1 //===- MCDwarf.h - Machine Code Dwarf support -------------------*- C++ -*-===//
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 // This file contains the declaration of the MCDwarfFile to support the dwarf
11 // .file directive and the .loc directive.
13 //===----------------------------------------------------------------------===//
15 #ifndef LLVM_MC_MCDWARF_H
16 #define LLVM_MC_MCDWARF_H
18 #include "llvm/ADT/MapVector.h"
19 #include "llvm/ADT/Optional.h"
20 #include "llvm/ADT/SmallVector.h"
21 #include "llvm/ADT/StringMap.h"
22 #include "llvm/ADT/StringRef.h"
23 #include "llvm/MC/MCSection.h"
24 #include "llvm/Support/Error.h"
25 #include "llvm/Support/MD5.h"
34 template <typename T> class ArrayRef;
38 class MCObjectStreamer;
45 /// Instances of this class represent the name of the dwarf
46 /// .file directive and its associated dwarf file number in the MC file,
47 /// and MCDwarfFile's are created and uniqued by the MCContext class where
48 /// the file number for each is its index into the vector of DwarfFiles (note
49 /// index 0 is not used and not a valid dwarf file number).
51 // The base name of the file without its directory path.
54 // The index into the list of directory names for this file name.
57 /// The MD5 checksum, if there is one. Non-owning pointer to data allocated
59 MD5::MD5Result *Checksum = nullptr;
61 /// The source code of the file. Non-owning reference to data allocated in
63 Optional<StringRef> Source;
66 /// Instances of this class represent the information from a
67 /// dwarf .loc directive.
72 // Flags (see #define's below)
75 uint32_t Discriminator;
77 // Flag that indicates the initial value of the is_stmt_start flag.
78 #define DWARF2_LINE_DEFAULT_IS_STMT 1
80 #define DWARF2_FLAG_IS_STMT (1 << 0)
81 #define DWARF2_FLAG_BASIC_BLOCK (1 << 1)
82 #define DWARF2_FLAG_PROLOGUE_END (1 << 2)
83 #define DWARF2_FLAG_EPILOGUE_BEGIN (1 << 3)
85 private: // MCContext manages these
86 friend class MCContext;
87 friend class MCDwarfLineEntry;
89 MCDwarfLoc(unsigned fileNum, unsigned line, unsigned column, unsigned flags,
90 unsigned isa, unsigned discriminator)
91 : FileNum(fileNum), Line(line), Column(column), Flags(flags), Isa(isa),
92 Discriminator(discriminator) {}
94 // Allow the default copy constructor and assignment operator to be used
95 // for an MCDwarfLoc object.
98 /// Get the FileNum of this MCDwarfLoc.
99 unsigned getFileNum() const { return FileNum; }
101 /// Get the Line of this MCDwarfLoc.
102 unsigned getLine() const { return Line; }
104 /// Get the Column of this MCDwarfLoc.
105 unsigned getColumn() const { return Column; }
107 /// Get the Flags of this MCDwarfLoc.
108 unsigned getFlags() const { return Flags; }
110 /// Get the Isa of this MCDwarfLoc.
111 unsigned getIsa() const { return Isa; }
113 /// Get the Discriminator of this MCDwarfLoc.
114 unsigned getDiscriminator() const { return Discriminator; }
116 /// Set the FileNum of this MCDwarfLoc.
117 void setFileNum(unsigned fileNum) { FileNum = fileNum; }
119 /// Set the Line of this MCDwarfLoc.
120 void setLine(unsigned line) { Line = line; }
122 /// Set the Column of this MCDwarfLoc.
123 void setColumn(unsigned column) {
124 assert(column <= UINT16_MAX);
128 /// Set the Flags of this MCDwarfLoc.
129 void setFlags(unsigned flags) {
130 assert(flags <= UINT8_MAX);
134 /// Set the Isa of this MCDwarfLoc.
135 void setIsa(unsigned isa) {
136 assert(isa <= UINT8_MAX);
140 /// Set the Discriminator of this MCDwarfLoc.
141 void setDiscriminator(unsigned discriminator) {
142 Discriminator = discriminator;
146 /// Instances of this class represent the line information for
147 /// the dwarf line table entries. Which is created after a machine
148 /// instruction is assembled and uses an address from a temporary label
149 /// created at the current address in the current section and the info from
150 /// the last .loc directive seen as stored in the context.
