1 //===--- CGDebugInfo.h - DebugInfo for LLVM CodeGen -------------*- C++ -*-===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This is the source-level debug info generator for llvm translation.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_CLANG_LIB_CODEGEN_CGDEBUGINFO_H
15 #define LLVM_CLANG_LIB_CODEGEN_CGDEBUGINFO_H
16 
17 #include "CGBuilder.h"
18 #include "clang/AST/Expr.h"
19 #include "clang/AST/Type.h"
20 #include "clang/Basic/SourceLocation.h"
21 #include "clang/Frontend/CodeGenOptions.h"
22 #include "llvm/ADT/DenseMap.h"
23 #include "llvm/IR/DIBuilder.h"
24 #include "llvm/IR/DebugInfo.h"
25 #include "llvm/IR/ValueHandle.h"
26 #include "llvm/Support/Allocator.h"
27 
28 namespace llvm {
29 class MDNode;
30 }
31 
32 namespace clang {
33 class CXXMethodDecl;
34 class VarDecl;
35 class ObjCInterfaceDecl;
36 class ObjCIvarDecl;
37 class ClassTemplateSpecializationDecl;
38 class GlobalDecl;
39 class UsingDecl;
40 
41 namespace CodeGen {
42 class CodeGenModule;
43 class CodeGenFunction;
44 class CGBlockInfo;
45 
46 /// This class gathers all debug information during compilation and is
47 /// responsible for emitting to llvm globals or pass directly to the
48 /// backend.
49 class CGDebugInfo {
50   friend class ApplyDebugLocation;
51   friend class SaveAndRestoreLocation;
52   CodeGenModule &CGM;
53   const CodeGenOptions::DebugInfoKind DebugKind;
54   llvm::DIBuilder DBuilder;
55   llvm::DICompileUnit *TheCU = nullptr;
56   SourceLocation CurLoc;
57   llvm::DIType *VTablePtrType = nullptr;
58   llvm::DIType *ClassTy = nullptr;
59   llvm::DICompositeType *ObjTy = nullptr;
60   llvm::DIType *SelTy = nullptr;
61   llvm::DIType *OCLImage1dDITy = nullptr;
62   llvm::DIType *OCLImage1dArrayDITy = nullptr;
63   llvm::DIType *OCLImage1dBufferDITy = nullptr;
64   llvm::DIType *OCLImage2dDITy = nullptr;
65   llvm::DIType *OCLImage2dArrayDITy = nullptr;
66   llvm::DIType *OCLImage3dDITy = nullptr;
67   llvm::DIType *OCLEventDITy = nullptr;
68 
69   /// Cache of previously constructed Types.
70   llvm::DenseMap<const void *, llvm::TrackingMDRef> TypeCache;
71 
72   struct ObjCInterfaceCacheEntry {
73     const ObjCInterfaceType *Type;
74     llvm::DIType *Decl;
75     llvm::DIFile *Unit;
76     ObjCInterfaceCacheEntry(const ObjCInterfaceType *Type, llvm::DIType *Decl,
77                             llvm::DIFile *Unit)
78         : Type(Type), Decl(Decl), Unit(Unit) {}
79   };
80 
81   /// Cache of previously constructed interfaces which may change.
82   llvm::SmallVector<ObjCInterfaceCacheEntry, 32> ObjCInterfaceCache;
83 
84   /// Cache of references to AST files such as PCHs or modules.
85   llvm::DenseMap<uint64_t, llvm::DIModule *> ModuleRefCache;
86 
87   /// List of interfaces we want to keep even if orphaned.
88   std::vector<void *> RetainedTypes;
89 
90   /// Cache of forward declared types to RAUW at the end of
91   /// compilation.
92   std::vector<std::pair<const TagType *, llvm::TrackingMDRef>> ReplaceMap;
93 
94   /// Cache of replaceable forward declarartions (functions and
95   /// variables) to RAUW at the end of compilation.
