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 "DbgValueHistoryCalculator.h"
21 #include "DebugLocEntry.h"
22 #include "DebugLocList.h"
23 #include "DwarfAccelTable.h"
24 #include "llvm/ADT/DenseMap.h"
25 #include "llvm/ADT/MapVector.h"
26 #include "llvm/ADT/SmallPtrSet.h"
27 #include "llvm/ADT/StringMap.h"
28 #include "llvm/ADT/FoldingSet.h"
29 #include "llvm/CodeGen/LexicalScopes.h"
30 #include "llvm/IR/DebugInfo.h"
31 #include "llvm/IR/DebugLoc.h"
32 #include "llvm/MC/MachineLocation.h"
33 #include "llvm/MC/MCDwarf.h"
34 #include "llvm/Support/Allocator.h"
44 class DwarfCompileUnit;
48 class MachineModuleInfo;
50 //===----------------------------------------------------------------------===//
51 /// \brief This class is used to record source line correspondence.
53 unsigned Line; // Source line number.
54 unsigned Column; // Source column.
55 unsigned SourceID; // Source ID number.
56 MCSymbol *Label; // Label in code ID number.
58 SrcLineInfo(unsigned L, unsigned C, unsigned S, MCSymbol *label)
59 : Line(L), Column(C), SourceID(S), Label(label) {}
62 unsigned getLine() const { return Line; }
63 unsigned getColumn() const { return Column; }
64 unsigned getSourceID() const { return SourceID; }
65 MCSymbol *getLabel() const { return Label; }
68 //===----------------------------------------------------------------------===//
69 /// \brief This class is used to track local variable information.
71 DIVariable Var; // Variable Descriptor.
72 DIE *TheDIE; // Variable DIE.
73 unsigned DotDebugLocOffset; // Offset in DotDebugLocEntries.
74 DbgVariable *AbsVar; // Corresponding Abstract variable, if any.
75 const MachineInstr *MInsn; // DBG_VALUE instruction of the variable.
80 // AbsVar may be NULL.
81 DbgVariable(DIVariable V, DbgVariable *AV, DwarfDebug *DD)
82 : Var(V), TheDIE(nullptr), DotDebugLocOffset(~0U), AbsVar(AV),
83 MInsn(nullptr), FrameIndex(~0), DD(DD) {}
86 DIVariable getVariable() const { return Var; }
87 void setDIE(DIE &D) { TheDIE = &D; }
88 DIE *getDIE() const { return TheDIE; }
89 void setDotDebugLocOffset(unsigned O) { DotDebugLocOffset = O; }
90 unsigned getDotDebugLocOffset() const { return DotDebugLocOffset; }
91 StringRef getName() const { return Var.getName(); }
92 DbgVariable *getAbstractVariable() const { return AbsVar; }
93 const MachineInstr *getMInsn() const { return MInsn; }
94 void setMInsn(const MachineInstr *M) { MInsn = M; }
95 int getFrameIndex() const { return FrameIndex; }
96 void setFrameIndex(int FI) { FrameIndex = FI; }
97 // Translate tag to proper Dwarf tag.
98 dwarf::Tag getTag() const {
99 if (Var.getTag() == dwarf::DW_TAG_arg_variable)
100 return dwarf::DW_TAG_formal_parameter;
102 return dwarf::DW_TAG_variable;
104 /// \brief Return true if DbgVariable is artificial.
105 bool isArtificial() const {
106 if (Var.isArtificial())
108 if (getType().isArtificial())
113 bool isObjectPointer() const {
114 if (Var.isObjectPointer())
116 if (getType().isObjectPointer())
121 bool variableHasComplexAddress() const {
122 assert(Var.isVariable() && "Invalid complex DbgVariable!");
123 return Var.hasComplexAddress();
125 bool isBlockByrefVariable() const;
126 unsigned getNumAddrElements() const {
127 assert(Var.isVariable() && "Invalid complex DbgVariable!");
128 return Var.getNumAddrElements();
130 uint64_t getAddrElement(unsigned i) const { return Var.getAddrElement(i); }
131 DIType getType() const;
134 /// resolve - Look in the DwarfDebug map for the MDNode that
135 /// corresponds to the reference.
