Re: [PATCH 2/2] gcov: re-drop support for clang-10

[Fangrui Song]

On 2021-04-07, Nick Desaulniers wrote:
> LLVM changed the expected function signatures for
> llvm_gcda_emit_function() in the clang-11 release.  Drop the older
> implementations and require folks to upgrade their compiler if they're
> interested in GCOV support.
>
> Signed-off-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
> ---
> kernel/gcov/clang.c | 40 ----------------------------------------
> 1 file changed, 40 deletions(-)
>
> diff --git a/kernel/gcov/clang.c b/kernel/gcov/clang.c
> index 1747204541bf..78c4dc751080 100644
> --- a/kernel/gcov/clang.c
> +++ b/kernel/gcov/clang.c
> @@ -69,9 +69,6 @@ struct gcov_fn_info {
>
> 	u32 ident;
> 	u32 checksum;
> -#if CONFIG_CLANG_VERSION < 110000
> -	u8 use_extra_checksum;
> -#endif
> 	u32 cfg_checksum;
>
> 	u32 num_counters;
> @@ -113,23 +110,6 @@ void llvm_gcda_start_file(const char *orig_filename, u32 version, u32 checksum)
> }
> EXPORT_SYMBOL(llvm_gcda_start_file);
>
> -#if CONFIG_CLANG_VERSION < 110000
> -void llvm_gcda_emit_function(u32 ident, u32 func_checksum,
> -		u8 use_extra_checksum, u32 cfg_checksum)
> -{
> -	struct gcov_fn_info *info = kzalloc(sizeof(*info), GFP_KERNEL);
> -
> -	if (!info)
> -		return;
> -
> -	INIT_LIST_HEAD(&info->head);
> -	info->ident = ident;
> -	info->checksum = func_checksum;
> -	info->use_extra_checksum = use_extra_checksum;
> -	info->cfg_checksum = cfg_checksum;
> -	list_add_tail(&info->head, &current_info->functions);
> -}
> -#else
> void llvm_gcda_emit_function(u32 ident, u32 func_checksum, u32 cfg_checksum)
> {
> 	struct gcov_fn_info *info = kzalloc(sizeof(*info), GFP_KERNEL);
> @@ -143,7 +123,6 @@ void llvm_gcda_emit_function(u32 ident, u32 func_checksum, u32 cfg_checksum)
> 	info->cfg_checksum = cfg_checksum;
> 	list_add_tail(&info->head, &current_info->functions);
> }
> -#endif
> EXPORT_SYMBOL(llvm_gcda_emit_function);
>
> void llvm_gcda_emit_arcs(u32 num_counters, u64 *counters)
> @@ -274,16 +253,8 @@ int gcov_info_is_compatible(struct gcov_info *info1, struct gcov_info *info2)
> 		!list_is_last(&fn_ptr2->head, &info2->functions)) {
> 		if (fn_ptr1->checksum != fn_ptr2->checksum)
> 			return false;
> -#if CONFIG_CLANG_VERSION < 110000
> -		if (fn_ptr1->use_extra_checksum != fn_ptr2->use_extra_checksum)
> -			return false;
> -		if (fn_ptr1->use_extra_checksum &&
> -			fn_ptr1->cfg_checksum != fn_ptr2->cfg_checksum)
> -			return false;
> -#else
> 		if (fn_ptr1->cfg_checksum != fn_ptr2->cfg_checksum)
> 			return false;
> -#endif
> 		fn_ptr1 = list_next_entry(fn_ptr1, head);
> 		fn_ptr2 = list_next_entry(fn_ptr2, head);
> 	}
> @@ -403,21 +374,10 @@ size_t convert_to_gcda(char *buffer, struct gcov_info *info)
> 		u32 i;
>
> 		pos += store_gcov_u32(buffer, pos, GCOV_TAG_FUNCTION);
> -#if CONFIG_CLANG_VERSION < 110000
> -		pos += store_gcov_u32(buffer, pos,
> -			fi_ptr->use_extra_checksum ? 3 : 2);
> -#else
> 		pos += store_gcov_u32(buffer, pos, 3);
> -#endif
> 		pos += store_gcov_u32(buffer, pos, fi_ptr->ident);
> 		pos += store_gcov_u32(buffer, pos, fi_ptr->checksum);
> -#if CONFIG_CLANG_VERSION < 110000
> -		if (fi_ptr->use_extra_checksum)
> -			pos += store_gcov_u32(buffer, pos, fi_ptr->cfg_checksum);
> -#else
> 		pos += store_gcov_u32(buffer, pos, fi_ptr->cfg_checksum);
> -#endif
> -
> 		pos += store_gcov_u32(buffer, pos, GCOV_TAG_COUNTER_BASE);
> 		pos += store_gcov_u32(buffer, pos, fi_ptr->num_counters * 2);
> 		for (i = 0; i < fi_ptr->num_counters; i++)
> --
> 2.31.1.295.g9ea45b61b8-goog

Looks good for both. Thanks!

Reviewed-by: Fangrui Song <maskray@xxxxxxxxxx>