 1));
814 if (Pad == 2 * AddrSize)
818 // Add the size of the pair of PointerSize'ed values for the address and size
819 // of each section we have in the table.
820 Length += 2 * AddrSize * Sections.size();
821 // And the pair of terminating zeros.
822 Length += 2 * AddrSize;
824 // Emit the header for this section.
825 // The 4 byte length not including the 4 byte value for the length.
826 MCOS->EmitIntValue(Length - 4, 4);
827 // The 2 byte version, which is 2.
828 MCOS->EmitIntValue(2, 2);
829 // The 4 byte offset to the compile unit in the .debug_info from the start
830 // of the .debug_info.
831 if (InfoSectionSymbol)
832 MCOS->EmitSymbolValue(InfoSectionSymbol, 4,
833 asmInfo->needsDwarfSectionOffsetDirective());
835 MCOS->EmitIntValue(0, 4);
836 // The 1 byte size of an address.
837 MCOS->EmitIntValue(AddrSize, 1);
838 // The 1 byte size of a segment descriptor, we use a value of zero.
839 MCOS->EmitIntValue(0, 1);
840 // Align the header with the padding if needed, before we put out the table.
841 for(int i = 0; i < Pad; i++)
842 MCOS->EmitIntValue(0, 1);
844 // Now emit the table of pairs of PointerSize'ed values for the section
845 // addresses and sizes.
846 for (MCSection *Sec : Sections) {
847 const MCSymbol *StartSymbol = Sec->getBeginSymbol();
848 MCSymbol *EndSymbol = Sec->getEndSymbol(context);
849 assert(StartSymbol && "StartSymbol must not be NULL");
850 assert(EndSymbol && "EndSymbol must not be NULL");
852 const MCExpr *Addr = MCSymbolRefExpr::create(
853 StartSymbol, MCSymbolRefExpr::VK_None, context);
854 const MCExpr *Size = MakeStartMinusEndExpr(*MCOS,
855 *StartSymbol, *EndSymbol, 0);
856 MCOS->EmitValue(Addr, AddrSize);
857 emitAbsValue(*MCOS, Size, AddrSize);
860 // And finally the pair of terminating zeros.
861 MCOS->EmitIntValue(0, AddrSize);
862 MCOS->EmitIntValue(0, AddrSize);
865 // When generating dwarf for assembly source files this emits the data for
866 // .debug_info section which contains three parts. The header, the compile_unit
867 // DIE and a list of label DIEs.
868 static void EmitGenDwarfInfo(MCStreamer *MCOS,
869 const MCSymbol *AbbrevSectionSymbol,
870 const MCSymbol *LineSectionSymbol,
871 const MCSymbol *RangesSectionSymbol) {
872 MCContext &context = MCOS->getContext();
874 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfInfoSection());
876 // Create a symbol at the start and end of this section used in here for the
877 // expression to calculate the length in the header.
878 MCSymbol *InfoStart = context.createTempSymbol();
879 MCOS->EmitLabel(InfoStart);
880 MCSymbol *InfoEnd = context.createTempSymbol();
882 // First part: the header.
884 // The 4 byte total length of the information for this compilation unit, not
885 // including these 4 bytes.
886 const MCExpr *Length = MakeStartMinusEndExpr(*MCOS, *InfoStart, *InfoEnd, 4);
887 emitAbsValue(*MCOS, Length, 4);
889 // The 2 byte DWARF version.
890 MCOS->EmitIntValue(context.getDwarfVersion(), 2);
892 // The DWARF v5 header has unit type, address size, abbrev offset.
893 // Earlier versions have abbrev offset, address size.
894 const MCAsmInfo &AsmInfo = *context.getAsmInfo();
895 int AddrSize = AsmInfo.getCodePointerSize();
896 if (context.getDwarfVersion() >= 5) {
897 MCOS->EmitIntValue(dwarf::DW_UT_compile, 1);
898 MCOS->EmitIntValue(AddrSize, 1);
900 // The 4 byte offset to the debug abbrevs from the start of the .debug_abbrev,
901 // it is at the start of that section so this is zero.
902 if (AbbrevSectionSymbol == nullptr)
903 MCOS->EmitIntValue(0, 4);
905 MCOS->EmitSymbolValue(AbbrevSectionSymbol, 4,
906 AsmInfo.needsDwarfSectionOffsetDirective());
907 if (context.getDwarfVersion() <= 4)
908 MCOS->EmitIntValue(AddrSize, 1);
910 // Second part: the compile_unit DIE.
912 // The DW_TAG_compile_unit DIE abbrev (1).
913 MCOS->EmitULEB128IntValue(1);
915 // DW_AT_stmt_list, a 4 byte offset from the start of the .debug_line section,
916 // which is at the start of that section so this is zero.
917 if (LineSectionSymbol)
918 MCOS->EmitSymbolValue(LineSectionSymbol, 4,
919 AsmInfo.needsDwarfSectionOffsetDirective());
921 MCOS->EmitIntValue(0, 4);
923 if (RangesSectionSymbol) {
924 // There are multiple sections containing code, so we must use the
925 // .debug_ranges sections.
927 // AT_ranges, the 4 byte offset from the start of the .debug_ranges section
928 // to the address range list for this compilation unit.
