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Re: [PATCH] gdb.trace: Fix string collection for 64-bit platforms.
- From: Pedro Alves <palves at redhat dot com>
- To: Marcin KoÅcielnicki <koriakin at 0x04 dot net>, gdb-patches at sourceware dot org
- Date: Thu, 21 Jan 2016 16:14:13 +0000
- Subject: Re: [PATCH] gdb.trace: Fix string collection for 64-bit platforms.
- Authentication-results: sourceware.org; auth=none
- References: <1453392126-2242-1-git-send-email-koriakin at 0x04 dot net>
On 01/21/2016 04:02 PM, Marcin KoÅcielnicki wrote:
> String collection always used ref32 to fetch the string pointer. Make it
> use ref64 when pointeer size is 64-bit.
"pointer".
>
> This appeared to work on x86_64 since it's a little-endian platform, and
> malloc (used in gdb.trace/collection.exp) returns addresses in low 4GB.
> Noticed and tested on s390x-ibm-linux-gnu, also tested on
> i686-unknown-linux-gnu and x86_64-unknown-linux-gnu.
>
> gdb/ChangeLog:
>
> * ax-gdb.c (gen_traced_pop): Use aop_ref64 when appropriate for
> string collection.
> ---
> OK to push?
>
> gdb/ChangeLog | 5 +++++
> gdb/ax-gdb.c | 5 ++++-
> 2 files changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/gdb/ChangeLog b/gdb/ChangeLog
> index 45d8ef9..3f4d152 100644
> --- a/gdb/ChangeLog
> +++ b/gdb/ChangeLog
> @@ -1,3 +1,8 @@
> +2016-01-21 Marcin KoÅcielnicki <koriakin@0x04.net>
> +
> + * ax-gdb.c (gen_traced_pop): Use aop_ref64 when appropriate for
> + string collection.
> +
> 2016-01-21 Andrew Burgess <andrew.burgess@embecosm.com>
>
> * disasm.c (maybe_add_dis_line_entry): Rename to...
> diff --git a/gdb/ax-gdb.c b/gdb/ax-gdb.c
> index dd6eee6..d17cb04 100644
> --- a/gdb/ax-gdb.c
> +++ b/gdb/ax-gdb.c
> @@ -410,7 +410,10 @@ gen_traced_pop (struct gdbarch *gdbarch,
>
> if (string_trace)
> {
> - ax_simple (ax, aop_ref32);
> + if (TYPE_LENGTH(value->type) == 4)
Missing space before parens.
> + ax_simple (ax, aop_ref32);
> + else
> + ax_simple (ax, aop_ref64);
> + if (TYPE_LENGTH(value->type) == 4)
> + ax_simple (ax, aop_ref32);
> + else
> + ax_simple (ax, aop_ref64);
Missing space before parens. I was going to say to
check for == 8 instead so that we don't pessimize the
8/16 bits cases, but sounds better even to factor out
the switch in gen_fetch, so that the ref8/ref16 are covered
as well:
switch (TYPE_LENGTH (type))
{
case 8 / TARGET_CHAR_BIT:
ax_simple (ax, aop_ref8);
break;
case 16 / TARGET_CHAR_BIT:
ax_simple (ax, aop_ref16);
break;
case 32 / TARGET_CHAR_BIT:
ax_simple (ax, aop_ref32);
break;
case 64 / TARGET_CHAR_BIT:
ax_simple (ax, aop_ref64);
break;
/* Either our caller shouldn't have asked us to dereference
that pointer (other code's fault), or we're not
implementing something we should be (this code's fault).
In any case, it's a bug the user shouldn't see. */
default:
internal_error (__FILE__, __LINE__,
WDYT?
Thanks,
Pedro Alves