1 //===--- CGDebugInfo.h - DebugInfo for LLVM CodeGen -------------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This is the source-level debug info generator for llvm translation.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #ifndef LLVM_CLANG_LIB_CODEGEN_CGDEBUGINFO_H
14 #define LLVM_CLANG_LIB_CODEGEN_CGDEBUGINFO_H
15 
16 #include "CGBuilder.h"
17 #include "clang/AST/DeclCXX.h"
18 #include "clang/AST/Expr.h"
19 #include "clang/AST/ExternalASTSource.h"
20 #include "clang/AST/PrettyPrinter.h"
21 #include "clang/AST/Type.h"
22 #include "clang/AST/TypeOrdering.h"
23 #include "clang/Basic/CodeGenOptions.h"
24 #include "clang/Basic/Module.h"
25 #include "clang/Basic/SourceLocation.h"
26 #include "llvm/ADT/DenseMap.h"
27 #include "llvm/ADT/DenseSet.h"
28 #include "llvm/ADT/Optional.h"
29 #include "llvm/IR/DIBuilder.h"
30 #include "llvm/IR/DebugInfo.h"
31 #include "llvm/IR/ValueHandle.h"
32 #include "llvm/Support/Allocator.h"
33 
34 namespace llvm {
35 class MDNode;
36 }
37 
38 namespace clang {
39 class ClassTemplateSpecializationDecl;
40 class GlobalDecl;
41 class ModuleMap;
42 class ObjCInterfaceDecl;
43 class ObjCIvarDecl;
44 class UsingDecl;
45 class VarDecl;
46 enum class DynamicInitKind : unsigned;
47 
48 namespace CodeGen {
49 class CodeGenModule;
50 class CodeGenFunction;
51 class CGBlockInfo;
52 
53 /// This class gathers all debug information during compilation and is
54 /// responsible for emitting to llvm globals or pass directly to the
55 /// backend.
56 class CGDebugInfo {
57   friend class ApplyDebugLocation;
58   friend class SaveAndRestoreLocation;
59   CodeGenModule &CGM;
60   const codegenoptions::DebugInfoKind DebugKind;
61   bool DebugTypeExtRefs;
62   llvm::DIBuilder DBuilder;
63   llvm::DICompileUnit *TheCU = nullptr;
64   ModuleMap *ClangModuleMap = nullptr;
65   ASTSourceDescriptor PCHDescriptor;
66   SourceLocation CurLoc;
67   llvm::MDNode *CurInlinedAt = nullptr;
68   llvm::DIType *VTablePtrType = nullptr;
69   llvm::DIType *ClassTy = nullptr;
70   llvm::DICompositeType *ObjTy = nullptr;
71   llvm::DIType *SelTy = nullptr;
72 #define IMAGE_TYPE(ImgType, Id, SingletonId, Access, Suffix)                   \
73   llvm::DIType *SingletonId = nullptr;
74 #include "clang/Basic/OpenCLImageTypes.def"
75   llvm::DIType *OCLSamplerDITy = nullptr;
76   llvm::DIType *OCLEventDITy = nullptr;
77   llvm::DIType *OCLClkEventDITy = nullptr;
78   llvm::DIType *OCLQueueDITy = nullptr;
79   llvm::DIType *OCLNDRangeDITy = nullptr;
80   llvm::DIType *OCLReserveIDDITy = nullptr;
81 #define EXT_OPAQUE_TYPE(ExtType, Id, Ext) \
82   llvm::DIType *Id##Ty = nullptr;
83 #include "clang/Basic/OpenCLExtensionTypes.def"
84 
85   /// Cache of previously constructed Types.
86   llvm::DenseMap<const void *, llvm::TrackingMDRef> TypeCache;
87 
88   std::map<llvm::StringRef, llvm::StringRef, std::greater<llvm::StringRef>>
89       DebugPrefixMap;
90 
91   /// Cache that maps VLA types to size expressions for that type,
92   /// represented by instantiated Metadata nodes.
93   llvm::SmallDenseMap<QualType, llvm::Metadata *> SizeExprCache;
94 
95   /// Callbacks to use when printing names and types.
96   class PrintingCallbacks final : public clang::PrintingCallbacks {
97     const CGDebugInfo &Self;
98 
99   public:
100     PrintingCallbacks(const CGDebugInfo &Self) : Self(Self) {}
101     std::string remapPath(StringRef Path) const override {
102       return Self.remapDIPath(Path);
103     }
104   };
105   PrintingCallbacks PrintCB = {*this};
106 
107   struct ObjCInterfaceCacheEntry {
108     const ObjCInterfaceType *Type;
109     llvm::DIType *Decl;
110     llvm::DIFile *Unit;
111     ObjCInterfaceCacheEntry(const ObjCInterfaceType *Type, llvm::DIType *Decl,
112                             llvm::DIFile *Unit)
113         : Type(Type), Decl(Decl), Unit(Unit) {}
114   };
115 
116   /// Cache of previously constructed interfaces which may change.
