Fix AArch64 MSan warnings #15838
Fix AArch64 MSan warnings #15838
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Yeah, all of these are false positives. I don't think we should use |
zeriyoshi
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Indeed, replaced |
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@iluuu1994 |
| result = zend_string_safe_alloc(((length + 2) / 3), 4 * sizeof(char), 0, 0); | ||
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| # if __has_feature(memory_sanitizer) | ||
| /* Clang 18 MSan does not instrument on AArch64. */ |
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This comment is not accurate. Instrumentation does happen, just not correctly. I believe it's some intrinsic calls in neon_base64_encode/neon_base64_decode that actually lack instrumentation. So, you should likely move these unpoisons there. It might also be nice to move the __msan_unpoison to zend_portability.h with a conditional macro so that we can avoid the constant #include and __has_feature(memory_sanitizer).
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Thanks, will try to move to zend_portability.h
| # if __has_feature(memory_sanitizer) | ||
| /* Clang 18 MSan does not instrument on AArch64. */ | ||
| __msan_unpoison(ZSTR_VAL(result), ZSTR_LEN(result)); | ||
| # endif |
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Clang 18 (stable) on AArch64 generates warnings about uninitialized values when using MSan.
This PR fixes the issue, but it's likely a false positive.
I'm not yet sure how to properly address the false positive, but I'm creating this draft PR for now.