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 // List of all labels used in aranges generation.
177 std::vector<SymbolCU> ArangeLabels;
179 // Size of each symbol emitted (for those symbols that have a specific size).
180 DenseMap<const MCSymbol *, uint64_t> SymSize;
182 // Provides a unique id per text section.
183 typedef DenseMap<const MCSection *, SmallVector<SymbolCU, 8> > SectionMapType;
184 SectionMapType SectionMap;
186 LexicalScopes LScopes;
188 // Collection of abstract variables.
189 DenseMap<const MDNode *, std::unique_ptr<DbgVariable>> AbstractVariables;
190 SmallVector<std::unique_ptr<DbgVariable>, 64> ConcreteVariables;
192 // Collection of DebugLocEntry. Stored in a linked list so that DIELocLists
193 // can refer to them in spite of insertions into this list.
194 SmallVector<DebugLocList, 4> DotDebugLocEntries;
196 // This is a collection of subprogram MDNodes that are processed to
198 SmallPtrSet<const MDNode *, 16> ProcessedSPNodes;
200 // Maps instruction with label emitted before instruction.
201 DenseMap<const MachineInstr *, MCSymbol *> LabelsBeforeInsn;
203 // Maps instruction with label emitted after instruction.
204 DenseMap<const MachineInstr *, MCSymbol *> LabelsAfterInsn;
206 // History of DBG_VALUE and clobber instructions for each user variable.
207 // Variables are listed in order of appearance.
208 DbgValueHistoryMap DbgValues;
210 // Previous instruction's location information. This is used to determine
211 // label location to indicate scope boundries in dwarf debug info.
212 DebugLoc PrevInstLoc;
215 // This location indicates end of function prologue and beginning of function
217 DebugLoc PrologEndLoc;
219 // If nonnull, stores the current machine function we're processing.
220 const MachineFunction *CurFn;
222 // If nonnull, stores the current machine instruction we're processing.
223 const MachineInstr *CurMI;
225 // If nonnull, stores the CU in which the previous subprogram was contained.
226 const DwarfCompileUnit *PrevCU;
228 // Section Symbols: these are assembler temporary labels that are emitted at
229 // the beginning of each supported dwarf section. These are used to form
230 // section offsets and are created by EmitSectionLabels.
231 MCSymbol *DwarfInfoSectionSym, *DwarfAbbrevSectionSym;
232 MCSymbol *DwarfStrSectionSym, *TextSectionSym, *DwarfDebugRangeSectionSym;
233 MCSymbol *DwarfDebugLocSectionSym, *DwarfLineSectionSym, *DwarfAddrSectionSym;
234 MCSymbol *FunctionBeginSym, *FunctionEndSym;
235 MCSymbol *DwarfInfoDWOSectionSym, *DwarfAbbrevDWOSectionSym;
236 MCSymbol *DwarfTypesDWOSectionSym;
237 MCSymbol *DwarfStrDWOSectionSym;
238 MCSymbol *DwarfGnuPubNamesSectionSym, *DwarfGnuPubTypesSectionSym;
240 // As an optimization, there is no need to emit an entry in the directory
241 // table for the same directory as DW_AT_comp_dir.
242 StringRef CompilationDir;
244 // Counter for assigning globally unique IDs for ranges.
245 unsigned GlobalRangeCount;
247 // Holder for the file specific debug information.
248 DwarfFile InfoHolder;
250 // Holders for the various debug information flags that we might need to
251 // have exposed. See accessor functions below for description.
253 // Holder for imported entities.
254 typedef SmallVector<std::pair<const MDNode *, const MDNode *>, 32>
256 ImportedEntityMap ScopesWithImportedEntities;
258 // Map from MDNodes for user-defined types to the type units that describe
260 DenseMap<const MDNode *, const DwarfTypeUnit *> DwarfTypeUnits;
262 SmallVector<std::pair<std::unique_ptr<DwarfTypeUnit>, DICompositeType>, 1> TypeUnitsUnderConstruction;
264 // Whether to emit the pubnames/pubtypes sections.
265 bool HasDwarfPubSections;
267 // Whether or not to use AT_ranges for compilation units.
270 // Whether we emitted a function into a section other than the default
272 bool UsedNonDefaultText;
274 // Version of dwarf we're emitting.
275 unsigned DwarfVersion;
277 // Maps from a type identifier to the actual MDNode.
278 DITypeIdentifierMap TypeIdentifierMap;
280 // DWARF5 Experimental Options
281 bool HasDwarfAccelTables;
284 // Separated Dwarf Variables
285 // In general these will all be for bits that are left in the
286 // original object file, rather than things that are meant
287 // to be in the .dwo sections.
