Example usage for org.objectweb.asm Label Label

List of usage examples for org.objectweb.asm Label Label

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Introduction

In this page you can find the example usage for org.objectweb.asm Label Label.

Prototype

public Label()

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Document

Constructs a new label.

Usage

From source file:com.google.template.soy.jbcsrc.BytecodeUtils.java

License:Apache License

/**
 * Returns an expression that evaluates to {@code left} if left is non null, and evaluates to
 * {@code right} otherwise. /* ww w . j a v  a 2  s.c  o  m*/
 */
static Expression firstNonNull(final Expression left, final Expression right) {
    checkArgument(left.resultType().getSort() == Type.OBJECT);
    checkArgument(right.resultType().getSort() == Type.OBJECT);
    Features features = Features.of();
    if (Expression.areAllCheap(left, right)) {
        features = features.plus(Feature.CHEAP);
    }
    if (right.isNonNullable()) {
        features = features.plus(Feature.NON_NULLABLE);
    }
    return new Expression(left.resultType(), features) {
        @Override
        void doGen(CodeBuilder cb) {
            Label leftIsNonNull = new Label();
            left.gen(cb); // Stack: L
            cb.dup(); // Stack: L, L
            cb.ifNonNull(leftIsNonNull); // Stack: L
            // pop the extra copy of left
            cb.pop(); // Stack:  
            right.gen(cb); // Stack: R
            cb.mark(leftIsNonNull); // At this point the stack has an instance of L or R
        }
    };
}

From source file:com.google.template.soy.jbcsrc.BytecodeUtils.java

License:Apache License

/**
 * Returns an expression that evaluates equivalently to a java ternary expression: 
 * {@code condition ? left : right}/*w  w  w. ja  v  a 2 s.  com*/
 */
static Expression ternary(final Expression condition, final Expression trueBranch,
        final Expression falseBranch) {
    checkArgument(condition.resultType().equals(Type.BOOLEAN_TYPE));
    checkArgument(trueBranch.resultType().getSort() == falseBranch.resultType().getSort());
    Features features = Features.of();
    if (Expression.areAllCheap(condition, trueBranch, falseBranch)) {
        features = features.plus(Feature.CHEAP);
    }
    if (trueBranch.isNonNullable() && falseBranch.isNonNullable()) {
        features = features.plus(Feature.NON_NULLABLE);
    }
    return new Expression(trueBranch.resultType(), features) {
        @Override
        void doGen(CodeBuilder mv) {
            condition.gen(mv);
            Label ifFalse = new Label();
            Label end = new Label();
            mv.visitJumpInsn(Opcodes.IFEQ, ifFalse); // if 0 goto ifFalse
            trueBranch.gen(mv); // eval true branch
            mv.visitJumpInsn(Opcodes.GOTO, end); // jump to the end
            mv.visitLabel(ifFalse);
            falseBranch.gen(mv); // eval false branch
            mv.visitLabel(end);
        }
    };
}

From source file:com.google.template.soy.jbcsrc.BytecodeUtils.java

License:Apache License

private static Expression doShortCircuitingLogicalOperator(
        final ImmutableList<? extends Expression> expressions, final boolean isOrOperator) {
    checkArgument(!expressions.isEmpty());
    for (Expression expr : expressions) {
        expr.checkAssignableTo(Type.BOOLEAN_TYPE);
    }/* w w  w  .ja va2  s.c  om*/
    if (expressions.size() == 1) {
        return expressions.get(0);
    }

    return new Expression(Type.BOOLEAN_TYPE,
            Expression.areAllCheap(expressions) ? Features.of(Feature.CHEAP) : Features.of()) {
        @Override
        void doGen(CodeBuilder adapter) {
            Label end = new Label();
            Label shortCircuit = new Label();
            for (int i = 0; i < expressions.size(); i++) {
                Expression expr = expressions.get(i);
                expr.gen(adapter);
                if (i == expressions.size() - 1) {
                    // if we are the last one, just goto end. Whatever the result of the last expression is
                    // determines the result of the whole expression (when all prior tests fail).
                    adapter.goTo(end);
                } else {
                    adapter.ifZCmp(isOrOperator ? Opcodes.IFNE : Opcodes.IFEQ, shortCircuit);
                }
            }
            adapter.mark(shortCircuit);
            adapter.pushBoolean(isOrOperator); // default for || is true && is false
            adapter.mark(end);
        }
    };
}

From source file:com.google.template.soy.jbcsrc.ControlFlow.java

License:Apache License

/**
 * Returns a statement that encodes the given sequence of {@link IfBlock if blocks} as an 
 * if-elseif-else chain.//  www  . ja v  a 2s.  c o m
 */
static Statement ifElseChain(final List<IfBlock> ifs, final Optional<Statement> elseBlock) {
    checkArgument(!ifs.isEmpty());
    return new Statement() {
        @Override
        void doGen(CodeBuilder adapter) {
            Label end = new Label();
            Label next;
            for (int i = 0; i < ifs.size(); i++) {
                IfBlock curr = ifs.get(i);
                boolean isLastIfBlock = i == ifs.size() - 1;
                if (isLastIfBlock && !elseBlock.isPresent()) {
                    next = end;
                } else {
                    next = new Label();
                }
                curr.condition().gen(adapter);
                adapter.ifZCmp(Opcodes.IFEQ, next);
                curr.block().gen(adapter);
                if (end != next) {
                    adapter.goTo(end);
                }
                adapter.mark(next);
            }
            if (elseBlock.isPresent()) {
                elseBlock.get().gen(adapter);
                adapter.mark(end);
            }
        }
    };
}

