1 //===--- Mangle.h - Mangle C++ Names ----------------------------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // Defines the C++ name mangling interface.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #ifndef LLVM_CLANG_AST_MANGLE_H
14 #define LLVM_CLANG_AST_MANGLE_H
15 
16 #include "clang/AST/Decl.h"
17 #include "clang/AST/GlobalDecl.h"
18 #include "clang/AST/Type.h"
19 #include "clang/Basic/ABI.h"
20 #include "llvm/ADT/DenseMap.h"
21 #include "llvm/Support/Casting.h"
22 #include <optional>
23 
24 namespace llvm {
25   class raw_ostream;
26 }
27 
28 namespace clang {
29   class ASTContext;
30   class BlockDecl;
31   class CXXConstructorDecl;
32   class CXXDestructorDecl;
33   class CXXMethodDecl;
34   class FunctionDecl;
35   struct MethodVFTableLocation;
36   class NamedDecl;
37   class ObjCMethodDecl;
38   class StringLiteral;
39   struct ThisAdjustment;
40   struct ThunkInfo;
41   class VarDecl;
42 
43 /// MangleContext - Context for tracking state which persists across multiple
44 /// calls to the C++ name mangler.
45 class MangleContext {
46 public:
47   enum ManglerKind {
48     MK_Itanium,
49     MK_Microsoft
50   };
51 
52 private:
53   virtual void anchor();
54 
55   ASTContext &Context;
56   DiagnosticsEngine &Diags;
57   const ManglerKind Kind;
58   /// For aux target. If true, uses mangling number for aux target from
59   /// ASTContext.
60   bool IsAux = false;
61 
62   llvm::DenseMap<const BlockDecl*, unsigned> GlobalBlockIds;
63   llvm::DenseMap<const BlockDecl*, unsigned> LocalBlockIds;
64   llvm::DenseMap<const NamedDecl*, uint64_t> AnonStructIds;
65   llvm::DenseMap<const FunctionDecl*, unsigned> FuncAnonStructSize;
66 
67 public:
68   ManglerKind getKind() const { return Kind; }
69 
70   bool isAux() const { return IsAux; }
71 
72   explicit MangleContext(ASTContext &Context, DiagnosticsEngine &Diags,
73                          ManglerKind Kind, bool IsAux = false)
74       : Context(Context), Diags(Diags), Kind(Kind), IsAux(IsAux) {}
75 
76   virtual ~MangleContext() { }
77 
78   ASTContext &getASTContext() const { return Context; }
79 
80   DiagnosticsEngine &getDiags() const { return Diags; }
81 
82   virtual void startNewFunction() { LocalBlockIds.clear(); }
83 
84   unsigned getBlockId(const BlockDecl *BD, bool Local) {
85     llvm::DenseMap<const BlockDecl *, unsigned> &BlockIds
86       = Local? LocalBlockIds : GlobalBlockIds;
87     std::pair<llvm::DenseMap<const BlockDecl *, unsigned>::iterator, bool>
88       Result = BlockIds.insert(std::make_pair(BD, BlockIds.size()));
89     return Result.first->second;
90   }
91 
92   uint64_t getAnonymousStructId(const NamedDecl *D,
93                                 const FunctionDecl *FD = nullptr) {
94     auto FindResult = AnonStructIds.find(D);
95     if (FindResult != AnonStructIds.end())
96       return FindResult->second;
97 
98     // If FunctionDecl is passed in, the anonymous structID will be per-function
99     // based.
100     unsigned Id = FD ? FuncAnonStructSize[FD]++ : AnonStructIds.size();
101     std::pair<llvm::DenseMap<const NamedDecl *, uint64_t>::iterator, bool>
102         Result = AnonStructIds.insert(std::make_pair(D, Id));
103     return Result.first->second;
104   }
105 
106   uint64_t getAnonymousStructIdForDebugInfo(const NamedDecl *D) {
107     llvm::DenseMap<const NamedDecl *, uint64_t>::iterator Result =
108         AnonStructIds.find(D);
109     // The decl should already be inserted, but return 0 in case it is not.
110     if (Result == AnonStructIds.end())
111       return 0;
112     return Result->second;
113   }
114 
115   virtual std::string getLambdaString(const CXXRecordDecl *Lambda) = 0;
116 
117   /// @name Mangler Entry Points
118   /// @{
119 
120   bool shouldMangleDeclName(const NamedDecl *D);
121   virtual bool shouldMangleCXXName(const NamedDecl *D) = 0;
122   virtual bool shouldMangleStringLiteral(const StringLiteral *SL) = 0;
123 
124   virtual bool isUniqueInternalLinkageDecl(const NamedDecl *ND) {
125     return false;
126   }
127 
128   virtual void needsUniqueInternalLinkageNames() { }
129 
130   // FIXME: consider replacing raw_ostream & with something like SmallString &.
