The same test was missed in chan/port renaming PR #12815 and was fixed in #12880:
> This was missed because it is skipped on linux and windows, and the mac bots were moving at the time the PR landed.
It seems the same happened to the liblog PR.
This is a minor optimization of the bignum module. The improvements mostly come from avoiding allocations and boundary checks. This also switches all of libnum to vec_ng::Vec.
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.
After `make clean` I'm seeing the build break with
```
cp: cannot stat ‘x86_64-unknown-linux-gnu/rt/libbacktrace/.libs/libbacktrace.a’: No such file or directory
```
Deleteing the libbacktrace dir entirely on clean fixes.
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!");
}
After `make clean' I'm seeing the build break with
```
cp: cannot stat ‘x86_64-unknown-linux-gnu/rt/libbacktrace/.libs/libbacktrace.a’: No such file or directory
```
Deleteing the libbacktrace dir entirely on clean fixes.
This is mostly just an implementation detail, and anyone worried about the stack
bounds doesn't need to be bothered with the red zone because it's not usable
anyway.
Closes#12897
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
This is mostly just an implementation detail, and anyone worried about the stack
bounds doesn't need to be bothered with the red zone because it's not usable
anyway.
Closes#12897
docs: begin a "low-level & unsafe code" guide.
This aims to cover the basics of writing safe unsafe code. At the moment
it is just designed to be a better place for the `asm!()` docs than the
detailed release notes wiki page, and I took the time to write up some
other things.
More examples are needed, especially of things that can subtly go wrong;
and vast areas of `unsafe`-ty aren't covered, e.g. `static mut`s and
thread-safety in general.
This aims to cover the basics of writing safe unsafe code. At the moment
it is just designed to be a better place for the `asm!()` docs than the
detailed release notes wiki page, and I took the time to write up some
other things.
More examples are needed, especially of things that can subtly go wrong;
and vast areas of `unsafe`-ty aren't covered, e.g. `static mut`s and
thread-safety in general.
The old comment of as_mut_slice() did not describe the function correctly. The new one does.
Also refactored option::iter() and option::mut_iter() to use as_ref() and as_mut() instead of match.
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
The `Float` trait provides correct `min` and `max` methods on floating
point types, providing a consistent result regardless of the order the
parameters are passed.
These generic functions do not take the necessary performance hit to
correctly support a partial order, so the true requirement should be
given as a type bound.
Closes#12712
The `Float` trait provides correct `min` and `max` methods on floating
point types, providing a consistent result regardless of the order the
parameters are passed.
These generic functions do not take the necessary performance hit to
correctly support a partial order, so the true requirement should be
given as a type bound.
Closes#12712
On android, libgcc is missing the _Unwind_GetIP symbol because it's defined as a
macro. This is the same case for arm linux, so this commit adds the necessary
cfgs in place to use the "expanded macro" in rust for arm linux.
Previously, the cfg attribute `cfg(not(a, b))` was translated to `(!a && !b)`,
but this isn't very useful because that can already be expressed as
`cfg(not(a), not(b))`. This commit changes the translation to `!(a && b)` which
is more symmetrical of the rest of the `cfg` attribute.
Put another way, I would expect `cfg(clause)` to be the opposite of
`cfg(not(clause))`, but this is not currently the case with multiple element
clauses.
