feat(xsnap): meter garbageCollectionCount

Author: dckc

packages/xsnap/api.js

@@ -3,7 +3,7 @@
 /** The version identifier for our meter type.
  * TODO Bump this whenever there's a change to metering semantics.
  */
-export const METER_TYPE = 'xs-meter-3';
+export const METER_TYPE = 'xs-meter-4';
 
 export const ExitCode = {
   E_UNKNOWN_ERROR: -1,

packages/xsnap/src/xsnap.c

@@ -1400,13 +1400,15 @@ static char* fxReadNetStringError(int code)
 
 static int fxWriteOkay(FILE* outStream, xsUnsignedValue meterIndex, txMachine *the, char* buf, size_t length)
 {
-	char fmt[] = ".{\"compute\":%u,\"allocate\":%u,\"allocateChunksCalls\":%u,\"allocateSlotsCalls\":%u}\1";
+	char fmt[] = ".{\"compute\":%u,\"allocate\":%u,\"allocateChunksCalls\":%u,\"allocateSlotsCalls\":%u,\"garbageCollectionCount\":%u}\1";
 	char numeral64[] = "12345678901234567890"; // big enough for 64bit numeral
 	char prefix[8 + sizeof fmt + 4 * sizeof numeral64];
 	// TODO: fxCollect counter
 	// Prepend the meter usage to the reply.
 	snprintf(prefix, sizeof(prefix) - 1, fmt,
-			 meterIndex, the->allocatedSpace, the->allocateChunksCallCount, the->allocateSlotsCallCount);
+			 meterIndex, the->allocatedSpace,
+			 the->allocateChunksCallCount, the->allocateSlotsCallCount,
+			 the->garbageCollectionCount);
 	return fxWriteNetString(outStream, prefix, buf, length);
 }
 

packages/xsnap/src/xsnap.h

@@ -71,6 +71,7 @@
 	txSize allocatedSpace; \
 	txUnsigned allocateChunksCallCount; \
 	txUnsigned allocateSlotsCallCount; \
+	txUnsigned garbageCollectionCount; \
 	int promiseJobs; \
 	void* timerJobs; \
 	void* waiterCondition; \

packages/xsnap/test/test-xsnap.js

@@ -521,14 +521,15 @@ test('meter details', async t => {
     meterUsage: { meterType, ...meters },
   } = result;
   t.log(meters);
-  t.is(meterType, 'xs-meter-3');
+  t.is(meterType, 'xs-meter-4');
   const { entries, fromEntries } = Object;
   t.deepEqual(
     {
       compute: 'number',
       allocate: 'number',
       allocateChunksCalls: 'number',
       allocateSlotsCalls: 'number',
+      garbageCollectionCount: 'number',
     },
     fromEntries(entries(meters).map(([p, v]) => [p, typeof v])),
   );