1 //===-- llvm/CodeGen/DwarfDebug.h - Dwarf Debug Framework ------*- 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 support for writing dwarf debug info into asm files.
12 //===----------------------------------------------------------------------===//
14 #ifndef CODEGEN_ASMPRINTER_DWARFDEBUG_H__
15 #define CODEGEN_ASMPRINTER_DWARFDEBUG_H__
17 #include "DwarfFile.h"
18 #include "AsmPrinterHandler.h"
20 #include "DebugLocEntry.h"
21 #include "DebugLocList.h"
22 #include "DwarfAccelTable.h"
23 #include "llvm/ADT/DenseMap.h"
24 #include "llvm/ADT/MapVector.h"
25 #include "llvm/ADT/SmallPtrSet.h"
26 #include "llvm/ADT/StringMap.h"
27 #include "llvm/ADT/FoldingSet.h"
28 #include "llvm/CodeGen/LexicalScopes.h"
29 #include "llvm/IR/DebugInfo.h"
30 #include "llvm/IR/DebugLoc.h"
31 #include "llvm/MC/MachineLocation.h"
32 #include "llvm/MC/MCDwarf.h"
33 #include "llvm/Support/Allocator.h"
43 class DwarfCompileUnit;
47 class MachineModuleInfo;
49 //===----------------------------------------------------------------------===//
50 /// \brief This class is used to record source line correspondence.
52 unsigned Line; // Source line number.
53 unsigned Column; // Source column.
54 unsigned SourceID; // Source ID number.
55 MCSymbol *Label; // Label in code ID number.
57 SrcLineInfo(unsigned L, unsigned C, unsigned S, MCSymbol *label)
58 : Line(L), Column(C), SourceID(S), Label(label) {}
61 unsigned getLine() const { return Line; }
62 unsigned getColumn() const { return Column; }
63 unsigned getSourceID() const { return SourceID; }
64 MCSymbol *getLabel() const { return Label; }
67 //===----------------------------------------------------------------------===//
68 /// \brief This class is used to track local variable information.
70 DIVariable Var; // Variable Descriptor.
71 DIE *TheDIE; // Variable DIE.
72 unsigned DotDebugLocOffset; // Offset in DotDebugLocEntries.
73 DbgVariable *AbsVar; // Corresponding Abstract variable, if any.
74 const MachineInstr *MInsn; // DBG_VALUE instruction of the variable.
79 // AbsVar may be NULL.
80 DbgVariable(DIVariable V, DbgVariable *AV, DwarfDebug *DD)
81 : Var(V), TheDIE(0), DotDebugLocOffset(~0U), AbsVar(AV), MInsn(0),
82 FrameIndex(~0), DD(DD) {}
85 DIVariable getVariable() const { return Var; }
86 void setDIE(DIE &D) { TheDIE = &D; }
87 DIE *getDIE() const { return TheDIE; }
88 void setDotDebugLocOffset(unsigned O) { DotDebugLocOffset = O; }
89 unsigned getDotDebugLocOffset() const { return DotDebugLocOffset; }
90 StringRef getName() const { return Var.getName(); }
91 DbgVariable *getAbstractVariable() const { return AbsVar; }
92 const MachineInstr *getMInsn() const { return MInsn; }
93 void setMInsn(const MachineInstr *M) { MInsn = M; }
94 int getFrameIndex() const { return FrameIndex; }
95 void setFrameIndex(int FI) { FrameIndex = FI; }
96 // Translate tag to proper Dwarf tag.
97 dwarf::Tag getTag() const {
98 if (Var.getTag() == dwarf::DW_TAG_arg_variable)
99 return dwarf::DW_TAG_formal_parameter;
101 return dwarf::DW_TAG_variable;
103 /// \brief Return true if DbgVariable is artificial.
