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 /// CGDebugInfo - This class gathers all debug information during compilation
47 /// and is responsible for emitting to llvm globals or pass directly to
48 /// the backend.
49 class CGDebugInfo {
50   friend class ArtificialLocation;
51   friend class SaveAndRestoreLocation;
52   CodeGenModule &CGM;
53   const CodeGenOptions::DebugInfoKind DebugKind;
54   llvm::DIBuilder DBuilder;
55   llvm::DICompileUnit TheCU;
56   SourceLocation CurLoc, PrevLoc;
57   llvm::DIType VTablePtrType;
58   llvm::DIType ClassTy;
59   llvm::DICompositeType ObjTy;
60   llvm::DIType SelTy;
61   llvm::DIType OCLImage1dDITy, OCLImage1dArrayDITy, OCLImage1dBufferDITy;
62   llvm::DIType OCLImage2dDITy, OCLImage2dArrayDITy;
63   llvm::DIType OCLImage3dDITy;
64   llvm::DIType OCLEventDITy;
65   llvm::DIType BlockLiteralGeneric;
66 
67   /// TypeCache - Cache of previously constructed Types.
68   llvm::DenseMap<const void *, llvm::WeakVH> TypeCache;
69 
70   struct ObjCInterfaceCacheEntry {
71     const ObjCInterfaceType *Type;
72     llvm::DIType Decl;
73     llvm::DIFile Unit;
74     ObjCInterfaceCacheEntry(const ObjCInterfaceType *Type, llvm::DIType Decl,
75                             llvm::DIFile Unit)
76         : Type(Type), Decl(Decl), Unit(Unit) {}
77   };
78 
79   /// ObjCInterfaceCache - Cache of previously constructed interfaces
80   /// which may change.
81   llvm::SmallVector<ObjCInterfaceCacheEntry, 32> ObjCInterfaceCache;
82 
83   /// RetainedTypes - list of interfaces we want to keep even if orphaned.
84   std::vector<void *> RetainedTypes;
85 
86   /// ReplaceMap - Cache of forward declared types to RAUW at the end of
87   /// compilation.
88   std::vector<std::pair<const TagType *, llvm::WeakVH>> ReplaceMap;
89 
90   /// \brief Cache of replaceable forward declarartions (functions and
91   /// variables) to RAUW at the end of compilation.
92   std::vector<std::pair<const DeclaratorDecl *, llvm::WeakVH>> FwdDeclReplaceMap;
93 
94   // LexicalBlockStack - Keep track of our current nested lexical block.
95   std::vector<llvm::TrackingVH<llvm::MDNode> > LexicalBlockStack;
96   llvm::DenseMap<const Decl *, llvm::WeakVH> RegionMap;
97   // FnBeginRegionCount - Keep track of LexicalBlockStack counter at the
98   // beginning of a function. This is used to pop unbalanced regions at
99   // the end of a function.
100   std::vector<unsigned> FnBeginRegionCount;
101 
102   /// DebugInfoNames - This is a storage for names that are
103   /// constructed on demand. For example, C++ destructors, C++ operators etc..
104   llvm::BumpPtrAllocator DebugInfoNames;
105   StringRef CWDName;
106 
107   llvm::DenseMap<const char *, llvm::WeakVH> DIFileCache;
108   llvm::DenseMap<const FunctionDecl *, llvm::WeakVH> SPCache;
109   /// \brief Cache declarations relevant to DW_TAG_imported_declarations (C++
110   /// using declarations) that aren't covered by other more specific caches.
111   llvm::DenseMap<const Decl *, llvm::WeakVH> DeclCache;
112   llvm::DenseMap<const NamespaceDecl *, llvm::WeakVH> NameSpaceCache;
113   llvm::DenseMap<const NamespaceAliasDecl *, llvm::WeakVH> NamespaceAliasCache;
114   llvm::DenseMap<const Decl *, llvm::WeakVH> StaticDataMemberCache;
115 
116   /// Helper functions for getOrCreateType.
