[PATCH] libubacktrace: Add arm implementation
Khem Raj
raj.khem at gmail.com
Sat Jan 21 14:08:42 UTC 2012
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
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
+ *
+ * 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
+ * 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;
+}
--
1.7.0.4
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