It looks like this cuts down on the number of dependencies in env_logger and
notably cuts out a difference between a shared dependency of rls/cargo. My goal
here is to ensure that when we compile the RLS/Cargo on CI we only compile Cargo
once, and this is one step towards that!
This commit refactors how the path to the linker that we're going to invoke is
selected. Previously all targets listed *both* a `LinkerFlavor` and a `linker`
(path) option, but this meant that whenever you changed one you had to change
the other. The purpose of this commit is to avoid coupling these where possible.
Target specifications now only unconditionally define the *flavor* of the linker
that they're using by default. If not otherwise specified each flavor now
implies a particular default linker to run. As a result, this means that if
you'd like to test out `ld` for example you should be able to do:
rustc -Z linker-flavor=ld foo.rs
whereas previously you had to do
rustc -Z linker-flavor=ld -C linker=ld foo.rs
This will hopefully make it a bit easier to tinker around with variants that
should otherwise be well known to work, for example with LLD, `ld` on OSX, etc.
This commit imports the LLD project from LLVM to serve as the default linker for
the `wasm32-unknown-unknown` target. The `binaryen` submoule is consequently
removed along with "binaryen linker" support in rustc.
Moving to LLD brings with it a number of benefits for wasm code:
* LLD is itself an actual linker, so there's no need to compile all wasm code
with LTO any more. As a result builds should be *much* speedier as LTO is no
longer forcibly enabled for all builds of the wasm target.
* LLD is quickly becoming an "official solution" for linking wasm code together.
This, I believe at least, is intended to be the main supported linker for
native code and wasm moving forward. Picking up support early on should help
ensure that we can help LLD identify bugs and otherwise prove that it works
great for all our use cases!
* Improvements to the wasm toolchain are currently primarily focused around LLVM
and LLD (from what I can tell at least), so it's in general much better to be
on this bandwagon for bugfixes and new features.
* Historical "hacks" like `wasm-gc` will soon no longer be necessary, LLD
will [natively implement][gc] `--gc-sections` (better than `wasm-gc`!) which
means a postprocessor is no longer needed to show off Rust's "small wasm
binary size".
LLD is added in a pretty standard way to rustc right now. A new rustbuild target
was defined for building LLD, and this is executed when a compiler's sysroot is
being assembled. LLD is compiled against the LLVM that we've got in tree, which
means we're currently on the `release_60` branch, but this may get upgraded in
the near future!
LLD is placed into rustc's sysroot in a `bin` directory. This is similar to
where `gcc.exe` can be found on Windows. This directory is automatically added
to `PATH` whenever rustc executes the linker, allowing us to define a `WasmLd`
linker which implements the interface that `wasm-ld`, LLD's frontend, expects.
Like Emscripten the LLD target is currently only enabled for Tier 1 platforms,
notably OSX/Windows/Linux, and will need to be installed manually for compiling
to wasm on other platforms. LLD is by default turned off in rustbuild, and
requires a `config.toml` option to be enabled to turn it on.
Finally the unstable `#![wasm_import_memory]` attribute was also removed as LLD
has a native option for controlling this.
[gc]: https://reviews.llvm.org/D42511
This commit introduces a separately compiled backend for Emscripten, avoiding
compiling the `JSBackend` target in the main LLVM codegen backend. This builds
on the foundation provided by #47671 to create a new codegen backend dedicated
solely to Emscripten, removing the `JSBackend` of the main codegen backend in
the process.
A new field was added to each target for this commit which specifies the backend
to use for translation, the default being `llvm` which is the main backend that
we use. The Emscripten targets specify an `emscripten` backend instead of the
main `llvm` one.
There's a whole bunch of consequences of this change, but I'll try to enumerate
them here:
* A *second* LLVM submodule was added in this commit. The main LLVM submodule
will soon start to drift from the Emscripten submodule, but currently they're
both at the same revision.
* Logic was added to rustbuild to *not* build the Emscripten backend by default.
This is gated behind a `--enable-emscripten` flag to the configure script. By
default users should neither check out the emscripten submodule nor compile
it.
* The `init_repo.sh` script was updated to fetch the Emscripten submodule from
GitHub the same way we do the main LLVM submodule (a tarball fetch).
* The Emscripten backend, turned off by default, is still turned on for a number
of targets on CI. We'll only be shipping an Emscripten backend with Tier 1
platforms, though. All cross-compiled platforms will not be receiving an
Emscripten backend yet.
