[PATCH] x86_64: Build modf for libc and libm (BZ 33165)

H.J. Lu hjl.tools@gmail.com
Thu Jul 17 22:18:37 GMT 2025 

On Thu, Jul 17, 2025 at 12:27 PM Adhemerval Zanella
<adhemerval.zanella@linaro.org> wrote:
>
> The routines that are shared between libc and libm should use different
> rules to avoid using the same MODULE_NAME, to avoid potential issues
> like BZ#33165 where __stack_chk_fail not being routed to the internal
> symbol.
>
> Checked with a build for x86_64-linux-gnu, x86_64-linux-gnu-v2,
> x86_64-linux-gnu-v3, and x86_64-linux-gnu-v4 and -fstack-protector=all.
> ---
>  sysdeps/x86_64/fpu/multiarch/Makefile         | 39 +++++++------------
>  sysdeps/x86_64/fpu/multiarch/s_modf-avx.c     |  6 ++-
>  sysdeps/x86_64/fpu/multiarch/s_modf-sse4_1.c  |  5 +--
>  sysdeps/x86_64/fpu/multiarch/s_modf.c         |  2 +
>  sysdeps/x86_64/fpu/multiarch/s_modff-avx.c    |  6 ++-
>  sysdeps/x86_64/fpu/multiarch/s_modff-sse4_1.c |  4 +-
>  sysdeps/x86_64/fpu/multiarch/s_modff.c        |  2 +
>  7 files changed, 33 insertions(+), 31 deletions(-)
>
> diff --git a/sysdeps/x86_64/fpu/multiarch/Makefile b/sysdeps/x86_64/fpu/multiarch/Makefile
> index 81a870d3b1..289d3f6e0d 100644
> --- a/sysdeps/x86_64/fpu/multiarch/Makefile
> +++ b/sysdeps/x86_64/fpu/multiarch/Makefile
> @@ -27,18 +27,17 @@ CFLAGS-s_cosf-fma.c = -mfma -mavx2
>  CFLAGS-s_sincosf-fma.c = -mfma -mavx2
>
>  # Check if ISA level is 3 or above.
> -ifneq (,$(filter $(have-x86-isa-level),$(x86-isa-level-3-or-above)))
> -sysdep_routines += \
> +sysdep_calls += \
>    s_modf-avx \
>    s_modff-avx \
> -# sysdep_routines
> +# sysdep_calls
> +ifneq (,$(filter $(have-x86-isa-level),$(x86-isa-level-3-or-above)))
> +sysdep_routines += $(sysdep_calls)
>  libm-sysdep_routines += \
>    s_ceil-avx \
>    s_ceilf-avx \
>    s_floor-avx \
>    s_floorf-avx \
> -  s_modf-avx \
> -  s_modff-avx \
>    s_nearbyint-avx \
>    s_nearbyintf-avx \
>    s_rint-avx \
> @@ -62,10 +61,10 @@ libm-sysdep_routines += \
>    s_tan-fma4 \
>  # libm-sysdep_routines
>  endif
> -sysdep_routines += \
> +sysdep_calls += \
>    s_modf-sse4_1 \
>    s_modff-sse4_1 \
> -# sysdep_routines
> +# sysdep_calls
>  libm-sysdep_routines += \
>    e_asin-fma \
>    e_atan2-avx \
> @@ -95,8 +94,6 @@ libm-sysdep_routines += \
>    s_floor-sse4_1 \
>    s_floorf-sse4_1 \
>    s_log1p-fma \
> -  s_modf-sse4_1 \
> -  s_modff-sse4_1 \
>    s_nearbyint-sse4_1 \
>    s_nearbyintf-sse4_1 \
>    s_rint-sse4_1 \
> @@ -118,17 +115,15 @@ libm-sysdep_routines += \
>    s_truncf-sse4_1 \
>  # libm-sysdep_routines
>  ifeq ($(have-x86-isa-level),baseline)
> -sysdep_routines += \
> +sysdep_calls += \
>    s_modf-c \
>    s_modff-c \
> -# sysdep-routines
> +# sysdep-calls
>  libm-sysdep_routines += \
>    s_ceil-c \
>    s_ceilf-c \
>    s_floor-c \
>    s_floorf-c \
> -  s_modf-c \
> -  s_modff-c \
>    s_nearbyint-c \
>    s_nearbyintf-c \
>    s_rint-c \
> @@ -139,6 +134,9 @@ libm-sysdep_routines += \
>    s_truncf-c \
>  # libm-sysdep_routines
>  endif
> +
> +sysdep_routines += $(sysdep_calls)
> +libm-sysdep_routines += $(sysdep_calls:s_%=m_%)
>  endif
>
>  CFLAGS-e_asin-fma4.c = -mfma4
> @@ -159,18 +157,11 @@ CFLAGS-s_sin-avx.c = -msse2avx -DSSE2AVX
>  CFLAGS-s_tan-avx.c = -msse2avx -DSSE2AVX
>  CFLAGS-s_sincos-avx.c = -msse2avx -DSSE2AVX
>
> -CFLAGS-s_modf-c.c = $(no-stack-protector)
> -CFLAGS-s_modff-c.c = $(no-stack-protector)
> +CFLAGS-s_modf-sse4_1.c = -msse4.1 -fno-builtin-modff32x -fno-builtin-modff64
> +CFLAGS-s_modff-sse4_1.c = -msse4.1 -fno-builtin-modff32
>
> -CFLAGS-s_modf-sse4_1.c = -msse4.1 -fno-builtin-modff32x \
> -                        -fno-builtin-modff64 $(no-stack-protector)
