Convert lambdas to method references when javac compiles a method reference to a lambda #532
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| Original file line number | Diff line number | Diff line change |
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| @@ -0,0 +1,267 @@ | ||
| package org.jetbrains.java.decompiler.modules.decompiler; | ||
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| import org.jetbrains.java.decompiler.code.CodeConstants; | ||
| import org.jetbrains.java.decompiler.code.FullInstructionSequence; | ||
| import org.jetbrains.java.decompiler.code.Instruction; | ||
| import org.jetbrains.java.decompiler.main.ClassesProcessor; | ||
| import org.jetbrains.java.decompiler.main.ClassesProcessor.ClassNode; | ||
| import org.jetbrains.java.decompiler.main.ClassesProcessor.ClassNode.LambdaInformation; | ||
| import org.jetbrains.java.decompiler.main.DecompilerContext; | ||
| import org.jetbrains.java.decompiler.modules.decompiler.exps.*; | ||
| import org.jetbrains.java.decompiler.modules.decompiler.stats.RootStatement; | ||
| import org.jetbrains.java.decompiler.modules.decompiler.stats.Statement; | ||
| import org.jetbrains.java.decompiler.struct.StructClass; | ||
| import org.jetbrains.java.decompiler.struct.StructMethod; | ||
| import org.jetbrains.java.decompiler.struct.consts.LinkConstant; | ||
| import org.jetbrains.java.decompiler.util.InterpreterUtil; | ||
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| import java.io.IOException; | ||
| import java.util.Iterator; | ||
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| public class MethodReferenceHelper { | ||
| public static boolean convertToMethodReference(RootStatement root) throws IOException { | ||
| return convertToMethodReferenceRec(root); | ||
| } | ||
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| public static boolean convertToMethodReferenceRec(Statement stat) throws IOException { | ||
| boolean result = false; | ||
| for (Statement subStat : stat.getStats()) { | ||
| result |= convertToMethodReferenceRec(subStat); | ||
| } | ||
| if (stat.getExprents() != null) { | ||
| for (int i = 0; i < stat.getExprents().size(); i++) { | ||
| Exprent exp = stat.getExprents().get(i); | ||
| for (Exprent subExp : exp.getAllExprents(true)) { | ||
| if (convertToMethodReference(stat, i, subExp)) { | ||
| result |= true; | ||
| } | ||
| for (int j = 0; j < stat.getExprents().size(); j++) { | ||
| if (stat.getExprents().get(j) == exp) { | ||
| i = j; | ||
| break; | ||
| } | ||
| } | ||
| if (removeInstanceAssignment(stat, i, subExp)) { | ||
| result |= true; | ||
| } | ||
| for (int j = 0; j < stat.getExprents().size(); j++) { | ||
| if (stat.getExprents().get(j) == exp) { | ||
| i = j; | ||
| break; | ||
| } | ||
| } | ||
| } | ||
| } | ||
| } | ||
| return result; | ||
| } | ||
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| private static boolean convertToMethodReference(Statement stat, int i, Exprent exp) throws IOException { | ||
| if (exp instanceof NewExprent newExprent | ||
|
Member
There was a problem hiding this comment. It's probably reasonable to flip this |
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| && newExprent.isLambda() | ||
| && !newExprent.isMethodReference()) { | ||
| if (stat.getTopParent().mt.getName().contains("<init>")) { | ||
| System.out.println(); | ||
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|
||
| } | ||
| String className = newExprent.getNewType().value; | ||
| ClassNode node = DecompilerContext.getClassProcessor().getMapRootClasses().get(className); | ||
| LambdaInformation info = node.lambdaInformation; | ||
| StructClass struct = DecompilerContext.getStructContext().getClass(info.content_class_name); | ||
| StructMethod method = struct.getMethod(info.content_method_key); | ||
| if (!method.hasModifier(CodeConstants.ACC_STATIC)) | ||
| return false; | ||
| method.expandData(struct); | ||
| FullInstructionSequence seq = method.getInstructionSequence(); | ||
| Iterator<Instruction> iterator = seq.iterator(); | ||
| Instruction next = null; | ||
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| int argument = 0; | ||
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| if (!iterator.hasNext()) | ||
| return false; | ||
| next = iterator.next(); | ||
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| // new instance | ||