96   std::vector<std::pair<const DeclaratorDecl *, llvm::TrackingMDRef>>
97       FwdDeclReplaceMap;
98 
99   /// Keep track of our current nested lexical block.
100   std::vector<llvm::TypedTrackingMDRef<llvm::DIScope>> LexicalBlockStack;
101   llvm::DenseMap<const Decl *, llvm::TrackingMDRef> RegionMap;
102   /// Keep track of LexicalBlockStack counter at the beginning of a
103   /// function. This is used to pop unbalanced regions at the end of a
104   /// function.
105   std::vector<unsigned> FnBeginRegionCount;
106 
107   /// This is a storage for names that are constructed on demand. For
108   /// example, C++ destructors, C++ operators etc..
109   llvm::BumpPtrAllocator DebugInfoNames;
110   StringRef CWDName;
111 
112   llvm::DenseMap<const char *, llvm::TrackingMDRef> DIFileCache;
113   llvm::DenseMap<const FunctionDecl *, llvm::TrackingMDRef> SPCache;
114   /// Cache declarations relevant to DW_TAG_imported_declarations (C++
115   /// using declarations) that aren't covered by other more specific caches.
116   llvm::DenseMap<const Decl *, llvm::TrackingMDRef> DeclCache;
117   llvm::DenseMap<const NamespaceDecl *, llvm::TrackingMDRef> NameSpaceCache;
118   llvm::DenseMap<const NamespaceAliasDecl *, llvm::TrackingMDRef>
119       NamespaceAliasCache;
120   llvm::DenseMap<const Decl *, llvm::TypedTrackingMDRef<llvm::DIDerivedType>>
121       StaticDataMemberCache;
122 
123   /// Helper functions for getOrCreateType.
124   /// @{
125   /// Currently the checksum of an interface includes the number of
126   /// ivars and property accessors.
127   unsigned Checksum(const ObjCInterfaceDecl *InterfaceDecl);
128   llvm::DIType *CreateType(const BuiltinType *Ty);
129   llvm::DIType *CreateType(const ComplexType *Ty);
130   llvm::DIType *CreateQualifiedType(QualType Ty, llvm::DIFile *Fg);
131   llvm::DIType *CreateType(const TypedefType *Ty, llvm::DIFile *Fg);
132   llvm::DIType *CreateType(const TemplateSpecializationType *Ty,
133                            llvm::DIFile *Fg);
134   llvm::DIType *CreateType(const ObjCObjectPointerType *Ty, llvm::DIFile *F);
135   llvm::DIType *CreateType(const PointerType *Ty, llvm::DIFile *F);
136   llvm::DIType *CreateType(const BlockPointerType *Ty, llvm::DIFile *F);
137   llvm::DIType *CreateType(const FunctionType *Ty, llvm::DIFile *F);
138   /// Get structure or union type.
139   llvm::DIType *CreateType(const RecordType *Tyg);
140   llvm::DIType *CreateTypeDefinition(const RecordType *Ty);
141   llvm::DICompositeType *CreateLimitedType(const RecordType *Ty);
142   void CollectContainingType(const CXXRecordDecl *RD,
143                              llvm::DICompositeType *CT);
144   /// Get Objective-C interface type.
145   llvm::DIType *CreateType(const ObjCInterfaceType *Ty, llvm::DIFile *F);
146   llvm::DIType *CreateTypeDefinition(const ObjCInterfaceType *Ty,
147                                      llvm::DIFile *F);
148   /// Get Objective-C object type.
149   llvm::DIType *CreateType(const ObjCObjectType *Ty, llvm::DIFile *F);
150   llvm::DIType *CreateType(const VectorType *Ty, llvm::DIFile *F);
151   llvm::DIType *CreateType(const ArrayType *Ty, llvm::DIFile *F);
152   llvm::DIType *CreateType(const LValueReferenceType *Ty, llvm::DIFile *F);
153   llvm::DIType *CreateType(const RValueReferenceType *Ty, llvm::DIFile *Unit);
154   llvm::DIType *CreateType(const MemberPointerType *Ty, llvm::DIFile *F);
155   llvm::DIType *CreateType(const AtomicType *Ty, llvm::DIFile *F);
156   /// Get enumeration type.
