libubacktrace: Provide uClibc with backtrace functions

A new shared object, libubacktrace.so.0 is added to uClibc
to provide backtrace functions to support application self-debugging.
This set of functions requires to dynamically load libgcc_s.so so they
need to call dlopen/dlsym that are provided by libdl. For this reason
they cannot be included into libc.so.0 but are provided by a new library.

User application that wants to use backtrace needs to be compiled with
-fexceptions option and -rdynamic to get full symbols printed and must be
linked against libubacktrace.so

Signed-off-by: Carmelo Amoroso <carmelo.amoroso@st.com>

1 files changed, 19 insertions, 0 deletions

diff --git a/extra/Configs/Config.in b/extra/Configs/Config.in
index 7f0ac9db6..e8d522d71 100644
--- a/extra/Configs/Config.in
+++ b/extra/Configs/Config.in
@@ -2308,6 +2308,25 @@ config UCLIBC_MALLOC_DEBUGGING
 	  Because this increases the size of malloc appreciably (due to strings
 	  etc), you should say N unless you need to debug a malloc problem.
 
+config UCLIBC_HAS_BACKTRACE
+	bool "Add support for application self-debugging"
+	depends on HAVE_SHARED && TARGET_sh
+	default n
+	help
+	  Answer Y here to compile support for application self-debugging, by adding
+	  a new shared object "libubacktrace.so" that provides the following new
+	  functions:
+	  backtrace, backtrace_symbols, backtrace_symbols_fd
+
+	  The backtrace functionality is currently supported on SH platform, and it
+	  based on dwarf2 informations to properly work, so any application that
+	  want to use backtrace needs to be built with -fexceptions flag.
+
+	  The symbol names may be unavailable without the use of special linker
+	  options. For systems using the GNU linker, it is necessary to use the
+	  -rdynamic linker option too. Note that names of "static" functions are not
+	  exposed, and won't be available in the backtrace.
+
 config WARNINGS
 	string "Compiler Warnings"
 	default "-Wall"