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 "AsmPrinterHandler.h"
18 #include "DbgValueHistoryCalculator.h"
19 #include "DebugLocStream.h"
20 #include "DwarfAccelTable.h"
21 #include "DwarfFile.h"
22 #include "llvm/ADT/DenseMap.h"
23 #include "llvm/ADT/DenseSet.h"
24 #include "llvm/ADT/FoldingSet.h"
25 #include "llvm/ADT/MapVector.h"
26 #include "llvm/ADT/SmallPtrSet.h"
27 #include "llvm/ADT/StringMap.h"
28 #include "llvm/CodeGen/DIE.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/MCDwarf.h"
34 #include "llvm/MC/MachineLocation.h"
35 #include "llvm/Support/Allocator.h"
45 class DwarfCompileUnit;
49 class MachineModuleInfo;
51 //===----------------------------------------------------------------------===//
52 /// 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 /// This class is used to track local variable information.
72 /// Variables can be created from allocas, in which case they're generated from
73 /// the MMI table. Such variables can have multiple expressions and frame
74 /// indices. The \a Expr and \a FrameIndices array must match.
76 /// Variables can be created from \c DBG_VALUE instructions. Those whose
77 /// location changes over time use \a DebugLocListIndex, while those with a
78 /// single instruction use \a MInsn and (optionally) a single entry of \a Expr.
80 /// Variables that have been optimized out use none of these fields.
82 const DILocalVariable *Var; /// Variable Descriptor.
83 const DILocation *IA; /// Inlined at location.
84 SmallVector<const DIExpression *, 1> Expr; /// Complex address.
85 DIE *TheDIE = nullptr; /// Variable DIE.
86 unsigned DebugLocListIndex = ~0u; /// Offset in DebugLocs.
87 const MachineInstr *MInsn = nullptr; /// DBG_VALUE instruction.
88 SmallVector<int, 1> FrameIndex; /// Frame index.
92 /// Construct a DbgVariable.
94 /// Creates a variable without any DW_AT_location. Call \a initializeMMI()
95 /// for MMI entries, or \a initializeDbgValue() for DBG_VALUE instructions.
96 DbgVariable(const DILocalVariable *V, const DILocation *IA, DwarfDebug *DD)
97 : Var(V), IA(IA), DD(DD) {}
99 /// Initialize from the MMI table.
100 void initializeMMI(const DIExpression *E, int FI) {
101 assert(Expr.empty() && "Already initialized?");
102 assert(FrameIndex.empty() && "Already initialized?");
103 assert(!MInsn && "Already initialized?");
105 assert((!E || E->isValid()) && "Expected valid expression");
106 assert(~FI && "Expected valid index");
109 FrameIndex.push_back(FI);
112 /// Initialize from a DBG_VALUE instruction.
113 void initializeDbgValue(const MachineInstr *DbgValue) {
114 assert(Expr.empty() && "Already initialized?");
115 assert(FrameIndex.empty() && "Already initialized?");
116 assert(!MInsn && "Already initialized?");
118 assert(Var == DbgValue->getDebugVariable() && "Wrong variable");
119 assert(IA == DbgValue->getDebugLoc()->getInlinedAt() && "Wrong inlined-at");
122 if (auto *E = DbgValue->getDebugExpression())
123 if (E->getNumElements())
128 const DILocalVariable *getVariable() const { return Var; }
129 const DILocation *getInlinedAt() const { return IA; }
130 const ArrayRef<const DIExpression *> getExpression() const { return Expr; }
131 void setDIE(DIE &D) { TheDIE = &D; }
132 DIE *getDIE() const { return TheDIE; }
133 void setDebugLocListIndex(unsigned O) { DebugLocListIndex = O; }
134 unsigned getDebugLocListIndex() const { return DebugLocListIndex; }
135 StringRef getName() const { return Var->getName(); }
136 const MachineInstr *getMInsn() const { return MInsn; }
137 const ArrayRef<int> getFrameIndex() const { return FrameIndex; }
139 void addMMIEntry(const DbgVariable &V) {
140 assert(DebugLocListIndex == ~0U && !MInsn && "not an MMI entry");
141 assert(V.DebugLocListIndex == ~0U && !V.MInsn && "not an MMI entry");
142 assert(V.Var == Var && "conflicting variable");
143 assert(V.IA == IA && "conflicting inlined-at location");
145 assert(!FrameIndex.empty() && "Expected an MMI entry");
146 assert(!V.FrameIndex.empty() && "Expected an MMI entry");
147 assert(Expr.size() == FrameIndex.size() && "Mismatched expressions");
148 assert(V.Expr.size() == V.FrameIndex.size() && "Mismatched expressions");
150 Expr.append(V.Expr.begin(), V.Expr.end());
151 FrameIndex.append(V.FrameIndex.begin(), V.FrameIndex.end());
152 assert(std::all_of(Expr.begin(), Expr.end(), [](const DIExpression *E) {
153 return E && E->isBitPiece();
154 }) && "conflicting locations for variable");
157 // Translate tag to proper Dwarf tag.