157   llvm::DIType *CreateEnumType(const EnumType *Ty);
158   llvm::DIType *CreateTypeDefinition(const EnumType *Ty);
159   /// Look up the completed type for a self pointer in the TypeCache and
160   /// create a copy of it with the ObjectPointer and Artificial flags
161   /// set. If the type is not cached, a new one is created. This should
162   /// never happen though, since creating a type for the implicit self
163   /// argument implies that we already parsed the interface definition
164   /// and the ivar declarations in the implementation.
165   llvm::DIType *CreateSelfType(const QualType &QualTy, llvm::DIType *Ty);
166   /// @}
167 
168   /// Get the type from the cache or return null type if it doesn't
169   /// exist.
170   llvm::DIType *getTypeOrNull(const QualType);
171   /// Return the debug type for a C++ method.
172   /// \arg CXXMethodDecl is of FunctionType. This function type is
173   /// not updated to include implicit \c this pointer. Use this routine
174   /// to get a method type which includes \c this pointer.
175   llvm::DISubroutineType *getOrCreateMethodType(const CXXMethodDecl *Method,
176                                                 llvm::DIFile *F);
177   llvm::DISubroutineType *
178   getOrCreateInstanceMethodType(QualType ThisPtr, const FunctionProtoType *Func,
179                                 llvm::DIFile *Unit);
180   llvm::DISubroutineType *
181   getOrCreateFunctionType(const Decl *D, QualType FnType, llvm::DIFile *F);
182   /// \return debug info descriptor for vtable.
183   llvm::DIType *getOrCreateVTablePtrType(llvm::DIFile *F);
184   /// \return namespace descriptor for the given namespace decl.
185   llvm::DINamespace *getOrCreateNameSpace(const NamespaceDecl *N);
186   llvm::DIType *getOrCreateTypeDeclaration(QualType PointeeTy, llvm::DIFile *F);
187   llvm::DIType *CreatePointerLikeType(llvm::dwarf::Tag Tag, const Type *Ty,
188                                       QualType PointeeTy, llvm::DIFile *F);
189 
190   llvm::Value *getCachedInterfaceTypeOrNull(const QualType Ty);
191   llvm::DIType *getOrCreateStructPtrType(StringRef Name, llvm::DIType *&Cache);
192 
193   /// A helper function to create a subprogram for a single member
194   /// function GlobalDecl.
195   llvm::DISubprogram *CreateCXXMemberFunction(const CXXMethodDecl *Method,
196                                               llvm::DIFile *F,
197                                               llvm::DIType *RecordTy);
198 
199   /// A helper function to collect debug info for C++ member
200   /// functions. This is used while creating debug info entry for a
201   /// Record.
202   void CollectCXXMemberFunctions(const CXXRecordDecl *Decl, llvm::DIFile *F,
203                                  SmallVectorImpl<llvm::Metadata *> &E,
204                                  llvm::DIType *T);
205 
206   /// A helper function to collect debug info for C++ base
207   /// classes. This is used while creating debug info entry for a
208   /// Record.
209   void CollectCXXBases(const CXXRecordDecl *Decl, llvm::DIFile *F,
210                        SmallVectorImpl<llvm::Metadata *> &EltTys,
211                        llvm::DIType *RecordTy);
212 
213   /// A helper function to collect template parameters.
214   llvm::DINodeArray CollectTemplateParams(const TemplateParameterList *TPList,
215                                           ArrayRef<TemplateArgument> TAList,
216                                           llvm::DIFile *Unit);
217   /// A helper function to collect debug info for function template
218   /// parameters.
219   llvm::DINodeArray CollectFunctionTemplateParams(const FunctionDecl *FD,
220                                                   llvm::DIFile *Unit);
221 
222   /// A helper function to collect debug info for template
223   /// parameters.
