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, 42 insertions, 0 deletions

diff --git a/recipes-core/openjdk/patches-openjdk-8/0014-hotspot-zero-fix-undefined-behaviour-gcc-v8-fix.patch b/recipes-core/openjdk/patches-openjdk-8/0014-hotspot-zero-fix-undefined-behaviour-gcc-v8-fix.patch
new file mode 100644
index 0000000..467a1cd
--- /dev/null
+++ b/recipes-core/openjdk/patches-openjdk-8/0014-hotspot-zero-fix-undefined-behaviour-gcc-v8-fix.patch
@@ -0,0 +1,42 @@
+From 3bd88f93a90876f8ead05de40816da0bd1e39aac Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Andr=C3=A9=20Draszik?= <andre.draszik@jci.com>
+Date: Mon, 13 Aug 2018 11:49:26 +0100
+Subject: [PATCH] hotspot/zero: fix undefined behaviour (gcc v8 fix)
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+Backport patch from
+  https://bugs.openjdk.java.net/browse/JDK-8202600
+  http://hg.openjdk.java.net/jdk8u/jdk8u/hotspot/rev/ca4663e58916
+to address segfaults due to undefined behaviour.
+
+|# HG changeset patch
+|# User sgehwolf
+|# Date 1525366788 -7200
+|# Node ID ca4663e589160509d6aef8ec890815e1330b97bc
+|# Parent  a27880c1288ba776f65748b68c198df97427f950
+8202600: [Zero] Undefined behaviour in src/os_cpu/linux_zero/vm/os_linux_zero.cpp
+Reviewed-by: stuefe, shade, dholmes
+
+Signed-off-by: André Draszik <andre.draszik@jci.com>
+Upstream-Status: Backport [http://hg.openjdk.java.net/jdk8u/jdk8u/hotspot/rev/ca4663e58916]
+---
+ hotspot/src/os_cpu/linux_zero/vm/os_linux_zero.cpp | 1 +
+ 1 file changed, 1 insertion(+)
+
+diff --git a/hotspot/src/os_cpu/linux_zero/vm/os_linux_zero.cpp b/hotspot/src/os_cpu/linux_zero/vm/os_linux_zero.cpp
+index 1d069c6d..8dcf9d44 100644
+--- a/hotspot/src/os_cpu/linux_zero/vm/os_linux_zero.cpp
++++ b/hotspot/src/os_cpu/linux_zero/vm/os_linux_zero.cpp
+@@ -408,6 +408,7 @@ void os::print_register_info(outputStream *st, void *context) {
+ 
+ extern "C" {
+   int SpinPause() {
++    return 0; // Shouldn't matter.
+   }
+ 
+ 
+-- 
+2.18.0
+