Merge from rustc

BoxyUwU · BoxyUwU · commit b98da0d8e3ff · 2025-01-28T11:57:19.000Z
diff --git a/examples/rustc-driver-example.rs b/examples/rustc-driver-example.rs
@@ -18,8 +18,8 @@ use std::path::Path;
 
 use rustc_ast_pretty::pprust::item_to_string;
 use rustc_data_structures::sync::Lrc;
-use rustc_driver::{Compilation, RunCompiler};
-use rustc_interface::interface::Compiler;
+use rustc_driver::{Compilation, run_compiler};
+use rustc_interface::interface::{Compiler, Config};
 use rustc_middle::ty::TyCtxt;
 
 struct MyFileLoader;
@@ -51,6 +51,10 @@ fn main() {
 struct MyCallbacks;
 
 impl rustc_driver::Callbacks for MyCallbacks {
+    fn config(&mut self, config: &mut Config) {
+        config.file_loader = Some(Box::new(MyFileLoader));
+    }
+
     fn after_crate_root_parsing(
         &mut self,
         _compiler: &Compiler,
@@ -83,10 +87,5 @@ impl rustc_driver::Callbacks for MyCallbacks {
 }
 
 fn main() {
-    match RunCompiler::new(&["main.rs".to_string()], &mut MyCallbacks) {
-        mut compiler => {
-            compiler.set_file_loader(Some(Box::new(MyFileLoader)));
-            compiler.run();
-        }
-    }
+    run_compiler(&["main.rs".to_string()], &mut MyCallbacks);
 }
diff --git a/examples/rustc-driver-interacting-with-the-ast.rs b/examples/rustc-driver-interacting-with-the-ast.rs
@@ -18,8 +18,8 @@ use std::path::Path;
 
 use rustc_ast_pretty::pprust::item_to_string;
 use rustc_data_structures::sync::Lrc;
-use rustc_driver::{Compilation, RunCompiler};
-use rustc_interface::interface::Compiler;
+use rustc_driver::{Compilation, run_compiler};
+use rustc_interface::interface::{Compiler, Config};
 use rustc_middle::ty::TyCtxt;
 
 struct MyFileLoader;
@@ -51,6 +51,10 @@ fn main() {
 struct MyCallbacks;
 
 impl rustc_driver::Callbacks for MyCallbacks {
+    fn config(&mut self, config: &mut Config) {
+        config.file_loader = Some(Box::new(MyFileLoader));
+    }
+
     fn after_crate_root_parsing(
         &mut self,
         _compiler: &Compiler,
@@ -90,10 +94,5 @@ impl rustc_driver::Callbacks for MyCallbacks {
 }
 
 fn main() {
-    match RunCompiler::new(&["main.rs".to_string()], &mut MyCallbacks) {
-        mut compiler => {
-            compiler.set_file_loader(Some(Box::new(MyFileLoader)));
-            compiler.run();
-        }
-    }
+    run_compiler(&["main.rs".to_string()], &mut MyCallbacks);
 }
diff --git a/src/building/bootstrapping/debugging-bootstrap.md b/src/building/bootstrapping/debugging-bootstrap.md
@@ -1,6 +1,6 @@
 # Debugging bootstrap
 
-> FIXME: this page could be expanded 
+> FIXME: this section should be expanded
 
 ## `tracing` in bootstrap
 
@@ -10,21 +10,69 @@ Bootstrap has conditional [`tracing`][tracing] setup to provide structured loggi
 
 ### Enabling `tracing` output
 
-Bootstrap will conditionally enable `tracing` output if the `BOOTSTRAP_TRACING` env var is set.
+Bootstrap will conditionally build `tracing` support and enable `tracing` output if the `BOOTSTRAP_TRACING` env var is set.
 