104 bool isArtificial() const {
105 if (Var.isArtificial())
107 if (getType().isArtificial())
112 bool isObjectPointer() const {
113 if (Var.isObjectPointer())
115 if (getType().isObjectPointer())
120 bool variableHasComplexAddress() const {
121 assert(Var.isVariable() && "Invalid complex DbgVariable!");
122 return Var.hasComplexAddress();
124 bool isBlockByrefVariable() const;
125 unsigned getNumAddrElements() const {
126 assert(Var.isVariable() && "Invalid complex DbgVariable!");
127 return Var.getNumAddrElements();
129 uint64_t getAddrElement(unsigned i) const { return Var.getAddrElement(i); }
130 DIType getType() const;
133 /// resolve - Look in the DwarfDebug map for the MDNode that
134 /// corresponds to the reference.
135 template <typename T> T resolve(DIRef<T> Ref) const;
139 /// \brief Helper used to pair up a symbol and its DWARF compile unit.
141 SymbolCU(DwarfCompileUnit *CU, const MCSymbol *Sym) : Sym(Sym), CU(CU) {}
143 DwarfCompileUnit *CU;
146 /// \brief Collects and handles dwarf debug information.
147 class DwarfDebug : public AsmPrinterHandler {
148 // Target of Dwarf emission.
151 // Collected machine module information.
152 MachineModuleInfo *MMI;
154 // All DIEValues are allocated through this allocator.
155 BumpPtrAllocator DIEValueAllocator;
157 // Handle to the compile unit used for the inline extension handling,
158 // this is just so that the DIEValue allocator has a place to store
159 // the particular elements.
160 // FIXME: Store these off of DwarfDebug instead?
161 DwarfCompileUnit *FirstCU;
163 // Maps MDNode with its corresponding DwarfCompileUnit.
164 MapVector<const MDNode *, DwarfCompileUnit *> CUMap;
166 // Maps subprogram MDNode with its corresponding DwarfCompileUnit.
167 DenseMap<const MDNode *, DwarfCompileUnit *> SPMap;
169 // Maps a CU DIE with its corresponding DwarfCompileUnit.
170 DenseMap<const DIE *, DwarfCompileUnit *> CUDieMap;
172 /// Maps MDNodes for type system with the corresponding DIEs. These DIEs can
173 /// be shared across CUs, that is why we keep the map here instead
174 /// of in DwarfCompileUnit.
175 DenseMap<const MDNode *, DIE *> MDTypeNodeToDieMap;
177 // List of all labels used in aranges generation.
178 std::vector<SymbolCU> ArangeLabels;
180 // Size of each symbol emitted (for those symbols that have a specific size).
181 DenseMap<const MCSymbol *, uint64_t> SymSize;
183 // Provides a unique id per text section.
184 typedef DenseMap<const MCSection *, SmallVector<SymbolCU, 8> > SectionMapType;
185 SectionMapType SectionMap;
187 // List of arguments for current function.
188 SmallVector<DbgVariable *, 8> CurrentFnArguments;
190 LexicalScopes LScopes;
192 // Collection of abstract subprogram DIEs.
193 DenseMap<const MDNode *, DIE *> AbstractSPDies;
195 // Collection of dbg variables of a scope.
196 typedef DenseMap<LexicalScope *, SmallVector<DbgVariable *, 8> >
198 ScopeVariablesMap ScopeVariables;
200 // Collection of abstract variables.
201 DenseMap<const MDNode *, DbgVariable *> AbstractVariables;
203 // Collection of DebugLocEntry. Stored in a linked list so that DIELocLists
204 // can refer to them in spite of insertions into this list.
205 SmallVector<DebugLocList, 4> DotDebugLocEntries;
207 // Collection of subprogram DIEs that are marked (at the end of the module)
209 SmallPtrSet<DIE *, 4> InlinedSubprogramDIEs;
211 // This is a collection of subprogram MDNodes that are processed to
213 SmallPtrSet<const MDNode *, 16> ProcessedSPNodes;
215 // Maps instruction with label emitted before instruction.
216 DenseMap<const MachineInstr *, MCSymbol *> LabelsBeforeInsn;
218 // Maps instruction with label emitted after instruction.
219 DenseMap<const MachineInstr *, MCSymbol *> LabelsAfterInsn;
221 // Every user variable mentioned by a DBG_VALUE instruction in order of
223 SmallVector<const MDNode *, 8> UserVariables;
225 // For each user variable, keep a list of DBG_VALUE instructions in order.
