include/llvm/Metadata.h

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