224   llvm::DINodeArray
225   CollectCXXTemplateParams(const ClassTemplateSpecializationDecl *TS,
226                            llvm::DIFile *F);
227 
228   llvm::DIType *createFieldType(StringRef name, QualType type,
229                                 uint64_t sizeInBitsOverride, SourceLocation loc,
230                                 AccessSpecifier AS, uint64_t offsetInBits,
231                                 llvm::DIFile *tunit, llvm::DIScope *scope,
232                                 const RecordDecl *RD = nullptr);
233 
234   /// Helpers for collecting fields of a record.
235   /// @{
236   void CollectRecordLambdaFields(const CXXRecordDecl *CXXDecl,
237                                  SmallVectorImpl<llvm::Metadata *> &E,
238                                  llvm::DIType *RecordTy);
239   llvm::DIDerivedType *CreateRecordStaticField(const VarDecl *Var,
240                                                llvm::DIType *RecordTy,
241                                                const RecordDecl *RD);
242   void CollectRecordNormalField(const FieldDecl *Field, uint64_t OffsetInBits,
243                                 llvm::DIFile *F,
244                                 SmallVectorImpl<llvm::Metadata *> &E,
245                                 llvm::DIType *RecordTy, const RecordDecl *RD);
246   void CollectRecordFields(const RecordDecl *Decl, llvm::DIFile *F,
247                            SmallVectorImpl<llvm::Metadata *> &E,
248                            llvm::DICompositeType *RecordTy);
249 
250   /// If the C++ class has vtable info then insert appropriate debug
251   /// info entry in EltTys vector.
252   void CollectVTableInfo(const CXXRecordDecl *Decl, llvm::DIFile *F,
253                          SmallVectorImpl<llvm::Metadata *> &EltTys);
254   /// @}
255 
256   /// Create a new lexical block node and push it on the stack.
257   void CreateLexicalBlock(SourceLocation Loc);
258 
259 public:
260   CGDebugInfo(CodeGenModule &CGM);
261   ~CGDebugInfo();
262 
263   void finalize();
264 
265   /// Update the current source location. If \arg loc is invalid it is
266   /// ignored.
267   void setLocation(SourceLocation Loc);
268 
269   /// Emit metadata to indicate a change in line/column information in
270   /// the source file. If the location is invalid, the previous
271   /// location will be reused.
272   void EmitLocation(CGBuilderTy &Builder, SourceLocation Loc);
273 
274   /// Emit a call to llvm.dbg.function.start to indicate
275   /// start of a new function.
276   /// \param Loc       The location of the function header.
277   /// \param ScopeLoc  The location of the function body.
278   void EmitFunctionStart(GlobalDecl GD, SourceLocation Loc,
279                          SourceLocation ScopeLoc, QualType FnType,
280                          llvm::Function *Fn, CGBuilderTy &Builder);
281 
282   /// Constructs the debug code for exiting a function.
283   void EmitFunctionEnd(CGBuilderTy &Builder);
284 
285   /// Emit metadata to indicate the beginning of a new lexical block
286   /// and push the block onto the stack.
287   void EmitLexicalBlockStart(CGBuilderTy &Builder, SourceLocation Loc);
288 
289   /// Emit metadata to indicate the end of a new lexical block and pop
290   /// the current block.
291   void EmitLexicalBlockEnd(CGBuilderTy &Builder, SourceLocation Loc);
292 
293   /// Emit call to \c llvm.dbg.declare for an automatic variable
294   /// declaration.
295   void EmitDeclareOfAutoVariable(const VarDecl *Decl, llvm::Value *AI,
296                                  CGBuilderTy &Builder);
297 
298   /// Emit call to \c llvm.dbg.declare for an imported variable
299   /// declaration in a block.
300   void EmitDeclareOfBlockDeclRefVariable(const VarDecl *variable,
301                                          llvm::Value *storage,
302                                          CGBuilderTy &Builder,
303                                          const CGBlockInfo &blockInfo,
304                                          llvm::Instruction *InsertPoint = 0);
305 
306   /// Emit call to \c llvm.dbg.declare for an argument variable
307   /// declaration.
