1 //===- lib/MC/MCDwarf.cpp - MCDwarf implementation ------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 #include "llvm/MC/MCDwarf.h"
11 #include "llvm/ADT/Hashing.h"
12 #include "llvm/ADT/SmallString.h"
13 #include "llvm/ADT/Twine.h"
14 #include "llvm/Config/config.h"
15 #include "llvm/MC/MCAsmInfo.h"
16 #include "llvm/MC/MCContext.h"
17 #include "llvm/MC/MCExpr.h"
18 #include "llvm/MC/MCObjectFileInfo.h"
19 #include "llvm/MC/MCObjectWriter.h"
20 #include "llvm/MC/MCRegisterInfo.h"
21 #include "llvm/MC/MCStreamer.h"
22 #include "llvm/MC/MCSymbol.h"
23 #include "llvm/Support/Debug.h"
24 #include "llvm/Support/ErrorHandling.h"
25 #include "llvm/Support/LEB128.h"
26 #include "llvm/Support/Path.h"
27 #include "llvm/Support/SourceMgr.h"
28 #include "llvm/Support/raw_ostream.h"
31 // Given a special op, return the address skip amount (in units of
32 // DWARF2_LINE_MIN_INSN_LENGTH.
33 #define SPECIAL_ADDR(op) (((op) - DWARF2_LINE_OPCODE_BASE)/DWARF2_LINE_RANGE)
35 // The maximum address skip amount that can be encoded with a special op.
36 #define MAX_SPECIAL_ADDR_DELTA SPECIAL_ADDR(255)
38 // First special line opcode - leave room for the standard opcodes.
39 // Note: If you want to change this, you'll have to update the
40 // "standard_opcode_lengths" table that is emitted in DwarfFileTable::Emit().
41 #define DWARF2_LINE_OPCODE_BASE 13
43 // Minimum line offset in a special line info. opcode. This value
44 // was chosen to give a reasonable range of values.
45 #define DWARF2_LINE_BASE -5
47 // Range of line offsets in a special line info. opcode.
48 #define DWARF2_LINE_RANGE 14
50 // Define the architecture-dependent minimum instruction length (in bytes).
51 // This value should be rather too small than too big.
52 #define DWARF2_LINE_MIN_INSN_LENGTH 1
54 // Note: when DWARF2_LINE_MIN_INSN_LENGTH == 1 which is the current setting,
55 // this routine is a nop and will be optimized away.
56 static inline uint64_t ScaleAddrDelta(uint64_t AddrDelta) {
57 if (DWARF2_LINE_MIN_INSN_LENGTH == 1)
59 if (AddrDelta % DWARF2_LINE_MIN_INSN_LENGTH != 0) {
60 // TODO: report this error, but really only once.
63 return AddrDelta / DWARF2_LINE_MIN_INSN_LENGTH;
67 // This is called when an instruction is assembled into the specified section
68 // and if there is information from the last .loc directive that has yet to have
69 // a line entry made for it is made.
71 void MCLineEntry::Make(MCStreamer *MCOS, const MCSection *Section) {
72 if (!MCOS->getContext().getDwarfLocSeen())
75 // Create a symbol at in the current section for use in the line entry.
76 MCSymbol *LineSym = MCOS->getContext().CreateTempSymbol();
77 // Set the value of the symbol to use for the MCLineEntry.
78 MCOS->EmitLabel(LineSym);
80 // Get the current .loc info saved in the context.
81 const MCDwarfLoc &DwarfLoc = MCOS->getContext().getCurrentDwarfLoc();
83 // Create a (local) line entry with the symbol and the current .loc info.
84 MCLineEntry LineEntry(LineSym, DwarfLoc);
86 // clear DwarfLocSeen saying the current .loc info is now used.
87 MCOS->getContext().ClearDwarfLocSeen();
89 // Get the MCLineSection for this section, if one does not exist for this
91 const DenseMap<const MCSection *, MCLineSection *> &MCLineSections =
92 MCOS->getContext().getMCLineSections();
93 MCLineSection *LineSection = MCLineSections.lookup(Section);
95 // Create a new MCLineSection. This will be deleted after the dwarf line
96 // table is created using it by iterating through the MCLineSections
98 LineSection = new MCLineSection;
99 // Save a pointer to the new LineSection into the MCLineSections DenseMap.
100 MCOS->getContext().addMCLineSection(Section, LineSection);
103 // Add the line entry to this section's entries.
104 LineSection->addLineEntry(LineEntry,
105 MCOS->getContext().getDwarfCompileUnitID());
109 // This helper routine returns an expression of End - Start + IntVal .
111 static inline const MCExpr *MakeStartMinusEndExpr(const MCStreamer &MCOS,
112 const MCSymbol &Start,
115 MCSymbolRefExpr::VariantKind Variant = MCSymbolRefExpr::VK_None;
117 MCSymbolRefExpr::Create(&End, Variant, MCOS.getContext());
119 MCSymbolRefExpr::Create(&Start, Variant, MCOS.getContext());
121 MCBinaryExpr::Create(MCBinaryExpr::Sub, Res, RHS, MCOS.getContext());
123 MCConstantExpr::Create(IntVal, MCOS.getContext());
125 MCBinaryExpr::Create(MCBinaryExpr::Sub, Res1, Res2, MCOS.getContext());
130 // This emits the Dwarf line table for the specified section from the entries
131 // in the LineSection.
133 static inline void EmitDwarfLineTable(MCStreamer *MCOS,
134 const MCSection *Section,
135 const MCLineSection *LineSection,
137 // This LineSection does not contain any LineEntry for the given Compile Unit.
138 if (!LineSection->containEntriesForID(CUID))
141 unsigned FileNum = 1;
142 unsigned LastLine = 1;
144 unsigned Flags = DWARF2_LINE_DEFAULT_IS_STMT ? DWARF2_FLAG_IS_STMT : 0;
146 MCSymbol *LastLabel = NULL;
148 // Loop through each MCLineEntry and encode the dwarf line number table.
149 for (MCLineSection::const_iterator
150 it = LineSection->getMCLineEntries(CUID).begin(),
151 ie = LineSection->getMCLineEntries(CUID).end(); it != ie; ++it) {
153 if (FileNum != it->getFileNum()) {
154 FileNum = it->getFileNum();
155 MCOS->EmitIntValue(dwarf::DW_LNS_set_file, 1);
156 MCOS->EmitULEB128IntValue(FileNum);
158 if (Column != it->getColumn()) {
159 Column = it->getColumn();
160 MCOS->EmitIntValue(dwarf::DW_LNS_set_column, 1);
161 MCOS->EmitULEB128IntValue(Column);
163 if (Isa != it->getIsa()) {
165 MCOS->EmitIntValue(dwarf::DW_LNS_set_isa, 1);
166 MCOS->EmitULEB128IntValue(Isa);
168 if ((it->getFlags() ^ Flags) & DWARF2_FLAG_IS_STMT) {
169 Flags = it->getFlags();
170 MCOS->EmitIntValue(dwarf::DW_LNS_negate_stmt, 1);
172 if (it->getFlags() & DWARF2_FLAG_BASIC_BLOCK)
173 MCOS->EmitIntValue(dwarf::DW_LNS_set_basic_block, 1);
174 if (it->getFlags() & DWARF2_FLAG_PROLOGUE_END)
175 MCOS->EmitIntValue(dwarf::DW_LNS_set_prologue_end, 1);
176 if (it->getFlags() & DWARF2_FLAG_EPILOGUE_BEGIN)
177 MCOS->EmitIntValue(dwarf::DW_LNS_set_epilogue_begin, 1);
179 int64_t LineDelta = static_cast<int64_t>(it->getLine()) - LastLine;
180 MCSymbol *Label = it->getLabel();
182 // At this point we want to emit/create the sequence to encode the delta in
183 // line numbers and the increment of the address from the previous Label
184 // and the current Label.
185 const MCAsmInfo &asmInfo = MCOS->getContext().getAsmInfo();
186 MCOS->EmitDwarfAdvanceLineAddr(LineDelta, LastLabel, Label,
187 asmInfo.getPointerSize());
189 LastLine = it->getLine();
193 // Emit a DW_LNE_end_sequence for the end of the section.
194 // Using the pointer Section create a temporary label at the end of the
195 // section and use that and the LastLabel to compute the address delta
196 // and use INT64_MAX as the line delta which is the signal that this is
197 // actually a DW_LNE_end_sequence.
