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 LLVM_LIB_CODEGEN_ASMPRINTER_DWARFDEBUG_H
15 #define LLVM_LIB_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/CodeGen/MachineInstr.h"
31 #include "llvm/IR/DebugInfo.h"
32 #include "llvm/IR/DebugLoc.h"
33 #include "llvm/MC/MachineLocation.h"
34 #include "llvm/MC/MCDwarf.h"
35 #include "llvm/Support/Allocator.h"
45 class DwarfCompileUnit;
49 class MachineModuleInfo;
51 //===----------------------------------------------------------------------===//
52 /// \brief This class is used to record source line correspondence.
54 unsigned Line; // Source line number.
55 unsigned Column; // Source column.
56 unsigned SourceID; // Source ID number.
57 MCSymbol *Label; // Label in code ID number.
59 SrcLineInfo(unsigned L, unsigned C, unsigned S, MCSymbol *label)
60 : Line(L), Column(C), SourceID(S), Label(label) {}
63 unsigned getLine() const { return Line; }
64 unsigned getColumn() const { return Column; }
65 unsigned getSourceID() const { return SourceID; }
66 MCSymbol *getLabel() const { return Label; }
69 //===----------------------------------------------------------------------===//
70 /// \brief This class is used to track local variable information.
72 DIVariable Var; // Variable Descriptor.
73 DIExpression Expr; // Complex address location expression.
74 DIE *TheDIE; // Variable DIE.
75 unsigned DotDebugLocOffset; // Offset in DotDebugLocEntries.
76 const MachineInstr *MInsn; // DBG_VALUE instruction of the variable.
81 /// Construct a DbgVariable from a DIVariable.
82 DbgVariable(DIVariable V, DIExpression E, DwarfDebug *DD)
83 : Var(V), Expr(E), TheDIE(nullptr), DotDebugLocOffset(~0U),
84 MInsn(nullptr), FrameIndex(~0), DD(DD) {
85 assert(Var.Verify() && Expr.Verify());
88 /// Construct a DbgVariable from a DEBUG_VALUE.
89 /// AbstractVar may be NULL.
90 DbgVariable(const MachineInstr *DbgValue, DwarfDebug *DD)
91 : Var(DbgValue->getDebugVariable()), Expr(DbgValue->getDebugExpression()),
92 TheDIE(nullptr), DotDebugLocOffset(~0U), MInsn(DbgValue),
93 FrameIndex(~0), DD(DD) {}
96 DIVariable getVariable() const { return Var; }
97 DIExpression getExpression() const { return Expr; }
98 void setDIE(DIE &D) { TheDIE = &D; }
99 DIE *getDIE() const { return TheDIE; }
100 void setDotDebugLocOffset(unsigned O) { DotDebugLocOffset = O; }
101 unsigned getDotDebugLocOffset() const { return DotDebugLocOffset; }
102 StringRef getName() const { return Var.getName(); }
103 const MachineInstr *getMInsn() const { return MInsn; }
104 int getFrameIndex() const { return FrameIndex; }
105 void setFrameIndex(int FI) { FrameIndex = FI; }
106 // Translate tag to proper Dwarf tag.
107 dwarf::Tag getTag() const {
108 if (Var.getTag() == dwarf::DW_TAG_arg_variable)
109 return dwarf::DW_TAG_formal_parameter;
111 return dwarf::DW_TAG_variable;
113 /// \brief Return true if DbgVariable is artificial.
114 bool isArtificial() const {
115 if (Var.isArtificial())
117 if (getType().isArtificial())
122 bool isObjectPointer() const {
123 if (Var.isObjectPointer())
125 if (getType().isObjectPointer())
130 bool variableHasComplexAddress() const {
131 assert(Var.isVariable() && "Invalid complex DbgVariable!");
132 return Expr.getNumElements() > 0;
134 bool isBlockByrefVariable() const;
135 unsigned getNumAddrElements() const {
136 assert(Var.isVariable() && "Invalid complex DbgVariable!");
137 return Expr.getNumElements();
139 uint64_t getAddrElement(unsigned i) const { return Expr.getElement(i); }
140 DIType getType() const;
143 /// resolve - Look in the DwarfDebug map for the MDNode that
144 /// corresponds to the reference.
