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 // TODO: keep track of the last subsection so that this symbol appears in the
202 MCOS->SwitchSection(Section);
204 MCContext &context = MCOS->getContext();
205 // Create a symbol at the end of the section.
206 MCSymbol *SectionEnd = context.CreateTempSymbol();
207 // Set the value of the symbol, as we are at the end of the section.
208 MCOS->EmitLabel(SectionEnd);
210 // Switch back the dwarf line section.
211 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfLineSection());
213 const MCAsmInfo &asmInfo = MCOS->getContext().getAsmInfo();
214 MCOS->EmitDwarfAdvanceLineAddr(INT64_MAX, LastLabel, SectionEnd,
215 asmInfo.getPointerSize());
219 // This emits the Dwarf file and the line tables.
221 const MCSymbol *MCDwarfFileTable::Emit(MCStreamer *MCOS) {
222 MCContext &context = MCOS->getContext();
223 // Switch to the section where the table will be emitted into.
224 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfLineSection());
226 const DenseMap<unsigned, MCSymbol *> &MCLineTableSymbols =
227 MCOS->getContext().getMCLineTableSymbols();
228 // CUID and MCLineTableSymbols are set in DwarfDebug, when DwarfDebug does
229 // not exist, CUID will be 0 and MCLineTableSymbols will be empty.
230 // Handle Compile Unit 0, the line table start symbol is the section symbol.
231 const MCSymbol *LineStartSym = EmitCU(MCOS, 0);
232 // Handle the rest of the Compile Units.
233 for (unsigned Is = 1, Ie = MCLineTableSymbols.size(); Is < Ie; Is++)
236 // Now delete the MCLineSections that were created in MCLineEntry::Make()
237 // and used to emit the line table.
238 const DenseMap<const MCSection *, MCLineSection *> &MCLineSections =
239 MCOS->getContext().getMCLineSections();
240 for (DenseMap<const MCSection *, MCLineSection *>::const_iterator it =
241 MCLineSections.begin(), ie = MCLineSections.end(); it != ie;
248 const MCSymbol *MCDwarfFileTable::EmitCU(MCStreamer *MCOS, unsigned CUID) {
249 MCContext &context = MCOS->getContext();
251 // Create a symbol at the beginning of the line table.
252 MCSymbol *LineStartSym = MCOS->getContext().getMCLineTableSymbol(CUID);
254 LineStartSym = context.CreateTempSymbol();
255 // Set the value of the symbol, as we are at the start of the line table.
256 MCOS->EmitLabel(LineStartSym);
258 // Create a symbol for the end of the section (to be set when we get there).
259 MCSymbol *LineEndSym = context.CreateTempSymbol();
261 // The first 4 bytes is the total length of the information for this
262 // compilation unit (not including these 4 bytes for the length).
263 MCOS->EmitAbsValue(MakeStartMinusEndExpr(*MCOS, *LineStartSym, *LineEndSym,4),
266 // Next 2 bytes is the Version, which is Dwarf 2.
267 MCOS->EmitIntValue(2, 2);
269 // Create a symbol for the end of the prologue (to be set when we get there).
270 MCSymbol *ProEndSym = context.CreateTempSymbol(); // Lprologue_end
272 // Length of the prologue, is the next 4 bytes. Which is the start of the
273 // section to the end of the prologue. Not including the 4 bytes for the
274 // total length, the 2 bytes for the version, and these 4 bytes for the
275 // length of the prologue.
276 MCOS->EmitAbsValue(MakeStartMinusEndExpr(*MCOS, *LineStartSym, *ProEndSym,
279 // Parameters of the state machine, are next.
280 MCOS->EmitIntValue(DWARF2_LINE_MIN_INSN_LENGTH, 1);
281 MCOS->EmitIntValue(DWARF2_LINE_DEFAULT_IS_STMT, 1);
282 MCOS->EmitIntValue(DWARF2_LINE_BASE, 1);
283 MCOS->EmitIntValue(DWARF2_LINE_RANGE, 1);
284 MCOS->EmitIntValue(DWARF2_LINE_OPCODE_BASE, 1);
286 // Standard opcode lengths
287 MCOS->EmitIntValue(0, 1); // length of DW_LNS_copy
288 MCOS->EmitIntValue(1, 1); // length of DW_LNS_advance_pc
289 MCOS->EmitIntValue(1, 1); // length of DW_LNS_advance_line
290 MCOS->EmitIntValue(1, 1); // length of DW_LNS_set_file
291 MCOS->EmitIntValue(1, 1); // length of DW_LNS_set_column
292 MCOS->EmitIntValue(0, 1); // length of DW_LNS_negate_stmt
293 MCOS->EmitIntValue(0, 1); // length of DW_LNS_set_basic_block
294 MCOS->EmitIntValue(0, 1); // length of DW_LNS_const_add_pc
295 MCOS->EmitIntValue(1, 1); // length of DW_LNS_fixed_advance_pc
296 MCOS->EmitIntValue(0, 1); // length of DW_LNS_set_prologue_end
297 MCOS->EmitIntValue(0, 1); // length of DW_LNS_set_epilogue_begin
298 MCOS->EmitIntValue(1, 1); // DW_LNS_set_isa
300 // Put out the directory and file tables.
302 // First the directory table.
303 const SmallVectorImpl<StringRef> &MCDwarfDirs =
304 context.getMCDwarfDirs(CUID);
305 for (unsigned i = 0; i < MCDwarfDirs.size(); i++) {
306 MCOS->EmitBytes(MCDwarfDirs[i]); // the DirectoryName
307 MCOS->EmitBytes(StringRef("\0", 1)); // the null term. of the string
309 MCOS->EmitIntValue(0, 1); // Terminate the directory list
311 // Second the file table.
312 const SmallVectorImpl<MCDwarfFile *> &MCDwarfFiles =
313 MCOS->getContext().getMCDwarfFiles(CUID);
314 for (unsigned i = 1; i < MCDwarfFiles.size(); i++) {
315 MCOS->EmitBytes(MCDwarfFiles[i]->getName()); // FileName
316 MCOS->EmitBytes(StringRef("\0", 1)); // the null term. of the string
318 MCOS->EmitULEB128IntValue(MCDwarfFiles[i]->getDirIndex());
319 MCOS->EmitIntValue(0, 1); // last modification timestamp (always 0)
320 MCOS->EmitIntValue(0, 1); // filesize (always 0)
322 MCOS->EmitIntValue(0, 1); // Terminate the file list
324 // This is the end of the prologue, so set the value of the symbol at the
325 // end of the prologue (that was used in a previous expression).
326 MCOS->EmitLabel(ProEndSym);
328 // Put out the line tables.
329 const DenseMap<const MCSection *, MCLineSection *> &MCLineSections =
330 MCOS->getContext().getMCLineSections();
331 const std::vector<const MCSection *> &MCLineSectionOrder =
332 MCOS->getContext().getMCLineSectionOrder();
333 for (std::vector<const MCSection*>::const_iterator it =
334 MCLineSectionOrder.begin(), ie = MCLineSectionOrder.end(); it != ie;
336 const MCSection *Sec = *it;
337 const MCLineSection *Line = MCLineSections.lookup(Sec);
338 EmitDwarfLineTable(MCOS, Sec, Line, CUID);
341 if (MCOS->getContext().getAsmInfo().getLinkerRequiresNonEmptyDwarfLines()
342 && MCLineSectionOrder.begin() == MCLineSectionOrder.end()) {
343 // The darwin9 linker has a bug (see PR8715). For for 32-bit architectures
345 // total_length >= prologue_length + 10
346 // We are 4 bytes short, since we have total_length = 51 and
347 // prologue_length = 45
349 // The regular end_sequence should be sufficient.