136 template <typename T> T resolve(DIRef<T> Ref) const;
140 /// \brief Helper used to pair up a symbol and its DWARF compile unit.
142 SymbolCU(DwarfCompileUnit *CU, const MCSymbol *Sym) : Sym(Sym), CU(CU) {}
144 DwarfCompileUnit *CU;
147 /// \brief Collects and handles dwarf debug information.
148 class DwarfDebug : public AsmPrinterHandler {
149 // Target of Dwarf emission.
152 // Collected machine module information.
153 MachineModuleInfo *MMI;
155 // All DIEValues are allocated through this allocator.
156 BumpPtrAllocator DIEValueAllocator;
158 // Handle to the compile unit used for the inline extension handling,
159 // this is just so that the DIEValue allocator has a place to store
160 // the particular elements.
161 // FIXME: Store these off of DwarfDebug instead?
162 DwarfCompileUnit *FirstCU;
164 // Maps MDNode with its corresponding DwarfCompileUnit.
165 MapVector<const MDNode *, DwarfCompileUnit *> CUMap;
167 // Maps subprogram MDNode with its corresponding DwarfCompileUnit.
168 DenseMap<const MDNode *, DwarfCompileUnit *> SPMap;
170 // Maps a CU DIE with its corresponding DwarfCompileUnit.
171 DenseMap<const DIE *, DwarfCompileUnit *> CUDieMap;
173 /// Maps MDNodes for type system with the corresponding DIEs. These DIEs can
174 /// be shared across CUs, that is why we keep the map here instead
175 /// of in DwarfCompileUnit.
176 DenseMap<const MDNode *, DIE *> MDTypeNodeToDieMap;
178 // List of all labels used in aranges generation.
179 std::vector<SymbolCU> ArangeLabels;
181 // Size of each symbol emitted (for those symbols that have a specific size).
182 DenseMap<const MCSymbol *, uint64_t> SymSize;
184 // Provides a unique id per text section.
185 typedef DenseMap<const MCSection *, SmallVector<SymbolCU, 8> > SectionMapType;
186 SectionMapType SectionMap;
188 // List of arguments for current function.
189 SmallVector<DbgVariable *, 8> CurrentFnArguments;
191 LexicalScopes LScopes;
193 // Collection of abstract subprogram DIEs.
194 DenseMap<const MDNode *, DIE *> AbstractSPDies;
196 // Collection of dbg variables of a scope.
197 typedef DenseMap<LexicalScope *, SmallVector<DbgVariable *, 8> >
199 ScopeVariablesMap ScopeVariables;
201 // Collection of abstract variables.
202 DenseMap<const MDNode *, DbgVariable *> AbstractVariables;
204 // Collection of DebugLocEntry. Stored in a linked list so that DIELocLists
205 // can refer to them in spite of insertions into this list.
206 SmallVector<DebugLocList, 4> DotDebugLocEntries;
208 // Collection of subprogram DIEs that are marked (at the end of the module)
210 SmallPtrSet<DIE *, 4> InlinedSubprogramDIEs;
212 // This is a collection of subprogram MDNodes that are processed to
214 SmallPtrSet<const MDNode *, 16> ProcessedSPNodes;
216 // Maps instruction with label emitted before instruction.
217 DenseMap<const MachineInstr *, MCSymbol *> LabelsBeforeInsn;
219 // Maps instruction with label emitted after instruction.
220 DenseMap<const MachineInstr *, MCSymbol *> LabelsAfterInsn;
222 // History of DBG_VALUE and clobber instructions for each user variable.
223 // Variables are listed in order of appearance.
224 DbgValueHistoryMap DbgValues;
226 // Previous instruction's location information. This is used to determine
227 // label location to indicate scope boundries in dwarf debug info.
228 DebugLoc PrevInstLoc;
231 // This location indicates end of function prologue and beginning of function
233 DebugLoc PrologEndLoc;
235 // If nonnull, stores the current machine function we're processing.
236 const MachineFunction *CurFn;
238 // If nonnull, stores the current machine instruction we're processing.