151 class MCDwarfLineEntry : public MCDwarfLoc {
155 // Allow the default copy constructor and assignment operator to be used
156 // for an MCDwarfLineEntry object.
159 // Constructor to create an MCDwarfLineEntry given a symbol and the dwarf loc.
160 MCDwarfLineEntry(MCSymbol *label, const MCDwarfLoc loc)
161 : MCDwarfLoc(loc), Label(label) {}
163 MCSymbol *getLabel() const { return Label; }
165 // This is called when an instruction is assembled into the specified
166 // section and if there is information from the last .loc directive that
167 // has yet to have a line entry made for it is made.
168 static void Make(MCObjectStreamer *MCOS, MCSection *Section);
171 /// Instances of this class represent the line information for a compile
172 /// unit where machine instructions have been assembled after seeing .loc
173 /// directives. This is the information used to build the dwarf line
174 /// table for a section.
175 class MCLineSection {
177 // Add an entry to this MCLineSection's line entries.
178 void addLineEntry(const MCDwarfLineEntry &LineEntry, MCSection *Sec) {
179 MCLineDivisions[Sec].push_back(LineEntry);
182 using MCDwarfLineEntryCollection = std::vector<MCDwarfLineEntry>;
183 using iterator = MCDwarfLineEntryCollection::iterator;
184 using const_iterator = MCDwarfLineEntryCollection::const_iterator;
185 using MCLineDivisionMap = MapVector<MCSection *, MCDwarfLineEntryCollection>;
188 // A collection of MCDwarfLineEntry for each section.
189 MCLineDivisionMap MCLineDivisions;
192 // Returns the collection of MCDwarfLineEntry for a given Compile Unit ID.
193 const MCLineDivisionMap &getMCLineEntries() const {
194 return MCLineDivisions;
198 struct MCDwarfLineTableParams {
199 /// First special line opcode - leave room for the standard opcodes.
200 /// Note: If you want to change this, you'll have to update the
201 /// "StandardOpcodeLengths" table that is emitted in
203 uint8_t DWARF2LineOpcodeBase = 13;
204 /// Minimum line offset in a special line info. opcode. The value
205 /// -5 was chosen to give a reasonable range of values.
206 int8_t DWARF2LineBase = -5;
207 /// Range of line offsets in a special line info. opcode.
208 uint8_t DWARF2LineRange = 14;
211 struct MCDwarfLineTableHeader {
212 MCSymbol *Label = nullptr;
213 SmallVector<std::string, 3> MCDwarfDirs;
214 SmallVector<MCDwarfFile, 3> MCDwarfFiles;
215 StringMap<unsigned> SourceIdMap;
216 std::string CompilationDir;
217 MCDwarfFile RootFile;
218 bool HasSource = false;
220 bool HasAllMD5 = true;
221 bool HasAnyMD5 = false;
224 MCDwarfLineTableHeader() = default;
226 Expected<unsigned> tryGetFile(StringRef &Directory, StringRef &FileName,
227 MD5::MD5Result *Checksum,
228 Optional<StringRef> &Source,
229 unsigned FileNumber = 0);
230 std::pair<MCSymbol *, MCSymbol *>
231 Emit(MCStreamer *MCOS, MCDwarfLineTableParams Params,
232 Optional<MCDwarfLineStr> &LineStr) const;
233 std::pair<MCSymbol *, MCSymbol *>
234 Emit(MCStreamer *MCOS, MCDwarfLineTableParams Params,
235 ArrayRef<char> SpecialOpcodeLengths,
236 Optional<MCDwarfLineStr> &LineStr) const;
237 void resetMD5Usage() {
241 void trackMD5Usage(bool MD5Used) {
242 HasAllMD5 &= MD5Used;
243 HasAnyMD5 |= MD5Used;
245 bool isMD5UsageConsistent() const {
246 return MCDwarfFiles.empty() || (HasAllMD5 == HasAnyMD5);
250 void emitV2FileDirTables(MCStreamer *MCOS) const;
251 void emitV5FileDirTables(MCStreamer *MCOS, Optional<MCDwarfLineStr> &LineStr,
252 StringRef CtxCompilationDir) const;
255 class MCDwarfDwoLineTable {
256 MCDwarfLineTableHeader Header;
259 void maybeSetRootFile(StringRef Directory, StringRef FileName,
260 MD5::MD5Result *Checksum, Optional<StringRef> Source) {
261 if (!Header.RootFile.Name.empty())
263 Header.CompilationDir = Directory;
264 Header.RootFile.Name = FileName;
265 Header.RootFile.DirIndex = 0;
266 Header.RootFile.Checksum = Checksum;
267 Header.RootFile.Source = Source;
268 Header.trackMD5Usage(Checksum);
269 Header.HasSource = Source.hasValue();
272 unsigned getFile(StringRef Directory, StringRef FileName,
273 MD5::MD5Result *Checksum, Optional<StringRef> Source) {
274 return cantFail(Header.tryGetFile(Directory, FileName, Checksum, Source));
277 void Emit(MCStreamer &MCOS, MCDwarfLineTableParams Params,
278 MCSection *Section) const;
281 class MCDwarfLineTable {
282 MCDwarfLineTableHeader Header;
283 MCLineSection MCLineSections;
286 // This emits the Dwarf file and the line tables for all Compile Units.
