llvm dev - Mar 2006 - [LLVMdev] Re: Re: Re: New GCC4-based C/C++/ObjC front-end for LLVM

Chris Lattner wrote:
> On Thu, 2 Mar 2006, Chris Lattner wrote:
>>> Any ideas what could be wrong?
>>
>> Sorry for the delay, please try this tarball:
>> http://nondot.org/sabre/2006-03-02-llvm-gcc-4.tar.gz
> 
> Actually, do to a recent change in CVS, this tarball will probably not
> work anymore.  Please apply the attached (small) patch on top of it in
> the gcc directory.
> 
> Worth noting, this front-end only works with LLVM mainline, not LLVM 1.6.
Without the patch, I get this:


  TreeToLLVM::StartFunctionBody()':
../../2006-03-02-llvm-gcc-4/gcc/llvm-convert.cpp:344: warning: statement
with
   no effect
../../2006-03-02-llvm-gcc-4/gcc/llvm-convert.cpp: At global scope:
../../2006-03-02-llvm-gcc-4/gcc/llvm-convert.cpp:1305: error: parse error
   before `__attribute__'
../../2006-03-02-llvm-gcc-4/gcc/llvm-convert.cpp: In function `tree_node*
   StripLLVMTranslationFn(...)':
../../2006-03-02-llvm-gcc-4/gcc/llvm-convert.cpp:1312: error: `I' undeclared
   (first use this function)
../../2006-03-02-llvm-gcc-4/gcc/llvm-convert.cpp:1312: error: (Each
undeclared
   identifier is reported only once for each function it appears in.)
../../2006-03-02-llvm-gcc-4/gcc/llvm-convert.cpp:1312: error: ISO C++
forbids
   declaration of `tsi_next' with no type
../../2006-03-02-llvm-gcc-4/gcc/llvm-convert.cpp:1312: error: `int tsi_next'


With the patch, I get exactly the same error. The configure command was:

../2006-03-02-llvm-gcc-4/configure --enable-languages=c,c++
--enable-llvm=/space/p2/ghost/build/llvm-cvs/install --prefix=`pwd`/install
--program-prefix=llvm-                                        

and my LLVM is CVS state as of Friday.

Any suggestions?

- Volodya

On Mon, 6 Mar 2006, Vladimir Prus wrote:
> ../../2006-03-02-llvm-gcc-4/gcc/llvm-convert.cpp:1305: error: parse 
error
>   before `__attribute__'
Can you send me the preprocessed .i file for this file?

To work around the above error, just remove "ATTRIBUTE_UNUSED" from
that
line.
> ../../2006-03-02-llvm-gcc-4/gcc/llvm-convert.cpp: In function `tree_node*
>   StripLLVMTranslationFn(...)':
> ../../2006-03-02-llvm-gcc-4/gcc/llvm-convert.cpp:1312: error: `I'
undeclared
>   (first use this function)
> ../../2006-03-02-llvm-gcc-4/gcc/llvm-convert.cpp:1312: error: (Each
> undeclared
>   identifier is reported only once for each function it appears in.)
> ../../2006-03-02-llvm-gcc-4/gcc/llvm-convert.cpp:1312: error: ISO C++
> forbids
>   declaration of `tsi_next' with no type
> ../../2006-03-02-llvm-gcc-4/gcc/llvm-convert.cpp:1312: error: `int
tsi_next'
This is more strange.  The code likes this for me:

     for (tree_stmt_iterator I = tsi_start(node); !tsi_end_p(I);
tsi_next(&I))
       if (TREE_CODE(tsi_stmt(I)) == LABEL_EXPR)
         SET_DECL_LLVM(TREE_OPERAND(tsi_stmt(I), 0), 0);

Is this what you have?  If so, can you send me the preprocessed source 
file?  What host compiler are you using?

-Chris

-- 
http://nondot.org/sabre/
http://llvm.org/

Chris Lattner wrote:
> On Mon, 6 Mar 2006, Vladimir Prus wrote:
>> ../../2006-03-02-llvm-gcc-4/gcc/llvm-convert.cpp:1305: error: parse
> error
>>   before `__attribute__'
> 
> Can you send me the preprocessed .i file for this file?
Sure, I've sent it by private email (180K is too big for list).
> To work around the above error, just remove "ATTRIBUTE_UNUSED"
from that
> line.
Ok, done.
>> ../../2006-03-02-llvm-gcc-4/gcc/llvm-convert.cpp: In function
`tree_node*
>>   StripLLVMTranslationFn(...)':
>> ../../2006-03-02-llvm-gcc-4/gcc/llvm-convert.cpp:1312: error: `I'
>> undeclared
>>   (first use this function)
>> ../../2006-03-02-llvm-gcc-4/gcc/llvm-convert.cpp:1312: error: (Each
>> undeclared
>>   identifier is reported only once for each function it appears in.)
>> ../../2006-03-02-llvm-gcc-4/gcc/llvm-convert.cpp:1312: error: ISO C++
>> forbids
>>   declaration of `tsi_next' with no type
>> ../../2006-03-02-llvm-gcc-4/gcc/llvm-convert.cpp:1312: error: `int
>> tsi_next'
> 
> This is more strange.  The code likes this for me:
> 
>      for (tree_stmt_iterator I = tsi_start(node); !tsi_end_p(I);
>      tsi_next(&I))
>        if (TREE_CODE(tsi_stmt(I)) == LABEL_EXPR)
>          SET_DECL_LLVM(TREE_OPERAND(tsi_stmt(I), 0), 0);
> 
> Is this what you have?  
Yes, but after removing ATTRIBUTE_UNUSED the second error is gone. <rumbling
about syntax errors recovery quality in gcc.../>
> What host compiler are you using?
  gcc version 3.3.5 (Debian 1:3.3.5-13)

Should handle attributes just fine, I think. Ah, I know the problem. The
compile fails with:

    void  *data ATTRIBUTE_UNUSED) {

but works with:

    void ATTRIBUTE_UNUSED *data) {

and with:

    ATTRIBUTE_UNUSED void *data) {


IIRC, gcc used to be picky about placements of attributes. Any change you'll
change to any of working syntaxes, or, you 100% portable approach of:

    void*  /* data */) {


Thanks,
Volodya