199 // Switch to the section to be able to create a symbol at its end.
200 MCOS->SwitchSection(Section);
202 MCContext &context = MCOS->getContext();
203 // Create a symbol at the end of the section.
204 MCSymbol *SectionEnd = context.CreateTempSymbol();
205 // Set the value of the symbol, as we are at the end of the section.
206 MCOS->EmitLabel(SectionEnd);
208 // Switch back the dwarf line section.
209 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfLineSection());
211 const MCAsmInfo &asmInfo = MCOS->getContext().getAsmInfo();
212 MCOS->EmitDwarfAdvanceLineAddr(INT64_MAX, LastLabel, SectionEnd,
213 asmInfo.getPointerSize());
217 // This emits the Dwarf file and the line tables.
219 const MCSymbol *MCDwarfFileTable::Emit(MCStreamer *MCOS) {
220 MCContext &context = MCOS->getContext();
221 // Switch to the section where the table will be emitted into.
222 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfLineSection());
224 const DenseMap<unsigned, MCSymbol *> &MCLineTableSymbols =
225 MCOS->getContext().getMCLineTableSymbols();
226 // CUID and MCLineTableSymbols are set in DwarfDebug, when DwarfDebug does
227 // not exist, CUID will be 0 and MCLineTableSymbols will be empty.
228 // Handle Compile Unit 0, the line table start symbol is the section symbol.
229 const MCSymbol *LineStartSym = EmitCU(MCOS, 0);
230 // Handle the rest of the Compile Units.
231 for (unsigned Is = 1, Ie = MCLineTableSymbols.size(); Is < Ie; Is++)
234 // Now delete the MCLineSections that were created in MCLineEntry::Make()
235 // and used to emit the line table.
236 const DenseMap<const MCSection *, MCLineSection *> &MCLineSections =
237 MCOS->getContext().getMCLineSections();
238 for (DenseMap<const MCSection *, MCLineSection *>::const_iterator it =
239 MCLineSections.begin(), ie = MCLineSections.end(); it != ie;
246 const MCSymbol *MCDwarfFileTable::EmitCU(MCStreamer *MCOS, unsigned CUID) {
247 MCContext &context = MCOS->getContext();
249 // Create a symbol at the beginning of the line table.
250 MCSymbol *LineStartSym = MCOS->getContext().getMCLineTableSymbol(CUID);
252 LineStartSym = context.CreateTempSymbol();
253 // Set the value of the symbol, as we are at the start of the line table.
254 MCOS->EmitLabel(LineStartSym);
256 // Create a symbol for the end of the section (to be set when we get there).
257 MCSymbol *LineEndSym = context.CreateTempSymbol();
259 // The first 4 bytes is the total length of the information for this
260 // compilation unit (not including these 4 bytes for the length).
261 MCOS->EmitAbsValue(MakeStartMinusEndExpr(*MCOS, *LineStartSym, *LineEndSym,4),
264 // Next 2 bytes is the Version, which is Dwarf 2.
265 MCOS->EmitIntValue(2, 2);
267 // Create a symbol for the end of the prologue (to be set when we get there).
268 MCSymbol *ProEndSym = context.CreateTempSymbol(); // Lprologue_end
270 // Length of the prologue, is the next 4 bytes. Which is the start of the
271 // section to the end of the prologue. Not including the 4 bytes for the
272 // total length, the 2 bytes for the version, and these 4 bytes for the
273 // length of the prologue.
274 MCOS->EmitAbsValue(MakeStartMinusEndExpr(*MCOS, *LineStartSym, *ProEndSym,
277 // Parameters of the state machine, are next.
278 MCOS->EmitIntValue(DWARF2_LINE_MIN_INSN_LENGTH, 1);
279 MCOS->EmitIntValue(DWARF2_LINE_DEFAULT_IS_STMT, 1);
280 MCOS->EmitIntValue(DWARF2_LINE_BASE, 1);
281 MCOS->EmitIntValue(DWARF2_LINE_RANGE, 1);
282 MCOS->EmitIntValue(DWARF2_LINE_OPCODE_BASE, 1);
284 // Standard opcode lengths
285 MCOS->EmitIntValue(0, 1); // length of DW_LNS_copy
286 MCOS->EmitIntValue(1, 1); // length of DW_LNS_advance_pc
287 MCOS->EmitIntValue(1, 1); // length of DW_LNS_advance_line
288 MCOS->EmitIntValue(1, 1); // length of DW_LNS_set_file
289 MCOS->EmitIntValue(1, 1); // length of DW_LNS_set_column
290 MCOS->EmitIntValue(0, 1); // length of DW_LNS_negate_stmt
291 MCOS->EmitIntValue(0, 1); // length of DW_LNS_set_basic_block
292 MCOS->EmitIntValue(0, 1); // length of DW_LNS_const_add_pc
293 MCOS->EmitIntValue(1, 1); // length of DW_LNS_fixed_advance_pc
294 MCOS->EmitIntValue(0, 1); // length of DW_LNS_set_prologue_end
295 MCOS->EmitIntValue(0, 1); // length of DW_LNS_set_epilogue_begin
296 MCOS->EmitIntValue(1, 1); // DW_LNS_set_isa
298 // Put out the directory and file tables.
300 // First the directory table.
301 const std::vector<StringRef> &MCDwarfDirs =
302 context.getMCDwarfDirs(CUID);
303 for (unsigned i = 0; i < MCDwarfDirs.size(); i++) {
304 MCOS->EmitBytes(MCDwarfDirs[i]); // the DirectoryName
305 MCOS->EmitBytes(StringRef("\0", 1)); // the null term. of the string
307 MCOS->EmitIntValue(0, 1); // Terminate the directory list
309 // Second the file table.
310 const std::vector<MCDwarfFile *> &MCDwarfFiles =
311 MCOS->getContext().getMCDwarfFiles(CUID);
312 for (unsigned i = 1; i < MCDwarfFiles.size(); i++) {
313 MCOS->EmitBytes(MCDwarfFiles[i]->getName()); // FileName
314 MCOS->EmitBytes(StringRef("\0", 1)); // the null term. of the string
316 MCOS->EmitULEB128IntValue(MCDwarfFiles[i]->getDirIndex());
317 MCOS->EmitIntValue(0, 1); // last modification timestamp (always 0)
318 MCOS->EmitIntValue(0, 1); // filesize (always 0)
320 MCOS->EmitIntValue(0, 1); // Terminate the file list
322 // This is the end of the prologue, so set the value of the symbol at the
323 // end of the prologue (that was used in a previous expression).
324 MCOS->EmitLabel(ProEndSym);
326 // Put out the line tables.
327 const DenseMap<const MCSection *, MCLineSection *> &MCLineSections =
328 MCOS->getContext().getMCLineSections();
329 const std::vector<const MCSection *> &MCLineSectionOrder =
330 MCOS->getContext().getMCLineSectionOrder();
331 for (std::vector<const MCSection*>::const_iterator it =
332 MCLineSectionOrder.begin(), ie = MCLineSectionOrder.end(); it != ie;
334 const MCSection *Sec = *it;
335 const MCLineSection *Line = MCLineSections.lookup(Sec);
336 EmitDwarfLineTable(MCOS, Sec, Line, CUID);
339 if (MCOS->getContext().getAsmInfo().getLinkerRequiresNonEmptyDwarfLines()
340 && MCLineSectionOrder.begin() == MCLineSectionOrder.end()) {
341 // The darwin9 linker has a bug (see PR8715). For for 32-bit architectures
343 // total_length >= prologue_length + 10
344 // We are 4 bytes short, since we have total_length = 51 and
345 // prologue_length = 45
347 // The regular end_sequence should be sufficient.
348 MCDwarfLineAddr::Emit(MCOS, INT64_MAX, 0);
351 // This is the end of the section, so set the value of the symbol at the end
352 // of this section (that was used in a previous expression).
353 MCOS->EmitLabel(LineEndSym);
358 /// Utility function to write the encoding to an object writer.
359 void MCDwarfLineAddr::Write(MCObjectWriter *OW, int64_t LineDelta,
360 uint64_t AddrDelta) {
361 SmallString<256> Tmp;
362 raw_svector_ostream OS(Tmp);
363 MCDwarfLineAddr::Encode(LineDelta, AddrDelta, OS);
364 OW->WriteBytes(OS.str());
367 /// Utility function to emit the encoding to a streamer.
