about summary refs log tree commit diff
path: root/compiler
diff options
context:
space:
mode:
Diffstat (limited to 'compiler')
-rw-r--r--compiler/rustc_const_eval/src/interpret/terminator.rs9
-rw-r--r--compiler/rustc_const_eval/src/transform/validate.rs11
-rw-r--r--compiler/rustc_middle/src/mir/mod.rs8
-rw-r--r--compiler/rustc_mir_transform/src/deref_separator.rs110
-rw-r--r--compiler/rustc_mir_transform/src/generator.rs4
-rw-r--r--compiler/rustc_mir_transform/src/inline.rs3
-rw-r--r--compiler/rustc_parse/src/parser/item.rs41
-rw-r--r--compiler/rustc_typeck/src/check/check.rs13
8 files changed, 109 insertions, 90 deletions
diff --git a/compiler/rustc_const_eval/src/interpret/terminator.rs b/compiler/rustc_const_eval/src/interpret/terminator.rs
index a5c7d4c8e20..10da2f803af 100644
--- a/compiler/rustc_const_eval/src/interpret/terminator.rs
+++ b/compiler/rustc_const_eval/src/interpret/terminator.rs
@@ -185,7 +185,14 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 // No question
                 return true;
             }
-            // Compare layout
+            if caller_abi.layout.size != callee_abi.layout.size
+                || caller_abi.layout.align.abi != callee_abi.layout.align.abi
+            {
+                // This cannot go well...
+                // FIXME: What about unsized types?
+                return false;
+            }
+            // The rest *should* be okay, but we are extra conservative.
             match (caller_abi.layout.abi, callee_abi.layout.abi) {
                 // Different valid ranges are okay (once we enforce validity,
                 // that will take care to make it UB to leave the range, just
diff --git a/compiler/rustc_const_eval/src/transform/validate.rs b/compiler/rustc_const_eval/src/transform/validate.rs
index 54c2daf9ac2..665b07c9f89 100644
--- a/compiler/rustc_const_eval/src/transform/validate.rs
+++ b/compiler/rustc_const_eval/src/transform/validate.rs
@@ -4,6 +4,7 @@ use rustc_data_structures::fx::FxHashSet;
 use rustc_index::bit_set::BitSet;
 use rustc_infer::infer::TyCtxtInferExt;
 use rustc_middle::mir::interpret::Scalar;
+use rustc_middle::mir::visit::NonUseContext::VarDebugInfo;
 use rustc_middle::mir::visit::{PlaceContext, Visitor};
 use rustc_middle::mir::{
     traversal, AggregateKind, BasicBlock, BinOp, Body, BorrowKind, Local, Location, MirPass,
@@ -302,9 +303,17 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
         self.super_projection_elem(local, proj_base, elem, context, location);
     }
 
-    fn visit_place(&mut self, place: &Place<'tcx>, _: PlaceContext, _: Location) {
+    fn visit_place(&mut self, place: &Place<'tcx>, cntxt: PlaceContext, location: Location) {
         // Set off any `bug!`s in the type computation code
         let _ = place.ty(&self.body.local_decls, self.tcx);
+
+        if self.mir_phase >= MirPhase::Derefered
+            && place.projection.len() > 1
+            && cntxt != PlaceContext::NonUse(VarDebugInfo)
+            && place.projection[1..].contains(&ProjectionElem::Deref)
+        {
+            self.fail(location, format!("{:?}, has deref at the wrong place", place));
+        }
     }
 
     fn visit_rvalue(&mut self, rvalue: &Rvalue<'tcx>, location: Location) {
diff --git a/compiler/rustc_middle/src/mir/mod.rs b/compiler/rustc_middle/src/mir/mod.rs
index 71cea005cf8..b09d39996f4 100644
--- a/compiler/rustc_middle/src/mir/mod.rs
+++ b/compiler/rustc_middle/src/mir/mod.rs
@@ -172,12 +172,14 @@ pub enum MirPhase {
     /// terminator means that the auto-generated drop glue will be invoked. Also, `Copy` operands
     /// are allowed for non-`Copy` types.
     DropsLowered = 3,
+    /// After this projections may only contain deref projections as the first element.
+    Derefered = 4,
     /// Beginning with this phase, the following variant is disallowed:
     /// * [`Rvalue::Aggregate`] for any `AggregateKind` except `Array`
     ///
     /// And the following variant is allowed:
     /// * [`StatementKind::SetDiscriminant`]
-    Deaggregated = 4,
+    Deaggregated = 5,
     /// Before this phase, generators are in the "source code" form, featuring `yield` statements
     /// and such. With this phase change, they are transformed into a proper state machine. Running
     /// optimizations before this change can be potentially dangerous because the source code is to
@@ -191,8 +193,8 @@ pub enum MirPhase {
     /// Beginning with this phase, the following variants are disallowed:
     /// * [`TerminatorKind::Yield`](terminator::TerminatorKind::Yield)
     /// * [`TerminatorKind::GeneratorDrop`](terminator::TerminatorKind::GeneratorDrop)
-    GeneratorsLowered = 5,
-    Optimized = 6,
+    GeneratorsLowered = 6,
+    Optimized = 7,
 }
 