117   llvm::SmallVector<ObjCInterfaceCacheEntry, 32> ObjCInterfaceCache;
118 
119   /// Cache of forward declarations for methods belonging to the interface.
120   /// The extra bit on the DISubprogram specifies whether a method is
121   /// "objc_direct".
122   llvm::DenseMap<const ObjCInterfaceDecl *,
123                  std::vector<llvm::PointerIntPair<llvm::DISubprogram *, 1>>>
124       ObjCMethodCache;
125 
126   /// Cache of references to clang modules and precompiled headers.
127   llvm::DenseMap<const Module *, llvm::TrackingMDRef> ModuleCache;
128 
129   /// List of interfaces we want to keep even if orphaned.
130   std::vector<void *> RetainedTypes;
131 
132   /// Cache of forward declared types to RAUW at the end of compilation.
133   std::vector<std::pair<const TagType *, llvm::TrackingMDRef>> ReplaceMap;
134 
135   /// Cache of replaceable forward declarations (functions and
136   /// variables) to RAUW at the end of compilation.
137   std::vector<std::pair<const DeclaratorDecl *, llvm::TrackingMDRef>>
138       FwdDeclReplaceMap;
139 
140   /// Keep track of our current nested lexical block.
141   std::vector<llvm::TypedTrackingMDRef<llvm::DIScope>> LexicalBlockStack;
142   llvm::DenseMap<const Decl *, llvm::TrackingMDRef> RegionMap;
143   /// Keep track of LexicalBlockStack counter at the beginning of a
144   /// function. This is used to pop unbalanced regions at the end of a
145   /// function.
146   std::vector<unsigned> FnBeginRegionCount;
147 
148   /// This is a storage for names that are constructed on demand. For
149   /// example, C++ destructors, C++ operators etc..
150   llvm::BumpPtrAllocator DebugInfoNames;
151   StringRef CWDName;
152 
153   llvm::DenseMap<const char *, llvm::TrackingMDRef> DIFileCache;
154   llvm::DenseMap<const FunctionDecl *, llvm::TrackingMDRef> SPCache;
155   /// Cache declarations relevant to DW_TAG_imported_declarations (C++
156   /// using declarations) that aren't covered by other more specific caches.
157   llvm::DenseMap<const Decl *, llvm::TrackingMDRef> DeclCache;
158   llvm::DenseMap<const NamespaceDecl *, llvm::TrackingMDRef> NamespaceCache;
159   llvm::DenseMap<const NamespaceAliasDecl *, llvm::TrackingMDRef>
160       NamespaceAliasCache;
161   llvm::DenseMap<const Decl *, llvm::TypedTrackingMDRef<llvm::DIDerivedType>>
162       StaticDataMemberCache;
163 
164   /// Helper functions for getOrCreateType.
165   /// @{
166   /// Currently the checksum of an interface includes the number of
167   /// ivars and property accessors.
168   llvm::DIType *CreateType(const BuiltinType *Ty);
169   llvm::DIType *CreateType(const ComplexType *Ty);
170   llvm::DIType *CreateType(const AutoType *Ty);
171   llvm::DIType *CreateType(const ExtIntType *Ty);
172   llvm::DIType *CreateQualifiedType(QualType Ty, llvm::DIFile *Fg);
173   llvm::DIType *CreateType(const TypedefType *Ty, llvm::DIFile *Fg);
174   llvm::DIType *CreateType(const TemplateSpecializationType *Ty,
175                            llvm::DIFile *Fg);
176   llvm::DIType *CreateType(const ObjCObjectPointerType *Ty, llvm::DIFile *F);
177   llvm::DIType *CreateType(const PointerType *Ty, llvm::DIFile *F);
178   llvm::DIType *CreateType(const BlockPointerType *Ty, llvm::DIFile *F);
179   llvm::DIType *CreateType(const FunctionType *Ty, llvm::DIFile *F);
180   /// Get structure or union type.
181   llvm::DIType *CreateType(const RecordType *Tyg);
182   llvm::DIType *CreateTypeDefinition(const RecordType *Ty);
183   llvm::DICompositeType *CreateLimitedType(const RecordType *Ty);
184   void CollectContainingType(const CXXRecordDecl *RD,
185                              llvm::DICompositeType *CT);
186   /// Get Objective-C interface type.
187   llvm::DIType *CreateType(const ObjCInterfaceType *Ty, llvm::DIFile *F);
188   llvm::DIType *CreateTypeDefinition(const ObjCInterfaceType *Ty,
189                                      llvm::DIFile *F);
190   /// Get Objective-C object type.
191   llvm::DIType *CreateType(const ObjCObjectType *Ty, llvm::DIFile *F);
192   llvm::DIType *CreateType(const ObjCTypeParamType *Ty, llvm::DIFile *Unit);
193 
194   llvm::DIType *CreateType(const VectorType *Ty, llvm::DIFile *F);
195   llvm::DIType *CreateType(const ConstantMatrixType *Ty, llvm::DIFile *F);
196   llvm::DIType *CreateType(const ArrayType *Ty, llvm::DIFile *F);
197   llvm::DIType *CreateType(const LValueReferenceType *Ty, llvm::DIFile *F);
198   llvm::DIType *CreateType(const RValueReferenceType *Ty, llvm::DIFile *Unit);
199   llvm::DIType *CreateType(const MemberPointerType *Ty, llvm::DIFile *F);
200   llvm::DIType *CreateType(const AtomicType *Ty, llvm::DIFile *F);
201   llvm::DIType *CreateType(const PipeType *Ty, llvm::DIFile *F);
202   /// Get enumeration type.
