The performance hit from these checks is significant, but unoptimized
builds are already incredibly slow. Enabling these checks results in
better test coverage since there are bots doing unoptimized builds, and
the cost is relatively small in the context of an unoptimized build.
This also allows using `JEMALLOC_FLAGS` to override the default
configure flags.
Its arguments were inverted.
For instance it displayed this message:
```
warning: this extern crate syntax is deprecated. Use: extern create "foobar" as foo;
```
Instead of:
```
warning: this extern crate syntax is deprecated. Use: extern create "foo" as foobar;
```
This code used to produce an ICE on the definition of trait Bar
with the following message:
Type parameter out of range when substituting in region 'a (root
type=fn(Self) -> 'astr) (space=FnSpace, index=0)
Closes#16218.
By default, 32-bit Windows executables are restricted to 2GiB of address
space even when running on 64-bit Windows when 4GiB is available.
Closes#17043
If you browse to, say, http://doc.rust-lang.org/libc/types/os/common/posix01/struct.timeval.html , you will see the "location" window showing `libc::types::os::common::posix01`. The first element points to a crate and others point modules. This patch adds the bold attribute to the first (ie. crate) element so that it stands out more.
This branch adds support for running LLVM optimization and codegen on different parts of a crate in parallel. Instead of translating the crate into a single LLVM compilation unit, `rustc` now distributes items in the crate among several compilation units, and spawns worker threads to optimize and codegen each compilation unit independently. This improves compile times on multicore machines, at the cost of worse performance in the compiled code. The intent is to speed up build times during development without sacrificing too much optimization.
On the machine I tested this on, `librustc` build time with `-O` went from 265 seconds (master branch, single-threaded) to 115s (this branch, with 4 threads), a speedup of 2.3x. For comparison, the build time without `-O` was 90s (single-threaded). Bootstrapping `rustc` using 4 threads gets a 1.6x speedup over the default settings (870s vs. 1380s), and building `librustc` with the resulting stage2 compiler takes 1.3x as long as the master branch (44s vs. 55s, single threaded, ignoring time spent in LLVM codegen).
The user-visible changes from this branch are two new codegen flags:
* `-C codegen-units=N`: Distribute items across `N` compilation units.
* `-C codegen-threads=N`: Spawn `N` worker threads for running optimization and codegen. (It is possible to set `codegen-threads` larger than `codegen-units`, but this is not very useful.)
Internal changes to the compiler are described in detail on the individual commit messages.
Note: The first commit on this branch is copied from #16359, which this branch depends on.
r? @nick29581
Sometimes (e.g. on Rust CI) the "expand description" text of the
collapse toggle was displayed by default, when a page is first
loaded (even though the description is expanded), because some
Content-Security-Policy settings disable inline CSS.
Setting it the style with the `.css` method allows the output to be used
in more places.
- Ensures the propagated negation sign is properly utilized during type
checking.
- Removed redundant type checking, specifically regarding the out of bounds checking
on a bounded type.
- Closes#16684
Adjust the handling of `#[inline]` items so that they get translated into every
compilation unit that uses them. This is necessary to preserve the semantics
of `#[inline(always)]`.
Crate-local `#[inline]` functions and statics are blindly translated into every
compilation unit. Cross-crate inlined items and monomorphizations of
`#[inline]` functions are translated the first time a reference is seen in each
compilation unit. When using multiple compilation units, inlined items are
given `available_externally` linkage whenever possible to avoid duplicating
object code.
Add a post-processing pass to `trans` that converts symbols from external to
internal when possible. Translation with multiple compilation units initially
makes most symbols external, since it is not clear when translating a
definition whether that symbol will need to be accessed from another
compilation unit. This final pass internalizes symbols that are not reachable
from other crates and not referenced from other compilation units, so that LLVM
can perform more aggressive optimizations on those symbols.
Use a shared lookup table of previously-translated monomorphizations/glue
functions to avoid translating those functions in every compilation unit where
they're used. Instead, the function will be translated in whichever
compilation unit uses it first, and the remaining compilation units will link
against that original definition.
