C++: Add tests to demonstrate that it's not barrier guard that's buggy. Rather, it's the GuardCondition library.

cpp/ql/test/library-tests/dataflow/dataflow-tests/BarrierGuard.cpp

@@ -83,5 +83,46 @@ void test_guard_and_reassign() {
   if(!guarded(x)) {
     x = 0;
   }
+  sink(x); // $ SPURIOUS: ast,ir
+}
+
+void test_phi_read_guard(bool b) {
+  int x = source();
+
+  if(b) {
+    if(!guarded(x))
+      return;
+  }
+  else {
+    if(!guarded(x))
+      return;
+  }
+  
+  sink(x); // $ SPURIOUS: ast,ir
+}
+
+bool unsafe(int);
+
+void test_guard_and_reassign_2() {
+  int x = source();
+
+  if(unsafe(x)) {
+    x = 0;
+  }
   sink(x); // $ SPURIOUS: ast
 }
+
+void test_phi_read_guard_2(bool b) {
+  int x = source();
+
+  if(b) {
+    if(unsafe(x))
+      return;
+  }
+  else {
+    if(unsafe(x))
+      return;
+  }
+  
+  sink(x); // $ SPURIOUS: ast
+}

cpp/ql/test/library-tests/dataflow/dataflow-tests/TestBase.qll

@@ -11,6 +11,10 @@ module AstTest {
     g.(FunctionCall).getTarget().getName() = "guarded" and
     checked = g.(FunctionCall).getArgument(0) and
     isTrue = true
+    or
+    g.(FunctionCall).getTarget().getName() = "unsafe" and
+    checked = g.(FunctionCall).getArgument(0) and
+    isTrue = false
   }
 
   /** Common data flow configuration to be used by tests. */
@@ -105,9 +109,13 @@ module IRTest {
   predicate testBarrierGuard(IRGuardCondition g, Expr checked, boolean isTrue) {
     exists(Call call |
       call = g.getUnconvertedResultExpression() and
+      checked = call.getArgument(0)
+    |
       call.getTarget().hasName("guarded") and
-      checked = call.getArgument(0) and
       isTrue = true
+      or
+      call.getTarget().hasName("unsafe") and
+      isTrue = false
     )
   }
 

cpp/ql/test/library-tests/dataflow/dataflow-tests/test-source-sink.expected

@@ -13,6 +13,9 @@ astFlow
 | BarrierGuard.cpp:60:11:60:16 | call to source | BarrierGuard.cpp:64:14:64:14 | x |
 | BarrierGuard.cpp:60:11:60:16 | call to source | BarrierGuard.cpp:66:14:66:14 | x |
 | BarrierGuard.cpp:81:11:81:16 | call to source | BarrierGuard.cpp:86:8:86:8 | x |
+| BarrierGuard.cpp:90:11:90:16 | call to source | BarrierGuard.cpp:101:8:101:8 | x |
+| BarrierGuard.cpp:107:11:107:16 | call to source | BarrierGuard.cpp:112:8:112:8 | x |
+| BarrierGuard.cpp:116:11:116:16 | call to source | BarrierGuard.cpp:127:8:127:8 | x |
 | acrossLinkTargets.cpp:19:27:19:32 | call to source | acrossLinkTargets.cpp:12:8:12:8 | x |
 | clang.cpp:12:9:12:20 | sourceArray1 | clang.cpp:18:8:18:19 | sourceArray1 |
 | clang.cpp:12:9:12:20 | sourceArray1 | clang.cpp:22:8:22:20 | & ... |
@@ -142,6 +145,8 @@ irFlow
 | BarrierGuard.cpp:49:10:49:15 | call to source | BarrierGuard.cpp:55:13:55:13 | x |
 | BarrierGuard.cpp:60:11:60:16 | call to source | BarrierGuard.cpp:64:14:64:14 | x |
 | BarrierGuard.cpp:60:11:60:16 | call to source | BarrierGuard.cpp:66:14:66:14 | x |
+| BarrierGuard.cpp:81:11:81:16 | call to source | BarrierGuard.cpp:86:8:86:8 | x |
+| BarrierGuard.cpp:90:11:90:16 | call to source | BarrierGuard.cpp:101:8:101:8 | x |
 | acrossLinkTargets.cpp:19:27:19:32 | call to source | acrossLinkTargets.cpp:12:8:12:8 | x |
 | clang.cpp:12:9:12:20 | sourceArray1 | clang.cpp:18:8:18:19 | sourceArray1 |
 | clang.cpp:12:9:12:20 | sourceArray1 | clang.cpp:23:17:23:29 | *& ... |