226 // The list can also contain normal instructions that clobber the previous
228 typedef DenseMap<const MDNode *, SmallVector<const MachineInstr *, 4> >
230 DbgValueHistoryMap DbgValues;
232 // Previous instruction's location information. This is used to determine
233 // label location to indicate scope boundries in dwarf debug info.
234 DebugLoc PrevInstLoc;
237 // This location indicates end of function prologue and beginning of function
239 DebugLoc PrologEndLoc;
241 // If nonnull, stores the current machine function we're processing.
242 const MachineFunction *CurFn;
244 // If nonnull, stores the current machine instruction we're processing.
245 const MachineInstr *CurMI;
247 // If nonnull, stores the section that the previous function was allocated to
249 const MCSection *PrevSection;
251 // If nonnull, stores the CU in which the previous subprogram was contained.
252 const DwarfCompileUnit *PrevCU;
254 // Section Symbols: these are assembler temporary labels that are emitted at
255 // the beginning of each supported dwarf section. These are used to form
256 // section offsets and are created by EmitSectionLabels.
257 MCSymbol *DwarfInfoSectionSym, *DwarfAbbrevSectionSym;
258 MCSymbol *DwarfStrSectionSym, *TextSectionSym, *DwarfDebugRangeSectionSym;
259 MCSymbol *DwarfDebugLocSectionSym, *DwarfLineSectionSym, *DwarfAddrSectionSym;
260 MCSymbol *FunctionBeginSym, *FunctionEndSym;
261 MCSymbol *DwarfInfoDWOSectionSym, *DwarfAbbrevDWOSectionSym;
262 MCSymbol *DwarfStrDWOSectionSym;
263 MCSymbol *DwarfGnuPubNamesSectionSym, *DwarfGnuPubTypesSectionSym;
265 // As an optimization, there is no need to emit an entry in the directory
266 // table for the same directory as DW_AT_comp_dir.
267 StringRef CompilationDir;
269 // Counter for assigning globally unique IDs for ranges.
270 unsigned GlobalRangeCount;
272 // Holder for the file specific debug information.
273 DwarfFile InfoHolder;
275 // Holders for the various debug information flags that we might need to
276 // have exposed. See accessor functions below for description.
278 // Holder for imported entities.
279 typedef SmallVector<std::pair<const MDNode *, const MDNode *>, 32>
281 ImportedEntityMap ScopesWithImportedEntities;
283 // Map from MDNodes for user-defined types to the type units that describe
285 DenseMap<const MDNode *, const DwarfTypeUnit *> DwarfTypeUnits;
287 // Whether to emit the pubnames/pubtypes sections.
288 bool HasDwarfPubSections;
290 // Whether or not to use AT_ranges for compilation units.
293 // Whether we emitted a function into a section other than the default
295 bool UsedNonDefaultText;
297 // Version of dwarf we're emitting.
298 unsigned DwarfVersion;
300 // Maps from a type identifier to the actual MDNode.
301 DITypeIdentifierMap TypeIdentifierMap;
303 // DWARF5 Experimental Options
304 bool HasDwarfAccelTables;
307 // Separated Dwarf Variables
308 // In general these will all be for bits that are left in the
309 // original object file, rather than things that are meant
310 // to be in the .dwo sections.
312 // Holder for the skeleton information.
313 DwarfFile SkeletonHolder;
315 /// Store file names for type units under fission in a line table header that
316 /// will be emitted into debug_line.dwo.
317 // FIXME: replace this with a map from comp_dir to table so that we can emit
318 // multiple tables during LTO each of which uses directory 0, referencing the
319 // comp_dir of all the type units that use it.
320 MCDwarfDwoLineTable SplitTypeUnitFileTable;
322 // True iff there are multiple CUs in this module.
325 AddressPool AddrPool;
327 DwarfAccelTable AccelNames;
328 DwarfAccelTable AccelObjC;
329 DwarfAccelTable AccelNamespace;
330 DwarfAccelTable AccelTypes;
332 MCDwarfDwoLineTable *getDwoLineTable(const DwarfCompileUnit &);
334 void addScopeVariable(LexicalScope *LS, DbgVariable *Var);
336 const SmallVectorImpl<std::unique_ptr<DwarfUnit>> &getUnits() {
337 return InfoHolder.getUnits();
340 /// \brief Find abstract variable associated with Var.
