Rollup merge of rust-lang#41232 - arielb1:mir-rvalues, r=eddyb

move rvalue checking to MIR

Author: TimNN

src/librustc/ich/impls_mir.rs

@@ -22,7 +22,8 @@ impl_stable_hash_for!(struct mir::SourceInfo { span, scope });
 impl_stable_hash_for!(enum mir::Mutability { Mut, Not });
 impl_stable_hash_for!(enum mir::BorrowKind { Shared, Unique, Mut });
 impl_stable_hash_for!(enum mir::LocalKind { Var, Temp, Arg, ReturnPointer });
-impl_stable_hash_for!(struct mir::LocalDecl<'tcx> { mutability, ty, name, source_info });
+impl_stable_hash_for!(struct mir::LocalDecl<'tcx> { mutability, ty, name, source_info,
+is_user_variable});
 impl_stable_hash_for!(struct mir::UpvarDecl { debug_name, by_ref });
 impl_stable_hash_for!(struct mir::BasicBlockData<'tcx> { statements, terminator, is_cleanup });
 impl_stable_hash_for!(struct mir::Terminator<'tcx> { source_info, kind });

src/librustc/mir/mod.rs

@@ -197,10 +197,10 @@ impl<'tcx> Mir<'tcx> {
     pub fn temps_iter<'a>(&'a self) -> impl Iterator<Item=Local> + 'a {
         (self.arg_count+1..self.local_decls.len()).filter_map(move |index| {
             let local = Local::new(index);
-            if self.local_decls[local].source_info.is_none() {
-                Some(local)
-            } else {
+            if self.local_decls[local].is_user_variable {
                 None
+            } else {
+                Some(local)
             }
         })
     }
@@ -210,10 +210,10 @@ impl<'tcx> Mir<'tcx> {
     pub fn vars_iter<'a>(&'a self) -> impl Iterator<Item=Local> + 'a {
         (self.arg_count+1..self.local_decls.len()).filter_map(move |index| {
             let local = Local::new(index);
-            if self.local_decls[local].source_info.is_none() {
-                None
-            } else {
+            if self.local_decls[local].is_user_variable {
                 Some(local)
+            } else {
+                None
             }
         })
     }
@@ -370,6 +370,9 @@ pub struct LocalDecl<'tcx> {
     /// Temporaries and the return pointer are always mutable.
     pub mutability: Mutability,
 
+    /// True if this corresponds to a user-declared local variable.
+    pub is_user_variable: bool,
+
     /// Type of this local.
     pub ty: Ty<'tcx>,
 
@@ -379,37 +382,40 @@ pub struct LocalDecl<'tcx> {
     /// to generate better debuginfo.
     pub name: Option<Name>,
 
-    /// For user-declared variables, stores their source information.
-    ///
-    /// For temporaries, this is `None`.
-    ///
-    /// This is the primary way to differentiate between user-declared
-    /// variables and compiler-generated temporaries.
-    pub source_info: Option<SourceInfo>,
+    /// Source info of the local.
+    pub source_info: SourceInfo,
 }
 
 impl<'tcx> LocalDecl<'tcx> {
     /// Create a new `LocalDecl` for a temporary.
     #[inline]
-    pub fn new_temp(ty: Ty<'tcx>) -> Self {
+    pub fn new_temp(ty: Ty<'tcx>, span: Span) -> Self {
         LocalDecl {
             mutability: Mutability::Mut,
             ty: ty,
             name: None,
-            source_info: None,
+            source_info: SourceInfo {
+                span: span,
+                scope: ARGUMENT_VISIBILITY_SCOPE
+            },
+            is_user_variable: false
         }
     }
 
     /// Builds a `LocalDecl` for the return pointer.
     ///
     /// This must be inserted into the `local_decls` list as the first local.
     #[inline]
-    pub fn new_return_pointer(return_ty: Ty) -> LocalDecl {
+    pub fn new_return_pointer(return_ty: Ty, span: Span) -> LocalDecl {
         LocalDecl {
             mutability: Mutability::Mut,
             ty: return_ty,
-            source_info: None,
+            source_info: SourceInfo {
+                span: span,
+                scope: ARGUMENT_VISIBILITY_SCOPE
+            },
             name: None,     // FIXME maybe we do want some name here?
+            is_user_variable: false
         }
     }
 }

