[PATCH] D95654: ADT: Sink the guts of StringMapEntry::Create into StringMapEntryBase
Duncan P. N. Exon Smith via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Thu Jan 28 17:46:42 PST 2021
dexonsmith created this revision.
dexonsmith added a reviewer: dblaikie.
Herald added a subscriber: ributzka.
dexonsmith requested review of this revision.
Herald added a project: LLVM.
Sink the interesting parts of StringMapEntry::Create into a new function
StringMapEntryBase::allocateWithKey that's only templated on the
allocator, taking the entry size and alignment as parameters.
I double-checked this doesn't impact clang's compile time performance here:
https://llvm-compile-time-tracker.com/compare.php?from=2d430f902d72b8a1d3bc036a80273ca80af1e338&to=63e5ea3bf2a2b59508e452aee6a9dc0eb369f527&stat=instructions
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D95654
Files:
llvm/include/llvm/ADT/StringMapEntry.h
Index: llvm/include/llvm/ADT/StringMapEntry.h
===================================================================
--- llvm/include/llvm/ADT/StringMapEntry.h
+++ llvm/include/llvm/ADT/StringMapEntry.h
@@ -27,8 +27,34 @@
explicit StringMapEntryBase(size_t keyLength) : keyLength(keyLength) {}
size_t getKeyLength() const { return keyLength; }
+
+protected:
+ template <typename AllocatorTy>
+ static void *allocateWithKey(size_t EntrySize, size_t EntryAlign,
+ StringRef Key, AllocatorTy &Allocator);
};
+// Define out-of-line to dissuade inlining.
+template <typename AllocatorTy>
+void *StringMapEntryBase::allocateWithKey(size_t EntrySize, size_t EntryAlign,
+ StringRef Key,
+ AllocatorTy &Allocator) {
+ size_t KeyLength = Key.size();
+
+ // Allocate a new item with space for the string at the end and a null
+ // terminator.
+ size_t AllocSize = EntrySize + KeyLength + 1;
+ void *Allocation = Allocator.Allocate(AllocSize, EntryAlign);
+ assert(Allocation && "Unhandled out-of-memory");
+
+ // Copy the string information.
+ char *Buffer = reinterpret_cast<char *>(Allocation) + EntrySize;
+ if (KeyLength > 0)
+ ::memcpy(Buffer, Key.data(), KeyLength);
+ Buffer[KeyLength] = 0; // Null terminate for convenience of clients.
+ return Allocation;
+}
+
/// StringMapEntryStorage - Holds the value in a StringMapEntry.
///
/// Factored out into a separate base class to make it easier to specialize.
@@ -90,26 +116,9 @@
template <typename AllocatorTy, typename... InitTy>
static StringMapEntry *Create(StringRef key, AllocatorTy &allocator,
InitTy &&... initVals) {
- size_t keyLength = key.size();
-
- // Allocate a new item with space for the string at the end and a null
- // terminator.
- size_t allocSize = sizeof(StringMapEntry) + keyLength + 1;
- size_t alignment = alignof(StringMapEntry);
-
- StringMapEntry *newItem =
- static_cast<StringMapEntry *>(allocator.Allocate(allocSize, alignment));
- assert(newItem && "Unhandled out-of-memory");
-
- // Construct the value.
- new (newItem) StringMapEntry(keyLength, std::forward<InitTy>(initVals)...);
-
- // Copy the string information.
- char *strBuffer = const_cast<char *>(newItem->getKeyData());
- if (keyLength > 0)
- memcpy(strBuffer, key.data(), keyLength);
- strBuffer[keyLength] = 0; // Null terminate for convenience of clients.
- return newItem;
+ return new (StringMapEntryBase::allocateWithKey(
+ sizeof(StringMapEntry), alignof(StringMapEntry), key, allocator))
+ StringMapEntry(key.size(), std::forward<InitTy>(initVals)...);
}
/// GetStringMapEntryFromKeyData - Given key data that is known to be embedded
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