Auto merge of rust-lang#106162 - Mark-Simulacrum:beta-next, r=Mark-Simulacrum

[beta] backport rollup

* Revert "Replace usage of ResumeTy in async lowering with Context" rust-lang#105915
*  Don't copy symbols from dylibs with -Zdylib-lto rust-lang#105800
*  rustdoc: Only hide lines starting with # in rust code blocks rust-lang#105539
*  Mangle "main" as "__main_void" on wasm32-wasi rust-lang#105468

r? `@ghost`

Author: bors

compiler/rustc_ast_lowering/src/expr.rs

@@ -16,7 +16,7 @@ use rustc_hir::def::Res;
 use rustc_hir::definitions::DefPathData;
 use rustc_session::errors::report_lit_error;
 use rustc_span::source_map::{respan, DesugaringKind, Span, Spanned};
-use rustc_span::symbol::{kw, sym, Ident};
+use rustc_span::symbol::{sym, Ident};
 use rustc_span::DUMMY_SP;
 use thin_vec::thin_vec;
 
@@ -585,38 +585,14 @@ impl<'hir> LoweringContext<'_, 'hir> {
     ) -> hir::ExprKind<'hir> {
         let output = ret_ty.unwrap_or_else(|| hir::FnRetTy::DefaultReturn(self.lower_span(span)));
 
-        // Resume argument type, which should be `&mut Context<'_>`.
-        // NOTE: Using the `'static` lifetime here is technically cheating.
-        // The `Future::poll` argument really is `&'a mut Context<'b>`, but we cannot
-        // express the fact that we are not storing it across yield-points yet,
-        // and we would thus run into lifetime errors.
-        // See <https://github.com/rust-lang/rust/issues/68923>.
-        // Our lowering makes sure we are not mis-using the `_task_context` input type
-        // in the sense that we are indeed not using it across yield points. We
-        // get a fresh `&mut Context` for each resume / call of `Future::poll`.
-        // This "cheating" was previously done with a `ResumeTy` that contained a raw
-        // pointer, and a `get_context` accessor that pulled the `Context` lifetimes
-        // out of thin air.
-        let context_lifetime_ident = Ident::with_dummy_span(kw::StaticLifetime);
-        let context_lifetime = self.arena.alloc(hir::Lifetime {
-            hir_id: self.next_id(),
-            ident: context_lifetime_ident,
-            res: hir::LifetimeName::Static,
-        });
-        let context_path =
-            hir::QPath::LangItem(hir::LangItem::Context, self.lower_span(span), None);
-        let context_ty = hir::MutTy {
-            ty: self.arena.alloc(hir::Ty {
-                hir_id: self.next_id(),
-                kind: hir::TyKind::Path(context_path),
-                span: self.lower_span(span),
-            }),
-            mutbl: hir::Mutability::Mut,
-        };
+        // Resume argument type: `ResumeTy`
+        let unstable_span =
+            self.mark_span_with_reason(DesugaringKind::Async, span, self.allow_gen_future.clone());
+        let resume_ty = hir::QPath::LangItem(hir::LangItem::ResumeTy, unstable_span, None);
         let input_ty = hir::Ty {
             hir_id: self.next_id(),
-            kind: hir::TyKind::Rptr(context_lifetime, context_ty),
-            span: self.lower_span(span),
+            kind: hir::TyKind::Path(resume_ty),
+            span: unstable_span,
         };
 
         // The closure/generator `FnDecl` takes a single (resume) argument of type `input_ty`.
@@ -674,9 +650,12 @@ impl<'hir> LoweringContext<'_, 'hir> {
             .map_or(false, |attrs| attrs.into_iter().any(|attr| attr.has_name(sym::track_caller)));
 
