Java GC descriptor vs. tree_int_cst on 64-bit platforms

Tue Mar 27 17:57:00 GMT 2001

> -----Original Message-----
> From: Richard Henderson [ mailto:rth@redhat.com ]
> On Tue, Mar 27, 2001 at 03:05:03PM -0800, Boehm, Hans wrote:
> > 1) The low and high field are 32 bits each. (The comment 
> in tree.def seems
> > to imply this.)
> [...]
> > - Is there agreement that view (1) should be correct?
>> No.

Meaning there is agreement that low contains all 64 bits in this case, and
the comment around line 262 of tree.def is wrong?
On closer inspection, that seems to be what the constant folding code, for
example, is assuming.
In light of that, here's my revised theory as to what's going on:
(Corrections appreciated.)
Get_boehm_type_descriptor should be returning a one word long constant. It
currently returns a constant generated with build_int_2, which is always a
32 bit constant, even on a 64 bit platform. The function should be setting
TREE_TYPE(value) to be a pointer length integer at the end. There seems to
be no way to do this in the Java front end without an explicit test on the
size of a pointer?
I'll try building a suitably hacked compiler an see if it helps.

Hans