[libfirm] / ir / ir / irgmod.c

/*
 * Copyright (C) 1995-2008 University of Karlsruhe.  All right reserved.
 *
 * This file is part of libFirm.
 *
 * This file may be distributed and/or modified under the terms of the
 * GNU General Public License version 2 as published by the Free Software
 * Foundation and appearing in the file LICENSE.GPL included in the
 * packaging of this file.
 *
 * Licensees holding valid libFirm Professional Edition licenses may use
 * this file in accordance with the libFirm Commercial License.
 * Agreement provided with the Software.
 *
 * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
 * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE.
 */

/**
 * @file
 * @brief    Support for ir graph modification.
 * @author   Martin Trapp, Christian Schaefer, Goetz Lindenmaier
 * @version  $Id$
 */
#include "config.h"

#include "irflag_t.h"
#include "irgwalk.h"
#include "irnode_t.h"
#include "irgraph_t.h"
#include "irgmod.h"
#include "array.h"
#include "ircons.h"
#include "irhooks.h"
#include "iredges_t.h"
#include "irtools.h"
#include "error.h"

/**
 * Turns a node into a "useless" Tuple.  The Tuple just forms a tuple
 * from several inputs.
 * This is useful if a node returning a tuple is removed, but the Projs
 * extracting values from the tuple are not available.
 */
void turn_into_tuple(ir_node *node, int arity)
{
        ir_graph *irg = get_irn_irg(node);
        ir_node **in  = ALLOCAN(ir_node*, arity);
        int       i;

        /* construct a new in array, with every input being bad */
        for (i = 0; i < arity; ++i) {
                in[i] = new_r_Bad(irg);
        }
        set_irn_in(node, arity, in);
        set_irn_op(node, op_Tuple);
}

/**
 * Insert irnode `new' in place of irnode `old'
 * Since `new' may be bigger than `old' replace `old'
 * by an op_Id which is smaller than everything.
 */
void exchange(ir_node *old, ir_node *nw)
{
        ir_graph *irg;

        assert(old && nw);
        assert(old != nw && "Exchanging node with itself is not allowed");

        irg = get_irn_irg(old);
        assert(irg == get_irn_irg(nw) && "New node must be in same irg as old node");

        hook_replace(old, nw);

        /*
         * If new outs are on, we can skip the id node creation and reroute
         * the edges from the old node to the new directly.
         */
        if (edges_activated(irg)) {
                /* copy all dependencies from old to new */
                add_irn_deps(nw, old);

                edges_reroute(old, nw, irg);
                edges_reroute_kind(old, nw, EDGE_KIND_DEP, irg);
                edges_node_deleted(old, irg);
                /* noone is allowed to reference this node anymore */
                set_irn_op(old, op_Deleted);
        } else {
                /* Else, do it the old-fashioned way. */
                ir_node *block;

                hook_turn_into_id(old);

                block = old->in[0];
                if (! block) {
                        block = is_Block(nw) ? nw : get_nodes_block(nw);

                        if (! block) {
                                panic("cannot find legal block for id");
                        }
                }

                if (get_irn_op(old)->opar == oparity_dynamic) {
                        DEL_ARR_F(get_irn_in(old));
                }

                old->op    = op_Id;
                old->in    = NEW_ARR_D (ir_node *, irg->obst, 2);
                old->in[0] = block;
                old->in[1] = nw;
        }
}

/*--------------------------------------------------------------------*/
/*  Functionality for collect_phis                                    */
/*--------------------------------------------------------------------*/

/**
 * Walker: links all Phi nodes to their Blocks lists,
 *         all Proj nodes to there predecessors.
 */
static void collect_phiprojs_walker(ir_node *n, void *env)
{
        ir_node *pred;
        (void) env;

        if (is_Phi(n)) {
                ir_node *block = get_nodes_block(n);
                add_Block_phi(block, n);
        } else if (is_Proj(n)) {
                pred = n;
                do {
                        pred = get_Proj_pred(pred);
                } while (is_Proj(pred));

                set_irn_link(n, get_irn_link(pred));
                set_irn_link(pred, n);
        }
}

void collect_phiprojs(ir_graph *irg)
{
        assert((ir_resources_reserved(irg) & (IR_RESOURCE_IRN_LINK|IR_RESOURCE_PHI_LIST)) ==
                (IR_RESOURCE_IRN_LINK|IR_RESOURCE_PHI_LIST));
        irg_walk_graph(irg, firm_clear_node_and_phi_links, collect_phiprojs_walker, NULL);
}

