Merge "Add heuristic data race detection to sp<>" am: 04abdc6153 am: 12d6afe6f1
am: 764d347183
Change-Id: I6a27520e80c2adefe30b0d04ce7e470188d3ad99
diff --git a/libutils/Android.bp b/libutils/Android.bp
index b772b78..9c300e0 100644
--- a/libutils/Android.bp
+++ b/libutils/Android.bp
@@ -44,6 +44,7 @@
"StopWatch.cpp",
"String8.cpp",
"String16.cpp",
+ "StrongPointer.cpp",
"SystemClock.cpp",
"Threads.cpp",
"Timers.cpp",
diff --git a/libutils/StrongPointer.cpp b/libutils/StrongPointer.cpp
new file mode 100644
index 0000000..ba52502
--- /dev/null
+++ b/libutils/StrongPointer.cpp
@@ -0,0 +1,24 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define LOG_TAG "sp"
+
+#include <log/log.h>
+
+namespace android {
+
+void sp_report_race() { LOG_ALWAYS_FATAL("sp<> assignment detected data race"); }
+}
diff --git a/libutils/include/utils/StrongPointer.h b/libutils/include/utils/StrongPointer.h
index cdfdd8a..0c20607 100644
--- a/libutils/include/utils/StrongPointer.h
+++ b/libutils/include/utils/StrongPointer.h
@@ -102,6 +102,9 @@
T* m_ptr;
};
+// For code size reasons, we do not want this inlined or templated.
+void sp_report_race();
+
#undef COMPARE
// ---------------------------------------------------------------------------
@@ -155,19 +158,21 @@
template<typename T>
sp<T>& sp<T>::operator =(const sp<T>& other) {
+ // Force m_ptr to be read twice, to heuristically check for data races.
+ T* oldPtr(*const_cast<T* volatile*>(&m_ptr));
T* otherPtr(other.m_ptr);
- if (otherPtr)
- otherPtr->incStrong(this);
- if (m_ptr)
- m_ptr->decStrong(this);
+ if (otherPtr) otherPtr->incStrong(this);
+ if (oldPtr) oldPtr->decStrong(this);
+ if (oldPtr != *const_cast<T* volatile*>(&m_ptr)) sp_report_race();
m_ptr = otherPtr;
return *this;
}
template<typename T>
sp<T>& sp<T>::operator =(sp<T>&& other) {
- if (m_ptr)
- m_ptr->decStrong(this);
+ T* oldPtr(*const_cast<T* volatile*>(&m_ptr));
+ if (oldPtr) oldPtr->decStrong(this);
+ if (oldPtr != *const_cast<T* volatile*>(&m_ptr)) sp_report_race();
m_ptr = other.m_ptr;
other.m_ptr = nullptr;
return *this;
@@ -175,29 +180,30 @@
template<typename T>
sp<T>& sp<T>::operator =(T* other) {
- if (other)
- other->incStrong(this);
- if (m_ptr)
- m_ptr->decStrong(this);
+ T* oldPtr(*const_cast<T* volatile*>(&m_ptr));
+ if (other) other->incStrong(this);
+ if (oldPtr) oldPtr->decStrong(this);
+ if (oldPtr != *const_cast<T* volatile*>(&m_ptr)) sp_report_race();
m_ptr = other;
return *this;
}
template<typename T> template<typename U>
sp<T>& sp<T>::operator =(const sp<U>& other) {
+ T* oldPtr(*const_cast<T* volatile*>(&m_ptr));
T* otherPtr(other.m_ptr);
- if (otherPtr)
- otherPtr->incStrong(this);
- if (m_ptr)
- m_ptr->decStrong(this);
+ if (otherPtr) otherPtr->incStrong(this);
+ if (oldPtr) oldPtr->decStrong(this);
+ if (oldPtr != *const_cast<T* volatile*>(&m_ptr)) sp_report_race();
m_ptr = otherPtr;
return *this;
}
template<typename T> template<typename U>
sp<T>& sp<T>::operator =(sp<U>&& other) {
- if (m_ptr)
- m_ptr->decStrong(this);
+ T* oldPtr(*const_cast<T* volatile*>(&m_ptr));
+ if (m_ptr) m_ptr->decStrong(this);
+ if (oldPtr != *const_cast<T* volatile*>(&m_ptr)) sp_report_race();
m_ptr = other.m_ptr;
other.m_ptr = nullptr;
return *this;
@@ -205,10 +211,10 @@
template<typename T> template<typename U>
sp<T>& sp<T>::operator =(U* other) {
- if (other)
- (static_cast<T*>(other))->incStrong(this);
- if (m_ptr)
- m_ptr->decStrong(this);
+ T* oldPtr(*const_cast<T* volatile*>(&m_ptr));
+ if (other) (static_cast<T*>(other))->incStrong(this);
+ if (oldPtr) oldPtr->decStrong(this);
+ if (oldPtr != *const_cast<T* volatile*>(&m_ptr)) sp_report_race();
m_ptr = other;
return *this;
}