Rustfmt

[rust.git] / src / discriminant.rs

diff --git a/src/discriminant.rs b/src/discriminant.rs
index 3815e149ffa1a4529608ee5129f6fee60005e4fa..f619bb5ed5e586ae33f5b7711095613bdad14472 100644 (file)
--- a/src/discriminant.rs
+++ b/src/discriminant.rs
@@ -26,11 +26,7 @@ pub(crate) fn codegen_set_discriminant<'tcx>(
             variants: _,
         } => {
             let ptr = place.place_field(fx, mir::Field::new(tag_field));
-            let to = layout
-                .ty
-                .discriminant_for_variant(fx.tcx, variant_index)
-                .unwrap()
-                .val;
+            let to = layout.ty.discriminant_for_variant(fx.tcx, variant_index).unwrap().val;
             let to = if ptr.layout().abi.is_signed() {
                 ty::ScalarInt::try_from_int(
                     ptr.layout().size.sign_extend(to) as i128,
@@ -46,12 +42,7 @@ pub(crate) fn codegen_set_discriminant<'tcx>(
         Variants::Multiple {
             tag: _,
             tag_field,
-            tag_encoding:
-                TagEncoding::Niche {
-                    dataful_variant,
-                    ref niche_variants,
-                    niche_start,
-                },
+            tag_encoding: TagEncoding::Niche { dataful_variant, ref niche_variants, niche_start },
             variants: _,
         } => {
             if variant_index != dataful_variant {
@@ -77,11 +68,10 @@ pub(crate) fn codegen_get_discriminant<'tcx>(
     let layout = value.layout();
 
     if layout.abi == Abi::Uninhabited {
-        return trap_unreachable_ret_value(
-            fx,
-            dest_layout,
-            "[panic] Tried to get discriminant for uninhabited type.",
-        );
+        let true_ = fx.bcx.ins().iconst(types::I32, 1);
+        fx.bcx.ins().trapnz(true_, TrapCode::UnreachableCodeReached);
+        // Return a dummy value
+        return CValue::by_ref(Pointer::const_addr(fx, 0), dest_layout);
     }
 
     let (tag_scalar, tag_field, tag_encoding) = match &layout.variants {
@@ -101,12 +91,9 @@ pub(crate) fn codegen_get_discriminant<'tcx>(
             };
             return CValue::const_val(fx, dest_layout, discr_val);
         }
-        Variants::Multiple {
-            tag,
-            tag_field,
-            tag_encoding,
-            variants: _,
-        } => (tag, *tag_field, tag_encoding),
+        Variants::Multiple { tag, tag_field, tag_encoding, variants: _ } => {
+            (tag, *tag_field, tag_encoding)
+        }
     };
 
     let cast_to = fx.clif_type(dest_layout.ty).unwrap();
@@ -118,18 +105,14 @@ pub(crate) fn codegen_get_discriminant<'tcx>(
     // Decode the discriminant (specifically if it's niche-encoded).
     match *tag_encoding {
         TagEncoding::Direct => {
-            let signed = match tag_scalar.value {
+            let signed = match tag_scalar.primitive() {
                 Int(_, signed) => signed,
                 _ => false,
             };
             let val = clif_intcast(fx, tag, cast_to, signed);
             CValue::by_val(val, dest_layout)
         }
-        TagEncoding::Niche {
-            dataful_variant,
-            ref niche_variants,
-            niche_start,
-        } => {
+        TagEncoding::Niche { dataful_variant, ref niche_variants, niche_start } => {
             // Rebase from niche values to discriminants, and check
             // whether the result is in range for the niche variants.
 
@@ -145,10 +128,16 @@ pub(crate) fn codegen_get_discriminant<'tcx>(
             let relative_discr = if niche_start == 0 {
                 tag
             } else {
-                // FIXME handle niche_start > i64::MAX
-                fx.bcx
-                    .ins()
-                    .iadd_imm(tag, -i64::try_from(niche_start).unwrap())
+                let niche_start = match fx.bcx.func.dfg.value_type(tag) {
+                    types::I128 => {
+                        let lsb = fx.bcx.ins().iconst(types::I64, niche_start as u64 as i64);
+                        let msb =
+                            fx.bcx.ins().iconst(types::I64, (niche_start >> 64) as u64 as i64);
+                        fx.bcx.ins().iconcat(lsb, msb)
+                    }
+                    ty => fx.bcx.ins().iconst(ty, niche_start as i64),
+                };
+                fx.bcx.ins().isub(tag, niche_start)
             };
             let relative_max = niche_variants.end().as_u32() - niche_variants.start().as_u32();
             let is_niche = {
@@ -176,15 +165,10 @@ pub(crate) fn codegen_get_discriminant<'tcx>(
                 } else {
                     clif_intcast(fx, relative_discr, cast_to, false)
                 };
-                fx.bcx
-                    .ins()
-                    .iadd_imm(relative_discr, i64::from(niche_variants.start().as_u32()))
+                fx.bcx.ins().iadd_imm(relative_discr, i64::from(niche_variants.start().as_u32()))
             };
 
-            let dataful_variant = fx
-                .bcx
-                .ins()
-                .iconst(cast_to, i64::from(dataful_variant.as_u32()));
+            let dataful_variant = fx.bcx.ins().iconst(cast_to, i64::from(dataful_variant.as_u32()));
             let discr = fx.bcx.ins().select(is_niche, niche_discr, dataful_variant);
             CValue::by_val(discr, dest_layout)
         }