341 DbgVariable *findAbstractVariable(DIVariable &Var, DebugLoc Loc);
343 /// \brief Find DIE for the given subprogram and attach appropriate
344 /// DW_AT_low_pc and DW_AT_high_pc attributes. If there are global
345 /// variables in this scope then create and insert DIEs for these
347 DIE *updateSubprogramScopeDIE(DwarfCompileUnit &SPCU, DISubprogram SP);
349 /// \brief A helper function to check whether the DIE for a given Scope is
350 /// going to be null.
351 bool isLexicalScopeDIENull(LexicalScope *Scope);
353 /// \brief A helper function to construct a RangeSpanList for a given
355 void addScopeRangeList(DwarfCompileUnit &TheCU, DIE &ScopeDIE,
356 const SmallVectorImpl<InsnRange> &Range);
358 /// \brief Construct new DW_TAG_lexical_block for this scope and
359 /// attach DW_AT_low_pc/DW_AT_high_pc labels.
360 DIE *constructLexicalScopeDIE(DwarfCompileUnit &TheCU, LexicalScope *Scope);
362 /// \brief This scope represents inlined body of a function. Construct
363 /// DIE to represent this concrete inlined copy of the function.
364 DIE *constructInlinedScopeDIE(DwarfCompileUnit &TheCU, LexicalScope *Scope);
366 /// \brief Construct a DIE for this scope.
367 DIE *constructScopeDIE(DwarfCompileUnit &TheCU, LexicalScope *Scope);
368 /// A helper function to create children of a Scope DIE.
369 DIE *createScopeChildrenDIE(DwarfCompileUnit &TheCU, LexicalScope *Scope,
370 SmallVectorImpl<DIE *> &Children);
372 /// \brief Emit initial Dwarf sections with a label at the start of each one.
373 void emitSectionLabels();
375 /// \brief Compute the size and offset of a DIE given an incoming Offset.
376 unsigned computeSizeAndOffset(DIE *Die, unsigned Offset);
378 /// \brief Compute the size and offset of all the DIEs.
379 void computeSizeAndOffsets();
381 /// \brief Attach DW_AT_inline attribute with inlined subprogram DIEs.
382 void computeInlinedDIEs();
384 /// \brief Collect info for variables that were optimized out.
385 void collectDeadVariables();
387 /// \brief Finish off debug information after all functions have been
389 void finalizeModuleInfo();
391 /// \brief Emit labels to close any remaining sections that have been left
395 /// \brief Emit the debug info section.
396 void emitDebugInfo();
398 /// \brief Emit the abbreviation section.
399 void emitAbbreviations();
401 /// \brief Emit the last address of the section and the end of
403 void emitEndOfLineMatrix(unsigned SectionEnd);
405 /// \brief Emit visible names into a hashed accelerator table section.
406 void emitAccelNames();
408 /// \brief Emit objective C classes and categories into a hashed
409 /// accelerator table section.
410 void emitAccelObjC();
412 /// \brief Emit namespace dies into a hashed accelerator table.
413 void emitAccelNamespaces();
415 /// \brief Emit type dies into a hashed accelerator table.
416 void emitAccelTypes();
418 /// \brief Emit visible names into a debug pubnames section.
419 /// \param GnuStyle determines whether or not we want to emit
420 /// additional information into the table ala newer gcc for gdb
422 void emitDebugPubNames(bool GnuStyle = false);
424 /// \brief Emit visible types into a debug pubtypes section.
425 /// \param GnuStyle determines whether or not we want to emit
426 /// additional information into the table ala newer gcc for gdb
428 void emitDebugPubTypes(bool GnuStyle = false);
431 emitDebugPubSection(bool GnuStyle, const MCSection *PSec, StringRef Name,
432 const StringMap<const DIE *> &(DwarfUnit::*Accessor)()
435 /// \brief Emit visible names into a debug str section.
438 /// \brief Emit visible names into a debug loc section.
441 /// \brief Emit visible names into a debug loc dwo section.