287 static void Emit(MCObjectStreamer *MCOS, MCDwarfLineTableParams Params);
289 // This emits the Dwarf file and the line tables for a given Compile Unit.
290 void EmitCU(MCObjectStreamer *MCOS, MCDwarfLineTableParams Params,
291 Optional<MCDwarfLineStr> &LineStr) const;
293 Expected<unsigned> tryGetFile(StringRef &Directory, StringRef &FileName,
294 MD5::MD5Result *Checksum,
295 Optional<StringRef> Source,
296 unsigned FileNumber = 0);
297 unsigned getFile(StringRef &Directory, StringRef &FileName,
298 MD5::MD5Result *Checksum, Optional<StringRef> &Source,
299 unsigned FileNumber = 0) {
300 return cantFail(tryGetFile(Directory, FileName, Checksum, Source,
304 void setRootFile(StringRef Directory, StringRef FileName,
305 MD5::MD5Result *Checksum, Optional<StringRef> Source) {
306 Header.CompilationDir = Directory;
307 Header.RootFile.Name = FileName;
308 Header.RootFile.DirIndex = 0;
309 Header.RootFile.Checksum = Checksum;
310 Header.RootFile.Source = Source;
311 Header.trackMD5Usage(Checksum);
312 Header.HasSource = Source.hasValue();
315 void resetRootFile() {
316 assert(Header.MCDwarfFiles.empty());
317 Header.RootFile.Name.clear();
318 Header.resetMD5Usage();
319 Header.HasSource = false;
322 bool hasRootFile() const { return !Header.RootFile.Name.empty(); }
324 // Report whether MD5 usage has been consistent (all-or-none).
325 bool isMD5UsageConsistent() const { return Header.isMD5UsageConsistent(); }
327 MCSymbol *getLabel() const {
331 void setLabel(MCSymbol *Label) {
332 Header.Label = Label;
335 const SmallVectorImpl<std::string> &getMCDwarfDirs() const {
336 return Header.MCDwarfDirs;
339 SmallVectorImpl<std::string> &getMCDwarfDirs() {
340 return Header.MCDwarfDirs;
343 const SmallVectorImpl<MCDwarfFile> &getMCDwarfFiles() const {
344 return Header.MCDwarfFiles;
347 SmallVectorImpl<MCDwarfFile> &getMCDwarfFiles() {
348 return Header.MCDwarfFiles;
351 const MCLineSection &getMCLineSections() const {
352 return MCLineSections;
354 MCLineSection &getMCLineSections() {
355 return MCLineSections;
359 class MCDwarfLineAddr {
361 /// Utility function to encode a Dwarf pair of LineDelta and AddrDeltas.
362 static void Encode(MCContext &Context, MCDwarfLineTableParams Params,
363 int64_t LineDelta, uint64_t AddrDelta, raw_ostream &OS);
365 /// Utility function to encode a Dwarf pair of LineDelta and AddrDeltas using
366 /// fixed length operands.
367 static bool FixedEncode(MCContext &Context,
368 MCDwarfLineTableParams Params,
369 int64_t LineDelta, uint64_t AddrDelta,
370 raw_ostream &OS, uint32_t *Offset, uint32_t *Size);
372 /// Utility function to emit the encoding to a streamer.