239 const MachineInstr *CurMI;
241 // If nonnull, stores the section that the previous function was allocated to
243 const MCSection *PrevSection;
245 // If nonnull, stores the CU in which the previous subprogram was contained.
246 const DwarfCompileUnit *PrevCU;
248 // Section Symbols: these are assembler temporary labels that are emitted at
249 // the beginning of each supported dwarf section. These are used to form
250 // section offsets and are created by EmitSectionLabels.
251 MCSymbol *DwarfInfoSectionSym, *DwarfAbbrevSectionSym;
252 MCSymbol *DwarfStrSectionSym, *TextSectionSym, *DwarfDebugRangeSectionSym;
253 MCSymbol *DwarfDebugLocSectionSym, *DwarfLineSectionSym, *DwarfAddrSectionSym;
254 MCSymbol *FunctionBeginSym, *FunctionEndSym;
255 MCSymbol *DwarfInfoDWOSectionSym, *DwarfAbbrevDWOSectionSym;
256 MCSymbol *DwarfStrDWOSectionSym;
257 MCSymbol *DwarfGnuPubNamesSectionSym, *DwarfGnuPubTypesSectionSym;
259 // As an optimization, there is no need to emit an entry in the directory
260 // table for the same directory as DW_AT_comp_dir.
261 StringRef CompilationDir;
263 // Counter for assigning globally unique IDs for ranges.
264 unsigned GlobalRangeCount;
266 // Holder for the file specific debug information.
267 DwarfFile InfoHolder;
269 // Holders for the various debug information flags that we might need to
270 // have exposed. See accessor functions below for description.
272 // Holder for imported entities.
273 typedef SmallVector<std::pair<const MDNode *, const MDNode *>, 32>
275 ImportedEntityMap ScopesWithImportedEntities;
277 // Map from MDNodes for user-defined types to the type units that describe
279 DenseMap<const MDNode *, const DwarfTypeUnit *> DwarfTypeUnits;
281 SmallVector<std::pair<std::unique_ptr<DwarfTypeUnit>, DICompositeType>, 1> TypeUnitsUnderConstruction;
283 // Whether to emit the pubnames/pubtypes sections.
284 bool HasDwarfPubSections;
286 // Whether or not to use AT_ranges for compilation units.
289 // Whether we emitted a function into a section other than the default
291 bool UsedNonDefaultText;
293 // Version of dwarf we're emitting.
294 unsigned DwarfVersion;
296 // Maps from a type identifier to the actual MDNode.
297 DITypeIdentifierMap TypeIdentifierMap;
299 // DWARF5 Experimental Options
300 bool HasDwarfAccelTables;
303 // Separated Dwarf Variables
304 // In general these will all be for bits that are left in the
305 // original object file, rather than things that are meant
306 // to be in the .dwo sections.
308 // Holder for the skeleton information.
309 DwarfFile SkeletonHolder;
311 /// Store file names for type units under fission in a line table header that
312 /// will be emitted into debug_line.dwo.
313 // FIXME: replace this with a map from comp_dir to table so that we can emit
314 // multiple tables during LTO each of which uses directory 0, referencing the
315 // comp_dir of all the type units that use it.
316 MCDwarfDwoLineTable SplitTypeUnitFileTable;
318 // True iff there are multiple CUs in this module.
321 AddressPool AddrPool;
323 DwarfAccelTable AccelNames;
324 DwarfAccelTable AccelObjC;
325 DwarfAccelTable AccelNamespace;
326 DwarfAccelTable AccelTypes;
328 MCDwarfDwoLineTable *getDwoLineTable(const DwarfCompileUnit &);
330 void addScopeVariable(LexicalScope *LS, DbgVariable *Var);
332 const SmallVectorImpl<std::unique_ptr<DwarfUnit>> &getUnits() {
333 return InfoHolder.getUnits();
336 /// \brief Find abstract variable associated with Var.
337 DbgVariable *findAbstractVariable(DIVariable &Var, DebugLoc Loc);
339 /// \brief Find DIE for the given subprogram and attach appropriate
340 /// DW_AT_low_pc and DW_AT_high_pc attributes. If there are global
341 /// variables in this scope then create and insert DIEs for these
343 DIE &updateSubprogramScopeDIE(DwarfCompileUnit &SPCU, DISubprogram SP);
345 /// \brief A helper function to check whether the DIE for a given Scope is
346 /// going to be null.