         let hir_id = self.lower_node_id(closure_node_id);
-        let unstable_span =
-            self.mark_span_with_reason(DesugaringKind::Async, span, self.allow_gen_future.clone());
         if track_caller {
+            let unstable_span = self.mark_span_with_reason(
+                DesugaringKind::Async,
+                span,
+                self.allow_gen_future.clone(),
+            );
             self.lower_attrs(
                 hir_id,
                 &[Attribute {
@@ -719,7 +698,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
     ///     mut __awaitee => loop {
     ///         match unsafe { ::std::future::Future::poll(
     ///             <::std::pin::Pin>::new_unchecked(&mut __awaitee),
-    ///             task_context,
+    ///             ::std::future::get_context(task_context),
     ///         ) } {
     ///             ::std::task::Poll::Ready(result) => break result,
     ///             ::std::task::Poll::Pending => {}
@@ -760,7 +739,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
         // unsafe {
         //     ::std::future::Future::poll(
         //         ::std::pin::Pin::new_unchecked(&mut __awaitee),
-        //         task_context,
+        //         ::std::future::get_context(task_context),
         //     )
         // }
         let poll_expr = {
@@ -778,10 +757,16 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 arena_vec![self; ref_mut_awaitee],
                 Some(expr_hir_id),
             );
+            let get_context = self.expr_call_lang_item_fn_mut(
+                gen_future_span,
+                hir::LangItem::GetContext,
+                arena_vec![self; task_context],
+                Some(expr_hir_id),
+            );
             let call = self.expr_call_lang_item_fn(
                 span,
                 hir::LangItem::FuturePoll,
-                arena_vec![self; new_unchecked, task_context],
+                arena_vec![self; new_unchecked, get_context],
                 Some(expr_hir_id),
             );
             self.arena.alloc(self.expr_unsafe(call))

compiler/rustc_codegen_ssa/src/back/link.rs

@@ -253,7 +253,7 @@ pub fn each_linked_rlib(
     };
     for &cnum in crates {
         match fmts.get(cnum.as_usize() - 1) {
-            Some(&Linkage::NotLinked | &Linkage::IncludedFromDylib) => continue,
+            Some(&Linkage::NotLinked | &Linkage::Dynamic | &Linkage::IncludedFromDylib) => continue,
             Some(_) => {}
             None => return Err(errors::LinkRlibError::MissingFormat),
         }

compiler/rustc_hir/src/lang_items.rs

@@ -286,9 +286,10 @@ language_item_table! {
 
     // FIXME(swatinem): the following lang items are used for async lowering and
     // should become obsolete eventually.
+    ResumeTy,                sym::ResumeTy,            resume_ty,                  Target::Struct,         GenericRequirement::None;
     IdentityFuture,          sym::identity_future,     identity_future_fn,         Target::Fn,             GenericRequirement::None;
+    GetContext,              sym::get_context,         get_context_fn,             Target::Fn,             GenericRequirement::None;
 
-    Context,                 sym::Context,             context,                    Target::Struct,         GenericRequirement::None;
     FuturePoll,              sym::poll,                future_poll_fn,             Target::Method(MethodKind::Trait { body: false }), GenericRequirement::None;
 
     FromFrom,                sym::from,                from_fn,                    Target::Method(MethodKind::Trait { body: false }), GenericRequirement::None;

compiler/rustc_span/src/symbol.rs

@@ -165,7 +165,6 @@ symbols! {
         Capture,
         Center,
         Clone,
-        Context,
         Continue,
         Copy,
         Count,
@@ -265,6 +264,7 @@ symbols! {
         Relaxed,
         Release,
         Result,
+        ResumeTy,
         Return,
         Right,
         Rust,
@@ -754,6 +754,7 @@ symbols! {
         generic_associated_types_extended,
         generic_const_exprs,
         generic_param_attrs,
+        get_context,
         global_allocator,
         global_asm,
         globs,

compiler/rustc_target/src/spec/wasm32_wasi.rs

@@ -104,6 +104,10 @@ pub fn target() -> Target {
     // `args::args()` makes the WASI API calls itself.
     options.main_needs_argc_argv = false;
 
