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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2022-02-17 22:45:34 -0500 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2022-02-17 22:45:34 -0500 |
| commit | e0d4123bbcfe6d85eb3130ded4478f2135d116f2 (patch) | |
| tree | d0112c70a0cba5496dd005089d6bd13417aca9d2 /src/backend/tcop/postgres.c | |
| parent | af2d484e0e4676db1d90207402c16e5530f80a9c (diff) | |
| download | postgresql-e0d4123bbcfe6d85eb3130ded4478f2135d116f2.tar.gz postgresql-e0d4123bbcfe6d85eb3130ded4478f2135d116f2.zip | |
Suppress warning about stack_base_ptr with late-model GCC.
GCC 12 complains that set_stack_base is storing the address of
a local variable in a long-lived pointer. This is an entirely
reasonable warning (indeed, it just helped us find a bug);
but that behavior is intentional here. We can work around it
by using __builtin_frame_address(0) instead of a specific local
variable; that produces an address a dozen or so bytes different,
in my testing, but we don't care about such a small difference.
Maybe someday a compiler lacking that function will start to issue
a similar warning, but we'll worry about that when it happens.
Patch by me, per a suggestion from Andres Freund. Back-patch to
v12, which is as far back as the patch will go without some pain.
(Recently-established project policy would permit a back-patch as
far as 9.2, but I'm disinclined to expend the work until GCC 12
is much more widespread.)
Discussion: https://postgr.es/m/3773792.1645141467@sss.pgh.pa.us
Diffstat (limited to 'src/backend/tcop/postgres.c')
| -rw-r--r-- | src/backend/tcop/postgres.c | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c index 361866ad7fb..1928cdd3c05 100644 --- a/src/backend/tcop/postgres.c +++ b/src/backend/tcop/postgres.c @@ -3210,7 +3210,9 @@ ia64_get_bsp(void) pg_stack_base_t set_stack_base(void) { +#ifndef HAVE__BUILTIN_FRAME_ADDRESS char stack_base; +#endif pg_stack_base_t old; #if defined(__ia64__) || defined(__ia64) @@ -3220,8 +3222,16 @@ set_stack_base(void) old = stack_base_ptr; #endif - /* Set up reference point for stack depth checking */ + /* + * Set up reference point for stack depth checking. On recent gcc we use + * __builtin_frame_address() to avoid a warning about storing a local + * variable's address in a long-lived variable. + */ +#ifdef HAVE__BUILTIN_FRAME_ADDRESS + stack_base_ptr = __builtin_frame_address(0); +#else stack_base_ptr = &stack_base; +#endif #if defined(__ia64__) || defined(__ia64) register_stack_base_ptr = ia64_get_bsp(); #endif |