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_IR_METADATA_H
17#define LLVM_IR_METADATA_H
18
19#include "llvm/ADT/ArrayRef.h"
20#include "llvm/ADT/FoldingSet.h"
21#include "llvm/ADT/ilist_node.h"
22#include "llvm/IR/Value.h"
23
24namespace llvm {
25class LLVMContext;
26class Module;
27template<typename ValueSubClass, typename ItemParentClass>
28  class SymbolTableListTraits;
29
30
31//===----------------------------------------------------------------------===//
32/// MDString - a single uniqued string.
33/// These are used to efficiently contain a byte sequence for metadata.
34/// MDString is always unnamed.
35class MDString : public Value {
36  virtual void anchor();
37  MDString(const MDString &) LLVM_DELETED_FUNCTION;
38
39  explicit MDString(LLVMContext &C);
40public:
41  static MDString *get(LLVMContext &Context, StringRef Str);
42  static MDString *get(LLVMContext &Context, const char *Str) {
43    return get(Context, Str ? StringRef(Str) : StringRef());
44  }
45
46  StringRef getString() const { return getName(); }
47
48  unsigned getLength() const { return (unsigned)getName().size(); }
49
50  typedef StringRef::iterator iterator;
51
52  /// begin() - Pointer to the first byte of the string.
53  iterator begin() const { return getName().begin(); }
54
55  /// end() - Pointer to one byte past the end of the string.
56  iterator end() const { return getName().end(); }
57
58  /// Methods for support type inquiry through isa, cast, and dyn_cast:
59  static bool classof(const Value *V) {
60    return V->getValueID() == MDStringVal;
61  }
62};
63
64
65class MDNodeOperand;
66
67//===----------------------------------------------------------------------===//
68/// MDNode - a tuple of other values.
69class MDNode : public Value, public FoldingSetNode {
70  MDNode(const MDNode &) LLVM_DELETED_FUNCTION;
71  void operator=(const MDNode &) LLVM_DELETED_FUNCTION;
72  friend class MDNodeOperand;
73  friend class LLVMContextImpl;
74  friend struct FoldingSetTrait<MDNode>;
75
76  /// Hash - If the MDNode is uniqued cache the hash to speed up lookup.
77  unsigned Hash;
78
79  /// NumOperands - This many 'MDNodeOperand' items are co-allocated onto the
80  /// end of this MDNode.
81  unsigned NumOperands;
82
83  // Subclass data enums.
84  enum {
85    /// FunctionLocalBit - This bit is set if this MDNode is function local.
86    /// This is true when it (potentially transitively) contains a reference to
87    /// something in a function, like an argument, basicblock, or instruction.
88    FunctionLocalBit = 1 << 0,
89
90    /// NotUniquedBit - This is set on MDNodes that are not uniqued because they
91    /// have a null operand.
92    NotUniquedBit    = 1 << 1,
93
94    /// DestroyFlag - This bit is set by destroy() so the destructor can assert
95    /// that the node isn't being destroyed with a plain 'delete'.
96    DestroyFlag      = 1 << 2
97  };
98
99  // FunctionLocal enums.
100  enum FunctionLocalness {
101    FL_Unknown = -1,
102    FL_No = 0,
103    FL_Yes = 1
104  };
105
106  /// replaceOperand - Replace each instance of F from the operand list of this
107  /// node with T.
108  void replaceOperand(MDNodeOperand *Op, Value *NewVal);
109  ~MDNode();
110
111  MDNode(LLVMContext &C, ArrayRef<Value*> Vals, bool isFunctionLocal);
112
113  static MDNode *getMDNode(LLVMContext &C, ArrayRef<Value*> Vals,
114                           FunctionLocalness FL, bool Insert = true);
115public:
116  // Constructors and destructors.
117  static MDNode *get(LLVMContext &Context, ArrayRef<Value*> Vals);
118  // getWhenValsUnresolved - Construct MDNode determining function-localness
119  // from isFunctionLocal argument, not by analyzing Vals.