145 template <typename T> T resolve(DIRef<T> Ref) const;
149 /// \brief Helper used to pair up a symbol and its DWARF compile unit.
151 SymbolCU(DwarfCompileUnit *CU, const MCSymbol *Sym) : Sym(Sym), CU(CU) {}
153 DwarfCompileUnit *CU;
156 /// \brief Collects and handles dwarf debug information.
157 class DwarfDebug : public AsmPrinterHandler {
158 // Target of Dwarf emission.
161 // Collected machine module information.
162 MachineModuleInfo *MMI;
164 // All DIEValues are allocated through this allocator.
165 BumpPtrAllocator DIEValueAllocator;
167 // Maps MDNode with its corresponding DwarfCompileUnit.
168 MapVector<const MDNode *, DwarfCompileUnit *> CUMap;
170 // Maps subprogram MDNode with its corresponding DwarfCompileUnit.
171 MapVector<const MDNode *, DwarfCompileUnit *> SPMap;
173 // Maps a CU DIE with its corresponding DwarfCompileUnit.
174 DenseMap<const DIE *, DwarfCompileUnit *> CUDieMap;
176 /// Maps MDNodes for type system with the corresponding DIEs. These DIEs can
177 /// be shared across CUs, that is why we keep the map here instead
178 /// of in DwarfCompileUnit.
179 DenseMap<const MDNode *, DIE *> MDTypeNodeToDieMap;
181 // List of all labels used in aranges generation.
182 std::vector<SymbolCU> ArangeLabels;
184 // Size of each symbol emitted (for those symbols that have a specific size).
185 DenseMap<const MCSymbol *, uint64_t> SymSize;
187 // Provides a unique id per text section.
188 typedef DenseMap<const MCSection *, SmallVector<SymbolCU, 8> > SectionMapType;
189 SectionMapType SectionMap;
191 LexicalScopes LScopes;
193 // Collection of abstract subprogram DIEs.
194 DenseMap<const MDNode *, DIE *> AbstractSPDies;
196 // Collection of abstract variables.
197 DenseMap<const MDNode *, std::unique_ptr<DbgVariable>> AbstractVariables;
198 SmallVector<std::unique_ptr<DbgVariable>, 64> ConcreteVariables;
200 // Collection of DebugLocEntry. Stored in a linked list so that DIELocLists
201 // can refer to them in spite of insertions into this list.
202 SmallVector<DebugLocList, 4> DotDebugLocEntries;
204 // This is a collection of subprogram MDNodes that are processed to
206 SmallPtrSet<const MDNode *, 16> ProcessedSPNodes;
208 // Maps instruction with label emitted before instruction.
209 DenseMap<const MachineInstr *, MCSymbol *> LabelsBeforeInsn;
211 // Maps instruction with label emitted after instruction.
212 DenseMap<const MachineInstr *, MCSymbol *> LabelsAfterInsn;
214 // History of DBG_VALUE and clobber instructions for each user variable.
215 // Variables are listed in order of appearance.
216 DbgValueHistoryMap DbgValues;
218 // Previous instruction's location information. This is used to determine
219 // label location to indicate scope boundries in dwarf debug info.
220 DebugLoc PrevInstLoc;
223 // This location indicates end of function prologue and beginning of function
225 DebugLoc PrologEndLoc;
227 // If nonnull, stores the current machine function we're processing.
228 const MachineFunction *CurFn;
230 // If nonnull, stores the current machine instruction we're processing.
231 const MachineInstr *CurMI;
233 // If nonnull, stores the CU in which the previous subprogram was contained.
234 const DwarfCompileUnit *PrevCU;
236 // Section Symbols: these are assembler temporary labels that are emitted at
237 // the beginning of each supported dwarf section. These are used to form
238 // section offsets and are created by EmitSectionLabels.
