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 *DwarfTypesDWOSectionSym;
257 MCSymbol *DwarfStrDWOSectionSym;
258 MCSymbol *DwarfGnuPubNamesSectionSym, *DwarfGnuPubTypesSectionSym;
260 // As an optimization, there is no need to emit an entry in the directory
261 // table for the same directory as DW_AT_comp_dir.
262 StringRef CompilationDir;
264 // Counter for assigning globally unique IDs for ranges.
265 unsigned GlobalRangeCount;
267 // Holder for the file specific debug information.
268 DwarfFile InfoHolder;
270 // Holders for the various debug information flags that we might need to
271 // have exposed. See accessor functions below for description.
273 // Holder for imported entities.
274 typedef SmallVector<std::pair<const MDNode *, const MDNode *>, 32>
276 ImportedEntityMap ScopesWithImportedEntities;
278 // Map from MDNodes for user-defined types to the type units that describe
280 DenseMap<const MDNode *, const DwarfTypeUnit *> DwarfTypeUnits;
282 SmallVector<std::pair<std::unique_ptr<DwarfTypeUnit>, DICompositeType>, 1> TypeUnitsUnderConstruction;
284 // Whether to emit the pubnames/pubtypes sections.
285 bool HasDwarfPubSections;
287 // Whether or not to use AT_ranges for compilation units.
290 // Whether we emitted a function into a section other than the default
292 bool UsedNonDefaultText;
294 // Version of dwarf we're emitting.
295 unsigned DwarfVersion;
297 // Maps from a type identifier to the actual MDNode.
298 DITypeIdentifierMap TypeIdentifierMap;
300 // DWARF5 Experimental Options
301 bool HasDwarfAccelTables;
304 // Separated Dwarf Variables
305 // In general these will all be for bits that are left in the
306 // original object file, rather than things that are meant
307 // to be in the .dwo sections.
309 // Holder for the skeleton information.
310 DwarfFile SkeletonHolder;
312 /// Store file names for type units under fission in a line table header that
313 /// will be emitted into debug_line.dwo.
314 // FIXME: replace this with a map from comp_dir to table so that we can emit
315 // multiple tables during LTO each of which uses directory 0, referencing the
316 // comp_dir of all the type units that use it.
317 MCDwarfDwoLineTable SplitTypeUnitFileTable;
319 // True iff there are multiple CUs in this module.
322 AddressPool AddrPool;
324 DwarfAccelTable AccelNames;
325 DwarfAccelTable AccelObjC;
326 DwarfAccelTable AccelNamespace;
327 DwarfAccelTable AccelTypes;
329 MCDwarfDwoLineTable *getDwoLineTable(const DwarfCompileUnit &);
331 void addScopeVariable(LexicalScope *LS, DbgVariable *Var);
333 const SmallVectorImpl<std::unique_ptr<DwarfUnit>> &getUnits() {
334 return InfoHolder.getUnits();
337 /// \brief Find abstract variable associated with Var.
338 DbgVariable *findAbstractVariable(DIVariable &Var, DebugLoc Loc);
340 /// \brief Find DIE for the given subprogram and attach appropriate
341 /// DW_AT_low_pc and DW_AT_high_pc attributes. If there are global
342 /// variables in this scope then create and insert DIEs for these
344 DIE &updateSubprogramScopeDIE(DwarfCompileUnit &SPCU, DISubprogram SP);
346 /// \brief A helper function to check whether the DIE for a given Scope is
347 /// going to be null.
348 bool isLexicalScopeDIENull(LexicalScope *Scope);
350 /// \brief A helper function to construct a RangeSpanList for a given
352 void addScopeRangeList(DwarfCompileUnit &TheCU, DIE &ScopeDIE,
353 const SmallVectorImpl<InsnRange> &Range);
355 /// \brief Construct new DW_TAG_lexical_block for this scope and
356 /// attach DW_AT_low_pc/DW_AT_high_pc labels.
