[PATCH] libubacktrace: Add arm implementation

Khem Raj raj.khem at gmail.com
Sat Jan 21 19:42:06 UTC 2012


On Sat, Jan 21, 2012 at 6:47 AM, Carmelo AMOROSO <carmelo.amoroso at st.com> wrote:
> On 21/01/2012 15.08, Khem Raj wrote:
>> Arm has a different mechanism of getting
>> _Unwind_GetIP. Therefore we profile arch
>> specific backtrace file.
>>
>> Signed-off-by: Khem Raj <raj.khem at gmail.com>
>> ---
>>  libubacktrace/Makefile.in       |   26 ++++++++--
>>  libubacktrace/arm/Makefile.arch |   21 ++++++++
>>  libubacktrace/arm/backtrace.c   |  104 +++++++++++++++++++++++++++++++++++++++
>>  3 files changed, 145 insertions(+), 6 deletions(-)
>>  create mode 100644 libubacktrace/arm/Makefile.arch
>>  create mode 100644 libubacktrace/arm/backtrace.c
>>
>> diff --git a/libubacktrace/Makefile.in b/libubacktrace/Makefile.in
>> index b18e3e6..f675bf5 100644
>> --- a/libubacktrace/Makefile.in
>> +++ b/libubacktrace/Makefile.in
>> @@ -6,7 +6,7 @@
>>  # Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
>>  #
>>
>> -subdirs += libubacktrace
>> +subdirs += libubacktrace libubacktrace/$(TARGET_ARCH)
>>
>>  CFLAGS-libubacktrace := -DNOT_IN_libc -DIS_IN_libubacktrace $(SSP_ALL_CFLAGS)
>>
>> @@ -23,22 +23,36 @@ libubacktrace_FULL_NAME := libubacktrace-$(VERSION).so
>>  libubacktrace_DIR := $(top_srcdir)libubacktrace
>>  libubacktrace_OUT := $(top_builddir)libubacktrace
>>
>> +libubacktrace_ARCH_DIR:=$(libubacktrace_DIR)/$(TARGET_ARCH)
>> +libubacktrace_ARCH_OUT:=$(libubacktrace_OUT)/$(TARGET_ARCH)
>> +
>> +-include $(libubacktrace_ARCH_DIR)/Makefile.arch
>> +
>>  libubacktrace_SRC-y :=
>>  libubacktrace_SRC-$(UCLIBC_HAS_BACKTRACE) := backtrace.c backtracesyms.c backtracesymsfd.c
>>
>> +# remove generic sources, if arch specific version is present
>> +ifneq ($(strip $(libubacktrace_ARCH_SRC-y)),)
>> +libubacktrace_SRC-y := $(filter-out $(notdir $(libubacktrace_ARCH_SRC-y)),$(libubacktrace_SRC-y))
>> +endif
>> +
>>  # -fasynchronous-unwind-tables is required for backtrace to work using dwarf2
>>  CFLAGS-backtrace.c := -fasynchronous-unwind-tables
>>
>> +# pass common flags to arch dirs
>> +ifneq ($(strip $(libubacktrace_ARCH_OBJS)),)
>> +CFLAGS-libubacktrace/$(TARGET_ARCH)/ := $(CFLAGS-libubacktrace)
>> +endif
>>
>> -libubacktrace_SRCS := $(addprefix $(libubacktrace_DIR)/,$(libubacktrace_SRC-y))
>> +libubacktrace_SRCS := $(patsubst %.c,$(libubacktrace_DIR)/%.c,$(libubacktrace_SRC-y))
>>  libubacktrace_OBJS := $(patsubst $(libubacktrace_DIR)/%.c,$(libubacktrace_OUT)/%.o,$(libubacktrace_SRCS))
>>
>>  ifeq ($(DOPIC),y)
>> -libubacktrace-a-y := $(libubacktrace_OBJS:.o=.os)
>> +libubacktrace-a-y += $(libubacktrace_OBJS:.o=.os)
>>  else
>> -libubacktrace-a-y := $(libubacktrace_OBJS)
>> +libubacktrace-a-y += $(libubacktrace_OBJS)
>>  endif
>> -libubacktrace-so-y := $(libubacktrace_OBJS:.o=.os)
>> +libubacktrace-so-y += $(libubacktrace_OBJS:.o=.os)
>>
>>  lib-a-$(UCLIBC_HAS_BACKTRACE) += $(top_builddir)lib/libubacktrace.a
>>  lib-so-$(UCLIBC_HAS_BACKTRACE) += $(top_builddir)lib/libubacktrace.so
>> @@ -61,7 +75,7 @@ $(libubacktrace_OUT)/libubacktrace_so.a: $(libubacktrace-so-y)
>>       $(Q)$(RM) $@
>>       $(do_ar)
>>
>> -$(libubacktrace_OUT)/libubacktrace.oS: $(libubacktrace_SRCS)
>> +$(libubacktrace_OUT)/libubacktrace.oS: $(libubacktrace_SRCS) $(libubacktrace_ARCH_SRCS)
>>       $(Q)$(RM) $@
>>       $(compile-m)
>>
>> diff --git a/libubacktrace/arm/Makefile.arch b/libubacktrace/arm/Makefile.arch
>> new file mode 100644
>> index 0000000..dab3637
>> --- /dev/null
>> +++ b/libubacktrace/arm/Makefile.arch
>> @@ -0,0 +1,21 @@
>> +# Makefile for uClibc (libubacktrace)
>> +#
>> +# Author: Khem Raj <raj.khem at gmail.com>
>> +
>> +# Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
>> +#
>> +
>> +libubacktrace_ARCH_SRC-$(UCLIBC_HAS_BACKTRACE) := backtrace.c
>> +libubacktrace_ARCH_SRCS := $(addprefix $(libubacktrace_ARCH_DIR)/,$(libubacktrace_ARCH_SRC-y))
>> +libubacktrace_ARCH_OBJS := $(patsubst $(libubacktrace_ARCH_DIR)/%.c,$(libubacktrace_ARCH_OUT)/%.o,$(libubacktrace_ARCH_SRCS))
>> +
>> +ifeq ($(DOPIC),y)
>> +libubacktrace-a-y+=$(libubacktrace_ARCH_OBJS:.o=.os)
>> +else
>> +libubacktrace-a-y+=$(libubacktrace_ARCH_OBJS)
>> +endif
>> +libubacktrace-so-y+=$(libubacktrace_ARCH_OBJS:.o=.os)
>> +
>> +ifeq ($(CONFIG_ARM_EABI),y)
>> +LIBGCC += $(shell $(CC) -print-file-name=libgcc_eh.a)
>> +endif
>
> with my proposed patch to move __aeabi_unwind_cpp_pr in uclibc_shared.a
> should not be needed.

