[racket-dev] Compilation of 5.3.2 fails on some compilers

Thanks for the detailed explanation. It's a lot clearer now why it's  
needed.

But i figured out that the real culprit was cross-compilation in  
combination with autoconf. autoconfs default rule for test results when  
running cross-compilation was set to noinline not available, and therefore  
setting the define to expand to nothing.
It should be, in this case and for inline too, enough to check for  
compilation, not for running the test. If the attribute is not supported  
the compilation should already fail.
I attached a patch to change these two test and fix a typo. Compilation  
runs without any errors then.

While checking for more similar tests i noticed that the test for  
compare-and-swap is completely screwed up. Even on a modern Core i7 with  
gcc 4.x it fails with default settings on a 32bit OS. The CAS builtins  
need at least -march=i686 there to run, otherwise you get undefined symbol  
errors. That never happens on 64bit OS because gcc knows that every x86-64  
processor has CAS operations. I think it would be a good choice to set  
-march when using gcc with 32bit OS, assuming at least a pentium pro  
processor might be ok nowadays. It must be remain unset for 64bit, or gcc  
throws errors. Unfortunately my autoconf skills are far too limited to  
provide a patch.

Tobias



On Fri, 01 Feb 2013 19:30:15 +0100, Matthew Flatt <mflatt at cs.utah.edu>  
wrote:

> At Fri, 1 Feb 2013 12:23:59 +0100, Tobias Hammer wrote:
>> i am getting the following error when i try to compile racket-textual  
>> on a
>> a version of gcc that does not support the 'noinline' attribute:
>>
>> xsrc/place.c: In function 'place_start_proc':
>> xsrc/place.c:2793: warning: assignment makes pointer from integer  
>> without
>> a cast
>> xsrc/place.c: At top level:
>> xsrc/place.c:3185: error: conflicting types for
>> 'place_start_proc_after_stack'
>> xsrc/place.c:2793: note: previous implicit declaration of
>> 'place_start_proc_after_stack' was here
>>
>> The cause is that the forward declaration of
>> 'place_start_proc_after_stack' is missing. It was originally there (L  
>> 95)
>> but the MZ_DO_NOT_INLINE macro expands to nothing, effectively removing
>> the declaration.
>>
>> The wrapping macro was added in commit 9692765e2 but the commit message
>> gives no real reason why it is needed. I am a bit worried to revert the
>> change because i don't know which bug i could reintroduce. What would be
>> the correct fix to compile 5.3.2?
>
> Hopefully, the right fix is to make `MZ_DO_NOT_INLINE(decl)' expand to
> `decl' if no "no inline" annotation is available.
>
> If place_start_proc_after_stack() is inlined at its only use, whcih is
> in place_start_proc(), then a new place will not register its stack
> bounds correctly for the implementation of continuations. The
> implementation of continuations assumes that local variables in
> place_start_proc_after_stack() are shallower on the stack than
> variables in place_start_proc(), and inlining can defeat that
> assumption.
>
> If there's no way to say "no inlining" and inlining of that function
> can still happen, then we'll have to work harder to confuse the C
> compiler. The same is true for any other use of MZ_DO_NOT_INLINE().
>
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