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  virtual void anchor();
40  MDString(const MDString &);            // DO NOT IMPLEMENT
41
42  explicit MDString(LLVMContext &C);
43public:
44  static MDString *get(LLVMContext &Context, StringRef Str);
45  static MDString *get(LLVMContext &Context, const char *Str) {
46    return get(Context, Str ? StringRef(Str) : StringRef());
47  }
48
49  StringRef getString() const { return getName(); }
50
51  unsigned getLength() const { return (unsigned)getName().size(); }
52
53  typedef StringRef::iterator iterator;
54
55  /// begin() - Pointer to the first byte of the string.
56  iterator begin() const { return getName().begin(); }
57
58  /// end() - Pointer to one byte past the end of the string.
59  iterator end() const { return getName().end(); }
60
61  /// Methods for support type inquiry through isa, cast, and dyn_cast:
62  static inline bool classof(const MDString *) { return true; }
63  static bool classof(const Value *V) {
64    return V->getValueID() == MDStringVal;
65  }
66};
67
68
69class MDNodeOperand;
70
71//===----------------------------------------------------------------------===//
72/// MDNode - a tuple of other values.
73class MDNode : public Value, public FoldingSetNode {
74  MDNode(const MDNode &);                // DO NOT IMPLEMENT
75  void operator=(const MDNode &);        // DO NOT IMPLEMENT
76  friend class MDNodeOperand;
77  friend class LLVMContextImpl;
78  friend struct FoldingSetTrait<MDNode>;
79
80  /// Hash - If the MDNode is uniqued cache the hash to speed up lookup.
81  unsigned Hash;
82
83  /// NumOperands - This many 'MDNodeOperand' items are co-allocated onto the
84  /// end of this MDNode.
85  unsigned NumOperands;
86
87  // Subclass data enums.
88  enum {
89    /// FunctionLocalBit - This bit is set if this MDNode is function local.
90    /// This is true when it (potentially transitively) contains a reference to
91    /// something in a function, like an argument, basicblock, or instruction.
92    FunctionLocalBit = 1 << 0,
93
94    /// NotUniquedBit - This is set on MDNodes that are not uniqued because they
95    /// have a null operand.
96    NotUniquedBit    = 1 << 1,
97
98    /// DestroyFlag - This bit is set by destroy() so the destructor can assert
99    /// that the node isn't being destroyed with a plain 'delete'.
100    DestroyFlag      = 1 << 2
101  };
102
103  // FunctionLocal enums.
104  enum FunctionLocalness {
105    FL_Unknown = -1,
106    FL_No = 0,
107    FL_Yes = 1
108  };
109
110  /// replaceOperand - Replace each instance of F from the operand list of this
111  /// node with T.
112  void replaceOperand(MDNodeOperand *Op, Value *NewVal);
113  ~MDNode();
114
115  MDNode(LLVMContext &C, ArrayRef<Value*> Vals, bool isFunctionLocal);
116
117  static MDNode *getMDNode(LLVMContext &C, ArrayRef<Value*> Vals,
118                           FunctionLocalness FL, bool Insert = true);
119public:
120  // Constructors and destructors.
121  static MDNode *get(LLVMContext &Context, ArrayRef<Value*> Vals);
122  // getWhenValsUnresolved - Construct MDNode determining function-localness
123  // from isFunctionLocal argument, not by analyzing Vals.
124  static MDNode *getWhenValsUnresolved(LLVMContext &Context,
125                                       ArrayRef<Value*> Vals,
126                                       bool isFunctionLocal);
127
128  static MDNode *getIfExists(LLVMContext &Context, ArrayRef<Value*> Vals);
129
130  /// getTemporary - Return a temporary MDNode, for use in constructing
131  /// cyclic MDNode structures. A temporary MDNode is not uniqued,
132  /// may be RAUW'd, and must be manually deleted with deleteTemporary.
133  static MDNode *getTemporary(LLVMContext &Context, ArrayRef<Value*> Vals);
134
135  /// deleteTemporary - Deallocate a node created by getTemporary. The
136  /// node must not have any users.
