Examples with BlockRecorder org.codehaus.groovy.classgen.asm.CompileStack.BlockRecorder used on opensource projects

Example 6 with BlockRecorder

use of org.codehaus.groovy.classgen.asm.CompileStack.BlockRecorder in project groovy by apache.

the class StatementWriter method writeTryCatchFinally.

public void writeTryCatchFinally(TryCatchStatement statement) {
    controller.getAcg().onLineNumber(statement, "visitTryCatchFinally");
    writeStatementLabel(statement);
    MethodVisitor mv = controller.getMethodVisitor();
    CompileStack compileStack = controller.getCompileStack();
    OperandStack operandStack = controller.getOperandStack();
    Statement tryStatement = statement.getTryStatement();
    final Statement finallyStatement = statement.getFinallyStatement();
    // start try block, label needed for exception table
    Label tryStart = new Label();
    mv.visitLabel(tryStart);
    BlockRecorder tryBlock = makeBlockRecorder(finallyStatement);
    tryBlock.startRange(tryStart);
    tryStatement.visit(controller.getAcg());
    // goto finally part
    Label finallyStart = new Label();
    mv.visitJumpInsn(GOTO, finallyStart);
    Label tryEnd = new Label();
    mv.visitLabel(tryEnd);
    tryBlock.closeRange(tryEnd);
    // pop for "makeBlockRecorder(finallyStatement)"
    controller.getCompileStack().pop();
    BlockRecorder catches = makeBlockRecorder(finallyStatement);
    for (CatchStatement catchStatement : statement.getCatchStatements()) {
        ClassNode exceptionType = catchStatement.getExceptionType();
        String exceptionTypeInternalName = BytecodeHelper.getClassInternalName(exceptionType);
        // start catch block, label needed for exception table
        Label catchStart = new Label();
        mv.visitLabel(catchStart);
        catches.startRange(catchStart);
        // create exception variable and store the exception
        Parameter exceptionVariable = catchStatement.getVariable();
        compileStack.pushState();
        compileStack.defineVariable(exceptionVariable, true);
        // handle catch body
        catchStatement.visit(controller.getAcg());
        // place holder to avoid problems with empty catch blocks
        mv.visitInsn(NOP);
        // pop for the variable
        controller.getCompileStack().pop();
        // end of catch
        Label catchEnd = new Label();
        mv.visitLabel(catchEnd);
        catches.closeRange(catchEnd);
        // goto finally start
        mv.visitJumpInsn(GOTO, finallyStart);
        compileStack.writeExceptionTable(tryBlock, catchStart, exceptionTypeInternalName);
    }
    // Label used to handle exceptions in catches and regularly
    // visited finals.
    Label catchAny = new Label();
    // add "catch any" block to exception table for try part we do this 
    // after the exception blocks, because else this one would supersede
    // any of those otherwise
    compileStack.writeExceptionTable(tryBlock, catchAny, null);
    // same for the catch parts
    compileStack.writeExceptionTable(catches, catchAny, null);
    // pop for "makeBlockRecorder(catches)"
    compileStack.pop();
    // start finally
    mv.visitLabel(finallyStart);
    finallyStatement.visit(controller.getAcg());
    //**
    mv.visitInsn(NOP);
    // goto after all-catching block
    Label skipCatchAll = new Label();
    mv.visitJumpInsn(GOTO, skipCatchAll);
    // start a block catching any Exception
    mv.visitLabel(catchAny);
    //store exception
    //TODO: maybe define a Throwable and use it here instead of Object
    operandStack.push(ClassHelper.OBJECT_TYPE);
    final int anyExceptionIndex = compileStack.defineTemporaryVariable("exception", true);
    finallyStatement.visit(controller.getAcg());
    // load the exception and rethrow it
    mv.visitVarInsn(ALOAD, anyExceptionIndex);
    mv.visitInsn(ATHROW);
    mv.visitLabel(skipCatchAll);
    compileStack.removeVar(anyExceptionIndex);
}