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/StringRef.h"
19 #include "llvm/ADT/MapVector.h"
20 #include "llvm/Support/Compiler.h"
21 #include "llvm/Support/Dwarf.h"
22 #include "llvm/Support/raw_ostream.h"
35 /// MCDwarfFile - Instances of this class represent the name of the dwarf
36 /// .file directive and its associated dwarf file number in the MC file,
37 /// and MCDwarfFile's are created and unique'd by the MCContext class where
38 /// the file number for each is its index into the vector of DwarfFiles (note
39 /// index 0 is not used and not a valid dwarf file number).
41 // Name - the base name of the file without its directory path.
42 // The StringRef references memory allocated in the MCContext.
45 // DirIndex - the index into the list of directory names for this file name.
49 /// MCDwarfLoc - Instances of this class represent the information from a
50 /// dwarf .loc directive.
52 // FileNum - the file number.
54 // Line - the line number.
56 // Column - the column position.
58 // 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 /// getFileNum - Get the FileNum of this MCDwarfLoc.
86 unsigned getFileNum() const { return FileNum; }
88 /// getLine - Get the Line of this MCDwarfLoc.
89 unsigned getLine() const { return Line; }
91 /// getColumn - Get the Column of this MCDwarfLoc.
92 unsigned getColumn() const { return Column; }
94 /// getFlags - Get the Flags of this MCDwarfLoc.
95 unsigned getFlags() const { return Flags; }
97 /// getIsa - Get the Isa of this MCDwarfLoc.
98 unsigned getIsa() const { return Isa; }
100 /// getDiscriminator - Get the Discriminator of this MCDwarfLoc.
101 unsigned getDiscriminator() const { return Discriminator; }
103 /// setFileNum - Set the FileNum of this MCDwarfLoc.
104 void setFileNum(unsigned fileNum) { FileNum = fileNum; }
106 /// setLine - Set the Line of this MCDwarfLoc.
107 void setLine(unsigned line) { Line = line; }
109 /// setColumn - Set the Column of this MCDwarfLoc.
110 void setColumn(unsigned column) { Column = column; }
112 /// setFlags - Set the Flags of this MCDwarfLoc.
113 void setFlags(unsigned flags) { Flags = flags; }
115 /// setIsa - Set the Isa of this MCDwarfLoc.
116 void setIsa(unsigned isa) { Isa = isa; }
118 /// setDiscriminator - Set the Discriminator of this MCDwarfLoc.
119 void setDiscriminator(unsigned discriminator) {
120 Discriminator = discriminator;
124 /// MCLineEntry - 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(MCStreamer *MCOS, const MCSection *Section);
149 /// MCLineSection - Instances of this class represent the line information
150 /// for a compile unit where machine instructions have been assembled after seeing
151 /// .loc directives. This is the information used to build the dwarf line
152 /// table for a section.
153 class MCLineSection {
155 // addLineEntry - adds an entry to this MCLineSection's line entries
156 void addLineEntry(const MCLineEntry &LineEntry, const 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<const 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 class MCDwarfFileTable {
178 SmallVector<StringRef, 3> MCDwarfDirs;
179 SmallVector<MCDwarfFile *, 3> MCDwarfFiles;
180 MCLineSection MCLineSections;
184 // This emits the Dwarf file and the line tables for all Compile Units.
186 static const MCSymbol *Emit(MCStreamer *MCOS);
188 // This emits the Dwarf file and the line tables for a given Compile Unit.
190 const MCSymbol *EmitCU(MCStreamer *MCOS) const;
192 const SmallVectorImpl<StringRef> &getMCDwarfDirs() const {
196 SmallVectorImpl<StringRef> &getMCDwarfDirs() {
200 const SmallVectorImpl<MCDwarfFile *> &getMCDwarfFiles() const {
204 SmallVectorImpl<MCDwarfFile *> &getMCDwarfFiles() {
208 const MCLineSection &getMCLineSections() const {
209 return MCLineSections;
211 MCLineSection &getMCLineSections() {
212 return MCLineSections;
215 MCSymbol *getLabel() const {
219 void setLabel(MCSymbol *Label) {
224 class MCDwarfLineAddr {
226 /// Utility function to encode a Dwarf pair of LineDelta and AddrDeltas.
