llvm-6502/include/llvm/IR/UseListOrder.h
Duncan P. N. Exon Smith f8b862d87c Revert "UseListOrder: Remove move assignment"
This reverts commit r214260.  Turns out move assignment *is* necessary
for MSVC [1].

[1]: http://bb.pgr.jp/builders/ninja-clang-i686-msc17-R/builds/9631

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214264 91177308-0d34-0410-b5e6-96231b3b80d8
2014-07-30 00:25:33 +00:00

122 lines
3.5 KiB
C++

//===- llvm/IR/UseListOrder.h - LLVM Use List Order functions ---*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file has functions to modify the use-list order and to verify that it
// doesn't change after serialization.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_IR_USELISTORDER_H
#define LLVM_IR_USELISTORDER_H
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/SmallVector.h"
#include <vector>
namespace llvm {
class Module;
class Function;
class Value;
/// \brief Structure to hold a use-list shuffle vector.
///
/// Stores most use-lists locally, but large use-lists use an extra heap entry.
/// Costs two fewer pointers than the equivalent \a SmallVector.
class UseListShuffleVector {
unsigned Size;
union {
unsigned *Ptr;
unsigned Array[6];
} Storage;
bool isSmall() const { return Size <= 6; }
unsigned *data() { return isSmall() ? Storage.Array : Storage.Ptr; }
const unsigned *data() const {
return isSmall() ? Storage.Array : Storage.Ptr;
}
void destroy() {
if (!isSmall())
delete[] Storage.Ptr;
}
void moveUnchecked(UseListShuffleVector &X) {
std::memcpy(this, &X, sizeof(UseListShuffleVector));
X.Size = 0;
}
UseListShuffleVector(const UseListShuffleVector &X) LLVM_DELETED_FUNCTION;
UseListShuffleVector &
operator=(const UseListShuffleVector &X) LLVM_DELETED_FUNCTION;
public:
UseListShuffleVector() : Size(0) {}
UseListShuffleVector(UseListShuffleVector &&X) { moveUnchecked(X); }
UseListShuffleVector &operator=(UseListShuffleVector &&X) {
destroy();
moveUnchecked(X);
return *this;
}
explicit UseListShuffleVector(size_t Size) : Size(Size) {
if (!isSmall())
Storage.Ptr = new unsigned[Size];
}
~UseListShuffleVector() { destroy(); }
typedef unsigned *iterator;
typedef const unsigned *const_iterator;
size_t size() const { return Size; }
iterator begin() { return data(); }
iterator end() { return begin() + size(); }
const_iterator begin() const { return data(); }
const_iterator end() const { return begin() + size(); }
unsigned &operator[](size_t I) { return data()[I]; }
unsigned operator[](size_t I) const { return data()[I]; }
};
/// \brief Structure to hold a use-list order.
struct UseListOrder {
const Value *V;
const Function *F;
UseListShuffleVector Shuffle;
UseListOrder(const Value *V, const Function *F, size_t ShuffleSize)
: V(V), F(F), Shuffle(ShuffleSize) {}
UseListOrder() : V(0), F(0) {}
UseListOrder(UseListOrder &&X)
: V(X.V), F(X.F), Shuffle(std::move(X.Shuffle)) {}
UseListOrder &operator=(UseListOrder &&X) {
V = X.V;
F = X.F;
Shuffle = std::move(X.Shuffle);
return *this;
}
private:
UseListOrder(const UseListOrder &X) LLVM_DELETED_FUNCTION;
UseListOrder &operator=(const UseListOrder &X) LLVM_DELETED_FUNCTION;
};
typedef std::vector<UseListOrder> UseListOrderStack;
/// \brief Whether to preserve use-list ordering.
bool shouldPreserveBitcodeUseListOrder();
bool shouldPreserveAssemblyUseListOrder();
/// \brief Shuffle all use-lists in a module.
///
/// Adds \c SeedOffset to the default seed for the random number generator.
void shuffleUseLists(Module &M, unsigned SeedOffset = 0);
} // end namespace llvm
#endif