+    // And, WASI mangles the name of "main" to distinguish between different
+    // signatures.
+    options.entry_name = "__main_void".into();
+
     Target {
         llvm_target: "wasm32-wasi".into(),
         pointer_width: 32,

library/core/src/future/mod.rs

@@ -44,7 +44,7 @@ pub use poll_fn::{poll_fn, PollFn};
 ///    non-Send/Sync as well, and we don't want that.
 ///
 /// It also simplifies the HIR lowering of `.await`.
-// FIXME(swatinem): This type can be removed when bumping the bootstrap compiler
+#[cfg_attr(not(bootstrap), lang = "ResumeTy")]
 #[doc(hidden)]
 #[unstable(feature = "gen_future", issue = "50547")]
 #[derive(Debug, Copy, Clone)]
@@ -61,7 +61,6 @@ unsafe impl Sync for ResumeTy {}
 /// This function returns a `GenFuture` underneath, but hides it in `impl Trait` to give
 /// better error messages (`impl Future` rather than `GenFuture<[closure.....]>`).
 // This is `const` to avoid extra errors after we recover from `const async fn`
-// FIXME(swatinem): This fn can be removed when bumping the bootstrap compiler
 #[cfg_attr(bootstrap, lang = "from_generator")]
 #[doc(hidden)]
 #[unstable(feature = "gen_future", issue = "50547")]
@@ -103,8 +102,7 @@ where
     GenFuture(gen)
 }
 
-// FIXME(swatinem): This fn can be removed when bumping the bootstrap compiler
-#[cfg_attr(bootstrap, lang = "get_context")]
+#[lang = "get_context"]
 #[doc(hidden)]
 #[unstable(feature = "gen_future", issue = "50547")]
 #[must_use]
@@ -115,10 +113,6 @@ pub unsafe fn get_context<'a, 'b>(cx: ResumeTy) -> &'a mut Context<'b> {
     unsafe { &mut *cx.0.as_ptr().cast() }
 }
 
-// FIXME(swatinem): This fn is currently needed to work around shortcomings
-// in type and lifetime inference.
-// See the comment at the bottom of `LoweringContext::make_async_expr` and
-// <https://github.com/rust-lang/rust/issues/104826>.
 #[cfg_attr(not(bootstrap), lang = "identity_future")]
 #[doc(hidden)]
 #[unstable(feature = "gen_future", issue = "50547")]

library/core/src/task/wake.rs

@@ -174,7 +174,6 @@ impl RawWakerVTable {
 /// Currently, `Context` only serves to provide access to a [`&Waker`](Waker)
 /// which can be used to wake the current task.
 #[stable(feature = "futures_api", since = "1.36.0")]
-#[cfg_attr(not(bootstrap), lang = "Context")]
 pub struct Context<'a> {
     waker: &'a Waker,
     // Ensure we future-proof against variance changes by forcing

src/librustdoc/html/markdown.rs

@@ -246,8 +246,6 @@ impl<'a, I: Iterator<Item = Event<'a>>> Iterator for CodeBlocks<'_, 'a, I> {
                 _ => {}
             }
         }
-        let lines = origtext.lines().filter_map(|l| map_line(l).for_html());
-        let text = lines.intersperse("\n".into()).collect::<String>();
 
         let parse_result = match kind {
             CodeBlockKind::Fenced(ref lang) => {
@@ -260,7 +258,7 @@ impl<'a, I: Iterator<Item = Event<'a>>> Iterator for CodeBlocks<'_, 'a, I> {
                                  <pre class=\"language-{}\"><code>{}</code></pre>\
                              </div>",
                             lang,
-                            Escape(&text),
+                            Escape(&origtext),
                         )
                         .into(),
                     ));
@@ -270,6 +268,9 @@ impl<'a, I: Iterator<Item = Event<'a>>> Iterator for CodeBlocks<'_, 'a, I> {
             CodeBlockKind::Indented => Default::default(),
         };
 