lets make this change after you have installed that patch. For now I will
keep it.

>
>> diff --git a/libubacktrace/arm/backtrace.c b/libubacktrace/arm/backtrace.c
>> new file mode 100644
>> index 0000000..8a18c6c
>> --- /dev/null
>> +++ b/libubacktrace/arm/backtrace.c
>> @@ -0,0 +1,104 @@
>> +/*
>> + * Perform stack unwinding by using the _Unwind_Backtrace.
>> + *
>> + * User application that wants to use backtrace needs to be
>> + * compiled with -fexceptions option and -rdynamic to get full
>> + * symbols printed.
>> + *
>> + * Copyright (C) 2009, 2010 STMicroelectronics Ltd.
>> + *
>> + * Author(s): Giuseppe Cavallaro <peppe.cavallaro at st.com>
>> + * - Initial implementation for glibc
>> + *
>> + * Author(s): Carmelo Amoroso <carmelo.amoroso at st.com>
>> + * - Reworked for uClibc
>> + *   - use dlsym/dlopen from libdl
>> + *   - rewrite initialisation to not use libc_once
>> + *   - make it available in static link too
>> + *
>
> fell free to remove old authorship

ok

>
>> + * Author(s): Khem Raj <raj.khem at gmail.com>
>> + * - Add arm specific implementation
>> + *
>> + * Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
>> + *
>> + */
>> +
>> +#include <execinfo.h>
>> +#include <dlfcn.h>
>> +#include <stdlib.h>
>> +#include <unwind.h>
>> +#include <assert.h>
>> +#include <stdio.h>
>> +
>> +struct trace_arg
>> +{
>> +  void **array;
>> +  int cnt, size;
>> +};
>> +
>> +static _Unwind_Reason_Code (*unwind_backtrace) (_Unwind_Trace_Fn, void *);
>> +static _Unwind_VRS_Result (*unwind_vrs_get) (_Unwind_Context *,
>> +                                          _Unwind_VRS_RegClass,
>> +                                          _uw,
>> +                                          _Unwind_VRS_DataRepresentation,
>> +                                          void *);
>> +
>> +static void backtrace_init (void)
>> +{
>> +     void *handle = dlopen ("libgcc_s.so.1", RTLD_LAZY);
>> +     if (handle == NULL
>> +             || ((unwind_backtrace = dlsym (handle, "_Unwind_Backtrace")) == NULL)
>> +             || ((unwind_vrs_get = dlsym (handle, "_Unwind_VRS_Get")) == NULL)) {
>> +             printf("libgcc_s.so.1 must be installed for backtrace to work\n");
>> +             abort();
>> +     }
>> +}
>> +/* This function is identical to "_Unwind_GetGR", except that it uses
>> +   "unwind_vrs_get" instead of "_Unwind_VRS_Get".  */
>> +static inline _Unwind_Word
>> +unwind_getgr (_Unwind_Context *context, int regno)
>> +{
>> +  _uw val;
>> +  unwind_vrs_get (context, _UVRSC_CORE, regno, _UVRSD_UINT32, &val);
>> +  return val;
>> +}
>> +
>> +/* This macro is identical to the _Unwind_GetIP macro, except that it
>> +   uses "unwind_getgr" instead of "_Unwind_GetGR".  */
>> +#define unwind_getip(context) \
>> + (unwind_getgr (context, 15) & ~(_Unwind_Word)1)
>> +
>> +static _Unwind_Reason_Code
>> +backtrace_helper (struct _Unwind_Context *ctx, void *a)
>> +{
>> +     struct trace_arg *arg = a;
>> +
>> +     assert (unwind_getip != NULL);
>> +
>> +     /* 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;
>> +     return _URC_NO_REASON;
>> +}
>> +
>> +/*
>> + * Perform stack unwinding by using the _Unwind_Backtrace.
>> + *
>> + * User application that wants to use backtrace needs to be
>> + * compiled with -fexceptions option and -rdynamic to get full
>
> -fasynchronous-unwid-tables shold be referenced, instead of -fexecptions

right. changed locally.

>
>> + * symbols printed.
>> + */
>> +int backtrace (void **array, int size)
>> +{
>> +     struct trace_arg arg = { .array = array, .size = size, .cnt = -1 };
>> +
>> +     if (unwind_backtrace == NULL)
>> +             backtrace_init();
>> +
>> +     if (size >= 1)
>> +             unwind_backtrace (backtrace_helper, &arg);
>> +
>> +     return arg.cnt != -1 ? arg.cnt : 0;
>> +}
>
> Cheers,
> Carmelo
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