From 732aab80cb1505ef2f4d8a6e141f835aa9f6d985 Mon Sep 17 00:00:00 2001
From: Abdur Rehman <abdur_rehman@mentor.com>
Date: Mon, 24 Oct 2016 20:24:32 +0500
Subject: [PATCH] icedtea flags to compile with GCC 6

Upstream bug filed here:
https://bugs.openjdk.java.net/browse/JDK-8163032

This patch combines the changes introduced by following commits:
* http://hg.openjdk.java.net/jdk7u/jdk7u/hotspot/rev/e34324d73cd5
* http://hg.openjdk.java.net/jdk7u/jdk7u/jdk/rev/9e1264f51bae

Upstream-Status: Backport

Signed-off-by: Abdur Rehman <abdur_rehman@mentor.com>
---
 openjdk/hotspot/make/linux/makefiles/gcc.make | 7 +++++++
 openjdk/jdk/make/common/Defs-linux.gmk        | 8 +++++++-
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git openjdk/hotspot/make/linux/makefiles/gcc.make openjdk/hotspot/make/linux/makefiles/gcc.make
index 4ef0e49..bca3c5c 100644
--- openjdk/hotspot/make/linux/makefiles/gcc.make
+++ openjdk/hotspot/make/linux/makefiles/gcc.make
@@ -83,6 +83,7 @@ ifeq ($(TYPE),SHARK)
 CFLAGS += $(LIBFFI_CFLAGS)
 CFLAGS += $(LLVM_CFLAGS)
 endif
+CFLAGS += -std=gnu++98
 CFLAGS += $(VM_PICFLAG)
 CFLAGS += -fno-rtti
 CFLAGS += -fno-exceptions
@@ -93,6 +94,12 @@ CFLAGS += -fcheck-new
 ifneq "$(shell expr \( $(CC_VER_MAJOR) \> 4 \) \| \( \( $(CC_VER_MAJOR) = 4 \) \& \( $(CC_VER_MINOR) \>= 3 \) \))" "0"
 CFLAGS += -fvisibility=hidden
 endif
+# GCC 6 has more aggressive dead-store elimination which causes the VM to crash
+# It also optimises away null pointer checks which are still needed.
+# We turn both of these optimisations off.
+ifneq "$(shell expr \( $(CC_VER_MAJOR) \>= 6 \))" "0"
+CFLAGS += -fno-delete-null-pointer-checks -fno-lifetime-dse
+endif
 
 ARCHFLAG = $(ARCHFLAG/$(BUILDARCH))
 ARCHFLAG/i486    = -m32 -march=i586
diff --git openjdk/jdk/make/common/Defs-linux.gmk openjdk/jdk/make/common/Defs-linux.gmk
index f64042c..727593c 100644
--- openjdk/jdk/make/common/Defs-linux.gmk
+++ openjdk/jdk/make/common/Defs-linux.gmk
@@ -217,6 +217,12 @@ CFLAGS_REQUIRED_ppc64   += -fno-tree-vectorize
   CFLAGS_REQUIRED       =  $(CFLAGS_REQUIRED_$(ARCH))
   LDFLAGS_COMMON        += $(LDFLAGS_COMMON_$(ARCH))
 endif
+# GCC 6 has more aggressive dead-store elimination which causes the VM to crash
+# It also optimises away null pointer checks which are still needed.
+# We turn both of these optimisations off.
+ifeq ($(shell $(EXPR) $(CC_MAJORVER) \>= 6 ),1)
+ CFLAGS_REQUIRED += -fno-delete-null-pointer-checks -fno-lifetime-dse
+endif
 
 # If this is a --hash-style=gnu system, use --hash-style=both
 #   The gnu .hash section won't work on some Linux systems like SuSE 10.
@@ -281,7 +287,7 @@ CFLAGS_OPT      = $(CC_OPT)
 CFLAGS_DBG      = $(DEBUG_FLAG)
 CFLAGS_COMMON += $(CFLAGS_REQUIRED)
 
-CXXFLAGS_COMMON = $(GLOBAL_KPIC) -DCC_NOEX $(GCC_WARNINGS)
+CXXFLAGS_COMMON = -std=gnu++98 $(GLOBAL_KPIC) -DCC_NOEX $(GCC_WARNINGS)
 CXXFLAGS_OPT	= $(CC_OPT)
 CXXFLAGS_DBG	= $(DEBUG_FLAG)
 CXXFLAGS_COMMON += $(CFLAGS_REQUIRED)
-- 
2.8.1