-Example usage:
+#### Basic usage
+
+Example basic usage[^just-trace]:
+
+[^just-trace]: It is not recommend to use *just* `BOOTSTRAP_TRACING=TRACE` because that will dump *everything* at `TRACE` level, including logs intentionally gated behind custom targets as they are too verbose even for `TRACE` level by default.
 
 ```bash
-$ BOOTSTRAP_TRACING=TRACE ./x build library --stage 1
+$ BOOTSTRAP_TRACING=bootstrap=TRACE ./x build library --stage 1
+```
+
+Example output[^unstable]:
+
+```
+$ BOOTSTRAP_TRACING=bootstrap=TRACE ./x check src/bootstrap/
+Building bootstrap
+   Compiling bootstrap v0.0.0 (/home/joe/repos/rust/src/bootstrap)
+    Finished `dev` profile [unoptimized] target(s) in 2.74s
+ DEBUG bootstrap parsing flags
+ bootstrap::core::config::flags::Flags::parse args=["check", "src/bootstrap/"]
+ DEBUG bootstrap parsing config based on flags
+ DEBUG bootstrap creating new build based on config
+ bootstrap::Build::build
+  TRACE bootstrap setting up job management
+  TRACE bootstrap downloading rustfmt early
+   bootstrap::handling hardcoded subcommands (Format, Suggest, Perf)
+    DEBUG bootstrap not a hardcoded subcommand; returning to normal handling, cmd=Check { all_targets: false }
+  DEBUG bootstrap handling subcommand normally
+   bootstrap::executing real run
+     bootstrap::(1) executing dry-run sanity-check
+     bootstrap::(2) executing actual run
+Checking stage0 library artifacts (x86_64-unknown-linux-gnu)
+    Finished `release` profile [optimized + debuginfo] target(s) in 0.04s
+Checking stage0 compiler artifacts {rustc-main, rustc_abi, rustc_arena, rustc_ast, rustc_ast_ir, rustc_ast_lowering, rustc_ast_passes, rustc_ast_pretty, rustc_attr_data_structures, rustc_attr_parsing, rustc_baked_icu_data, rustc_borrowck, rustc_builtin_macros, rustc_codegen_llvm, rustc_codegen_ssa, rustc_const_eval, rustc_data_structures, rustc_driver, rustc_driver_impl, rustc_error_codes, rustc_error_messages, rustc_errors, rustc_expand, rustc_feature, rustc_fluent_macro, rustc_fs_util, rustc_graphviz, rustc_hir, rustc_hir_analysis, rustc_hir_pretty, rustc_hir_typeck, rustc_incremental, rustc_index, rustc_index_macros, rustc_infer, rustc_interface, rustc_lexer, rustc_lint, rustc_lint_defs, rustc_llvm, rustc_log, rustc_macros, rustc_metadata, rustc_middle, rustc_mir_build, rustc_mir_dataflow, rustc_mir_transform, rustc_monomorphize, rustc_next_trait_solver, rustc_parse, rustc_parse_format, rustc_passes, rustc_pattern_analysis, rustc_privacy, rustc_query_impl, rustc_query_system, rustc_resolve, rustc_sanitizers, rustc_serialize, rustc_session, rustc_smir, rustc_span, rustc_symbol_mangling, rustc_target, rustc_trait_selection, rustc_traits, rustc_transmute, rustc_ty_utils, rustc_type_ir, rustc_type_ir_macros, stable_mir} (x86_64-unknown-linux-gnu)
+    Finished `release` profile [optimized + debuginfo] target(s) in 0.23s
+Checking stage0 bootstrap artifacts (x86_64-unknown-linux-gnu)
+    Checking bootstrap v0.0.0 (/home/joe/repos/rust/src/bootstrap)
+    Finished `release` profile [optimized + debuginfo] target(s) in 0.64s
+  DEBUG bootstrap checking for postponed test failures from `test  --no-fail-fast`
+Build completed successfully in 0:00:08
 ```
 
-Example output[^experimental]:
+#### Controlling log output
+
+The env var `BOOTSTRAP_TRACING` accepts a [`tracing` env-filter][tracing-env-filter].
+
+There are two orthogonal ways to control which kind of logs you want:
 
-![Example bootstrap tracing output](./debugging-bootstrap/tracing-output-example.png)
+1. You can specify the log **level**, e.g. `DEBUG` or `TRACE`.
+2. You can also control the log **target**, e.g. `bootstrap` or `bootstrap::core::config` vs custom targets like `CONFIG_HANDLING`.
+    - Custom targets are used to limit what is output when `BOOTSTRAP_TRACING=bootstrap=TRACE` is used, as they can be too verbose even for `TRACE` level by default. Currently used custom targets:
+        - `CONFIG_HANDLING`
 
-[^experimental]: This shows what's *possible* with the infra in an experimental implementation.
+The `TRACE` filter will enable *all* `trace` level or less verbose level tracing output.
 
-The env var `BOOTSTRAP_TRACING` accepts a [`tracing` env-filter][tracing-env-filter]. The `TRACE` filter will enable *all* `trace` level or less verbose level tracing output.
+You can of course combine them (custom target logs are typically gated behind `TRACE` log level additionally):
+
+```bash
+$ BOOTSTRAP_TRACING=CONFIG_HANDLING=TRACE ./x build library --stage 1
+```
+
+[^unstable]: This output is always subject to further changes.
 
