Re: PING^2 Re: PATCH: fix collect2 handling of --demangle and --no-demangle

["H.J. Lu" <hjl.tools@gmail.com>]

On Sun, Jul 24, 2011 at 7:03 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Mon, Jul 11, 2011 at 10:45 AM, Sandra Loosemore
> <sandra@codesourcery.com> wrote:
>> Ping?
>>
>> http://gcc.gnu.org/ml/gcc-patches/2011-06/msg01368.html
>>
>>> We had a bug report from a customer that the linker was ignoring the
>>> --demangle and --no-demangle options when generating map files.
>>> Moreover, it was failing in a host-dependent way; on Windows hosts,
>>> it was always emitting demangled names in the map file, while on
>>> Linux hosts, it never did.  Moreover, on Windows hosts it also
>>> ignored the setting of the COLLECT_NO_DEMANGLE environment variable.
>>>
>>> This turns out to be a problem in collect2, or actually, three
>>> problems:
>>>
>>> (1) By default, collect2 is configured to filter out --demangle and
>>> --no-demangle from the linker options, and it tries to do demangling
>>> on symbol names in stdout and stderr itself instead.  But, it is too
>>> stupid to know about the map file.
>>>
>>> (2) Collect2 is trying to set COLLECT_NO_DEMANGLE to disable
>>> demangling in ld, but in a nonportable way that causes it to be
>>> always unset instead on Windows.
>>>
>>> (3) If you configure with --with-demangler-in-ld to try to disable
>>> the collect2 demangling, there's another bug that causes it to ignore
>>> any explicit --demangle or --no-demangle options and only pay
>>> attention to whether or not COLLECT_NO_DEMANGLE is set.
>>>
>>> The attached patch addresses all three problems:
>>>
>>> (1) I've flipped the default to --with-demangler-in-ld=yes.  Note
>>> that configure.ac already takes care not to let this percolate
>>> through to collect2 without verifying that the linker is GNU ld and
>>> that it is a version that supports --demangle.  Perhaps back in 2004
>>> when this option was first added, the ld demangling support was
>>> deemed too experimental to make it the default, but that's surely not
>>> the case any more.  Also, since this has been broken since 2004, I'm
>>> not sure there's much reason to be concerned with backwards
>>> compatibility, here....
>>>
>>> (2) I fixed the COLLECT_NO_DEMANGLE environment variable setting
>>> recipe.
>>>
>>> (3) I simplified the argument processing for --demangle and
>>> --no-demangle to pass them straight through to the linker when
>>> HAVE_LD_DEMANGLE is defined.
>>>
>>> OK to commit?
>>>
>>> -Sandra
>>>
>>> 2011-06-17  Sandra Loosemore  <sandra@codesourcery.com>
>>>
>>>    gcc/
>>>    * configure.ac (demangler_in_ld): Default to yes.
>>>    * configure: Regenerated.
>>>    * collect2.c (main): When HAVE_LD_DEMANGLE is defined, don't
>>>    mess with COLLECT_NO_DEMANGLE, and just pass --demangle and
>>>    --no-demangle options straight through to ld.  When
>>>    HAVE_LD_DEMANGLE is not defined, set COLLECT_NO_DEMANGLE in a
>>>    way that has the intended effect on Windows.
>
> It caused:
>
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49835
>

I checked in this as an obvious fix.


-- 
H.J.
---
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 207b097..70cac5b 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2011-07-24  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR bootstrap/49835
+	* collect2.c (demangle_flag): Removed.
+
 2011-07-24  Sandra Loosemore  <sandra@codesourcery.com>

 	* configure.ac (demangler_in_ld): Default to yes.
diff --git a/gcc/collect2.c b/gcc/collect2.c
index cd0fad7..cf39693 100644
--- a/gcc/collect2.c
+++ b/gcc/collect2.c
@@ -179,7 +179,6 @@ struct head
 bool vflag;				/* true if -v or --version */
 static int rflag;			/* true if -r */
 static int strip_flag;			/* true if -s */
-static const char *demangle_flag;
 #ifdef COLLECT_EXPORT_LIST
 static int export_flag;                 /* true if -bE */
 static int aix64_flag;			/* true if -b64 */