Re: [Cp-tools-discuss] gnu.bytecode

[Per Bothner]

Elliott Hughes wrote:

> On Dec 29, 2004, at 22:36, C. Brian Jones wrote:
>
> > On Wed, 2004-12-29 at 22:57, Elliott Hughes wrote:
> >
> > > is this the right/a sensible place to talk about gnu.bytecode?

I'm not on the cp-tools-discuss list, so I'm afraid I don't know the
context.

> there are two problems. one is that nothing writes to the start_pc and 
> end_pc fields in Variable,

These fields are now gone.

I suggest trying the latest version of gnu.bytecode from the Kawa
cvs repository.  Note this is on sources.redhat.com, for historial
reasons  See http://www.gnu.org/software/kawa/Getting-Kawa.html

> i think the intent was probably that the start_pc and end_pc fields 
> would be removed from Variable, and the Variable's Scope's start and end 
> Label instances' position fields would be used for that information.

Yep.

> i'm not convinced that works in general. nothing i've seen says that the 
> range of bytecode indexes for which a slot contains a given variable has 
> to correspond to a scope in the usual sense.

Think of a scope as a range of bytecode, in that case.

> my fix doesn't create any new Scope instances, 

I'm not sure what the context is.
However, the ClassFileInput parses a .class files, and creates the
needed LocalVarsAttr.  It is rather simpleminded: it creates a
new Scope and a new pair of Labels each time the start_pc or end_pc
is diferent from the previous variable.

> try gnu.classpath.tools.JavapMain or gnu.bytecode.dump on a class
> compiled with "javac -g" to see

Hm.  Something does seem to be broken.  I'll look into it quickly.

> at the same time, a more direct mapping to/from the class file format 
> would be handy for my purposes. and something that's a complete and 
> direct implementation of chapter 4, and which makes reference to it, 
> would be nice.

gnu.bytecode strives to be a very direct (and low-overhead) mapping from
the classfile  format.
--
        --Per Bothner
address@hidden   http://per.bothner.com/