427 lines
14 KiB
C++
427 lines
14 KiB
C++
//===-- Support/FoldingSet.cpp - Uniquing Hash Set --------------*- C++ -*-===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// This file implements a hash set that can be used to remove duplication of
|
|
// nodes in a graph. This code was originally created by Chris Lattner for use
|
|
// with SelectionDAGCSEMap, but was isolated to provide use across the llvm code
|
|
// set.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include "llvm/ADT/FoldingSet.h"
|
|
#include "llvm/Support/Allocator.h"
|
|
#include "llvm/Support/ErrorHandling.h"
|
|
#include "llvm/Support/MathExtras.h"
|
|
#include "llvm/Support/Host.h"
|
|
#include <cassert>
|
|
#include <cstring>
|
|
using namespace llvm;
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// FoldingSetNodeIDRef Implementation
|
|
|
|
/// ComputeHash - Compute a strong hash value for this FoldingSetNodeIDRef,
|
|
/// used to lookup the node in the FoldingSetImpl.
|
|
unsigned FoldingSetNodeIDRef::ComputeHash() const {
|
|
// This is adapted from SuperFastHash by Paul Hsieh.
|
|
unsigned Hash = static_cast<unsigned>(Size);
|
|
for (const unsigned *BP = Data, *E = BP+Size; BP != E; ++BP) {
|
|
unsigned Data = *BP;
|
|
Hash += Data & 0xFFFF;
|
|
unsigned Tmp = ((Data >> 16) << 11) ^ Hash;
|
|
Hash = (Hash << 16) ^ Tmp;
|
|
Hash += Hash >> 11;
|
|
}
|
|
|
|
// Force "avalanching" of final 127 bits.
|
|
Hash ^= Hash << 3;
|
|
Hash += Hash >> 5;
|
|
Hash ^= Hash << 4;
|
|
Hash += Hash >> 17;
|
|
Hash ^= Hash << 25;
|
|
Hash += Hash >> 6;
|
|
return Hash;
|
|
}
|
|
|
|
bool FoldingSetNodeIDRef::operator==(FoldingSetNodeIDRef RHS) const {
|
|
if (Size != RHS.Size) return false;
|
|
return memcmp(Data, RHS.Data, Size*sizeof(*Data)) == 0;
|
|
}
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// FoldingSetNodeID Implementation
|
|
|
|
/// Add* - Add various data types to Bit data.
|
|
///
|
|
void FoldingSetNodeID::AddPointer(const void *Ptr) {
|
|
// Note: this adds pointers to the hash using sizes and endianness that
|
|
// depend on the host. It doesn't matter however, because hashing on
|
|
// pointer values in inherently unstable. Nothing should depend on the
|
|
// ordering of nodes in the folding set.
|
|
intptr_t PtrI = (intptr_t)Ptr;
|
|
Bits.push_back(unsigned(PtrI));
|
|
if (sizeof(intptr_t) > sizeof(unsigned))
|
|
Bits.push_back(unsigned(uint64_t(PtrI) >> 32));
|
|
}
|
|
void FoldingSetNodeID::AddInteger(signed I) {
|
|
Bits.push_back(I);
|
|
}
|
|
void FoldingSetNodeID::AddInteger(unsigned I) {
|
|
Bits.push_back(I);
|
|
}
|
|
void FoldingSetNodeID::AddInteger(long I) {
|
|
AddInteger((unsigned long)I);
|
|
}
|
|
void FoldingSetNodeID::AddInteger(unsigned long I) {
|
|
if (sizeof(long) == sizeof(int))
|
|
AddInteger(unsigned(I));
|
|
else if (sizeof(long) == sizeof(long long)) {
|
|
AddInteger((unsigned long long)I);
|
|
} else {
|
|
llvm_unreachable("unexpected sizeof(long)");
|
|
}
|
|
}
|
|
void FoldingSetNodeID::AddInteger(long long I) {
|
|
AddInteger((unsigned long long)I);
|
|
}
|
|
void FoldingSetNodeID::AddInteger(unsigned long long I) {
|
|
AddInteger(unsigned(I));
|
|
if ((uint64_t)(int)I != I)
|
|
Bits.push_back(unsigned(I >> 32));
|
|
}
|
|
|
|
void FoldingSetNodeID::AddString(StringRef String) {
|
|
unsigned Size = String.size();
|
|
Bits.push_back(Size);
|
|
if (!Size) return;
|
|
|
|
unsigned Units = Size / 4;
|
|
unsigned Pos = 0;
|
|
const unsigned *Base = (const unsigned*) String.data();
|
|
|
|
// If the string is aligned do a bulk transfer.
