Fix fast ArrayStoreCHK test on Power under AOT

When evaluating an ArrayStoreCHK node, we add a test to see if the array being stored into is an Object[]. When storing to an Object[], there's no need to check the element's class, as all objects can be stored in an Object[]. However, the address for the Object class was being loaded without adding any relocations under AOT, which could cause incorrect behaviour. This has been fixed under SVM AOT, while the fast path is no longer generated under old AOT. Signed-off-by: Ben Thomas <[email protected]>
eclipse-openj9 · Feb 15, 2019 · 073137d · 073137d
1 parent 9c00b45
commit 073137d
Showing 1 changed file with 26 additions and 15 deletions.
diff --git a/runtime/compiler/p/codegen/J9TreeEvaluator.cpp b/runtime/compiler/p/codegen/J9TreeEvaluator.cpp
@@ -3030,31 +3030,42 @@ static void VMarrayStoreCHKEvaluator(TR::Node *node, TR::Register *src, TR::Regi
          new (cg->trHeapMemory()) TR::MemoryReference(dst, (int32_t)TR::Compiler->om.offsetOfObjectVftField(), 4, cg));
    generateTrg1MemInstruction(cg, TR::InstOpCode::lwz, node, t2Reg,
          new (cg->trHeapMemory()) TR::MemoryReference(src, (int32_t)TR::Compiler->om.offsetOfObjectVftField(), 4, cg));
-   TR::TreeEvaluator::generateVFTMaskInstruction(cg, node, t1Reg);
-   TR::TreeEvaluator::generateVFTMaskInstruction(cg, node, t2Reg);
-   // here we may need to convert from class offset contained in t1Reg to
-   // J9Class pointer
-   generateTrg1MemInstruction(cg,TR::InstOpCode::Op_load, node, t1Reg,
-         new (cg->trHeapMemory()) TR::MemoryReference(t1Reg, (int32_t)offsetof(J9ArrayClass, componentType), TR::Compiler->om.sizeofReferenceAddress(), cg));
-   // here we may need to convert from J9Class pointer contained in t1Reg
-   // into class offset (so that we can compare two classes)
 #else
    generateTrg1MemInstruction(cg,TR::InstOpCode::Op_load, node, t1Reg,
          new (cg->trHeapMemory()) TR::MemoryReference(dst, (int32_t) TR::Compiler->om.offsetOfObjectVftField(), TR::Compiler->om.sizeofReferenceAddress(), cg));
    generateTrg1MemInstruction(cg,TR::InstOpCode::Op_load, node, t2Reg,
          new (cg->trHeapMemory()) TR::MemoryReference(src, (int32_t) TR::Compiler->om.offsetOfObjectVftField(), TR::Compiler->om.sizeofReferenceAddress(), cg));
+#endif
    TR::TreeEvaluator::generateVFTMaskInstruction(cg, node, t1Reg);
    TR::TreeEvaluator::generateVFTMaskInstruction(cg, node, t2Reg);
+
    generateTrg1MemInstruction(cg,TR::InstOpCode::Op_load, node, t1Reg,
-         new (cg->trHeapMemory()) TR::MemoryReference(t1Reg, (int32_t) offsetof(J9ArrayClass, componentType), TR::Compiler->om.sizeofReferenceAddress(), cg));
-#endif
+         new (cg->trHeapMemory()) TR::MemoryReference(t1Reg, (int32_t)offsetof(J9ArrayClass, componentType), TR::Compiler->om.sizeofReferenceAddress(), cg));
 
-   TR_OpaqueClassBlock *rootClass = fej9->getSystemClassFromClassName("java/lang/Object", 16);
+   if (!comp->compileRelocatableCode() || comp->getOption(TR_UseSymbolValidationManager))
+      {
+      TR_OpaqueClassBlock *rootClass = fej9->getSystemClassFromClassName("java/lang/Object", 16);
 
-   if (cg->wantToPatchClassPointer(rootClass, node))
-      loadAddressConstantInSnippet(cg, node, (intptrj_t) rootClass, t3Reg, t4Reg,TR::InstOpCode::Op_load, false, NULL);
-   else
-      loadAddressConstant(cg, node, (intptrj_t) rootClass, t3Reg);
+      if (cg->wantToPatchClassPointer(rootClass, node))
+         {
+         loadAddressConstantInSnippet(cg, node, (intptrj_t) rootClass, t3Reg, t4Reg, TR::InstOpCode::Op_load, false, NULL);
+         }
+      else if (comp->compileRelocatableCode())
+         {
+         TR::StaticSymbol *sym = TR::StaticSymbol::create(comp->trHeapMemory(), TR::Address);
+         sym->setStaticAddress(rootClass);
+         sym->setClassObject();
+
+         loadAddressConstant(cg, node, (intptrj_t) new (comp->trHeapMemory()) TR::SymbolReference(comp->getSymRefTab(), sym), t3Reg, NULL, false, TR_ClassAddress);
+         }
+      else
+         {
+         loadAddressConstant(cg, node, (intptrj_t) rootClass, t3Reg);
+         }
+
+      generateTrg1Src2Instruction(cg, TR::InstOpCode::Op_cmpl, node, cndReg, t1Reg, t3Reg);
+      generateConditionalBranchInstruction(cg, TR::InstOpCode::beq, node, toWB, cndReg);
+      }
 
    generateTrg1MemInstruction(cg,TR::InstOpCode::Op_load, node, t4Reg,
          new (cg->trHeapMemory()) TR::MemoryReference(t2Reg, (int32_t) offsetof(J9Class, castClassCache), TR::Compiler->om.sizeofReferenceAddress(), cg));