203   llvm::DIType *CreateEnumType(const EnumType *Ty);
204   llvm::DIType *CreateTypeDefinition(const EnumType *Ty);
205   /// Look up the completed type for a self pointer in the TypeCache and
206   /// create a copy of it with the ObjectPointer and Artificial flags
207   /// set. If the type is not cached, a new one is created. This should
208   /// never happen though, since creating a type for the implicit self
209   /// argument implies that we already parsed the interface definition
210   /// and the ivar declarations in the implementation.
211   llvm::DIType *CreateSelfType(const QualType &QualTy, llvm::DIType *Ty);
212   /// @}
213 
214   /// Get the type from the cache or return null type if it doesn't
215   /// exist.
216   llvm::DIType *getTypeOrNull(const QualType);
217   /// Return the debug type for a C++ method.
218   /// \arg CXXMethodDecl is of FunctionType. This function type is
219   /// not updated to include implicit \c this pointer. Use this routine
220   /// to get a method type which includes \c this pointer.
221   llvm::DISubroutineType *getOrCreateMethodType(const CXXMethodDecl *Method,
222                                                 llvm::DIFile *F, bool decl);
223   llvm::DISubroutineType *
224   getOrCreateInstanceMethodType(QualType ThisPtr, const FunctionProtoType *Func,
225                                 llvm::DIFile *Unit, bool decl);
226   llvm::DISubroutineType *
227   getOrCreateFunctionType(const Decl *D, QualType FnType, llvm::DIFile *F);
228   /// \return debug info descriptor for vtable.
229   llvm::DIType *getOrCreateVTablePtrType(llvm::DIFile *F);
230 
231   /// \return namespace descriptor for the given namespace decl.
232   llvm::DINamespace *getOrCreateNamespace(const NamespaceDecl *N);
233   llvm::DIType *CreatePointerLikeType(llvm::dwarf::Tag Tag, const Type *Ty,
234                                       QualType PointeeTy, llvm::DIFile *F);
235   llvm::DIType *getOrCreateStructPtrType(StringRef Name, llvm::DIType *&Cache);
236 
237   /// A helper function to create a subprogram for a single member
238   /// function GlobalDecl.
239   llvm::DISubprogram *CreateCXXMemberFunction(const CXXMethodDecl *Method,
240                                               llvm::DIFile *F,
241                                               llvm::DIType *RecordTy);
242 
243   /// A helper function to collect debug info for C++ member
244   /// functions. This is used while creating debug info entry for a
245   /// Record.
246   void CollectCXXMemberFunctions(const CXXRecordDecl *Decl, llvm::DIFile *F,
247                                  SmallVectorImpl<llvm::Metadata *> &E,
248                                  llvm::DIType *T);
249 
250   /// A helper function to collect debug info for C++ base
251   /// classes. This is used while creating debug info entry for a
252   /// Record.
253   void CollectCXXBases(const CXXRecordDecl *Decl, llvm::DIFile *F,
254                        SmallVectorImpl<llvm::Metadata *> &EltTys,
255                        llvm::DIType *RecordTy);
256 
257   /// Helper function for CollectCXXBases.
258   /// Adds debug info entries for types in Bases that are not in SeenTypes.
259   void CollectCXXBasesAux(
260       const CXXRecordDecl *RD, llvm::DIFile *Unit,
261       SmallVectorImpl<llvm::Metadata *> &EltTys, llvm::DIType *RecordTy,
262       const CXXRecordDecl::base_class_const_range &Bases,
263       llvm::DenseSet<CanonicalDeclPtr<const CXXRecordDecl>> &SeenTypes,
264       llvm::DINode::DIFlags StartingFlags);
265 
266   /// A helper function to collect template parameters.
267   llvm::DINodeArray CollectTemplateParams(const TemplateParameterList *TPList,
268                                           ArrayRef<TemplateArgument> TAList,
269                                           llvm::DIFile *Unit);
270   /// A helper function to collect debug info for function template
271   /// parameters.
272   llvm::DINodeArray CollectFunctionTemplateParams(const FunctionDecl *FD,
273                                                   llvm::DIFile *Unit);
274 
275   /// A helper function to collect debug info for function template
276   /// parameters.
277   llvm::DINodeArray CollectVarTemplateParams(const VarDecl *VD,
278                                              llvm::DIFile *Unit);
279 
280   /// A helper function to collect debug info for template
281   /// parameters.
