Fix handling of discriminantless univariant enums in Rust; fix bug with encoded enums

2016-10-27  Manish Goregaokar  <manish@mozilla.com>

gdb/ChangeLog:
    * rust-lang.c (rust_get_disr_info): Treat univariant enums
    without discriminants as encoded enums with a real field
    * rust-lang.c (rust_evaluate_subexp): Handle field access
    on encoded struct-like enums

gdb/testsuite/ChangeLog:
    * simple.rs: Add test for univariant enums without discriminants
    and for encoded struct-like enums
    * simple.exp: Add test expectations

2 files changed, 42 insertions, 0 deletions

diff --git a/gdb/testsuite/gdb.rust/simple.exp b/gdb/testsuite/gdb.rust/simple.exp
index 5e00b03..8e84daa 100644
--- a/gdb/testsuite/gdb.rust/simple.exp
+++ b/gdb/testsuite/gdb.rust/simple.exp
@@ -103,6 +103,11 @@ gdb_test_sequence "ptype z" "" {
 }
 gdb_test "print z.1" " = 8"
 
+gdb_test "print univariant" " = simple::Univariant::Foo{a: 1}"
+gdb_test "print univariant.a" " = 1"
+gdb_test "print univariant_anon" " = simple::UnivariantAnon::Foo\\(1\\)"
+gdb_test "print univariant_anon.0" " = 1"
+
 gdb_test_sequence "ptype simple::ByeBob" "" {
     " = struct simple::ByeBob \\("
     "  i32,"
@@ -220,3 +225,10 @@ gdb_test "print (1,)" "Tuple expressions not supported yet"
 gdb_test "print (1)" " = 1"
 
 gdb_test "print 23..97.0" "Range expression with different types"
+
+gdb_test "print (*parametrized.next.val)" \
+    " = simple::ParametrizedStruct<i32> {next: simple::ParametrizedEnum<Box<simple::ParametrizedStruct<i32>>>::Empty, value: 1}"
+gdb_test "print parametrized.next.val" \
+    " = \\(simple::ParametrizedStruct<i32> \\*\\) $hex"
+gdb_test "print parametrized" \
+    " = simple::ParametrizedStruct<i32> \\{next: simple::ParametrizedEnum<Box<simple::ParametrizedStruct<i32>>>::Val\\{val: $hex\\}, value: 0\\}"
diff --git a/gdb/testsuite/gdb.rust/simple.rs b/gdb/testsuite/gdb.rust/simple.rs
index eeff3d7..670f54e 100644
--- a/gdb/testsuite/gdb.rust/simple.rs
+++ b/gdb/testsuite/gdb.rust/simple.rs
@@ -63,6 +63,23 @@ enum SpaceSaver {
     Nothing,
 }
 
+enum Univariant {
+    Foo {a: u8}
+}
+enum UnivariantAnon {
+    Foo(u8)
+}
+
+enum ParametrizedEnum<T> {
+    Val { val: T },
+    Empty,
+}
+
+struct ParametrizedStruct<T> {
+    next: ParametrizedEnum<Box<ParametrizedStruct<T>>>,
+    value: T
+}
+
 fn main () {
     let a = ();
     let b : [i32; 0] = [];
@@ -93,6 +110,9 @@ fn main () {
     let y = HiBob {field1: 7, field2: 8};
     let z = ByeBob(7, 8);
 
+    let univariant = Univariant::Foo {a : 1};
+    let univariant_anon = UnivariantAnon::Foo(1);
+
     let slice = &w[2..3];
     let fromslice = slice[0];
     let slice2 = &slice[0..1];
@@ -117,6 +137,16 @@ fn main () {
     let custom_some = NonZeroOptimized::Value("hi".into());
     let custom_none = NonZeroOptimized::Empty;
 
+    let parametrized = ParametrizedStruct {
+        next: ParametrizedEnum::Val {
+            val: Box::new(ParametrizedStruct {
+                next: ParametrizedEnum::Empty,
+                value: 1,
+            })
+        },
+        value: 0,
+    };
+
     println!("{}, {}", x.0, x.1);        // set breakpoint here
     println!("{}", diff2(92, 45));
     empty();