llvm dev - Feb 2008 - [LLVMdev] strange visibility error when compiling llvm-gcc-4.2

On Feb 6, 2008, at 5:18 AM, Duncan Sands wrote:
> Hi,
>
>> if /bin/sh ./libtool --mode=compile /s/llvm/obj.gcc42/./gcc/xgcc -B/ 
>> s/llvm/obj.gcc42/./gcc/ -B/usr/local/i686-pc-linux-gnu/bin/ -B/usr/ 
>> local/i686-pc-linux-gnu/lib/ -isystem /usr/local/i686-pc-linux-gnu/ 
>> include -isystem /usr/local/i686-pc-linux-gnu/sys-include - 
>> DHAVE_CONFIG_H -I. -I/s/llvm/svn.gcc42/libgomp -I.  -I/s/llvm/ 
>> svn.gcc42/libgomp/config/linux/x86 -I/s/llvm/svn.gcc42/libgomp/ 
>> config/linux -I/s/llvm/svn.gcc42/libgomp/config/posix -I/s/llvm/ 
>> svn.gcc42/libgomp  -Wall -Werror -ftls-model=initial-exec - 
>> march=i486 -mtune=i686 -Wc,-pthread -O2 -g -O2  -MT lock.lo -MD -MP  
>> -MF ".deps/lock.Tpo" -c -o lock.lo
/s/llvm/svn.gcc42/libgomp/config/
>> linux/lock.c; \
>>        then mv -f ".deps/lock.Tpo"
".deps/lock.Plo"; else rm -f
>> ".deps/lock.Tpo"; exit 1; fi
>> yes
>> cc1: warnings being treated as errors
>> /s/llvm/svn.gcc42/libgomp/team.c:341: warning: visibility attribute  
>> not supported in this configuration; ignored
>> /s/llvm/svn.gcc42/libgomp/team.c:341: warning: visibility attribute  
>> not supported in this configuration; ignored
>> checking for tanl... make[5]: *** [team.lo] Error 1
>> ----------------------------------
>>
>> Because of the -Werror, this warning is taken as an error
>> and compilation aborts. I wonder why it warns in the first
>> place, is something broken with xgcc?
>
> I suspect this is due to the recent change by Bill (revision 46747).
Bill's change only affected darwin IIRC.  I don't know that anyone has  
built GOMP on linux yet, and OpenMP hasn't been widely tested at all.   
I'd suggest using --enable-languages=c,c++

-Chris

On 2/6/08, Chris Lattner <sabre at nondot.org>
wrote:
>
> On Feb 6, 2008, at 5:18 AM, Duncan Sands wrote:
>
> > Hi,
> >
> >> if /bin/sh ./libtool --mode=compile /s/llvm/obj.gcc42/./gcc/xgcc
-B/
> >> s/llvm/obj.gcc42/./gcc/ -B/usr/local/i686-pc-linux-gnu/bin/
-B/usr/
> >> local/i686-pc-linux-gnu/lib/ -isystem
/usr/local/i686-pc-linux-gnu/
> >> include -isystem /usr/local/i686-pc-linux-gnu/sys-include -
> >> DHAVE_CONFIG_H -I. -I/s/llvm/svn.gcc42/libgomp -I.  -I/s/llvm/
> >> svn.gcc42/libgomp/config/linux/x86 -I/s/llvm/svn.gcc42/libgomp/
> >> config/linux -I/s/llvm/svn.gcc42/libgomp/config/posix -I/s/llvm/
> >> svn.gcc42/libgomp  -Wall -Werror -ftls-model=initial-exec -
> >> march=i486 -mtune=i686 -Wc,-pthread -O2 -g -O2  -MT lock.lo -MD
-MP
> >> -MF ".deps/lock.Tpo" -c -o lock.lo
/s/llvm/svn.gcc42/libgomp/config/
> >> linux/lock.c; \
> >>        then mv -f ".deps/lock.Tpo"
".deps/lock.Plo"; else rm -f
> >> ".deps/lock.Tpo"; exit 1; fi
> >> yes
> >> cc1: warnings being treated as errors
> >> /s/llvm/svn.gcc42/libgomp/team.c:341: warning: visibility
attribute
> >> not supported in this configuration; ignored
> >> /s/llvm/svn.gcc42/libgomp/team.c:341: warning: visibility
attribute
> >> not supported in this configuration; ignored
> >> checking for tanl... make[5]: *** [team.lo] Error 1
> >> ----------------------------------
> >>
> >> Because of the -Werror, this warning is taken as an error
> >> and compilation aborts. I wonder why it warns in the first
> >> place, is something broken with xgcc?
> >
> > I suspect this is due to the recent change by Bill (revision 46747).
>
> Bill's change only affected darwin IIRC.  I don't know that anyone
has
> built GOMP on linux yet, and OpenMP hasn't been widely tested at all.
> I'd suggest using --enable-languages=c,c++
I am seeing the same errors with just building c,c++. (linux x86, also debian)

