Readjust constant evaluation for operands

Author: spastorino

src/librustc_codegen_ssa/mir/constant.rs

@@ -5,10 +5,33 @@ use rustc::ty::{self, Ty};
 use rustc::ty::layout::{self, HasTyCtxt};
 use syntax::source_map::Span;
 use crate::traits::*;
+use crate::mir::operand::OperandRef;
 
 use super::FunctionCx;
 
 impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
+    pub fn eval_mir_constant_to_operand(
+        &mut self,
+        bx: &mut Bx,
+        constant: &mir::Constant<'tcx>,
+    ) -> Result<OperandRef<'tcx, Bx::Value>, ErrorHandled> {
+        match constant.literal.val {
+            mir::interpret::ConstValue::Unevaluated(def_id, substs)
+                if self.cx.tcx().is_static(def_id) => {
+                    assert!(substs.is_empty(), "we don't support generic statics yet");
+                    let static_ = bx.get_static(def_id);
+                    // we treat operands referring to statics as if they were `&STATIC` instead
+                    let ptr_ty = self.cx.tcx().mk_mut_ptr(self.monomorphize(&constant.literal.ty));
+                    let layout = bx.layout_of(ptr_ty);
+                    Ok(OperandRef::from_immediate_or_packed_pair(bx, static_, layout))
+                }
+            _ => {
+                let val = self.eval_mir_constant(constant)?;
+                Ok(OperandRef::from_const(bx, val))
+            }
+        }
+    }
+
     pub fn eval_mir_constant(
         &mut self,
         constant: &mir::Constant<'tcx>,

src/librustc_codegen_ssa/mir/operand.rs

@@ -465,8 +465,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
             }
 
             mir::Operand::Constant(ref constant) => {
-                self.eval_mir_constant(constant)
-                    .map(|c| OperandRef::from_const(bx, c))
+                self.eval_mir_constant_to_operand(bx, constant)
                     .unwrap_or_else(|err| {
                         match err {
                             // errored or at least linted