Re: [Gcl-devel] GCL on mingw

[Vadim V. Zhytnikov]

Camm Maguire ?????:
> Greetings!
>
> "Vadim V. Zhytnikov" <address@hidden> writes:
>
>
> > Camm Maguire ?????:
> >
> >
> > > Hi Vadim!  And thanks!
> > > OK, so now I believe this build uses the sbrk emulation routine found
> > > in unexnt.c.
> >
> > I don't think so. First of all there is no unexnt.o file in the
> > /o directory.  Second, I can't any line numbering information
>
>
> Actually, I think my original statement was correct.  Here is the line
> from mingw.h:
>
> /* use the slightly older unexec */
> #define UNIXSAVE "unexnt.c"
>
> You should have a unixsave.o, which should basically just be an
> include in this case of unexnt.c.

Yes. I overlooked this.
> > when stopped at sbrk after 'p sbrk(4096)'.  What I'm doing wrong?
> > Hrere is gdb session transcript:
> >
> >
> > $ gdb raw_gcl
> > GNU gdb 5.2.1
> > Copyright 2002 Free Software Foundation, Inc.
> > GDB is free software, covered by the GNU General Public License, and you are
> > welcome to change it and/or distribute copies of it under certain
> > conditions.
> > Type "show copying" to see the conditions.
> > There is absolutely no warranty for GDB.  Type "show warranty" for details.
> > This GDB was configured as "i686-pc-mingw32"...
> > (gdb) br initlisp
> > Breakpoint 1 at 0x402df5
> > (gdb) r ./ <foo
> > Starting program:
> > C:\msys\1.0\home\vadim\gcl-debug\unixport/raw_gcl.exe ./ <foo
> >
> > Breakpoint 1, 0x00402df5 in initlisp ()
> > (gdb) p /x sbrk(65080*4096)
> > $1 = 0x101c8000
> > (gdb) br sbrk
> > Breakpoint 2 at 0x478169
> > (gdb) p /x sbrk(4096)
> >
> > Breakpoint 2, 0x00478169 in sbrk ()
> > (gdb) The program being debugged stopped while in a function called
>
>
> How about try 'l' for list here, 'n' for next, or 's' for step? 

This was first thing I tried. But result was confusing.
And only after some head scratching I understood the reason of
all my troubles.  First, I have to instruct gdb about explicit
sources location at ../o and ../h and more serious second problem -
files in ../o were compiled without debug flag -g (it sees like
a configure/make bug at least on mingw).  After rebuilding with
-g option for all files I've got the following gdb session.
Notice that get_reserver_heap_size() is equal to reserved_heap_size.
In this session I first did sbrk for 65079 pages, then for 1 more
pages tracing sbrk (success) and one more page (failure).
The failure is not at VirtuallMalloc but at simple condition
1049          if ((data_region_end + size) >
1050              (data_region_base + get_reserved_heap_size ()))
==============================================================
$ gdb raw_gcl
GNU gdb 5.2.1
Copyright 2002 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain 
conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for details.
This GDB was configured as "i686-pc-mingw32"...
(gdb) dir ./ ../o ../h ../
Source directories searched: 
C:\msys\1.0\home\vadim\gcl-debug\unixport;C:\msys\1.0\home\vadim\gcl-debug\unixport/../o;C:\msys\1.0\home\vadim\gcl-debug\unixport/../h;C:\msys\1.0\home\vadim\gcl-debug\unixport/..;$cdir;$cwd
(gdb) br initlisp
Breakpoint 1 at 0x402df5: file main.c, line 403.
(gdb) r ./ <foo
Starting program: C:\msys\1.0\home\vadim\gcl-debug\unixport/raw_gcl.exe 
./ <foo

Breakpoint 1, initlisp () at main.c:403
403
(gdb) l
398
399     static void
400     initlisp(void) {
401
402             int j;
403
404             if (NULL_OR_ON_C_STACK(&j) == 0
405                 || NULL_OR_ON_C_STACK(Cnil) != 0
406                 || (((unsigned long )core_end) !=0
407                     && NULL_OR_ON_C_STACK(core_end) != 0))
(gdb) p /x &j
$1 = 0x22ff64
(gdb) p /x &Cnil_body
$2 = 0x54d1a0
(gdb) p /x core_end
$3 = 0x101c8000
(gdb) info dll
DLL Name                          Load Address
ntdll.dll                         77f51000
C:\WINDOWS\system32\kernel32.dll  77e61000
C:\WINDOWS\system32\msvcrt.dll    77c01000
C:\WINDOWS\system32\user32.dll    77d31000
C:\WINDOWS\system32\gdi32.dll     77c61000
C:\WINDOWS\system32\advapi32.dll  77dc1000
C:\WINDOWS\system32\rpcrt4.dll    77cb1000
C:\WINDOWS\System32\wsock32.dll   71ab1000
C:\WINDOWS\System32\ws2_32.dll    71a91000
C:\WINDOWS\System32\ws2help.dll   71a81000
(gdb) p /x sbrk(65079*4096)
$4 = 0x101c8000
(gdb) br sbrk
Breakpoint 2 at 0x478169: file unexnt.c, line 993.
(gdb) p /x sbrk(4096)