373 static void Emit(MCStreamer *MCOS, MCDwarfLineTableParams Params,
374 int64_t LineDelta, uint64_t AddrDelta);
377 class MCGenDwarfInfo {
380 // When generating dwarf for assembly source files this emits the Dwarf
383 static void Emit(MCStreamer *MCOS);
386 // When generating dwarf for assembly source files this is the info that is
387 // needed to be gathered for each symbol that will have a dwarf label.
388 class MCGenDwarfLabelEntry {
390 // Name of the symbol without a leading underbar, if any.
392 // The dwarf file number this symbol is in.
394 // The line number this symbol is at.
396 // The low_pc for the dwarf label is taken from this symbol.
400 MCGenDwarfLabelEntry(StringRef name, unsigned fileNumber, unsigned lineNumber,
402 : Name(name), FileNumber(fileNumber), LineNumber(lineNumber),
405 StringRef getName() const { return Name; }
406 unsigned getFileNumber() const { return FileNumber; }
407 unsigned getLineNumber() const { return LineNumber; }
408 MCSymbol *getLabel() const { return Label; }
410 // This is called when label is created when we are generating dwarf for
411 // assembly source files.
412 static void Make(MCSymbol *Symbol, MCStreamer *MCOS, SourceMgr &SrcMgr,
416 class MCCFIInstruction {
445 std::vector<char> Values;
447 MCCFIInstruction(OpType Op, MCSymbol *L, unsigned R, int O, StringRef V)
448 : Operation(Op), Label(L), Register(R), Offset(O),
449 Values(V.begin(), V.end()) {
450 assert(Op != OpRegister);
453 MCCFIInstruction(OpType Op, MCSymbol *L, unsigned R1, unsigned R2)
454 : Operation(Op), Label(L), Register(R1), Register2(R2) {
455 assert(Op == OpRegister);
459 /// .cfi_def_cfa defines a rule for computing CFA as: take address from
460 /// Register and add Offset to it.
461 static MCCFIInstruction createDefCfa(MCSymbol *L, unsigned Register,
463 return MCCFIInstruction(OpDefCfa, L, Register, -Offset, "");
466 /// .cfi_def_cfa_register modifies a rule for computing CFA. From now
467 /// on Register will be used instead of the old one. Offset remains the same.
468 static MCCFIInstruction createDefCfaRegister(MCSymbol *L, unsigned Register) {
469 return MCCFIInstruction(OpDefCfaRegister, L, Register, 0, "");
472 /// .cfi_def_cfa_offset modifies a rule for computing CFA. Register
473 /// remains the same, but offset is new. Note that it is the absolute offset
474 /// that will be added to a defined register to the compute CFA address.
475 static MCCFIInstruction createDefCfaOffset(MCSymbol *L, int Offset) {
476 return MCCFIInstruction(OpDefCfaOffset, L, 0, -Offset, "");
479 /// .cfi_adjust_cfa_offset Same as .cfi_def_cfa_offset, but
480 /// Offset is a relative value that is added/subtracted from the previous
482 static MCCFIInstruction createAdjustCfaOffset(MCSymbol *L, int Adjustment) {
483 return MCCFIInstruction(OpAdjustCfaOffset, L, 0, Adjustment, "");
486 /// .cfi_offset Previous value of Register is saved at offset Offset
488 static MCCFIInstruction createOffset(MCSymbol *L, unsigned Register,
490 return MCCFIInstruction(OpOffset, L, Register, Offset, "");
493 /// .cfi_rel_offset Previous value of Register is saved at offset
494 /// Offset from the current CFA register. This is transformed to .cfi_offset
495 /// using the known displacement of the CFA register from the CFA.
496 static MCCFIInstruction createRelOffset(MCSymbol *L, unsigned Register,
498 return MCCFIInstruction(OpRelOffset, L, Register, Offset, "");
501 /// .cfi_register Previous value of Register1 is saved in
502 /// register Register2.
503 static MCCFIInstruction createRegister(MCSymbol *L, unsigned Register1,
504 unsigned Register2) {
505 return MCCFIInstruction(OpRegister, L, Register1, Register2);
508 /// .cfi_window_save SPARC register window is saved.
