clang  12.0.0git
AbstractBasicReader.h
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1 //==--- AbstractBasiceReader.h - Abstract basic value deserialization -----===//
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 #ifndef CLANG_AST_ABSTRACTBASICREADER_H
10 #define CLANG_AST_ABSTRACTBASICREADER_H
11 
12 #include "clang/AST/DeclTemplate.h"
13 
14 namespace clang {
15 namespace serialization {
16 
17 template <class T>
18 inline T makeNullableFromOptional(const Optional<T> &value) {
19  return (value ? *value : T());
20 }
21 
22 template <class T>
24  return (value ? *value : nullptr);
25 }
26 
27 // PropertyReader is a class concept that requires the following method:
28 // BasicReader find(llvm::StringRef propertyName);
29 // where BasicReader is some class conforming to the BasicReader concept.
30 // An abstract AST-node reader is created with a PropertyReader and
31 // performs a sequence of calls like so:
32 // propertyReader.find(propertyName).read##TypeName()
33 // to read the properties of the node it is deserializing.
34 
35 // BasicReader is a class concept that requires methods like:
36 // ValueType read##TypeName();
37 // where TypeName is the name of a PropertyType node from PropertiesBase.td
38 // and ValueType is the corresponding C++ type name. The read method may
39 // require one or more buffer arguments.
40 //
41 // In addition to the concrete type names, BasicReader is expected to
42 // implement these methods:
43 //
44 // template <class EnumType>
45 // void writeEnum(T value);
46 //
47 // Reads an enum value from the current property. EnumType will always
48 // be an enum type. Only necessary if the BasicReader doesn't provide
49 // type-specific readers for all the enum types.
50 //
51 // template <class ValueType>
52 // Optional<ValueType> writeOptional();
53 //
54 // Reads an optional value from the current property.
55 //
56 // template <class ValueType>
57 // ArrayRef<ValueType> readArray(llvm::SmallVectorImpl<ValueType> &buffer);
58 //
59 // Reads an array of values from the current property.
60 //
61 // PropertyReader readObject();
62 //
63 // Reads an object from the current property; the returned property
64 // reader will be subjected to a sequence of property reads and then
65 // discarded before any other properties are reader from the "outer"
66 // property reader (which need not be the same type). The sub-reader
67 // will be used as if with the following code:
68 //
69 // {
70 // auto &&widget = W.find("widget").readObject();
71 // auto kind = widget.find("kind").readWidgetKind();
72 // auto declaration = widget.find("declaration").readDeclRef();
73 // return Widget(kind, declaration);
74 // }
75 
76 // ReadDispatcher does type-based forwarding to one of the read methods
77 // on the BasicReader passed in:
78 //
79 // template <class ValueType>
80 // struct ReadDispatcher {
81 // template <class BasicReader, class... BufferTypes>
82 // static ValueType read(BasicReader &R, BufferTypes &&...);
83 // };
84 
85 // BasicReaderBase provides convenience implementations of the read methods
86 // for EnumPropertyType and SubclassPropertyType types that just defer to
87 // the "underlying" implementations (for UInt32 and the base class,
88 // respectively).
89 //
90 // template <class Impl>
91 // class BasicReaderBase {
92 // protected:
93 // BasicReaderBase(ASTContext &ctx);
94 // Impl &asImpl();
95 // public:
96 // ASTContext &getASTContext();
97 // ...
98 // };
99 
100 // The actual classes are auto-generated; see ClangASTPropertiesEmitter.cpp.
101 #include "clang/AST/AbstractBasicReader.inc"
102 
103 /// DataStreamBasicReader provides convenience implementations for many
104 /// BasicReader methods based on the assumption that the
105 /// ultimate reader implementation is based on a variable-length stream
106 /// of unstructured data (like Clang's module files). It is designed
107 /// to pair with DataStreamBasicWriter.
108 ///
109 /// This class can also act as a PropertyReader, implementing find("...")
110 /// by simply forwarding to itself.