282   llvm::DINodeArray
283   CollectCXXTemplateParams(const ClassTemplateSpecializationDecl *TS,
284                            llvm::DIFile *F);
285 
286   llvm::DIType *createFieldType(StringRef name, QualType type,
287                                 SourceLocation loc, AccessSpecifier AS,
288                                 uint64_t offsetInBits, uint32_t AlignInBits,
289                                 llvm::DIFile *tunit, llvm::DIScope *scope,
290                                 const RecordDecl *RD = nullptr);
291 
292   llvm::DIType *createFieldType(StringRef name, QualType type,
293                                 SourceLocation loc, AccessSpecifier AS,
294                                 uint64_t offsetInBits, llvm::DIFile *tunit,
295                                 llvm::DIScope *scope,
296                                 const RecordDecl *RD = nullptr) {
297     return createFieldType(name, type, loc, AS, offsetInBits, 0, tunit, scope,
298                            RD);
299   }
300 
301   /// Create new bit field member.
302   llvm::DIType *createBitFieldType(const FieldDecl *BitFieldDecl,
303                                    llvm::DIScope *RecordTy,
304                                    const RecordDecl *RD);
305 
306   /// Helpers for collecting fields of a record.
307   /// @{
308   void CollectRecordLambdaFields(const CXXRecordDecl *CXXDecl,
309                                  SmallVectorImpl<llvm::Metadata *> &E,
310                                  llvm::DIType *RecordTy);
311   llvm::DIDerivedType *CreateRecordStaticField(const VarDecl *Var,
312                                                llvm::DIType *RecordTy,
313                                                const RecordDecl *RD);
314   void CollectRecordNormalField(const FieldDecl *Field, uint64_t OffsetInBits,
315                                 llvm::DIFile *F,
316                                 SmallVectorImpl<llvm::Metadata *> &E,
317                                 llvm::DIType *RecordTy, const RecordDecl *RD);
318   void CollectRecordNestedType(const TypeDecl *RD,
319                                SmallVectorImpl<llvm::Metadata *> &E);
320   void CollectRecordFields(const RecordDecl *Decl, llvm::DIFile *F,
321                            SmallVectorImpl<llvm::Metadata *> &E,
322                            llvm::DICompositeType *RecordTy);
323 
324   /// If the C++ class has vtable info then insert appropriate debug
325   /// info entry in EltTys vector.
326   void CollectVTableInfo(const CXXRecordDecl *Decl, llvm::DIFile *F,
327                          SmallVectorImpl<llvm::Metadata *> &EltTys);
328   /// @}
329 
330   /// Create a new lexical block node and push it on the stack.
331   void CreateLexicalBlock(SourceLocation Loc);
332 
333   /// If target-specific LLVM \p AddressSpace directly maps to target-specific
334   /// DWARF address space, appends extended dereferencing mechanism to complex
335   /// expression \p Expr. Otherwise, does nothing.
336   ///
337   /// Extended dereferencing mechanism is has the following format:
338   ///     DW_OP_constu <DWARF Address Space> DW_OP_swap DW_OP_xderef
339   void AppendAddressSpaceXDeref(unsigned AddressSpace,
340                                 SmallVectorImpl<int64_t> &Expr) const;
341 
342   /// A helper function to collect debug info for the default elements of a
343   /// block.
344   ///
345   /// \returns The next available field offset after the default elements.
346   uint64_t collectDefaultElementTypesForBlockPointer(
347       const BlockPointerType *Ty, llvm::DIFile *Unit,
348       llvm::DIDerivedType *DescTy, unsigned LineNo,
349       SmallVectorImpl<llvm::Metadata *> &EltTys);
350 
351   /// A helper function to collect debug info for the default fields of a
352   /// block.
353   void collectDefaultFieldsForBlockLiteralDeclare(
354       const CGBlockInfo &Block, const ASTContext &Context, SourceLocation Loc,
355       const llvm::StructLayout &BlockLayout, llvm::DIFile *Unit,
356       SmallVectorImpl<llvm::Metadata *> &Fields);
357 
358 public:
359   CGDebugInfo(CodeGenModule &CGM);
360   ~CGDebugInfo();
361 
362   void finalize();
363 
364   /// Remap a given path with the current debug prefix map
365   std::string remapDIPath(StringRef) const;
366 
367   /// Register VLA size expression debug node with the qualified type.
368   void registerVLASizeExpression(QualType Ty, llvm::Metadata *SizeExpr) {
369     SizeExprCache[Ty] = SizeExpr;
370   }
371 
372   /// Module debugging: Support for building PCMs.
373   /// @{
374   /// Set the main CU's DwoId field to \p Signature.
375   void setDwoId(uint64_t Signature);
376 
377   /// When generating debug information for a clang module or
378   /// precompiled header, this module map will be used to determine
379   /// the module of origin of each Decl.
380   void setModuleMap(ModuleMap &MMap) { ClangModuleMap = &MMap; }
381 
382   /// When generating debug information for a clang module or
383   /// precompiled header, this module map will be used to determine
384   /// the module of origin of each Decl.
385   void setPCHDescriptor(ASTSourceDescriptor PCH) { PCHDescriptor = PCH; }
386   /// @}
387 
388   /// Update the current source location. If \arg loc is invalid it is
389   /// ignored.
