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/ADT/Optional.h"
24 #include "llvm/IR/DIBuilder.h"
25 #include "llvm/IR/DebugInfo.h"
26 #include "llvm/IR/ValueHandle.h"
27 #include "llvm/Support/Allocator.h"
28 
29 namespace llvm {
30 class MDNode;
31 }
32 
33 namespace clang {
34 class CXXMethodDecl;
35 class ClassTemplateSpecializationDecl;
36 class GlobalDecl;
37 class ModuleMap;
38 class ObjCInterfaceDecl;
39 class ObjCIvarDecl;
40 class UsingDecl;
41 class VarDecl;
42 
43 namespace CodeGen {
44 class CodeGenModule;
45 class CodeGenFunction;
46 class CGBlockInfo;
47 
48 /// This class gathers all debug information during compilation and is
49 /// responsible for emitting to llvm globals or pass directly to the
50 /// backend.
51 class CGDebugInfo {
52   friend class ApplyDebugLocation;
53   friend class SaveAndRestoreLocation;
54   CodeGenModule &CGM;
55   const CodeGenOptions::DebugInfoKind DebugKind;
56   bool DebugTypeExtRefs;
57   llvm::DIBuilder DBuilder;
58   llvm::DICompileUnit *TheCU = nullptr;
59   ModuleMap *ClangModuleMap = nullptr;
60   SourceLocation CurLoc;
61   llvm::DIType *VTablePtrType = nullptr;
62   llvm::DIType *ClassTy = nullptr;
63   llvm::DICompositeType *ObjTy = nullptr;
64   llvm::DIType *SelTy = nullptr;
65   llvm::DIType *OCLImage1dDITy = nullptr;
66   llvm::DIType *OCLImage1dArrayDITy = nullptr;
67   llvm::DIType *OCLImage1dBufferDITy = nullptr;
68   llvm::DIType *OCLImage2dDITy = nullptr;
69   llvm::DIType *OCLImage2dArrayDITy = nullptr;
70   llvm::DIType *OCLImage2dDepthDITy = nullptr;
71   llvm::DIType *OCLImage2dArrayDepthDITy = nullptr;
72   llvm::DIType *OCLImage2dMSAADITy = nullptr;
73   llvm::DIType *OCLImage2dArrayMSAADITy = nullptr;
74   llvm::DIType *OCLImage2dMSAADepthDITy = nullptr;
75   llvm::DIType *OCLImage2dArrayMSAADepthDITy = nullptr;
76   llvm::DIType *OCLImage3dDITy = nullptr;
77   llvm::DIType *OCLEventDITy = nullptr;
78   llvm::DIType *OCLClkEventDITy = nullptr;
79   llvm::DIType *OCLQueueDITy = nullptr;
80   llvm::DIType *OCLNDRangeDITy = nullptr;
81   llvm::DIType *OCLReserveIDDITy = nullptr;
82 
83   /// Cache of previously constructed Types.
84   llvm::DenseMap<const void *, llvm::TrackingMDRef> TypeCache;
85 
86   struct ObjCInterfaceCacheEntry {
87     const ObjCInterfaceType *Type;
88     llvm::DIType *Decl;
89     llvm::DIFile *Unit;
90     ObjCInterfaceCacheEntry(const ObjCInterfaceType *Type, llvm::DIType *Decl,
91                             llvm::DIFile *Unit)
92         : Type(Type), Decl(Decl), Unit(Unit) {}
93   };
94 
95   /// Cache of previously constructed interfaces which may change.
96   llvm::SmallVector<ObjCInterfaceCacheEntry, 32> ObjCInterfaceCache;
97 
98   /// Cache of references to clang modules and precompiled headers.
99   llvm::DenseMap<const Module *, llvm::TrackingMDRef> ModuleCache;
100 
101   /// List of interfaces we want to keep even if orphaned.
102   std::vector<void *> RetainedTypes;
103 
104   /// Cache of forward declared types to RAUW at the end of
105   /// compilation.
106   std::vector<std::pair<const TagType *, llvm::TrackingMDRef>> ReplaceMap;
107 
108   /// Cache of replaceable forward declarartions (functions and
109   /// variables) to RAUW at the end of compilation.
