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digitalmars.D - GDC 11.3/12.1 -m32: Illegal instruction (core dumped) [SSE, Pentium

reply kdevel <kdevel vogtner.de> writes:
After I encountered illegal instruction signals whith 
dmd-generated code [1] I eventually bootstrapped GDC 11.3 and 
12.1. Unfortunately the problem persists. A statically linked 
program receives SIGILL, as gdb says this happens here:

```
(gdb) bt






(gdb) disass
Dump of assembler code for function 
_D2rt5minfo11ModuleGroup6__ctorMFNbNcNiAyPS6object10ModuleInfoZSQCkQCkQCh:
    0x080b7e80 <+0>:	mov    0x4(%esp),%eax
    0x080b7e84 <+4>:	movq   0x8(%esp),%xmm0
=> 0x080b7e8a <+10>:	movq   %xmm0,(%eax)
    0x080b7e8e <+14>:	ret
```

I have checked the build log: The D runtime has been compiled 
with `-m32`. According to GCC's documentation [2] the option 
`-m32` means “The -m32 option [...] generates code that runs on 
any i386 system.” Obviously this is not the case:

```
module structtest;

struct MyStruct {
    int [] i;
    this (int [] i)
    {
       this.i = i;
    }
}
```

compiling with `gdc -m32 -O2 -c` and inspecting the generated 
code with `objdump` gives this:

```
[...]
Disassembly of section .text.ref structtest.MyStruct 
structtest.MyStruct.__ctor(int[]):

00000000 <ref structtest.MyStruct 
structtest.MyStruct.__ctor(int[])>:
    0:   8b 44 24 04             mov    0x4(%esp),%eax
    4:   f3 0f 7e 44 24 08       movq   0x8(%esp),%xmm0
    a:   66 0f d6 00             movq   %xmm0,(%eax)
    e:   c3                      ret
[...]
```

Compiling with `gdc -m32 -march=pentium3 -O2 -c` generated the 
expected code:
```
00000080 <ref structtest.MyStruct 
structtest.MyStruct.__ctor(int[])>:
   80:   8b 44 24 04             mov    0x4(%esp),%eax
   84:   8b 54 24 08             mov    0x8(%esp),%edx
   88:   8b 4c 24 0c             mov    0xc(%esp),%ecx
   8c:   89 10                   mov    %edx,(%eax)
   8e:   89 48 04                mov    %ecx,0x4(%eax)
   91:   c3                      ret
```

But this does of course not change the code which is already 
compiled into  libgphobos.a ...

[1] 
http://forum.dlang.org/thread/suwlbzlgqdylfauwgteu forum.dlang.org
DMD 2.090.1: SIGILL, Illegal instruction on (ahem) intel Pentium 
III
[2] https://gcc.gnu.org/onlinedocs/gcc/x86-Options.html
May 12 2022
next sibling parent reply rikki cattermole <rikki cattermole.co.nz> writes:
On 13/05/2022 3:33 PM, kdevel wrote:

 I have checked the build log: The D runtime has been compiled with 
 `-m32`. According to GCC's documentation [2] the option `-m32` means 
 “The -m32 option [...] generates code that runs on any i386 system.” 
 Obviously this is not the case:


Newer x86 machines have the SSE2 extension.

Which was first introduced on Pentium 4's and has been in place on 
pretty much all x86 chips since 2003. So emitting it as a default is fine.

Unfortunately I think you're stuck building your own runtime (and 
possibly compiler) if you want D to run on such an old cpu like this 
(said by someone who has a P3 and a P4 sitting beside me).
May 12 2022
parent reply kdevel <kdevel vogtner.de> writes:
On Friday, 13 May 2022 at 04:13:44 UTC, rikki cattermole wrote:
[...]

 Unfortunately I think you're stuck building your own runtime 
 (and possibly compiler) if you want D to run on such an old cpu 
 like this (said by someone who has a P3 and a P4 sitting beside 
 me).


I am rebuilding GCC with --with-arch_32=pentium3 now [3].

[3] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95661
     Bug 95661 - Code built with -m32 uses SSE2 instructions
May 12 2022
next sibling parent reply Iain Buclaw <ibuclaw gdcproject.org> writes:
On Friday, 13 May 2022 at 05:56:23 UTC, kdevel wrote:

 On Friday, 13 May 2022 at 04:13:44 UTC, rikki cattermole wrote:
 [...]

 Unfortunately I think you're stuck building your own runtime 
 (and possibly compiler) if you want D to run on such an old 
 cpu like this (said by someone who has a P3 and a P4 sitting 
 beside me).


 I am rebuilding GCC with --with-arch_32=pentium3 now [3].

 [3] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95661
     Bug 95661 - Code built with -m32 uses SSE2 instructions


Reminds me of another GCC bug I encountered on Solaris/Pentium4 
that appears to have been introduced around the 10.x development 
as well.

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103015
May 13 2022
parent kdevel <kdevel vogtner.de> writes:
On Friday, 13 May 2022 at 09:22:40 UTC, Iain Buclaw wrote:
[...]

 [3] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95661
     Bug 95661 - Code built with -m32 uses SSE2 instructions


 Reminds me of another GCC bug I encountered on Solaris/Pentium4 
 that appears to have been introduced around the 10.x 
 development as well.

 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103015


And this reminds me of

    https://issues.dlang.org/show_bug.cgi?id=12268
    Issue 12268 - full static linking does not work, unresolved 
__tls_get_addr
    (2014)

    
http://forum.dlang.org/thread/vewesvrimtnmcrtygjam forum.dlang.org
    dmd (v2.075.0): fully static linking: undefined reference to 
`__tls_get_addr'
    (2017)

I don't know if this is the right way to work around this issue:

    #define _GNU_SOURCE
    #include <dlfcn.h>

    __attribute__((force_align_arg_pointer)) void *__tls_get_addr 
(void *ti)
    {
       void *(*tga)(void*) = dlsym(RTLD_NEXT, "__tls_get_addr");
       if (! tga)
          return ti;
       return tga(ti);
    }
May 13 2022
prev sibling parent kdevel <kdevel vogtner.de> writes:
On Friday, 13 May 2022 at 05:56:23 UTC, kdevel wrote:

 [...]

 I am rebuilding GCC with --with-arch_32=pentium3 now [3].


The option is spelled

    --with-arch-32=pentium3

and the build compiler can be checked with

    $ gcc -m64 -Q --help=target |egrep -i 'math|arch'
      -march=                     		x86-64     <---
      -mfancy-math-387            		[enabled]
      -mfpmath=                   		sse
      -mno-fancy-math-387         		[disabled]
      Valid arguments to -mfpmath=:
      Known valid arguments for -march= option:

and

    $ gcc -m32 -Q --help=target |egrep -i 'math|arch'
      -march=                     		pentium3   <-----
      -mfancy-math-387            		[enabled]
      -mfpmath=                   		387
      -mno-fancy-math-387         		[disabled]
      Valid arguments to -mfpmath=:
      Known valid arguments for -march= option:
May 13 2022
prev sibling parent max haughton <maxhaton gmail.com> writes:
On Friday, 13 May 2022 at 03:33:24 UTC, kdevel wrote:

 After I encountered illegal instruction signals whith 
 dmd-generated code [1] I eventually bootstrapped GDC 11.3 and 
 12.1. Unfortunately the problem persists. A statically linked 
 program receives SIGILL, as gdb says this happens here:

 [...]


Based on 30 seconds on compiler explorer it looks like GCC 
started emitting movq around GCC 10.1-ish
May 12 2022