diff options
Diffstat (limited to 'llvm/lib/Support/StringMap.cpp')
-rw-r--r-- | llvm/lib/Support/StringMap.cpp | 39 |
1 files changed, 20 insertions, 19 deletions
diff --git a/llvm/lib/Support/StringMap.cpp b/llvm/lib/Support/StringMap.cpp index 9382c3ce29e..79262cc6d3a 100644 --- a/llvm/lib/Support/StringMap.cpp +++ b/llvm/lib/Support/StringMap.cpp @@ -14,6 +14,7 @@ #include "llvm/ADT/StringMap.h" #include "llvm/ADT/StringExtras.h" #include "llvm/Support/Compiler.h" +#include "llvm/Support/DJB.h" #include "llvm/Support/MathExtras.h" #include <cassert> @@ -32,7 +33,7 @@ static unsigned getMinBucketToReserveForEntries(unsigned NumEntries) { StringMapImpl::StringMapImpl(unsigned InitSize, unsigned itemSize) { ItemSize = itemSize; - + // If a size is specified, initialize the table with that many buckets. if (InitSize) { // The table will grow when the number of entries reach 3/4 of the number of @@ -41,7 +42,7 @@ StringMapImpl::StringMapImpl(unsigned InitSize, unsigned itemSize) { init(getMinBucketToReserveForEntries(InitSize)); return; } - + // Otherwise, initialize it with zero buckets to avoid the allocation. TheTable = nullptr; NumBuckets = 0; @@ -56,7 +57,7 @@ void StringMapImpl::init(unsigned InitSize) { unsigned NewNumBuckets = InitSize ? InitSize : 16; NumItems = 0; NumTombstones = 0; - + TheTable = static_cast<StringMapEntryBase **>( std::calloc(NewNumBuckets+1, sizeof(StringMapEntryBase **) + sizeof(unsigned))); @@ -82,7 +83,7 @@ unsigned StringMapImpl::LookupBucketFor(StringRef Name) { init(16); HTSize = NumBuckets; } - unsigned FullHashValue = HashString(Name); + unsigned FullHashValue = djbHash(Name, 0); unsigned BucketNo = FullHashValue & (HTSize-1); unsigned *HashTable = (unsigned *)(TheTable + NumBuckets + 1); @@ -98,11 +99,11 @@ unsigned StringMapImpl::LookupBucketFor(StringRef Name) { HashTable[FirstTombstone] = FullHashValue; return FirstTombstone; } - + HashTable[BucketNo] = FullHashValue; return BucketNo; } - + if (BucketItem == getTombstoneVal()) { // Skip over tombstones. However, remember the first one we see. if (FirstTombstone == -1) FirstTombstone = BucketNo; @@ -111,7 +112,7 @@ unsigned StringMapImpl::LookupBucketFor(StringRef Name) { // case here is that we are only looking at the buckets (for item info // being non-null and for the full hash value) not at the items. This // is important for cache locality. - + // Do the comparison like this because Name isn't necessarily // null-terminated! char *ItemStr = (char*)BucketItem+ItemSize; @@ -120,10 +121,10 @@ unsigned StringMapImpl::LookupBucketFor(StringRef Name) { return BucketNo; } } - + // Okay, we didn't find the item. Probe to the next bucket. BucketNo = (BucketNo+ProbeAmt) & (HTSize-1); - + // Use quadratic probing, it has fewer clumping artifacts than linear // probing and has good cache behavior in the common case. ++ProbeAmt; @@ -136,7 +137,7 @@ unsigned StringMapImpl::LookupBucketFor(StringRef Name) { int StringMapImpl::FindKey(StringRef Key) const { unsigned HTSize = NumBuckets; if (HTSize == 0) return -1; // Really empty table? - unsigned FullHashValue = HashString(Key); + unsigned FullHashValue = djbHash(Key, 0); unsigned BucketNo = FullHashValue & (HTSize-1); unsigned *HashTable = (unsigned *)(TheTable + NumBuckets + 1); @@ -146,7 +147,7 @@ int StringMapImpl::FindKey(StringRef Key) const { // If we found an empty bucket, this key isn't in the table yet, return. if (LLVM_LIKELY(!BucketItem)) return -1; - + if (BucketItem == getTombstoneVal()) { // Ignore tombstones. } else if (LLVM_LIKELY(HashTable[BucketNo] == FullHashValue)) { @@ -154,7 +155,7 @@ int StringMapImpl::FindKey(StringRef Key) const { // case here is that we are only looking at the buckets (for item info // being non-null and for the full hash value) not at the items. This // is important for cache locality. - + // Do the comparison like this because NameStart isn't necessarily // null-terminated! char *ItemStr = (char*)BucketItem+ItemSize; @@ -163,10 +164,10 @@ int StringMapImpl::FindKey(StringRef Key) const { return BucketNo; } } - + // Okay, we didn't find the item. Probe to the next bucket. BucketNo = (BucketNo+ProbeAmt) & (HTSize-1); - + // Use quadratic probing, it has fewer clumping artifacts than linear // probing and has good cache behavior in the common case. ++ProbeAmt; @@ -187,7 +188,7 @@ void StringMapImpl::RemoveKey(StringMapEntryBase *V) { StringMapEntryBase *StringMapImpl::RemoveKey(StringRef Key) { int Bucket = FindKey(Key); if (Bucket == -1) return nullptr; - + StringMapEntryBase *Result = TheTable[Bucket]; TheTable[Bucket] = getTombstoneVal(); --NumItems; @@ -241,13 +242,13 @@ unsigned StringMapImpl::RehashTable(unsigned BucketNo) { NewBucketNo = NewBucket; continue; } - + // Otherwise probe for a spot. unsigned ProbeSize = 1; do { NewBucket = (NewBucket + ProbeSize++) & (NewSize-1); } while (NewTableArray[NewBucket]); - + // Finally found a slot. Fill it in. NewTableArray[NewBucket] = Bucket; NewHashArray[NewBucket] = FullHash; @@ -255,9 +256,9 @@ unsigned StringMapImpl::RehashTable(unsigned BucketNo) { NewBucketNo = NewBucket; } } - + free(TheTable); - + TheTable = NewTableArray; NumBuckets = NewSize; NumTombstones = 0; |