111 ///
112 /// Unimplemented methods:
113 /// readBool
114 /// readUInt32
115 /// readUInt64
116 /// readIdentifier
117 /// readSelector
118 /// readSourceLocation
119 /// readQualType
120 /// readStmtRef
121 /// readDeclRef
122 template <class Impl>
123 class DataStreamBasicReader : public BasicReaderBase<Impl> {
124 protected:
125  using BasicReaderBase<Impl>::asImpl;
126  DataStreamBasicReader(ASTContext &ctx) : BasicReaderBase<Impl>(ctx) {}
127 
128 public:
129  using BasicReaderBase<Impl>::getASTContext;
130 
131  /// Implement property-find by ignoring it. We rely on properties being
132  /// serialized and deserialized in a reliable order instead.
133  Impl &find(const char *propertyName) {
134  return asImpl();
135  }
136 
137  template <class T>
138  T readEnum() {
139  return T(asImpl().readUInt32());
140  }
141 
142  // Implement object reading by forwarding to this, collapsing the
143  // structure into a single data stream.
144  Impl &readObject() { return asImpl(); }
145 
146  template <class T>
148  assert(buffer.empty());
149 
150  uint32_t size = asImpl().readUInt32();
151  buffer.reserve(size);
152 
153  for (uint32_t i = 0; i != size; ++i) {
154  buffer.push_back(ReadDispatcher<T>::read(asImpl()));
155  }
156  return buffer;
157  }
158 
159  template <class T, class... Args>
160  llvm::Optional<T> readOptional(Args &&...args) {
161  return UnpackOptionalValue<T>::unpack(
162  ReadDispatcher<T>::read(asImpl(), std::forward<Args>(args)...));
163  }
164 
166  bool isUnsigned = asImpl().readBool();
167  llvm::APInt value = asImpl().readAPInt();
168  return llvm::APSInt(std::move(value), isUnsigned);
169  }
170 
172  unsigned bitWidth = asImpl().readUInt32();
173  unsigned numWords = llvm::APInt::getNumWords(bitWidth);
175  for (uint32_t i = 0; i != numWords; ++i)
176  data.push_back(asImpl().readUInt64());
177  return llvm::APInt(bitWidth, numWords, &data[0]);
178  }
179 
181  static_assert(sizeof(Qualifiers().getAsOpaqueValue()) <= sizeof(uint32_t),
182  "update this if the value size changes");
183  uint32_t value = asImpl().readUInt32();
184  return Qualifiers::fromOpaqueValue(value);
185  }
186 
190  esi.Type = ExceptionSpecificationType(asImpl().readUInt32());
191  if (esi.Type == EST_Dynamic) {
192  esi.Exceptions = asImpl().template readArray<QualType>(buffer);
193  } else if (isComputedNoexcept(esi.Type)) {
194  esi.NoexceptExpr = asImpl().readExprRef();
195  } else if (esi.Type == EST_Uninstantiated) {
196  esi.SourceDecl = asImpl().readFunctionDeclRef();
197  esi.SourceTemplate = asImpl().readFunctionDeclRef();
198  } else if (esi.Type == EST_Unevaluated) {
199  esi.SourceDecl = asImpl().readFunctionDeclRef();
200  }
201  return esi;
202  }
203 
205  static_assert(sizeof(FunctionProtoType::ExtParameterInfo().getOpaqueValue())
206  <= sizeof(uint32_t),
207  "opaque value doesn't fit into uint32_t");
208  uint32_t value = asImpl().readUInt32();
210  }
211 
213  auto &ctx = getASTContext();
214 
215  // We build this up iteratively.
