org.neo4j.codegen.bytecode.ByteCodeMethodWriter Maven / Gradle / Ivy
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Simple library for generating code.
/*
* Copyright (c) "Neo4j"
* Neo4j Sweden AB [https://neo4j.com]
*
* This file is part of Neo4j.
*
* Neo4j is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see stateStack = new LinkedList<>();
ByteCodeMethodWriter(ClassVisitor classVisitor, MethodDeclaration declaration, TypeReference ignore) {
this.declaration = declaration;
for (Parameter parameter : declaration.parameters()) {
TypeReference type = parameter.type();
if (type.isInnerClass() && !type.isArray()) {
classVisitor.visitInnerClass(byteCodeName(type), outerName(type), type.simpleName(), type.modifiers());
}
}
int access = declaration.isStatic() ? ACC_PUBLIC + ACC_STATIC : ACC_PUBLIC;
this.methodVisitor = classVisitor.visitMethod(
access, declaration.name(), desc(declaration), signature(declaration), exceptions(declaration));
this.methodVisitor.visitCode();
this.expressionVisitor = new ByteCodeExpressionVisitor(this.methodVisitor);
stateStack.push(new Method(methodVisitor, declaration.returnType().isVoid()));
}
@Override
public boolean isStatic() {
return declaration.isStatic();
}
@Override
public void done() {
methodVisitor.visitEnd();
}
@Override
public void expression(Expression expression) {
expression.accept(expressionVisitor);
}
@Override
public void put(Expression target, FieldReference field, Expression value) {
target.accept(expressionVisitor);
value.accept(expressionVisitor);
methodVisitor.visitFieldInsn(PUTFIELD, byteCodeName(field.owner()), field.name(), typeName(field.type()));
}
@Override
public void putStatic(FieldReference field, Expression value) {
value.accept(expressionVisitor);
methodVisitor.visitFieldInsn(PUTSTATIC, byteCodeName(field.owner()), field.name(), typeName(field.type()));
}
@Override
public void returns() {
methodVisitor.visitInsn(RETURN);
}
@Override
public void returns(Expression value) {
value.accept(expressionVisitor);
if (declaration.returnType().isPrimitive()) {
switch (declaration.returnType().name()) {
case "int":
case "byte":
case "short":
case "char":
case "boolean":
methodVisitor.visitInsn(IRETURN);
break;
case "long":
methodVisitor.visitInsn(LRETURN);
break;
case "float":
methodVisitor.visitInsn(FRETURN);
break;
case "double":
methodVisitor.visitInsn(DRETURN);
break;
default:
methodVisitor.visitInsn(ARETURN);
}
} else {
methodVisitor.visitInsn(ARETURN);
}
}
@Override
public void continues() {
for (Block block : stateStack) {
if (block instanceof While) {
((While) block).continueBlock();
return;
}
}
throw new IllegalStateException("Found no block to continue");
}
@Override
public void breaks(String labelName) {
for (Block block : stateStack) {
if (block instanceof While) {
if (((While) block).breakBlock(labelName)) {
return;
}
}
}
throw new IllegalStateException("Found no block to break out of with label " + labelName);
}
@Override
public void assign(LocalVariable variable, Expression value) {
value.accept(expressionVisitor);
if (variable.type().isPrimitive()) {
switch (variable.type().name()) {
case "int":
case "byte":
case "short":
case "char":
case "boolean":
methodVisitor.visitVarInsn(ISTORE, variable.index());
break;
case "long":
methodVisitor.visitVarInsn(LSTORE, variable.index());
break;
case "float":
methodVisitor.visitVarInsn(FSTORE, variable.index());
break;
case "double":
methodVisitor.visitVarInsn(DSTORE, variable.index());
break;
default:
methodVisitor.visitVarInsn(ASTORE, variable.index());
}
} else {
methodVisitor.visitVarInsn(ASTORE, variable.index());
}
}
@Override
public void beginWhile(Expression test, String labelName) {
Label repeat = new Label();
Label done = new Label();
methodVisitor.visitLabel(repeat);
test.accept(new JumpVisitor(expressionVisitor, methodVisitor, done));
stateStack.push(new While(methodVisitor, repeat, done, labelName));
}
@Override
public void beginIf(Expression test) {
Label after = new Label();
test.accept(new JumpVisitor(expressionVisitor, methodVisitor, after));
stateStack.push(new If(methodVisitor, after));
}
@Override
public void ifElseStatement(Expression test, Consumer onTrue, Consumer onFalse, T block) {
Label onFailLabel = new Label();
Label doneLabel = new Label();
test.accept(new JumpVisitor(expressionVisitor, methodVisitor, onFailLabel));
// test true, evaluate and GOTO done
onTrue.accept(block);
methodVisitor.visitJumpInsn(GOTO, doneLabel);
// test false, go to here
methodVisitor.visitLabel(onFailLabel);
onFalse.accept(block);
// goto here when onTrue body is done
methodVisitor.visitLabel(doneLabel);
}
@Override
public void beginBlock() {
stateStack.push(() -> {});
}
@Override
public void endBlock() {
if (stateStack.isEmpty()) {
throw new IllegalStateException("Unbalanced blocks");
}
stateStack.pop().endBlock();
}
@Override
public void beginTry(Parameter exception) {
Label start = new Label();
Label tryBody = new Label();
Label failBody = new Label();
Label after = new Label();
methodVisitor.visitLabel(start);
stateStack.push(new Catch(methodVisitor, failBody, after));
stateStack.push(new Try(methodVisitor, start, tryBody, failBody, after, exception));
}
@Override
public void beginCatch(LocalVariable exception) {
if (stateStack.peek() instanceof Catch c) {
c.beginCatch(exception);
} else {
throw new IllegalStateException("Mismatched try-catch statement");
}
}
@Override
public void throwException(Expression exception) {
exception.accept(expressionVisitor);
methodVisitor.visitInsn(ATHROW);
}
@Override
public void declare(LocalVariable local) {
// declare is a noop bytecode wise
}
@Override
public void assignVariableInScope(LocalVariable local, Expression value) {
// these are equivalent when it comes to bytecode
assign(local, value);
}
}