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ab11e9c0f7
Why: several hot paths used legacy atomic idioms where read-only and weak state observations paid unnecessary synchronization cost or used mutex fallbacks in signal-sensitive paths. Impact: common counters and weak flags use cheaper atomic operations on modern compilers while preserving fallback behavior for older platforms. Before/After: before, helpers leaned on __sync fetch operations and some signal flags used mutex-backed access; after, helpers use __atomic operations with explicit relaxed/acquire/release intent and signal-safe weak flag access. Technical Overview: Replace legacy __sync-based helper implementations with __atomic forms. Remove the now-unused separate load/store autoconf probe. Add relaxed helper variants for statistics and weak object state paths. Use PREFER_* helpers for signal-observed flags that tolerate weak fallback reads. Keep bHadHUP set until doHUP() completes for imdiag AwaitHUPComplete. Preserve 64-bit/time_t fallback mutexes for platforms without 64-bit atomics. Adjust sanitizer suppressions for known helper-access false positives. Join tcpsrv and imbeats workers before tearing down shared listener state. Add a small mmutf8fix regression coverage improvement touched by this work. With the help of AI-Agents: Codex
61 lines
1.7 KiB
Plaintext
61 lines
1.7 KiB
Plaintext
# rsyslog
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#
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# atomic_operations.m4 - autoconf macro to check if compiler supports atomic
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# operations
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#
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# rgerhards, 2008-09-18, added based on
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# http://svn.apache.org/repos/asf/apr/apr/trunk/configure.in
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#
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#
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AC_DEFUN([RS_ATOMIC_OPERATIONS_64BIT],
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[AC_CACHE_CHECK([whether the compiler provides atomic builtins for 64 bit data types], [ap_cv_atomic_builtins_64],
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[AC_TRY_RUN([
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int main()
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{
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unsigned long long val = 1010, tmp, *mem = &val;
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void *ptr = &val, *expected_ptr, *new_ptr;
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if (__atomic_fetch_add(&val, 1010, __ATOMIC_SEQ_CST) != 1010 || val != 2020)
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return 1;
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tmp = val;
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if (__atomic_fetch_sub(mem, 1010, __ATOMIC_SEQ_CST) != tmp || val != 1010)
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return 1;
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if (__atomic_sub_fetch(&val, 1010, __ATOMIC_SEQ_CST) != 0 || val != 0)
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return 1;
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tmp = 3030;
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{
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unsigned long long expected = 0;
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if (!__atomic_compare_exchange_n(mem, &expected, tmp, 0,
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__ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST) ||
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val != tmp)
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return 1;
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}
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__atomic_store_n(&val, 4040, __ATOMIC_RELEASE);
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if (__atomic_load_n(&val, __ATOMIC_ACQUIRE) != 4040)
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return 1;
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expected_ptr = &val;
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new_ptr = &tmp;
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if (!__atomic_compare_exchange_n(&ptr, &expected_ptr, new_ptr, 0,
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__ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST))
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return 1;
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__atomic_thread_fence(__ATOMIC_SEQ_CST);
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if (ptr != &tmp)
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return 1;
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return 0;
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}], [ap_cv_atomic_builtins_64=yes], [ap_cv_atomic_builtins_64=no], [ap_cv_atomic_builtins_64=no])])
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if test "$ap_cv_atomic_builtins_64" = "yes"; then
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AC_DEFINE(HAVE_ATOMIC_BUILTINS64, 1, [Define if compiler provides 64 bit atomic builtins])
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fi
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])
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