From dfe91cefd25614bc9ac1626d67df4d5ad5d3553f Mon Sep 17 00:00:00 2001 From: Daniel Dunbar Date: Fri, 15 Mar 2013 20:16:59 +0000 Subject: [PATCH] [ADT] Fix StringSet::insert() to not allocate on every lookup. - The previous implementation always constructed the StringMap entry, even if the key was present in the set. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177178 91177308-0d34-0410-b5e6-96231b3b80d8 --- include/llvm/ADT/StringSet.h | 26 ++++++++++++++------------ 1 file changed, 14 insertions(+), 12 deletions(-) diff --git a/include/llvm/ADT/StringSet.h b/include/llvm/ADT/StringSet.h index b69a964a23b..7bea577f34d 100644 --- a/include/llvm/ADT/StringSet.h +++ b/include/llvm/ADT/StringSet.h @@ -18,23 +18,25 @@ namespace llvm { - /// StringSet - A wrapper for StringMap that provides set-like - /// functionality. Only insert() and count() methods are used by my - /// code. + /// StringSet - A wrapper for StringMap that provides set-like functionality. template class StringSet : public llvm::StringMap { typedef llvm::StringMap base; public: - bool insert(StringRef InLang) { - assert(!InLang.empty()); - const char *KeyStart = InLang.data(); - const char *KeyEnd = KeyStart + InLang.size(); - llvm::StringMapEntry *Entry = llvm::StringMapEntry:: - Create(KeyStart, KeyEnd, base::getAllocator(), '+'); - if (!base::insert(Entry)) { - Entry->Destroy(base::getAllocator()); + + /// insert - Insert the specified key into the set. If the key already + /// exists in the set, return false and ignore the request, otherwise insert + /// it and return true. + bool insert(StringRef Key) { + // Get or create the map entry for the key; if it doesn't exist the value + // type will be default constructed which we use to detect insert. + // + // We use '+' as the sentinel value in the map. + assert(!Key.empty()); + StringMapEntry &Entry = this->GetOrCreateValue(Key); + if (Entry.getValue() == '+') return false; - } + Entry.setValue('+'); return true; } }; -- 2.34.1