Check in LLVM r95781.
diff --git a/lib/Support/FoldingSet.cpp b/lib/Support/FoldingSet.cpp
new file mode 100644
index 0000000..954dc77
--- /dev/null
+++ b/lib/Support/FoldingSet.cpp
@@ -0,0 +1,371 @@
+//===-- 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/ErrorHandling.h"
+#include "llvm/Support/MathExtras.h"
+#include <cassert>
+#include <cstring>
+using namespace llvm;
+
+//===----------------------------------------------------------------------===//
+// 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.
+ 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);
+ }
+ }
+
+ // With the leftover bits.
+ unsigned V = 0;
+ // Pos will have overshot size by 4 - #bytes left over.
+ 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);
+}
+
+/// ComputeHash - Compute a strong hash value for this FoldingSetNodeID, used to
+/// lookup the node in the FoldingSetImpl.
+unsigned FoldingSetNodeID::ComputeHash() const {
+ // This is adapted from SuperFastHash by Paul Hsieh.
+ unsigned Hash = static_cast<unsigned>(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 FoldingSetNodeID::operator==(const FoldingSetNodeID &RHS)const{
+ if (Bits.size() != RHS.Bits.size()) return false;
+ return memcmp(&Bits[0], &RHS.Bits[0], Bits.size()*sizeof(Bits[0])) == 0;
+}
+
+
+//===----------------------------------------------------------------------===//
+/// 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(const FoldingSetNodeID &ID,
+ void **Buckets, unsigned NumBuckets) {
+ // NumBuckets is always a power of 2.
+ unsigned BucketNum = ID.ComputeHash() & (NumBuckets-1);
+ return Buckets + BucketNum;
+}
+
+//===----------------------------------------------------------------------===//
+// FoldingSetImpl Implementation
+
+FoldingSetImpl::FoldingSetImpl(unsigned Log2InitSize) {
+ assert(5 < Log2InitSize && Log2InitSize < 32 &&
+ "Initial hash table size out of range");
+ NumBuckets = 1 << Log2InitSize;
+ Buckets = new void*[NumBuckets+1];
+ clear();
+}
+FoldingSetImpl::~FoldingSetImpl() {
+ delete [] 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 = new void*[NumBuckets+1];
+ clear();
+
+ // Walk the old buckets, rehashing nodes into their new place.
+ FoldingSetNodeID ID;
+ 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.
+ GetNodeProfile(ID, NodeInBucket);
+ InsertNode(NodeInBucket, GetBucketFor(ID, Buckets, NumBuckets));
+ ID.clear();
+ }
+ }
+
+ 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 FoldingSetNodeID &ID,
+ void *&InsertPos) {
+
+ void **Bucket = GetBucketFor(ID, Buckets, NumBuckets);
+ void *Probe = *Bucket;
+
+ InsertPos = 0;
+
+ FoldingSetNodeID OtherID;
+ while (Node *NodeInBucket = GetNextPtr(Probe)) {
+ GetNodeProfile(OtherID, NodeInBucket);
+ if (OtherID == ID)
+ return NodeInBucket;
+
+ Probe = NodeInBucket->getNextInBucket();
+ OtherID.clear();
+ }
+
+ // 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 ID;
+ GetNodeProfile(ID, N);
+ InsertPos = GetBucketFor(ID, 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(ID, N);
+ 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;
+}