From ffec7b2740bd6377b054438779228989c61ea82c Mon Sep 17 00:00:00 2001 From: Joseph Myers Date: Wed, 21 Mar 2018 17:25:30 +0000 Subject: [PATCH] Use x86_64 backtrace as generic version. No glibc configuration uses the present debug/backtrace.c, whereas several #include the x86_64 version. The x86_64 version is effectively a generic one (using _Unwind_Backtrace from libgcc, which works much more reliably than the built-in functions used by debug/backtrace.c). This patch moves it to debug/backtrace.c and removes all the #includes of the x86_64 version from other architectures which are no longer required. I do not know whether all the other architecture-specific backtrace implementations that are based on _Unwind_Backtrace are required, or whether, where their differences from the generic version do something useful, suitable hooks could be added to the generic version to reduce the duplication involved. Tested with build-many-glibcs.py that installed stripped shared libraries are unchanged by this patch. * sysdeps/x86_64/backtrace.c: Move to .... * debug/backtrace.c: ... here. * sysdeps/aarch64/backtrace.c: Remove file. * sysdeps/alpha/backtrace.c: Likewise. * sysdeps/hppa/backtrace.c: Likewise. * sysdeps/ia64/backtrace.c: Likewise. * sysdeps/mips/backtrace.c: Likewise. * sysdeps/nios2/backtrace.c: Likewise. * sysdeps/riscv/backtrace.c: Likewise. * sysdeps/sh/backtrace.c: Likewise. * sysdeps/tile/backtrace.c: Likewise. --- ChangeLog | 14 ++++ debug/backtrace.c | 150 +++++++++++++++++++++++------------- sysdeps/aarch64/backtrace.c | 1 - sysdeps/alpha/backtrace.c | 1 - sysdeps/hppa/backtrace.c | 1 - sysdeps/ia64/backtrace.c | 1 - sysdeps/mips/backtrace.c | 1 - sysdeps/nios2/backtrace.c | 1 - sysdeps/riscv/backtrace.c | 1 - sysdeps/sh/backtrace.c | 1 - sysdeps/tile/backtrace.c | 1 - sysdeps/x86_64/backtrace.c | 134 -------------------------------- 12 files changed, 111 insertions(+), 196 deletions(-) delete mode 100644 sysdeps/aarch64/backtrace.c delete mode 100644 sysdeps/alpha/backtrace.c delete mode 100644 sysdeps/hppa/backtrace.c delete mode 100644 sysdeps/ia64/backtrace.c delete mode 100644 sysdeps/mips/backtrace.c delete mode 100644 sysdeps/nios2/backtrace.c delete mode 100644 sysdeps/riscv/backtrace.c delete mode 100644 sysdeps/sh/backtrace.c delete mode 100644 sysdeps/tile/backtrace.c delete mode 100644 sysdeps/x86_64/backtrace.c diff --git a/ChangeLog b/ChangeLog index c26bdd2194..b3e6b4150f 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,17 @@ +2018-03-21 Joseph Myers + + * sysdeps/x86_64/backtrace.c: Move to .... + * debug/backtrace.c: ... here. + * sysdeps/aarch64/backtrace.c: Remove file. + * sysdeps/alpha/backtrace.c: Likewise. + * sysdeps/hppa/backtrace.c: Likewise. + * sysdeps/ia64/backtrace.c: Likewise. + * sysdeps/mips/backtrace.c: Likewise. + * sysdeps/nios2/backtrace.c: Likewise. + * sysdeps/riscv/backtrace.c: Likewise. + * sysdeps/sh/backtrace.c: Likewise. + * sysdeps/tile/backtrace.c: Likewise. + 2018-03-20 Joseph Myers [BZ #22987] diff --git a/debug/backtrace.c b/debug/backtrace.c index 60d4a15232..d423cc053a 100644 --- a/debug/backtrace.c +++ b/debug/backtrace.c @@ -1,7 +1,7 @@ -/* Return backtrace of current program state. Generic version. - Copyright (C) 1998-2018 Free Software Foundation, Inc. +/* Return backtrace of current program state. + Copyright (C) 2003-2018 Free Software Foundation, Inc. This