131   void mangleName(GlobalDecl GD, raw_ostream &);
132   virtual void mangleCXXName(GlobalDecl GD, raw_ostream &) = 0;
133   virtual void mangleThunk(const CXXMethodDecl *MD,
134                           const ThunkInfo &Thunk,
135                           raw_ostream &) = 0;
136   virtual void mangleCXXDtorThunk(const CXXDestructorDecl *DD, CXXDtorType Type,
137                                   const ThisAdjustment &ThisAdjustment,
138                                   raw_ostream &) = 0;
139   virtual void mangleReferenceTemporary(const VarDecl *D,
140                                         unsigned ManglingNumber,
141                                         raw_ostream &) = 0;
142   virtual void mangleCXXRTTI(QualType T, raw_ostream &) = 0;
143   virtual void mangleCXXRTTIName(QualType T, raw_ostream &) = 0;
144   virtual void mangleStringLiteral(const StringLiteral *SL, raw_ostream &) = 0;
145   virtual void mangleMSGuidDecl(const MSGuidDecl *GD, raw_ostream&);
146 
147   void mangleGlobalBlock(const BlockDecl *BD,
148                          const NamedDecl *ID,
149                          raw_ostream &Out);
150   void mangleCtorBlock(const CXXConstructorDecl *CD, CXXCtorType CT,
151                        const BlockDecl *BD, raw_ostream &Out);
152   void mangleDtorBlock(const CXXDestructorDecl *CD, CXXDtorType DT,
153                        const BlockDecl *BD, raw_ostream &Out);
154   void mangleBlock(const DeclContext *DC, const BlockDecl *BD,
155                    raw_ostream &Out);
156 
157   void mangleObjCMethodName(const ObjCMethodDecl *MD, raw_ostream &OS,
158                             bool includePrefixByte = true,
159                             bool includeCategoryNamespace = true);
160   void mangleObjCMethodNameAsSourceName(const ObjCMethodDecl *MD,
161                                         raw_ostream &);
162 
163   virtual void mangleStaticGuardVariable(const VarDecl *D, raw_ostream &) = 0;
164 
165   virtual void mangleDynamicInitializer(const VarDecl *D, raw_ostream &) = 0;
166 
167   virtual void mangleDynamicAtExitDestructor(const VarDecl *D,
168                                              raw_ostream &) = 0;
169 
170   virtual void mangleSEHFilterExpression(GlobalDecl EnclosingDecl,
171                                          raw_ostream &Out) = 0;
172 
173   virtual void mangleSEHFinallyBlock(GlobalDecl EnclosingDecl,
174                                      raw_ostream &Out) = 0;
175 
176   /// Generates a unique string for an externally visible type for use with TBAA
177   /// or type uniquing.
178   /// TODO: Extend this to internal types by generating names that are unique
179   /// across translation units so it can be used with LTO.
180   virtual void mangleTypeName(QualType T, raw_ostream &) = 0;
181 
182   /// @}
183 };
184 
185 class ItaniumMangleContext : public MangleContext {
186 public:
187   using DiscriminatorOverrideTy =
188       std::optional<unsigned> (*)(ASTContext &, const NamedDecl *);
189   explicit ItaniumMangleContext(ASTContext &C, DiagnosticsEngine &D,
190                                 bool IsAux = false)
191       : MangleContext(C, D, MK_Itanium, IsAux) {}
192 
193   virtual void mangleCXXVTable(const CXXRecordDecl *RD, raw_ostream &) = 0;
194   virtual void mangleCXXVTT(const CXXRecordDecl *RD, raw_ostream &) = 0;
195   virtual void mangleCXXCtorVTable(const CXXRecordDecl *RD, int64_t Offset,
196                                    const CXXRecordDecl *Type,
197                                    raw_ostream &) = 0;
198   virtual void mangleItaniumThreadLocalInit(const VarDecl *D,
199                                             raw_ostream &) = 0;
200   virtual void mangleItaniumThreadLocalWrapper(const VarDecl *D,
201                                                raw_ostream &) = 0;
202 
203   virtual void mangleCXXCtorComdat(const CXXConstructorDecl *D,
204                                    raw_ostream &) = 0;
205   virtual void mangleCXXDtorComdat(const CXXDestructorDecl *D,
206                                    raw_ostream &) = 0;
207 
208   virtual void mangleLambdaSig(const CXXRecordDecl *Lambda, raw_ostream &) = 0;
209 
210   virtual void mangleDynamicStermFinalizer(const VarDecl *D, raw_ostream &) = 0;
211 
212   virtual void mangleModuleInitializer(const Module *Module, raw_ostream &) = 0;
213 
214   // This has to live here, otherwise the CXXNameMangler won't have access to
215   // it.
