Auto merge of rust-lang#63152 - estebank:big-array, r=oli-obk

Always error on `SizeOverflow` during mir evaluation

Fix rust-lang#55878, fix rust-lang#25116.

r? @oli-obk

Author: bors

src/librustc/mir/interpret/error.rs

@@ -137,17 +137,17 @@ impl<'tcx> ConstEvalErr<'tcx> {
         message: &str,
         lint_root: Option<hir::HirId>,
     ) -> Result<DiagnosticBuilder<'tcx>, ErrorHandled> {
-        match self.error {
+        let must_error = match self.error {
             err_inval!(Layout(LayoutError::Unknown(_))) |
             err_inval!(TooGeneric) =>
                 return Err(ErrorHandled::TooGeneric),
-            err_inval!(Layout(LayoutError::SizeOverflow(_))) |
             err_inval!(TypeckError) =>
                 return Err(ErrorHandled::Reported),
-            _ => {},
-        }
+            err_inval!(Layout(LayoutError::SizeOverflow(_))) => true,
+            _ => false,
+        };
         trace!("reporting const eval failure at {:?}", self.span);
-        let mut err = if let Some(lint_root) = lint_root {
+        let mut err = if let (Some(lint_root), false) = (lint_root, must_error) {
             let hir_id = self.stacktrace
                 .iter()
                 .rev()
@@ -160,10 +160,14 @@ impl<'tcx> ConstEvalErr<'tcx> {
                 tcx.span,
                 message,
             )
+        } else if must_error {
+            struct_error(tcx, &self.error.to_string())
         } else {
             struct_error(tcx, message)
         };
-        err.span_label(self.span, self.error.to_string());
+        if !must_error {
+            err.span_label(self.span, self.error.to_string());
+        }
         // Skip the last, which is just the environment of the constant.  The stacktrace
         // is sometimes empty because we create "fake" eval contexts in CTFE to do work
         // on constant values.
@@ -335,7 +339,7 @@ impl fmt::Debug for InvalidProgramInfo<'tcx> {
             TypeckError =>
                 write!(f, "encountered constants with type errors, stopping evaluation"),
             Layout(ref err) =>
-                write!(f, "rustc layout computation failed: {:?}", err),
+                write!(f, "{}", err),
         }
     }
 }

src/librustc_codegen_llvm/context.rs

@@ -30,6 +30,7 @@ use std::iter;
 use std::str;
 use std::sync::Arc;
 use syntax::symbol::LocalInternedString;
+use syntax::source_map::{DUMMY_SP, Span};
 use crate::abi::Abi;
 
 /// There is one `CodegenCx` per compilation unit. Each one has its own LLVM
@@ -860,9 +861,13 @@ impl LayoutOf for CodegenCx<'ll, 'tcx> {
     type TyLayout = TyLayout<'tcx>;
 
     fn layout_of(&self, ty: Ty<'tcx>) -> Self::TyLayout {
+        self.spanned_layout_of(ty, DUMMY_SP)
+    }
+
+    fn spanned_layout_of(&self, ty: Ty<'tcx>, span: Span) -> Self::TyLayout {
         self.tcx.layout_of(ty::ParamEnv::reveal_all().and(ty))
             .unwrap_or_else(|e| if let LayoutError::SizeOverflow(_) = e {
-                self.sess().fatal(&e.to_string())
+                self.sess().span_fatal(span, &e.to_string())
             } else {
                 bug!("failed to get layout for `{}`: {}", ty, e)
             })

src/librustc_codegen_ssa/mir/analyze.rs

@@ -9,6 +9,7 @@ use rustc::mir::visit::{Visitor, PlaceContext, MutatingUseContext, NonMutatingUs
 use rustc::mir::traversal;
 use rustc::ty;
 use rustc::ty::layout::{LayoutOf, HasTyCtxt};
+use syntax_pos::DUMMY_SP;
 use super::FunctionCx;
 use crate::traits::*;
 
@@ -20,10 +21,13 @@ pub fn non_ssa_locals<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
 
     analyzer.visit_body(mir);
 
-    for (index, ty) in mir.local_decls.iter().map(|l| l.ty).enumerate() {
+    for (index, (ty, span)) in mir.local_decls.iter()
+        .map(|l| (l.ty, l.source_info.span))
+        .enumerate()
+    {
         let ty = fx.monomorphize(&ty);
         debug!("local {} has type {:?}", index, ty);
-        let layout = fx.cx.layout_of(ty);
+        let layout = fx.cx.spanned_layout_of(ty, span);
         if fx.cx.is_backend_immediate(layout) {
             // These sorts of types are immediates that we can store
             // in an Value without an alloca.
@@ -93,10 +97,12 @@ impl<Bx: BuilderMethods<'a, 'tcx>> LocalAnalyzer<'mir, 'a, 'tcx, Bx> {
         }
     }
 
