Request to commit - ARM + Shark - OSR support

[Andrew Haley]

Edward Nevill wrote:

> The following patch adds OSR support to ARM + Shark.
> 
> It also fixes a number of bugs. The most important of these is a
> change to src/share/vm/interpreter/bytecodeInterpreter.cpp.
> 
> This change is necessary because the C bytecode interpreter does not
> support rewritten bytecodes. Instead it just throws a fatal error.
> Now the Asm Interpreter does in fact rewrite some of the bytecodes.
> 
> Now with Shark support, the Shark JIT may in fact call the C
> interpreter with a method which has bytecodes which have been rewritten
> by the Asm interpreter. In fact, this was a bug all along as the
> Asm interpreter can back out to the C interpreter in a number of
> cases, most notably if JVMTI is enabled.
> 
> What the change does is, in the default case, it looks up the original
> bytecode. If the current bytecode != the original it uses the original
> as the opcode instead and tries the bytecode again.
> 
> Here is the actual diff for bytecodeInterpreter.cpp extracted from the
> bigger diff below.

It's great to see this working.  A couple of things:

Please don't add "ECN" to the comments.

Is this C++ interp change something that should go upstream?

Andrew.