 impl MirPhase {
diff --git a/compiler/rustc_mir_transform/src/deref_separator.rs b/compiler/rustc_mir_transform/src/deref_separator.rs
index 57a95a67df7..bfb3ad1be27 100644
--- a/compiler/rustc_mir_transform/src/deref_separator.rs
+++ b/compiler/rustc_mir_transform/src/deref_separator.rs
@@ -1,9 +1,11 @@
 use crate::MirPass;
 use rustc_index::vec::IndexVec;
 use rustc_middle::mir::patch::MirPatch;
+use rustc_middle::mir::visit::NonUseContext::VarDebugInfo;
 use rustc_middle::mir::visit::{MutVisitor, PlaceContext};
 use rustc_middle::mir::*;
 use rustc_middle::ty::TyCtxt;
+
 pub struct Derefer;
 
 pub struct DerefChecker<'tcx> {
@@ -17,63 +19,68 @@ impl<'tcx> MutVisitor<'tcx> for DerefChecker<'tcx> {
         self.tcx
     }
 
-    fn visit_place(&mut self, place: &mut Place<'tcx>, _: PlaceContext, loc: Location) {
-        let mut place_local = place.local;
-        let mut last_len = 0;
-        let mut last_deref_idx = 0;
+    fn visit_place(&mut self, place: &mut Place<'tcx>, cntxt: PlaceContext, loc: Location) {
+        if !place.projection.is_empty()
+            && cntxt != PlaceContext::NonUse(VarDebugInfo)
+            && place.projection[1..].contains(&ProjectionElem::Deref)
+        {
+            let mut place_local = place.local;
+            let mut last_len = 0;
+            let mut last_deref_idx = 0;
 
-        let mut prev_temp: Option<Local> = None;
+            let mut prev_temp: Option<Local> = None;
 
-        for (idx, (p_ref, p_elem)) in place.iter_projections().enumerate() {
-            if p_elem == ProjectionElem::Deref && !p_ref.projection.is_empty() {
-                last_deref_idx = idx;
-            }
-        }
-
-        for (idx, (p_ref, p_elem)) in place.iter_projections().enumerate() {
-            if p_elem == ProjectionElem::Deref && !p_ref.projection.is_empty() {
-                let ty = p_ref.ty(&self.local_decls, self.tcx).ty;
-                let temp = self.patcher.new_local_with_info(
-                    ty,
-                    self.local_decls[p_ref.local].source_info.span,
-                    Some(Box::new(LocalInfo::DerefTemp)),
-                );
-
-                self.patcher.add_statement(loc, StatementKind::StorageLive(temp));
-
-                // We are adding current p_ref's projections to our
-                // temp value, excluding projections we already covered.
-                let deref_place = Place::from(place_local)
-                    .project_deeper(&p_ref.projection[last_len..], self.tcx);
-
-                self.patcher.add_assign(
-                    loc,
-                    Place::from(temp),
-                    Rvalue::Use(Operand::Move(deref_place)),
-                );
-                place_local = temp;
-                last_len = p_ref.projection.len();
-
-                // Change `Place` only if we are actually at the Place's last deref
-                if idx == last_deref_idx {
-                    let temp_place =
-                        Place::from(temp).project_deeper(&place.projection[idx..], self.tcx);
-                    *place = temp_place;
+            for (idx, elem) in place.projection[0..].iter().enumerate() {
+                if *elem == ProjectionElem::Deref {
+                    last_deref_idx = idx;
                 }
-
-                // We are destroying the previous temp since it's no longer used.
-                if let Some(prev_temp) = prev_temp {
-                    self.patcher.add_statement(loc, StatementKind::StorageDead(prev_temp));
+            }
+            for (idx, (p_ref, p_elem)) in place.iter_projections().enumerate() {
+                if !p_ref.projection.is_empty() && p_elem == ProjectionElem::Deref {
+                    let ty = p_ref.ty(&self.local_decls, self.tcx).ty;
+                    let temp = self.patcher.new_local_with_info(
+                        ty,
+                        self.local_decls[p_ref.local].source_info.span,
+                        Some(Box::new(LocalInfo::DerefTemp)),
+                    );
+
+                    self.patcher.add_statement(loc, StatementKind::StorageLive(temp));
+
+                    // We are adding current p_ref's projections to our
+                    // temp value, excluding projections we already covered.
+                    let deref_place = Place::from(place_local)
+                        .project_deeper(&p_ref.projection[last_len..], self.tcx);
+
+                    self.patcher.add_assign(
+                        loc,
+                        Place::from(temp),
+                        Rvalue::Use(Operand::Move(deref_place)),
+                    );
+                    place_local = temp;
+                    last_len = p_ref.projection.len();
+
+                    // Change `Place` only if we are actually at the Place's last deref
+                    if idx == last_deref_idx {
+                        let temp_place =
+                            Place::from(temp).project_deeper(&place.projection[idx..], self.tcx);
+                        *place = temp_place;
+                    }
+
+                    // We are destroying the previous temp since it's no longer used.
+                    if let Some(prev_temp) = prev_temp {
+                        self.patcher.add_statement(loc, StatementKind::StorageDead(prev_temp));
+                    }
+
+                    prev_temp = Some(temp);
                 }
-
-                prev_temp = Some(temp);
             }
-        }
 
