Re: [PATCH v2 5/7] aarch64, arm: Remove accepted_branch_protection_string

[Richard Sandiford]

Szabolcs Nagy <szabolcs.n...@arm.com> writes:
> On aarch64 this caused ICE with pragma push_options since
>
>   commit ae54c1b09963779c5c3914782324ff48af32e2f1
>   Author:     Wilco Dijkstra <wilco.dijks...@arm.com>
>   CommitDate: 2022-06-01 18:13:57 +0100
>
>   AArch64: Cleanup option processing code
>
> The failure is at pop_options:
>
> internal compiler error: ‘global_options’ are modified in local context
>
> On arm the variable was unused.
>
> gcc/ChangeLog:
>
>       * config/aarch64/aarch64.cc (aarch64_override_options_after_change_1):
>       Do not override branch_protection options.
>       (aarch64_override_options): Remove accepted_branch_protection_string.
>       * config/arm/aarch-common.cc (BRANCH_PROTECT_STR_MAX): Remove.
>       (aarch_parse_branch_protection): Remove
>       accepted_branch_protection_string.
>       * config/arm/arm.cc: Likewise.

OK.  Not sure I fully understand the subtlety of how things worked
before Wilco's patch, but I agree it looks like all the results of
the parsing are correctly captured by Target options or TargetVariables
in aarch64.opt, and so no special handling is needed.

Thanks,
Richard

> ---
> unchanged from v1
> ---
>  gcc/config/aarch64/aarch64.cc  | 10 +---------
>  gcc/config/arm/aarch-common.cc | 16 ----------------
>  gcc/config/arm/arm.cc          |  2 --
>  3 files changed, 1 insertion(+), 27 deletions(-)
>
> diff --git a/gcc/config/aarch64/aarch64.cc b/gcc/config/aarch64/aarch64.cc
> index 88594bed8ce..f8e8fefc8d8 100644
> --- a/gcc/config/aarch64/aarch64.cc
> +++ b/gcc/config/aarch64/aarch64.cc
> @@ -323,8 +323,6 @@ bool aarch64_pcrelative_literal_loads;
>  /* Global flag for whether frame pointer is enabled.  */
>  bool aarch64_use_frame_pointer;
>  
> -char *accepted_branch_protection_string = NULL;
> -
>  /* Support for command line parsing of boolean flags in the tuning
>     structures.  */
>  struct aarch64_flag_desc
> @@ -18101,12 +18099,6 @@ aarch64_adjust_generic_arch_tuning (struct 
> tune_params &current_tune)
>  static void
>  aarch64_override_options_after_change_1 (struct gcc_options *opts)
>  {
> -  if (accepted_branch_protection_string)
> -    {
> -      opts->x_aarch64_branch_protection_string
> -     = xstrdup (accepted_branch_protection_string);
> -    }
> -
>    /* PR 70044: We have to be careful about being called multiple times for 
> the
>       same function.  This means all changes should be repeatable.  */
>  
> @@ -18715,7 +18707,7 @@ aarch64_override_options (void)
>    /* Return address signing is currently not supported for ILP32 targets.  
> For
>       LP64 targets use the configured option in the absence of a command-line
>       option for -mbranch-protection.  */
> -  if (!TARGET_ILP32 && accepted_branch_protection_string == NULL)
> +  if (!TARGET_ILP32 && aarch64_branch_protection_string == NULL)
>      {
>  #ifdef TARGET_ENABLE_PAC_RET
>        aarch_ra_sign_scope = AARCH_FUNCTION_NON_LEAF;
> diff --git a/gcc/config/arm/aarch-common.cc b/gcc/config/arm/aarch-common.cc
> index 5b96ff4c2e8..cbc7f68a8bf 100644
> --- a/gcc/config/arm/aarch-common.cc
> +++ b/gcc/config/arm/aarch-common.cc
> @@ -659,9 +659,6 @@ arm_md_asm_adjust (vec<rtx> &outputs, vec<rtx> & 
> /*inputs*/,
>    return saw_asm_flag ? seq : NULL;
>  }
>  
> -#define BRANCH_PROTECT_STR_MAX 255
> -extern char *accepted_branch_protection_string;
> -
>  static enum aarch_parse_opt_result
>  aarch_handle_no_branch_protection (char* str, char* rest)
>  {
> @@ -812,19 +809,6 @@ aarch_parse_branch_protection (const char *const_str, 
> char** last_str)
>        else
>       *last_str = NULL;
>      }
> -
> -  if (res == AARCH_PARSE_OK)
> -    {
> -      /* If needed, alloc the accepted string then copy in const_str.
> -     Used by override_option_after_change_1.  */
> -      if (!accepted_branch_protection_string)
> -     accepted_branch_protection_string
> -       = (char *) xmalloc (BRANCH_PROTECT_STR_MAX + 1);
> -      strncpy (accepted_branch_protection_string, const_str,
> -            BRANCH_PROTECT_STR_MAX + 1);
> -      /* Forcibly null-terminate.  */
> -      accepted_branch_protection_string[BRANCH_PROTECT_STR_MAX] = '\0';
> -    }
>    return res;
>  }
>  
> diff --git a/gcc/config/arm/arm.cc b/gcc/config/arm/arm.cc
> index 6e933c80183..f49312cace0 100644
> --- a/gcc/config/arm/arm.cc
> +++ b/gcc/config/arm/arm.cc
> @@ -2424,8 +2424,6 @@ const struct tune_params arm_fa726te_tune =
>    tune_params::SCHED_AUTOPREF_OFF
>  };
>  
> -char *accepted_branch_protection_string = NULL;
> -
>  /* Auto-generated CPU, FPU and architecture tables.  */
>  #include "arm-cpu-data.h"