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/ArrayRef.h"
19 #include "llvm/ADT/MapVector.h"
20 #include "llvm/ADT/StringMap.h"
21 #include "llvm/ADT/StringRef.h"
22 #include "llvm/Support/Compiler.h"
23 #include "llvm/Support/Dwarf.h"
24 #include "llvm/Support/raw_ostream.h"
33 class MCObjectStreamer;
40 /// \brief Instances of this class represent the name of the dwarf
41 /// .file directive and its associated dwarf file number in the MC file,
42 /// and MCDwarfFile's are created and uniqued by the MCContext class where
43 /// the file number for each is its index into the vector of DwarfFiles (note
44 /// index 0 is not used and not a valid dwarf file number).
46 // \brief The base name of the file without its directory path.
47 // The StringRef references memory allocated in the MCContext.
50 // \brief The index into the list of directory names for this file name.
54 /// \brief Instances of this class represent the information from a
55 /// dwarf .loc directive.
60 // Flags (see #define's below)
63 unsigned Discriminator;
65 // Flag that indicates the initial value of the is_stmt_start flag.
66 #define DWARF2_LINE_DEFAULT_IS_STMT 1
68 #define DWARF2_FLAG_IS_STMT (1 << 0)
69 #define DWARF2_FLAG_BASIC_BLOCK (1 << 1)
70 #define DWARF2_FLAG_PROLOGUE_END (1 << 2)
71 #define DWARF2_FLAG_EPILOGUE_BEGIN (1 << 3)
73 private: // MCContext manages these
74 friend class MCContext;
75 friend class MCLineEntry;
76 MCDwarfLoc(unsigned fileNum, unsigned line, unsigned column, unsigned flags,
77 unsigned isa, unsigned discriminator)
78 : FileNum(fileNum), Line(line), Column(column), Flags(flags), Isa(isa),
79 Discriminator(discriminator) {}
81 // Allow the default copy constructor and assignment operator to be used
82 // for an MCDwarfLoc object.
85 /// \brief Get the FileNum of this MCDwarfLoc.
86 unsigned getFileNum() const { return FileNum; }
88 /// \brief Get the Line of this MCDwarfLoc.
89 unsigned getLine() const { return Line; }
91 /// \brief Get the Column of this MCDwarfLoc.
92 unsigned getColumn() const { return Column; }
94 /// \brief Get the Flags of this MCDwarfLoc.
95 unsigned getFlags() const { return Flags; }
97 /// \brief Get the Isa of this MCDwarfLoc.
98 unsigned getIsa() const { return Isa; }
100 /// \brief Get the Discriminator of this MCDwarfLoc.
101 unsigned getDiscriminator() const { return Discriminator; }
103 /// \brief Set the FileNum of this MCDwarfLoc.
104 void setFileNum(unsigned fileNum) { FileNum = fileNum; }
106 /// \brief Set the Line of this MCDwarfLoc.
107 void setLine(unsigned line) { Line = line; }
109 /// \brief Set the Column of this MCDwarfLoc.
110 void setColumn(unsigned column) { Column = column; }
112 /// \brief Set the Flags of this MCDwarfLoc.
113 void setFlags(unsigned flags) { Flags = flags; }
115 /// \brief Set the Isa of this MCDwarfLoc.
116 void setIsa(unsigned isa) { Isa = isa; }
118 /// \brief Set the Discriminator of this MCDwarfLoc.
119 void setDiscriminator(unsigned discriminator) {
120 Discriminator = discriminator;
124 /// \brief Instances of this class represent the line information for
125 /// the dwarf line table entries. Which is created after a machine
126 /// instruction is assembled and uses an address from a temporary label
127 /// created at the current address in the current section and the info from
128 /// the last .loc directive seen as stored in the context.
129 class MCLineEntry : public MCDwarfLoc {
133 // Allow the default copy constructor and assignment operator to be used
134 // for an MCLineEntry object.
137 // Constructor to create an MCLineEntry given a symbol and the dwarf loc.