350 MCDwarfLineAddr::Emit(MCOS, INT64_MAX, 0);
353 // This is the end of the section, so set the value of the symbol at the end
354 // of this section (that was used in a previous expression).
355 MCOS->EmitLabel(LineEndSym);
360 /// Utility function to write the encoding to an object writer.
361 void MCDwarfLineAddr::Write(MCObjectWriter *OW, int64_t LineDelta,
362 uint64_t AddrDelta) {
363 SmallString<256> Tmp;
364 raw_svector_ostream OS(Tmp);
365 MCDwarfLineAddr::Encode(LineDelta, AddrDelta, OS);
366 OW->WriteBytes(OS.str());
369 /// Utility function to emit the encoding to a streamer.
370 void MCDwarfLineAddr::Emit(MCStreamer *MCOS, int64_t LineDelta,
371 uint64_t AddrDelta) {
372 SmallString<256> Tmp;
373 raw_svector_ostream OS(Tmp);
374 MCDwarfLineAddr::Encode(LineDelta, AddrDelta, OS);
375 MCOS->EmitBytes(OS.str());
378 /// Utility function to encode a Dwarf pair of LineDelta and AddrDeltas.
379 void MCDwarfLineAddr::Encode(int64_t LineDelta, uint64_t AddrDelta,
381 uint64_t Temp, Opcode;
382 bool NeedCopy = false;
384 // Scale the address delta by the minimum instruction length.
385 AddrDelta = ScaleAddrDelta(AddrDelta);
387 // A LineDelta of INT64_MAX is a signal that this is actually a
388 // DW_LNE_end_sequence. We cannot use special opcodes here, since we want the
389 // end_sequence to emit the matrix entry.
390 if (LineDelta == INT64_MAX) {
391 if (AddrDelta == MAX_SPECIAL_ADDR_DELTA)
392 OS << char(dwarf::DW_LNS_const_add_pc);
394 OS << char(dwarf::DW_LNS_advance_pc);
395 encodeULEB128(AddrDelta, OS);
397 OS << char(dwarf::DW_LNS_extended_op);
399 OS << char(dwarf::DW_LNE_end_sequence);
403 // Bias the line delta by the base.
404 Temp = LineDelta - DWARF2_LINE_BASE;
406 // If the line increment is out of range of a special opcode, we must encode
407 // it with DW_LNS_advance_line.
408 if (Temp >= DWARF2_LINE_RANGE) {
409 OS << char(dwarf::DW_LNS_advance_line);
410 encodeSLEB128(LineDelta, OS);
413 Temp = 0 - DWARF2_LINE_BASE;
417 // Use DW_LNS_copy instead of a "line +0, addr +0" special opcode.
418 if (LineDelta == 0 && AddrDelta == 0) {
419 OS << char(dwarf::DW_LNS_copy);
423 // Bias the opcode by the special opcode base.
424 Temp += DWARF2_LINE_OPCODE_BASE;
426 // Avoid overflow when addr_delta is large.
427 if (AddrDelta < 256 + MAX_SPECIAL_ADDR_DELTA) {
428 // Try using a special opcode.
429 Opcode = Temp + AddrDelta * DWARF2_LINE_RANGE;
435 // Try using DW_LNS_const_add_pc followed by special op.
436 Opcode = Temp + (AddrDelta - MAX_SPECIAL_ADDR_DELTA) * DWARF2_LINE_RANGE;
438 OS << char(dwarf::DW_LNS_const_add_pc);
444 // Otherwise use DW_LNS_advance_pc.
445 OS << char(dwarf::DW_LNS_advance_pc);
446 encodeULEB128(AddrDelta, OS);
449 OS << char(dwarf::DW_LNS_copy);
454 void MCDwarfFile::print(raw_ostream &OS) const {
455 OS << '"' << getName() << '"';
458 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
459 void MCDwarfFile::dump() const {
464 // Utility function to write a tuple for .debug_abbrev.
465 static void EmitAbbrev(MCStreamer *MCOS, uint64_t Name, uint64_t Form) {
466 MCOS->EmitULEB128IntValue(Name);
467 MCOS->EmitULEB128IntValue(Form);
470 // When generating dwarf for assembly source files this emits
471 // the data for .debug_abbrev section which contains three DIEs.
472 static void EmitGenDwarfAbbrev(MCStreamer *MCOS) {
473 MCContext &context = MCOS->getContext();
474 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfAbbrevSection());
476 // DW_TAG_compile_unit DIE abbrev (1).
477 MCOS->EmitULEB128IntValue(1);
478 MCOS->EmitULEB128IntValue(dwarf::DW_TAG_compile_unit);
479 MCOS->EmitIntValue(dwarf::DW_CHILDREN_yes, 1);
480 EmitAbbrev(MCOS, dwarf::DW_AT_stmt_list, dwarf::DW_FORM_data4);
481 EmitAbbrev(MCOS, dwarf::DW_AT_low_pc, dwarf::DW_FORM_addr);
482 EmitAbbrev(MCOS, dwarf::DW_AT_high_pc, dwarf::DW_FORM_addr);
483 EmitAbbrev(MCOS, dwarf::DW_AT_name, dwarf::DW_FORM_string);
484 EmitAbbrev(MCOS, dwarf::DW_AT_comp_dir, dwarf::DW_FORM_string);
485 StringRef DwarfDebugFlags = context.getDwarfDebugFlags();
486 if (!DwarfDebugFlags.empty())
487 EmitAbbrev(MCOS, dwarf::DW_AT_APPLE_flags, dwarf::DW_FORM_string);
488 EmitAbbrev(MCOS, dwarf::DW_AT_producer, dwarf::DW_FORM_string);
489 EmitAbbrev(MCOS, dwarf::DW_AT_language, dwarf::DW_FORM_data2);
490 EmitAbbrev(MCOS, 0, 0);
492 // DW_TAG_label DIE abbrev (2).
493 MCOS->EmitULEB128IntValue(2);
494 MCOS->EmitULEB128IntValue(dwarf::DW_TAG_label);
495 MCOS->EmitIntValue(dwarf::DW_CHILDREN_yes, 1);
496 EmitAbbrev(MCOS, dwarf::DW_AT_name, dwarf::DW_FORM_string);
497 EmitAbbrev(MCOS, dwarf::DW_AT_decl_file, dwarf::DW_FORM_data4);
498 EmitAbbrev(MCOS, dwarf::DW_AT_decl_line, dwarf::DW_FORM_data4);
499 EmitAbbrev(MCOS, dwarf::DW_AT_low_pc, dwarf::DW_FORM_addr);
500 EmitAbbrev(MCOS, dwarf::DW_AT_prototyped, dwarf::DW_FORM_flag);
501 EmitAbbrev(MCOS, 0, 0);
503 // DW_TAG_unspecified_parameters DIE abbrev (3).
504 MCOS->EmitULEB128IntValue(3);
505 MCOS->EmitULEB128IntValue(dwarf::DW_TAG_unspecified_parameters);
506 MCOS->EmitIntValue(dwarf::DW_CHILDREN_no, 1);
507 EmitAbbrev(MCOS, 0, 0);
509 // Terminate the abbreviations for this compilation unit.
