From 808ff3714e43cf363399d7ec090dee2b204e9a47 Mon Sep 17 00:00:00 2001
From: Norman Feske <norman.feske@genode-labs.com>
Date: Thu, 22 Aug 2019 14:21:30 +0200
Subject: [PATCH] rust: don't export cxx syms from libunwind-rust

---
 repos/libports/lib/mk/libunwind-rust.mk | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/repos/libports/lib/mk/libunwind-rust.mk b/repos/libports/lib/mk/libunwind-rust.mk
index 378c91b9e..8de4f392f 100644
--- a/repos/libports/lib/mk/libunwind-rust.mk
+++ b/repos/libports/lib/mk/libunwind-rust.mk
@@ -3,3 +3,19 @@ LIBS = libcore-rust
 vpath % $(REP_DIR)/src/lib/rust/libunwind
 
 CC_CXX_WARN_STRICT =
+
+#
+# libunwind contains the public symbol '_Unwind_Resume', which clashes with
+# the symbol provided by the cxx library. The aliasing can lead to unexpected
+# symbol resolutions by the dynamic linker at runtime, i.e., a C++ exception
+# thrown in the libc ending up in the '_Unwind_Resume' code of libunwind-rust.
+#
+# This rule solves this uncertainty by making the symbol private to the
+# libunwind library.
+#
+ifeq ($(called_from_lib_mk),yes)
+$(LIB).lib.a: hide_cxx_symbols
+hide_cxx_symbols: lib.o
+	$(VERBOSE)cp $< $<.tmp
+	$(VERBOSE)$(OBJCOPY) --localize-symbol=_Unwind_Resume $<.tmp $<
+endif