/*--------------------------------------------------------------------*/
/*  Functionality for part_block                                      */
/*--------------------------------------------------------------------*/

/**
 * Moves node and all predecessors of node from from_bl to to_bl.
 * Does not move predecessors of Phi nodes (or block nodes).
 */
static void move(ir_node *node, ir_node *from_bl, ir_node *to_bl)
{
        int i, arity;

        /* move this node */
        set_nodes_block(node, to_bl);

        /* move its Projs */
        if (get_irn_mode(node) == mode_T) {
                ir_node *proj = get_irn_link(node);
                while (proj) {
                        if (get_nodes_block(proj) == from_bl)
                                set_nodes_block(proj, to_bl);
                        proj = get_irn_link(proj);
                }
        }

        if (is_Phi(node))
                return;

        /* recursion ... */
        arity = get_irn_arity(node);
        for (i = 0; i < arity; i++) {
                ir_node *pred = get_irn_n(node, i);
                if (get_nodes_block(pred) == from_bl)
                        move(pred, from_bl, to_bl);
        }
}

/**
 * Moves node and all predecessors of node from from_bl to to_bl.
 * Does not move predecessors of Phi nodes (or block nodes).
 */
static void move_edges(ir_node *node, ir_node *from_bl, ir_node *to_bl)
{
        int i, arity;

        /* move this node */
        set_nodes_block(node, to_bl);

        /* move its Projs */
        if (get_irn_mode(node) == mode_T) {
                const ir_edge_t *edge;
                foreach_out_edge(node, edge) {
                        ir_node *proj = get_edge_src_irn(edge);
                        set_nodes_block(proj, to_bl);
                }
        }

        /* We must not move predecessors of Phi nodes, even if they are in
         * from_bl. (because these are values from an earlier loop iteration
         * which are not predecessors of node here)
         */
        if (is_Phi(node))
                return;

        /* recursion ... */
        arity = get_irn_arity(node);
        for (i = 0; i < arity; i++) {
                ir_node *pred = get_irn_n(node, i);
                if (get_nodes_block(pred) == from_bl)
                        move_edges(pred, from_bl, to_bl);
        }
}

void part_block(ir_node *node)
{
        ir_node *new_block, *old_block;
        ir_node *phi, *jmp;
        ir_graph *rem = current_ir_graph;

        /* Turn off optimizations so that blocks are not merged again. */
        int rem_opt = get_opt_optimize();
        set_optimize(0);

        current_ir_graph = get_irn_irg(node);

        /* Transform the control flow */
        old_block = get_nodes_block(node);
        new_block = new_Block(get_Block_n_cfgpreds(old_block),
                              get_Block_cfgpred_arr(old_block));

        /* create a jump from new_block to old_block, which is now the lower one */
        jmp = new_r_Jmp(new_block);
        set_irn_in(old_block, 1, &jmp);

        /* move node and its predecessors to new_block */
        move(node, old_block, new_block);

        /* move Phi nodes to new_block */
        phi = get_Block_phis(old_block);
        set_Block_phis(new_block, phi);
        set_Block_phis(old_block, NULL);
        while (phi) {
                set_nodes_block(phi, new_block);
                phi = get_Phi_next(phi);
        }

        set_optimize(rem_opt);
        current_ir_graph = rem;
}

ir_node *part_block_edges(ir_node *node)
{
        ir_graph        *irg       = get_irn_irg(node);
        ir_node         *old_block = get_nodes_block(node);
        ir_node         *new_block = new_r_Block(irg,
                                                 get_Block_n_cfgpreds(old_block),
                                                 get_Block_cfgpred_arr(old_block));
        const ir_edge_t *edge;
        const ir_edge_t *next;

        /* old_block has no predecessors anymore for now */
        set_irn_in(old_block, 0, NULL);

        /* move node and its predecessors to new_block */
        move_edges(node, old_block, new_block);

        /* move Phi nodes to new_block */
        foreach_out_edge_safe(old_block, edge, next) {
                ir_node *phi = get_edge_src_irn(edge);
                if (!is_Phi(phi))
                        continue;
                set_nodes_block(phi, new_block);
        }

        return old_block;
}

void kill_node(ir_node *node)
{
        ir_graph *irg = get_irn_irg(node);
        ir_node *bad = get_irg_bad(irg);
        int i;

        for (i = get_irn_arity(node) - 1; i >= -1; --i) {
                set_irn_n(node, i, bad);
        }
        exchange(node, bad);
}