Support 128-bit discriminants in debuginfo

Author: JohnTitor

src/librustc_codegen_llvm/debuginfo/metadata.rs

@@ -1019,7 +1019,7 @@ struct MemberDescription<'ll> {
     size: Size,
     align: Align,
     flags: DIFlags,
-    discriminant: Option<u64>,
+    discriminant: Option<u128>,
 }
 
 impl<'ll> MemberDescription<'ll> {
@@ -1039,7 +1039,7 @@ impl<'ll> MemberDescription<'ll> {
                 self.offset.bits(),
                 match self.discriminant {
                     None => None,
-                    Some(value) => Some(cx.const_u64(value)),
+                    Some(value) => Some(cx.const_uint_big(cx.type_i128(), value)),
                 },
                 self.flags,
                 self.type_metadata)
@@ -1418,7 +1418,7 @@ impl EnumMemberDescriptionFactory<'ll, 'tcx> {
                         align: self.layout.align.abi,
                         flags: DIFlags::FlagZero,
                         discriminant: Some(
-                            self.layout.ty.discriminant_for_variant(cx.tcx, i).unwrap().val as u64
+                            self.layout.ty.discriminant_for_variant(cx.tcx, i).unwrap().val
                         ),
                     }
                 }).collect()
@@ -1521,12 +1521,7 @@ impl EnumMemberDescriptionFactory<'ll, 'tcx> {
                             let value = (i.as_u32() as u128)
                                 .wrapping_sub(niche_variants.start().as_u32() as u128)
                                 .wrapping_add(niche_start);
-                            let value = truncate(value, discr.value.size(cx));
-                            // NOTE(eddyb) do *NOT* remove this assert, until
-                            // we pass the full 128-bit value to LLVM, otherwise
-                            // truncation will be silent and remain undetected.
-                            assert_eq!(value as u64 as u128, value);
-                            Some(value as u64)
+                            Some(truncate(value, discr.value.size(cx)))
                         };
 
                         MemberDescription {

src/test/codegen/enum-debug-niche-2.rs

@@ -9,8 +9,8 @@
 // compile-flags: -g -C no-prepopulate-passes
 
 // CHECK: {{.*}}DICompositeType{{.*}}tag: DW_TAG_variant_part,{{.*}}size: 32,{{.*}}
-// CHECK: {{.*}}DIDerivedType{{.*}}tag: DW_TAG_member,{{.*}}name: "Placeholder",{{.*}}extraData: i64 4294967295{{[,)].*}}
-// CHECK: {{.*}}DIDerivedType{{.*}}tag: DW_TAG_member,{{.*}}name: "Error",{{.*}}extraData: i64 0{{[,)].*}}
+// CHECK: {{.*}}DIDerivedType{{.*}}tag: DW_TAG_member,{{.*}}name: "Placeholder",{{.*}}extraData: i128 4294967295{{[,)].*}}
+// CHECK: {{.*}}DIDerivedType{{.*}}tag: DW_TAG_member,{{.*}}name: "Error",{{.*}}extraData: i128 0{{[,)].*}}
 
 #![feature(never_type)]
 

src/test/codegen/repr-u128.rs

@@ -0,0 +1,24 @@
+// ignore-tidy-linelength
+// ignore-windows
+// min-system-llvm-version 8.0
+
+// compile-flags: -g -C no-prepopulate-passes
+
+// CHECK: {{.*}}DIDerivedType{{.*}}tag: DW_TAG_member,{{.*}}name: "None",{{.*}}extraData: i128 18446745000000000124{{[,)].*}}
+
+#![feature(repr128)]
+
+#[repr(u128)]
+pub enum Foo {
+    Lo,
+    Hi = 1 << 64,
+    Bar = 18_446_745_000_000_000_123,
+}
+
+pub fn foo() -> Option<Foo> {
+    None
+}
+
+fn main() {
+    let roa = foo();
+}

src/test/debuginfo/issue-22656.rs

@@ -15,7 +15,7 @@
 // lldbg-check:[...]$0 = vec![1, 2, 3]
 // lldbr-check:(alloc::vec::Vec<i32>) v = vec![1, 2, 3]
 // lldb-command:print zs
-// lldbg-check:[...]$1 = StructWithZeroSizedField { x: ZeroSizedStruct, y: 123, z: ZeroSizedStruct, w: 456 }
+// lldbg-check:[...]$1 = StructWithZeroSizedField { x: ZeroSizedStruct { }, y: 123, z: ZeroSizedStruct { }, w: 456 }
 // lldbr-check:(issue_22656::StructWithZeroSizedField) zs = StructWithZeroSizedField { x: ZeroSizedStruct { }, y: 123, z: ZeroSizedStruct { }, w: 456 }
 // lldbr-command:continue
 

src/test/debuginfo/repr-u128.rs

@@ -0,0 +1,37 @@
+// ignore-windows
+// ignore-tidy-linelength
+// min-system-llvm-version 8.0
+
+// compile-flags: -g -C no-prepopulate-passes
+
+// === GDB TESTS ===================================================================================
+
+// gdb-command: run
+
+// gdb-command:print vals
+// gdb-check:$1 = (core::option::Option<repr_u128::Foo>, core::option::Option<repr_u128::Foo>)
+
+// === LLDB TESTS ==================================================================================
+
+// lldb-command:run
+
+// lldb-command:print vals
+// lldbg-check:[...]$0 = (Option<repr_u128::Foo> { }, Option<repr_u128::Foo> { })
+// lldbr-check:((core::option::Option<repr_u128::Foo>, core::option::Option<repr_u128::Foo>)) $0 = (Option<repr_u128::Foo> { }, Option<repr_u128::Foo> { })
+
+#![feature(repr128)]
+
+#[repr(u128)]
+pub enum Foo {
+    Lo,
+    Hi = 1 << 64,
+    Bar = 18_446_745_000_000_000_123,
+}
+
+fn main() {
+    let vals = (Some(Foo::Lo), None::<Foo>);
+
+    zzz(); // #break
+}
+
+fn zzz() {()}