929 MCOS->EmitSymbolValue(RangesSectionSymbol, 4);
931 // If we only have one non-empty code section, we can use the simpler
932 // AT_low_pc and AT_high_pc attributes.
934 // Find the first (and only) non-empty text section
935 auto &Sections = context.getGenDwarfSectionSyms();
936 const auto TextSection = Sections.begin();
937 assert(TextSection != Sections.end() && "No text section found");
939 MCSymbol *StartSymbol = (*TextSection)->getBeginSymbol();
940 MCSymbol *EndSymbol = (*TextSection)->getEndSymbol(context);
941 assert(StartSymbol && "StartSymbol must not be NULL");
942 assert(EndSymbol && "EndSymbol must not be NULL");
944 // AT_low_pc, the first address of the default .text section.
945 const MCExpr *Start = MCSymbolRefExpr::create(
946 StartSymbol, MCSymbolRefExpr::VK_None, context);
947 MCOS->EmitValue(Start, AddrSize);
949 // AT_high_pc, the last address of the default .text section.
950 const MCExpr *End = MCSymbolRefExpr::create(
951 EndSymbol, MCSymbolRefExpr::VK_None, context);
952 MCOS->EmitValue(End, AddrSize);
955 // AT_name, the name of the source file. Reconstruct from the first directory
956 // and file table entries.
957 const SmallVectorImpl<std::string> &MCDwarfDirs = context.getMCDwarfDirs();
958 if (MCDwarfDirs.size() > 0) {
959 MCOS->EmitBytes(MCDwarfDirs[0]);
960 MCOS->EmitBytes(sys::path::get_separator());
962 const SmallVectorImpl<MCDwarfFile> &MCDwarfFiles =
963 MCOS->getContext().getMCDwarfFiles();
964 MCOS->EmitBytes(MCDwarfFiles[1].Name);
965 MCOS->EmitIntValue(0, 1); // NULL byte to terminate the string.
967 // AT_comp_dir, the working directory the assembly was done in.
968 if (!context.getCompilationDir().empty()) {
969 MCOS->EmitBytes(context.getCompilationDir());
970 MCOS->EmitIntValue(0, 1); // NULL byte to terminate the string.
973 // AT_APPLE_flags, the command line arguments of the assembler tool.
974 StringRef DwarfDebugFlags = context.getDwarfDebugFlags();
975 if (!DwarfDebugFlags.empty()){
976 MCOS->EmitBytes(DwarfDebugFlags);
977 MCOS->EmitIntValue(0, 1); // NULL byte to terminate the string.
980 // AT_producer, the version of the assembler tool.
981 StringRef DwarfDebugProducer = context.getDwarfDebugProducer();
982 if (!DwarfDebugProducer.empty())
983 MCOS->EmitBytes(DwarfDebugProducer);
985 MCOS->EmitBytes(StringRef("llvm-mc (based on LLVM " PACKAGE_VERSION ")"));
986 MCOS->EmitIntValue(0, 1); // NULL byte to terminate the string.
988 // AT_language, a 4 byte value. We use DW_LANG_Mips_Assembler as the dwarf2
989 // draft has no standard code for assembler.
990 MCOS->EmitIntValue(dwarf::DW_LANG_Mips_Assembler, 2);
992 // Third part: the list of label DIEs.
994 // Loop on saved info for dwarf labels and create the DIEs for them.
995 const std::vector<MCGenDwarfLabelEntry> &Entries =
996 MCOS->getContext().getMCGenDwarfLabelEntries();
997 for (const auto &Entry : Entries) {
998 // The DW_TAG_label DIE abbrev (2).
999 MCOS->EmitULEB128IntValue(2);
1001 // AT_name, of the label without any leading underbar.
1002 MCOS->EmitBytes(Entry.getName());
1003 MCOS->EmitIntValue(0, 1); // NULL byte to terminate the string.
1005 // AT_decl_file, index into the file table.
1006 MCOS->EmitIntValue(Entry.getFileNumber(), 4);
1008 // AT_decl_line, source line number.
1009 MCOS->EmitIntValue(Entry.getLineNumber(), 4);
1011 // AT_low_pc, start address of the label.
1012 const MCExpr *AT_low_pc = MCSymbolRefExpr::create(Entry.getLabel(),
1013 MCSymbolRefExpr::VK_None, context);
1014 MCOS->EmitValue(AT_low_pc, AddrSize);
1016 // DW_AT_prototyped, a one byte flag value of 0 saying we have no prototype.
1017 MCOS->EmitIntValue(0, 1);
1019 // The DW_TAG_unspecified_parameters DIE abbrev (3).
1020 MCOS->EmitULEB128IntValue(3);
1022 // Add the NULL DIE terminating the DW_TAG_unspecified_parameters DIE's.
1023 MCOS->EmitIntValue(0, 1);
1026 // Add the NULL DIE terminating the Compile Unit DIE's.
1027 MCOS->EmitIntValue(0, 1);
1029 // Now set the value of the symbol at the end of the info section.
1030 MCOS->EmitLabel(InfoEnd);
1033 // When generating dwarf for assembly source files this emits the data for
1034 // .debug_ranges section. We only emit one range list, which spans all of the
1035 // executable sections of this file.
