2024-05-07 04:13:47

by Namhyung Kim

[permalink] [raw]
Subject: [PATCH] perf dwarf-aux: Print array type name with "[]"

It's confusing both pointers and arrays are printed as *. Let's print
array types with [] so that we can identify them easily. Although it's
interchangable, sometimes it can cause confusion with size like in the
below example.

Note that it is not the same with C syntax where it goes to the variable
names, but we want to have it in the type names (like in Go language).

Before:
mov [20] 0x68(reg5) -> reg0 type='struct page**' size=0x80 (die:0x4e61d32)

After:
mov [20] 0x68(reg5) -> reg0 type='struct page*[]' size=0x80 (die:0x4e61d32)

Cc: Masami Hiramatsu <[email protected]>
Signed-off-by: Namhyung Kim <[email protected]>
---
tools/perf/util/dwarf-aux.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c
index c0a492e65388..ec988f294497 100644
--- a/tools/perf/util/dwarf-aux.c
+++ b/tools/perf/util/dwarf-aux.c
@@ -1110,8 +1110,10 @@ int die_get_typename_from_type(Dwarf_Die *type_die, struct strbuf *buf)
const char *tmp = "";

tag = dwarf_tag(type_die);
- if (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)
+ if (tag == DW_TAG_pointer_type)
tmp = "*";
+ else if (tag == DW_TAG_array_type)
+ tmp = "[]";
else if (tag == DW_TAG_subroutine_type) {
/* Function pointer */
return strbuf_add(buf, "(function_type)", 15);
--
2.45.0.rc1.225.g2a3ae87e7f-goog



2024-05-08 00:19:56

by Masami Hiramatsu

[permalink] [raw]
Subject: Re: [PATCH] perf dwarf-aux: Print array type name with "[]"

On Mon, 6 May 2024 21:13:38 -0700
Namhyung Kim <[email protected]> wrote:

> It's confusing both pointers and arrays are printed as *. Let's print
> array types with [] so that we can identify them easily. Although it's
> interchangable, sometimes it can cause confusion with size like in the
> below example.
>
> Note that it is not the same with C syntax where it goes to the variable
> names, but we want to have it in the type names (like in Go language).
>
> Before:
> mov [20] 0x68(reg5) -> reg0 type='struct page**' size=0x80 (die:0x4e61d32)
>
> After:
> mov [20] 0x68(reg5) -> reg0 type='struct page*[]' size=0x80 (die:0x4e61d32)
>

Good improvement!

Acked-by: Masami Hiramatsu (Google) <[email protected]>

Thank you!

> Cc: Masami Hiramatsu <[email protected]>
> Signed-off-by: Namhyung Kim <[email protected]>
> ---
> tools/perf/util/dwarf-aux.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c
> index c0a492e65388..ec988f294497 100644
> --- a/tools/perf/util/dwarf-aux.c
> +++ b/tools/perf/util/dwarf-aux.c
> @@ -1110,8 +1110,10 @@ int die_get_typename_from_type(Dwarf_Die *type_die, struct strbuf *buf)
> const char *tmp = "";
>
> tag = dwarf_tag(type_die);
> - if (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)
> + if (tag == DW_TAG_pointer_type)
> tmp = "*";
> + else if (tag == DW_TAG_array_type)
> + tmp = "[]";
> else if (tag == DW_TAG_subroutine_type) {
> /* Function pointer */
> return strbuf_add(buf, "(function_type)", 15);
> --
> 2.45.0.rc1.225.g2a3ae87e7f-goog
>


--
Masami Hiramatsu (Google) <[email protected]>

2024-05-08 00:42:17

by Arnaldo Carvalho de Melo

[permalink] [raw]
Subject: Re: [PATCH] perf dwarf-aux: Print array type name with "[]"

On Wed, May 08, 2024 at 08:57:51AM +0900, Masami Hiramatsu wrote:
> On Mon, 6 May 2024 21:13:38 -0700
> Namhyung Kim <[email protected]> wrote:
>
> > It's confusing both pointers and arrays are printed as *. Let's print
> > array types with [] so that we can identify them easily. Although it's
> > interchangable, sometimes it can cause confusion with size like in the
> > below example.
> >
> > Note that it is not the same with C syntax where it goes to the variable
> > names, but we want to have it in the type names (like in Go language).
> >
> > Before:
> > mov [20] 0x68(reg5) -> reg0 type='struct page**' size=0x80 (die:0x4e61d32)
> >
> > After:
> > mov [20] 0x68(reg5) -> reg0 type='struct page*[]' size=0x80 (die:0x4e61d32)
> >
>
> Good improvement!
>
> Acked-by: Masami Hiramatsu (Google) <[email protected]>

Indeed,

Thanks, applied to perf-tools-next,

- Arnaldo