From source file:com.google.template.soy.jbcsrc.DetachState.java

License:Apache License

/**
 * Returns a Statement that will conditionally detach if the given {@link AdvisingAppendable} has
 * been {@link AdvisingAppendable#softLimitReached() output limited}.
 *//* ww  w. j  a  v a  2  s  .  c  om*/
Statement detachLimited(AppendableExpression appendable) {
    if (!appendable.supportsSoftLimiting()) {
        return appendable.toStatement();
    }
    final Label reattachPoint = new Label();
    final SaveRestoreState saveRestoreState = variables.saveRestoreState();

    Statement restore = saveRestoreState.restore();
    int state = addState(reattachPoint, restore);
    final Expression isSoftLimited = appendable.softLimitReached();
    final Statement returnLimited = returnExpression(MethodRef.RENDER_RESULT_LIMITED.invoke());
    final Statement saveState = stateField.putInstanceField(thisExpr, BytecodeUtils.constant(state));
    return new Statement() {
        @Override
        void doGen(CodeBuilder adapter) {
            isSoftLimited.gen(adapter);
            adapter.ifZCmp(Opcodes.IFEQ, reattachPoint); // if !softLimited
            // ok we were limited, save state and return
            saveRestoreState.save().gen(adapter); // save locals
            saveState.gen(adapter); // save the state field
            returnLimited.gen(adapter);
            // Note, the reattach point for 'limited' is _after_ the check.  That means we do not 
            // recheck the limit state.  So if a caller calls us back without freeing any buffer we
            // will print more before checking again.  This is fine, because our caller is breaking the
            // contract.
            adapter.mark(reattachPoint);
        }
    };
}

From source file:com.google.template.soy.jbcsrc.DetachState.java

License:Apache License

/**
 * Generate detach logic for calls.//from ww  w  . j ava 2s. c om
 * 
 * <p>Calls are a little different due to a desire to minimize the cost of detaches. We assume 
 * that if a given call site detaches once, it is more likely to detach multiple times. So we
 * generate code that looks like:   <pre>{@code
 * 
 * RenderResult initialResult = template.render(appendable, renderContext);
 * if (!initialResult.isDone()) {
 *   // save all fields
 *   state = REATTACH_RENDER;
 *   return initialResult;
 * } else {
 *   goto END;
 * }
 * REATTACH_RENDER:
 * // restore nothing!
 * RenderResult secondResult = template.render(appendable, renderContext);
 * if (!secondResult.isDone()) {
 *   // saveFields
 *   state = REATTACH_RENDER;
 *   return secondResult;
 * } else {
 *   // restore all fields
 *   goto END;
 * }
 * END:
 * }</pre>
 * 
 * <p>With this technique we save re-running the save-restore logic for multiple detaches from
 * the same call site.  This should be especially useful for top level templates.
 * 
 * @param callRender an Expression that can generate code to call the render method, should be
 *     safe to generate more than once. 
 */
Statement detachForRender(final Expression callRender) {
    checkArgument(callRender.resultType().equals(RENDER_RESULT_TYPE));
    final Label reattachRender = new Label();
    final SaveRestoreState saveRestoreState = variables.saveRestoreState();
    // We pass NULL statement for the restore logic since we handle that ourselves below
    int state = addState(reattachRender, Statement.NULL_STATEMENT);
    final Statement saveState = stateField.putInstanceField(thisExpr, BytecodeUtils.constant(state));
    return new Statement() {
        @Override
        void doGen(CodeBuilder adapter) {
            // Legend: RR = RenderResult, Z = boolean
            callRender.gen(adapter); // Stack: RR
            adapter.dup(); // Stack: RR, RR
            MethodRef.RENDER_RESULT_IS_DONE.invokeUnchecked(adapter); // Stack: RR, Z
            // if isDone goto Done
            Label end = new Label();
            adapter.ifZCmp(Opcodes.IFNE, end); // Stack: RR

            saveRestoreState.save().gen(adapter);
            saveState.gen(adapter);
            adapter.returnValue();

            adapter.mark(reattachRender);
            callRender.gen(adapter); // Stack: RR
            adapter.dup(); // Stack: RR, RR
            MethodRef.RENDER_RESULT_IS_DONE.invokeUnchecked(adapter); // Stack: RR, Z
            // if isDone goto restore
            Label restore = new Label();
            adapter.ifZCmp(Opcodes.IFNE, restore); // Stack: RR
            // no need to save or restore anything
            adapter.returnValue();
            adapter.mark(restore); // Stack: RR
            saveRestoreState.restore().gen(adapter);
            adapter.mark(end); // Stack: RR
            adapter.pop(); // Stack:
        }
    };
}