347 bool isLexicalScopeDIENull(LexicalScope *Scope);
349 /// \brief A helper function to construct a RangeSpanList for a given
351 void addScopeRangeList(DwarfCompileUnit &TheCU, DIE &ScopeDIE,
352 const SmallVectorImpl<InsnRange> &Range);
354 /// \brief Construct new DW_TAG_lexical_block for this scope and
355 /// attach DW_AT_low_pc/DW_AT_high_pc labels.
356 std::unique_ptr<DIE> constructLexicalScopeDIE(DwarfCompileUnit &TheCU,
357 LexicalScope *Scope);
359 /// \brief This scope represents inlined body of a function. Construct
360 /// DIE to represent this concrete inlined copy of the function.
361 std::unique_ptr<DIE> constructInlinedScopeDIE(DwarfCompileUnit &TheCU,
362 LexicalScope *Scope);
364 /// \brief Construct a DIE for this scope.
365 std::unique_ptr<DIE> constructScopeDIE(DwarfCompileUnit &TheCU,
366 LexicalScope *Scope);
367 void createAndAddScopeChildren(DwarfCompileUnit &TheCU, LexicalScope *Scope,
369 /// \brief Construct a DIE for this abstract scope.
370 void constructAbstractSubprogramScopeDIE(DwarfCompileUnit &TheCU,
371 LexicalScope *Scope);
372 /// \brief Construct a DIE for this subprogram scope.
373 DIE &constructSubprogramScopeDIE(DwarfCompileUnit &TheCU,
374 LexicalScope *Scope);
375 /// A helper function to create children of a Scope DIE.
376 DIE *createScopeChildrenDIE(DwarfCompileUnit &TheCU, LexicalScope *Scope,
377 SmallVectorImpl<std::unique_ptr<DIE>> &Children);
379 /// \brief Emit initial Dwarf sections with a label at the start of each one.
380 void emitSectionLabels();
382 /// \brief Compute the size and offset of a DIE given an incoming Offset.
383 unsigned computeSizeAndOffset(DIE *Die, unsigned Offset);
385 /// \brief Compute the size and offset of all the DIEs.
386 void computeSizeAndOffsets();
388 /// \brief Collect info for variables that were optimized out.
389 void collectDeadVariables();
391 /// \brief Finish off debug information after all functions have been
393 void finalizeModuleInfo();
395 /// \brief Emit labels to close any remaining sections that have been left
399 /// \brief Emit the debug info section.
400 void emitDebugInfo();
402 /// \brief Emit the abbreviation section.
403 void emitAbbreviations();
405 /// \brief Emit the last address of the section and the end of
407 void emitEndOfLineMatrix(unsigned SectionEnd);
409 /// \brief Emit visible names into a hashed accelerator table section.
410 void emitAccelNames();
412 /// \brief Emit objective C classes and categories into a hashed
413 /// accelerator table section.
414 void emitAccelObjC();
416 /// \brief Emit namespace dies into a hashed accelerator table.
417 void emitAccelNamespaces();
419 /// \brief Emit type dies into a hashed accelerator table.
420 void emitAccelTypes();
422 /// \brief Emit visible names into a debug pubnames section.
423 /// \param GnuStyle determines whether or not we want to emit
424 /// additional information into the table ala newer gcc for gdb
426 void emitDebugPubNames(bool GnuStyle = false);
428 /// \brief Emit visible types into a debug pubtypes section.
429 /// \param GnuStyle determines whether or not we want to emit
430 /// additional information into the table ala newer gcc for gdb
432 void emitDebugPubTypes(bool GnuStyle = false);
435 emitDebugPubSection(bool GnuStyle, const MCSection *PSec, StringRef Name,
436 const StringMap<const DIE *> &(DwarfUnit::*Accessor)()
439 /// \brief Emit visible names into a debug str section.
442 /// \brief Emit visible names into a debug loc section.
445 /// \brief Emit visible names into a debug loc dwo section.