117   unsigned Checksum(const ObjCInterfaceDecl *InterfaceDecl);
118   llvm::DIType CreateType(const BuiltinType *Ty);
119   llvm::DIType CreateType(const ComplexType *Ty);
120   llvm::DIType CreateQualifiedType(QualType Ty, llvm::DIFile Fg);
121   llvm::DIType CreateType(const TypedefType *Ty, llvm::DIFile Fg);
122   llvm::DIType CreateType(const TemplateSpecializationType *Ty, llvm::DIFile Fg);
123   llvm::DIType CreateType(const ObjCObjectPointerType *Ty,
124                           llvm::DIFile F);
125   llvm::DIType CreateType(const PointerType *Ty, llvm::DIFile F);
126   llvm::DIType CreateType(const BlockPointerType *Ty, llvm::DIFile F);
127   llvm::DIType CreateType(const FunctionType *Ty, llvm::DIFile F);
128   llvm::DIType CreateType(const RecordType *Tyg);
129   llvm::DIType CreateTypeDefinition(const RecordType *Ty);
130   llvm::DICompositeType CreateLimitedType(const RecordType *Ty);
131   void CollectContainingType(const CXXRecordDecl *RD, llvm::DICompositeType CT);
132   llvm::DIType CreateType(const ObjCInterfaceType *Ty, llvm::DIFile F);
133   llvm::DIType CreateTypeDefinition(const ObjCInterfaceType *Ty, llvm::DIFile F);
134   llvm::DIType CreateType(const ObjCObjectType *Ty, llvm::DIFile F);
135   llvm::DIType CreateType(const VectorType *Ty, llvm::DIFile F);
136   llvm::DIType CreateType(const ArrayType *Ty, llvm::DIFile F);
137   llvm::DIType CreateType(const LValueReferenceType *Ty, llvm::DIFile F);
138   llvm::DIType CreateType(const RValueReferenceType *Ty, llvm::DIFile Unit);
139   llvm::DIType CreateType(const MemberPointerType *Ty, llvm::DIFile F);
140   llvm::DIType CreateType(const AtomicType *Ty, llvm::DIFile F);
141   llvm::DIType CreateEnumType(const EnumType *Ty);
142   llvm::DIType CreateTypeDefinition(const EnumType *Ty);
143   llvm::DIType CreateSelfType(const QualType &QualTy, llvm::DIType Ty);
144   llvm::DIType getTypeOrNull(const QualType);
145   llvm::DICompositeType getOrCreateMethodType(const CXXMethodDecl *Method,
146                                               llvm::DIFile F);
147   llvm::DICompositeType getOrCreateInstanceMethodType(
148       QualType ThisPtr, const FunctionProtoType *Func, llvm::DIFile Unit);
149   llvm::DICompositeType getOrCreateFunctionType(const Decl *D, QualType FnType,
150                                                 llvm::DIFile F);
151   llvm::DIType getOrCreateVTablePtrType(llvm::DIFile F);
152   llvm::DINameSpace getOrCreateNameSpace(const NamespaceDecl *N);
153   llvm::DIType getOrCreateTypeDeclaration(QualType PointeeTy, llvm::DIFile F);
154   llvm::DIType CreatePointerLikeType(llvm::dwarf::Tag Tag,
155                                      const Type *Ty, QualType PointeeTy,
156                                      llvm::DIFile F);
157 
158   llvm::Value *getCachedInterfaceTypeOrNull(const QualType Ty);
159   llvm::DIType getOrCreateStructPtrType(StringRef Name, llvm::DIType &Cache);
160 
161   llvm::DISubprogram CreateCXXMemberFunction(const CXXMethodDecl *Method,
162                                              llvm::DIFile F,
163                                              llvm::DIType RecordTy);
164 
165   void CollectCXXMemberFunctions(const CXXRecordDecl *Decl,
166                                  llvm::DIFile F,
167                                  SmallVectorImpl<llvm::Value *> &E,
168                                  llvm::DIType T);
169 
170   void CollectCXXBases(const CXXRecordDecl *Decl,
171                        llvm::DIFile F,
172                        SmallVectorImpl<llvm::Value *> &EltTys,
173                        llvm::DIType RecordTy);
174 
175   llvm::DIArray
176   CollectTemplateParams(const TemplateParameterList *TPList,
177                         ArrayRef<TemplateArgument> TAList,
178                         llvm::DIFile Unit);
179   llvm::DIArray
180   CollectFunctionTemplateParams(const FunctionDecl *FD, llvm::DIFile Unit);
181   llvm::DIArray
182   CollectCXXTemplateParams(const ClassTemplateSpecializationDecl *TS,
183                            llvm::DIFile F);
184 
185   llvm::DIType createFieldType(StringRef name, QualType type,
186                                uint64_t sizeInBitsOverride, SourceLocation loc,
187                                AccessSpecifier AS,
188                                uint64_t offsetInBits,
189                                llvm::DIFile tunit,
190                                llvm::DIScope scope,
191                                const RecordDecl* RD = nullptr);
192 
193   // Helpers for collecting fields of a record.
