1 files changed, 197 insertions, 0 deletions
diff --git a/test/SemaCXX/switch-implicit-fallthrough.cpp b/test/SemaCXX/switch-implicit-fallthrough.cpp
new file mode 100644
index 000000000000..cfc29c237c2d
--- /dev/null
+++ b/test/SemaCXX/switch-implicit-fallthrough.cpp
@@ -0,0 +1,197 @@
+// RUN: %clang_cc1 -fsyntax-only -verify -std=c++11 -Wimplicit-fallthrough %s
+
+
+int fallthrough(int n) {
+  switch (n / 10) {
+      if (n - 1) {
+        n = 100;
+      } else if (n - 2) {
+        n = 101;
+      } else if (n - 3) {
+        n = 102;
+      }
+    case -1: // expected-warning{{unannotated fall-through between switch labels}} expected-note{{insert '[[clang::fallthrough]];' to silence this warning}} expected-note{{insert 'break;' to avoid fall-through}}
+      ;
+    case 0: {// expected-warning{{unannotated fall-through between switch labels}} expected-note{{insert '[[clang::fallthrough]];' to silence this warning}} expected-note{{insert 'break;' to avoid fall-through}}
+    }
+    case 1:  // expected-warning{{unannotated fall-through between switch labels}} expected-note{{insert '[[clang::fallthrough]];' to silence this warning}} expected-note{{insert 'break;' to avoid fall-through}}
+      n += 100         ;
+    case 3:  // expected-warning{{unannotated fall-through between switch labels}} expected-note{{insert '[[clang::fallthrough]];' to silence this warning}} expected-note{{insert 'break;' to avoid fall-through}}
+      if (n > 0)
+        n += 200;
+    case 4:  // expected-warning{{unannotated fall-through between switch labels}} expected-note{{insert '[[clang::fallthrough]];' to silence this warning}} expected-note{{insert 'break;' to avoid fall-through}}
+      if (n < 0)
+        ;
+    case 5:  // expected-warning{{unannotated fall-through between switch labels}} expected-note{{insert '[[clang::fallthrough]];' to silence this warning}} expected-note{{insert 'break;' to avoid fall-through}}
+      switch (n) {
+      case 111:
+        break;
+      case 112:
+        break;
+      case 113:
+        break    ;
+      }
+    case 6:  // expected-warning{{unannotated fall-through between switch labels}} expected-note{{insert '[[clang::fallthrough]];' to silence this warning}} expected-note{{insert 'break;' to avoid fall-through}}
+      n += 300;
+    case 66:  // expected-warning{{unannotated fall-through between switch labels}} expected-note{{insert 'break;' to avoid fall-through}}
+      break;
+  }
+  switch (n / 20) {
+    case 7:
+      n += 400;
+      [[clang::fallthrough]];
+    case 9:  // no warning here, intended fall-through marked with an attribute
+      n += 800;
+      [[clang::fallthrough]];
+    default: { // no warning here, intended fall-through marked with an attribute
+      if (n % 2 == 0) {
+        return 1;
+      } else {
+        [[clang::fallthrough]];
+      }
+    }
+    case 10:  // no warning here, intended fall-through marked with an attribute
+      if (n % 3 == 0) {
+        n %= 3;
+      } else {
+        [[clang::fallthrough]];
+      }
+    case 110:  // expected-warning{{unannotated fall-through between switch labels}} but no fix-it hint as we have one fall-through annotation!
