Re: building gcc against eclipse?

[Andrew Haley <aph at redhat dot com>]

Jack Howarth wrote:
> 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.

>    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. 

You mean the class org.eclipse.jdt.internal.compiler.batch.GCCMain is missing, I guess?

>   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?

Sure.  Just put the file GCCMain.class in someDirectory, and run ecj1 as

#!/bin/sh
exec gij -cp someDirectory:/usr/share/java/eclipse-ecj.jar org.eclipse.jdt.internal.compiler.batch.GCCMain "\$@"

Andrew.