+        let lines = origtext.lines().filter_map(|l| map_line(l).for_html());
+        let text = lines.intersperse("\n".into()).collect::<String>();
+
         compile_fail = parse_result.compile_fail;
         should_panic = parse_result.should_panic;
         ignore = parse_result.ignore;

src/librustdoc/html/markdown/tests.rs

@@ -309,3 +309,40 @@ fn test_find_testable_code_line() {
     t("```rust\n```\n```rust\n```", &[1, 3]);
     t("```rust\n```\n ```rust\n```", &[1, 3]);
 }
+
+#[test]
+fn test_ascii_with_prepending_hashtag() {
+    fn t(input: &str, expect: &str) {
+        let mut map = IdMap::new();
+        let output = Markdown {
+            content: input,
+            links: &[],
+            ids: &mut map,
+            error_codes: ErrorCodes::Yes,
+            edition: DEFAULT_EDITION,
+            playground: &None,
+            heading_offset: HeadingOffset::H2,
+        }
+        .into_string();
+        assert_eq!(output, expect, "original: {}", input);
+    }
+
+    t(
+        r#"```ascii
+#..#.####.#....#.....##..
+#..#.#....#....#....#..#.
+####.###..#....#....#..#.
+#..#.#....#....#....#..#.
+#..#.#....#....#....#..#.
+#..#.####.####.####..##..
+```"#,
+        "<div class=\"example-wrap\"><pre class=\"language-ascii\"><code>\
+#..#.####.#....#.....##..
+#..#.#....#....#....#..#.
+####.###..#....#....#..#.
+#..#.#....#....#....#..#.
+#..#.#....#....#....#..#.
+#..#.####.####.####..##..
+</code></pre></div>",
+    );
+}

src/test/ui/async-await/async-await-let-else.drop-tracking.stderr

@@ -40,7 +40,7 @@ LL |   async fn bar2<T>(_: T) -> ! {
 LL | |     panic!()
 LL | | }
    | |_^
-   = note: required because it captures the following types: `&mut Context<'_>`, `Option<bool>`, `impl Future<Output = !>`, `()`
+   = note: required because it captures the following types: `ResumeTy`, `Option<bool>`, `impl Future<Output = !>`, `()`
 note: required because it's used within this `async fn` body
   --> $DIR/async-await-let-else.rs:21:32
    |

src/test/ui/async-await/issue-68112.drop_tracking.stderr

@@ -57,7 +57,7 @@ note: required because it appears within the type `impl Future<Output = Arc<RefC
    |
 LL | fn make_non_send_future2() -> impl Future<Output = Arc<RefCell<i32>>> {
    |                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   = note: required because it captures the following types: `&mut Context<'_>`, `impl Future<Output = Arc<RefCell<i32>>>`, `()`, `Ready<i32>`
+   = note: required because it captures the following types: `ResumeTy`, `impl Future<Output = Arc<RefCell<i32>>>`, `()`, `Ready<i32>`
 note: required because it's used within this `async` block
   --> $DIR/issue-68112.rs:60:20
    |

src/test/ui/async-await/issue-68112.no_drop_tracking.stderr

@@ -57,7 +57,7 @@ note: required because it appears within the type `impl Future<Output = Arc<RefC
    |
 LL | fn make_non_send_future2() -> impl Future<Output = Arc<RefCell<i32>>> {
    |                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   = note: required because it captures the following types: `&mut Context<'_>`, `impl Future<Output = Arc<RefCell<i32>>>`, `()`, `i32`, `Ready<i32>`
+   = note: required because it captures the following types: `ResumeTy`, `impl Future<Output = Arc<RefCell<i32>>>`, `()`, `i32`, `Ready<i32>`
 note: required because it's used within this `async` block
   --> $DIR/issue-68112.rs:60:20
    |

src/test/ui/async-await/issue-69446-fnmut-capture.stderr

@@ -14,9 +14,6 @@ LL | |     });
    |
    = note: `FnMut` closures only have access to their captured variables while they are executing...
    = note: ...therefore, they cannot allow references to captured variables to escape
-   = note: requirement occurs because of a mutable reference to `Context<'_>`
-   = note: mutable references are invariant over their type parameter
-   = help: see <https://doc.rust-lang.org/nomicon/subtyping.html> for more information about variance
 