194   void CollectRecordLambdaFields(const CXXRecordDecl *CXXDecl,
195                                  SmallVectorImpl<llvm::Value *> &E,
196                                  llvm::DIType RecordTy);
197   llvm::DIDerivedType CreateRecordStaticField(const VarDecl *Var,
198                                               llvm::DIType RecordTy,
199                                               const RecordDecl* RD);
200   void CollectRecordNormalField(const FieldDecl *Field, uint64_t OffsetInBits,
201                                 llvm::DIFile F,
202                                 SmallVectorImpl<llvm::Value *> &E,
203                                 llvm::DIType RecordTy,
204                                 const RecordDecl* RD);
205   void CollectRecordFields(const RecordDecl *Decl, llvm::DIFile F,
206                            SmallVectorImpl<llvm::Value *> &E,
207                            llvm::DICompositeType RecordTy);
208 
209   void CollectVTableInfo(const CXXRecordDecl *Decl,
210                          llvm::DIFile F,
211                          SmallVectorImpl<llvm::Value *> &EltTys);
212 
213   // CreateLexicalBlock - Create a new lexical block node and push it on
214   // the stack.
215   void CreateLexicalBlock(SourceLocation Loc);
216 
217 public:
218   CGDebugInfo(CodeGenModule &CGM);
219   ~CGDebugInfo();
220 
221   void finalize();
222 
223   /// setLocation - Update the current source location. If \arg loc is
224   /// invalid it is ignored.
225   void setLocation(SourceLocation Loc);
226 
227   /// getLocation - Return the current source location.
228   SourceLocation getLocation() const { return CurLoc; }
229 
230   /// EmitLocation - Emit metadata to indicate a change in line/column
231   /// information in the source file.
232   /// \param ForceColumnInfo  Assume DebugColumnInfo option is true.
233   void EmitLocation(CGBuilderTy &Builder, SourceLocation Loc,
234                     bool ForceColumnInfo = false);
235 
236   /// EmitFunctionStart - Emit a call to llvm.dbg.function.start to indicate
237   /// start of a new function.
238   /// \param Loc       The location of the function header.
239   /// \param ScopeLoc  The location of the function body.
240   void EmitFunctionStart(GlobalDecl GD,
241                          SourceLocation Loc, SourceLocation ScopeLoc,
242                          QualType FnType, llvm::Function *Fn,
243                          CGBuilderTy &Builder);
244 
245   /// EmitFunctionEnd - Constructs the debug code for exiting a function.
246   void EmitFunctionEnd(CGBuilderTy &Builder);
247 
248   /// EmitLexicalBlockStart - Emit metadata to indicate the beginning of a
249   /// new lexical block and push the block onto the stack.
250   void EmitLexicalBlockStart(CGBuilderTy &Builder, SourceLocation Loc);
251 
252   /// EmitLexicalBlockEnd - Emit metadata to indicate the end of a new lexical
253   /// block and pop the current block.
