On Fri, Jan 27, 2023 at 2:44 PM Andrea Corallo via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> gcc/
>
> * config/arm/arm.cc (arm_valid_target_attribute_rec): Add ARM function
> attribute 'branch-protection' and parse its options.
> * doc/extend.texi: Document ARM Function attribute
> 'branch-protection'.
Nit: s/ARM/arm or s/ARM/AArch32.
>
> gcc/testsuite/
>
> * gcc.target/arm/acle/pacbti-m-predef-13.c: New test.
>
> Co-Authored-By: Tejas Belagod <tbela...@arm.com>
> ---
> gcc/config/arm/arm.cc | 16 ++++++++
> gcc/doc/extend.texi | 7 ++++
> .../gcc.target/arm/acle/pacbti-m-predef-13.c | 41 +++++++++++++++++++
> 3 files changed, 64 insertions(+)
> create mode 100644 gcc/testsuite/gcc.target/arm/acle/pacbti-m-predef-13.c
>
> diff --git a/gcc/config/arm/arm.cc b/gcc/config/arm/arm.cc
> index efc48349dd3..add33090f18 100644
> --- a/gcc/config/arm/arm.cc
> +++ b/gcc/config/arm/arm.cc
> @@ -33568,6 +33568,22 @@ arm_valid_target_attribute_rec (tree args, struct
> gcc_options *opts)
>
> opts->x_arm_arch_string = xstrndup (arch, strlen (arch));
> }
> + else if (startswith (q, "branch-protection="))
> + {
> + char *bp_str = q + strlen ("branch-protection=");
> +
> + opts->x_arm_branch_protection_string
> + = xstrndup (bp_str, strlen (bp_str));
> +
> + /* Capture values from target attribute. */
> + aarch_validate_mbranch_protection
> + (opts->x_arm_branch_protection_string);
> +
> + /* Init function target attr values. */
> + opts->x_aarch_ra_sign_scope = aarch_ra_sign_scope;
> + opts->x_aarch_enable_bti = aarch_enable_bti;
> +
> + }
> else if (q[0] == '+')
> {
> opts->x_arm_arch_string
> diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi
> index 4a89a3eae7c..23ee43919dd 100644
> --- a/gcc/doc/extend.texi
> +++ b/gcc/doc/extend.texi
> @@ -4492,6 +4492,13 @@ Enable or disable calls to out-of-line helpers to
> implement atomic operations.
> This corresponds to the behavior of the command line options
> @option{-moutline-atomics} and @option{-mno-outline-atomics}.
>
> +@item branch-protection=
> +@cindex @code{branch-protection=} function attribute, arm
> +Select the function scope on which branch protection will be applied.
> +The behavior and permissible arguments are the same as for the
> +command-line option @option{-mbranch-protection=}. The default value
> +is @code{none}.
> +
> @end table
>
> The above target attributes can be specified as follows:
> diff --git a/gcc/testsuite/gcc.target/arm/acle/pacbti-m-predef-13.c
> b/gcc/testsuite/gcc.target/arm/acle/pacbti-m-predef-13.c
> new file mode 100644
> index 00000000000..b6d2df53072
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/arm/acle/pacbti-m-predef-13.c
> @@ -0,0 +1,41 @@
> +/* { dg-do compile } */
> +/* { dg-require-effective-target mbranch_protection_ok } */
> +/* { dg-options "-march=armv8.1-m.main+fp -mbranch-protection=pac-ret+leaf
> -mfloat-abi=hard --save-temps" } */
> +/* { dg-final { check-function-bodies "**" "" } } */
> +
> +#if defined (__ARM_FEATURE_BTI_DEFAULT)
> +#error "Feature test macro __ARM_FEATURE_BTI_DEFAULT should be undefined."
> +#endif
> +
> +#if !defined (__ARM_FEATURE_PAC_DEFAULT)
> +#error "Feature test macro __ARM_FEATURE_PAC_DEFAULT should be defined."
> +#endif
> +
> +/*
> +**foo:
> +** bti
> +** ...
> +*/
> +__attribute__((target("branch-protection=pac-ret+bti"), noinline))
> +int foo ()
> +{
> + return 3;
> +}
> +
> +/*
> +**main:
> +** pac ip, lr, sp
> +** ...
> +** aut ip, lr, sp
> +** bx lr
> +*/
> +int
> +main()
> +{
> + return 1 + foo ();
> +}
> +
> +/* { dg-final { scan-assembler "\.eabi_attribute 50, 1" } } */
> +/* { dg-final { scan-assembler "\.eabi_attribute 52, 1" } } */
> +/* { dg-final { scan-assembler-not "\.eabi_attribute 74" } } */
> +/* { dg-final { scan-assembler "\.eabi_attribute 76, 1" } } */
> --
> 2.25.1
>
If the attribute covers all the options that are in the command line
documentation, surely there need to be tests for
__attribute__((target("branch-protection=standard")) ?
regards
Ramana
