Fix

Author: saethlin

compiler/rustc_mir_transform/src/mono_checks/mod.rs

@@ -19,5 +19,12 @@ pub(super) fn check_mono_item<'tcx>(
 }
 
 pub(super) fn provide(providers: &mut Providers) {
-    *providers = Providers { skip_move_check_fns: move_check::skip_move_check_fns, ..*providers }
+    *providers = Providers {
+        skip_move_check_fns: move_check::skip_move_check_fns,
+        check_mono_item: |tcx, instance| {
+            let body = tcx.codegen_mir(instance);
+            check_mono_item(tcx, instance, body)
+        },
+        ..*providers
+    }
 }

compiler/rustc_monomorphize/messages.ftl

@@ -17,11 +17,4 @@ monomorphize_start_not_found = using `fn main` requires the standard library
 
 monomorphize_symbol_already_defined = symbol `{$symbol}` is already defined
 
-monomorphize_wasm_c_abi_transition =
-    this function {$is_call ->
-      [true] call
-      *[false] definition
-    } involves an argument of type `{$ty}` which is affected by the wasm ABI transition
-    .help = the "C" ABI Rust uses on wasm32-unknown-unknown will change to align with the standard "C" ABI for this target
-
 monomorphize_written_to_path = the full type name has been written to '{$path}'

compiler/rustc_monomorphize/src/collector.rs

@@ -220,14 +220,14 @@ use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
 use rustc_middle::mir::interpret::{AllocId, ErrorHandled, GlobalAlloc, Scalar};
 use rustc_middle::mir::mono::{CollectionMode, InstantiationMode, MonoItem};
 use rustc_middle::mir::visit::Visitor as MirVisitor;
-use rustc_middle::mir::{self, Location, MentionedItem};
+use rustc_middle::mir::{self, Location, MentionedItem, traversal};
 use rustc_middle::query::TyCtxtAt;
 use rustc_middle::ty::adjustment::{CustomCoerceUnsized, PointerCoercion};
 use rustc_middle::ty::layout::ValidityRequirement;
 use rustc_middle::ty::print::{shrunk_instance_name, with_no_trimmed_paths};
 use rustc_middle::ty::{
-    self, GenericArgs, GenericParamDefKind, Instance, InstanceKind, Ty, TyCtxt, TypeVisitableExt,
-    VtblEntry,
+    self, GenericArgs, GenericParamDefKind, Instance, InstanceKind, Ty, TyCtxt, TypeFoldable,
+    TypeVisitableExt, VtblEntry,
 };
 use rustc_middle::util::Providers;
 use rustc_middle::{bug, span_bug};
@@ -642,24 +642,38 @@ struct MirUsedCollector<'a, 'tcx> {
     /// See the comment in `collect_items_of_instance` for the purpose of this set.
     /// Note that this contains *not-monomorphized* items!
     used_mentioned_items: &'a mut UnordSet<MentionedItem<'tcx>>,
+    instance: Instance<'tcx>,
 }
 
