lib/VMCore/Metadata.cpp

   1 //===-- Metadata.cpp - Implement Metadata classes -------------------------===//
   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 // This file implements the Metadata classes.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "LLVMContextImpl.h"
  15 #include "llvm/Metadata.h"
  16 #include "llvm/LLVMContext.h"
  17 #include "llvm/Module.h"
  18 #include "SymbolTableListTraitsImpl.h"
  19 using namespace llvm;
  20
  21 //===----------------------------------------------------------------------===//
  22 //MetadataBase implementation
  23 //
  24
  25 /// resizeOperands - Metadata keeps track of other metadata uses using
  26 /// OperandList. Resize this list to hold anticipated number of metadata
  27 /// operands.
  28 void MetadataBase::resizeOperands(unsigned NumOps) {
  29   unsigned e = getNumOperands();
  30   if (NumOps == 0) {
  31     NumOps = e*2;
  32     if (NumOps < 2) NumOps = 2;
  33   } else if (NumOps > NumOperands) {
  34     // No resize needed.
  35     if (ReservedSpace >= NumOps) return;
  36   } else if (NumOps == NumOperands) {
  37     if (ReservedSpace == NumOps) return;
  38   } else {
  39     return;
  40   }
  41
  42   ReservedSpace = NumOps;
  43   Use *OldOps = OperandList;
  44   Use *NewOps = allocHungoffUses(NumOps);
  45   std::copy(OldOps, OldOps + e, NewOps);
  46   OperandList = NewOps;
  47   if (OldOps) Use::zap(OldOps, OldOps + e, true);
  48 }
  49 //===----------------------------------------------------------------------===//
  50 //MDString implementation
  51 //
  52 MDString *MDString::get(LLVMContext &Context, const StringRef &Str) {
  53   LLVMContextImpl *pImpl = Context.pImpl;
  54   sys::SmartScopedWriter<true> Writer(pImpl->ConstantsLock);
  55   StringMapEntry<MDString *> &Entry =
  56     pImpl->MDStringCache.GetOrCreateValue(Str);
  57   MDString *&S = Entry.getValue();
  58   if (!S) S = new MDString(Entry.getKeyData(),
  59                            Entry.getKeyLength());
  60
  61   return S;
  62 }
  63
  64 //===----------------------------------------------------------------------===//
  65 //MDNode implementation
  66 //
  67 MDNode::MDNode(Value*const* Vals, unsigned NumVals)
  68   : MetadataBase(Type::MetadataTy, Value::MDNodeVal) {
  69   NumOperands = 0;
  70   resizeOperands(NumVals);
  71   for (unsigned i = 0; i != NumVals; ++i) {
  72     // Only record metadata uses.
  73     if (MetadataBase *MB = dyn_cast_or_null<MetadataBase>(Vals[i]))
  74       OperandList[NumOperands++] = MB;
  75     Node.push_back(WeakVH(Vals[i]));
  76   }
  77 }
  78
  79 void MDNode::Profile(FoldingSetNodeID &ID) const {
  80   for (const_elem_iterator I = elem_begin(), E = elem_end(); I != E; ++I)
  81     ID.AddPointer(*I);
  82 }
  83
  84 MDNode *MDNode::get(LLVMContext &Context, Value*const* Vals, unsigned NumVals) {
  85   LLVMContextImpl *pImpl = Context.pImpl;
  86   FoldingSetNodeID ID;
  87   for (unsigned i = 0; i != NumVals; ++i)
  88     ID.AddPointer(Vals[i]);
  89
  90   pImpl->ConstantsLock.reader_acquire();
  91   void *InsertPoint;
  92   MDNode *N = pImpl->MDNodeSet.FindNodeOrInsertPos(ID, InsertPoint);
  93   pImpl->ConstantsLock.reader_release();
  94
  95   if (!N) {
  96     sys::SmartScopedWriter<true> Writer(pImpl->ConstantsLock);
  97     N = pImpl->MDNodeSet.FindNodeOrInsertPos(ID, InsertPoint);
  98     if (!N) {
  99       // InsertPoint will have been set by the FindNodeOrInsertPos call.
 100       N = new MDNode(Vals, NumVals);
 101       pImpl->MDNodeSet.InsertNode(N, InsertPoint);
 102     }
 103   }
 104
 105   return N;
 106 }
 107
 108 /// dropAllReferences - Remove all uses and clear node vector.
 109 void MDNode::dropAllReferences() {
 110   User::dropAllReferences();
 111   Node.clear();
 112 }
 113
 114 MDNode::~MDNode() {
 115   dropAllReferences();
 116 }
 117 //===----------------------------------------------------------------------===//
 118 //NamedMDNode implementation
 119 //
 120 NamedMDNode::NamedMDNode(const Twine &N, MetadataBase*const* MDs,
 121                          unsigned NumMDs, Module *ParentModule)
 122   : MetadataBase(Type::MetadataTy, Value::NamedMDNodeVal), Parent(0) {
 123   setName(N);
 124   NumOperands = 0;
 125   resizeOperands(NumMDs);
 126
 127   for (unsigned i = 0; i != NumMDs; ++i) {
 128     if (MDs[i])
 129       OperandList[NumOperands++] = MDs[i];
 130     Node.push_back(WeakMetadataVH(MDs[i]));
 131   }
 132   if (ParentModule)
 133     ParentModule->getNamedMDList().push_back(this);
 134 }
 135
 136 /// eraseFromParent - Drop all references and remove the node from parent
 137 /// module.
 138 void NamedMDNode::eraseFromParent() {
 139   getParent()->getNamedMDList().erase(this);
 140 }
 141
 142 /// dropAllReferences - Remove all uses and clear node vector.
 143 void NamedMDNode::dropAllReferences() {
 144   User::dropAllReferences();
 145   Node.clear();
 146 }
 147
 148 NamedMDNode::~NamedMDNode() {
 149   dropAllReferences();
 150 }