fixup! p: NULL initialize dataAddr field for 0 size arrays

eclipse-openj9 · Jan 3, 2025 · 1317bac · 1317bac
1 parent 519bedd
commit 1317bac
Showing 1 changed file with 18 additions and 17 deletions.
diff --git a/runtime/compiler/p/codegen/J9TreeEvaluator.cpp b/runtime/compiler/p/codegen/J9TreeEvaluator.cpp
@@ -6165,23 +6165,24 @@ static void genInitArrayHeader(TR::Node *node, TR::Instruction *&iCursor, bool i
       }
 
    // Clear padding after size field
-   TR::Register *zeroReg = cg->allocateRegister();
-   iCursor = generateTrg1Src2Instruction(cg, TR::InstOpCode::XOR, node, zeroReg, zeroReg, zeroReg, iCursor);
-   if (TR::Compiler->om.compressObjectReferences())
-      {
-      // use fej9->getOffsetOfDiscontiguousArraySizeField() + 4
-      iCursor = generateMemSrc1Instruction(cg, TR::InstOpCode::stw, node,
-                                       TR::MemoryReference::createWithDisplacement(cg, resReg, fej9->getOffsetOfDiscontiguousArraySizeField() + 4, 4),
-                                       zeroReg, iCursor);
-      }
-   else
+   if (needZeroInit)
       {
-      // use fej9->getOffsetOfContiguousArraySizeField() + 4
-      iCursor = generateMemSrc1Instruction(cg, TR::InstOpCode::stw, node,
-                                       TR::MemoryReference::createWithDisplacement(cg, resReg, fej9->getOffsetOfContiguousArraySizeField() + 4, 4),
-                                       zeroReg, iCursor);
+      TR_ASSERT_FATAL_WITH_NODE(node, zeroReg, "zeroReg is expected to be intialized but wasn't.\n");
+      if (TR::Compiler->om.compressObjectReferences())
+         {
+         // padding field starts at fej9->getOffsetOfDiscontiguousArraySizeField() + 4
+         iCursor = generateMemSrc1Instruction(cg, TR::InstOpCode::stw, node,
+                                          TR::MemoryReference::createWithDisplacement(cg, resReg, fej9->getOffsetOfDiscontiguousArraySizeField() + 4, 4),
+                                          zeroReg, iCursor);
+         }
+      else
+         {
+         // padding field starts at fej9->getOffsetOfContiguousArraySizeField() + 4
+         iCursor = generateMemSrc1Instruction(cg, TR::InstOpCode::stw, node,
+                                          TR::MemoryReference::createWithDisplacement(cg, resReg, fej9->getOffsetOfContiguousArraySizeField() + 4, 4),
+                                          zeroReg, iCursor);
+         }
       }
-   cg->stopUsingRegister(zeroReg);
    }
 
 static void genZeroInit(TR::CodeGenerator *cg, TR::Node *node, TR::Register *objectReg, int32_t headerSize, int32_t totalSize, bool useInitInfo)
@@ -6541,7 +6542,7 @@ TR::Register *J9::Power::TreeEvaluator::VMnewEvaluator(TR::Node *node, TR::CodeG
                dataAddrSlotMR = TR::MemoryReference::createWithDisplacement(cg, offsetReg, fej9->getOffsetOfContiguousDataAddrField(), TR::Compiler->om.sizeofReferenceAddress());
 
                // Clear firstDataElementReg reg if dealing with 0 size arrays
-               iCursor = generateTrg1Src1ImmInstruction(cg,TR::InstOpCode::Op_cmpdi, node, condReg, enumReg, 0, iCursor);
+               iCursor = generateTrg1Src1ImmInstruction(cg,TR::InstOpCode::cmpi8, node, condReg, enumReg, 0, iCursor);
                iCursor = generateTrg1Src3Instruction(cg, TR::InstOpCode::iseleq, node, firstDataElementReg, NULL, firstDataElementReg, condReg, iCursor);
                }
             else if (!isVariableLen && node->getFirstChild()->getOpCode().isLoadConst() && node->getFirstChild()->getInt() == 0)
@@ -6579,7 +6580,7 @@ TR::Register *J9::Power::TreeEvaluator::VMnewEvaluator(TR::Node *node, TR::CodeG
                // Clear firstDataElementReg reg if dealing with variable len 0 size arrays
                if (isVariableLen && !TR::Compiler->om.compressObjectReferences())
                   {
-                  iCursor = generateTrg1Src1ImmInstruction(cg,TR::InstOpCode::Op_cmpdi, node, condReg, enumReg, 0, iCursor);
+                  iCursor = generateTrg1Src1ImmInstruction(cg,TR::InstOpCode::cmpi8, node, condReg, enumReg, 0, iCursor);
                   iCursor = generateTrg1Src3Instruction(cg, TR::InstOpCode::iseleq, node, firstDataElementReg, NULL, firstDataElementReg, condReg, iCursor);
                   }
                }