158 dwarf::Tag getTag() const {
159 if (Var->getTag() == dwarf::DW_TAG_arg_variable)
160 return dwarf::DW_TAG_formal_parameter;
162 return dwarf::DW_TAG_variable;
164 /// Return true if DbgVariable is artificial.
165 bool isArtificial() const {
166 if (Var->isArtificial())
168 if (getType()->isArtificial())
173 bool isObjectPointer() const {
174 if (Var->isObjectPointer())
176 if (getType()->isObjectPointer())
181 bool hasComplexAddress() const {
182 assert(MInsn && "Expected DBG_VALUE, not MMI variable");
183 assert(FrameIndex.empty() && "Expected DBG_VALUE, not MMI variable");
185 (Expr.empty() || (Expr.size() == 1 && Expr.back()->getNumElements())) &&
186 "Invalid Expr for DBG_VALUE");
187 return !Expr.empty();
189 bool isBlockByrefVariable() const;
190 const DIType *getType() const;
193 /// Look in the DwarfDebug map for the MDNode that
194 /// corresponds to the reference.
195 template <typename T> T *resolve(TypedDINodeRef<T> Ref) const;
199 /// Helper used to pair up a symbol and its DWARF compile unit.
201 SymbolCU(DwarfCompileUnit *CU, const MCSymbol *Sym) : Sym(Sym), CU(CU) {}
203 DwarfCompileUnit *CU;
206 /// Collects and handles dwarf debug information.
207 class DwarfDebug : public AsmPrinterHandler {
208 /// Target of Dwarf emission.
211 /// Collected machine module information.
212 MachineModuleInfo *MMI;
214 /// All DIEValues are allocated through this allocator.
215 BumpPtrAllocator DIEValueAllocator;
217 /// Maps MDNode with its corresponding DwarfCompileUnit.
218 MapVector<const MDNode *, DwarfCompileUnit *> CUMap;
220 /// Maps subprogram MDNode with its corresponding DwarfCompileUnit.
221 MapVector<const MDNode *, DwarfCompileUnit *> SPMap;
223 /// Maps a CU DIE with its corresponding DwarfCompileUnit.
224 DenseMap<const DIE *, DwarfCompileUnit *> CUDieMap;
226 /// List of all labels used in aranges generation.
227 std::vector<SymbolCU> ArangeLabels;
229 /// Size of each symbol emitted (for those symbols that have a specific size).
230 DenseMap<const MCSymbol *, uint64_t> SymSize;
232 LexicalScopes LScopes;
234 /// Collection of abstract variables.
235 DenseMap<const MDNode *, std::unique_ptr<DbgVariable>> AbstractVariables;
236 SmallVector<std::unique_ptr<DbgVariable>, 64> ConcreteVariables;
238 /// Collection of DebugLocEntry. Stored in a linked list so that DIELocLists
239 /// can refer to them in spite of insertions into this list.
240 DebugLocStream DebugLocs;
242 /// This is a collection of subprogram MDNodes that are processed to
244 SmallPtrSet<const MDNode *, 16> ProcessedSPNodes;
246 /// Maps instruction with label emitted before instruction.
247 DenseMap<const MachineInstr *, MCSymbol *> LabelsBeforeInsn;
249 /// Maps instruction with label emitted after instruction.
250 DenseMap<const MachineInstr *, MCSymbol *> LabelsAfterInsn;
252 /// History of DBG_VALUE and clobber instructions for each user
253 /// variable. Variables are listed in order of appearance.
254 DbgValueHistoryMap DbgValues;
256 /// Previous instruction's location information. This is used to
257 /// determine label location to indicate scope boundries in dwarf
259 DebugLoc PrevInstLoc;
262 /// This location indicates end of function prologue and beginning of
264 DebugLoc PrologEndLoc;
266 /// If nonnull, stores the current machine function we're processing.
