gen_i2c_adapter problem on x86_64

[John Rose]

On Sep 8, 2009, at 1:36 AM, Christian Thalinger wrote:

> At least when we have a C2I-I2C call path.

OK, that's the new part.  In order to do some of the argument  
shuffling, adapter method handles can go through a C2I-I2C transition  
pair.

This is why we need the extra support for preserving SP in compiled  
calls to method handles, and why MH.invoke calls must (on x86/32)  
stash the outgoing SP in BP.  We need a similar convention on x86/64.

-- John