254   void EmitLexicalBlockEnd(CGBuilderTy &Builder, SourceLocation Loc);
255 
256   /// EmitDeclareOfAutoVariable - Emit call to llvm.dbg.declare for an automatic
257   /// variable declaration.
258   void EmitDeclareOfAutoVariable(const VarDecl *Decl, llvm::Value *AI,
259                                  CGBuilderTy &Builder);
260 
261   /// EmitDeclareOfBlockDeclRefVariable - Emit call to llvm.dbg.declare for an
262   /// imported variable declaration in a block.
263   void EmitDeclareOfBlockDeclRefVariable(const VarDecl *variable,
264                                          llvm::Value *storage,
265                                          CGBuilderTy &Builder,
266                                          const CGBlockInfo &blockInfo,
267                                          llvm::Instruction *InsertPoint = 0);
268 
269   /// EmitDeclareOfArgVariable - Emit call to llvm.dbg.declare for an argument
270   /// variable declaration.
271   void EmitDeclareOfArgVariable(const VarDecl *Decl, llvm::Value *AI,
272                                 unsigned ArgNo, CGBuilderTy &Builder);
273 
274   /// EmitDeclareOfBlockLiteralArgVariable - Emit call to
275   /// llvm.dbg.declare for the block-literal argument to a block
276   /// invocation function.
277   void EmitDeclareOfBlockLiteralArgVariable(const CGBlockInfo &block,
278                                             llvm::Value *Arg, unsigned ArgNo,
279                                             llvm::Value *LocalAddr,
280                                             CGBuilderTy &Builder);
281 
282   /// EmitGlobalVariable - Emit information about a global variable.
283   void EmitGlobalVariable(llvm::GlobalVariable *GV, const VarDecl *Decl);
284 
285   /// EmitGlobalVariable - Emit global variable's debug info.
286   void EmitGlobalVariable(const ValueDecl *VD, llvm::Constant *Init);
287 
288   /// \brief - Emit C++ using directive.
289   void EmitUsingDirective(const UsingDirectiveDecl &UD);
290 
291   /// EmitExplicitCastType - Emit the type explicitly casted to.
292   void EmitExplicitCastType(QualType Ty);
293 
294   /// \brief - Emit C++ using declaration.
295   void EmitUsingDecl(const UsingDecl &UD);
296 
297   /// \brief - Emit C++ namespace alias.
298   llvm::DIImportedEntity EmitNamespaceAlias(const NamespaceAliasDecl &NA);
299 
300   /// getOrCreateRecordType - Emit record type's standalone debug info.
301   llvm::DIType getOrCreateRecordType(QualType Ty, SourceLocation L);
302 
303   /// getOrCreateInterfaceType - Emit an objective c interface type standalone
304   /// debug info.
305   llvm::DIType getOrCreateInterfaceType(QualType Ty,
306                                         SourceLocation Loc);
307 
308   void completeType(const EnumDecl *ED);
309   void completeType(const RecordDecl *RD);
310   void completeRequiredType(const RecordDecl *RD);
311   void completeClassData(const RecordDecl *RD);
312 
313   void completeTemplateDefinition(const ClassTemplateSpecializationDecl &SD);
314 
315 private:
316   /// EmitDeclare - Emit call to llvm.dbg.declare for a variable declaration.
317   /// Tag accepts custom types DW_TAG_arg_variable and DW_TAG_auto_variable,
318   /// otherwise would be of type llvm::dwarf::Tag.
319   void EmitDeclare(const VarDecl *decl, llvm::dwarf::LLVMConstants Tag,
320                    llvm::Value *AI, unsigned ArgNo, CGBuilderTy &Builder);
321 
322   // EmitTypeForVarWithBlocksAttr - Build up structure info for the byref.
323   // See BuildByRefType.
324   llvm::DIType EmitTypeForVarWithBlocksAttr(const VarDecl *VD,
325                                             uint64_t *OffSet);
326 
327   /// getContextDescriptor - Get context info for the decl.
