clang  10.0.0svn
TypeLocBuilder.h
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1 //===--- TypeLocBuilder.h - Type Source Info collector ----------*- 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 // This file defines TypeLocBuilder, a class for building TypeLocs
10 // bottom-up.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_CLANG_LIB_SEMA_TYPELOCBUILDER_H
15 #define LLVM_CLANG_LIB_SEMA_TYPELOCBUILDER_H
16 
17 #include "clang/AST/ASTContext.h"
18 #include "clang/AST/TypeLoc.h"
19 
20 namespace clang {
21 
23  enum { InlineCapacity = 8 * sizeof(SourceLocation) };
24 
25  /// The underlying location-data buffer. Data grows from the end
26  /// of the buffer backwards.
27  char *Buffer;
28 
29  /// The capacity of the current buffer.
30  size_t Capacity;
31 
32  /// The index of the first occupied byte in the buffer.
33  size_t Index;
34 
35 #ifndef NDEBUG
36  /// The last type pushed on this builder.
37  QualType LastTy;
38 #endif
39 
40  /// The inline buffer.
41  enum { BufferMaxAlignment = alignof(void *) };
42  alignas(BufferMaxAlignment) char InlineBuffer[InlineCapacity];
43  unsigned NumBytesAtAlign4, NumBytesAtAlign8;
44 
45 public:
47  : Buffer(InlineBuffer), Capacity(InlineCapacity), Index(InlineCapacity),
48  NumBytesAtAlign4(0), NumBytesAtAlign8(0) {}
49 
51  if (Buffer != InlineBuffer)
52  delete[] Buffer;
53  }
54 
55  /// Ensures that this buffer has at least as much capacity as described.
56  void reserve(size_t Requested) {
57  if (Requested > Capacity)
58  // For now, match the request exactly.
59  grow(Requested);
60  }
61 
62  /// Pushes a copy of the given TypeLoc onto this builder. The builder
63  /// must be empty for this to work.
64  void pushFullCopy(TypeLoc L);
65 
66  /// Pushes space for a typespec TypeLoc. Invalidates any TypeLocs
67  /// previously retrieved from this builder.
69  size_t LocalSize = TypeSpecTypeLoc::LocalDataSize;
70  unsigned LocalAlign = TypeSpecTypeLoc::LocalDataAlignment;
71  return pushImpl(T, LocalSize, LocalAlign).castAs<TypeSpecTypeLoc>();
72  }
73 
74  /// Resets this builder to the newly-initialized state.
75  void clear() {
76 #ifndef NDEBUG
77  LastTy = QualType();
78 #endif
79  Index = Capacity;
80  NumBytesAtAlign4 = NumBytesAtAlign8 = 0;
81  }
82 
83  /// Tell the TypeLocBuilder that the type it is storing has been
84  /// modified in some safe way that doesn't affect type-location information.
86 #ifndef NDEBUG
87  LastTy = T;
88 #endif
89  }
90 
91  /// Pushes space for a new TypeLoc of the given type. Invalidates
92  /// any TypeLocs previously retrieved from this builder.
93  template <class TyLocType> TyLocType push(QualType T) {
94  TyLocType Loc = TypeLoc(T, nullptr).castAs<TyLocType>();
95  size_t LocalSize = Loc.getLocalDataSize();
96  unsigned LocalAlign = Loc.getLocalDataAlignment();
97  return pushImpl(T, LocalSize, LocalAlign).castAs<TyLocType>();
98  }
99 
100  /// Creates a TypeSourceInfo for the given type.
102 #ifndef NDEBUG
103  assert(T == LastTy && "type doesn't match last type pushed!");
104 #endif
105 
106  size_t FullDataSize = Capacity - Index;
107  TypeSourceInfo *DI = Context.CreateTypeSourceInfo(T, FullDataSize);
108  memcpy(DI->getTypeLoc().getOpaqueData(), &Buffer[Index], FullDataSize);
109  return DI;
110  }
111 
112  /// Copies the type-location information to the given AST context and
113  /// returns a \c TypeLoc referring into the AST context.
115 #ifndef NDEBUG
116  assert(T == LastTy && "type doesn't match last type pushed!");
117 #endif
118 
119  size_t FullDataSize = Capacity - Index;
120  void *Mem = Context.Allocate(FullDataSize);
121  memcpy(Mem, &Buffer[Index], FullDataSize);
122  return TypeLoc(T, Mem);
123  }
124 
125 private:
126 
127  TypeLoc pushImpl(QualType T, size_t LocalSize, unsigned LocalAlignment);
128 
129  /// Grow to the given capacity.
130  void grow(size_t NewCapacity);
131 
132  /// Retrieve a temporary TypeLoc that refers into this \c TypeLocBuilder
133  /// object.
134  ///
135  /// The resulting \c TypeLoc should only be used so long as the
136  /// \c TypeLocBuilder is active and has not had more type information
137  /// pushed into it.
138  TypeLoc getTemporaryTypeLoc(QualType T) {
139 #ifndef NDEBUG
140  assert(LastTy == T && "type doesn't match last type pushed!");
141 #endif
142  return TypeLoc(T, &Buffer[Index]);
143  }
144 };
145 
146 }
147 
148 #endif
Defines the clang::ASTContext interface.
A (possibly-)qualified type.
Definition: Type.h:643
A container of type source information.
Definition: Decl.h:86
A reasonable base class for TypeLocs that correspond to types that are written as a type-specifier...
Definition: TypeLoc.h:509
Base wrapper for a particular "section" of type source info.
Definition: TypeLoc.h:56
Holds long-lived AST nodes (such as types and decls) that can be referred to throughout the semantic ...
Definition: ASTContext.h:160
TypeSourceInfo * getTypeSourceInfo(ASTContext &Context, QualType T)
Creates a TypeSourceInfo for the given type.
TypeSpecTypeLoc pushTypeSpec(QualType T)
Pushes space for a typespec TypeLoc.
TyLocType push(QualType T)
Pushes space for a new TypeLoc of the given type.
void * getOpaqueData() const
Get the pointer where source information is stored.
Definition: TypeLoc.h:139
void TypeWasModifiedSafely(QualType T)
Tell the TypeLocBuilder that the type it is storing has been modified in some safe way that doesn&#39;t a...
Defines the clang::TypeLoc interface and its subclasses.
TypeLoc getTypeLocInContext(ASTContext &Context, QualType T)
Copies the type-location information to the given AST context and returns a TypeLoc referring into th...
void clear()
Resets this builder to the newly-initialized state.
Encodes a location in the source.
TypeSourceInfo * CreateTypeSourceInfo(QualType T, unsigned Size=0) const
Allocate an uninitialized TypeSourceInfo.
void reserve(size_t Requested)
Ensures that this buffer has at least as much capacity as described.
__DEVICE__ void * memcpy(void *__a, const void *__b, size_t __c)
void * Allocate(size_t Size, unsigned Align=8) const
Definition: ASTContext.h:682
Dataflow Directional Tag Classes.
TypeLoc getTypeLoc() const
Return the TypeLoc wrapper for the type source info.
Definition: TypeLoc.h:240
T castAs() const
Convert to the specified TypeLoc type, asserting that this TypeLoc is of the desired type...
Definition: TypeLoc.h:75
void pushFullCopy(TypeLoc L)
Pushes a copy of the given TypeLoc onto this builder.