Fix ExceptionPorts.TaskAndThreadExceptionPorts under better compiler optimization

util/mach/exception_ports_test.cc

Index: util/mach/exception_ports_test.cc
diff --git a/util/mach/exception_ports_test.cc b/util/mach/exception_ports_test.cc
index 43fb025757a32c706dc1abca830147d17938bb40..8948eae791668123ced9510c5a824d1f09d91a26 100644
--- a/util/mach/exception_ports_test.cc
+++ b/util/mach/exception_ports_test.cc
@@ -107,6 +107,12 @@ void TestGetExceptionPorts(const ExceptionPorts& exception_ports,
 class TestExceptionPorts : public MachMultiprocess,
                            public UniversalMachExcServer::Interface {
  public:
+  // Which entities to set exception ports for.
+  enum SetOn {
+    kSetOnTaskOnly = 0,
+    kSetOnTaskAndThreads,
+  };
+
   // Where to call ExceptionPorts::SetExceptionPort() from.
   enum SetType {
     // Call it from the child process on itself.
@@ -116,12 +122,6 @@ class TestExceptionPorts : public MachMultiprocess,
     kSetOutOfProcess,
   };
 
-  // Which entities to set exception ports for.
-  enum SetOn {
-    kSetOnTaskOnly = 0,
-    kSetOnTaskAndThreads,
-  };
-
   // Which thread in the child process is expected to crash.
   enum WhoCrashes {
     kNobodyCrashes = 0,
@@ -129,16 +129,16 @@ class TestExceptionPorts : public MachMultiprocess,
     kOtherThreadCrashes,
   };
 
-  TestExceptionPorts(SetType set_type, SetOn set_on, WhoCrashes who_crashes)
+  TestExceptionPorts(SetOn set_on, SetType set_type, WhoCrashes who_crashes)
       : MachMultiprocess(),
         UniversalMachExcServer::Interface(),
-        set_type_(set_type),
         set_on_(set_on),
+        set_type_(set_type),
         who_crashes_(who_crashes),
         handled_(false) {}
 
-  SetType set_type() const { return set_type_; }
   SetOn set_on() const { return set_on_; }
+  SetType set_type() const { return set_type_; }
   WhoCrashes who_crashes() const { return who_crashes_; }
 
   // UniversalMachExcServer::Interface:
@@ -191,10 +191,8 @@ class TestExceptionPorts : public MachMultiprocess,
       int signal;
       ExcCrashRecoverOriginalException(code[0], nullptr, &signal);
 
-      // The child crashed with a division by zero, which shows up as SIGFPE.
-      // This was chosen because it’s unlikely to be generated by testing or
-      // assertion failures.
-      EXPECT_EQ(SIGFPE, signal);
+      // The child crashed with __builtin_trap(), which shows up as SIGILL.
+      EXPECT_EQ(SIGILL, signal);
 
       SetExpectedChildTermination(kTerminationSignal, signal);
     }
@@ -326,10 +324,9 @@ class TestExceptionPorts : public MachMultiprocess,
       return nullptr;
     }
 
-    // Crashes by performing a division by zero. The assignment is present to
-    // avoid optimizing zero_ out entirely by making it appear that its value
-    // might change.
-    static void Crash() { zero_ = 1 / zero_; }
+    static void Crash() {
+      __builtin_trap();
+    }
 
     // The parent object.
     TestExceptionPorts* test_exception_ports_;  // weak
@@ -345,11 +342,6 @@ class TestExceptionPorts : public MachMultiprocess,
     // child can test its exception ports and possibly crash, as appropriate.
     Semaphore crash_semaphore_;
 
-    // Always zero. Crash() divides by this in order to trigger a crash. This is
-    // structured as a static volatile int to ward off aggressive compiler
-    // optimizations.
-    static volatile int zero_;
-
     DISALLOW_COPY_AND_ASSIGN(Child);
   };
 
@@ -447,13 +439,14 @@ class TestExceptionPorts : public MachMultiprocess,
     if (who_crashes_ != kNobodyCrashes) {
       UniversalMachExcServer universal_mach_exc_server(this);
 
+      const mach_msg_timeout_t kTimeoutMs = 50;
       kern_return_t kr =
           MachMessageServer::Run(&universal_mach_exc_server,
                                  local_port,
                                  MACH_MSG_OPTION_NONE,
                                  MachMessageServer::kOneShot,
                                  MachMessageServer::kReceiveLargeError,
-                                 kMachMessageTimeoutWaitIndefinitely);
+                                 kTimeoutMs);
       EXPECT_EQ(KERN_SUCCESS, kr)
           << MachErrorMessage(kr, "MachMessageServer::Run");
 
