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//===-- AllocaManager.h ---------------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This pass declares the AllocaManager class.
//
//===----------------------------------------------------------------------===//
#ifndef JSBACKEND_ALLOCAMANAGER_H
#define JSBACKEND_ALLOCAMANAGER_H
#include "llvm/ADT/BitVector.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/SetVector.h"
namespace llvm {
class AllocaInst;
class BasicBlock;
class CallInst;
class DataLayout;
class Function;
/// Compute frame layout for allocas.
class AllocaManager {
const DataLayout *DL;
const Function *LifetimeStart;
const Function *LifetimeEnd;
const Function *F;
// Per-block lifetime information.
struct BlockLifetimeInfo {
BitVector Start;
BitVector End;
BitVector LiveIn;
BitVector LiveOut;
};
typedef DenseMap<const BasicBlock *, BlockLifetimeInfo> LivenessMap;
LivenessMap BlockLiveness;
// Worklist for inter-block liveness analysis.
typedef SmallSetVector<const BasicBlock *, 8> InterBlockWorklistVec;
InterBlockWorklistVec InterBlockWorklist;
// Map allocas to their index in AllocasByIndex.
typedef DenseMap<const AllocaInst *, size_t> AllocaMap;
AllocaMap Allocas;
// Information about an alloca. Note that the size and alignment may vary
// from what's in the actual AllocaInst when an alloca is also representing
// another with perhaps greater size and/or alignment needs.
//
// When an alloca is represented by another, its AllocaInfo is marked as
// "forwarded", at which point it no longer holds a size and alignment, but
// the index of the representative AllocaInfo.
class AllocaInfo {
const AllocaInst *Inst;
uint64_t Size;
unsigned Alignment;
public:
AllocaInfo(const AllocaInst *I, uint64_t S, unsigned A)
: Inst(I), Size(S), Alignment(A) {
assert(I != NULL);
assert(A != 0);
assert(!isForwarded());
}
bool isForwarded() const { return Alignment == 0; }
size_t getForwardedID() const {
assert(isForwarded());
return static_cast<size_t>(Size);
}
void forward(size_t i) {
assert(!isForwarded());
Alignment = 0;
Size = i;
assert(isForwarded());
assert(getForwardedID() == i);
}
const AllocaInst *getInst() const { return Inst; }
uint64_t getSize() const { assert(!isForwarded()); return Size; }
unsigned getAlignment() const { assert(!isForwarded()); return Alignment; }
void mergeSize(uint64_t S) {
assert(!isForwarded());
Size = std::max(Size, S);
assert(!isForwarded());
}
void mergeAlignment(unsigned A) {
assert(A != 0);
assert(!isForwarded());
Alignment = std::max(Alignment, A);
assert(!isForwarded());
}
};
typedef SmallVector<AllocaInfo, 32> AllocaVec;
AllocaVec AllocasByIndex;
// For each alloca, which allocas can it safely represent? Allocas are
// identified by AllocasByIndex index.
// TODO: Vector-of-vectors isn't the fastest data structure possible here.
typedef SmallVector<BitVector, 32> AllocaCompatibilityVec;
AllocaCompatibilityVec AllocaCompatibility;
// This is for allocas that will eventually be sorted.
SmallVector<AllocaInfo, 32> SortedAllocas;
// Static allocation results.
struct StaticAllocation {
const AllocaInst *Representative;
uint64_t Offset;
StaticAllocation() {}
StaticAllocation(const AllocaInst *A, uint64_t O)
: Representative(A), Offset(O) {}
};
typedef DenseMap<const AllocaInst *, StaticAllocation> StaticAllocaMap;
StaticAllocaMap StaticAllocas;
uint64_t FrameSize;
uint64_t getSize(const AllocaInst *AI);
unsigned getAlignment(const AllocaInst *AI);
AllocaInfo getInfo(const AllocaInst *AI);
const AllocaInst *getAllocaFromIntrinsic(const CallInst *CI);
static int AllocaSort(const void *l, const void *r);
void collectMarkedAllocas();
void collectBlocks();
void computeInterBlockLiveness();
void computeIntraBlockLiveness();
void computeRepresentatives();
void computeFrameOffsets();
public:
AllocaManager();
/// Analyze the given function and prepare for getRepresentative queries.
void analyze(const Function &Func, const DataLayout &Layout,
bool PerformColoring);
/// Reset all stored state.
void clear();
/// Return the representative alloca for the given alloca. When allocas are
/// merged, one is chosen as the representative to stand for the rest.
/// References to the alloca should take the form of references to the
/// representative.
const AllocaInst *getRepresentative(const AllocaInst *AI) const;
/// Set *offset to the frame offset for the given alloca. Return true if the
/// given alloca is representative, meaning that it needs an explicit
/// definition in the function entry. Return false if some other alloca
/// represents this one.
bool getFrameOffset(const AllocaInst *AI, uint64_t *offset) const;
/// Return the total frame size for all static allocas and associated padding.
uint64_t getFrameSize() const { return FrameSize; }
};
} // namespace llvm
#endif
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