 impl<'a, 'tcx> MirUsedCollector<'a, 'tcx> {
-    /// Evaluates a monomorphized constant.
+    fn monomorphize<T>(&self, value: T) -> T
+    where
+        T: TypeFoldable<TyCtxt<'tcx>>,
+    {
+        trace!("monomorphize: self.instance={:?}", self.instance);
+        self.instance.instantiate_mir_and_normalize_erasing_regions(
+            self.tcx,
+            ty::TypingEnv::fully_monomorphized(),
+            ty::EarlyBinder::bind(value),
+        )
+    }
+
+    /// Evaluates a *not yet monomorphized* constant.
     fn eval_constant(
         &mut self,
         constant: &mir::ConstOperand<'tcx>,
     ) -> Option<mir::ConstValue<'tcx>> {
+        let const_ = self.monomorphize(constant.const_);
         // Evaluate the constant. This makes const eval failure a collection-time error (rather than
         // a codegen-time error). rustc stops after collection if there was an error, so this
         // ensures codegen never has to worry about failing consts.
         // (codegen relies on this and ICEs will happen if this is violated.)
-        match constant.const_.eval(self.tcx, ty::TypingEnv::fully_monomorphized(), constant.span) {
+        match const_.eval(self.tcx, ty::TypingEnv::fully_monomorphized(), constant.span) {
             Ok(v) => Some(v),
             Err(ErrorHandled::TooGeneric(..)) => span_bug!(
                 constant.span,
                 "collection encountered polymorphic constant: {:?}",
-                constant.const_
+                const_
             ),
             Err(err @ ErrorHandled::Reported(..)) => {
                 err.emit_note(self.tcx);
@@ -689,6 +703,8 @@ impl<'a, 'tcx> MirVisitor<'tcx> for MirUsedCollector<'a, 'tcx> {
                 // *Before* monomorphizing, record that we already handled this mention.
                 self.used_mentioned_items
                     .insert(MentionedItem::UnsizeCast { source_ty, target_ty });
+                let target_ty = self.monomorphize(target_ty);
+                let source_ty = self.monomorphize(source_ty);
                 let (source_ty, target_ty) =
                     find_tails_for_unsizing(self.tcx.at(span), source_ty, target_ty);
                 // This could also be a different Unsize instruction, like
@@ -714,6 +730,7 @@ impl<'a, 'tcx> MirVisitor<'tcx> for MirUsedCollector<'a, 'tcx> {
                 let fn_ty = operand.ty(self.body, self.tcx);
                 // *Before* monomorphizing, record that we already handled this mention.
                 self.used_mentioned_items.insert(MentionedItem::Fn(fn_ty));
+                let fn_ty = self.monomorphize(fn_ty);
                 visit_fn_use(self.tcx, fn_ty, false, span, self.used_items);
             }
             mir::Rvalue::Cast(
@@ -724,6 +741,7 @@ impl<'a, 'tcx> MirVisitor<'tcx> for MirUsedCollector<'a, 'tcx> {
                 let source_ty = operand.ty(self.body, self.tcx);
                 // *Before* monomorphizing, record that we already handled this mention.
                 self.used_mentioned_items.insert(MentionedItem::Closure(source_ty));
+                let source_ty = self.monomorphize(source_ty);
                 if let ty::Closure(def_id, args) = *source_ty.kind() {
                     let instance =
                         Instance::resolve_closure(self.tcx, def_id, args, ty::ClosureKind::FnOnce);
@@ -775,12 +793,14 @@ impl<'a, 'tcx> MirVisitor<'tcx> for MirUsedCollector<'a, 'tcx> {
                 let callee_ty = func.ty(self.body, tcx);
                 // *Before* monomorphizing, record that we already handled this mention.
                 self.used_mentioned_items.insert(MentionedItem::Fn(callee_ty));
+                let callee_ty = self.monomorphize(callee_ty);
                 visit_fn_use(self.tcx, callee_ty, true, source, &mut self.used_items)
             }
             mir::TerminatorKind::Drop { ref place, .. } => {
                 let ty = place.ty(self.body, self.tcx).ty;
                 // *Before* monomorphizing, record that we already handled this mention.
                 self.used_mentioned_items.insert(MentionedItem::Drop(ty));
+                let ty = self.monomorphize(ty);
                 visit_drop_use(self.tcx, ty, true, source, self.used_items);
             }
             mir::TerminatorKind::InlineAsm { ref operands, .. } => {
@@ -790,6 +810,7 @@ impl<'a, 'tcx> MirVisitor<'tcx> for MirUsedCollector<'a, 'tcx> {
                             let fn_ty = value.const_.ty();
                             // *Before* monomorphizing, record that we already handled this mention.
                             self.used_mentioned_items.insert(MentionedItem::Fn(fn_ty));
+                            let fn_ty = self.monomorphize(fn_ty);
                             visit_fn_use(self.tcx, fn_ty, false, source, self.used_items);
                         }
                         mir::InlineAsmOperand::SymStatic { def_id } => {
@@ -1210,7 +1231,10 @@ fn collect_items_of_instance<'tcx>(
     instance: Instance<'tcx>,
     mode: CollectionMode,
 ) -> (MonoItems<'tcx>, MonoItems<'tcx>) {
-    let body = tcx.codegen_mir(instance);
+    // This item is getting monomorphized, do mono-time checks.
+    //tcx.ensure_ok().check_mono_item(instance);
+
+    let body = tcx.instance_mir(instance.def);
     // Naively, in "used" collection mode, all functions get added to *both* `used_items` and
     // `mentioned_items`. Mentioned items processing will then notice that they have already been
     // visited, but at that point each mentioned item has been monomorphized, added to the
@@ -1229,6 +1253,7 @@ fn collect_items_of_instance<'tcx>(
         body,
         used_items: &mut used_items,
         used_mentioned_items: &mut used_mentioned_items,
+        instance,
     };
 
