Changes in directory llvm/lib/Support:
FoldingSet.cpp added (r1.1)
---
Log message:
Breakout folding hash set from SelectionDAGCSEMap.
---
Diffs of the changes: (+282 -0)
FoldingSet.cpp | 282 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 282 insertions(+)
Index: llvm/lib/Support/FoldingSet.cpp
diff -c /dev/null llvm/lib/Support/FoldingSet.cpp:1.1
*** /dev/null Fri Oct 27 11:16:26 2006
--- llvm/lib/Support/FoldingSet.cpp Fri Oct 27 11:16:16 2006
***************
*** 0 ****
--- 1,282 ----
+ //===-- Support/FoldingSet.cpp - Uniquing Hash Set --------------*- C++
-*-===//
+ //
+ // The LLVM Compiler Infrastructure
+ //
+ // This file was developed by James M. Laskey and 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/ADT/MathExtras.h"
+
+ using namespace llvm;
+
+
//===----------------------------------------------------------------------===//
+ // FoldingSetImpl::NodeID Implementation
+
+ /// Add* - Add various data types to Bit data.
+ ///
+ void FoldingSetImpl::NodeID::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 FoldingSetImpl::NodeID::AddInteger(signed I) {
+ Bits.push_back(I);
+ }
+ void FoldingSetImpl::NodeID::AddInteger(unsigned I) {
+ Bits.push_back(I);
+ }
+ void FoldingSetImpl::NodeID::AddInteger(uint64_t I) {
+ Bits.push_back(unsigned(I));
+ Bits.push_back(unsigned(I >> 32));
+ }
+ void FoldingSetImpl::NodeID::AddFloat(float F) {
+ Bits.push_back(FloatToBits(F));
+ }
+ void FoldingSetImpl::NodeID::AddDouble(double D) {
+ Bits.push_back(DoubleToBits(D));
+ }
+ void FoldingSetImpl::NodeID::AddString(const std::string &String) {
+ // Note: An assumption is made here that strings are composed of one byte
+ // chars.
+ unsigned Size = String.size();
+ unsigned Units = Size / sizeof(unsigned);
+ const unsigned *Base = (const unsigned *)String.data();
+ Bits.insert(Bits.end(), Base, Base + Units);
+ if (Size & 3) {
+ unsigned V = 0;
+ for (unsigned i = Units * sizeof(unsigned); i < Size; ++i)
+ V = (V << 8) | String[i];
+ Bits.push_back(V);
+ }
+ }
+
+ /// ComputeHash - Compute a strong hash value for this NodeID, used to
+ /// lookup the node in the FoldingSetImpl.
+ unsigned FoldingSetImpl::NodeID::ComputeHash() const {
+ // This is adapted from SuperFastHash by Paul Hsieh.
+ unsigned Hash = Bits.size();
+ for (const unsigned *BP = &Bits[0], *E = BP+Bits.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;
+ }
+
+ /// operator== - Used to compare two nodes to each other.
+ ///
+ bool FoldingSetImpl::NodeID::operator==(const FoldingSetImpl::NodeID
&RHS)const{
+ if (Bits.size() != RHS.Bits.size()) return false;
+ return memcmp(&Bits[0], &RHS.Bits[0], Bits.size()*sizeof(Bits[0])) == 0;
+ }
+
+
+
//===----------------------------------------------------------------------===//
+ // FoldingSetImpl Implementation
+
+ FoldingSetImpl::FoldingSetImpl() : NumNodes(0) {
+ NumBuckets = 64;
+ Buckets = new void*[NumBuckets];
+ memset(Buckets, 0, NumBuckets*sizeof(void*));
+ }
+ FoldingSetImpl::~FoldingSetImpl() {
+ delete [] Buckets;
+ }
+
+ /// 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.
+ FoldingSetImpl::Node *FoldingSetImpl::GetNextPtr(void *NextInBucketPtr) {
+ if (NextInBucketPtr >= Buckets && NextInBucketPtr < Buckets+NumBuckets)
+ return 0;
+ return static_cast<Node*>(NextInBucketPtr);
+ }
+
+ /// GetNextPtr - This is just like the previous GetNextPtr implementation,
+ /// but allows a bucket array to be specified.
+ FoldingSetImpl::Node *FoldingSetImpl::GetNextPtr(void *NextInBucketPtr,
+ void **Bucks,
+ unsigned NumBuck) {
+ if (NextInBucketPtr >= Bucks && NextInBucketPtr < Bucks+NumBuck)
+ return 0;
+ return static_cast<Node*>(NextInBucketPtr);
+ }
+
+ /// GetBucketPtr - Provides a casting of a bucket pointer for isNode
+ /// testing.
+ void **FoldingSetImpl::GetBucketPtr(void *NextInBucketPtr) {
+ return static_cast<void**>(NextInBucketPtr);
+ }
+
+ /// GetBucketFor - Hash the specified node ID and return the hash bucket for
+ /// the specified ID.
+ void **FoldingSetImpl::GetBucketFor(const NodeID &ID) const {
+ // NumBuckets is always a power of 2.
+ unsigned BucketNum = ID.ComputeHash() & (NumBuckets-1);
+ return Buckets+BucketNum;
+ }
+
+ /// GrowHashTable - Double the size of the hash table and rehash everything.
+ ///
+ void FoldingSetImpl::GrowHashTable() {
+ void **OldBuckets = Buckets;
+ unsigned OldNumBuckets = NumBuckets;
+ NumBuckets <<= 1;
+
+ // Reset the node count to zero: we're going to reinsert everything.
+ NumNodes = 0;
+
+ // Clear out new buckets.
+ Buckets = new void*[NumBuckets];
+ memset(Buckets, 0, NumBuckets*sizeof(void*));
+
+ // Walk the old buckets, rehashing nodes into their new place.
+ for (unsigned i = 0; i != OldNumBuckets; ++i) {
+ void *Probe = OldBuckets[i];
+ if (!Probe) continue;
+ while (Node *NodeInBucket = GetNextPtr(Probe, OldBuckets, OldNumBuckets)){
+ // 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.
+ NodeID ID;
+ GetNodeProfile(ID, NodeInBucket);
+ InsertNode(NodeInBucket, GetBucketFor(ID));
+ }
+ }
+
+ delete[] 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 NodeID &ID,
+ void *&InsertPos) {
+ void **Bucket = GetBucketFor(ID);
+ void *Probe = *Bucket;
+
+ InsertPos = 0;
+
+ while (Node *NodeInBucket = GetNextPtr(Probe)) {
+ NodeID OtherID;
+ GetNodeProfile(OtherID, NodeInBucket);
+ if (OtherID == ID)
+ return NodeInBucket;
+
+ 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) {
+ ++NumNodes;
+ // Do we need to grow the hashtable?
+ if (NumNodes > NumBuckets*2) {
+ GrowHashTable();
+ NodeID ID;
+ GetNodeProfile(ID, N);
+ InsertPos = GetBucketFor(ID);
+ }
+
+ /// 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.
+ if (Next == 0)
+ Next = Bucket;
+
+ // Set the nodes 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. Chase around the list until we find the node (or bucket)
+ // which points to N.
+ void *Ptr = N->getNextInBucket();
+ if (Ptr == 0) return false; // Not in folding set.
+
+ --NumNodes;
+
+ void *NodeNextPtr = Ptr;
+ N->SetNextInBucket(0);
+ 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) {
+ NodeID ID;
+ GetNodeProfile(ID, N);
+ void *IP;
+ if (Node *E = FindNodeOrInsertPos(ID, IP))
+ return E;
+ InsertNode(N, IP);
+ return N;
+ }
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