227 static void Encode(MCContext &Context, int64_t LineDelta, uint64_t AddrDelta,
230 /// Utility function to emit the encoding to a streamer.
231 static void Emit(MCStreamer *MCOS, int64_t LineDelta, uint64_t AddrDelta);
234 class MCGenDwarfInfo {
237 // When generating dwarf for assembly source files this emits the Dwarf
240 static void Emit(MCStreamer *MCOS, const MCSymbol *LineSectionSymbol);
243 // When generating dwarf for assembly source files this is the info that is
244 // needed to be gathered for each symbol that will have a dwarf label.
245 class MCGenDwarfLabelEntry {
247 // Name of the symbol without a leading underbar, if any.
249 // The dwarf file number this symbol is in.
251 // The line number this symbol is at.
253 // The low_pc for the dwarf label is taken from this symbol.
257 MCGenDwarfLabelEntry(StringRef name, unsigned fileNumber, unsigned lineNumber,
259 : Name(name), FileNumber(fileNumber), LineNumber(lineNumber),
262 StringRef getName() const { return Name; }
263 unsigned getFileNumber() const { return FileNumber; }
264 unsigned getLineNumber() const { return LineNumber; }
265 MCSymbol *getLabel() const { return Label; }
267 // This is called when label is created when we are generating dwarf for
268 // assembly source files.
269 static void Make(MCSymbol *Symbol, MCStreamer *MCOS, SourceMgr &SrcMgr,
273 class MCCFIInstruction {
300 std::vector<char> Values;
302 MCCFIInstruction(OpType Op, MCSymbol *L, unsigned R, int O, StringRef V)
303 : Operation(Op), Label(L), Register(R), Offset(O),
304 Values(V.begin(), V.end()) {
305 assert(Op != OpRegister);
308 MCCFIInstruction(OpType Op, MCSymbol *L, unsigned R1, unsigned R2)
309 : Operation(Op), Label(L), Register(R1), Register2(R2) {
310 assert(Op == OpRegister);
314 /// \brief .cfi_def_cfa defines a rule for computing CFA as: take address from
315 /// Register and add Offset to it.
316 static MCCFIInstruction createDefCfa(MCSymbol *L, unsigned Register,
318 return MCCFIInstruction(OpDefCfa, L, Register, -Offset, "");
321 /// \brief .cfi_def_cfa_register modifies a rule for computing CFA. From now
322 /// on Register will be used instead of the old one. Offset remains the same.
323 static MCCFIInstruction createDefCfaRegister(MCSymbol *L, unsigned Register) {
324 return MCCFIInstruction(OpDefCfaRegister, L, Register, 0, "");
327 /// \brief .cfi_def_cfa_offset modifies a rule for computing CFA. Register
328 /// remains the same, but offset is new. Note that it is the absolute offset
329 /// that will be added to a defined register to the compute CFA address.
330 static MCCFIInstruction createDefCfaOffset(MCSymbol *L, int Offset) {
331 return MCCFIInstruction(OpDefCfaOffset, L, 0, -Offset, "");
334 /// \brief .cfi_adjust_cfa_offset Same as .cfi_def_cfa_offset, but
335 /// Offset is a relative value that is added/subtracted from the previous
337 static MCCFIInstruction createAdjustCfaOffset(MCSymbol *L, int Adjustment) {
338 return MCCFIInstruction(OpAdjustCfaOffset, L, 0, Adjustment, "");
341 /// \brief .cfi_offset Previous value of Register is saved at offset Offset
343 static MCCFIInstruction createOffset(MCSymbol *L, unsigned Register,
345 return MCCFIInstruction(OpOffset, L, Register, Offset, "");
348 /// \brief .cfi_rel_offset Previous value of Register is saved at offset
349 /// Offset from the current CFA register. This is transformed to .cfi_offset
350 /// using the known displacement of the CFA register from the CFA.
