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/MCRegisterInfo.h"
20 #include "llvm/MC/MCStreamer.h"
21 #include "llvm/MC/MCSymbol.h"
22 #include "llvm/Support/Debug.h"
23 #include "llvm/Support/ErrorHandling.h"
24 #include "llvm/Support/LEB128.h"
25 #include "llvm/Support/Path.h"
26 #include "llvm/Support/SourceMgr.h"
27 #include "llvm/Support/raw_ostream.h"
30 // Given a special op, return the address skip amount (in units of
31 // DWARF2_LINE_MIN_INSN_LENGTH.
32 #define SPECIAL_ADDR(op) (((op) - DWARF2_LINE_OPCODE_BASE)/DWARF2_LINE_RANGE)
34 // The maximum address skip amount that can be encoded with a special op.
35 #define MAX_SPECIAL_ADDR_DELTA SPECIAL_ADDR(255)
37 // First special line opcode - leave room for the standard opcodes.
38 // Note: If you want to change this, you'll have to update the
39 // "standard_opcode_lengths" table that is emitted in DwarfFileTable::Emit().
40 #define DWARF2_LINE_OPCODE_BASE 13
42 // Minimum line offset in a special line info. opcode. This value
43 // was chosen to give a reasonable range of values.
44 #define DWARF2_LINE_BASE -5
46 // Range of line offsets in a special line info. opcode.
47 #define DWARF2_LINE_RANGE 14
49 static inline uint64_t ScaleAddrDelta(MCContext &Context, uint64_t AddrDelta) {
50 unsigned MinInsnLength = Context.getAsmInfo()->getMinInstAlignment();
51 if (MinInsnLength == 1)
53 if (AddrDelta % MinInsnLength != 0) {
54 // TODO: report this error, but really only once.
57 return AddrDelta / MinInsnLength;
61 // This is called when an instruction is assembled into the specified section
62 // and if there is information from the last .loc directive that has yet to have
63 // a line entry made for it is made.
65 void MCLineEntry::Make(MCStreamer *MCOS, const MCSection *Section) {
66 if (!MCOS->getContext().getDwarfLocSeen())
69 // Create a symbol at in the current section for use in the line entry.
70 MCSymbol *LineSym = MCOS->getContext().CreateTempSymbol();
71 // Set the value of the symbol to use for the MCLineEntry.
72 MCOS->EmitLabel(LineSym);
74 // Get the current .loc info saved in the context.
75 const MCDwarfLoc &DwarfLoc = MCOS->getContext().getCurrentDwarfLoc();
77 // Create a (local) line entry with the symbol and the current .loc info.
78 MCLineEntry LineEntry(LineSym, DwarfLoc);
80 // clear DwarfLocSeen saying the current .loc info is now used.
81 MCOS->getContext().ClearDwarfLocSeen();
83 // Get the MCLineSection for this section, if one does not exist for this
85 const DenseMap<const MCSection *, MCLineSection *> &MCLineSections =
86 MCOS->getContext().getMCLineSections();
87 MCLineSection *LineSection = MCLineSections.lookup(Section);
89 // Create a new MCLineSection. This will be deleted after the dwarf line
90 // table is created using it by iterating through the MCLineSections
92 LineSection = new MCLineSection;
93 // Save a pointer to the new LineSection into the MCLineSections DenseMap.
94 MCOS->getContext().addMCLineSection(Section, LineSection);
97 // Add the line entry to this section's entries.
98 LineSection->addLineEntry(LineEntry,
99 MCOS->getContext().getDwarfCompileUnitID());
103 // This helper routine returns an expression of End - Start + IntVal .
105 static inline const MCExpr *MakeStartMinusEndExpr(const MCStreamer &MCOS,
106 const MCSymbol &Start,
109 MCSymbolRefExpr::VariantKind Variant = MCSymbolRefExpr::VK_None;
111 MCSymbolRefExpr::Create(&End, Variant, MCOS.getContext());
113 MCSymbolRefExpr::Create(&Start, Variant, MCOS.getContext());
115 MCBinaryExpr::Create(MCBinaryExpr::Sub, Res, RHS, MCOS.getContext());
117 MCConstantExpr::Create(IntVal, MCOS.getContext());
119 MCBinaryExpr::Create(MCBinaryExpr::Sub, Res1, Res2, MCOS.getContext());
124 // This emits the Dwarf line table for the specified section from the entries
125 // in the LineSection.
127 static inline void EmitDwarfLineTable(MCStreamer *MCOS,
128 const MCSection *Section,
129 const MCLineSection *LineSection,
131 // This LineSection does not contain any LineEntry for the given Compile Unit.
132 if (!LineSection->containEntriesForID(CUID))
135 unsigned FileNum = 1;
136 unsigned LastLine = 1;
138 unsigned Flags = DWARF2_LINE_DEFAULT_IS_STMT ? DWARF2_FLAG_IS_STMT : 0;
140 MCSymbol *LastLabel = NULL;
142 // Loop through each MCLineEntry and encode the dwarf line number table.
143 for (MCLineSection::const_iterator
144 it = LineSection->getMCLineEntries(CUID).begin(),
145 ie = LineSection->getMCLineEntries(CUID).end(); it != ie; ++it) {
147 if (FileNum != it->getFileNum()) {
148 FileNum = it->getFileNum();
149 MCOS->EmitIntValue(dwarf::DW_LNS_set_file, 1);
150 MCOS->EmitULEB128IntValue(FileNum);
152 if (Column != it->getColumn()) {
153 Column = it->getColumn();
154 MCOS->EmitIntValue(dwarf::DW_LNS_set_column, 1);
155 MCOS->EmitULEB128IntValue(Column);
157 if (Isa != it->getIsa()) {
159 MCOS->EmitIntValue(dwarf::DW_LNS_set_isa, 1);
160 MCOS->EmitULEB128IntValue(Isa);
162 if ((it->getFlags() ^ Flags) & DWARF2_FLAG_IS_STMT) {
163 Flags = it->getFlags();
164 MCOS->EmitIntValue(dwarf::DW_LNS_negate_stmt, 1);
166 if (it->getFlags() & DWARF2_FLAG_BASIC_BLOCK)
167 MCOS->EmitIntValue(dwarf::DW_LNS_set_basic_block, 1);
168 if (it->getFlags() & DWARF2_FLAG_PROLOGUE_END)
169 MCOS->EmitIntValue(dwarf::DW_LNS_set_prologue_end, 1);
170 if (it->getFlags() & DWARF2_FLAG_EPILOGUE_BEGIN)
171 MCOS->EmitIntValue(dwarf::DW_LNS_set_epilogue_begin, 1);
173 int64_t LineDelta = static_cast<int64_t>(it->getLine()) - LastLine;
174 MCSymbol *Label = it->getLabel();
176 // At this point we want to emit/create the sequence to encode the delta in
177 // line numbers and the increment of the address from the previous Label
178 // and the current Label.
179 const MCAsmInfo *asmInfo = MCOS->getContext().getAsmInfo();
180 MCOS->EmitDwarfAdvanceLineAddr(LineDelta, LastLabel, Label,
181 asmInfo->getPointerSize());
183 LastLine = it->getLine();
187 // Emit a DW_LNE_end_sequence for the end of the section.
188 // Using the pointer Section create a temporary label at the end of the
189 // section and use that and the LastLabel to compute the address delta
190 // and use INT64_MAX as the line delta which is the signal that this is
191 // actually a DW_LNE_end_sequence.
193 // Switch to the section to be able to create a symbol at its end.
194 // TODO: keep track of the last subsection so that this symbol appears in the
196 MCOS->SwitchSection(Section);
198 MCContext &context = MCOS->getContext();
199 // Create a symbol at the end of the section.
200 MCSymbol *SectionEnd = context.CreateTempSymbol();
201 // Set the value of the symbol, as we are at the end of the section.
202 MCOS->EmitLabel(SectionEnd);
204 // Switch back the dwarf line section.
205 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfLineSection());
207 const MCAsmInfo *asmInfo = MCOS->getContext().getAsmInfo();
208 MCOS->EmitDwarfAdvanceLineAddr(INT64_MAX, LastLabel, SectionEnd,
209 asmInfo->getPointerSize());
213 // This emits the Dwarf file and the line tables.
