Right now this directory is located under:
$sysroot/lib/rustlib/$target/lib/codegen-backends
but after seeing what we do in a few other places it seems that a more
appropriate location would be:
$sysroot/lib/rustlib/$target/codegen-backends
so this commit moves it!
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.
Remove broken redundant backtrace hint
When the compiler driver panics it attempts to show a hint about using `RUST_BACKTRACE`. However, the logic is currently reversed to the hint is only shown if `RUST_BACKTRACE` is **already** set:
```shell
> RUST_BACKTRACE=1 rustc /dev/null --crate-type proc-macro
error: internal compiler error: unexpected panic
...
note: run with `RUST_BACKTRACE=1` for a backtrace
thread 'rustc' panicked at 'attempt to subtract with overflow', librustc_errors/emitter.rs:287:49
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
> RUST_BACKTRACE=0 rustc /dev/null --crate-type proc-macro
error: internal compiler error: unexpected panic
...
thread 'rustc' panicked at 'attempt to subtract with overflow', librustc_errors/emitter.rs:287:49
note: Run with `RUST_BACKTRACE=1` for a backtrace.
```
As the `panic` itself already has a working `RUST_BACKTRACE` hint just remove the broken duplicate hint entirely.
When the compiler driver panics it attempts to show a hint about using
`RUST_BACKTRACE`. However, the logic is currently reversed to the hint
is only shown if `RUST_BACKTRACE` is *already* set:
```shell
> RUST_BACKTRACE=1 rustc /dev/null --crate-type proc-macro
error: internal compiler error: unexpected panic
...
note: run with `RUST_BACKTRACE=1` for a backtrace
thread 'rustc' panicked at 'attempt to subtract with overflow', librustc_errors/emitter.rs:287:49
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
> RUST_BACKTRACE=0 rustc /dev/null --crate-type proc-macro
error: internal compiler error: unexpected panic
...
thread 'rustc' panicked at 'attempt to subtract with overflow', librustc_errors/emitter.rs:287:49
note: Run with `RUST_BACKTRACE=1` for a backtrace.
```
As the `panic` itself already has a working `RUST_BACKTRACE` hint just
remove the broken duplicate hint entirely.
Change the --unpretty flag to -Z unpretty
First PR 😄 !
-Z unpretty no longer requires -Z unstable-options.
Also, I mildly changed the syntax of the flag to match the other -Z flags. All uses of the flag take the form `unpretty=something` where something can either `string` or `string=string` (see the help messages of the CLI).
Fix#47395
r? @nikomatsakis EDIT: apparently rust-highfive doesn't see edits...
-Z unpretty no longer requires -Z unstable-options. Also, I mildly
changed the syntax of the flag to match the other -Z flags. All uses of
the flag take the form `unpretty=something` where something can either
`string` or `string=string` (see the help messages of the CLI).
rustc: Tweak `#[target_feature]` syntax
This is an implementation of the `#[target_feature]` syntax-related changes of
[RFC 2045][rfc]. Notably two changes have been implemented:
* The new syntax is `#[target_feature(enable = "..")]` instead of
`#[target_feature = "+.."]`. The `enable` key is necessary instead of the `+`
to indicate that a feature is being enabled, and a sub-list is used for
possible expansion in the future. Additionally within this syntax the feature
names being enabled are now whitelisted against a known set of target feature
names that we know about.
* The `#[target_feature]` attribute can only be applied to unsafe functions. It
was decided in the RFC that invoking an instruction possibly not defined for
the current processor is undefined behavior, so to enable this feature for now
it requires an `unsafe` intervention.
[rfc]: https://github.com/rust-lang/rfcs/blob/master/text/2045-target-feature.md
No longer parse it.
Remove AutoTrait variant from AST and HIR.
Remove backwards compatibility lint.
Remove coherence checks, they make no sense for the new syntax.
Remove from rustdoc.
Add -Ztime-passes line for dep-graph loading.
We measure how much time the background thread spends on loading the dep-graph but not how long the main thread is blocked while the background thread is still working. Let's change that!
Do not emit type errors on recovered blocks
When a parse error occurs on a block, the parser will recover and create
a block with the statements collected until that point. Now a flag
stating that a recovery has been performed in this block is propagated
so that the type checker knows that the type of the block (which will be
identified as `()`) shouldn't be checked against the expectation to
reduce the amount of irrelevant diagnostic errors shown to the user.
Fix#44579.
When a parse error occurs on a block, the parser will recover and create
a block with the statements collected until that point. Now a flag
stating that a recovery has been performed in this block is propagated
so that the type checker knows that the type of the block (which will be
identified as `()`) shouldn't be checked against the expectation to
reduce the amount of irrelevant diagnostic errors shown to the user.
Prevent rustc overwriting input files
If rustc is invoked on a file that would be overwritten by the
compilation, the compilation now fails, to avoid accidental loss. This
resolves#13019. Kudos to @estebank, whose patch I finished off.
