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Merge pull request #1142 from scottslacksmith/master

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Fix/silence false positive memory leaks reported by Microsoft's debug CRT
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Gennadiy Civil 2018-08-16 13:34:03 -04:00 committed by GitHub
commit 8b34930c62
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1 changed files with 44 additions and 2 deletions
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46
googletest/src/gtest-port.cc
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@ -294,6 +294,43 @@ void Mutex::AssertHeld() {
<< "The current thread is not holding the mutex @" << this;
}
namespace {
// Use the RAII idiom to flag mem allocs that are intentionally never
// deallocated. The motivation is to silence the false positive mem leaks
// that are reported by the debug version of MS's CRT which can only detect
// if an alloc is missing a matching deallocation.
// Example:
// MemoryIsNotDeallocated memory_is_not_deallocated;
// critical_section_ = new CRITICAL_SECTION;
//
class MemoryIsNotDeallocated
{
public:
MemoryIsNotDeallocated() : old_crtdbg_flag_(0) {
#ifdef _MSC_VER
old_crtdbg_flag_ = _CrtSetDbgFlag(_CRTDBG_REPORT_FLAG);
// Set heap allocation block type to _IGNORE_BLOCK so that MS debug CRT
// doesn't report mem leak if there's no matching deallocation.
_CrtSetDbgFlag(old_crtdbg_flag_ & ~_CRTDBG_ALLOC_MEM_DF);
#endif // _MSC_VER
}
~MemoryIsNotDeallocated() {
#ifdef _MSC_VER
// Restore the original _CRTDBG_ALLOC_MEM_DF flag
_CrtSetDbgFlag(old_crtdbg_flag_);
#endif // _MSC_VER
}
private:
int old_crtdbg_flag_;
GTEST_DISALLOW_COPY_AND_ASSIGN_(MemoryIsNotDeallocated);
};
} // namespace
// Initializes owner_thread_id_ and critical_section_ in static mutexes.
void Mutex::ThreadSafeLazyInit() {
// Dynamic mutexes are initialized in the constructor.
@ -304,7 +341,11 @@ void Mutex::ThreadSafeLazyInit() {
// If critical_section_init_phase_ was 0 before the exchange, we
// are the first to test it and need to perform the initialization.
owner_thread_id_ = 0;
critical_section_ = new CRITICAL_SECTION;
{
// Use RAII to flag that following mem alloc is never deallocated.
MemoryIsNotDeallocated memory_is_not_deallocated;
critical_section_ = new CRITICAL_SECTION;
}
::InitializeCriticalSection(critical_section_);
// Updates the critical_section_init_phase_ to 2 to signal
// initialization complete.
@ -546,7 +587,8 @@ class ThreadLocalRegistryImpl {
// Returns map of thread local instances.
static ThreadIdToThreadLocals* GetThreadLocalsMapLocked() {
mutex_.AssertHeld();
static ThreadIdToThreadLocals* map = new ThreadIdToThreadLocals;
MemoryIsNotDeallocated memory_is_not_deallocated;
static ThreadIdToThreadLocals* map = new ThreadIdToThreadLocals();
return map;
}