Safe points are exported in a per-module list via the crate map. A C
runtime call walks the crate map at startup and aggregates the list of
safe points for the program.
Currently the GC doesn't actually deallocate memory on malloc and
free. Adding the GC at this stage is primarily of testing value.
The GC does attempt to clean up exchange heap and stack-allocated
resource on failure.
A result of this patch is that the user now needs to be careful about
what code they write in destructors, because the GC and/or failure
cleanup may need to call destructors. Specifically, calls to malloc
are considered unsafe and may result in infinite loops or segfaults.
Make all glue functions take values by alias to remove the need for
bitcasts at the top of every glue function. Use static type
information to produce the correct type for glue functions so that
LLVM can enforce the type system at call sites.
API is (for now) mostly by value, there are options to use it by
reference if you like. Hash and equality functions must be pure
and by reference (forward looking to the day when something
like send_map becomes the standard map).
Updating types std::sha1::sha1 -> hash::streaming was a relatively
small change. Renaming the variables to reflect that things aren't
sha1s any more touched far more lines.
We can't throw an exception from inside a landing pad without
corrupting the exception handler, so we have no hope of dealing with
these exceptions anyway. See:
http://llvm.org/docs/ExceptionHandling.html#cleanups
Part of #2861.
This comes with a terminology change. All linkage-symbols are 'extern'
now, including rust syms in other crates. Some extern ABIs are
merely "foreign". The term "native" is retired, not clear/useful.
What was "crust" is now "extern" applied to a _definition_. This
is a bit of an overloading, but should be unambiguous: it means
that the definition should be made available to some non-rust ABI.
And replace trans::common::block_parent with option<block>. To handle
the recursive self-reference in the block_ class, I had to add a
newtype-like enum "block" which is equivalent to @block_ -- which due
to an interaction with borrowck, resulted in having to change a few
functions in trans::base to take their block argument in ++ mode,
irritatingly enough (but not that irritatingly, since we're supposed to
get rid of modes).
