lib/VMCore/LLVMContext.cpp

   1 //===-- LLVMContext.cpp - Implement LLVMContext -----------------------===//
   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 LLVMContext, as a wrapper around the opaque
  11 //  class LLVMContextImpl.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "llvm/LLVMContext.h"
  16 #include "llvm/Metadata.h"
  17 #include "llvm/Constants.h"
  18 #include "llvm/Instruction.h"
  19 #include "llvm/Support/ManagedStatic.h"
  20 #include "llvm/Support/ValueHandle.h"
  21 #include "LLVMContextImpl.h"
  22 #include <set>
  23
  24 using namespace llvm;
  25
  26 static ManagedStatic<LLVMContext> GlobalContext;
  27
  28 LLVMContext& llvm::getGlobalContext() {
  29   return *GlobalContext;
  30 }
  31
  32 LLVMContext::LLVMContext() : pImpl(new LLVMContextImpl(*this)) { }
  33 LLVMContext::~LLVMContext() { delete pImpl; }
  34
  35 GetElementPtrConstantExpr::GetElementPtrConstantExpr
  36   (Constant *C,
  37    const std::vector<Constant*> &IdxList,
  38    const Type *DestTy)
  39     : ConstantExpr(DestTy, Instruction::GetElementPtr,
  40                    OperandTraits<GetElementPtrConstantExpr>::op_end(this)
  41                    - (IdxList.size()+1),
  42                    IdxList.size()+1) {
  43   OperandList[0] = C;
  44   for (unsigned i = 0, E = IdxList.size(); i != E; ++i)
  45     OperandList[i+1] = IdxList[i];
  46 }
  47
  48 bool LLVMContext::RemoveDeadMetadata() {
  49   std::vector<WeakVH> DeadMDNodes;
  50   bool Changed = false;
  51   while (1) {
  52
  53     for (FoldingSet<MDNode>::iterator
  54            I = pImpl->MDNodeSet.begin(),
  55            E = pImpl->MDNodeSet.end(); I != E; ++I) {
  56       MDNode *N = &(*I);
  57       if (N->use_empty())
  58         DeadMDNodes.push_back(WeakVH(N));
  59     }
  60
  61     if (DeadMDNodes.empty())
  62       return Changed;
  63
  64     while (!DeadMDNodes.empty()) {
  65       Value *V = DeadMDNodes.back(); DeadMDNodes.pop_back();
  66       if (const MDNode *N = dyn_cast_or_null<MDNode>(V))
  67         if (N->use_empty())
  68           delete N;
  69     }
  70   }
  71   return Changed;
  72 }