239 MCSymbol *DwarfInfoSectionSym, *DwarfAbbrevSectionSym;
240 MCSymbol *DwarfStrSectionSym, *TextSectionSym, *DwarfDebugRangeSectionSym;
241 MCSymbol *DwarfDebugLocSectionSym, *DwarfLineSectionSym, *DwarfAddrSectionSym;
242 MCSymbol *FunctionBeginSym, *FunctionEndSym;
243 MCSymbol *DwarfInfoDWOSectionSym, *DwarfAbbrevDWOSectionSym;
244 MCSymbol *DwarfTypesDWOSectionSym;
245 MCSymbol *DwarfStrDWOSectionSym;
246 MCSymbol *DwarfGnuPubNamesSectionSym, *DwarfGnuPubTypesSectionSym;
248 // As an optimization, there is no need to emit an entry in the directory
249 // table for the same directory as DW_AT_comp_dir.
250 StringRef CompilationDir;
252 // Counter for assigning globally unique IDs for ranges.
253 unsigned GlobalRangeCount;
255 // Holder for the file specific debug information.
256 DwarfFile InfoHolder;
258 // Holders for the various debug information flags that we might need to
259 // have exposed. See accessor functions below for description.
261 // Holder for imported entities.
262 typedef SmallVector<std::pair<const MDNode *, const MDNode *>, 32>
264 ImportedEntityMap ScopesWithImportedEntities;
266 // Map from MDNodes for user-defined types to the type units that describe
268 DenseMap<const MDNode *, const DwarfTypeUnit *> DwarfTypeUnits;
270 SmallVector<std::pair<std::unique_ptr<DwarfTypeUnit>, DICompositeType>, 1> TypeUnitsUnderConstruction;
272 // Whether to emit the pubnames/pubtypes sections.
273 bool HasDwarfPubSections;
275 // Whether or not to use AT_ranges for compilation units.
278 // Whether we emitted a function into a section other than the default
280 bool UsedNonDefaultText;
282 // Version of dwarf we're emitting.
283 unsigned DwarfVersion;
285 // Maps from a type identifier to the actual MDNode.
286 DITypeIdentifierMap TypeIdentifierMap;
288 // DWARF5 Experimental Options
289 bool HasDwarfAccelTables;
292 // Separated Dwarf Variables
293 // In general these will all be for bits that are left in the
294 // original object file, rather than things that are meant
295 // to be in the .dwo sections.
297 // Holder for the skeleton information.
298 DwarfFile SkeletonHolder;
300 /// Store file names for type units under fission in a line table header that
301 /// will be emitted into debug_line.dwo.
302 // FIXME: replace this with a map from comp_dir to table so that we can emit
303 // multiple tables during LTO each of which uses directory 0, referencing the
304 // comp_dir of all the type units that use it.
305 MCDwarfDwoLineTable SplitTypeUnitFileTable;
307 // True iff there are multiple CUs in this module.
311 AddressPool AddrPool;
313 DwarfAccelTable AccelNames;
314 DwarfAccelTable AccelObjC;
315 DwarfAccelTable AccelNamespace;
316 DwarfAccelTable AccelTypes;
318 DenseMap<const Function *, DISubprogram> FunctionDIs;
320 MCDwarfDwoLineTable *getDwoLineTable(const DwarfCompileUnit &);
322 const SmallVectorImpl<std::unique_ptr<DwarfUnit>> &getUnits() {
323 return InfoHolder.getUnits();
326 /// \brief Find abstract variable associated with Var.
327 DbgVariable *getExistingAbstractVariable(const DIVariable &DV,
328 DIVariable &Cleansed);
329 DbgVariable *getExistingAbstractVariable(const DIVariable &DV);
330 void createAbstractVariable(const DIVariable &DV, LexicalScope *Scope);
331 void ensureAbstractVariableIsCreated(const DIVariable &Var,
332 const MDNode *Scope);
333 void ensureAbstractVariableIsCreatedIfScoped(const DIVariable &Var,
334 const MDNode *Scope);
336 /// \brief Construct a DIE for this abstract scope.
337 void constructAbstractSubprogramScopeDIE(LexicalScope *Scope);
339 /// \brief Emit initial Dwarf sections with a label at the start of each one.