1036 static void EmitGenDwarfRanges(MCStreamer *MCOS) {
1037 MCContext &context = MCOS->getContext();
1038 auto &Sections = context.getGenDwarfSectionSyms();
1040 const MCAsmInfo *AsmInfo = context.getAsmInfo();
1041 int AddrSize = AsmInfo->getCodePointerSize();
1043 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfRangesSection());
1045 for (MCSection *Sec : Sections) {
1046 const MCSymbol *StartSymbol = Sec->getBeginSymbol();
1047 MCSymbol *EndSymbol = Sec->getEndSymbol(context);
1048 assert(StartSymbol && "StartSymbol must not be NULL");
1049 assert(EndSymbol && "EndSymbol must not be NULL");
1051 // Emit a base address selection entry for the start of this section
1052 const MCExpr *SectionStartAddr = MCSymbolRefExpr::create(
1053 StartSymbol, MCSymbolRefExpr::VK_None, context);
1054 MCOS->emitFill(AddrSize, 0xFF);
1055 MCOS->EmitValue(SectionStartAddr, AddrSize);
1057 // Emit a range list entry spanning this section
1058 const MCExpr *SectionSize = MakeStartMinusEndExpr(*MCOS,
1059 *StartSymbol, *EndSymbol, 0);
1060 MCOS->EmitIntValue(0, AddrSize);
1061 emitAbsValue(*MCOS, SectionSize, AddrSize);
1064 // Emit end of list entry
1065 MCOS->EmitIntValue(0, AddrSize);
1066 MCOS->EmitIntValue(0, AddrSize);
1070 // When generating dwarf for assembly source files this emits the Dwarf
1073 void MCGenDwarfInfo::Emit(MCStreamer *MCOS) {
1074 MCContext &context = MCOS->getContext();
1076 // Create the dwarf sections in this order (.debug_line already created).
1077 const MCAsmInfo *AsmInfo = context.getAsmInfo();
1078 bool CreateDwarfSectionSymbols =
1079 AsmInfo->doesDwarfUseRelocationsAcrossSections();
1080 MCSymbol *LineSectionSymbol = nullptr;
1081 if (CreateDwarfSectionSymbols)
1082 LineSectionSymbol = MCOS->getDwarfLineTableSymbol(0);
1083 MCSymbol *AbbrevSectionSymbol = nullptr;
1084 MCSymbol *InfoSectionSymbol = nullptr;
1085 MCSymbol *RangesSectionSymbol = nullptr;
1087 // Create end symbols for each section, and remove empty sections
1088 MCOS->getContext().finalizeDwarfSections(*MCOS);
1090 // If there are no sections to generate debug info for, we don't need
1092 if (MCOS->getContext().getGenDwarfSectionSyms().empty())
1095 // We only use the .debug_ranges section if we have multiple code sections,
1096 // and we are emitting a DWARF version which supports it.
1097 const bool UseRangesSection =
1098 MCOS->getContext().getGenDwarfSectionSyms().size() > 1 &&
1099 MCOS->getContext().getDwarfVersion() >= 3;
1100 CreateDwarfSectionSymbols |= UseRangesSection;
1102 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfInfoSection());
1103 if (CreateDwarfSectionSymbols) {
1104 InfoSectionSymbol = context.createTempSymbol();
1105 MCOS->EmitLabel(InfoSectionSymbol);
1107 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfAbbrevSection());
1108 if (CreateDwarfSectionSymbols) {
1109 AbbrevSectionSymbol = context.createTempSymbol();
1110 MCOS->EmitLabel(AbbrevSectionSymbol);
1112 if (UseRangesSection) {
1113 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfRangesSection());
1114 if (CreateDwarfSectionSymbols) {
1115 RangesSectionSymbol = context.createTempSymbol();
1116 MCOS->EmitLabel(RangesSectionSymbol);
1120 assert((RangesSectionSymbol != nullptr) || !UseRangesSection);
1122 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfARangesSection());
1124 // Output the data for .debug_aranges section.
1125 EmitGenDwarfAranges(MCOS, InfoSectionSymbol);
1127 if (UseRangesSection)
1128 EmitGenDwarfRanges(MCOS);
1130 // Output the data for .debug_abbrev section.
1131 EmitGenDwarfAbbrev(MCOS);
1133 // Output the data for .debug_info section.
1134 EmitGenDwarfInfo(MCOS, AbbrevSectionSymbol, LineSectionSymbol,
1135 RangesSectionSymbol);
1139 // When generating dwarf for assembly source files this is called when symbol
1140 // for a label is created. If this symbol is not a temporary and is in the
1141 // section that dwarf is being generated for, save the needed info to create
1144 void MCGenDwarfLabelEntry::Make(MCSymbol *Symbol, MCStreamer *MCOS,
1145 SourceMgr &SrcMgr, SMLoc &Loc) {
1146 // We won't create dwarf labels for temporary symbols.
1147 if (Symbol->isTemporary())
1149 MCContext &context = MCOS->getContext();
1150 // We won't create dwarf labels for symbols in sections that we are not
1151 // generating debug info for.
1152 if (!context.getGenDwarfSectionSyms().count(MCOS->getCurrentSectionOnly()))
1155 // The dwarf label's name does not have the symbol name's leading
1157 StringRef Name = Symbol->getName();
1158 if (Name.startswith("_"))
1159 Name = Name.substr(1, Name.size()-1);
1161 // Get the dwarf file number to be used for the dwarf label.
