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[SymbolTable][Perf] Use hash_combine instead of a custom hash, also use memcmp. 

ArrayRef<uint8_t>::equals(); lowers to a byte compare loop :(.

TODO: Figure out if we are getting hash collisions, or just have a lot of equal
content. Also test if crypto hashing the content instead of full compare is
better.

llvm-svn: 177588
This commit is contained in:
Michael J. Spencer 2013-03-20 22:18:22 +00:00
parent d14b6ef6ef
commit 67f25272f1
1 changed files with 9 additions and 14 deletions
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23
lld/lib/Core/SymbolTable.cpp
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@ -22,6 +22,7 @@
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/DenseMapInfo.h"
#include "llvm/ADT/Hashing.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
@ -255,22 +256,16 @@ void SymbolTable::addByName(const Atom & newAtom) {
}
}
unsigned SymbolTable::AtomMappingInfo::getHashValue(const DefinedAtom * const atom) {
unsigned hash = atom->size();
if ( atom->contentType() != DefinedAtom::typeZeroFill ) {
ArrayRef<uint8_t> content = atom->rawContent();
for (unsigned int i=0; i < content.size(); ++i) {
hash = hash * 33 + content[i];
}
}
hash &= 0x00FFFFFF;
hash |= ((unsigned)atom->contentType()) << 24;
//fprintf(stderr, "atom=%p, hash=0x%08X\n", atom, hash);
return hash;
unsigned SymbolTable::AtomMappingInfo::getHashValue(const DefinedAtom *atom) {
auto content = atom->rawContent();
return llvm::hash_combine(atom->size(),
atom->contentType(),
llvm::hash_combine_range(content.begin(),
content.end()));
}
bool SymbolTable::AtomMappingInfo::isEqual(const DefinedAtom * const l,
const DefinedAtom * const r) {
const DefinedAtom * const r) {
if ( l == r )
return true;
if ( l == getEmptyKey() )
@ -288,7 +283,7 @@ bool SymbolTable::AtomMappingInfo::isEqual(const DefinedAtom * const l,
return false;
ArrayRef<uint8_t> lc = l->rawContent();
ArrayRef<uint8_t> rc = r->rawContent();
return lc.equals(rc);
return memcmp(lc.data(), rc.data(), lc.size()) == 0;
}
void SymbolTable::addByContent(const DefinedAtom & newAtom) {