001 /*
002 * Copyright 2010-2015 JetBrains s.r.o.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 * http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017 package org.jetbrains.kotlin.codegen;
018
019 import com.google.common.collect.Lists;
020 import org.jetbrains.annotations.NotNull;
021 import org.jetbrains.kotlin.cfg.TailRecursionKind;
022 import org.jetbrains.kotlin.codegen.context.MethodContext;
023 import org.jetbrains.kotlin.codegen.state.GenerationState;
024 import org.jetbrains.kotlin.descriptors.CallableDescriptor;
025 import org.jetbrains.kotlin.descriptors.FunctionDescriptor;
026 import org.jetbrains.kotlin.descriptors.ValueParameterDescriptor;
027 import org.jetbrains.kotlin.psi.KtExpression;
028 import org.jetbrains.kotlin.psi.KtSimpleNameExpression;
029 import org.jetbrains.kotlin.psi.ValueArgument;
030 import org.jetbrains.kotlin.resolve.calls.callUtil.CallUtilKt;
031 import org.jetbrains.kotlin.resolve.calls.model.*;
032 import org.jetbrains.org.objectweb.asm.Type;
033 import org.jetbrains.org.objectweb.asm.commons.InstructionAdapter;
034
035 import java.util.List;
036
037 import static org.jetbrains.kotlin.resolve.BindingContext.TAIL_RECURSION_CALL;
038
039 public class TailRecursionCodegen {
040
041 @NotNull
042 private final MethodContext context;
043 @NotNull
044 private final ExpressionCodegen codegen;
045 @NotNull
046 private final InstructionAdapter v;
047 @NotNull
048 private final GenerationState state;
049
050 public TailRecursionCodegen(
051 @NotNull MethodContext context,
052 @NotNull ExpressionCodegen codegen,
053 @NotNull InstructionAdapter v,
054 @NotNull GenerationState state
055 ) {
056 this.context = context;
057 this.codegen = codegen;
058 this.v = v;
059 this.state = state;
060 }
061
062 public boolean isTailRecursion(@NotNull ResolvedCall<?> resolvedCall) {
063 TailRecursionKind status = state.getBindingContext().get(TAIL_RECURSION_CALL, resolvedCall);
064 return status != null && status.isDoGenerateTailRecursion();
065 }
066
067 public void generateTailRecursion(ResolvedCall<?> resolvedCall) {
068 CallableDescriptor fd = resolvedCall.getResultingDescriptor();
069 assert fd instanceof FunctionDescriptor : "Resolved call doesn't refer to the function descriptor: " + fd;
070 CallableMethod callable = (CallableMethod) codegen.resolveToCallable((FunctionDescriptor) fd, false, resolvedCall);
071
072 List<ResolvedValueArgument> arguments = resolvedCall.getValueArgumentsByIndex();
073 if (arguments == null) {
074 throw new IllegalStateException("Failed to arrange value arguments by index: " + fd);
075 }
076 assignParameterValues(fd, callable, arguments);
077 if (callable.getExtensionReceiverType() != null) {
078 if (resolvedCall.getExtensionReceiver() != fd.getExtensionReceiverParameter().getValue()) {
079 StackValue expression = context.getReceiverExpression(codegen.typeMapper);
080 expression.store(StackValue.onStack(callable.getExtensionReceiverType()), v, true);
081 }
082 else {
083 AsmUtil.pop(v, callable.getExtensionReceiverType());
084 }
085 }
086
087 if (callable.getDispatchReceiverType() != null) {
088 AsmUtil.pop(v, callable.getDispatchReceiverType());
089 }
090
091 v.goTo(context.getMethodStartLabel());
092 }
093
094 private void assignParameterValues(
095 CallableDescriptor fd,
096 CallableMethod callableMethod,
097 List<ResolvedValueArgument> valueArguments
098 ) {
099 List<Type> types = callableMethod.getValueParameterTypes();
100 for (ValueParameterDescriptor parameterDescriptor : Lists.reverse(fd.getValueParameters())) {
101 ResolvedValueArgument arg = valueArguments.get(parameterDescriptor.getIndex());
102 Type type = types.get(parameterDescriptor.getIndex());
103
104 if (arg instanceof ExpressionValueArgument) {
105 ExpressionValueArgument ev = (ExpressionValueArgument) arg;
106 ValueArgument argument = ev.getValueArgument();
107 KtExpression argumentExpression = argument == null ? null : argument.getArgumentExpression();
108
109 if (argumentExpression instanceof KtSimpleNameExpression) {
110 ResolvedCall<?> resolvedCall = CallUtilKt.getResolvedCall(argumentExpression, state.getBindingContext());
111 if (resolvedCall != null && resolvedCall.getResultingDescriptor().equals(parameterDescriptor.getOriginal())) {
112 // do nothing: we shouldn't store argument to itself again
113 AsmUtil.pop(v, type);
114 continue;
115 }
116 }
117 //assign the parameter below
118 }
119 else if (arg instanceof DefaultValueArgument) {
120 AsmUtil.pop(v, type);
121 DefaultParameterValueLoader.DEFAULT.genValue(parameterDescriptor, codegen).put(type, v);
122 }
123 else if (arg instanceof VarargValueArgument) {
124 // assign the parameter below
125 }
126 else {
127 throw new UnsupportedOperationException("Unknown argument type: " + arg + " in " + fd);
128 }
129
130 store(parameterDescriptor, type);
131 }
132 }
133
134 private void store(ValueParameterDescriptor parameterDescriptor, Type type) {
135 int index = getParameterVariableIndex(parameterDescriptor);
136 v.store(index, type);
137 }
138
139 private int getParameterVariableIndex(ValueParameterDescriptor parameterDescriptor) {
140 int index = codegen.lookupLocalIndex(parameterDescriptor);
141 if (index == -1) {
142 // in the case of a generic function recursively calling itself, the parameters on the call site are substituted
143 index = codegen.lookupLocalIndex(parameterDescriptor.getOriginal());
144 }
145
146 if (index == -1) {
147 throw new IllegalStateException("Failed to obtain parameter index: " + parameterDescriptor);
148 }
149
150 return index;
151 }
152 }