289 // Holder for the skeleton information.
290 DwarfFile SkeletonHolder;
292 /// Store file names for type units under fission in a line table header that
293 /// will be emitted into debug_line.dwo.
294 // FIXME: replace this with a map from comp_dir to table so that we can emit
295 // multiple tables during LTO each of which uses directory 0, referencing the
296 // comp_dir of all the type units that use it.
297 MCDwarfDwoLineTable SplitTypeUnitFileTable;
299 // True iff there are multiple CUs in this module.
303 AddressPool AddrPool;
305 DwarfAccelTable AccelNames;
306 DwarfAccelTable AccelObjC;
307 DwarfAccelTable AccelNamespace;
308 DwarfAccelTable AccelTypes;
310 DenseMap<const Function *, DISubprogram> FunctionDIs;
312 MCDwarfDwoLineTable *getDwoLineTable(const DwarfCompileUnit &);
314 const SmallVectorImpl<std::unique_ptr<DwarfUnit>> &getUnits() {
315 return InfoHolder.getUnits();
318 /// \brief Find abstract variable associated with Var.
319 DbgVariable *getExistingAbstractVariable(const DIVariable &DV,
320 DIVariable &Cleansed);
321 DbgVariable *getExistingAbstractVariable(const DIVariable &DV);
322 void createAbstractVariable(const DIVariable &DV, LexicalScope *Scope);
323 void ensureAbstractVariableIsCreated(const DIVariable &Var,
324 const MDNode *Scope);
325 void ensureAbstractVariableIsCreatedIfScoped(const DIVariable &Var,
326 const MDNode *Scope);
328 /// \brief Construct a DIE for this abstract scope.
329 void constructAbstractSubprogramScopeDIE(LexicalScope *Scope);
331 /// \brief Emit initial Dwarf sections with a label at the start of each one.
332 void emitSectionLabels();
334 /// \brief Compute the size and offset of a DIE given an incoming Offset.
335 unsigned computeSizeAndOffset(DIE *Die, unsigned Offset);
337 /// \brief Compute the size and offset of all the DIEs.
338 void computeSizeAndOffsets();
340 /// \brief Collect info for variables that were optimized out.
341 void collectDeadVariables();
343 void finishVariableDefinitions();
345 void finishSubprogramDefinitions();
347 /// \brief Finish off debug information after all functions have been
349 void finalizeModuleInfo();
351 /// \brief Emit labels to close any remaining sections that have been left
355 /// \brief Emit the debug info section.
356 void emitDebugInfo();
358 /// \brief Emit the abbreviation section.
359 void emitAbbreviations();
361 /// \brief Emit the last address of the section and the end of
363 void emitEndOfLineMatrix(unsigned SectionEnd);
365 /// \brief Emit a specified accelerator table.
366 void emitAccel(DwarfAccelTable &Accel, const MCSection *Section,
367 StringRef TableName, StringRef SymName);
369 /// \brief Emit visible names into a hashed accelerator table section.
370 void emitAccelNames();
372 /// \brief Emit objective C classes and categories into a hashed
373 /// accelerator table section.
374 void emitAccelObjC();
376 /// \brief Emit namespace dies into a hashed accelerator table.
377 void emitAccelNamespaces();
379 /// \brief Emit type dies into a hashed accelerator table.
380 void emitAccelTypes();
382 /// \brief Emit visible names into a debug pubnames section.
383 /// \param GnuStyle determines whether or not we want to emit
384 /// additional information into the table ala newer gcc for gdb
386 void emitDebugPubNames(bool GnuStyle = false);
388 /// \brief Emit visible types into a debug pubtypes section.
389 /// \param GnuStyle determines whether or not we want to emit
390 /// additional information into the table ala newer gcc for gdb
392 void emitDebugPubTypes(bool GnuStyle = false);
394 void emitDebugPubSection(
395 bool GnuStyle, const MCSection *PSec, StringRef Name,
396 const StringMap<const DIE *> &(DwarfCompileUnit::*Accessor)() const);
398 /// \brief Emit visible names into a debug str section.
401 /// \brief Emit visible names into a debug loc section.
404 /// \brief Emit visible names into a debug loc dwo section.
405 void emitDebugLocDWO();
407 /// \brief Emit visible names into a debug aranges section.
408 void emitDebugARanges();
410 /// \brief Emit visible names into a debug ranges section.
411 void emitDebugRanges();
413 /// \brief Emit inline info using custom format.
414 void emitDebugInlineInfo();
416 /// DWARF 5 Experimental Split Dwarf Emitters
418 /// \brief Initialize common features of skeleton units.