442 void emitDebugLocDWO();
444 /// \brief Emit visible names into a debug aranges section.
445 void emitDebugARanges();
447 /// \brief Emit visible names into a debug ranges section.
448 void emitDebugRanges();
450 /// \brief Emit inline info using custom format.
451 void emitDebugInlineInfo();
453 /// DWARF 5 Experimental Split Dwarf Emitters
455 /// \brief Initialize common features of skeleton units.
456 void initSkeletonUnit(const DwarfUnit &U, DIE &Die,
457 std::unique_ptr<DwarfUnit> NewU);
459 /// \brief Construct the split debug info compile unit for the debug info
461 DwarfCompileUnit &constructSkeletonCU(const DwarfCompileUnit &CU);
463 /// \brief Construct the split debug info compile unit for the debug info
465 DwarfTypeUnit &constructSkeletonTU(DwarfTypeUnit &TU);
467 /// \brief Emit the debug info dwo section.
468 void emitDebugInfoDWO();
470 /// \brief Emit the debug abbrev dwo section.
471 void emitDebugAbbrevDWO();
473 /// \brief Emit the debug line dwo section.
474 void emitDebugLineDWO();
476 /// \brief Emit the debug str dwo section.
477 void emitDebugStrDWO();
479 /// Flags to let the linker know we have emitted new style pubnames. Only
480 /// emit it here if we don't have a skeleton CU for split dwarf.
481 void addGnuPubAttributes(DwarfUnit &U, DIE &D) const;
483 /// \brief Create new DwarfCompileUnit for the given metadata node with tag
484 /// DW_TAG_compile_unit.
485 DwarfCompileUnit &constructDwarfCompileUnit(DICompileUnit DIUnit);
487 /// \brief Construct subprogram DIE.
488 void constructSubprogramDIE(DwarfCompileUnit &TheCU, const MDNode *N);
490 /// \brief Construct imported_module or imported_declaration DIE.
491 void constructImportedEntityDIE(DwarfCompileUnit &TheCU, const MDNode *N);
493 /// \brief Construct import_module DIE.
494 void constructImportedEntityDIE(DwarfCompileUnit &TheCU, const MDNode *N,
497 /// \brief Construct import_module DIE.
498 void constructImportedEntityDIE(DwarfCompileUnit &TheCU,
499 const DIImportedEntity &Module, DIE *Context);
501 /// \brief Register a source line with debug info. Returns the unique
502 /// label that was emitted and which provides correspondence to the
503 /// source line list.
504 void recordSourceLine(unsigned Line, unsigned Col, const MDNode *Scope,
507 /// \brief Indentify instructions that are marking the beginning of or
508 /// ending of a scope.
509 void identifyScopeMarkers();
511 /// \brief If Var is an current function argument that add it in
512 /// CurrentFnArguments list.
513 bool addCurrentFnArgument(DbgVariable *Var, LexicalScope *Scope);
515 /// \brief Populate LexicalScope entries with variables' info.
516 void collectVariableInfo(SmallPtrSet<const MDNode *, 16> &ProcessedVars);
518 /// \brief Collect variable information from the side table maintained
520 void collectVariableInfoFromMMITable(SmallPtrSet<const MDNode *, 16> &P);
522 /// \brief Ensure that a label will be emitted before MI.
523 void requestLabelBeforeInsn(const MachineInstr *MI) {
524 LabelsBeforeInsn.insert(std::make_pair(MI, (MCSymbol *)0));
527 /// \brief Return Label preceding the instruction.
528 MCSymbol *getLabelBeforeInsn(const MachineInstr *MI);
530 /// \brief Ensure that a label will be emitted after MI.
531 void requestLabelAfterInsn(const MachineInstr *MI) {
532 LabelsAfterInsn.insert(std::make_pair(MI, (MCSymbol *)0));
535 /// \brief Return Label immediately following the instruction.
536 MCSymbol *getLabelAfterInsn(const MachineInstr *MI);
538 void attachLowHighPC(DwarfCompileUnit &Unit, DIE &D, MCSymbol *Begin,
542 //===--------------------------------------------------------------------===//
543 // Main entry points.