This commit means that when you download the `rustc` package in Rustup for Tier
1 platforms you'll be receiving two trans backends, one for Emscripten and one
that's the general LLVM backend. If you never compile for Emscripten you'll
never use the Emscripten backend, so we may update this one day to only download
the Emscripten backend when you add the Emscripten target. For now though it's
just an extra 10MB gzip'd.
Closes#46819
Building on the work of # 45684 this commit updates the compiler to
unconditionally load the `rustc_trans` crate at runtime instead of linking to it
at compile time. The end goal of this work is to implement # 46819 where rustc
will have multiple backends available to it to load.
This commit starts off by removing the `extern crate rustc_trans` from the
driver. This involved moving some miscellaneous functionality into the
`TransCrate` trait and also required an implementation of how to locate and load
the trans backend. This ended up being a little tricky because the sysroot isn't
always the right location (for example `--sysroot` arguments) so some extra code
was added as well to probe a directory relative to the current dll (the
rustc_driver dll).
Rustbuild has been updated accordingly as well to have a separate compilation
invocation for the `rustc_trans` crate and assembly it accordingly into the
sysroot. Finally, the distribution logic for the `rustc` package was also
updated to slurp up the trans backends folder.
A number of assorted fallout changes were included here as well to ensure tests
pass and such, and they should all be commented inline.
Update `rand` crate to `0.3.19`.
Update `log` crate to `0.3.9` and `0.4.1`.
Update `parking_lot_core` crate to `0.2.9`.
Upgrade all flate2 dependencies to `1.0.1`.
- Update `rust-installer` submodule.
This commit adds a new target to the compiler: wasm32-unknown-unknown. This
target is a reimagining of what it looks like to generate WebAssembly code from
Rust. Instead of using Emscripten which can bring with it a weighty runtime this
instead is a target which uses only the LLVM backend for WebAssembly and a
"custom linker" for now which will hopefully one day be direct calls to lld.
Notable features of this target include:
* There is zero runtime footprint. The target assumes nothing exists other than
the wasm32 instruction set.
* There is zero toolchain footprint beyond adding the target. No custom linker
is needed, rustc contains everything.
* Very small wasm modules can be generated directly from Rust code using this
target.
* Most of the standard library is stubbed out to return an error, but anything
related to allocation works (aka `HashMap`, `Vec`, etc).
* Naturally, any `#[no_std]` crate should be 100% compatible with this new
target.
This target is currently somewhat janky due to how linking works. The "linking"
is currently unconditional whole program LTO (aka LLVM is being used as a
linker). Naturally that means compiling programs is pretty slow! Eventually
though this target should have a linker.
This target is also intended to be quite experimental. I'm hoping that this can
act as a catalyst for further experimentation in Rust with WebAssembly. Breaking
changes are very likely to land to this target, so it's not recommended to rely
on it in any critical capacity yet. We'll let you know when it's "production
ready".
---
Currently testing-wise this target is looking pretty good but isn't complete.
I've got almost the entire `run-pass` test suite working with this target (lots
of tests ignored, but many passing as well). The `core` test suite is still
getting LLVM bugs fixed to get that working and will take some time. Relatively
simple programs all seem to work though!
---
It's worth nothing that you may not immediately see the "smallest possible wasm
module" for the input you feed to rustc. For various reasons it's very difficult
to get rid of the final "bloat" in vanilla rustc (again, a real linker should
fix all this). For now what you'll have to do is:
cargo install --git https://github.com/alexcrichton/wasm-gc
wasm-gc foo.wasm bar.wasm
And then `bar.wasm` should be the smallest we can get it!
---
In any case for now I'd love feedback on this, particularly on the various
integration points if you've got better ideas of how to approach them!
This affects regular code generation as well as constant evaluation in trans,
but not the HIR constant evaluator because that one returns an error for
overflowing casts and NaN-to-int casts. That error is conservatively
correct and we should be careful to not accept more code in constant
expressions.
The changes to code generation are guarded by a new -Z flag, to be able
to evaluate the performance impact. The trans constant evaluation changes
are unconditional because they have no run time impact and don't affect
type checking either.
This PR is an implementation of [RFC 1974] which specifies a new method of
defining a global allocator for a program. This obsoletes the old
`#![allocator]` attribute and also removes support for it.
