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Diffstat (limited to 'contrib/llvm/lib/Support/SmallPtrSet.cpp')
-rw-r--r-- | contrib/llvm/lib/Support/SmallPtrSet.cpp | 281 |
1 files changed, 281 insertions, 0 deletions
diff --git a/contrib/llvm/lib/Support/SmallPtrSet.cpp b/contrib/llvm/lib/Support/SmallPtrSet.cpp new file mode 100644 index 0000000..3b53e9f --- /dev/null +++ b/contrib/llvm/lib/Support/SmallPtrSet.cpp @@ -0,0 +1,281 @@ +//===- llvm/ADT/SmallPtrSet.cpp - 'Normally small' pointer set ------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file implements the SmallPtrSet class. See SmallPtrSet.h for an +// overview of the algorithm. +// +//===----------------------------------------------------------------------===// + +#include "llvm/ADT/SmallPtrSet.h" +#include "llvm/ADT/DenseMapInfo.h" +#include "llvm/Support/MathExtras.h" +#include <algorithm> +#include <cstdlib> + +using namespace llvm; + +void SmallPtrSetImpl::shrink_and_clear() { + assert(!isSmall() && "Can't shrink a small set!"); + free(CurArray); + + // Reduce the number of buckets. + CurArraySize = NumElements > 16 ? 1 << (Log2_32_Ceil(NumElements) + 1) : 32; + NumElements = NumTombstones = 0; + + // Install the new array. Clear all the buckets to empty. + CurArray = (const void**)malloc(sizeof(void*) * (CurArraySize+1)); + assert(CurArray && "Failed to allocate memory?"); + memset(CurArray, -1, CurArraySize*sizeof(void*)); + + // The end pointer, always valid, is set to a valid element to help the + // iterator. + CurArray[CurArraySize] = 0; +} + +bool SmallPtrSetImpl::insert_imp(const void * Ptr) { + if (isSmall()) { + // Check to see if it is already in the set. + for (const void **APtr = SmallArray, **E = SmallArray+NumElements; + APtr != E; ++APtr) + if (*APtr == Ptr) + return false; + + // Nope, there isn't. If we stay small, just 'pushback' now. + if (NumElements < CurArraySize-1) { + SmallArray[NumElements++] = Ptr; + return true; + } + // Otherwise, hit the big set case, which will call grow. + } + + if (NumElements*4 >= CurArraySize*3) { + // If more than 3/4 of the array is full, grow. + Grow(CurArraySize < 64 ? 128 : CurArraySize*2); + } else if (CurArraySize-(NumElements+NumTombstones) < CurArraySize/8) { + // If fewer of 1/8 of the array is empty (meaning that many are filled with + // tombstones), rehash. + Grow(CurArraySize); + } + + // Okay, we know we have space. Find a hash bucket. + const void **Bucket = const_cast<const void**>(FindBucketFor(Ptr)); + if (*Bucket == Ptr) return false; // Already inserted, good. + + // Otherwise, insert it! + if (*Bucket == getTombstoneMarker()) + --NumTombstones; + *Bucket = Ptr; + ++NumElements; // Track density. + return true; +} + +bool SmallPtrSetImpl::erase_imp(const void * Ptr) { + if (isSmall()) { + // Check to see if it is in the set. + for (const void **APtr = SmallArray, **E = SmallArray+NumElements; + APtr != E; ++APtr) + if (*APtr == Ptr) { + // If it is in the set, replace this element. + *APtr = E[-1]; + E[-1] = getEmptyMarker(); + --NumElements; + return true; + } + + return false; + } + + // Okay, we know we have space. Find a hash bucket. + void **Bucket = const_cast<void**>(FindBucketFor(Ptr)); + if (*Bucket != Ptr) return false; // Not in the set? + + // Set this as a tombstone. + *Bucket = getTombstoneMarker(); + --NumElements; + ++NumTombstones; + return true; +} + +const void * const *SmallPtrSetImpl::FindBucketFor(const void *Ptr) const { + unsigned Bucket = DenseMapInfo<void *>::getHashValue(Ptr) & (CurArraySize-1); + unsigned ArraySize = CurArraySize; + unsigned ProbeAmt = 1; + const void *const *Array = CurArray; + const void *const *Tombstone = 0; + while (1) { + // Found Ptr's bucket? + if (Array[Bucket] == Ptr) + return Array+Bucket; + + // If we found an empty bucket, the pointer doesn't exist in the set. + // Return a tombstone if we've seen one so far, or the empty bucket if + // not. + if (Array[Bucket] == getEmptyMarker()) + return Tombstone ? Tombstone : Array+Bucket; + + // If this is a tombstone, remember it. If Ptr ends up not in the set, we + // prefer to return it than something that would require more probing. + if (Array[Bucket] == getTombstoneMarker() && !Tombstone) + Tombstone = Array+Bucket; // Remember the first tombstone found. + + // It's a hash collision or a tombstone. Reprobe. + Bucket = (Bucket + ProbeAmt++) & (ArraySize-1); + } +} + +/// Grow - Allocate a larger backing store for the buckets and move it over. +/// +void SmallPtrSetImpl::Grow(unsigned NewSize) { + // Allocate at twice as many buckets, but at least 128. + unsigned OldSize = CurArraySize; + + const void **OldBuckets = CurArray; + bool WasSmall = isSmall(); + + // Install