diff options
Diffstat (limited to 'sysdeps/i386')
| -rw-r--r-- | sysdeps/i386/Makefile | 4 | ||||
| -rw-r--r-- | sysdeps/i386/backtrace.c | 119 |
2 files changed, 99 insertions, 24 deletions
diff --git a/sysdeps/i386/Makefile b/sysdeps/i386/Makefile index fb14806029..52faaa3109 100644 --- a/sysdeps/i386/Makefile +++ b/sysdeps/i386/Makefile @@ -21,6 +21,10 @@ CFLAGS-dl-load.c += -Wno-unused CFLAGS-dl-reloc.c += -Wno-unused endif +ifeq ($(subdir),debug) +CFLAGS-backtrace.c += -fexceptions +endif + # Most of the glibc routines don't ever call user defined callbacks # nor use any FPU or SSE* and as such don't need bigger %esp alignment # than 4 bytes. diff --git a/sysdeps/i386/backtrace.c b/sysdeps/i386/backtrace.c index 10ff44d11d..cb7530396b 100644 --- a/sysdeps/i386/backtrace.c +++ b/sysdeps/i386/backtrace.c @@ -1,5 +1,5 @@ /* Return backtrace of current program state. - Copyright (C) 1998, 2000 Free Software Foundation, Inc. + Copyright (C) 1998, 2000, 2003, 2004 Free Software Foundation, Inc. This file is part of the GNU C Library. Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998. @@ -18,8 +18,64 @@ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. */ +#include <bits/libc-lock.h> +#include <dlfcn.h> #include <execinfo.h> -#include <bp-checks.h> +#include <stdlib.h> +#include <unwind.h> + +struct trace_arg +{ + void **array; + 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 +init (void) +{ + void *handle = __libc_dlopen ("libgcc_s.so.1"); + + if (handle == NULL) + return; + + unwind_backtrace = __libc_dlsym (handle, "_Unwind_Backtrace"); + unwind_getip = __libc_dlsym (handle, "_Unwind_GetIP"); + unwind_getcfa = __libc_dlsym (handle, "_Unwind_GetCFA"); + unwind_getgr = __libc_dlsym (handle, "_Unwind_GetGR"); + if (unwind_getip == NULL || unwind_getgr == NULL || unwind_getcfa == NULL) + unwind_backtrace = 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) +{ + struct trace_arg *arg = 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); + 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); + return _URC_NO_REASON; +} /* This is a global variable set at program start time. It marks the @@ -27,46 +83,61 @@ extern void *__libc_stack_end; -/* This is the stack alyout we see with every stack frame. +/* This is the stack layout we see with every stack frame + if not compiled without frame pointer. +-----------------+ +-----------------+ %ebp -> | %ebp last frame--------> | %ebp last frame--->... | | | | | return address | | return address | +-----------------+ +-----------------+ -*/ + + First try as far to get as far as possible using + _Unwind_Backtrace which handles -fomit-frame-pointer + as well, but requires .eh_frame info. Then fall back to + walking the stack manually. */ + struct layout { - struct layout *__unbounded next; - void *__unbounded return_address; + struct layout *ebp; + void *ret; }; + int __backtrace (array, size) void **array; int size; { - /* We assume that all the code is generated with frame pointers set. */ - register void *ebp __asm__ ("ebp"); - register void *esp __asm__ ("esp"); - struct layout *current; - int cnt = 0; - - /* We skip the call to this function, it makes no sense to record it. */ - current = BOUNDED_1 ((struct layout *) ebp); - while (cnt < size) + struct trace_arg arg = { .array = array, .size = size, .cnt = -1 }; +#ifdef SHARED + __libc_once_define (static, once); + + __libc_once (once, init); + if (unwind_backtrace == NULL) + return 0; +#endif + + if (size >= 1) + unwind_backtrace (backtrace_helper, &arg); + + if (arg.cnt > 1 && arg.array[arg.cnt - 1] == NULL) + --arg.cnt; + else if (arg.cnt < size) { - if ((void *) current < esp || (void *) current > __libc_stack_end) - /* This means the address is out of range. Note that for the - toplevel we see a frame pointer with value NULL which clearly is - out of range. */ - break; + struct layout *ebp = (struct layout *) arg.lastebp; - array[cnt++] = current->return_address; + while (arg.cnt < size) + { + /* Check for out of range. */ + if ((void *) ebp < arg.lastesp || (void *) ebp > __libc_stack_end + || ((long) ebp & 3)) + break; - current = current->next; + array[arg.cnt++] = ebp->ret; + ebp = ebp->ebp; + } } - - return cnt; + return arg.cnt != -1 ? arg.cnt : 0; } weak_alias (__backtrace, backtrace) |