110   std::vector<std::pair<const DeclaratorDecl *, llvm::TrackingMDRef>>
111       FwdDeclReplaceMap;
112 
113   /// Keep track of our current nested lexical block.
114   std::vector<llvm::TypedTrackingMDRef<llvm::DIScope>> LexicalBlockStack;
115   llvm::DenseMap<const Decl *, llvm::TrackingMDRef> RegionMap;
116   /// Keep track of LexicalBlockStack counter at the beginning of a
117   /// function. This is used to pop unbalanced regions at the end of a
118   /// function.
119   std::vector<unsigned> FnBeginRegionCount;
120 
121   /// This is a storage for names that are constructed on demand. For
122   /// example, C++ destructors, C++ operators etc..
123   llvm::BumpPtrAllocator DebugInfoNames;
124   StringRef CWDName;
125 
126   llvm::DenseMap<const char *, llvm::TrackingMDRef> DIFileCache;
127   llvm::DenseMap<const FunctionDecl *, llvm::TrackingMDRef> SPCache;
128   /// Cache declarations relevant to DW_TAG_imported_declarations (C++
129   /// using declarations) that aren't covered by other more specific caches.
130   llvm::DenseMap<const Decl *, llvm::TrackingMDRef> DeclCache;
131   llvm::DenseMap<const NamespaceDecl *, llvm::TrackingMDRef> NameSpaceCache;
132   llvm::DenseMap<const NamespaceAliasDecl *, llvm::TrackingMDRef>
133       NamespaceAliasCache;
134   llvm::DenseMap<const Decl *, llvm::TypedTrackingMDRef<llvm::DIDerivedType>>
135       StaticDataMemberCache;
136 
137   /// Helper functions for getOrCreateType.
138   /// @{
139   /// Currently the checksum of an interface includes the number of
140   /// ivars and property accessors.
141   unsigned Checksum(const ObjCInterfaceDecl *InterfaceDecl);
142   llvm::DIType *CreateType(const BuiltinType *Ty);
143   llvm::DIType *CreateType(const ComplexType *Ty);
144   llvm::DIType *CreateQualifiedType(QualType Ty, llvm::DIFile *Fg);
145   llvm::DIType *CreateType(const TypedefType *Ty, llvm::DIFile *Fg);
146   llvm::DIType *CreateType(const TemplateSpecializationType *Ty,
147                            llvm::DIFile *Fg);
148   llvm::DIType *CreateType(const ObjCObjectPointerType *Ty, llvm::DIFile *F);
149   llvm::DIType *CreateType(const PointerType *Ty, llvm::DIFile *F);
150   llvm::DIType *CreateType(const BlockPointerType *Ty, llvm::DIFile *F);
151   llvm::DIType *CreateType(const FunctionType *Ty, llvm::DIFile *F);
152   /// Get structure or union type.
153   llvm::DIType *CreateType(const RecordType *Tyg);
154   llvm::DIType *CreateTypeDefinition(const RecordType *Ty);
155   llvm::DICompositeType *CreateLimitedType(const RecordType *Ty);
156   void CollectContainingType(const CXXRecordDecl *RD,
157                              llvm::DICompositeType *CT);
158   /// Get Objective-C interface type.
159   llvm::DIType *CreateType(const ObjCInterfaceType *Ty, llvm::DIFile *F);
160   llvm::DIType *CreateTypeDefinition(const ObjCInterfaceType *Ty,
161                                      llvm::DIFile *F);
162   /// Get Objective-C object type.
163   llvm::DIType *CreateType(const ObjCObjectType *Ty, llvm::DIFile *F);
164   llvm::DIType *CreateType(const VectorType *Ty, llvm::DIFile *F);
165   llvm::DIType *CreateType(const ArrayType *Ty, llvm::DIFile *F);
166   llvm::DIType *CreateType(const LValueReferenceType *Ty, llvm::DIFile *F);
167   llvm::DIType *CreateType(const RValueReferenceType *Ty, llvm::DIFile *Unit);
168   llvm::DIType *CreateType(const MemberPointerType *Ty, llvm::DIFile *F);
169   llvm::DIType *CreateType(const AtomicType *Ty, llvm::DIFile *F);
170   /// Get enumeration type.
