Re: [PATCH v7 13/14] perf callchain: Support x86 target platform

[Jiri Olsa]

On Tue, May 31, 2016 at 11:19:11AM +0000, He Kuang wrote:

SNIP

> diff --git a/tools/perf/util/unwind-libunwind.c b/tools/perf/util/unwind-libunwind.c
> index e183390..5774317 100644
> --- a/tools/perf/util/unwind-libunwind.c
> +++ b/tools/perf/util/unwind-libunwind.c
> @@ -5,6 +5,7 @@
>  #include "arch/common.h"
>  
>  struct unwind_libunwind_ops __weak *local_unwind_libunwind_ops;
> +struct unwind_libunwind_ops __weak *x86_32_unwind_libunwind_ops;
>  
>  void unwind__register_ops(struct thread *thread,
>  			  struct unwind_libunwind_ops *ops)
> @@ -30,7 +31,13 @@ int unwind__prepare_access(struct thread *thread, struct map *map)
>  			 dso_type == DSO__TYPE_64BIT, map->dso->name);
>  
>  	arch = normalize_arch(thread->mg->machine->env->arch);
> -	pr_debug("unwind: target platform=%s\n", arch);
> +
> +	if (!strcmp(arch, "x86"))
> +		if (dso_type != DSO__TYPE_64BIT)
> +			ops = x86_32_unwind_libunwind_ops;
> +
> +	if (!ops)
> +		pr_err("unwind: target platform=%s is not supported\n", arch);

how could ops become NULL in here? it starts with local_unwind_libunwind_ops
I dont think this check is needed in here

jirka