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From: Florian Weimer <fw@sourceware.org> To: glibc-cvs@sourceware.org Subject: [glibc/fw/unwind-link] backtrace: Implement on top of <unwind-link.h> Date: Thu, 13 Feb 2020 16:22:00 -0000 [thread overview] Message-ID: <20200213162214.127944.qmail@sourceware.org> (raw) https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=d3791ea298113a835b913bbf385f084eb09e4b2e commit d3791ea298113a835b913bbf385f084eb09e4b2e Author: Florian Weimer <fweimer@redhat.com> Date: Mon Feb 10 14:58:41 2020 +0100 backtrace: Implement on top of <unwind-link.h> This reimplements the generic version of backtrace. Diff: --- debug/backtrace.c | 86 ++++++++++++------------------------------------------- 1 file changed, 18 insertions(+), 68 deletions(-) diff --git a/debug/backtrace.c b/debug/backtrace.c index cc4b9a5..921c905 100644 --- a/debug/backtrace.c +++ b/debug/backtrace.c @@ -17,57 +17,19 @@ 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> 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) { @@ -77,10 +39,12 @@ 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); /* 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) @@ -95,20 +59,20 @@ 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. */ @@ -118,17 +82,3 @@ __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
next reply other threads:[~2020-02-13 16:22 UTC|newest] Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-02-13 16:22 Florian Weimer [this message] -- strict thread matches above, loose matches on Subject: below -- 2020-02-13 10:46 Florian Weimer 2020-02-10 17:09 Florian Weimer
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