RFR: 8186780: clang-4.0 fastdebug assertion failure in os_linux_x86:os::verify_stack_alignment()

[Martin Buchholz]

Thanks Erik.

On Wed, Jun 20, 2018 at 4:19 PM, Erik Joelsson <erik.joelsson at oracle.com>
wrote:

> Hello,
>
> It's very probable that we have made several such mistakes with our flags,
> since for the most part, we have a 1-1 mapping of compiler and OS. We
> certainly appreciate correcting this whenever possible. I don't have the
> expertise to verify your claim here, but I will take your word for it.
>
> The change looks ok, but there is already a big block of clang specific
> stuff close by. Perhaps move this assignment there?


Yes, that does look like a better place:

 --- a/make/autoconf/flags-cflags.m4
+++ b/make/autoconf/flags-cflags.m4
@@ -470,14 +470,6 @@ AC_DEFUN([FLAGS_SETUP_CFLAGS_HELPER],
     # COMMON to gcc and clang
     TOOLCHAIN_CFLAGS_JVM="-pipe -fno-rtti -fno-exceptions \
         -fvisibility=hidden -fno-strict-aliasing -fno-omit-frame-pointer"
-
-    if test "x$TOOLCHAIN_TYPE" = xclang; then
-      # In principle the stack alignment below is cpu- and ABI-dependent
and
-      # should agree with values of StackAlignmentInBytes in various
-      # src/hotspot/cpu/*/globalDefinitions_*.hpp files, but this value
-      # currently works for all platforms.
-      TOOLCHAIN_CFLAGS_JVM="$TOOLCHAIN_CFLAGS_JVM
-mno-omit-leaf-frame-pointer -mstack-alignment=16"
-    fi
   fi

   if test "x$TOOLCHAIN_TYPE" = xgcc; then
@@ -499,6 +491,12 @@ AC_DEFUN([FLAGS_SETUP_CFLAGS_HELPER],
     # (see http://llvm.org/bugs/show_bug.cgi?id=7554)
     TOOLCHAIN_CFLAGS_JVM="$TOOLCHAIN_CFLAGS_JVM -flimit-debug-info"

+    # In principle the stack alignment below is cpu- and ABI-dependent and
+    # should agree with values of StackAlignmentInBytes in various
+    # src/hotspot/cpu/*/globalDefinitions_*.hpp files, but this value
+    # currently works for all platforms.
+    TOOLCHAIN_CFLAGS_JVM="$TOOLCHAIN_CFLAGS_JVM
-mno-omit-leaf-frame-pointer -mstack-alignment=16"
+
     if test "x$OPENJDK_TARGET_OS" = xlinux; then
       TOOLCHAIN_CFLAGS_JDK="-pipe"
       TOOLCHAIN_CFLAGS_JDK_CONLY="-fno-strict-aliasing" # technically NOT
for CXX