It's unclear to me why these currently aren't allowed, and my best guess is that
a long time ago we didn't strip the ast of cfg nodes before syntax expansion.
Now that this is done, I'm not certain that we should continue to prohibit this
functionality.
This is a step in the right direction towards #5605, because now we can add an
empty `std::macros` module to the documentation with a bunch of empty macros
explaining how they're supposed to be used.
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
According to http://huonw.github.io/isrustfastyet/mem/#012f909, the "const
marking" pass generates about 400MB of extra memory during compilation. It
appears that this is due to two different factors:
1. There is a `ccache` map in the ty::ctxt which is only ever used in this
pass, so this commit moves the map out of the ty::ctxt struct and into
just this pass's visitor. This turned out to not benefit that much in
memory (as indicated by http://i.imgur.com/Eo4iOzK.png), but it's helpful
to do nonetheless.
2. During const_eval, there are a lot of lookups into decoding inlined items
from external crates. There is no caching involved here, so the same
static or variant could be re-translated many times. After adding
separate caches for variants and statics, the memory peak of compiling
rustc decreased by 200MB (as evident by http://i.imgur.com/ULAUMtq.png)
The culmination of this is basically a slight reorganization of a caching map
for the const_eval pass along with a 200MB decrease in peak memory usage when
compiling librustc.
According to http://huonw.github.io/isrustfastyet/mem/#012f909, the "const
marking" pass generates about 400MB of extra memory during compilation. It
appears that this is due to two different factors:
1. There is a `ccache` map in the ty::ctxt which is only ever used in this
pass, so this commit moves the map out of the ty::ctxt struct and into
just this pass's visitor. This turned out to not benefit that much in
memory (as indicated by http://i.imgur.com/Eo4iOzK.png), but it's helpful
to do nonetheless.
2. During const_eval, there are a lot of lookups into decoding inlined items
from external crates. There is no caching involved here, so the same
static or variant could be re-translated many times. After adding
separate caches for variants and statics, the memory peak of compiling
rustc decreased by 200MB (as evident by http://i.imgur.com/ULAUMtq.png)
The culmination of this is basically a slight reorganization of a caching map
for the const_eval pass along with a 200MB decrease in peak memory usage when
compiling librustc.
Avoid cloning the stack on every `push_ctxt` call in trans
Rewrite the use of TLS variable for `push_ctxt` so that it uses a ~[]
instead of a @~[]. Before it cloned the whole vector on each push and
pop, which is unnecessary.
Rewrite the use of TLS variable for `push_ctxt` so that it uses a ~[]
instead of a @~[]. Before it cloned the whole vector on each push and
pop, which is unnecessary.
rustc: Use static strings in a few literals
Avoid allocating extra copies of strings by using "" instead of ~"" for
the debug options list and for the `time` function. This is a small
change, but it is in a path that's always executed.
Avoid allocating extra copies of strings by using "" instead of ~"" for
the debug options list and for the `time` function. This is a small
change, but it is in a path that's always executed.