340 void emitSectionLabels();
342 /// \brief Compute the size and offset of a DIE given an incoming Offset.
343 unsigned computeSizeAndOffset(DIE *Die, unsigned Offset);
345 /// \brief Compute the size and offset of all the DIEs.
346 void computeSizeAndOffsets();
348 /// \brief Collect info for variables that were optimized out.
349 void collectDeadVariables();
351 void finishVariableDefinitions();
353 void finishSubprogramDefinitions();
355 /// \brief Finish off debug information after all functions have been
357 void finalizeModuleInfo();
359 /// \brief Emit labels to close any remaining sections that have been left
363 /// \brief Emit the debug info section.
364 void emitDebugInfo();
366 /// \brief Emit the abbreviation section.
367 void emitAbbreviations();
369 /// \brief Emit the last address of the section and the end of
371 void emitEndOfLineMatrix(unsigned SectionEnd);
373 /// \brief Emit a specified accelerator table.
374 void emitAccel(DwarfAccelTable &Accel, const MCSection *Section,
375 StringRef TableName, StringRef SymName);
377 /// \brief Emit visible names into a hashed accelerator table section.
378 void emitAccelNames();
380 /// \brief Emit objective C classes and categories into a hashed
381 /// accelerator table section.
382 void emitAccelObjC();
384 /// \brief Emit namespace dies into a hashed accelerator table.
385 void emitAccelNamespaces();
387 /// \brief Emit type dies into a hashed accelerator table.
388 void emitAccelTypes();
390 /// \brief Emit visible names into a debug pubnames section.
391 /// \param GnuStyle determines whether or not we want to emit
392 /// additional information into the table ala newer gcc for gdb
394 void emitDebugPubNames(bool GnuStyle = false);
396 /// \brief Emit visible types into a debug pubtypes section.
397 /// \param GnuStyle determines whether or not we want to emit
398 /// additional information into the table ala newer gcc for gdb
400 void emitDebugPubTypes(bool GnuStyle = false);
403 emitDebugPubSection(bool GnuStyle, const MCSection *PSec, StringRef Name,
404 const StringMap<const DIE *> &(DwarfUnit::*Accessor)()
407 /// \brief Emit visible names into a debug str section.
410 /// \brief Emit visible names into a debug loc section.
413 /// \brief Emit visible names into a debug loc dwo section.
414 void emitDebugLocDWO();
416 /// \brief Emit visible names into a debug aranges section.
417 void emitDebugARanges();
419 /// \brief Emit visible names into a debug ranges section.
420 void emitDebugRanges();
422 /// \brief Emit inline info using custom format.
423 void emitDebugInlineInfo();
425 /// DWARF 5 Experimental Split Dwarf Emitters
427 /// \brief Initialize common features of skeleton units.
428 void initSkeletonUnit(const DwarfUnit &U, DIE &Die,
429 std::unique_ptr<DwarfUnit> NewU);
431 /// \brief Construct the split debug info compile unit for the debug info
433 DwarfCompileUnit &constructSkeletonCU(const DwarfCompileUnit &CU);
435 /// \brief Construct the split debug info compile unit for the debug info
437 DwarfTypeUnit &constructSkeletonTU(DwarfTypeUnit &TU);
439 /// \brief Emit the debug info dwo section.
440 void emitDebugInfoDWO();
442 /// \brief Emit the debug abbrev dwo section.
443 void emitDebugAbbrevDWO();
445 /// \brief Emit the debug line dwo section.
446 void emitDebugLineDWO();
448 /// \brief Emit the debug str dwo section.
449 void emitDebugStrDWO();
451 /// Flags to let the linker know we have emitted new style pubnames. Only
452 /// emit it here if we don't have a skeleton CU for split dwarf.
453 void addGnuPubAttributes(DwarfUnit &U, DIE &D) const;
455 /// \brief Create new DwarfCompileUnit for the given metadata node with tag
456 /// DW_TAG_compile_unit.
457 DwarfCompileUnit &constructDwarfCompileUnit(DICompileUnit DIUnit);
459 /// \brief Construct imported_module or imported_declaration DIE.
