--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/clang/test/Sema/attr-enforce-tcb.c	Tue Jun 08 06:07:14 2021 +0900
@@ -0,0 +1,65 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+
+#define PLACE_IN_TCB(NAME) __attribute__ ((enforce_tcb(NAME)))
+#define PLACE_IN_TCB_LEAF(NAME) __attribute__ ((enforce_tcb_leaf(NAME)))
+
+void foo1 (void) PLACE_IN_TCB("bar");
+void foo2 (void) PLACE_IN_TCB("bar");
+void foo3 (void); // not in any TCB
+void foo4 (void) PLACE_IN_TCB("bar2");
+void foo5 (void) PLACE_IN_TCB_LEAF("bar");
+void foo6 (void) PLACE_IN_TCB("bar2") PLACE_IN_TCB("bar");
+void foo7 (void) PLACE_IN_TCB("bar3");
+void foo8 (void) PLACE_IN_TCB("bar") PLACE_IN_TCB("bar2");
+void foo9 (void);
+
+void foo1() {
+    foo2(); // OK - function in same TCB
+    foo3(); // expected-warning {{calling 'foo3' is a violation of trusted computing base 'bar'}}
+    foo4(); // expected-warning {{calling 'foo4' is a violation of trusted computing base 'bar'}}
+    foo5(); // OK - in leaf node
+    foo6(); // OK - in multiple TCBs, one of which is the same
+    foo7(); // expected-warning {{calling 'foo7' is a violation of trusted computing base 'bar'}}
+    (void) __builtin_clz(5); // OK - builtins are excluded
+}
+
+// Normal use without any attributes works
+void foo3() {
+    foo9(); // no-warning
+}
+
+void foo5() {
+    // all calls should be okay, function in TCB leaf
+    foo2(); // no-warning
+    foo3(); // no-warning
+    foo4(); // no-warning
+}
+
+void foo6() {
+    foo1(); // expected-warning {{calling 'foo1' is a violation of trusted computing base 'bar2'}}
+    foo4(); // expected-warning {{calling 'foo4' is a violation of trusted computing base 'bar'}}
+    foo8(); // no-warning
+    foo7(); // #1
+    // expected-warning@#1 {{calling 'foo7' is a violation of trusted computing base 'bar2'}}
+    // expected-warning@#1 {{calling 'foo7' is a violation of trusted computing base 'bar'}}
+}
+
+// Ensure that attribute merging works as expected across redeclarations.
+void foo10() PLACE_IN_TCB("bar");
+void foo10() PLACE_IN_TCB("bar2");
+void foo10() PLACE_IN_TCB("bar3");
+void foo10() {
+  foo1(); // #2
+    // expected-warning@#2 {{calling 'foo1' is a violation of trusted computing base 'bar2'}}
+    // expected-warning@#2 {{calling 'foo1' is a violation of trusted computing base 'bar3'}}
+  foo3(); // #3
+    // expected-warning@#3 {{calling 'foo3' is a violation of trusted computing base 'bar'}}
+    // expected-warning@#3 {{calling 'foo3' is a violation of trusted computing base 'bar2'}}
+    // expected-warning@#3 {{calling 'foo3' is a violation of trusted computing base 'bar3'}}
+  foo4(); // #4
+    // expected-warning@#4 {{calling 'foo4' is a violation of trusted computing base 'bar'}}
+    // expected-warning@#4 {{calling 'foo4' is a violation of trusted computing base 'bar3'}}
+  foo7(); // #5
+    // expected-warning@#5 {{calling 'foo7' is a violation of trusted computing base 'bar'}}
+    // expected-warning@#5 {{calling 'foo7' is a violation of trusted computing base 'bar2'}}
+}