216   virtual DiscriminatorOverrideTy getDiscriminatorOverride() const = 0;
217   static bool classof(const MangleContext *C) {
218     return C->getKind() == MK_Itanium;
219   }
220 
221   static ItaniumMangleContext *
222   create(ASTContext &Context, DiagnosticsEngine &Diags, bool IsAux = false);
223   static ItaniumMangleContext *create(ASTContext &Context,
224                                       DiagnosticsEngine &Diags,
225                                       DiscriminatorOverrideTy Discriminator,
226                                       bool IsAux = false);
227 };
228 
229 class MicrosoftMangleContext : public MangleContext {
230 public:
231   explicit MicrosoftMangleContext(ASTContext &C, DiagnosticsEngine &D,
232                                   bool IsAux = false)
233       : MangleContext(C, D, MK_Microsoft, IsAux) {}
234 
235   /// Mangle vftable symbols.  Only a subset of the bases along the path
236   /// to the vftable are included in the name.  It's up to the caller to pick
237   /// them correctly.
238   virtual void mangleCXXVFTable(const CXXRecordDecl *Derived,
239                                 ArrayRef<const CXXRecordDecl *> BasePath,
240                                 raw_ostream &Out) = 0;
241 
242   /// Mangle vbtable symbols.  Only a subset of the bases along the path
243   /// to the vbtable are included in the name.  It's up to the caller to pick
244   /// them correctly.
245   virtual void mangleCXXVBTable(const CXXRecordDecl *Derived,
246                                 ArrayRef<const CXXRecordDecl *> BasePath,
247                                 raw_ostream &Out) = 0;
248 
249   virtual void mangleThreadSafeStaticGuardVariable(const VarDecl *VD,
250                                                    unsigned GuardNum,
251                                                    raw_ostream &Out) = 0;
252 
253   virtual void mangleVirtualMemPtrThunk(const CXXMethodDecl *MD,
254                                         const MethodVFTableLocation &ML,
255                                         raw_ostream &Out) = 0;
256 
257   virtual void mangleCXXVirtualDisplacementMap(const CXXRecordDecl *SrcRD,
258                                                const CXXRecordDecl *DstRD,
259                                                raw_ostream &Out) = 0;
260 
261   virtual void mangleCXXThrowInfo(QualType T, bool IsConst, bool IsVolatile,
262                                   bool IsUnaligned, uint32_t NumEntries,
263                                   raw_ostream &Out) = 0;
264 
265   virtual void mangleCXXCatchableTypeArray(QualType T, uint32_t NumEntries,
266                                            raw_ostream &Out) = 0;
267 
268   virtual void mangleCXXCatchableType(QualType T, const CXXConstructorDecl *CD,
269                                       CXXCtorType CT, uint32_t Size,
270                                       uint32_t NVOffset, int32_t VBPtrOffset,
271                                       uint32_t VBIndex, raw_ostream &Out) = 0;
272 
273   virtual void mangleCXXRTTIBaseClassDescriptor(
274       const CXXRecordDecl *Derived, uint32_t NVOffset, int32_t VBPtrOffset,
275       uint32_t VBTableOffset, uint32_t Flags, raw_ostream &Out) = 0;
276 
277   virtual void mangleCXXRTTIBaseClassArray(const CXXRecordDecl *Derived,
278                                            raw_ostream &Out) = 0;
279   virtual void
280   mangleCXXRTTIClassHierarchyDescriptor(const CXXRecordDecl *Derived,
281                                         raw_ostream &Out) = 0;
282 
283   virtual void
284   mangleCXXRTTICompleteObjectLocator(const CXXRecordDecl *Derived,
285                                      ArrayRef<const CXXRecordDecl *> BasePath,
286                                      raw_ostream &Out) = 0;
287 
288   static bool classof(const MangleContext *C) {
289     return C->getKind() == MK_Microsoft;
290   }
291 
292   static MicrosoftMangleContext *
293   create(ASTContext &Context, DiagnosticsEngine &Diags, bool IsAux = false);
294 };
295 
296 class ASTNameGenerator {
297 public:
298   explicit ASTNameGenerator(ASTContext &Ctx);
299   ~ASTNameGenerator();
300 
301   /// Writes name for \p D to \p OS.
302   /// \returns true on failure, false on success.
303   bool writeName(const Decl *D, raw_ostream &OS);
304 
305   /// \returns name for \p D
306   std::string getName(const Decl *D);
307 
308   /// \returns all applicable mangled names.
309   /// For example C++ constructors/destructors can have multiple.
310   std::vector<std::string> getAllManglings(const Decl *D);
311 
312 private:
313   class Implementation;
314   std::unique_ptr<Implementation> Impl;
315 };
316 }
317 
318 #endif
319