510 MCOS->EmitIntValue(0, 1);
513 // When generating dwarf for assembly source files this emits the data for
514 // .debug_aranges section. Which contains a header and a table of pairs of
515 // PointerSize'ed values for the address and size of section(s) with line table
516 // entries (just the default .text in our case) and a terminating pair of zeros.
517 static void EmitGenDwarfAranges(MCStreamer *MCOS,
518 const MCSymbol *InfoSectionSymbol) {
519 MCContext &context = MCOS->getContext();
521 // Create a symbol at the end of the section that we are creating the dwarf
522 // debugging info to use later in here as part of the expression to calculate
523 // the size of the section for the table.
524 MCOS->SwitchSection(context.getGenDwarfSection());
525 MCSymbol *SectionEndSym = context.CreateTempSymbol();
526 MCOS->EmitLabel(SectionEndSym);
527 context.setGenDwarfSectionEndSym(SectionEndSym);
529 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfARangesSection());
531 // This will be the length of the .debug_aranges section, first account for
532 // the size of each item in the header (see below where we emit these items).
533 int Length = 4 + 2 + 4 + 1 + 1;
535 // Figure the padding after the header before the table of address and size
536 // pairs who's values are PointerSize'ed.
537 const MCAsmInfo &asmInfo = context.getAsmInfo();
538 int AddrSize = asmInfo.getPointerSize();
539 int Pad = 2 * AddrSize - (Length & (2 * AddrSize - 1));
540 if (Pad == 2 * AddrSize)
544 // Add the size of the pair of PointerSize'ed values for the address and size
545 // of the one default .text section we have in the table.
546 Length += 2 * AddrSize;
547 // And the pair of terminating zeros.
548 Length += 2 * AddrSize;
551 // Emit the header for this section.
552 // The 4 byte length not including the 4 byte value for the length.
553 MCOS->EmitIntValue(Length - 4, 4);
554 // The 2 byte version, which is 2.
555 MCOS->EmitIntValue(2, 2);
556 // The 4 byte offset to the compile unit in the .debug_info from the start
557 // of the .debug_info.
558 if (InfoSectionSymbol)
559 MCOS->EmitSymbolValue(InfoSectionSymbol, 4);
561 MCOS->EmitIntValue(0, 4);
562 // The 1 byte size of an address.
563 MCOS->EmitIntValue(AddrSize, 1);
564 // The 1 byte size of a segment descriptor, we use a value of zero.
565 MCOS->EmitIntValue(0, 1);
566 // Align the header with the padding if needed, before we put out the table.
567 for(int i = 0; i < Pad; i++)
568 MCOS->EmitIntValue(0, 1);
570 // Now emit the table of pairs of PointerSize'ed values for the section(s)
571 // address and size, in our case just the one default .text section.
572 const MCExpr *Addr = MCSymbolRefExpr::Create(
573 context.getGenDwarfSectionStartSym(), MCSymbolRefExpr::VK_None, context);
574 const MCExpr *Size = MakeStartMinusEndExpr(*MCOS,
575 *context.getGenDwarfSectionStartSym(), *SectionEndSym, 0);
576 MCOS->EmitAbsValue(Addr, AddrSize);
577 MCOS->EmitAbsValue(Size, AddrSize);
579 // And finally the pair of terminating zeros.
580 MCOS->EmitIntValue(0, AddrSize);
581 MCOS->EmitIntValue(0, AddrSize);
584 // When generating dwarf for assembly source files this emits the data for
585 // .debug_info section which contains three parts. The header, the compile_unit
586 // DIE and a list of label DIEs.
587 static void EmitGenDwarfInfo(MCStreamer *MCOS,
588 const MCSymbol *AbbrevSectionSymbol,
589 const MCSymbol *LineSectionSymbol) {
590 MCContext &context = MCOS->getContext();
592 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfInfoSection());
594 // Create a symbol at the start and end of this section used in here for the
595 // expression to calculate the length in the header.
596 MCSymbol *InfoStart = context.CreateTempSymbol();
597 MCOS->EmitLabel(InfoStart);
598 MCSymbol *InfoEnd = context.CreateTempSymbol();
600 // First part: the header.
602 // The 4 byte total length of the information for this compilation unit, not
603 // including these 4 bytes.
604 const MCExpr *Length = MakeStartMinusEndExpr(*MCOS, *InfoStart, *InfoEnd, 4);
605 MCOS->EmitAbsValue(Length, 4);
607 // The 2 byte DWARF version, which is 2.
608 MCOS->EmitIntValue(2, 2);
610 // The 4 byte offset to the debug abbrevs from the start of the .debug_abbrev,
611 // it is at the start of that section so this is zero.
612 if (AbbrevSectionSymbol) {
613 MCOS->EmitSymbolValue(AbbrevSectionSymbol, 4);
615 MCOS->EmitIntValue(0, 4);
618 const MCAsmInfo &asmInfo = context.getAsmInfo();
619 int AddrSize = asmInfo.getPointerSize();
620 // The 1 byte size of an address.
621 MCOS->EmitIntValue(AddrSize, 1);
623 // Second part: the compile_unit DIE.
625 // The DW_TAG_compile_unit DIE abbrev (1).
626 MCOS->EmitULEB128IntValue(1);
628 // DW_AT_stmt_list, a 4 byte offset from the start of the .debug_line section,
629 // which is at the start of that section so this is zero.
630 if (LineSectionSymbol) {
631 MCOS->EmitSymbolValue(LineSectionSymbol, 4);
633 MCOS->EmitIntValue(0, 4);
636 // AT_low_pc, the first address of the default .text section.
637 const MCExpr *Start = MCSymbolRefExpr::Create(
638 context.getGenDwarfSectionStartSym(), MCSymbolRefExpr::VK_None, context);
639 MCOS->EmitAbsValue(Start, AddrSize);
641 // AT_high_pc, the last address of the default .text section.
642 const MCExpr *End = MCSymbolRefExpr::Create(
643 context.getGenDwarfSectionEndSym(), MCSymbolRefExpr::VK_None, context);
644 MCOS->EmitAbsValue(End, AddrSize);
646 // AT_name, the name of the source file. Reconstruct from the first directory
647 // and file table entries.
648 const SmallVectorImpl<StringRef> &MCDwarfDirs =
649 context.getMCDwarfDirs();
650 if (MCDwarfDirs.size() > 0) {
651 MCOS->EmitBytes(MCDwarfDirs[0]);
652 MCOS->EmitBytes("/");
654 const SmallVectorImpl<MCDwarfFile *> &MCDwarfFiles =
655 MCOS->getContext().getMCDwarfFiles();
656 MCOS->EmitBytes(MCDwarfFiles[1]->getName());
657 MCOS->EmitIntValue(0, 1); // NULL byte to terminate the string.
659 // AT_comp_dir, the working directory the assembly was done in.
660 MCOS->EmitBytes(context.getCompilationDir());
661 MCOS->EmitIntValue(0, 1); // NULL byte to terminate the string.
663 // AT_APPLE_flags, the command line arguments of the assembler tool.
664 StringRef DwarfDebugFlags = context.getDwarfDebugFlags();
665 if (!DwarfDebugFlags.empty()){
666 MCOS->EmitBytes(DwarfDebugFlags);
667 MCOS->EmitIntValue(0, 1); // NULL byte to terminate the string.
670 // AT_producer, the version of the assembler tool.
