Mail Archives: djgpp/2014/08/24/14:39:47
Am 24.08.2014 17:06, schrieb Eli Zaretskii:
[snip]
> - If the sources are configured without --no-debug and -O2 flag then the
> build fails with the following error message:
> [snip]
> ./temacs -batch -l loadup dump
> Cannot open load file: Value too large (EOVERFLOW), loadup.el
> openp: (fstat call) fn = d:/emacs-24.3.93-debug-O2-490/lisp/loadup.el fd = 7 err = 40 <-- I have added this printf() line in openp.
> Makefile:192: recipe for target '../lisp/leim/leim-list.el' failed
> make.exe[1]: *** [../lisp/leim/leim-list.el] Error -1
> make.exe[1]: Leaving directory 'd:/emacs-24.3.93-debug-O2-490/src'
> Makefile:105: recipe for target 'src' failed
> make.exe: *** [src] Error 2
>
> As can be seen, this time temacs.exe is successfully build but it did
> not work. The reason for the failure is that fstat sets errno = EOVERFLOW.
> fstat is called in openp() of lread.c at line 1621.
> Tomorrow I will compile a debug version of libc.a and check why fstat
> behavior is different on WinXP/Win98SE and on MSDOS.
> Yes, it is IMO very important to understand why.
The bug is related to the checking of the availability of 0x71NN functions.
fstat calls fstat_assist and this function calls __filelength. This function
together with a lot of other LFN functions have been known to be broken in the
sense that they did either not set the carry flag before calling the function
or they did not check that the content of the AX register is different from
0x7100 after calling the 0x71NN function to verify that the LFN driver does
really support the called 0x71NN function.
The issue has already been fixed in repository and if I use a libc.a version
compiled from repository sources then this bug does not appear at all. This
issue has already been reported some years ago but unfortunately I had forgotten
about it. See:
http://www.delorie.com/archives/browse.cgi?p=djgpp/2011/08/30/18:59:04
The bottom line of this is that djdev204 cannot be used to compile software
that shall be used on plain DOS together with DOSLFN. Although the latest
DOSLFN version sets the carry flag to solve this well known DJGPP specific
bug it cannot solve for the missing check of AX != 0x7100 to determinate if
the required function is really supported by the driver. Because WinXP and
Win98SE (DOS box in the GUI) support all functions the bug never appears.
As soon as I use plain DOS either as MSDOS 6.22 or as DOS 7.1 from Win98SE
and I load the LFN driver all programs that call LFN functions not supported
by the driver make the program file. Usually with: Value too large (EOVERFLOW).
>> 3) On MSDOS 6.22 with DOSLFN 0.41c using gcc334, bnu224br2 and djdev204.
>> It is not possible to compile the sources at all. Compiling without
>> --no-debug and with -O0 or -O2 flag aborts the compilation with the
>> following error message:
>> [snip]
>> C:/DJGPP-2.04/BIN/make.exe all-am
>> make.exe[2]: Entering directory 'd:/emacs-24.3.93-debug-O2-344/lib'
>> gcc -I. -Id:/emacs-24.3.93-debug-O2-344/lib -I../src -Id:/emacs-24.3.93-debug-O2-344/src -g -O2 -MT c-ctype.o -MD -MP -MF deps/c-ctype.Tpo -c -o c-ctype.o c-ctype.c
>> cc1.exe: c-ctype.c: Value too large (EOVERFLOW)
>> Makefile:1562: recipe for target 'c-ctype.o' failed
>> make.exe[2]: *** [c-ctype.o] Error 1
>> make.exe[2]: Leaving directory 'd:/emacs-24.3.93-debug-O2-344/lib'
>> Makefile:1463: recipe for target 'all' failed
>> make.exe[1]: *** [all] Error 2
>> make.exe[1]: Leaving directory 'd:/emacs-24.3.93-debug-O2-344/lib'
>> Makefile:86: recipe for target 'lib' failed
>> make.exe: *** [lib] Error 2
> FWIW, I use GCC is 3.4.4 and Binutils 2.19.
>
>> The bottom line is that debugging emacs becomes really difficult due to the COFF
>> debug format issues.
> The problem with going to DWARF-2 debug info is that last time I tried
> the dumped Emacs crashed at startup. If you try it now and it works
> for you, or of you (or someone else) finds and fixes the problem that
> causes the crash, I have no problems supporting the DWARF-2 build.
> Otherwise, we are stuck with COFF.
No, it does not work with DWARF-2 so we have to keep with COFF debug support.
Regards,
Juan M. Guerrero
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