These variants occur rarely but inflate the whole enum for the other variants, leaving a lot of wasted space. In total this reduces `ty::sty` from 160 bytes to 96 (on a 64-bit platform).
After this, `ty_struct` and `ty_enum` are the largest variants, with the 80-byte `substs` being the major contributor.
This fixes struct passing abi on x86 ffi: Structs are now passed
indirectly with byval attribute (as clang does).
Empty structs are also explicitly ignored rather than directly passed.
Fixes#5744Fixes#11198Fixes#11343
This reduces the size of sty from 112 to 96; like with the ty_trait
variant, this variant of sty occurs rarely (~1%) so the benefits are
large and the costs small.
This reduces ty::sty from 160 bytes to just 112, and some measurements
eddyb made suggest that the ty_trait variant occurs very
rarely (e.g. ~1% of all sty instances) hence this will result in a large
memory saving, and the cost of the indirection is unlikely to be an
issue.
Remove the linker_private and linker_private_weak linkage attributes,
they have been superseded by private and private_weak and have been
removed in upstream LLVM in commit r203866.
The pretty printer constitues an enormous amount of code, there's no reason for
it to be generic. This just least to a huge amount of metadata which isn't
necessary. Instead, this change migrates the pretty printer to using a trait
object instead.
Closes#12985
This takes the time for `rustc libstd/lib.rs -Z ast-json-noexpand >
file.json` from 9.0s to 3.5s (~0.5s spent parsing etc.) and `-Z
ast-json` from 11s to 5s (~1.5s spent parsing and expanding).
This is adequate because when a function has a type that isn't caught here,
that is, it has a single argument, but it *isn't* `&mut BenchHarness`, it
errors later on with:
error: mismatched types: expected `fn(&mut test::BenchHarness)` but found
`fn(int)` (expected &-ptr but found int)
which I consider acceptable.
Closes#12997
This PR enables the use of mutable slices in *mutable* static items. The work was started by @xales and I added a follow-up commit that moves the *immutable* restriction to the recently added `check_static`
Closes#11411
its a common (yet easily fixable) error to just forget parens at the end of getter-like methods without any arguments.
The current error message for that case asks for an anonymous function, this patch adds a note asking for either an anonymous function, or for trailing parens.
This is my first contribution! do i need to do anything else?
This will enable rustdoc to treat them specially.
I also got rid of `std::cmp::cmp2`, which is isomorphic to the `TotalOrd` impl for 2-tuples and never used.
The rationale and modifications can be found in the first commit message.
This does make logging a bit more painful to use initially because it involves a feature gate and some `phase` attributes, but I think it may be reasonable to not require the `phase` attribute for loading `macro_rules!` macros because defining them will still be gated.
This commit switches over the backtrace infrastructure from piggy-backing off
the RUST_LOG environment variable to using the RUST_BACKTRACE environment
variable (logging is now disabled in libstd).
This commit starts to topographically sort rust dependencies on the linker
command line. The reason for this is that linkers use right-hand libraries to
resolve left-hand libraries symbols, which is especially crucial for us because
we're using --as-needed on linux.
In removing many fields from the crate map, executables no longer always have an
explicit dependency on all upstream libraries. This means that the linker is no
longer picking them up as it used to.
To the best of my knowledge, the current situation is happening:
* On linux, we're passing the --as-needed flag to the linker, meaning that
libraries are stripped out if there are no references to symbols in them.
* Executables may not reference libstd at all, such as "fn main() {}"
* When linking, the linker will discard libstd because there are no references
to symbols in it. I presume that this means that all previous libs have had
all their symbols resolved, so none of the libs are pulling in libstd as a
dependency.
* The only real dependence on libstd comes from the rust_stack_exhausted symbol
(which comes from libmorestack), but -lmorestack is at the end so by the time
this comes up libstd is completely gone, leading to undefined references to
rust_stack_exhausted
I'm not entirely convinced that this is what's happening, but it appears to be
along these lines. The one thing that I'm sure of is that removing the crate map
(and hence implicit dependency on all upstream libraries) has changed how
objects depend on upstream libraries.
This commit removes all internal support for the previously used __log_level()
expression. The logging subsystem was previously modified to not rely on this
magical expression. This also removes the only other function to use the
module_data map in trans, decl_gc_metadata. It appears that this is an ancient
function from a GC only used long ago.
This does not remove the crate map entirely, as libgreen still uses it to hook
in to the event loop provided by libgreen.
