Auto merge of rust-lang#121655 - matthiaskrgr:rollup-qpx3kks, r=matthiaskrgr

Rollup of 4 pull requests

Successful merges:

 - rust-lang#121598 (rename 'try' intrinsic to 'catch_unwind')
 - rust-lang#121639 (Update books)
 - rust-lang#121648 (Update Vec and String `{from,into}_raw_parts`-family docs)
 - rust-lang#121651 (Properly emit `expected ;` on `#[attr] expr`)

r? `@ghost`
`@rustbot` modify labels: rollup

Author: bors

compiler/rustc_codegen_cranelift/src/intrinsics/mod.rs

@@ -23,7 +23,7 @@ use rustc_middle::ty::layout::{HasParamEnv, ValidityRequirement};
 use rustc_middle::ty::print::{with_no_trimmed_paths, with_no_visible_paths};
 use rustc_middle::ty::GenericArgsRef;
 use rustc_span::source_map::Spanned;
-use rustc_span::symbol::{kw, sym, Symbol};
+use rustc_span::symbol::{sym, Symbol};
 
 pub(crate) use self::llvm::codegen_llvm_intrinsic_call;
 use crate::prelude::*;
@@ -1132,7 +1132,7 @@ fn codegen_regular_intrinsic_call<'tcx>(
             ret.write_cvalue(fx, val);
         }
 
-        kw::Try => {
+        sym::catch_unwind => {
             intrinsic_args!(fx, args => (f, data, catch_fn); intrinsic);
             let f = f.load_scalar(fx);
             let data = data.load_scalar(fx);

compiler/rustc_codegen_gcc/src/intrinsic/mod.rs

@@ -21,7 +21,7 @@ use rustc_middle::ty::{self, Instance, Ty};
 use rustc_middle::ty::layout::LayoutOf;
 #[cfg(feature="master")]
 use rustc_middle::ty::layout::{FnAbiOf, HasTyCtxt};
-use rustc_span::{Span, Symbol, symbol::kw, sym};
+use rustc_span::{Span, Symbol, sym};
 use rustc_target::abi::HasDataLayout;
 use rustc_target::abi::call::{ArgAbi, FnAbi, PassMode};
 use rustc_target::spec::PanicStrategy;
@@ -129,7 +129,7 @@ impl<'a, 'gcc, 'tcx> IntrinsicCallMethods<'tcx> for Builder<'a, 'gcc, 'tcx> {
                     let res = self.context.new_call(None, builtin, &[a]);
                     self.icmp(IntPredicate::IntEQ, res, self.const_i32(0))
                 }
-                kw::Try => {
+                sym::catch_unwind => {
                     try_intrinsic(
                         self,
                         args[0].immediate(),

compiler/rustc_codegen_llvm/src/intrinsic.rs

@@ -17,7 +17,7 @@ use rustc_hir as hir;
 use rustc_middle::ty::layout::{FnAbiOf, HasTyCtxt, LayoutOf};
 use rustc_middle::ty::{self, GenericArgsRef, Ty};
 use rustc_middle::{bug, span_bug};
-use rustc_span::{sym, symbol::kw, Span, Symbol};
+use rustc_span::{sym, Span, Symbol};
 use rustc_target::abi::{self, Align, HasDataLayout, Primitive};
 use rustc_target::spec::{HasTargetSpec, PanicStrategy};
 
@@ -133,8 +133,8 @@ impl<'ll, 'tcx> IntrinsicCallMethods<'tcx> for Builder<'_, 'll, 'tcx> {
             }
             sym::unlikely => self
                 .call_intrinsic("llvm.expect.i1", &[args[0].immediate(), self.const_bool(false)]),
-            kw::Try => {
-                try_intrinsic(
+            sym::catch_unwind => {
+                catch_unwind_intrinsic(
                     self,
                     args[0].immediate(),
                     args[1].immediate(),
@@ -457,7 +457,7 @@ impl<'ll, 'tcx> IntrinsicCallMethods<'tcx> for Builder<'_, 'll, 'tcx> {
     }
 }
 