671 StringRef DwarfDebugProducer = context.getDwarfDebugProducer();
672 if (!DwarfDebugProducer.empty()){
673 MCOS->EmitBytes(DwarfDebugProducer);
676 MCOS->EmitBytes(StringRef("llvm-mc (based on LLVM "));
677 MCOS->EmitBytes(StringRef(PACKAGE_VERSION));
678 MCOS->EmitBytes(StringRef(")"));
680 MCOS->EmitIntValue(0, 1); // NULL byte to terminate the string.
682 // AT_language, a 4 byte value. We use DW_LANG_Mips_Assembler as the dwarf2
683 // draft has no standard code for assembler.
684 MCOS->EmitIntValue(dwarf::DW_LANG_Mips_Assembler, 2);
686 // Third part: the list of label DIEs.
688 // Loop on saved info for dwarf labels and create the DIEs for them.
689 const std::vector<const MCGenDwarfLabelEntry *> &Entries =
690 MCOS->getContext().getMCGenDwarfLabelEntries();
691 for (std::vector<const MCGenDwarfLabelEntry *>::const_iterator it =
692 Entries.begin(), ie = Entries.end(); it != ie;
694 const MCGenDwarfLabelEntry *Entry = *it;
696 // The DW_TAG_label DIE abbrev (2).
697 MCOS->EmitULEB128IntValue(2);
699 // AT_name, of the label without any leading underbar.
700 MCOS->EmitBytes(Entry->getName());
701 MCOS->EmitIntValue(0, 1); // NULL byte to terminate the string.
703 // AT_decl_file, index into the file table.
704 MCOS->EmitIntValue(Entry->getFileNumber(), 4);
706 // AT_decl_line, source line number.
707 MCOS->EmitIntValue(Entry->getLineNumber(), 4);
709 // AT_low_pc, start address of the label.
710 const MCExpr *AT_low_pc = MCSymbolRefExpr::Create(Entry->getLabel(),
711 MCSymbolRefExpr::VK_None, context);
712 MCOS->EmitAbsValue(AT_low_pc, AddrSize);
714 // DW_AT_prototyped, a one byte flag value of 0 saying we have no prototype.
715 MCOS->EmitIntValue(0, 1);
717 // The DW_TAG_unspecified_parameters DIE abbrev (3).
718 MCOS->EmitULEB128IntValue(3);
720 // Add the NULL DIE terminating the DW_TAG_unspecified_parameters DIE's.
721 MCOS->EmitIntValue(0, 1);
723 // Deallocate the MCGenDwarfLabelEntry classes that saved away the info
724 // for the dwarf labels.
725 for (std::vector<const MCGenDwarfLabelEntry *>::const_iterator it =
726 Entries.begin(), ie = Entries.end(); it != ie;
728 const MCGenDwarfLabelEntry *Entry = *it;
732 // Add the NULL DIE terminating the Compile Unit DIE's.
733 MCOS->EmitIntValue(0, 1);
735 // Now set the value of the symbol at the end of the info section.
736 MCOS->EmitLabel(InfoEnd);
740 // When generating dwarf for assembly source files this emits the Dwarf
743 void MCGenDwarfInfo::Emit(MCStreamer *MCOS, const MCSymbol *LineSectionSymbol) {
744 // Create the dwarf sections in this order (.debug_line already created).
745 MCContext &context = MCOS->getContext();
746 const MCAsmInfo &AsmInfo = context.getAsmInfo();
747 bool CreateDwarfSectionSymbols =
748 AsmInfo.doesDwarfUseRelocationsAcrossSections();
749 if (!CreateDwarfSectionSymbols)
750 LineSectionSymbol = NULL;
751 MCSymbol *AbbrevSectionSymbol = NULL;
752 MCSymbol *InfoSectionSymbol = NULL;
753 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfInfoSection());
754 if (CreateDwarfSectionSymbols) {
755 InfoSectionSymbol = context.CreateTempSymbol();
756 MCOS->EmitLabel(InfoSectionSymbol);
758 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfAbbrevSection());
759 if (CreateDwarfSectionSymbols) {
760 AbbrevSectionSymbol = context.CreateTempSymbol();
761 MCOS->EmitLabel(AbbrevSectionSymbol);
763 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfARangesSection());
765 // If there are no line table entries then do not emit any section contents.
766 if (context.getMCLineSections().empty())
769 // Output the data for .debug_aranges section.
770 EmitGenDwarfAranges(MCOS, InfoSectionSymbol);
772 // Output the data for .debug_abbrev section.
773 EmitGenDwarfAbbrev(MCOS);
775 // Output the data for .debug_info section.
776 EmitGenDwarfInfo(MCOS, AbbrevSectionSymbol, LineSectionSymbol);
780 // When generating dwarf for assembly source files this is called when symbol
781 // for a label is created. If this symbol is not a temporary and is in the
782 // section that dwarf is being generated for, save the needed info to create
785 void MCGenDwarfLabelEntry::Make(MCSymbol *Symbol, MCStreamer *MCOS,
786 SourceMgr &SrcMgr, SMLoc &Loc) {
787 // We won't create dwarf labels for temporary symbols or symbols not in
789 if (Symbol->isTemporary())
791 MCContext &context = MCOS->getContext();
792 if (context.getGenDwarfSection() != MCOS->getCurrentSection().first)
795 // The dwarf label's name does not have the symbol name's leading
797 StringRef Name = Symbol->getName();
798 if (Name.startswith("_"))
799 Name = Name.substr(1, Name.size()-1);
801 // Get the dwarf file number to be used for the dwarf label.
802 unsigned FileNumber = context.getGenDwarfFileNumber();
804 // Finding the line number is the expensive part which is why we just don't
805 // pass it in as for some symbols we won't create a dwarf label.
806 int CurBuffer = SrcMgr.FindBufferContainingLoc(Loc);
807 unsigned LineNumber = SrcMgr.FindLineNumber(Loc, CurBuffer);
809 // We create a temporary symbol for use for the AT_high_pc and AT_low_pc
810 // values so that they don't have things like an ARM thumb bit from the
811 // original symbol. So when used they won't get a low bit set after
813 MCSymbol *Label = context.CreateTempSymbol();
814 MCOS->EmitLabel(Label);
816 // Create and entry for the info and add it to the other entries.