215 const MCSymbol *MCDwarfFileTable::Emit(MCStreamer *MCOS) {
216 MCContext &context = MCOS->getContext();
217 // Switch to the section where the table will be emitted into.
218 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfLineSection());
220 const DenseMap<unsigned, MCSymbol *> &MCLineTableSymbols =
221 MCOS->getContext().getMCLineTableSymbols();
222 // CUID and MCLineTableSymbols are set in DwarfDebug, when DwarfDebug does
223 // not exist, CUID will be 0 and MCLineTableSymbols will be empty.
224 // Handle Compile Unit 0, the line table start symbol is the section symbol.
225 const MCSymbol *LineStartSym = EmitCU(MCOS, 0);
226 // Handle the rest of the Compile Units.
227 for (unsigned Is = 1, Ie = MCLineTableSymbols.size(); Is < Ie; Is++)
230 // Now delete the MCLineSections that were created in MCLineEntry::Make()
231 // and used to emit the line table.
232 const DenseMap<const MCSection *, MCLineSection *> &MCLineSections =
233 MCOS->getContext().getMCLineSections();
234 for (DenseMap<const MCSection *, MCLineSection *>::const_iterator it =
235 MCLineSections.begin(), ie = MCLineSections.end(); it != ie;
242 const MCSymbol *MCDwarfFileTable::EmitCU(MCStreamer *MCOS, unsigned CUID) {
243 MCContext &context = MCOS->getContext();
245 // Create a symbol at the beginning of the line table.
246 MCSymbol *LineStartSym = MCOS->getContext().getMCLineTableSymbol(CUID);
248 LineStartSym = context.CreateTempSymbol();
249 // Set the value of the symbol, as we are at the start of the line table.
250 MCOS->EmitLabel(LineStartSym);
252 // Create a symbol for the end of the section (to be set when we get there).
253 MCSymbol *LineEndSym = context.CreateTempSymbol();
255 // The first 4 bytes is the total length of the information for this
256 // compilation unit (not including these 4 bytes for the length).
257 MCOS->EmitAbsValue(MakeStartMinusEndExpr(*MCOS, *LineStartSym, *LineEndSym,4),
260 // Next 2 bytes is the Version, which is Dwarf 2.
261 MCOS->EmitIntValue(2, 2);
263 // Create a symbol for the end of the prologue (to be set when we get there).
264 MCSymbol *ProEndSym = context.CreateTempSymbol(); // Lprologue_end
266 // Length of the prologue, is the next 4 bytes. Which is the start of the
267 // section to the end of the prologue. Not including the 4 bytes for the
268 // total length, the 2 bytes for the version, and these 4 bytes for the
269 // length of the prologue.
270 MCOS->EmitAbsValue(MakeStartMinusEndExpr(*MCOS, *LineStartSym, *ProEndSym,
273 // Parameters of the state machine, are next.
274 MCOS->EmitIntValue(context.getAsmInfo()->getMinInstAlignment(), 1);
275 MCOS->EmitIntValue(DWARF2_LINE_DEFAULT_IS_STMT, 1);
276 MCOS->EmitIntValue(DWARF2_LINE_BASE, 1);
277 MCOS->EmitIntValue(DWARF2_LINE_RANGE, 1);
278 MCOS->EmitIntValue(DWARF2_LINE_OPCODE_BASE, 1);
280 // Standard opcode lengths
281 MCOS->EmitIntValue(0, 1); // length of DW_LNS_copy
282 MCOS->EmitIntValue(1, 1); // length of DW_LNS_advance_pc
283 MCOS->EmitIntValue(1, 1); // length of DW_LNS_advance_line
284 MCOS->EmitIntValue(1, 1); // length of DW_LNS_set_file
285 MCOS->EmitIntValue(1, 1); // length of DW_LNS_set_column
286 MCOS->EmitIntValue(0, 1); // length of DW_LNS_negate_stmt
287 MCOS->EmitIntValue(0, 1); // length of DW_LNS_set_basic_block
288 MCOS->EmitIntValue(0, 1); // length of DW_LNS_const_add_pc
289 MCOS->EmitIntValue(1, 1); // length of DW_LNS_fixed_advance_pc
290 MCOS->EmitIntValue(0, 1); // length of DW_LNS_set_prologue_end
291 MCOS->EmitIntValue(0, 1); // length of DW_LNS_set_epilogue_begin
292 MCOS->EmitIntValue(1, 1); // DW_LNS_set_isa
294 // Put out the directory and file tables.
296 // First the directory table.
297 const SmallVectorImpl<StringRef> &MCDwarfDirs =
298 context.getMCDwarfDirs(CUID);
299 for (unsigned i = 0; i < MCDwarfDirs.size(); i++) {
300 MCOS->EmitBytes(MCDwarfDirs[i]); // the DirectoryName
301 MCOS->EmitBytes(StringRef("\0", 1)); // the null term. of the string
303 MCOS->EmitIntValue(0, 1); // Terminate the directory list
305 // Second the file table.
306 const SmallVectorImpl<MCDwarfFile *> &MCDwarfFiles =
307 MCOS->getContext().getMCDwarfFiles(CUID);
308 for (unsigned i = 1; i < MCDwarfFiles.size(); i++) {
309 MCOS->EmitBytes(MCDwarfFiles[i]->getName()); // FileName
310 MCOS->EmitBytes(StringRef("\0", 1)); // the null term. of the string
312 MCOS->EmitULEB128IntValue(MCDwarfFiles[i]->getDirIndex());
313 MCOS->EmitIntValue(0, 1); // last modification timestamp (always 0)
314 MCOS->EmitIntValue(0, 1); // filesize (always 0)
316 MCOS->EmitIntValue(0, 1); // Terminate the file list
318 // This is the end of the prologue, so set the value of the symbol at the
319 // end of the prologue (that was used in a previous expression).
320 MCOS->EmitLabel(ProEndSym);
322 // Put out the line tables.
323 const DenseMap<const MCSection *, MCLineSection *> &MCLineSections =
324 MCOS->getContext().getMCLineSections();
325 const std::vector<const MCSection *> &MCLineSectionOrder =
326 MCOS->getContext().getMCLineSectionOrder();
327 for (std::vector<const MCSection*>::const_iterator it =
328 MCLineSectionOrder.begin(), ie = MCLineSectionOrder.end(); it != ie;
330 const MCSection *Sec = *it;
331 const MCLineSection *Line = MCLineSections.lookup(Sec);
332 EmitDwarfLineTable(MCOS, Sec, Line, CUID);
335 if (MCOS->getContext().getAsmInfo()->getLinkerRequiresNonEmptyDwarfLines()
336 && MCLineSectionOrder.begin() == MCLineSectionOrder.end()) {
337 // The darwin9 linker has a bug (see PR8715). For for 32-bit architectures
339 // total_length >= prologue_length + 10
340 // We are 4 bytes short, since we have total_length = 51 and
341 // prologue_length = 45
343 // The regular end_sequence should be sufficient.
344 MCDwarfLineAddr::Emit(MCOS, INT64_MAX, 0);
347 // This is the end of the section, so set the value of the symbol at the end
348 // of this section (that was used in a previous expression).
349 MCOS->EmitLabel(LineEndSym);
354 /// Utility function to emit the encoding to a streamer.
355 void MCDwarfLineAddr::Emit(MCStreamer *MCOS, int64_t LineDelta,
356 uint64_t AddrDelta) {
357 MCContext &Context = MCOS->getContext();
358 SmallString<256> Tmp;
359 raw_svector_ostream OS(Tmp);
360 MCDwarfLineAddr::Encode(Context, LineDelta, AddrDelta, OS);
361 MCOS->EmitBytes(OS.str());
364 /// Utility function to encode a Dwarf pair of LineDelta and AddrDeltas.
365 void MCDwarfLineAddr::Encode(MCContext &Context, int64_t LineDelta,
366 uint64_t AddrDelta, raw_ostream &OS) {
367 uint64_t Temp, Opcode;
368 bool NeedCopy = false;
370 // Scale the address delta by the minimum instruction length.