328   llvm::DIScope getContextDescriptor(const Decl *Decl);
329 
330   llvm::DIScope getCurrentContextDescriptor(const Decl *Decl);
331 
332   /// \brief Create a forward decl for a RecordType in a given context.
333   llvm::DICompositeType getOrCreateRecordFwdDecl(const RecordType *,
334                                                  llvm::DIDescriptor);
335 
336   /// createContextChain - Create a set of decls for the context chain.
337   llvm::DIDescriptor createContextChain(const Decl *Decl);
338 
339   /// getCurrentDirname - Return current directory name.
340   StringRef getCurrentDirname();
341 
342   /// CreateCompileUnit - Create new compile unit.
343   void CreateCompileUnit();
344 
345   /// getOrCreateFile - Get the file debug info descriptor for the input
346   /// location.
347   llvm::DIFile getOrCreateFile(SourceLocation Loc);
348 
349   /// getOrCreateMainFile - Get the file info for main compile unit.
350   llvm::DIFile getOrCreateMainFile();
351 
352   /// getOrCreateType - Get the type from the cache or create a new type if
353   /// necessary.
354   llvm::DIType getOrCreateType(QualType Ty, llvm::DIFile Fg);
355 
356   /// getOrCreateLimitedType - Get the type from the cache or create a new
357   /// partial type if necessary.
358   llvm::DIType getOrCreateLimitedType(const RecordType *Ty, llvm::DIFile F);
359 
360   /// CreateTypeNode - Create type metadata for a source language type.
361   llvm::DIType CreateTypeNode(QualType Ty, llvm::DIFile Fg);
362 
363   /// getObjCInterfaceDecl - return the underlying ObjCInterfaceDecl
364   /// if Ty is an ObjCInterface or a pointer to one.
365   ObjCInterfaceDecl* getObjCInterfaceDecl(QualType Ty);
366 
367   /// CreateMemberType - Create new member and increase Offset by FType's size.
368   llvm::DIType CreateMemberType(llvm::DIFile Unit, QualType FType,
369                                 StringRef Name, uint64_t *Offset);
370 
371   /// \brief Retrieve the DIDescriptor, if any, for the canonical form of this
372   /// declaration.
373   llvm::DIDescriptor getDeclarationOrDefinition(const Decl *D);
374 
375   /// getFunctionDeclaration - Return debug info descriptor to describe method
376   /// declaration for the given method definition.
377   llvm::DISubprogram getFunctionDeclaration(const Decl *D);
378 
379   /// Return debug info descriptor to describe in-class static data member
380   /// declaration for the given out-of-class definition.
381   llvm::DIDerivedType
382   getOrCreateStaticDataMemberDeclarationOrNull(const VarDecl *D);
383 
384   /// \brief Create a DISubprogram describing the forward
385   /// decalration represented in the given FunctionDecl.
386   llvm::DISubprogram getFunctionForwardDeclaration(const FunctionDecl *FD);
387 
388   /// \brief Create a DIGlobalVariable describing the forward
389   /// decalration represented in the given VarDecl.
390   llvm::DIGlobalVariable getGlobalVariableForwardDeclaration(const VarDecl *VD);
391 
392   /// Return a global variable that represents one of the collection of
393   /// global variables created for an anonmyous union.
394   llvm::DIGlobalVariable
395   CollectAnonRecordDecls(const RecordDecl *RD, llvm::DIFile Unit, unsigned LineNo,
396                          StringRef LinkageName, llvm::GlobalVariable *Var,
397                          llvm::DIDescriptor DContext);
398 
399   /// getFunctionName - Get function name for the given FunctionDecl. If the
400   /// name is constructed on demand (e.g. C++ destructor) then the name
401   /// is stored on the side.
402   StringRef getFunctionName(const FunctionDecl *FD);
403 
404   /// getObjCMethodName - Returns the unmangled name of an Objective-C method.
405   /// This is the display name for the debugging info.
406   StringRef getObjCMethodName(const ObjCMethodDecl *FD);
407 
408   /// getSelectorName - Return selector name. This is used for debugging
409   /// info.