 error: aborting due to previous error
 

src/test/ui/async-await/issue-70935-complex-spans.drop_tracking.stderr

@@ -18,7 +18,7 @@ LL |   async fn baz<T>(_c: impl FnMut() -> T) where T: Future<Output=()> {
    |  ___________________________________________________________________^
 LL | | }
    | |_^
-   = note: required because it captures the following types: `&mut Context<'_>`, `impl Future<Output = ()>`, `()`
+   = note: required because it captures the following types: `ResumeTy`, `impl Future<Output = ()>`, `()`
 note: required because it's used within this `async` block
   --> $DIR/issue-70935-complex-spans.rs:16:5
    |

src/test/ui/async-await/partial-drop-partial-reinit.drop_tracking.stderr

@@ -11,7 +11,7 @@ LL | async fn foo() {
    |
    = help: within `impl Future<Output = ()>`, the trait `Send` is not implemented for `NotSend`
    = note: required because it appears within the type `(NotSend,)`
-   = note: required because it captures the following types: `&mut Context<'_>`, `(NotSend,)`, `()`, `impl Future<Output = ()>`
+   = note: required because it captures the following types: `ResumeTy`, `(NotSend,)`, `()`, `impl Future<Output = ()>`
 note: required because it's used within this `async fn` body
   --> $DIR/partial-drop-partial-reinit.rs:31:16
    |

src/test/ui/async-await/partial-drop-partial-reinit.no_drop_tracking.stderr

@@ -11,7 +11,7 @@ LL | async fn foo() {
    |
    = help: within `impl Future<Output = ()>`, the trait `Send` is not implemented for `NotSend`
    = note: required because it appears within the type `(NotSend,)`
-   = note: required because it captures the following types: `&mut Context<'_>`, `(NotSend,)`, `impl Future<Output = ()>`, `()`
+   = note: required because it captures the following types: `ResumeTy`, `(NotSend,)`, `impl Future<Output = ()>`, `()`
 note: required because it's used within this `async fn` body
   --> $DIR/partial-drop-partial-reinit.rs:31:16
    |

src/test/ui/lto/auxiliary/thinlto-dylib.rs

@@ -0,0 +1,23 @@
+// Auxiliary crate for test issue-105637: the LTOed dylib which had duplicate symbols from libstd,
+// breaking the panic hook feature.
+//
+// This simulates the `rustc_driver` crate, and the main crate simulates rustc's main binary hooking
+// into this driver.
+
+// compile-flags: -Zdylib-lto -C lto=thin
+
+use std::panic;
+
+pub fn main() {
+    // Install the hook we want to see executed
+    panic::set_hook(Box::new(|_| {
+        eprintln!("LTOed auxiliary crate panic hook");
+    }));
+
+    // Trigger the panic hook with an ICE
+    run_compiler();
+}
+
+fn run_compiler() {
+    panic!("ICEing");
+}

src/test/ui/lto/issue-105637.rs

@@ -0,0 +1,28 @@
+// Regression test for issue #105637: `-Zdylib-lto` with LTO duplicated symbols from other dylibs,
+// in this case from libstd.
+//
+// That manifested as both `rustc_driver` and rustc's "main" (`compiler/rustc`) having their own
+// `std::panicking::HOOK` static, and the hook in rustc's main (the default stdlib's) being executed
+// when rustc ICEs, instead of the overriden hook from `rustc_driver` (which also displays the query
+// stack and information on how to open a GH issue for the encountered ICE).
+//
+// In this test, we reproduce this setup by installing a panic hook in both the main and an LTOed
+// dylib: the last hook set should be the one being executed, the dylib's.
+
+// aux-build: thinlto-dylib.rs
+// run-fail
+// check-run-results
+
+extern crate thinlto_dylib;
+
+use std::panic;
+
+fn main() {
+    // We don't want to see this panic hook executed
+    std::panic::set_hook(Box::new(|_| {
+        eprintln!("main crate panic hook");
+    }));
+
+    // Have the LTOed dylib install its own hook and panic, we want to see its hook executed.
+    thinlto_dylib::main();
+}

src/test/ui/lto/issue-105637.run.stderr

@@ -0,0 +1 @@
+LTOed auxiliary crate panic hook