371 AddrDelta = ScaleAddrDelta(Context, AddrDelta);
373 // A LineDelta of INT64_MAX is a signal that this is actually a
374 // DW_LNE_end_sequence. We cannot use special opcodes here, since we want the
375 // end_sequence to emit the matrix entry.
376 if (LineDelta == INT64_MAX) {
377 if (AddrDelta == MAX_SPECIAL_ADDR_DELTA)
378 OS << char(dwarf::DW_LNS_const_add_pc);
380 OS << char(dwarf::DW_LNS_advance_pc);
381 encodeULEB128(AddrDelta, OS);
383 OS << char(dwarf::DW_LNS_extended_op);
385 OS << char(dwarf::DW_LNE_end_sequence);
389 // Bias the line delta by the base.
390 Temp = LineDelta - DWARF2_LINE_BASE;
392 // If the line increment is out of range of a special opcode, we must encode
393 // it with DW_LNS_advance_line.
394 if (Temp >= DWARF2_LINE_RANGE) {
395 OS << char(dwarf::DW_LNS_advance_line);
396 encodeSLEB128(LineDelta, OS);
399 Temp = 0 - DWARF2_LINE_BASE;
403 // Use DW_LNS_copy instead of a "line +0, addr +0" special opcode.
404 if (LineDelta == 0 && AddrDelta == 0) {
405 OS << char(dwarf::DW_LNS_copy);
409 // Bias the opcode by the special opcode base.
410 Temp += DWARF2_LINE_OPCODE_BASE;
412 // Avoid overflow when addr_delta is large.
413 if (AddrDelta < 256 + MAX_SPECIAL_ADDR_DELTA) {
414 // Try using a special opcode.
415 Opcode = Temp + AddrDelta * DWARF2_LINE_RANGE;
421 // Try using DW_LNS_const_add_pc followed by special op.
422 Opcode = Temp + (AddrDelta - MAX_SPECIAL_ADDR_DELTA) * DWARF2_LINE_RANGE;
424 OS << char(dwarf::DW_LNS_const_add_pc);
430 // Otherwise use DW_LNS_advance_pc.
431 OS << char(dwarf::DW_LNS_advance_pc);
432 encodeULEB128(AddrDelta, OS);
435 OS << char(dwarf::DW_LNS_copy);
440 void MCDwarfFile::print(raw_ostream &OS) const {
441 OS << '"' << getName() << '"';
444 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
445 void MCDwarfFile::dump() const {
450 // Utility function to write a tuple for .debug_abbrev.
451 static void EmitAbbrev(MCStreamer *MCOS, uint64_t Name, uint64_t Form) {
452 MCOS->EmitULEB128IntValue(Name);
453 MCOS->EmitULEB128IntValue(Form);
456 // When generating dwarf for assembly source files this emits
457 // the data for .debug_abbrev section which contains three DIEs.
458 static void EmitGenDwarfAbbrev(MCStreamer *MCOS) {
459 MCContext &context = MCOS->getContext();
460 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfAbbrevSection());
462 // DW_TAG_compile_unit DIE abbrev (1).
463 MCOS->EmitULEB128IntValue(1);
464 MCOS->EmitULEB128IntValue(dwarf::DW_TAG_compile_unit);
465 MCOS->EmitIntValue(dwarf::DW_CHILDREN_yes, 1);
466 EmitAbbrev(MCOS, dwarf::DW_AT_stmt_list, dwarf::DW_FORM_data4);
467 EmitAbbrev(MCOS, dwarf::DW_AT_low_pc, dwarf::DW_FORM_addr);
468 EmitAbbrev(MCOS, dwarf::DW_AT_high_pc, dwarf::DW_FORM_addr);
469 EmitAbbrev(MCOS, dwarf::DW_AT_name, dwarf::DW_FORM_string);
470 if (!context.getCompilationDir().empty())
471 EmitAbbrev(MCOS, dwarf::DW_AT_comp_dir, dwarf::DW_FORM_string);
472 StringRef DwarfDebugFlags = context.getDwarfDebugFlags();
473 if (!DwarfDebugFlags.empty())
474 EmitAbbrev(MCOS, dwarf::DW_AT_APPLE_flags, dwarf::DW_FORM_string);
475 EmitAbbrev(MCOS, dwarf::DW_AT_producer, dwarf::DW_FORM_string);
476 EmitAbbrev(MCOS, dwarf::DW_AT_language, dwarf::DW_FORM_data2);
477 EmitAbbrev(MCOS, 0, 0);
479 // DW_TAG_label DIE abbrev (2).
480 MCOS->EmitULEB128IntValue(2);
481 MCOS->EmitULEB128IntValue(dwarf::DW_TAG_label);
482 MCOS->EmitIntValue(dwarf::DW_CHILDREN_yes, 1);
483 EmitAbbrev(MCOS, dwarf::DW_AT_name, dwarf::DW_FORM_string);
484 EmitAbbrev(MCOS, dwarf::DW_AT_decl_file, dwarf::DW_FORM_data4);
485 EmitAbbrev(MCOS, dwarf::DW_AT_decl_line, dwarf::DW_FORM_data4);
486 EmitAbbrev(MCOS, dwarf::DW_AT_low_pc, dwarf::DW_FORM_addr);
487 EmitAbbrev(MCOS, dwarf::DW_AT_prototyped, dwarf::DW_FORM_flag);
488 EmitAbbrev(MCOS, 0, 0);
490 // DW_TAG_unspecified_parameters DIE abbrev (3).
491 MCOS->EmitULEB128IntValue(3);
492 MCOS->EmitULEB128IntValue(dwarf::DW_TAG_unspecified_parameters);
493 MCOS->EmitIntValue(dwarf::DW_CHILDREN_no, 1);
494 EmitAbbrev(MCOS, 0, 0);
496 // Terminate the abbreviations for this compilation unit.
497 MCOS->EmitIntValue(0, 1);
500 // When generating dwarf for assembly source files this emits the data for
501 // .debug_aranges section. Which contains a header and a table of pairs of
502 // PointerSize'ed values for the address and size of section(s) with line table
503 // entries (just the default .text in our case) and a terminating pair of zeros.
504 static void EmitGenDwarfAranges(MCStreamer *MCOS,
505 const MCSymbol *InfoSectionSymbol) {
506 MCContext &context = MCOS->getContext();
508 // Create a symbol at the end of the section that we are creating the dwarf
509 // debugging info to use later in here as part of the expression to calculate
510 // the size of the section for the table.
511 MCOS->SwitchSection(context.getGenDwarfSection());
512 MCSymbol *SectionEndSym = context.CreateTempSymbol();
513 MCOS->EmitLabel(SectionEndSym);
514 context.setGenDwarfSectionEndSym(SectionEndSym);
516 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfARangesSection());
518 // This will be the length of the .debug_aranges section, first account for
519 // the size of each item in the header (see below where we emit these items).
520 int Length = 4 + 2 + 4 + 1 + 1;
522 // Figure the padding after the header before the table of address and size
523 // pairs who's values are PointerSize'ed.
524 const MCAsmInfo *asmInfo = context.getAsmInfo();
525 int AddrSize = asmInfo->getPointerSize();
526 int Pad = 2 * AddrSize - (Length & (2 * AddrSize - 1));
527 if (Pad == 2 * AddrSize)
531 // Add the size of the pair of PointerSize'ed values for the address and size
532 // of the one default .text section we have in the table.
533 Length += 2 * AddrSize;
534 // And the pair of terminating zeros.
535 Length += 2 * AddrSize;
538 // Emit the header for this section.
539 // The 4 byte length not including the 4 byte value for the length.
540 MCOS->EmitIntValue(Length - 4, 4);
541 // The 2 byte version, which is 2.
542 MCOS->EmitIntValue(2, 2);
543 // The 4 byte offset to the compile unit in the .debug_info from the start
544 // of the .debug_info.
545 if (InfoSectionSymbol)
546 MCOS->EmitSymbolValue(InfoSectionSymbol, 4);
548 MCOS->EmitIntValue(0, 4);
549 // The 1 byte size of an address.
550 MCOS->EmitIntValue(AddrSize, 1);
551 // The 1 byte size of a segment descriptor, we use a value of zero.