368 void MCDwarfLineAddr::Emit(MCStreamer *MCOS, int64_t LineDelta,
369 uint64_t AddrDelta) {
370 SmallString<256> Tmp;
371 raw_svector_ostream OS(Tmp);
372 MCDwarfLineAddr::Encode(LineDelta, AddrDelta, OS);
373 MCOS->EmitBytes(OS.str());
376 /// Utility function to encode a Dwarf pair of LineDelta and AddrDeltas.
377 void MCDwarfLineAddr::Encode(int64_t LineDelta, uint64_t AddrDelta,
379 uint64_t Temp, Opcode;
380 bool NeedCopy = false;
382 // Scale the address delta by the minimum instruction length.
383 AddrDelta = ScaleAddrDelta(AddrDelta);
385 // A LineDelta of INT64_MAX is a signal that this is actually a
386 // DW_LNE_end_sequence. We cannot use special opcodes here, since we want the
387 // end_sequence to emit the matrix entry.
388 if (LineDelta == INT64_MAX) {
389 if (AddrDelta == MAX_SPECIAL_ADDR_DELTA)
390 OS << char(dwarf::DW_LNS_const_add_pc);
392 OS << char(dwarf::DW_LNS_advance_pc);
393 encodeULEB128(AddrDelta, OS);
395 OS << char(dwarf::DW_LNS_extended_op);
397 OS << char(dwarf::DW_LNE_end_sequence);
401 // Bias the line delta by the base.
402 Temp = LineDelta - DWARF2_LINE_BASE;
404 // If the line increment is out of range of a special opcode, we must encode
405 // it with DW_LNS_advance_line.
406 if (Temp >= DWARF2_LINE_RANGE) {
407 OS << char(dwarf::DW_LNS_advance_line);
408 encodeSLEB128(LineDelta, OS);
411 Temp = 0 - DWARF2_LINE_BASE;
415 // Use DW_LNS_copy instead of a "line +0, addr +0" special opcode.
416 if (LineDelta == 0 && AddrDelta == 0) {
417 OS << char(dwarf::DW_LNS_copy);
421 // Bias the opcode by the special opcode base.
422 Temp += DWARF2_LINE_OPCODE_BASE;
424 // Avoid overflow when addr_delta is large.
425 if (AddrDelta < 256 + MAX_SPECIAL_ADDR_DELTA) {
426 // Try using a special opcode.
427 Opcode = Temp + AddrDelta * DWARF2_LINE_RANGE;
433 // Try using DW_LNS_const_add_pc followed by special op.
434 Opcode = Temp + (AddrDelta - MAX_SPECIAL_ADDR_DELTA) * DWARF2_LINE_RANGE;
436 OS << char(dwarf::DW_LNS_const_add_pc);
442 // Otherwise use DW_LNS_advance_pc.
443 OS << char(dwarf::DW_LNS_advance_pc);
444 encodeULEB128(AddrDelta, OS);
447 OS << char(dwarf::DW_LNS_copy);
452 void MCDwarfFile::print(raw_ostream &OS) const {
453 OS << '"' << getName() << '"';
456 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
457 void MCDwarfFile::dump() const {
462 // Utility function to write a tuple for .debug_abbrev.
463 static void EmitAbbrev(MCStreamer *MCOS, uint64_t Name, uint64_t Form) {
464 MCOS->EmitULEB128IntValue(Name);
465 MCOS->EmitULEB128IntValue(Form);
468 // When generating dwarf for assembly source files this emits
469 // the data for .debug_abbrev section which contains three DIEs.
470 static void EmitGenDwarfAbbrev(MCStreamer *MCOS) {
471 MCContext &context = MCOS->getContext();
472 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfAbbrevSection());
474 // DW_TAG_compile_unit DIE abbrev (1).
475 MCOS->EmitULEB128IntValue(1);
476 MCOS->EmitULEB128IntValue(dwarf::DW_TAG_compile_unit);
477 MCOS->EmitIntValue(dwarf::DW_CHILDREN_yes, 1);
478 EmitAbbrev(MCOS, dwarf::DW_AT_stmt_list, dwarf::DW_FORM_data4);
479 EmitAbbrev(MCOS, dwarf::DW_AT_low_pc, dwarf::DW_FORM_addr);
480 EmitAbbrev(MCOS, dwarf::DW_AT_high_pc, dwarf::DW_FORM_addr);
481 EmitAbbrev(MCOS, dwarf::DW_AT_name, dwarf::DW_FORM_string);
482 EmitAbbrev(MCOS, dwarf::DW_AT_comp_dir, dwarf::DW_FORM_string);
483 StringRef DwarfDebugFlags = context.getDwarfDebugFlags();
484 if (!DwarfDebugFlags.empty())
485 EmitAbbrev(MCOS, dwarf::DW_AT_APPLE_flags, dwarf::DW_FORM_string);
486 EmitAbbrev(MCOS, dwarf::DW_AT_producer, dwarf::DW_FORM_string);
487 EmitAbbrev(MCOS, dwarf::DW_AT_language, dwarf::DW_FORM_data2);
488 EmitAbbrev(MCOS, 0, 0);
490 // DW_TAG_label DIE abbrev (2).
491 MCOS->EmitULEB128IntValue(2);
492 MCOS->EmitULEB128IntValue(dwarf::DW_TAG_label);
493 MCOS->EmitIntValue(dwarf::DW_CHILDREN_yes, 1);
494 EmitAbbrev(MCOS, dwarf::DW_AT_name, dwarf::DW_FORM_string);
495 EmitAbbrev(MCOS, dwarf::DW_AT_decl_file, dwarf::DW_FORM_data4);
496 EmitAbbrev(MCOS, dwarf::DW_AT_decl_line, dwarf::DW_FORM_data4);
497 EmitAbbrev(MCOS, dwarf::DW_AT_low_pc, dwarf::DW_FORM_addr);
498 EmitAbbrev(MCOS, dwarf::DW_AT_prototyped, dwarf::DW_FORM_flag);
499 EmitAbbrev(MCOS, 0, 0);
501 // DW_TAG_unspecified_parameters DIE abbrev (3).
502 MCOS->EmitULEB128IntValue(3);
503 MCOS->EmitULEB128IntValue(dwarf::DW_TAG_unspecified_parameters);
504 MCOS->EmitIntValue(dwarf::DW_CHILDREN_no, 1);
505 EmitAbbrev(MCOS, 0, 0);
507 // Terminate the abbreviations for this compilation unit.
508 MCOS->EmitIntValue(0, 1);
511 // When generating dwarf for assembly source files this emits the data for
512 // .debug_aranges section. Which contains a header and a table of pairs of
513 // PointerSize'ed values for the address and size of section(s) with line table
514 // entries (just the default .text in our case) and a terminating pair of zeros.
515 static void EmitGenDwarfAranges(MCStreamer *MCOS,
516 const MCSymbol *InfoSectionSymbol) {
517 MCContext &context = MCOS->getContext();
519 // Create a symbol at the end of the section that we are creating the dwarf
520 // debugging info to use later in here as part of the expression to calculate
521 // the size of the section for the table.
522 MCOS->SwitchSection(context.getGenDwarfSection());
523 MCSymbol *SectionEndSym = context.CreateTempSymbol();
524 MCOS->EmitLabel(SectionEndSym);
525 context.setGenDwarfSectionEndSym(SectionEndSym);
527 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfARangesSection());
529 // This will be the length of the .debug_aranges section, first account for
530 // the size of each item in the header (see below where we emit these items).
531 int Length = 4 + 2 + 4 + 1 + 1;
533 // Figure the padding after the header before the table of address and size
534 // pairs who's values are PointerSize'ed.
535 const MCAsmInfo &asmInfo = context.getAsmInfo();
536 int AddrSize = asmInfo.getPointerSize();
537 int Pad = 2 * AddrSize - (Length & (2 * AddrSize - 1));
538 if (Pad == 2 * AddrSize)
542 // Add the size of the pair of PointerSize'ed values for the address and size
543 // of the one default .text section we have in the table.
544 Length += 2 * AddrSize;
545 // And the pair of terminating zeros.
546 Length += 2 * AddrSize;
549 // Emit the header for this section.
550 // The 4 byte length not including the 4 byte value for the length.
551 MCOS->EmitIntValue(Length - 4, 4);
552 // The 2 byte version, which is 2.
