flowgraph.cpp

#include "flowgraph.h"
#include <map>

namespace Optimize {

FlowGraphNode::FlowGraphNode(int _index, const Asm::Instruction* _instruction,
	IR::VirtualRegister *ignored_register)
	: index(_index), instruction(_instruction)
{
	is_reg_to_reg_assign = instruction->is_reg_to_reg_assign;
	for (int i = 0; i < instruction->outputs.size(); i++)
		assert(instruction->outputs[i]->getIndex() !=
			ignored_register->getIndex());
	for (int i = 0; i < instruction->inputs.size(); i++)
		if ((ignored_register == NULL) ||
				(instruction->inputs[i]->getIndex() !=
				ignored_register->getIndex()))
			used.push_back(instruction->inputs[i]);
		else
			is_reg_to_reg_assign = false;
}

const std::vector< IR::VirtualRegister* >& FlowGraphNode::usedRegisters() const
{
	return used;
}

const std::vector< IR::VirtualRegister* >& FlowGraphNode::assignedRegisters() const
{
	return instruction->outputs;
}

FlowGraph::FlowGraph(const Asm::Instructions &code,
	IR::VirtualRegister *ignored_register)
{
	std::map<std::string, FlowGraphNode *> label_positions;
	nodecount = 0;
	FlowGraphNode *newnode = NULL;
	
	for (Asm::Instructions::const_iterator inst = code.begin();
			inst != code.end(); inst++) {
		nodes.push_back(FlowGraphNode(nodecount, &(*inst), ignored_register));
		if ((*inst).label != NULL)
			label_positions[(*inst).label->getName()] = & nodes.back();;
		nodecount++;
	}
	
	last_instruction = newnode;
	
	for (std::list<FlowGraphNode>::iterator node = nodes.begin();
			node != nodes.end(); node++) {
		FlowGraphNode *current = &(*node);
		for (int i = 0; i < current->instruction->destinations.size(); i++)  {
			const IR::Label *label = current->instruction->destinations[i];
		
			FlowGraphNode *nextnode = NULL;
			if (label == NULL) {
				std::list<FlowGraphNode>::iterator next_iter = node;
				next_iter++;
				if (next_iter != nodes.end())
					nextnode = &(*next_iter);
			} else
				nextnode = label_positions.at(label->getName());
			
			if (nextnode != NULL) {
				current->next.push_back(& *nextnode);
				(*nextnode).previous.push_back(current);
			}
		}
	}
}

}