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 EmitAbbrev(MCOS, dwarf::DW_AT_comp_dir, dwarf::DW_FORM_string);
471 StringRef DwarfDebugFlags = context.getDwarfDebugFlags();
472 if (!DwarfDebugFlags.empty())
473 EmitAbbrev(MCOS, dwarf::DW_AT_APPLE_flags, dwarf::DW_FORM_string);
474 EmitAbbrev(MCOS, dwarf::DW_AT_producer, dwarf::DW_FORM_string);
475 EmitAbbrev(MCOS, dwarf::DW_AT_language, dwarf::DW_FORM_data2);
476 EmitAbbrev(MCOS, 0, 0);
478 // DW_TAG_label DIE abbrev (2).
479 MCOS->EmitULEB128IntValue(2);
480 MCOS->EmitULEB128IntValue(dwarf::DW_TAG_label);
481 MCOS->EmitIntValue(dwarf::DW_CHILDREN_yes, 1);
482 EmitAbbrev(MCOS, dwarf::DW_AT_name, dwarf::DW_FORM_string);
483 EmitAbbrev(MCOS, dwarf::DW_AT_decl_file, dwarf::DW_FORM_data4);
484 EmitAbbrev(MCOS, dwarf::DW_AT_decl_line, dwarf::DW_FORM_data4);
485 EmitAbbrev(MCOS, dwarf::DW_AT_low_pc, dwarf::DW_FORM_addr);
486 EmitAbbrev(MCOS, dwarf::DW_AT_prototyped, dwarf::DW_FORM_flag);
487 EmitAbbrev(MCOS, 0, 0);
489 // DW_TAG_unspecified_parameters DIE abbrev (3).
490 MCOS->EmitULEB128IntValue(3);
491 MCOS->EmitULEB128IntValue(dwarf::DW_TAG_unspecified_parameters);
492 MCOS->EmitIntValue(dwarf::DW_CHILDREN_no, 1);
493 EmitAbbrev(MCOS, 0, 0);
495 // Terminate the abbreviations for this compilation unit.
496 MCOS->EmitIntValue(0, 1);
499 // When generating dwarf for assembly source files this emits the data for
500 // .debug_aranges section. Which contains a header and a table of pairs of
501 // PointerSize'ed values for the address and size of section(s) with line table
502 // entries (just the default .text in our case) and a terminating pair of zeros.
503 static void EmitGenDwarfAranges(MCStreamer *MCOS,
504 const MCSymbol *InfoSectionSymbol) {
505 MCContext &context = MCOS->getContext();
507 // Create a symbol at the end of the section that we are creating the dwarf
508 // debugging info to use later in here as part of the expression to calculate
509 // the size of the section for the table.
510 MCOS->SwitchSection(context.getGenDwarfSection());
511 MCSymbol *SectionEndSym = context.CreateTempSymbol();
512 MCOS->EmitLabel(SectionEndSym);
513 context.setGenDwarfSectionEndSym(SectionEndSym);
515 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfARangesSection());
517 // This will be the length of the .debug_aranges section, first account for
518 // the size of each item in the header (see below where we emit these items).
519 int Length = 4 + 2 + 4 + 1 + 1;
521 // Figure the padding after the header before the table of address and size
522 // pairs who's values are PointerSize'ed.
523 const MCAsmInfo &asmInfo = context.getAsmInfo();
524 int AddrSize = asmInfo.getPointerSize();
525 int Pad = 2 * AddrSize - (Length & (2 * AddrSize - 1));
526 if (Pad == 2 * AddrSize)
530 // Add the size of the pair of PointerSize'ed values for the address and size
531 // of the one default .text section we have in the table.
532 Length += 2 * AddrSize;
533 // And the pair of terminating zeros.
534 Length += 2 * AddrSize;
537 // Emit the header for this section.
538 // The 4 byte length not including the 4 byte value for the length.
539 MCOS->EmitIntValue(Length - 4, 4);
540 // The 2 byte version, which is 2.
541 MCOS->EmitIntValue(2, 2);
542 // The 4 byte offset to the compile unit in the .debug_info from the start
543 // of the .debug_info.
544 if (InfoSectionSymbol)
545 MCOS->EmitSymbolValue(InfoSectionSymbol, 4);
547 MCOS->EmitIntValue(0, 4);
548 // The 1 byte size of an address.
549 MCOS->EmitIntValue(AddrSize, 1);
550 // The 1 byte size of a segment descriptor, we use a value of zero.
551 MCOS->EmitIntValue(0, 1);
552 // Align the header with the padding if needed, before we put out the table.
553 for(int i = 0; i < Pad; i++)
554 MCOS->EmitIntValue(0, 1);
556 // Now emit the table of pairs of PointerSize'ed values for the section(s)
557 // address and size, in our case just the one default .text section.
558 const MCExpr *Addr = MCSymbolRefExpr::Create(
559 context.getGenDwarfSectionStartSym(), MCSymbolRefExpr::VK_None, context);
560 const MCExpr *Size = MakeStartMinusEndExpr(*MCOS,
561 *context.getGenDwarfSectionStartSym(), *SectionEndSym, 0);
562 MCOS->EmitAbsValue(Addr, AddrSize);
563 MCOS->EmitAbsValue(Size, AddrSize);
565 // And finally the pair of terminating zeros.
566 MCOS->EmitIntValue(0, AddrSize);
567 MCOS->EmitIntValue(0, AddrSize);
570 // When generating dwarf for assembly source files this emits the data for
571 // .debug_info section which contains three parts. The header, the compile_unit
572 // DIE and a list of label DIEs.
