From: Carlos O'Donell <carlos@redhat.com>
To: Florian Weimer <fweimer@redhat.com>, libc-alpha@sourceware.org
Subject: Re: [PATCH 04/10] i386: Implement backtrace on top of <unwind-link.h>
Date: Mon, 1 Mar 2021 08:54:40 -0500 [thread overview]
Message-ID: <e27b1c97-a2ec-caea-dcbc-13886011a6d8@redhat.com> (raw)
In-Reply-To: <c613ce9414628bd44742134c83dbf86d883cf5b3.1613577607.git.fweimer@redhat.com>
On 2/17/21 11:03 AM, Florian Weimer via Libc-alpha wrote:
LGTM. And the i386 version.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
> ---
> sysdeps/i386/backtrace.c | 82 +++++++++-------------------------------
> 1 file changed, 18 insertions(+), 64 deletions(-)
>
> diff --git a/sysdeps/i386/backtrace.c b/sysdeps/i386/backtrace.c
> index 124b0b73e3..4631f68fdc 100644
> --- a/sysdeps/i386/backtrace.c
> +++ b/sysdeps/i386/backtrace.c
> @@ -17,52 +17,18 @@
> License along with the GNU C Library; if not, see
> <https://www.gnu.org/licenses/>. */
>
> -#include <libc-lock.h>
> -#include <dlfcn.h>
> #include <execinfo.h>
> #include <stdlib.h>
> -#include <unwind.h>
> +#include <unwind-link.h>
>
> struct trace_arg
> {
> void **array;
> + struct unwind_link *unwind_link;
> int cnt, size;
> void *lastebp, *lastesp;
> };
>
> -#ifdef SHARED
> -static _Unwind_Reason_Code (*unwind_backtrace) (_Unwind_Trace_Fn, void *);
> -static _Unwind_Ptr (*unwind_getip) (struct _Unwind_Context *);
> -static _Unwind_Ptr (*unwind_getcfa) (struct _Unwind_Context *);
> -static _Unwind_Ptr (*unwind_getgr) (struct _Unwind_Context *, int);
> -static void *libgcc_handle;
> -
> -static void
> -init (void)
> -{
> - libgcc_handle = __libc_dlopen ("libgcc_s.so.1");
> -
> - if (libgcc_handle == NULL)
> - return;
> -
> - unwind_backtrace = __libc_dlsym (libgcc_handle, "_Unwind_Backtrace");
> - unwind_getip = __libc_dlsym (libgcc_handle, "_Unwind_GetIP");
> - unwind_getcfa = __libc_dlsym (libgcc_handle, "_Unwind_GetCFA");
> - unwind_getgr = __libc_dlsym (libgcc_handle, "_Unwind_GetGR");
> - if (unwind_getip == NULL || unwind_getgr == NULL || unwind_getcfa == NULL)
> - {
> - unwind_backtrace = NULL;
> - __libc_dlclose (libgcc_handle);
> - libgcc_handle = NULL;
> - }
> -}
> -#else
> -# define unwind_backtrace _Unwind_Backtrace
> -# define unwind_getip _Unwind_GetIP
> -# define unwind_getcfa _Unwind_GetCFA
> -# define unwind_getgr _Unwind_GetGR
> -#endif
> -
> static _Unwind_Reason_Code
> backtrace_helper (struct _Unwind_Context *ctx, void *a)
> {
> @@ -71,13 +37,16 @@ backtrace_helper (struct _Unwind_Context *ctx, void *a)
> /* We are first called with address in the __backtrace function.
