src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.java/src/org/graalvm/compiler/java/JsrScope.java

rev 56282 : [mq]: graal

*** 1,7 ****
  /*
!  * Copyright (c) 2011, 2018, 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
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.
--- 1,7 ----
  /*
!  * Copyright (c) 2011, 2019, 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
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.
*** 22,89 ****
   */
  
  
  package org.graalvm.compiler.java;
  
! public class JsrScope {
  
      public static final JsrScope EMPTY_SCOPE = new JsrScope();
  
!     private final long scope;
  
!     private JsrScope(long scope) {
!         this.scope = scope;
      }
  
!     public JsrScope() {
!         this.scope = 0;
      }
  
      public int nextReturnAddress() {
!         return (int) (scope & 0xffff);
      }
  
!     public JsrScope push(int jsrReturnBci) {
!         if ((scope & 0xffff000000000000L) != 0) {
!             throw new JsrNotSupportedBailout("only four jsr nesting levels are supported");
          }
!         return new JsrScope((scope << 16) | jsrReturnBci);
      }
  
      public boolean isEmpty() {
!         return scope == 0;
      }
  
      public boolean isPrefixOf(JsrScope other) {
!         return (scope & other.scope) == scope;
      }
  
      public JsrScope pop() {
!         return new JsrScope(scope >>> 16);
      }
  
      @Override
      public int hashCode() {
!         return (int) (scope ^ (scope >>> 32));
      }
  
      @Override
      public boolean equals(Object obj) {
          if (this == obj) {
              return true;
          }
!         return obj != null && getClass() == obj.getClass() && scope == ((JsrScope) obj).scope;
      }
  
      @Override
      public String toString() {
          StringBuilder sb = new StringBuilder();
!         long tmp = scope;
!         sb.append(" [");
!         while (tmp != 0) {
!             sb.append(", ").append(tmp & 0xffff);
!             tmp = tmp >>> 16;
          }
!         sb.append(']');
!         return sb.toString();
      }
  }
--- 22,172 ----
   */
  
  
  package org.graalvm.compiler.java;
  
! import org.graalvm.compiler.bytecode.Bytecodes;
  
+ /**
+  * Represents a subroutine entered via {@link Bytecodes#JSR} and exited via {@link Bytecodes#RET}.
+  */
+ public final class JsrScope {
+ 
+     /**
+      * The scope outside of any JSR/RET subroutine.
+      */
      public static final JsrScope EMPTY_SCOPE = new JsrScope();
  
!     private final char returnAddress;
! 
!     private final JsrScope parent;
  
!     private JsrScope(int returnBci, JsrScope parent) {
!         this.returnAddress = (char) returnBci;
!         this.parent = parent;
      }
  
!     private JsrScope() {
!         this.returnAddress = 0;
!         this.parent = null;
      }
  
      public int nextReturnAddress() {
!         return returnAddress;
      }
  
!     /**
!      * Enters a new subroutine from the current scope represented by this object.
!      *
!      * @param returnBci the bytecode address returned to when leaving the new scope
!      * @return an object representing the newly entered scope
!      */
!     public JsrScope push(int returnBci) {
!         if (returnBci == 0) {
!             throw new IllegalArgumentException("A bytecode subroutine cannot have a return address of 0");
          }
!         if (returnBci < 1 || returnBci > 0xFFFF) {
!             throw new IllegalArgumentException("Bytecode subroutine return address cannot be encoded as a char: " + returnBci);
!         }
!         return new JsrScope(returnBci, this);
      }
  
+     /**
+      * Determines if this is the scope outside of any JSR/RET subroutine.
+      */
      public boolean isEmpty() {
!         return returnAddress == 0;
      }
  
+     /**
+      * Gets the ancestry of this scope starting with the {@link #returnAddress} of this scope's most
+      * distant ancestor and ending with the {@link #returnAddress} of this object.
+      *
+      * @return a String where each character is a 16-bit BCI. This value can be converted to an
+      *         {@code int[]} with {@code value.chars().toArray()}.
+      */
+     public String getAncestry() {
+         StringBuilder sb = new StringBuilder();
+         for (JsrScope s = this; s != null; s = s.parent) {
+             if (!s.isEmpty()) {
+                 sb.append(s.returnAddress);
+             }
+         }
+         return sb.reverse().toString();
+     }
+ 
+     /**
+      * Determines if the {@linkplain #getAncestry() ancestry} of this scope is a prefix of the
+      * ancestry of {@code other}.
+      */
      public boolean isPrefixOf(JsrScope other) {
!         if (isEmpty()) {
!             return true;
!         }
!         String ancestry = getAncestry();
!         String otherAncestry = other.getAncestry();
!         return otherAncestry.startsWith(ancestry);
      }
  
+     /**
+      * Gets this scope's parent.
+      *
+      * @return this scope's parent or {@link #EMPTY_SCOPE} if this is the {@link #EMPTY_SCOPE}
+      */
      public JsrScope pop() {
!         if (isEmpty()) {
!             return this;
!         }
!         return parent;
      }
  
      @Override
      public int hashCode() {
!         int hc = returnAddress;
!         JsrScope ancestor = parent;
!         while (ancestor != null) {
!             hc = hc ^ ancestor.returnAddress;
!             ancestor = ancestor.parent;
!         }
!         return hc;
      }
  
      @Override
      public boolean equals(Object obj) {
          if (this == obj) {
              return true;
          }
!         if (obj != null && getClass() == obj.getClass()) {
!             JsrScope ancestor = this;
!             JsrScope otherAncestor = (JsrScope) obj;
!             while (ancestor != null) {
!                 if (otherAncestor == null) {
!                     return false;
!                 }
!                 if (otherAncestor.returnAddress != ancestor.returnAddress) {
!                     return false;
!                 }
!                 ancestor = ancestor.parent;
!                 otherAncestor = otherAncestor.parent;
!             }
!             if (otherAncestor == null) {
!                 return true;
!             }
!         }
!         return false;
      }
  
      @Override
      public String toString() {
          StringBuilder sb = new StringBuilder();
! 
!         for (JsrScope ancestor = this; ancestor != null; ancestor = ancestor.parent) {
!             if (!ancestor.isEmpty()) {
!                 if (sb.length() != 0) {
!                     sb.append(", ");
!                 }
!                 sb.append((int) ancestor.returnAddress);
!             }
          }
!         return "[" + sb + "]";
      }
  }