Implement the Cargo half of pipelined compilation (take 2)
This commit starts to lay the groundwork for #6660 where Cargo will
invoke rustc in a "pipelined" fashion. The goal here is to execute one
command to produce both an `*.rmeta` file as well as an `*.rlib` file
for candidate compilations. In that case if another rlib depends on that
compilation, then it can start as soon as the `*.rmeta` is ready and not
have to wait for the `*.rlib` compilation.
Initially attempted in #6864 with a pretty invasive refactoring this
iteration is much more lightweight and fits much more cleanly into
Cargo's backend. The approach taken here is to update the
`DependencyQueue` structure to carry a piece of data on each dependency
edge. This edge information represents the artifact that one node
requires from another, and then we a node has no outgoing edges it's
ready to build.
A dependency on a metadata file is modeled as just that, a dependency on
just the metadata and not the full build itself. Most of cargo's backend
doesn't really need to know about this edge information so it's
basically just calculated as we insert nodes into the `DependencyQueue`.
Once that's all in place it's just a few pieces here and there to
identify compilations that *can* be pipelined and then they're wired up
to depend on the rmeta file instead of the rlib file.
Closes#6660
This commit fixes an issue when pipelining mode is used in handling
recompilations. Previously a sequence of compilations could look like:
* Crate A starts to build
* Crate A produces metadata
* Crate B, which depends on A, starts
* Crate B finishes
* Crate A finishes
In this case the mtime for B is before that of A, which fooled Cargo
into thinking that B needed to be recompiled. In this case, however, B
doesn't actually need to be recompiled because it only depends on the
metadata of A, not the final artifacts.
This unfortunately resulted in some duplication in a few places, but not
really much moreso than already exists between fingerprinting and compilation.
This commit starts to lay the groundwork for #6660 where Cargo will
invoke rustc in a "pipelined" fashion. The goal here is to execute one
command to produce both an `*.rmeta` file as well as an `*.rlib` file
for candidate compilations. In that case if another rlib depends on that
compilation, then it can start as soon as the `*.rmeta` is ready and not
have to wait for the `*.rlib` compilation.
Initially attempted in #6864 with a pretty invasive refactoring this
iteration is much more lightweight and fits much more cleanly into
Cargo's backend. The approach taken here is to update the
`DependencyQueue` structure to carry a piece of data on each dependency
edge. This edge information represents the artifact that one node
requires from another, and then we a node has no outgoing edges it's
ready to build.
A dependency on a metadata file is modeled as just that, a dependency on
just the metadata and not the full build itself. Most of cargo's backend
doesn't really need to know about this edge information so it's
basically just calculated as we insert nodes into the `DependencyQueue`.
Once that's all in place it's just a few pieces here and there to
identify compilations that *can* be pipelined and then they're wired up
to depend on the rmeta file instead of the rlib file.
.. with mutliple calls of:
fastmod --accept-all '\.cargo\("([^"]+)"\)\.arg\("([^"]+)"\)' '.cargo("${1} ${2}")' tests/testsuite/
until no changes are left.
* Collapse the nested cargotest::support module into the cargotest
module (merge the mod.rs's)
* Rename the cargotest module to support
* Nest the top-level hamcrest module into support
Generally that means either switching "foo" and "bar" around (reversing
the arrow), or it means push "foo" to "bar" (and sometimes "bar" to
"baz", etc..) to free up "foo".
For trivia that leaves 80/1222 outliers, therefore 93.4% of test
project use the default. :)
By rewriting the tests, with rerast (https://github.com/google/rerast),
to use the newly introduced "at" method.
First I added the following temporary function to cargotest::support:
pub fn project_foo() -> ProjectBuilder {
project("foo")
}
Then I defined the following rewrite.rs:
use cargotest::support::{ project, project_foo };
fn rule1(a: &'static str) {
replace!(project("foo") => project_foo());
replace!(project(a) => project_foo().at(a));
}
Then I ran rerast:
cargo +nightly rerast --rules_file=rewrite.rs --force --targets tests --file tests/testsuite/main.rs
Finally I searched and replaced the references to project_foo with
argument-less project (a little awkardly on macOS with a git clean).
find tests -type f -exec sed -i -e 's/project_foo/project/g' {} +
git clean -d tests
The new `mode` for the library dependency is dependent on the library target
rather than the target which is the reason for the dependency on the library!
Closesrust-lang/rust#50640
This changes it so that only top-level targets requested on the command-line will be included in the output directory. Dependencies are no longer included.
Fixes#5444.
This hasn't been updated in awhile and in general we've been barely using it.
This drops the outdated dependency and vendors a small amount of the
functionality that it provided. I think eventually we'll want to transition away
from this method of assertions but I wanted to get this piece in to avoid too
much churn in one commit.
