This is the culmination and attempted resolution of #8215. The commits have many more details about implementation details and the consequences of this refinement.
I'll point out specific locations which may be possible causes for alarm. In general, I have been very happy with how things have turned out. I'm a little sad that I couldn't remove privacy from resolve as much as I did, but I blame glob imports (although in theory even some of this can be mitigated as well).
This removes the warning "Note" about visibility not being fully defined, as it
should now be considered fully defined with further bugs being considered just
bugs in the implementation.
This commit fixes all of the fallout of the previous commit which is an attempt
to refine privacy. There were a few unfortunate leaks which now must be plugged,
and the most horrible one is the current `shouldnt_be_public` module now inside
`std::rt`. I think that this either needs a slight reorganization of the
runtime, or otherwise it needs to just wait for the external users of these
modules to get replaced with their `rt` implementations.
Other fixes involve making things pub which should be pub, and otherwise
updating error messages that now reference privacy instead of referencing an
"unresolved name" (yay!).
This commit is the culmination of my recent effort to refine Rust's notion of
privacy and visibility among crates. The major goals of this commit were to
remove privacy checking from resolve for the sake of sane error messages, and to
attempt a much more rigid and well-tested implementation of visibility
throughout rust. The implemented rules for name visibility are:
1. Everything pub from the root namespace is visible to anyone
2. You may access any private item of your ancestors.
"Accessing a private item" depends on what the item is, so for a function this
means that you can call it, but for a module it means that you can look inside
of it. Once you look inside a private module, any accessed item must be "pub
from the root" where the new root is the private module that you looked into.
These rules required some more analysis results to get propagated from trans to
privacy in the form of a few hash tables.
I added a new test in which my goal was to showcase all of the privacy nuances
of the language, and I hope to place any new bugs into this file to prevent
regressions.
Overall, I was unable to completely remove the notion of privacy from resolve.
One use of privacy is for dealing with glob imports. Essentially a glob import
can only import *public* items from the destination, and because this must be
done at namespace resolution time, resolve must maintain the notion of "what
items are public in a module". There are some sad approximations of privacy, but
I unfortunately can't see clear methods to extract them outside.
The other use case of privacy in resolve now is one that must stick around
regardless of glob imports. When dealing with privacy, checking a private path
needs to know "what the last private thing was" when looking at a path. Resolve
is the only compiler pass which knows the answer to this question, so it
maintains the answer on a per-path resolution basis (works similarly to the
def_map generated).
Closes#8215
This implements the necessary logic for gating particular features off by default in the compiler. There are a number of issues which have been wanting this form of mechanism, and this initially gates features which we have open issues for.
Additionally, this should unblock #9255
This pull request changes to memory layout of the `CrateMap` struct to use static slices instead of raw pointers. Most of the discussion took place [here](63b5975efa (L1R92)) .
The memory layout of CrateMap changed, without bumping the version number in the struct. Another, more backward compatible, solution would be to keep the old code and increase the version number in the new struct. On the other hand, the `annihilate_fn` pointer was removed without bumping the version number recently.
At the moment, the stage0 compiler does not use the new memory layout, which would lead the segfaults during stage0 compilation, so I've added a dummy `iter_crate_map` function for stage0, which does nothing. Again, this could be avoided if we'd bump the version number in the struct and keep the old code.
I'd like to use a normal `for` loop [here](https://github.com/fhahn/rust/compare/logging-unsafe-removal?expand=1#L1R109),
for child in children.iter() {
do_iter_crate_map(child, |x| f(x), visited);
}
but for some reason this only yields `error: unresolved enum variant, struct or const 'Some'` and I have no idea why.
A few features are now hidden behind various #[feature(...)] directives. These
include struct-like enum variants, glob imports, and macro_rules! invocations.
Closes#9304Closes#9305Closes#9306Closes#9331
The root issue is that dlerror isn't reentrant or even thread safe.
The solution implemented here is to make a yielding spin lock over an
AtomicFlag. This is pretty hacky, but the best we can do at this point.
As far as I can tell, it isn't possible to create a global mutex without
having to initialize it in a single threaded context.
The Windows code isn't affected since errno is thread-local on Windows
and it's running in an atomically block to ensure there isn't a green
thread context switch.
Closes#8156
This PR solves one of the pain points with c-style enums. Simplifies writing a fn to convert from an int/uint to an enum. It does this through a `#[deriving(FromPrimitive)]` syntax extension.
Before this is committed though, we need to discuss if `ToPrimitive`/`FromPrimitive` has the right design (cc #4819). I've changed all the `.to_int()` and `from_int()` style functions to return `Option<int>` so we can handle partial functions. For this PR though only enums and `extra::num::bigint::*` take advantage of returning None for unrepresentable values. In the long run it'd be better if `i64.to_i8()` returned `None` if the value was too large, but I'll save this for a future PR.
Closes#3868.
The root issue is that dlerror isn't reentrant or even thread safe.
The Windows code isn't affected since errno is thread-local on Windows
and it's running in an atomically block to ensure there isn't a green
thread context switch.
Closes#8156
