On Tue, Oct 15, 2024 at 02:18:43PM +0800, Yangyu Chen wrote:
> Some architectures may use ',' in the attribute string, but it is not
> used as the separator for different targets. To avoid conflict, we
> introduce a new macro TARGET_FMV_ATTR_SEPARATOR to separate different
> clones.

This is only for the target_clones attribute, so how about calling it
TARGET_CLONES_ATTR_SEPARATOR instead (or pluralised - see below)?

> As an example, according to RISC-V C-API Specification [1], RISC-V allows
> ',' in the attribute string in the "arch=" option to specify one more
> ISA extensions in the same target function, which conflict with the
> default separator to separate different clones. This patch introduces
> TARGET_FMV_ATTR_SEPARATOR for RISC-V and choose '#' as the separator,
> since '#' is not allowed in the target_clones option string.
> 
> [1] 
> https://github.com/riscv-non-isa/riscv-c-api-doc/blob/c6c5d6d9cf96b342293315a5dff3d25e96ef8191/src/c-api.adoc#__attribute__targetattr-string
> 
> gcc/ChangeLog:
> 
>         * defaults.h (TARGET_FMV_ATTR_SEPARATOR): Define new macro.
>         * multiple_target.cc (get_attr_str): Use
>           TARGET_FMV_ATTR_SEPARATOR to separate attributes.
>         (separate_attrs): Likewise.
>         * config/riscv/riscv.h (TARGET_FMV_ATTR_SEPARATOR): Define
>           TARGET_FMV_ATTR_SEPARATOR for RISC-V.
> ---
>  gcc/config/riscv/riscv.h |  5 +++++
>  gcc/defaults.h           |  4 ++++
>  gcc/multiple_target.cc   | 19 ++++++++++++-------
>  3 files changed, 21 insertions(+), 7 deletions(-)
> 
> diff --git a/gcc/config/riscv/riscv.h b/gcc/config/riscv/riscv.h
> index ca1b8329cdc..858cab72a4c 100644
> --- a/gcc/config/riscv/riscv.h
> +++ b/gcc/config/riscv/riscv.h
> @@ -1298,4 +1298,9 @@ extern void riscv_remove_unneeded_save_restore_calls 
> (void);
>               STACK_BOUNDARY / BITS_PER_UNIT)            \
>      : (crtl->outgoing_args_size + STACK_POINTER_OFFSET))
>  
> +/* According to the RISC-V C API, the arch string may contains ','. To avoid
> +   the conflict with the default separator, we choose '#' as the separator 
> for
> +   the target attribute.  */
> +#define TARGET_FMV_ATTR_SEPARATOR '#'
> +
>  #endif /* ! GCC_RISCV_H */
> diff --git a/gcc/defaults.h b/gcc/defaults.h
> index ac2d25852ab..f451efcb33e 100644
> --- a/gcc/defaults.h
> +++ b/gcc/defaults.h
> @@ -874,6 +874,10 @@ see the files COPYING3 and COPYING.RUNTIME respectively. 
>  If not, see
>  #define TARGET_HAS_FMV_TARGET_ATTRIBUTE 1
>  #endif
>  
> +/* Select a attribute separator for function multiversioning.  */
> +#ifndef TARGET_FMV_ATTR_SEPARATOR
> +#define TARGET_FMV_ATTR_SEPARATOR ','
> +#endif
>  
>  /* Select a format to encode pointers in exception handling data.  We
>     prefer those that result in fewer dynamic relocations.  Assume no
> diff --git a/gcc/multiple_target.cc b/gcc/multiple_target.cc
> index 1fdd279da04..5a056b44571 100644
> --- a/gcc/multiple_target.cc
> +++ b/gcc/multiple_target.cc
> @@ -180,7 +180,7 @@ create_dispatcher_calls (struct cgraph_node *node)
>      }
>  }
>  
> -/* Create string with attributes separated by comma.
> +/* Create string with attributes separated by TARGET_FMV_ATTR_SEPARATOR.
>     Return number of attributes.  */
>  
>  static int
> @@ -194,17 +194,21 @@ get_attr_str (tree arglist, char *attr_str)
>      {
>        const char *str = TREE_STRING_POINTER (TREE_VALUE (arg));
>        size_t len = strlen (str);
> -      for (const char *p = strchr (str, ','); p; p = strchr (p + 1, ','))
> +      for (const char *p = strchr (str, TARGET_FMV_ATTR_SEPARATOR);
> +        p;
> +        p = strchr (p + 1, TARGET_FMV_ATTR_SEPARATOR))
>       argnum++;
>        memcpy (attr_str + str_len_sum, str, len);
> -      attr_str[str_len_sum + len] = TREE_CHAIN (arg) ? ',' : '\0';
> +      attr_str[str_len_sum + len]
> +     = TREE_CHAIN (arg) ? TARGET_FMV_ATTR_SEPARATOR : '\0';
>        str_len_sum += len + 1;
>        argnum++;
>      }
>    return argnum;
>  }
>  
> -/* Return number of attributes separated by comma and put them into ARGS.
> +/* Return number of attributes separated by TARGET_FMV_ATTR_SEPARATOR and put
> +   them into ARGS.
>     If there is no DEFAULT attribute return -1.
>     If there is an empty string in attribute return -2.
>     If there are multiple DEFAULT attributes return -3.
> @@ -215,9 +219,10 @@ separate_attrs (char *attr_str, char **attrs, int 
> attrnum)
>  {
>    int i = 0;
>    int default_count = 0;
> +  char separator_str[] = {TARGET_FMV_ATTR_SEPARATOR, '\0'};

How about defining the macro as a string (and appending an S to the name - e.g.
TARGET_CLONES_ATTR_SEPARATORS)?
 
> -  for (char *attr = strtok (attr_str, ",");
> -       attr != NULL; attr = strtok (NULL, ","))
> +  for (char *attr = strtok (attr_str, separator_str);
> +       attr != NULL; attr = strtok (NULL, separator_str))
>      {
>        if (strcmp (attr, "default") == 0)
>       {
> @@ -305,7 +310,7 @@ static bool
>  expand_target_clones (struct cgraph_node *node, bool definition)
>  {
>    int i;
> -  /* Parsing target attributes separated by comma.  */
> +  /* Parsing target attributes separated by TARGET_FMV_ATTR_SEPARATOR.  */
>    tree attr_target = lookup_attribute ("target_clones",
>                                      DECL_ATTRIBUTES (node->decl));
>    /* No targets specified.  */
> -- 
> 2.45.2
> 

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