1 /*
   2  * Copyright (c) 2010, 2016, 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.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package jdk.nashorn.internal.codegen;
  27 
  28 import static jdk.nashorn.internal.lookup.Lookup.MH;
  29 
  30 import java.lang.invoke.MethodType;
  31 import java.util.ArrayList;
  32 import java.util.List;
  33 import jdk.nashorn.internal.codegen.types.Type;
  34 import jdk.nashorn.internal.ir.Expression;
  35 import jdk.nashorn.internal.ir.FunctionNode;
  36 import jdk.nashorn.internal.runtime.ScriptFunction;
  37 import jdk.nashorn.internal.runtime.linker.LinkerCallSite;
  38 
  39 /**
  40  * Class that generates function signatures for dynamic calls
  41  */
  42 public final class FunctionSignature {
  43 
  44     /** parameter types that ASM can understand */
  45     private final Type[] paramTypes;
  46 
  47     /** return type that ASM can understand */
  48     private final Type returnType;
  49 
  50     /** valid Java descriptor string for function */
  51     private final String descriptor;
  52 
  53     /** {@link MethodType} for function */
  54     private final MethodType methodType;
  55 
  56     /**
  57      * Constructor
  58      *
  59      * Create a FunctionSignature given arguments as AST Nodes
  60      *
  61      * @param hasSelf   does the function have a self slot?
  62      * @param hasCallee does the function need a callee variable
  63      * @param retType   what is the return type
  64      * @param args      argument list of AST Nodes
  65      */
  66     public FunctionSignature(final boolean hasSelf, final boolean hasCallee, final Type retType, final List<? extends Expression> args) {
  67         this(hasSelf, hasCallee, retType, FunctionSignature.typeArray(args));
  68     }
  69 
  70     /**
  71      * Constructor
  72      *
  73      * Create a FunctionSignature given arguments as AST Nodes
  74      *
  75      * @param hasSelf does the function have a self slot?
  76      * @param hasCallee does the function need a callee variable
  77      * @param retType what is the return type
  78      * @param nArgs   number of arguments
  79      */
  80     public FunctionSignature(final boolean hasSelf, final boolean hasCallee, final Type retType, final int nArgs) {
  81         this(hasSelf, hasCallee, retType, FunctionSignature.objectArgs(nArgs));
  82     }
  83 
  84     /**
  85      * Constructor
  86      *
  87      * Create a FunctionSignature given argument types only
  88      *
  89      * @param hasSelf   does the function have a self slot?
  90      * @param hasCallee does the function have a callee slot?
  91      * @param retType   what is the return type
  92      * @param argTypes  argument list of AST Nodes
  93      */
  94     private FunctionSignature(final boolean hasSelf, final boolean hasCallee, final Type retType, final Type... argTypes) {
  95         final boolean isVarArg;
  96 
  97         int count = 1;
  98 
  99         if (argTypes == null) {
 100             isVarArg = true;
 101         } else {
 102             isVarArg = argTypes.length > LinkerCallSite.ARGLIMIT;
 103             count    = isVarArg ? 1 : argTypes.length;
 104         }
 105 
 106         if (hasCallee) {
 107             count++;
 108         }
 109         if (hasSelf) {
 110             count++;
 111         }
 112 
 113         paramTypes = new Type[count];
 114 
 115         int next = 0;
 116         if (hasCallee) {
 117             paramTypes[next++] = Type.typeFor(ScriptFunction.class);
 118         }
 119 
 120         if (hasSelf) {
 121             paramTypes[next++] = Type.OBJECT;
 122         }
 123 
 124         if (isVarArg) {
 125             paramTypes[next] = Type.OBJECT_ARRAY;
 126         } else if (argTypes != null) {
 127             for (int j = 0; next < count;) {
 128                 final Type type = argTypes[j++];
 129                 // TODO: for now, turn java/lang/String into java/lang/Object as we aren't as specific.
 130                 paramTypes[next++] = type.isObject() ? Type.OBJECT : type;
 131             }
 132         } else {
 133             assert false : "isVarArgs cannot be false when argTypes are null";
 134         }
 135 
 136         this.returnType = retType;
 137         this.descriptor = Type.getMethodDescriptor(returnType, paramTypes);
 138 
 139         final List<Class<?>> paramTypeList = new ArrayList<>();
 140         for (final Type paramType : paramTypes) {
 141             paramTypeList.add(paramType.getTypeClass());
 142         }
 143 
 144         this.methodType = MH.type(returnType.getTypeClass(), paramTypeList.toArray(new Class<?>[0]));
 145     }
 146 
 147     /**
 148      * Create a function signature given a function node, using as much
 149      * type information for parameters and return types that is available
 150      *
 151      * @param functionNode the function node
 152      */
 153     public FunctionSignature(final FunctionNode functionNode) {
 154         this(
 155             true,
 156             functionNode.needsCallee(),
 157             functionNode.getReturnType(),
 158             (functionNode.isVarArg() && !functionNode.isProgram()) ?
 159                 null :
 160                 functionNode.getParameters());
 161     }
 162 
 163     /**
 164      * Internal function that converts an array of nodes to their Types
 165      *
 166      * @param args node arg list
 167      *
 168      * @return the array of types
 169      */
 170     private static Type[] typeArray(final List<? extends Expression> args) {
 171         if (args == null) {
 172             return null;
 173         }
 174 
 175         final Type[] typeArray = new Type[args.size()];
 176 
 177         int pos = 0;
 178         for (final Expression arg : args) {
 179             typeArray[pos++] = arg.getType();
 180         }
 181 
 182         return typeArray;
 183     }
 184 
 185     @Override
 186     public String toString() {
 187         return descriptor;
 188     }
 189 
 190     /**
 191      * @return the number of param types
 192      */
 193     public int size() {
 194         return paramTypes.length;
 195     }
 196 
 197     /**
 198      * Get the param types for this function signature
 199      * @return cloned vector of param types
 200      */
 201     public Type[] getParamTypes() {
 202         return paramTypes.clone();
 203     }
 204 
 205     /**
 206      * Return the {@link MethodType} for this function signature
 207      * @return the method type
 208      */
 209     public MethodType getMethodType() {
 210         return methodType;
 211     }
 212 
 213     /**
 214      * Return the return type for this function signature
 215      * @return the return type
 216      */
 217     public Type getReturnType() {
 218         return returnType;
 219     }
 220 
 221     private static Type[] objectArgs(final int nArgs) {
 222         final Type[] array = new Type[nArgs];
 223         for (int i = 0; i < nArgs; i++) {
 224             array[i] = Type.OBJECT;
 225         }
 226         return array;
 227     }
 228 
 229 }