308   void EmitDeclareOfArgVariable(const VarDecl *Decl, llvm::Value *AI,
309                                 unsigned ArgNo, CGBuilderTy &Builder);
310 
311   /// Emit call to \c llvm.dbg.declare for the block-literal argument
312   /// to a block invocation function.
313   void EmitDeclareOfBlockLiteralArgVariable(const CGBlockInfo &block,
314                                             llvm::Value *Arg, unsigned ArgNo,
315                                             llvm::Value *LocalAddr,
316                                             CGBuilderTy &Builder);
317 
318   /// Emit information about a global variable.
319   void EmitGlobalVariable(llvm::GlobalVariable *GV, const VarDecl *Decl);
320 
321   /// Emit global variable's debug info.
322   void EmitGlobalVariable(const ValueDecl *VD, llvm::Constant *Init);
323 
324   /// Emit C++ using directive.
325   void EmitUsingDirective(const UsingDirectiveDecl &UD);
326 
327   /// Emit the type explicitly casted to.
328   void EmitExplicitCastType(QualType Ty);
329 
330   /// Emit C++ using declaration.
331   void EmitUsingDecl(const UsingDecl &UD);
332 
333   /// Emit an @import declaration.
334   void EmitImportDecl(const ImportDecl &ID);
335 
336   /// Emit C++ namespace alias.
337   llvm::DIImportedEntity *EmitNamespaceAlias(const NamespaceAliasDecl &NA);
338 
339   /// Emit record type's standalone debug info.
340   llvm::DIType *getOrCreateRecordType(QualType Ty, SourceLocation L);
341 
342   /// Emit an Objective-C interface type standalone debug info.
343   llvm::DIType *getOrCreateInterfaceType(QualType Ty, SourceLocation Loc);
344 
345   void completeType(const EnumDecl *ED);
346   void completeType(const RecordDecl *RD);
347   void completeRequiredType(const RecordDecl *RD);
348   void completeClassData(const RecordDecl *RD);
349 
350   void completeTemplateDefinition(const ClassTemplateSpecializationDecl &SD);
351 
352 private:
353   /// Emit call to llvm.dbg.declare for a variable declaration.
354   /// Tag accepts custom types DW_TAG_arg_variable and DW_TAG_auto_variable,
355   /// otherwise would be of type llvm::dwarf::Tag.
356   void EmitDeclare(const VarDecl *decl, llvm::dwarf::Tag Tag, llvm::Value *AI,
357                    unsigned ArgNo, CGBuilderTy &Builder);
358 
359   /// Build up structure info for the byref.  See \a BuildByRefType.
360   llvm::DIType *EmitTypeForVarWithBlocksAttr(const VarDecl *VD,
361                                              uint64_t *OffSet);
362 
363   /// Get context info for the decl.
364   llvm::DIScope *getContextDescriptor(const Decl *Decl);
365 
366   llvm::DIScope *getCurrentContextDescriptor(const Decl *Decl);
367 
368   /// Create a forward decl for a RecordType in a given context.
369   llvm::DICompositeType *getOrCreateRecordFwdDecl(const RecordType *,
370                                                   llvm::DIScope *);
371 
372   /// Return current directory name.
373   StringRef getCurrentDirname();
374 
375   /// Create new compile unit.
376   void CreateCompileUnit();
377 
378   /// Get the file debug info descriptor for the input location.
379   llvm::DIFile *getOrCreateFile(SourceLocation Loc);
380 
381   /// Get the file info for main compile unit.
382   llvm::DIFile *getOrCreateMainFile();
383 
384   /// Get the type from the cache or create a new type if necessary.
385   llvm::DIType *getOrCreateType(QualType Ty, llvm::DIFile *Fg);
386 
387   /// Get a reference to a clang module.
388   llvm::DIModule *
389   getOrCreateModuleRef(ExternalASTSource::ASTSourceDescriptor Mod);
390 
391   /// Get the type from the cache or create a new partial type if
392   /// necessary.