817 MCGenDwarfLabelEntry *Entry =
818 new MCGenDwarfLabelEntry(Name, FileNumber, LineNumber, Label);
819 MCOS->getContext().addMCGenDwarfLabelEntry(Entry);
822 static int getDataAlignmentFactor(MCStreamer &streamer) {
823 MCContext &context = streamer.getContext();
824 const MCAsmInfo &asmInfo = context.getAsmInfo();
825 int size = asmInfo.getCalleeSaveStackSlotSize();
826 if (asmInfo.isStackGrowthDirectionUp())
832 static unsigned getSizeForEncoding(MCStreamer &streamer,
833 unsigned symbolEncoding) {
834 MCContext &context = streamer.getContext();
835 unsigned format = symbolEncoding & 0x0f;
837 default: llvm_unreachable("Unknown Encoding");
838 case dwarf::DW_EH_PE_absptr:
839 case dwarf::DW_EH_PE_signed:
840 return context.getAsmInfo().getPointerSize();
841 case dwarf::DW_EH_PE_udata2:
842 case dwarf::DW_EH_PE_sdata2:
844 case dwarf::DW_EH_PE_udata4:
845 case dwarf::DW_EH_PE_sdata4:
847 case dwarf::DW_EH_PE_udata8:
848 case dwarf::DW_EH_PE_sdata8:
853 static void EmitSymbol(MCStreamer &streamer, const MCSymbol &symbol,
854 unsigned symbolEncoding, const char *comment = 0) {
855 MCContext &context = streamer.getContext();
856 const MCAsmInfo &asmInfo = context.getAsmInfo();
857 const MCExpr *v = asmInfo.getExprForFDESymbol(&symbol,
860 unsigned size = getSizeForEncoding(streamer, symbolEncoding);
861 if (streamer.isVerboseAsm() && comment) streamer.AddComment(comment);
862 streamer.EmitAbsValue(v, size);
865 static void EmitPersonality(MCStreamer &streamer, const MCSymbol &symbol,
866 unsigned symbolEncoding) {
867 MCContext &context = streamer.getContext();
868 const MCAsmInfo &asmInfo = context.getAsmInfo();
869 const MCExpr *v = asmInfo.getExprForPersonalitySymbol(&symbol,
872 unsigned size = getSizeForEncoding(streamer, symbolEncoding);
873 streamer.EmitValue(v, size);
876 static const MachineLocation TranslateMachineLocation(
877 const MCRegisterInfo &MRI,
878 const MachineLocation &Loc) {
879 unsigned Reg = Loc.getReg() == MachineLocation::VirtualFP ?
880 MachineLocation::VirtualFP :
881 unsigned(MRI.getDwarfRegNum(Loc.getReg(), true));
882 const MachineLocation &NewLoc = Loc.isReg() ?
883 MachineLocation(Reg) : MachineLocation(Reg, Loc.getOffset());
888 class FrameEmitterImpl {
893 const MCSymbol *SectionStart;
895 FrameEmitterImpl(bool usingCFI, bool isEH)
896 : CFAOffset(0), CIENum(0), UsingCFI(usingCFI), IsEH(isEH),
899 void setSectionStart(const MCSymbol *Label) { SectionStart = Label; }
901 /// EmitCompactUnwind - Emit the unwind information in a compact way. If
902 /// we're successful, return 'true'. Otherwise, return 'false' and it will
903 /// emit the normal CIE and FDE.
904 void EmitCompactUnwind(MCStreamer &streamer,
905 const MCDwarfFrameInfo &frame);
907 const MCSymbol &EmitCIE(MCStreamer &streamer,
908 const MCSymbol *personality,
909 unsigned personalityEncoding,
910 const MCSymbol *lsda,
912 unsigned lsdaEncoding);
913 MCSymbol *EmitFDE(MCStreamer &streamer,
914 const MCSymbol &cieStart,
915 const MCDwarfFrameInfo &frame);
916 void EmitCFIInstructions(MCStreamer &streamer,
917 const std::vector<MCCFIInstruction> &Instrs,
918 MCSymbol *BaseLabel);
919 void EmitCFIInstruction(MCStreamer &Streamer,
920 const MCCFIInstruction &Instr);
923 } // end anonymous namespace
925 static void EmitEncodingByte(MCStreamer &Streamer, unsigned Encoding,
927 if (Streamer.isVerboseAsm()) {
930 default: EncStr = "<unknown encoding>"; break;
931 case dwarf::DW_EH_PE_absptr: EncStr = "absptr"; break;
932 case dwarf::DW_EH_PE_omit: EncStr = "omit"; break;
933 case dwarf::DW_EH_PE_pcrel: EncStr = "pcrel"; break;
934 case dwarf::DW_EH_PE_udata4: EncStr = "udata4"; break;
935 case dwarf::DW_EH_PE_udata8: EncStr = "udata8"; break;
936 case dwarf::DW_EH_PE_sdata4: EncStr = "sdata4"; break;
937 case dwarf::DW_EH_PE_sdata8: EncStr = "sdata8"; break;
938 case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata4:
939 EncStr = "pcrel udata4";
941 case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4:
942 EncStr = "pcrel sdata4";
944 case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata8:
945 EncStr = "pcrel udata8";
947 case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata8:
948 EncStr = "screl sdata8";
950 case dwarf::DW_EH_PE_indirect |dwarf::DW_EH_PE_pcrel|dwarf::DW_EH_PE_udata4:
951 EncStr = "indirect pcrel udata4";
953 case dwarf::DW_EH_PE_indirect |dwarf::DW_EH_PE_pcrel|dwarf::DW_EH_PE_sdata4:
954 EncStr = "indirect pcrel sdata4";
956 case dwarf::DW_EH_PE_indirect |dwarf::DW_EH_PE_pcrel|dwarf::DW_EH_PE_udata8:
957 EncStr = "indirect pcrel udata8";
959 case dwarf::DW_EH_PE_indirect |dwarf::DW_EH_PE_pcrel|dwarf::DW_EH_PE_sdata8:
960 EncStr = "indirect pcrel sdata8";
964 Streamer.AddComment(Twine(Prefix) + " = " + EncStr);
967 Streamer.EmitIntValue(Encoding, 1);
970 void FrameEmitterImpl::EmitCFIInstruction(MCStreamer &Streamer,
971 const MCCFIInstruction &Instr) {
972 int dataAlignmentFactor = getDataAlignmentFactor(Streamer);
973 bool VerboseAsm = Streamer.isVerboseAsm();
975 switch (Instr.getOperation()) {
976 case MCCFIInstruction::OpRegister: {
977 unsigned Reg1 = Instr.getRegister();
978 unsigned Reg2 = Instr.getRegister2();
980 Streamer.AddComment("DW_CFA_register");
981 Streamer.AddComment(Twine("Reg1 ") + Twine(Reg1));
982 Streamer.AddComment(Twine("Reg2 ") + Twine(Reg2));
984 Streamer.EmitIntValue(dwarf::DW_CFA_register, 1);
985 Streamer.EmitULEB128IntValue(Reg1);
986 Streamer.EmitULEB128IntValue(Reg2);
989 case MCCFIInstruction::OpUndefined: {
990 unsigned Reg = Instr.getRegister();
992 Streamer.AddComment("DW_CFA_undefined");
993 Streamer.AddComment(Twine("Reg ") + Twine(Reg));