553 MCOS->EmitIntValue(2, 2);
554 // The 4 byte offset to the compile unit in the .debug_info from the start
555 // of the .debug_info.
556 if (InfoSectionSymbol)
557 MCOS->EmitSymbolValue(InfoSectionSymbol, 4);
559 MCOS->EmitIntValue(0, 4);
560 // The 1 byte size of an address.
561 MCOS->EmitIntValue(AddrSize, 1);
562 // The 1 byte size of a segment descriptor, we use a value of zero.
563 MCOS->EmitIntValue(0, 1);
564 // Align the header with the padding if needed, before we put out the table.
565 for(int i = 0; i < Pad; i++)
566 MCOS->EmitIntValue(0, 1);
568 // Now emit the table of pairs of PointerSize'ed values for the section(s)
569 // address and size, in our case just the one default .text section.
570 const MCExpr *Addr = MCSymbolRefExpr::Create(
571 context.getGenDwarfSectionStartSym(), MCSymbolRefExpr::VK_None, context);
572 const MCExpr *Size = MakeStartMinusEndExpr(*MCOS,
573 *context.getGenDwarfSectionStartSym(), *SectionEndSym, 0);
574 MCOS->EmitAbsValue(Addr, AddrSize);
575 MCOS->EmitAbsValue(Size, AddrSize);
577 // And finally the pair of terminating zeros.
578 MCOS->EmitIntValue(0, AddrSize);
579 MCOS->EmitIntValue(0, AddrSize);
582 // When generating dwarf for assembly source files this emits the data for
583 // .debug_info section which contains three parts. The header, the compile_unit
584 // DIE and a list of label DIEs.
585 static void EmitGenDwarfInfo(MCStreamer *MCOS,
586 const MCSymbol *AbbrevSectionSymbol,
587 const MCSymbol *LineSectionSymbol) {
588 MCContext &context = MCOS->getContext();
590 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfInfoSection());
592 // Create a symbol at the start and end of this section used in here for the
593 // expression to calculate the length in the header.
594 MCSymbol *InfoStart = context.CreateTempSymbol();
595 MCOS->EmitLabel(InfoStart);
596 MCSymbol *InfoEnd = context.CreateTempSymbol();
598 // First part: the header.
600 // The 4 byte total length of the information for this compilation unit, not
601 // including these 4 bytes.
602 const MCExpr *Length = MakeStartMinusEndExpr(*MCOS, *InfoStart, *InfoEnd, 4);
603 MCOS->EmitAbsValue(Length, 4);
605 // The 2 byte DWARF version, which is 2.
606 MCOS->EmitIntValue(2, 2);
608 // The 4 byte offset to the debug abbrevs from the start of the .debug_abbrev,
609 // it is at the start of that section so this is zero.
610 if (AbbrevSectionSymbol) {
611 MCOS->EmitSymbolValue(AbbrevSectionSymbol, 4);
613 MCOS->EmitIntValue(0, 4);
616 const MCAsmInfo &asmInfo = context.getAsmInfo();
617 int AddrSize = asmInfo.getPointerSize();
618 // The 1 byte size of an address.
619 MCOS->EmitIntValue(AddrSize, 1);
621 // Second part: the compile_unit DIE.
623 // The DW_TAG_compile_unit DIE abbrev (1).
624 MCOS->EmitULEB128IntValue(1);
626 // DW_AT_stmt_list, a 4 byte offset from the start of the .debug_line section,
627 // which is at the start of that section so this is zero.
628 if (LineSectionSymbol) {
629 MCOS->EmitSymbolValue(LineSectionSymbol, 4);
631 MCOS->EmitIntValue(0, 4);
634 // AT_low_pc, the first address of the default .text section.
635 const MCExpr *Start = MCSymbolRefExpr::Create(
636 context.getGenDwarfSectionStartSym(), MCSymbolRefExpr::VK_None, context);
637 MCOS->EmitAbsValue(Start, AddrSize);
639 // AT_high_pc, the last address of the default .text section.
640 const MCExpr *End = MCSymbolRefExpr::Create(
641 context.getGenDwarfSectionEndSym(), MCSymbolRefExpr::VK_None, context);
642 MCOS->EmitAbsValue(End, AddrSize);
644 // AT_name, the name of the source file. Reconstruct from the first directory
645 // and file table entries.
646 const std::vector<StringRef> &MCDwarfDirs =
647 context.getMCDwarfDirs();
648 if (MCDwarfDirs.size() > 0) {
649 MCOS->EmitBytes(MCDwarfDirs[0]);
650 MCOS->EmitBytes("/");
652 const std::vector<MCDwarfFile *> &MCDwarfFiles =
653 MCOS->getContext().getMCDwarfFiles();
654 MCOS->EmitBytes(MCDwarfFiles[1]->getName());
655 MCOS->EmitIntValue(0, 1); // NULL byte to terminate the string.
657 // AT_comp_dir, the working directory the assembly was done in.
658 MCOS->EmitBytes(context.getCompilationDir());
659 MCOS->EmitIntValue(0, 1); // NULL byte to terminate the string.
661 // AT_APPLE_flags, the command line arguments of the assembler tool.
662 StringRef DwarfDebugFlags = context.getDwarfDebugFlags();
663 if (!DwarfDebugFlags.empty()){
664 MCOS->EmitBytes(DwarfDebugFlags);
665 MCOS->EmitIntValue(0, 1); // NULL byte to terminate the string.
668 // AT_producer, the version of the assembler tool.
669 StringRef DwarfDebugProducer = context.getDwarfDebugProducer();
670 if (!DwarfDebugProducer.empty()){
671 MCOS->EmitBytes(DwarfDebugProducer);
674 MCOS->EmitBytes(StringRef("llvm-mc (based on LLVM "));
675 MCOS->EmitBytes(StringRef(PACKAGE_VERSION));
676 MCOS->EmitBytes(StringRef(")"));
678 MCOS->EmitIntValue(0, 1); // NULL byte to terminate the string.
680 // AT_language, a 4 byte value. We use DW_LANG_Mips_Assembler as the dwarf2
681 // draft has no standard code for assembler.
682 MCOS->EmitIntValue(dwarf::DW_LANG_Mips_Assembler, 2);
684 // Third part: the list of label DIEs.
686 // Loop on saved info for dwarf labels and create the DIEs for them.
687 const std::vector<const MCGenDwarfLabelEntry *> &Entries =
688 MCOS->getContext().getMCGenDwarfLabelEntries();
689 for (std::vector<const MCGenDwarfLabelEntry *>::const_iterator it =
690 Entries.begin(), ie = Entries.end(); it != ie;
692 const MCGenDwarfLabelEntry *Entry = *it;
694 // The DW_TAG_label DIE abbrev (2).
695 MCOS->EmitULEB128IntValue(2);
697 // AT_name, of the label without any leading underbar.
698 MCOS->EmitBytes(Entry->getName());
699 MCOS->EmitIntValue(0, 1); // NULL byte to terminate the string.
701 // AT_decl_file, index into the file table.
702 MCOS->EmitIntValue(Entry->getFileNumber(), 4);
704 // AT_decl_line, source line number.
705 MCOS->EmitIntValue(Entry->getLineNumber(), 4);
707 // AT_low_pc, start address of the label.
708 const MCExpr *AT_low_pc = MCSymbolRefExpr::Create(Entry->getLabel(),
709 MCSymbolRefExpr::VK_None, context);
710 MCOS->EmitAbsValue(AT_low_pc, AddrSize);
712 // DW_AT_prototyped, a one byte flag value of 0 saying we have no prototype.
713 MCOS->EmitIntValue(0, 1);
715 // The DW_TAG_unspecified_parameters DIE abbrev (3).
716 MCOS->EmitULEB128IntValue(3);
718 // Add the NULL DIE terminating the DW_TAG_unspecified_parameters DIE's.
719 MCOS->EmitIntValue(0, 1);
721 // Deallocate the MCGenDwarfLabelEntry classes that saved away the info
722 // for the dwarf labels.
723 for (std::vector<const MCGenDwarfLabelEntry *>::const_iterator it =
724 Entries.begin(), ie = Entries.end(); it != ie;
726 const MCGenDwarfLabelEntry *Entry = *it;
730 // Add the NULL DIE terminating the Compile Unit DIE's.
731 MCOS->EmitIntValue(0, 1);
733 // Now set the value of the symbol at the end of the info section.