573 static void EmitGenDwarfInfo(MCStreamer *MCOS,
574 const MCSymbol *AbbrevSectionSymbol,
575 const MCSymbol *LineSectionSymbol) {
576 MCContext &context = MCOS->getContext();
578 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfInfoSection());
580 // Create a symbol at the start and end of this section used in here for the
581 // expression to calculate the length in the header.
582 MCSymbol *InfoStart = context.CreateTempSymbol();
583 MCOS->EmitLabel(InfoStart);
584 MCSymbol *InfoEnd = context.CreateTempSymbol();
586 // First part: the header.
588 // The 4 byte total length of the information for this compilation unit, not
589 // including these 4 bytes.
590 const MCExpr *Length = MakeStartMinusEndExpr(*MCOS, *InfoStart, *InfoEnd, 4);
591 MCOS->EmitAbsValue(Length, 4);
593 // The 2 byte DWARF version, which is 2.
594 MCOS->EmitIntValue(2, 2);
596 // The 4 byte offset to the debug abbrevs from the start of the .debug_abbrev,
597 // it is at the start of that section so this is zero.
598 if (AbbrevSectionSymbol) {
599 MCOS->EmitSymbolValue(AbbrevSectionSymbol, 4);
601 MCOS->EmitIntValue(0, 4);
604 const MCAsmInfo &asmInfo = context.getAsmInfo();
605 int AddrSize = asmInfo.getPointerSize();
606 // The 1 byte size of an address.
607 MCOS->EmitIntValue(AddrSize, 1);
609 // Second part: the compile_unit DIE.
611 // The DW_TAG_compile_unit DIE abbrev (1).
612 MCOS->EmitULEB128IntValue(1);
614 // DW_AT_stmt_list, a 4 byte offset from the start of the .debug_line section,
615 // which is at the start of that section so this is zero.
616 if (LineSectionSymbol) {
617 MCOS->EmitSymbolValue(LineSectionSymbol, 4);
619 MCOS->EmitIntValue(0, 4);
622 // AT_low_pc, the first address of the default .text section.
623 const MCExpr *Start = MCSymbolRefExpr::Create(
624 context.getGenDwarfSectionStartSym(), MCSymbolRefExpr::VK_None, context);
625 MCOS->EmitAbsValue(Start, AddrSize);
627 // AT_high_pc, the last address of the default .text section.
628 const MCExpr *End = MCSymbolRefExpr::Create(
629 context.getGenDwarfSectionEndSym(), MCSymbolRefExpr::VK_None, context);
630 MCOS->EmitAbsValue(End, AddrSize);
632 // AT_name, the name of the source file. Reconstruct from the first directory
633 // and file table entries.
634 const SmallVectorImpl<StringRef> &MCDwarfDirs =
635 context.getMCDwarfDirs();
636 if (MCDwarfDirs.size() > 0) {
637 MCOS->EmitBytes(MCDwarfDirs[0]);
638 MCOS->EmitBytes("/");
640 const SmallVectorImpl<MCDwarfFile *> &MCDwarfFiles =
641 MCOS->getContext().getMCDwarfFiles();
642 MCOS->EmitBytes(MCDwarfFiles[1]->getName());
643 MCOS->EmitIntValue(0, 1); // NULL byte to terminate the string.
645 // AT_comp_dir, the working directory the assembly was done in.
646 MCOS->EmitBytes(context.getCompilationDir());
647 MCOS->EmitIntValue(0, 1); // NULL byte to terminate the string.
649 // AT_APPLE_flags, the command line arguments of the assembler tool.
650 StringRef DwarfDebugFlags = context.getDwarfDebugFlags();
651 if (!DwarfDebugFlags.empty()){
652 MCOS->EmitBytes(DwarfDebugFlags);
653 MCOS->EmitIntValue(0, 1); // NULL byte to terminate the string.
656 // AT_producer, the version of the assembler tool.
657 StringRef DwarfDebugProducer = context.getDwarfDebugProducer();
658 if (!DwarfDebugProducer.empty()){
659 MCOS->EmitBytes(DwarfDebugProducer);
662 MCOS->EmitBytes(StringRef("llvm-mc (based on LLVM "));
663 MCOS->EmitBytes(StringRef(PACKAGE_VERSION));
664 MCOS->EmitBytes(StringRef(")"));
666 MCOS->EmitIntValue(0, 1); // NULL byte to terminate the string.
668 // AT_language, a 4 byte value. We use DW_LANG_Mips_Assembler as the dwarf2
669 // draft has no standard code for assembler.
670 MCOS->EmitIntValue(dwarf::DW_LANG_Mips_Assembler, 2);
672 // Third part: the list of label DIEs.
674 // Loop on saved info for dwarf labels and create the DIEs for them.
675 const std::vector<const MCGenDwarfLabelEntry *> &Entries =
676 MCOS->getContext().getMCGenDwarfLabelEntries();
677 for (std::vector<const MCGenDwarfLabelEntry *>::const_iterator it =
678 Entries.begin(), ie = Entries.end(); it != ie;
680 const MCGenDwarfLabelEntry *Entry = *it;
682 // The DW_TAG_label DIE abbrev (2).
683 MCOS->EmitULEB128IntValue(2);
685 // AT_name, of the label without any leading underbar.
686 MCOS->EmitBytes(Entry->getName());
687 MCOS->EmitIntValue(0, 1); // NULL byte to terminate the string.
689 // AT_decl_file, index into the file table.
690 MCOS->EmitIntValue(Entry->getFileNumber(), 4);
692 // AT_decl_line, source line number.
693 MCOS->EmitIntValue(Entry->getLineNumber(), 4);
695 // AT_low_pc, start address of the label.
