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| author | Nathan James <n.james93@hotmail.co.uk> | 2022-07-12 23:57:03 +0100 |
|---|---|---|
| committer | Nathan James <n.james93@hotmail.co.uk> | 2022-07-12 23:57:04 +0100 |
| commit | a565509308f9372c4de1c4c32afde461a42e81c8 (patch) | |
| tree | 146b9e9d84151930ba9f9ba0b9ccede9459b495a /llvm/unittests/ADT/StringMapTest.cpp | |
| parent | 1ce3f94570eb8cca5c63a29268973bd352161c0b (diff) | |
| download | llvm-a565509308f9372c4de1c4c32afde461a42e81c8.zip llvm-a565509308f9372c4de1c4c32afde461a42e81c8.tar.gz llvm-a565509308f9372c4de1c4c32afde461a42e81c8.tar.bz2 | |
[ADT] Use Empty Base Optimization for Allocators
In D94439, BumpPtrAllocator changed its implementation to use an empty base optimization for the underlying allocator.
This patch builds on that by extending its functionality to more classes as well as enabling the underlying allocator to be a reference type, something not currently possible as you can't derive from a reference.
The main place this sees use is in StringMaps which often use the default MallocAllocator, yet have to pay the size of a pointer for no reason.
Reviewed By: dblaikie
Differential Revision: https://reviews.llvm.org/D129206
Diffstat (limited to 'llvm/unittests/ADT/StringMapTest.cpp')
| -rw-r--r-- | llvm/unittests/ADT/StringMapTest.cpp | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/llvm/unittests/ADT/StringMapTest.cpp b/llvm/unittests/ADT/StringMapTest.cpp index 817fec6..1eac07b 100644 --- a/llvm/unittests/ADT/StringMapTest.cpp +++ b/llvm/unittests/ADT/StringMapTest.cpp @@ -17,6 +17,10 @@ using namespace llvm; namespace { +static_assert(sizeof(StringMap<uint32_t>) < + sizeof(StringMap<uint32_t, MallocAllocator &>), + "Ensure empty base optimization happens with default allocator"); + // Test fixture class StringMapTest : public testing::Test { protected: |