lib/Bitcode/Reader/ValueList.h

   1 //===-- Bitcode/Reader/ValueList.h - Number values --------------*- 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 // This class gives values and types Unique ID's.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #ifndef LLVM_LIB_BITCODE_READER_VALUELIST_H
  15 #define LLVM_LIB_BITCODE_READER_VALUELIST_H
  16
  17 #include "llvm/IR/ValueHandle.h"
  18 #include <cassert>
  19 #include <utility>
  20 #include <vector>
  21
  22 namespace llvm {
  23
  24 class Constant;
  25 class LLVMContext;
  26 class Type;
  27 class Value;
  28
  29 class BitcodeReaderValueList {
  30   std::vector<WeakTrackingVH> ValuePtrs;
  31
  32   /// As we resolve forward-referenced constants, we add information about them
  33   /// to this vector.  This allows us to resolve them in bulk instead of
  34   /// resolving each reference at a time.  See the code in
  35   /// ResolveConstantForwardRefs for more information about this.
  36   ///
  37   /// The key of this vector is the placeholder constant, the value is the slot
  38   /// number that holds the resolved value.
  39   using ResolveConstantsTy = std::vector<std::pair<Constant *, unsigned>>;
  40   ResolveConstantsTy ResolveConstants;
  41   LLVMContext &Context;
  42
  43 public:
  44   BitcodeReaderValueList(LLVMContext &C) : Context(C) {}
  45
  46   ~BitcodeReaderValueList() {
  47     assert(ResolveConstants.empty() && "Constants not resolved?");
  48   }
  49
  50   // vector compatibility methods
  51   unsigned size() const { return ValuePtrs.size(); }
  52   void resize(unsigned N) { ValuePtrs.resize(N); }
  53   void push_back(Value *V) { ValuePtrs.emplace_back(V); }
  54
  55   void clear() {
  56     assert(ResolveConstants.empty() && "Constants not resolved?");
  57     ValuePtrs.clear();
  58   }
  59
  60   Value *operator[](unsigned i) const {
  61     assert(i < ValuePtrs.size());
  62     return ValuePtrs[i];
  63   }
  64
  65   Value *back() const { return ValuePtrs.back(); }
  66   void pop_back() { ValuePtrs.pop_back(); }
  67   bool empty() const { return ValuePtrs.empty(); }
  68
  69   void shrinkTo(unsigned N) {
  70     assert(N <= size() && "Invalid shrinkTo request!");
  71     ValuePtrs.resize(N);
  72   }
  73
  74   Constant *getConstantFwdRef(unsigned Idx, Type *Ty);
  75   Value *getValueFwdRef(unsigned Idx, Type *Ty);
  76
  77   void assignValue(Value *V, unsigned Idx);
  78
  79   /// Once all constants are read, this method bulk resolves any forward
  80   /// references.
  81   void resolveConstantForwardRefs();
  82 };
  83
  84 } // end namespace llvm
  85
  86 #endif // LLVM_LIB_BITCODE_READER_VALUELIST_H