     if mode == CollectionMode::UsedItems {
@@ -1237,7 +1262,7 @@ fn collect_items_of_instance<'tcx>(
                 collector.visit_var_debug_info(var_debug_info);
             }
         }
-        for (bb, data) in body.basic_blocks.iter_enumerated() {
+        for (bb, data) in traversal::reverse_postorder(body) {
             collector.visit_basic_block_data(bb, data)
         }
     }
@@ -1254,7 +1279,8 @@ fn collect_items_of_instance<'tcx>(
     // `used_items` above.
     for item in body.mentioned_items() {
         if !collector.used_mentioned_items.contains(&item.node) {
-            visit_mentioned_item(tcx, &item.node, item.span, &mut mentioned_items);
+            let item_mono = collector.monomorphize(item.node);
+            visit_mentioned_item(tcx, &item_mono, item.span, &mut mentioned_items);
         }
     }
 

tests/ui/abi/simd-abi-checks-avx.stderr

@@ -1,3 +1,35 @@
+error: this function definition uses SIMD vector type `Wrapper` which (with the chosen ABI) requires the `avx` target feature, which is not enabled
+  --> $DIR/simd-abi-checks-avx.rs:14:1
+   |
+LL | unsafe extern "C" fn w(_: Wrapper) {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ function defined here
+   |
+   = help: consider enabling it globally (`-C target-feature=+avx`) or locally (`#[target_feature(enable="avx")]`)
+
+error: this function definition uses SIMD vector type `std::arch::x86_64::__m256` which (with the chosen ABI) requires the `avx` target feature, which is not enabled
+  --> $DIR/simd-abi-checks-avx.rs:19:1
+   |
+LL | unsafe extern "C" fn f(_: __m256) {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ function defined here
+   |
+   = help: consider enabling it globally (`-C target-feature=+avx`) or locally (`#[target_feature(enable="avx")]`)
+
+error: this function definition uses SIMD vector type `std::arch::x86_64::__m256` which (with the chosen ABI) requires the `avx` target feature, which is not enabled
+  --> $DIR/simd-abi-checks-avx.rs:24:1
+   |
+LL | unsafe extern "C" fn g() -> __m256 {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ function defined here
+   |
+   = help: consider enabling it globally (`-C target-feature=+avx`) or locally (`#[target_feature(enable="avx")]`)
+
+error: this function call uses SIMD vector type `std::arch::x86_64::__m256` which (with the chosen ABI) requires the `avx` target feature, which is not enabled in the caller
+  --> $DIR/simd-abi-checks-avx.rs:53:8
+   |
+LL |     || g()
+   |        ^^^ function called here
+   |
+   = help: consider enabling it globally (`-C target-feature=+avx`) or locally (`#[target_feature(enable="avx")]`)
+
 error: this function call uses SIMD vector type `std::arch::x86_64::__m256` which (with the chosen ABI) requires the `avx` target feature, which is not enabled in the caller
   --> $DIR/simd-abi-checks-avx.rs:59:11
    |
@@ -54,43 +86,5 @@ LL |         some_extern();
    |
    = help: consider enabling it globally (`-C target-feature=+avx`) or locally (`#[target_feature(enable="avx")]`)
 