390   void setLocation(SourceLocation Loc);
391 
392   /// Return the current source location. This does not necessarily correspond
393   /// to the IRBuilder's current DebugLoc.
394   SourceLocation getLocation() const { return CurLoc; }
395 
396   /// Update the current inline scope. All subsequent calls to \p EmitLocation
397   /// will create a location with this inlinedAt field.
398   void setInlinedAt(llvm::MDNode *InlinedAt) { CurInlinedAt = InlinedAt; }
399 
400   /// \return the current inline scope.
401   llvm::MDNode *getInlinedAt() const { return CurInlinedAt; }
402 
403   // Converts a SourceLocation to a DebugLoc
404   llvm::DebugLoc SourceLocToDebugLoc(SourceLocation Loc);
405 
406   /// Emit metadata to indicate a change in line/column information in
407   /// the source file. If the location is invalid, the previous
408   /// location will be reused.
409   void EmitLocation(CGBuilderTy &Builder, SourceLocation Loc);
410 
411   /// Emit a call to llvm.dbg.function.start to indicate
412   /// start of a new function.
413   /// \param Loc       The location of the function header.
414   /// \param ScopeLoc  The location of the function body.
415   void emitFunctionStart(GlobalDecl GD, SourceLocation Loc,
416                          SourceLocation ScopeLoc, QualType FnType,
417                          llvm::Function *Fn, bool CurFnIsThunk);
418 
419   /// Start a new scope for an inlined function.
420   void EmitInlineFunctionStart(CGBuilderTy &Builder, GlobalDecl GD);
421   /// End an inlined function scope.
422   void EmitInlineFunctionEnd(CGBuilderTy &Builder);
423 
424   /// Emit debug info for a function declaration.
425   /// \p Fn is set only when a declaration for a debug call site gets created.
426   void EmitFunctionDecl(GlobalDecl GD, SourceLocation Loc,
427                         QualType FnType, llvm::Function *Fn = nullptr);
428 
429   /// Emit debug info for an extern function being called.
430   /// This is needed for call site debug info.
431   void EmitFuncDeclForCallSite(llvm::CallBase *CallOrInvoke,
432                                QualType CalleeType,
433                                const FunctionDecl *CalleeDecl);
434 
435   /// Constructs the debug code for exiting a function.
436   void EmitFunctionEnd(CGBuilderTy &Builder, llvm::Function *Fn);
437 
438   /// Emit metadata to indicate the beginning of a new lexical block
439   /// and push the block onto the stack.
440   void EmitLexicalBlockStart(CGBuilderTy &Builder, SourceLocation Loc);
441 
442   /// Emit metadata to indicate the end of a new lexical block and pop
443   /// the current block.
444   void EmitLexicalBlockEnd(CGBuilderTy &Builder, SourceLocation Loc);
445 
446   /// Emit call to \c llvm.dbg.declare for an automatic variable
447   /// declaration.
448   /// Returns a pointer to the DILocalVariable associated with the
449   /// llvm.dbg.declare, or nullptr otherwise.
450   llvm::DILocalVariable *
451   EmitDeclareOfAutoVariable(const VarDecl *Decl, llvm::Value *AI,
452                             CGBuilderTy &Builder,
453                             const bool UsePointerValue = false);
454 
455   /// Emit call to \c llvm.dbg.label for an label.
456   void EmitLabel(const LabelDecl *D, CGBuilderTy &Builder);
457 
458   /// Emit call to \c llvm.dbg.declare for an imported variable
459   /// declaration in a block.
460   void EmitDeclareOfBlockDeclRefVariable(
461       const VarDecl *variable, llvm::Value *storage, CGBuilderTy &Builder,
462       const CGBlockInfo &blockInfo, llvm::Instruction *InsertPoint = nullptr);
463 
464   /// Emit call to \c llvm.dbg.declare for an argument variable
465   /// declaration.
466   void EmitDeclareOfArgVariable(const VarDecl *Decl, llvm::Value *AI,
467                                 unsigned ArgNo, CGBuilderTy &Builder);
468 
469   /// Emit call to \c llvm.dbg.declare for the block-literal argument
470   /// to a block invocation function.
471   void EmitDeclareOfBlockLiteralArgVariable(const CGBlockInfo &block,
472                                             StringRef Name, unsigned ArgNo,
473                                             llvm::AllocaInst *LocalAddr,
474                                             CGBuilderTy &Builder);
475 
476   /// Emit information about a global variable.
477   void EmitGlobalVariable(llvm::GlobalVariable *GV, const VarDecl *Decl);
478 
479   /// Emit a constant global variable's debug info.
480   void EmitGlobalVariable(const ValueDecl *VD, const APValue &Init);
481 
482   /// Emit information about an external variable.
483   void EmitExternalVariable(llvm::GlobalVariable *GV, const VarDecl *Decl);
484 
485   /// Emit C++ using directive.
486   void EmitUsingDirective(const UsingDirectiveDecl &UD);
487 
488   /// Emit the type explicitly casted to.
