Java Code Examples for org.apache.bcel.Constants#IRETURN

The following examples show how to use org.apache.bcel.Constants#IRETURN . These examples are extracted from open source projects. You can vote up the ones you like or vote down the ones you don't like, and go to the original project or source file by following the links above each example. You may check out the related API usage on the sidebar.
Example 1
Source Project: ApkToolPlus   File: ReturnInstruction.java    License: Apache License 2.0 5 votes vote down vote up
public Type getType() {
  switch(opcode) {
    case Constants.IRETURN: return Type.INT;
    case Constants.LRETURN: return Type.LONG;
    case Constants.FRETURN: return Type.FLOAT;
    case Constants.DRETURN: return Type.DOUBLE;
    case Constants.ARETURN: return Type.OBJECT;
    case Constants.RETURN:  return Type.VOID;
 
  default: // Never reached
    throw new ClassGenException("Unknown type " + opcode);
  }
}
 
Example 2
Source Project: ApkToolPlus   File: MethodGen.java    License: Apache License 2.0 4 votes vote down vote up
/**
 * Computes stack usage of an instruction list by performing control flow
 * analysis.
 * 
 * @return maximum stack depth used by method
 */
public static int getMaxStack(ConstantPoolGen cp, InstructionList il,
		CodeExceptionGen[] et) {
	BranchStack branchTargets = new BranchStack();

	/*
	 * Initially, populate the branch stack with the exception handlers,
	 * because these aren't (necessarily) branched to explicitly. in each
	 * case, the stack will have depth 1, containing the exception object.
	 */
	for (int i = 0; i < et.length; i++) {
		InstructionHandle handler_pc = et[i].getHandlerPC();
		if (handler_pc != null)
			branchTargets.push(handler_pc, 1);
	}

	int stackDepth = 0, maxStackDepth = 0;
	InstructionHandle ih = il.getStart();

	while (ih != null) {
		Instruction instruction = ih.getInstruction();
		short opcode = instruction.getOpcode();
		int delta = instruction.produceStack(cp)
				- instruction.consumeStack(cp);

		stackDepth += delta;
		if (stackDepth > maxStackDepth)
			maxStackDepth = stackDepth;

		// choose the next instruction based on whether current is a branch.
		if (instruction instanceof BranchInstruction) {
			BranchInstruction branch = (BranchInstruction) instruction;
			if (instruction instanceof Select) {
				// explore all of the select's targets. the default target
				// is handled
				// below.
				Select select = (Select) branch;
				InstructionHandle[] targets = select.getTargets();
				for (int i = 0; i < targets.length; i++)
					branchTargets.push(targets[i], stackDepth);
				// nothing to fall through to.
				ih = null;
			} else if (!(branch instanceof IfInstruction)) {
				// if an instruction that comes back to following PC,
				// push next instruction, with stack depth reduced by 1.
				if (opcode == Constants.JSR || opcode == Constants.JSR_W)
					branchTargets.push(ih.getNext(), stackDepth - 1);
				ih = null;
			}
			// for all branches, the target of the branch is pushed on the
			// branch stack.
			// conditional branches have a fall through case, selects don't,
			// and
			// jsr/jsr_w return to the next instruction.
			branchTargets.push(branch.getTarget(), stackDepth);
		} else {
			// check for instructions that terminate the method.
			if (opcode == Constants.ATHROW
					|| opcode == Constants.RET
					|| (opcode >= Constants.IRETURN && opcode <= Constants.RETURN))
				ih = null;
		}
		// normal case, go to the next instruction.
		if (ih != null)
			ih = ih.getNext();
		// if we have no more instructions, see if there are any deferred
		// branches to explore.
		if (ih == null) {
			BranchTarget bt = branchTargets.pop();
			if (bt != null) {
				ih = bt.target;
				stackDepth = bt.stackDepth;
			}
		}
	}

	return maxStackDepth;
}