With -O2 -D_FORTIFY_SOURCE=2 -mabi=ieeelongdouble -std=c11 (or some other -std=c* mode), the following testcase fails on powerpc64le-linux: #include <stdio.h> #include <stdarg.h> static char buf[4096]; static char gfmt[] = "%Lg"; static int __attribute__ ((noinline)) foo (char *str, const char *fmt, ...) { int ret; va_list ap; va_start (ap, fmt); ret = vsnprintf (str, 4096, fmt, ap); va_end (ap); return ret; } int main () { long double dval = 128; int ret = foo (buf, gfmt, dval); if (ret != 3 || __builtin_strcmp (buf, "128") != 0) __builtin_abort (); return 0; } It works without -D_FORTIFY_SOURCE*, or with the GNU standard modes (-std=gnu99 etc.). Preprocessed and reduced it is: extern int vsnprintf (char *__restrict __s, size_t __maxlen, const char *__restrict __format, __builtin_va_list __arg) __attribute__ ((__nothrow__)) __attribute__ ((__format__ (__printf__, 3, 0))); extern int __vsnprintf_chk (char *__restrict __s, size_t __n, int __flag, size_t __slen, const char *__restrict __format, __builtin_va_list __ap) __attribute__ ((__nothrow__ , __leaf__)); extern __inline __attribute__ ((__always_inline__)) __attribute__ ((__gnu_inline__)) __attribute__ ((__artificial__)) int __attribute__ ((__nothrow__ , __leaf__)) vsnprintf (char *__restrict __s, size_t __n, const char *__restrict __fmt, __builtin_va_list __ap) { return __builtin___vsnprintf_chk (__s, __n, 2 - 1, __builtin_object_size (__s, 2 > 1), __fmt, __ap); } extern __typeof (vsnprintf) vsnprintf __asm ("__vsnprintfieee128"); extern __typeof (__vsnprintf_chk) __vsnprintf_chk __asm ("__vsnprintf_chkieee128"); static char buf[4096]; static char gfmt[] = "%Lg"; static int __attribute__ ((noinline)) foo (char *str, const char *fmt, ...) { int ret; __builtin_va_list ap; __builtin_va_start (ap, fmt); ret = vsnprintf (str, 4096, fmt, ap); __builtin_va_end (ap); return ret; } int main () { long double dval = 128; int ret = foo (buf, gfmt, dval); if (ret != 3 || __builtin_strcmp (buf, "128") != 0) __builtin_abort (); return 0; }
Seems for non-_FORTIFY_SOURCE rs6000.cc deals with this in: size_t printf_len = strlen ("printf"); size_t scanf_len = strlen ("scanf"); if (len >= printf_len && strcmp (name + len - printf_len, "printf") == 0) newname = xasprintf ("__%sieee128", name); else if (len >= scanf_len && strcmp (name + len - scanf_len, "scanf") == 0) newname = xasprintf ("__isoc99_%sieee128", name); but we need to deal also with printf_chk.
Created attachment 52348 [details] gcc12-pr104380.patch Untested fix.
The master branch has been updated by Jakub Jelinek <jakub@gcc.gnu.org>: https://gcc.gnu.org/g:8d6fffc4bcd4afa0beb0efad4f3b95394aa15618 commit r12-7059-g8d6fffc4bcd4afa0beb0efad4f3b95394aa15618 Author: Jakub Jelinek <jakub@redhat.com> Date: Fri Feb 4 18:30:59 2022 +0100 rs6000: Fix up -D_FORTIFY_SOURCE* with -mabi=ieeelongdouble [PR104380] The following testcase FAILs when configured with --with-long-double-format=ieee . Only happens in the -std=c* modes, not the GNU modes; while the glibc headers have __asm redirects of vsnprintf and __vsnprinf_chk to __vsnprintfieee128 and __vsnprintf_chkieee128, the vsnprintf fortification extern inline gnu_inline always_inline wrapper calls __builtin_vsnprintf_chk and we actually emit a call to __vsnprinf_chk (i.e. with IBM extended long double) instead of __vsnprintf_chkieee128. rs6000_mangle_decl_assembler_name already had cases for *printf and *scanf, so this just adds another case for *printf_chk. *scanf_chk doesn't exist. __ prefixing isn't done because *printf_chk already starts with __. 2022-02-04 Jakub Jelinek <jakub@redhat.com> PR target/104380 * config/rs6000/rs6000.cc (rs6000_mangle_decl_assembler_name): Also adjust mangling of __builtin*printf_chk. * gcc.dg/pr104380.c: New test.
Fixed.