|
|
if (!((intptr_t)Base & 3)) {
|
|
Bits.append(Base, Base + Units);
|
|
Pos = (Units + 1) * 4;
|
|
} else {
|
|
// Otherwise do it the hard way.
|
|
// To be compatible with above bulk transfer, we need to take endianness
|
|
// into account.
|
|
if (sys::isBigEndianHost()) {
|
|
for (Pos += 4; Pos <= Size; Pos += 4) {
|
|
unsigned V = ((unsigned char)String[Pos - 4] << 24) |
|
|
((unsigned char)String[Pos - 3] << 16) |
|
|
((unsigned char)String[Pos - 2] << 8) |
|
|
(unsigned char)String[Pos - 1];
|
|
Bits.push_back(V);
|
|
}
|
|
} else {
|
|
assert(sys::isLittleEndianHost() && "Unexpected host endianness");
|
|
for (Pos += 4; Pos <= Size; Pos += 4) {
|
|
unsigned V = ((unsigned char)String[Pos - 1] << 24) |
|
|
((unsigned char)String[Pos - 2] << 16) |
|
|
((unsigned char)String[Pos - 3] << 8) |
|
|
(unsigned char)String[Pos - 4];
|
|
Bits.push_back(V);
|
|
}
|
|
}
|
|
}
|
|
|
|
// With the leftover bits.
|
|
unsigned V = 0;
|
|
// Pos will have overshot size by 4 - #bytes left over.
|
|
// No need to take endianness into account here - this is always executed.
|
|
switch (Pos - Size) {
|
|
case 1: V = (V << 8) | (unsigned char)String[Size - 3]; // Fall thru.
|
|
case 2: V = (V << 8) | (unsigned char)String[Size - 2]; // Fall thru.
|
|
case 3: V = (V << 8) | (unsigned char)String[Size - 1]; break;
|
|
default: return; // Nothing left.
|
|
}
|
|
|
|
Bits.push_back(V);
|
|
}
|
|
|
|
// AddNodeID - Adds the Bit data of another ID to *this.
|
|
void FoldingSetNodeID::AddNodeID(const FoldingSetNodeID &ID) {
|
|
Bits.append(ID.Bits.begin(), ID.Bits.end());
|
|
}
|
|
|
|
/// ComputeHash - Compute a strong hash value for this FoldingSetNodeID, used to
|
|
/// lookup the node in the FoldingSetImpl.
|
|
unsigned FoldingSetNodeID::ComputeHash() const {
|
|
return FoldingSetNodeIDRef(Bits.data(), Bits.size()).ComputeHash();
|
|
}
|
|
|
|
/// operator== - Used to compare two nodes to each other.
|
|
///
|
|
bool FoldingSetNodeID::operator==(const FoldingSetNodeID &RHS)const{
|
|
return *this == FoldingSetNodeIDRef(RHS.Bits.data(), RHS.Bits.size());
|
|
}
|
|
|
|
/// operator== - Used to compare two nodes to each other.