138 MCLineEntry(MCSymbol *label, const MCDwarfLoc loc)
139 : MCDwarfLoc(loc), Label(label) {}
141 MCSymbol *getLabel() const { return Label; }
143 // This is called when an instruction is assembled into the specified
144 // section and if there is information from the last .loc directive that
145 // has yet to have a line entry made for it is made.
146 static void Make(MCObjectStreamer *MCOS, MCSection *Section);
149 /// \brief Instances of this class represent the line information for a compile
150 /// unit where machine instructions have been assembled after seeing .loc
151 /// directives. This is the information used to build the dwarf line
152 /// table for a section.
153 class MCLineSection {
155 // \brief Add an entry to this MCLineSection's line entries.
156 void addLineEntry(const MCLineEntry &LineEntry, MCSection *Sec) {
157 MCLineDivisions[Sec].push_back(LineEntry);
160 typedef std::vector<MCLineEntry> MCLineEntryCollection;
161 typedef MCLineEntryCollection::iterator iterator;
162 typedef MCLineEntryCollection::const_iterator const_iterator;
163 typedef MapVector<MCSection *, MCLineEntryCollection> MCLineDivisionMap;
166 // A collection of MCLineEntry for each section.
167 MCLineDivisionMap MCLineDivisions;
170 // Returns the collection of MCLineEntry for a given Compile Unit ID.
171 const MCLineDivisionMap &getMCLineEntries() const {
172 return MCLineDivisions;
176 struct MCDwarfLineTableHeader {
178 SmallVector<std::string, 3> MCDwarfDirs;
179 SmallVector<MCDwarfFile, 3> MCDwarfFiles;
180 StringMap<unsigned> SourceIdMap;
181 StringRef CompilationDir;
183 MCDwarfLineTableHeader() : Label(nullptr) {}
184 unsigned getFile(StringRef &Directory, StringRef &FileName,
185 unsigned FileNumber = 0);
186 std::pair<MCSymbol *, MCSymbol *> Emit(MCStreamer *MCOS) const;
187 std::pair<MCSymbol *, MCSymbol *>
188 Emit(MCStreamer *MCOS, ArrayRef<char> SpecialOpcodeLengths) const;
191 class MCDwarfDwoLineTable {
192 MCDwarfLineTableHeader Header;
194 void setCompilationDir(StringRef CompilationDir) {
195 Header.CompilationDir = CompilationDir;
197 unsigned getFile(StringRef Directory, StringRef FileName) {
198 return Header.getFile(Directory, FileName);
200 void Emit(MCStreamer &MCOS) const;
203 class MCDwarfLineTable {
204 MCDwarfLineTableHeader Header;
205 MCLineSection MCLineSections;
208 // This emits the Dwarf file and the line tables for all Compile Units.
209 static void Emit(MCObjectStreamer *MCOS);
211 // This emits the Dwarf file and the line tables for a given Compile Unit.
212 void EmitCU(MCObjectStreamer *MCOS) const;
214 unsigned getFile(StringRef &Directory, StringRef &FileName,
215 unsigned FileNumber = 0);
217 MCSymbol *getLabel() const {
221 void setLabel(MCSymbol *Label) {
222 Header.Label = Label;
225 void setCompilationDir(StringRef CompilationDir) {
226 Header.CompilationDir = CompilationDir;
229 const SmallVectorImpl<std::string> &getMCDwarfDirs() const {
230 return Header.MCDwarfDirs;
233 SmallVectorImpl<std::string> &getMCDwarfDirs() {
234 return Header.MCDwarfDirs;
237 const SmallVectorImpl<MCDwarfFile> &getMCDwarfFiles() const {
238 return Header.MCDwarfFiles;
241 SmallVectorImpl<MCDwarfFile> &getMCDwarfFiles() {
242 return Header.MCDwarfFiles;
245 const MCLineSection &getMCLineSections() const {
246 return MCLineSections;
248 MCLineSection &getMCLineSections() {
249 return MCLineSections;
253 class MCDwarfLineAddr {
255 /// Utility function to encode a Dwarf pair of LineDelta and AddrDeltas.