file is part of the GNU C Library. - Contributed by Ulrich Drepper , 1998. + Contributed by Jakub Jelinek , 2003. The GNU C Library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public @@ -17,74 +17,118 @@ License along with the GNU C Library; if not, see . */ +#include +#include #include -#include -#include -#include -#include +#include +#include +#include -/* This implementation assumes a stack layout that matches the defaults - used by gcc's `__builtin_frame_address' and `__builtin_return_address' - (FP is the frame pointer register): +struct trace_arg +{ + void **array; + _Unwind_Word cfa; + int cnt; + int size; +}; - +-----------------+ +-----------------+ - FP -> | previous FP --------> | previous FP ------>... - | | | | - | return address | | return address | - +-----------------+ +-----------------+ +#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; - */ -/* Get some notion of the current stack. Need not be exactly the top - of the stack, just something somewhere in the current frame. */ -#ifndef CURRENT_STACK_FRAME -# define CURRENT_STACK_FRAME ({ char __csf; &__csf; }) +/* 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 -/* By default we assume that the stack grows downward. */ -#ifndef INNER_THAN -# define INNER_THAN < -#endif +static _Unwind_Reason_Code +backtrace_helper (struct _Unwind_Context *ctx, void *a) +{ + struct trace_arg *arg = a; -/* By default assume the `next' pointer in struct layout points to the - next struct layout. */ -#ifndef ADVANCE_STACK_FRAME -# define ADVANCE_STACK_FRAME(next) ((struct layout *) (next)) -#endif + /* We are first called with address in the __backtrace function. + Skip it. */ + if (arg->cnt != -1) + { + arg->array[arg->cnt] = (void *) unwind_getip (ctx); -/* By default, the frame pointer is just what we get from gcc. */ -#ifndef FIRST_FRAME_POINTER -# define FIRST_FRAME_POINTER __builtin_frame_address (0) -#endif + /* Check whether we make any progress. */ + _Unwind_Word cfa = unwind_getcfa (ctx); + + if (arg->cnt > 0 && arg->array[arg->cnt - 1] == arg->array[arg->cnt] + && cfa == arg->cfa) + return _URC_END_OF_STACK; + arg->cfa = cfa; + } + if (++arg->cnt == arg->size) + return _URC_END_OF_STACK; + return _URC_NO_REASON; +} int __backtrace (void **array, int size) { - struct layout *current; - void *top_frame; - void *top_stack; - int cnt = 0; + struct trace_arg arg = { .array = array, .cfa = 0, .size = size, .cnt = -1 }; - top_frame = FIRST_FRAME_POINTER; - top_stack = CURRENT_STACK_FRAME; + if (size <= 0) + return 0; - /* We skip the call to this function, it makes no sense to record it. */ - current = ((struct layout *) top_frame); - while (cnt < size) - { - if ((void *) current INNER_THAN top_stack - || !((void *) current INNER_THAN __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; +#ifdef SHARED + __libc_once_define (static, once); - array[cnt++] = current->return_address; + __libc_once (once, init); + if (unwind_backtrace == NULL) + return 0; +#endif - current = ADVANCE_STACK_FRAME (current->next); - } + unwind_backtrace (backtrace_helper, &arg); - return cnt; + /* _Unwind_Backtrace seems to put NULL address above + _start. Fix it up here. */ + if (arg.cnt > 1 && arg.array[arg.cnt - 1] == NULL) + --arg.cnt; + return arg.cnt != -1 ? arg.cnt : 0; } 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 diff --git a/sysdeps/aarch64/backtrace.c