Fix evil TableGen bug in template parameters with defaults.

If a TableGen class has an initializer expression containing an X.Y subexpression,
AND X depends on template parameters,
AND those template parameters have defaults,
AND some parameters with defaults are beyond position 1,
THEN parts of the initializer expression are evaluated prematurely with the default values when the first explicit template parameter is substituted, before the remaining explicit template parameters have been substituted.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@99492 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 43 insertions, 0 deletions

diff --git a/test/TableGen/2010-03-24-PrematureDefaults.td b/test/TableGen/2010-03-24-PrematureDefaults.td
new file mode 100644
index 0000000000..42f2632ab8
--- /dev/null
+++ b/test/TableGen/2010-03-24-PrematureDefaults.td
@@ -0,0 +1,43 @@
+// RUN: tblgen %s | FileCheck %s
+
+class A<int k, bits<2> x = 1> {
+  int K = k;
+  bits<2> Bits = x;
+}
+
+// CHECK: def a1
+// CHECK: Bits = { 0, 1 }
+def a1 : A<12>;
+
+// CHECK: def a2
+// CHECK: Bits = { 1, 0 }
+def a2 : A<13, 2>;
+
+// Here was the bug: X.Bits would get resolved to the default a1.Bits while
+// resolving the first template argument. When the second template argument
+// was processed, X would be set correctly, but Bits retained the default
+// value.
+class B<int k, A x = a1> {
+  A X = x;
+  bits<2> Bits = X.Bits;
+}
+
+// CHECK: def b1
+// CHECK: Bits = { 0, 1 }
+def b1 : B<27>;
+
+// CHECK: def b2
+// CHECK: Bits = { 1, 0 }
+def b2 : B<28, a2>;
+
+class C<A x = a1> {
+  bits<2> Bits = x.Bits;
+}
+
+// CHECK: def c1
+// CHECK: Bits = { 0, 1 }
+def c1 : C;
+
+// CHECK: def c2
+// CHECK: Bits = { 1, 0 }
+def c2 : C<a2>;