171   llvm::DIType *CreateEnumType(const EnumType *Ty);
172   llvm::DIType *CreateTypeDefinition(const EnumType *Ty);
173   /// Look up the completed type for a self pointer in the TypeCache and
174   /// create a copy of it with the ObjectPointer and Artificial flags
175   /// set. If the type is not cached, a new one is created. This should
176   /// never happen though, since creating a type for the implicit self
177   /// argument implies that we already parsed the interface definition
178   /// and the ivar declarations in the implementation.
179   llvm::DIType *CreateSelfType(const QualType &QualTy, llvm::DIType *Ty);
180   /// @}
181 
182   /// Get the type from the cache or return null type if it doesn't
183   /// exist.
184   llvm::DIType *getTypeOrNull(const QualType);
185   /// Return the debug type for a C++ method.
186   /// \arg CXXMethodDecl is of FunctionType. This function type is
187   /// not updated to include implicit \c this pointer. Use this routine
188   /// to get a method type which includes \c this pointer.
189   llvm::DISubroutineType *getOrCreateMethodType(const CXXMethodDecl *Method,
190                                                 llvm::DIFile *F);
191   llvm::DISubroutineType *
192   getOrCreateInstanceMethodType(QualType ThisPtr, const FunctionProtoType *Func,
193                                 llvm::DIFile *Unit);
194   llvm::DISubroutineType *
195   getOrCreateFunctionType(const Decl *D, QualType FnType, llvm::DIFile *F);
196   /// \return debug info descriptor for vtable.
197   llvm::DIType *getOrCreateVTablePtrType(llvm::DIFile *F);
198   /// \return namespace descriptor for the given namespace decl.
199   llvm::DINamespace *getOrCreateNameSpace(const NamespaceDecl *N);
200   llvm::DIType *getOrCreateTypeDeclaration(QualType PointeeTy, llvm::DIFile *F);
201   llvm::DIType *CreatePointerLikeType(llvm::dwarf::Tag Tag, const Type *Ty,
202                                       QualType PointeeTy, llvm::DIFile *F);
203 
204   llvm::Value *getCachedInterfaceTypeOrNull(const QualType Ty);
205   llvm::DIType *getOrCreateStructPtrType(StringRef Name, llvm::DIType *&Cache);
206 
207   /// A helper function to create a subprogram for a single member
208   /// function GlobalDecl.
209   llvm::DISubprogram *CreateCXXMemberFunction(const CXXMethodDecl *Method,
210                                               llvm::DIFile *F,
211                                               llvm::DIType *RecordTy);
212 
213   /// A helper function to collect debug info for C++ member
214   /// functions. This is used while creating debug info entry for a
215   /// Record.
216   void CollectCXXMemberFunctions(const CXXRecordDecl *Decl, llvm::DIFile *F,
217                                  SmallVectorImpl<llvm::Metadata *> &E,
218                                  llvm::DIType *T);
219 
220   /// A helper function to collect debug info for C++ base
221   /// classes. This is used while creating debug info entry for a
222   /// Record.
223   void CollectCXXBases(const CXXRecordDecl *Decl, llvm::DIFile *F,
224                        SmallVectorImpl<llvm::Metadata *> &EltTys,
225                        llvm::DIType *RecordTy);
226 
227   /// A helper function to collect template parameters.
228   llvm::DINodeArray CollectTemplateParams(const TemplateParameterList *TPList,
229                                           ArrayRef<TemplateArgument> TAList,
230                                           llvm::DIFile *Unit);
231   /// A helper function to collect debug info for function template
232   /// parameters.
233   llvm::DINodeArray CollectFunctionTemplateParams(const FunctionDecl *FD,
234                                                   llvm::DIFile *Unit);
235 
236   /// A helper function to collect debug info for template
237   /// parameters.
238   llvm::DINodeArray
239   CollectCXXTemplateParams(const ClassTemplateSpecializationDecl *TS,
240                            llvm::DIFile *F);
241 
242   llvm::DIType *createFieldType(StringRef name, QualType type,
243                                 uint64_t sizeInBitsOverride, SourceLocation loc,
244                                 AccessSpecifier AS, uint64_t offsetInBits,
245                                 llvm::DIFile *tunit, llvm::DIScope *scope,
246                                 const RecordDecl *RD = nullptr);
247 
248   /// Helpers for collecting fields of a record.
