diff options
| 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 | 46b738ffc2bf27c1c0bf0492f8c646c4496819dc (patch) | |
| tree | bfad592f5d0452c7554f4931936c904ca667c3de /src/backend/tcop/postgres.c | |
| parent | 0dc0284ade4ade315982d1300cb87006b42e72c3 (diff) | |
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 7bc03ae4edc..3abcbb538f7 100644 --- a/src/backend/tcop/postgres.c +++ b/src/backend/tcop/postgres.c @@ -3280,7 +3280,9 @@ 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) @@ -3290,8 +3292,16 @@ 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 |