Prepare for value objects to be created with new bytecode

This change sets up changes to the JIT compiler that are needed to permit value objects to be created with the new bytecode. Previously they could only be created with the aconst_init and withfield bytecode instructions. The new bytecode will be translated to the TR::New opcode in IL, but existing optimizations that create value type instances will continue to use the TR::newvalue opcode, so optimizations need to be prepared for both possibilities for now. Signed-off-by: Theresa Mammarella <[email protected]>
eclipse-openj9 · Jul 5, 2024 · c00260e · c00260e
1 parent ab95037
commit c00260e
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Showing 4 changed files with 26 additions and 9 deletions.
diff --git a/runtime/compiler/compile/J9Compilation.cpp b/runtime/compiler/compile/J9Compilation.cpp
@@ -734,8 +734,8 @@ J9::Compilation::canAllocateInline(TR::Node* node, TR_OpaqueClassBlock* &classIn
       if (clazz == NULL)
          return -1;
 
-      // Arrays of primitive value type classes must have all their elements initialized with the
-      // default value of the component type.  For now, prevent inline allocation of them.
+      // Arrays of null-restricted (a.k.a, primitive value type) classes must have all their elements initialized
+      // with the default value of the component type.  For now, prevent inline allocation of them.
       //
       if (areValueTypesEnabled && TR::Compiler->cls.isPrimitiveValueTypeClass(reinterpret_cast<TR_OpaqueClassBlock*>(clazz)))
          {

diff --git a/runtime/compiler/env/J9ObjectModel.hpp b/runtime/compiler/env/J9ObjectModel.hpp
@@ -63,20 +63,23 @@ class ObjectModel : public OMR::ObjectModelConnector
    bool mayRequireSpineChecks();
 
    /**
-   * @brief Whether or not value object is enabled
-   */
+    * @brief Whether or not value object is enabled
+    */
    bool areValueTypesEnabled();
+
    /**
-   * @brief Whether or not flattenable value object (aka null restricted) type is enabled
-   */
+    * @brief Whether or not flattenable value object (aka null restricted) type is enabled
+    */
    bool areFlattenableValueTypesEnabled();
+
    /**
    * @brief Whether the check is enabled on monitor object being value based class type
    */
    bool areValueBasedMonitorChecksEnabled();
+
    /**
-   * @brief Whether the array flattening is enabled for value types
-   */
+    * @brief Whether the array flattening is enabled for value types
+    */
    bool isValueTypeArrayFlatteningEnabled();
 
    int32_t sizeofReferenceField();

diff --git a/runtime/compiler/ilgen/Walker.cpp b/runtime/compiler/ilgen/Walker.cpp
@@ -6272,6 +6272,12 @@ TR_J9ByteCodeIlGenerator::genNew(TR::ILOpCodes opCode)
    if (!node->getFirstChild()->getSymbolReference()->isUnresolved() && node->getFirstChild()->getSymbol()->isStatic())
       {
       TR_OpaqueClassBlock *clazz = (TR_OpaqueClassBlock*)node->getFirstChild()->getSymbol()->castToStaticSymbol()->getStaticAddress();
+
+      if (TR::Compiler->cls.isValueTypeClass(clazz))
+         {
+         node->setIdentityless(true);
+         }
+
       int32_t len;
       char *sig;
       sig = TR::Compiler->cls.classSignature_DEPRECATED(comp(), clazz, len, comp()->trMemory());

diff --git a/runtime/compiler/optimizer/EscapeAnalysis.cpp b/runtime/compiler/optimizer/EscapeAnalysis.cpp
@@ -191,7 +191,15 @@ bool TR_EscapeAnalysis::isImmutableObject(TR::Node *node)
       return false;
       }
 
-   char *className = getClassName(node->getFirstChild());
+   TR::Node *classNode = node->getFirstChild();
+
+   TR_OpaqueClassBlock *clazz = (TR_OpaqueClassBlock *)classNode->getSymbol()->getStaticSymbol()->getStaticAddress();
+   if (TR::Compiler->cls.isValueTypeClass(clazz))
+      {
+      return true;
+      }
+
+   char *className = getClassName(classNode);
 
    if (NULL != className &&
           !strncmp("java/lang/", className, 10) &&