267 const MachineFunction *CurFn;
269 /// If nonnull, stores the current machine instruction we're processing.
270 const MachineInstr *CurMI;
272 /// If nonnull, stores the CU in which the previous subprogram was contained.
273 const DwarfCompileUnit *PrevCU;
275 /// As an optimization, there is no need to emit an entry in the directory
276 /// table for the same directory as DW_AT_comp_dir.
277 StringRef CompilationDir;
279 /// Holder for the file specific debug information.
280 DwarfFile InfoHolder;
282 /// Holders for the various debug information flags that we might need to
283 /// have exposed. See accessor functions below for description.
285 /// Holder for imported entities.
286 typedef SmallVector<std::pair<const MDNode *, const MDNode *>, 32>
288 ImportedEntityMap ScopesWithImportedEntities;
290 /// Map from MDNodes for user-defined types to the type units that
292 DenseMap<const MDNode *, const DwarfTypeUnit *> DwarfTypeUnits;
295 std::pair<std::unique_ptr<DwarfTypeUnit>, const DICompositeType *>, 1>
296 TypeUnitsUnderConstruction;
298 /// Whether to emit the pubnames/pubtypes sections.
299 bool HasDwarfPubSections;
301 /// Whether or not to use AT_ranges for compilation units.
304 /// Whether we emitted a function into a section other than the
306 bool UsedNonDefaultText;
308 /// Whether to use the GNU TLS opcode (instead of the standard opcode).
309 bool UseGNUTLSOpcode;
311 /// Version of dwarf we're emitting.
312 unsigned DwarfVersion;
314 /// Maps from a type identifier to the actual MDNode.
315 DITypeIdentifierMap TypeIdentifierMap;
317 /// DWARF5 Experimental Options
319 bool HasDwarfAccelTables;
322 /// Separated Dwarf Variables
323 /// In general these will all be for bits that are left in the
324 /// original object file, rather than things that are meant
325 /// to be in the .dwo sections.
327 /// Holder for the skeleton information.
328 DwarfFile SkeletonHolder;
330 /// Store file names for type units under fission in a line table
331 /// header that will be emitted into debug_line.dwo.
332 // FIXME: replace this with a map from comp_dir to table so that we
333 // can emit multiple tables during LTO each of which uses directory
334 // 0, referencing the comp_dir of all the type units that use it.
335 MCDwarfDwoLineTable SplitTypeUnitFileTable;
338 /// True iff there are multiple CUs in this module.
343 AddressPool AddrPool;
345 DwarfAccelTable AccelNames;
346 DwarfAccelTable AccelObjC;
347 DwarfAccelTable AccelNamespace;
348 DwarfAccelTable AccelTypes;
350 DenseMap<const Function *, DISubprogram *> FunctionDIs;
352 MCDwarfDwoLineTable *getDwoLineTable(const DwarfCompileUnit &);
354 const SmallVectorImpl<std::unique_ptr<DwarfUnit>> &getUnits() {
355 return InfoHolder.getUnits();
358 typedef DbgValueHistoryMap::InlinedVariable InlinedVariable;
360 /// Find abstract variable associated with Var.
361 DbgVariable *getExistingAbstractVariable(InlinedVariable IV,
362 const DILocalVariable *&Cleansed);
363 DbgVariable *getExistingAbstractVariable(InlinedVariable IV);
364 void createAbstractVariable(const DILocalVariable *DV, LexicalScope *Scope);
365 void ensureAbstractVariableIsCreated(InlinedVariable Var,
366 const MDNode *Scope);
367 void ensureAbstractVariableIsCreatedIfScoped(InlinedVariable Var,
368 const MDNode *Scope);
370 DbgVariable *createConcreteVariable(LexicalScope &Scope, InlinedVariable IV);
372 /// Construct a DIE for this abstract scope.
373 void constructAbstractSubprogramScopeDIE(LexicalScope *Scope);
375 /// Compute the size and offset of a DIE given an incoming Offset.
376 unsigned computeSizeAndOffset(DIE *Die, unsigned Offset);
378 /// Compute the size and offset of all the DIEs.
379 void computeSizeAndOffsets();
381 /// Collect info for variables that were optimized out.