419 void initSkeletonUnit(const DwarfUnit &U, DIE &Die,
420 std::unique_ptr<DwarfUnit> NewU);
422 /// \brief Construct the split debug info compile unit for the debug info
424 DwarfCompileUnit &constructSkeletonCU(const DwarfCompileUnit &CU);
426 /// \brief Construct the split debug info compile unit for the debug info
428 DwarfTypeUnit &constructSkeletonTU(DwarfTypeUnit &TU);
430 /// \brief Emit the debug info dwo section.
431 void emitDebugInfoDWO();
433 /// \brief Emit the debug abbrev dwo section.
434 void emitDebugAbbrevDWO();
436 /// \brief Emit the debug line dwo section.
437 void emitDebugLineDWO();
439 /// \brief Emit the debug str dwo section.
440 void emitDebugStrDWO();
442 /// Flags to let the linker know we have emitted new style pubnames. Only
443 /// emit it here if we don't have a skeleton CU for split dwarf.
444 void addGnuPubAttributes(DwarfUnit &U, DIE &D) const;
446 /// \brief Create new DwarfCompileUnit for the given metadata node with tag
447 /// DW_TAG_compile_unit.
448 DwarfCompileUnit &constructDwarfCompileUnit(DICompileUnit DIUnit);
450 /// \brief Construct imported_module or imported_declaration DIE.
451 void constructAndAddImportedEntityDIE(DwarfCompileUnit &TheCU,
454 /// \brief Register a source line with debug info. Returns the unique
455 /// label that was emitted and which provides correspondence to the
456 /// source line list.
457 void recordSourceLine(unsigned Line, unsigned Col, const MDNode *Scope,
460 /// \brief Indentify instructions that are marking the beginning of or
461 /// ending of a scope.
462 void identifyScopeMarkers();
464 /// \brief Populate LexicalScope entries with variables' info.
465 void collectVariableInfo(DwarfCompileUnit &TheCU, DISubprogram SP,
466 SmallPtrSetImpl<const MDNode *> &ProcessedVars);
468 /// \brief Build the location list for all DBG_VALUEs in the
469 /// function that describe the same variable.
470 void buildLocationList(SmallVectorImpl<DebugLocEntry> &DebugLoc,
471 const DbgValueHistoryMap::InstrRanges &Ranges);
473 /// \brief Collect variable information from the side table maintained
475 void collectVariableInfoFromMMITable(SmallPtrSetImpl<const MDNode *> &P);
477 /// \brief Ensure that a label will be emitted before MI.
478 void requestLabelBeforeInsn(const MachineInstr *MI) {
479 LabelsBeforeInsn.insert(std::make_pair(MI, nullptr));
482 /// \brief Ensure that a label will be emitted after MI.
483 void requestLabelAfterInsn(const MachineInstr *MI) {
484 LabelsAfterInsn.insert(std::make_pair(MI, nullptr));
488 //===--------------------------------------------------------------------===//
489 // Main entry points.
491 DwarfDebug(AsmPrinter *A, Module *M);
493 ~DwarfDebug() override;
495 /// \brief Emit all Dwarf sections that should come prior to the
499 /// \brief Emit all Dwarf sections that should come after the content.
500 void endModule() override;
502 /// \brief Gather pre-function debug information.
503 void beginFunction(const MachineFunction *MF) override;
505 /// \brief Gather and emit post-function debug information.
506 void endFunction(const MachineFunction *MF) override;
508 /// \brief Process beginning of an instruction.
509 void beginInstruction(const MachineInstr *MI) override;
511 /// \brief Process end of an instruction.
512 void endInstruction() override;
514 /// \brief Add a DIE to the set of types that we're going to pull into
516 void addDwarfTypeUnitType(DwarfCompileUnit &CU, StringRef Identifier,
517 DIE &Die, DICompositeType CTy);
519 /// \brief Add a label so that arange data can be generated for it.
520 void addArangeLabel(SymbolCU SCU) { ArangeLabels.push_back(SCU); }
522 /// \brief For symbols that have a size designated (e.g. common symbols),
523 /// this tracks that size.
524 void setSymbolSize(const MCSymbol *Sym, uint64_t Size) override {
528 /// \brief Recursively Emits a debug information entry.
529 void emitDIE(DIE &Die);
531 // Experimental DWARF5 features.
533 /// \brief Returns whether or not to emit tables that dwarf consumers can
534 /// use to accelerate lookup.
535 bool useDwarfAccelTables() const { return HasDwarfAccelTables; }
537 /// \brief Returns whether or not to change the current debug info for the
538 /// split dwarf proposal support.