-    fn process_place(&mut self,
-                     place_ref: &mir::PlaceRef<'_, 'tcx>,
-                     context: PlaceContext,
-                     location: Location) {
+    fn process_place(
+        &mut self,
+        place_ref: &mir::PlaceRef<'_, 'tcx>,
+        context: PlaceContext,
+        location: Location,
+    ) {
         let cx = self.fx.cx;
 
         if let Some(proj) = place_ref.projection {
@@ -116,12 +122,17 @@ impl<Bx: BuilderMethods<'a, 'tcx>> LocalAnalyzer<'mir, 'a, 'tcx, Bx> {
                     .projection_ty(cx.tcx(), &proj.elem)
                     .ty;
                 let elem_ty = self.fx.monomorphize(&elem_ty);
-                if cx.layout_of(elem_ty).is_zst() {
+                let span = if let mir::PlaceBase::Local(index) = place_ref.base {
+                    self.fx.mir.local_decls[*index].source_info.span
+                } else {
+                    DUMMY_SP
+                };
+                if cx.spanned_layout_of(elem_ty, span).is_zst() {
                     return;
                 }
 
                 if let mir::ProjectionElem::Field(..) = proj.elem {
-                    let layout = cx.layout_of(base_ty.ty);
+                    let layout = cx.spanned_layout_of(base_ty.ty, span);
                     if cx.is_backend_immediate(layout) || cx.is_backend_scalar_pair(layout) {
                         // Recurse with the same context, instead of `Projection`,
                         // potentially stopping at non-operand projections,
@@ -188,7 +199,8 @@ impl<'mir, 'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> Visitor<'tcx>
             projection: None,
         } = *place {
             self.assign(index, location);
-            if !self.fx.rvalue_creates_operand(rvalue) {
+            let decl_span = self.fx.mir.local_decls[index].source_info.span;
+            if !self.fx.rvalue_creates_operand(rvalue, decl_span) {
                 self.not_ssa(index);
             }
         } else {

src/librustc_codegen_ssa/mir/rvalue.rs

@@ -6,6 +6,7 @@ use rustc::middle::lang_items::ExchangeMallocFnLangItem;
 use rustc_apfloat::{ieee, Float, Status, Round};
 use std::{u128, i128};
 use syntax::symbol::sym;
+use syntax::source_map::{DUMMY_SP, Span};
 
 use crate::base;
 use crate::MemFlags;
@@ -136,7 +137,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
             }
 
             _ => {
-                assert!(self.rvalue_creates_operand(rvalue));
+                assert!(self.rvalue_creates_operand(rvalue, DUMMY_SP));
                 let (mut bx, temp) = self.codegen_rvalue_operand(bx, rvalue);
                 temp.val.store(&mut bx, dest);
                 bx
@@ -169,7 +170,11 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         mut bx: Bx,
         rvalue: &mir::Rvalue<'tcx>
     ) -> (Bx, OperandRef<'tcx, Bx::Value>) {
-        assert!(self.rvalue_creates_operand(rvalue), "cannot codegen {:?} to operand", rvalue);
+        assert!(
+            self.rvalue_creates_operand(rvalue, DUMMY_SP),
+            "cannot codegen {:?} to operand",
+            rvalue,
+        );
 
         match *rvalue {
             mir::Rvalue::Cast(ref kind, ref source, mir_cast_ty) => {
@@ -691,7 +696,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
 }
 
 impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
-    pub fn rvalue_creates_operand(&self, rvalue: &mir::Rvalue<'tcx>) -> bool {
+    pub fn rvalue_creates_operand(&self, rvalue: &mir::Rvalue<'tcx>, span: Span) -> bool {
         match *rvalue {
             mir::Rvalue::Ref(..) |
             mir::Rvalue::Len(..) |
@@ -707,7 +712,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
             mir::Rvalue::Aggregate(..) => {
                 let ty = rvalue.ty(self.mir, self.cx.tcx());
                 let ty = self.monomorphize(&ty);
-                self.cx.layout_of(ty).is_zst()
+                self.cx.spanned_layout_of(ty, span).is_zst()
             }
         }
 

src/librustc_mir/interpret/eval_context.rs

@@ -506,7 +506,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
     pub fn push_stack_frame(
         &mut self,
         instance: ty::Instance<'tcx>,
-        span: source_map::Span,
+        span: Span,
         body: &'mir mir::Body<'tcx>,
         return_place: Option<PlaceTy<'tcx, M::PointerTag>>,
         return_to_block: StackPopCleanup,

src/librustc_target/abi/mod.rs

@@ -9,6 +9,7 @@ use std::ops::{Add, Deref, Sub, Mul, AddAssign, Range, RangeInclusive};
 use rustc_data_structures::newtype_index;
 use rustc_data_structures::indexed_vec::{Idx, IndexVec};
 use syntax_pos::symbol::{sym, Symbol};
+use syntax_pos::Span;
 
 pub mod call;
 
@@ -1012,6 +1013,9 @@ pub trait LayoutOf {
     type TyLayout;
 
     fn layout_of(&self, ty: Self::Ty) -> Self::TyLayout;
+    fn spanned_layout_of(&self, ty: Self::Ty, _span: Span) -> Self::TyLayout {
+        self.layout_of(ty)
+    }
 }
 
 #[derive(Copy, Clone, PartialEq, Eq)]

src/test/compile-fail/const-err3.rs renamed to src/test/compile-fail/consts/const-err3.rs

@@ -0,0 +1,7 @@
+// normalize-stderr-64bit "18446744073709551615" -> "SIZE"
+// normalize-stderr-32bit "4294967295" -> "SIZE"
+
+// error-pattern: is too big for the current architecture
+fn main() {
+    println!("Size: {}", std::mem::size_of::<[u8; std::u64::MAX as usize]>());
+}

src/test/compile-fail/const-fn-error.rs renamed to src/test/compile-fail/consts/const-fn-error.rs

@@ -0,0 +1,11 @@
+// ignore-64bit
+
+// FIXME https://github.com/rust-lang/rust/issues/59774
+// normalize-stderr-test "thread.*panicked.*Metadata module not compiled.*\n" -> ""
+// normalize-stderr-test "note:.*RUST_BACKTRACE=1.*\n" -> ""
+#![allow(exceeding_bitshifts)]
+
+fn main() {
+    let _fat: [u8; (1<<31)+(1<<15)] = //~ ERROR too big for the current architecture
+        [0; (1u32<<31) as usize +(1u32<<15) as usize];
+}