Rollup merge of #147092 - cjgillot:late-validate-mir, r=compiler-errors

Do not compute optimized MIR if code does not type-check.

Since https://github.com/rust-lang/rust/pull/128612, we compute optimized MIR when `-Zvalidate-mir` is present.

This is done as part of required analyses, even if type-checking fails. This causes ICEs, as most of the mir-opt pipeline expects well-formed code.

Fixes rust-lang/rust#129095
Fixes rust-lang/rust#134174
Fixes rust-lang/rust#134654
Fixes rust-lang/rust#135570
Fixes rust-lang/rust#136381
Fixes rust-lang/rust#137468
Fixes rust-lang/rust#144491
Fixes rust-lang/rust#147011

This does not fix issue rust-lang/rust#137190, as it ICEs without `-Zvalidate-mir`.

r? ``@compiler-errors``

compiler/rustc_interface/src/passes.rs

@@ -1122,18 +1122,6 @@ fn run_required_analyses(tcx: TyCtxt<'_>) {
 
     sess.time("layout_testing", || layout_test::test_layout(tcx));
     sess.time("abi_testing", || abi_test::test_abi(tcx));
-
-    // If `-Zvalidate-mir` is set, we also want to compute the final MIR for each item
-    // (either its `mir_for_ctfe` or `optimized_mir`) since that helps uncover any bugs
-    // in MIR optimizations that may only be reachable through codegen, or other codepaths
-    // that requires the optimized/ctfe MIR, coroutine bodies, or evaluating consts.
-    if tcx.sess.opts.unstable_opts.validate_mir {
-        sess.time("ensuring_final_MIR_is_computable", || {
-            tcx.par_hir_body_owners(|def_id| {
-                tcx.instance_mir(ty::InstanceKind::Item(def_id.into()));
-            });
-        });
-    }
 }
 
 /// Runs the type-checking, region checking and other miscellaneous analysis
@@ -1199,6 +1187,20 @@ fn analysis(tcx: TyCtxt<'_>, (): ()) {
         // we will fail to emit overlap diagnostics. Thus we invoke it here unconditionally.
         let _ = tcx.all_diagnostic_items(());
     });
+
+    // If `-Zvalidate-mir` is set, we also want to compute the final MIR for each item
+    // (either its `mir_for_ctfe` or `optimized_mir`) since that helps uncover any bugs
+    // in MIR optimizations that may only be reachable through codegen, or other codepaths
+    // that requires the optimized/ctfe MIR, coroutine bodies, or evaluating consts.
+    // Nevertheless, wait after type checking is finished, as optimizing code that does not
+    // type-check is very prone to ICEs.
+    if tcx.sess.opts.unstable_opts.validate_mir {
+        sess.time("ensuring_final_MIR_is_computable", || {
+            tcx.par_hir_body_owners(|def_id| {
+                tcx.instance_mir(ty::InstanceKind::Item(def_id.into()));
+            });
+        });
+    }
 }
 
 /// Runs the codegen backend, after which the AST and analysis can

tests/crashes/129095.rs

@@ -1,13 +0,0 @@
-//@ known-bug: rust-lang/rust#129095
-//@ compile-flags: -Zmir-enable-passes=+GVN -Zmir-enable-passes=+Inline -Zvalidate-mir
-
-#![feature(adt_const_params, unsized_const_params)]
-#![allow(incomplete_features)]
-
-pub fn function_with_bytes<const BYTES: &'static [u8; 4]>() -> &'static [u8] {
-    BYTES
-}
-
-pub fn main() {
-    assert_eq!(function_with_bytes::<b"AAAAA">(), &[0x41, 0x41, 0x41, 0x41]);
-}

tests/crashes/134174.rs

@@ -1,17 +0,0 @@
-//@ known-bug: #134175
-//@compile-flags: -Zvalidate-mir -Zinline-mir=yes
-use std::vec::IntoIter;
-
-pub(crate) trait Foo: Iterator<Item = <Self as Foo>::Key> {
-    type Key;
-}
-
-impl Foo for IntoIter<i16> {}
-
-fn sum_foo<F: Foo<Key = i32>>(f: F) -> i32 {
-    f.fold(0, |a, b| a + b)
-}
-
-fn main() {
-    let x = sum_foo(vec![11, 10, 1].into_iter());
-}

tests/crashes/134654.rs

@@ -1,15 +0,0 @@
-//@ known-bug: #134654
-//@ compile-flags: -Zmir-enable-passes=+GVN -Zmir-enable-passes=+Inline -Zvalidate-mir
-//@ only-x86_64
-
-#![feature(adt_const_params, unsized_const_params)]
-#![allow(incomplete_features)]
-
-fn function_with_bytes<const BYTES:
-    &'static [u8; 0xa9008fb6c9d81e42_0e25730562a601c8_u128]>() -> &'static [u8] {
-    BYTES
-}
-
-fn main() {
-    function_with_bytes::<b"aa">() == &[];
-}

tests/crashes/135570.rs

@@ -1,15 +0,0 @@
-//@ known-bug: #135570
-//@compile-flags: -Zvalidate-mir -Zmir-enable-passes=+Inline -Copt-level=0 -Zmir-enable-passes=+GVN
-//@ only-x86_64
-
-#![feature(adt_const_params, unsized_const_params)]
-#![allow(incomplete_features)]
-
-fn function_with_bytes<const BYTES: &'static [u8; 0xc7b889180b67b07d_bc1a3c88783d35b5_u128]>(
-) -> &'static [u8] {
-    BYTES
-}
-
-fn main() {
-    function_with_bytes::<b"aa">() == &[];
-}

tests/crashes/136381.rs

@@ -1,18 +0,0 @@
-//@ known-bug: #136381
-//@ compile-flags: -Zvalidate-mir -Zmir-enable-passes=+GVN
-#![feature(trait_upcasting)]
-
-trait A {}
-trait B: A {
-    fn c(&self);
-}
-impl B for i32 {
-    fn c(self) {
-        todo!();
-    }
-}
-
-fn main() {
-    let baz: &dyn B = &1;
-    let bar: &dyn A = baz;
-}

tests/crashes/137190-1.rs

@@ -1,10 +0,0 @@
-//@ known-bug: #137190
-//@ compile-flags: -Zmir-opt-level=2 -Zvalidate-mir
-trait A {
-    fn b(&self);
-}
-trait C: A {}
-impl C for () {}
-fn main() {
-    (&() as &dyn C as &dyn A).b();
-}

tests/crashes/137468.rs

@@ -1,16 +0,0 @@
-//@ known-bug: #137468
-//@ compile-flags: -Copt-level=0 -Zmir-enable-passes=+GVN -Zvalidate-mir
-trait Supertrait<T> {}
-
-trait Identity {
-    type Selff;
-}
-
-trait Trait<P>: Supertrait<()> + Supertrait<<P as Identity>::Selff> {}
-
-impl<P> Trait<P> for () {}
-
-fn main() {
-    let x: &dyn Trait<()> = &();
-    let x: &dyn Supertrait<()> = x;
-}