From source file:com.google.template.soy.jbcsrc.ExpressionCompiler.java

License:Apache License

/**
 * Compiles the given expression tree to a sequence of bytecode in the current method visitor.
 *
 * <p>The generated bytecode expects that the evaluation stack is empty when this method is
 * called and it will generate code such that the stack contains a single SoyValue when it
 * returns.  The SoyValue object will have a runtime type equal to
 * {@code node.getType().javaType()}.// w w  w  . ja  v a  2  s  . com
 */
SoyExpression compile(ExprNode node) {
    Label reattachPoint = new Label();
    final SoyExpression exec = compile(node, reattachPoint);
    return exec.withSource(exec.labelStart(reattachPoint));
}

From source file:com.google.template.soy.jbcsrc.ExpressionTester.java

License:Apache License

private static ClassData createClass(Class<? extends Invoker> targetInterface, Expression expr) {
    java.lang.reflect.Method invokeMethod;
    try {/* w w w .  java 2 s  .com*/
        invokeMethod = targetInterface.getMethod("invoke");
    } catch (NoSuchMethodException | SecurityException e) {
        throw new RuntimeException(e);
    }
    Class<?> returnType = invokeMethod.getReturnType();
    if (!Type.getType(returnType).equals(expr.resultType())) {
        if (!returnType.equals(Object.class) || expr.resultType().getSort() != Type.OBJECT) {
            throw new IllegalArgumentException(targetInterface + " is not appropriate for this expression");
        }
    }
    TypeInfo generatedType = TypeInfo.create(
            ExpressionTester.class.getPackage().getName() + "." + targetInterface.getSimpleName() + "Impl");
    SoyClassWriter cw = SoyClassWriter.builder(generatedType)
            .setAccess(Opcodes.ACC_FINAL | Opcodes.ACC_SUPER | Opcodes.ACC_PUBLIC)
            .implementing(TypeInfo.create(targetInterface)).build();
    BytecodeUtils.defineDefaultConstructor(cw, generatedType);
    Method invoke = Method.getMethod(invokeMethod);
    Statement.returnExpression(expr).writeMethod(Opcodes.ACC_PUBLIC, invoke, cw);

    Method voidInvoke;
    try {
        voidInvoke = Method.getMethod(Invoker.class.getMethod("voidInvoke"));
    } catch (NoSuchMethodException | SecurityException e) {
        throw new RuntimeException(e); // this method definitely exists
    }
    Statement.concat(LocalVariable.createThisVar(generatedType, new Label(), new Label())
            .invoke(MethodRef.create(invokeMethod)).toStatement(), new Statement() {
                @Override
                void doGen(CodeBuilder adapter) {
                    adapter.visitInsn(Opcodes.RETURN);
                }
            }).writeMethod(Opcodes.ACC_PUBLIC, voidInvoke, cw);
    ClassData data = cw.toClassData();
    checkClassData(data);
    return data;
}

From source file:com.google.template.soy.jbcsrc.MsgCompiler.java

License:Apache License

private void putSelectPartIntoMap(Expression mapExpression, MsgNode originalMsg,
        Map<String, Statement> placeholderNameToPutStatement, SoyMsgSelectPart select) {
    MsgSelectNode repSelectNode = originalMsg.getRepSelectNode(select.getSelectVarName());
    if (!placeholderNameToPutStatement.containsKey(select.getSelectVarName())) {
        Label reattachPoint = new Label();
        Expression value = soyNodeCompiler.compileToString(repSelectNode.getExpr(), reattachPoint);
        placeholderNameToPutStatement.put(select.getSelectVarName(),
                putToMap(mapExpression, select.getSelectVarName(), value).labelStart(reattachPoint));
    }//from   w  w w.  j a v a2s .co m
    // Recursively visit select cases
    for (Case<String> caseOrDefault : select.getCases()) {
        putPlaceholdersIntoMap(mapExpression, originalMsg, caseOrDefault.parts(),
                placeholderNameToPutStatement);
    }
}

From source file:com.google.template.soy.jbcsrc.MsgCompiler.java

License:Apache License

private void putPluralPartIntoMap(Expression mapExpression, MsgNode originalMsg,
        Map<String, Statement> placeholderNameToPutStatement, SoyMsgPluralPart plural) {
    MsgPluralNode repPluralNode = originalMsg.getRepPluralNode(plural.getPluralVarName());
    if (!placeholderNameToPutStatement.containsKey(plural.getPluralVarName())) {
        Label reattachPoint = new Label();
        Expression value = soyNodeCompiler.compileToInt(repPluralNode.getExpr(), reattachPoint);
        placeholderNameToPutStatement.put(plural.getPluralVarName(),
                putToMap(mapExpression, plural.getPluralVarName(), value).labelStart(reattachPoint));
    }//ww w  .j a  v  a 2s .  com
    // Recursively visit plural cases
    for (Case<SoyMsgPluralCaseSpec> caseOrDefault : plural.getCases()) {
        putPlaceholdersIntoMap(mapExpression, originalMsg, caseOrDefault.parts(),
                placeholderNameToPutStatement);
    }
}