src/librustc/mir/visit.rs

@@ -630,12 +630,11 @@ macro_rules! make_mir_visitor {
                     ref $($mutability)* ty,
                     name: _,
                     ref $($mutability)* source_info,
+                    is_user_variable: _,
                 } = *local_decl;
 
                 self.visit_ty(ty);
-                if let Some(ref $($mutability)* info) = *source_info {
-                    self.visit_source_info(info);
-                }
+                self.visit_source_info(source_info);
             }
 
             fn super_visibility_scope(&mut self,

src/librustc_borrowck/borrowck/mir/elaborate_drops.rs

@@ -307,12 +307,12 @@ impl<'b, 'tcx> ElaborateDropsCtxt<'b, 'tcx> {
         data
     }
 
-    fn create_drop_flag(&mut self, index: MovePathIndex) {
+    fn create_drop_flag(&mut self, index: MovePathIndex, span: Span) {
         let tcx = self.tcx;
         let patch = &mut self.patch;
         debug!("create_drop_flag({:?})", self.mir.span);
         self.drop_flags.entry(index).or_insert_with(|| {
-            patch.new_temp(tcx.types.bool)
+            patch.new_temp(tcx.types.bool, span)
         });
     }
 
@@ -374,7 +374,7 @@ impl<'b, 'tcx> ElaborateDropsCtxt<'b, 'tcx> {
                 debug!("collect_drop_flags: collecting {:?} from {:?}@{:?} - {:?}",
                        child, location, path, (maybe_live, maybe_dead));
                 if maybe_live && maybe_dead {
-                    self.create_drop_flag(child)
+                    self.create_drop_flag(child, terminator.source_info.span)
                 }
             });
         }

src/librustc_driver/driver.rs

@@ -35,7 +35,7 @@ use rustc_typeck as typeck;
 use rustc_privacy;
 use rustc_plugin::registry::Registry;
 use rustc_plugin as plugin;
-use rustc_passes::{ast_validation, no_asm, loops, consts, rvalues,
+use rustc_passes::{ast_validation, no_asm, loops, consts,
                    static_recursion, hir_stats, mir_stats};
 use rustc_const_eval::check_match;
 use super::Compilation;
@@ -958,10 +958,6 @@ pub fn phase_3_run_analysis_passes<'tcx, F, R>(sess: &'tcx Session,
              "liveness checking",
              || middle::liveness::check_crate(tcx));
 
-        time(time_passes,
-             "rvalue checking",
-             || rvalues::check_crate(tcx));
-
         time(time_passes,
              "MIR dump",
              || mir::mir_map::build_mir_for_crate(tcx));
@@ -977,8 +973,8 @@ pub fn phase_3_run_analysis_passes<'tcx, F, R>(sess: &'tcx Session,
             // in stage 4 below.
             passes.push_hook(box mir::transform::dump_mir::DumpMir);
             passes.push_pass(box mir::transform::simplify::SimplifyCfg::new("initial"));
-            passes.push_pass(box mir::transform::qualify_consts::QualifyAndPromoteConstants);
             passes.push_pass(box mir::transform::type_check::TypeckMir);
+            passes.push_pass(box mir::transform::qualify_consts::QualifyAndPromoteConstants);
             passes.push_pass(
                 box mir::transform::simplify_branches::SimplifyBranches::new("initial"));
             passes.push_pass(box mir::transform::simplify::SimplifyCfg::new("qualify-consts"));

src/librustc_mir/build/expr/as_lvalue.rs

@@ -62,7 +62,8 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                 let idx = unpack!(block = this.as_operand(block, None, index));
 
                 // bounds check:
-                let (len, lt) = (this.temp(usize_ty.clone()), this.temp(bool_ty));
+                let (len, lt) = (this.temp(usize_ty.clone(), expr_span),
+                                 this.temp(bool_ty, expr_span));
                 this.cfg.push_assign(block, source_info, // len = len(slice)
                                      &len, Rvalue::Len(slice.clone()));
                 this.cfg.push_assign(block, source_info, // lt = idx < len

src/librustc_mir/build/expr/as_rvalue.rs

@@ -82,7 +82,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                     let bool_ty = this.hir.bool_ty();
 
