Tighten the safe points for code cache resets to happen.
Add a new flag in the Thread struct to track the whereabout of the top frame
in each Java thread. It is not safe to blow away the code cache if any thread
is in the JIT'ed land.
diff --git a/vm/compiler/codegen/arm/Assemble.c b/vm/compiler/codegen/arm/Assemble.c
index 7c16ff9..6a59c7e 100644
--- a/vm/compiler/codegen/arm/Assemble.c
+++ b/vm/compiler/codegen/arm/Assemble.c
@@ -1464,6 +1464,7 @@
/* Stop the world */
dvmSuspendAllThreads(SUSPEND_FOR_IC_PATCH);
+
COMPILER_TRACE_CHAINING(
LOGD("Jit Runtime: predicted chain %p from %s to %s (%s) patched",
cellDest, cellDest->clazz ? cellDest->clazz->descriptor : "NULL",
@@ -1542,11 +1543,14 @@
case kChainingCellInvokePredicted:
targetOffset = 0;
predChainCell = (PredictedChainingCell *) pChainCells;
- /* Reset the cell to the init state */
- predChainCell->branch = PREDICTED_CHAIN_BX_PAIR_INIT;
+ /*
+ * There could be a race on another mutator thread to use
+ * this particular predicted cell and the check has passed
+ * the clazz comparison. So we cannot safely wipe the
+ * method and branch but it is safe to clear the clazz,
+ * which serves as the key.
+ */
predChainCell->clazz = PREDICTED_CHAIN_CLAZZ_INIT;
- predChainCell->method = PREDICTED_CHAIN_METHOD_INIT;
- predChainCell->counter = PREDICTED_CHAIN_COUNTER_INIT;
break;
#if defined(WITH_SELF_VERIFICATION)
case kChainingCellBackwardBranch:
@@ -1611,6 +1615,7 @@
}
cacheflush((long)lowAddress, (long)highAddress, 0);
dvmUnlockMutex(&gDvmJit.tableLock);
+ gDvmJit.translationChains = 0;
}
}