1 /*
   2  * Copyright (c) 2013, 2015, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 package org.graalvm.compiler.hotspot.replacements;
  24 
  25 import static org.graalvm.compiler.nodeinfo.NodeCycles.CYCLES_UNKNOWN;
  26 import static org.graalvm.compiler.nodeinfo.NodeSize.SIZE_20;
  27 
  28 import org.graalvm.compiler.core.common.type.StampPair;
  29 import org.graalvm.compiler.debug.GraalError;
  30 import org.graalvm.compiler.graph.Node;
  31 import org.graalvm.compiler.graph.NodeClass;
  32 import org.graalvm.compiler.graph.spi.Canonicalizable;
  33 import org.graalvm.compiler.graph.spi.CanonicalizerTool;
  34 import org.graalvm.compiler.nodeinfo.NodeInfo;
  35 import org.graalvm.compiler.nodes.CallTargetNode.InvokeKind;
  36 import org.graalvm.compiler.nodes.ConstantNode;
  37 import org.graalvm.compiler.nodes.FrameState;
  38 import org.graalvm.compiler.nodes.InvokeNode;
  39 import org.graalvm.compiler.nodes.ValueNode;
  40 import org.graalvm.compiler.nodes.spi.Lowerable;
  41 import org.graalvm.compiler.nodes.spi.LoweringTool;
  42 import org.graalvm.compiler.replacements.nodes.MacroStateSplitNode;
  43 
  44 import jdk.vm.ci.hotspot.HotSpotResolvedJavaMethod;
  45 import jdk.vm.ci.hotspot.HotSpotResolvedObjectType;
  46 import jdk.vm.ci.meta.ConstantReflectionProvider;
  47 import jdk.vm.ci.meta.MetaAccessProvider;
  48 import jdk.vm.ci.meta.ResolvedJavaMethod;
  49 
  50 @NodeInfo(cycles = CYCLES_UNKNOWN, cyclesRationale = "This node can be lowered to a call", size = SIZE_20)
  51 public final class ReflectionGetCallerClassNode extends MacroStateSplitNode implements Canonicalizable, Lowerable {
  52 
  53     public static final NodeClass<ReflectionGetCallerClassNode> TYPE = NodeClass.create(ReflectionGetCallerClassNode.class);
  54 
  55     public ReflectionGetCallerClassNode(InvokeKind invokeKind, ResolvedJavaMethod targetMethod, int bci, StampPair returnStamp, ValueNode... arguments) {
  56         super(TYPE, invokeKind, targetMethod, bci, returnStamp, arguments);
  57     }
  58 
  59     @Override
  60     public Node canonical(CanonicalizerTool tool) {
  61         ConstantNode callerClassNode = getCallerClassNode(tool.getMetaAccess(), tool.getConstantReflection());
  62         if (callerClassNode != null) {
  63             return callerClassNode;
  64         }
  65         return this;
  66     }
  67 
  68     @Override
  69     public void lower(LoweringTool tool) {
  70         ConstantNode callerClassNode = getCallerClassNode(tool.getMetaAccess(), tool.getConstantReflection());
  71 
  72         if (callerClassNode != null) {
  73             graph().replaceFixedWithFloating(this, graph().addOrUniqueWithInputs(callerClassNode));
  74         } else {
  75             InvokeNode invoke = createInvoke();
  76             graph().replaceFixedWithFixed(this, invoke);
  77             invoke.lower(tool);
  78         }
  79     }
  80 
  81     /**
  82      * If inlining is deep enough this method returns a {@link ConstantNode} of the caller class by
  83      * walking the the stack.
  84      *
  85      * @param metaAccess
  86      * @return ConstantNode of the caller class, or null
  87      */
  88     private ConstantNode getCallerClassNode(MetaAccessProvider metaAccess, ConstantReflectionProvider constantReflection) {
  89         // Walk back up the frame states to find the caller at the required depth.
  90         FrameState state = stateAfter();
  91 
  92         // Cf. JVM_GetCallerClass
  93         // NOTE: Start the loop at depth 1 because the current frame state does
  94         // not include the Reflection.getCallerClass() frame.
  95         for (int n = 1; state != null; state = state.outerFrameState(), n++) {
  96             HotSpotResolvedJavaMethod method = (HotSpotResolvedJavaMethod) state.getMethod();
  97             switch (n) {
  98                 case 0:
  99                     throw GraalError.shouldNotReachHere("current frame state does not include the Reflection.getCallerClass frame");
 100                 case 1:
 101                     // Frame 0 and 1 must be caller sensitive (see JVM_GetCallerClass).
 102                     if (!method.isCallerSensitive()) {
 103                         return null;  // bail-out; let JVM_GetCallerClass do the work
 104                     }
 105                     break;
 106                 default:
 107                     if (!method.ignoredBySecurityStackWalk()) {
 108                         // We have reached the desired frame; return the holder class.
 109                         HotSpotResolvedObjectType callerClass = method.getDeclaringClass();
 110                         return ConstantNode.forConstant(constantReflection.asJavaClass(callerClass), metaAccess);
 111                     }
 112                     break;
 113             }
 114         }
 115         return null;  // bail-out; let JVM_GetCallerClass do the work
 116     }
 117 
 118 }