Update CRC32C acceleration for off-heap

The acceleration was initially disabled because it added array header
size to the array object, which was required to reach the elements.
However, this is unnecessary for off-heap mode. As a result, the
evaluator has been updated to add the array header size exclusively
for non-off-heap mode, while in off-heap mode, it now retrieves the
data element address directly from the array header, enabling
acceleration in off-heap mode.

Signed-off-by: Shubham Verma <[email protected]>

Author: VermaSh

runtime/compiler/z/codegen/J9CodeGenerator.cpp

@@ -3734,7 +3734,7 @@ J9::Z::CodeGenerator::suppressInliningOfRecognizedMethod(TR::RecognizedMethod me
       }
 
    static bool disableCRC32CAcceleration = (feGetEnv("TR_DisableCRC32CAcceleration") != NULL);
-   if (!disableCRC32CAcceleration && self()->getSupportsVectorRegisters() && !TR::Compiler->om.canGenerateArraylets() && !TR::Compiler->om.isOffHeapAllocationEnabled())
+   if (!disableCRC32CAcceleration && self()->getSupportsVectorRegisters() && !TR::Compiler->om.canGenerateArraylets())
       {
       if (method == TR::java_util_zip_CRC32C_updateBytes ||
          method == TR::java_util_zip_CRC32C_updateDirectByteBuffer)

runtime/compiler/z/codegen/J9TreeEvaluator.cpp

@@ -2231,10 +2231,27 @@ J9::Z::TreeEvaluator::inlineCRC32CUpdateBytes(TR::Node *node, TR::CodeGenerator
    generateRREInstruction(cg, TR::InstOpCode::LLGFR, node, offset, offset);
    generateRREInstruction(cg, TR::InstOpCode::LLGFR, node, end, end);
 
+   // Offset to be added to array object pointer to get to the data elements
+   int32_t offsetToDataElements = isDirectBuffer ? 0 : TR::Compiler->om.contiguousArrayHeaderSizeInBytes();
+#ifdef J9VM_GC_SPARSE_HEAP_ALLOCATION
+   if (TR::Compiler->om.isOffHeapAllocationEnabled())
+      {
+      // Load first data element address
+      generateRXInstruction(cg,
+         TR::InstOpCode::getLoadOpCode(),
+         node,
+         array,
+         generateS390MemoryReference(array, cg->comp()->fej9()->getOffsetOfContiguousDataAddrField(), cg));
+
+      // Since the first data element address is retrieved from the array header, the offset is set to 0
+      offsetToDataElements = 0;
+      }
+#endif /* J9VM_GC_SPARSE_HEAP_ALLOCATION */
+
    // Calculate buffer pointer = array + offset
-   // For updateBytes need to account for array header size
+   // For updateBytes, in non off-heap mode, need to account for array header size
    TR::Register* buffer = cg->allocateRegister();
-   generateRXInstruction(cg, TR::InstOpCode::getLoadAddressOpCode(), node, buffer, generateS390MemoryReference(array, offset, isDirectBuffer ? 0 : TR::Compiler->om.contiguousArrayHeaderSizeInBytes(), cg));
+   generateRXInstruction(cg, TR::InstOpCode::getLoadAddressOpCode(), node, buffer, generateS390MemoryReference(array, offset, offsetToDataElements, cg));
 
    // Adjust remaining count for offset index
    generateRRRInstruction(cg, TR::InstOpCode::getSubtractThreeRegOpCode(), node, remaining, end, offset);