summaryrefslogtreecommitdiff
path: root/llvm/lib/Support/FoldingSet.cpp
diff options
context:
space:
mode:
Diffstat (limited to 'llvm/lib/Support/FoldingSet.cpp')
-rw-r--r--llvm/lib/Support/FoldingSet.cpp463
1 files changed, 463 insertions, 0 deletions
diff --git a/llvm/lib/Support/FoldingSet.cpp b/llvm/lib/Support/FoldingSet.cpp
new file mode 100644
index 0000000000000..ce6f196e1060f
--- /dev/null
+++ b/llvm/lib/Support/FoldingSet.cpp
@@ -0,0 +1,463 @@
+//===-- Support/FoldingSet.cpp - Uniquing Hash Set --------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// 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 FoldingSetBase.
+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 is inherently unstable. Nothing should depend on the
+ // ordering of nodes in the folding set.
+ static_assert(sizeof(uintptr_t) <= sizeof(unsigned long long),
+ "unexpected pointer size");
+ AddInteger(reinterpret_cast<uintptr_t>(Ptr));
+}
+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));
+ AddInteger(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.
+ static_assert(sys::IsBigEndianHost || sys::IsLittleEndianHost,
+ "Unexpected host endianness");
+ 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 { // Little-endian host
+ 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]; LLVM_FALLTHROUGH;
+ case 2: V = (V << 8) | (unsigned char)String[Size - 2]; LLVM_FALLTHROUGH;
+ 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 FoldingSetBase.
+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 FoldingSetBase.
+
+/// 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 FoldingSetBase::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 nullptr;
+
+ return static_cast<FoldingSetBase::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**>(safe_calloc(NumBuckets + 1,
+ sizeof(void*)));
+ // Set the very last bucket to be a non-null "pointer".
+ Buckets[NumBuckets] = reinterpret_cast<void*>(-1);
+ return Buckets;
+}
+
+//===----------------------------------------------------------------------===//
+// FoldingSetBase Implementation
+
+void FoldingSetBase::anchor() {}
+
+FoldingSetBase::FoldingSetBase(unsigned Log2InitSize) {
+ assert(5 < Log2InitSize && Log2InitSize < 32 &&
+ "Initial hash table size out of range");
+ NumBuckets = 1 << Log2InitSize;
+ Buckets = AllocateBuckets(NumBuckets);
+ NumNodes = 0;
+}
+
+FoldingSetBase::FoldingSetBase(FoldingSetBase &&Arg)
+ : Buckets(Arg.Buckets), NumBuckets(Arg.NumBuckets), NumNodes(Arg.NumNodes) {
+ Arg.Buckets = nullptr;
+ Arg.NumBuckets = 0;
+ Arg.NumNodes = 0;
+}
+
+FoldingSetBase &FoldingSetBase::operator=(FoldingSetBase &&RHS) {
+ free(Buckets); // This may be null if the set is in a moved-from state.
+ Buckets = RHS.Buckets;
+ NumBuckets = RHS.NumBuckets;
+ NumNodes = RHS.NumNodes;
+ RHS.Buckets = nullptr;
+ RHS.NumBuckets = 0;
+ RHS.NumNodes = 0;
+ return *this;
+}
+
+FoldingSetBase::~FoldingSetBase() {
+ free(Buckets);
+}
+
+void FoldingSetBase::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;
+}
+
+void FoldingSetBase::GrowBucketCount(unsigned NewBucketCount) {
+ assert((NewBucketCount > NumBuckets) && "Can't shrink a folding set with GrowBucketCount");
+ assert(isPowerOf2_32(NewBucketCount) && "Bad bucket count!");
+ void **OldBuckets = Buckets;
+ unsigned OldNumBuckets = NumBuckets;
+
+ // Clear out new buckets.
+ Buckets = AllocateBuckets(NewBucketCount);
+ // Set NumBuckets only if allocation of new buckets was successful.
+ NumBuckets = NewBucketCount;
+ 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(nullptr);
+
+ // Insert the node into the new bucket, after recomputing the hash.
+ InsertNode(NodeInBucket,
+ GetBucketFor(ComputeNodeHash(NodeInBucket, TempID),
+ Buckets, NumBuckets));
+ TempID.clear();
+ }
+ }
+
+ free(OldBuckets);
+}
+
+/// GrowHashTable - Double the size of the hash table and rehash everything.
+///
+void FoldingSetBase::GrowHashTable() {
+ GrowBucketCount(NumBuckets * 2);
+}
+
+void FoldingSetBase::reserve(unsigned EltCount) {
+ // This will give us somewhere between EltCount / 2 and
+ // EltCount buckets. This puts us in the load factor
+ // range of 1.0 - 2.0.
+ if(EltCount < capacity())
+ return;
+ GrowBucketCount(PowerOf2Floor(EltCount));
+}
+
+/// FindNodeOrInsertPos - Look up the node specified by ID. If it exists,
+/// return it. If not, return the insertion token that will make insertion
+/// faster.
+FoldingSetBase::Node *
+FoldingSetBase::FindNodeOrInsertPos(const FoldingSetNodeID &ID,
+ void *&InsertPos) {
+ unsigned IDHash = ID.ComputeHash();
+ void **Bucket = GetBucketFor(IDHash, Buckets, NumBuckets);
+ void *Probe = *Bucket;
+
+ InsertPos = nullptr;
+
+ 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 nullptr;
+}
+
+/// 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 FoldingSetBase::InsertNode(Node *N, void *InsertPos) {
+ assert(!N->getNextInBucket());
+ // Do we need to grow the hashtable?
+ if (NumNodes+1 > capacity()) {
+ 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)
+ 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 FoldingSetBase::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) return false; // Not in folding set.
+
+ --NumNodes;
+ N->SetNextInBucket(nullptr);
+
+ // 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.
+FoldingSetBase::Node *FoldingSetBase::GetOrInsertNode(FoldingSetBase::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 || !GetNextPtr(*Bucket)))
+ ++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 || !GetNextPtr(*Bucket)));
+
+ NodePtr = static_cast<FoldingSetNode*>(*Bucket);
+ }
+}
+
+//===----------------------------------------------------------------------===//
+// FoldingSetBucketIteratorImpl Implementation
+
+FoldingSetBucketIteratorImpl::FoldingSetBucketIteratorImpl(void **Bucket) {
+ Ptr = (!*Bucket || !GetNextPtr(*Bucket)) ? (void*) Bucket : *Bucket;
+}
generated by cgit v1.2.3 (git 2.25.1) at 2025-11-04 00:07:13 +0000