734 MCOS->EmitLabel(InfoEnd);
738 // When generating dwarf for assembly source files this emits the Dwarf
741 void MCGenDwarfInfo::Emit(MCStreamer *MCOS, const MCSymbol *LineSectionSymbol) {
742 // Create the dwarf sections in this order (.debug_line already created).
743 MCContext &context = MCOS->getContext();
744 const MCAsmInfo &AsmInfo = context.getAsmInfo();
745 bool CreateDwarfSectionSymbols =
746 AsmInfo.doesDwarfUseRelocationsAcrossSections();
747 if (!CreateDwarfSectionSymbols)
748 LineSectionSymbol = NULL;
749 MCSymbol *AbbrevSectionSymbol = NULL;
750 MCSymbol *InfoSectionSymbol = NULL;
751 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfInfoSection());
752 if (CreateDwarfSectionSymbols) {
753 InfoSectionSymbol = context.CreateTempSymbol();
754 MCOS->EmitLabel(InfoSectionSymbol);
756 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfAbbrevSection());
757 if (CreateDwarfSectionSymbols) {
758 AbbrevSectionSymbol = context.CreateTempSymbol();
759 MCOS->EmitLabel(AbbrevSectionSymbol);
761 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfARangesSection());
763 // If there are no line table entries then do not emit any section contents.
764 if (context.getMCLineSections().empty())
767 // Output the data for .debug_aranges section.
768 EmitGenDwarfAranges(MCOS, InfoSectionSymbol);
770 // Output the data for .debug_abbrev section.
771 EmitGenDwarfAbbrev(MCOS);
773 // Output the data for .debug_info section.
774 EmitGenDwarfInfo(MCOS, AbbrevSectionSymbol, LineSectionSymbol);
778 // When generating dwarf for assembly source files this is called when symbol
779 // for a label is created. If this symbol is not a temporary and is in the
780 // section that dwarf is being generated for, save the needed info to create
783 void MCGenDwarfLabelEntry::Make(MCSymbol *Symbol, MCStreamer *MCOS,
784 SourceMgr &SrcMgr, SMLoc &Loc) {
785 // We won't create dwarf labels for temporary symbols or symbols not in
787 if (Symbol->isTemporary())
789 MCContext &context = MCOS->getContext();
790 if (context.getGenDwarfSection() != MCOS->getCurrentSection())
793 // The dwarf label's name does not have the symbol name's leading
795 StringRef Name = Symbol->getName();
796 if (Name.startswith("_"))
797 Name = Name.substr(1, Name.size()-1);
799 // Get the dwarf file number to be used for the dwarf label.
800 unsigned FileNumber = context.getGenDwarfFileNumber();
802 // Finding the line number is the expensive part which is why we just don't
803 // pass it in as for some symbols we won't create a dwarf label.
804 int CurBuffer = SrcMgr.FindBufferContainingLoc(Loc);
805 unsigned LineNumber = SrcMgr.FindLineNumber(Loc, CurBuffer);
807 // We create a temporary symbol for use for the AT_high_pc and AT_low_pc
808 // values so that they don't have things like an ARM thumb bit from the
809 // original symbol. So when used they won't get a low bit set after
811 MCSymbol *Label = context.CreateTempSymbol();
812 MCOS->EmitLabel(Label);
814 // Create and entry for the info and add it to the other entries.
815 MCGenDwarfLabelEntry *Entry =
816 new MCGenDwarfLabelEntry(Name, FileNumber, LineNumber, Label);
817 MCOS->getContext().addMCGenDwarfLabelEntry(Entry);
820 static int getDataAlignmentFactor(MCStreamer &streamer) {
821 MCContext &context = streamer.getContext();
822 const MCAsmInfo &asmInfo = context.getAsmInfo();
823 int size = asmInfo.getCalleeSaveStackSlotSize();
824 if (asmInfo.isStackGrowthDirectionUp())
830 static unsigned getSizeForEncoding(MCStreamer &streamer,
831 unsigned symbolEncoding) {
832 MCContext &context = streamer.getContext();
833 unsigned format = symbolEncoding & 0x0f;
835 default: llvm_unreachable("Unknown Encoding");
836 case dwarf::DW_EH_PE_absptr:
837 case dwarf::DW_EH_PE_signed:
838 return context.getAsmInfo().getPointerSize();
839 case dwarf::DW_EH_PE_udata2:
840 case dwarf::DW_EH_PE_sdata2:
842 case dwarf::DW_EH_PE_udata4:
843 case dwarf::DW_EH_PE_sdata4:
845 case dwarf::DW_EH_PE_udata8:
846 case dwarf::DW_EH_PE_sdata8:
851 static void EmitSymbol(MCStreamer &streamer, const MCSymbol &symbol,
852 unsigned symbolEncoding, const char *comment = 0) {
853 MCContext &context = streamer.getContext();
854 const MCAsmInfo &asmInfo = context.getAsmInfo();
855 const MCExpr *v = asmInfo.getExprForFDESymbol(&symbol,
858 unsigned size = getSizeForEncoding(streamer, symbolEncoding);
859 if (streamer.isVerboseAsm() && comment) streamer.AddComment(comment);
860 streamer.EmitAbsValue(v, size);
863 static void EmitPersonality(MCStreamer &streamer, const MCSymbol &symbol,
864 unsigned symbolEncoding) {
865 MCContext &context = streamer.getContext();
866 const MCAsmInfo &asmInfo = context.getAsmInfo();
867 const MCExpr *v = asmInfo.getExprForPersonalitySymbol(&symbol,
870 unsigned size = getSizeForEncoding(streamer, symbolEncoding);
871 streamer.EmitValue(v, size);
874 static const MachineLocation TranslateMachineLocation(
875 const MCRegisterInfo &MRI,
876 const MachineLocation &Loc) {
877 unsigned Reg = Loc.getReg() == MachineLocation::VirtualFP ?
878 MachineLocation::VirtualFP :
879 unsigned(MRI.getDwarfRegNum(Loc.getReg(), true));
880 const MachineLocation &NewLoc = Loc.isReg() ?
881 MachineLocation(Reg) : MachineLocation(Reg, Loc.getOffset());
886 class FrameEmitterImpl {
891 const MCSymbol *SectionStart;
893 FrameEmitterImpl(bool usingCFI, bool isEH)
894 : CFAOffset(0), CIENum(0), UsingCFI(usingCFI), IsEH(isEH),
897 void setSectionStart(const MCSymbol *Label) { SectionStart = Label; }
899 /// EmitCompactUnwind - Emit the unwind information in a compact way. If
900 /// we're successful, return 'true'. Otherwise, return 'false' and it will
901 /// emit the normal CIE and FDE.
