1//===-- llvm/Metadata.h - Metadata definitions ------------------*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10/// @file
11/// This file contains the declarations for metadata subclasses.
12/// They represent the different flavors of metadata that live in LLVM.
13//
14//===----------------------------------------------------------------------===//
15
16#ifndef LLVM_METADATA_H
17#define LLVM_METADATA_H
18
19#include "llvm/Value.h"
20#include "llvm/ADT/ArrayRef.h"
21#include "llvm/ADT/FoldingSet.h"
22#include "llvm/ADT/ilist_node.h"
23
24namespace llvm {
25class Constant;
26class Instruction;
27class LLVMContext;
28class Module;
29template <typename T> class SmallVectorImpl;
30template<typename ValueSubClass, typename ItemParentClass>
31  class SymbolTableListTraits;
32
33
34//===----------------------------------------------------------------------===//
35/// MDString - a single uniqued string.
36/// These are used to efficiently contain a byte sequence for metadata.
37/// MDString is always unnamed.
38class MDString : public Value {
39  MDString(const MDString &);            // DO NOT IMPLEMENT
40
41  StringRef Str;
42  explicit MDString(LLVMContext &C, StringRef S);
43
44public:
45  static MDString *get(LLVMContext &Context, StringRef Str);
46  static MDString *get(LLVMContext &Context, const char *Str) {
47    return get(Context, Str ? StringRef(Str) : StringRef());
48  }
49
50  StringRef getString() const { return Str; }
51
52  unsigned getLength() const { return (unsigned)Str.size(); }
53
54  typedef StringRef::iterator iterator;
55
56  /// begin() - Pointer to the first byte of the string.
57  ///
58  iterator begin() const { return Str.begin(); }
59
60  /// end() - Pointer to one byte past the end of the string.
61  ///
62  iterator end() const { return Str.end(); }
63
64  /// Methods for support type inquiry through isa, cast, and dyn_cast:
65  static inline bool classof(const MDString *) { return true; }
66  static bool classof(const Value *V) {
67    return V->getValueID() == MDStringVal;
68  }
69};
70
71
72class MDNodeOperand;
73
74//===----------------------------------------------------------------------===//
75/// MDNode - a tuple of other values.
76class MDNode : public Value, public FoldingSetNode {
77  MDNode(const MDNode &);                // DO NOT IMPLEMENT
78  void operator=(const MDNode &);        // DO NOT IMPLEMENT
79  friend class MDNodeOperand;
80  friend class LLVMContextImpl;
81
82  /// NumOperands - This many 'MDNodeOperand' items are co-allocated onto the
83  /// end of this MDNode.
84  unsigned NumOperands;
85
86  // Subclass data enums.
87  enum {
88    /// FunctionLocalBit - This bit is set if this MDNode is function local.
89    /// This is true when it (potentially transitively) contains a reference to
90    /// something in a function, like an argument, basicblock, or instruction.
91    FunctionLocalBit = 1 << 0,
92
93    /// NotUniquedBit - This is set on MDNodes that are not uniqued because they
94    /// have a null operand.
95    NotUniquedBit    = 1 << 1,
96
97    /// DestroyFlag - This bit is set by destroy() so the destructor can assert
98    /// that the node isn't being destroyed with a plain 'delete'.
99    DestroyFlag      = 1 << 2
100  };
101
102  // FunctionLocal enums.
103  enum FunctionLocalness {
104    FL_Unknown = -1,
105    FL_No = 0,
106    FL_Yes = 1
107  };
108
109  /// replaceOperand - Replace each instance of F from the operand list of this
110  /// node with T.
111  void replaceOperand(MDNodeOperand *Op, Value *NewVal);
112  ~MDNode();
113
114  MDNode(LLVMContext &C, ArrayRef<Value*> Vals, bool isFunctionLocal);
115
116  static MDNode *getMDNode(LLVMContext &C, ArrayRef<Value*> Vals,
117                           FunctionLocalness FL, bool Insert = true);
118public:
119  // Constructors and destructors.
120  static MDNode *get(LLVMContext &Context, ArrayRef<Value*> Vals);
121  // getWhenValsUnresolved - Construct MDNode determining function-localness
122  // from isFunctionLocal argument, not by analyzing Vals.
