1 //===-- llvm/SymbolTable.h - Implement a type plane'd symtab ----*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and re-written by Reid
6 // Spencer. It is distributed under the University of Illinois Open Source
7 // License. See LICENSE.TXT for details.
9 //===----------------------------------------------------------------------===//
11 // This file implements the main symbol table for LLVM.
13 //===----------------------------------------------------------------------===//
15 #ifndef LLVM_SYMBOL_TABLE_H
16 #define LLVM_SYMBOL_TABLE_H
18 #include "llvm/Value.h"
19 #include "llvm/Support/DataTypes.h"
24 /// This class provides a symbol table of name/value pairs that is broken
25 /// up by type. For each Type* there is a "plane" of name/value pairs in
26 /// the symbol table. Identical types may have overlapping symbol names as
27 /// long as they are distinct. The SymbolTable also tracks, separately, a
28 /// map of name/type pairs. This allows types to be named. Types are treated
29 /// distinctly from Values.
31 /// The SymbolTable provides several utility functions for answering common
32 /// questions about its contents as well as an iterator interface for
33 /// directly iterating over the contents. To reduce confusion, the terms
34 /// "type", "value", and "plane" are used consistently. For example,
35 /// There is a TypeMap typedef that is the mapping of names to Types.
36 /// Similarly there is a ValueMap typedef that is the mapping of
37 /// names to Values. Finally, there is a PlaneMap typedef that is the
38 /// mapping of types to planes of ValueMap. This is the basic structure
39 /// of the symbol table. When you call type_begin() you're asking
40 /// for an iterator at the start of the TypeMap. When you call
41 /// plane_begin(), you're asking for an iterator at the start of
42 /// the PlaneMap. Finally, when you call value_begin(), you're asking
43 /// for an iterator at the start of a ValueMap for a specific type
45 class SymbolTable : public AbstractTypeUser {
51 /// @brief A mapping of names to types.
52 typedef std::map<const std::string, const Type*> TypeMap;
54 /// @brief An iterator over the TypeMap.
55 typedef TypeMap::iterator type_iterator;
57 /// @brief A const_iterator over the TypeMap.
58 typedef TypeMap::const_iterator type_const_iterator;
60 /// @brief A mapping of names to values.
61 typedef std::map<const std::string, Value *> ValueMap;
63 /// @brief An iterator over a ValueMap.
64 typedef ValueMap::iterator value_iterator;
66 /// @brief A const_iterator over a ValueMap.
67 typedef ValueMap::const_iterator value_const_iterator;
69 /// @brief A mapping of types to names to values (type planes).
70 typedef std::map<const Type *, ValueMap> PlaneMap;
72 /// @brief An iterator over the type planes.
73 typedef PlaneMap::iterator plane_iterator;
75 /// @brief A const_iterator over the type planes
76 typedef PlaneMap::const_iterator plane_const_iterator;
79 /// @name Constructors
83 SymbolTable() : LastUnique(0) {}
91 /// This method finds the value with the given \p name in the
92 /// type plane \p Ty and returns it. This method will not find any
93 /// Types, only Values. Use lookupType to find Types by name.
94 /// @returns null on failure, otherwise the Value associated with
95 /// the \p name in type plane \p Ty.
96 /// @brief Lookup a named, typed value.
97 Value *lookup(const Type *Ty, const std::string &name) const;
99 /// This method finds the type with the given \p name in the
100 /// type map and returns it.
101 /// @returns null if the name is not found, otherwise the Type
102 /// associated with the \p name.
103 /// @brief Lookup a type by name.
104 Type* lookupType(const std::string& name) const;
106 /// @returns true iff the type map and the type plane are both not
108 /// @brief Determine if the symbol table is empty
109 inline bool isEmpty() const { return pmap.empty() && tmap.empty(); }
111 /// @brief The number of name/type pairs is returned.
112 inline unsigned num_types() const { return unsigned(tmap.size()); }
114 /// Given a base name, return a string that is either equal to it or
115 /// derived from it that does not already occur in the symbol table
116 /// for the specified type.
117 /// @brief Get a name unique to this symbol table
118 std::string getUniqueName(const Type *Ty,
119 const std::string &BaseName) const;
121 /// This function can be used from the debugger to display the
122 /// content of the symbol table while debugging.
123 /// @brief Print out symbol table on stderr
131 /// Get an iterator that starts at the beginning of the type planes.
132 /// The iterator will iterate over the Type/ValueMap pairs in the
134 inline plane_iterator plane_begin() { return pmap.begin(); }
136 /// Get a const_iterator that starts at the beginning of the type
137 /// planes. The iterator will iterate over the Type/ValueMap pairs
138 /// in the type planes.
139 inline plane_const_iterator plane_begin() const { return pmap.begin(); }
141 /// Get an iterator at the end of the type planes. This serves as
142 /// the marker for end of iteration over the type planes.
143 inline plane_iterator plane_end() { return pmap.end(); }
145 /// Get a const_iterator at the end of the type planes. This serves as
146 /// the marker for end of iteration over the type planes.
147 inline plane_const_iterator plane_end() const { return pmap.end(); }
149 /// Get an iterator that starts at the beginning of a type plane.
150 /// The iterator will iterate over the name/value pairs in the type plane.
