tool_chain/cxx: use '__cxa_demangle()' for exception names

Fixes #1976

repos/base/src/lib/cxx/exception.cc

@@ -20,6 +20,11 @@
 
 extern "C" char __eh_frame_start__[];                  /* from linker script */
 extern "C" void __register_frame (const void *begin);  /* from libgcc_eh     */
+extern "C" char *__cxa_demangle(const char *mangled_name,
+                                char *output_buffer,
+                                size_t *length,
+                                int *status);
+extern "C" void free(void *ptr);
 
 /*
  * This symbol is overwritten by Genode's dynamic linker (ld.lib.so).
@@ -48,7 +53,14 @@ void terminate_handler()
 {
 	std::type_info *t = __cxxabiv1::__cxa_current_exception_type();
 
-	if (t)
+	if (!t)
+		return;
+
+	char *demangled_name = __cxa_demangle(t->name(), nullptr, nullptr, nullptr);
+	if (demangled_name) {
+		PERR("Uncaught exception of type '%s'", demangled_name);
+		free(demangled_name);
+	} else
 		PERR("Uncaught exception of type '%s' (use 'c++filt -t' to demangle)",
 		     t->name());
 }

repos/ports/ports/gcc.hash

@@ -1 +1 @@
-2a59b9a759881adf43812b5e6b8c5cd3dec8fb0d
+fe976d168f9937cac0ffaa7ec4999d385d076fe2

tool/patches/gcc-4.9.2/libsupcxx_demangle.patch

@@ -0,0 +1,86 @@
+Enable '___cxa_demangle()' in libsupc++
+
+From: Christian Prochaska <christian.prochaska@genode-labs.com>
+
+
+---
+ include/libiberty.h                |    4 ++++
+ libiberty/cp-demangle.c            |    4 +++-
+ libstdc++-v3/libsupc++/Makefile.in |   10 +++++-----
+ 3 files changed, 12 insertions(+), 6 deletions(-)
+
+diff --git a/include/libiberty.h b/include/libiberty.h
+index 78c42eb..4fcf284 100644
+--- a/include/libiberty.h
++++ b/include/libiberty.h
+@@ -47,7 +47,11 @@ extern "C" {
+ /* Get a definition for va_list.  */
+ #include <stdarg.h>
+ 
++#ifdef GENODE
++#define FILE void
++#else
+ #include <stdio.h>
++#endif
+ 
+ /* If the OS supports it, ensure that the supplied stream is setup to
+    avoid any multi-threaded locking.  Otherwise leave the FILE pointer
+diff --git a/libiberty/cp-demangle.c b/libiberty/cp-demangle.c
+index 3d5d33e..e5f542f 100644
+--- a/libiberty/cp-demangle.c
++++ b/libiberty/cp-demangle.c
+@@ -103,7 +103,9 @@
+ #include "config.h"
+ #endif
+ 
++#ifndef GENODE
+ #include <stdio.h>
++#endif
+ 
+ #ifdef HAVE_STDLIB_H
+ #include <stdlib.h>
+@@ -5875,7 +5877,7 @@ d_demangle (const char *mangled, int options, size_t *palc)
+   return dgs.buf;
+ }
+ 
+-#if defined(IN_LIBGCC2) || defined(IN_GLIBCPP_V3)
++#if defined(IN_LIBGCC2) || defined(IN_GLIBCPP_V3) || defined(GENODE)
+ 
+ extern char *__cxa_demangle (const char *, char *, size_t *, int *);
+ 
+diff --git a/libstdc++-v3/libsupc++/Makefile.in b/libstdc++-v3/libsupc++/Makefile.in
+index 88b237e..f861d29 100644
+--- a/libstdc++-v3/libsupc++/Makefile.in
++++ b/libstdc++-v3/libsupc++/Makefile.in
+@@ -104,7 +104,7 @@ am__objects_1 = array_type_info.lo atexit_arm.lo atexit_thread.lo \
+ 	new_opv.lo new_opvnt.lo pbase_type_info.lo pmem_type_info.lo \
+ 	pointer_type_info.lo pure.lo si_class_type_info.lo tinfo.lo \
+ 	tinfo2.lo vec.lo vmi_class_type_info.lo vterminate.lo
+-@GLIBCXX_HOSTED_TRUE@am__objects_2 = cp-demangle.lo
++am__objects_2 = cp-demangle.lo
+ @ENABLE_VTABLE_VERIFY_TRUE@am__objects_3 = vtv_stubs.lo
+ am_libsupc___la_OBJECTS = $(am__objects_1) $(am__objects_2) \
+ 	$(am__objects_3)
+@@ -367,8 +367,8 @@ bits_HEADERS = \
+ 	exception_defines.h exception_ptr.h hash_bytes.h nested_exception.h
+ 
+ headers = $(std_HEADERS) $(bits_HEADERS)
+-@GLIBCXX_HOSTED_TRUE@c_sources = \
+-@GLIBCXX_HOSTED_TRUE@	cp-demangle.c
++c_sources = \
++	cp-demangle.c
+ 
+ sources = \
+ 	array_type_info.cc \
+@@ -801,9 +801,9 @@ cp-demangle.c:
+ 	rm -f $@
+ 	$(LN_S) $(toplevel_srcdir)/libiberty/cp-demangle.c $@
+ cp-demangle.lo: cp-demangle.c
+-	$(LTCOMPILE) -DIN_GLIBCPP_V3 -Wno-error -c $<
++	$(LTCOMPILE) -DGENODE -Wno-error -c $<
+ cp-demangle.o: cp-demangle.c
+-	$(C_COMPILE) -DIN_GLIBCPP_V3 -Wno-error -c $<
++	$(C_COMPILE) -DGENODE -Wno-error -c $<
+ 
+ # Use special rules for the C++11 sources so that the proper flags are passed.
+ bad_array_length.lo: bad_array_length.cc

tool/patches/gcc-4.9.2/series

@@ -6,6 +6,7 @@ no_short_enums.patch
 host_target_combination.patch
 prefer_pic.patch
 libstdcxx_without_libc.patch
+libsupcxx_demangle.patch
 libgcc_s.patch
 go_libbacktrace.patch
 target_libbacktrace.patch