1162 unsigned FileNumber = context.getGenDwarfFileNumber();
1164 // Finding the line number is the expensive part which is why we just don't
1165 // pass it in as for some symbols we won't create a dwarf label.
1166 unsigned CurBuffer = SrcMgr.FindBufferContainingLoc(Loc);
1167 unsigned LineNumber = SrcMgr.FindLineNumber(Loc, CurBuffer);
1169 // We create a temporary symbol for use for the AT_high_pc and AT_low_pc
1170 // values so that they don't have things like an ARM thumb bit from the
1171 // original symbol. So when used they won't get a low bit set after
1173 MCSymbol *Label = context.createTempSymbol();
1174 MCOS->EmitLabel(Label);
1176 // Create and entry for the info and add it to the other entries.
1177 MCOS->getContext().addMCGenDwarfLabelEntry(
1178 MCGenDwarfLabelEntry(Name, FileNumber, LineNumber, Label));
1181 static int getDataAlignmentFactor(MCStreamer &streamer) {
1182 MCContext &context = streamer.getContext();
1183 const MCAsmInfo *asmInfo = context.getAsmInfo();
1184 int size = asmInfo->getCalleeSaveStackSlotSize();
1185 if (asmInfo->isStackGrowthDirectionUp())
1191 static unsigned getSizeForEncoding(MCStreamer &streamer,
1192 unsigned symbolEncoding) {
1193 MCContext &context = streamer.getContext();
1194 unsigned format = symbolEncoding & 0x0f;
1196 default: llvm_unreachable("Unknown Encoding");
1197 case dwarf::DW_EH_PE_absptr:
1198 case dwarf::DW_EH_PE_signed:
1199 return context.getAsmInfo()->getCodePointerSize();
1200 case dwarf::DW_EH_PE_udata2:
1201 case dwarf::DW_EH_PE_sdata2:
1203 case dwarf::DW_EH_PE_udata4:
1204 case dwarf::DW_EH_PE_sdata4:
1206 case dwarf::DW_EH_PE_udata8:
1207 case dwarf::DW_EH_PE_sdata8:
1212 static void emitFDESymbol(MCObjectStreamer &streamer, const MCSymbol &symbol,
1213 unsigned symbolEncoding, bool isEH) {
1214 MCContext &context = streamer.getContext();
1215 const MCAsmInfo *asmInfo = context.getAsmInfo();
1216 const MCExpr *v = asmInfo->getExprForFDESymbol(&symbol,
1219 unsigned size = getSizeForEncoding(streamer, symbolEncoding);
1220 if (asmInfo->doDwarfFDESymbolsUseAbsDiff() && isEH)
1221 emitAbsValue(streamer, v, size);
1223 streamer.EmitValue(v, size);
1226 static void EmitPersonality(MCStreamer &streamer, const MCSymbol &symbol,
1227 unsigned symbolEncoding) {
1228 MCContext &context = streamer.getContext();
1229 const MCAsmInfo *asmInfo = context.getAsmInfo();
1230 const MCExpr *v = asmInfo->getExprForPersonalitySymbol(&symbol,
1233 unsigned size = getSizeForEncoding(streamer, symbolEncoding);
1234 streamer.EmitValue(v, size);
1239 class FrameEmitterImpl {
1241 int InitialCFAOffset = 0;
1243 MCObjectStreamer &Streamer;
1246 FrameEmitterImpl(bool IsEH, MCObjectStreamer &Streamer)
1247 : IsEH(IsEH), Streamer(Streamer) {}
1249 /// Emit the unwind information in a compact way.
1250 void EmitCompactUnwind(const MCDwarfFrameInfo &frame);
1252 const MCSymbol &EmitCIE(const MCDwarfFrameInfo &F);
1253 void EmitFDE(const MCSymbol &cieStart, const MCDwarfFrameInfo &frame,
1254 bool LastInSection, const MCSymbol &SectionStart);
1255 void EmitCFIInstructions(ArrayRef<MCCFIInstruction> Instrs,
1256 MCSymbol *BaseLabel);
1257 void EmitCFIInstruction(const MCCFIInstruction &Instr);
1260 } // end anonymous namespace
1262 static void emitEncodingByte(MCObjectStreamer &Streamer, unsigned Encoding) {
1263 Streamer.EmitIntValue(Encoding, 1);
1266 void FrameEmitterImpl::EmitCFIInstruction(const MCCFIInstruction &Instr) {
1267 int dataAlignmentFactor = getDataAlignmentFactor(Streamer);
1268 auto *MRI = Streamer.getContext().getRegisterInfo();
1270 switch (Instr.getOperation()) {
1271 case MCCFIInstruction::OpRegister: {
1272 unsigned Reg1 = Instr.getRegister();
1273 unsigned Reg2 = Instr.getRegister2();
1275 Reg1 = MRI->getDwarfRegNumFromDwarfEHRegNum(Reg1);
