Runtime compressed refs work

Add instance APIs to adjust the slot address in SlotObject. Signed-off-by: Graham Chapman <[email protected]>
jonoommen · May 19, 2020 · 1da61d8 · 1da61d8
1 parent 56abd35
commit 1da61d8
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Showing 2 changed files with 26 additions and 5 deletions.
diff --git a/gc/base/SlotObject.hpp b/gc/base/SlotObject.hpp
@@ -224,6 +224,26 @@ class GC_SlotObject
 		_slot = slot;
 	}
 
+	/**
+	 * Advance the slot address by an integer offset
+	 *
+	 * @param[in] offset the offset to add
+	 */
+	MMINLINE void addToSlotAddress(intptr_t offset)
+	{
+		writeAddressToSlot(addToSlotAddress(readAddressFromSlot(), offset, compressObjectReferences()));
+	}
+
+	/**
+	 * Back up the slot address by an integer offset
+	 *
+	 * @param[in] offset the offset to subtract
+	 */
+	MMINLINE void subtractFromSlotAddress(intptr_t offset)
+	{
+		writeAddressToSlot(subtractFromSlotAddress(readAddressFromSlot(), offset, compressObjectReferences()));
+	}
+
 	GC_SlotObject(OMR_VM *omrVM, volatile fomrobject_t* slot)
 	: _slot(slot)
 #if defined (OMR_GC_COMPRESSED_POINTERS)

diff --git a/gc/base/segregated/MemoryPoolSegregated.cpp b/gc/base/segregated/MemoryPoolSegregated.cpp
@@ -139,7 +139,7 @@ MM_MemoryPoolSegregated::allocateChunkedArray(MM_EnvironmentBase *env, MM_Alloca
 		fomrobject_t *arrayoidPtr = _extensions->indexableObjectModel.getArrayoidPointer(spine);
 		Assert_MM_true(totalBytes >= spineBytes);
 		uintptr_t bytesRemaining = totalBytes - spineBytes;
-		bool const compressed = compressObjectReferences();
+		GC_SlotObject arrayletSlotObject(env->getOmrVM(), arrayoidPtr);
 		for (uintptr_t i=0; i<numberArraylets; i++) {
 			uintptr_t* arraylet = NULL;
 			if (0 < bytesRemaining) {
@@ -148,16 +148,17 @@ MM_MemoryPoolSegregated::allocateChunkedArray(MM_EnvironmentBase *env, MM_Alloca
 					/* allocation failed; release all storage include spine. */
 					env->getAllocationContext()->flush(env);
 
+					GC_SlotObject backoutSlotObject(env->getOmrVM(), arrayoidPtr);
 					for (uintptr_t j=0; j<i; j++) {
-						GC_SlotObject slotObject(env->getOmrVM(), GC_SlotObject::addToSlotAddress(arrayoidPtr, j, compressed));
-						arraylet = (uintptr_t*)slotObject.readReferenceFromSlot();
+						arraylet = (uintptr_t*)backoutSlotObject.readReferenceFromSlot();
 
 						MM_HeapRegionDescriptorSegregated *region = (MM_HeapRegionDescriptorSegregated *)regionManager->tableDescriptorForAddress(arraylet);
 						region->clearArraylet(region->whichArraylet(arraylet, arrayletLeafLogSize));
 						/* Arraylet backout means arraylets may be re-used before the next cycle, so we need to correct for 
 						 * their un-allocation
 						 */
 						region->addBytesFreedToArrayletBackout(env);
+						backoutSlotObject.addToSlotAddress(1);
 					}
 					MM_HeapRegionDescriptorSegregated *region = (MM_HeapRegionDescriptorSegregated *)regionManager->tableDescriptorForAddress((uintptr_t *)spine);
 					if (region->isSmall()) {
@@ -181,8 +182,8 @@ MM_MemoryPoolSegregated::allocateChunkedArray(MM_EnvironmentBase *env, MM_Alloca
 				 */
 				Assert_MM_true(i == numberArraylets - 1);
 			}
-			GC_SlotObject slotObject(env->getOmrVM(), GC_SlotObject::addToSlotAddress(arrayoidPtr, i, compressed));
-			slotObject.writeReferenceToSlot((omrobjectptr_t)arraylet);
+			arrayletSlotObject.writeReferenceToSlot((omrobjectptr_t)arraylet);
+			arrayletSlotObject.addToSlotAddress(1);
 			bytesRemaining = MM_Math::saturatingSubtract(bytesRemaining, arrayletLeafSize);
 		}
 	}