393   llvm::DICompositeType *getOrCreateLimitedType(const RecordType *Ty,
394                                                 llvm::DIFile *F);
395 
396   /// Create type metadata for a source language type.
397   llvm::DIType *CreateTypeNode(QualType Ty, llvm::DIFile *Fg);
398 
399   /// Return the underlying ObjCInterfaceDecl if \arg Ty is an
400   /// ObjCInterface or a pointer to one.
401   ObjCInterfaceDecl *getObjCInterfaceDecl(QualType Ty);
402 
403   /// Create new member and increase Offset by FType's size.
404   llvm::DIType *CreateMemberType(llvm::DIFile *Unit, QualType FType,
405                                  StringRef Name, uint64_t *Offset);
406 
407   /// Retrieve the DIDescriptor, if any, for the canonical form of this
408   /// declaration.
409   llvm::DINode *getDeclarationOrDefinition(const Decl *D);
410 
411   /// \return debug info descriptor to describe method
412   /// declaration for the given method definition.
413   llvm::DISubprogram *getFunctionDeclaration(const Decl *D);
414 
415   /// \return debug info descriptor to describe in-class static data
416   /// member declaration for the given out-of-class definition.  If D
417   /// is an out-of-class definition of a static data member of a
418   /// class, find its corresponding in-class declaration.
419   llvm::DIDerivedType *
420   getOrCreateStaticDataMemberDeclarationOrNull(const VarDecl *D);
421 
422   /// Create a subprogram describing the forward declaration
423   /// represented in the given FunctionDecl.
424   llvm::DISubprogram *getFunctionForwardDeclaration(const FunctionDecl *FD);
425 
426   /// Create a global variable describing the forward decalration
427   /// represented in the given VarDecl.
428   llvm::DIGlobalVariable *
429   getGlobalVariableForwardDeclaration(const VarDecl *VD);
430 
431   /// \brief Return a global variable that represents one of the
432   /// collection of global variables created for an anonmyous union.
433   ///
434   /// Recursively collect all of the member fields of a global
435   /// anonymous decl and create static variables for them. The first
436   /// time this is called it needs to be on a union and then from
437   /// there we can have additional unnamed fields.
438   llvm::DIGlobalVariable *
439   CollectAnonRecordDecls(const RecordDecl *RD, llvm::DIFile *Unit,
440                          unsigned LineNo, StringRef LinkageName,
441                          llvm::GlobalVariable *Var, llvm::DIScope *DContext);
442 
443   /// Get function name for the given FunctionDecl. If the name is
444   /// constructed on demand (e.g., C++ destructor) then the name is
445   /// stored on the side.
446   StringRef getFunctionName(const FunctionDecl *FD);
447 
448   /// Returns the unmangled name of an Objective-C method.
449   /// This is the display name for the debugging info.
450   StringRef getObjCMethodName(const ObjCMethodDecl *FD);
451 
452   /// Return selector name. This is used for debugging
453   /// info.
454   StringRef getSelectorName(Selector S);
455 
456   /// Get class name including template argument list.
457   StringRef getClassName(const RecordDecl *RD);
458 
459   /// Get the vtable name for the given class.
460   StringRef getVTableName(const CXXRecordDecl *Decl);
461 
462   /// Get line number for the location. If location is invalid
463   /// then use current location.
464   unsigned getLineNumber(SourceLocation Loc);
465 
466   /// Get column number for the location. If location is
467   /// invalid then use current location.
468   /// \param Force  Assume DebugColumnInfo option is true.
469   unsigned getColumnNumber(SourceLocation Loc, bool Force = false);
470 
471   /// Collect various properties of a FunctionDecl.
472   /// \param GD  A GlobalDecl whose getDecl() must return a FunctionDecl.