696 const MCExpr *AT_low_pc = MCSymbolRefExpr::Create(Entry->getLabel(),
697 MCSymbolRefExpr::VK_None, context);
698 MCOS->EmitAbsValue(AT_low_pc, AddrSize);
700 // DW_AT_prototyped, a one byte flag value of 0 saying we have no prototype.
701 MCOS->EmitIntValue(0, 1);
703 // The DW_TAG_unspecified_parameters DIE abbrev (3).
704 MCOS->EmitULEB128IntValue(3);
706 // Add the NULL DIE terminating the DW_TAG_unspecified_parameters DIE's.
707 MCOS->EmitIntValue(0, 1);
709 // Deallocate the MCGenDwarfLabelEntry classes that saved away the info
710 // for the dwarf labels.
711 for (std::vector<const MCGenDwarfLabelEntry *>::const_iterator it =
712 Entries.begin(), ie = Entries.end(); it != ie;
714 const MCGenDwarfLabelEntry *Entry = *it;
718 // Add the NULL DIE terminating the Compile Unit DIE's.
719 MCOS->EmitIntValue(0, 1);
721 // Now set the value of the symbol at the end of the info section.
722 MCOS->EmitLabel(InfoEnd);
726 // When generating dwarf for assembly source files this emits the Dwarf
729 void MCGenDwarfInfo::Emit(MCStreamer *MCOS, const MCSymbol *LineSectionSymbol) {
730 // Create the dwarf sections in this order (.debug_line already created).
731 MCContext &context = MCOS->getContext();
732 const MCAsmInfo &AsmInfo = context.getAsmInfo();
733 bool CreateDwarfSectionSymbols =
734 AsmInfo.doesDwarfUseRelocationsAcrossSections();
735 if (!CreateDwarfSectionSymbols)
736 LineSectionSymbol = NULL;
737 MCSymbol *AbbrevSectionSymbol = NULL;
738 MCSymbol *InfoSectionSymbol = NULL;
739 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfInfoSection());
740 if (CreateDwarfSectionSymbols) {
741 InfoSectionSymbol = context.CreateTempSymbol();
742 MCOS->EmitLabel(InfoSectionSymbol);
744 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfAbbrevSection());
745 if (CreateDwarfSectionSymbols) {
746 AbbrevSectionSymbol = context.CreateTempSymbol();
747 MCOS->EmitLabel(AbbrevSectionSymbol);
749 MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfARangesSection());
751 // If there are no line table entries then do not emit any section contents.
752 if (context.getMCLineSections().empty())
755 // Output the data for .debug_aranges section.
756 EmitGenDwarfAranges(MCOS, InfoSectionSymbol);
758 // Output the data for .debug_abbrev section.
759 EmitGenDwarfAbbrev(MCOS);
761 // Output the data for .debug_info section.
762 EmitGenDwarfInfo(MCOS, AbbrevSectionSymbol, LineSectionSymbol);
766 // When generating dwarf for assembly source files this is called when symbol
767 // for a label is created. If this symbol is not a temporary and is in the
768 // section that dwarf is being generated for, save the needed info to create
771 void MCGenDwarfLabelEntry::Make(MCSymbol *Symbol, MCStreamer *MCOS,
772 SourceMgr &SrcMgr, SMLoc &Loc) {
773 // We won't create dwarf labels for temporary symbols or symbols not in
775 if (Symbol->isTemporary())
777 MCContext &context = MCOS->getContext();
778 if (context.getGenDwarfSection() != MCOS->getCurrentSection().first)
781 // The dwarf label's name does not have the symbol name's leading
783 StringRef Name = Symbol->getName();
784 if (Name.startswith("_"))
785 Name = Name.substr(1, Name.size()-1);
787 // Get the dwarf file number to be used for the dwarf label.
788 unsigned FileNumber = context.getGenDwarfFileNumber();
790 // Finding the line number is the expensive part which is why we just don't
791 // pass it in as for some symbols we won't create a dwarf label.
792 int CurBuffer = SrcMgr.FindBufferContainingLoc(Loc);
793 unsigned LineNumber = SrcMgr.FindLineNumber(Loc, CurBuffer);
795 // We create a temporary symbol for use for the AT_high_pc and AT_low_pc
796 // values so that they don't have things like an ARM thumb bit from the
797 // original symbol. So when used they won't get a low bit set after
799 MCSymbol *Label = context.CreateTempSymbol();
800 MCOS->EmitLabel(Label);
802 // Create and entry for the info and add it to the other entries.