552 MCOS->EmitIntValue(0, 1);
553 // Align the header with the padding if needed, before we put out the table.
554 for(int i = 0; i < Pad; i++)
555 MCOS->EmitIntValue(0, 1);
557 // Now emit the table of pairs of PointerSize'ed values for the section(s)
558 // address and size, in our case just the one default .text section.
559 const MCExpr *Addr = MCSymbolRefExpr::Create(
560 context.getGenDwarfSectionStartSym(), MCSymbolRefExpr::VK_None, context);
561 const MCExpr *Size = MakeStartMinusEndExpr(*MCOS,
562 *context.getGenDwarfSectionStartSym(), *SectionEndSym, 0);
563 MCOS->EmitAbsValue(Addr, AddrSize);
564 MCOS->EmitAbsValue(Size, AddrSize);
566 // And finally the pair of terminating zeros.
567 MCOS->EmitIntValue(0, AddrSize);
568 MCOS->EmitIntValue(0, AddrSize);
571 // When generating dwarf for assembly source files this emits the data for
572 // .debug_info section which contains three parts. The header, the compile_unit
573 // DIE and a list of label DIEs.
574 static void EmitGenDwarfInfo(MCStreamer *MCOS,
575 const MCSymbol *AbbrevSectionSymbol,
576 const MCSymbol *LineSectionSymbol) {
577 MCContext &context = MCOS->getContext();
579 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfInfoSection());
581 // Create a symbol at the start and end of this section used in here for the
582 // expression to calculate the length in the header.
583 MCSymbol *InfoStart = context.CreateTempSymbol();
584 MCOS->EmitLabel(InfoStart);
585 MCSymbol *InfoEnd = context.CreateTempSymbol();
587 // First part: the header.
589 // The 4 byte total length of the information for this compilation unit, not
590 // including these 4 bytes.
591 const MCExpr *Length = MakeStartMinusEndExpr(*MCOS, *InfoStart, *InfoEnd, 4);
592 MCOS->EmitAbsValue(Length, 4);
594 // The 2 byte DWARF version, which is 2.
595 MCOS->EmitIntValue(2, 2);
597 // The 4 byte offset to the debug abbrevs from the start of the .debug_abbrev,
598 // it is at the start of that section so this is zero.
599 if (AbbrevSectionSymbol) {
600 MCOS->EmitSymbolValue(AbbrevSectionSymbol, 4);
602 MCOS->EmitIntValue(0, 4);
605 const MCAsmInfo *asmInfo = context.getAsmInfo();
606 int AddrSize = asmInfo->getPointerSize();
607 // The 1 byte size of an address.
608 MCOS->EmitIntValue(AddrSize, 1);
610 // Second part: the compile_unit DIE.
612 // The DW_TAG_compile_unit DIE abbrev (1).
613 MCOS->EmitULEB128IntValue(1);
615 // DW_AT_stmt_list, a 4 byte offset from the start of the .debug_line section,
616 // which is at the start of that section so this is zero.
617 if (LineSectionSymbol) {
618 MCOS->EmitSymbolValue(LineSectionSymbol, 4);
620 MCOS->EmitIntValue(0, 4);
623 // AT_low_pc, the first address of the default .text section.
624 const MCExpr *Start = MCSymbolRefExpr::Create(
625 context.getGenDwarfSectionStartSym(), MCSymbolRefExpr::VK_None, context);
626 MCOS->EmitAbsValue(Start, AddrSize);
628 // AT_high_pc, the last address of the default .text section.
629 const MCExpr *End = MCSymbolRefExpr::Create(
630 context.getGenDwarfSectionEndSym(), MCSymbolRefExpr::VK_None, context);
631 MCOS->EmitAbsValue(End, AddrSize);
633 // AT_name, the name of the source file. Reconstruct from the first directory
634 // and file table entries.
635 const SmallVectorImpl<StringRef> &MCDwarfDirs =
636 context.getMCDwarfDirs();
637 if (MCDwarfDirs.size() > 0) {
638 MCOS->EmitBytes(MCDwarfDirs[0]);
639 MCOS->EmitBytes("/");
641 const SmallVectorImpl<MCDwarfFile *> &MCDwarfFiles =
642 MCOS->getContext().getMCDwarfFiles();
643 MCOS->EmitBytes(MCDwarfFiles[1]->getName());
644 MCOS->EmitIntValue(0, 1); // NULL byte to terminate the string.
646 // AT_comp_dir, the working directory the assembly was done in.
647 if (!context.getCompilationDir().empty()) {
648 MCOS->EmitBytes(context.getCompilationDir());
649 MCOS->EmitIntValue(0, 1); // NULL byte to terminate the string.
652 // AT_APPLE_flags, the command line arguments of the assembler tool.
653 StringRef DwarfDebugFlags = context.getDwarfDebugFlags();
654 if (!DwarfDebugFlags.empty()){
655 MCOS->EmitBytes(DwarfDebugFlags);
656 MCOS->EmitIntValue(0, 1); // NULL byte to terminate the string.
659 // AT_producer, the version of the assembler tool.
660 StringRef DwarfDebugProducer = context.getDwarfDebugProducer();
661 if (!DwarfDebugProducer.empty()){
662 MCOS->EmitBytes(DwarfDebugProducer);
665 MCOS->EmitBytes(StringRef("llvm-mc (based on LLVM "));
666 MCOS->EmitBytes(StringRef(PACKAGE_VERSION));
667 MCOS->EmitBytes(StringRef(")"));
669 MCOS->EmitIntValue(0, 1); // NULL byte to terminate the string.
671 // AT_language, a 4 byte value. We use DW_LANG_Mips_Assembler as the dwarf2
672 // draft has no standard code for assembler.
673 MCOS->EmitIntValue(dwarf::DW_LANG_Mips_Assembler, 2);
675 // Third part: the list of label DIEs.
677 // Loop on saved info for dwarf labels and create the DIEs for them.
678 const std::vector<const MCGenDwarfLabelEntry *> &Entries =
679 MCOS->getContext().getMCGenDwarfLabelEntries();
680 for (std::vector<const MCGenDwarfLabelEntry *>::const_iterator it =
681 Entries.begin(), ie = Entries.end(); it != ie;
683 const MCGenDwarfLabelEntry *Entry = *it;
685 // The DW_TAG_label DIE abbrev (2).
686 MCOS->EmitULEB128IntValue(2);
688 // AT_name, of the label without any leading underbar.
689 MCOS->EmitBytes(Entry->getName());
690 MCOS->EmitIntValue(0, 1); // NULL byte to terminate the string.
692 // AT_decl_file, index into the file table.
693 MCOS->EmitIntValue(Entry->getFileNumber(), 4);
695 // AT_decl_line, source line number.
696 MCOS->EmitIntValue(Entry->getLineNumber(), 4);
698 // AT_low_pc, start address of the label.
699 const MCExpr *AT_low_pc = MCSymbolRefExpr::Create(Entry->getLabel(),
700 MCSymbolRefExpr::VK_None, context);
701 MCOS->EmitAbsValue(AT_low_pc, AddrSize);
703 // DW_AT_prototyped, a one byte flag value of 0 saying we have no prototype.
704 MCOS->EmitIntValue(0, 1);
706 // The DW_TAG_unspecified_parameters DIE abbrev (3).
707 MCOS->EmitULEB128IntValue(3);
709 // Add the NULL DIE terminating the DW_TAG_unspecified_parameters DIE's.
710 MCOS->EmitIntValue(0, 1);
712 // Deallocate the MCGenDwarfLabelEntry classes that saved away the info
713 // for the dwarf labels.
714 for (std::vector<const MCGenDwarfLabelEntry *>::const_iterator it =
715 Entries.begin(), ie = Entries.end(); it != ie;
717 const MCGenDwarfLabelEntry *Entry = *it;
721 // Add the NULL DIE terminating the Compile Unit DIE's.
722 MCOS->EmitIntValue(0, 1);
724 // Now set the value of the symbol at the end of the info section.
725 MCOS->EmitLabel(InfoEnd);
729 // When generating dwarf for assembly source files this emits the Dwarf
732 void MCGenDwarfInfo::Emit(MCStreamer *MCOS, const MCSymbol *LineSectionSymbol) {
733 // Create the dwarf sections in this order (.debug_line already created).