249   /// @{
250   void CollectRecordLambdaFields(const CXXRecordDecl *CXXDecl,
251                                  SmallVectorImpl<llvm::Metadata *> &E,
252                                  llvm::DIType *RecordTy);
253   llvm::DIDerivedType *CreateRecordStaticField(const VarDecl *Var,
254                                                llvm::DIType *RecordTy,
255                                                const RecordDecl *RD);
256   void CollectRecordNormalField(const FieldDecl *Field, uint64_t OffsetInBits,
257                                 llvm::DIFile *F,
258                                 SmallVectorImpl<llvm::Metadata *> &E,
259                                 llvm::DIType *RecordTy, const RecordDecl *RD);
260   void CollectRecordFields(const RecordDecl *Decl, llvm::DIFile *F,
261                            SmallVectorImpl<llvm::Metadata *> &E,
262                            llvm::DICompositeType *RecordTy);
263 
264   /// If the C++ class has vtable info then insert appropriate debug
265   /// info entry in EltTys vector.
266   void CollectVTableInfo(const CXXRecordDecl *Decl, llvm::DIFile *F,
267                          SmallVectorImpl<llvm::Metadata *> &EltTys);
268   /// @}
269 
270   /// Create a new lexical block node and push it on the stack.
271   void CreateLexicalBlock(SourceLocation Loc);
272 
273 public:
274   CGDebugInfo(CodeGenModule &CGM);
275   ~CGDebugInfo();
276 
277   void finalize();
278 
279   /// Set the main CU's DwoId field to \p Signature.
280   void setDwoId(uint64_t Signature);
281 
282   /// When generating debug information for a clang module or
283   /// precompiled header, this module map will be used to determine
284   /// the module of origin of each Decl.
285   void setModuleMap(ModuleMap &MMap) { ClangModuleMap = &MMap; }
286 
287   /// Update the current source location. If \arg loc is invalid it is
288   /// ignored.
289   void setLocation(SourceLocation Loc);
290 
291   /// Emit metadata to indicate a change in line/column information in
292   /// the source file. If the location is invalid, the previous
293   /// location will be reused.
294   void EmitLocation(CGBuilderTy &Builder, SourceLocation Loc);
295 
296   /// Emit a call to llvm.dbg.function.start to indicate
297   /// start of a new function.
298   /// \param Loc       The location of the function header.
299   /// \param ScopeLoc  The location of the function body.
300   void EmitFunctionStart(GlobalDecl GD, SourceLocation Loc,
301                          SourceLocation ScopeLoc, QualType FnType,
302                          llvm::Function *Fn, CGBuilderTy &Builder);
303 
304   /// Emit debug info for a function declaration.
305   void EmitFunctionDecl(GlobalDecl GD, SourceLocation Loc, QualType FnType);
306 
307   /// Constructs the debug code for exiting a function.
308   void EmitFunctionEnd(CGBuilderTy &Builder);
309 
310   /// Emit metadata to indicate the beginning of a new lexical block
311   /// and push the block onto the stack.
312   void EmitLexicalBlockStart(CGBuilderTy &Builder, SourceLocation Loc);
313 
314   /// Emit metadata to indicate the end of a new lexical block and pop
315   /// the current block.
316   void EmitLexicalBlockEnd(CGBuilderTy &Builder, SourceLocation Loc);
317 
318   /// Emit call to \c llvm.dbg.declare for an automatic variable
319   /// declaration.
320   void EmitDeclareOfAutoVariable(const VarDecl *Decl, llvm::Value *AI,
321                                  CGBuilderTy &Builder);
322 
323   /// Emit call to \c llvm.dbg.declare for an imported variable
324   /// declaration in a block.
325   void EmitDeclareOfBlockDeclRefVariable(const VarDecl *variable,
326                                          llvm::Value *storage,
327                                          CGBuilderTy &Builder,
328                                          const CGBlockInfo &blockInfo,
329                                          llvm::Instruction *InsertPoint = 0);
330 
331   /// Emit call to \c llvm.dbg.declare for an argument variable
332   /// declaration.