545 DwarfDebug(AsmPrinter *A, Module *M);
547 void insertDIE(const MDNode *TypeMD, DIE *Die) {
548 MDTypeNodeToDieMap.insert(std::make_pair(TypeMD, Die));
550 DIE *getDIE(const MDNode *TypeMD) {
551 return MDTypeNodeToDieMap.lookup(TypeMD);
554 /// \brief Emit all Dwarf sections that should come prior to the
558 /// \brief Emit all Dwarf sections that should come after the content.
559 void endModule() override;
561 /// \brief Gather pre-function debug information.
562 void beginFunction(const MachineFunction *MF) override;
564 /// \brief Gather and emit post-function debug information.
565 void endFunction(const MachineFunction *MF) override;
567 /// \brief Process beginning of an instruction.
568 void beginInstruction(const MachineInstr *MI) override;
570 /// \brief Process end of an instruction.
571 void endInstruction() override;
573 /// \brief Add a DIE to the set of types that we're going to pull into
575 void addDwarfTypeUnitType(DwarfCompileUnit &CU, StringRef Identifier,
576 DIE &Die, DICompositeType CTy);
578 /// \brief Add a label so that arange data can be generated for it.
579 void addArangeLabel(SymbolCU SCU) { ArangeLabels.push_back(SCU); }
581 /// \brief For symbols that have a size designated (e.g. common symbols),
582 /// this tracks that size.
583 void setSymbolSize(const MCSymbol *Sym, uint64_t Size) override {
587 /// \brief Recursively Emits a debug information entry.
588 void emitDIE(DIE &Die);
590 // Experimental DWARF5 features.
592 /// \brief Returns whether or not to emit tables that dwarf consumers can
593 /// use to accelerate lookup.
594 bool useDwarfAccelTables() const { return HasDwarfAccelTables; }
596 /// \brief Returns whether or not to change the current debug info for the
597 /// split dwarf proposal support.
598 bool useSplitDwarf() const { return HasSplitDwarf; }
600 /// Returns the Dwarf Version.
601 unsigned getDwarfVersion() const { return DwarfVersion; }
603 /// Returns the section symbol for the .debug_loc section.
604 MCSymbol *getDebugLocSym() const { return DwarfDebugLocSectionSym; }
606 /// Returns the previous section that was emitted into.
607 const MCSection *getPrevSection() const { return PrevSection; }
609 /// Returns the previous CU that was being updated
610 const DwarfCompileUnit *getPrevCU() const { return PrevCU; }
612 /// Returns the entries for the .debug_loc section.
613 const SmallVectorImpl<DebugLocList> &
614 getDebugLocEntries() const {
615 return DotDebugLocEntries;
618 /// \brief Emit an entry for the debug loc section. This can be used to
619 /// handle an entry that's going to be emitted into the debug loc section.
620 void emitDebugLocEntry(ByteStreamer &Streamer, const DebugLocEntry &Entry);
622 /// Emit the location for a debug loc entry, including the size header.
623 void emitDebugLocEntryLocation(const DebugLocEntry &Entry);
625 /// Find the MDNode for the given reference.
626 template <typename T> T resolve(DIRef<T> Ref) const {
627 return Ref.resolve(TypeIdentifierMap);
630 /// \brief Return the TypeIdentifierMap.
631 const DITypeIdentifierMap &getTypeIdentifierMap() const {
632 return TypeIdentifierMap;
635 /// Find the DwarfCompileUnit for the given CU Die.
636 DwarfCompileUnit *lookupUnit(const DIE *CU) const {
637 return CUDieMap.lookup(CU);
639 /// isSubprogramContext - Return true if Context is either a subprogram
640 /// or another context nested inside a subprogram.
641 bool isSubprogramContext(const MDNode *Context);
643 void addSubprogramNames(DISubprogram SP, DIE &Die);
645 AddressPool &getAddressPool() { return AddrPool; }
647 void addAccelName(StringRef Name, const DIE &Die);
649 void addAccelObjC(StringRef Name, const DIE &Die);
651 void addAccelNamespace(StringRef Name, const DIE &Die);
653 void addAccelType(StringRef Name, const DIE &Die, char Flags);
655 } // End of namespace llvm