734 MCContext &context = MCOS->getContext();
735 const MCAsmInfo *AsmInfo = context.getAsmInfo();
736 bool CreateDwarfSectionSymbols =
737 AsmInfo->doesDwarfUseRelocationsAcrossSections();
738 if (!CreateDwarfSectionSymbols)
739 LineSectionSymbol = NULL;
740 MCSymbol *AbbrevSectionSymbol = NULL;
741 MCSymbol *InfoSectionSymbol = NULL;
742 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfInfoSection());
743 if (CreateDwarfSectionSymbols) {
744 InfoSectionSymbol = context.CreateTempSymbol();
745 MCOS->EmitLabel(InfoSectionSymbol);
747 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfAbbrevSection());
748 if (CreateDwarfSectionSymbols) {
749 AbbrevSectionSymbol = context.CreateTempSymbol();
750 MCOS->EmitLabel(AbbrevSectionSymbol);
752 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfARangesSection());
754 // If there are no line table entries then do not emit any section contents.
755 if (context.getMCLineSections().empty())
758 // Output the data for .debug_aranges section.
759 EmitGenDwarfAranges(MCOS, InfoSectionSymbol);
761 // Output the data for .debug_abbrev section.
762 EmitGenDwarfAbbrev(MCOS);
764 // Output the data for .debug_info section.
765 EmitGenDwarfInfo(MCOS, AbbrevSectionSymbol, LineSectionSymbol);
769 // When generating dwarf for assembly source files this is called when symbol
770 // for a label is created. If this symbol is not a temporary and is in the
771 // section that dwarf is being generated for, save the needed info to create
774 void MCGenDwarfLabelEntry::Make(MCSymbol *Symbol, MCStreamer *MCOS,
775 SourceMgr &SrcMgr, SMLoc &Loc) {
776 // We won't create dwarf labels for temporary symbols or symbols not in
778 if (Symbol->isTemporary())
780 MCContext &context = MCOS->getContext();
781 if (context.getGenDwarfSection() != MCOS->getCurrentSection().first)
784 // The dwarf label's name does not have the symbol name's leading
786 StringRef Name = Symbol->getName();
787 if (Name.startswith("_"))
788 Name = Name.substr(1, Name.size()-1);
790 // Get the dwarf file number to be used for the dwarf label.
791 unsigned FileNumber = context.getGenDwarfFileNumber();
793 // Finding the line number is the expensive part which is why we just don't
794 // pass it in as for some symbols we won't create a dwarf label.
795 int CurBuffer = SrcMgr.FindBufferContainingLoc(Loc);
796 unsigned LineNumber = SrcMgr.FindLineNumber(Loc, CurBuffer);
798 // We create a temporary symbol for use for the AT_high_pc and AT_low_pc
799 // values so that they don't have things like an ARM thumb bit from the
800 // original symbol. So when used they won't get a low bit set after
802 MCSymbol *Label = context.CreateTempSymbol();
803 MCOS->EmitLabel(Label);
805 // Create and entry for the info and add it to the other entries.
806 MCGenDwarfLabelEntry *Entry =
807 new MCGenDwarfLabelEntry(Name, FileNumber, LineNumber, Label);
808 MCOS->getContext().addMCGenDwarfLabelEntry(Entry);
811 static int getDataAlignmentFactor(MCStreamer &streamer) {
812 MCContext &context = streamer.getContext();
813 const MCAsmInfo *asmInfo = context.getAsmInfo();
814 int size = asmInfo->getCalleeSaveStackSlotSize();
815 if (asmInfo->isStackGrowthDirectionUp())
821 static unsigned getSizeForEncoding(MCStreamer &streamer,
822 unsigned symbolEncoding) {
823 MCContext &context = streamer.getContext();
824 unsigned format = symbolEncoding & 0x0f;
826 default: llvm_unreachable("Unknown Encoding");
827 case dwarf::DW_EH_PE_absptr:
828 case dwarf::DW_EH_PE_signed:
829 return context.getAsmInfo()->getPointerSize();
830 case dwarf::DW_EH_PE_udata2:
831 case dwarf::DW_EH_PE_sdata2:
833 case dwarf::DW_EH_PE_udata4:
834 case dwarf::DW_EH_PE_sdata4:
836 case dwarf::DW_EH_PE_udata8:
837 case dwarf::DW_EH_PE_sdata8:
842 static void EmitFDESymbol(MCStreamer &streamer, const MCSymbol &symbol,
843 unsigned symbolEncoding, bool isEH,
844 const char *comment = 0) {
845 MCContext &context = streamer.getContext();
846 const MCAsmInfo *asmInfo = context.getAsmInfo();
847 const MCExpr *v = asmInfo->getExprForFDESymbol(&symbol,
850 unsigned size = getSizeForEncoding(streamer, symbolEncoding);
851 if (streamer.isVerboseAsm() && comment) streamer.AddComment(comment);
852 if (asmInfo->doDwarfFDESymbolsUseAbsDiff() && isEH)
853 streamer.EmitAbsValue(v, size);
855 streamer.EmitValue(v, size);
858 static void EmitPersonality(MCStreamer &streamer, const MCSymbol &symbol,
859 unsigned symbolEncoding) {
860 MCContext &context = streamer.getContext();
861 const MCAsmInfo *asmInfo = context.getAsmInfo();
862 const MCExpr *v = asmInfo->getExprForPersonalitySymbol(&symbol,
865 unsigned size = getSizeForEncoding(streamer, symbolEncoding);
866 streamer.EmitValue(v, size);
870 class FrameEmitterImpl {
875 const MCSymbol *SectionStart;
877 FrameEmitterImpl(bool usingCFI, bool isEH)
878 : CFAOffset(0), CIENum(0), UsingCFI(usingCFI), IsEH(isEH),
881 void setSectionStart(const MCSymbol *Label) { SectionStart = Label; }
883 /// EmitCompactUnwind - Emit the unwind information in a compact way.