Breakpoint 2, sbrk (increment=4096) at unexnt.c:993
993       long size = (long) increment;
(gdb) The program being debugged stopped while in a function called from 
GDB.
When the function (sbrk) is done executing, GDB will silently
stop (instead of continuing to evaluate the expression containing
the function call).
l
988     /* Emulate Unix sbrk.  */
989     void *
990     sbrk (unsigned long increment)
991     {
992       void *result;
993       long size = (long) increment;
994
995       /* Allocate our heap if we haven't done so already.  */
996       if (data_region_base == UNINIT_PTR)
997         {
(gdb) s
996       if (data_region_base == UNINIT_PTR)
(gdb) s
1015      result = data_region_end;
(gdb) s
1018      if (size < 0)
(gdb) p data_region_base
$5 = (unsigned char *) 0x10100000 "\r"
(gdb) p data_region_end
$6 = (unsigned char *) 0x1ffff000 <Address 0x1ffff000 out of bounds>
(gdb) p data_region_size
$7 = 267386880
(gdb) p reserved_heap_size
$8 = 267386880
(gdb) s
1046      else if (size > 0)
(gdb) s
1049          if ((data_region_end + size) >
(gdb) l
1044        }
1045      /* If size is positive, grow the heap by committing reserved 
pages.  */
1046      else if (size > 0)
1047        {
1048          /* Sanity checks.  */
1049          if ((data_region_end + size) >
1050              (data_region_base + get_reserved_heap_size ()))
1051            return NULL;
1052
1053          /* Commit more of our heap. */
(gdb) s
1054          if (VirtualAlloc (data_region_end, size, MEM_COMMIT,
(gdb) s
1057          data_region_end += size;
(gdb) s
1061          real_data_region_end = (unsigned char *)
(gdb) s
1065      return result;
(gdb) s
1066    }
(gdb) l
1061          real_data_region_end = (unsigned char *)
1062              ((long) (data_region_end + syspage_mask) & ~syspage_mask);
1063        }
1064
1065      return result;
1066    }
1067
1068    /* Recreate the heap from the data that was dumped to the 
executable.
1069       EXECUTABLE_PATH tells us where to find the executable.  */
1070    void
(gdb) finish
Run till exit from #0  sbrk (increment=4096) at unexnt.c:1066
Value returned is $9 = (void *) 0x1ffff000
(gdb) p /x sbrk(4096)

Breakpoint 2, sbrk (increment=4096) at unexnt.c:993
993       long size = (long) increment;
(gdb) The program being debugged stopped while in a function called from 
GDB.
When the function (sbrk) is done executing, GDB will silently
stop (instead of continuing to evaluate the expression containing
the function call).
s
996       if (data_region_base == UNINIT_PTR)
(gdb) s
1015      result = data_region_end;
(gdb) s
1018      if (size < 0)
(gdb) s
1046      else if (size > 0)
(gdb) p data_region_base
$10 = (unsigned char *) 0x10100000 "\r"
(gdb) p data_region_end
$11 = (unsigned char *) 0x20000000 <Address 0x20000000 out of bounds>
(gdb) p data_region_size
$12 = 267386880
(gdb) p reserved_heap_size
$13 = 267386880
(gdb) s
1049          if ((data_region_end + size) >
(gdb) l
1044        }
1045      /* If size is positive, grow the heap by committing reserved 
pages.  */
1046      else if (size > 0)
1047        {
1048          /* Sanity checks.  */
1049          if ((data_region_end + size) >
1050              (data_region_base + get_reserved_heap_size ()))
1051            return NULL;
1052
1053          /* Commit more of our heap. */
(gdb) s
1051            return NULL;
(gdb) s
1066    }
(gdb) finish
Run till exit from #0  sbrk (increment=4096) at unexnt.c:1066
Value returned is $14 = (void *) 0x0
(gdb)
=======================================================================



--
     Vadim V. Zhytnikov

      <address@hidden>
     <address@hidden>