446 void emitDebugLocDWO();
448 /// \brief Emit visible names into a debug aranges section.
449 void emitDebugARanges();
451 /// \brief Emit visible names into a debug ranges section.
452 void emitDebugRanges();
454 /// \brief Emit inline info using custom format.
455 void emitDebugInlineInfo();
457 /// DWARF 5 Experimental Split Dwarf Emitters
459 /// \brief Initialize common features of skeleton units.
460 void initSkeletonUnit(const DwarfUnit &U, DIE &Die,
461 std::unique_ptr<DwarfUnit> NewU);
463 /// \brief Construct the split debug info compile unit for the debug info
465 DwarfCompileUnit &constructSkeletonCU(const DwarfCompileUnit &CU);
467 /// \brief Construct the split debug info compile unit for the debug info
469 DwarfTypeUnit &constructSkeletonTU(DwarfTypeUnit &TU);
471 /// \brief Emit the debug info dwo section.
472 void emitDebugInfoDWO();
474 /// \brief Emit the debug abbrev dwo section.
475 void emitDebugAbbrevDWO();
477 /// \brief Emit the debug line dwo section.
478 void emitDebugLineDWO();
480 /// \brief Emit the debug str dwo section.
481 void emitDebugStrDWO();
483 /// Flags to let the linker know we have emitted new style pubnames. Only
484 /// emit it here if we don't have a skeleton CU for split dwarf.
485 void addGnuPubAttributes(DwarfUnit &U, DIE &D) const;
487 /// \brief Create new DwarfCompileUnit for the given metadata node with tag
488 /// DW_TAG_compile_unit.
489 DwarfCompileUnit &constructDwarfCompileUnit(DICompileUnit DIUnit);
491 /// \brief Construct subprogram DIE.
492 void constructSubprogramDIE(DwarfCompileUnit &TheCU, const MDNode *N);
494 /// \brief Construct imported_module or imported_declaration DIE.
495 void constructImportedEntityDIE(DwarfCompileUnit &TheCU, const MDNode *N);
497 /// \brief Construct import_module DIE.
498 void constructImportedEntityDIE(DwarfCompileUnit &TheCU, const MDNode *N,
501 /// \brief Construct import_module DIE.
502 void constructImportedEntityDIE(DwarfCompileUnit &TheCU,
503 const DIImportedEntity &Module, DIE &Context);
505 /// \brief Register a source line with debug info. Returns the unique
506 /// label that was emitted and which provides correspondence to the
507 /// source line list.
508 void recordSourceLine(unsigned Line, unsigned Col, const MDNode *Scope,
511 /// \brief Indentify instructions that are marking the beginning of or
512 /// ending of a scope.
513 void identifyScopeMarkers();
515 /// \brief If Var is an current function argument that add it in
516 /// CurrentFnArguments list.
517 bool addCurrentFnArgument(DbgVariable *Var, LexicalScope *Scope);
519 /// \brief Populate LexicalScope entries with variables' info.
520 void collectVariableInfo(SmallPtrSet<const MDNode *, 16> &ProcessedVars);
522 /// \brief Collect variable information from the side table maintained
524 void collectVariableInfoFromMMITable(SmallPtrSet<const MDNode *, 16> &P);
526 /// \brief Ensure that a label will be emitted before MI.
527 void requestLabelBeforeInsn(const MachineInstr *MI) {
528 LabelsBeforeInsn.insert(std::make_pair(MI, nullptr));
531 /// \brief Return Label preceding the instruction.
532 MCSymbol *getLabelBeforeInsn(const MachineInstr *MI);
534 /// \brief Ensure that a label will be emitted after MI.
535 void requestLabelAfterInsn(const MachineInstr *MI) {
536 LabelsAfterInsn.insert(std::make_pair(MI, nullptr));
539 /// \brief Return Label immediately following the instruction.
540 MCSymbol *getLabelAfterInsn(const MachineInstr *MI);
542 void attachLowHighPC(DwarfCompileUnit &Unit, DIE &D, MCSymbol *Begin,
546 //===--------------------------------------------------------------------===//
547 // Main entry points.