 [tracing-env-filter]: https://docs.rs/tracing-subscriber/0.3.19/tracing_subscriber/filter/struct.EnvFilter.html
 
@@ -73,28 +121,6 @@ For `#[instrument]`, it's recommended to:
 - Explicitly pick an instrumentation name via `name = ".."` to distinguish between e.g. `run` of different steps.
 - Take care to not cause diverging behavior via tracing, e.g. building extra things only when tracing infra is enabled.
 
-### Enabling `tracing` bootstrap feature in rust-analyzer
+### rust-analyzer integration?
 
-You can adjust your `settings.json`'s `rust-analyzer.check.overrideCommand` and `rust-analyzer.cargo.buildScripts.overrideCommand` if you want to also enable `logging` cargo feature by default in your editor. This is mostly useful if you want proper r-a completions and such when working on bootstrap itself.
-
-```json
-"rust-analyzer.check.overrideCommand": [
-    "BOOTSTRAP_TRACING=1", // <- BOOTSTRAP_TRACING=1 won't enable tracing filter, but it will activate bootstrap's `tracing` feature
-    "python3",
-    "x.py",
-    "check",
-    "--json-output",
-    "--build-dir=build-rust-analyzer"
-],
-```
-
-```json
-"rust-analyzer.cargo.buildScripts.overrideCommand": [
-    "BOOTSTRAP_TRACING=1", // <- note this
-    "python3",
-    "x.py",
-    "check",
-    "--json-output",
-    "--build-dir=build-rust-analyzer"
-],
-```
+Unfortunately, because bootstrap is a `rust-analyzer.linkedProjects`, you can't ask r-a to check/build bootstrap itself with `tracing` feature enabled to get relevant completions, due to lack of support as described in <https://github.com/rust-lang/rust-analyzer/issues/8521>.
diff --git a/src/building/bootstrapping/debugging-bootstrap/tracing-output-example.png b/src/building/bootstrapping/debugging-bootstrap/tracing-output-example.png
diff --git a/src/conventions.md b/src/conventions.md
@@ -1,4 +1,4 @@
-This file offers some tips on the coding conventions for rustc.  This
+This file offers some tips on the coding conventions for rustc. This
 chapter covers [formatting](#formatting), [coding for correctness](#cc),
 [using crates from crates.io](#cio), and some tips on
 [structuring your PR for easy review](#er).
@@ -25,6 +25,7 @@ pass the <!-- date-check: nov 2022 --> `--edition=2021` argument yourself when c
 `rustfmt` directly.
 
 [fmt]: https://github.com/rust-dev-tools/fmt-rfcs
+
 [`rustfmt`]:https://github.com/rust-lang/rustfmt
 
 ## Formatting C++ code
@@ -40,6 +41,26 @@ When modifying that code, use this command to format it:
 This uses a pinned version of `clang-format`, to avoid relying on the local
 environment.
 
+## Formatting and linting Python code
+
+The Rust repository contains quite a lof of Python code. We try to keep
+it both linted and formatted by the [ruff][ruff] tool.
+
+When modifying Python code, use this command to format it:
+```sh
+./x test tidy --extra-checks=py:fmt --bless
+```
+
+and the following command to run lints:
+```sh
+./x test tidy --extra-checks=py:lint
+```
+
+This uses a pinned version of `ruff`, to avoid relying on the local
+environment.
+
+[ruff]: https://github.com/astral-sh/ruff
+
 <a id="copyright"></a>
 
 <!-- REUSE-IgnoreStart -->
@@ -84,7 +105,7 @@ Using `_` in a match is convenient, but it means that when new
 variants are added to the enum, they may not get handled correctly.
 Ask yourself: if a new variant were added to this enum, what's the
 chance that it would want to use the `_` code, versus having some
-other treatment?  Unless the answer is "low", then prefer an
+other treatment? Unless the answer is "low", then prefer an
 exhaustive match. (The same advice applies to `if let` and `while
 let`, which are effectively tests for a single variant.)
 
@@ -124,7 +145,7 @@ See the [crates.io dependencies][crates] section.
 # How to structure your PR
 
 How you prepare the commits in your PR can make a big difference for the
-reviewer.  Here are some tips.
+reviewer. Here are some tips.
 
 **Isolate "pure refactorings" into their own commit.** For example, if
 you rename a method, then put that rename into its own commit, along
@@ -165,4 +186,5 @@ to the compiler.
   crate-related, often the spelling is changed to `krate`.
 