357 std::unique_ptr<DIE> constructLexicalScopeDIE(DwarfCompileUnit &TheCU,
358 LexicalScope *Scope);
360 /// \brief This scope represents inlined body of a function. Construct
361 /// DIE to represent this concrete inlined copy of the function.
362 std::unique_ptr<DIE> constructInlinedScopeDIE(DwarfCompileUnit &TheCU,
363 LexicalScope *Scope);
365 /// \brief Construct a DIE for this scope.
366 std::unique_ptr<DIE> constructScopeDIE(DwarfCompileUnit &TheCU,
367 LexicalScope *Scope);
368 void createAndAddScopeChildren(DwarfCompileUnit &TheCU, LexicalScope *Scope,
370 /// \brief Construct a DIE for this abstract scope.
371 void constructAbstractSubprogramScopeDIE(DwarfCompileUnit &TheCU,
372 LexicalScope *Scope);
373 /// \brief Construct a DIE for this subprogram scope.
374 DIE &constructSubprogramScopeDIE(DwarfCompileUnit &TheCU,
375 LexicalScope *Scope);
376 /// A helper function to create children of a Scope DIE.
377 DIE *createScopeChildrenDIE(DwarfCompileUnit &TheCU, LexicalScope *Scope,
378 SmallVectorImpl<std::unique_ptr<DIE>> &Children);
380 /// \brief Emit initial Dwarf sections with a label at the start of each one.
381 void emitSectionLabels();
383 /// \brief Compute the size and offset of a DIE given an incoming Offset.
384 unsigned computeSizeAndOffset(DIE *Die, unsigned Offset);
386 /// \brief Compute the size and offset of all the DIEs.
387 void computeSizeAndOffsets();
389 /// \brief Collect info for variables that were optimized out.
390 void collectDeadVariables();
392 /// \brief Finish off debug information after all functions have been
394 void finalizeModuleInfo();
396 /// \brief Emit labels to close any remaining sections that have been left
400 /// \brief Emit the debug info section.
401 void emitDebugInfo();
403 /// \brief Emit the abbreviation section.
404 void emitAbbreviations();
406 /// \brief Emit the last address of the section and the end of
408 void emitEndOfLineMatrix(unsigned SectionEnd);
410 /// \brief Emit visible names into a hashed accelerator table section.
411 void emitAccelNames();
413 /// \brief Emit objective C classes and categories into a hashed
414 /// accelerator table section.
415 void emitAccelObjC();
417 /// \brief Emit namespace dies into a hashed accelerator table.
418 void emitAccelNamespaces();
420 /// \brief Emit type dies into a hashed accelerator table.
421 void emitAccelTypes();
423 /// \brief Emit visible names into a debug pubnames section.
424 /// \param GnuStyle determines whether or not we want to emit
425 /// additional information into the table ala newer gcc for gdb
427 void emitDebugPubNames(bool GnuStyle = false);
429 /// \brief Emit visible types into a debug pubtypes section.
430 /// \param GnuStyle determines whether or not we want to emit
431 /// additional information into the table ala newer gcc for gdb
433 void emitDebugPubTypes(bool GnuStyle = false);
436 emitDebugPubSection(bool GnuStyle, const MCSection *PSec, StringRef Name,
437 const StringMap<const DIE *> &(DwarfUnit::*Accessor)()
440 /// \brief Emit visible names into a debug str section.
443 /// \brief Emit visible names into a debug loc section.
446 /// \brief Emit visible names into a debug loc dwo section.
447 void emitDebugLocDWO();
449 /// \brief Emit visible names into a debug aranges section.
450 void emitDebugARanges();
452 /// \brief Emit visible names into a debug ranges section.
453 void emitDebugRanges();
455 /// \brief Emit inline info using custom format.
456 void emitDebugInlineInfo();
458 /// DWARF 5 Experimental Split Dwarf Emitters
460 /// \brief Initialize common features of skeleton units.