123  static MDNode *getWhenValsUnresolved(LLVMContext &Context,
124                                       ArrayRef<Value*> Vals,
125                                       bool isFunctionLocal);
126
127  static MDNode *getIfExists(LLVMContext &Context, ArrayRef<Value*> Vals);
128
129  /// getTemporary - Return a temporary MDNode, for use in constructing
130  /// cyclic MDNode structures. A temporary MDNode is not uniqued,
131  /// may be RAUW'd, and must be manually deleted with deleteTemporary.
132  static MDNode *getTemporary(LLVMContext &Context, ArrayRef<Value*> Vals);
133
134  /// deleteTemporary - Deallocate a node created by getTemporary. The
135  /// node must not have any users.
136  static void deleteTemporary(MDNode *N);
137
138  /// getOperand - Return specified operand.
139  Value *getOperand(unsigned i) const;
140
141  /// getNumOperands - Return number of MDNode operands.
142  unsigned getNumOperands() const { return NumOperands; }
143
144  /// isFunctionLocal - Return whether MDNode is local to a function.
145  bool isFunctionLocal() const {
146    return (getSubclassDataFromValue() & FunctionLocalBit) != 0;
147  }
148
149  // getFunction - If this metadata is function-local and recursively has a
150  // function-local operand, return the first such operand's parent function.
151  // Otherwise, return null. getFunction() should not be used for performance-
152  // critical code because it recursively visits all the MDNode's operands.
153  const Function *getFunction() const;
154
155  /// Profile - calculate a unique identifier for this MDNode to collapse
156  /// duplicates
157  void Profile(FoldingSetNodeID &ID) const;
158
159  /// Methods for support type inquiry through isa, cast, and dyn_cast:
160  static inline bool classof(const MDNode *) { return true; }
161  static bool classof(const Value *V) {
162    return V->getValueID() == MDNodeVal;
163  }
164private:
165  // destroy - Delete this node.  Only when there are no uses.
166  void destroy();
167
168  bool isNotUniqued() const {
169    return (getSubclassDataFromValue() & NotUniquedBit) != 0;
170  }
171  void setIsNotUniqued();
172
173  // Shadow Value::setValueSubclassData with a private forwarding method so that
174  // any future subclasses cannot accidentally use it.
175  void setValueSubclassData(unsigned short D) {
176    Value::setValueSubclassData(D);
177  }
178};
179
180//===----------------------------------------------------------------------===//
181/// NamedMDNode - a tuple of MDNodes. Despite its name, a NamedMDNode isn't
182/// itself an MDNode. NamedMDNodes belong to modules, have names, and contain
183/// lists of MDNodes.
184class NamedMDNode : public ilist_node<NamedMDNode> {
185  friend class SymbolTableListTraits<NamedMDNode, Module>;
186  friend struct ilist_traits<NamedMDNode>;
187  friend class LLVMContextImpl;
188  friend class Module;
189  NamedMDNode(const NamedMDNode &);      // DO NOT IMPLEMENT
190
191  std::string Name;
192  Module *Parent;
193  void *Operands; // SmallVector<TrackingVH<MDNode>, 4>
194
195  void setParent(Module *M) { Parent = M; }
196
197  explicit NamedMDNode(const Twine &N);
198
199public:
200  /// eraseFromParent - Drop all references and remove the node from parent
201  /// module.
202  void eraseFromParent();
203
204  /// dropAllReferences - Remove all uses and clear node vector.
205  void dropAllReferences();
206
207  /// ~NamedMDNode - Destroy NamedMDNode.
208  ~NamedMDNode();
209
210  /// getParent - Get the module that holds this named metadata collection.
211  inline Module *getParent() { return Parent; }
212  inline const Module *getParent() const { return Parent; }
213
214  /// getOperand - Return specified operand.
215  MDNode *getOperand(unsigned i) const;
216
217  /// getNumOperands - Return the number of NamedMDNode operands.
218  unsigned getNumOperands() const;
219
220  /// addOperand - Add metadata operand.
221  void addOperand(MDNode *M);
222
223  /// getName - Return a constant reference to this named metadata's name.
224  StringRef getName() const;
225
226  /// print - Implement operator<< on NamedMDNode.
227  void print(raw_ostream &ROS, AssemblyAnnotationWriter *AAW = 0) const;
228};
229
230} // end llvm namespace
231
232#endif
233