Re: building gcc against eclipse?

[Jack Howarth <howarth at bromo dot med dot uc dot edu>]

On Tue, Nov 10, 2009 at 10:00:29AM +0000, Andrew Haley wrote:
> Jack Howarth wrote:
>>    In fink, we have been building the gcj ecj1 support by
>> copying the ecj-latest.jar file from ftp://sourceware.org/pub/java
>> into the top level of the gcc source directory. I would like to try
>> building gcc on darwin with the eclipse compiler instead. We have
>> a fink ecj package which provides...
>>
>> /.
>> /sw
>> /sw/bin
>> /sw/bin/ecj
>> /sw/share
>> /sw/share/doc
>> /sw/share/doc/ecj
>> /sw/share/doc/ecj/about.html
>> /sw/share/java
>> /sw/share/java/ecj
>> /sw/share/java/ecj/ecj.jar
>>
>> How exactly does one build the gcj against this ecj compiler? Would 
>> creating a symlink in the toplevel gcc directory to
>> /sw/share/java/ecj/ecj.jar be sufficient to cause the installed
>> eclipse compiler to be used for ecj1?
>
> We configure for Fedora with --with-ecj-jar=/usr/share/java/eclipse-ecj.jar
> You don't have to copy that jar into the toplev of srcdir.
>
> Andrew.

Andrew,
   Would there be any possible differences in the code execution of gcj when built
with the stock ftp://sourceware.org/pub/java/ecj-latest.jar compared to the ecj.jar
from eclipse? My initial attempts at building a usable gcj with eclipse's ecj.jar
failed due to undefined symbols for org.eclipse.jdt.internal.compiler.batch.GCCMain
at runtime for ecj1. 
  I noticed that the fedora 12 gcc specfile at...

http://cvs.fedoraproject.org/viewvc/rpms/gcc/F-12/gcc.spec?revision=1.90&view=markup

has a section...

        %if %{build_java}
        %if !%{bootstrap_java}
        # If we don't have gjavah in $PATH, try to build it with the old gij
        mkdir java_hacks
        cd java_hacks
        cp -a ../../libjava/classpath/tools/external external
        mkdir -p gnu/classpath/tools
        cp -a ../../libjava/classpath/tools/gnu/classpath/tools/{common,javah,getopt} gnu/classpath/tools/
        cp -a ../../libjava/classpath/tools/resource/gnu/classpath/tools/common/Messages.properties gnu/classpath/tools/common
        cp -a ../../libjava/classpath/tools/resource/gnu/classpath/tools/getopt/Messages.properties gnu/classpath/tools/getopt
        cd external/asm; for i in `find . -name \*.java`; do gcj --encoding ISO-8859-1 -C $i -I.; done; cd ../..
        for i in `find gnu -name \*.java`; do gcj -C $i -I. -Iexternal/asm/; done
        gcj -findirect-dispatch -O2 -fmain=gnu.classpath.tools.javah.Main -I. -Iexternal/asm/ `find . -name \*.class` -o gjavah.r
eal
        cat > gjavah <<EOF
        #!/bin/sh
        export CLASSPATH=`pwd`${CLASSPATH:+:$CLASSPATH}
        exec `pwd`/gjavah.real "\$@"
        EOF
        chmod +x `pwd`/gjavah
        cat > ecj1 <<EOF
        #!/bin/sh
        exec gij -cp /usr/share/java/eclipse-ecj.jar org.eclipse.jdt.internal.compiler.batch.GCCMain "\$@"
        EOF
        chmod +x `pwd`/ecj1
        export PATH=`pwd`${PATH:+:$PATH}
        cd ..
        %endif
        %endif

This would be difficult to implement in fink for darwin since we don't have legacy gij/gcj compiler to
leverage from the system compilers. Is there another way to get around the issue of the undefined
org.eclipse.jdt.internal.compiler.batch.GCCMain symbol in ejc1 when using the ecj.jar from eclipse?
             Jack