8352690: [JVMCI] Add the set of caller saved registers to j.i.v.c.CallingConvention

src/jdk.internal.vm.ci/share/classes/jdk/vm/ci/code/CallingConvention.java

@@ -24,12 +24,20 @@
 
 import static jdk.vm.ci.code.ValueUtil.isAllocatableValue;
 import static jdk.vm.ci.code.ValueUtil.isStackSlot;
+
+import java.util.Collection;
+import java.util.List;
+import java.util.Objects;
+import java.util.Set;
+
 import jdk.vm.ci.meta.AllocatableValue;
 import jdk.vm.ci.meta.Value;
 
 /**
- * A calling convention describes the locations in which the arguments for a call are placed and the
- * location in which the return value is placed if the call is not void.
+ * A calling convention describes how 2 functions interact with each other at the machine code
+ * level. It contains the locations in which the arguments for a call are placed, the location in
+ * which the return value is placed if the call is not void, and the locations that are killed by
+ * this call (a.k.a. the set of caller-saved registers).
  */
 public class CallingConvention {
 
@@ -49,7 +57,13 @@ public interface Type {
     /**
      * The ordered locations in which the arguments are placed.
      */
-    private final AllocatableValue[] argumentLocations;
+    private final List<? extends AllocatableValue> argumentLocations;
+
+    /**
+     * The set of call-clobbered (caller-saved) registers. If a register is not in this set, it is a
+     * call-preserved (callee-saved) register.
+     */
+    private final Set<? extends AllocatableValue> callerSavedLocations;
 
     /**
      * Creates a description of the registers and stack locations used by a call.
@@ -60,12 +74,13 @@ public interface Type {
      *            call
      * @param argumentLocations the ordered locations in which the arguments are placed
      */
-    public CallingConvention(int stackSize, AllocatableValue returnLocation, AllocatableValue... argumentLocations) {
+    public CallingConvention(int stackSize, AllocatableValue returnLocation, List<? extends AllocatableValue> argumentLocations, Collection<? extends AllocatableValue> callerSavedLocations) {
         assert argumentLocations != null;
         assert returnLocation != null;
-        this.argumentLocations = argumentLocations;
+        this.callerSavedLocations = Set.copyOf(callerSavedLocations);
+        this.argumentLocations = List.copyOf(argumentLocations);
+        this.returnLocation = Objects.requireNonNull(returnLocation);
         this.stackSize = stackSize;
-        this.returnLocation = returnLocation;
         assert verify();
     }
 
@@ -80,7 +95,7 @@ public AllocatableValue getReturn() {
      * Gets the location for the {@code index}'th argument.
      */
     public AllocatableValue getArgument(int index) {
-        return argumentLocations[index];
+        return argumentLocations.get(index);
     }
 
     /**
@@ -94,18 +109,23 @@ public int getStackSize() {
      * Gets the number of locations required for the arguments.
      */
     public int getArgumentCount() {
-        return argumentLocations.length;
+        return argumentLocations.size();
     }
 
     /**
-     * Gets the locations required for the arguments.
+     * Gets the locations required for the arguments. The returned value is an immutable
+     * {@link List}.
      */
-    @SuppressFBWarnings(value = "EI_EXPOSE_REP", justification = "FB false positive")
-    public AllocatableValue[] getArguments() {
-        if (argumentLocations.length == 0) {
-            return argumentLocations;
-        }
-        return argumentLocations.clone();
+    public List<? extends AllocatableValue> getArguments() {
+        return argumentLocations;
+    }
+
+    /**
+     * Get the list of call-clobbered (caller-saved) registers. The returned value is an immutable
+     * {@link Set}.
+     */
+    public Set<? extends AllocatableValue> getCallerSavedLocations() {
+        return callerSavedLocations;
     }
 
     @Override
@@ -125,8 +145,7 @@ public String toString() {
     }
 
     private boolean verify() {
-        for (int i = 0; i < argumentLocations.length; i++) {
-            Value location = argumentLocations[i];
+        for (Value location : argumentLocations) {
             assert isStackSlot(location) || isAllocatableValue(location);
         }
         return true;

src/jdk.internal.vm.ci/share/classes/jdk/vm/ci/hotspot/aarch64/AArch64HotSpotRegisterConfig.java

@@ -295,7 +295,7 @@ private CallingConvention callingConvention(RegisterArray generalParameterRegist
 