473   void collectFunctionDeclProps(GlobalDecl GD, llvm::DIFile *Unit,
474                                 StringRef &Name, StringRef &LinkageName,
475                                 llvm::DIScope *&FDContext,
476                                 llvm::DINodeArray &TParamsArray,
477                                 unsigned &Flags);
478 
479   /// Collect various properties of a VarDecl.
480   void collectVarDeclProps(const VarDecl *VD, llvm::DIFile *&Unit,
481                            unsigned &LineNo, QualType &T, StringRef &Name,
482                            StringRef &LinkageName, llvm::DIScope *&VDContext);
483 
484   /// Allocate a copy of \p A using the DebugInfoNames allocator
485   /// and return a reference to it. If multiple arguments are given the strings
486   /// are concatenated.
487   StringRef internString(StringRef A, StringRef B = StringRef()) {
488     char *Data = DebugInfoNames.Allocate<char>(A.size() + B.size());
489     std::memcpy(Data, A.data(), A.size());
490     std::memcpy(Data + A.size(), B.data(), B.size());
491     return StringRef(Data, A.size() + B.size());
492   }
493 };
494 
495 /// A scoped helper to set the current debug location to the specified
496 /// location or preferred location of the specified Expr.
497 class ApplyDebugLocation {
498 private:
499   void init(SourceLocation TemporaryLocation, bool DefaultToEmpty = false);
500   ApplyDebugLocation(CodeGenFunction &CGF, bool DefaultToEmpty,
501                      SourceLocation TemporaryLocation);
502 
503   llvm::DebugLoc OriginalLocation;
504   CodeGenFunction &CGF;
505 
506 public:
507   /// Set the location to the (valid) TemporaryLocation.
508   ApplyDebugLocation(CodeGenFunction &CGF, SourceLocation TemporaryLocation);
509   ApplyDebugLocation(CodeGenFunction &CGF, const Expr *E);
510   ApplyDebugLocation(CodeGenFunction &CGF, llvm::DebugLoc Loc);
511 
512   ~ApplyDebugLocation();
513 
514   /// \brief Apply TemporaryLocation if it is valid. Otherwise switch
515   /// to an artificial debug location that has a valid scope, but no
516   /// line information.
517   ///
518   /// Artificial locations are useful when emitting compiler-generated
519   /// helper functions that have no source location associated with
520   /// them. The DWARF specification allows the compiler to use the
521   /// special line number 0 to indicate code that can not be
522   /// attributed to any source location. Note that passing an empty
523   /// SourceLocation to CGDebugInfo::setLocation() will result in the
524   /// last valid location being reused.
525   static ApplyDebugLocation CreateArtificial(CodeGenFunction &CGF) {
526     return ApplyDebugLocation(CGF, false, SourceLocation());
527   }
528   /// \brief Apply TemporaryLocation if it is valid. Otherwise switch
529   /// to an artificial debug location that has a valid scope, but no
530   /// line information.
531   static ApplyDebugLocation
532   CreateDefaultArtificial(CodeGenFunction &CGF,
533                           SourceLocation TemporaryLocation) {
534     return ApplyDebugLocation(CGF, false, TemporaryLocation);
535   }
536 
537   /// Set the IRBuilder to not attach debug locations.  Note that
538   /// passing an empty SourceLocation to \a CGDebugInfo::setLocation()
539   /// will result in the last valid location being reused.  Note that
540   /// all instructions that do not have a location at the beginning of
541   /// a function are counted towards to funciton prologue.
542   static ApplyDebugLocation CreateEmpty(CodeGenFunction &CGF) {
543     return ApplyDebugLocation(CGF, true, SourceLocation());
544   }
545 
546   /// \brief Apply TemporaryLocation if it is valid. Otherwise set the IRBuilder
547   /// to not attach debug locations.
548   static ApplyDebugLocation
549   CreateDefaultEmpty(CodeGenFunction &CGF, SourceLocation TemporaryLocation) {
550     return ApplyDebugLocation(CGF, true, TemporaryLocation);
551   }
552 };
553 
554 } // namespace CodeGen
555 } // namespace clang
556 
557 #endif
558