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/MC/MCAsmInfo.h"
12 #include "llvm/MC/MCContext.h"
13 #include "llvm/MC/MCObjectFileInfo.h"
14 #include "llvm/MC/MCObjectWriter.h"
15 #include "llvm/MC/MCRegisterInfo.h"
16 #include "llvm/MC/MCStreamer.h"
17 #include "llvm/MC/MCSymbol.h"
18 #include "llvm/MC/MCExpr.h"
19 #include "llvm/Support/Debug.h"
20 #include "llvm/Support/ErrorHandling.h"
21 #include "llvm/Support/raw_ostream.h"
22 #include "llvm/Support/Path.h"
23 #include "llvm/Support/SourceMgr.h"
24 #include "llvm/ADT/FoldingSet.h"
25 #include "llvm/ADT/SmallString.h"
26 #include "llvm/ADT/Twine.h"
27 #include "llvm/Config/config.h"
30 // Given a special op, return the address skip amount (in units of
31 // DWARF2_LINE_MIN_INSN_LENGTH.
32 #define SPECIAL_ADDR(op) (((op) - DWARF2_LINE_OPCODE_BASE)/DWARF2_LINE_RANGE)
34 // The maximum address skip amount that can be encoded with a special op.
35 #define MAX_SPECIAL_ADDR_DELTA SPECIAL_ADDR(255)
37 // First special line opcode - leave room for the standard opcodes.
38 // Note: If you want to change this, you'll have to update the
39 // "standard_opcode_lengths" table that is emitted in DwarfFileTable::Emit().
40 #define DWARF2_LINE_OPCODE_BASE 13
42 // Minimum line offset in a special line info. opcode. This value
43 // was chosen to give a reasonable range of values.
44 #define DWARF2_LINE_BASE -5
46 // Range of line offsets in a special line info. opcode.
47 #define DWARF2_LINE_RANGE 14
49 // Define the architecture-dependent minimum instruction length (in bytes).
50 // This value should be rather too small than too big.
51 #define DWARF2_LINE_MIN_INSN_LENGTH 1
53 // Note: when DWARF2_LINE_MIN_INSN_LENGTH == 1 which is the current setting,
54 // this routine is a nop and will be optimized away.
55 static inline uint64_t ScaleAddrDelta(uint64_t AddrDelta) {
56 if (DWARF2_LINE_MIN_INSN_LENGTH == 1)
58 if (AddrDelta % DWARF2_LINE_MIN_INSN_LENGTH != 0) {
59 // TODO: report this error, but really only once.
62 return AddrDelta / DWARF2_LINE_MIN_INSN_LENGTH;
66 // This is called when an instruction is assembled into the specified section
67 // and if there is information from the last .loc directive that has yet to have
68 // a line entry made for it is made.
70 void MCLineEntry::Make(MCStreamer *MCOS, const MCSection *Section) {
71 if (!MCOS->getContext().getDwarfLocSeen())
74 // Create a symbol at in the current section for use in the line entry.
75 MCSymbol *LineSym = MCOS->getContext().CreateTempSymbol();
76 // Set the value of the symbol to use for the MCLineEntry.
77 MCOS->EmitLabel(LineSym);
79 // Get the current .loc info saved in the context.
80 const MCDwarfLoc &DwarfLoc = MCOS->getContext().getCurrentDwarfLoc();
82 // Create a (local) line entry with the symbol and the current .loc info.
83 MCLineEntry LineEntry(LineSym, DwarfLoc);
85 // clear DwarfLocSeen saying the current .loc info is now used.
86 MCOS->getContext().ClearDwarfLocSeen();
88 // Get the MCLineSection for this section, if one does not exist for this
90 const DenseMap<const MCSection *, MCLineSection *> &MCLineSections =
91 MCOS->getContext().getMCLineSections();
92 MCLineSection *LineSection = MCLineSections.lookup(Section);
94 // Create a new MCLineSection. This will be deleted after the dwarf line
95 // table is created using it by iterating through the MCLineSections
97 LineSection = new MCLineSection;
98 // Save a pointer to the new LineSection into the MCLineSections DenseMap.
99 MCOS->getContext().addMCLineSection(Section, LineSection);
102 // Add the line entry to this section's entries.
103 LineSection->addLineEntry(LineEntry);
107 // This helper routine returns an expression of End - Start + IntVal .
109 static inline const MCExpr *MakeStartMinusEndExpr(const MCStreamer &MCOS,
110 const MCSymbol &Start,
113 MCSymbolRefExpr::VariantKind Variant = MCSymbolRefExpr::VK_None;
115 MCSymbolRefExpr::Create(&End, Variant, MCOS.getContext());
117 MCSymbolRefExpr::Create(&Start, Variant, MCOS.getContext());
119 MCBinaryExpr::Create(MCBinaryExpr::Sub, Res, RHS, MCOS.getContext());
121 MCConstantExpr::Create(IntVal, MCOS.getContext());
123 MCBinaryExpr::Create(MCBinaryExpr::Sub, Res1, Res2, MCOS.getContext());
128 // This emits the Dwarf line table for the specified section from the entries
129 // in the LineSection.
131 static inline void EmitDwarfLineTable(MCStreamer *MCOS,
132 const MCSection *Section,
133 const MCLineSection *LineSection) {
134 unsigned FileNum = 1;
135 unsigned LastLine = 1;
137 unsigned Flags = DWARF2_LINE_DEFAULT_IS_STMT ? DWARF2_FLAG_IS_STMT : 0;
139 MCSymbol *LastLabel = NULL;
141 // Loop through each MCLineEntry and encode the dwarf line number table.
142 for (MCLineSection::const_iterator
143 it = LineSection->getMCLineEntries()->begin(),
144 ie = LineSection->getMCLineEntries()->end(); it != ie; ++it) {
146 if (FileNum != it->getFileNum()) {
147 FileNum = it->getFileNum();
148 MCOS->EmitIntValue(dwarf::DW_LNS_set_file, 1);
149 MCOS->EmitULEB128IntValue(FileNum);
151 if (Column != it->getColumn()) {
152 Column = it->getColumn();
153 MCOS->EmitIntValue(dwarf::DW_LNS_set_column, 1);
154 MCOS->EmitULEB128IntValue(Column);
156 if (Isa != it->getIsa()) {
158 MCOS->EmitIntValue(dwarf::DW_LNS_set_isa, 1);
159 MCOS->EmitULEB128IntValue(Isa);
161 if ((it->getFlags() ^ Flags) & DWARF2_FLAG_IS_STMT) {
162 Flags = it->getFlags();
163 MCOS->EmitIntValue(dwarf::DW_LNS_negate_stmt, 1);
165 if (it->getFlags() & DWARF2_FLAG_BASIC_BLOCK)
166 MCOS->EmitIntValue(dwarf::DW_LNS_set_basic_block, 1);
167 if (it->getFlags() & DWARF2_FLAG_PROLOGUE_END)
168 MCOS->EmitIntValue(dwarf::DW_LNS_set_prologue_end, 1);
169 if (it->getFlags() & DWARF2_FLAG_EPILOGUE_BEGIN)
170 MCOS->EmitIntValue(dwarf::DW_LNS_set_epilogue_begin, 1);
172 int64_t LineDelta = static_cast<int64_t>(it->getLine()) - LastLine;
173 MCSymbol *Label = it->getLabel();
175 // At this point we want to emit/create the sequence to encode the delta in
176 // line numbers and the increment of the address from the previous Label
177 // and the current Label.
178 const MCAsmInfo &asmInfo = MCOS->getContext().getAsmInfo();
179 MCOS->EmitDwarfAdvanceLineAddr(LineDelta, LastLabel, Label,
180 asmInfo.getPointerSize());
182 LastLine = it->getLine();
186 // Emit a DW_LNE_end_sequence for the end of the section.