803 MCGenDwarfLabelEntry *Entry =
804 new MCGenDwarfLabelEntry(Name, FileNumber, LineNumber, Label);
805 MCOS->getContext().addMCGenDwarfLabelEntry(Entry);
808 static int getDataAlignmentFactor(MCStreamer &streamer) {
809 MCContext &context = streamer.getContext();
810 const MCAsmInfo &asmInfo = context.getAsmInfo();
811 int size = asmInfo.getCalleeSaveStackSlotSize();
812 if (asmInfo.isStackGrowthDirectionUp())
818 static unsigned getSizeForEncoding(MCStreamer &streamer,
819 unsigned symbolEncoding) {
820 MCContext &context = streamer.getContext();
821 unsigned format = symbolEncoding & 0x0f;
823 default: llvm_unreachable("Unknown Encoding");
824 case dwarf::DW_EH_PE_absptr:
825 case dwarf::DW_EH_PE_signed:
826 return context.getAsmInfo().getPointerSize();
827 case dwarf::DW_EH_PE_udata2:
828 case dwarf::DW_EH_PE_sdata2:
830 case dwarf::DW_EH_PE_udata4:
831 case dwarf::DW_EH_PE_sdata4:
833 case dwarf::DW_EH_PE_udata8:
834 case dwarf::DW_EH_PE_sdata8:
839 static void EmitSymbol(MCStreamer &streamer, const MCSymbol &symbol,
840 unsigned symbolEncoding, const char *comment = 0) {
841 MCContext &context = streamer.getContext();
842 const MCAsmInfo &asmInfo = context.getAsmInfo();
843 const MCExpr *v = asmInfo.getExprForFDESymbol(&symbol,
846 unsigned size = getSizeForEncoding(streamer, symbolEncoding);
847 if (streamer.isVerboseAsm() && comment) streamer.AddComment(comment);
848 streamer.EmitAbsValue(v, size);
851 static void EmitPersonality(MCStreamer &streamer, const MCSymbol &symbol,
852 unsigned symbolEncoding) {
853 MCContext &context = streamer.getContext();
854 const MCAsmInfo &asmInfo = context.getAsmInfo();
855 const MCExpr *v = asmInfo.getExprForPersonalitySymbol(&symbol,
858 unsigned size = getSizeForEncoding(streamer, symbolEncoding);
859 streamer.EmitValue(v, size);
863 class FrameEmitterImpl {
868 const MCSymbol *SectionStart;
870 FrameEmitterImpl(bool usingCFI, bool isEH)
871 : CFAOffset(0), CIENum(0), UsingCFI(usingCFI), IsEH(isEH),
874 void setSectionStart(const MCSymbol *Label) { SectionStart = Label; }
876 /// EmitCompactUnwind - Emit the unwind information in a compact way. If
877 /// we're successful, return 'true'. Otherwise, return 'false' and it will
878 /// emit the normal CIE and FDE.
879 void EmitCompactUnwind(MCStreamer &streamer,
880 const MCDwarfFrameInfo &frame);
882 const MCSymbol &EmitCIE(MCStreamer &streamer,
883 const MCSymbol *personality,
884 unsigned personalityEncoding,
885 const MCSymbol *lsda,
887 unsigned lsdaEncoding);
888 MCSymbol *EmitFDE(MCStreamer &streamer,
889 const MCSymbol &cieStart,
890 const MCDwarfFrameInfo &frame);
891 void EmitCFIInstructions(MCStreamer &streamer,
892 const std::vector<MCCFIInstruction> &Instrs,
893 MCSymbol *BaseLabel);
894 void EmitCFIInstruction(MCStreamer &Streamer,
895 const MCCFIInstruction &Instr);
898 } // end anonymous namespace
900 static void EmitEncodingByte(MCStreamer &Streamer, unsigned Encoding,
902 if (Streamer.isVerboseAsm()) {
905 default: EncStr = "<unknown encoding>"; break;
906 case dwarf::DW_EH_PE_absptr: EncStr = "absptr"; break;
907 case dwarf::DW_EH_PE_omit: EncStr = "omit"; break;
908 case dwarf::DW_EH_PE_pcrel: EncStr = "pcrel"; break;
909 case dwarf::DW_EH_PE_udata4: EncStr = "udata4"; break;
910 case dwarf::DW_EH_PE_udata8: EncStr = "udata8"; break;
911 case dwarf::DW_EH_PE_sdata4: EncStr = "sdata4"; break;
912 case dwarf::DW_EH_PE_sdata8: EncStr = "sdata8"; break;
913 case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata4:
914 EncStr = "pcrel udata4";
916 case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4:
917 EncStr = "pcrel sdata4";
919 case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata8:
920 EncStr = "pcrel udata8";
922 case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata8:
923 EncStr = "screl sdata8";
925 case dwarf::DW_EH_PE_indirect |dwarf::DW_EH_PE_pcrel|dwarf::DW_EH_PE_udata4:
926 EncStr = "indirect pcrel udata4";
928 case dwarf::DW_EH_PE_indirect |dwarf::DW_EH_PE_pcrel|dwarf::DW_EH_PE_sdata4:
929 EncStr = "indirect pcrel sdata4";
931 case dwarf::DW_EH_PE_indirect |dwarf::DW_EH_PE_pcrel|dwarf::DW_EH_PE_udata8:
932 EncStr = "indirect pcrel udata8";
934 case dwarf::DW_EH_PE_indirect |dwarf::DW_EH_PE_pcrel|dwarf::DW_EH_PE_sdata8:
935 EncStr = "indirect pcrel sdata8";
939 Streamer.AddComment(Twine(Prefix) + " = " + EncStr);
942 Streamer.EmitIntValue(Encoding, 1);
945 void FrameEmitterImpl::EmitCFIInstruction(MCStreamer &Streamer,
946 const MCCFIInstruction &Instr) {
947 int dataAlignmentFactor = getDataAlignmentFactor(Streamer);
948 bool VerboseAsm = Streamer.isVerboseAsm();
950 switch (Instr.getOperation()) {
951 case MCCFIInstruction::OpRegister: {
952 unsigned Reg1 = Instr.getRegister();
953 unsigned Reg2 = Instr.getRegister2();
