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authorivanpe@chromium.org <ivanpe@chromium.org@4c0a9323-5329-0410-9bdc-e9ce6186880e>2014-07-01 17:50:05 +0000
committerivanpe@chromium.org <ivanpe@chromium.org@4c0a9323-5329-0410-9bdc-e9ce6186880e>2014-07-01 17:50:05 +0000
commitbf0e00374f06791e5d35c98a2b31b57774ffe5f6 (patch)
treec7f263e31ac8b9f2022127034c842c37f64fd88d /src/client/linux/handler
parentdump_syms: use unordered_set<> instead of set<> for speed. (diff)
downloadbreakpad-bf0e00374f06791e5d35c98a2b31b57774ffe5f6.tar.xz
Cleanup: hide undefined behavior from the compiler better.
Submitting this on behalf of Paul Pluzhnikov. R=mark@chromium.org Review URL: https://breakpad.appspot.com/6674002 git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1342 4c0a9323-5329-0410-9bdc-e9ce6186880e
Diffstat (limited to 'src/client/linux/handler')
-rw-r--r--src/client/linux/handler/exception_handler_unittest.cc22
1 files changed, 18 insertions, 4 deletions
diff --git a/src/client/linux/handler/exception_handler_unittest.cc b/src/client/linux/handler/exception_handler_unittest.cc
index 976f9f41..fc81f61f 100644
--- a/src/client/linux/handler/exception_handler_unittest.cc
+++ b/src/client/linux/handler/exception_handler_unittest.cc
@@ -193,6 +193,20 @@ static bool DoneCallback(const MinidumpDescriptor& descriptor,
#ifndef ADDRESS_SANITIZER
+// This is a replacement for "*reinterpret_cast<volatile int*>(NULL) = 0;"
+// It is needed because GCC is allowed to assume that the program will
+// not execute any undefined behavior (UB) operation. Further, when GCC
+// observes that UB statement is reached, it can assume that all statements
+// leading to the UB one are never executed either, and can completely
+// optimize them out. In the case of ExceptionHandlerTest::ExternalDumper,
+// GCC-4.9 optimized out the entire set up of ExceptionHandler, causing
+// test failure.
+volatile int *p_null; // external linkage, so GCC can't tell that it
+ // remains NULL. Volatile just for a good measure.
+static void DoNullPointerDereference() {
+ *p_null = 1;
+}
+
void ChildCrash(bool use_fd) {
AutoTempDir temp_dir;
int fds[2] = {0};
@@ -219,7 +233,7 @@ void ChildCrash(bool use_fd) {
true, -1));
}
// Crash with the exception handler in scope.
- *reinterpret_cast<volatile int*>(NULL) = 0;
+ DoNullPointerDereference();
}
}
if (!use_fd)
@@ -295,7 +309,7 @@ static void CrashWithCallbacks(ExceptionHandler::FilterCallback filter,
ExceptionHandler handler(
MinidumpDescriptor(path), filter, done, NULL, true, -1);
// Crash with the exception handler in scope.
- *reinterpret_cast<volatile int*>(NULL) = 0;
+ DoNullPointerDereference();
}
TEST(ExceptionHandlerTest, RedeliveryOnFilterCallbackFalse) {
@@ -386,7 +400,7 @@ TEST(ExceptionHandlerTest, RedeliveryOnBadSignalHandlerFlag) {
reinterpret_cast<void*>(SIG_ERR));
// Crash with the exception handler in scope.
- *reinterpret_cast<volatile int*>(NULL) = 0;
+ DoNullPointerDereference();
}
// SIGKILL means Breakpad's signal handler didn't crash.
ASSERT_NO_FATAL_FAILURE(WaitForProcessToTerminate(child, SIGKILL));
@@ -922,7 +936,7 @@ TEST(ExceptionHandlerTest, ExternalDumper) {
ExceptionHandler handler(MinidumpDescriptor("/tmp1"), NULL, NULL,
reinterpret_cast<void*>(fds[1]), true, -1);
handler.set_crash_handler(CrashHandler);
- *reinterpret_cast<volatile int*>(NULL) = 0;
+ DoNullPointerDereference();
}
close(fds[1]);
struct msghdr msg = {0};