Extend vmState to pre/post collect

Current vmState for Collector does not include pre- and post- collect.
If crash occur in pre- or post- collect vmState can be misleading.

Signed-off-by: Dmitri Pivkine <[email protected]>

gc/base/Collector.cpp

@@ -489,23 +489,21 @@ MM_Collector::garbageCollect(MM_EnvironmentBase* env, MM_MemorySubSpace* calling
 {
 	Assert_MM_mustHaveExclusiveVMAccess(env->getOmrVMThread());
 
+	uintptr_t vmState = env->pushVMstate(getVMStateID());
+
 	Assert_MM_true(NULL == env->_cycleState);
 	preCollect(env, callingSubSpace, allocateDescription, gcCode);
 	Assert_MM_true(NULL != env->_cycleState);
 
 	/* ensure that we aren't trying to collect while in a NoGC allocation */
 	Assert_MM_false(env->_isInNoGCAllocationCall);
 
-	uintptr_t vmState = env->pushVMstate(getVMStateID());
-
 	/* First do any pre-collection initialization of the collector*/
 	setupForGC(env);
 
 	/* perform the collection */
 	_gcCompleted = internalGarbageCollect(env, callingSubSpace, allocateDescription);
 
-	env->popVMstate(vmState);
-
 	/* now, see if we need to resume an allocation or replenishment attempt */
 	void* postCollectAllocationResult = NULL;
 	if (NULL != allocateDescription) {
@@ -527,6 +525,8 @@ MM_Collector::garbageCollect(MM_EnvironmentBase* env, MM_MemorySubSpace* calling
 	Assert_MM_true(NULL != env->_cycleState);
 	env->_cycleState = NULL;
 
+	env->popVMstate(vmState);
+
 	return postCollectAllocationResult;
 }