902 bool EmitCompactUnwind(MCStreamer &streamer,
903 const MCDwarfFrameInfo &frame);
905 const MCSymbol &EmitCIE(MCStreamer &streamer,
906 const MCSymbol *personality,
907 unsigned personalityEncoding,
908 const MCSymbol *lsda,
910 unsigned lsdaEncoding);
911 MCSymbol *EmitFDE(MCStreamer &streamer,
912 const MCSymbol &cieStart,
913 const MCDwarfFrameInfo &frame);
914 void EmitCFIInstructions(MCStreamer &streamer,
915 const std::vector<MCCFIInstruction> &Instrs,
916 MCSymbol *BaseLabel);
917 void EmitCFIInstruction(MCStreamer &Streamer,
918 const MCCFIInstruction &Instr);
921 } // end anonymous namespace
923 static void EmitEncodingByte(MCStreamer &Streamer, unsigned Encoding,
925 if (Streamer.isVerboseAsm()) {
928 default: EncStr = "<unknown encoding>"; break;
929 case dwarf::DW_EH_PE_absptr: EncStr = "absptr"; break;
930 case dwarf::DW_EH_PE_omit: EncStr = "omit"; break;
931 case dwarf::DW_EH_PE_pcrel: EncStr = "pcrel"; break;
932 case dwarf::DW_EH_PE_udata4: EncStr = "udata4"; break;
933 case dwarf::DW_EH_PE_udata8: EncStr = "udata8"; break;
934 case dwarf::DW_EH_PE_sdata4: EncStr = "sdata4"; break;
935 case dwarf::DW_EH_PE_sdata8: EncStr = "sdata8"; break;
936 case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata4:
937 EncStr = "pcrel udata4";
939 case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4:
940 EncStr = "pcrel sdata4";
942 case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata8:
943 EncStr = "pcrel udata8";
945 case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata8:
946 EncStr = "screl sdata8";
948 case dwarf::DW_EH_PE_indirect |dwarf::DW_EH_PE_pcrel|dwarf::DW_EH_PE_udata4:
949 EncStr = "indirect pcrel udata4";
951 case dwarf::DW_EH_PE_indirect |dwarf::DW_EH_PE_pcrel|dwarf::DW_EH_PE_sdata4:
952 EncStr = "indirect pcrel sdata4";
954 case dwarf::DW_EH_PE_indirect |dwarf::DW_EH_PE_pcrel|dwarf::DW_EH_PE_udata8:
955 EncStr = "indirect pcrel udata8";
957 case dwarf::DW_EH_PE_indirect |dwarf::DW_EH_PE_pcrel|dwarf::DW_EH_PE_sdata8:
958 EncStr = "indirect pcrel sdata8";
962 Streamer.AddComment(Twine(Prefix) + " = " + EncStr);
965 Streamer.EmitIntValue(Encoding, 1);
968 void FrameEmitterImpl::EmitCFIInstruction(MCStreamer &Streamer,
969 const MCCFIInstruction &Instr) {
970 int dataAlignmentFactor = getDataAlignmentFactor(Streamer);
971 bool VerboseAsm = Streamer.isVerboseAsm();
973 switch (Instr.getOperation()) {
974 case MCCFIInstruction::OpRegister: {
975 unsigned Reg1 = Instr.getRegister();
976 unsigned Reg2 = Instr.getRegister2();
978 Streamer.AddComment("DW_CFA_register");
979 Streamer.AddComment(Twine("Reg1 ") + Twine(Reg1));
980 Streamer.AddComment(Twine("Reg2 ") + Twine(Reg2));
982 Streamer.EmitIntValue(dwarf::DW_CFA_register, 1);
983 Streamer.EmitULEB128IntValue(Reg1);
984 Streamer.EmitULEB128IntValue(Reg2);
987 case MCCFIInstruction::OpUndefined: {
988 unsigned Reg = Instr.getRegister();
990 Streamer.AddComment("DW_CFA_undefined");
991 Streamer.AddComment(Twine("Reg ") + Twine(Reg));
993 Streamer.EmitIntValue(dwarf::DW_CFA_undefined, 1);
994 Streamer.EmitULEB128IntValue(Reg);
997 case MCCFIInstruction::OpAdjustCfaOffset:
998 case MCCFIInstruction::OpDefCfaOffset: {
999 const bool IsRelative =
1000 Instr.getOperation() == MCCFIInstruction::OpAdjustCfaOffset;
1003 Streamer.AddComment("DW_CFA_def_cfa_offset");
1004 Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa_offset, 1);
1007 CFAOffset += Instr.getOffset();
1009 CFAOffset = -Instr.getOffset();
1012 Streamer.AddComment(Twine("Offset " + Twine(CFAOffset)));
1013 Streamer.EmitULEB128IntValue(CFAOffset);
1017 case MCCFIInstruction::OpDefCfa: {
1019 Streamer.AddComment("DW_CFA_def_cfa");
1020 Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa, 1);
1023 Streamer.AddComment(Twine("Reg ") + Twine(Instr.getRegister()));
1024 Streamer.EmitULEB128IntValue(Instr.getRegister());
1026 CFAOffset = -Instr.getOffset();
1029 Streamer.AddComment(Twine("Offset " + Twine(CFAOffset)));
1030 Streamer.EmitULEB128IntValue(CFAOffset);
1035 case MCCFIInstruction::OpDefCfaRegister: {
1037 Streamer.AddComment("DW_CFA_def_cfa_register");
1038 Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa_register, 1);
1041 Streamer.AddComment(Twine("Reg ") + Twine(Instr.getRegister()));
1042 Streamer.EmitULEB128IntValue(Instr.getRegister());
1047 case MCCFIInstruction::OpOffset:
1048 case MCCFIInstruction::OpRelOffset: {
1049 const bool IsRelative =
1050 Instr.getOperation() == MCCFIInstruction::OpRelOffset;
1052 unsigned Reg = Instr.getRegister();
1053 int Offset = Instr.getOffset();
1055 Offset -= CFAOffset;
1056 Offset = Offset / dataAlignmentFactor;
1059 if (VerboseAsm) Streamer.AddComment("DW_CFA_offset_extended_sf");
1060 Streamer.EmitIntValue(dwarf::DW_CFA_offset_extended_sf, 1);
1061 if (VerboseAsm) Streamer.AddComment(Twine("Reg ") + Twine(Reg));
1062 Streamer.EmitULEB128IntValue(Reg);
1063 if (VerboseAsm) Streamer.AddComment(Twine("Offset ") + Twine(Offset));
1064 Streamer.EmitSLEB128IntValue(Offset);
1065 } else if (Reg < 64) {
1066 if (VerboseAsm) Streamer.AddComment(Twine("DW_CFA_offset + Reg(") +
1068 Streamer.EmitIntValue(dwarf::DW_CFA_offset + Reg, 1);
1069 if (VerboseAsm) Streamer.AddComment(Twine("Offset ") + Twine(Offset));
1070 Streamer.EmitULEB128IntValue(Offset);
1072 if (VerboseAsm) Streamer.AddComment("DW_CFA_offset_extended");
1073 Streamer.EmitIntValue(dwarf::DW_CFA_offset_extended, 1);
1074 if (VerboseAsm) Streamer.AddComment(Twine("Reg ") + Twine(Reg));
1075 Streamer.EmitULEB128IntValue(Reg);
1076 if (VerboseAsm) Streamer.AddComment(Twine("Offset ") + Twine(Offset));
1077 Streamer.EmitULEB128IntValue(Offset);
1081 case MCCFIInstruction::OpRememberState:
1082 if (VerboseAsm) Streamer.AddComment("DW_CFA_remember_state");
1083 Streamer.EmitIntValue(dwarf::DW_CFA_remember_state, 1);
1085 case MCCFIInstruction::OpRestoreState:
1086 if (VerboseAsm) Streamer.AddComment("DW_CFA_restore_state");
1087 Streamer.EmitIntValue(dwarf::DW_CFA_restore_state, 1);
1089 case MCCFIInstruction::OpSameValue: {
1090 unsigned Reg = Instr.getRegister();
1091 if (VerboseAsm) Streamer.AddComment("DW_CFA_same_value");
1092 Streamer.EmitIntValue(dwarf::DW_CFA_same_value, 1);
1093 if (VerboseAsm) Streamer.AddComment(Twine("Reg ") + Twine(Reg));
1094 Streamer.EmitULEB128IntValue(Reg);
1097 case MCCFIInstruction::OpRestore: {
1098 unsigned Reg = Instr.getRegister();
1100 Streamer.AddComment("DW_CFA_restore");
1101 Streamer.AddComment(Twine("Reg ") + Twine(Reg));
1103 Streamer.EmitIntValue(dwarf::DW_CFA_restore | Reg, 1);
1106 case MCCFIInstruction::OpEscape:
1107 if (VerboseAsm) Streamer.AddComment("Escape bytes");
1108 Streamer.EmitBytes(Instr.getValues());
1111 llvm_unreachable("Unhandled case in switch");
1114 /// EmitFrameMoves - Emit frame instructions to describe the layout of the
1116 void FrameEmitterImpl::EmitCFIInstructions(MCStreamer &streamer,
1117 const std::vector<MCCFIInstruction> &Instrs,
1118 MCSymbol *BaseLabel) {
1119 for (unsigned i = 0, N = Instrs.size(); i < N; ++i) {
1120 const MCCFIInstruction &Instr = Instrs[i];
1121 MCSymbol *Label = Instr.getLabel();
1122 // Throw out move if the label is invalid.
1123 if (Label && !Label->isDefined()) continue; // Not emitted, in dead code.
1125 // Advance row if new location.
1126 if (BaseLabel && Label) {
1127 MCSymbol *ThisSym = Label;
1128 if (ThisSym != BaseLabel) {
1129 if (streamer.isVerboseAsm()) streamer.AddComment("DW_CFA_advance_loc4");
1130 streamer.EmitDwarfAdvanceFrameAddr(BaseLabel, ThisSym);
1131 BaseLabel = ThisSym;
1135 EmitCFIInstruction(streamer, Instr);
1139 /// EmitCompactUnwind - Emit the unwind information in a compact way. If we're
1140 /// successful, return 'true'. Otherwise, return 'false' and it will emit the
1141 /// normal CIE and FDE.
