--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lib/Support/FoldingSet.cpp	Thu Dec 12 13:56:28 2013 +0900
@@ -0,0 +1,424 @@
+//===-- 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.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ADT/FoldingSet.h"
+#include "llvm/ADT/Hashing.h"
+#include "llvm/Support/Allocator.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/Host.h"
+#include "llvm/Support/MathExtras.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 {
+  return static_cast<unsigned>(hash_combine_range(Data, Data+Size));
+}
+
+bool FoldingSetNodeIDRef::operator==(FoldingSetNodeIDRef RHS) const {
+  if (Size != RHS.Size) return false;
+  return memcmp(Data, RHS.Data, Size*sizeof(*Data)) == 0;
+}
+
+/// Used to compare the "ordering" of two nodes as defined by the
+/// profiled bits and their ordering defined by memcmp().
+bool FoldingSetNodeIDRef::operator<(FoldingSetNodeIDRef RHS) const {
+  if (Size != RHS.Size)
+    return Size < RHS.Size;
+  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.
+  Bits.append(reinterpret_cast<unsigned *>(&Ptr),
+              reinterpret_cast<unsigned *>(&Ptr+1));
+}
+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)(unsigned)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;
+}
+
+/// Used to compare the "ordering" of two nodes as defined by the
+/// profiled bits and their ordering defined by memcmp().
+bool FoldingSetNodeID::operator<(const FoldingSetNodeID &RHS) const {
+  return *this < FoldingSetNodeIDRef(RHS.Bits.data(), RHS.Bits.size());
+}
+
+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) {
+  unsigned IDHash = ID.ComputeHash();
+  void **Bucket = GetBucketFor(IDHash, Buckets, NumBuckets);
+  void *Probe = *Bucket;
+  
+  InsertPos = 0;
+  
+  FoldingSetNodeID TempID;
+  while (Node *NodeInBucket = GetNextPtr(Probe)) {
+    if (NodeEquals(NodeInBucket, ID, IDHash, 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;
+}