It turned out that function preconditions weren't getting checked
at all, so you could write a constraint on a fn decl that was total
nonsense. Fixed now.
It assumed node_ids increased monotonically for locals, but macros
make this no longer the case, and it was a dubious assumption anyway.
It now numbers locals itself and uses that to determine which precede
which.
The uniformity doesn't seem to be worth the extra noise and pointless
code being generated. If something doesn't produce a value, don't make
it return one. (For now, trans_[exprtype] things are left in the result-
returning form, even when they never return anything useful, since in
that case uniformity is arguably helpful.)
Vectors are now similar to our old, pre-internal vectors, except that
they are uniquely owned, not refcounted.
Their name should probably change too, then. I've renamed them to vec
in the runtime, will do so throughout the compiler later.
We continue to leak string buffers in trans so this creates a way to get c
string buffers from strings while guaranteeing that they are not freed before
use.
Hopefully this can be made efficient in the istr regime.
The glue-calling will spill the values again anyway. This should
prevent a lot of load/spill junk in the output. It is also necessary
to be able to have unique vecs be immediate values (take must know the
actual address to be able to duplicate).
trans_be now has a precondition that its expression argument
is a call expr. Obviously this code may be going away soon, but
I wanted to exercise typestate somehow and this was an easy one :-)
This patch supports the syntax
unchecked {
...
}
to disable purity checking within a block. Presumably it will only be
used within a declared "pure fn". However, there is no checking that it
doesn't occur elsewhere, and it would be harmless for it to do so.
I went with Lindsey's suggestion for the syntax, but it's subject to
change.
This allows you to write code that uses predicates that call arbitrary
Rust functions, but you must declare your intentions by wrapping it in
an unchecked { ... } block. The test case run-pass/unchecked-predicates.rs
demonstrates how to do that.