489   void EmitExplicitCastType(QualType Ty);
490 
491   /// Emit the type even if it might not be used.
492   void EmitAndRetainType(QualType Ty);
493 
494   /// Emit C++ using declaration.
495   void EmitUsingDecl(const UsingDecl &UD);
496 
497   /// Emit an @import declaration.
498   void EmitImportDecl(const ImportDecl &ID);
499 
500   /// Emit C++ namespace alias.
501   llvm::DIImportedEntity *EmitNamespaceAlias(const NamespaceAliasDecl &NA);
502 
503   /// Emit record type's standalone debug info.
504   llvm::DIType *getOrCreateRecordType(QualType Ty, SourceLocation L);
505 
506   /// Emit an Objective-C interface type standalone debug info.
507   llvm::DIType *getOrCreateInterfaceType(QualType Ty, SourceLocation Loc);
508 
509   /// Emit standalone debug info for a type.
510   llvm::DIType *getOrCreateStandaloneType(QualType Ty, SourceLocation Loc);
511 
512   /// Add heapallocsite metadata for MSAllocator calls.
513   void addHeapAllocSiteMetadata(llvm::CallBase *CallSite, QualType AllocatedTy,
514                                 SourceLocation Loc);
515 
516   void completeType(const EnumDecl *ED);
517   void completeType(const RecordDecl *RD);
518   void completeRequiredType(const RecordDecl *RD);
519   void completeClassData(const RecordDecl *RD);
520   void completeClass(const RecordDecl *RD);
521 
522   void completeTemplateDefinition(const ClassTemplateSpecializationDecl &SD);
523   void completeUnusedClass(const CXXRecordDecl &D);
524 
525   /// Create debug info for a macro defined by a #define directive or a macro
526   /// undefined by a #undef directive.
527   llvm::DIMacro *CreateMacro(llvm::DIMacroFile *Parent, unsigned MType,
528                              SourceLocation LineLoc, StringRef Name,
529                              StringRef Value);
530 
531   /// Create debug info for a file referenced by an #include directive.
532   llvm::DIMacroFile *CreateTempMacroFile(llvm::DIMacroFile *Parent,
533                                          SourceLocation LineLoc,
534                                          SourceLocation FileLoc);
535 
536 private:
537   /// Emit call to llvm.dbg.declare for a variable declaration.
538   /// Returns a pointer to the DILocalVariable associated with the
539   /// llvm.dbg.declare, or nullptr otherwise.
540   llvm::DILocalVariable *EmitDeclare(const VarDecl *decl, llvm::Value *AI,
541                                      llvm::Optional<unsigned> ArgNo,
542                                      CGBuilderTy &Builder,
543                                      const bool UsePointerValue = false);
544 
545   struct BlockByRefType {
546     /// The wrapper struct used inside the __block_literal struct.
547     llvm::DIType *BlockByRefWrapper;
548     /// The type as it appears in the source code.
549     llvm::DIType *WrappedType;
550   };
551 
552   /// Build up structure info for the byref.  See \a BuildByRefType.
553   BlockByRefType EmitTypeForVarWithBlocksAttr(const VarDecl *VD,
554                                               uint64_t *OffSet);
555 
556   /// Get context info for the DeclContext of \p Decl.
557   llvm::DIScope *getDeclContextDescriptor(const Decl *D);
558   /// Get context info for a given DeclContext \p Decl.
559   llvm::DIScope *getContextDescriptor(const Decl *Context,
560                                       llvm::DIScope *Default);
561 
562   llvm::DIScope *getCurrentContextDescriptor(const Decl *Decl);
563 
564   /// Create a forward decl for a RecordType in a given context.
565   llvm::DICompositeType *getOrCreateRecordFwdDecl(const RecordType *,
566                                                   llvm::DIScope *);
567 
568   /// Return current directory name.
569   StringRef getCurrentDirname();
570 
571   /// Create new compile unit.
572   void CreateCompileUnit();
573 
574   /// Compute the file checksum debug info for input file ID.
575   Optional<llvm::DIFile::ChecksumKind>
576   computeChecksum(FileID FID, SmallString<32> &Checksum) const;
577 
578   /// Get the source of the given file ID.
579   Optional<StringRef> getSource(const SourceManager &SM, FileID FID);
580 
581   /// Convenience function to get the file debug info descriptor for the input
582   /// location.
583   llvm::DIFile *getOrCreateFile(SourceLocation Loc);
584 
585   /// Create a file debug info descriptor for a source file.
586   llvm::DIFile *
587   createFile(StringRef FileName,
588              Optional<llvm::DIFile::ChecksumInfo<StringRef>> CSInfo,
589              Optional<StringRef> Source);
590 
591   /// Get the type from the cache or create a new type if necessary.
592   llvm::DIType *getOrCreateType(QualType Ty, llvm::DIFile *Fg);
593 
594   /// Get a reference to a clang module.  If \p CreateSkeletonCU is true,
595   /// this also creates a split dwarf skeleton compile unit.
596   llvm::DIModule *getOrCreateModuleRef(ASTSourceDescriptor Mod,
597                                        bool CreateSkeletonCU);
598 
599   /// DebugTypeExtRefs: If \p D originated in a clang module, return it.