-error: this function definition uses SIMD vector type `std::arch::x86_64::__m256` which (with the chosen ABI) requires the `avx` target feature, which is not enabled
-  --> $DIR/simd-abi-checks-avx.rs:24:1
-   |
-LL | unsafe extern "C" fn g() -> __m256 {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ function defined here
-   |
-   = help: consider enabling it globally (`-C target-feature=+avx`) or locally (`#[target_feature(enable="avx")]`)
-
-error: this function definition uses SIMD vector type `std::arch::x86_64::__m256` which (with the chosen ABI) requires the `avx` target feature, which is not enabled
-  --> $DIR/simd-abi-checks-avx.rs:19:1
-   |
-LL | unsafe extern "C" fn f(_: __m256) {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ function defined here
-   |
-   = help: consider enabling it globally (`-C target-feature=+avx`) or locally (`#[target_feature(enable="avx")]`)
-
-error: this function definition uses SIMD vector type `Wrapper` which (with the chosen ABI) requires the `avx` target feature, which is not enabled
-  --> $DIR/simd-abi-checks-avx.rs:14:1
-   |
-LL | unsafe extern "C" fn w(_: Wrapper) {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ function defined here
-   |
-   = help: consider enabling it globally (`-C target-feature=+avx`) or locally (`#[target_feature(enable="avx")]`)
-
-error: this function call uses SIMD vector type `std::arch::x86_64::__m256` which (with the chosen ABI) requires the `avx` target feature, which is not enabled in the caller
-  --> $DIR/simd-abi-checks-avx.rs:53:8
-   |
-LL |     || g()
-   |        ^^^ function called here
-   |
-   = help: consider enabling it globally (`-C target-feature=+avx`) or locally (`#[target_feature(enable="avx")]`)
-
-note: the above error was encountered while instantiating `fn in_closure::{closure#0}`
-  --> $DIR/simd-abi-checks-avx.rs:81:9
-   |
-LL |         in_closure()();
-   |         ^^^^^^^^^^^^^^
-
 error: aborting due to 11 previous errors
 

tests/ui/abi/simd-abi-checks-s390x.z13_no_vector.stderr

@@ -1,3 +1,7 @@
+warning: unstable feature specified for `-Ctarget-feature`: `vector`
+   |
+   = note: this feature is not stably supported; its behavior can change in the future
+
 error: this function definition uses SIMD vector type `i8x8` which (with the chosen ABI) requires the `vector` target feature, which is not enabled
   --> $DIR/simd-abi-checks-s390x.rs:38:1
    |
@@ -82,5 +86,5 @@ LL | extern "C" fn vector_transparent_wrapper_arg(x: TransparentWrapper<i8x16>)
    |
    = help: consider enabling it globally (`-C target-feature=+vector`) or locally (`#[target_feature(enable="vector")]`)
 
-error: aborting due to 10 previous errors
+error: aborting due to 10 previous errors; 1 warning emitted
 

tests/ui/abi/simd-abi-checks-s390x.z13_soft_float.stderr

@@ -1,3 +1,12 @@
+warning: unstable feature specified for `-Ctarget-feature`: `vector`
+   |
+   = note: this feature is not stably supported; its behavior can change in the future
+
+warning: unknown and unstable feature specified for `-Ctarget-feature`: `soft-float`
+   |
+   = note: it is still passed through to the codegen backend, but use of this feature might be unsound and the behavior of this feature can change in the future
+   = help: consider filing a feature request
+
 error: this function definition uses SIMD vector type `i8x8` which (with the chosen ABI) requires the `vector` target feature, which is not enabled
   --> $DIR/simd-abi-checks-s390x.rs:38:1
    |
@@ -82,5 +91,5 @@ LL | extern "C" fn vector_transparent_wrapper_arg(x: TransparentWrapper<i8x16>)
    |
    = help: consider enabling it globally (`-C target-feature=+vector`) or locally (`#[target_feature(enable="vector")]`)
 
