[2.3 BRANCH]: gstabs issue

[Andrew Hughes]

----- Original Message -----
> On 08/06/2012 02:42 PM, Andrew Hughes wrote:
> > There was a regression with DEBUG_BINARIES which resulted in some
> > architectures
> > (x86, SPARC, etc.) producing STABS debug information rather than
> > DWARF.
> > 
> > The fix for this is now in OpenJDK8 and IcedTea7 HEAD:
> > 
> > http://hg.openjdk.java.net/icedtea/jdk7/hotspot/rev/c5430c659d54
> > 
> > Ok to backport this to the 2.3 forest?
> 
> It's very hard to understand what is supposed to be happening.  I
> think
> it means that ia64, amd64, arm, ppc get DWARF debug info, but x86/32
> and others get STABS.  But this makes no sense at all: STABS is not
> appropriate for x86/32 or any other Linux target AFAIAA.
> 

No, that's what's happening now without this patch.  This patch corrects the behaviour so that
DEBUG_BINARIES again takes precedence and applies "-g" in all cases (no "-gstabs")
whatever the architecture or build type (fastdebug/debug/product).  It's hard to
see because the patch is moving the previous lines inside an else block, which is only
evaluated if DEBUG_BINARIES is not equal to true.

+# DEBUG_BINARIES uses full -g debug information for all configs
+ifeq ($(DEBUG_BINARIES), true)
+ CFLAGS += -g
+else
<< previous behaviour >>
endif

The discussion is here:

http://mail.openjdk.java.net/pipermail/hotspot-dev/2012-July/006247.html

It's a bit more involved than our patch, but makes the final file clearer -- one route
if DEBUG_BINARIES is set, another if it isn't -- and hopefully reduces the risk that Oracle
will turn on unwanted debug options for us again :-)

Final version post-patch:

http://hg.openjdk.java.net/icedtea/jdk7/hotspot/file/tip/make/linux/makefiles/gcc.make

> Andrew.
> 
> 

-- 
Andrew :)

Free Java Software Engineer
Red Hat, Inc. (http://www.redhat.com)

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