Auto merge of #152701 - jhpratt:rollup-clRaY9x, r=jhpratt

Rollup of 6 pull requests

Successful merges:

 - rust-lang/rust#148206 (Deduplicated float tests and unified in floats/mod.rs)
 - rust-lang/rust#150601 (support c-variadic functions in `rustc_const_eval`)
 - rust-lang/rust#152103 (Consider captures to be used by closures that unwind)
 - rust-lang/rust#152296 (Port `rust_nonnull_optimization_guaranteed` and `rustc_do_not_const_check` to the new attribute parser)
 - rust-lang/rust#152648 (Remove timing assertion from `oneshot::send_before_recv_timeout`)
 - rust-lang/rust#152686 (bootstrap: Inline the `is_tool` check for setting `-Zforce-unstable-if-unmarked`)

Failed merges:

 - rust-lang/rust#152512 (core: Implement feature `float_exact_integer_constants`)

Author: bors

src/alloc_addresses/mod.rs

@@ -184,7 +184,7 @@ trait EvalContextExtPriv<'tcx>: crate::MiriInterpCxExt<'tcx> {
                 }
                 #[cfg(not(all(unix, feature = "native-lib")))]
                 AllocKind::Function => dummy_alloc(params),
-                AllocKind::VTable => dummy_alloc(params),
+                AllocKind::VTable | AllocKind::VaList => dummy_alloc(params),
                 AllocKind::TypeId | AllocKind::Dead => unreachable!(),
             };
             // We don't have to expose this pointer yet, we do that in `prepare_for_native_call`.

src/borrow_tracker/stacked_borrows/mod.rs

@@ -655,7 +655,7 @@ trait EvalContextPrivExt<'tcx, 'ecx>: crate::MiriInterpCxExt<'tcx> {
                         dcx.log_protector();
                     }
                 },
-                AllocKind::Function | AllocKind::VTable | AllocKind::TypeId | AllocKind::Dead => {
+                AllocKind::Function | AllocKind::VTable | AllocKind::TypeId | AllocKind::Dead | AllocKind::VaList => {
                     // No stacked borrows on these allocations.
                 }
             }
@@ -1014,7 +1014,11 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
                 trace!("Stacked Borrows tag {tag:?} exposed in {alloc_id:?}");
                 alloc_extra.borrow_tracker_sb().borrow_mut().exposed_tags.insert(tag);
             }
-            AllocKind::Function | AllocKind::VTable | AllocKind::TypeId | AllocKind::Dead => {
+            AllocKind::Function
+            | AllocKind::VTable
+            | AllocKind::TypeId
+            | AllocKind::Dead
+            | AllocKind::VaList => {
                 // No stacked borrows on these allocations.
             }
         }

src/borrow_tracker/tree_borrows/mod.rs

@@ -577,7 +577,11 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
                 let protected = protected_tags.contains_key(&tag);
                 alloc_extra.borrow_tracker_tb().borrow_mut().expose_tag(tag, protected);
             }
-            AllocKind::Function | AllocKind::VTable | AllocKind::TypeId | AllocKind::Dead => {
+            AllocKind::Function
+            | AllocKind::VTable
+            | AllocKind::TypeId
+            | AllocKind::Dead
+            | AllocKind::VaList => {
                 // No tree borrows on these allocations.
             }
         }

tests/fail/c-variadic-mismatch-count.rs

@@ -0,0 +1,13 @@
+#![feature(c_variadic)]
+
+unsafe extern "C" fn helper(_: i32, _: ...) {}
+
+fn main() {
+    unsafe {
+        let f = helper as *const ();
+        let f = std::mem::transmute::<_, unsafe extern "C" fn(...)>(f);
+
+        f(1);
+        //~^ ERROR: Undefined Behavior
+    }
+}

tests/fail/c-variadic-mismatch-count.stderr

@@ -0,0 +1,13 @@
+error: Undefined Behavior: calling a C-variadic function with 0 fixed arguments, but the function expects 1
+  --> tests/fail/c-variadic-mismatch-count.rs:LL:CC
+   |
+LL |         f(1);
+   |         ^^^^ Undefined Behavior occurred here
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to 1 previous error
+

tests/fail/c-variadic-mismatch.rs

@@ -0,0 +1,13 @@
+#![feature(c_variadic)]
+
+unsafe extern "C" fn helper(_: i32, _: ...) {}
+
+fn main() {
+    unsafe {
+        let f = helper as *const ();
+        let f = std::mem::transmute::<_, unsafe extern "C" fn(_: i32, _: i64)>(f);
+
+        f(1i32, 1i64);
+        //~^ ERROR: Undefined Behavior: calling a function where the caller and callee disagree on whether the function is C-variadic
+    }
+}

tests/fail/c-variadic-mismatch.stderr

@@ -0,0 +1,13 @@
+error: Undefined Behavior: calling a function where the caller and callee disagree on whether the function is C-variadic
+  --> tests/fail/c-variadic-mismatch.rs:LL:CC
+   |
+LL |         f(1i32, 1i64);
+   |         ^^^^^^^^^^^^^ Undefined Behavior occurred here
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to 1 previous error
+