[RFC 1974]: https://github.com/rust-lang/rfcs/pull/197
The new `#[global_allocator]` attribute solves many issues encountered with the
`#![allocator]` attribute such as composition and restrictions on the crate
graph itself. The compiler now has much more control over the ABI of the
allocator and how it's implemented, allowing much more freedom in terms of how
this feature is implemented.
cc #27389
This commit integrates the `jobserver` crate into the compiler. The crate was
previously integrated in to Cargo as part of rust-lang/cargo#4110. The purpose
here is to two-fold:
* Primarily the compiler can cooperate with Cargo on parallelism. When you run
`cargo build -j4` then this'll make sure that the entire build process between
Cargo/rustc won't use more than 4 cores, whereas today you'd get 4 rustc
instances which may all try to spawn lots of threads.
* Secondarily rustc/Cargo can now integrate with a foreign GNU `make` jobserver.
This means that if you call cargo/rustc from `make` or another
jobserver-compatible implementation it'll use foreign parallelism settings
instead of creating new ones locally.
As the number of parallel codegen instances in the compiler continues to grow
over time with the advent of incremental compilation it's expected that this'll
become more of a problem, so this is intended to nip concurrent concerns in the
bud by having all the tools to cooperate!
Note that while rustc has support for itself creating a jobserver it's far more
likely that rustc will always use the jobserver configured by Cargo. Cargo today
will now set a jobserver unconditionally for rustc to use.
A long time coming this commit removes the `flate` crate in favor of the
`flate2` crate on crates.io. The functionality in `flate2` originally flowered
out of `flate` itself and is additionally the namesake for the crate. This will
leave a gap in the naming (there's not `flate` crate), which will likely cause a
particle collapse of some form somewhere.
Move the code for loading metadata from rlibs and dylibs from
rustc_metadata into rustc_trans, and introduce a trait to avoid
introducing a direct dependency on rustc_trans.
This means rustc_metadata is no longer rebuilt when LLVM changes.
This commit deletes the internal liblog in favor of the implementation that
lives on crates.io. Similarly it's also setting a convention for adding crates
to the compiler. The main restriction right now is that we want compiler
implementation details to be unreachable from normal Rust code (e.g. requires a
feature), and by default everything in the sysroot is reachable via `extern
crate`.
The proposal here is to require that crates pulled in have these lines in their
`src/lib.rs`:
#![cfg_attr(rustbuild, feature(staged_api, rustc_private))]
#![cfg_attr(rustbuild, unstable(feature = "rustc_private", issue = "27812"))]
This'll mean that by default they're not using these attributes but when
compiled as part of the compiler they do a few things:
* Mark themselves as entirely unstable via the `staged_api` feature and the
`#![unstable]` attribute.
* Allow usage of other unstable crates via `feature(rustc_private)` which is
required if the crate relies on any other crates to compile (other than std).
It claims to accept most GNU linker options, but in fact most of them
have no effect and instead it requires some special options which are
easier to handle in a separate trait.
Currently added:
- `export_symbols`: works on executables as special Emscripten case
since staticlibs/dylibs aren't compiled to JS, while exports are
required to be accessible from JS.
Fixes#39171.
- `optimize` - translates Rust's optimization level to Emscripten
optimization level (whether passed via `-C opt-level=...` or `-O...`).
Fixes#36899.
- `debuginfo` - translates debug info; Emscripten has 5 debug levels
while Rust has 3, so chose to translate `-C debuginfo=1` to `-g3`
(preserves whitespace, variable and function names for easy debugging).
Fixes#36901.
- `no_default_libraries` - tells Emscripten to exlude `memcpy` and co.
This commit updates the version number to 1.17.0 as we're not on that version of
the nightly compiler, and at the same time this updates src/stage0.txt to
bootstrap from freshly minted beta compiler and beta Cargo.
This commit introduces 128-bit integers. Stage 2 builds and produces a working compiler which
understands and supports 128-bit integers throughout.
The general strategy used is to have rustc_i128 module which provides aliases for iu128, equal to
iu64 in stage9 and iu128 later. Since nowhere in rustc we rely on large numbers being supported,
this strategy is good enough to get past the first bootstrap stages to end up with a fully working
128-bit capable compiler.
In order for this strategy to work, number of locations had to be changed to use associated
max_value/min_value instead of MAX/MIN constants as well as the min_value (or was it max_value?)
had to be changed to use xor instead of shift so both 64-bit and 128-bit based consteval works
(former not necessarily producing the right results in stage1).
