Merge from rustc

Author: The Miri Conjob Bot

src/bin/miri.rs

@@ -241,6 +241,7 @@ fn run_compiler(
     mut args: Vec<String>,
     target_crate: bool,
     callbacks: &mut (dyn rustc_driver::Callbacks + Send),
+    using_internal_features: std::sync::Arc<std::sync::atomic::AtomicBool>
 ) -> ! {
     if target_crate {
         // Miri needs a custom sysroot for target crates.
@@ -273,7 +274,8 @@ fn run_compiler(
 
     // Invoke compiler, and handle return code.
     let exit_code = rustc_driver::catch_with_exit_code(move || {
-        rustc_driver::RunCompiler::new(&args, callbacks).run()
+        rustc_driver::RunCompiler::new(&args, callbacks)
+            .set_using_internal_features(using_internal_features).run()
     });
     std::process::exit(exit_code)
 }
@@ -295,7 +297,7 @@ fn main() {
     // If the environment asks us to actually be rustc, then do that.
     if let Some(crate_kind) = env::var_os("MIRI_BE_RUSTC") {
         // Earliest rustc setup.
-        rustc_driver::install_ice_hook(rustc_driver::DEFAULT_BUG_REPORT_URL, |_| ());
+        let using_internal_features = rustc_driver::install_ice_hook(rustc_driver::DEFAULT_BUG_REPORT_URL, |_| ());
         rustc_driver::init_rustc_env_logger(&handler);
 
         let target_crate = if crate_kind == "target" {
@@ -311,11 +313,12 @@ fn main() {
             env::args().collect(),
             target_crate,
             &mut MiriBeRustCompilerCalls { target_crate },
+            using_internal_features,
         )
     }
 
     // Add an ICE bug report hook.
-    rustc_driver::install_ice_hook("https://github.com/rust-lang/miri/issues/new", |_| ());
+    let using_internal_features = rustc_driver::install_ice_hook("https://github.com/rust-lang/miri/issues/new", |_| ());
 
     // Init loggers the Miri way.
     init_early_loggers(&handler);
@@ -578,5 +581,5 @@ fn main() {
 
     debug!("rustc arguments: {:?}", rustc_args);
     debug!("crate arguments: {:?}", miri_config.args);
-    run_compiler(rustc_args, /* target_crate: */ true, &mut MiriCompilerCalls { miri_config })
+    run_compiler(rustc_args, /* target_crate: */ true, &mut MiriCompilerCalls { miri_config }, using_internal_features)
 }

tests/fail/dangling_pointers/dangling_pointer_deref_match_never.rs

@@ -0,0 +1,17 @@
+// Make sure we find these even with many checks disabled.
+//@compile-flags: -Zmiri-disable-alignment-check -Zmiri-disable-stacked-borrows -Zmiri-disable-validation
+
+#![allow(unreachable_code)]
+#![feature(never_type)]
+
+fn main() {
+    let p = {
+        let b = Box::new(42);
+        &*b as *const i32 as *const !
+    };
+    unsafe {
+        match *p {} //~ ERROR: entering unreachable code
+    }
+    panic!("this should never print");
+}
+

tests/fail/dangling_pointers/dangling_pointer_deref_match_never.stderr

@@ -0,0 +1,15 @@
+error: Undefined Behavior: entering unreachable code
+  --> $DIR/dangling_pointer_deref_match_never.rs:LL:CC
+   |
+LL |         match *p {}
+   |               ^^ entering unreachable code
+   |
+   = 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: BACKTRACE:
+   = note: inside `main` at $DIR/dangling_pointer_deref_match_never.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+

tests/fail/dangling_pointers/out_of_bounds_read.rs

@@ -1,5 +1,3 @@
-#![feature(pointer_byte_offsets)]
-
 fn main() {
     let v: Vec<u16> = vec![1, 2];
     // This read is also misaligned. We make sure that the OOB message has priority.

tests/fail/dangling_pointers/out_of_bounds_write.rs

@@ -1,5 +1,3 @@
-#![feature(pointer_byte_offsets)]
-
 fn main() {
     let mut v: Vec<u16> = vec![1, 2];
     // This read is also misaligned. We make sure that the OOB message has priority.

tests/fail/never_match_never.rs

@@ -0,0 +1,10 @@
+// This should fail even without validation
+//@compile-flags: -Zmiri-disable-validation
+
+#![feature(never_type)]
+#![allow(unreachable_code)]
+
+fn main() {
+    let ptr: *const (i32, !) = &0i32 as *const i32 as *const _;
+    unsafe { match (*ptr).1 {} } //~ ERROR: entering unreachable code
+}

tests/fail/never_match_never.stderr

@@ -0,0 +1,15 @@
+error: Undefined Behavior: entering unreachable code
+  --> $DIR/never_match_never.rs:LL:CC
+   |
+LL |     unsafe { match (*ptr).1 {} }
+   |                    ^^^^^^^^ entering unreachable code
+   |
+   = 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: BACKTRACE:
+   = note: inside `main` at $DIR/never_match_never.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+

tests/pass/dangling_pointer_deref_match_underscore.rs

@@ -0,0 +1,14 @@
+// A `_` binding in a match is a nop, so we do not detect that the pointer is dangling.
+//@compile-flags: -Zmiri-disable-alignment-check -Zmiri-disable-stacked-borrows -Zmiri-disable-validation
+
+fn main() {
+    let p = {
+        let b = Box::new(42);
+        &*b as *const i32
+    };
+    unsafe {
+        match *p {
+            _ => {}
+        }
+    }
+}

tests/pass/provenance.rs

@@ -1,7 +1,6 @@
 //@revisions: stack tree
 //@[tree]compile-flags: -Zmiri-tree-borrows
 #![feature(strict_provenance)]
-#![feature(pointer_byte_offsets)]
 use std::{mem, ptr};
 
 const PTR_SIZE: usize = mem::size_of::<&i32>();

tests/pass/union-uninhabited-match-underscore.rs

@@ -0,0 +1,17 @@
+fn main() {
+    #[derive(Copy, Clone)]
+    enum Void {}
+    union Uninit<T: Copy> {
+        value: T,
+        uninit: (),
+    }
+    unsafe {
+        let x: Uninit<Void> = Uninit { uninit: () };
+        match x.value {
+            // rustc warns about un unreachable pattern,
+            // but is wrong in unsafe code.
+            #[allow(unreachable_patterns)]
+            _ => println!("hi from the void!"),
+        }
+    }
+}