LoopBase.hpp

Go to the documentation of this file.

/* src/vm/jit/compiler2/LoopBase.hpp - LoopBase

   Copyright (C) 2013
   CACAOVM - Verein zur Foerderung der freien virtuellen Maschine CACAO

   This file is part of CACAO.

   This program is free software; you can redistribute it and/or
   modify it under the terms of the GNU General Public License as
   published by the Free Software Foundation; either version 2, or (at
   your option) any later version.

   This program is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
   02110-1301, USA.

*/

#ifndef _JIT_COMPILER2_LOOPBASE
#define _JIT_COMPILER2_LOOPBASE

#include <cstddef> // for NULL
#include "vm/jit/compiler2/alloc/unordered_set.hpp"

#include "vm/jit/compiler2/alloc/set.hpp"
#include "vm/jit/compiler2/alloc/map.hpp"
#include "vm/jit/compiler2/alloc/vector.hpp"

namespace cacao {

// forward declaration
class OStream;

namespace jit {
namespace compiler2 {

template <class _T>
class LoopBase {
public:
    typedef _T NodeType;
    typedef typename alloc::unordered_set<LoopBase*>::type LoopSetTy;
    typedef typename LoopSetTy::iterator loop_iterator;
private:
    NodeType *header;
    NodeType *exit;
    LoopBase      *parent;
    LoopSetTy inner_loops;
public:
    LoopBase(NodeType *header, NodeType *exit) : header(header), exit(exit), parent(NULL) {}
    NodeType *get_header() const {
        return header;
    }
    NodeType *get_exit() const {
        return exit;
    }
    LoopBase *get_parent() const {
        return parent;
    }
    loop_iterator loop_begin() {
        return inner_loops.begin();
    }
    loop_iterator loop_end() {
        return inner_loops.end();
    }
    void add_inner_loop(LoopBase* inner_loop) {
        if(!inner_loop->parent) {
            inner_loop->parent = this;
            inner_loops.insert(inner_loop);
        }
    }
    void set_parent(LoopBase* outer_loop) {
        if (outer_loop) {
            outer_loop->add_inner_loop(this);
        }
    }
};

template <class _T>
class LoopTreeBase {
public:
    typedef _T NodeType;
    typedef LoopBase<NodeType> LoopType;
    // Note vector needed for std::sort!
    typedef typename LoopType::LoopSetTy LoopSetTy;
    typedef typename LoopSetTy::iterator loop_iterator;
    typedef typename LoopSetTy::const_iterator const_loop_iterator;
    typedef std::pair<const_loop_iterator, const_loop_iterator> ConstLoopIteratorPair;

    typedef typename alloc::vector<LoopType*>::type LoopListTy;
    typedef typename LoopListTy::iterator iterator;
    typedef typename LoopListTy::reverse_iterator reverse_iterator;
protected:
    bool reducible;
    LoopListTy loops;
    LoopSetTy top_loops;
    typename alloc::map<NodeType*,LoopType*>::type loop_map;
    typename alloc::map<NodeType*,LoopSetTy>::type loop_header_map;

    void set_loop(NodeType* node, LoopType* loop) {
        loop_map[node] = loop;
    }
    void insert_loop_header(NodeType* node, LoopType* loop) {
        loop_header_map[node].insert(loop);
    }
    iterator begin() {
        return loops.begin();
    }
    iterator end() {
        return loops.end();
    }
    reverse_iterator rbegin() {
        return loops.rbegin();
    }
    reverse_iterator rend() {
        return loops.rend();
    }
public:
    LoopTreeBase() : reducible(true) {}

    bool is_reducible() const {
        return reducible;
    }
    LoopType *add_loop(NodeType* header, NodeType *exit) {
        LoopType *loop =new LoopType(header,exit);
        loops.push_back(loop);
        return loop;
    }
    void add_top_loop(LoopType* loop) {
        if(loop) {
            top_loops.insert(loop);
        }
    }
    loop_iterator loop_begin() {
        return top_loops.begin();
    }
    loop_iterator loop_end() {
        return top_loops.end();
    }
    /**
     * Get the inner most loop which contains BI or NULL if not contained in any loop
     */
    LoopType* get_Loop(NodeType *BI) const {
        typename alloc::map<NodeType*,LoopType*>::type::const_iterator it = loop_map.find(BI);
        if (it == loop_map.end()) {
            return NULL;
        }
        return it->second;
    }
    bool is_loop_header(NodeType *BI) const {
        typename alloc::map<NodeType*,LoopSetTy>::type::const_iterator it = loop_header_map.find(BI);
        if (it == loop_header_map.end()) {
            return false;
        }
        return true;
    }
    ConstLoopIteratorPair get_Loops_from_header(NodeType *BI) const {
        typename alloc::map<NodeType*,LoopSetTy>::type::const_iterator it = loop_header_map.find(BI);
        if (it == loop_header_map.end()) {
            // TODO there must be a better approach...
            static LoopSetTy empty;
            return std::make_pair(empty.begin(),empty.end());
        }
        return std::make_pair(it->second.begin(),it->second.end());
    }
    bool is_backedge(NodeType *src, NodeType *header) const {
        for (ConstLoopIteratorPair it = get_Loops_from_header(header);
                it.first != it.second; ++it.first) {
            LoopType *loop = *it.first;
            if(loop->get_exit() == src) {
                return true;
            }
        }

        return false;
    }
    /**
     * Test if a loop is a strictly inner loop of another loop.
     *
     * Note that a loop is not an inner loop of itself!
     */
    bool is_inner_loop(LoopType *inner, LoopType *outer) const {
        if (!inner || inner == outer) {
            return false;
        }
        if (!outer) {
            // every loop is a inner loop of no loop
            return true;
        }
        while((inner = inner->get_parent())) {
            if (inner == outer) {
                return true;
            }
        }
        return false;
    }
    /**
     * TODO: cache?
     */
    int loop_nest(LoopType *loop) const {
        if(!loop)
            return -1;
        unsigned nest = 0;
        while((loop = loop->get_parent())) {
            ++nest;
        }
        return nest;
    }
    virtual ~LoopTreeBase() {
        for (typename LoopListTy::iterator i = loops.begin(), e = loops.end();
                i != e; ++i) {
            delete *i;
        }
    }

};

} // end namespace compiler2
} // end namespace jit
} // end namespace cacao

#endif /* _JIT_COMPILER2_LOOPBASE */


/*
 * These are local overrides for various environment variables in Emacs.
 * Please do not remove this and leave it at the end of the file, where
 * Emacs will automagically detect them.
 * ---------------------------------------------------------------------
 * Local variables:
 * mode: c++
 * indent-tabs-mode: t
 * c-basic-offset: 4
 * tab-width: 4
 * End:
 * vim:noexpandtab:sw=4:ts=4:
 */