This commit includes manual merge conflict resolution changes from a rebase by @est31.
The librustc_llvm API remains mostly unchanged, except that llvm::Attribute is no longer a bitflag but represents only a *single* attribute.
The ability to store many attributes in a small number of bits and modify them without interacting with LLVM is only used in rustc_trans::abi and closely related modules, and only attributes for function arguments are considered there.
Thus rustc_trans::abi now has its own bit-packed representation of argument attributes, which are translated to rustc_llvm::Attribute when applying the attributes.
This commit adds support to rustbuild to run crate unit tests (those defined by
`#[test]`) as well as documentation tests. All tests are powered by `cargo test`
under the hood.
Each step requires the `libtest` library is built for that corresponding stage.
Ideally the `test` crate would be a dev-dependency, but for now it's just easier
to ensure that we sequence everything in the right order.
Currently no filtering is implemented, so there's not actually a method of
testing *only* libstd or *only* libcore, but rather entire swaths of crates are
tested all at once.
A few points of note here are:
* The `coretest` and `collectionstest` crates are just listed as `[[test]]`
entires for `cargo test` to naturally pick up. This mean that `cargo test -p
core` actually runs all the tests for libcore.
* Libraries that aren't tested all mention `test = false` in their `Cargo.toml`
* Crates aren't currently allowed to have dev-dependencies due to
rust-lang/cargo#860, but we can likely alleviate this restriction once
workspaces are implemented.
cc #31590
rustbuild: Fix dist for non-host targets
The `rust-std` package that we produce is expected to have not only the standard
library but also libtest for compiling unit tests. Unfortunately this does not
currently happen due to the way rustbuild is structured.
There are currently two main stages of compilation in rustbuild, one for the
standard library and one for the compiler. This is primarily done to allow us to
fill in the sysroot right after the standard library has finished compiling to
continue compiling the rest of the crates. Consequently the entire compiler does
not have to explicitly depend on the standard library, and this also should
allow us to pull in crates.io dependencies into the build in the future because
they'll just naturally build against the std we just produced.
These phases, however, do not represent a cross-compiled build. Target-only
builds also require libtest, and libtest is currently part of the
all-encompassing "compiler build". There's unfortunately no way to learn about
just libtest and its dependencies (in a great and robust fashion) so to ensure
that we can copy the right artifacts over this commit introduces a new build
step, libtest.
The new libtest build step has documentation, dist, and link steps as std/rustc
already do. The compiler now depends on libtest instead of libstd, and all
compiler crates can now assume that test and its dependencies are implicitly
part of the sysroot (hence explicit dependencies being removed). This makes the
build a tad less parallel as in theory many rustc crates can be compiled in
parallel with libtest, but this likely isn't where we really need parallelism
either (all the time is still spent in the compiler).
All in all this allows the `dist-std` step to depend on both libstd and libtest,
so `rust-std` packages produced by rustbuild should start having both the
standard library and libtest.
Closes#32523
The `rust-std` package that we produce is expected to have not only the standard
library but also libtest for compiling unit tests. Unfortunately this does not
currently happen due to the way rustbuild is structured.
There are currently two main stages of compilation in rustbuild, one for the
standard library and one for the compiler. This is primarily done to allow us to
fill in the sysroot right after the standard library has finished compiling to
continue compiling the rest of the crates. Consequently the entire compiler does
not have to explicitly depend on the standard library, and this also should
allow us to pull in crates.io dependencies into the build in the future because
they'll just naturally build against the std we just produced.
These phases, however, do not represent a cross-compiled build. Target-only
builds also require libtest, and libtest is currently part of the
all-encompassing "compiler build". There's unfortunately no way to learn about
just libtest and its dependencies (in a great and robust fashion) so to ensure
that we can copy the right artifacts over this commit introduces a new build
step, libtest.
The new libtest build step has documentation, dist, and link steps as std/rustc
already do. The compiler now depends on libtest instead of libstd, and all
compiler crates can now assume that test and its dependencies are implicitly
part of the sysroot (hence explicit dependencies being removed). This makes the
build a tad less parallel as in theory many rustc crates can be compiled in
parallel with libtest, but this likely isn't where we really need parallelism
either (all the time is still spent in the compiler).
All in all this allows the `dist-std` step to depend on both libstd and libtest,
so `rust-std` packages produced by rustbuild should start having both the
standard library and libtest.
Closes#32523