995 Streamer.EmitIntValue(dwarf::DW_CFA_undefined, 1);
996 Streamer.EmitULEB128IntValue(Reg);
999 case MCCFIInstruction::OpAdjustCfaOffset:
1000 case MCCFIInstruction::OpDefCfaOffset: {
1001 const bool IsRelative =
1002 Instr.getOperation() == MCCFIInstruction::OpAdjustCfaOffset;
1005 Streamer.AddComment("DW_CFA_def_cfa_offset");
1006 Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa_offset, 1);
1009 CFAOffset += Instr.getOffset();
1011 CFAOffset = -Instr.getOffset();
1014 Streamer.AddComment(Twine("Offset " + Twine(CFAOffset)));
1015 Streamer.EmitULEB128IntValue(CFAOffset);
1019 case MCCFIInstruction::OpDefCfa: {
1021 Streamer.AddComment("DW_CFA_def_cfa");
1022 Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa, 1);
1025 Streamer.AddComment(Twine("Reg ") + Twine(Instr.getRegister()));
1026 Streamer.EmitULEB128IntValue(Instr.getRegister());
1028 CFAOffset = -Instr.getOffset();
1031 Streamer.AddComment(Twine("Offset " + Twine(CFAOffset)));
1032 Streamer.EmitULEB128IntValue(CFAOffset);
1037 case MCCFIInstruction::OpDefCfaRegister: {
1039 Streamer.AddComment("DW_CFA_def_cfa_register");
1040 Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa_register, 1);
1043 Streamer.AddComment(Twine("Reg ") + Twine(Instr.getRegister()));
1044 Streamer.EmitULEB128IntValue(Instr.getRegister());
1049 case MCCFIInstruction::OpOffset:
1050 case MCCFIInstruction::OpRelOffset: {
1051 const bool IsRelative =
1052 Instr.getOperation() == MCCFIInstruction::OpRelOffset;
1054 unsigned Reg = Instr.getRegister();
1055 int Offset = Instr.getOffset();
1057 Offset -= CFAOffset;
1058 Offset = Offset / dataAlignmentFactor;
1061 if (VerboseAsm) Streamer.AddComment("DW_CFA_offset_extended_sf");
1062 Streamer.EmitIntValue(dwarf::DW_CFA_offset_extended_sf, 1);
1063 if (VerboseAsm) Streamer.AddComment(Twine("Reg ") + Twine(Reg));
1064 Streamer.EmitULEB128IntValue(Reg);
1065 if (VerboseAsm) Streamer.AddComment(Twine("Offset ") + Twine(Offset));
1066 Streamer.EmitSLEB128IntValue(Offset);
1067 } else if (Reg < 64) {
1068 if (VerboseAsm) Streamer.AddComment(Twine("DW_CFA_offset + Reg(") +
1070 Streamer.EmitIntValue(dwarf::DW_CFA_offset + Reg, 1);
1071 if (VerboseAsm) Streamer.AddComment(Twine("Offset ") + Twine(Offset));
1072 Streamer.EmitULEB128IntValue(Offset);
1074 if (VerboseAsm) Streamer.AddComment("DW_CFA_offset_extended");
1075 Streamer.EmitIntValue(dwarf::DW_CFA_offset_extended, 1);
1076 if (VerboseAsm) Streamer.AddComment(Twine("Reg ") + Twine(Reg));
1077 Streamer.EmitULEB128IntValue(Reg);
1078 if (VerboseAsm) Streamer.AddComment(Twine("Offset ") + Twine(Offset));
1079 Streamer.EmitULEB128IntValue(Offset);
1083 case MCCFIInstruction::OpRememberState:
1084 if (VerboseAsm) Streamer.AddComment("DW_CFA_remember_state");
1085 Streamer.EmitIntValue(dwarf::DW_CFA_remember_state, 1);
1087 case MCCFIInstruction::OpRestoreState:
1088 if (VerboseAsm) Streamer.AddComment("DW_CFA_restore_state");
1089 Streamer.EmitIntValue(dwarf::DW_CFA_restore_state, 1);
1091 case MCCFIInstruction::OpSameValue: {
1092 unsigned Reg = Instr.getRegister();
1093 if (VerboseAsm) Streamer.AddComment("DW_CFA_same_value");
1094 Streamer.EmitIntValue(dwarf::DW_CFA_same_value, 1);
1095 if (VerboseAsm) Streamer.AddComment(Twine("Reg ") + Twine(Reg));
1096 Streamer.EmitULEB128IntValue(Reg);
1099 case MCCFIInstruction::OpRestore: {
1100 unsigned Reg = Instr.getRegister();
1102 Streamer.AddComment("DW_CFA_restore");
1103 Streamer.AddComment(Twine("Reg ") + Twine(Reg));
1105 Streamer.EmitIntValue(dwarf::DW_CFA_restore | Reg, 1);
1108 case MCCFIInstruction::OpEscape:
1109 if (VerboseAsm) Streamer.AddComment("Escape bytes");
1110 Streamer.EmitBytes(Instr.getValues());
1113 llvm_unreachable("Unhandled case in switch");
1116 /// EmitFrameMoves - Emit frame instructions to describe the layout of the
1118 void FrameEmitterImpl::EmitCFIInstructions(MCStreamer &streamer,
1119 const std::vector<MCCFIInstruction> &Instrs,
1120 MCSymbol *BaseLabel) {
1121 for (unsigned i = 0, N = Instrs.size(); i < N; ++i) {
1122 const MCCFIInstruction &Instr = Instrs[i];
1123 MCSymbol *Label = Instr.getLabel();
1124 // Throw out move if the label is invalid.
1125 if (Label && !Label->isDefined()) continue; // Not emitted, in dead code.
1127 // Advance row if new location.
1128 if (BaseLabel && Label) {
1129 MCSymbol *ThisSym = Label;
1130 if (ThisSym != BaseLabel) {
1131 if (streamer.isVerboseAsm()) streamer.AddComment("DW_CFA_advance_loc4");
1132 streamer.EmitDwarfAdvanceFrameAddr(BaseLabel, ThisSym);
1133 BaseLabel = ThisSym;
1137 EmitCFIInstruction(streamer, Instr);
1141 /// EmitCompactUnwind - Emit the unwind information in a compact way. If we're
1142 /// successful, return 'true'. Otherwise, return 'false' and it will emit the
1143 /// normal CIE and FDE.
1144 void FrameEmitterImpl::EmitCompactUnwind(MCStreamer &Streamer,
1145 const MCDwarfFrameInfo &Frame) {
1146 MCContext &Context = Streamer.getContext();
1147 const MCObjectFileInfo *MOFI = Context.getObjectFileInfo();
1148 bool VerboseAsm = Streamer.isVerboseAsm();
1150 // range-start range-length compact-unwind-enc personality-func lsda
1151 // _foo LfooEnd-_foo 0x00000023 0 0
1152 // _bar LbarEnd-_bar 0x00000025 __gxx_personality except_tab1
1154 // .section __LD,__compact_unwind,regular,debug
1156 // # compact unwind for _foo
1158 // .set L1,LfooEnd-_foo
1164 // # compact unwind for _bar
1166 // .set L2,LbarEnd-_bar
1169 // .quad __gxx_personality
1170 // .quad except_tab1
1172 uint32_t Encoding = Frame.CompactUnwindEncoding;
1173 if (!Encoding) return;
1175 bool DwarfEHFrameOnly = (Encoding == MOFI->getCompactUnwindDwarfEHFrameOnly());
1177 // The encoding needs to know we have an LSDA.
