1 files changed, 83 insertions, 0 deletions
diff --git a/test/Tooling/clang-diff-topdown.cpp b/test/Tooling/clang-diff-topdown.cpp
new file mode 100644
index 0000000000000..d6c1d770333ba
--- /dev/null
+++ b/test/Tooling/clang-diff-topdown.cpp
@@ -0,0 +1,83 @@
+// RUN: %clang_cc1 -E %s > %t.src.cpp
+// RUN: %clang_cc1 -E %s > %t.dst.cpp -DDEST
+// RUN: clang-diff -dump-matches -stop-diff-after=topdown %t.src.cpp %t.dst.cpp -- -std=c++11 | FileCheck %s
+//
+// Test the top-down matching of identical subtrees only.
+
+#ifndef DEST
+
+void f1()
+{
+  // Match some subtree of height greater than 2.
+  // CHECK: Match CompoundStmt(3) to CompoundStmt(3)
+  // CHECK: Match CompoundStmt(4) to CompoundStmt(4)
+  // CHECK: Match NullStmt(5) to NullStmt(5)
+  {{;}}
+
+  // Don't match subtrees that are smaller.
+  // CHECK-NOT: Match CompoundStmt(6)
+  // CHECK-NOT: Match NullStmt(7)
+  {;}
+
+  // Greedy approach - use the first matching subtree when there are multiple
+  // identical subtrees.
+  // CHECK: Match CompoundStmt(8) to CompoundStmt(8)
+  // CHECK: Match CompoundStmt(9) to CompoundStmt(9)
+  // CHECK: Match NullStmt(10) to NullStmt(10)
+  {{;;}}
+}
+
+int x;
+
+namespace src {
+  int x;
+  int x1 = x + 1;
+  int x2 = ::x + 1;
+}
+
+class A { int x = 1 + 1; void f() { int x1 = x; } };
+
+#else
+
+
+void f1() {
+
+  {{;}}
+
+  {;}
+
+  {{;;}}
+  // CHECK-NOT: Match {{.*}} to CompoundStmt(11)
+  // CHECK-NOT: Match {{.*}} to CompoundStmt(12)
+  // CHECK-NOT: Match {{.*}} to NullStmt(13)
+  {{;;}}
+
+  // CHECK-NOT: Match {{.*}} to NullStmt(14)
+  ;
+}
+
+int x;
+
+namespace dst {
+  int x;
+  // CHECK: Match DeclRefExpr: :x(17) to DeclRefExpr: :x(22)
+  int x1 = x + 1;
+  // CHECK: Match DeclRefExpr: x(21) to DeclRefExpr: x(26)
+  int x2 = ::x + 1;
+}
+
+class B {
+  // Only the class name changed; it is not included in the field value,
+  // therefore there is no update.
+  // CHECK: Match FieldDecl: :x(int)(24) to FieldDecl: :x(int)(29)
+  // CHECK-NOT: Update FieldDecl: :x(int)(24)
+  int x = 1+1;
+  void f() {
+    // CHECK: Match MemberExpr: :x(32) to MemberExpr: :x(37)
+    // CHECK-NOT: Update MemberExpr: :x(32)
+    int x1 = B::x;
+  }
+
+};
+
+#endif