600   llvm::DIModule *getParentModuleOrNull(const Decl *D);
601 
602   /// Get the type from the cache or create a new partial type if
603   /// necessary.
604   llvm::DICompositeType *getOrCreateLimitedType(const RecordType *Ty);
605 
606   /// Create type metadata for a source language type.
607   llvm::DIType *CreateTypeNode(QualType Ty, llvm::DIFile *Fg);
608 
609   /// Create new member and increase Offset by FType's size.
610   llvm::DIType *CreateMemberType(llvm::DIFile *Unit, QualType FType,
611                                  StringRef Name, uint64_t *Offset);
612 
613   /// Retrieve the DIDescriptor, if any, for the canonical form of this
614   /// declaration.
615   llvm::DINode *getDeclarationOrDefinition(const Decl *D);
616 
617   /// \return debug info descriptor to describe method
618   /// declaration for the given method definition.
619   llvm::DISubprogram *getFunctionDeclaration(const Decl *D);
620 
621   /// \return          debug info descriptor to the describe method declaration
622   ///                  for the given method definition.
623   /// \param FnType    For Objective-C methods, their type.
624   /// \param LineNo    The declaration's line number.
625   /// \param Flags     The DIFlags for the method declaration.
626   /// \param SPFlags   The subprogram-spcific flags for the method declaration.
627   llvm::DISubprogram *
628   getObjCMethodDeclaration(const Decl *D, llvm::DISubroutineType *FnType,
629                            unsigned LineNo, llvm::DINode::DIFlags Flags,
630                            llvm::DISubprogram::DISPFlags SPFlags);
631 
632   /// \return debug info descriptor to describe in-class static data
633   /// member declaration for the given out-of-class definition.  If D
634   /// is an out-of-class definition of a static data member of a
635   /// class, find its corresponding in-class declaration.
636   llvm::DIDerivedType *
637   getOrCreateStaticDataMemberDeclarationOrNull(const VarDecl *D);
638 
639   /// Helper that either creates a forward declaration or a stub.
640   llvm::DISubprogram *getFunctionFwdDeclOrStub(GlobalDecl GD, bool Stub);
641 
642   /// Create a subprogram describing the forward declaration
643   /// represented in the given FunctionDecl wrapped in a GlobalDecl.
644   llvm::DISubprogram *getFunctionForwardDeclaration(GlobalDecl GD);
645 
646   /// Create a DISubprogram describing the function
647   /// represented in the given FunctionDecl wrapped in a GlobalDecl.
648   llvm::DISubprogram *getFunctionStub(GlobalDecl GD);
649 
650   /// Create a global variable describing the forward declaration
651   /// represented in the given VarDecl.
652   llvm::DIGlobalVariable *
653   getGlobalVariableForwardDeclaration(const VarDecl *VD);
654 
655   /// Return a global variable that represents one of the collection of global
656   /// variables created for an anonmyous union.
657   ///
658   /// Recursively collect all of the member fields of a global
659   /// anonymous decl and create static variables for them. The first
660   /// time this is called it needs to be on a union and then from
661   /// there we can have additional unnamed fields.
662   llvm::DIGlobalVariableExpression *
663   CollectAnonRecordDecls(const RecordDecl *RD, llvm::DIFile *Unit,
664                          unsigned LineNo, StringRef LinkageName,
665                          llvm::GlobalVariable *Var, llvm::DIScope *DContext);
666 
667 
668   /// Return flags which enable debug info emission for call sites, provided
669   /// that it is supported and enabled.
670   llvm::DINode::DIFlags getCallSiteRelatedAttrs() const;
671 
672   /// Get the printing policy for producing names for debug info.
673   PrintingPolicy getPrintingPolicy() const;
674 
675   /// Get function name for the given FunctionDecl. If the name is
676   /// constructed on demand (e.g., C++ destructor) then the name is
677   /// stored on the side.
678   StringRef getFunctionName(const FunctionDecl *FD);
679 
680   /// Returns the unmangled name of an Objective-C method.
681   /// This is the display name for the debugging info.
682   StringRef getObjCMethodName(const ObjCMethodDecl *FD);
683 
684   /// Return selector name. This is used for debugging
685   /// info.
686   StringRef getSelectorName(Selector S);
687 
688   /// Get class name including template argument list.
689   StringRef getClassName(const RecordDecl *RD);
690 
691   /// Get the vtable name for the given class.
692   StringRef getVTableName(const CXXRecordDecl *Decl);
693 
694   /// Get the name to use in the debug info for a dynamic initializer or atexit
695   /// stub function.
696   StringRef getDynamicInitializerName(const VarDecl *VD,
697                                       DynamicInitKind StubKind,
698                                       llvm::Function *InitFn);
699 
700   /// Get line number for the location. If location is invalid
701   /// then use current location.
702   unsigned getLineNumber(SourceLocation Loc);
703 
704   /// Get column number for the location. If location is
705   /// invalid then use current location.
706   /// \param Force  Assume DebugColumnInfo option is true.