955 Streamer.AddComment("DW_CFA_register");
956 Streamer.AddComment(Twine("Reg1 ") + Twine(Reg1));
957 Streamer.AddComment(Twine("Reg2 ") + Twine(Reg2));
959 Streamer.EmitIntValue(dwarf::DW_CFA_register, 1);
960 Streamer.EmitULEB128IntValue(Reg1);
961 Streamer.EmitULEB128IntValue(Reg2);
964 case MCCFIInstruction::OpUndefined: {
965 unsigned Reg = Instr.getRegister();
967 Streamer.AddComment("DW_CFA_undefined");
968 Streamer.AddComment(Twine("Reg ") + Twine(Reg));
970 Streamer.EmitIntValue(dwarf::DW_CFA_undefined, 1);
971 Streamer.EmitULEB128IntValue(Reg);
974 case MCCFIInstruction::OpAdjustCfaOffset:
975 case MCCFIInstruction::OpDefCfaOffset: {
976 const bool IsRelative =
977 Instr.getOperation() == MCCFIInstruction::OpAdjustCfaOffset;
980 Streamer.AddComment("DW_CFA_def_cfa_offset");
981 Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa_offset, 1);
984 CFAOffset += Instr.getOffset();
986 CFAOffset = -Instr.getOffset();
989 Streamer.AddComment(Twine("Offset " + Twine(CFAOffset)));
990 Streamer.EmitULEB128IntValue(CFAOffset);
994 case MCCFIInstruction::OpDefCfa: {
996 Streamer.AddComment("DW_CFA_def_cfa");
997 Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa, 1);
1000 Streamer.AddComment(Twine("Reg ") + Twine(Instr.getRegister()));
1001 Streamer.EmitULEB128IntValue(Instr.getRegister());
1003 CFAOffset = -Instr.getOffset();
1006 Streamer.AddComment(Twine("Offset " + Twine(CFAOffset)));
1007 Streamer.EmitULEB128IntValue(CFAOffset);
1012 case MCCFIInstruction::OpDefCfaRegister: {
1014 Streamer.AddComment("DW_CFA_def_cfa_register");
1015 Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa_register, 1);
1018 Streamer.AddComment(Twine("Reg ") + Twine(Instr.getRegister()));
1019 Streamer.EmitULEB128IntValue(Instr.getRegister());
1024 case MCCFIInstruction::OpOffset:
1025 case MCCFIInstruction::OpRelOffset: {
1026 const bool IsRelative =
1027 Instr.getOperation() == MCCFIInstruction::OpRelOffset;
1029 unsigned Reg = Instr.getRegister();
1030 int Offset = Instr.getOffset();
1032 Offset -= CFAOffset;
1033 Offset = Offset / dataAlignmentFactor;
1036 if (VerboseAsm) Streamer.AddComment("DW_CFA_offset_extended_sf");
1037 Streamer.EmitIntValue(dwarf::DW_CFA_offset_extended_sf, 1);
1038 if (VerboseAsm) Streamer.AddComment(Twine("Reg ") + Twine(Reg));
1039 Streamer.EmitULEB128IntValue(Reg);
1040 if (VerboseAsm) Streamer.AddComment(Twine("Offset ") + Twine(Offset));
1041 Streamer.EmitSLEB128IntValue(Offset);
1042 } else if (Reg < 64) {
1043 if (VerboseAsm) Streamer.AddComment(Twine("DW_CFA_offset + Reg(") +
1045 Streamer.EmitIntValue(dwarf::DW_CFA_offset + Reg, 1);
1046 if (VerboseAsm) Streamer.AddComment(Twine("Offset ") + Twine(Offset));
1047 Streamer.EmitULEB128IntValue(Offset);
1049 if (VerboseAsm) Streamer.AddComment("DW_CFA_offset_extended");
1050 Streamer.EmitIntValue(dwarf::DW_CFA_offset_extended, 1);
1051 if (VerboseAsm) Streamer.AddComment(Twine("Reg ") + Twine(Reg));
1052 Streamer.EmitULEB128IntValue(Reg);
1053 if (VerboseAsm) Streamer.AddComment(Twine("Offset ") + Twine(Offset));
1054 Streamer.EmitULEB128IntValue(Offset);
1058 case MCCFIInstruction::OpRememberState:
1059 if (VerboseAsm) Streamer.AddComment("DW_CFA_remember_state");
1060 Streamer.EmitIntValue(dwarf::DW_CFA_remember_state, 1);
1062 case MCCFIInstruction::OpRestoreState:
1063 if (VerboseAsm) Streamer.AddComment("DW_CFA_restore_state");
1064 Streamer.EmitIntValue(dwarf::DW_CFA_restore_state, 1);
1066 case MCCFIInstruction::OpSameValue: {
1067 unsigned Reg = Instr.getRegister();
1068 if (VerboseAsm) Streamer.AddComment("DW_CFA_same_value");
1069 Streamer.EmitIntValue(dwarf::DW_CFA_same_value, 1);
1070 if (VerboseAsm) Streamer.AddComment(Twine("Reg ") + Twine(Reg));
1071 Streamer.EmitULEB128IntValue(Reg);
1074 case MCCFIInstruction::OpRestore: {
1075 unsigned Reg = Instr.getRegister();
1077 Streamer.AddComment("DW_CFA_restore");
1078 Streamer.AddComment(Twine("Reg ") + Twine(Reg));
1080 Streamer.EmitIntValue(dwarf::DW_CFA_restore | Reg, 1);
1083 case MCCFIInstruction::OpEscape:
1084 if (VerboseAsm) Streamer.AddComment("Escape bytes");
1085 Streamer.EmitBytes(Instr.getValues());
1088 llvm_unreachable("Unhandled case in switch");
1091 /// EmitFrameMoves - Emit frame instructions to describe the layout of the
1093 void FrameEmitterImpl::EmitCFIInstructions(MCStreamer &streamer,
1094 const std::vector<MCCFIInstruction> &Instrs,
1095 MCSymbol *BaseLabel) {
1096 for (unsigned i = 0, N = Instrs.size(); i < N; ++i) {
1097 const MCCFIInstruction &Instr = Instrs[i];
1098 MCSymbol *Label = Instr.getLabel();
1099 // Throw out move if the label is invalid.
1100 if (Label && !Label->isDefined()) continue; // Not emitted, in dead code.
1102 // Advance row if new location.