1276 Reg2 = MRI->getDwarfRegNumFromDwarfEHRegNum(Reg2);
1278 Streamer.EmitIntValue(dwarf::DW_CFA_register, 1);
1279 Streamer.EmitULEB128IntValue(Reg1);
1280 Streamer.EmitULEB128IntValue(Reg2);
1283 case MCCFIInstruction::OpWindowSave:
1284 Streamer.EmitIntValue(dwarf::DW_CFA_GNU_window_save, 1);
1287 case MCCFIInstruction::OpUndefined: {
1288 unsigned Reg = Instr.getRegister();
1289 Streamer.EmitIntValue(dwarf::DW_CFA_undefined, 1);
1290 Streamer.EmitULEB128IntValue(Reg);
1293 case MCCFIInstruction::OpAdjustCfaOffset:
1294 case MCCFIInstruction::OpDefCfaOffset: {
1295 const bool IsRelative =
1296 Instr.getOperation() == MCCFIInstruction::OpAdjustCfaOffset;
1298 Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa_offset, 1);
1301 CFAOffset += Instr.getOffset();
1303 CFAOffset = -Instr.getOffset();
1305 Streamer.EmitULEB128IntValue(CFAOffset);
1309 case MCCFIInstruction::OpDefCfa: {
1310 unsigned Reg = Instr.getRegister();
1312 Reg = MRI->getDwarfRegNumFromDwarfEHRegNum(Reg);
1313 Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa, 1);
1314 Streamer.EmitULEB128IntValue(Reg);
1315 CFAOffset = -Instr.getOffset();
1316 Streamer.EmitULEB128IntValue(CFAOffset);
1320 case MCCFIInstruction::OpDefCfaRegister: {
1321 unsigned Reg = Instr.getRegister();
1323 Reg = MRI->getDwarfRegNumFromDwarfEHRegNum(Reg);
1324 Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa_register, 1);
1325 Streamer.EmitULEB128IntValue(Reg);
1329 case MCCFIInstruction::OpOffset:
1330 case MCCFIInstruction::OpRelOffset: {
1331 const bool IsRelative =
1332 Instr.getOperation() == MCCFIInstruction::OpRelOffset;
1334 unsigned Reg = Instr.getRegister();
1336 Reg = MRI->getDwarfRegNumFromDwarfEHRegNum(Reg);
1338 int Offset = Instr.getOffset();
1340 Offset -= CFAOffset;
1341 Offset = Offset / dataAlignmentFactor;
1344 Streamer.EmitIntValue(dwarf::DW_CFA_offset_extended_sf, 1);
1345 Streamer.EmitULEB128IntValue(Reg);
1346 Streamer.EmitSLEB128IntValue(Offset);
1347 } else if (Reg < 64) {
1348 Streamer.EmitIntValue(dwarf::DW_CFA_offset + Reg, 1);
1349 Streamer.EmitULEB128IntValue(Offset);
1351 Streamer.EmitIntValue(dwarf::DW_CFA_offset_extended, 1);
1352 Streamer.EmitULEB128IntValue(Reg);
1353 Streamer.EmitULEB128IntValue(Offset);
1357 case MCCFIInstruction::OpRememberState:
1358 Streamer.EmitIntValue(dwarf::DW_CFA_remember_state, 1);
1360 case MCCFIInstruction::OpRestoreState:
1361 Streamer.EmitIntValue(dwarf::DW_CFA_restore_state, 1);
1363 case MCCFIInstruction::OpSameValue: {
1364 unsigned Reg = Instr.getRegister();
1365 Streamer.EmitIntValue(dwarf::DW_CFA_same_value, 1);
1366 Streamer.EmitULEB128IntValue(Reg);
1369 case MCCFIInstruction::OpRestore: {
1370 unsigned Reg = Instr.getRegister();
1372 Reg = MRI->getDwarfRegNumFromDwarfEHRegNum(Reg);
1373 Streamer.EmitIntValue(dwarf::DW_CFA_restore | Reg, 1);
1376 case MCCFIInstruction::OpGnuArgsSize:
1377 Streamer.EmitIntValue(dwarf::DW_CFA_GNU_args_size, 1);
1378 Streamer.EmitULEB128IntValue(Instr.getOffset());
1381 case MCCFIInstruction::OpEscape:
1382 Streamer.EmitBytes(Instr.getValues());
1385 llvm_unreachable("Unhandled case in switch");
1388 /// Emit frame instructions to describe the layout of the frame.
1389 void FrameEmitterImpl::EmitCFIInstructions(ArrayRef<MCCFIInstruction> Instrs,
1390 MCSymbol *BaseLabel) {
1391 for (const MCCFIInstruction &Instr : Instrs) {
1392 MCSymbol *Label = Instr.getLabel();
1393 // Throw out move if the label is invalid.
1394 if (Label && !Label->isDefined()) continue; // Not emitted, in dead code.
1396 // Advance row if new location.
1397 if (BaseLabel && Label) {
1398 MCSymbol *ThisSym = Label;
1399 if (ThisSym != BaseLabel) {
1400 Streamer.EmitDwarfAdvanceFrameAddr(BaseLabel, ThisSym);
1401 BaseLabel = ThisSym;
1405 EmitCFIInstruction(Instr);
1409 /// Emit the unwind information in a compact way.