-        // Since we won't be able to reach final temp, we destroy it outside the loop.
-        if let Some(prev_temp) = prev_temp {
-            let last_loc = Location { block: loc.block, statement_index: loc.statement_index + 1 };
-            self.patcher.add_statement(last_loc, StatementKind::StorageDead(prev_temp));
+            // Since we won't be able to reach final temp, we destroy it outside the loop.
+            if let Some(prev_temp) = prev_temp {
+                let last_loc =
+                    Location { block: loc.block, statement_index: loc.statement_index + 1 };
+                self.patcher.add_statement(last_loc, StatementKind::StorageDead(prev_temp));
+            }
         }
     }
 }
@@ -92,5 +99,6 @@ pub fn deref_finder<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
 impl<'tcx> MirPass<'tcx> for Derefer {
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
         deref_finder(tcx, body);
+        body.phase = MirPhase::Derefered;
     }
 }
diff --git a/compiler/rustc_mir_transform/src/generator.rs b/compiler/rustc_mir_transform/src/generator.rs
index 4a3505ca3ff..9eb77f60213 100644
--- a/compiler/rustc_mir_transform/src/generator.rs
+++ b/compiler/rustc_mir_transform/src/generator.rs
@@ -49,6 +49,7 @@
 //! For generators with state 1 (returned) and state 2 (poisoned) it does nothing.
 //! Otherwise it drops all the values in scope at the last suspension point.
 
+use crate::deref_separator::deref_finder;
 use crate::simplify;
 use crate::util::expand_aggregate;
 use crate::MirPass;
@@ -1368,6 +1369,9 @@ impl<'tcx> MirPass<'tcx> for StateTransform {
 
         // Create the Generator::resume function
         create_generator_resume_function(tcx, transform, body, can_return);
+
+        // Run derefer to fix Derefs that are not in the first place
+        deref_finder(tcx, body);
     }
 }
 