333   void EmitDeclareOfArgVariable(const VarDecl *Decl, llvm::Value *AI,
334                                 unsigned ArgNo, CGBuilderTy &Builder);
335 
336   /// Emit call to \c llvm.dbg.declare for the block-literal argument
337   /// to a block invocation function.
338   void EmitDeclareOfBlockLiteralArgVariable(const CGBlockInfo &block,
339                                             llvm::Value *Arg, unsigned ArgNo,
340                                             llvm::Value *LocalAddr,
341                                             CGBuilderTy &Builder);
342 
343   /// Emit information about a global variable.
344   void EmitGlobalVariable(llvm::GlobalVariable *GV, const VarDecl *Decl);
345 
346   /// Emit global variable's debug info.
347   void EmitGlobalVariable(const ValueDecl *VD, llvm::Constant *Init);
348 
349   /// Emit C++ using directive.
350   void EmitUsingDirective(const UsingDirectiveDecl &UD);
351 
352   /// Emit the type explicitly casted to.
353   void EmitExplicitCastType(QualType Ty);
354 
355   /// Emit C++ using declaration.
356   void EmitUsingDecl(const UsingDecl &UD);
357 
358   /// Emit an @import declaration.
359   void EmitImportDecl(const ImportDecl &ID);
360 
361   /// Emit C++ namespace alias.
362   llvm::DIImportedEntity *EmitNamespaceAlias(const NamespaceAliasDecl &NA);
363 
364   /// Emit record type's standalone debug info.
365   llvm::DIType *getOrCreateRecordType(QualType Ty, SourceLocation L);
366 
367   /// Emit an Objective-C interface type standalone debug info.
368   llvm::DIType *getOrCreateInterfaceType(QualType Ty, SourceLocation Loc);
369 
370   /// Emit standalone debug info for a type.
371   llvm::DIType *getOrCreateStandaloneType(QualType Ty, SourceLocation Loc);
372 
373   void completeType(const EnumDecl *ED);
374   void completeType(const RecordDecl *RD);
375   void completeRequiredType(const RecordDecl *RD);
376   void completeClassData(const RecordDecl *RD);
377 
378   void completeTemplateDefinition(const ClassTemplateSpecializationDecl &SD);
379 
380 private:
381   /// Emit call to llvm.dbg.declare for a variable declaration.
382   void EmitDeclare(const VarDecl *decl, llvm::Value *AI,
383                    llvm::Optional<unsigned> ArgNo, CGBuilderTy &Builder);
384 
385   /// Build up structure info for the byref.  See \a BuildByRefType.
386   llvm::DIType *EmitTypeForVarWithBlocksAttr(const VarDecl *VD,
387                                              uint64_t *OffSet);
388 
389   /// Get context info for the DeclContext of \p Decl.
390   llvm::DIScope *getDeclContextDescriptor(const Decl *D);
391   /// Get context info for a given DeclContext \p Decl.
392   llvm::DIScope *getContextDescriptor(const Decl *Context,
393                                       llvm::DIScope *Default);
394 
395   llvm::DIScope *getCurrentContextDescriptor(const Decl *Decl);
396 
397   /// Create a forward decl for a RecordType in a given context.
398   llvm::DICompositeType *getOrCreateRecordFwdDecl(const RecordType *,
399                                                   llvm::DIScope *);
400 
401   /// Return current directory name.
402   StringRef getCurrentDirname();
403 
404   /// Create new compile unit.
405   void CreateCompileUnit();
406 
407   /// Get the file debug info descriptor for the input location.
408   llvm::DIFile *getOrCreateFile(SourceLocation Loc);
409 
410   /// Get the file info for main compile unit.
411   llvm::DIFile *getOrCreateMainFile();
412 
413   /// Get the type from the cache or create a new type if necessary.
414   llvm::DIType *getOrCreateType(QualType Ty, llvm::DIFile *Fg);
415 
416   /// Get a reference to a clang module.  If \p CreateSkeletonCU is true,
417   /// this also creates a split dwarf skeleton compile unit.