1410 void FrameEmitterImpl::EmitCompactUnwind(const MCDwarfFrameInfo &Frame) {
1411 MCContext &Context = Streamer.getContext();
1412 const MCObjectFileInfo *MOFI = Context.getObjectFileInfo();
1414 // range-start range-length compact-unwind-enc personality-func lsda
1415 // _foo LfooEnd-_foo 0x00000023 0 0
1416 // _bar LbarEnd-_bar 0x00000025 __gxx_personality except_tab1
1418 // .section __LD,__compact_unwind,regular,debug
1420 // # compact unwind for _foo
1422 // .set L1,LfooEnd-_foo
1428 // # compact unwind for _bar
1430 // .set L2,LbarEnd-_bar
1433 // .quad __gxx_personality
1434 // .quad except_tab1
1436 uint32_t Encoding = Frame.CompactUnwindEncoding;
1437 if (!Encoding) return;
1438 bool DwarfEHFrameOnly = (Encoding == MOFI->getCompactUnwindDwarfEHFrameOnly());
1440 // The encoding needs to know we have an LSDA.
1441 if (!DwarfEHFrameOnly && Frame.Lsda)
1442 Encoding |= 0x40000000;
1445 unsigned FDEEncoding = MOFI->getFDEEncoding();
1446 unsigned Size = getSizeForEncoding(Streamer, FDEEncoding);
1447 Streamer.EmitSymbolValue(Frame.Begin, Size);
1450 const MCExpr *Range = MakeStartMinusEndExpr(Streamer, *Frame.Begin,
1452 emitAbsValue(Streamer, Range, 4);
1455 Size = getSizeForEncoding(Streamer, dwarf::DW_EH_PE_udata4);
1456 Streamer.EmitIntValue(Encoding, Size);
1458 // Personality Function
1459 Size = getSizeForEncoding(Streamer, dwarf::DW_EH_PE_absptr);
1460 if (!DwarfEHFrameOnly && Frame.Personality)
1461 Streamer.EmitSymbolValue(Frame.Personality, Size);
1463 Streamer.EmitIntValue(0, Size); // No personality fn
1466 Size = getSizeForEncoding(Streamer, Frame.LsdaEncoding);
1467 if (!DwarfEHFrameOnly && Frame.Lsda)
1468 Streamer.EmitSymbolValue(Frame.Lsda, Size);
1470 Streamer.EmitIntValue(0, Size); // No LSDA
1473 static unsigned getCIEVersion(bool IsEH, unsigned DwarfVersion) {
1476 switch (DwarfVersion) {
1485 llvm_unreachable("Unknown version");
1488 const MCSymbol &FrameEmitterImpl::EmitCIE(const MCDwarfFrameInfo &Frame) {
1489 MCContext &context = Streamer.getContext();
1490 const MCRegisterInfo *MRI = context.getRegisterInfo();
1491 const MCObjectFileInfo *MOFI = context.getObjectFileInfo();
1493 MCSymbol *sectionStart = context.createTempSymbol();
1494 Streamer.EmitLabel(sectionStart);
1496 MCSymbol *sectionEnd = context.createTempSymbol();
1499 const MCExpr *Length =
1500 MakeStartMinusEndExpr(Streamer, *sectionStart, *sectionEnd, 4);
1501 emitAbsValue(Streamer, Length, 4);
1504 unsigned CIE_ID = IsEH ? 0 : -1;
1505 Streamer.EmitIntValue(CIE_ID, 4);
1508 uint8_t CIEVersion = getCIEVersion(IsEH, context.getDwarfVersion());
1509 Streamer.EmitIntValue(CIEVersion, 1);
1511 // Augmentation String
1512 SmallString<8> Augmentation;
1514 Augmentation += "z";
1515 if (Frame.Personality)
1516 Augmentation += "P";
1518 Augmentation += "L";
1519 Augmentation += "R";
1520 if (Frame.IsSignalFrame)
1521 Augmentation += "S";
1522 Streamer.EmitBytes(Augmentation);
1524 Streamer.EmitIntValue(0, 1);
1526 if (CIEVersion >= 4) {
1528 Streamer.EmitIntValue(context.getAsmInfo()->getCodePointerSize(), 1);
1530 // Segment Descriptor Size
1531 Streamer.EmitIntValue(0, 1);
1534 // Code Alignment Factor
1535 Streamer.EmitULEB128IntValue(context.getAsmInfo()->getMinInstAlignment());
1537 // Data Alignment Factor
1538 Streamer.EmitSLEB128IntValue(getDataAlignmentFactor(Streamer));
1540 // Return Address Register
1541 unsigned RAReg = Frame.RAReg;
1542 if (RAReg == static_cast<unsigned>(INT_MAX))
1543 RAReg = MRI->getDwarfRegNum(MRI->getRARegister(), IsEH);
1545 if (CIEVersion == 1) {
1546 assert(RAReg <= 255 &&
1547 "DWARF 2 encodes return_address_register in one byte");
1548 Streamer.EmitIntValue(RAReg, 1);
1550 Streamer.EmitULEB128IntValue(RAReg);
1553 // Augmentation Data Length (optional)
1554 unsigned augmentationLength = 0;
1556 if (Frame.Personality) {
1557 // Personality Encoding
1558 augmentationLength += 1;
1560 augmentationLength +=
1561 getSizeForEncoding(Streamer, Frame.PersonalityEncoding);
1564 augmentationLength += 1;
1565 // Encoding of the FDE pointers
1566 augmentationLength += 1;
1568 Streamer.EmitULEB128IntValue(augmentationLength);
1570 // Augmentation Data (optional)
1571 if (Frame.Personality) {
1572 // Personality Encoding
1573 emitEncodingByte(Streamer, Frame.PersonalityEncoding);
1575 EmitPersonality(Streamer, *Frame.Personality, Frame.PersonalityEncoding);
1579 emitEncodingByte(Streamer, Frame.LsdaEncoding);
1581 // Encoding of the FDE pointers
1582 emitEncodingByte(Streamer, MOFI->getFDEEncoding());
1585 // Initial Instructions
1587 const MCAsmInfo *MAI = context.getAsmInfo();
1588 if (!Frame.IsSimple) {