410   StringRef getSelectorName(Selector S);
411 
412   /// getClassName - Get class name including template argument list.
413   StringRef getClassName(const RecordDecl *RD);
414 
415   /// getVTableName - Get vtable name for the given Class.
416   StringRef getVTableName(const CXXRecordDecl *Decl);
417 
418   /// getLineNumber - Get line number for the location. If location is invalid
419   /// then use current location.
420   unsigned getLineNumber(SourceLocation Loc);
421 
422   /// getColumnNumber - Get column number for the location. If location is
423   /// invalid then use current location.
424   /// \param Force  Assume DebugColumnInfo option is true.
425   unsigned getColumnNumber(SourceLocation Loc, bool Force=false);
426 
427   /// \brief Collect various properties of a FunctionDecl.
428   /// \param GD  A GlobalDecl whose getDecl() must return a FunctionDecl.
429   void collectFunctionDeclProps(GlobalDecl GD,
430                                 llvm::DIFile Unit,
431                                 StringRef &Name, StringRef &LinkageName,
432                                 llvm::DIDescriptor &FDContext,
433                                 llvm::DIArray &TParamsArray,
434                                 unsigned &Flags);
435 
436   /// \brief Collect various properties of a VarDecl.
437   void collectVarDeclProps(const VarDecl *VD, llvm::DIFile &Unit,
438                            unsigned &LineNo, QualType &T,
439                            StringRef &Name, StringRef &LinkageName,
440                            llvm::DIDescriptor &VDContext);
441 
442   /// internString - Allocate a copy of \p A using the DebugInfoNames allocator
443   /// and return a reference to it. If multiple arguments are given the strings
444   /// are concatenated.
445   StringRef internString(StringRef A, StringRef B = StringRef()) {
446     char *Data = DebugInfoNames.Allocate<char>(A.size() + B.size());
447     std::memcpy(Data, A.data(), A.size());
448     std::memcpy(Data + A.size(), B.data(), B.size());
449     return StringRef(Data, A.size() + B.size());
450   }
451 };
452 
453 /// SaveAndRestoreLocation - An RAII object saves the current location
454 /// and automatically restores it to the original value.
455 class SaveAndRestoreLocation {
456 protected:
457   SourceLocation SavedLoc;
458   CGDebugInfo *DI;
459   CGBuilderTy &Builder;
460 public:
461   SaveAndRestoreLocation(CodeGenFunction &CGF, CGBuilderTy &B);
462   /// Autorestore everything back to normal.
463   ~SaveAndRestoreLocation();
464 };
465 
466 /// NoLocation - An RAII object that temporarily disables debug
467 /// locations. This is useful for emitting instructions that should be
468 /// counted towards the function prologue.
469 class NoLocation : public SaveAndRestoreLocation {
470 public:
471   NoLocation(CodeGenFunction &CGF, CGBuilderTy &B);
472   /// Autorestore everything back to normal.
473   ~NoLocation();
474 };
475 
476 /// ArtificialLocation - An RAII object that temporarily switches to
477 /// an artificial debug location that has a valid scope, but no line
478 /// information. This is useful when emitting compiler-generated
479 /// helper functions that have no source location associated with
480 /// them. The DWARF specification allows the compiler to use the
481 /// special line number 0 to indicate code that can not be attributed
482 /// to any source location.
483 ///
484 /// This is necessary because passing an empty SourceLocation to
485 /// CGDebugInfo::setLocation() will result in the last valid location
486 /// being reused.
487 class ArtificialLocation : public SaveAndRestoreLocation {
488 public:
489   ArtificialLocation(CodeGenFunction &CGF, CGBuilderTy &B);
490 
491   /// Set the current location to line 0, but within the current scope
492   /// (= the top of the LexicalBlockStack).
493   void Emit();
494 
495   /// Autorestore everything back to normal.
496   ~ArtificialLocation();
497 };
498 
499 
500 } // namespace CodeGen
501 } // namespace clang
502 
503 
504 #endif
505