187 // Using the pointer Section create a temporary label at the end of the
188 // section and use that and the LastLabel to compute the address delta
189 // and use INT64_MAX as the line delta which is the signal that this is
190 // actually a DW_LNE_end_sequence.
192 // Switch to the section to be able to create a symbol at its end.
193 MCOS->SwitchSection(Section);
195 MCContext &context = MCOS->getContext();
196 // Create a symbol at the end of the section.
197 MCSymbol *SectionEnd = context.CreateTempSymbol();
198 // Set the value of the symbol, as we are at the end of the section.
199 MCOS->EmitLabel(SectionEnd);
201 // Switch back the the dwarf line section.
202 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfLineSection());
204 const MCAsmInfo &asmInfo = MCOS->getContext().getAsmInfo();
205 MCOS->EmitDwarfAdvanceLineAddr(INT64_MAX, LastLabel, SectionEnd,
206 asmInfo.getPointerSize());
210 // This emits the Dwarf file and the line tables.
212 void MCDwarfFileTable::Emit(MCStreamer *MCOS) {
213 MCContext &context = MCOS->getContext();
214 // Switch to the section where the table will be emitted into.
215 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfLineSection());
217 // Create a symbol at the beginning of this section.
218 MCSymbol *LineStartSym = context.CreateTempSymbol();
219 // Set the value of the symbol, as we are at the start of the section.
220 MCOS->EmitLabel(LineStartSym);
222 // Create a symbol for the end of the section (to be set when we get there).
223 MCSymbol *LineEndSym = context.CreateTempSymbol();
225 // The first 4 bytes is the total length of the information for this
226 // compilation unit (not including these 4 bytes for the length).
227 MCOS->EmitAbsValue(MakeStartMinusEndExpr(*MCOS, *LineStartSym, *LineEndSym,4),
230 // Next 2 bytes is the Version, which is Dwarf 2.
231 MCOS->EmitIntValue(2, 2);
233 // Create a symbol for the end of the prologue (to be set when we get there).
234 MCSymbol *ProEndSym = context.CreateTempSymbol(); // Lprologue_end
236 // Length of the prologue, is the next 4 bytes. Which is the start of the
237 // section to the end of the prologue. Not including the 4 bytes for the
238 // total length, the 2 bytes for the version, and these 4 bytes for the
239 // length of the prologue.
240 MCOS->EmitAbsValue(MakeStartMinusEndExpr(*MCOS, *LineStartSym, *ProEndSym,
244 // Parameters of the state machine, are next.
245 MCOS->EmitIntValue(DWARF2_LINE_MIN_INSN_LENGTH, 1);
246 MCOS->EmitIntValue(DWARF2_LINE_DEFAULT_IS_STMT, 1);
247 MCOS->EmitIntValue(DWARF2_LINE_BASE, 1);
248 MCOS->EmitIntValue(DWARF2_LINE_RANGE, 1);
249 MCOS->EmitIntValue(DWARF2_LINE_OPCODE_BASE, 1);
251 // Standard opcode lengths
252 MCOS->EmitIntValue(0, 1); // length of DW_LNS_copy
253 MCOS->EmitIntValue(1, 1); // length of DW_LNS_advance_pc
254 MCOS->EmitIntValue(1, 1); // length of DW_LNS_advance_line
255 MCOS->EmitIntValue(1, 1); // length of DW_LNS_set_file
256 MCOS->EmitIntValue(1, 1); // length of DW_LNS_set_column
257 MCOS->EmitIntValue(0, 1); // length of DW_LNS_negate_stmt
258 MCOS->EmitIntValue(0, 1); // length of DW_LNS_set_basic_block
259 MCOS->EmitIntValue(0, 1); // length of DW_LNS_const_add_pc
260 MCOS->EmitIntValue(1, 1); // length of DW_LNS_fixed_advance_pc
261 MCOS->EmitIntValue(0, 1); // length of DW_LNS_set_prologue_end
262 MCOS->EmitIntValue(0, 1); // length of DW_LNS_set_epilogue_begin
263 MCOS->EmitIntValue(1, 1); // DW_LNS_set_isa
265 // Put out the directory and file tables.
267 // First the directory table.
268 const std::vector<StringRef> &MCDwarfDirs =
269 context.getMCDwarfDirs();
270 for (unsigned i = 0; i < MCDwarfDirs.size(); i++) {
271 MCOS->EmitBytes(MCDwarfDirs[i], 0); // the DirectoryName
272 MCOS->EmitBytes(StringRef("\0", 1), 0); // the null term. of the string
274 MCOS->EmitIntValue(0, 1); // Terminate the directory list
276 // Second the file table.
277 const std::vector<MCDwarfFile *> &MCDwarfFiles =
278 MCOS->getContext().getMCDwarfFiles();
279 for (unsigned i = 1; i < MCDwarfFiles.size(); i++) {
280 MCOS->EmitBytes(MCDwarfFiles[i]->getName(), 0); // FileName
281 MCOS->EmitBytes(StringRef("\0", 1), 0); // the null term. of the string
283 MCOS->EmitULEB128IntValue(MCDwarfFiles[i]->getDirIndex());
284 MCOS->EmitIntValue(0, 1); // last modification timestamp (always 0)
285 MCOS->EmitIntValue(0, 1); // filesize (always 0)
287 MCOS->EmitIntValue(0, 1); // Terminate the file list
289 // This is the end of the prologue, so set the value of the symbol at the
290 // end of the prologue (that was used in a previous expression).
291 MCOS->EmitLabel(ProEndSym);
293 // Put out the line tables.
294 const DenseMap<const MCSection *, MCLineSection *> &MCLineSections =
295 MCOS->getContext().getMCLineSections();
296 const std::vector<const MCSection *> &MCLineSectionOrder =
297 MCOS->getContext().getMCLineSectionOrder();
298 for (std::vector<const MCSection*>::const_iterator it =
299 MCLineSectionOrder.begin(), ie = MCLineSectionOrder.end(); it != ie;
301 const MCSection *Sec = *it;
302 const MCLineSection *Line = MCLineSections.lookup(Sec);
303 EmitDwarfLineTable(MCOS, Sec, Line);
305 // Now delete the MCLineSections that were created in MCLineEntry::Make()
306 // and used to emit the line table.
310 if (MCOS->getContext().getAsmInfo().getLinkerRequiresNonEmptyDwarfLines()
311 && MCLineSectionOrder.begin() == MCLineSectionOrder.end()) {
312 // The darwin9 linker has a bug (see PR8715). For for 32-bit architectures
314 // total_length >= prologue_length + 10
315 // We are 4 bytes short, since we have total_length = 51 and
316 // prologue_length = 45
318 // The regular end_sequence should be sufficient.
319 MCDwarfLineAddr::Emit(MCOS, INT64_MAX, 0);
322 // This is the end of the section, so set the value of the symbol at the end
323 // of this section (that was used in a previous expression).
324 MCOS->EmitLabel(LineEndSym);
327 /// Utility function to write the encoding to an object writer.
328 void MCDwarfLineAddr::Write(MCObjectWriter *OW, int64_t LineDelta,
329 uint64_t AddrDelta) {
330 SmallString<256> Tmp;
331 raw_svector_ostream OS(Tmp);
332 MCDwarfLineAddr::Encode(LineDelta, AddrDelta, OS);
333 OW->WriteBytes(OS.str());
336 /// Utility function to emit the encoding to a streamer.
337 void MCDwarfLineAddr::Emit(MCStreamer *MCOS, int64_t LineDelta,
338 uint64_t AddrDelta) {
339 SmallString<256> Tmp;
340 raw_svector_ostream OS(Tmp);
341 MCDwarfLineAddr::Encode(LineDelta, AddrDelta, OS);
342 MCOS->EmitBytes(OS.str(), /*AddrSpace=*/0);
345 /// Utility function to encode a Dwarf pair of LineDelta and AddrDeltas.