884 void EmitCompactUnwind(MCStreamer &streamer,
885 const MCDwarfFrameInfo &frame);
887 const MCSymbol &EmitCIE(MCStreamer &streamer,
888 const MCSymbol *personality,
889 unsigned personalityEncoding,
890 const MCSymbol *lsda,
892 unsigned lsdaEncoding);
893 MCSymbol *EmitFDE(MCStreamer &streamer,
894 const MCSymbol &cieStart,
895 const MCDwarfFrameInfo &frame);
896 void EmitCFIInstructions(MCStreamer &streamer,
897 ArrayRef<MCCFIInstruction> Instrs,
898 MCSymbol *BaseLabel);
899 void EmitCFIInstruction(MCStreamer &Streamer,
900 const MCCFIInstruction &Instr);
903 } // end anonymous namespace
905 static void EmitEncodingByte(MCStreamer &Streamer, unsigned Encoding,
907 if (Streamer.isVerboseAsm()) {
910 default: EncStr = "<unknown encoding>"; break;
911 case dwarf::DW_EH_PE_absptr: EncStr = "absptr"; break;
912 case dwarf::DW_EH_PE_omit: EncStr = "omit"; break;
913 case dwarf::DW_EH_PE_pcrel: EncStr = "pcrel"; break;
914 case dwarf::DW_EH_PE_udata4: EncStr = "udata4"; break;
915 case dwarf::DW_EH_PE_udata8: EncStr = "udata8"; break;
916 case dwarf::DW_EH_PE_sdata4: EncStr = "sdata4"; break;
917 case dwarf::DW_EH_PE_sdata8: EncStr = "sdata8"; break;
918 case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata4:
919 EncStr = "pcrel udata4";
921 case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4:
922 EncStr = "pcrel sdata4";
924 case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata8:
925 EncStr = "pcrel udata8";
927 case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata8:
928 EncStr = "screl sdata8";
930 case dwarf::DW_EH_PE_indirect |dwarf::DW_EH_PE_pcrel|dwarf::DW_EH_PE_udata4:
931 EncStr = "indirect pcrel udata4";
933 case dwarf::DW_EH_PE_indirect |dwarf::DW_EH_PE_pcrel|dwarf::DW_EH_PE_sdata4:
934 EncStr = "indirect pcrel sdata4";
936 case dwarf::DW_EH_PE_indirect |dwarf::DW_EH_PE_pcrel|dwarf::DW_EH_PE_udata8:
937 EncStr = "indirect pcrel udata8";
939 case dwarf::DW_EH_PE_indirect |dwarf::DW_EH_PE_pcrel|dwarf::DW_EH_PE_sdata8:
940 EncStr = "indirect pcrel sdata8";
944 Streamer.AddComment(Twine(Prefix) + " = " + EncStr);
947 Streamer.EmitIntValue(Encoding, 1);
950 void FrameEmitterImpl::EmitCFIInstruction(MCStreamer &Streamer,
951 const MCCFIInstruction &Instr) {
952 int dataAlignmentFactor = getDataAlignmentFactor(Streamer);
953 bool VerboseAsm = Streamer.isVerboseAsm();
955 switch (Instr.getOperation()) {
956 case MCCFIInstruction::OpRegister: {
957 unsigned Reg1 = Instr.getRegister();
958 unsigned Reg2 = Instr.getRegister2();
960 Streamer.AddComment("DW_CFA_register");
961 Streamer.AddComment(Twine("Reg1 ") + Twine(Reg1));
962 Streamer.AddComment(Twine("Reg2 ") + Twine(Reg2));
964 Streamer.EmitIntValue(dwarf::DW_CFA_register, 1);
965 Streamer.EmitULEB128IntValue(Reg1);
966 Streamer.EmitULEB128IntValue(Reg2);
969 case MCCFIInstruction::OpWindowSave: {
970 Streamer.EmitIntValue(dwarf::DW_CFA_GNU_window_save, 1);
973 case MCCFIInstruction::OpUndefined: {
974 unsigned Reg = Instr.getRegister();
976 Streamer.AddComment("DW_CFA_undefined");
977 Streamer.AddComment(Twine("Reg ") + Twine(Reg));
979 Streamer.EmitIntValue(dwarf::DW_CFA_undefined, 1);
980 Streamer.EmitULEB128IntValue(Reg);
983 case MCCFIInstruction::OpAdjustCfaOffset:
984 case MCCFIInstruction::OpDefCfaOffset: {
985 const bool IsRelative =
986 Instr.getOperation() == MCCFIInstruction::OpAdjustCfaOffset;
989 Streamer.AddComment("DW_CFA_def_cfa_offset");
990 Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa_offset, 1);
993 CFAOffset += Instr.getOffset();
995 CFAOffset = -Instr.getOffset();
998 Streamer.AddComment(Twine("Offset " + Twine(CFAOffset)));
999 Streamer.EmitULEB128IntValue(CFAOffset);
1003 case MCCFIInstruction::OpDefCfa: {
1005 Streamer.AddComment("DW_CFA_def_cfa");
1006 Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa, 1);
1009 Streamer.AddComment(Twine("Reg ") + Twine(Instr.getRegister()));
1010 Streamer.EmitULEB128IntValue(Instr.getRegister());
1012 CFAOffset = -Instr.getOffset();
1015 Streamer.AddComment(Twine("Offset " + Twine(CFAOffset)));
1016 Streamer.EmitULEB128IntValue(CFAOffset);
1021 case MCCFIInstruction::OpDefCfaRegister: {
1023 Streamer.AddComment("DW_CFA_def_cfa_register");
1024 Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa_register, 1);
1027 Streamer.AddComment(Twine("Reg ") + Twine(Instr.getRegister()));
1028 Streamer.EmitULEB128IntValue(Instr.getRegister());
1033 case MCCFIInstruction::OpOffset:
1034 case MCCFIInstruction::OpRelOffset: {
1035 const bool IsRelative =
1036 Instr.getOperation() == MCCFIInstruction::OpRelOffset;
1038 unsigned Reg = Instr.getRegister();
1039 int Offset = Instr.getOffset();
1041 Offset -= CFAOffset;
1042 Offset = Offset / dataAlignmentFactor;
1045 if (VerboseAsm) Streamer.AddComment("DW_CFA_offset_extended_sf");
1046 Streamer.EmitIntValue(dwarf::DW_CFA_offset_extended_sf, 1);
1047 if (VerboseAsm) Streamer.AddComment(Twine("Reg ") + Twine(Reg));
1048 Streamer.EmitULEB128IntValue(Reg);
1049 if (VerboseAsm) Streamer.AddComment(Twine("Offset ") + Twine(Offset));
1050 Streamer.EmitSLEB128IntValue(Offset);
1051 } else if (Reg < 64) {
1052 if (VerboseAsm) Streamer.AddComment(Twine("DW_CFA_offset + Reg(") +
1054 Streamer.EmitIntValue(dwarf::DW_CFA_offset + Reg, 1);
1055 if (VerboseAsm) Streamer.AddComment(Twine("Offset ") + Twine(Offset));
1056 Streamer.EmitULEB128IntValue(Offset);
1058 if (VerboseAsm) Streamer.AddComment("DW_CFA_offset_extended");
1059 Streamer.EmitIntValue(dwarf::DW_CFA_offset_extended, 1);
1060 if (VerboseAsm) Streamer.AddComment(Twine("Reg ") + Twine(Reg));
1061 Streamer.EmitULEB128IntValue(Reg);
1062 if (VerboseAsm) Streamer.AddComment(Twine("Offset ") + Twine(Offset));
1063 Streamer.EmitULEB128IntValue(Offset);
1067 case MCCFIInstruction::OpRememberState:
1068 if (VerboseAsm) Streamer.AddComment("DW_CFA_remember_state");
1069 Streamer.EmitIntValue(dwarf::DW_CFA_remember_state, 1);
1071 case MCCFIInstruction::OpRestoreState:
1072 if (VerboseAsm) Streamer.AddComment("DW_CFA_restore_state");
1073 Streamer.EmitIntValue(dwarf::DW_CFA_restore_state, 1);
1075 case MCCFIInstruction::OpSameValue: {
1076 unsigned Reg = Instr.getRegister();
1077 if (VerboseAsm) Streamer.AddComment("DW_CFA_same_value");
1078 Streamer.EmitIntValue(dwarf::DW_CFA_same_value, 1);
1079 if (VerboseAsm) Streamer.AddComment(Twine("Reg ") + Twine(Reg));
1080 Streamer.EmitULEB128IntValue(Reg);
1083 case MCCFIInstruction::OpRestore: {
1084 unsigned Reg = Instr.getRegister();
1086 Streamer.AddComment("DW_CFA_restore");
1087 Streamer.AddComment(Twine("Reg ") + Twine(Reg));
1089 Streamer.EmitIntValue(dwarf::DW_CFA_restore | Reg, 1);
1092 case MCCFIInstruction::OpEscape:
1093 if (VerboseAsm) Streamer.AddComment("Escape bytes");
1094 Streamer.EmitBytes(Instr.getValues());
1097 llvm_unreachable("Unhandled case in switch");
1100 /// EmitFrameMoves - Emit frame instructions to describe the layout of the
1102 void FrameEmitterImpl::EmitCFIInstructions(MCStreamer &streamer,
1103 ArrayRef<MCCFIInstruction> Instrs,
1104 MCSymbol *BaseLabel) {
1105 for (unsigned i = 0, N = Instrs.size(); i < N; ++i) {
1106 const MCCFIInstruction &Instr = Instrs[i];
1107 MCSymbol *Label = Instr.getLabel();
1108 // Throw out move if the label is invalid.
1109 if (Label && !Label->isDefined()) continue; // Not emitted, in dead code.
1111 // Advance row if new location.
1112 if (BaseLabel && Label) {
1113 MCSymbol *ThisSym = Label;
1114 if (ThisSym != BaseLabel) {
1115 if (streamer.isVerboseAsm()) streamer.AddComment("DW_CFA_advance_loc4");
1116 streamer.EmitDwarfAdvanceFrameAddr(BaseLabel, ThisSym);
1117 BaseLabel = ThisSym;
1121 EmitCFIInstruction(streamer, Instr);
1125 /// EmitCompactUnwind - Emit the unwind information in a compact way.