 [tcx]: ./ty.md
+
 [crates]: ./crates-io.md
diff --git a/src/rustc-driver/intro.md b/src/rustc-driver/intro.md
@@ -6,7 +6,7 @@ The [`rustc_driver`] is essentially `rustc`'s `main` function.
 It acts as the glue for running the various phases of the compiler in the correct order,
 using the interface defined in the [`rustc_interface`] crate. Where possible, using [`rustc_driver`] rather than [`rustc_interface`] is recommended.
 
-The main entry point of [`rustc_driver`] is [`rustc_driver::RunCompiler`][rd_rc].
+The main entry point of [`rustc_driver`] is [`rustc_driver::run_compiler`][rd_rc].
 This builder accepts the same command-line args as rustc as well as an implementation of [`Callbacks`][cb] and a couple of other optional options.
 [`Callbacks`][cb] is a `trait` that allows for custom compiler configuration,
 as well as allowing custom code to run after different phases of the compilation.
@@ -40,7 +40,7 @@ specifically [`rustc_driver_impl::run_compiler`][rdi_rc]
 [cb]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_driver/trait.Callbacks.html
 [example]: https://github.com/rust-lang/rustc-dev-guide/blob/master/examples/rustc-interface-example.rs
 [i_rc]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_interface/interface/fn.run_compiler.html
-[rd_rc]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_driver/struct.RunCompiler.html
+[rd_rc]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_driver/fn.run_compiler.html
 [rdi_rc]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_driver_impl/fn.run_compiler.html
 [stupid-stats]: https://github.com/nrc/stupid-stats
 [`nightly-rustc`]: https://doc.rust-lang.org/nightly/nightly-rustc/
diff --git a/src/stability.md b/src/stability.md
@@ -34,7 +34,8 @@ Previously, due to a [rustc bug], stable items inside unstable modules were
 available to stable code in that location.
 As of <!-- date-check --> September 2024, items with [accidentally stabilized
 paths] are marked with the `#[rustc_allowed_through_unstable_modules]` attribute
-to prevent code dependent on those paths from breaking.
+to prevent code dependent on those paths from breaking. Do *not* add this attribute
+to any more items unless that is needed to avoid breaking changes.
 
 The `unstable` attribute may also have the `soft` value, which makes it a
 future-incompatible deny-by-default lint instead of a hard error. This is used
diff --git a/src/tests/directives.md b/src/tests/directives.md
@@ -94,7 +94,7 @@ for more details.
 | Directive                         | Explanation                                                                                                              | Supported test suites                        | Possible values                                                                         |
 |-----------------------------------|--------------------------------------------------------------------------------------------------------------------------|----------------------------------------------|-----------------------------------------------------------------------------------------|
 | `check-run-results`               | Check run test binary `run-{pass,fail}` output snapshot                                                                  | `ui`, `crashes`, `incremental` if `run-pass` | N/A                                                                                     |
-| `error-pattern`                   | Check that output contains a specific string                                                                             | `ui`, `crashes`, `incremental` if `run-pass` | String                                                                                   |
+| `error-pattern`                   | Check that output contains a specific string                                                                             | `ui`, `crashes`, `incremental` if `run-pass` | String                                                                                  |
 | `regex-error-pattern`             | Check that output contains a regex pattern                                                                               | `ui`, `crashes`, `incremental` if `run-pass` | Regex                                                                                   |
 | `check-stdout`                    | Check `stdout` against `error-pattern`s from running test binary[^check_stdout]                                          | `ui`, `crashes`, `incremental`               | N/A                                                                                     |
 | `normalize-stderr-32bit`          | Normalize actual stderr (for 32-bit platforms) with a rule `"<raw>" -> "<normalized>"` before comparing against snapshot | `ui`, `incremental`                          | `"<RAW>" -> "<NORMALIZED>"`, `<RAW>`/`<NORMALIZED>` is regex capture and replace syntax |
@@ -152,6 +152,8 @@ Some examples of `X` in `ignore-X` or `only-X`:
   `compare-mode-split-dwarf`, `compare-mode-split-dwarf-single`
 - The two different test modes used by coverage tests:
   `ignore-coverage-map`, `ignore-coverage-run`
+- When testing a dist toolchain: `dist`
+  - This needs to be enabled with `COMPILETEST_ENABLE_DIST_TESTS=1`
 
 The following directives will check rustc build settings and target
 settings:
@@ -174,6 +176,7 @@ settings:
 - `needs-rust-lld` — ignores if the rust lld support is not enabled (`rust.lld =
   true` in `config.toml`)
 - `needs-threads` — ignores if the target does not have threading support
+- `needs-subprocess`  — ignores if the target does not have subprocess support
 - `needs-symlink` — ignores if the target does not support symlinks. This can be
   the case on Windows if the developer did not enable privileged symlink
   permissions.
