1//===- llvm/ValueSymbolTable.h - Implement a Value Symtab -------*- 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 implements the name/Value symbol table for LLVM.
10//
11//===----------------------------------------------------------------------===//
12
13#ifndef LLVM_IR_VALUESYMBOLTABLE_H
14#define LLVM_IR_VALUESYMBOLTABLE_H
15
16#include "llvm/ADT/StringMap.h"
17#include "llvm/ADT/StringRef.h"
18#include "llvm/IR/Value.h"
19#include <cstdint>
20
21namespace llvm {
22
23class Argument;
24class BasicBlock;
25class Function;
26class GlobalAlias;
27class GlobalIFunc;
28class GlobalVariable;
29class Instruction;
30template <bool ExtraIteratorBits> struct ilist_iterator_bits;
31template <unsigned InternalLen> class SmallString;
32template <typename ValueSubClass, typename ... Args> class SymbolTableListTraits;
33
34/// This class provides a symbol table of name/value pairs. It is essentially
35/// a std::map<std::string,Value*> but has a controlled interface provided by
36/// LLVM as well as ensuring uniqueness of names.
37///
38class ValueSymbolTable {
39  friend class SymbolTableListTraits<Argument>;
40  friend class SymbolTableListTraits<BasicBlock>;
41  friend class SymbolTableListTraits<Function>;
42  friend class SymbolTableListTraits<GlobalAlias>;
43  friend class SymbolTableListTraits<GlobalIFunc>;
44  friend class SymbolTableListTraits<GlobalVariable>;
45  friend class SymbolTableListTraits<Instruction, ilist_iterator_bits<true>>;
46  friend class Value;
47
48/// @name Types
49/// @{
50public:
51  /// A mapping of names to values.
52  using ValueMap = StringMap<Value*>;
53
54  /// An iterator over a ValueMap.
55  using iterator = ValueMap::iterator;
56
57  /// A const_iterator over a ValueMap.
58  using const_iterator = ValueMap::const_iterator;
59
60/// @}
61/// @name Constructors
62/// @{
63
64  ValueSymbolTable(int MaxNameSize = -1) : vmap(0), MaxNameSize(MaxNameSize) {}
65  ~ValueSymbolTable();
66
67  /// @}
68  /// @name Accessors
69  /// @{
70
71  /// This method finds the value with the given \p Name in the
72  /// the symbol table.
73  /// @returns the value associated with the \p Name
74  /// Lookup a named Value.
75  Value *lookup(StringRef Name) const {
76    if (MaxNameSize > -1 && Name.size() > (unsigned)MaxNameSize)
77      Name = Name.substr(0, std::max(1u, (unsigned)MaxNameSize));
78
79    return vmap.lookup(Name);
80  }
81
82  /// @returns true iff the symbol table is empty
83  /// Determine if the symbol table is empty
84  inline bool empty() const { return vmap.empty(); }
85
86  /// The number of name/type pairs is returned.
87  inline unsigned size() const { return unsigned(vmap.size()); }
88
89  /// This function can be used from the debugger to display the
90  /// content of the symbol table while debugging.
91  /// Print out symbol table on stderr
92  void dump() const;
93
94/// @}
95/// @name Iteration
96/// @{
97
98  /// Get an iterator that from the beginning of the symbol table.
99  inline iterator begin() { return vmap.begin(); }
100
101  /// Get a const_iterator that from the beginning of the symbol table.
102  inline const_iterator begin() const { return vmap.begin(); }
103
104  /// Get an iterator to the end of the symbol table.
105  inline iterator end() { return vmap.end(); }
106
107  /// Get a const_iterator to the end of the symbol table.
108  inline const_iterator end() const { return vmap.end(); }
109
110  /// @}
111  /// @name Mutators
112  /// @{
113private:
114  ValueName *makeUniqueName(Value *V, SmallString<256> &UniqueName);
115
116  /// This method adds the provided value \p N to the symbol table.  The Value
117  /// must have a name which is used to place the value in the symbol table.
118  /// If the inserted name conflicts, this renames the value.
119  /// Add a named value to the symbol table
120  void reinsertValue(Value *V);
121
122  /// createValueName - This method attempts to create a value name and insert
123  /// it into the symbol table with the specified name.  If it conflicts, it
124  /// auto-renames the name and returns that instead.
125  ValueName *createValueName(StringRef Name, Value *V);
126
127  /// This method removes a value from the symbol table.  It leaves the
128  /// ValueName attached to the value, but it is no longer inserted in the
129  /// symtab.
130  void removeValueName(ValueName *V);
131
132  /// @}
133  /// @name Internal Data
134  /// @{
135
136  ValueMap vmap;                    ///< The map that holds the symbol table.
137  int MaxNameSize; ///< The maximum size for each name. If the limit is
138                   ///< exceeded, the name is capped.
139  mutable uint32_t LastUnique = 0;  ///< Counter for tracking unique names
140
141/// @}
142};
143
144} // end namespace llvm
145
146#endif // LLVM_IR_VALUESYMBOLTABLE_H
147