Looks good so far reading the ast --ir output. A few things on which I
could use clarification:
* Binding variable load/stores are unconditionally done before/after
block calls, yes? Opportunity to optimize or failover to all binding
variables if we see there's a lot of churn?
* Are all variables bound regardless of usage in the block?
(proc-as-binding, grrr)
* I have not yet looked at the linearized code to see how the ensure
logic fires. Judging by the output, the normal and exceptional paths
are already encoded separately, which is how I'd hope to see it.
* Depending on how we encode $~ and $_, they could be treated as
binding locals too.
At the moment I'm going to implement this with the method body
allocating the DynamicScope *and* doing the push/pop. If we can
eliminate the need for pushing the scopes onto an external
thread-local structure (i.e. pass it along call stack, which indy will
help with) the pushing, popping, and finally/ensure logic can
disappear and we'll *just* have the scope allocation (i.e. pop will be
a no-op). That would definitely be the ideal, since it would allow for
bindings to eventually escape-analyze away (once we get the JVM to
inline through to closures).
- Charlie
On Tue, May 8, 2012 at 2:14 AM, Charles Oliver Nutter
<head...@headius.com> wrote:
> I will look into this a bit tonight and see if I can get basic binding
> logic implemented in IR2JVM. Thanks, Subbu!
>
> On Mon, May 7, 2012 at 8:48 PM, Subramanya Sastry <sss.li...@gmail.com> wrote:
>> I started working on implementing an explicit call protocol last week.
>> It required me to clean up a few other bits which I did over several commits
>> since y'day.
>>
>> I now committed a first cut at AddExplicitCallProtocolInstructions compiler
>> pass.
>>
>> I tested this with the interpreter and it seeks to run fine. There may be
>> bugs in corner cases ... but I haven't run into it running rubyspecs, gem
>> list, and irb.
>>
>> To take full advantage of this, you need to run the following 2 passes:
>> AddLocalVarLoadStoreInstructions, AddExplicitCallProtocolInstructions, and
>> implement compiler code for PushBinding, PopBinding, LoadLocalVar and
>> StoreLocalVar instructions.
>>
>> Ex: jruby -X-CIR
>> -Xir.passes=OptimizeTempVarsPass,LocalOptimizationPass,DeadCodeElimination,AddLocalVarLoadStoreInstructions,AddCallProtocolInstructions,LinearizeCFG
>> bench/bench_fib_recursive.rb
>>
>> Subbu.
>>
>> PS: There is one private patch for operands/TemporaryVariable that I have
>> not yet committed -- this has got to do with handling use-before-defs in
>> Ruby. This is normally not required for tmps but with explicit load/store
>> of local-vars, this becomes necessary since all local vars are now pushed
>> into temp vars (and java local vars in the compiler). This patch is
>> required for gem list and for getting "green" on rubyspecs, for ex. This
>> only affects the interpreter, not the compiler since I presume you have this
>> logic there anyway. The patch is trivial (enclosed below)
>>
>> @Override
>> public Object retrieve(ThreadContext context, IRubyObject self,
>> DynamicScope currDynScope, Object[] temp) {
>> - return temp[offset];
>> + Object o = temp[offset];
>> + return o == null ? context.nil : o;
>> }
>>
>> I have not committed this because I was hoping that we could find a way to
>> eliminate this (both here and in DynamicScope.java:getValueOrNil ) by
>> canonicalizing the instr stream to eliminate use-before-defs in ruby code --
>> I dont yet have a cheap fix for it, so haven't implemented yet, but maybe I
>> should just commit this patch and forget about it for now.
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