This commit adds a new wasm32-based target distributed through rustup,
supported in the standard library, and implemented in the compiler. The
`wasm32-unknown-wasi` target is intended to be a WebAssembly target
which matches the [WASI proposal recently announced.][LINK]. In summary
the WASI target is an effort to define a standard set of syscalls for
WebAssembly modules, allowing WebAssembly modules to not only be
portable across architectures but also be portable across environments
implementing this standard set of system calls.
The wasi target in libstd is still somewhat bare bones. This PR does not
fill out the filesystem, networking, threads, etc. Instead it only
provides the most basic of integration with the wasi syscalls, enabling
features like:
* `Instant::now` and `SystemTime::now` work
* `env::args` is hooked up
* `env::vars` will look up environment variables
* `println!` will print to standard out
* `process::{exit, abort}` should be hooked up appropriately
None of these APIs can work natively on the `wasm32-unknown-unknown`
target, but with the assumption of the WASI set of syscalls we're able
to provide implementations of these syscalls that engines can implement.
Currently the primary engine implementing wasi is [wasmtime], but more
will surely emerge!
In terms of future development of libstd, I think this is something
we'll probably want to discuss. The purpose of the WASI target is to
provide a standardized set of syscalls, but it's *also* to provide a
standard C sysroot for compiling C/C++ programs. This means it's
intended that functions like `read` and `write` are implemented for this
target with a relatively standard definition and implementation. It's
unclear, therefore, how we want to expose file descriptors and how we'll
want to implement system primitives. For example should `std::fs::File`
have a libc-based file descriptor underneath it? The raw wasi file
descriptor? We'll see! Currently these details are all intentionally
hidden and things we can change over time.
A `WasiFd` sample struct was added to the standard library as part of
this commit, but it's not currently used. It shows how all the wasi
syscalls could be ergonomically bound in Rust, and they offer a possible
implementation of primitives like `std::fs::File` if we bind wasi file
descriptors exactly.
Apart from the standard library, there's also the matter of how this
target is integrated with respect to its C standard library. The
reference sysroot, for example, provides managment of standard unix file
descriptors and also standard APIs like `open` (as opposed to the
relative `openat` inspiration for the wasi ssycalls). Currently the
standard library relies on the C sysroot symbols for operations such as
environment management, process exit, and `read`/`write` of stdio fds.
We want these operations in Rust to be interoperable with C if they're
used in the same process. Put another way, if Rust and C are linked into
the same WebAssembly binary they should work together, but that requires
that the same C standard library is used.
We also, however, want the `wasm32-unknown-wasi` target to be
usable-by-default with the Rust compiler without requiring a separate
toolchain to get downloaded and configured. With that in mind, there's
two modes of operation for the `wasm32-unknown-wasi` target:
1. By default the C standard library is statically provided inside of
`liblibc.rlib` distributed as part of the sysroot. This means that
you can `rustc foo.wasm --target wasm32-unknown-unknown` and you're
good to go, a fully workable wasi binary pops out. This is
incompatible with linking in C code, however, which may be compiled
against a different sysroot than the Rust code was previously
compiled against. In this mode the default of `rust-lld` is used to
link binaries.
2. For linking with C code, the `-C target-feature=-crt-static` flag
needs to be passed. This takes inspiration from the musl target for
this flag, but the idea is that you're no longer using the provided
static C runtime, but rather one will be provided externally. This
flag is intended to also get coupled with an external `clang`
compiler configured with its own sysroot. Therefore you'll typically
use this flag with `-C linker=/path/to/clang-script-wrapper`. Using
this mode the Rust code will continue to reference standard C
symbols, but the definition will be pulled in by the linker configured.
Alright so that's all the current state of this PR. I suspect we'll
definitely want to discuss this before landing of course! This PR is
coupled with libc changes as well which I'll be posting shortly.
[LINK]:
[wasmtime]:
replace llvm-rebuild-trigger with submodule commit hash
As mentioned in #59285.
This PR removes the need to update the `llvm-rebuild-trigger` file. Instead, the latest commit hash of the appropriate LLVM submodule will be stored in the stamp file and used to detect if a build is required.
Fixes#42405.
Fixes#54959.
Fixes#55537.
bootstrap: build crates under libtest with -Z emit-stack-sizes
Please see the comment in the diff for the rationale.