| if (next.opcode == CodeConstants.opc_new) { | ||
| if (!iterator.hasNext()) | ||
| return false; | ||
| next = iterator.next(); | ||
| if (next.opcode != CodeConstants.opc_dup) | ||
| return false; | ||
|
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||
| if (!iterator.hasNext()) | ||
| return false; | ||
| next = iterator.next(); | ||
| } | ||
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| // Load arguments | ||
| while (iterator.hasNext() | ||
| && next.opcode >= CodeConstants.opc_iload && next.opcode <= CodeConstants.opc_aload | ||
| && next.operand(0) == argument) { | ||
| next = iterator.next(); | ||
| argument++; | ||
| } | ||
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|
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| if (next == null) | ||
|
Member
There was a problem hiding this comment. This should never be true ( |
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| return false; | ||
| boolean varargs = false; | ||
| int varargsCount = 0; | ||
| // varargs array length | ||
| if (next.opcode >= CodeConstants.opc_bipush && next.opcode <= CodeConstants.opc_sipush) { | ||
| varargsCount = next.operand(0); | ||
| varargs = true; | ||
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| // varargs array creation | ||
| if (!iterator.hasNext()) | ||
| return false; | ||
| next = iterator.next(); | ||
| if (next.opcode < CodeConstants.opc_newarray || next.opcode > CodeConstants.opc_anewarray) | ||
| return false; | ||
| for (int j = 0; j < varargsCount; j++) { | ||
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| // duplicate varargs array | ||
| if (!iterator.hasNext()) | ||
| return false; | ||
| next = iterator.next(); | ||
| if (next.opcode != CodeConstants.opc_dup) | ||
| return false; | ||
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| // varargs array index | ||
| if (!iterator.hasNext()) | ||
| return false; | ||
| next = iterator.next(); | ||
| if (next.opcode < CodeConstants.opc_bipush || next.opcode > CodeConstants.opc_sipush | ||
| || next.operand(0) != j) | ||
| return false; | ||
|
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| // load argument for varargs array | ||
| if (!iterator.hasNext()) | ||
| return false; | ||
| next = iterator.next(); | ||
| if (next.opcode < CodeConstants.opc_iload || next.opcode > CodeConstants.opc_aload | ||
| || next.operand(0) != argument + j) | ||
| return false; | ||
|
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| // store argument in varargs array | ||
| if (!iterator.hasNext()) | ||
| return false; | ||
| next = iterator.next(); | ||
| if (next.opcode < CodeConstants.opc_iastore || next.opcode > CodeConstants.opc_sastore) | ||
| return false; | ||
| } | ||
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| if (!iterator.hasNext()) | ||
| return false; | ||
| next = iterator.next(); | ||
| } | ||
| // invoke method | ||
| if (next.opcode < CodeConstants.opc_invokevirtual || next.opcode > CodeConstants.opc_invokeinterface) | ||
| return false; | ||
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| Instruction invoke = next; | ||
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| if (!iterator.hasNext()) | ||
| return false; | ||
| next = iterator.next(); | ||
|
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| if (next.opcode == CodeConstants.opc_pop) { | ||
| if (!iterator.hasNext()) | ||
| return false; | ||
| next = iterator.next(); | ||
| } | ||
|
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||
| // return | ||
| if (next.opcode < CodeConstants.opc_ireturn || next.opcode > CodeConstants.opc_return) | ||
| return false; | ||
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| if (iterator.hasNext()) | ||
| return false; | ||
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| LinkConstant link = struct.getPool().getLinkConstant(invoke.operand(0)); | ||
| boolean instance = invoke.opcode != CodeConstants.opc_invokestatic | ||
| && !link.elementname.equals(CodeConstants.INIT_NAME); | ||
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| String newClass = link.classname; | ||
| String newMethod = link.elementname; | ||
| String newDescriptor = link.descriptor; | ||
| String newKey = InterpreterUtil.makeUniqueKey(newMethod, newDescriptor); | ||
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| StructClass newStructClass = DecompilerContext.getStructContext().getClass(newClass); | ||
