gcj: disabling synchronization

[Jeff Sturm]

I'm thinking about adding a flag to gcj to disable synchronization for
single-threaded programs (i.e. when libgcj is built without
--enable-threads), something like -fno-synchronized perhaps.

I've found that synchronized blocks incur significant overhead in
single-threaded code, particularly when configured with SJLJ_EXCEPTIONS.

It's easy to defeat synchronized methods in decl.c.  Synchronized
blocks are a little harder... I didn't completely understand the tree
structure created by patch_synchronized_statement.  It may be obvious to
anyone who understands the compiler internals (which I certainly don't).

Does anyone think this would be worthwhile for gcj?

--
Jeff Sturm
jsturm@sigma6.com