         JavaKind returnKind = returnType == null ? JavaKind.Void : returnType.getJavaKind();
         AllocatableValue returnLocation = returnKind == JavaKind.Void ? Value.ILLEGAL : getReturnRegister(returnKind).asValue(valueKindFactory.getValueKind(returnKind.getStackKind()));
-        return new CallingConvention(currentStackOffset, returnLocation, locations);
+        return new CallingConvention(currentStackOffset, returnLocation, List.of(locations), callerSaved.asList().stream().map(Register::asValue).toList());
     }
 
     @Override

src/jdk.internal.vm.ci/share/classes/jdk/vm/ci/hotspot/amd64/AMD64HotSpotRegisterConfig.java

@@ -284,7 +284,7 @@ private CallingConvention callingConvention(RegisterArray generalParameterRegist
 
         JavaKind returnKind = returnType == null ? JavaKind.Void : returnType.getJavaKind();
         AllocatableValue returnLocation = returnKind == JavaKind.Void ? Value.ILLEGAL : getReturnRegister(returnKind).asValue(valueKindFactory.getValueKind(returnKind.getStackKind()));
-        return new CallingConvention(currentStackOffset, returnLocation, locations);
+        return new CallingConvention(currentStackOffset, returnLocation, List.of(locations), callerSaved.asList().stream().map(Register::asValue).toList());
     }
 
     @Override

src/jdk.internal.vm.ci/share/classes/jdk/vm/ci/hotspot/riscv64/RISCV64HotSpotRegisterConfig.java

@@ -266,7 +266,7 @@ private CallingConvention callingConvention(RegisterArray generalParameterRegist
 
         JavaKind returnKind = returnType == null ? JavaKind.Void : returnType.getJavaKind();
         AllocatableValue returnLocation = returnKind == JavaKind.Void ? Value.ILLEGAL : getReturnRegister(returnKind).asValue(valueKindFactory.getValueKind(returnKind.getStackKind()));
-        return new CallingConvention(currentStackOffset, returnLocation, locations);
+        return new CallingConvention(currentStackOffset, returnLocation, List.of(locations), callerSaved.asList().stream().map(Register::asValue).toList());
     }
 
     @Override

test/hotspot/jtreg/compiler/jvmci/jdk.vm.ci.code.test/src/jdk/vm/ci/code/test/aarch64/AArch64TestAssembler.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, 2024, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2020, 2025, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2020, 2023, Arm Limited. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
@@ -367,9 +367,8 @@ public void emitEpilogue() {
     @Override
     public void emitCallPrologue(CallingConvention cc, Object... prim) {
         growFrame(cc.getStackSize());
-        AllocatableValue[] args = cc.getArguments();
-        for (int i = 0; i < args.length; i++) {
-            emitLoad(args[i], prim[i]);
+        for (int i = 0; i < cc.getArgumentCount(); i++) {
+            emitLoad(cc.getArgument(i), prim[i]);
         }
     }
 

test/hotspot/jtreg/compiler/jvmci/jdk.vm.ci.code.test/src/jdk/vm/ci/code/test/amd64/AMD64TestAssembler.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015, 2024, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2015, 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
@@ -495,11 +495,10 @@ public void emitLoad(AllocatableValue av, Object prim) {
     @Override
     public void emitCallPrologue(CallingConvention cc, Object... prim) {
         growFrame(cc.getStackSize());
-        AllocatableValue[] args = cc.getArguments();
         // Do the emission in reverse, this avoids register collisons of xmm0 - which is used a
         // scratch register when putting arguments on the stack.
-        for (int i = args.length - 1; i >= 0; i--) {
-            emitLoad(args[i], prim[i]);
+        for (int i = cc.getArgumentCount() - 1; i >= 0; i--) {
+            emitLoad(cc.getArgument(i), prim[i]);
         }
     }
 

test/hotspot/jtreg/compiler/jvmci/jdk.vm.ci.code.test/src/jdk/vm/ci/code/test/riscv64/RISCV64TestAssembler.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2022, 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
@@ -227,9 +227,8 @@ public void emitEpilogue() {
     @Override
     public void emitCallPrologue(CallingConvention cc, Object... prim) {
         growFrame(cc.getStackSize());
-        AllocatableValue[] args = cc.getArguments();
-        for (int i = 0; i < args.length; i++) {
-            emitLoad(args[i], prim[i]);
+        for (int i = 0; i < cc.getArgumentCount(); i++) {
+            emitLoad(cc.getArgument(i), prim[i]);
         }
     }