382 void collectDeadVariables();
384 void finishVariableDefinitions();
386 void finishSubprogramDefinitions();
388 /// Finish off debug information after all functions have been
390 void finalizeModuleInfo();
392 /// Emit the debug info section.
393 void emitDebugInfo();
395 /// Emit the abbreviation section.
396 void emitAbbreviations();
398 /// Emit a specified accelerator table.
399 void emitAccel(DwarfAccelTable &Accel, MCSection *Section,
400 StringRef TableName);
402 /// Emit visible names into a hashed accelerator table section.
403 void emitAccelNames();
405 /// Emit objective C classes and categories into a hashed
406 /// accelerator table section.
407 void emitAccelObjC();
409 /// Emit namespace dies into a hashed accelerator table.
410 void emitAccelNamespaces();
412 /// Emit type dies into a hashed accelerator table.
413 void emitAccelTypes();
415 /// Emit visible names into a debug pubnames section.
416 /// \param GnuStyle determines whether or not we want to emit
417 /// additional information into the table ala newer gcc for gdb
419 void emitDebugPubNames(bool GnuStyle = false);
421 /// Emit visible types into a debug pubtypes section.
422 /// \param GnuStyle determines whether or not we want to emit
423 /// additional information into the table ala newer gcc for gdb
425 void emitDebugPubTypes(bool GnuStyle = false);
427 void emitDebugPubSection(
428 bool GnuStyle, MCSection *PSec, StringRef Name,
429 const StringMap<const DIE *> &(DwarfCompileUnit::*Accessor)() const);
431 /// Emit visible names into a debug str section.
434 /// Emit visible names into a debug loc section.
437 /// Emit visible names into a debug loc dwo section.
438 void emitDebugLocDWO();
440 /// Emit visible names into a debug aranges section.
441 void emitDebugARanges();
443 /// Emit visible names into a debug ranges section.
444 void emitDebugRanges();
446 /// Emit inline info using custom format.
447 void emitDebugInlineInfo();
449 /// DWARF 5 Experimental Split Dwarf Emitters
451 /// Initialize common features of skeleton units.
452 void initSkeletonUnit(const DwarfUnit &U, DIE &Die,
453 std::unique_ptr<DwarfUnit> NewU);
455 /// Construct the split debug info compile unit for the debug info
457 DwarfCompileUnit &constructSkeletonCU(const DwarfCompileUnit &CU);
459 /// Construct the split debug info compile unit for the debug info
461 DwarfTypeUnit &constructSkeletonTU(DwarfTypeUnit &TU);
463 /// Emit the debug info dwo section.
464 void emitDebugInfoDWO();
466 /// Emit the debug abbrev dwo section.
467 void emitDebugAbbrevDWO();
469 /// Emit the debug line dwo section.
470 void emitDebugLineDWO();
472 /// Emit the debug str dwo section.
473 void emitDebugStrDWO();
475 /// Flags to let the linker know we have emitted new style pubnames. Only
476 /// emit it here if we don't have a skeleton CU for split dwarf.
477 void addGnuPubAttributes(DwarfUnit &U, DIE &D) const;
479 /// Create new DwarfCompileUnit for the given metadata node with tag
480 /// DW_TAG_compile_unit.
481 DwarfCompileUnit &constructDwarfCompileUnit(const DICompileUnit *DIUnit);
483 /// Construct imported_module or imported_declaration DIE.
484 void constructAndAddImportedEntityDIE(DwarfCompileUnit &TheCU,
485 const DIImportedEntity *N);
487 /// Register a source line with debug info. Returns the unique
488 /// label that was emitted and which provides correspondence to the
489 /// source line list.
490 void recordSourceLine(unsigned Line, unsigned Col, const MDNode *Scope,
493 /// Indentify instructions that are marking the beginning of or
494 /// ending of a scope.
495 void identifyScopeMarkers();
497 /// Populate LexicalScope entries with variables' info.
498 void collectVariableInfo(DwarfCompileUnit &TheCU, const DISubprogram *SP,
499 DenseSet<InlinedVariable> &ProcessedVars);
501 /// Build the location list for all DBG_VALUEs in the
502 /// function that describe the same variable.
503 void buildLocationList(SmallVectorImpl<DebugLocEntry> &DebugLoc,
504 const DbgValueHistoryMap::InstrRanges &Ranges);
506 /// Collect variable information from the side table maintained
508 void collectVariableInfoFromMMITable(DenseSet<InlinedVariable> &P);
510 /// Ensure that a label will be emitted before MI.
