[GR-62642] Remove redundant callee saved register spilling.

PullRequest: graal/20452

Author: mur47x111

substratevm/src/com.oracle.svm.hosted.foreign/src/com/oracle/svm/hosted/foreign/ForeignGraphKit.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2023, 2024, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2023, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -27,9 +27,6 @@
 import java.lang.invoke.MethodType;
 import java.util.ArrayList;
 import java.util.List;
-import java.util.Map;
-import java.util.stream.Collectors;
-import java.util.stream.StreamSupport;
 
 import org.graalvm.collections.Pair;
 
@@ -43,8 +40,6 @@
 import jdk.graal.compiler.nodes.extended.PublishWritesNode;
 import jdk.graal.compiler.nodes.java.NewArrayNode;
 import jdk.graal.compiler.replacements.nodes.ReadRegisterNode;
-import jdk.graal.compiler.replacements.nodes.WriteRegisterNode;
-import jdk.vm.ci.amd64.AMD64;
 import jdk.vm.ci.code.Register;
 import jdk.vm.ci.meta.JavaKind;
 import jdk.vm.ci.meta.MetaAccessProvider;
@@ -125,18 +120,4 @@ public ValueNode createReturn(ValueNode returnValue, MethodType methodType) {
     public ValueNode bindRegister(Register register, JavaKind kind) {
         return append(new ReadRegisterNode(register, kind, false, false));
     }
-
-    private JavaKind getRegisterKind(Register register) {
-        // GR-62468: possible incorrect backup/restore of XMM register (Windows only)
-        return AMD64.XMM.equals(register.getRegisterCategory()) ? JavaKind.Double : getWordTypes().getWordKind();
-    }
-
-    public Map<Register, ValueNode> saveRegisters(Iterable<Register> registers) {
-        return StreamSupport.stream(registers.spliterator(), false)
-                        .collect(Collectors.toMap(reg -> reg, register -> bindRegister(register, getRegisterKind(register))));
-    }
-
-    public void restoreRegisters(Map<Register, ValueNode> save) {
-        save.forEach((register, value) -> append(new WriteRegisterNode(register, value)));
-    }
 }

substratevm/src/com.oracle.svm.hosted.foreign/src/com/oracle/svm/hosted/foreign/UpcallStub.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2023, 2024, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2023, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -196,7 +196,6 @@ public StructuredGraph buildGraph(DebugContext debug, AnalysisMethod method, Hos
          */
         assert !savedRegisters.asList().contains(registers.methodHandle());
         assert !savedRegisters.asList().contains(registers.isolate());
-        var save = kit.saveRegisters(savedRegisters);
         ValueNode enterResult = kit.append(CEntryPointEnterNode.attachThread(isolate, false, true));
 
         kit.startIf(IntegerEqualsNode.create(enterResult, ConstantNode.forInt(CEntryPointErrors.NO_ERROR, kit.getGraph()), NodeView.DEFAULT),
@@ -235,8 +234,6 @@ public StructuredGraph buildGraph(DebugContext debug, AnalysisMethod method, Hos
             long offset = 0;
             for (AssignedLocation loc : AbiUtils.create().toMemoryAssignment(jep.returnAssignment(), true)) {
                 assert loc.assignsToRegister();
-                // an output location must not be a callee-save register
-                assert !save.containsKey(loc.register());
 
                 AddressNode address = new OffsetAddressNode(returnBuffer, ConstantNode.forLong(offset, kit.getGraph()));
                 ReadNode val = kit.append(new ReadNode(address, LocationIdentity.any(), StampFactory.forKind(loc.registerKind()), BarrierType.NONE, MemoryOrderMode.PLAIN));
@@ -251,7 +248,6 @@ public StructuredGraph buildGraph(DebugContext debug, AnalysisMethod method, Hos
             assert offset == jep.returnBufferSize();
         }
         kit.append(new CEntryPointLeaveNode(CEntryPointLeaveNode.LeaveAction.Leave));
-        kit.restoreRegisters(save);
         kit.createReturn(returnValue, jep.cMethodType());
 
         return kit.finalizeGraph();