b/sysdeps/aarch64/backtrace.c deleted file mode 100644 index 27ce597b39..0000000000 --- a/sysdeps/aarch64/backtrace.c +++ /dev/null @@ -1 +0,0 @@ -#include diff --git a/sysdeps/alpha/backtrace.c b/sysdeps/alpha/backtrace.c deleted file mode 100644 index 27ce597b39..0000000000 --- a/sysdeps/alpha/backtrace.c +++ /dev/null @@ -1 +0,0 @@ -#include diff --git a/sysdeps/hppa/backtrace.c b/sysdeps/hppa/backtrace.c deleted file mode 100644 index 27ce597b39..0000000000 --- a/sysdeps/hppa/backtrace.c +++ /dev/null @@ -1 +0,0 @@ -#include diff --git a/sysdeps/ia64/backtrace.c b/sysdeps/ia64/backtrace.c deleted file mode 100644 index 27ce597b39..0000000000 --- a/sysdeps/ia64/backtrace.c +++ /dev/null @@ -1 +0,0 @@ -#include diff --git a/sysdeps/mips/backtrace.c b/sysdeps/mips/backtrace.c deleted file mode 100644 index 27ce597b39..0000000000 --- a/sysdeps/mips/backtrace.c +++ /dev/null @@ -1 +0,0 @@ -#include diff --git a/sysdeps/nios2/backtrace.c b/sysdeps/nios2/backtrace.c deleted file mode 100644 index 27ce597b39..0000000000 --- a/sysdeps/nios2/backtrace.c +++ /dev/null @@ -1 +0,0 @@ -#include diff --git a/sysdeps/riscv/backtrace.c b/sysdeps/riscv/backtrace.c deleted file mode 100644 index 27ce597b39..0000000000 --- a/sysdeps/riscv/backtrace.c +++ /dev/null @@ -1 +0,0 @@ -#include diff --git a/sysdeps/sh/backtrace.c b/sysdeps/sh/backtrace.c deleted file mode 100644 index 4f3eafb09c..0000000000 --- a/sysdeps/sh/backtrace.c +++ /dev/null @@ -1 +0,0 @@ -#include "../x86_64/backtrace.c" diff --git a/sysdeps/tile/backtrace.c b/sysdeps/tile/backtrace.c deleted file mode 100644 index 27ce597b39..0000000000 --- a/sysdeps/tile/backtrace.c +++ /dev/null @@ -1 +0,0 @@ -#include diff --git a/sysdeps/x86_64/backtrace.c b/sysdeps/x86_64/backtrace.c deleted file mode 100644 index d423cc053a..0000000000 --- a/sysdeps/x86_64/backtrace.c +++ /dev/null @@ -1,134 +0,0 @@ -/* Return backtrace of current program state. - Copyright (C) 2003-2018 Free Software Foundation, Inc. - This file is part of the GNU C Library. - Contributed by Jakub Jelinek , 2003. - - The GNU C Library is free software; you can redistribute it and/or - modify it under the terms of the GNU Lesser General Public - License as published by the Free Software Foundation; either - version 2.1 of the License, or (at your option) any later version. - - The GNU C Library is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public - License along with the GNU C Library; if not, see - . */ - -#include -#include -#include -#include -#include -#include - -struct trace_arg -{ - void **array; - _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) -{ - 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); - - /* Check whether we make any progress. */ - _Unwind_Word cfa = unwind_getcfa (ctx); - - if (arg->cnt > 0 && arg->array[arg->cnt - 1] == arg->array[arg->cnt] - && cfa == arg->cfa) - return _URC_END_OF_STACK; - arg->cfa = cfa; - } - if (++arg->cnt == arg->size) - return _URC_END_OF_STACK; - return _URC_NO_REASON; -} - -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) - return 0; -#endif - - unwind_backtrace (backtrace_helper, &arg); - - /* _Unwind_Backtrace seems to put NULL address above - _start. Fix it up here. */ - if (arg.cnt > 1 && arg.array[arg.cnt - 1] == NULL) - --arg.cnt; - return arg.cnt != -1 ? arg.cnt : 0; -} -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