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