@@ -471,8 +464,8 @@ class TestExceptionPorts : public MachMultiprocess,
     child.Run();
   }
 
-  SetType set_type_;
   SetOn set_on_;
+  SetType set_type_;
   WhoCrashes who_crashes_;
 
   // true if an exception message was handled.
@@ -481,66 +474,103 @@ class TestExceptionPorts : public MachMultiprocess,
   DISALLOW_COPY_AND_ASSIGN(TestExceptionPorts);
 };
 
-volatile int TestExceptionPorts::Child::zero_ = 0;
+TEST(ExceptionPorts, TaskExceptionPorts_SetInProcess_NoCrash) {
+  TestExceptionPorts test_exception_ports(
+      TestExceptionPorts::kSetOnTaskOnly,
+      TestExceptionPorts::kSetInProcess,
+      TestExceptionPorts::kNobodyCrashes);
+  test_exception_ports.Run();
+}
 
-TEST(ExceptionPorts, TaskAndThreadExceptionPorts) {
-  struct Testcase {
-    TestExceptionPorts::SetType set_type;
-    TestExceptionPorts::SetOn set_on;
-    TestExceptionPorts::WhoCrashes who_crashes;
-  };
-  const Testcase kTestcases[] = {
-      {TestExceptionPorts::kSetInProcess,
-       TestExceptionPorts::kSetOnTaskOnly,
-       TestExceptionPorts::kNobodyCrashes},
-      {TestExceptionPorts::kSetInProcess,
-       TestExceptionPorts::kSetOnTaskOnly,
-       TestExceptionPorts::kMainThreadCrashes},
-      {TestExceptionPorts::kSetInProcess,
-       TestExceptionPorts::kSetOnTaskOnly,
-       TestExceptionPorts::kOtherThreadCrashes},
-      {TestExceptionPorts::kSetInProcess,
-       TestExceptionPorts::kSetOnTaskAndThreads,
-       TestExceptionPorts::kNobodyCrashes},
-      {TestExceptionPorts::kSetInProcess,
-       TestExceptionPorts::kSetOnTaskAndThreads,
-       TestExceptionPorts::kMainThreadCrashes},
-      {TestExceptionPorts::kSetInProcess,
-       TestExceptionPorts::kSetOnTaskAndThreads,
-       TestExceptionPorts::kOtherThreadCrashes},
-      {TestExceptionPorts::kSetOutOfProcess,
-       TestExceptionPorts::kSetOnTaskOnly,
-       TestExceptionPorts::kNobodyCrashes},
-      {TestExceptionPorts::kSetOutOfProcess,
-       TestExceptionPorts::kSetOnTaskOnly,
-       TestExceptionPorts::kMainThreadCrashes},
-      {TestExceptionPorts::kSetOutOfProcess,
-       TestExceptionPorts::kSetOnTaskOnly,
-       TestExceptionPorts::kOtherThreadCrashes},
-      {TestExceptionPorts::kSetOutOfProcess,
-       TestExceptionPorts::kSetOnTaskAndThreads,
-       TestExceptionPorts::kNobodyCrashes},
-      {TestExceptionPorts::kSetOutOfProcess,
-       TestExceptionPorts::kSetOnTaskAndThreads,
-       TestExceptionPorts::kMainThreadCrashes},
-      {TestExceptionPorts::kSetOutOfProcess,
-       TestExceptionPorts::kSetOnTaskAndThreads,
-       TestExceptionPorts::kOtherThreadCrashes},
-  };
+TEST(ExceptionPorts, TaskExceptionPorts_SetInProcess_MainThreadCrash) {
+  TestExceptionPorts test_exception_ports(
+      TestExceptionPorts::kSetOnTaskOnly,
+      TestExceptionPorts::kSetInProcess,
+      TestExceptionPorts::kMainThreadCrashes);
+  test_exception_ports.Run();
+}
 