707   unsigned getColumnNumber(SourceLocation Loc, bool Force = false);
708 
709   /// Collect various properties of a FunctionDecl.
710   /// \param GD  A GlobalDecl whose getDecl() must return a FunctionDecl.
711   void collectFunctionDeclProps(GlobalDecl GD, llvm::DIFile *Unit,
712                                 StringRef &Name, StringRef &LinkageName,
713                                 llvm::DIScope *&FDContext,
714                                 llvm::DINodeArray &TParamsArray,
715                                 llvm::DINode::DIFlags &Flags);
716 
717   /// Collect various properties of a VarDecl.
718   void collectVarDeclProps(const VarDecl *VD, llvm::DIFile *&Unit,
719                            unsigned &LineNo, QualType &T, StringRef &Name,
720                            StringRef &LinkageName,
721                            llvm::MDTuple *&TemplateParameters,
722                            llvm::DIScope *&VDContext);
723 
724   /// Allocate a copy of \p A using the DebugInfoNames allocator
725   /// and return a reference to it. If multiple arguments are given the strings
726   /// are concatenated.
727   StringRef internString(StringRef A, StringRef B = StringRef()) {
728     char *Data = DebugInfoNames.Allocate<char>(A.size() + B.size());
729     if (!A.empty())
730       std::memcpy(Data, A.data(), A.size());
731     if (!B.empty())
732       std::memcpy(Data + A.size(), B.data(), B.size());
733     return StringRef(Data, A.size() + B.size());
734   }
735 };
736 
737 /// A scoped helper to set the current debug location to the specified
738 /// location or preferred location of the specified Expr.
739 class ApplyDebugLocation {
740 private:
741   void init(SourceLocation TemporaryLocation, bool DefaultToEmpty = false);
742   ApplyDebugLocation(CodeGenFunction &CGF, bool DefaultToEmpty,
743                      SourceLocation TemporaryLocation);
744 
745   llvm::DebugLoc OriginalLocation;
746   CodeGenFunction *CGF;
747 
748 public:
749   /// Set the location to the (valid) TemporaryLocation.
750   ApplyDebugLocation(CodeGenFunction &CGF, SourceLocation TemporaryLocation);
751   ApplyDebugLocation(CodeGenFunction &CGF, const Expr *E);
752   ApplyDebugLocation(CodeGenFunction &CGF, llvm::DebugLoc Loc);
753   ApplyDebugLocation(ApplyDebugLocation &&Other) : CGF(Other.CGF) {
754     Other.CGF = nullptr;
755   }
756   ApplyDebugLocation &operator=(ApplyDebugLocation &&) = default;
757 
758   ~ApplyDebugLocation();
759 
760   /// Apply TemporaryLocation if it is valid. Otherwise switch
761   /// to an artificial debug location that has a valid scope, but no
762   /// line information.
763   ///
764   /// Artificial locations are useful when emitting compiler-generated
765   /// helper functions that have no source location associated with
766   /// them. The DWARF specification allows the compiler to use the
767   /// special line number 0 to indicate code that can not be
768   /// attributed to any source location. Note that passing an empty
769   /// SourceLocation to CGDebugInfo::setLocation() will result in the
770   /// last valid location being reused.
771   static ApplyDebugLocation CreateArtificial(CodeGenFunction &CGF) {
772     return ApplyDebugLocation(CGF, false, SourceLocation());
773   }
774   /// Apply TemporaryLocation if it is valid. Otherwise switch
775   /// to an artificial debug location that has a valid scope, but no
776   /// line information.
777   static ApplyDebugLocation
778   CreateDefaultArtificial(CodeGenFunction &CGF,
779                           SourceLocation TemporaryLocation) {
780     return ApplyDebugLocation(CGF, false, TemporaryLocation);
781   }
782 
783   /// Set the IRBuilder to not attach debug locations.  Note that
784   /// passing an empty SourceLocation to \a CGDebugInfo::setLocation()
785   /// will result in the last valid location being reused.  Note that
786   /// all instructions that do not have a location at the beginning of
787   /// a function are counted towards to function prologue.
788   static ApplyDebugLocation CreateEmpty(CodeGenFunction &CGF) {
789     return ApplyDebugLocation(CGF, true, SourceLocation());
790   }
791 };
792 
793 /// A scoped helper to set the current debug location to an inlined location.
794 class ApplyInlineDebugLocation {
795   SourceLocation SavedLocation;
796   CodeGenFunction *CGF;
797 
798 public:
799   /// Set up the CodeGenFunction's DebugInfo to produce inline locations for the
800   /// function \p InlinedFn. The current debug location becomes the inlined call
801   /// site of the inlined function.
802   ApplyInlineDebugLocation(CodeGenFunction &CGF, GlobalDecl InlinedFn);
803   /// Restore everything back to the original state.
804   ~ApplyInlineDebugLocation();
805 };
806 
807 } // namespace CodeGen
808 } // namespace clang
809 
810 #endif // LLVM_CLANG_LIB_CODEGEN_CGDEBUGINFO_H
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