Misc zOS system linkage code simplifications

1. Simplify NOP and call descriptor generation for zOS system linkage. 2. Use the insetPad() API to insert NOP after the BASR call in system linkage. 3. Remove createCallDescriptor() function and do the same thing inline. 4. genCallNOPAndDescriptor() does not have to be virtual. Remove the virtual keyword. Signed-off-by: Nigel Yu <yunigel@ca.ibm.com>
eclipse-openj9 · Mar 25, 2018 · cc5dc68 · cc5dc68
1 parent 77c2e36
commit cc5dc68
Show file tree

Hide file tree

Showing 2 changed files with 24 additions and 64 deletions.
diff --git a/runtime/compiler/trj9/z/codegen/J9S390SystemLinkage.cpp b/runtime/compiler/trj9/z/codegen/J9S390SystemLinkage.cpp
@@ -296,7 +296,6 @@ TR::J9S390zOSSystemLinkage::generateInstructionsForCall(TR::Node * callNode, TR:
    TR::Register * systemEnvironmentRegister = javaStackRegister;
    TR::Register * javaLitPoolRegister = privateLinkage->getLitPoolRealRegister();
    bool passLitPoolReg = false;
-   TR_XPLinkCallTypes callType;  // for XPLink calls
 
    if (codeGen->isLiteralPoolOnDemandOn())
       {
@@ -417,21 +416,9 @@ TR::J9S390zOSSystemLinkage::generateInstructionsForCall(TR::Node * callNode, TR:
    if (isJNIGCPoint)
          gcPoint->setNeedsGCMap(0x00000000);
 
-   callType = TR_XPLinkCallType_BASR;
-
-   generateS390LabelInstruction(codeGen, TR::InstOpCode::LABEL, callNode, returnFromJNICallLabel);
-
-   TR::Instruction * cursor = NULL;
-   if (TR::Compiler->target.is64Bit())
-      {
-      //In 64 bit XPLINK, the caller returns at RetAddr+2, so add 2 byte nop
-      cursor = new (trHeapMemory()) TR::S390NOPInstruction(TR::InstOpCode::NOP, 2, callNode, codeGen);
-      }
-   else
-      {
-      cursor = genCallNOPAndDescriptor(NULL, callNode, callNode, callType);
-      }
+   TR::Instruction * cursor = generateS390LabelInstruction(codeGen, TR::InstOpCode::LABEL, callNode, returnFromJNICallLabel);
 
+   cursor = genCallNOPAndDescriptor(cursor, callNode, callNode, TR_XPLinkCallType_BASR);
    cursor->setDependencyConditions(callPostDeps);
 
    if (cg()->supportsJITFreeSystemStackPointer())
@@ -526,64 +513,38 @@ TR::J9S390zOSSystemLinkage::addFECustomizedReturnRegDependency(int64_t killMask,
  * General XPLink utility
  */
 TR::Instruction *
-TR::J9S390zOSSystemLinkage::genCallNOPAndDescriptor(TR::Instruction * cursor, TR::Node *node, TR::Node *callNode, TR_XPLinkCallTypes callType)
+TR::J9S390zOSSystemLinkage::genCallNOPAndDescriptor(TR::Instruction * cursor,
+                                                    TR::Node *node,
+                                                    TR::Node *callNode,
+                                                    TR_XPLinkCallTypes callType)
    {
    TR::CodeGenerator * codeGen = cg();
-   TR::S390NOPInstruction *nop;
+   // In 64 bit XPLINK, the caller returns at RetAddr+2, so add 2 byte nop
+   // In 31 bit XPLINK, the caller returns at RetAddr+4, so add 4 byte nop with last two bytes
+   // as signed offset in doublewords at or preceding NOP
+   uint32_t padSize = TR::Compiler->target.is64Bit() ? 2 : 4;
 
-   if (TR::Compiler->target.is64Bit())
-      {
-      //In 64 bit XPLINK, the caller returns at RetAddr+2, so add 2 byte nop
-      cursor = nop = new (trHeapMemory()) TR::S390NOPInstruction(TR::InstOpCode::NOP, 2, node, cursor, codeGen);
-      }
-   else
+   cursor = codeGen->insertPad(node, cursor, padSize, false);
+   TR::S390NOPInstruction *nop = static_cast<TR::S390NOPInstruction *>(cursor);
+
+   if (TR::Compiler->target.is32Bit())
       {
-      //In 31 bit XPLINK, the caller returns at RetAddr+4, so add 4 byte nop with last two bytes
-      // as signed offset in doublewords at or preceding NOP
-      TR::S390ConstantDataSnippet *callDescSnippet ;
       uint32_t callDescValues = calculateCallDescriptorFlags(callNode);  // lower 32 bits
 
