From: Florian Weimer <fweimer@redhat.com>
To: libc-alpha@sourceware.org
Subject: [PATCH 02/10] backtrace: Implement on top of <unwind-link.h>
Date: Wed, 17 Feb 2021 17:02:52 +0100 [thread overview]
Message-ID: <5d751702e5e7ff0f502b447a0206326396e8be0b.1613577607.git.fweimer@redhat.com> (raw)
In-Reply-To: <cover.1613577607.git.fweimer@redhat.com>
This reimplements the generic version of backtrace.
---
debug/backtrace.c | 84 ++++++++++-------------------------------------
1 file changed, 17 insertions(+), 67 deletions(-)
diff --git a/debug/backtrace.c b/debug/backtrace.c
index 5ded57bfc4..187d911a0d 100644
--- a/debug/backtrace.c
+++ b/debug/backtrace.c
@@ -17,10 +17,7 @@
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 <gnu/lib-names.h>
#include <stdlib.h>
#include <unwind.h>
#include <unwind-link.h>
@@ -28,47 +25,12 @@
struct trace_arg
{
void **array;
+ struct unwind_link *unwind_link;
_Unwind_Word cfa;
int cnt;
int size;
};
-#ifdef SHARED
-static _Unwind_Reason_Code (*unwind_backtrace) (_Unwind_Trace_Fn, void *);
-static _Unwind_Ptr (*unwind_getip) (struct _Unwind_Context *);
-static _Unwind_Word (*unwind_getcfa) (struct _Unwind_Context *);
-static void *libgcc_handle;
-
-
-/* Dummy version in case libgcc_s does not contain the real code. */
-static _Unwind_Word
-dummy_getcfa (struct _Unwind_Context *ctx __attribute__ ((unused)))
-{
- return 0;
-}
-
-
-static void
-init (void)
-{
- libgcc_handle = __libc_dlopen (LIBGCC_S_SO);
-
- if (libgcc_handle == NULL)
- return;
-
- unwind_backtrace = __libc_dlsym (libgcc_handle, "_Unwind_Backtrace");
- unwind_getip = __libc_dlsym (libgcc_handle, "_Unwind_GetIP");
- if (unwind_getip == NULL)
- unwind_backtrace = NULL;
- unwind_getcfa = (__libc_dlsym (libgcc_handle, "_Unwind_GetCFA")
- ?: dummy_getcfa);
-}
-#else
-# define unwind_backtrace _Unwind_Backtrace
-# define unwind_getip _Unwind_GetIP
-# define unwind_getcfa _Unwind_GetCFA
-#endif
-
static _Unwind_Reason_Code
backtrace_helper (struct _Unwind_Context *ctx, void *a)
{
@@ -78,14 +40,16 @@ backtrace_helper (struct _Unwind_Context *ctx, void *a)
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 > 0)
arg->array[arg->cnt]
= unwind_arch_adjustment (arg->array[arg->cnt - 1],
arg->array[arg->cnt]);
/* Check whether we make any progress. */
- _Unwind_Word cfa = unwind_getcfa (ctx);
+ _Unwind_Word cfa
+ = UNWIND_LINK_PTR (arg->unwind_link, _Unwind_GetCFA) (ctx);
if (arg->cnt > 0 && arg->array[arg->cnt - 1] == arg->array[arg->cnt]
&& cfa == arg->cfa)
@@ -100,20 +64,20 @@ backtrace_helper (struct _Unwind_Context *ctx, void *a)
int
__backtrace (void **array, int size)
{
- struct trace_arg arg = { .array = array, .cfa = 0, .size = size, .cnt = -1 };
-
- if (size <= 0)
- return 0;
-
-#ifdef SHARED
- __libc_once_define (static, once);
-
- __libc_once (once, init);
- if (unwind_backtrace == NULL)
+ struct trace_arg arg =
+ {
+ .array = array,
+ .unwind_link = __libc_unwind_link_get (),
+ .cfa = 0,
+ .size = size,
+ .cnt = -1
+ };
+
+ 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);
/* _Unwind_Backtrace seems to put NULL address above
_start. Fix it up here. */
@@ -123,17 +87,3 @@ __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
--
2.29.2
next prev parent reply other threads:[~2021-02-17 16:02 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 ` Florian Weimer [this message]
2021-03-01 13:54 ` [PATCH 02/10] backtrace: Implement on top of <unwind-link.h> 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
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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