1103 if (BaseLabel && Label) {
1104 MCSymbol *ThisSym = Label;
1105 if (ThisSym != BaseLabel) {
1106 if (streamer.isVerboseAsm()) streamer.AddComment("DW_CFA_advance_loc4");
1107 streamer.EmitDwarfAdvanceFrameAddr(BaseLabel, ThisSym);
1108 BaseLabel = ThisSym;
1112 EmitCFIInstruction(streamer, Instr);
1116 /// EmitCompactUnwind - Emit the unwind information in a compact way. If we're
1117 /// successful, return 'true'. Otherwise, return 'false' and it will emit the
1118 /// normal CIE and FDE.
1119 void FrameEmitterImpl::EmitCompactUnwind(MCStreamer &Streamer,
1120 const MCDwarfFrameInfo &Frame) {
1121 MCContext &Context = Streamer.getContext();
1122 const MCObjectFileInfo *MOFI = Context.getObjectFileInfo();
1123 bool VerboseAsm = Streamer.isVerboseAsm();
1125 // range-start range-length compact-unwind-enc personality-func lsda
1126 // _foo LfooEnd-_foo 0x00000023 0 0
1127 // _bar LbarEnd-_bar 0x00000025 __gxx_personality except_tab1
1129 // .section __LD,__compact_unwind,regular,debug
1131 // # compact unwind for _foo
1133 // .set L1,LfooEnd-_foo
1139 // # compact unwind for _bar
1141 // .set L2,LbarEnd-_bar
1144 // .quad __gxx_personality
1145 // .quad except_tab1
1147 uint32_t Encoding = Frame.CompactUnwindEncoding;
1148 if (!Encoding) return;
1149 bool DwarfEHFrameOnly = (Encoding == MOFI->getCompactUnwindDwarfEHFrameOnly());
1151 // The encoding needs to know we have an LSDA.
1152 if (!DwarfEHFrameOnly && Frame.Lsda)
1153 Encoding |= 0x40000000;
1156 unsigned FDEEncoding = MOFI->getFDEEncoding(UsingCFI);
1157 unsigned Size = getSizeForEncoding(Streamer, FDEEncoding);
1158 if (VerboseAsm) Streamer.AddComment("Range Start");
1159 Streamer.EmitSymbolValue(Frame.Function, Size);
1162 const MCExpr *Range = MakeStartMinusEndExpr(Streamer, *Frame.Begin,
1164 if (VerboseAsm) Streamer.AddComment("Range Length");
1165 Streamer.EmitAbsValue(Range, 4);
1168 Size = getSizeForEncoding(Streamer, dwarf::DW_EH_PE_udata4);
1169 if (VerboseAsm) Streamer.AddComment("Compact Unwind Encoding: 0x" +
1170 Twine::utohexstr(Encoding));
1171 Streamer.EmitIntValue(Encoding, Size);
1173 // Personality Function
1174 Size = getSizeForEncoding(Streamer, dwarf::DW_EH_PE_absptr);
1175 if (VerboseAsm) Streamer.AddComment("Personality Function");
1176 if (!DwarfEHFrameOnly && Frame.Personality)
1177 Streamer.EmitSymbolValue(Frame.Personality, Size);
1179 Streamer.EmitIntValue(0, Size); // No personality fn
1182 Size = getSizeForEncoding(Streamer, Frame.LsdaEncoding);
1183 if (VerboseAsm) Streamer.AddComment("LSDA");
1184 if (!DwarfEHFrameOnly && Frame.Lsda)
1185 Streamer.EmitSymbolValue(Frame.Lsda, Size);
1187 Streamer.EmitIntValue(0, Size); // No LSDA
1190 const MCSymbol &FrameEmitterImpl::EmitCIE(MCStreamer &streamer,
1191 const MCSymbol *personality,
1192 unsigned personalityEncoding,
1193 const MCSymbol *lsda,
1195 unsigned lsdaEncoding) {
1196 MCContext &context = streamer.getContext();
1197 const MCRegisterInfo &MRI = context.getRegisterInfo();
1198 const MCObjectFileInfo *MOFI = context.getObjectFileInfo();
1199 bool verboseAsm = streamer.isVerboseAsm();
1201 MCSymbol *sectionStart;
1202 if (MOFI->isFunctionEHFrameSymbolPrivate() || !IsEH)
1203 sectionStart = context.CreateTempSymbol();
1205 sectionStart = context.GetOrCreateSymbol(Twine("EH_frame") + Twine(CIENum));
1207 streamer.EmitLabel(sectionStart);
1210 MCSymbol *sectionEnd = context.CreateTempSymbol();
1213 const MCExpr *Length = MakeStartMinusEndExpr(streamer, *sectionStart,
1215 if (verboseAsm) streamer.AddComment("CIE Length");
1216 streamer.EmitAbsValue(Length, 4);
1219 unsigned CIE_ID = IsEH ? 0 : -1;
1220 if (verboseAsm) streamer.AddComment("CIE ID Tag");
1221 streamer.EmitIntValue(CIE_ID, 4);
1224 if (verboseAsm) streamer.AddComment("DW_CIE_VERSION");
1225 streamer.EmitIntValue(dwarf::DW_CIE_VERSION, 1);
1227 // Augmentation String
1228 SmallString<8> Augmentation;
1230 if (verboseAsm) streamer.AddComment("CIE Augmentation");
1231 Augmentation += "z";
1233 Augmentation += "P";
1235 Augmentation += "L";
1236 Augmentation += "R";
1238 Augmentation += "S";
1239 streamer.EmitBytes(Augmentation.str());
1241 streamer.EmitIntValue(0, 1);
1243 // Code Alignment Factor
1244 if (verboseAsm) streamer.AddComment("CIE Code Alignment Factor");
1245 streamer.EmitULEB128IntValue(context.getAsmInfo().getMinInstAlignment());
1247 // Data Alignment Factor
1248 if (verboseAsm) streamer.AddComment("CIE Data Alignment Factor");
1249 streamer.EmitSLEB128IntValue(getDataAlignmentFactor(streamer));
1251 // Return Address Register
1252 if (verboseAsm) streamer.AddComment("CIE Return Address Column");
1253 streamer.EmitULEB128IntValue(MRI.getDwarfRegNum(MRI.getRARegister(), true));
1255 // Augmentation Data Length (optional)
1257 unsigned augmentationLength = 0;
1260 // Personality Encoding
1261 augmentationLength += 1;