256 static void Encode(MCContext &Context, int64_t LineDelta, uint64_t AddrDelta,
259 /// Utility function to emit the encoding to a streamer.
260 static void Emit(MCStreamer *MCOS, int64_t LineDelta, uint64_t AddrDelta);
263 class MCGenDwarfInfo {
266 // When generating dwarf for assembly source files this emits the Dwarf
269 static void Emit(MCStreamer *MCOS);
272 // When generating dwarf for assembly source files this is the info that is
273 // needed to be gathered for each symbol that will have a dwarf label.
274 class MCGenDwarfLabelEntry {
276 // Name of the symbol without a leading underbar, if any.
278 // The dwarf file number this symbol is in.
280 // The line number this symbol is at.
282 // The low_pc for the dwarf label is taken from this symbol.
286 MCGenDwarfLabelEntry(StringRef name, unsigned fileNumber, unsigned lineNumber,
288 : Name(name), FileNumber(fileNumber), LineNumber(lineNumber),
291 StringRef getName() const { return Name; }
292 unsigned getFileNumber() const { return FileNumber; }
293 unsigned getLineNumber() const { return LineNumber; }
294 MCSymbol *getLabel() const { return Label; }
296 // This is called when label is created when we are generating dwarf for
297 // assembly source files.
298 static void Make(MCSymbol *Symbol, MCStreamer *MCOS, SourceMgr &SrcMgr,
302 class MCCFIInstruction {
329 std::vector<char> Values;
331 MCCFIInstruction(OpType Op, MCSymbol *L, unsigned R, int O, StringRef V)
332 : Operation(Op), Label(L), Register(R), Offset(O),
333 Values(V.begin(), V.end()) {
334 assert(Op != OpRegister);
337 MCCFIInstruction(OpType Op, MCSymbol *L, unsigned R1, unsigned R2)
338 : Operation(Op), Label(L), Register(R1), Register2(R2) {
339 assert(Op == OpRegister);
343 /// \brief .cfi_def_cfa defines a rule for computing CFA as: take address from
344 /// Register and add Offset to it.
345 static MCCFIInstruction createDefCfa(MCSymbol *L, unsigned Register,
347 return MCCFIInstruction(OpDefCfa, L, Register, -Offset, "");
350 /// \brief .cfi_def_cfa_register modifies a rule for computing CFA. From now
351 /// on Register will be used instead of the old one. Offset remains the same.
352 static MCCFIInstruction createDefCfaRegister(MCSymbol *L, unsigned Register) {
353 return MCCFIInstruction(OpDefCfaRegister, L, Register, 0, "");
356 /// \brief .cfi_def_cfa_offset modifies a rule for computing CFA. Register
357 /// remains the same, but offset is new. Note that it is the absolute offset
358 /// that will be added to a defined register to the compute CFA address.
359 static MCCFIInstruction createDefCfaOffset(MCSymbol *L, int Offset) {
360 return MCCFIInstruction(OpDefCfaOffset, L, 0, -Offset, "");
363 /// \brief .cfi_adjust_cfa_offset Same as .cfi_def_cfa_offset, but
364 /// Offset is a relative value that is added/subtracted from the previous
366 static MCCFIInstruction createAdjustCfaOffset(MCSymbol *L, int Adjustment) {
367 return MCCFIInstruction(OpAdjustCfaOffset, L, 0, Adjustment, "");
370 /// \brief .cfi_offset Previous value of Register is saved at offset Offset
372 static MCCFIInstruction createOffset(MCSymbol *L, unsigned Register,
374 return MCCFIInstruction(OpOffset, L, Register, Offset, "");
377 /// \brief .cfi_rel_offset Previous value of Register is saved at offset
378 /// Offset from the current CFA register. This is transformed to .cfi_offset
379 /// using the known displacement of the CFA register from the CFA.
380 static MCCFIInstruction createRelOffset(MCSymbol *L, unsigned Register,
382 return MCCFIInstruction(OpRelOffset, L, Register, Offset, "");
385 /// \brief .cfi_register Previous value of Register1 is saved in
386 /// register Register2.