346 void MCDwarfLineAddr::Encode(int64_t LineDelta, uint64_t AddrDelta,
348 uint64_t Temp, Opcode;
349 bool NeedCopy = false;
351 // Scale the address delta by the minimum instruction length.
352 AddrDelta = ScaleAddrDelta(AddrDelta);
354 // A LineDelta of INT64_MAX is a signal that this is actually a
355 // DW_LNE_end_sequence. We cannot use special opcodes here, since we want the
356 // end_sequence to emit the matrix entry.
357 if (LineDelta == INT64_MAX) {
358 if (AddrDelta == MAX_SPECIAL_ADDR_DELTA)
359 OS << char(dwarf::DW_LNS_const_add_pc);
361 OS << char(dwarf::DW_LNS_advance_pc);
362 MCObjectWriter::EncodeULEB128(AddrDelta, OS);
364 OS << char(dwarf::DW_LNS_extended_op);
366 OS << char(dwarf::DW_LNE_end_sequence);
370 // Bias the line delta by the base.
371 Temp = LineDelta - DWARF2_LINE_BASE;
373 // If the line increment is out of range of a special opcode, we must encode
374 // it with DW_LNS_advance_line.
375 if (Temp >= DWARF2_LINE_RANGE) {
376 OS << char(dwarf::DW_LNS_advance_line);
377 MCObjectWriter::EncodeSLEB128(LineDelta, OS);
380 Temp = 0 - DWARF2_LINE_BASE;
384 // Use DW_LNS_copy instead of a "line +0, addr +0" special opcode.
385 if (LineDelta == 0 && AddrDelta == 0) {
386 OS << char(dwarf::DW_LNS_copy);
390 // Bias the opcode by the special opcode base.
391 Temp += DWARF2_LINE_OPCODE_BASE;
393 // Avoid overflow when addr_delta is large.
394 if (AddrDelta < 256 + MAX_SPECIAL_ADDR_DELTA) {
395 // Try using a special opcode.
396 Opcode = Temp + AddrDelta * DWARF2_LINE_RANGE;
402 // Try using DW_LNS_const_add_pc followed by special op.
403 Opcode = Temp + (AddrDelta - MAX_SPECIAL_ADDR_DELTA) * DWARF2_LINE_RANGE;
405 OS << char(dwarf::DW_LNS_const_add_pc);
411 // Otherwise use DW_LNS_advance_pc.
412 OS << char(dwarf::DW_LNS_advance_pc);
413 MCObjectWriter::EncodeULEB128(AddrDelta, OS);
416 OS << char(dwarf::DW_LNS_copy);
421 void MCDwarfFile::print(raw_ostream &OS) const {
422 OS << '"' << getName() << '"';
425 void MCDwarfFile::dump() const {
429 // Utility function to write a tuple for .debug_abbrev.
430 static void EmitAbbrev(MCStreamer *MCOS, uint64_t Name, uint64_t Form) {
431 MCOS->EmitULEB128IntValue(Name);
432 MCOS->EmitULEB128IntValue(Form);
435 // When generating dwarf for assembly source files this emits
436 // the data for .debug_abbrev section which contains three DIEs.
437 static void EmitGenDwarfAbbrev(MCStreamer *MCOS) {
438 MCContext &context = MCOS->getContext();
439 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfAbbrevSection());
441 // DW_TAG_compile_unit DIE abbrev (1).
442 MCOS->EmitULEB128IntValue(1);
443 MCOS->EmitULEB128IntValue(dwarf::DW_TAG_compile_unit);
444 MCOS->EmitIntValue(dwarf::DW_CHILDREN_yes, 1);
445 EmitAbbrev(MCOS, dwarf::DW_AT_stmt_list, dwarf::DW_FORM_data4);
446 EmitAbbrev(MCOS, dwarf::DW_AT_low_pc, dwarf::DW_FORM_addr);
447 EmitAbbrev(MCOS, dwarf::DW_AT_high_pc, dwarf::DW_FORM_addr);
448 EmitAbbrev(MCOS, dwarf::DW_AT_name, dwarf::DW_FORM_string);
449 EmitAbbrev(MCOS, dwarf::DW_AT_comp_dir, dwarf::DW_FORM_string);
450 StringRef DwarfDebugFlags = context.getDwarfDebugFlags();
451 if (!DwarfDebugFlags.empty())
452 EmitAbbrev(MCOS, dwarf::DW_AT_APPLE_flags, dwarf::DW_FORM_string);
453 EmitAbbrev(MCOS, dwarf::DW_AT_producer, dwarf::DW_FORM_string);
454 EmitAbbrev(MCOS, dwarf::DW_AT_language, dwarf::DW_FORM_data2);
455 EmitAbbrev(MCOS, 0, 0);
457 // DW_TAG_label DIE abbrev (2).
458 MCOS->EmitULEB128IntValue(2);
459 MCOS->EmitULEB128IntValue(dwarf::DW_TAG_label);
460 MCOS->EmitIntValue(dwarf::DW_CHILDREN_yes, 1);
461 EmitAbbrev(MCOS, dwarf::DW_AT_name, dwarf::DW_FORM_string);
462 EmitAbbrev(MCOS, dwarf::DW_AT_decl_file, dwarf::DW_FORM_data4);
463 EmitAbbrev(MCOS, dwarf::DW_AT_decl_line, dwarf::DW_FORM_data4);
464 EmitAbbrev(MCOS, dwarf::DW_AT_low_pc, dwarf::DW_FORM_addr);
465 EmitAbbrev(MCOS, dwarf::DW_AT_prototyped, dwarf::DW_FORM_flag);
466 EmitAbbrev(MCOS, 0, 0);
468 // DW_TAG_unspecified_parameters DIE abbrev (3).
469 MCOS->EmitULEB128IntValue(3);
470 MCOS->EmitULEB128IntValue(dwarf::DW_TAG_unspecified_parameters);
471 MCOS->EmitIntValue(dwarf::DW_CHILDREN_no, 1);
472 EmitAbbrev(MCOS, 0, 0);
474 // Terminate the abbreviations for this compilation unit.
475 MCOS->EmitIntValue(0, 1);
478 // When generating dwarf for assembly source files this emits the data for
479 // .debug_aranges section. Which contains a header and a table of pairs of
480 // PointerSize'ed values for the address and size of section(s) with line table
481 // entries (just the default .text in our case) and a terminating pair of zeros.
482 static void EmitGenDwarfAranges(MCStreamer *MCOS) {
483 MCContext &context = MCOS->getContext();
485 // Create a symbol at the end of the section that we are creating the dwarf
486 // debugging info to use later in here as part of the expression to calculate
487 // the size of the section for the table.
488 MCOS->SwitchSection(context.getGenDwarfSection());
489 MCSymbol *SectionEndSym = context.CreateTempSymbol();
490 MCOS->EmitLabel(SectionEndSym);
491 context.setGenDwarfSectionEndSym(SectionEndSym);
493 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfARangesSection());
495 // This will be the length of the .debug_aranges section, first account for
496 // the size of each item in the header (see below where we emit these items).
497 int Length = 4 + 2 + 4 + 1 + 1;
499 // Figure the padding after the header before the table of address and size
500 // pairs who's values are PointerSize'ed.
501 const MCAsmInfo &asmInfo = context.getAsmInfo();
502 int AddrSize = asmInfo.getPointerSize();
503 int Pad = 2 * AddrSize - (Length & (2 * AddrSize - 1));
504 if (Pad == 2 * AddrSize)
508 // Add the size of the pair of PointerSize'ed values for the address and size
509 // of the one default .text section we have in the table.
510 Length += 2 * AddrSize;
511 // And the pair of terminating zeros.
512 Length += 2 * AddrSize;
515 // Emit the header for this section.
516 // The 4 byte length not including the 4 byte value for the length.
517 MCOS->EmitIntValue(Length - 4, 4);
518 // The 2 byte version, which is 2.
