SSAConstructionPass.hpp

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

   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_SSACONSTRUCTIONPASS
#define _JIT_COMPILER2_SSACONSTRUCTIONPASS

#include "vm/jit/compiler2/Pass.hpp"
#include "vm/jit/compiler2/Instruction.hpp"
#include "vm/jit/jit.hpp"
#include "vm/jit/compiler2/alloc/unordered_map.hpp"

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

MM_MAKE_NAME(SSAConstructionPass)

namespace cacao {
namespace jit {
namespace compiler2 {

class InVarPhis;

/**
 * SSAConstructionPass
 *
 * This Pass constructs the compiler2 specific SSA based IR from
 * the ICMD_* style IR used in the baseline compiler.
 *
 * The approach is based on "Simple and Efficient Construction of
 * Static Singe Assignment Form" by Braun et al. 2013 @cite SSAsimple2013.
 */
class SSAConstructionPass : public Pass, public memory::ManagerMixin<SSAConstructionPass> {
private:
    Method *M;
    jitdata *jd;
    alloc::vector<BeginInst*>::type BB;
    alloc::unordered_map<BeginInst*,size_t>::type beginToIndex;
    alloc::vector<alloc::vector<Value*>::type >::type current_def;
    // TODO may be changed to std::vector<unordered_map<int,PHIInst*> > incomplete_phi;
    alloc::vector<alloc::vector<PHIInst*>::type >::type incomplete_phi;
    // TODO this should be merged with incomplete_phi
    alloc::vector<alloc::list<InVarPhis*>::type >::type incomplete_in_phi;

    alloc::vector<bool>::type sealed_blocks;
    alloc::vector<bool>::type filled_blocks;

    /// Used to remember which basicblocks have already been visited.
    ///
    /// This vector is indexed by basicblock indices (i.e. by basicblock::nr).
    alloc::vector<bool>::type visited_blocks;

    /// Indicates whether IR construction should be skipped for a basicblock.
    ///
    /// This vector is indexed by basicblock indices (i.e. by basicblock::nr).
    ///
    /// @see SSAConstructionPass::deoptimize()
    alloc::vector<bool>::type skipped_blocks;

    alloc::vector<Type::TypeID>::type var_type_tbl;
    void write_variable(size_t varindex, size_t bb, Value *V);
    Value* read_variable_recursive(size_t varindex, size_t bb);
    Value* add_phi_operands(size_t varindex, PHIInst *phi);
    Value* try_remove_trivial_phi(PHIInst *phi);
    void seal_block(size_t bb);
    bool try_seal_block(basicblock *bb);
    void print_current_def() const;

    /// Check whether all predecessor blocks of @p bb have been skipped.
    ///
    /// @param bb The block to check.
    ///
    /// @return True if all predecessors have been skipped, false otherwise.
    bool skipped_all_predecessors(basicblock *bb);

    /// Remove unreachable BeginInsts and their corresponding EndInsts.
    void remove_unreachable_blocks();

    /// Helper function to terminate a block with a DeoptimizeInst.
    ///
    /// Assigns a new DeoptimizeInst to the BeginInst that corresponds to the
    /// given @p bbindex. Additionally the corresponding skipped_blocks flag
    /// is set to true in order to signal that IR construction should be skipped
    /// for the rest of this block.
    ///
    /// @param bbindex The corresponding basicblock index.
    void deoptimize(int bbindex);

    void install_javalocal_dependencies(SourceStateInst *source_state,
            s4 *javalocals, basicblock *bb);

    void install_stackvar_dependencies(SourceStateInst *source_state,
        s4 *stack, s4 stackdepth, s4 paramcount, basicblock *bb);

    SourceStateInst *record_source_state(Instruction *I, instruction *iptr,
        basicblock *bb, s4 *javalocals, s4 *stack, s4 stackdepth);

    /// Creates a CONSTInst of type @p type from the s2 operand of @p iptr.
    ///
    /// @param iptr The corresponding baseline IR instruction.
    /// @param type The corresponding type.
    ///
    /// @return The new CONSTInst.
    CONSTInst *parse_s2_constant(instruction *iptr, Type::TypeID type);

public:
    Value* read_variable(size_t varindex, size_t bb);
    SSAConstructionPass() : Pass() {}
    virtual bool run(JITData &JD);
    virtual bool verify() const;
    virtual PassUsage& get_PassUsage(PassUsage &PU) const;
};

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

#endif /* _JIT_COMPILER2_SSACONSTRUCTIONPASS */


/*
 * 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.
 * ---------------------------------------------------------------------
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 * mode: c++
 * indent-tabs-mode: t
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