509 static MCCFIInstruction createWindowSave(MCSymbol *L) {
510 return MCCFIInstruction(OpWindowSave, L, 0, 0, "");
513 /// .cfi_negate_ra_state AArch64 negate RA state.
514 static MCCFIInstruction createNegateRAState(MCSymbol *L) {
515 return MCCFIInstruction(OpNegateRAState, L, 0, 0, "");
518 /// .cfi_restore says that the rule for Register is now the same as it
519 /// was at the beginning of the function, after all initial instructions added
520 /// by .cfi_startproc were executed.
521 static MCCFIInstruction createRestore(MCSymbol *L, unsigned Register) {
522 return MCCFIInstruction(OpRestore, L, Register, 0, "");
525 /// .cfi_undefined From now on the previous value of Register can't be
526 /// restored anymore.
527 static MCCFIInstruction createUndefined(MCSymbol *L, unsigned Register) {
528 return MCCFIInstruction(OpUndefined, L, Register, 0, "");
531 /// .cfi_same_value Current value of Register is the same as in the
532 /// previous frame. I.e., no restoration is needed.
533 static MCCFIInstruction createSameValue(MCSymbol *L, unsigned Register) {
534 return MCCFIInstruction(OpSameValue, L, Register, 0, "");
537 /// .cfi_remember_state Save all current rules for all registers.
538 static MCCFIInstruction createRememberState(MCSymbol *L) {
539 return MCCFIInstruction(OpRememberState, L, 0, 0, "");
542 /// .cfi_restore_state Restore the previously saved state.
543 static MCCFIInstruction createRestoreState(MCSymbol *L) {
544 return MCCFIInstruction(OpRestoreState, L, 0, 0, "");
547 /// .cfi_escape Allows the user to add arbitrary bytes to the unwind
549 static MCCFIInstruction createEscape(MCSymbol *L, StringRef Vals) {
550 return MCCFIInstruction(OpEscape, L, 0, 0, Vals);
553 /// A special wrapper for .cfi_escape that indicates GNU_ARGS_SIZE
554 static MCCFIInstruction createGnuArgsSize(MCSymbol *L, int Size) {
555 return MCCFIInstruction(OpGnuArgsSize, L, 0, Size, "");
558 OpType getOperation() const { return Operation; }
559 MCSymbol *getLabel() const { return Label; }
561 unsigned getRegister() const {
562 assert(Operation == OpDefCfa || Operation == OpOffset ||
563 Operation == OpRestore || Operation == OpUndefined ||
564 Operation == OpSameValue || Operation == OpDefCfaRegister ||
565 Operation == OpRelOffset || Operation == OpRegister);
569 unsigned getRegister2() const {
570 assert(Operation == OpRegister);
574 int getOffset() const {
575 assert(Operation == OpDefCfa || Operation == OpOffset ||
576 Operation == OpRelOffset || Operation == OpDefCfaOffset ||
577 Operation == OpAdjustCfaOffset || Operation == OpGnuArgsSize);
581 StringRef getValues() const {
582 assert(Operation == OpEscape);
583 return StringRef(&Values[0], Values.size());
587 struct MCDwarfFrameInfo {
588 MCDwarfFrameInfo() = default;
590 MCSymbol *Begin = nullptr;
591 MCSymbol *End = nullptr;
592 const MCSymbol *Personality = nullptr;
593 const MCSymbol *Lsda = nullptr;
594 std::vector<MCCFIInstruction> Instructions;
595 unsigned CurrentCfaRegister = 0;
596 unsigned PersonalityEncoding = 0;
597 unsigned LsdaEncoding = 0;
598 uint32_t CompactUnwindEncoding = 0;
599 bool IsSignalFrame = false;
600 bool IsSimple = false;
601 unsigned RAReg = static_cast<unsigned>(INT_MAX);
602 bool IsBKeyFrame = false;
605 class MCDwarfFrameEmitter {
608 // This emits the frame info section.
610 static void Emit(MCObjectStreamer &streamer, MCAsmBackend *MAB, bool isEH);
611 static void EmitAdvanceLoc(MCObjectStreamer &Streamer, uint64_t AddrDelta);
612 static void EncodeAdvanceLoc(MCContext &Context, uint64_t AddrDelta,
616 } // end namespace llvm
618 #endif // LLVM_MC_MCDWARF_H