                     let minval = this.minval_literal(expr_span, expr.ty);
-                    let is_min = this.temp(bool_ty);
+                    let is_min = this.temp(bool_ty, expr_span);
 
                     this.cfg.push_assign(block, source_info, &is_min,
                                          Rvalue::BinaryOp(BinOp::Eq, arg.clone(), minval));
@@ -95,7 +95,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
             }
             ExprKind::Box { value, value_extents } => {
                 let value = this.hir.mirror(value);
-                let result = this.temp(expr.ty);
+                let result = this.temp(expr.ty, expr_span);
                 // to start, malloc some memory of suitable type (thus far, uninitialized):
                 this.cfg.push_assign(block, source_info, &result, Rvalue::Box(value.ty));
                 this.in_scope(value_extents, block, |this| {
@@ -260,7 +260,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
         let bool_ty = self.hir.bool_ty();
         if self.hir.check_overflow() && op.is_checkable() && ty.is_integral() {
             let result_tup = self.hir.tcx().intern_tup(&[ty, bool_ty], false);
-            let result_value = self.temp(result_tup);
+            let result_value = self.temp(result_tup, span);
 
             self.cfg.push_assign(block, source_info,
                                  &result_value, Rvalue::CheckedBinaryOp(op,
@@ -301,7 +301,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                 };
 
                 // Check for / 0
-                let is_zero = self.temp(bool_ty);
+                let is_zero = self.temp(bool_ty, span);
                 let zero = self.zero_literal(span, ty);
                 self.cfg.push_assign(block, source_info, &is_zero,
                                      Rvalue::BinaryOp(BinOp::Eq, rhs.clone(), zero));
@@ -315,9 +315,9 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                     let neg_1 = self.neg_1_literal(span, ty);
                     let min = self.minval_literal(span, ty);
 
-                    let is_neg_1 = self.temp(bool_ty);
-                    let is_min   = self.temp(bool_ty);
-                    let of       = self.temp(bool_ty);
+                    let is_neg_1 = self.temp(bool_ty, span);
+                    let is_min   = self.temp(bool_ty, span);
+                    let of       = self.temp(bool_ty, span);
 
                     // this does (rhs == -1) & (lhs == MIN). It could short-circuit instead
 

src/librustc_mir/build/expr/as_temp.rs

@@ -44,8 +44,8 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
         }
 
         let expr_ty = expr.ty.clone();
-        let temp = this.temp(expr_ty.clone());
         let expr_span = expr.span;
+        let temp = this.temp(expr_ty.clone(), expr_span);
         let source_info = this.source_info(expr_span);
 
         if expr.temp_lifetime_was_shrunk && this.hir.needs_drop(expr_ty) {

src/librustc_mir/build/expr/stmt.rs

@@ -138,7 +138,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
             }
             _ => {
                 let expr_ty = expr.ty;
-                let temp = this.temp(expr.ty.clone());
+                let temp = this.temp(expr.ty.clone(), expr_span);
                 unpack!(block = this.into(&temp, block, expr));
                 unpack!(block = this.build_drop(block, expr_span, temp, expr_ty));
                 block.unit()

src/librustc_mir/build/matches/mod.rs

@@ -710,7 +710,8 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
             mutability: mutability,
             ty: var_ty.clone(),
             name: Some(name),
-            source_info: Some(source_info),
+            source_info: source_info,
+            is_user_variable: true,
         });
         self.var_indices.insert(var_id, var);
 

src/librustc_mir/build/matches/test.rs

@@ -210,7 +210,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                 debug!("num_enum_variants: {}, tested variants: {:?}, variants: {:?}",
                        num_enum_variants, values, variants);
                 let discr_ty = adt_def.repr.discr_type().to_ty(tcx);
-                let discr = self.temp(discr_ty);
+                let discr = self.temp(discr_ty, test.span);
                 self.cfg.push_assign(block, source_info, &discr,
                                      Rvalue::Discriminant(lvalue.clone()));
                 assert_eq!(values.len() + 1, targets.len());
@@ -270,7 +270,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                     if let ty::TyRef(region, mt) = ty.sty {
                         if let ty::TyArray(_, _) = mt.ty.sty {
                             ty = tcx.mk_imm_ref(region, tcx.mk_slice(tcx.types.u8));
-                            let val_slice = self.temp(ty);
+                            let val_slice = self.temp(ty, test.span);
                             self.cfg.push_assign(block, source_info, &val_slice,
                                                  Rvalue::Cast(CastKind::Unsize, val, ty));
                             val = Operand::Consume(val_slice);
@@ -285,7 +285,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                         value: value.clone()
                     });
 