539 bool useSplitDwarf() const { return HasSplitDwarf; }
541 /// Returns the Dwarf Version.
542 unsigned getDwarfVersion() const { return DwarfVersion; }
544 /// Returns the section symbol for the .debug_loc section.
545 MCSymbol *getDebugLocSym() const { return DwarfDebugLocSectionSym; }
547 /// Returns the section symbol for the .debug_str section.
548 MCSymbol *getDebugStrSym() const { return DwarfStrSectionSym; }
550 /// Returns the section symbol for the .debug_ranges section.
551 MCSymbol *getRangeSectionSym() const { return DwarfDebugRangeSectionSym; }
553 /// Returns the previous CU that was being updated
554 const DwarfCompileUnit *getPrevCU() const { return PrevCU; }
555 void setPrevCU(const DwarfCompileUnit *PrevCU) { this->PrevCU = PrevCU; }
557 /// Returns the entries for the .debug_loc section.
558 const SmallVectorImpl<DebugLocList> &
559 getDebugLocEntries() const {
560 return DotDebugLocEntries;
563 /// \brief Emit an entry for the debug loc section. This can be used to
564 /// handle an entry that's going to be emitted into the debug loc section.
565 void emitDebugLocEntry(ByteStreamer &Streamer, const DebugLocEntry &Entry);
566 /// \brief emit a single value for the debug loc section.
567 void emitDebugLocValue(ByteStreamer &Streamer,
568 const DebugLocEntry::Value &Value);
569 /// Emits an optimal (=sorted) sequence of DW_OP_pieces.
570 void emitLocPieces(ByteStreamer &Streamer,
571 const DITypeIdentifierMap &Map,
572 ArrayRef<DebugLocEntry::Value> Values);
574 /// Emit the location for a debug loc entry, including the size header.
575 void emitDebugLocEntryLocation(const DebugLocEntry &Entry);
577 /// Find the MDNode for the given reference.
578 template <typename T> T resolve(DIRef<T> Ref) const {
579 return Ref.resolve(TypeIdentifierMap);
582 /// \brief Return the TypeIdentifierMap.
583 const DITypeIdentifierMap &getTypeIdentifierMap() const {
584 return TypeIdentifierMap;
587 /// Find the DwarfCompileUnit for the given CU Die.
588 DwarfCompileUnit *lookupUnit(const DIE *CU) const {
589 return CUDieMap.lookup(CU);
591 /// isSubprogramContext - Return true if Context is either a subprogram
592 /// or another context nested inside a subprogram.
593 bool isSubprogramContext(const MDNode *Context);
595 void addSubprogramNames(DISubprogram SP, DIE &Die);
597 AddressPool &getAddressPool() { return AddrPool; }
599 void addAccelName(StringRef Name, const DIE &Die);
601 void addAccelObjC(StringRef Name, const DIE &Die);
603 void addAccelNamespace(StringRef Name, const DIE &Die);
605 void addAccelType(StringRef Name, const DIE &Die, char Flags);
607 const MachineFunction *getCurrentFunction() const { return CurFn; }
608 const MCSymbol *getFunctionBeginSym() const { return FunctionBeginSym; }
609 const MCSymbol *getFunctionEndSym() const { return FunctionEndSym; }
611 iterator_range<ImportedEntityMap::const_iterator>
612 findImportedEntitiesForScope(const MDNode *Scope) const {
613 return make_range(std::equal_range(
614 ScopesWithImportedEntities.begin(), ScopesWithImportedEntities.end(),
615 std::pair<const MDNode *, const MDNode *>(Scope, nullptr),
619 /// \brief A helper function to check whether the DIE for a given Scope is
620 /// going to be null.
621 bool isLexicalScopeDIENull(LexicalScope *Scope);
623 /// \brief Return Label preceding the instruction.
624 MCSymbol *getLabelBeforeInsn(const MachineInstr *MI);
626 /// \brief Return Label immediately following the instruction.
627 MCSymbol *getLabelAfterInsn(const MachineInstr *MI);
629 // FIXME: Consider rolling ranges up into DwarfDebug since we use a single
630 // range_base anyway, so there's no need to keep them as separate per-CU range
631 // lists. (though one day we might end up with a range.dwo section, in which
632 // case it'd go to DwarfFile)
633 unsigned getNextRangeNumber() { return GlobalRangeCount++; }
635 // FIXME: Sink these functions down into DwarfFile/Dwarf*Unit.
637 SmallPtrSet<const MDNode *, 16> &getProcessedSPNodes() {
638 return ProcessedSPNodes;
641 } // End of namespace llvm