Re: DImode operations

[Dave Korn <dave.korn.cygwin@googlemail.com>]

daniel tian wrote:
> Thanks. I am working for it now.
> But I have a question about how to debug the cc1 with libgcc1.c.
> because if I run the cc1 to build the libgcc2.c, lots of errors
> occurred.
> 
> Run the cc1 with the command:
> ./cc1 -g -I../../rice-gcc-4.3.0/gcc
> -I../../rice-gcc-4.3.0/gcc/../include
> ../../rice-gcc-4.3.0/gcc/libgcc2.c
> 
> here is the error message:

> Did I do something wrong?

  Yes, it can't work that simply; the code in libgcc2.c needs a bunch of
macros defined and some other -I paths as well before it will work.  One way
is to

- in the gcc/ subdir of your build directory, delete one of the libgcc .o
files that you want to test your new compiler against
- run "make 2>&1 | tee build.log" to capture the xgcc command that the
makefile generates to rebuild that .o file.
- copy and paste the commandline from the build log and add "-v 2>&1 | tee
rebuild.log" at the end to capture the way the xgcc driver invokes cc1
- copy and paste /that/ commandline, and put "gdb --args" at the front of it
to debug your compiler.

  See also http://gcc.gnu.org/wiki/DebuggingGCC

    cheers,
      DaveK