-fn try_intrinsic<'ll>(
+fn catch_unwind_intrinsic<'ll>(
     bx: &mut Builder<'_, 'll, '_>,
     try_func: &'ll Value,
     data: &'ll Value,

compiler/rustc_hir_analysis/src/check/intrinsic.rs

@@ -12,7 +12,7 @@ use rustc_hir as hir;
 use rustc_middle::traits::{ObligationCause, ObligationCauseCode};
 use rustc_middle::ty::{self, Ty, TyCtxt};
 use rustc_span::def_id::LocalDefId;
-use rustc_span::symbol::{kw, sym};
+use rustc_span::symbol::sym;
 use rustc_span::{Span, Symbol};
 use rustc_target::spec::abi::Abi;
 
@@ -445,7 +445,7 @@ pub fn check_intrinsic_type(
                 )
             }
 
-            kw::Try => {
+            sym::catch_unwind => {
                 let mut_u8 = Ty::new_mut_ptr(tcx, tcx.types.u8);
                 let try_fn_ty = ty::Binder::dummy(tcx.mk_fn_sig(
                     [mut_u8],

compiler/rustc_parse/src/parser/diagnostics.rs

@@ -800,9 +800,8 @@ impl<'a> Parser<'a> {
                 {
                     Ok(next_attr) => next_attr,
                     Err(inner_err) => {
-                        err.cancel();
                         inner_err.cancel();
-                        return self.dcx().span_delayed_bug(expr.span, "not a tail expression");
+                        return err.emit();
                     }
                 }
                 && let ast::AttrKind::Normal(next_attr_kind) = next_attr.kind
@@ -813,9 +812,8 @@ impl<'a> Parser<'a> {
                 let next_expr = match snapshot.parse_expr() {
                     Ok(next_expr) => next_expr,
                     Err(inner_err) => {
-                        err.cancel();
                         inner_err.cancel();
-                        return self.dcx().span_delayed_bug(expr.span, "not a tail expression");
+                        return err.emit();
                     }
                 };
                 // We have for sure

compiler/rustc_span/src/symbol.rs

@@ -487,6 +487,7 @@ symbols! {
         call_once,
         caller_location,
         capture_disjoint_fields,
+        catch_unwind,
         cause,
         cdylib,
         ceilf32,

library/alloc/src/string.rs

@@ -864,7 +864,7 @@ impl String {
         }
     }
 
-    /// Decomposes a `String` into its raw components.
+    /// Decomposes a `String` into its raw components: `(pointer, length, capacity)`.
     ///
     /// Returns the raw pointer to the underlying data, the length of
     /// the string (in bytes), and the allocated capacity of the data
@@ -896,7 +896,7 @@ impl String {
         self.vec.into_raw_parts()
     }
 
-    /// Creates a new `String` from a length, capacity, and pointer.
+    /// Creates a new `String` from a pointer, a length and a capacity.
     ///
     /// # Safety
     ///

library/alloc/src/vec/mod.rs

@@ -481,7 +481,7 @@ impl<T> Vec<T> {
         Self::with_capacity_in(capacity, Global)
     }
 
-    /// Creates a `Vec<T>` directly from a pointer, a capacity, and a length.
+    /// Creates a `Vec<T>` directly from a pointer, a length, and a capacity.
     ///
     /// # Safety
     ///
@@ -672,7 +672,7 @@ impl<T, A: Allocator> Vec<T, A> {
         Vec { buf: RawVec::with_capacity_in(capacity, alloc), len: 0 }
     }
 
-    /// Creates a `Vec<T, A>` directly from a pointer, a capacity, a length,
+    /// Creates a `Vec<T, A>` directly from a pointer, a length, a capacity,
     /// and an allocator.
     ///
     /// # Safety
@@ -786,7 +786,7 @@ impl<T, A: Allocator> Vec<T, A> {
         unsafe { Vec { buf: RawVec::from_raw_parts_in(ptr, capacity, alloc), len: length } }
     }
 