-      callDescSnippet = createCallDescriptor(node, (uint64_t)callDescValues);
-      if (cursor != NULL) // TBD: this is needed but need to understand  why - problem in else case if remove this and provide NULL cursor to the following constructor
-         cursor = nop = new (trHeapMemory()) TR::S390NOPInstruction(TR::InstOpCode::NOP, 4, callDescSnippet, node, cursor, codeGen);
-      else
-         cursor = nop = new (trHeapMemory()) TR::S390NOPInstruction(TR::InstOpCode::NOP, 4, callDescSnippet, node, codeGen);
-
-      // Check if we are emitting warm code.  Mark Snippet as warm snippet if necessary.
-
+      TR::S390ConstantDataSnippet * callDescSnippet = cg()->findOrCreate8ByteConstant(node, (int64_t)callDescValues, false);
+      nop->setTargetSnippet(callDescSnippet);
 
       // Create a pseudo instruction that will generate
       //      BRAS 4
       //      DC <Call Descriptor>
       // if the snippet is > 15k bytes away.
-      if (cursor != NULL)
-         {
-         TR::S390PseudoInstruction *pseudoCallDesc = (TR::S390PseudoInstruction *)generateS390PseudoInstruction(codeGen, TR::InstOpCode::XPCALLDESC, node, NULL, cursor);
-         // Assign this pseudoCallDesc to the NOP Instruction.
-         ((TR::S390NOPInstruction *)cursor)->setCallDescInstr(pseudoCallDesc);
-         cursor = pseudoCallDesc;
-         }
-      else
-         {
-         TR::S390PseudoInstruction *pseudoCallDesc = (TR::S390PseudoInstruction *)generateS390PseudoInstruction(codeGen, TR::InstOpCode::XPCALLDESC, node);
-         // Assign this pseudoCallDesc to the NOP Instruction.
-         ((TR::S390NOPInstruction *)cursor)->setCallDescInstr(pseudoCallDesc);
-         }
+
+      TR::S390PseudoInstruction *pseudoCallDesc = static_cast<TR::S390PseudoInstruction *>(generateS390PseudoInstruction(codeGen, TR::InstOpCode::XPCALLDESC, node, NULL, cursor));
+      // Assign this pseudoCallDesc to the NOP Instruction.
+      static_cast<TR::S390NOPInstruction *>(cursor)->setCallDescInstr(pseudoCallDesc);
+      cursor = pseudoCallDesc;
       }
+
    nop->setCallType(callType);
    return cursor;
    }
-
-/**
- * General XPLink utility
- *
- * Create the XPLink descriptor that is realized in binary as an
- * 8 byte value
- */
-TR::S390ConstantDataSnippet *
-TR::J9S390zOSSystemLinkage::createCallDescriptor(TR::Node *node, uint64_t initialValue)
-   {
-   TR::S390ConstantDataSnippet *desc;
-   desc = (TR::S390ConstantDataSnippet *) cg()->findOrCreate8ByteConstant(node, (int64_t)initialValue, false);
-   return desc;
-   }
diff --git a/runtime/compiler/trj9/z/codegen/J9S390SystemLinkage.hpp b/runtime/compiler/trj9/z/codegen/J9S390SystemLinkage.hpp
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2000, 2016 IBM Corp. and others
+ * Copyright (c) 2000, 2018 IBM Corp. and others
  *
  * This program and the accompanying materials are made available under
  * the terms of the Eclipse Public License 2.0 which accompanies this
@@ -98,8 +98,7 @@ class J9S390zOSSystemLinkage: public TR::S390zOSSystemLinkage
    virtual int32_t storeExtraEnvRegForBuildArgs(TR::Node * callNode, TR::Linkage* linkage, TR::RegisterDependencyConditions * dependencies,
          bool isFastJNI, int32_t stackOffset, int8_t gprSize, uint32_t &numIntegerArgs);
 
-   virtual TR::Instruction * genCallNOPAndDescriptor(TR::Instruction * cursor, TR::Node *node, TR::Node *callNode, TR_XPLinkCallTypes callType);
-   virtual TR::S390ConstantDataSnippet *createCallDescriptor(TR::Node *node, uint64_t initialValue);
+   TR::Instruction * genCallNOPAndDescriptor(TR::Instruction * cursor, TR::Node *node, TR::Node *callNode, TR_XPLinkCallTypes callType);
    };
 
 }