151 /// @note The type plane must already exist before using this.
152 inline value_iterator value_begin(const Type *Typ) {
153 assert(Typ && "Can't get value iterator with null type!");
154 return pmap.find(Typ)->second.begin();
157 /// Get a const_iterator that starts at the beginning of a type plane.
158 /// The iterator will iterate over the name/value pairs in the type plane.
159 /// @note The type plane must already exist before using this.
160 inline value_const_iterator value_begin(const Type *Typ) const {
161 assert(Typ && "Can't get value iterator with null type!");
162 return pmap.find(Typ)->second.begin();
165 /// Get an iterator to the end of a type plane. This serves as the marker
166 /// for end of iteration of the type plane.
167 /// @note The type plane must already exist before using this.
168 inline value_iterator value_end(const Type *Typ) {
169 assert(Typ && "Can't get value iterator with null type!");
170 return pmap.find(Typ)->second.end();
173 /// Get a const_iterator to the end of a type plane. This serves as the
174 /// marker for end of iteration of the type plane.
175 /// @note The type plane must already exist before using this.
176 inline value_const_iterator value_end(const Type *Typ) const {
177 assert(Typ && "Can't get value iterator with null type!");
178 return pmap.find(Typ)->second.end();
181 /// Get an iterator to the start of the name/Type map.
182 inline type_iterator type_begin() { return tmap.begin(); }
184 /// @brief Get a const_iterator to the start of the name/Type map.
185 inline type_const_iterator type_begin() const { return tmap.begin(); }
187 /// Get an iterator to the end of the name/Type map. This serves as the
188 /// marker for end of iteration of the types.
189 inline type_iterator type_end() { return tmap.end(); }
191 /// Get a const-iterator to the end of the name/Type map. This serves
192 /// as the marker for end of iteration of the types.
193 inline type_const_iterator type_end() const { return tmap.end(); }
195 /// This method returns a plane_const_iterator for iteration over
196 /// the type planes starting at a specific plane, given by \p Ty.
197 /// @brief Find a type plane.
198 inline plane_const_iterator find(const Type* Typ) const {
199 assert(Typ && "Can't find type plane with null type!");
200 return pmap.find(Typ);
203 /// This method returns a plane_iterator for iteration over the
204 /// type planes starting at a specific plane, given by \p Ty.
205 /// @brief Find a type plane.
206 inline plane_iterator find(const Type* Typ) {
207 assert(Typ && "Can't find type plane with null type!");
208 return pmap.find(Typ);
217 /// This method will strip the symbol table of its names leaving the type and
219 /// @brief Strip the symbol table.
222 /// Inserts a type into the symbol table with the specified name. There can be
223 /// a many-to-one mapping between names and types. This method allows a type
224 /// with an existing entry in the symbol table to get a new name.
225 /// @brief Insert a type under a new name.
226 void insert(const std::string &Name, const Type *Typ);
228 /// Remove a type at the specified position in the symbol table.
229 /// @returns the removed Type.
230 Type* remove(type_iterator TI);
233 /// @name Mutators used by Value::setName and other LLVM internals.
237 /// This method adds the provided value \p N to the symbol table. The Value
238 /// must have both a name and a type which are extracted and used to place the
239 /// value in the correct type plane under the value's name.
240 /// @brief Add a named value to the symbol table
241 inline void insert(Value *Val) {
242 assert(Val && "Can't insert null type into symbol table!");
243 assert(Val->hasName() && "Value must be named to go into symbol table!");
244 insertEntry(Val->getName(), Val->getType(), Val);
247 /// This method removes a named value from the symbol table. The type and name
248 /// of the Value are extracted from \p N and used to lookup the Value in the
249 /// correct type plane. If the Value is not in the symbol table, this method
250 /// silently ignores the request.
251 /// @brief Remove a named value from the symbol table.
252 void remove(Value* Val);
254 /// changeName - Given a value with a non-empty name, remove its existing
255 /// entry from the symbol table and insert a new one for Name. This is
256 /// equivalent to doing "remove(V), V->Name = Name, insert(V)", but is faster,
257 /// and will not temporarily remove the symbol table plane if V is the last
258 /// value in the symtab with that name (which could invalidate iterators to
260 void changeName(Value *V, const std::string &Name);
263 /// @name Internal Methods
266 /// @brief Insert a value into the symbol table with the specified name.
267 void insertEntry(const std::string &Name, const Type *Ty, Value *V);
269 /// This function is called when one of the types in the type plane
271 virtual void refineAbstractType(const DerivedType *OldTy, const Type *NewTy);
273 /// This function markes a type as being concrete (defined).
274 virtual void typeBecameConcrete(const DerivedType *AbsTy);
277 /// @name Internal Data
281 /// This is the main content of the symbol table. It provides
282 /// separate type planes for named values. That is, each named
283 /// value is organized into a separate dictionary based on
284 /// Type. This means that the same name can be used for different
285 /// types without conflict.
286 /// @brief The mapping of types to names to values.
289 /// This is the type plane. It is separated from the pmap
290 /// because the elements of the map are name/Type pairs not
291 /// name/Value pairs and Type is not a Value.
294 /// This value is used to retain the last unique value used
295 /// by getUniqueName to generate unique names.
296 mutable uint32_t LastUnique;
302 } // End llvm namespace