351 static MCCFIInstruction createRelOffset(MCSymbol *L, unsigned Register,
353 return MCCFIInstruction(OpRelOffset, L, Register, Offset, "");
356 /// \brief .cfi_register Previous value of Register1 is saved in
357 /// register Register2.
358 static MCCFIInstruction createRegister(MCSymbol *L, unsigned Register1,
359 unsigned Register2) {
360 return MCCFIInstruction(OpRegister, L, Register1, Register2);
363 /// \brief .cfi_window_save SPARC register window is saved.
364 static MCCFIInstruction createWindowSave(MCSymbol *L) {
365 return MCCFIInstruction(OpWindowSave, L, 0, 0, "");
368 /// \brief .cfi_restore says that the rule for Register is now the same as it
369 /// was at the beginning of the function, after all initial instructions added
370 /// by .cfi_startproc were executed.
371 static MCCFIInstruction createRestore(MCSymbol *L, unsigned Register) {
372 return MCCFIInstruction(OpRestore, L, Register, 0, "");
375 /// \brief .cfi_undefined From now on the previous value of Register can't be
376 /// restored anymore.
377 static MCCFIInstruction createUndefined(MCSymbol *L, unsigned Register) {
378 return MCCFIInstruction(OpUndefined, L, Register, 0, "");
381 /// \brief .cfi_same_value Current value of Register is the same as in the
382 /// previous frame. I.e., no restoration is needed.
383 static MCCFIInstruction createSameValue(MCSymbol *L, unsigned Register) {
384 return MCCFIInstruction(OpSameValue, L, Register, 0, "");
387 /// \brief .cfi_remember_state Save all current rules for all registers.
388 static MCCFIInstruction createRememberState(MCSymbol *L) {
389 return MCCFIInstruction(OpRememberState, L, 0, 0, "");
392 /// \brief .cfi_restore_state Restore the previously saved state.
393 static MCCFIInstruction createRestoreState(MCSymbol *L) {
394 return MCCFIInstruction(OpRestoreState, L, 0, 0, "");
397 /// \brief .cfi_escape Allows the user to add arbitrary bytes to the unwind
399 static MCCFIInstruction createEscape(MCSymbol *L, StringRef Vals) {
400 return MCCFIInstruction(OpEscape, L, 0, 0, Vals);
403 OpType getOperation() const { return Operation; }
404 MCSymbol *getLabel() const { return Label; }
406 unsigned getRegister() const {
407 assert(Operation == OpDefCfa || Operation == OpOffset ||
408 Operation == OpRestore || Operation == OpUndefined ||
409 Operation == OpSameValue || Operation == OpDefCfaRegister ||
410 Operation == OpRelOffset || Operation == OpRegister);
414 unsigned getRegister2() const {
415 assert(Operation == OpRegister);
419 int getOffset() const {
420 assert(Operation == OpDefCfa || Operation == OpOffset ||
421 Operation == OpRelOffset || Operation == OpDefCfaOffset ||
422 Operation == OpAdjustCfaOffset);
426 const StringRef getValues() const {
427 assert(Operation == OpEscape);
428 return StringRef(&Values[0], Values.size());
432 struct MCDwarfFrameInfo {
434 : Begin(0), End(0), Personality(0), Lsda(0), Function(0), Instructions(),
435 PersonalityEncoding(), LsdaEncoding(0), CompactUnwindEncoding(0),
436 IsSignalFrame(false), IsSimple(false) {}
439 const MCSymbol *Personality;
440 const MCSymbol *Lsda;
441 const MCSymbol *Function;
442 std::vector<MCCFIInstruction> Instructions;
443 unsigned PersonalityEncoding;
444 unsigned LsdaEncoding;
445 uint32_t CompactUnwindEncoding;
450 class MCDwarfFrameEmitter {
453 // This emits the frame info section.
455 static void Emit(MCStreamer &streamer, MCAsmBackend *MAB,
456 bool usingCFI, bool isEH);
457 static void EmitAdvanceLoc(MCStreamer &Streamer, uint64_t AddrDelta);
458 static void EncodeAdvanceLoc(MCContext &Context, uint64_t AddrDelta,
461 } // end namespace llvm