> -CFLAGS-s_modff-sse4_1.c = -msse4.1 -fno-builtin-modff32 \
> -                         $(no-stack-protector)
> -
> -CFLAGS-s_modf-avx.c = -msse2avx -DSSE2AVX -fno-builtin-modff32x \
> -                     $(no-stack-protector) -fno-builtin-modff64
> -CFLAGS-s_modff-avx.c = -msse2avx -DSSE2AVX -fno-builtin-modff32 \
> -                     $(no-stack-protector)
> +CFLAGS-s_modf-avx.c = -msse2avx -DSSE2AVX -fno-builtin-modff32x -fno-builtin-modff64
> +CFLAGS-s_modff-avx.c = -msse2avx -DSSE2AVX -fno-builtin-modff32
>  endif
>
>  ifeq ($(subdir),mathvec)
> diff --git a/sysdeps/x86_64/fpu/multiarch/s_modf-avx.c b/sysdeps/x86_64/fpu/multiarch/s_modf-avx.c
> index db32398b4a..7bae3a5f79 100644
> --- a/sysdeps/x86_64/fpu/multiarch/s_modf-avx.c
> +++ b/sysdeps/x86_64/fpu/multiarch/s_modf-avx.c
> @@ -1 +1,5 @@
> -#include <sysdeps/ieee754/dbl-64/s_modf.c>
> +#include <sysdeps/x86/isa-level.h>
> +#if MINIMUM_X86_ISA_LEVEL < SSE4_1_X86_ISA_LEVEL
> +# define __modf __modf_avx
> +# include <sysdeps/ieee754/dbl-64/s_modf.c>
> +#endif
> diff --git a/sysdeps/x86_64/fpu/multiarch/s_modf-sse4_1.c b/sysdeps/x86_64/fpu/multiarch/s_modf-sse4_1.c
> index 6ef4c19a7e..8b9ed789d0 100644
> --- a/sysdeps/x86_64/fpu/multiarch/s_modf-sse4_1.c
> +++ b/sysdeps/x86_64/fpu/multiarch/s_modf-sse4_1.c
> @@ -1,7 +1,6 @@
>  #include <sysdeps/x86/isa-level.h>
>
> -#if MINIMUM_X86_ISA_LEVEL != SSE4_1_X86_ISA_LEVEL
> +#if MINIMUM_X86_ISA_LEVEL < SSE4_1_X86_ISA_LEVEL
>  # define __modf __modf_sse41
> +# include <sysdeps/ieee754/dbl-64/s_modf.c>
>  #endif
> -
> -#include <sysdeps/ieee754/dbl-64/s_modf.c>
> diff --git a/sysdeps/x86_64/fpu/multiarch/s_modf.c b/sysdeps/x86_64/fpu/multiarch/s_modf.c
> index d65977d69a..37df8b1c9f 100644
> --- a/sysdeps/x86_64/fpu/multiarch/s_modf.c
> +++ b/sysdeps/x86_64/fpu/multiarch/s_modf.c
> @@ -32,4 +32,6 @@
>
>  libc_ifunc_redirected (__redirect_modf, __modf, IFUNC_SELECTOR ());
>  libm_alias_double (__modf, modf)
> +#else
> +# include <sysdeps/ieee754/dbl-64/s_modf.c>
>  #endif
> diff --git a/sysdeps/x86_64/fpu/multiarch/s_modff-avx.c b/sysdeps/x86_64/fpu/multiarch/s_modff-avx.c
> index 804b0426b7..6dd5652273 100644
> --- a/sysdeps/x86_64/fpu/multiarch/s_modff-avx.c
> +++ b/sysdeps/x86_64/fpu/multiarch/s_modff-avx.c
> @@ -1 +1,5 @@
> -#include <sysdeps/ieee754/flt-32/s_modff.c>
> +#include <sysdeps/x86/isa-level.h>
> +#if MINIMUM_X86_ISA_LEVEL < SSE4_1_X86_ISA_LEVEL
> +# define __modff __modff_avx
> +# include <sysdeps/ieee754/flt-32/s_modff.c>
> +#endif
> diff --git a/sysdeps/x86_64/fpu/multiarch/s_modff-sse4_1.c b/sysdeps/x86_64/fpu/multiarch/s_modff-sse4_1.c
> index 0437e044f3..6ae80a1d66 100644
> --- a/sysdeps/x86_64/fpu/multiarch/s_modff-sse4_1.c
> +++ b/sysdeps/x86_64/fpu/multiarch/s_modff-sse4_1.c
> @@ -1,7 +1,7 @@
>  #include <sysdeps/x86/isa-level.h>
>
> -#if MINIMUM_X86_ISA_LEVEL != SSE4_1_X86_ISA_LEVEL
> +#if MINIMUM_X86_ISA_LEVEL < SSE4_1_X86_ISA_LEVEL
>  # define __modff __modff_sse41
> +# include <sysdeps/ieee754/flt-32/s_modff.c>
>  #endif
>
> -#include <sysdeps/ieee754/flt-32/s_modff.c>
> diff --git a/sysdeps/x86_64/fpu/multiarch/s_modff.c b/sysdeps/x86_64/fpu/multiarch/s_modff.c
> index 89d0a32c23..0d98606d7c 100644
> --- a/sysdeps/x86_64/fpu/multiarch/s_modff.c
> +++ b/sysdeps/x86_64/fpu/multiarch/s_modff.c
> @@ -32,4 +32,6 @@
>
>  libc_ifunc_redirected (__redirect_modff, __modff, IFUNC_SELECTOR ());
>  libm_alias_float (__modf, modf)
> +#else
> +# include <sysdeps/ieee754/flt-32/s_modff.c>
>  #endif
> --
> 2.43.0
>

We need to fix:

https://sourceware.org/bugzilla/show_bug.cgi?id=33173

first.

-- 
H.J.

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