519 MCOS->EmitIntValue(2, 2);
520 // The 4 byte offset to the compile unit in the .debug_info from the start
521 // of the .debug_info, it is at the start of that section so this is zero.
522 MCOS->EmitIntValue(0, 4);
523 // The 1 byte size of an address.
524 MCOS->EmitIntValue(AddrSize, 1);
525 // The 1 byte size of a segment descriptor, we use a value of zero.
526 MCOS->EmitIntValue(0, 1);
527 // Align the header with the padding if needed, before we put out the table.
528 for(int i = 0; i < Pad; i++)
529 MCOS->EmitIntValue(0, 1);
531 // Now emit the table of pairs of PointerSize'ed values for the section(s)
532 // address and size, in our case just the one default .text section.
533 const MCExpr *Addr = MCSymbolRefExpr::Create(
534 context.getGenDwarfSectionStartSym(), MCSymbolRefExpr::VK_None, context);
535 const MCExpr *Size = MakeStartMinusEndExpr(*MCOS,
536 *context.getGenDwarfSectionStartSym(), *SectionEndSym, 0);
537 MCOS->EmitAbsValue(Addr, AddrSize);
538 MCOS->EmitAbsValue(Size, AddrSize);
540 // And finally the pair of terminating zeros.
541 MCOS->EmitIntValue(0, AddrSize);
542 MCOS->EmitIntValue(0, AddrSize);
545 // When generating dwarf for assembly source files this emits the data for
546 // .debug_info section which contains three parts. The header, the compile_unit
547 // DIE and a list of label DIEs.
548 static void EmitGenDwarfInfo(MCStreamer *MCOS) {
549 MCContext &context = MCOS->getContext();
551 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfInfoSection());
553 // Create a symbol at the start and end of this section used in here for the
554 // expression to calculate the length in the header.
555 MCSymbol *InfoStart = context.CreateTempSymbol();
556 MCOS->EmitLabel(InfoStart);
557 MCSymbol *InfoEnd = context.CreateTempSymbol();
559 // First part: the header.
561 // The 4 byte total length of the information for this compilation unit, not
562 // including these 4 bytes.
563 const MCExpr *Length = MakeStartMinusEndExpr(*MCOS, *InfoStart, *InfoEnd, 4);
564 MCOS->EmitAbsValue(Length, 4);
566 // The 2 byte DWARF version, which is 2.
567 MCOS->EmitIntValue(2, 2);
569 // The 4 byte offset to the debug abbrevs from the start of the .debug_abbrev,
570 // it is at the start of that section so this is zero.
571 MCOS->EmitIntValue(0, 4);
573 const MCAsmInfo &asmInfo = context.getAsmInfo();
574 int AddrSize = asmInfo.getPointerSize();
575 // The 1 byte size of an address.
576 MCOS->EmitIntValue(AddrSize, 1);
578 // Second part: the compile_unit DIE.
580 // The DW_TAG_compile_unit DIE abbrev (1).
581 MCOS->EmitULEB128IntValue(1);
583 // DW_AT_stmt_list, a 4 byte offset from the start of the .debug_line section,
584 // which is at the start of that section so this is zero.
585 MCOS->EmitIntValue(0, 4);
587 // AT_low_pc, the first address of the default .text section.
588 const MCExpr *Start = MCSymbolRefExpr::Create(
589 context.getGenDwarfSectionStartSym(), MCSymbolRefExpr::VK_None, context);
590 MCOS->EmitAbsValue(Start, AddrSize);
592 // AT_high_pc, the last address of the default .text section.
593 const MCExpr *End = MCSymbolRefExpr::Create(
594 context.getGenDwarfSectionEndSym(), MCSymbolRefExpr::VK_None, context);
595 MCOS->EmitAbsValue(End, AddrSize);
597 // AT_name, the name of the source file. Reconstruct from the first directory
598 // and file table entries.
599 const std::vector<StringRef> &MCDwarfDirs =
600 context.getMCDwarfDirs();
601 if (MCDwarfDirs.size() > 0) {
602 MCOS->EmitBytes(MCDwarfDirs[0], 0);
603 MCOS->EmitBytes("/", 0);
605 const std::vector<MCDwarfFile *> &MCDwarfFiles =
606 MCOS->getContext().getMCDwarfFiles();
607 MCOS->EmitBytes(MCDwarfFiles[1]->getName(), 0);
608 MCOS->EmitIntValue(0, 1); // NULL byte to terminate the string.
610 // AT_comp_dir, the working directory the assembly was done in.
611 llvm::sys::Path CWD = llvm::sys::Path::GetCurrentDirectory();
612 MCOS->EmitBytes(StringRef(CWD.c_str()), 0);
613 MCOS->EmitIntValue(0, 1); // NULL byte to terminate the string.
615 // AT_APPLE_flags, the command line arguments of the assembler tool.
616 StringRef DwarfDebugFlags = context.getDwarfDebugFlags();
617 if (!DwarfDebugFlags.empty()){
618 MCOS->EmitBytes(DwarfDebugFlags, 0);
619 MCOS->EmitIntValue(0, 1); // NULL byte to terminate the string.
622 // AT_producer, the version of the assembler tool.
623 MCOS->EmitBytes(StringRef("llvm-mc (based on LLVM "), 0);
624 MCOS->EmitBytes(StringRef(PACKAGE_VERSION), 0);
625 MCOS->EmitBytes(StringRef(")"), 0);
626 MCOS->EmitIntValue(0, 1); // NULL byte to terminate the string.
628 // AT_language, a 4 byte value. We use DW_LANG_Mips_Assembler as the dwarf2
629 // draft has no standard code for assembler.
630 MCOS->EmitIntValue(dwarf::DW_LANG_Mips_Assembler, 2);
632 // Third part: the list of label DIEs.
634 // Loop on saved info for dwarf labels and create the DIEs for them.
635 const std::vector<const MCGenDwarfLabelEntry *> &Entries =
636 MCOS->getContext().getMCGenDwarfLabelEntries();
637 for (std::vector<const MCGenDwarfLabelEntry *>::const_iterator it =
638 Entries.begin(), ie = Entries.end(); it != ie;
640 const MCGenDwarfLabelEntry *Entry = *it;
642 // The DW_TAG_label DIE abbrev (2).
643 MCOS->EmitULEB128IntValue(2);
645 // AT_name, of the label without any leading underbar.
646 MCOS->EmitBytes(Entry->getName(), 0);
647 MCOS->EmitIntValue(0, 1); // NULL byte to terminate the string.
649 // AT_decl_file, index into the file table.
650 MCOS->EmitIntValue(Entry->getFileNumber(), 4);
652 // AT_decl_line, source line number.
653 MCOS->EmitIntValue(Entry->getLineNumber(), 4);
655 // AT_low_pc, start address of the label.
656 const MCExpr *AT_low_pc = MCSymbolRefExpr::Create(Entry->getLabel(),
657 MCSymbolRefExpr::VK_None, context);
658 MCOS->EmitAbsValue(AT_low_pc, AddrSize);
660 // DW_AT_prototyped, a one byte flag value of 0 saying we have no prototype.
661 MCOS->EmitIntValue(0, 1);
663 // The DW_TAG_unspecified_parameters DIE abbrev (3).
664 MCOS->EmitULEB128IntValue(3);
666 // Add the NULL DIE terminating the DW_TAG_unspecified_parameters DIE's.
667 MCOS->EmitIntValue(0, 1);
669 // Deallocate the MCGenDwarfLabelEntry classes that saved away the info
670 // for the dwarf labels.
671 for (std::vector<const MCGenDwarfLabelEntry *>::const_iterator it =
672 Entries.begin(), ie = Entries.end(); it != ie;
674 const MCGenDwarfLabelEntry *Entry = *it;
678 // Add the NULL DIE terminating the Compile Unit DIE's.
