From 8659ab310af09a6ef10b820e565a7d92fe45b12c Mon Sep 17 00:00:00 2001
From: Aleksandar Micic <Aleksandar_Micic@ca.ibm.com>
Date: Mon, 20 Jan 2025 12:13:57 -0500
Subject: [PATCH] Force outlining for array EA API

Signed-off-by: Aleksandar Micic <Aleksandar_Micic@ca.ibm.com>
---
 runtime/oti/j9accessbarrier.h        | 14 +++---
 runtime/oti/j9accessbarrierhelpers.h | 66 ++++++++++++++++++++++++++++
 2 files changed, 72 insertions(+), 8 deletions(-)

diff --git a/runtime/oti/j9accessbarrier.h b/runtime/oti/j9accessbarrier.h
index 86eb5494ed9..befcc3f0cee 100644
--- a/runtime/oti/j9accessbarrier.h
+++ b/runtime/oti/j9accessbarrier.h
@@ -161,14 +161,12 @@ typedef struct J9IndexableObject* mm_j9array_t;
  * 		else
  * 			discontiguous
  */
-#define J9JAVAARRAY_EA(vmThread, array, index, elemType) \
-	((J9IndexableObjectLayout_NoDataAddr_NoArraylet == (vmThread)->indexableObjectLayout) \
-		? J9JAVAARRAYCONTIGUOUS_BASE_EA(vmThread, array, index, elemType) \
-		: ((J9IndexableObjectLayout_DataAddr_NoArraylet == (vmThread)->indexableObjectLayout) \
-			? J9JAVAARRAYCONTIGUOUS_WITH_DATAADDRESS_VIRTUALLARGEOBJECTHEAPENABLED_EA(vmThread, array, index, elemType) \
-			: (J9ISCONTIGUOUSARRAY(vmThread, array) \
-				? J9JAVAARRAYCONTIGUOUS_EA(vmThread, array, index, elemType) \
-				: J9JAVAARRAYDISCONTIGUOUS_EA(vmThread, array, index, elemType))))
+
+
+
+/* There are lots of callers of this macro passing index as UDATA?! While callers keeping index in UDATA is probably overkill,
+ * we simply explicitly cast down to U_32 (what C helpers use) to avoid compiler loss of precision warning */
+#define J9JAVAARRAY_EA(vmThread, array, index, elemType) j9javaArray_##elemType##_EA(vmThread, (J9IndexableObject *)array, (U_32)index)
 
 #define J9JAVAARRAY_EA_VM(javaVM, array, index, elemType) \
 	((J9IndexableObjectLayout_NoDataAddr_NoArraylet == (javaVM)->indexableObjectLayout) \
diff --git a/runtime/oti/j9accessbarrierhelpers.h b/runtime/oti/j9accessbarrierhelpers.h
index e97a2efbea0..0fffa333a44 100644
--- a/runtime/oti/j9accessbarrierhelpers.h
+++ b/runtime/oti/j9accessbarrierhelpers.h
@@ -23,6 +23,72 @@
 #ifndef J9ACCESSBARRIERHELPERS_H
 #define J9ACCESSBARRIERHELPERS_H
 
+#if defined (J9VM_ENV_DATA64)
+#if (defined(__GNUC__) && (defined(J9X86) || defined(S390)))
+#endif /* (defined(__GNUC__) && defined(J9X86)) */
+__attribute__ ((noinline))
+static UDATA j9javaArray_BA(J9VMThread *vmThread, J9IndexableObject *array, U_32 *index, U_8 elementSize)
+{
+	UDATA baseAddress = (UDATA)array;
+
+	if (J9VMTHREAD_COMPRESS_OBJECT_REFERENCES(vmThread)) {
+		baseAddress += sizeof(J9IndexableObjectContiguousCompressed);
+	} else {
+		baseAddress += sizeof(J9IndexableObjectContiguousFull);
+	}
+
+	if (J9IndexableObjectLayout_NoDataAddr_NoArraylet == vmThread->indexableObjectLayout) {
+		/* Standard GCs */
+	} else if (J9IndexableObjectLayout_DataAddr_NoArraylet == vmThread->indexableObjectLayout) {
+		/* Balanced Offheap; dereference dataAddr that is just after the (base) header */
+		baseAddress = *(UDATA *)baseAddress;
+	} else {
+		/* GCs that may have arraylet (Balanced arraylet or Metronome) - will recalculate baseAddress from scratch */
+		if (J9ISCONTIGUOUSARRAY(vmThread, array)) {
+			baseAddress = (UDATA)array + vmThread->contiguousIndexableHeaderSize;
+		} else {
+			fj9object_t *arrayoid = (fj9object_t *)((UDATA)array + vmThread->discontiguousIndexableHeaderSize);
+			/* While arrayletLeafSize is UDATA, the result of this division will fit into U_32 (simply because Java can't have more array elements) */
+			U_32 elementsPerLeaf = (U_32)(J9VMTHREAD_JAVAVM(vmThread)->arrayletLeafSize / elementSize);
+			U_32 leafIndex = *index / elementsPerLeaf;
+			*index = *index % elementsPerLeaf;
+
+			if (J9VMTHREAD_COMPRESS_OBJECT_REFERENCES(vmThread)) {
+				U_32 leafToken = *((U_32 *)arrayoid + leafIndex);
+				baseAddress = (UDATA)J9_CONVERT_POINTER_FROM_TOKEN__(vmThread, leafToken);
+			} else {
+				UDATA leafToken = *((UDATA *)arrayoid + leafIndex);
+				baseAddress = leafToken;
+			}
+		}
+	}
+
+
+	return baseAddress;
+}
+
+#define J9JAVAARRAY_C_EA(elemType)																					\
+VMINLINE static elemType *j9javaArray_##elemType##_EA(J9VMThread *vmThread, J9IndexableObject *array, U_32 index)	\
+{																													\
+	UDATA baseAddress = j9javaArray_BA(vmThread, array, &index, (U_8)sizeof(elemType));								\
+	/* intentionally inlining this to treat sizeof value as an immediate */											\
+	return (elemType *)(baseAddress + (UDATA)index * sizeof(elemType));												\
+} 																													\
+
+/* generate C bodies */
+
+J9JAVAARRAY_C_EA(I_8)
+J9JAVAARRAY_C_EA(U_8)
+J9JAVAARRAY_C_EA(I_16)
+J9JAVAARRAY_C_EA(U_16)
+J9JAVAARRAY_C_EA(I_32)
+J9JAVAARRAY_C_EA(U_32)
+J9JAVAARRAY_C_EA(I_64)
+J9JAVAARRAY_C_EA(U_64)
+J9JAVAARRAY_C_EA(IDATA)
+J9JAVAARRAY_C_EA(UDATA)
+#endif /* defined (J9VM_ENV_DATA64) */
+
 /**
  * These helpers could be written as macros (where the body of methods would be wrapped around oval parenthesis, which would mean that the last expression in the block
  * is return value of the block). However, it is not fully supported by ANSI, but only select C compilers, like GNU C: https://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html).