RFR: JDK-8129395 Configure should verify that -fstack-protector is valid - take 2

[Erik Joelsson]

Change looks good.
/Erik

On 2016-02-05 11:48, Magnus Ihse Bursie wrote:
> A previous fix to check if -fstack-protector is accepted by gcc 
> failed, since when testing the option, gcc emitted a warning and not 
> an error.
>
> The one thing I'm thinking here about is if the ssp-buffer-size option 
> should be more tightly coupled with the -fstack-protector flag. It 
> does not harm to have it without the -f flag, but it seems a bit 
> funny. Opinions?
>
> I also noted that this flag is added to CFLAGS_DEBUG_OPTIONS. This 
> means that it only gets activated if we generate debug symbols. For 
> Oracle builds we always do so it doesn't really matter, but I'd say 
> that it's technically incorrect. I'd rather not fix that now, though, 
> but save it for the upcoming and long overdue cleanup of flags handling.
>
> Bug: https://bugs.openjdk.java.net/browse/JDK-8129395
> Patch inline:
> diff --git a/common/autoconf/flags.m4 b/common/autoconf/flags.m4
> --- a/common/autoconf/flags.m4
> +++ b/common/autoconf/flags.m4
> @@ -1,5 +1,5 @@
>  #
> -# Copyright (c) 2011, 2015, Oracle and/or its affiliates. All rights 
> reserved.
> +# Copyright (c) 2011, 2016, Oracle and/or its affiliates. All rights 
> reserved.
>  # DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
>  #
>  # This code is free software; you can redistribute it and/or modify it
> @@ -426,7 +426,7 @@
>        # Add runtime stack smashing and undefined behavior checks.
>        # Not all versions of gcc support -fstack-protector
>        STACK_PROTECTOR_CFLAG="-fstack-protector-all"
> -      FLAGS_COMPILER_CHECK_ARGUMENTS(ARGUMENT: 
> [$STACK_PROTECTOR_CFLAG], IF_FALSE: [STACK_PROTECTOR_CFLAG=""])
> +      FLAGS_COMPILER_CHECK_ARGUMENTS(ARGUMENT: 
> [$STACK_PROTECTOR_CFLAG -Werror], IF_FALSE: [STACK_PROTECTOR_CFLAG=""])
>
>        CFLAGS_DEBUG_OPTIONS="$STACK_PROTECTOR_CFLAG --param 
> ssp-buffer-size=1"
>        CXXFLAGS_DEBUG_OPTIONS="$STACK_PROTECTOR_CFLAG --param 
> ssp-buffer-size=1"
>
> /Magnus