1142 bool FrameEmitterImpl::EmitCompactUnwind(MCStreamer &Streamer,
1143 const MCDwarfFrameInfo &Frame) {
1144 MCContext &Context = Streamer.getContext();
1145 const MCObjectFileInfo *MOFI = Context.getObjectFileInfo();
1146 bool VerboseAsm = Streamer.isVerboseAsm();
1148 // range-start range-length compact-unwind-enc personality-func lsda
1149 // _foo LfooEnd-_foo 0x00000023 0 0
1150 // _bar LbarEnd-_bar 0x00000025 __gxx_personality except_tab1
1152 // .section __LD,__compact_unwind,regular,debug
1154 // # compact unwind for _foo
1156 // .set L1,LfooEnd-_foo
1162 // # compact unwind for _bar
1164 // .set L2,LbarEnd-_bar
1167 // .quad __gxx_personality
1168 // .quad except_tab1
1170 uint32_t Encoding = Frame.CompactUnwindEncoding;
1171 if (!Encoding) return false;
1173 // The encoding needs to know we have an LSDA.
1175 Encoding |= 0x40000000;
1177 Streamer.SwitchSection(MOFI->getCompactUnwindSection());
1180 unsigned FDEEncoding = MOFI->getFDEEncoding(UsingCFI);
1181 unsigned Size = getSizeForEncoding(Streamer, FDEEncoding);
1182 if (VerboseAsm) Streamer.AddComment("Range Start");
1183 Streamer.EmitSymbolValue(Frame.Function, Size);
1186 const MCExpr *Range = MakeStartMinusEndExpr(Streamer, *Frame.Begin,
1188 if (VerboseAsm) Streamer.AddComment("Range Length");
1189 Streamer.EmitAbsValue(Range, 4);
1192 Size = getSizeForEncoding(Streamer, dwarf::DW_EH_PE_udata4);
1193 if (VerboseAsm) Streamer.AddComment("Compact Unwind Encoding: 0x" +
1194 Twine::utohexstr(Encoding));
1195 Streamer.EmitIntValue(Encoding, Size);
1198 // Personality Function
1199 Size = getSizeForEncoding(Streamer, dwarf::DW_EH_PE_absptr);
1200 if (VerboseAsm) Streamer.AddComment("Personality Function");
1201 if (Frame.Personality)
1202 Streamer.EmitSymbolValue(Frame.Personality, Size);
1204 Streamer.EmitIntValue(0, Size); // No personality fn
1207 Size = getSizeForEncoding(Streamer, Frame.LsdaEncoding);
1208 if (VerboseAsm) Streamer.AddComment("LSDA");
1210 Streamer.EmitSymbolValue(Frame.Lsda, Size);
1212 Streamer.EmitIntValue(0, Size); // No LSDA
1217 const MCSymbol &FrameEmitterImpl::EmitCIE(MCStreamer &streamer,
1218 const MCSymbol *personality,
1219 unsigned personalityEncoding,
1220 const MCSymbol *lsda,
1222 unsigned lsdaEncoding) {
1223 MCContext &context = streamer.getContext();
1224 const MCRegisterInfo &MRI = context.getRegisterInfo();
1225 const MCObjectFileInfo *MOFI = context.getObjectFileInfo();
1226 bool verboseAsm = streamer.isVerboseAsm();
1228 MCSymbol *sectionStart;
1229 if (MOFI->isFunctionEHFrameSymbolPrivate() || !IsEH)
1230 sectionStart = context.CreateTempSymbol();
1232 sectionStart = context.GetOrCreateSymbol(Twine("EH_frame") + Twine(CIENum));
1234 streamer.EmitLabel(sectionStart);
1237 MCSymbol *sectionEnd = context.CreateTempSymbol();
1240 const MCExpr *Length = MakeStartMinusEndExpr(streamer, *sectionStart,
1242 if (verboseAsm) streamer.AddComment("CIE Length");
1243 streamer.EmitAbsValue(Length, 4);
1246 unsigned CIE_ID = IsEH ? 0 : -1;
1247 if (verboseAsm) streamer.AddComment("CIE ID Tag");
1248 streamer.EmitIntValue(CIE_ID, 4);
1251 if (verboseAsm) streamer.AddComment("DW_CIE_VERSION");
1252 streamer.EmitIntValue(dwarf::DW_CIE_VERSION, 1);
1254 // Augmentation String
1255 SmallString<8> Augmentation;
1257 if (verboseAsm) streamer.AddComment("CIE Augmentation");
1258 Augmentation += "z";
1260 Augmentation += "P";
1262 Augmentation += "L";
1263 Augmentation += "R";
1265 Augmentation += "S";
1266 streamer.EmitBytes(Augmentation.str());
1268 streamer.EmitIntValue(0, 1);
1270 // Code Alignment Factor
1271 if (verboseAsm) streamer.AddComment("CIE Code Alignment Factor");
1272 streamer.EmitULEB128IntValue(1);
1274 // Data Alignment Factor
1275 if (verboseAsm) streamer.AddComment("CIE Data Alignment Factor");
1276 streamer.EmitSLEB128IntValue(getDataAlignmentFactor(streamer));
1278 // Return Address Register
1279 if (verboseAsm) streamer.AddComment("CIE Return Address Column");
1280 streamer.EmitULEB128IntValue(MRI.getDwarfRegNum(MRI.getRARegister(), true));
1282 // Augmentation Data Length (optional)
1284 unsigned augmentationLength = 0;
1287 // Personality Encoding
1288 augmentationLength += 1;
1290 augmentationLength += getSizeForEncoding(streamer, personalityEncoding);
1293 augmentationLength += 1;
1294 // Encoding of the FDE pointers
1295 augmentationLength += 1;
1297 if (verboseAsm) streamer.AddComment("Augmentation Size");
1298 streamer.EmitULEB128IntValue(augmentationLength);
1300 // Augmentation Data (optional)
1302 // Personality Encoding
1303 EmitEncodingByte(streamer, personalityEncoding,
1304 "Personality Encoding");
1306 if (verboseAsm) streamer.AddComment("Personality");
1307 EmitPersonality(streamer, *personality, personalityEncoding);
1311 EmitEncodingByte(streamer, lsdaEncoding, "LSDA Encoding");
1313 // Encoding of the FDE pointers
1314 EmitEncodingByte(streamer, MOFI->getFDEEncoding(UsingCFI),
1318 // Initial Instructions
1320 const MCAsmInfo &MAI = context.getAsmInfo();
1321 const std::vector<MachineMove> &Moves = MAI.getInitialFrameState();
1322 std::vector<MCCFIInstruction> Instructions;
1324 for (int i = 0, n = Moves.size(); i != n; ++i) {
1325 MCSymbol *Label = Moves[i].getLabel();
1326 const MachineLocation &Dst =
1327 TranslateMachineLocation(MRI, Moves[i].getDestination());
1328 const MachineLocation &Src =
1329 TranslateMachineLocation(MRI, Moves[i].getSource());
1332 assert(Dst.getReg() == MachineLocation::VirtualFP);
1333 assert(!Src.isReg());
1334 MCCFIInstruction Inst =
1335 MCCFIInstruction::createDefCfa(Label, Src.getReg(), -Src.getOffset());
1336 Instructions.push_back(Inst);
1338 assert(Src.isReg());
1339 unsigned Reg = Src.getReg();
1340 int Offset = Dst.getOffset();
1341 MCCFIInstruction Inst =
1342 MCCFIInstruction::createOffset(Label, Reg, Offset);
1343 Instructions.push_back(Inst);
1347 EmitCFIInstructions(streamer, Instructions, NULL);
1350 streamer.EmitValueToAlignment(IsEH
1351 ? 4 : context.getAsmInfo().getPointerSize());
1353 streamer.EmitLabel(sectionEnd);
1354 return *sectionStart;
1357 MCSymbol *FrameEmitterImpl::EmitFDE(MCStreamer &streamer,
1358 const MCSymbol &cieStart,
1359 const MCDwarfFrameInfo &frame) {