461 void initSkeletonUnit(const DwarfUnit &U, DIE &Die,
462 std::unique_ptr<DwarfUnit> NewU);
464 /// \brief Construct the split debug info compile unit for the debug info
466 DwarfCompileUnit &constructSkeletonCU(const DwarfCompileUnit &CU);
468 /// \brief Construct the split debug info compile unit for the debug info
470 DwarfTypeUnit &constructSkeletonTU(DwarfTypeUnit &TU);
472 /// \brief Emit the debug info dwo section.
473 void emitDebugInfoDWO();
475 /// \brief Emit the debug abbrev dwo section.
476 void emitDebugAbbrevDWO();
478 /// \brief Emit the debug line dwo section.
479 void emitDebugLineDWO();
481 /// \brief Emit the debug str dwo section.
482 void emitDebugStrDWO();
484 /// Flags to let the linker know we have emitted new style pubnames. Only
485 /// emit it here if we don't have a skeleton CU for split dwarf.
486 void addGnuPubAttributes(DwarfUnit &U, DIE &D) const;
488 /// \brief Create new DwarfCompileUnit for the given metadata node with tag
489 /// DW_TAG_compile_unit.
490 DwarfCompileUnit &constructDwarfCompileUnit(DICompileUnit DIUnit);
492 /// \brief Construct subprogram DIE.
493 void constructSubprogramDIE(DwarfCompileUnit &TheCU, const MDNode *N);
495 /// \brief Construct imported_module or imported_declaration DIE.
496 void constructImportedEntityDIE(DwarfCompileUnit &TheCU, const MDNode *N);
498 /// \brief Construct import_module DIE.
499 void constructImportedEntityDIE(DwarfCompileUnit &TheCU, const MDNode *N,
502 /// \brief Construct import_module DIE.
503 void constructImportedEntityDIE(DwarfCompileUnit &TheCU,
504 const DIImportedEntity &Module, DIE &Context);
506 /// \brief Register a source line with debug info. Returns the unique
507 /// label that was emitted and which provides correspondence to the
508 /// source line list.
509 void recordSourceLine(unsigned Line, unsigned Col, const MDNode *Scope,
512 /// \brief Indentify instructions that are marking the beginning of or
513 /// ending of a scope.
514 void identifyScopeMarkers();
516 /// \brief If Var is an current function argument that add it in
517 /// CurrentFnArguments list.
518 bool addCurrentFnArgument(DbgVariable *Var, LexicalScope *Scope);
520 /// \brief Populate LexicalScope entries with variables' info.
521 void collectVariableInfo(SmallPtrSet<const MDNode *, 16> &ProcessedVars);
523 /// \brief Collect variable information from the side table maintained
525 void collectVariableInfoFromMMITable(SmallPtrSet<const MDNode *, 16> &P);
527 /// \brief Ensure that a label will be emitted before MI.
528 void requestLabelBeforeInsn(const MachineInstr *MI) {
529 LabelsBeforeInsn.insert(std::make_pair(MI, nullptr));
532 /// \brief Return Label preceding the instruction.
533 MCSymbol *getLabelBeforeInsn(const MachineInstr *MI);
535 /// \brief Ensure that a label will be emitted after MI.
536 void requestLabelAfterInsn(const MachineInstr *MI) {
537 LabelsAfterInsn.insert(std::make_pair(MI, nullptr));
540 /// \brief Return Label immediately following the instruction.
541 MCSymbol *getLabelAfterInsn(const MachineInstr *MI);
543 void attachLowHighPC(DwarfCompileUnit &Unit, DIE &D, MCSymbol *Begin,
547 //===--------------------------------------------------------------------===//
548 // Main entry points.
550 DwarfDebug(AsmPrinter *A, Module *M);
552 ~DwarfDebug() override;
554 void insertDIE(const MDNode *TypeMD, DIE *Die) {
555 MDTypeNodeToDieMap.insert(std::make_pair(TypeMD, Die));
557 DIE *getDIE(const MDNode *TypeMD) {
558 return MDTypeNodeToDieMap.lookup(TypeMD);
561 /// \brief Emit all Dwarf sections that should come prior to the
565 /// \brief Emit all Dwarf sections that should come after the content.
