Fix 32-bit build warnings with newer GCC on Ubuntu 25#14966
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vitahlin wants to merge 5 commits intoredis:unstablefrom
Open
Fix 32-bit build warnings with newer GCC on Ubuntu 25#14966vitahlin wants to merge 5 commits intoredis:unstablefrom
vitahlin wants to merge 5 commits intoredis:unstablefrom
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🤖 Augment PR SummarySummary: Fixes new GCC warnings seen on 32-bit Redis builds (Ubuntu 25 toolchain). Changes:
Technical Notes: The atomic alignment change impacts all 🤖 Was this summary useful? React with 👍 or 👎 |
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This PR fixes several compiler warnings triggered by the newer GCC toolchain (Ubuntu 25 default) when building Redis on 32-bit systems.
Changed
1. Define unreachable only when not provided by the toolchain
Recent GCC versions and C23 may provide
unreachableas a built-in; unconditional redefinition can cause conflicts or build failures.2. Enforce 8-byte alignment for C11 _Atomic on 32-bit builds
64-bit atomic types (long long, uint64_t, time_t) on 32-bit architectures require strict 8-byte alignment to remain truly atomic and avoid alignment warnings/faults. A new redisAtomicAlign(n) macro is introduced to apply attribute((aligned(n))) only on 32-bit platforms, while redisAtomic remains a plain _Atomic qualifier. This avoids unnecessary padding and struct layout changes for smaller types (int, uint32_t) and on 64-bit systems where the compiler already provides correct natural alignment.
3. Use uintptr_t for pointer–integer conversions in module tests
Direct pointer/integer casts are size-sensitive across 32/64-bit targets and trigger stricter portability warnings.
CI result: https://github.com/vitahlin/redis/actions/runs/23744054245/job/69283039740
Note
Medium Risk
Touches low-level portability primitives (jemalloc
unreachable, C11 atomics alignment, and pointer/integer conversions), which could impact 32-bit correctness if misapplied, but the changes are small and largely mechanical.Overview
Improves 32-bit build portability with newer GCC/C23 by avoiding conflicts with toolchain-provided
unreachable(only defines jemalloc’sunreachable()if not already defined).Adjusts the C11 atomic path to force 8-byte alignment for
redisAtomicvariables, and updates several test modules to cast metadata pointers and timer callbackdatathroughuintptr_tbefore storing in/reading fromuint64_torvoid*, eliminating size-related warnings.Written by Cursor Bugbot for commit 75e2475. This will update automatically on new commits. Configure here.