1178 if (!DwarfEHFrameOnly && Frame.Lsda)
1179 Encoding |= 0x40000000;
1181 Streamer.SwitchSection(MOFI->getCompactUnwindSection());
1184 unsigned FDEEncoding = MOFI->getFDEEncoding(UsingCFI);
1185 unsigned Size = getSizeForEncoding(Streamer, FDEEncoding);
1186 if (VerboseAsm) Streamer.AddComment("Range Start");
1187 Streamer.EmitSymbolValue(Frame.Function, Size);
1190 const MCExpr *Range = MakeStartMinusEndExpr(Streamer, *Frame.Begin,
1192 if (VerboseAsm) Streamer.AddComment("Range Length");
1193 Streamer.EmitAbsValue(Range, 4);
1196 Size = getSizeForEncoding(Streamer, dwarf::DW_EH_PE_udata4);
1197 if (VerboseAsm) Streamer.AddComment("Compact Unwind Encoding: 0x" +
1198 Twine::utohexstr(Encoding));
1199 Streamer.EmitIntValue(Encoding, Size);
1201 // Personality Function
1202 Size = getSizeForEncoding(Streamer, dwarf::DW_EH_PE_absptr);
1203 if (VerboseAsm) Streamer.AddComment("Personality Function");
1204 if (!DwarfEHFrameOnly && Frame.Personality)
1205 Streamer.EmitSymbolValue(Frame.Personality, Size);
1207 Streamer.EmitIntValue(0, Size); // No personality fn
1210 Size = getSizeForEncoding(Streamer, Frame.LsdaEncoding);
1211 if (VerboseAsm) Streamer.AddComment("LSDA");
1212 if (!DwarfEHFrameOnly && Frame.Lsda)
1213 Streamer.EmitSymbolValue(Frame.Lsda, Size);
1215 Streamer.EmitIntValue(0, Size); // No LSDA
1218 const MCSymbol &FrameEmitterImpl::EmitCIE(MCStreamer &streamer,
1219 const MCSymbol *personality,
1220 unsigned personalityEncoding,
1221 const MCSymbol *lsda,
1223 unsigned lsdaEncoding) {
1224 MCContext &context = streamer.getContext();
1225 const MCRegisterInfo &MRI = context.getRegisterInfo();
1226 const MCObjectFileInfo *MOFI = context.getObjectFileInfo();
1227 bool verboseAsm = streamer.isVerboseAsm();
1229 MCSymbol *sectionStart;
1230 if (MOFI->isFunctionEHFrameSymbolPrivate() || !IsEH)
1231 sectionStart = context.CreateTempSymbol();
1233 sectionStart = context.GetOrCreateSymbol(Twine("EH_frame") + Twine(CIENum));
1235 streamer.EmitLabel(sectionStart);
1238 MCSymbol *sectionEnd = context.CreateTempSymbol();
1241 const MCExpr *Length = MakeStartMinusEndExpr(streamer, *sectionStart,
1243 if (verboseAsm) streamer.AddComment("CIE Length");
1244 streamer.EmitAbsValue(Length, 4);
1247 unsigned CIE_ID = IsEH ? 0 : -1;
1248 if (verboseAsm) streamer.AddComment("CIE ID Tag");
1249 streamer.EmitIntValue(CIE_ID, 4);
1252 if (verboseAsm) streamer.AddComment("DW_CIE_VERSION");
1253 streamer.EmitIntValue(dwarf::DW_CIE_VERSION, 1);
1255 // Augmentation String
1256 SmallString<8> Augmentation;
1258 if (verboseAsm) streamer.AddComment("CIE Augmentation");
1259 Augmentation += "z";
1261 Augmentation += "P";
1263 Augmentation += "L";
1264 Augmentation += "R";
1266 Augmentation += "S";
1267 streamer.EmitBytes(Augmentation.str());
1269 streamer.EmitIntValue(0, 1);
1271 // Code Alignment Factor
1272 if (verboseAsm) streamer.AddComment("CIE Code Alignment Factor");
1273 streamer.EmitULEB128IntValue(1);
1275 // Data Alignment Factor
1276 if (verboseAsm) streamer.AddComment("CIE Data Alignment Factor");
1277 streamer.EmitSLEB128IntValue(getDataAlignmentFactor(streamer));
1279 // Return Address Register
1280 if (verboseAsm) streamer.AddComment("CIE Return Address Column");
1281 streamer.EmitULEB128IntValue(MRI.getDwarfRegNum(MRI.getRARegister(), true));
1283 // Augmentation Data Length (optional)
1285 unsigned augmentationLength = 0;
1288 // Personality Encoding
1289 augmentationLength += 1;
1291 augmentationLength += getSizeForEncoding(streamer, personalityEncoding);
1294 augmentationLength += 1;
1295 // Encoding of the FDE pointers
1296 augmentationLength += 1;
1298 if (verboseAsm) streamer.AddComment("Augmentation Size");
1299 streamer.EmitULEB128IntValue(augmentationLength);
1301 // Augmentation Data (optional)
1303 // Personality Encoding
1304 EmitEncodingByte(streamer, personalityEncoding,
1305 "Personality Encoding");
1307 if (verboseAsm) streamer.AddComment("Personality");
1308 EmitPersonality(streamer, *personality, personalityEncoding);
1312 EmitEncodingByte(streamer, lsdaEncoding, "LSDA Encoding");
1314 // Encoding of the FDE pointers
1315 EmitEncodingByte(streamer, MOFI->getFDEEncoding(UsingCFI),
1319 // Initial Instructions
1321 const MCAsmInfo &MAI = context.getAsmInfo();
1322 const std::vector<MachineMove> &Moves = MAI.getInitialFrameState();
1323 std::vector<MCCFIInstruction> Instructions;
1325 for (int i = 0, n = Moves.size(); i != n; ++i) {
1326 MCSymbol *Label = Moves[i].getLabel();
1327 const MachineLocation &Dst =
1328 TranslateMachineLocation(MRI, Moves[i].getDestination());
1329 const MachineLocation &Src =
1330 TranslateMachineLocation(MRI, Moves[i].getSource());
1333 assert(Dst.getReg() == MachineLocation::VirtualFP);
1334 assert(!Src.isReg());
1335 MCCFIInstruction Inst =
1336 MCCFIInstruction::createDefCfa(Label, Src.getReg(), -Src.getOffset());
1337 Instructions.push_back(Inst);
1339 assert(Src.isReg());
1340 unsigned Reg = Src.getReg();
1341 int Offset = Dst.getOffset();
1342 MCCFIInstruction Inst =
1343 MCCFIInstruction::createOffset(Label, Reg, Offset);
1344 Instructions.push_back(Inst);
1348 EmitCFIInstructions(streamer, Instructions, NULL);
1351 streamer.EmitValueToAlignment(IsEH
1352 ? 4 : context.getAsmInfo().getPointerSize());
1354 streamer.EmitLabel(sectionEnd);
1355 return *sectionStart;
1358 MCSymbol *FrameEmitterImpl::EmitFDE(MCStreamer &streamer,
1359 const MCSymbol &cieStart,
1360 const MCDwarfFrameInfo &frame) {
1361 MCContext &context = streamer.getContext();
1362 MCSymbol *fdeStart = context.CreateTempSymbol();
1363 MCSymbol *fdeEnd = context.CreateTempSymbol();
1364 const MCObjectFileInfo *MOFI = context.getObjectFileInfo();
1365 bool verboseAsm = streamer.isVerboseAsm();
1367 if (IsEH && frame.Function && !MOFI->isFunctionEHFrameSymbolPrivate()) {