+      n += 800;
+  }
+  switch (n / 30) {
+    case 11:
+    case 12:  // no warning here, intended fall-through, no statement between labels
+      n += 1600;
+  }
+  switch (n / 40) {
+    case 13:
+      if (n % 2 == 0) {
+        return 1;
+      } else {
+        return 2;
+      }
+    case 15:  // no warning here, there's no fall-through
+      n += 3200;
+  }
+  switch (n / 50) {
+    case 17: {
+      if (n % 2 == 0) {
+        return 1;
+      } else {
+        return 2;
+      }
+    }
+    case 19: { // no warning here, there's no fall-through
+      n += 6400;
+      return 3;
+    }
+    case 21: { // no warning here, there's no fall-through
+      break;
+    }
+    case 23: // no warning here, there's no fall-through
+      n += 128000;
+      break;
+    case 25: // no warning here, there's no fall-through
+      break;
+  }
+
+  return n;
+}
+
+class ClassWithDtor {
+public:
+  ~ClassWithDtor() {}
+};
+
+void fallthrough2(int n) {
+  switch (n) {
+    case 0:
+    {
+      ClassWithDtor temp;
+      break;
+    }
+    default: // no warning here, there's no fall-through
+      break;
+  }
+}
+
+#define MY_SWITCH(X, Y, Z, U, V) switch (X) { case Y: Z; case U: V; }
+#define MY_SWITCH2(X, Y, Z) switch (X) { Y; Z; }
+#define MY_CASE(X, Y) case X: Y
+#define MY_CASE2(X, Y, U, V) case X: Y; case U: V
+
+int fallthrough_macro1(int n) {
+  MY_SWITCH(n, 13, n *= 2, 14, break)  // expected-warning{{unannotated fall-through between switch labels}}
+
+  switch (n + 1) {
+    MY_CASE(33, n += 2);
+    MY_CASE(44, break);  // expected-warning{{unannotated fall-through between switch labels}}
+    MY_CASE(55, n += 3);
+  }
+
+  switch (n + 3) {
+    MY_CASE(333, return 333);
+    MY_CASE2(444, n += 44, 4444, break);  // expected-warning{{unannotated fall-through between switch labels}}
+    MY_CASE(555, n += 33);
+  }
+
+  MY_SWITCH2(n + 4, MY_CASE(17, n *= 3), MY_CASE(19, break))  // expected-warning{{unannotated fall-through between switch labels}}
+
+  MY_SWITCH2(n + 5, MY_CASE(21, break), MY_CASE2(23, n *= 7, 25, break))  // expected-warning{{unannotated fall-through between switch labels}}
+
+  return n;
+}
+
+int fallthrough_position(int n) {
+  switch (n) {
+      [[clang::fallthrough]];  // expected-warning{{fallthrough annotation in unreachable code}}
+    case 221:
+      [[clang::fallthrough]]; // expected-warning{{fallthrough annotation does not directly precede switch label}}
+      return 1;
+      [[clang::fallthrough]];  // expected-warning{{fallthrough annotation in unreachable code}}
+    case 222:
+      [[clang::fallthrough]]; // expected-warning{{fallthrough annotation does not directly precede switch label}}
+      n += 400;
+    case 223:          // expected-warning{{unannotated fall-through between switch labels}} expected-note{{insert '[[clang::fallthrough]];' to silence this warning}} expected-note{{insert 'break;' to avoid fall-through}}
+      [[clang::fallthrough]]; // expected-warning{{fallthrough annotation does not directly precede switch label}}
+  }
+
+  // TODO: uncomment this test after CFG gets more options to deal with
+  // unreachable code:
+  // http://lists.cs.uiuc.edu/pipermail/cfe-commits/Week-of-Mon-20120507/057370.html
+#if 0
+  long p = static_cast<long>(n) * n;
+  switch (sizeof(p)) {
+    case 9:                    // this test will not work on compilers with 72-bit long
+      n += static_cast<int>(p >> 32);
+      [[clang::fallthrough]];  // no warning here
+    case 5:                    // it is not intended to work on compilers with 40-bit long as well
+      n += static_cast<int>(p);
+      break;
+    default:
+     break;
+  }
+#endif
+
+  return n;
+}
+
+int fallthrough_targets(int n) {
+  [[clang::fallthrough]]; // expected-error{{fallthrough annotation is outside switch statement}}
+
+  [[clang::fallthrough]]  // expected-error{{fallthrough attribute is only allowed on empty statements}}
+  switch (n) {
+    case 121:
+      n += 400;
+      [[clang::fallthrough]]; // no warning here, correct target
+    case 123:
+      [[clang::fallthrough]]  // expected-error{{fallthrough attribute is only allowed on empty statements}}
+      n += 800;
+      break;
+    [[clang::fallthrough]]    // expected-error{{fallthrough attribute is only allowed on empty statements}} expected-note{{did you forget ';'?}}
+    case 125:
+      n += 1600;
+  }
+  return n;
+}