137  static void deleteTemporary(MDNode *N);
138
139  /// replaceOperandWith - Replace a specific operand.
140  void replaceOperandWith(unsigned i, Value *NewVal);
141
142  /// getOperand - Return specified operand.
143  Value *getOperand(unsigned i) const;
144
145  /// getNumOperands - Return number of MDNode operands.
146  unsigned getNumOperands() const { return NumOperands; }
147
148  /// isFunctionLocal - Return whether MDNode is local to a function.
149  bool isFunctionLocal() const {
150    return (getSubclassDataFromValue() & FunctionLocalBit) != 0;
151  }
152
153  // getFunction - If this metadata is function-local and recursively has a
154  // function-local operand, return the first such operand's parent function.
155  // Otherwise, return null. getFunction() should not be used for performance-
156  // critical code because it recursively visits all the MDNode's operands.
157  const Function *getFunction() const;
158
159  /// Profile - calculate a unique identifier for this MDNode to collapse
160  /// duplicates
161  void Profile(FoldingSetNodeID &ID) const;
162
163  /// Methods for support type inquiry through isa, cast, and dyn_cast:
164  static inline bool classof(const MDNode *) { return true; }
165  static bool classof(const Value *V) {
166    return V->getValueID() == MDNodeVal;
167  }
168
169  /// Methods for metadata merging.
170  static MDNode *getMostGenericTBAA(MDNode *A, MDNode *B);
171  static MDNode *getMostGenericFPMath(MDNode *A, MDNode *B);
172  static MDNode *getMostGenericRange(MDNode *A, MDNode *B);
173private:
174  // destroy - Delete this node.  Only when there are no uses.
175  void destroy();
176
177  bool isNotUniqued() const {
178    return (getSubclassDataFromValue() & NotUniquedBit) != 0;
179  }
180  void setIsNotUniqued();
181
182  // Shadow Value::setValueSubclassData with a private forwarding method so that
183  // any future subclasses cannot accidentally use it.
184  void setValueSubclassData(unsigned short D) {
185    Value::setValueSubclassData(D);
186  }
187};
188
189//===----------------------------------------------------------------------===//
190/// NamedMDNode - a tuple of MDNodes. Despite its name, a NamedMDNode isn't
191/// itself an MDNode. NamedMDNodes belong to modules, have names, and contain
192/// lists of MDNodes.
193class NamedMDNode : public ilist_node<NamedMDNode> {
194  friend class SymbolTableListTraits<NamedMDNode, Module>;
195  friend struct ilist_traits<NamedMDNode>;
196  friend class LLVMContextImpl;
197  friend class Module;
198  NamedMDNode(const NamedMDNode &);      // DO NOT IMPLEMENT
199
200  std::string Name;
201  Module *Parent;
202  void *Operands; // SmallVector<TrackingVH<MDNode>, 4>
203
204  void setParent(Module *M) { Parent = M; }
205
206  explicit NamedMDNode(const Twine &N);
207
208public:
209  /// eraseFromParent - Drop all references and remove the node from parent
210  /// module.
211  void eraseFromParent();
212
213  /// dropAllReferences - Remove all uses and clear node vector.
214  void dropAllReferences();
215
216  /// ~NamedMDNode - Destroy NamedMDNode.
217  ~NamedMDNode();
218
219  /// getParent - Get the module that holds this named metadata collection.
220  inline Module *getParent() { return Parent; }
221  inline const Module *getParent() const { return Parent; }
222
223  /// getOperand - Return specified operand.
224  MDNode *getOperand(unsigned i) const;
225
226  /// getNumOperands - Return the number of NamedMDNode operands.
227  unsigned getNumOperands() const;
228
229  /// addOperand - Add metadata operand.
230  void addOperand(MDNode *M);
231
232  /// getName - Return a constant reference to this named metadata's name.
233  StringRef getName() const;
234
235  /// print - Implement operator<< on NamedMDNode.
236  void print(raw_ostream &ROS, AssemblyAnnotationWriter *AAW = 0) const;
237
238  /// dump() - Allow printing of NamedMDNodes from the debugger.
239  void dump() const;
240};
241
242} // end llvm namespace
243
244#endif
245