|
|
///
|
|
bool FoldingSetNodeID::operator==(FoldingSetNodeIDRef RHS) const {
|
|
return FoldingSetNodeIDRef(Bits.data(), Bits.size()) == RHS;
|
|
}
|
|
|
|
/// Intern - Copy this node's data to a memory region allocated from the
|
|
/// given allocator and return a FoldingSetNodeIDRef describing the
|
|
/// interned data.
|
|
FoldingSetNodeIDRef
|
|
FoldingSetNodeID::Intern(BumpPtrAllocator &Allocator) const {
|
|
unsigned *New = Allocator.Allocate<unsigned>(Bits.size());
|
|
std::uninitialized_copy(Bits.begin(), Bits.end(), New);
|
|
return FoldingSetNodeIDRef(New, Bits.size());
|
|
}
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
/// Helper functions for FoldingSetImpl.
|
|
|
|
/// GetNextPtr - In order to save space, each bucket is a
|
|
/// singly-linked-list. In order to make deletion more efficient, we make
|
|
/// the list circular, so we can delete a node without computing its hash.
|
|
/// The problem with this is that the start of the hash buckets are not
|
|
/// Nodes. If NextInBucketPtr is a bucket pointer, this method returns null:
|
|
/// use GetBucketPtr when this happens.
|
|
static FoldingSetImpl::Node *GetNextPtr(void *NextInBucketPtr) {
|
|
// The low bit is set if this is the pointer back to the bucket.
|
|
if (reinterpret_cast<intptr_t>(NextInBucketPtr) & 1)
|
|
return 0;
|
|
|
|
return static_cast<FoldingSetImpl::Node*>(NextInBucketPtr);
|
|
}
|
|
|
|
|
|
/// testing.
|
|
static void **GetBucketPtr(void *NextInBucketPtr) {
|
|
intptr_t Ptr = reinterpret_cast<intptr_t>(NextInBucketPtr);
|
|
assert((Ptr & 1) && "Not a bucket pointer");
|
|
return reinterpret_cast<void**>(Ptr & ~intptr_t(1));
|
|
}
|
|
|
|
/// GetBucketFor - Hash the specified node ID and return the hash bucket for
|
|
/// the specified ID.
|
|
static void **GetBucketFor(unsigned Hash, void **Buckets, unsigned NumBuckets) {
|
|
// NumBuckets is always a power of 2.
|
|
unsigned BucketNum = Hash & (NumBuckets-1);
|
|
return Buckets + BucketNum;
|
|
}
|
|
|
|
/// AllocateBuckets - Allocated initialized bucket memory.
|
|
static void **AllocateBuckets(unsigned NumBuckets) {
|
|
void **Buckets = static_cast<void**>(calloc(NumBuckets+1, sizeof(void*)));
|
|
// Set the very last bucket to be a non-null "pointer".
|
|
Buckets[NumBuckets] = reinterpret_cast<void*>(-1);
|
|
return Buckets;
|
|
}
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// FoldingSetImpl Implementation
|
|
|
|
FoldingSetImpl::FoldingSetImpl(unsigned Log2InitSize) {
|
|
assert(5 < Log2InitSize && Log2InitSize < 32 &&
|
|
"Initial hash table size out of range");
|
|
NumBuckets = 1 << Log2InitSize;
|
|
Buckets = AllocateBuckets(NumBuckets);
|
|
NumNodes = 0;
|
|
}
|
|
FoldingSetImpl::~FoldingSetImpl() {
|
|
free(Buckets);
|
|
}
|
|
void FoldingSetImpl::clear() {
|
|
// Set all but the last bucket to null pointers.
|
|
memset(Buckets, 0, NumBuckets*sizeof(void*));
|
|
|
|
// Set the very last bucket to be a non-null "pointer".
|
|
Buckets[NumBuckets] = reinterpret_cast<void*>(-1);
|
|
|
|
// Reset the node count to zero.
|
|
NumNodes = 0;
|
|
}
|
|
|
|
/// GrowHashTable - Double the size of the hash table and rehash everything.