1126 void FrameEmitterImpl::EmitCompactUnwind(MCStreamer &Streamer,
1127 const MCDwarfFrameInfo &Frame) {
1128 MCContext &Context = Streamer.getContext();
1129 const MCObjectFileInfo *MOFI = Context.getObjectFileInfo();
1130 bool VerboseAsm = Streamer.isVerboseAsm();
1132 // range-start range-length compact-unwind-enc personality-func lsda
1133 // _foo LfooEnd-_foo 0x00000023 0 0
1134 // _bar LbarEnd-_bar 0x00000025 __gxx_personality except_tab1
1136 // .section __LD,__compact_unwind,regular,debug
1138 // # compact unwind for _foo
1140 // .set L1,LfooEnd-_foo
1146 // # compact unwind for _bar
1148 // .set L2,LbarEnd-_bar
1151 // .quad __gxx_personality
1152 // .quad except_tab1
1154 uint32_t Encoding = Frame.CompactUnwindEncoding;
1155 if (!Encoding) return;
1156 bool DwarfEHFrameOnly = (Encoding == MOFI->getCompactUnwindDwarfEHFrameOnly());
1158 // The encoding needs to know we have an LSDA.
1159 if (!DwarfEHFrameOnly && Frame.Lsda)
1160 Encoding |= 0x40000000;
1163 unsigned FDEEncoding = MOFI->getFDEEncoding(UsingCFI);
1164 unsigned Size = getSizeForEncoding(Streamer, FDEEncoding);
1165 if (VerboseAsm) Streamer.AddComment("Range Start");
1166 Streamer.EmitSymbolValue(Frame.Function, Size);
1169 const MCExpr *Range = MakeStartMinusEndExpr(Streamer, *Frame.Begin,
1171 if (VerboseAsm) Streamer.AddComment("Range Length");
1172 Streamer.EmitAbsValue(Range, 4);
1175 Size = getSizeForEncoding(Streamer, dwarf::DW_EH_PE_udata4);
1176 if (VerboseAsm) Streamer.AddComment("Compact Unwind Encoding: 0x" +
1177 Twine::utohexstr(Encoding));
1178 Streamer.EmitIntValue(Encoding, Size);
1180 // Personality Function
1181 Size = getSizeForEncoding(Streamer, dwarf::DW_EH_PE_absptr);
1182 if (VerboseAsm) Streamer.AddComment("Personality Function");
1183 if (!DwarfEHFrameOnly && Frame.Personality)
1184 Streamer.EmitSymbolValue(Frame.Personality, Size);
1186 Streamer.EmitIntValue(0, Size); // No personality fn
1189 Size = getSizeForEncoding(Streamer, Frame.LsdaEncoding);
1190 if (VerboseAsm) Streamer.AddComment("LSDA");
1191 if (!DwarfEHFrameOnly && Frame.Lsda)
1192 Streamer.EmitSymbolValue(Frame.Lsda, Size);
1194 Streamer.EmitIntValue(0, Size); // No LSDA
1197 const MCSymbol &FrameEmitterImpl::EmitCIE(MCStreamer &streamer,
1198 const MCSymbol *personality,
1199 unsigned personalityEncoding,
1200 const MCSymbol *lsda,
1202 unsigned lsdaEncoding) {
1203 MCContext &context = streamer.getContext();
1204 const MCRegisterInfo *MRI = context.getRegisterInfo();
1205 const MCObjectFileInfo *MOFI = context.getObjectFileInfo();
1206 bool verboseAsm = streamer.isVerboseAsm();
1208 MCSymbol *sectionStart;
1209 if (MOFI->isFunctionEHFrameSymbolPrivate() || !IsEH)
1210 sectionStart = context.CreateTempSymbol();
1212 sectionStart = context.GetOrCreateSymbol(Twine("EH_frame") + Twine(CIENum));
1214 streamer.EmitLabel(sectionStart);
1217 MCSymbol *sectionEnd = context.CreateTempSymbol();
1220 const MCExpr *Length = MakeStartMinusEndExpr(streamer, *sectionStart,
1222 if (verboseAsm) streamer.AddComment("CIE Length");
1223 streamer.EmitAbsValue(Length, 4);
1226 unsigned CIE_ID = IsEH ? 0 : -1;
1227 if (verboseAsm) streamer.AddComment("CIE ID Tag");
1228 streamer.EmitIntValue(CIE_ID, 4);
1231 if (verboseAsm) streamer.AddComment("DW_CIE_VERSION");
1232 streamer.EmitIntValue(dwarf::DW_CIE_VERSION, 1);
1234 // Augmentation String
1235 SmallString<8> Augmentation;
1237 if (verboseAsm) streamer.AddComment("CIE Augmentation");
1238 Augmentation += "z";
1240 Augmentation += "P";
1242 Augmentation += "L";
1243 Augmentation += "R";
1245 Augmentation += "S";
1246 streamer.EmitBytes(Augmentation.str());
1248 streamer.EmitIntValue(0, 1);
1250 // Code Alignment Factor
1251 if (verboseAsm) streamer.AddComment("CIE Code Alignment Factor");
1252 streamer.EmitULEB128IntValue(context.getAsmInfo()->getMinInstAlignment());
1254 // Data Alignment Factor
1255 if (verboseAsm) streamer.AddComment("CIE Data Alignment Factor");
1256 streamer.EmitSLEB128IntValue(getDataAlignmentFactor(streamer));
1258 // Return Address Register
1259 if (verboseAsm) streamer.AddComment("CIE Return Address Column");
1260 streamer.EmitULEB128IntValue(MRI->getDwarfRegNum(MRI->getRARegister(), true));
1262 // Augmentation Data Length (optional)
1264 unsigned augmentationLength = 0;
1267 // Personality Encoding
1268 augmentationLength += 1;
1270 augmentationLength += getSizeForEncoding(streamer, personalityEncoding);
1273 augmentationLength += 1;
1274 // Encoding of the FDE pointers
1275 augmentationLength += 1;
1277 if (verboseAsm) streamer.AddComment("Augmentation Size");
1278 streamer.EmitULEB128IntValue(augmentationLength);
1280 // Augmentation Data (optional)
1282 // Personality Encoding
1283 EmitEncodingByte(streamer, personalityEncoding,
1284 "Personality Encoding");
1286 if (verboseAsm) streamer.AddComment("Personality");
1287 EmitPersonality(streamer, *personality, personalityEncoding);
1291 EmitEncodingByte(streamer, lsdaEncoding, "LSDA Encoding");
1293 // Encoding of the FDE pointers
1294 EmitEncodingByte(streamer, MOFI->getFDEEncoding(UsingCFI),
1298 // Initial Instructions
1300 const MCAsmInfo *MAI = context.getAsmInfo();
1301 const std::vector<MCCFIInstruction> &Instructions =
1302 MAI->getInitialFrameState();
1303 EmitCFIInstructions(streamer, Instructions, NULL);
1306 streamer.EmitValueToAlignment(IsEH ? 4 : MAI->getPointerSize());
1308 streamer.EmitLabel(sectionEnd);
1309 return *sectionStart;
1312 MCSymbol *FrameEmitterImpl::EmitFDE(MCStreamer &streamer,
1313 const MCSymbol &cieStart,
1314 const MCDwarfFrameInfo &frame) {
1315 MCContext &context = streamer.getContext();
1316 MCSymbol *fdeStart = context.CreateTempSymbol();
1317 MCSymbol *fdeEnd = context.CreateTempSymbol();
1318 const MCObjectFileInfo *MOFI = context.getObjectFileInfo();
1319 bool verboseAsm = streamer.isVerboseAsm();
1321 if (IsEH && frame.Function && !MOFI->isFunctionEHFrameSymbolPrivate()) {
1323 context.GetOrCreateSymbol(frame.Function->getName() + Twine(".eh"));
1324 streamer.EmitEHSymAttributes(frame.Function, EHSym);
1325 streamer.EmitLabel(EHSym);
1329 const MCExpr *Length = MakeStartMinusEndExpr(streamer, *fdeStart, *fdeEnd, 0);