418   llvm::DIModule *
419   getOrCreateModuleRef(ExternalASTSource::ASTSourceDescriptor Mod,
420                        bool CreateSkeletonCU);
421 
422   /// DebugTypeExtRefs: If \p D originated in a clang module, return it.
423   llvm::DIModule *getParentModuleOrNull(const Decl *D);
424 
425   /// Get the type from the cache or create a new partial type if
426   /// necessary.
427   llvm::DICompositeType *getOrCreateLimitedType(const RecordType *Ty,
428                                                 llvm::DIFile *F);
429 
430   /// Create type metadata for a source language type.
431   llvm::DIType *CreateTypeNode(QualType Ty, llvm::DIFile *Fg);
432 
433   /// Return the underlying ObjCInterfaceDecl if \arg Ty is an
434   /// ObjCInterface or a pointer to one.
435   ObjCInterfaceDecl *getObjCInterfaceDecl(QualType Ty);
436 
437   /// Create new member and increase Offset by FType's size.
438   llvm::DIType *CreateMemberType(llvm::DIFile *Unit, QualType FType,
439                                  StringRef Name, uint64_t *Offset);
440 
441   /// Retrieve the DIDescriptor, if any, for the canonical form of this
442   /// declaration.
443   llvm::DINode *getDeclarationOrDefinition(const Decl *D);
444 
445   /// \return debug info descriptor to describe method
446   /// declaration for the given method definition.
447   llvm::DISubprogram *getFunctionDeclaration(const Decl *D);
448 
449   /// \return debug info descriptor to describe in-class static data
450   /// member declaration for the given out-of-class definition.  If D
451   /// is an out-of-class definition of a static data member of a
452   /// class, find its corresponding in-class declaration.
453   llvm::DIDerivedType *
454   getOrCreateStaticDataMemberDeclarationOrNull(const VarDecl *D);
455 
456   /// Create a subprogram describing the forward declaration
457   /// represented in the given FunctionDecl.
458   llvm::DISubprogram *getFunctionForwardDeclaration(const FunctionDecl *FD);
459 
460   /// Create a global variable describing the forward decalration
461   /// represented in the given VarDecl.
462   llvm::DIGlobalVariable *
463   getGlobalVariableForwardDeclaration(const VarDecl *VD);
464 
465   /// \brief Return a global variable that represents one of the
466   /// collection of global variables created for an anonmyous union.
467   ///
468   /// Recursively collect all of the member fields of a global
469   /// anonymous decl and create static variables for them. The first
470   /// time this is called it needs to be on a union and then from
471   /// there we can have additional unnamed fields.
472   llvm::DIGlobalVariable *
473   CollectAnonRecordDecls(const RecordDecl *RD, llvm::DIFile *Unit,
474                          unsigned LineNo, StringRef LinkageName,
475                          llvm::GlobalVariable *Var, llvm::DIScope *DContext);
476 
477   /// Get function name for the given FunctionDecl. If the name is
478   /// constructed on demand (e.g., C++ destructor) then the name is
479   /// stored on the side.
480   StringRef getFunctionName(const FunctionDecl *FD);
481 
482   /// Returns the unmangled name of an Objective-C method.
483   /// This is the display name for the debugging info.
484   StringRef getObjCMethodName(const ObjCMethodDecl *FD);
485 
486   /// Return selector name. This is used for debugging
487   /// info.
488   StringRef getSelectorName(Selector S);
489 
490   /// Get class name including template argument list.
491   StringRef getClassName(const RecordDecl *RD);
492 
493   /// Get the vtable name for the given class.
494   StringRef getVTableName(const CXXRecordDecl *Decl);
495 
496   /// Get line number for the location. If location is invalid
497   /// then use current location.
498   unsigned getLineNumber(SourceLocation Loc);
499 
500   /// Get column number for the location. If location is
501   /// invalid then use current location.
502   /// \param Force  Assume DebugColumnInfo option is true.
503   unsigned getColumnNumber(SourceLocation Loc, bool Force = false);
504 
505   /// Collect various properties of a FunctionDecl.
506   /// \param GD  A GlobalDecl whose getDecl() must return a FunctionDecl.