tests/fail/c-variadic.rs

@@ -0,0 +1,15 @@
+#![feature(c_variadic)]
+
+//@error-in-other-file: Undefined Behavior: more C-variadic arguments read than were passed
+
+fn read_too_many() {
+    unsafe extern "C" fn variadic(mut ap: ...) {
+        ap.arg::<i32>();
+    }
+
+    unsafe { variadic() };
+}
+
+fn main() {
+    read_too_many();
+}

tests/fail/c-variadic.stderr

@@ -0,0 +1,22 @@
+error: Undefined Behavior: more C-variadic arguments read than were passed
+  --> RUSTLIB/core/src/ffi/va_list.rs:LL:CC
+   |
+LL |         unsafe { va_arg(self) }
+   |                  ^^^^^^^^^^^^ Undefined Behavior occurred here
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: stack backtrace:
+           0: std::ffi::VaList::<'_>::arg
+               at RUSTLIB/core/src/ffi/va_list.rs:LL:CC
+           1: read_too_many::variadic
+               at tests/fail/c-variadic.rs:LL:CC
+           2: read_too_many
+               at tests/fail/c-variadic.rs:LL:CC
+           3: main
+               at tests/fail/c-variadic.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to 1 previous error
+

tests/pass/c-variadic.rs

@@ -0,0 +1,115 @@
+#![feature(c_variadic)]
+
+use std::ffi::{CStr, VaList, c_char, c_double, c_int, c_long};
+
+fn ignores_arguments() {
+    unsafe extern "C" fn variadic(_: ...) {}
+
+    unsafe { variadic() };
+    unsafe { variadic(1, 2, 3) };
+}
+
+fn echo() {
+    unsafe extern "C" fn variadic(mut ap: ...) -> i32 {
+        ap.arg()
+    }
+
+    assert_eq!(unsafe { variadic(1) }, 1);
+    assert_eq!(unsafe { variadic(3, 2, 1) }, 3);
+}
+
+fn forward_by_val() {
+    unsafe fn helper(mut ap: VaList) -> i32 {
+        ap.arg()
+    }
+
+    unsafe extern "C" fn variadic(ap: ...) -> i32 {
+        helper(ap)
+    }
+
+    assert_eq!(unsafe { variadic(1) }, 1);
+    assert_eq!(unsafe { variadic(3, 2, 1) }, 3);
+}
+
+fn forward_by_ref() {
+    unsafe fn helper(ap: &mut VaList) -> i32 {
+        ap.arg()
+    }
+
+    unsafe extern "C" fn variadic(mut ap: ...) -> i32 {
+        helper(&mut ap)
+    }
+
+    assert_eq!(unsafe { variadic(1) }, 1);
+    assert_eq!(unsafe { variadic(3, 2, 1) }, 3);
+}
+
+#[allow(improper_ctypes_definitions)]
+fn nested() {
+    unsafe fn helper(mut ap1: VaList, mut ap2: VaList) -> (i32, i32) {
+        (ap1.arg(), ap2.arg())
+    }
+
+    unsafe extern "C" fn variadic2(ap1: VaList, ap2: ...) -> (i32, i32) {
+        helper(ap1, ap2)
+    }
+
+    unsafe extern "C" fn variadic1(ap1: ...) -> (i32, i32) {
+        variadic2(ap1, 2, 2)
+    }
+
+    assert_eq!(unsafe { variadic1(1) }, (1, 2));
+
+    let (a, b) = unsafe { variadic1(1, 1) };
+
+    assert_eq!(a, 1);
+    assert_eq!(b, 2);
+}
+
+fn various_types() {
+    unsafe extern "C" fn check_list_2(mut ap: ...) {
+        macro_rules! continue_if {
+            ($cond:expr) => {
+                if !($cond) {
+                    panic!();
+                }
+            };
+        }
+
+        unsafe fn compare_c_str(ptr: *const c_char, val: &str) -> bool {
+            match CStr::from_ptr(ptr).to_str() {
+                Ok(cstr) => cstr == val,
+                Err(_) => panic!(),
+            }
+        }
+
+        continue_if!(ap.arg::<c_double>().floor() == 3.14f64.floor());
+        continue_if!(ap.arg::<c_long>() == 12);
+        continue_if!(ap.arg::<c_int>() == 'a' as c_int);
+        continue_if!(ap.arg::<c_double>().floor() == 6.18f64.floor());
+        continue_if!(compare_c_str(ap.arg::<*const c_char>(), "Hello"));
+        continue_if!(ap.arg::<c_int>() == 42);
+        continue_if!(compare_c_str(ap.arg::<*const c_char>(), "World"));
+    }
+
+    unsafe {
+        check_list_2(
+            3.14 as c_double,
+            12 as c_long,
+            b'a' as c_int,
+            6.28 as c_double,
+            c"Hello".as_ptr(),
+            42 as c_int,
+            c"World".as_ptr(),
+        );
+    }
+}
+
+fn main() {
+    ignores_arguments();
+    echo();
+    forward_by_val();
+    forward_by_ref();
+    nested();
+    various_types();
+}