> Skip it. */
> if (arg->cnt != -1)
> - arg->array[arg->cnt] = (void *) unwind_getip (ctx);
> + arg->array[arg->cnt]
> + = (void *) UNWIND_LINK_PTR (arg->unwind_link, _Unwind_GetIP) (ctx);
> if (++arg->cnt == arg->size)
> return _URC_END_OF_STACK;
>
> /* %ebp is DWARF2 register 5 on IA-32. */
> - arg->lastebp = (void *) unwind_getgr (ctx, 5);
> - arg->lastesp = (void *) unwind_getcfa (ctx);
> + arg->lastebp
> + = (void *) UNWIND_LINK_PTR (arg->unwind_link, _Unwind_GetGR) (ctx, 5);
> + arg->lastesp
> + = (void *) UNWIND_LINK_PTR (arg->unwind_link, _Unwind_GetCFA) (ctx);
> return _URC_NO_REASON;
> }
>
> @@ -111,20 +80,19 @@ struct layout
> int
> __backtrace (void **array, int size)
> {
> - struct trace_arg arg = { .array = array, .size = size, .cnt = -1 };
> -
> - if (size <= 0)
> - return 0;
> -
> -#ifdef SHARED
> - __libc_once_define (static, once);
> + struct trace_arg arg =
> + {
> + .array = array,
> + .unwind_link = __libc_unwind_link_get (),
> + .size = size,
> + .cnt = -1,
> + };
>
> - __libc_once (once, init);
> - if (unwind_backtrace == NULL)
> + if (size <= 0 || arg.unwind_link == NULL)
> return 0;
> -#endif
>
> - unwind_backtrace (backtrace_helper, &arg);
> + UNWIND_LINK_PTR (arg.unwind_link, _Unwind_Backtrace)
> + (backtrace_helper, &arg);
>
> if (arg.cnt > 1 && arg.array[arg.cnt - 1] == NULL)
> --arg.cnt;
> @@ -147,17 +115,3 @@ __backtrace (void **array, int size)
> }
> weak_alias (__backtrace, backtrace)
> libc_hidden_def (__backtrace)
> -
> -
> -#ifdef SHARED
> -/* Free all resources if necessary. */
> -libc_freeres_fn (free_mem)
> -{
> - unwind_backtrace = NULL;
> - if (libgcc_handle != NULL)
> - {
> - __libc_dlclose (libgcc_handle);
> - libgcc_handle = NULL;
> - }
> -}
> -#endif
>
--
Cheers,
Carlos.
next prev parent reply other threads:[~2021-03-01 13:54 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-17 16:02 [PATCH 00/10] Unwinder interface consolidation Florian Weimer
2021-02-17 16:02 ` [PATCH 01/10] Implement <unwind-link.h> for dynamically loading the libgcc_s unwinder Florian Weimer
2021-03-01 13:54 ` Carlos O'Donell
2021-02-17 16:02 ` [PATCH 02/10] backtrace: Implement on top of <unwind-link.h> Florian Weimer
2021-03-01 13:54 ` Carlos O'Donell
2021-02-17 16:02 ` [PATCH 03/10] arm: Implement backtrace " Florian Weimer
2021-03-01 13:54 ` Carlos O'Donell
2021-02-17 16:03 ` [PATCH 04/10] i386: " Florian Weimer
2021-03-01 13:54 ` Carlos O'Donell [this message]
2021-02-17 16:03 ` [PATCH 05/10] m68k: " Florian Weimer
2021-03-01 13:54 ` Carlos O'Donell
2021-02-17 16:03 ` [PATCH 06/10] sparc: Implement backtrace on top <unwind-link.h> Florian Weimer
2021-03-01 13:54 ` Carlos O'Donell
2021-02-17 16:03 ` [PATCH 07/10] __frame_state_for: Use <unwind-link.h> for unwinder access Florian Weimer
2021-03-01 13:54 ` Carlos O'Donell
2021-02-17 16:03 ` [PATCH 08/10] Move sysdeps/gnu/unwind-resume.c to sysdeps/generic/unwind-resume.c Florian Weimer
2021-03-01 13:55 ` Carlos O'Donell
2021-02-17 16:03 ` [PATCH 09/10] Implement _Unwind_Resume in libc on top of <unwind-link.h> Florian Weimer
2021-03-01 13:55 ` Carlos O'Donell
2021-02-17 16:03 ` [PATCH 10/10] nptl: Use <unwind-link.h> for accessing the libgcc_s unwinder Florian Weimer
2021-03-01 13:55 ` Carlos O'Donell
2021-03-01 13:54 ` [PATCH 00/10] Unwinder interface consolidation Carlos O'Donell
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