the new array. Clear all the buckets to empty. + CurArray = (const void**)malloc(sizeof(void*) * (NewSize+1)); + assert(CurArray && "Failed to allocate memory?"); + CurArraySize = NewSize; + memset(CurArray, -1, NewSize*sizeof(void*)); + + // The end pointer, always valid, is set to a valid element to help the + // iterator. + CurArray[NewSize] = 0; + + // Copy over all the elements. + if (WasSmall) { + // Small sets store their elements in order. + for (const void **BucketPtr = OldBuckets, **E = OldBuckets+NumElements; + BucketPtr != E; ++BucketPtr) { + const void *Elt = *BucketPtr; + *const_cast<void**>(FindBucketFor(Elt)) = const_cast<void*>(Elt); + } + } else { + // Copy over all valid entries. + for (const void **BucketPtr = OldBuckets, **E = OldBuckets+OldSize; + BucketPtr != E; ++BucketPtr) { + // Copy over the element if it is valid. + const void *Elt = *BucketPtr; + if (Elt != getTombstoneMarker() && Elt != getEmptyMarker()) + *const_cast<void**>(FindBucketFor(Elt)) = const_cast<void*>(Elt); + } + + free(OldBuckets); + NumTombstones = 0; + } +} + +SmallPtrSetImpl::SmallPtrSetImpl(const void **SmallStorage, + const SmallPtrSetImpl& that) { + SmallArray = SmallStorage; + + // If we're becoming small, prepare to insert into our stack space + if (that.isSmall()) { + CurArray = SmallArray; + // Otherwise, allocate new heap space (unless we were the same size) + } else { + CurArray = (const void**)malloc(sizeof(void*) * (that.CurArraySize+1)); + assert(CurArray && "Failed to allocate memory?"); + } + + // Copy over the new array size + CurArraySize = that.CurArraySize; + + // Copy over the contents from the other set + memcpy(CurArray, that.CurArray, sizeof(void*)*(CurArraySize+1)); + + NumElements = that.NumElements; + NumTombstones = that.NumTombstones; +} + +/// CopyFrom - implement operator= from a smallptrset that has the same pointer +/// type, but may have a different small size. +void SmallPtrSetImpl::CopyFrom(const SmallPtrSetImpl &RHS) { + if (isSmall() && RHS.isSmall()) + assert(CurArraySize == RHS.CurArraySize && + "Cannot assign sets with different small sizes"); + + // If we're becoming small, prepare to insert into our stack space + if (RHS.isSmall()) { + if (!isSmall()) + free(CurArray); + CurArray = SmallArray; + // Otherwise, allocate new heap space (unless we were the same size) + } else if (CurArraySize != RHS.CurArraySize) { + if (isSmall()) + CurArray = (const void**)malloc(sizeof(void*) * (RHS.CurArraySize+1)); + else + CurArray = (const void**)realloc(CurArray, sizeof(void*)*(RHS.CurArraySize+1)); + assert(CurArray && "Failed to allocate memory?"); + } + + // Copy over the new array size + CurArraySize = RHS.CurArraySize; + + // Copy over the contents from the other set + memcpy(CurArray, RHS.CurArray, sizeof(void*)*(CurArraySize+1)); + + NumElements = RHS.NumElements; + NumTombstones = RHS.NumTombstones; +} + +void SmallPtrSetImpl::swap(SmallPtrSetImpl &RHS) { + if (this == &RHS) return; + + // We can only avoid copying elements if neither set is small. + if (!this->isSmall() && !RHS.isSmall()) { + std::swap(this->CurArray, RHS.CurArray); + std::swap(this->CurArraySize, RHS.CurArraySize); + std::swap(this->NumElements, RHS.NumElements); + std::swap(this->NumTombstones, RHS.NumTombstones); + return; + } + + // FIXME: From here on we assume that both sets have the same small size. + + // If only RHS is small, copy the small elements into LHS and move the pointer + // from LHS to RHS. + if (!this->isSmall() && RHS.isSmall()) { + std::copy(RHS.SmallArray, RHS.SmallArray+RHS.CurArraySize, + this->SmallArray); + std::swap(this->NumElements, RHS.NumElements); + std::swap(this->CurArraySize, RHS.CurArraySize); + RHS.CurArray = this->CurArray; + RHS.NumTombstones = this->NumTombstones; + this->CurArray = this->SmallArray; + this->NumTombstones = 0; + return; + } + + // If only LHS is small, copy the small elements into RHS and move the pointer + // from RHS to LHS. + if (this->isSmall() && !RHS.isSmall()) { + std::copy(this->SmallArray, this->SmallArray+this->CurArraySize, + RHS.SmallArray); + std::swap(RHS.NumElements, this->NumElements); + std::swap(RHS.CurArraySize, this->CurArraySize); + this->CurArray = RHS.CurArray; + this->NumTombstones = RHS.NumTombstones; + RHS.CurArray = RHS.SmallArray; + RHS.NumTombstones = 0; + return; + } + + // Both a small, just swap the small elements. + assert(this->isSmall() && RHS.isSmall()); + assert(this->CurArraySize == RHS.CurArraySize); + std::swap_ranges(this->SmallArray, this->SmallArray+this->CurArraySize, + RHS.SmallArray); + std::swap(this->NumElements, RHS.NumElements); +} + +SmallPtrSetImpl::~SmallPtrSetImpl() { + if (!isSmall()) + free(CurArray); +} |