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author | 2022-04-15 13:03:39 -0700 | |
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committer | 2022-04-18 17:05:35 -0700 | |
commit | e8f03f2057ee783439229391a14b2ffe17346100 (patch) | |
tree | 49fb6dcb85ef8810c351f346b095eeff974d5460 | |
parent | [compiler-rt] Implement __clear_cache on FreeBSD/powerpc (diff) | |
download | llvm-project-e8f03f2057ee783439229391a14b2ffe17346100.tar.gz llvm-project-e8f03f2057ee783439229391a14b2ffe17346100.tar.bz2 llvm-project-e8f03f2057ee783439229391a14b2ffe17346100.zip |
Force GHashCell to be 8-byte-aligned.
Otherwise, with recent versions of libstdc++, clang can't tell that the
atomic operations are properly aligned, and generates calls to
libatomic. (Actually, because of the use of reinterpret_cast, it wasn't
guaranteed to be aligned, but I think it ended up being aligned in
practice.)
Fixes https://github.com/llvm/llvm-project/issues/54790 , the part where
LLVM failed to build.
Differential Revision: https://reviews.llvm.org/D123872
(cherry picked from commit 13fc1781735a327699d9522e8e44899acf92a61a)
-rw-r--r-- | lld/COFF/DebugTypes.cpp | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/lld/COFF/DebugTypes.cpp b/lld/COFF/DebugTypes.cpp index aa2ce3bd9bbb..0d25de464f9f 100644 --- a/lld/COFF/DebugTypes.cpp +++ b/lld/COFF/DebugTypes.cpp @@ -902,7 +902,11 @@ struct GHashTable { /// A ghash table cell for deduplicating types from TpiSources. class GHashCell { - uint64_t data = 0; + // Force "data" to be 64-bit aligned; otherwise, some versions of clang + // will generate calls to libatomic when using some versions of libstdc++ + // on 32-bit targets. (Also, in theory, there could be a target where + // new[] doesn't always return an 8-byte-aligned allocation.) + alignas(sizeof(uint64_t)) uint64_t data = 0; public: GHashCell() = default; |