SourceStateAttachmentPass.cpp

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/* src/vm/jit/compiler2/SourceStateAttachmentPass.cpp - SourceStateAttachmentPass

   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.

*/

#include <algorithm>

#include "vm/jit/compiler2/SourceStateAttachmentPass.hpp"
#include "vm/jit/compiler2/PassManager.hpp"
#include "vm/jit/compiler2/JITData.hpp"
#include "vm/jit/compiler2/PassUsage.hpp"
#include "vm/jit/compiler2/MethodC2.hpp"
#include "vm/jit/compiler2/InstructionMetaPass.hpp"
#include "vm/jit/compiler2/ListSchedulingPass.hpp"
#include "vm/jit/compiler2/MachineInstructionSchedulingPass.hpp"
#include "vm/jit/compiler2/ScheduleClickPass.hpp"
#include "vm/jit/compiler2/GlobalSchedule.hpp"
#include "vm/jit/compiler2/Instructions.hpp"
#include "vm/jit/compiler2/alloc/queue.hpp"
#include "vm/jit/compiler2/alloc/unordered_set.hpp"

#include "toolbox/logging.hpp"

// define name for debugging (see logging.hpp)
#define DEBUG_NAME "compiler2/SourceStateAttachment"

namespace cacao {
namespace jit {
namespace compiler2 {

namespace {

SourceStateInst *get_associated_source_state(Instruction *I) {
    for (auto i = I->rdep_begin(); i != I->rdep_end(); i++) {
        SourceStateInst *source_state = (*i)->to_SourceStateInst();
        if (source_state != NULL) {
            return source_state;
        }
    }
    return NULL;
}

} // end anonymous namespace

SourceStateInst *SourceStateAttachmentPass::process_block(BeginInst *begin,
        SourceStateInst *latest_source_state) {

    assert(begin);

    // This is a CFG merge, therefore it has its own SourceStateInst.
    if (begin->pred_size() > 1) {
        latest_source_state = get_associated_source_state(begin);
    }

    assert(latest_source_state);

    for (auto i = IS->inst_begin(begin); i != IS->inst_end(begin); i++) {
        Instruction *I = *i;

        // Attach the SourceStateInst in case the current Instruction needs one.
        if (I->to_SourceStateAwareInst() && I->to_SourceStateAwareInst()->needs_source_state()) {
            SourceStateAwareInst *sink = I->to_SourceStateAwareInst();
            LOG("Attach " << latest_source_state << " to " << sink->to_Instruction() << nl);
            sink->set_source_state(latest_source_state);
        }

        // Keep track of the latest applicable SourceStateInst.
        if (I->has_side_effects()) {
            latest_source_state = get_associated_source_state(I);
            assert(latest_source_state);
        }
    }

    return latest_source_state;
}

bool SourceStateAttachmentPass::run(JITData &JD) {
    M = JD.get_Method();
    IS = get_Pass<ListSchedulingPass>();

    // The blocks that have not yet been processed.
    alloc::queue<BeginInst*>::type blocks_to_process;

    // For each block in blocks_to_process this holds the corresponding
    // SourceStateInst that is applicable at the entry of the block.
    alloc::queue<SourceStateInst*>::type source_state_at_block_entry;

    // The blocks that have already been processed.
    alloc::unordered_set<BeginInst*>::type processed_blocks;

    BeginInst *init_bb = M->get_init_bb();
    SourceStateInst *init_source_state = get_associated_source_state(init_bb);

    blocks_to_process.push(init_bb);
    source_state_at_block_entry.push(init_source_state);

    while (!blocks_to_process.empty()) {
        BeginInst *begin = blocks_to_process.front();
        blocks_to_process.pop();
        SourceStateInst *latest_source_state = source_state_at_block_entry.front();
        source_state_at_block_entry.pop();

        // Ignore blocks that have already been processed.
        if (processed_blocks.count(begin) > 0) {
            continue;
        }

        latest_source_state = process_block(begin, latest_source_state);
        processed_blocks.insert(begin);

        EndInst *end = begin->get_EndInst();
        for (auto i = end->succ_begin(); i != end->succ_end(); i++) {
            BeginInst *successor = (*i).get();
            blocks_to_process.push(successor);
            source_state_at_block_entry.push(latest_source_state);
        }
    }

    return true;
}

// pass usage
PassUsage& SourceStateAttachmentPass::get_PassUsage(PassUsage &PU) const {
    PU.add_requires<InstructionMetaPass>();
    PU.add_requires<ListSchedulingPass>();
    PU.add_schedule_before<MachineInstructionSchedulingPass>();
    return PU;
}

// register pass
static PassRegistry<SourceStateAttachmentPass> X("SourceStateAttachmentPass");

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


/*
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 * Please do not remove this and leave it at the end of the file, where
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