|
|
///
|
|
void FoldingSetImpl::GrowHashTable() {
|
|
void **OldBuckets = Buckets;
|
|
unsigned OldNumBuckets = NumBuckets;
|
|
NumBuckets <<= 1;
|
|
|
|
// Clear out new buckets.
|
|
Buckets = AllocateBuckets(NumBuckets);
|
|
NumNodes = 0;
|
|
|
|
// Walk the old buckets, rehashing nodes into their new place.
|
|
FoldingSetNodeID TempID;
|
|
for (unsigned i = 0; i != OldNumBuckets; ++i) {
|
|
void *Probe = OldBuckets[i];
|
|
if (!Probe) continue;
|
|
while (Node *NodeInBucket = GetNextPtr(Probe)) {
|
|
// Figure out the next link, remove NodeInBucket from the old link.
|
|
Probe = NodeInBucket->getNextInBucket();
|
|
NodeInBucket->SetNextInBucket(0);
|
|
|
|
// Insert the node into the new bucket, after recomputing the hash.
|
|
InsertNode(NodeInBucket,
|
|
GetBucketFor(ComputeNodeHash(NodeInBucket, TempID),
|
|
Buckets, NumBuckets));
|
|
TempID.clear();
|
|
}
|
|
}
|
|
|
|
free(OldBuckets);
|
|
}
|
|
|
|
/// FindNodeOrInsertPos - Look up the node specified by ID. If it exists,
|
|
/// return it. If not, return the insertion token that will make insertion
|
|
/// faster.
|
|
FoldingSetImpl::Node
|
|
*FoldingSetImpl::FindNodeOrInsertPos(const FoldingSetNodeID &ID,
|
|
void *&InsertPos) {
|
|
|
|
void **Bucket = GetBucketFor(ID.ComputeHash(), Buckets, NumBuckets);
|
|
void *Probe = *Bucket;
|
|
|
|
InsertPos = 0;
|
|
|
|
FoldingSetNodeID TempID;
|
|
while (Node *NodeInBucket = GetNextPtr(Probe)) {
|
|
if (NodeEquals(NodeInBucket, ID, TempID))
|
|
return NodeInBucket;
|
|
TempID.clear();
|
|
|
|
Probe = NodeInBucket->getNextInBucket();
|
|
}
|
|
|
|
// Didn't find the node, return null with the bucket as the InsertPos.
|
|
InsertPos = Bucket;
|
|
return 0;
|
|
}
|
|
|
|
/// InsertNode - Insert the specified node into the folding set, knowing that it
|
|
/// is not already in the map. InsertPos must be obtained from
|
|
/// FindNodeOrInsertPos.
|
|
void FoldingSetImpl::InsertNode(Node *N, void *InsertPos) {
|
|
assert(N->getNextInBucket() == 0);
|
|
// Do we need to grow the hashtable?
|
|
if (NumNodes+1 > NumBuckets*2) {
|
|
GrowHashTable();
|
|
FoldingSetNodeID TempID;
|
|
InsertPos = GetBucketFor(ComputeNodeHash(N, TempID), Buckets, NumBuckets);
|
|
}
|
|
|
|
++NumNodes;
|
|
|
|
/// The insert position is actually a bucket pointer.
|
|
void **Bucket = static_cast<void**>(InsertPos);
|
|
|
|
void *Next = *Bucket;
|
|
|
|
// If this is the first insertion into this bucket, its next pointer will be
|
|
// null. Pretend as if it pointed to itself, setting the low bit to indicate
|
|
// that it is a pointer to the bucket.
|
|
if (Next == 0)
|
|
Next = reinterpret_cast<void*>(reinterpret_cast<intptr_t>(Bucket)|1);
|
|
|
|
// Set the node's next pointer, and make the bucket point to the node.
|
|
N->SetNextInBucket(Next);
|
|
*Bucket = N;
|
|
}
|
|
|
|
/// RemoveNode - Remove a node from the folding set, returning true if one was
|
|
/// removed or false if the node was not in the folding set.
