openjdk-8: gcc-8 fix #4: undefined behaviour (hotspot)

Using gcc-8, Hotspot is being miscompiled, resulting in non-
working binaries.

The reason is undefined behaviour, which gcc-8 even warns about
and errors out. We have so far have taped over those warnings,
but it turns out that we simply cannot do that.

Add patches to address undefined behaviour causing miscompilation
of hotsport.

This also means we can remove the -Wno-error=return-type C compiler
flag again which was recently added in error in
commit 52fb41cec7d5 ("openjdk-8: fix build for gcc8.x") only hiding
the compiler warnings/errors that were flagging the incorrect code
in the first place.

With these patches applied, the openjdk-8 ARM port works again:
| RESULTS:
| RESULTS - ping.PingTest.test_ping - Testcase 964: PASSED (0.04s)
| RESULTS - ssh.SSHTest.test_ssh - Testcase 224: PASSED (0.68s)
| RESULTS - java.JavaTest.test_java_exists - Testcase -1: PASSED (0.14s)
| RESULTS - java.JavaTest.test_java_jar_comp_mode - Testcase -1: FAILED (5.13s)
| RESULTS - java.JavaTest.test_java_jar_int_mode - Testcase -1: PASSED (4.48s)
| RESULTS - java.JavaTest.test_java_jar_works - Testcase -1: PASSED (4.44s)
| RESULTS - java.JavaTest.test_java_version - Testcase -1: PASSED (3.66s)
| RESULTS - javac.JavacTest.test_javac_exists - Testcase -1: PASSED (0.13s)
| RESULTS - javac.JavacTest.test_javac_works - Testcase -1: PASSED (30.87s)
| SUMMARY:
| openjdk-8-test-image () - Ran 9 tests in 50.263s

The java.JavaTest.test_java_jar_comp_mode failure can be ignored for now,
as that test verifies compiled mode which is not available on arm. The
testcase must be fixed instead.

(We need to refresh one unrelated existing patch to avoid patch fuzz warnings)

Signed-off-by: André Draszik <andre.draszik@jci.com>
Signed-off-by: Richard Leitner <richard.leitner@skidata.com>

1 files changed, 47 insertions, 0 deletions

diff --git a/recipes-core/openjdk/patches-openjdk-8/0018-hotspot-Fix-debug-build-after-8062808-Turn-on-the-Wr.patch b/recipes-core/openjdk/patches-openjdk-8/0018-hotspot-Fix-debug-build-after-8062808-Turn-on-the-Wr.patch
new file mode 100644
index 0000000..1421963
--- /dev/null
+++ b/recipes-core/openjdk/patches-openjdk-8/0018-hotspot-Fix-debug-build-after-8062808-Turn-on-the-Wr.patch
@@ -0,0 +1,47 @@
+From dbf31e2dfd00e20ab49af70f3533a348e8a6515e Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Andr=C3=A9=20Draszik?= <andre.draszik@jci.com>
+Date: Mon, 13 Aug 2018 16:47:25 +0100
+Subject: [PATCH 4/5] hotspot: Fix debug build after 8062808: Turn on the
+ -Wreturn-type warning
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+|# HG changeset patch
+|# User goetz
+|# Date 1415873641 -3600
+|#      Thu Nov 13 11:14:01 2014 +0100
+|# Node ID 1878c4c1d04e1f3c6f67a19d36c35863d6b5f906
+|# Parent  533473c67de6ff767710594639033c8e83523fe5
+8064786, PR3599: Fix debug build after 8062808: Turn on the -Wreturn-type warning
+Reviewed-by: stefank, tschatzl
+
+Signed-off-by: André Draszik <andre.draszik@jci.com>
+Upstream-Status: Backport
+---
+ hotspot/src/share/vm/prims/jni.cpp | 2 ++
+ 1 file changed, 2 insertions(+)
+
+diff --git a/hotspot/src/share/vm/prims/jni.cpp b/hotspot/src/share/vm/prims/jni.cpp
+index 6a6ab936..e2f2ad3b 100644
+--- a/hotspot/src/share/vm/prims/jni.cpp
++++ b/hotspot/src/share/vm/prims/jni.cpp
+@@ -708,6 +708,7 @@ JNI_ENTRY(jint, jni_Throw(JNIEnv *env, jthrowable obj))
+ 
+   THROW_OOP_(JNIHandles::resolve(obj), JNI_OK);
+   ShouldNotReachHere();
++  return 0;  // Mute compiler.
+ JNI_END
+ 
+ #ifndef USDT2
+@@ -734,6 +735,7 @@ JNI_ENTRY(jint, jni_ThrowNew(JNIEnv *env, jclass clazz, const char *message))
+   Handle protection_domain (THREAD, k->protection_domain());
+   THROW_MSG_LOADER_(name, (char *)message, class_loader, protection_domain, JNI_OK);
+   ShouldNotReachHere();
++  return 0;  // Mute compiler.
+ JNI_END
+ 
+ 
+-- 
+2.18.0
+