1369 context.GetOrCreateSymbol(frame.Function->getName() + Twine(".eh"));
1370 streamer.EmitEHSymAttributes(frame.Function, EHSym);
1371 streamer.EmitLabel(EHSym);
1375 const MCExpr *Length = MakeStartMinusEndExpr(streamer, *fdeStart, *fdeEnd, 0);
1376 if (verboseAsm) streamer.AddComment("FDE Length");
1377 streamer.EmitAbsValue(Length, 4);
1379 streamer.EmitLabel(fdeStart);
1382 const MCAsmInfo &asmInfo = context.getAsmInfo();
1384 const MCExpr *offset = MakeStartMinusEndExpr(streamer, cieStart, *fdeStart,
1386 if (verboseAsm) streamer.AddComment("FDE CIE Offset");
1387 streamer.EmitAbsValue(offset, 4);
1388 } else if (!asmInfo.doesDwarfUseRelocationsAcrossSections()) {
1389 const MCExpr *offset = MakeStartMinusEndExpr(streamer, *SectionStart,
1391 streamer.EmitAbsValue(offset, 4);
1393 streamer.EmitSymbolValue(&cieStart, 4);
1397 unsigned PCEncoding = IsEH ? MOFI->getFDEEncoding(UsingCFI)
1398 : (unsigned)dwarf::DW_EH_PE_absptr;
1399 unsigned PCSize = getSizeForEncoding(streamer, PCEncoding);
1400 EmitSymbol(streamer, *frame.Begin, PCEncoding, "FDE initial location");
1403 const MCExpr *Range = MakeStartMinusEndExpr(streamer, *frame.Begin,
1405 if (verboseAsm) streamer.AddComment("FDE address range");
1406 streamer.EmitAbsValue(Range, PCSize);
1409 // Augmentation Data Length
1410 unsigned augmentationLength = 0;
1413 augmentationLength += getSizeForEncoding(streamer, frame.LsdaEncoding);
1415 if (verboseAsm) streamer.AddComment("Augmentation size");
1416 streamer.EmitULEB128IntValue(augmentationLength);
1418 // Augmentation Data
1420 EmitSymbol(streamer, *frame.Lsda, frame.LsdaEncoding,
1421 "Language Specific Data Area");
1424 // Call Frame Instructions
1426 EmitCFIInstructions(streamer, frame.Instructions, frame.Begin);
1429 streamer.EmitValueToAlignment(PCSize);
1436 static const CIEKey getEmptyKey() { return CIEKey(0, 0, -1, false); }
1437 static const CIEKey getTombstoneKey() { return CIEKey(0, -1, 0, false); }
1439 CIEKey(const MCSymbol* Personality_, unsigned PersonalityEncoding_,
1440 unsigned LsdaEncoding_, bool IsSignalFrame_) :
1441 Personality(Personality_), PersonalityEncoding(PersonalityEncoding_),
1442 LsdaEncoding(LsdaEncoding_), IsSignalFrame(IsSignalFrame_) {
1444 const MCSymbol* Personality;
1445 unsigned PersonalityEncoding;
1446 unsigned LsdaEncoding;
1453 struct DenseMapInfo<CIEKey> {
1454 static CIEKey getEmptyKey() {
1455 return CIEKey::getEmptyKey();
1457 static CIEKey getTombstoneKey() {
1458 return CIEKey::getTombstoneKey();
1460 static unsigned getHashValue(const CIEKey &Key) {
1461 return static_cast<unsigned>(hash_combine(Key.Personality,
1462 Key.PersonalityEncoding,
1464 Key.IsSignalFrame));
1466 static bool isEqual(const CIEKey &LHS,
1467 const CIEKey &RHS) {
1468 return LHS.Personality == RHS.Personality &&
1469 LHS.PersonalityEncoding == RHS.PersonalityEncoding &&
1470 LHS.LsdaEncoding == RHS.LsdaEncoding &&
1471 LHS.IsSignalFrame == RHS.IsSignalFrame;
1476 void MCDwarfFrameEmitter::Emit(MCStreamer &Streamer,
1479 MCContext &Context = Streamer.getContext();
1480 MCObjectFileInfo *MOFI =
1481 const_cast<MCObjectFileInfo*>(Context.getObjectFileInfo());
1482 FrameEmitterImpl Emitter(UsingCFI, IsEH);
1483 ArrayRef<MCDwarfFrameInfo> FrameArray = Streamer.getFrameInfos();
1485 // Emit the compact unwind info if available.
1486 if (IsEH && MOFI->getCompactUnwindSection())
1487 for (unsigned i = 0, n = Streamer.getNumFrameInfos(); i < n; ++i) {
1488 const MCDwarfFrameInfo &Frame = Streamer.getFrameInfo(i);
1489 if (Frame.CompactUnwindEncoding)
1490 Emitter.EmitCompactUnwind(Streamer, Frame);
1493 const MCSection &Section = IsEH ? *MOFI->getEHFrameSection() :
1494 *MOFI->getDwarfFrameSection();
1495 Streamer.SwitchSection(&Section);
1496 MCSymbol *SectionStart = Context.CreateTempSymbol();
1497 Streamer.EmitLabel(SectionStart);
1498 Emitter.setSectionStart(SectionStart);
1500 MCSymbol *FDEEnd = NULL;
1501 DenseMap<CIEKey, const MCSymbol*> CIEStarts;
1503 const MCSymbol *DummyDebugKey = NULL;
1504 for (unsigned i = 0, n = FrameArray.size(); i < n; ++i) {
1505 const MCDwarfFrameInfo &Frame = FrameArray[i];
1506 CIEKey Key(Frame.Personality, Frame.PersonalityEncoding,
1507 Frame.LsdaEncoding, Frame.IsSignalFrame);
1508 const MCSymbol *&CIEStart = IsEH ? CIEStarts[Key] : DummyDebugKey;
1510 CIEStart = &Emitter.EmitCIE(Streamer, Frame.Personality,
1511 Frame.PersonalityEncoding, Frame.Lsda,
1512 Frame.IsSignalFrame,
1513 Frame.LsdaEncoding);
1515 FDEEnd = Emitter.EmitFDE(Streamer, *CIEStart, Frame);
1518 Streamer.EmitLabel(FDEEnd);
1521 Streamer.EmitValueToAlignment(Context.getAsmInfo().getPointerSize());
1523 Streamer.EmitLabel(FDEEnd);
1526 void MCDwarfFrameEmitter::EmitAdvanceLoc(MCStreamer &Streamer,
1527 uint64_t AddrDelta) {
1528 SmallString<256> Tmp;
1529 raw_svector_ostream OS(Tmp);
1530 MCDwarfFrameEmitter::EncodeAdvanceLoc(AddrDelta, OS);
1531 Streamer.EmitBytes(OS.str());
1534 void MCDwarfFrameEmitter::EncodeAdvanceLoc(uint64_t AddrDelta,
1536 // FIXME: Assumes the code alignment factor is 1.
1537 if (AddrDelta == 0) {
1538 } else if (isUIntN(6, AddrDelta)) {
1539 uint8_t Opcode = dwarf::DW_CFA_advance_loc | AddrDelta;
1541 } else if (isUInt<8>(AddrDelta)) {
1542 OS << uint8_t(dwarf::DW_CFA_advance_loc1);
1543 OS << uint8_t(AddrDelta);
1544 } else if (isUInt<16>(AddrDelta)) {
1545 // FIXME: check what is the correct behavior on a big endian machine.
1546 OS << uint8_t(dwarf::DW_CFA_advance_loc2);
1547 OS << uint8_t( AddrDelta & 0xff);
1548 OS << uint8_t((AddrDelta >> 8) & 0xff);
1550 // FIXME: check what is the correct behavior on a big endian machine.
1551 assert(isUInt<32>(AddrDelta));
1552 OS << uint8_t(dwarf::DW_CFA_advance_loc4);
1553 OS << uint8_t( AddrDelta & 0xff);
1554 OS << uint8_t((AddrDelta >> 8) & 0xff);
1555 OS << uint8_t((AddrDelta >> 16) & 0xff);
1556 OS << uint8_t((AddrDelta >> 24) & 0xff);