216  NestedNameSpecifier *cur = nullptr;
217 
218  uint32_t depth = asImpl().readUInt32();
219  for (uint32_t i = 0; i != depth; ++i) {
220  auto kind = asImpl().readNestedNameSpecifierKind();
221  switch (kind) {
223  cur = NestedNameSpecifier::Create(ctx, cur,
224  asImpl().readIdentifier());
225  continue;
226 
228  cur = NestedNameSpecifier::Create(ctx, cur,
229  asImpl().readNamespaceDeclRef());
230  continue;
231 
233  cur = NestedNameSpecifier::Create(ctx, cur,
234  asImpl().readNamespaceAliasDeclRef());
235  continue;
236 
239  cur = NestedNameSpecifier::Create(ctx, cur,
241  asImpl().readQualType().getTypePtr());
242  continue;
243 
246  continue;
247 
250  asImpl().readCXXRecordDeclRef());
251  continue;
252  }
253  llvm_unreachable("bad nested name specifier kind");
254  }
255 
256  return cur;
257  }
258 };
259 
260 } // end namespace serialization
261 } // end namespace clang
262 
263 #endif
llvm::Optional< T > readOptional(Args &&...args)
Microsoft&#39;s &#39;__super&#39; specifier, stored as a CXXRecordDecl* of the class it appeared in...
FunctionProtoType::ExceptionSpecInfo readExceptionSpecInfo(llvm::SmallVectorImpl< QualType > &buffer)
Defines the C++ template declaration subclasses.
T makeNullableFromOptional(const Optional< T > &value)
An identifier, stored as an IdentifierInfo*.
static Qualifiers fromOpaqueValue(unsigned opaque)
Definition: Type.h:250
static NestedNameSpecifier * Create(const ASTContext &Context, NestedNameSpecifier *Prefix, IdentifierInfo *II)
Builds a specifier combining a prefix and an identifier.
A namespace, stored as a NamespaceDecl*.
The collection of all-type qualifiers we support.
Definition: Type.h:144
Holds long-lived AST nodes (such as types and decls) that can be referred to throughout the semantic ...
Definition: ASTContext.h:174
llvm::ArrayRef< T > readArray(llvm::SmallVectorImpl< T > &buffer)
Impl & find(const char *propertyName)
Implement property-find by ignoring it.
FunctionDecl * SourceDecl
The function whose exception specification this is, for EST_Unevaluated and EST_Uninstantiated.
Definition: Type.h:3955
DataStreamBasicReader provides convenience implementations for many BasicReader methods based on the ...
static ExtParameterInfo getFromOpaqueValue(unsigned char data)
Definition: Type.h:3623
static NestedNameSpecifier * SuperSpecifier(const ASTContext &Context, CXXRecordDecl *RD)
Returns the nested name specifier representing the __super scope for the given CXXRecordDecl.
A namespace alias, stored as a NamespaceAliasDecl*.
bool isComputedNoexcept(ExceptionSpecificationType ESpecType)
ExceptionSpecificationType Type
The kind of exception specification this is.
Definition: Type.h:3945
llvm::APSInt APSInt
Represents a C++ nested name specifier, such as "\::std::vector<int>::".
llvm::APInt APInt
Definition: Integral.h:27
T * makePointerFromOptional(Optional< T *> value)
Dataflow Directional Tag Classes.
not evaluated yet, for special member function
FunctionProtoType::ExtParameterInfo readExtParameterInfo()
Interesting information about a specific parameter that can&#39;t simply be reflected in parameter&#39;s type...
Definition: Type.h:3573
A type that was preceded by the &#39;template&#39; keyword, stored as a Type*.
FunctionDecl * SourceTemplate
The function template whose exception specification this is instantiated from, for EST_Uninstantiated...
Definition: Type.h:3959
ExceptionSpecificationType
The various types of exception specifications that exist in C++11.
Holds information about the various types of exception specification.
Definition: Type.h:3943
ArrayRef< QualType > Exceptions
Explicitly-specified list of exception types.
Definition: Type.h:3948
Expr * NoexceptExpr
Noexcept expression, if this is a computed noexcept specification.
Definition: Type.h:3951
unsigned kind
All of the diagnostics that can be emitted by the frontend.
Definition: DiagnosticIDs.h:60
The global specifier &#39;::&#39;. There is no stored value.
static NestedNameSpecifier * GlobalSpecifier(const ASTContext &Context)
Returns the nested name specifier representing the global scope.