511 void requestLabelBeforeInsn(const MachineInstr *MI) {
512 LabelsBeforeInsn.insert(std::make_pair(MI, nullptr));
515 /// Ensure that a label will be emitted after MI.
516 void requestLabelAfterInsn(const MachineInstr *MI) {
517 LabelsAfterInsn.insert(std::make_pair(MI, nullptr));
521 //===--------------------------------------------------------------------===//
522 // Main entry points.
524 DwarfDebug(AsmPrinter *A, Module *M);
526 ~DwarfDebug() override;
528 /// Emit all Dwarf sections that should come prior to the
532 /// Emit all Dwarf sections that should come after the content.
533 void endModule() override;
535 /// Gather pre-function debug information.
536 void beginFunction(const MachineFunction *MF) override;
538 /// Gather and emit post-function debug information.
539 void endFunction(const MachineFunction *MF) override;
541 /// Process beginning of an instruction.
542 void beginInstruction(const MachineInstr *MI) override;
544 /// Process end of an instruction.
545 void endInstruction() override;
547 /// Add a DIE to the set of types that we're going to pull into
549 void addDwarfTypeUnitType(DwarfCompileUnit &CU, StringRef Identifier,
550 DIE &Die, const DICompositeType *CTy);
552 /// Add a label so that arange data can be generated for it.
553 void addArangeLabel(SymbolCU SCU) { ArangeLabels.push_back(SCU); }
555 /// For symbols that have a size designated (e.g. common symbols),
556 /// this tracks that size.
557 void setSymbolSize(const MCSymbol *Sym, uint64_t Size) override {
561 /// Returns whether to use DW_OP_GNU_push_tls_address, instead of the
562 /// standard DW_OP_form_tls_address opcode
563 bool useGNUTLSOpcode() const { return UseGNUTLSOpcode; }
565 // Experimental DWARF5 features.
567 /// Returns whether or not to emit tables that dwarf consumers can
568 /// use to accelerate lookup.
569 bool useDwarfAccelTables() const { return HasDwarfAccelTables; }
571 /// Returns whether or not to change the current debug info for the
572 /// split dwarf proposal support.
573 bool useSplitDwarf() const { return HasSplitDwarf; }
575 /// Returns the Dwarf Version.
576 unsigned getDwarfVersion() const { return DwarfVersion; }
578 /// Returns the previous CU that was being updated
579 const DwarfCompileUnit *getPrevCU() const { return PrevCU; }
580 void setPrevCU(const DwarfCompileUnit *PrevCU) { this->PrevCU = PrevCU; }
582 /// Returns the entries for the .debug_loc section.
583 const DebugLocStream &getDebugLocs() const { return DebugLocs; }
585 /// Emit an entry for the debug loc section. This can be used to
586 /// handle an entry that's going to be emitted into the debug loc section.
587 void emitDebugLocEntry(ByteStreamer &Streamer,
588 const DebugLocStream::Entry &Entry);
590 /// Emit the location for a debug loc entry, including the size header.
591 void emitDebugLocEntryLocation(const DebugLocStream::Entry &Entry);
593 /// Find the MDNode for the given reference.
594 template <typename T> T *resolve(TypedDINodeRef<T> Ref) const {
595 return Ref.resolve(TypeIdentifierMap);
598 /// 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(const 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; }
625 iterator_range<ImportedEntityMap::const_iterator>
626 findImportedEntitiesForScope(const MDNode *Scope) const {
627 return make_range(std::equal_range(
628 ScopesWithImportedEntities.begin(), ScopesWithImportedEntities.end(),
629 std::pair<const MDNode *, const MDNode *>(Scope, nullptr),
633 /// A helper function to check whether the DIE for a given Scope is
634 /// going to be null.
635 bool isLexicalScopeDIENull(LexicalScope *Scope);
637 /// Return Label preceding the instruction.
638 MCSymbol *getLabelBeforeInsn(const MachineInstr *MI);
640 /// Return Label immediately following the instruction.
641 MCSymbol *getLabelAfterInsn(const MachineInstr *MI);
643 // FIXME: Sink these functions down into DwarfFile/Dwarf*Unit.
645 SmallPtrSet<const MDNode *, 16> &getProcessedSPNodes() {
646 return ProcessedSPNodes;
649 } // End of namespace llvm