-error: aborting due to 10 previous errors
+error: aborting due to 10 previous errors; 2 warnings emitted
 

tests/ui/consts/mono-reachable-invalid-const.stderr

@@ -4,12 +4,6 @@ error[E0080]: evaluation of `Bar::<0>::ASSERT` failed
 LL |         ["oops"][b];
    |         ^^^^^^^^^^^ index out of bounds: the length is 1 but the index is 1
 
-note: erroneous constant encountered
-  --> $DIR/mono-reachable-invalid-const.rs:9:9
-   |
-LL |         ["oops"][b];
-   |         ^^^^^^^^^^^
-
 note: erroneous constant encountered
   --> $DIR/mono-reachable-invalid-const.rs:14:19
    |

tests/ui/inline-const/const-expr-generic-err.stderr

@@ -22,12 +22,6 @@ error[E0080]: evaluation of `bar::<0>::{constant#0}` failed
 LL |     const { N - 1 }
    |             ^^^^^ attempt to compute `0_usize - 1_usize`, which would overflow
 
-note: erroneous constant encountered
-  --> $DIR/const-expr-generic-err.rs:9:13
-   |
-LL |     const { N - 1 }
-   |             ^^^^^
-
 note: erroneous constant encountered
   --> $DIR/const-expr-generic-err.rs:9:5
    |

tests/ui/layout/post-mono-layout-cycle.rs

@@ -14,6 +14,7 @@ struct Wrapper<T: Trait> {
 }
 
 fn abi<T: Trait>(_: Option<Wrapper<T>>) {}
+//~^ ERROR: a cycle occurred during layout computation
 
 fn indirect<T: Trait>() {
     abi::<T>(None);

tests/ui/layout/post-mono-layout-cycle.stderr

@@ -5,12 +5,12 @@ error[E0391]: cycle detected when computing layout of `Wrapper<()>`
    = note: cycle used when computing layout of `core::option::Option<Wrapper<()>>`
    = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information
 
-note: the above error was encountered while instantiating `fn abi::<()>`
-  --> $DIR/post-mono-layout-cycle.rs:19:5
+error: a cycle occurred during layout computation
+  --> $DIR/post-mono-layout-cycle.rs:16:1
    |
-LL |     abi::<T>(None);
-   |     ^^^^^^^^^^^^^^
+LL | fn abi<T: Trait>(_: Option<Wrapper<T>>) {}
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-error: aborting due to 1 previous error
+error: aborting due to 2 previous errors
 
 For more information about this error, try `rustc --explain E0391`.

tests/ui/structs/default-field-values/post-mono.indirect.stderr

@@ -4,20 +4,6 @@ error[E0080]: evaluation of `Z::<1>::post_mono::{constant#0}` failed
 LL |     post_mono: usize = X / 0,
    |                        ^^^^^ attempt to divide `1_usize` by zero
 
-note: erroneous constant encountered
-  --> $DIR/post-mono.rs:7:24
-   |
-LL |     post_mono: usize = X / 0,
-   |                        ^^^^^
-
-note: erroneous constant encountered
-  --> $DIR/post-mono.rs:7:24
-   |
-LL |     post_mono: usize = X / 0,
-   |                        ^^^^^
-   |
-   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
-
 note: erroneous constant encountered
   --> $DIR/post-mono.rs:12:19
    |