-    /// Decomposes a `Vec<T>` into its raw components.
+    /// Decomposes a `Vec<T>` into its raw components: `(pointer, length, capacity)`.
     ///
     /// Returns the raw pointer to the underlying data, the length of
     /// the vector (in elements), and the allocated capacity of the
@@ -824,7 +824,7 @@ impl<T, A: Allocator> Vec<T, A> {
         (me.as_mut_ptr(), me.len(), me.capacity())
     }
 
-    /// Decomposes a `Vec<T>` into its raw components.
+    /// Decomposes a `Vec<T>` into its raw components: `(pointer, length, capacity, allocator)`.
     ///
     /// Returns the raw pointer to the underlying data, the length of the vector (in elements),
     /// the allocated capacity of the data (in elements), and the allocator. These are the same

library/core/src/intrinsics.rs

@@ -75,6 +75,9 @@ pub unsafe fn drop_in_place<T: ?Sized>(to_drop: *mut T) {
     unsafe { crate::ptr::drop_in_place(to_drop) }
 }
 
+#[cfg(bootstrap)]
+pub use self::r#try as catch_unwind;
+
 extern "rust-intrinsic" {
     // N.B., these intrinsics take raw pointers because they mutate aliased
     // memory, which is not valid for either `&` or `&mut`.
@@ -2382,16 +2385,24 @@ extern "rust-intrinsic" {
     #[rustc_nounwind]
     pub fn variant_count<T>() -> usize;
 
-    /// Rust's "try catch" construct which invokes the function pointer `try_fn`
-    /// with the data pointer `data`.
-    ///
-    /// The third argument is a function called if a panic occurs. This function
-    /// takes the data pointer and a pointer to the target-specific exception
-    /// object that was caught. For more information see the compiler's
-    /// source as well as std's catch implementation.
+    /// Rust's "try catch" construct for unwinding. Invokes the function pointer `try_fn` with the
+    /// data pointer `data`, and calls `catch_fn` if unwinding occurs while `try_fn` runs.
     ///
     /// `catch_fn` must not unwind.
+    ///
+    /// The third argument is a function called if an unwind occurs (both Rust unwinds and foreign
+    /// unwinds). This function takes the data pointer and a pointer to the target-specific
+    /// exception object that was caught. For more information, see the compiler's source as well as
+    /// std's `catch_unwind` implementation.
+    ///
+    /// The stable version of this intrinsic is `std::panic::catch_unwind`.
+    #[rustc_nounwind]
+    #[cfg(not(bootstrap))]
+    pub fn catch_unwind(try_fn: fn(*mut u8), data: *mut u8, catch_fn: fn(*mut u8, *mut u8)) -> i32;
+
+    /// For bootstrap only, see `catch_unwind`.
     #[rustc_nounwind]
+    #[cfg(bootstrap)]
     pub fn r#try(try_fn: fn(*mut u8), data: *mut u8, catch_fn: fn(*mut u8, *mut u8)) -> i32;
 
     /// Emits a `!nontemporal` store according to LLVM (see their docs).

library/panic_unwind/src/miri.rs

@@ -8,14 +8,14 @@ type Payload = Box<Box<dyn Any + Send>>;
 
 extern "Rust" {
     /// Miri-provided extern function to begin unwinding.
-    fn miri_start_panic(payload: *mut u8) -> !;
+    fn miri_start_unwind(payload: *mut u8) -> !;
 }
 
 pub unsafe fn panic(payload: Box<dyn Any + Send>) -> u32 {
-    // The payload we pass to `miri_start_panic` will be exactly the argument we get
+    // The payload we pass to `miri_start_unwind` will be exactly the argument we get
     // in `cleanup` below. So we just box it up once, to get something pointer-sized.
     let payload_box: Payload = Box::new(payload);
-    miri_start_panic(Box::into_raw(payload_box) as *mut u8)
+    miri_start_unwind(Box::into_raw(payload_box) as *mut u8)
 }
 
