llvm-project/llvm/lib/Bitcode/Reader/ValueList.h

111 lines
3.3 KiB
C++

//===-- Bitcode/Reader/ValueList.h - Number values --------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This class gives values and types Unique ID's.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIB_BITCODE_READER_VALUELIST_H
#define LLVM_LIB_BITCODE_READER_VALUELIST_H
#include "llvm/IR/ValueHandle.h"
#include <cassert>
#include <utility>
#include <vector>
namespace llvm {
class Constant;
class LLVMContext;
class Type;
class Value;
class BitcodeReaderValueList {
std::vector<WeakTrackingVH> ValuePtrs;
/// Struct containing fully-specified copies of the type of each
/// value. When pointers are opaque, this will be contain non-opaque
/// variants so that restructuring instructions can determine their
/// type correctly even if being loaded from old bitcode where some
/// types are implicit.
std::vector<Type *> FullTypes;
/// As we resolve forward-referenced constants, we add information about them
/// to this vector. This allows us to resolve them in bulk instead of
/// resolving each reference at a time. See the code in
/// ResolveConstantForwardRefs for more information about this.
///
/// The key of this vector is the placeholder constant, the value is the slot
/// number that holds the resolved value.
using ResolveConstantsTy = std::vector<std::pair<Constant *, unsigned>>;
ResolveConstantsTy ResolveConstants;
LLVMContext &Context;
/// Maximum number of valid references. Forward references exceeding the
/// maximum must be invalid.
unsigned RefsUpperBound;
public:
BitcodeReaderValueList(LLVMContext &C, size_t RefsUpperBound)
: Context(C),
RefsUpperBound(std::min((size_t)std::numeric_limits<unsigned>::max(),
RefsUpperBound)) {}
~BitcodeReaderValueList() {
assert(ResolveConstants.empty() && "Constants not resolved?");
}
// vector compatibility methods
unsigned size() const { return ValuePtrs.size(); }
void resize(unsigned N) {
ValuePtrs.resize(N);
FullTypes.resize(N);
}
void push_back(Value *V, Type *Ty) {
ValuePtrs.emplace_back(V);
FullTypes.emplace_back(Ty);
}
void clear() {
assert(ResolveConstants.empty() && "Constants not resolved?");
ValuePtrs.clear();
FullTypes.clear();
}
Value *operator[](unsigned i) const {
assert(i < ValuePtrs.size());
return ValuePtrs[i];
}
Value *back() const { return ValuePtrs.back(); }
void pop_back() {
ValuePtrs.pop_back();
FullTypes.pop_back();
}
bool empty() const { return ValuePtrs.empty(); }
void shrinkTo(unsigned N) {
assert(N <= size() && "Invalid shrinkTo request!");
ValuePtrs.resize(N);
FullTypes.resize(N);
}
Constant *getConstantFwdRef(unsigned Idx, Type *Ty);
Value *getValueFwdRef(unsigned Idx, Type *Ty, Type **FullTy = nullptr);
void assignValue(Value *V, unsigned Idx, Type *FullTy);
/// Once all constants are read, this method bulk resolves any forward
/// references.
void resolveConstantForwardRefs();
};
} // end namespace llvm
#endif // LLVM_LIB_BITCODE_READER_VALUELIST_H