1330 if (verboseAsm) streamer.AddComment("FDE Length");
1331 streamer.EmitAbsValue(Length, 4);
1333 streamer.EmitLabel(fdeStart);
1336 const MCAsmInfo *asmInfo = context.getAsmInfo();
1338 const MCExpr *offset = MakeStartMinusEndExpr(streamer, cieStart, *fdeStart,
1340 if (verboseAsm) streamer.AddComment("FDE CIE Offset");
1341 streamer.EmitAbsValue(offset, 4);
1342 } else if (!asmInfo->doesDwarfUseRelocationsAcrossSections()) {
1343 const MCExpr *offset = MakeStartMinusEndExpr(streamer, *SectionStart,
1345 streamer.EmitAbsValue(offset, 4);
1347 streamer.EmitSymbolValue(&cieStart, 4);
1351 unsigned PCEncoding = IsEH ? MOFI->getFDEEncoding(UsingCFI)
1352 : (unsigned)dwarf::DW_EH_PE_absptr;
1353 unsigned PCSize = getSizeForEncoding(streamer, PCEncoding);
1354 EmitFDESymbol(streamer, *frame.Begin, PCEncoding, IsEH, "FDE initial location");
1357 const MCExpr *Range = MakeStartMinusEndExpr(streamer, *frame.Begin,
1359 if (verboseAsm) streamer.AddComment("FDE address range");
1360 streamer.EmitAbsValue(Range, PCSize);
1363 // Augmentation Data Length
1364 unsigned augmentationLength = 0;
1367 augmentationLength += getSizeForEncoding(streamer, frame.LsdaEncoding);
1369 if (verboseAsm) streamer.AddComment("Augmentation size");
1370 streamer.EmitULEB128IntValue(augmentationLength);
1372 // Augmentation Data
1374 EmitFDESymbol(streamer, *frame.Lsda, frame.LsdaEncoding, true,
1375 "Language Specific Data Area");
1378 // Call Frame Instructions
1379 EmitCFIInstructions(streamer, frame.Instructions, frame.Begin);
1382 streamer.EmitValueToAlignment(PCSize);
1389 static const CIEKey getEmptyKey() { return CIEKey(0, 0, -1, false); }
1390 static const CIEKey getTombstoneKey() { return CIEKey(0, -1, 0, false); }
1392 CIEKey(const MCSymbol* Personality_, unsigned PersonalityEncoding_,
1393 unsigned LsdaEncoding_, bool IsSignalFrame_) :
1394 Personality(Personality_), PersonalityEncoding(PersonalityEncoding_),
1395 LsdaEncoding(LsdaEncoding_), IsSignalFrame(IsSignalFrame_) {
1397 const MCSymbol* Personality;
1398 unsigned PersonalityEncoding;
1399 unsigned LsdaEncoding;
1406 struct DenseMapInfo<CIEKey> {
1407 static CIEKey getEmptyKey() {
1408 return CIEKey::getEmptyKey();
1410 static CIEKey getTombstoneKey() {
1411 return CIEKey::getTombstoneKey();
1413 static unsigned getHashValue(const CIEKey &Key) {
1414 return static_cast<unsigned>(hash_combine(Key.Personality,
1415 Key.PersonalityEncoding,
1417 Key.IsSignalFrame));
1419 static bool isEqual(const CIEKey &LHS,
1420 const CIEKey &RHS) {
1421 return LHS.Personality == RHS.Personality &&
1422 LHS.PersonalityEncoding == RHS.PersonalityEncoding &&
1423 LHS.LsdaEncoding == RHS.LsdaEncoding &&
1424 LHS.IsSignalFrame == RHS.IsSignalFrame;
1429 void MCDwarfFrameEmitter::Emit(MCStreamer &Streamer, MCAsmBackend *MAB,
1430 bool UsingCFI, bool IsEH) {
1431 Streamer.generateCompactUnwindEncodings(MAB);
1433 MCContext &Context = Streamer.getContext();
1434 const MCObjectFileInfo *MOFI = Context.getObjectFileInfo();
1435 FrameEmitterImpl Emitter(UsingCFI, IsEH);
1436 ArrayRef<MCDwarfFrameInfo> FrameArray = Streamer.getFrameInfos();
1438 // Emit the compact unwind info if available.
1439 if (IsEH && MOFI->getCompactUnwindSection()) {
1440 bool SectionEmitted = false;
1441 for (unsigned i = 0, n = FrameArray.size(); i < n; ++i) {
1442 const MCDwarfFrameInfo &Frame = FrameArray[i];
1443 if (Frame.CompactUnwindEncoding == 0) continue;
1444 if (!SectionEmitted) {
1445 Streamer.SwitchSection(MOFI->getCompactUnwindSection());
1446 Streamer.EmitValueToAlignment(Context.getAsmInfo()->getPointerSize());
1447 SectionEmitted = true;
1449 Emitter.EmitCompactUnwind(Streamer, Frame);
1453 const MCSection &Section =
1454 IsEH ? *const_cast<MCObjectFileInfo*>(MOFI)->getEHFrameSection() :
1455 *MOFI->getDwarfFrameSection();
1456 Streamer.SwitchSection(&Section);
1457 MCSymbol *SectionStart = Context.CreateTempSymbol();
1458 Streamer.EmitLabel(SectionStart);
1459 Emitter.setSectionStart(SectionStart);
1461 MCSymbol *FDEEnd = NULL;
1462 DenseMap<CIEKey, const MCSymbol*> CIEStarts;
1464 const MCSymbol *DummyDebugKey = NULL;
1465 for (unsigned i = 0, n = FrameArray.size(); i < n; ++i) {
1466 const MCDwarfFrameInfo &Frame = FrameArray[i];
1467 CIEKey Key(Frame.Personality, Frame.PersonalityEncoding,
1468 Frame.LsdaEncoding, Frame.IsSignalFrame);
1469 const MCSymbol *&CIEStart = IsEH ? CIEStarts[Key] : DummyDebugKey;
1471 CIEStart = &Emitter.EmitCIE(Streamer, Frame.Personality,
1472 Frame.PersonalityEncoding, Frame.Lsda,
1473 Frame.IsSignalFrame,
1474 Frame.LsdaEncoding);
1476 FDEEnd = Emitter.EmitFDE(Streamer, *CIEStart, Frame);
1479 Streamer.EmitLabel(FDEEnd);
1482 Streamer.EmitValueToAlignment(Context.getAsmInfo()->getPointerSize());
1484 Streamer.EmitLabel(FDEEnd);
1487 void MCDwarfFrameEmitter::EmitAdvanceLoc(MCStreamer &Streamer,
1488 uint64_t AddrDelta) {
1489 MCContext &Context = Streamer.getContext();
1490 SmallString<256> Tmp;
1491 raw_svector_ostream OS(Tmp);
1492 MCDwarfFrameEmitter::EncodeAdvanceLoc(Context, AddrDelta, OS);
1493 Streamer.EmitBytes(OS.str());
1496 void MCDwarfFrameEmitter::EncodeAdvanceLoc(MCContext &Context,
1499 // Scale the address delta by the minimum instruction length.
1500 AddrDelta = ScaleAddrDelta(Context, AddrDelta);
1502 if (AddrDelta == 0) {
1503 } else if (isUIntN(6, AddrDelta)) {
1504 uint8_t Opcode = dwarf::DW_CFA_advance_loc | AddrDelta;
1506 } else if (isUInt<8>(AddrDelta)) {
1507 OS << uint8_t(dwarf::DW_CFA_advance_loc1);
1508 OS << uint8_t(AddrDelta);
1509 } else if (isUInt<16>(AddrDelta)) {
1510 // FIXME: check what is the correct behavior on a big endian machine.
1511 OS << uint8_t(dwarf::DW_CFA_advance_loc2);
1512 OS << uint8_t( AddrDelta & 0xff);
1513 OS << uint8_t((AddrDelta >> 8) & 0xff);
1515 // FIXME: check what is the correct behavior on a big endian machine.
1516 assert(isUInt<32>(AddrDelta));
1517 OS << uint8_t(dwarf::DW_CFA_advance_loc4);
1518 OS << uint8_t( AddrDelta & 0xff);
1519 OS << uint8_t((AddrDelta >> 8) & 0xff);
1520 OS << uint8_t((AddrDelta >> 16) & 0xff);
1521 OS << uint8_t((AddrDelta >> 24) & 0xff);