[kaffe] mipsel JIT3

[Casey Marshall]

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Hi,

I've started hacking around the JIT3 sources, and have found at least
the first point of failure: spill() in jit3/register.c is being called
in such a way that reginfo[s->regno].ctype is 0, i.e. it's type field
is unset. This causes an immediate ABORT because there is (obviously)
no way to spill an untyped register. s->regno has always been 12 when
this happens, and this is the first time this register is ever
spilled.

Along the culprit's trail is a call to slotAlias (jit3/machine.c),
which increments the reference count of reginfo[12], but leaves the
ctype field untouched, so when that register is requested (push_float
does this) it will be incorrectly spilled. So far I can't tell whether
or not this is the fault of the mips-specific code, since I can't
really get a stack trace far back enough.

My suspicion is that the mips code doesn't properly free a register or
slot, but I wanted to ask if anyone here has any idea why this
situation might come up.

Secondly: if I hack slotRegister() to fill in ctype if it is blank, I
get further, but then Float.isNaN returns false when given NaN,
causing toCharArrayWithPrecision to barf. This has got to be a
mips-specific bug.

Cheers,

- -- 
Casey Marshall || rsdio at metastatic.org
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