 pub unsafe fn cleanup(payload_box: *mut u8) -> Box<dyn Any + Send> {

library/std/src/panicking.rs

@@ -508,12 +508,12 @@ pub unsafe fn r#try<R, F: FnOnce() -> R>(f: F) -> Result<R, Box<dyn Any + Send>>
     // Access to the union's fields: this is `std` and we know that the `r#try`
     // intrinsic fills in the `r` or `p` union field based on its return value.
     //
-    // The call to `intrinsics::r#try` is made safe by:
+    // The call to `intrinsics::catch_unwind` is made safe by:
     // - `do_call`, the first argument, can be called with the initial `data_ptr`.
     // - `do_catch`, the second argument, can be called with the `data_ptr` as well.
     // See their safety preconditions for more information
     unsafe {
-        return if intrinsics::r#try(do_call::<F, R>, data_ptr, do_catch::<F, R>) == 0 {
+        return if intrinsics::catch_unwind(do_call::<F, R>, data_ptr, do_catch::<F, R>) == 0 {
             Ok(ManuallyDrop::into_inner(data.r))
         } else {
             Err(ManuallyDrop::into_inner(data.p))
@@ -540,7 +540,7 @@ pub unsafe fn r#try<R, F: FnOnce() -> R>(f: F) -> Result<R, Box<dyn Any + Send>>
     // Its must contains a valid `f` (type: F) value that can be use to fill
     // `data.r`.
     //
-    // This function cannot be marked as `unsafe` because `intrinsics::r#try`
+    // This function cannot be marked as `unsafe` because `intrinsics::catch_unwind`
     // expects normal function pointers.
     #[inline]
     fn do_call<F: FnOnce() -> R, R>(data: *mut u8) {
@@ -562,7 +562,7 @@ pub unsafe fn r#try<R, F: FnOnce() -> R>(f: F) -> Result<R, Box<dyn Any + Send>>
     // Since this uses `cleanup` it also hinges on a correct implementation of
     // `__rustc_panic_cleanup`.
     //
-    // This function cannot be marked as `unsafe` because `intrinsics::r#try`
+    // This function cannot be marked as `unsafe` because `intrinsics::catch_unwind`
     // expects normal function pointers.
     #[inline]
     #[rustc_nounwind] // `intrinsic::r#try` requires catch fn to be nounwind

src/doc/book

@@ -143,7 +143,7 @@ pub struct Thread<'mir, 'tcx> {
     join_status: ThreadJoinStatus,
 
     /// Stack of active panic payloads for the current thread. Used for storing
-    /// the argument of the call to `miri_start_panic` (the panic payload) when unwinding.
+    /// the argument of the call to `miri_start_unwind` (the panic payload) when unwinding.
     /// This is pointer-sized, and matches the `Payload` type in `src/libpanic_unwind/miri.rs`.
     ///
     /// In real unwinding, the payload gets passed as an argument to the landing pad,

src/doc/edition-guide

@@ -68,9 +68,9 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
         let ret = match ret {
             None =>
                 match link_name.as_str() {
-                    "miri_start_panic" => {
-                        // `check_shim` happens inside `handle_miri_start_panic`.
-                        this.handle_miri_start_panic(abi, link_name, args, unwind)?;
+                    "miri_start_unwind" => {
+                        // `check_shim` happens inside `handle_miri_start_unwind`.
+                        this.handle_miri_start_unwind(abi, link_name, args, unwind)?;
                         return Ok(None);
                     }
                     // This matches calls to the foreign item `panic_impl`.

src/doc/reference

@@ -54,7 +54,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
 
         // Some intrinsics are special and need the "ret".
         match intrinsic_name {
-            "try" => return this.handle_try(args, dest, ret),
+            "catch_unwind" => return this.handle_catch_unwind(args, dest, ret),
             _ => {}
         }
 

src/doc/rust-by-example

@@ -3,9 +3,9 @@
 //! The core pieces of the runtime are:
 //! - An implementation of `__rust_maybe_catch_panic` that pushes the invoked stack frame with
 //!   some extra metadata derived from the panic-catching arguments of `__rust_maybe_catch_panic`.
-//! - A hack in `libpanic_unwind` that calls the `miri_start_panic` intrinsic instead of the
+//! - A hack in `libpanic_unwind` that calls the `miri_start_unwind` intrinsic instead of the
 //!   target-native panic runtime. (This lives in the rustc repo.)
-//! - An implementation of `miri_start_panic` that stores its argument (the panic payload), and then
+//! - An implementation of `miri_start_unwind` that stores its argument (the panic payload), and then
 //!   immediately returns, but on the *unwind* edge (not the normal return edge), thus initiating unwinding.
 //! - A hook executed each time a frame is popped, such that if the frame pushed by `__rust_maybe_catch_panic`
 //!   gets popped *during unwinding*, we take the panic payload and store it according to the extra
@@ -44,9 +44,9 @@ impl VisitProvenance for CatchUnwindData<'_> {
 
 impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
 pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
-    /// Handles the special `miri_start_panic` intrinsic, which is called
+    /// Handles the special `miri_start_unwind` intrinsic, which is called
     /// by libpanic_unwind to delegate the actual unwinding process to Miri.
-    fn handle_miri_start_panic(
+    fn handle_miri_start_unwind(
         &mut self,
         abi: Abi,
         link_name: Symbol,
@@ -55,7 +55,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
     ) -> InterpResult<'tcx> {
         let this = self.eval_context_mut();
 
-        trace!("miri_start_panic: {:?}", this.frame().instance);
+        trace!("miri_start_unwind: {:?}", this.frame().instance);
 
         // Get the raw pointer stored in arg[0] (the panic payload).
         let [payload] = this.check_shim(abi, Abi::Rust, link_name, args)?;
@@ -69,7 +69,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
     }
 
     /// Handles the `try` intrinsic, the underlying implementation of `std::panicking::try`.
-    fn handle_try(
+    fn handle_catch_unwind(
         &mut self,
         args: &[OpTy<'tcx, Provenance>],
         dest: &PlaceTy<'tcx, Provenance>,
@@ -85,7 +85,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
         // what that is), and returns 1.
         // The `payload` is passed (by libstd) to `__rust_panic_cleanup`, which is then expected to
         // return a `Box<dyn Any + Send + 'static>`.
-        // In Miri, `miri_start_panic` is passed exactly that type, so we make the `payload` simply
+        // In Miri, `miri_start_unwind` is passed exactly that type, so we make the `payload` simply
         // a pointer to `Box<dyn Any + Send + 'static>`.
 
         // Get all the arguments.
@@ -141,7 +141,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
             // We set the return value of `try` to 1, since there was a panic.
             this.write_scalar(Scalar::from_i32(1), &catch_unwind.dest)?;
 
-            // The Thread's `panic_payload` holds what was passed to `miri_start_panic`.
+            // The Thread's `panic_payload` holds what was passed to `miri_start_unwind`.
             // This is exactly the second argument we need to pass to `catch_fn`.
             let payload = this.active_thread_mut().panic_payloads.pop().unwrap();
 

src/doc/rustc-dev-guide

@@ -8,7 +8,7 @@ fn main() {
     unsafe {
         // Make sure we check the ABI when Miri itself invokes a function
         // as part of a shim implementation.
-        std::intrinsics::r#try(
+        std::intrinsics::catch_unwind(
             //~^ ERROR: calling a function with ABI C using caller ABI Rust
             std::mem::transmute::<extern "C" fn(*mut u8), _>(try_fn),
             std::ptr::null_mut(),

src/tools/miri/src/concurrency/thread.rs

@@ -1,7 +1,7 @@
 error: Undefined Behavior: calling a function with ABI C using caller ABI Rust
   --> $DIR/check_callback_abi.rs:LL:CC
    |
-LL | /         std::intrinsics::r#try(
+LL | /         std::intrinsics::catch_unwind(
 LL | |
 LL | |             std::mem::transmute::<extern "C" fn(*mut u8), _>(try_fn),
 LL | |             std::ptr::null_mut(),

src/tools/miri/src/shims/foreign_items.rs

@@ -3,10 +3,10 @@
 #![feature(c_unwind)]
 
 extern "C" {
-    fn miri_start_panic(payload: *mut u8) -> !;
+    fn miri_start_unwind(payload: *mut u8) -> !;
 }
 
 fn main() {
-    unsafe { miri_start_panic(&mut 0) }
+    unsafe { miri_start_unwind(&mut 0) }
     //~^ ERROR: unwinding past a stack frame that does not allow unwinding
 }