387 static MCCFIInstruction createRegister(MCSymbol *L, unsigned Register1,
388 unsigned Register2) {
389 return MCCFIInstruction(OpRegister, L, Register1, Register2);
392 /// \brief .cfi_window_save SPARC register window is saved.
393 static MCCFIInstruction createWindowSave(MCSymbol *L) {
394 return MCCFIInstruction(OpWindowSave, L, 0, 0, "");
397 /// \brief .cfi_restore says that the rule for Register is now the same as it
398 /// was at the beginning of the function, after all initial instructions added
399 /// by .cfi_startproc were executed.
400 static MCCFIInstruction createRestore(MCSymbol *L, unsigned Register) {
401 return MCCFIInstruction(OpRestore, L, Register, 0, "");
404 /// \brief .cfi_undefined From now on the previous value of Register can't be
405 /// restored anymore.
406 static MCCFIInstruction createUndefined(MCSymbol *L, unsigned Register) {
407 return MCCFIInstruction(OpUndefined, L, Register, 0, "");
410 /// \brief .cfi_same_value Current value of Register is the same as in the
411 /// previous frame. I.e., no restoration is needed.
412 static MCCFIInstruction createSameValue(MCSymbol *L, unsigned Register) {
413 return MCCFIInstruction(OpSameValue, L, Register, 0, "");
416 /// \brief .cfi_remember_state Save all current rules for all registers.
417 static MCCFIInstruction createRememberState(MCSymbol *L) {
418 return MCCFIInstruction(OpRememberState, L, 0, 0, "");
421 /// \brief .cfi_restore_state Restore the previously saved state.
422 static MCCFIInstruction createRestoreState(MCSymbol *L) {
423 return MCCFIInstruction(OpRestoreState, L, 0, 0, "");
426 /// \brief .cfi_escape Allows the user to add arbitrary bytes to the unwind
428 static MCCFIInstruction createEscape(MCSymbol *L, StringRef Vals) {
429 return MCCFIInstruction(OpEscape, L, 0, 0, Vals);
432 OpType getOperation() const { return Operation; }
433 MCSymbol *getLabel() const { return Label; }
435 unsigned getRegister() const {
436 assert(Operation == OpDefCfa || Operation == OpOffset ||
437 Operation == OpRestore || Operation == OpUndefined ||
438 Operation == OpSameValue || Operation == OpDefCfaRegister ||
439 Operation == OpRelOffset || Operation == OpRegister);
443 unsigned getRegister2() const {
444 assert(Operation == OpRegister);
448 int getOffset() const {
449 assert(Operation == OpDefCfa || Operation == OpOffset ||
450 Operation == OpRelOffset || Operation == OpDefCfaOffset ||
451 Operation == OpAdjustCfaOffset);
455 StringRef getValues() const {
456 assert(Operation == OpEscape);
457 return StringRef(&Values[0], Values.size());
461 struct MCDwarfFrameInfo {
463 : Begin(nullptr), End(nullptr), Personality(nullptr), Lsda(nullptr),
464 Instructions(), CurrentCfaRegister(0), PersonalityEncoding(),
465 LsdaEncoding(0), CompactUnwindEncoding(0), IsSignalFrame(false),
469 const MCSymbol *Personality;
470 const MCSymbol *Lsda;
471 std::vector<MCCFIInstruction> Instructions;
472 unsigned CurrentCfaRegister;
473 unsigned PersonalityEncoding;
474 unsigned LsdaEncoding;
475 uint32_t CompactUnwindEncoding;
480 class MCDwarfFrameEmitter {
483 // This emits the frame info section.
485 static void Emit(MCObjectStreamer &streamer, MCAsmBackend *MAB, bool isEH);
486 static void EmitAdvanceLoc(MCObjectStreamer &Streamer, uint64_t AddrDelta);
487 static void EncodeAdvanceLoc(MCContext &Context, uint64_t AddrDelta,
490 } // end namespace llvm