549 DwarfDebug(AsmPrinter *A, Module *M);
551 ~DwarfDebug() override;
553 void insertDIE(const MDNode *TypeMD, DIE *Die) {
554 MDTypeNodeToDieMap.insert(std::make_pair(TypeMD, Die));
556 DIE *getDIE(const MDNode *TypeMD) {
557 return MDTypeNodeToDieMap.lookup(TypeMD);
560 /// \brief Emit all Dwarf sections that should come prior to the
564 /// \brief Emit all Dwarf sections that should come after the content.
565 void endModule() override;
567 /// \brief Gather pre-function debug information.
568 void beginFunction(const MachineFunction *MF) override;
570 /// \brief Gather and emit post-function debug information.
571 void endFunction(const MachineFunction *MF) override;
573 /// \brief Process beginning of an instruction.
574 void beginInstruction(const MachineInstr *MI) override;
576 /// \brief Process end of an instruction.
577 void endInstruction() override;
579 /// \brief Add a DIE to the set of types that we're going to pull into
581 void addDwarfTypeUnitType(DwarfCompileUnit &CU, StringRef Identifier,
582 DIE &Die, DICompositeType CTy);
584 /// \brief Add a label so that arange data can be generated for it.
585 void addArangeLabel(SymbolCU SCU) { ArangeLabels.push_back(SCU); }
587 /// \brief For symbols that have a size designated (e.g. common symbols),
588 /// this tracks that size.
589 void setSymbolSize(const MCSymbol *Sym, uint64_t Size) override {
593 /// \brief Recursively Emits a debug information entry.
594 void emitDIE(DIE &Die);
596 // Experimental DWARF5 features.
598 /// \brief Returns whether or not to emit tables that dwarf consumers can
599 /// use to accelerate lookup.
600 bool useDwarfAccelTables() const { return HasDwarfAccelTables; }
602 /// \brief Returns whether or not to change the current debug info for the
603 /// split dwarf proposal support.
604 bool useSplitDwarf() const { return HasSplitDwarf; }
606 /// Returns the Dwarf Version.
607 unsigned getDwarfVersion() const { return DwarfVersion; }
609 /// Returns the section symbol for the .debug_loc section.
610 MCSymbol *getDebugLocSym() const { return DwarfDebugLocSectionSym; }
612 /// Returns the previous section that was emitted into.
613 const MCSection *getPrevSection() const { return PrevSection; }
615 /// Returns the previous CU that was being updated
616 const DwarfCompileUnit *getPrevCU() const { return PrevCU; }
618 /// Returns the entries for the .debug_loc section.
619 const SmallVectorImpl<DebugLocList> &
620 getDebugLocEntries() const {
621 return DotDebugLocEntries;
624 /// \brief Emit an entry for the debug loc section. This can be used to
625 /// handle an entry that's going to be emitted into the debug loc section.
626 void emitDebugLocEntry(ByteStreamer &Streamer, const DebugLocEntry &Entry);
628 /// Emit the location for a debug loc entry, including the size header.
629 void emitDebugLocEntryLocation(const DebugLocEntry &Entry);
631 /// Find the MDNode for the given reference.
632 template <typename T> T resolve(DIRef<T> Ref) const {
633 return Ref.resolve(TypeIdentifierMap);
636 /// \brief Return the TypeIdentifierMap.
637 const DITypeIdentifierMap &getTypeIdentifierMap() const {
638 return TypeIdentifierMap;
641 /// Find the DwarfCompileUnit for the given CU Die.
642 DwarfCompileUnit *lookupUnit(const DIE *CU) const {
643 return CUDieMap.lookup(CU);
645 /// isSubprogramContext - Return true if Context is either a subprogram
646 /// or another context nested inside a subprogram.
647 bool isSubprogramContext(const MDNode *Context);
649 void addSubprogramNames(DISubprogram SP, DIE &Die);
651 AddressPool &getAddressPool() { return AddrPool; }
653 void addAccelName(StringRef Name, const DIE &Die);
655 void addAccelObjC(StringRef Name, const DIE &Die);
657 void addAccelNamespace(StringRef Name, const DIE &Die);
659 void addAccelType(StringRef Name, const DIE &Die, char Flags);
661 } // End of namespace llvm