-  for (size_t index = 0; index < arraysize(kTestcases); ++index) {
-    const Testcase& testcase = kTestcases[index];
-    SCOPED_TRACE(
-        base::StringPrintf("index %zu, set_type %d, set_on %d, who_crashes %d",
-                           index,
-                           testcase.set_type,
-                           testcase.set_on,
-                           testcase.who_crashes));
-
-    TestExceptionPorts test_exception_ports(
-        testcase.set_type, testcase.set_on, testcase.who_crashes);
-    test_exception_ports.Run();
-  }
+TEST(ExceptionPorts, TaskExceptionPorts_SetInProcess_OtherThreadCrash) {
+  TestExceptionPorts test_exception_ports(
+      TestExceptionPorts::kSetOnTaskOnly,
+      TestExceptionPorts::kSetInProcess,
+      TestExceptionPorts::kOtherThreadCrashes);
+  test_exception_ports.Run();
+}
+
+TEST(ExceptionPorts, TaskAndThreadExceptionPorts_SetInProcess_NoCrash) {
+  TestExceptionPorts test_exception_ports(
+      TestExceptionPorts::kSetOnTaskAndThreads,
+      TestExceptionPorts::kSetInProcess,
+      TestExceptionPorts::kNobodyCrashes);
+  test_exception_ports.Run();
+}
+
+TEST(ExceptionPorts, TaskAndThreadExceptionPorts_SetInProcess_MainThreadCrash) {
+  TestExceptionPorts test_exception_ports(
+      TestExceptionPorts::kSetOnTaskAndThreads,
+      TestExceptionPorts::kSetInProcess,
+      TestExceptionPorts::kMainThreadCrashes);
+  test_exception_ports.Run();
+}
+
+TEST(ExceptionPorts,
+     TaskAndThreadExceptionPorts_SetInProcess_OtherThreadCrash) {
+  TestExceptionPorts test_exception_ports(
+      TestExceptionPorts::kSetOnTaskAndThreads,
+      TestExceptionPorts::kSetInProcess,
+      TestExceptionPorts::kOtherThreadCrashes);
+  test_exception_ports.Run();
+}
+
+TEST(ExceptionPorts, TaskExceptionPorts_SetOutOfProcess_NoCrash) {
+  TestExceptionPorts test_exception_ports(
+      TestExceptionPorts::kSetOnTaskOnly,
+      TestExceptionPorts::kSetOutOfProcess,
+      TestExceptionPorts::kNobodyCrashes);
+  test_exception_ports.Run();
+}
+
+TEST(ExceptionPorts, TaskExceptionPorts_SetOutOfProcess_MainThreadCrash) {
+  TestExceptionPorts test_exception_ports(
+      TestExceptionPorts::kSetOnTaskOnly,
+      TestExceptionPorts::kSetOutOfProcess,
+      TestExceptionPorts::kMainThreadCrashes);
+  test_exception_ports.Run();
+}
+
+TEST(ExceptionPorts, TaskExceptionPorts_SetOutOfProcess_OtherThreadCrash) {
+  TestExceptionPorts test_exception_ports(
+      TestExceptionPorts::kSetOnTaskOnly,
+      TestExceptionPorts::kSetOutOfProcess,
+      TestExceptionPorts::kOtherThreadCrashes);
+  test_exception_ports.Run();
+}
+
+TEST(ExceptionPorts, TaskAndThreadExceptionPorts_SetOutOfProcess_NoCrash) {
+  TestExceptionPorts test_exception_ports(
+      TestExceptionPorts::kSetOnTaskAndThreads,
+      TestExceptionPorts::kSetOutOfProcess,
+      TestExceptionPorts::kNobodyCrashes);
+  test_exception_ports.Run();
+}
+
+TEST(ExceptionPorts,
+     TaskAndThreadExceptionPorts_SetOutOfProcess_MainThreadCrash) {
+  TestExceptionPorts test_exception_ports(
+      TestExceptionPorts::kSetOnTaskAndThreads,
+      TestExceptionPorts::kSetOutOfProcess,
+      TestExceptionPorts::kMainThreadCrashes);
+  test_exception_ports.Run();
+}
+
+TEST(ExceptionPorts,
+     TaskAndThreadExceptionPorts_SetOutOfProcess_OtherThreadCrash) {
+  TestExceptionPorts test_exception_ports(
+      TestExceptionPorts::kSetOnTaskAndThreads,
+      TestExceptionPorts::kSetOutOfProcess,
+      TestExceptionPorts::kOtherThreadCrashes);
+  test_exception_ports.Run();
 }
 
 TEST(ExceptionPorts, HostExceptionPorts) {