|
|
bool FoldingSetImpl::RemoveNode(Node *N) {
|
|
// Because each bucket is a circular list, we don't need to compute N's hash
|
|
// to remove it.
|
|
void *Ptr = N->getNextInBucket();
|
|
if (Ptr == 0) return false; // Not in folding set.
|
|
|
|
--NumNodes;
|
|
N->SetNextInBucket(0);
|
|
|
|
// Remember what N originally pointed to, either a bucket or another node.
|
|
void *NodeNextPtr = Ptr;
|
|
|
|
// Chase around the list until we find the node (or bucket) which points to N.
|
|
while (true) {
|
|
if (Node *NodeInBucket = GetNextPtr(Ptr)) {
|
|
// Advance pointer.
|
|
Ptr = NodeInBucket->getNextInBucket();
|
|
|
|
// We found a node that points to N, change it to point to N's next node,
|
|
// removing N from the list.
|
|
if (Ptr == N) {
|
|
NodeInBucket->SetNextInBucket(NodeNextPtr);
|
|
return true;
|
|
}
|
|
} else {
|
|
void **Bucket = GetBucketPtr(Ptr);
|
|
Ptr = *Bucket;
|
|
|
|
// If we found that the bucket points to N, update the bucket to point to
|
|
// whatever is next.
|
|
if (Ptr == N) {
|
|
*Bucket = NodeNextPtr;
|
|
return true;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/// GetOrInsertNode - If there is an existing simple Node exactly
|
|
/// equal to the specified node, return it. Otherwise, insert 'N' and it
|
|
/// instead.
|
|
FoldingSetImpl::Node *FoldingSetImpl::GetOrInsertNode(FoldingSetImpl::Node *N) {
|
|
FoldingSetNodeID ID;
|
|
GetNodeProfile(N, ID);
|
|
void *IP;
|
|
if (Node *E = FindNodeOrInsertPos(ID, IP))
|
|
return E;
|
|
InsertNode(N, IP);
|
|
return N;
|
|
}
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// FoldingSetIteratorImpl Implementation
|
|
|
|
FoldingSetIteratorImpl::FoldingSetIteratorImpl(void **Bucket) {
|
|
// Skip to the first non-null non-self-cycle bucket.
|
|
while (*Bucket != reinterpret_cast<void*>(-1) &&
|
|
(*Bucket == 0 || GetNextPtr(*Bucket) == 0))
|
|
++Bucket;
|
|
|
|
NodePtr = static_cast<FoldingSetNode*>(*Bucket);
|
|
}
|
|
|
|
void FoldingSetIteratorImpl::advance() {
|
|
// If there is another link within this bucket, go to it.
|
|
void *Probe = NodePtr->getNextInBucket();
|
|
|
|
if (FoldingSetNode *NextNodeInBucket = GetNextPtr(Probe))
|
|
NodePtr = NextNodeInBucket;
|
|
else {
|
|
// Otherwise, this is the last link in this bucket.
|
|
void **Bucket = GetBucketPtr(Probe);
|
|
|
|
// Skip to the next non-null non-self-cycle bucket.
|
|
do {
|
|
++Bucket;
|
|
} while (*Bucket != reinterpret_cast<void*>(-1) &&
|
|
(*Bucket == 0 || GetNextPtr(*Bucket) == 0));
|
|
|
|
NodePtr = static_cast<FoldingSetNode*>(*Bucket);
|
|
}
|
|
}
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// FoldingSetBucketIteratorImpl Implementation
|
|
|
|
FoldingSetBucketIteratorImpl::FoldingSetBucketIteratorImpl(void **Bucket) {
|
|
Ptr = (*Bucket == 0 || GetNextPtr(*Bucket) == 0) ? (void*) Bucket : *Bucket;
|
|
}
|