679 MCOS->EmitIntValue(0, 1);
681 // Now set the value of the symbol at the end of the info section.
682 MCOS->EmitLabel(InfoEnd);
686 // When generating dwarf for assembly source files this emits the Dwarf
689 void MCGenDwarfInfo::Emit(MCStreamer *MCOS) {
690 // Create the dwarf sections in this order (.debug_line already created).
691 MCContext &context = MCOS->getContext();
692 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfInfoSection());
693 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfAbbrevSection());
694 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfARangesSection());
696 // If there are no line table entries then do not emit any section contents.
697 if (context.getMCLineSections().empty())
700 // Output the data for .debug_aranges section.
701 EmitGenDwarfAranges(MCOS);
703 // Output the data for .debug_abbrev section.
704 EmitGenDwarfAbbrev(MCOS);
706 // Output the data for .debug_info section.
707 EmitGenDwarfInfo(MCOS);
711 // When generating dwarf for assembly source files this is called when symbol
712 // for a label is created. If this symbol is not a temporary and is in the
713 // section that dwarf is being generated for, save the needed info to create
716 void MCGenDwarfLabelEntry::Make(MCSymbol *Symbol, MCStreamer *MCOS,
717 SourceMgr &SrcMgr, SMLoc &Loc) {
718 // We won't create dwarf label's for temporary symbols or symbols not in
720 if (Symbol->isTemporary())
722 MCContext &context = MCOS->getContext();
723 if (context.getGenDwarfSection() != MCOS->getCurrentSection())
726 // The dwarf label's name does not have the symbol name's leading
728 StringRef Name = Symbol->getName();
729 if (Name.startswith("_"))
730 Name = Name.substr(1, Name.size()-1);
732 // Get the dwarf file number to be used for the dwarf label.
733 unsigned FileNumber = context.getGenDwarfFileNumber();
735 // Finding the line number is the expensive part which is why we just don't
736 // pass it in as for some symbols we won't create a dwarf label.
737 int CurBuffer = SrcMgr.FindBufferContainingLoc(Loc);
738 unsigned LineNumber = SrcMgr.FindLineNumber(Loc, CurBuffer);
740 // We create a temporary symbol for use for the AT_high_pc and AT_low_pc
741 // values so that they don't have things like an ARM thumb bit from the
742 // original symbol. So when used they won't get a low bit set after
744 MCSymbol *Label = context.CreateTempSymbol();
745 MCOS->EmitLabel(Label);
747 // Create and entry for the info and add it to the other entries.
748 MCGenDwarfLabelEntry *Entry =
749 new MCGenDwarfLabelEntry(Name, FileNumber, LineNumber, Label);
750 MCOS->getContext().addMCGenDwarfLabelEntry(Entry);
753 static int getDataAlignmentFactor(MCStreamer &streamer) {
754 MCContext &context = streamer.getContext();
755 const MCAsmInfo &asmInfo = context.getAsmInfo();
756 int size = asmInfo.getPointerSize();
757 if (asmInfo.isStackGrowthDirectionUp())
763 static unsigned getSizeForEncoding(MCStreamer &streamer,
764 unsigned symbolEncoding) {
765 MCContext &context = streamer.getContext();
766 unsigned format = symbolEncoding & 0x0f;
769 assert(0 && "Unknown Encoding");
770 case dwarf::DW_EH_PE_absptr:
771 case dwarf::DW_EH_PE_signed:
772 return context.getAsmInfo().getPointerSize();
773 case dwarf::DW_EH_PE_udata2:
774 case dwarf::DW_EH_PE_sdata2:
776 case dwarf::DW_EH_PE_udata4:
777 case dwarf::DW_EH_PE_sdata4:
779 case dwarf::DW_EH_PE_udata8:
780 case dwarf::DW_EH_PE_sdata8:
785 static void EmitSymbol(MCStreamer &streamer, const MCSymbol &symbol,
786 unsigned symbolEncoding, const char *comment = 0) {
787 MCContext &context = streamer.getContext();
788 const MCAsmInfo &asmInfo = context.getAsmInfo();
789 const MCExpr *v = asmInfo.getExprForFDESymbol(&symbol,
792 unsigned size = getSizeForEncoding(streamer, symbolEncoding);
793 if (streamer.isVerboseAsm() && comment) streamer.AddComment(comment);
794 streamer.EmitAbsValue(v, size);
797 static void EmitPersonality(MCStreamer &streamer, const MCSymbol &symbol,
798 unsigned symbolEncoding) {
799 MCContext &context = streamer.getContext();
800 const MCAsmInfo &asmInfo = context.getAsmInfo();
801 const MCExpr *v = asmInfo.getExprForPersonalitySymbol(&symbol,
804 unsigned size = getSizeForEncoding(streamer, symbolEncoding);
805 streamer.EmitValue(v, size);
808 static const MachineLocation TranslateMachineLocation(
809 const MCRegisterInfo &MRI,
810 const MachineLocation &Loc) {
811 unsigned Reg = Loc.getReg() == MachineLocation::VirtualFP ?
812 MachineLocation::VirtualFP :
813 unsigned(MRI.getDwarfRegNum(Loc.getReg(), true));
814 const MachineLocation &NewLoc = Loc.isReg() ?
815 MachineLocation(Reg) : MachineLocation(Reg, Loc.getOffset());
820 class FrameEmitterImpl {
825 const MCSymbol *SectionStart;
827 FrameEmitterImpl(bool usingCFI, bool isEH)
828 : CFAOffset(0), CIENum(0), UsingCFI(usingCFI), IsEH(isEH),
831 void setSectionStart(const MCSymbol *Label) { SectionStart = Label; }
833 /// EmitCompactUnwind - Emit the unwind information in a compact way. If
834 /// we're successful, return 'true'. Otherwise, return 'false' and it will
835 /// emit the normal CIE and FDE.