1263 augmentationLength += getSizeForEncoding(streamer, personalityEncoding);
1266 augmentationLength += 1;
1267 // Encoding of the FDE pointers
1268 augmentationLength += 1;
1270 if (verboseAsm) streamer.AddComment("Augmentation Size");
1271 streamer.EmitULEB128IntValue(augmentationLength);
1273 // Augmentation Data (optional)
1275 // Personality Encoding
1276 EmitEncodingByte(streamer, personalityEncoding,
1277 "Personality Encoding");
1279 if (verboseAsm) streamer.AddComment("Personality");
1280 EmitPersonality(streamer, *personality, personalityEncoding);
1284 EmitEncodingByte(streamer, lsdaEncoding, "LSDA Encoding");
1286 // Encoding of the FDE pointers
1287 EmitEncodingByte(streamer, MOFI->getFDEEncoding(UsingCFI),
1291 // Initial Instructions
1293 const MCAsmInfo &MAI = context.getAsmInfo();
1294 const std::vector<MCCFIInstruction> &Instructions =
1295 MAI.getInitialFrameState();
1296 EmitCFIInstructions(streamer, Instructions, NULL);
1299 streamer.EmitValueToAlignment(IsEH
1300 ? 4 : context.getAsmInfo().getPointerSize());
1302 streamer.EmitLabel(sectionEnd);
1303 return *sectionStart;
1306 MCSymbol *FrameEmitterImpl::EmitFDE(MCStreamer &streamer,
1307 const MCSymbol &cieStart,
1308 const MCDwarfFrameInfo &frame) {
1309 MCContext &context = streamer.getContext();
1310 MCSymbol *fdeStart = context.CreateTempSymbol();
1311 MCSymbol *fdeEnd = context.CreateTempSymbol();
1312 const MCObjectFileInfo *MOFI = context.getObjectFileInfo();
1313 bool verboseAsm = streamer.isVerboseAsm();
1315 if (IsEH && frame.Function && !MOFI->isFunctionEHFrameSymbolPrivate()) {
1317 context.GetOrCreateSymbol(frame.Function->getName() + Twine(".eh"));
1318 streamer.EmitEHSymAttributes(frame.Function, EHSym);
1319 streamer.EmitLabel(EHSym);
1323 const MCExpr *Length = MakeStartMinusEndExpr(streamer, *fdeStart, *fdeEnd, 0);
1324 if (verboseAsm) streamer.AddComment("FDE Length");
1325 streamer.EmitAbsValue(Length, 4);
1327 streamer.EmitLabel(fdeStart);
1330 const MCAsmInfo &asmInfo = context.getAsmInfo();
1332 const MCExpr *offset = MakeStartMinusEndExpr(streamer, cieStart, *fdeStart,
1334 if (verboseAsm) streamer.AddComment("FDE CIE Offset");
1335 streamer.EmitAbsValue(offset, 4);
1336 } else if (!asmInfo.doesDwarfUseRelocationsAcrossSections()) {
1337 const MCExpr *offset = MakeStartMinusEndExpr(streamer, *SectionStart,
1339 streamer.EmitAbsValue(offset, 4);
1341 streamer.EmitSymbolValue(&cieStart, 4);
1345 unsigned PCEncoding = IsEH ? MOFI->getFDEEncoding(UsingCFI)
1346 : (unsigned)dwarf::DW_EH_PE_absptr;
1347 unsigned PCSize = getSizeForEncoding(streamer, PCEncoding);
1348 EmitSymbol(streamer, *frame.Begin, PCEncoding, "FDE initial location");
1351 const MCExpr *Range = MakeStartMinusEndExpr(streamer, *frame.Begin,
1353 if (verboseAsm) streamer.AddComment("FDE address range");
1354 streamer.EmitAbsValue(Range, PCSize);
1357 // Augmentation Data Length
1358 unsigned augmentationLength = 0;
1361 augmentationLength += getSizeForEncoding(streamer, frame.LsdaEncoding);
1363 if (verboseAsm) streamer.AddComment("Augmentation size");
1364 streamer.EmitULEB128IntValue(augmentationLength);
1366 // Augmentation Data
1368 EmitSymbol(streamer, *frame.Lsda, frame.LsdaEncoding,
1369 "Language Specific Data Area");
1372 // Call Frame Instructions
1373 EmitCFIInstructions(streamer, frame.Instructions, frame.Begin);
1376 streamer.EmitValueToAlignment(PCSize);
1383 static const CIEKey getEmptyKey() { return CIEKey(0, 0, -1, false); }
1384 static const CIEKey getTombstoneKey() { return CIEKey(0, -1, 0, false); }
1386 CIEKey(const MCSymbol* Personality_, unsigned PersonalityEncoding_,
1387 unsigned LsdaEncoding_, bool IsSignalFrame_) :
1388 Personality(Personality_), PersonalityEncoding(PersonalityEncoding_),
1389 LsdaEncoding(LsdaEncoding_), IsSignalFrame(IsSignalFrame_) {
1391 const MCSymbol* Personality;
1392 unsigned PersonalityEncoding;
1393 unsigned LsdaEncoding;
1400 struct DenseMapInfo<CIEKey> {
1401 static CIEKey getEmptyKey() {
1402 return CIEKey::getEmptyKey();
1404 static CIEKey getTombstoneKey() {
1405 return CIEKey::getTombstoneKey();
1407 static unsigned getHashValue(const CIEKey &Key) {
1408 return static_cast<unsigned>(hash_combine(Key.Personality,
1409 Key.PersonalityEncoding,
1411 Key.IsSignalFrame));
1413 static bool isEqual(const CIEKey &LHS,
1414 const CIEKey &RHS) {
1415 return LHS.Personality == RHS.Personality &&
1416 LHS.PersonalityEncoding == RHS.PersonalityEncoding &&
1417 LHS.LsdaEncoding == RHS.LsdaEncoding &&
1418 LHS.IsSignalFrame == RHS.IsSignalFrame;
1423 void MCDwarfFrameEmitter::Emit(MCStreamer &Streamer,
1426 MCContext &Context = Streamer.getContext();
1427 const MCObjectFileInfo *MOFI = Context.getObjectFileInfo();
1428 FrameEmitterImpl Emitter(UsingCFI, IsEH);
1429 ArrayRef<MCDwarfFrameInfo> FrameArray = Streamer.getFrameInfos();
1431 // Emit the compact unwind info if available.