1589 const std::vector<MCCFIInstruction> &Instructions =
1590 MAI->getInitialFrameState();
1591 EmitCFIInstructions(Instructions, nullptr);
1594 InitialCFAOffset = CFAOffset;
1597 Streamer.EmitValueToAlignment(IsEH ? 4 : MAI->getCodePointerSize());
1599 Streamer.EmitLabel(sectionEnd);
1600 return *sectionStart;
1603 void FrameEmitterImpl::EmitFDE(const MCSymbol &cieStart,
1604 const MCDwarfFrameInfo &frame,
1606 const MCSymbol &SectionStart) {
1607 MCContext &context = Streamer.getContext();
1608 MCSymbol *fdeStart = context.createTempSymbol();
1609 MCSymbol *fdeEnd = context.createTempSymbol();
1610 const MCObjectFileInfo *MOFI = context.getObjectFileInfo();
1612 CFAOffset = InitialCFAOffset;
1615 const MCExpr *Length = MakeStartMinusEndExpr(Streamer, *fdeStart, *fdeEnd, 0);
1616 emitAbsValue(Streamer, Length, 4);
1618 Streamer.EmitLabel(fdeStart);
1621 const MCAsmInfo *asmInfo = context.getAsmInfo();
1623 const MCExpr *offset =
1624 MakeStartMinusEndExpr(Streamer, cieStart, *fdeStart, 0);
1625 emitAbsValue(Streamer, offset, 4);
1626 } else if (!asmInfo->doesDwarfUseRelocationsAcrossSections()) {
1627 const MCExpr *offset =
1628 MakeStartMinusEndExpr(Streamer, SectionStart, cieStart, 0);
1629 emitAbsValue(Streamer, offset, 4);
1631 Streamer.EmitSymbolValue(&cieStart, 4);
1635 unsigned PCEncoding =
1636 IsEH ? MOFI->getFDEEncoding() : (unsigned)dwarf::DW_EH_PE_absptr;
1637 unsigned PCSize = getSizeForEncoding(Streamer, PCEncoding);
1638 emitFDESymbol(Streamer, *frame.Begin, PCEncoding, IsEH);
1641 const MCExpr *Range =
1642 MakeStartMinusEndExpr(Streamer, *frame.Begin, *frame.End, 0);
1643 emitAbsValue(Streamer, Range, PCSize);
1646 // Augmentation Data Length
1647 unsigned augmentationLength = 0;
1650 augmentationLength += getSizeForEncoding(Streamer, frame.LsdaEncoding);
1652 Streamer.EmitULEB128IntValue(augmentationLength);
1654 // Augmentation Data
1656 emitFDESymbol(Streamer, *frame.Lsda, frame.LsdaEncoding, true);
1659 // Call Frame Instructions
1660 EmitCFIInstructions(frame.Instructions, frame.Begin);
1663 // The size of a .eh_frame section has to be a multiple of the alignment
1664 // since a null CIE is interpreted as the end. Old systems overaligned
1665 // .eh_frame, so we do too and account for it in the last FDE.
1666 unsigned Align = LastInSection ? asmInfo->getCodePointerSize() : PCSize;
1667 Streamer.EmitValueToAlignment(Align);
1669 Streamer.EmitLabel(fdeEnd);
1675 static const CIEKey getEmptyKey() {
1676 return CIEKey(nullptr, 0, -1, false, false, static_cast<unsigned>(INT_MAX));
1679 static const CIEKey getTombstoneKey() {
1680 return CIEKey(nullptr, -1, 0, false, false, static_cast<unsigned>(INT_MAX));
1683 CIEKey(const MCSymbol *Personality, unsigned PersonalityEncoding,
1684 unsigned LSDAEncoding, bool IsSignalFrame, bool IsSimple,
1686 : Personality(Personality), PersonalityEncoding(PersonalityEncoding),
1687 LsdaEncoding(LSDAEncoding), IsSignalFrame(IsSignalFrame),
1688 IsSimple(IsSimple), RAReg(RAReg) {}
1690 explicit CIEKey(const MCDwarfFrameInfo &Frame)
1691 : Personality(Frame.Personality),
1692 PersonalityEncoding(Frame.PersonalityEncoding),
1693 LsdaEncoding(Frame.LsdaEncoding), IsSignalFrame(Frame.IsSignalFrame),
1694 IsSimple(Frame.IsSimple), RAReg(Frame.RAReg) {}
1696 const MCSymbol *Personality;
1697 unsigned PersonalityEncoding;
1698 unsigned LsdaEncoding;
1704 } // end anonymous namespace
1708 template <> struct DenseMapInfo<CIEKey> {
1709 static CIEKey getEmptyKey() { return CIEKey::getEmptyKey(); }
1710 static CIEKey getTombstoneKey() { return CIEKey::getTombstoneKey(); }
1712 static unsigned getHashValue(const CIEKey &Key) {
1713 return static_cast<unsigned>(
1714 hash_combine(Key.Personality, Key.PersonalityEncoding, Key.LsdaEncoding,
1715 Key.IsSignalFrame, Key.IsSimple, Key.RAReg));
1718 static bool isEqual(const CIEKey &LHS, const CIEKey &RHS) {
1719 return LHS.Personality == RHS.Personality &&
1720 LHS.PersonalityEncoding == RHS.PersonalityEncoding &&
1721 LHS.LsdaEncoding == RHS.LsdaEncoding &&
1722 LHS.IsSignalFrame == RHS.IsSignalFrame &&
1723 LHS.IsSimple == RHS.IsSimple &&
1724 LHS.RAReg == RHS.RAReg;
1728 } // end namespace llvm
1730 void MCDwarfFrameEmitter::Emit(MCObjectStreamer &Streamer, MCAsmBackend *MAB,
1732 Streamer.generateCompactUnwindEncodings(MAB);
1734 MCContext &Context = Streamer.getContext();
1735 const MCObjectFileInfo *MOFI = Context.getObjectFileInfo();
1736 const MCAsmInfo *AsmInfo = Context.getAsmInfo();
1737 FrameEmitterImpl Emitter(IsEH, Streamer);
1738 ArrayRef<MCDwarfFrameInfo> FrameArray = Streamer.getDwarfFrameInfos();
1740 // Emit the compact unwind info if available.