| if (newStructClass == null) | ||
| return false; | ||
| StructMethod newStructMethod = newStructClass.getMethodRecursive(newMethod, newDescriptor); | ||
| if (newStructMethod == null) | ||
| return false; | ||
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| if (newStructMethod.hasModifier(CodeConstants.ACC_SYNTHETIC)) | ||
| return false; | ||
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| ClassNode newNode = DecompilerContext.getClassProcessor().getMapRootClasses().get(newClass); | ||
| if (newNode != null && newNode.type == ClassesProcessor.ClassNode.Type.ANONYMOUS) | ||
| return false; | ||
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| if (method.methodDescriptor().params.length - (varargs ? varargsCount - 1 : 0) != newStructMethod.methodDescriptor().params.length + (instance ? 1 : 0)) | ||
| return false; | ||
| if (newExprent.getConstructor().getLstParameters().size() > (instance ? 1 : 0)) | ||
| return false; | ||
| info.content_class_name = newClass; | ||
| info.content_method_name = newMethod; | ||
| info.content_method_descriptor = newDescriptor; | ||
| info.content_method_invocation_type = switch (invoke.opcode) { | ||
| case CodeConstants.opc_invokevirtual -> CodeConstants.CONSTANT_MethodHandle_REF_invokeVirtual; | ||
| case CodeConstants.opc_invokespecial -> instance ? CodeConstants.CONSTANT_MethodHandle_REF_newInvokeSpecial : CodeConstants.CONSTANT_MethodHandle_REF_invokeSpecial; | ||
| case CodeConstants.opc_invokestatic -> CodeConstants.CONSTANT_MethodHandle_REF_invokeStatic; | ||
| case CodeConstants.opc_invokeinterface -> CodeConstants.CONSTANT_MethodHandle_REF_invokeInterface; | ||
| default -> -1; | ||
| }; | ||
| info.content_method_key = newKey; | ||
| info.is_method_reference = true; | ||
| info.is_content_method_static = invoke.opcode == CodeConstants.opc_invokestatic; | ||
| newExprent.setMethodReference(true); | ||
| InvocationExprent constructor = newExprent.getConstructor(); | ||
| if (instance && constructor.getLstParameters().size() == 1) { | ||
| constructor.setInstance(constructor.getLstParameters().get(0)); | ||
| } | ||
|
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| if (i > 0) { | ||
| Exprent instanceExp = newExprent.getConstructor().getInstance(); | ||
| Exprent previous = stat.getExprents().get(i - 1); | ||
| if (instanceExp instanceof VarExprent varExp | ||
| && previous instanceof AssignmentExprent assignment | ||
| && varExp.equalsVersions(assignment.getLeft()) | ||
| && !varExp.isVarReferenced(stat.getTopParent(), (VarExprent) assignment.getLeft())) { | ||
| newExprent.getConstructor().setInstance(assignment.getRight()); | ||
| newExprent.getConstructor().getLstParameters().set(0, assignment.getRight()); | ||
| stat.getExprents().remove(i - 1); | ||
| } | ||
| } | ||
| return true; | ||
| } | ||
| return false; | ||
| } | ||
|
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| private static boolean removeInstanceAssignment(Statement stat, int i, Exprent exp) { | ||
| if (exp instanceof NewExprent newExp | ||
| && newExp.isLambda() | ||
| && newExp.isMethodReference() | ||
| && i >= 2 | ||
| && newExp.getConstructor().getInstance() instanceof VarExprent stackVar | ||
| && stackVar.isStack()) { | ||
| Exprent nonNull = stat.getExprents().get(i - 1); | ||
| Exprent assign = stat.getExprents().get(i - 2); | ||
| if (nonNull instanceof InvocationExprent inv | ||
| && inv.getClassname().equals("java/util/Objects") | ||
| && inv.getName().equals("requireNonNull") | ||
| && inv.getStringDescriptor().equals("(Ljava/lang/Object;)Ljava/lang/Object;") | ||
| && stackVar.equalsVersions(inv.getLstParameters().get(0)) | ||
| && assign instanceof AssignmentExprent stackAssign | ||
| && stackVar.equalsVersions(stackAssign.getLeft())) { | ||
| newExp.getConstructor().setInstance(stackAssign.getRight()); | ||
| newExp.getConstructor().getLstParameters().set(0, stackAssign.getRight()); | ||
| stat.getExprents().remove(i - 1); | ||
| stat.getExprents().remove(i - 2); | ||
| return true; | ||
| } | ||
| } | ||
| return false; | ||
| } | ||
| } | ||
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This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
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This appears to also modify existing lambdas which could be represented with a method reference. Perhaps it should be behind a decompiler option