This change adds a `.stack_sizes` linker section to `libcompiler_builtins.rlib`
but this section is discarded by the linker by default so it won't affect the
binary size of most programs. It will, however, negatively affect the binary
size of programs that link to a recent release of the `cortex-m-rt` crate
because of the linker script that crate provides, but I have proposed a PR
(rust-embedded/cortex-m-rt#186) to solve the problem (which I originally
introduced :-)).
This change does increase the size of the `libcompiler_builtins.rlib` artifact we
distribute but the increase is in the order of (a few) KBs.
r? @alexcrichton
Add a way to track Rustfix UI test coverage
This came out of the first Rustfix WG meeting.
One of the goals is to enable Rustfix tests for all UI tests that
trigger lints with `MachineApplicable` suggestions. In order to do that
we first want to create a tracking issue that lists all files with
missing `// run-rustfix` headers.
This PR adds a `--rustfix-coverage` flag to `./x.py` and compiletest to
list the files with the missing headers in `/tmp/rustfix_missing_coverage.txt`.
From that file we can create the tracking issue and at some point also
enforce the `// run-rustfix` flag on UI tests with `MachineApplicable`
lints.
Include llvm-ar with llvm-tools component
Adds the `llvm-ar` tool to the `llvm-tools` component. This is useful for [building and linking native code](https://doc.rust-lang.org/cargo/reference/build-scripts.html#case-study-building-some-native-code) in cargo build scripts without needing to use the platform specific `ar`. According to #58663 it is also useful for WASM.
`llvm-ar` is very small (~82KB), so it does not significantly increase the size of the `llvm-tools` component.
Fixes#58663
Exclude old book redirect stubs from search engines
Adds `<meta name="robots" content="noindex,follow">` to the `<head>` of old stub pages pointing to the second edition of the book.
This is continuation of https://github.com/rust-lang/book/pull/1788
This came out of the first Rustfix WG meeting.
One of the goals is to enable Rustfix tests for all UI tests that
trigger lints with `MachineApplicable` suggestions. In order to do that
we first want to create a tracking issue that lists all files with
missing `// run-rustfix` headers.
This PR adds a `--rustfix-coverage` flag to `./x.py` and compiletest to
list the files with the missing headers in `/tmp/rustfix_missing_coverage.txt`.
From that file we can create the tracking issue and at some point also
enforce the `// run-rustfix` flag on UI tests with `MachineApplicable`
lints.
Rework how bootstrap tools are built
This makes bootstrap tools buildable and testable in stage 0 with the downloaded bootstrap compiler, futhermore, it makes it such that they cannot be built in any other stage.
Notably, this will also mean that compiletest may need to wait a cycle before it can use changes to `libtest`, as it no longer depends on the in-tree libtest.
Introduce assembly tests suite
The change introduces a new test suite - **Assembly** tests. The motivation behind this is an ability to perform end-to-end codegen testing with LLVM backend. Turned out, NVPTX backend sometimes missing common Rust features (`i128` and libcalls in the past, and still full atomics support) due to different reasons.
Prior to this change, basic NVPTX assembly tests were implemented within `run-make` suite. Now, it's easier to write additional and maintain existing tests for the target.
cc @gnzlbg @peterhj
cc @eddyb I adjusted mangling scheme expectation, so there is no need to change the tests for #57967
bootstrap: Default to a sensible llvm-suffix.
I used version-channel-sha, hopefully that should work.
I checked that bootstrap builds, but I cannot check anything else since the llvm
build process is started from cargo, and thus calls clang, and thus I hit the
same bug I hope to fix with this change.
Hopefully fixes#59034.
I used version-channel-sha, hopefully that should work.
I checked that bootstrap builds, but I cannot check anything else since the llvm
build process is started from cargo, and thus calls clang, and thus I hit the
same bug I hope to fix with this change.
Hopefully fixes#59034.
look for python2 symlinks before bootstrap python
Before this commit, if you're running x.py directly on a system where
`python` is symlinked to Python 3, then the `python` config option will
default to a Python 3 interpreter. This causes debuginfo tests to fail
with an opaque error message, since they have a hard requirement on
Python 2.
This commit modifies the Python probe behavior to look for python2.7 and
python2 *before* using the interpreter used to execute `x.py`.