120  static MDNode *getWhenValsUnresolved(LLVMContext &Context,
121                                       ArrayRef<Value*> Vals,
122                                       bool isFunctionLocal);
123
124  static MDNode *getIfExists(LLVMContext &Context, ArrayRef<Value*> Vals);
125
126  /// getTemporary - Return a temporary MDNode, for use in constructing
127  /// cyclic MDNode structures. A temporary MDNode is not uniqued,
128  /// may be RAUW'd, and must be manually deleted with deleteTemporary.
129  static MDNode *getTemporary(LLVMContext &Context, ArrayRef<Value*> Vals);
130
131  /// deleteTemporary - Deallocate a node created by getTemporary. The
132  /// node must not have any users.
133  static void deleteTemporary(MDNode *N);
134
135  /// replaceOperandWith - Replace a specific operand.
136  void replaceOperandWith(unsigned i, Value *NewVal);
137
138  /// getOperand - Return specified operand.
139  Value *getOperand(unsigned i) const LLVM_READONLY;
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 bool classof(const Value *V) {
161    return V->getValueID() == MDNodeVal;
162  }
163
164  /// Methods for metadata merging.
165  static MDNode *getMostGenericTBAA(MDNode *A, MDNode *B);
166  static MDNode *getMostGenericFPMath(MDNode *A, MDNode *B);
167  static MDNode *getMostGenericRange(MDNode *A, MDNode *B);
168private:
169  // destroy - Delete this node.  Only when there are no uses.
170  void destroy();
171
172  bool isNotUniqued() const {
173    return (getSubclassDataFromValue() & NotUniquedBit) != 0;
174  }
175  void setIsNotUniqued();
176
177  // Shadow Value::setValueSubclassData with a private forwarding method so that
178  // any future subclasses cannot accidentally use it.
179  void setValueSubclassData(unsigned short D) {
180    Value::setValueSubclassData(D);
181  }
182};
183
184//===----------------------------------------------------------------------===//
185/// NamedMDNode - a tuple of MDNodes. Despite its name, a NamedMDNode isn't
186/// itself an MDNode. NamedMDNodes belong to modules, have names, and contain
187/// lists of MDNodes.
188class NamedMDNode : public ilist_node<NamedMDNode> {
189  friend class SymbolTableListTraits<NamedMDNode, Module>;
190  friend struct ilist_traits<NamedMDNode>;
191  friend class LLVMContextImpl;
192  friend class Module;
193  NamedMDNode(const NamedMDNode &) LLVM_DELETED_FUNCTION;
194
195  std::string Name;
196  Module *Parent;
197  void *Operands; // SmallVector<TrackingVH<MDNode>, 4>
198
199  void setParent(Module *M) { Parent = M; }
200
201  explicit NamedMDNode(const Twine &N);
202
203public:
204  /// eraseFromParent - Drop all references and remove the node from parent
205  /// module.
206  void eraseFromParent();
207
208  /// dropAllReferences - Remove all uses and clear node vector.
209  void dropAllReferences();
210
211  /// ~NamedMDNode - Destroy NamedMDNode.
212  ~NamedMDNode();
213
214  /// getParent - Get the module that holds this named metadata collection.
215  inline Module *getParent() { return Parent; }
216  inline const Module *getParent() const { return Parent; }
217
218  /// getOperand - Return specified operand.
219  MDNode *getOperand(unsigned i) const;
220
221  /// getNumOperands - Return the number of NamedMDNode operands.
222  unsigned getNumOperands() const;
223
224  /// addOperand - Add metadata operand.
225  void addOperand(MDNode *M);
226
227  /// getName - Return a constant reference to this named metadata's name.
228  StringRef getName() const;
229
230  /// print - Implement operator<< on NamedMDNode.
231  void print(raw_ostream &ROS, AssemblyAnnotationWriter *AAW = 0) const;
232
233  /// dump() - Allow printing of NamedMDNodes from the debugger.
234  void dump() const;
235};
236
237} // end llvm namespace
238
239#endif
240