Merge pull request #16613 from eeckstein/fix-jit-4.2

Author: swift-ci

lib/IRGen/GenDecl.cpp

@@ -79,6 +79,8 @@ bool IRGenerator::tryEnableLazyTypeMetadata(NominalTypeDecl *Nominal) {
   // is not used by the program itself.
   if (!Opts.shouldOptimize())
     return false;
+  if (Opts.UseJIT)
+    return false;
 
   switch (Nominal->getKind()) {
     case DeclKind::Enum:

test/Interpreter/unused-type.swift

@@ -0,0 +1,17 @@
+// RUN: %target-jit-run -O %s | %FileCheck %s
+// REQUIRES: executable_test
+// REQUIRES: swift_interpreter
+
+// Check that when running the jit with -O we don't crash with an unresolved
+// metadata symbol.
+
+protocol Foo {
+    func foo() -> Int
+}
+
+struct Dummy: Foo {
+    func foo() -> Int { return 42 }
+}
+
+// CHECK: ok
+print("ok")