diff --git a/compiler/rustc_mir_transform/src/inline.rs b/compiler/rustc_mir_transform/src/inline.rs
index 66fb01bd464..9526c0acc66 100644
--- a/compiler/rustc_mir_transform/src/inline.rs
+++ b/compiler/rustc_mir_transform/src/inline.rs
@@ -1,5 +1,5 @@
 //! Inlining pass for MIR functions
-
+use crate::deref_separator::deref_finder;
 use rustc_attr::InlineAttr;
 use rustc_index::bit_set::BitSet;
 use rustc_index::vec::Idx;
@@ -53,6 +53,7 @@ impl<'tcx> MirPass<'tcx> for Inline {
             debug!("running simplify cfg on {:?}", body.source);
             CfgSimplifier::new(body).simplify();
             remove_dead_blocks(tcx, body);
+            deref_finder(tcx, body);
         }
     }
 }
diff --git a/compiler/rustc_parse/src/parser/item.rs b/compiler/rustc_parse/src/parser/item.rs
index e99347206fe..6720399aacb 100644
--- a/compiler/rustc_parse/src/parser/item.rs
+++ b/compiler/rustc_parse/src/parser/item.rs
@@ -996,35 +996,24 @@ impl<'a> Parser<'a> {
     fn parse_item_foreign_mod(
         &mut self,
         attrs: &mut Vec<Attribute>,
-        unsafety: Unsafe,
+        mut unsafety: Unsafe,
     ) -> PResult<'a, ItemInfo> {
-        let sp_start = self.prev_token.span;
         let abi = self.parse_abi(); // ABI?
-        match self.parse_item_list(attrs, |p| p.parse_foreign_item(ForceCollect::No)) {
-            Ok(items) => {
-                let module = ast::ForeignMod { unsafety, abi, items };
-                Ok((Ident::empty(), ItemKind::ForeignMod(module)))
-            }
-            Err(mut err) => {
-                let current_qual_sp = self.prev_token.span;
-                let current_qual_sp = current_qual_sp.to(sp_start);
-                if let Ok(current_qual) = self.span_to_snippet(current_qual_sp) {
-                    // FIXME(davidtwco): avoid depending on the error message text
-                    if err.message[0].0.expect_str() == "expected `{`, found keyword `unsafe`" {
-                        let invalid_qual_sp = self.token.uninterpolated_span();
-                        let invalid_qual = self.span_to_snippet(invalid_qual_sp).unwrap();
-
-                        err.span_suggestion(
-                                current_qual_sp.to(invalid_qual_sp),
-                                &format!("`{}` must come before `{}`", invalid_qual, current_qual),
-                                format!("{} {}", invalid_qual, current_qual),
-                                Applicability::MachineApplicable,
-                            ).note("keyword order for functions declaration is `pub`, `default`, `const`, `async`, `unsafe`, `extern`");
-                    }
-                }
-                Err(err)
-            }
+        if unsafety == Unsafe::No
+            && self.token.is_keyword(kw::Unsafe)
+            && self.look_ahead(1, |t| t.kind == token::OpenDelim(Delimiter::Brace))
+        {
+            let mut err = self.expect(&token::OpenDelim(Delimiter::Brace)).unwrap_err();
+            err.emit();
+            unsafety = Unsafe::Yes(self.token.span);
+            self.eat_keyword(kw::Unsafe);
         }
+        let module = ast::ForeignMod {
+            unsafety,
+            abi,
+            items: self.parse_item_list(attrs, |p| p.parse_foreign_item(ForceCollect::No))?,
+        };
+        Ok((Ident::empty(), ItemKind::ForeignMod(module)))
     }
 
     /// Parses a foreign item (one in an `extern { ... }` block).
diff --git a/compiler/rustc_typeck/src/check/check.rs b/compiler/rustc_typeck/src/check/check.rs
index 09854336599..7499e5efdee 100644
--- a/compiler/rustc_typeck/src/check/check.rs
+++ b/compiler/rustc_typeck/src/check/check.rs
@@ -105,12 +105,6 @@ pub(super) fn check_fn<'a, 'tcx>(
             DUMMY_SP,
             param_env,
         ));
-    // HACK(oli-obk): we rewrite the declared return type, too, so that we don't end up inferring all
-    // unconstrained RPIT to have `()` as their hidden type. This would happen because further down we
-    // compare the ret_coercion with declared_ret_ty, and anything uninferred would be inferred to the
-    // opaque type itself. That again would cause writeback to assume we have a recursive call site
-    // and do the sadly stabilized fallback to `()`.
-    let declared_ret_ty = ret_ty;
     fcx.ret_coercion = Some(RefCell::new(CoerceMany::new(ret_ty)));
     fcx.ret_type_span = Some(decl.output.span());
 
@@ -254,7 +248,12 @@ pub(super) fn check_fn<'a, 'tcx>(
             fcx.next_ty_var(TypeVariableOrigin { kind: TypeVariableOriginKind::DynReturnFn, span });
         debug!("actual_return_ty replaced with {:?}", actual_return_ty);
     }
-    fcx.demand_suptype(span, declared_ret_ty, actual_return_ty);
+
+    // HACK(oli-obk, compiler-errors): We should be comparing this against
+    // `declared_ret_ty`, but then anything uninferred would be inferred to
+    // the opaque type itself. That again would cause writeback to assume
+    // we have a recursive call site and do the sadly stabilized fallback to `()`.
+    fcx.demand_suptype(span, ret_ty, actual_return_ty);
 
     // Check that a function marked as `#[panic_handler]` has signature `fn(&PanicInfo) -> !`
     if let Some(panic_impl_did) = tcx.lang_items().panic_impl()