836 bool EmitCompactUnwind(MCStreamer &streamer,
837 const MCDwarfFrameInfo &frame);
839 const MCSymbol &EmitCIE(MCStreamer &streamer,
840 const MCSymbol *personality,
841 unsigned personalityEncoding,
842 const MCSymbol *lsda,
843 unsigned lsdaEncoding);
844 MCSymbol *EmitFDE(MCStreamer &streamer,
845 const MCSymbol &cieStart,
846 const MCDwarfFrameInfo &frame);
847 void EmitCFIInstructions(MCStreamer &streamer,
848 const std::vector<MCCFIInstruction> &Instrs,
849 MCSymbol *BaseLabel);
850 void EmitCFIInstruction(MCStreamer &Streamer,
851 const MCCFIInstruction &Instr);
854 } // end anonymous namespace
856 static void EmitEncodingByte(MCStreamer &Streamer, unsigned Encoding,
858 if (Streamer.isVerboseAsm()) {
859 const char *EncStr = 0;
861 default: EncStr = "<unknown encoding>";
862 case dwarf::DW_EH_PE_absptr: EncStr = "absptr";
863 case dwarf::DW_EH_PE_omit: EncStr = "omit";
864 case dwarf::DW_EH_PE_pcrel: EncStr = "pcrel";
865 case dwarf::DW_EH_PE_udata4: EncStr = "udata4";
866 case dwarf::DW_EH_PE_udata8: EncStr = "udata8";
867 case dwarf::DW_EH_PE_sdata4: EncStr = "sdata4";
868 case dwarf::DW_EH_PE_sdata8: EncStr = "sdata8";
869 case dwarf::DW_EH_PE_pcrel |dwarf::DW_EH_PE_udata4: EncStr = "pcrel udata4";
870 case dwarf::DW_EH_PE_pcrel |dwarf::DW_EH_PE_sdata4: EncStr = "pcrel sdata4";
871 case dwarf::DW_EH_PE_pcrel |dwarf::DW_EH_PE_udata8: EncStr = "pcrel udata8";
872 case dwarf::DW_EH_PE_pcrel |dwarf::DW_EH_PE_sdata8: EncStr = "pcrel sdata8";
873 case dwarf::DW_EH_PE_indirect |dwarf::DW_EH_PE_pcrel|dwarf::DW_EH_PE_udata4:
874 EncStr = "indirect pcrel udata4";
875 case dwarf::DW_EH_PE_indirect |dwarf::DW_EH_PE_pcrel|dwarf::DW_EH_PE_sdata4:
876 EncStr = "indirect pcrel sdata4";
877 case dwarf::DW_EH_PE_indirect |dwarf::DW_EH_PE_pcrel|dwarf::DW_EH_PE_udata8:
878 EncStr = "indirect pcrel udata8";
879 case dwarf::DW_EH_PE_indirect |dwarf::DW_EH_PE_pcrel|dwarf::DW_EH_PE_sdata8:
880 EncStr = "indirect pcrel sdata8";
883 Streamer.AddComment(Twine(Prefix) + " = " + EncStr);
886 Streamer.EmitIntValue(Encoding, 1);
889 void FrameEmitterImpl::EmitCFIInstruction(MCStreamer &Streamer,
890 const MCCFIInstruction &Instr) {
891 int dataAlignmentFactor = getDataAlignmentFactor(Streamer);
892 bool VerboseAsm = Streamer.isVerboseAsm();
894 switch (Instr.getOperation()) {
895 case MCCFIInstruction::Move:
896 case MCCFIInstruction::RelMove: {
897 const MachineLocation &Dst = Instr.getDestination();
898 const MachineLocation &Src = Instr.getSource();
899 const bool IsRelative = Instr.getOperation() == MCCFIInstruction::RelMove;
902 if (Dst.isReg() && Dst.getReg() == MachineLocation::VirtualFP) {
903 if (Src.getReg() == MachineLocation::VirtualFP) {
904 if (VerboseAsm) Streamer.AddComment("DW_CFA_def_cfa_offset");
905 Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa_offset, 1);
907 if (VerboseAsm) Streamer.AddComment("DW_CFA_def_cfa");
908 Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa, 1);
909 if (VerboseAsm) Streamer.AddComment(Twine("Reg ") +
910 Twine(Src.getReg()));
911 Streamer.EmitULEB128IntValue(Src.getReg());
915 CFAOffset += Src.getOffset();
917 CFAOffset = -Src.getOffset();
919 if (VerboseAsm) Streamer.AddComment(Twine("Offset " + Twine(CFAOffset)));
920 Streamer.EmitULEB128IntValue(CFAOffset);
924 if (Src.isReg() && Src.getReg() == MachineLocation::VirtualFP) {
925 assert(Dst.isReg() && "Machine move not supported yet.");
926 if (VerboseAsm) Streamer.AddComment("DW_CFA_def_cfa_register");
927 Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa_register, 1);
928 if (VerboseAsm) Streamer.AddComment(Twine("Reg ") + Twine(Dst.getReg()));
929 Streamer.EmitULEB128IntValue(Dst.getReg());
933 unsigned Reg = Src.getReg();
934 int Offset = Dst.getOffset();
937 Offset = Offset / dataAlignmentFactor;
940 if (VerboseAsm) Streamer.AddComment("DW_CFA_offset_extended_sf");
941 Streamer.EmitIntValue(dwarf::DW_CFA_offset_extended_sf, 1);
942 if (VerboseAsm) Streamer.AddComment(Twine("Reg ") + Twine(Reg));
943 Streamer.EmitULEB128IntValue(Reg);
944 if (VerboseAsm) Streamer.AddComment(Twine("Offset ") + Twine(Offset));
945 Streamer.EmitSLEB128IntValue(Offset);
946 } else if (Reg < 64) {
947 if (VerboseAsm) Streamer.AddComment(Twine("DW_CFA_offset + Reg(") +
949 Streamer.EmitIntValue(dwarf::DW_CFA_offset + Reg, 1);
950 if (VerboseAsm) Streamer.AddComment(Twine("Offset ") + Twine(Offset));
951 Streamer.EmitULEB128IntValue(Offset);
953 if (VerboseAsm) Streamer.AddComment("DW_CFA_offset_extended");
954 Streamer.EmitIntValue(dwarf::DW_CFA_offset_extended, 1);
955 if (VerboseAsm) Streamer.AddComment(Twine("Reg ") + Twine(Reg));
956 Streamer.EmitULEB128IntValue(Reg);
957 if (VerboseAsm) Streamer.AddComment(Twine("Offset ") + Twine(Offset));
958 Streamer.EmitULEB128IntValue(Offset);
962 case MCCFIInstruction::RememberState:
963 if (VerboseAsm) Streamer.AddComment("DW_CFA_remember_state");
964 Streamer.EmitIntValue(dwarf::DW_CFA_remember_state, 1);
966 case MCCFIInstruction::RestoreState:
967 if (VerboseAsm) Streamer.AddComment("DW_CFA_restore_state");
968 Streamer.EmitIntValue(dwarf::DW_CFA_restore_state, 1);
970 case MCCFIInstruction::SameValue: {
971 unsigned Reg = Instr.getDestination().getReg();
972 if (VerboseAsm) Streamer.AddComment("DW_CFA_same_value");
973 Streamer.EmitIntValue(dwarf::DW_CFA_same_value, 1);
974 if (VerboseAsm) Streamer.AddComment(Twine("Reg ") + Twine(Reg));
975 Streamer.EmitULEB128IntValue(Reg);
978 case MCCFIInstruction::Restore: {
979 unsigned Reg = Instr.getDestination().getReg();
981 Streamer.AddComment("DW_CFA_restore");
982 Streamer.AddComment(Twine("Reg ") + Twine(Reg));
984 Streamer.EmitIntValue(dwarf::DW_CFA_restore | Reg, 1);
987 case MCCFIInstruction::Escape:
988 if (VerboseAsm) Streamer.AddComment("Escape bytes");
989 Streamer.EmitBytes(Instr.getValues(), 0);
992 llvm_unreachable("Unhandled case in switch");
995 /// EmitFrameMoves - Emit frame instructions to describe the layout of the
997 void FrameEmitterImpl::EmitCFIInstructions(MCStreamer &streamer,
998 const std::vector<MCCFIInstruction> &Instrs,
999 MCSymbol *BaseLabel) {
1000 for (unsigned i = 0, N = Instrs.size(); i < N; ++i) {
1001 const MCCFIInstruction &Instr = Instrs[i];
1002 MCSymbol *Label = Instr.getLabel();
1003 // Throw out move if the label is invalid.
1004 if (Label && !Label->isDefined()) continue; // Not emitted, in dead code.
1006 // Advance row if new location.
1007 if (BaseLabel && Label) {
1008 MCSymbol *ThisSym = Label;
1009 if (ThisSym != BaseLabel) {
1010 if (streamer.isVerboseAsm()) streamer.AddComment("DW_CFA_advance_loc4");
1011 streamer.EmitDwarfAdvanceFrameAddr(BaseLabel, ThisSym);
1012 BaseLabel = ThisSym;
1016 EmitCFIInstruction(streamer, Instr);
1020 /// EmitCompactUnwind - Emit the unwind information in a compact way. If we're
1021 /// successful, return 'true'. Otherwise, return 'false' and it will emit the
1022 /// normal CIE and FDE.