460 void constructAndAddImportedEntityDIE(DwarfCompileUnit &TheCU,
463 /// \brief Register a source line with debug info. Returns the unique
464 /// label that was emitted and which provides correspondence to the
465 /// source line list.
466 void recordSourceLine(unsigned Line, unsigned Col, const MDNode *Scope,
469 /// \brief Indentify instructions that are marking the beginning of or
470 /// ending of a scope.
471 void identifyScopeMarkers();
473 /// \brief Populate LexicalScope entries with variables' info.
474 void collectVariableInfo(DwarfCompileUnit &TheCU, DISubprogram SP,
475 SmallPtrSetImpl<const MDNode *> &ProcessedVars);
477 /// \brief Build the location list for all DBG_VALUEs in the
478 /// function that describe the same variable.
479 void buildLocationList(SmallVectorImpl<DebugLocEntry> &DebugLoc,
480 const DbgValueHistoryMap::InstrRanges &Ranges);
482 /// \brief Collect variable information from the side table maintained
484 void collectVariableInfoFromMMITable(SmallPtrSetImpl<const MDNode *> &P);
486 /// \brief Ensure that a label will be emitted before MI.
487 void requestLabelBeforeInsn(const MachineInstr *MI) {
488 LabelsBeforeInsn.insert(std::make_pair(MI, nullptr));
491 /// \brief Ensure that a label will be emitted after MI.
492 void requestLabelAfterInsn(const MachineInstr *MI) {
493 LabelsAfterInsn.insert(std::make_pair(MI, nullptr));
497 //===--------------------------------------------------------------------===//
498 // Main entry points.
500 DwarfDebug(AsmPrinter *A, Module *M);
502 ~DwarfDebug() override;
504 void insertDIE(const MDNode *TypeMD, DIE *Die) {
505 MDTypeNodeToDieMap.insert(std::make_pair(TypeMD, Die));
507 DIE *getDIE(const MDNode *TypeMD) {
508 return MDTypeNodeToDieMap.lookup(TypeMD);
511 /// \brief Emit all Dwarf sections that should come prior to the
515 /// \brief Emit all Dwarf sections that should come after the content.
516 void endModule() override;
518 /// \brief Gather pre-function debug information.
519 void beginFunction(const MachineFunction *MF) override;
521 /// \brief Gather and emit post-function debug information.
522 void endFunction(const MachineFunction *MF) override;
524 /// \brief Process beginning of an instruction.
525 void beginInstruction(const MachineInstr *MI) override;
527 /// \brief Process end of an instruction.
528 void endInstruction() override;
530 /// \brief Add a DIE to the set of types that we're going to pull into
532 void addDwarfTypeUnitType(DwarfCompileUnit &CU, StringRef Identifier,
533 DIE &Die, DICompositeType CTy);
535 /// \brief Add a label so that arange data can be generated for it.
536 void addArangeLabel(SymbolCU SCU) { ArangeLabels.push_back(SCU); }
538 /// \brief For symbols that have a size designated (e.g. common symbols),
539 /// this tracks that size.
540 void setSymbolSize(const MCSymbol *Sym, uint64_t Size) override {
544 /// \brief Recursively Emits a debug information entry.
545 void emitDIE(DIE &Die);
547 // Experimental DWARF5 features.
549 /// \brief Returns whether or not to emit tables that dwarf consumers can
550 /// use to accelerate lookup.
551 bool useDwarfAccelTables() const { return HasDwarfAccelTables; }
553 /// \brief Returns whether or not to change the current debug info for the
554 /// split dwarf proposal support.
555 bool useSplitDwarf() const { return HasSplitDwarf; }
557 /// Returns the Dwarf Version.
558 unsigned getDwarfVersion() const { return DwarfVersion; }
560 /// Returns the section symbol for the .debug_loc section.
561 MCSymbol *getDebugLocSym() const { return DwarfDebugLocSectionSym; }
563 /// Returns the section symbol for the .debug_str section.
564 MCSymbol *getDebugStrSym() const { return DwarfStrSectionSym; }
566 /// Returns the section symbol for the .debug_ranges section.
