cacao-initial-native: Fix undefined behaviour in gc

Upstream-Status: Backport

Fixes undefined behaviour in boehm GC used by cacao-initial-native
as suggested at
https://github.com/ivmai/bdwgc/commit/16780405c899f01119bc45167122b4242f6b34fb.

The undefined behaviour at very least causes a segmentation fault during
classpath-native configure step with Fedora 22.

Signed-off-by: Erkka Kääriä <erkka.kaaria@intel.com>
Signed-off-by: Maxin B. John <maxin.john@intel.com>

1 files changed, 35 insertions, 0 deletions

diff --git a/recipes-core/cacao/files/cacao-0.9.8-initial-fix-gc-undefined-behaviour.patch b/recipes-core/cacao/files/cacao-0.9.8-initial-fix-gc-undefined-behaviour.patch
new file mode 100644
index 0000000..ccc35cb
--- /dev/null
+++ b/recipes-core/cacao/files/cacao-0.9.8-initial-fix-gc-undefined-behaviour.patch
@@ -0,0 +1,35 @@
+Upstream-Status: Backport
+
+This fixes undefined behaviour in boehm GC as suggested at
+https://github.com/ivmai/bdwgc/commit/16780405c899f01119bc45167122b4242f6b34fb.
+
+The undefined behaviour at very least causes a segmentation fault during
+classpath-native configure step.
+    
+Signed-off-by: Erkka Kääriä <erkka.kaaria@intel.com>
+
+--- cacao-0.98/src/mm/boehm-gc/mark_rts.c
++++ cacao-0.98/src/mm/boehm-gc/mark_rts.c
+@@ -371,18 +371,7 @@ ptr_t p;
+ 
+ ptr_t GC_approx_sp()
+ {
+-    VOLATILE word dummy;
+-
+-    dummy = 42;        /* Force stack to grow if necessary.    Otherwise the   */
+-               /* later accesses might cause the kernel to think we're */
+-               /* doing something wrong.                               */
+-#   ifdef _MSC_VER
+-#     pragma warning(disable:4172)
+-#   endif
+-    return((ptr_t)(&dummy));
+-#   ifdef _MSC_VER
+-#     pragma warning(default:4172)
+-#   endif
++    return __builtin_frame_address(0);
+ }
+ 
+ /*
+-- 
+2.1.4
+