1360 MCContext &context = streamer.getContext();
1361 MCSymbol *fdeStart = context.CreateTempSymbol();
1362 MCSymbol *fdeEnd = context.CreateTempSymbol();
1363 const MCObjectFileInfo *MOFI = context.getObjectFileInfo();
1364 bool verboseAsm = streamer.isVerboseAsm();
1366 if (IsEH && frame.Function && !MOFI->isFunctionEHFrameSymbolPrivate()) {
1368 context.GetOrCreateSymbol(frame.Function->getName() + Twine(".eh"));
1369 streamer.EmitEHSymAttributes(frame.Function, EHSym);
1370 streamer.EmitLabel(EHSym);
1374 const MCExpr *Length = MakeStartMinusEndExpr(streamer, *fdeStart, *fdeEnd, 0);
1375 if (verboseAsm) streamer.AddComment("FDE Length");
1376 streamer.EmitAbsValue(Length, 4);
1378 streamer.EmitLabel(fdeStart);
1381 const MCAsmInfo &asmInfo = context.getAsmInfo();
1383 const MCExpr *offset = MakeStartMinusEndExpr(streamer, cieStart, *fdeStart,
1385 if (verboseAsm) streamer.AddComment("FDE CIE Offset");
1386 streamer.EmitAbsValue(offset, 4);
1387 } else if (!asmInfo.doesDwarfUseRelocationsAcrossSections()) {
1388 const MCExpr *offset = MakeStartMinusEndExpr(streamer, *SectionStart,
1390 streamer.EmitAbsValue(offset, 4);
1392 streamer.EmitSymbolValue(&cieStart, 4);
1396 unsigned PCEncoding = IsEH ? MOFI->getFDEEncoding(UsingCFI)
1397 : (unsigned)dwarf::DW_EH_PE_absptr;
1398 unsigned PCSize = getSizeForEncoding(streamer, PCEncoding);
1399 EmitSymbol(streamer, *frame.Begin, PCEncoding, "FDE initial location");
1402 const MCExpr *Range = MakeStartMinusEndExpr(streamer, *frame.Begin,
1404 if (verboseAsm) streamer.AddComment("FDE address range");
1405 streamer.EmitAbsValue(Range, PCSize);
1408 // Augmentation Data Length
1409 unsigned augmentationLength = 0;
1412 augmentationLength += getSizeForEncoding(streamer, frame.LsdaEncoding);
1414 if (verboseAsm) streamer.AddComment("Augmentation size");
1415 streamer.EmitULEB128IntValue(augmentationLength);
1417 // Augmentation Data
1419 EmitSymbol(streamer, *frame.Lsda, frame.LsdaEncoding,
1420 "Language Specific Data Area");
1423 // Call Frame Instructions
1425 EmitCFIInstructions(streamer, frame.Instructions, frame.Begin);
1428 streamer.EmitValueToAlignment(PCSize);
1435 static const CIEKey getEmptyKey() { return CIEKey(0, 0, -1, false); }
1436 static const CIEKey getTombstoneKey() { return CIEKey(0, -1, 0, false); }
1438 CIEKey(const MCSymbol* Personality_, unsigned PersonalityEncoding_,
1439 unsigned LsdaEncoding_, bool IsSignalFrame_) :
1440 Personality(Personality_), PersonalityEncoding(PersonalityEncoding_),
1441 LsdaEncoding(LsdaEncoding_), IsSignalFrame(IsSignalFrame_) {
1443 const MCSymbol* Personality;
1444 unsigned PersonalityEncoding;
1445 unsigned LsdaEncoding;
1452 struct DenseMapInfo<CIEKey> {
1453 static CIEKey getEmptyKey() {
1454 return CIEKey::getEmptyKey();
1456 static CIEKey getTombstoneKey() {
1457 return CIEKey::getTombstoneKey();
1459 static unsigned getHashValue(const CIEKey &Key) {
1460 return static_cast<unsigned>(hash_combine(Key.Personality,
1461 Key.PersonalityEncoding,
1463 Key.IsSignalFrame));
1465 static bool isEqual(const CIEKey &LHS,
1466 const CIEKey &RHS) {
1467 return LHS.Personality == RHS.Personality &&
1468 LHS.PersonalityEncoding == RHS.PersonalityEncoding &&
1469 LHS.LsdaEncoding == RHS.LsdaEncoding &&
1470 LHS.IsSignalFrame == RHS.IsSignalFrame;
1475 void MCDwarfFrameEmitter::Emit(MCStreamer &Streamer,
1478 MCContext &Context = Streamer.getContext();
1479 MCObjectFileInfo *MOFI =
1480 const_cast<MCObjectFileInfo*>(Context.getObjectFileInfo());
1481 FrameEmitterImpl Emitter(UsingCFI, IsEH);
1482 ArrayRef<MCDwarfFrameInfo> FrameArray = Streamer.getFrameInfos();
1484 // Emit the compact unwind info if available.
1485 if (IsEH && MOFI->getCompactUnwindSection())
1486 for (unsigned i = 0, n = Streamer.getNumFrameInfos(); i < n; ++i) {
1487 const MCDwarfFrameInfo &Frame = Streamer.getFrameInfo(i);
1488 if (Frame.CompactUnwindEncoding)
1489 Emitter.EmitCompactUnwind(Streamer, Frame);
1492 const MCSection &Section = IsEH ? *MOFI->getEHFrameSection() :
1493 *MOFI->getDwarfFrameSection();
1494 Streamer.SwitchSection(&Section);
1495 MCSymbol *SectionStart = Context.CreateTempSymbol();
1496 Streamer.EmitLabel(SectionStart);
1497 Emitter.setSectionStart(SectionStart);
1499 MCSymbol *FDEEnd = NULL;
1500 DenseMap<CIEKey, const MCSymbol*> CIEStarts;
1502 const MCSymbol *DummyDebugKey = NULL;
1503 for (unsigned i = 0, n = FrameArray.size(); i < n; ++i) {
1504 const MCDwarfFrameInfo &Frame = FrameArray[i];
1505 CIEKey Key(Frame.Personality, Frame.PersonalityEncoding,
1506 Frame.LsdaEncoding, Frame.IsSignalFrame);
1507 const MCSymbol *&CIEStart = IsEH ? CIEStarts[Key] : DummyDebugKey;
1509 CIEStart = &Emitter.EmitCIE(Streamer, Frame.Personality,
1510 Frame.PersonalityEncoding, Frame.Lsda,
1511 Frame.IsSignalFrame,
1512 Frame.LsdaEncoding);
1514 FDEEnd = Emitter.EmitFDE(Streamer, *CIEStart, Frame);
1517 Streamer.EmitLabel(FDEEnd);
1520 Streamer.EmitValueToAlignment(Context.getAsmInfo().getPointerSize());
1522 Streamer.EmitLabel(FDEEnd);
1525 void MCDwarfFrameEmitter::EmitAdvanceLoc(MCStreamer &Streamer,
1526 uint64_t AddrDelta) {
1527 SmallString<256> Tmp;
1528 raw_svector_ostream OS(Tmp);
1529 MCDwarfFrameEmitter::EncodeAdvanceLoc(AddrDelta, OS);
1530 Streamer.EmitBytes(OS.str());
1533 void MCDwarfFrameEmitter::EncodeAdvanceLoc(uint64_t AddrDelta,
1535 // FIXME: Assumes the code alignment factor is 1.
1536 if (AddrDelta == 0) {
1537 } else if (isUIntN(6, AddrDelta)) {
1538 uint8_t Opcode = dwarf::DW_CFA_advance_loc | AddrDelta;
1540 } else if (isUInt<8>(AddrDelta)) {
1541 OS << uint8_t(dwarf::DW_CFA_advance_loc1);
1542 OS << uint8_t(AddrDelta);
1543 } else if (isUInt<16>(AddrDelta)) {
1544 // FIXME: check what is the correct behavior on a big endian machine.
1545 OS << uint8_t(dwarf::DW_CFA_advance_loc2);
1546 OS << uint8_t( AddrDelta & 0xff);
1547 OS << uint8_t((AddrDelta >> 8) & 0xff);
1549 // FIXME: check what is the correct behavior on a big endian machine.
1550 assert(isUInt<32>(AddrDelta));
1551 OS << uint8_t(dwarf::DW_CFA_advance_loc4);
1552 OS << uint8_t( AddrDelta & 0xff);
1553 OS << uint8_t((AddrDelta >> 8) & 0xff);
1554 OS << uint8_t((AddrDelta >> 16) & 0xff);
1555 OS << uint8_t((AddrDelta >> 24) & 0xff);