567 MCSymbol *getRangeSectionSym() const { return DwarfDebugRangeSectionSym; }
569 /// Returns the previous CU that was being updated
570 const DwarfCompileUnit *getPrevCU() const { return PrevCU; }
571 void setPrevCU(const DwarfCompileUnit *PrevCU) { this->PrevCU = PrevCU; }
573 /// Returns the entries for the .debug_loc section.
574 const SmallVectorImpl<DebugLocList> &
575 getDebugLocEntries() const {
576 return DotDebugLocEntries;
579 /// \brief Emit an entry for the debug loc section. This can be used to
580 /// handle an entry that's going to be emitted into the debug loc section.
581 void emitDebugLocEntry(ByteStreamer &Streamer, const DebugLocEntry &Entry);
582 /// \brief emit a single value for the debug loc section.
583 void emitDebugLocValue(ByteStreamer &Streamer,
584 const DebugLocEntry::Value &Value);
585 /// Emits an optimal (=sorted) sequence of DW_OP_pieces.
586 void emitLocPieces(ByteStreamer &Streamer,
587 const DITypeIdentifierMap &Map,
588 ArrayRef<DebugLocEntry::Value> Values);
590 /// Emit the location for a debug loc entry, including the size header.
591 void emitDebugLocEntryLocation(const DebugLocEntry &Entry);
593 /// Find the MDNode for the given reference.
594 template <typename T> T resolve(DIRef<T> Ref) const {
595 return Ref.resolve(TypeIdentifierMap);
598 /// \brief Return the TypeIdentifierMap.
599 const DITypeIdentifierMap &getTypeIdentifierMap() const {
600 return TypeIdentifierMap;
603 /// Find the DwarfCompileUnit for the given CU Die.
604 DwarfCompileUnit *lookupUnit(const DIE *CU) const {
605 return CUDieMap.lookup(CU);
607 /// isSubprogramContext - Return true if Context is either a subprogram
608 /// or another context nested inside a subprogram.
609 bool isSubprogramContext(const MDNode *Context);
611 void addSubprogramNames(DISubprogram SP, DIE &Die);
613 AddressPool &getAddressPool() { return AddrPool; }
615 void addAccelName(StringRef Name, const DIE &Die);
617 void addAccelObjC(StringRef Name, const DIE &Die);
619 void addAccelNamespace(StringRef Name, const DIE &Die);
621 void addAccelType(StringRef Name, const DIE &Die, char Flags);
623 const MachineFunction *getCurrentFunction() const { return CurFn; }
624 const MCSymbol *getFunctionBeginSym() const { return FunctionBeginSym; }
625 const MCSymbol *getFunctionEndSym() const { return FunctionEndSym; }
627 iterator_range<ImportedEntityMap::const_iterator>
628 findImportedEntitiesForScope(const MDNode *Scope) const {
629 return make_range(std::equal_range(
630 ScopesWithImportedEntities.begin(), ScopesWithImportedEntities.end(),
631 std::pair<const MDNode *, const MDNode *>(Scope, nullptr),
635 /// \brief A helper function to check whether the DIE for a given Scope is
636 /// going to be null.
637 bool isLexicalScopeDIENull(LexicalScope *Scope);
639 /// \brief Return Label preceding the instruction.
640 MCSymbol *getLabelBeforeInsn(const MachineInstr *MI);
642 /// \brief Return Label immediately following the instruction.
643 MCSymbol *getLabelAfterInsn(const MachineInstr *MI);
645 // FIXME: Consider rolling ranges up into DwarfDebug since we use a single
646 // range_base anyway, so there's no need to keep them as separate per-CU range
647 // lists. (though one day we might end up with a range.dwo section, in which
648 // case it'd go to DwarfFile)
649 unsigned getNextRangeNumber() { return GlobalRangeCount++; }
651 // FIXME: Sink these functions down into DwarfFile/Dwarf*Unit.
653 DenseMap<const MDNode *, DIE *> &getAbstractSPDies() {
654 return AbstractSPDies;
657 SmallPtrSet<const MDNode *, 16> &getProcessedSPNodes() {
658 return ProcessedSPNodes;
661 } // End of namespace llvm