566 void endModule() override;
568 /// \brief Gather pre-function debug information.
569 void beginFunction(const MachineFunction *MF) override;
571 /// \brief Gather and emit post-function debug information.
572 void endFunction(const MachineFunction *MF) override;
574 /// \brief Process beginning of an instruction.
575 void beginInstruction(const MachineInstr *MI) override;
577 /// \brief Process end of an instruction.
578 void endInstruction() override;
580 /// \brief Add a DIE to the set of types that we're going to pull into
582 void addDwarfTypeUnitType(DwarfCompileUnit &CU, StringRef Identifier,
583 DIE &Die, DICompositeType CTy);
585 /// \brief Add a label so that arange data can be generated for it.
586 void addArangeLabel(SymbolCU SCU) { ArangeLabels.push_back(SCU); }
588 /// \brief For symbols that have a size designated (e.g. common symbols),
589 /// this tracks that size.
590 void setSymbolSize(const MCSymbol *Sym, uint64_t Size) override {
594 /// \brief Recursively Emits a debug information entry.
595 void emitDIE(DIE &Die);
597 // Experimental DWARF5 features.
599 /// \brief Returns whether or not to emit tables that dwarf consumers can
600 /// use to accelerate lookup.
601 bool useDwarfAccelTables() const { return HasDwarfAccelTables; }
603 /// \brief Returns whether or not to change the current debug info for the
604 /// split dwarf proposal support.
605 bool useSplitDwarf() const { return HasSplitDwarf; }
607 /// Returns the Dwarf Version.
608 unsigned getDwarfVersion() const { return DwarfVersion; }
610 /// Returns the section symbol for the .debug_loc section.
611 MCSymbol *getDebugLocSym() const { return DwarfDebugLocSectionSym; }
613 /// Returns the previous section that was emitted into.
614 const MCSection *getPrevSection() const { return PrevSection; }
616 /// Returns the previous CU that was being updated
617 const DwarfCompileUnit *getPrevCU() const { return PrevCU; }
619 /// Returns the entries for the .debug_loc section.
620 const SmallVectorImpl<DebugLocList> &
621 getDebugLocEntries() const {
622 return DotDebugLocEntries;
625 /// \brief Emit an entry for the debug loc section. This can be used to
626 /// handle an entry that's going to be emitted into the debug loc section.
627 void emitDebugLocEntry(ByteStreamer &Streamer, const DebugLocEntry &Entry);
629 /// Emit the location for a debug loc entry, including the size header.
630 void emitDebugLocEntryLocation(const DebugLocEntry &Entry);
632 /// Find the MDNode for the given reference.
633 template <typename T> T resolve(DIRef<T> Ref) const {
634 return Ref.resolve(TypeIdentifierMap);
637 /// \brief Return the TypeIdentifierMap.
638 const DITypeIdentifierMap &getTypeIdentifierMap() const {
639 return TypeIdentifierMap;
642 /// Find the DwarfCompileUnit for the given CU Die.
643 DwarfCompileUnit *lookupUnit(const DIE *CU) const {
644 return CUDieMap.lookup(CU);
646 /// isSubprogramContext - Return true if Context is either a subprogram
647 /// or another context nested inside a subprogram.
648 bool isSubprogramContext(const MDNode *Context);
650 void addSubprogramNames(DISubprogram SP, DIE &Die);
652 AddressPool &getAddressPool() { return AddrPool; }
654 void addAccelName(StringRef Name, const DIE &Die);
656 void addAccelObjC(StringRef Name, const DIE &Die);
658 void addAccelNamespace(StringRef Name, const DIE &Die);
660 void addAccelType(StringRef Name, const DIE &Die, char Flags);
662 } // End of namespace llvm