The master branch has been updated by Jakub Jelinek <jakub@gcc.gnu.org>: https://gcc.gnu.org/g:5d2a330dee37ed10daa424d33ab1bcd5727c187b commit r12-7084-g5d2a330dee37ed10daa424d33ab1bcd5727c187b Author: Jakub Jelinek <jakub@redhat.com> Date: Mon Feb 7 17:39:11 2022 +0100 testsuite: Fix up testsuite/gcc.c-torture/execute/builtins/lib/chk.c for powerpc [PR104380] > > The following testcase FAILs when configured with > > --with-long-double-format=ieee . Only happens in the -std=c* modes, not the > > GNU modes; while the glibc headers have __asm redirects of > > vsnprintf and __vsnprinf_chk to __vsnprintfieee128 and > > __vsnprintf_chkieee128, the vsnprintf fortification extern inline gnu_inline > > always_inline wrapper calls __builtin_vsnprintf_chk and we actually emit > > a call to __vsnprinf_chk (i.e. with IBM extended long double) instead of > > __vsnprintf_chkieee128. > > > > rs6000_mangle_decl_assembler_name already had cases for *printf and *scanf, > > so this just adds another case for *printf_chk. *scanf_chk doesn't exist. > > __ prefixing isn't done because *printf_chk already starts with __. Unfortunately, while I've tested the testcase also with -mabi=ieeelongdouble by hand, the full bootstrap/regtest was on GCCFarm where glibc is too old to test with --with-long-double-format=ieee. I've done full bootstrap/regtest with that option during the weekend and the patch regressed: FAIL: gcc.c-torture/execute/builtins/snprintf-chk.c execution, -O1 FAIL: gcc.c-torture/execute/builtins/snprintf-chk.c execution, -O2 FAIL: gcc.c-torture/execute/builtins/snprintf-chk.c execution, -O2 -flto -fno-use-linker-plugin -flto-partition=none FAIL: gcc.c-torture/execute/builtins/snprintf-chk.c execution, -O2 -flto -fuse-linker-plugin -fno-fat-lto-objects FAIL: gcc.c-torture/execute/builtins/snprintf-chk.c execution, -O3 -fomit-frame-pointer -funroll-loops -fpeel-loops -ftracer -finline-functions FAIL: gcc.c-torture/execute/builtins/snprintf-chk.c execution, -O3 -g FAIL: gcc.c-torture/execute/builtins/snprintf-chk.c execution, -Og -g FAIL: gcc.c-torture/execute/builtins/snprintf-chk.c execution, -Os FAIL: gcc.c-torture/execute/builtins/sprintf-chk.c execution, -O1 FAIL: gcc.c-torture/execute/builtins/sprintf-chk.c execution, -O2 FAIL: gcc.c-torture/execute/builtins/sprintf-chk.c execution, -O2 -flto -fno-use-linker-plugin -flto-partition=none FAIL: gcc.c-torture/execute/builtins/sprintf-chk.c execution, -O2 -flto -fuse-linker-plugin -fno-fat-lto-objects FAIL: gcc.c-torture/execute/builtins/sprintf-chk.c execution, -O3 -fomit-frame-pointer -funroll-loops -fpeel-loops -ftracer -finline-functions FAIL: gcc.c-torture/execute/builtins/sprintf-chk.c execution, -O3 -g FAIL: gcc.c-torture/execute/builtins/sprintf-chk.c execution, -Og -g FAIL: gcc.c-torture/execute/builtins/sprintf-chk.c execution, -Os FAIL: gcc.c-torture/execute/builtins/vsnprintf-chk.c execution, -O1 FAIL: gcc.c-torture/execute/builtins/vsnprintf-chk.c execution, -O2 FAIL: gcc.c-torture/execute/builtins/vsnprintf-chk.c execution, -O2 -flto -fno-use-linker-plugin -flto-partition=none FAIL: gcc.c-torture/execute/builtins/vsnprintf-chk.c execution, -O2 -flto -fuse-linker-plugin -fno-fat-lto-objects FAIL: gcc.c-torture/execute/builtins/vsnprintf-chk.c execution, -O3 -fomit-frame-pointer -funroll-loops -fpeel-loops -ftracer -finline-functions FAIL: gcc.c-torture/execute/builtins/vsnprintf-chk.c execution, -O3 -g FAIL: gcc.c-torture/execute/builtins/vsnprintf-chk.c execution, -Og -g FAIL: gcc.c-torture/execute/builtins/vsnprintf-chk.c execution, -Os FAIL: gcc.c-torture/execute/builtins/vsprintf-chk.c execution, -O1 FAIL: gcc.c-torture/execute/builtins/vsprintf-chk.c execution, -O2 FAIL: gcc.c-torture/execute/builtins/vsprintf-chk.c execution, -O2 -flto -fno-use-linker-plugin -flto-partition=none FAIL: gcc.c-torture/execute/builtins/vsprintf-chk.c execution, -O2 -flto -fuse-linker-plugin -fno-fat-lto-objects FAIL: gcc.c-torture/execute/builtins/vsprintf-chk.c execution, -O3 -fomit-frame-pointer -funroll-loops -fpeel-loops -ftracer -finline-functions FAIL: gcc.c-torture/execute/builtins/vsprintf-chk.c execution, -O3 -g FAIL: gcc.c-torture/execute/builtins/vsprintf-chk.c execution, -Og -g FAIL: gcc.c-torture/execute/builtins/vsprintf-chk.c execution, -Os The problem is that the execute/builtins/ testsuite wants to override some of the library functions and with the change we (correctly) call __*printf_chkieee128 and so lib/chk.c is no longer called but the glibc APIs are. 2022-02-07 Jakub Jelinek <jakub@redhat.com> PR target/104380 * gcc.c-torture/execute/builtins/lib/chk.c (__sprintf_chkieee128, __vsprintf_chkieee128, __snprintf_chkieee128, __vsnprintf_chkieee128): New aliases to non-ieee128 suffixed functions for powerpc -mabi=ieeelongdouble.