[Stackless] Problem building release27-maint in 64-bit linux.

[Jeff Senn]

As I'm responsible for that patch -- I'll simply say that IIRC no one was sure that it was working at all on 64-bit
Linux at the time...and I didn't have a 64 bit linux system to test (there's probably a discussion on the list, or I can dig up email if
anyone cares...)

In any case, I'd be happy if someone who understands this deeply made the right changes to the
configure scripts to make this more flexible.  Historically the correct registers to save
have depended on OS, architecture, *and* (sometimes) compiler version.

As you suggest, some strategy to choose the registers more specifically at configure time is probably a good 
idea.

On Jul 11, 2011, at 11:39 AM, Anselm Kruis wrote:

> Hi,
> 
> I can confirm the problem report for gcc. Analysis shows, that problem "./Stackless/core/slp_transfer.c:153:1: error: bp cannot be used in asm here" was introduced by the backport of change r83165 to release27-maint (r88294). See below for the diff.
> 
> The problem is caused by configure.in:
> -------8<------------8<-------------
> # Stackless flags for compiling the hard switching code
> case $MACHDEP in
>        darwin)
>                SLPFLAGS="-fomit-frame-pointer -O2"
>                ;;
>        *)
>                SLPFLAGS="-fno-omit-frame-pointer -O2"
>                ;;
> esac
> AC_SUBST(SLPFLAGS)
> -------8<------------8<-------------
> 
> For Linux and all other non darwin systems, SLPFLAGS is "-fno-omit-frame-pointer -O2" and therefore the code does not compile. (SLPFLAGS was introduced with change r82398.)
> 
> How to fix this problem?
> 
> If I understand the commit comment correctly, there were crashes on OS-X. But what about Linux? I'm not aware of problems on Linux amd64. Can we make the longer REGS_TO_SAVE list a conditional define? Something like:
> 
> #ifdef SLP_SAVE_FRAME_POINTER
> +#define REGS_TO_SAVE "rdx", "rbx", "r12", "r13", "r14", "r15", "r9", "r8", "rdi", "rsi", "rcx", "rbp"
> #else
> +#define REGS_TO_SAVE "rdx", "rbx", "r12", "r13", "r14", "r15", "r9", "r8", "rdi", "rsi", "rcx"
> #endif
> 
> and define SLP_SAVE_FRAME_POINTER in configure.in together with -fomit-frame-pointer.
> 
> 
> Just for reference: the change, that introduced the problem:
> 
> $ svn log -c 83165 http://svn.python.org/projects/stackless/trunk/Stackless/platf/switch_amd64_unix.h | less
> ------------------------------------------------------------------------
> r83165 | jeff.senn | 2010-07-26 16:34:04 +0200 (Mon, 26 Jul 2010) | 3 lines
> 
> Added saved registers. Doesn't crash on tests anymore on OS-X 10.6 (gcc-4.2.1)
> Not sure registers are minimal. Not sure will work on other platforms/compilers.  But since the consensus is that it has never worked, committing as incremental progress.
> 
> ------------------------------------------------------------------------
> 
> 
> $ svn diff -c 83165 http://svn.python.org/projects/stackless/trunk/Stackless/platf/switch_amd64_unix.h | less
> Index: switch_amd64_unix.h
> ===================================================================
> --- switch_amd64_unix.h (revision 83164)
> +++ switch_amd64_unix.h (revision 83165)
> @@ -29,8 +35,8 @@
> /* the above works fine with gcc 2.96, but 2.95.3 wants this */
> #define STACK_MAGIC 0
> 
> -#define REGS_TO_SAVE "rdx", "rbx", "r12", "r13", "r14", "r15"
> 
> +#define REGS_TO_SAVE "rdx", "rbx", "r12", "r13", "r14", "r15", "r9", "r8", "rdi", "rsi", "rcx", "rbp"
> 
> static int
> slp_switch(void)
> 
> 
> 
> Regards
>   Anselm
> 
> 
> 
> 
> Am 07.05.2011 00:48, schrieb Richard Tew:
>> On Fri, May 6, 2011 at 11:27 PM, Estevo<euccastro at yahoo.com>  wrote:
>> 
>>> I got the following error trying to make release27-maint in a 64-bit
>>> 
>> 
>> Presumably there's a change that on your system engages
>> -fno-omit-frame-pointer when to compile Stackless we need
>> -fomit-frame-pointer.
>> 
>> Anyone care to look into this? :-)  We could use a patch.
>> 
>> Cheers,
>> Richard.
>> 
>> 
>> 
>> 
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> 
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