-                    let slice = self.temp(ty);
+                    let slice = self.temp(ty, test.span);
                     self.cfg.push_assign(block, source_info, &slice,
                                          Rvalue::Cast(CastKind::Unsize, array, ty));
                     Operand::Consume(slice)
@@ -304,7 +304,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                     let (mty, method) = self.hir.trait_method(eq_def_id, "eq", ty, &[ty]);
 
                     let bool_ty = self.hir.bool_ty();
-                    let eq_result = self.temp(bool_ty);
+                    let eq_result = self.temp(bool_ty, test.span);
                     let eq_block = self.cfg.start_new_block();
                     let cleanup = self.diverge_cleanup();
                     self.cfg.terminate(block, source_info, TerminatorKind::Call {
@@ -349,7 +349,8 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
 
             TestKind::Len { len, op } => {
                 let (usize_ty, bool_ty) = (self.hir.usize_ty(), self.hir.bool_ty());
-                let (actual, result) = (self.temp(usize_ty), self.temp(bool_ty));
+                let (actual, result) = (self.temp(usize_ty, test.span),
+                                        self.temp(bool_ty, test.span));
 
                 // actual = len(lvalue)
                 self.cfg.push_assign(block, source_info,
@@ -383,7 +384,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                left: Operand<'tcx>,
                right: Operand<'tcx>) -> BasicBlock {
         let bool_ty = self.hir.bool_ty();
-        let result = self.temp(bool_ty);
+        let result = self.temp(bool_ty, span);
 
         // result = op(left, right)
         let source_info = self.source_info(span);

src/librustc_mir/build/misc.rs

@@ -27,8 +27,8 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
     ///
     /// NB: **No cleanup is scheduled for this temporary.** You should
     /// call `schedule_drop` once the temporary is initialized.
-    pub fn temp(&mut self, ty: Ty<'tcx>) -> Lvalue<'tcx> {
-        let temp = self.local_decls.push(LocalDecl::new_temp(ty));
+    pub fn temp(&mut self, ty: Ty<'tcx>, span: Span) -> Lvalue<'tcx> {
+        let temp = self.local_decls.push(LocalDecl::new_temp(ty, span));
         let lvalue = Lvalue::Local(temp);
         debug!("temp: created temp {:?} with type {:?}",
                lvalue, self.local_decls[temp].ty);
@@ -106,7 +106,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                       value: u64)
                       -> Lvalue<'tcx> {
         let usize_ty = self.hir.usize_ty();
-        let temp = self.temp(usize_ty);
+        let temp = self.temp(usize_ty, source_info.span);
         self.cfg.push_assign_constant(
             block, source_info, &temp,
             Constant {

src/librustc_mir/build/mod.rs

@@ -249,7 +249,8 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
             visibility_scopes: IndexVec::new(),
             visibility_scope: ARGUMENT_VISIBILITY_SCOPE,
             breakable_scopes: vec![],
-            local_decls: IndexVec::from_elem_n(LocalDecl::new_return_pointer(return_ty), 1),
+            local_decls: IndexVec::from_elem_n(LocalDecl::new_return_pointer(return_ty,
+                                                                             span), 1),
             var_indices: NodeMap(),
             unit_temp: None,
             cached_resume_block: None,
@@ -304,8 +305,12 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
             self.local_decls.push(LocalDecl {
                 mutability: Mutability::Not,
                 ty: ty,
-                source_info: None,
+                source_info: SourceInfo {
+                    scope: ARGUMENT_VISIBILITY_SCOPE,
+                    span: pattern.map_or(self.fn_span, |pat| pat.span)
+                },
                 name: name,
+                is_user_variable: false,
             });
         }
 
@@ -341,7 +346,8 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
             Some(ref tmp) => tmp.clone(),
             None => {
                 let ty = self.hir.unit_ty();
-                let tmp = self.temp(ty);
+                let fn_span = self.fn_span;
+                let tmp = self.temp(ty, fn_span);
                 self.unit_temp = Some(tmp.clone());
                 tmp
             }