[oe] [meta-java][PATCH] ecj-initial.in: Disable multithreading to mitigate segfaulting

[Erkka Kääriä]

Cacao-initial-native suffers from sporadic segmentation faults, when the Java
program uses multiple Java threads, due to a race condition. In particular,
jamvm-native and classpath-native builds would occasionally fail as the
eclipse compiler used during build task by default uses multiple threads.

As fixing the race condition would require large changes to the
cacao-initial-native codebase, and as it is only used briefly during the
bootstrapping process, it is easier and safer to just force ecj-initial to run
in a singlethreaded mode.

Signed-off-by: Erkka Kääriä <erkka.kaaria at intel.com>
---
 recipes-core/ecj/files/ecj-initial.in | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/recipes-core/ecj/files/ecj-initial.in b/recipes-core/ecj/files/ecj-initial.in
index 2099991..30c1c8a 100755
--- a/recipes-core/ecj/files/ecj-initial.in
+++ b/recipes-core/ecj/files/ecj-initial.in
@@ -1 +1,3 @@
-${RUNTIME} -Xmx512m -cp ${ECJ_JAR} org.eclipse.jdt.internal.compiler.batch.Main ${1+"$@"}
+# -Djdt.compiler.useSingleThread=true forces the compiler to only use a single thread. This is a workaround to a race condition
+# bug in cacao-initial-native, where using multiple java thread could cause sporadic segmentation faults
+${RUNTIME} -Xmx512m -Djdt.compiler.useSingleThread=true -cp ${ECJ_JAR} org.eclipse.jdt.internal.compiler.batch.Main ${1+"$@"}
-- 
2.1.4

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