1023 bool FrameEmitterImpl::EmitCompactUnwind(MCStreamer &Streamer,
1024 const MCDwarfFrameInfo &Frame) {
1025 MCContext &Context = Streamer.getContext();
1026 const MCObjectFileInfo *MOFI = Context.getObjectFileInfo();
1027 bool VerboseAsm = Streamer.isVerboseAsm();
1029 // range-start range-length compact-unwind-enc personality-func lsda
1030 // _foo LfooEnd-_foo 0x00000023 0 0
1031 // _bar LbarEnd-_bar 0x00000025 __gxx_personality except_tab1
1033 // .section __LD,__compact_unwind,regular,debug
1035 // # compact unwind for _foo
1037 // .set L1,LfooEnd-_foo
1043 // # compact unwind for _bar
1045 // .set L2,LbarEnd-_bar
1048 // .quad __gxx_personality
1049 // .quad except_tab1
1051 uint32_t Encoding = Frame.CompactUnwindEncoding;
1052 if (!Encoding) return false;
1054 // The encoding needs to know we have an LSDA.
1056 Encoding |= 0x40000000;
1058 Streamer.SwitchSection(MOFI->getCompactUnwindSection());
1061 unsigned FDEEncoding = MOFI->getFDEEncoding(UsingCFI);
1062 unsigned Size = getSizeForEncoding(Streamer, FDEEncoding);
1063 if (VerboseAsm) Streamer.AddComment("Range Start");
1064 Streamer.EmitSymbolValue(Frame.Function, Size);
1067 const MCExpr *Range = MakeStartMinusEndExpr(Streamer, *Frame.Begin,
1069 if (VerboseAsm) Streamer.AddComment("Range Length");
1070 Streamer.EmitAbsValue(Range, 4);
1073 Size = getSizeForEncoding(Streamer, dwarf::DW_EH_PE_udata4);
1074 if (VerboseAsm) Streamer.AddComment("Compact Unwind Encoding: 0x" +
1075 Twine::utohexstr(Encoding));
1076 Streamer.EmitIntValue(Encoding, Size);
1079 // Personality Function
1080 Size = getSizeForEncoding(Streamer, dwarf::DW_EH_PE_absptr);
1081 if (VerboseAsm) Streamer.AddComment("Personality Function");
1082 if (Frame.Personality)
1083 Streamer.EmitSymbolValue(Frame.Personality, Size);
1085 Streamer.EmitIntValue(0, Size); // No personality fn
1088 Size = getSizeForEncoding(Streamer, Frame.LsdaEncoding);
1089 if (VerboseAsm) Streamer.AddComment("LSDA");
1091 Streamer.EmitSymbolValue(Frame.Lsda, Size);
1093 Streamer.EmitIntValue(0, Size); // No LSDA
1098 const MCSymbol &FrameEmitterImpl::EmitCIE(MCStreamer &streamer,
1099 const MCSymbol *personality,
1100 unsigned personalityEncoding,
1101 const MCSymbol *lsda,
1102 unsigned lsdaEncoding) {
1103 MCContext &context = streamer.getContext();
1104 const MCRegisterInfo &MRI = context.getRegisterInfo();
1105 const MCObjectFileInfo *MOFI = context.getObjectFileInfo();
1106 bool verboseAsm = streamer.isVerboseAsm();
1108 MCSymbol *sectionStart;
1109 if (MOFI->isFunctionEHFrameSymbolPrivate() || !IsEH)
1110 sectionStart = context.CreateTempSymbol();
1112 sectionStart = context.GetOrCreateSymbol(Twine("EH_frame") + Twine(CIENum));
1114 streamer.EmitLabel(sectionStart);
1117 MCSymbol *sectionEnd = context.CreateTempSymbol();
1120 const MCExpr *Length = MakeStartMinusEndExpr(streamer, *sectionStart,
1122 if (verboseAsm) streamer.AddComment("CIE Length");
1123 streamer.EmitAbsValue(Length, 4);
1126 unsigned CIE_ID = IsEH ? 0 : -1;
1127 if (verboseAsm) streamer.AddComment("CIE ID Tag");
1128 streamer.EmitIntValue(CIE_ID, 4);
1131 if (verboseAsm) streamer.AddComment("DW_CIE_VERSION");
1132 streamer.EmitIntValue(dwarf::DW_CIE_VERSION, 1);
1134 // Augmentation String
1135 SmallString<8> Augmentation;
1137 if (verboseAsm) streamer.AddComment("CIE Augmentation");
1138 Augmentation += "z";
1140 Augmentation += "P";
1142 Augmentation += "L";
1143 Augmentation += "R";
1144 streamer.EmitBytes(Augmentation.str(), 0);
1146 streamer.EmitIntValue(0, 1);
1148 // Code Alignment Factor
1149 if (verboseAsm) streamer.AddComment("CIE Code Alignment Factor");
1150 streamer.EmitULEB128IntValue(1);
1152 // Data Alignment Factor
1153 if (verboseAsm) streamer.AddComment("CIE Data Alignment Factor");
1154 streamer.EmitSLEB128IntValue(getDataAlignmentFactor(streamer));
1156 // Return Address Register
1157 if (verboseAsm) streamer.AddComment("CIE Return Address Column");
1158 streamer.EmitULEB128IntValue(MRI.getDwarfRegNum(MRI.getRARegister(), true));
1160 // Augmentation Data Length (optional)
1162 unsigned augmentationLength = 0;
1165 // Personality Encoding
1166 augmentationLength += 1;
1168 augmentationLength += getSizeForEncoding(streamer, personalityEncoding);
1171 augmentationLength += 1;
1172 // Encoding of the FDE pointers
1173 augmentationLength += 1;
1175 if (verboseAsm) streamer.AddComment("Augmentation Size");
1176 streamer.EmitULEB128IntValue(augmentationLength);
1178 // Augmentation Data (optional)
1180 // Personality Encoding
1181 EmitEncodingByte(streamer, personalityEncoding,
1182 "Personality Encoding");
1184 if (verboseAsm) streamer.AddComment("Personality");
1185 EmitPersonality(streamer, *personality, personalityEncoding);
1189 EmitEncodingByte(streamer, lsdaEncoding, "LSDA Encoding");
1191 // Encoding of the FDE pointers
1192 EmitEncodingByte(streamer, MOFI->getFDEEncoding(UsingCFI),
1196 // Initial Instructions
1198 const MCAsmInfo &MAI = context.getAsmInfo();
1199 const std::vector<MachineMove> &Moves = MAI.getInitialFrameState();
1200 std::vector<MCCFIInstruction> Instructions;
1202 for (int i = 0, n = Moves.size(); i != n; ++i) {
1203 MCSymbol *Label = Moves[i].getLabel();
1204 const MachineLocation &Dst =
1205 TranslateMachineLocation(MRI, Moves[i].getDestination());
1206 const MachineLocation &Src =
1207 TranslateMachineLocation(MRI, Moves[i].getSource());
1208 MCCFIInstruction Inst(Label, Dst, Src);
1209 Instructions.push_back(Inst);
1212 EmitCFIInstructions(streamer, Instructions, NULL);
1215 streamer.EmitValueToAlignment(IsEH
1216 ? 4 : context.getAsmInfo().getPointerSize());
1218 streamer.EmitLabel(sectionEnd);
1219 return *sectionStart;
1222 MCSymbol *FrameEmitterImpl::EmitFDE(MCStreamer &streamer,
1223 const MCSymbol &cieStart,
1224 const MCDwarfFrameInfo &frame) {
1225 MCContext &context = streamer.getContext();
1226 MCSymbol *fdeStart = context.CreateTempSymbol();
1227 MCSymbol *fdeEnd = context.CreateTempSymbol();
1228 const MCObjectFileInfo *MOFI = context.getObjectFileInfo();