This commit moves all logging out of the standard library into an external
crate. This crate is the new crate which is responsible for all logging macros
and logging implementation. A few reasons for this change are:
* The crate map has always been a bit of a code smell among rust programs. It
has difficulty being loaded on almost all platforms, and it's used almost
exclusively for logging and only logging. Removing the crate map is one of the
end goals of this movement.
* The compiler has a fair bit of special support for logging. It has the
__log_level() expression as well as generating a global word per module
specifying the log level. This is unfairly favoring the built-in logging
system, and is much better done purely in libraries instead of the compiler
itself.
* Initialization of logging is much easier to do if there is no reliance on a
magical crate map being available to set module log levels.
* If the logging library can be written outside of the standard library, there's
no reason that it shouldn't be. It's likely that we're not going to build the
highest quality logging library of all time, so third-party libraries should
be able to provide just as high-quality logging systems as the default one
provided in the rust distribution.
With a migration such as this, the change does not come for free. There are some
subtle changes in the behavior of liblog vs the previous logging macros:
* The core change of this migration is that there is no longer a physical
log-level per module. This concept is still emulated (it is quite useful), but
there is now only a global log level, not a local one. This global log level
is a reflection of the maximum of all log levels specified. The previously
generated logging code looked like:
if specified_level <= __module_log_level() {
println!(...)
}
The newly generated code looks like:
if specified_level <= ::log::LOG_LEVEL {
if ::log::module_enabled(module_path!()) {
println!(...)
}
}
Notably, the first layer of checking is still intended to be "super fast" in
that it's just a load of a global word and a compare. The second layer of
checking is executed to determine if the current module does indeed have
logging turned on.
This means that if any module has a debug log level turned on, all modules
with debug log levels get a little bit slower (they all do more expensive
dynamic checks to determine if they're turned on or not).
Semantically, this migration brings no change in this respect, but
runtime-wise, this will have a perf impact on some code.
* A `RUST_LOG=::help` directive will no longer print out a list of all modules
that can be logged. This is because the crate map will no longer specify the
log levels of all modules, so the list of modules is not known. Additionally,
warnings can no longer be provided if a malformed logging directive was
supplied.
The new "hello world" for logging looks like:
#[phase(syntax, link)]
extern crate log;
fn main() {
debug!("Hello, world!");
}
This commit shreds all remnants of libextra from the compiler and standard
distribution. Two modules, c_vec/tempfile, were moved into libstd after some
cleanup, and the other modules were moved to separate crates as seen fit.
Closes#8784Closes#12413Closes#12576
I ignored AtomicU64 methods on MIPS target
because libgcc doesn't implement MIPS32 64-bit atomic operations.
Otherwise it would cause link failure.
By the way, the patched LLVM doesn't have MIPS split stack anymore.
Should I file an issue about that?
This commit shreds all remnants of libextra from the compiler and standard
distribution. Two modules, c_vec/tempfile, were moved into libstd after some
cleanup, and the other modules were moved to separate crates as seen fit.
Closes#8784Closes#12413Closes#12576
# Summary
This patch introduces the `_` token into the type grammar, with the meaning "infer this type".
With this change, the following two lines become equivalent:
```
let x = foo();
let x: _ = foo();
```
But due to its composability, it enables partial type hints like this:
```
let x: Bar<_> = baz();
```
Using it on the item level is explicitly forbidden, as the Rust language does not enable global type inference by design.
This implements the feature requested in https://github.com/mozilla/rust/issues/9508.
# Things requiring clarification
- The change to enable it is very small, but I have only limited understanding of the related code, so the approach here might be wrong.
- In particular, while this patch works, it does so in a way not originally intended according to the code comments.
- This probably needs more tests, or rather feedback for which tests are still missing.
- I'm unsure how this interacts with lifetime parameters, and whether it is correct in regard to them.
- Partial type hints on the right side of `as` like `&foo as *_` work in both a normal function contexts and in constexprs like `static foo: *int = &'static 123 as *_`. The question is whether this should be allowed in general.
# Todo for this PR
- The manual and tutorial still needs updating.
# Bugs I'm unsure how to fix
- Requesting inference for the top level of the right hand side of a `as` fails to infer correctly, even if all possible hints are given:
```
.../type_hole_1.rs:35:18: 35:22 error: the type of this value must be known in this context
.../type_hole_1.rs:35 let a: int = 1u32 as _;
^~~~
```