1741 bool NeedsEHFrameSection = !MOFI->getSupportsCompactUnwindWithoutEHFrame();
1742 if (IsEH && MOFI->getCompactUnwindSection()) {
1743 bool SectionEmitted = false;
1744 for (const MCDwarfFrameInfo &Frame : FrameArray) {
1745 if (Frame.CompactUnwindEncoding == 0) continue;
1746 if (!SectionEmitted) {
1747 Streamer.SwitchSection(MOFI->getCompactUnwindSection());
1748 Streamer.EmitValueToAlignment(AsmInfo->getCodePointerSize());
1749 SectionEmitted = true;
1751 NeedsEHFrameSection |=
1752 Frame.CompactUnwindEncoding ==
1753 MOFI->getCompactUnwindDwarfEHFrameOnly();
1754 Emitter.EmitCompactUnwind(Frame);
1758 if (!NeedsEHFrameSection) return;
1760 MCSection &Section =
1761 IsEH ? *const_cast<MCObjectFileInfo *>(MOFI)->getEHFrameSection()
1762 : *MOFI->getDwarfFrameSection();
1764 Streamer.SwitchSection(&Section);
1765 MCSymbol *SectionStart = Context.createTempSymbol();
1766 Streamer.EmitLabel(SectionStart);
1768 DenseMap<CIEKey, const MCSymbol *> CIEStarts;
1770 const MCSymbol *DummyDebugKey = nullptr;
1771 bool CanOmitDwarf = MOFI->getOmitDwarfIfHaveCompactUnwind();
1772 for (auto I = FrameArray.begin(), E = FrameArray.end(); I != E;) {
1773 const MCDwarfFrameInfo &Frame = *I;
1775 if (CanOmitDwarf && Frame.CompactUnwindEncoding !=
1776 MOFI->getCompactUnwindDwarfEHFrameOnly())
1777 // Don't generate an EH frame if we don't need one. I.e., it's taken care
1778 // of by the compact unwind encoding.
1782 const MCSymbol *&CIEStart = IsEH ? CIEStarts[Key] : DummyDebugKey;
1784 CIEStart = &Emitter.EmitCIE(Frame);
1786 Emitter.EmitFDE(*CIEStart, Frame, I == E, *SectionStart);
1790 void MCDwarfFrameEmitter::EmitAdvanceLoc(MCObjectStreamer &Streamer,
1791 uint64_t AddrDelta) {
1792 MCContext &Context = Streamer.getContext();
1793 SmallString<256> Tmp;
1794 raw_svector_ostream OS(Tmp);
1795 MCDwarfFrameEmitter::EncodeAdvanceLoc(Context, AddrDelta, OS);
1796 Streamer.EmitBytes(OS.str());
1799 void MCDwarfFrameEmitter::EncodeAdvanceLoc(MCContext &Context,
1802 // Scale the address delta by the minimum instruction length.
1803 AddrDelta = ScaleAddrDelta(Context, AddrDelta);
1805 support::endianness E =
1806 Context.getAsmInfo()->isLittleEndian() ? support::little : support::big;
1807 if (AddrDelta == 0) {
1808 } else if (isUIntN(6, AddrDelta)) {
1809 uint8_t Opcode = dwarf::DW_CFA_advance_loc | AddrDelta;
1811 } else if (isUInt<8>(AddrDelta)) {
1812 OS << uint8_t(dwarf::DW_CFA_advance_loc1);
1813 OS << uint8_t(AddrDelta);
1814 } else if (isUInt<16>(AddrDelta)) {
1815 OS << uint8_t(dwarf::DW_CFA_advance_loc2);
1816 support::endian::write<uint16_t>(OS, AddrDelta, E);
1818 assert(isUInt<32>(AddrDelta));
1819 OS << uint8_t(dwarf::DW_CFA_advance_loc4);
1820 support::endian::write<uint32_t>(OS, AddrDelta, E);