507   void collectFunctionDeclProps(GlobalDecl GD, llvm::DIFile *Unit,
508                                 StringRef &Name, StringRef &LinkageName,
509                                 llvm::DIScope *&FDContext,
510                                 llvm::DINodeArray &TParamsArray,
511                                 unsigned &Flags);
512 
513   /// Collect various properties of a VarDecl.
514   void collectVarDeclProps(const VarDecl *VD, llvm::DIFile *&Unit,
515                            unsigned &LineNo, QualType &T, StringRef &Name,
516                            StringRef &LinkageName, llvm::DIScope *&VDContext);
517 
518   /// Allocate a copy of \p A using the DebugInfoNames allocator
519   /// and return a reference to it. If multiple arguments are given the strings
520   /// are concatenated.
521   StringRef internString(StringRef A, StringRef B = StringRef()) {
522     char *Data = DebugInfoNames.Allocate<char>(A.size() + B.size());
523     if (!A.empty())
524       std::memcpy(Data, A.data(), A.size());
525     if (!B.empty())
526       std::memcpy(Data + A.size(), B.data(), B.size());
527     return StringRef(Data, A.size() + B.size());
528   }
529 };
530 
531 /// A scoped helper to set the current debug location to the specified
532 /// location or preferred location of the specified Expr.
533 class ApplyDebugLocation {
534 private:
535   void init(SourceLocation TemporaryLocation, bool DefaultToEmpty = false);
536   ApplyDebugLocation(CodeGenFunction &CGF, bool DefaultToEmpty,
537                      SourceLocation TemporaryLocation);
538 
539   llvm::DebugLoc OriginalLocation;
540   CodeGenFunction *CGF;
541 
542 public:
543   /// Set the location to the (valid) TemporaryLocation.
544   ApplyDebugLocation(CodeGenFunction &CGF, SourceLocation TemporaryLocation);
545   ApplyDebugLocation(CodeGenFunction &CGF, const Expr *E);
546   ApplyDebugLocation(CodeGenFunction &CGF, llvm::DebugLoc Loc);
547   ApplyDebugLocation(ApplyDebugLocation &&Other) : CGF(Other.CGF) {
548     Other.CGF = nullptr;
549   }
550 
551   ~ApplyDebugLocation();
552 
553   /// \brief Apply TemporaryLocation if it is valid. Otherwise switch
554   /// to an artificial debug location that has a valid scope, but no
555   /// line information.
556   ///
557   /// Artificial locations are useful when emitting compiler-generated
558   /// helper functions that have no source location associated with
559   /// them. The DWARF specification allows the compiler to use the
560   /// special line number 0 to indicate code that can not be
561   /// attributed to any source location. Note that passing an empty
562   /// SourceLocation to CGDebugInfo::setLocation() will result in the
563   /// last valid location being reused.
564   static ApplyDebugLocation CreateArtificial(CodeGenFunction &CGF) {
565     return ApplyDebugLocation(CGF, false, SourceLocation());
566   }
567   /// \brief Apply TemporaryLocation if it is valid. Otherwise switch
568   /// to an artificial debug location that has a valid scope, but no
569   /// line information.
570   static ApplyDebugLocation
571   CreateDefaultArtificial(CodeGenFunction &CGF,
572                           SourceLocation TemporaryLocation) {
573     return ApplyDebugLocation(CGF, false, TemporaryLocation);
574   }
575 
576   /// Set the IRBuilder to not attach debug locations.  Note that
577   /// passing an empty SourceLocation to \a CGDebugInfo::setLocation()
578   /// will result in the last valid location being reused.  Note that
579   /// all instructions that do not have a location at the beginning of
580   /// a function are counted towards to funciton prologue.
581   static ApplyDebugLocation CreateEmpty(CodeGenFunction &CGF) {
582     return ApplyDebugLocation(CGF, true, SourceLocation());
583   }
584 
585   /// \brief Apply TemporaryLocation if it is valid. Otherwise set the IRBuilder
586   /// to not attach debug locations.
587   static ApplyDebugLocation
588   CreateDefaultEmpty(CodeGenFunction &CGF, SourceLocation TemporaryLocation) {
589     return ApplyDebugLocation(CGF, true, TemporaryLocation);
590   }
591 };
592 
593 } // namespace CodeGen
594 } // namespace clang
595 
596 #endif
597