1432 if (IsEH && MOFI->getCompactUnwindSection()) {
1433 bool SectionEmitted = false;
1434 for (unsigned i = 0, n = FrameArray.size(); i < n; ++i) {
1435 const MCDwarfFrameInfo &Frame = FrameArray[i];
1436 if (Frame.CompactUnwindEncoding == 0) continue;
1437 if (!SectionEmitted) {
1438 Streamer.SwitchSection(MOFI->getCompactUnwindSection());
1439 Streamer.EmitValueToAlignment(Context.getAsmInfo().getPointerSize());
1440 SectionEmitted = true;
1442 Emitter.EmitCompactUnwind(Streamer, Frame);
1446 const MCSection &Section =
1447 IsEH ? *const_cast<MCObjectFileInfo*>(MOFI)->getEHFrameSection() :
1448 *MOFI->getDwarfFrameSection();
1449 Streamer.SwitchSection(&Section);
1450 MCSymbol *SectionStart = Context.CreateTempSymbol();
1451 Streamer.EmitLabel(SectionStart);
1452 Emitter.setSectionStart(SectionStart);
1454 MCSymbol *FDEEnd = NULL;
1455 DenseMap<CIEKey, const MCSymbol*> CIEStarts;
1457 const MCSymbol *DummyDebugKey = NULL;
1458 for (unsigned i = 0, n = FrameArray.size(); i < n; ++i) {
1459 const MCDwarfFrameInfo &Frame = FrameArray[i];
1460 CIEKey Key(Frame.Personality, Frame.PersonalityEncoding,
1461 Frame.LsdaEncoding, Frame.IsSignalFrame);
1462 const MCSymbol *&CIEStart = IsEH ? CIEStarts[Key] : DummyDebugKey;
1464 CIEStart = &Emitter.EmitCIE(Streamer, Frame.Personality,
1465 Frame.PersonalityEncoding, Frame.Lsda,
1466 Frame.IsSignalFrame,
1467 Frame.LsdaEncoding);
1469 FDEEnd = Emitter.EmitFDE(Streamer, *CIEStart, Frame);
1472 Streamer.EmitLabel(FDEEnd);
1475 Streamer.EmitValueToAlignment(Context.getAsmInfo().getPointerSize());
1477 Streamer.EmitLabel(FDEEnd);
1480 void MCDwarfFrameEmitter::EmitAdvanceLoc(MCStreamer &Streamer,
1481 uint64_t AddrDelta) {
1482 MCContext &Context = Streamer.getContext();
1483 SmallString<256> Tmp;
1484 raw_svector_ostream OS(Tmp);
1485 MCDwarfFrameEmitter::EncodeAdvanceLoc(Context, AddrDelta, OS);
1486 Streamer.EmitBytes(OS.str());
1489 void MCDwarfFrameEmitter::EncodeAdvanceLoc(MCContext &Context,
1492 // Scale the address delta by the minimum instruction length.
1493 AddrDelta = ScaleAddrDelta(Context, AddrDelta);
1495 if (AddrDelta == 0) {
1496 } else if (isUIntN(6, AddrDelta)) {
1497 uint8_t Opcode = dwarf::DW_CFA_advance_loc | AddrDelta;
1499 } else if (isUInt<8>(AddrDelta)) {
1500 OS << uint8_t(dwarf::DW_CFA_advance_loc1);
1501 OS << uint8_t(AddrDelta);
1502 } else if (isUInt<16>(AddrDelta)) {
1503 // FIXME: check what is the correct behavior on a big endian machine.
1504 OS << uint8_t(dwarf::DW_CFA_advance_loc2);
1505 OS << uint8_t( AddrDelta & 0xff);
1506 OS << uint8_t((AddrDelta >> 8) & 0xff);
1508 // FIXME: check what is the correct behavior on a big endian machine.
1509 assert(isUInt<32>(AddrDelta));
1510 OS << uint8_t(dwarf::DW_CFA_advance_loc4);
1511 OS << uint8_t( AddrDelta & 0xff);
1512 OS << uint8_t((AddrDelta >> 8) & 0xff);
1513 OS << uint8_t((AddrDelta >> 16) & 0xff);
1514 OS << uint8_t((AddrDelta >> 24) & 0xff);