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If the executable's .o files were produced by a compiler (probably gcc) not using -moutline-atomics, and the corresponding .bc files were produced by clang using -moutline-atomics (probably by default), then the generated bitcode functions would have the target attribute "+outline-atomics", and could fail at runtime when inlined. If the target ISA at bitcode generation time was armv8-a (the most conservative aarch64 target, no LSE), then LLVM IR atomic instructions would generate calls to functions in libgcc.a or libclang_rt.*.a that switch between LL/SC and faster LSE instructions depending on a runtime AT_HWCAP check. Since the corresponding .o files didn't need those functions, they wouldn't have been included in the executable, and resolution would fail. At least Debian and Ubuntu are known to ship gcc and clang compilers that target armv8-a but differ on the use of outline atomics by default. Fix, by suppressing the outline atomics attribute in bitcode explicitly. Inline LL/SC instructions will be generated for atomic operations in bitcode built for armv8-a. Only configure scripts are adjusted for now, because the meson build system doesn't generate bitcode yet. This doesn't seem to be a new phenomenon, so real cases of functions using atomics that are inlined by JIT must be rare in the wild given how long it took for a bug report to arrive. The reported case could be reduced to: postgres=# set jit_inline_above_cost = 0; SET postgres=# set jit_above_cost = 0; SET postgres=# select pg_last_wal_receive_lsn(); WARNING: failed to resolve name __aarch64_swp4_acq_rel FATAL: fatal llvm error: Program used external function '__aarch64_swp4_acq_rel' which could not be resolved! The change doesn't affect non-ARM systems or later target ISAs. Back-patch to all supported releases. Reported-by: Alexander Kozhemyakin <a.kozhemyakin@postgrespro.ru> Discussion: https://postgr.es/m/18610-37bf303f904fede3%40postgresql.org
PostgreSQL Database Management System ===================================== This directory contains the source code distribution of the PostgreSQL database management system. PostgreSQL is an advanced object-relational database management system that supports an extended subset of the SQL standard, including transactions, foreign keys, subqueries, triggers, user-defined types and functions. This distribution also contains C language bindings. PostgreSQL has many language interfaces, many of which are listed here: https://www.postgresql.org/download/ See the file INSTALL for instructions on how to build and install PostgreSQL. That file also lists supported operating systems and hardware platforms and contains information regarding any other software packages that are required to build or run the PostgreSQL system. Copyright and license information can be found in the file COPYRIGHT. A comprehensive documentation set is included in this distribution; it can be read as described in the installation instructions. The latest version of this software may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.