1229 bool verboseAsm = streamer.isVerboseAsm();
1231 if (IsEH && frame.Function && !MOFI->isFunctionEHFrameSymbolPrivate()) {
1233 context.GetOrCreateSymbol(frame.Function->getName() + Twine(".eh"));
1234 streamer.EmitEHSymAttributes(frame.Function, EHSym);
1235 streamer.EmitLabel(EHSym);
1239 const MCExpr *Length = MakeStartMinusEndExpr(streamer, *fdeStart, *fdeEnd, 0);
1240 if (verboseAsm) streamer.AddComment("FDE Length");
1241 streamer.EmitAbsValue(Length, 4);
1243 streamer.EmitLabel(fdeStart);
1246 const MCAsmInfo &asmInfo = context.getAsmInfo();
1248 const MCExpr *offset = MakeStartMinusEndExpr(streamer, cieStart, *fdeStart,
1250 if (verboseAsm) streamer.AddComment("FDE CIE Offset");
1251 streamer.EmitAbsValue(offset, 4);
1252 } else if (!asmInfo.doesDwarfRequireRelocationForSectionOffset()) {
1253 const MCExpr *offset = MakeStartMinusEndExpr(streamer, *SectionStart,
1255 streamer.EmitAbsValue(offset, 4);
1257 streamer.EmitSymbolValue(&cieStart, 4);
1260 unsigned fdeEncoding = MOFI->getFDEEncoding(UsingCFI);
1261 unsigned size = getSizeForEncoding(streamer, fdeEncoding);
1264 unsigned PCBeginEncoding = IsEH ? fdeEncoding :
1265 (unsigned)dwarf::DW_EH_PE_absptr;
1266 unsigned PCBeginSize = getSizeForEncoding(streamer, PCBeginEncoding);
1267 EmitSymbol(streamer, *frame.Begin, PCBeginEncoding, "FDE initial location");
1270 const MCExpr *Range = MakeStartMinusEndExpr(streamer, *frame.Begin,
1272 if (verboseAsm) streamer.AddComment("FDE address range");
1273 streamer.EmitAbsValue(Range, size);
1276 // Augmentation Data Length
1277 unsigned augmentationLength = 0;
1280 augmentationLength += getSizeForEncoding(streamer, frame.LsdaEncoding);
1282 if (verboseAsm) streamer.AddComment("Augmentation size");
1283 streamer.EmitULEB128IntValue(augmentationLength);
1285 // Augmentation Data
1287 EmitSymbol(streamer, *frame.Lsda, frame.LsdaEncoding,
1288 "Language Specific Data Area");
1291 // Call Frame Instructions
1293 EmitCFIInstructions(streamer, frame.Instructions, frame.Begin);
1296 streamer.EmitValueToAlignment(PCBeginSize);
1303 static const CIEKey getEmptyKey() { return CIEKey(0, 0, -1); }
1304 static const CIEKey getTombstoneKey() { return CIEKey(0, -1, 0); }
1306 CIEKey(const MCSymbol* Personality_, unsigned PersonalityEncoding_,
1307 unsigned LsdaEncoding_) : Personality(Personality_),
1308 PersonalityEncoding(PersonalityEncoding_),
1309 LsdaEncoding(LsdaEncoding_) {
1311 const MCSymbol* Personality;
1312 unsigned PersonalityEncoding;
1313 unsigned LsdaEncoding;
1319 struct DenseMapInfo<CIEKey> {
1320 static CIEKey getEmptyKey() {
1321 return CIEKey::getEmptyKey();
1323 static CIEKey getTombstoneKey() {
1324 return CIEKey::getTombstoneKey();
1326 static unsigned getHashValue(const CIEKey &Key) {
1327 FoldingSetNodeID ID;
1328 ID.AddPointer(Key.Personality);
1329 ID.AddInteger(Key.PersonalityEncoding);
1330 ID.AddInteger(Key.LsdaEncoding);
1331 return ID.ComputeHash();
1333 static bool isEqual(const CIEKey &LHS,
1334 const CIEKey &RHS) {
1335 return LHS.Personality == RHS.Personality &&
1336 LHS.PersonalityEncoding == RHS.PersonalityEncoding &&
1337 LHS.LsdaEncoding == RHS.LsdaEncoding;
1342 void MCDwarfFrameEmitter::Emit(MCStreamer &Streamer,
1345 MCContext &Context = Streamer.getContext();
1346 MCObjectFileInfo *MOFI =
1347 const_cast<MCObjectFileInfo*>(Context.getObjectFileInfo());
1348 FrameEmitterImpl Emitter(UsingCFI, IsEH);
1349 ArrayRef<MCDwarfFrameInfo> FrameArray = Streamer.getFrameInfos();
1351 // Emit the compact unwind info if available.
1352 if (IsEH && MOFI->getCompactUnwindSection())
1353 for (unsigned i = 0, n = Streamer.getNumFrameInfos(); i < n; ++i) {
1354 const MCDwarfFrameInfo &Frame = Streamer.getFrameInfo(i);
1355 if (Frame.CompactUnwindEncoding)
1356 Emitter.EmitCompactUnwind(Streamer, Frame);
1359 const MCSection &Section = IsEH ? *MOFI->getEHFrameSection() :
1360 *MOFI->getDwarfFrameSection();
1361 Streamer.SwitchSection(&Section);
1362 MCSymbol *SectionStart = Context.CreateTempSymbol();
1363 Streamer.EmitLabel(SectionStart);
1364 Emitter.setSectionStart(SectionStart);
1366 MCSymbol *FDEEnd = NULL;
1367 DenseMap<CIEKey, const MCSymbol*> CIEStarts;
1369 const MCSymbol *DummyDebugKey = NULL;
1370 for (unsigned i = 0, n = FrameArray.size(); i < n; ++i) {
1371 const MCDwarfFrameInfo &Frame = FrameArray[i];
1372 CIEKey Key(Frame.Personality, Frame.PersonalityEncoding,
1373 Frame.LsdaEncoding);
1374 const MCSymbol *&CIEStart = IsEH ? CIEStarts[Key] : DummyDebugKey;
1376 CIEStart = &Emitter.EmitCIE(Streamer, Frame.Personality,
1377 Frame.PersonalityEncoding, Frame.Lsda,
1378 Frame.LsdaEncoding);
1380 FDEEnd = Emitter.EmitFDE(Streamer, *CIEStart, Frame);
1383 Streamer.EmitLabel(FDEEnd);
1386 Streamer.EmitValueToAlignment(Context.getAsmInfo().getPointerSize());
1388 Streamer.EmitLabel(FDEEnd);
1391 void MCDwarfFrameEmitter::EmitAdvanceLoc(MCStreamer &Streamer,
1392 uint64_t AddrDelta) {
1393 SmallString<256> Tmp;
1394 raw_svector_ostream OS(Tmp);
1395 MCDwarfFrameEmitter::EncodeAdvanceLoc(AddrDelta, OS);
1396 Streamer.EmitBytes(OS.str(), /*AddrSpace=*/0);
1399 void MCDwarfFrameEmitter::EncodeAdvanceLoc(uint64_t AddrDelta,
1401 // FIXME: Assumes the code alignment factor is 1.
1402 if (AddrDelta == 0) {
1403 } else if (isUIntN(6, AddrDelta)) {
1404 uint8_t Opcode = dwarf::DW_CFA_advance_loc | AddrDelta;
1406 } else if (isUInt<8>(AddrDelta)) {
1407 OS << uint8_t(dwarf::DW_CFA_advance_loc1);
1408 OS << uint8_t(AddrDelta);
1409 } else if (isUInt<16>(AddrDelta)) {
1410 // FIXME: check what is the correct behavior on a big endian machine.
1411 OS << uint8_t(dwarf::DW_CFA_advance_loc2);
1412 OS << uint8_t( AddrDelta & 0xff);
1413 OS << uint8_t((AddrDelta >> 8) & 0xff);
1415 // FIXME: check what is the correct behavior on a big endian machine.
1416 assert(isUInt<32>(AddrDelta));
1417 OS << uint8_t(dwarf::DW_CFA_advance_loc4);
1418 OS << uint8_t( AddrDelta & 0xff);
1419 OS << uint8_t((AddrDelta >> 8) & 0xff);
1420 OS << uint8_t((AddrDelta >> 16) & 0xff);
1421 OS << uint8_t((AddrDelta >> 24) & 0xff);