Andrew

>>
>> I suspect this is due to the recent change by Bill (revision 46747).
>
> Bill's change only affected darwin IIRC.  I don't know that anyone
has
> built GOMP on linux yet, and OpenMP hasn't been widely tested at all.
> I'd suggest using --enable-languages=c,c++
This looks like something is broken on the gcc side of things. Does a  
simple:

void
__attribute__((visibility ("hidden")))
foo()
{ }

compile with your resultant compiler?

-eric

>>> I suspect this is due to the recent change by Bill (revision
46747).
>>
>> Bill's change only affected darwin IIRC.  I don't know that
anyone
>> has
>> built GOMP on linux yet, and OpenMP hasn't been widely tested at
all.
>> I'd suggest using --enable-languages=c,c++
>
> I am seeing the same errors with just building c,c++. (linux x86,  
> also debian)
Ah, I didn't notice that Bill changed varasm.c.  Bill?

-Chris

> > > I suspect this is due to the recent change by Bill (revision
46747).
> >
> > Bill's change only affected darwin IIRC.  I don't know that
anyone has
> > built GOMP on linux yet, and OpenMP hasn't been widely tested at
all.
> > I'd suggest using --enable-languages=c,c++
> 
> I am seeing the same errors with just building c,c++. (linux x86, also
debian)
There was a change to varasm.c that was not conditioned on being on darwin:

+  /* The "make_assemble_visibility" method may issue a warning if the
visibility
+     attribute isn't supported in a configuration. This is all done through
a
+     call-back. We want to issue this same warning when needed.  */
+  if (TREE_PUBLIC (decl))
+    maybe_assemble_visibility (decl);

It seems suspicious.

Ciao,

Duncan.

On 2/6/08, Eric Christopher <echristo at apple.com>
wrote:
> >>
> >> I suspect this is due to the recent change by Bill (revision
46747).
> >
> > Bill's change only affected darwin IIRC.  I don't know that
anyone has
> > built GOMP on linux yet, and OpenMP hasn't been widely tested at
all.
> > I'd suggest using --enable-languages=c,c++
>
> This looks like something is broken on the gcc side of things. Does a
> simple:
>
> void
> __attribute__((visibility ("hidden")))
> foo()
> { }
>
> compile with your resultant compiler?
; ModuleID = 'foo.c'
target datalayout
"e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:32:32"
target triple = "i686-pc-linux-gnu"

define hidden void @foo() {
entry:
        br label %return

return:         ; preds = %entry
        ret void
}

also works when going to native .o or bytecode.

llvm-gcc -v
Using built-in specs.
Target: i686-pc-linux-gnu
Configured with: ../source/configure
--prefix=/home/andrewl/Research/cfe-4.2/install
--enable-llvm=/home/andrewl/Research/llvm --enable-languages=c,c++
--disable-bootstrap --disable-shared --disable-werror
Thread model: posix
gcc version 4.2.1 (Based on Apple Inc. build 5546) (LLVM build)

> > Bill's change only affected darwin IIRC.  I don't know that
anyone has
> > built GOMP on linux yet, and OpenMP hasn't been widely tested at
all.
> > I'd suggest using --enable-languages=c,c++
> 
> I am seeing the same errors with just building c,c++. (linux x86, also
debian)
This bit of Bill's patch did it:

-#ifdef HAVE_GAS_HIDDEN
+
+#if !defined(ENABLE_LLVM) && defined(HAVE_GAS_HIDDEN)
  fprintf (asm_out_file, "\t.%s\t", type);
  assemble_name (asm_out_file, name);
  fprintf (asm_out_file, "\n");
#else
  warning (OPT_Wattributes, "visibility attribute not supported "
           "in this configuration; ignored");
#endif