/*

Copyright (C) 2012-2017 Max Brister

This file is part of Octave.

Octave 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 3 of the License, or
(at your option) any later version.

Octave 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 Octave; see the file COPYING.  If not, see
<http://www.gnu.org/licenses/>.

*/

// Author: Max Brister <max@2bass.com>

#if ! defined (octave_pt_jit_h)
#define octave_pt_jit_h 1

#include "octave-config.h"

#if defined (HAVE_LLVM)

#include "jit-ir.h"
#include "pt-walk.h"
#include "symtab.h"

// octave_value_list is not (yet) in the octave namespace
class octave_value_list;

namespace octave
{
  // Convert from the parse tree (AST) to the low level Octave IR.
  class
  jit_convert : public tree_walker
  {
  public:
    typedef std::pair<jit_type *, std::string> type_bound;
    typedef std::vector<type_bound> type_bound_vector;
    typedef std::map<std::string, jit_variable *> variable_map;

    jit_convert (tree& tee, jit_type *for_bounds = nullptr);

    jit_convert (octave_user_function& fcn, const std::vector<jit_type *>& args);

    template <typename ...Args>
    jit_call * create_checked (const Args&... args)
    {
      jit_call *ret = factory.create<jit_call> (args...);
      return create_checked_impl (ret);
    }

    jit_block_list& get_blocks (void) { return blocks; }

    const type_bound_vector& get_bounds (void) const { return bounds; }

    jit_factory& get_factory (void) { return factory; }

    llvm::Function *get_function (void) const { return function; }

    const variable_map& get_variable_map (void) const { return vmap; }

    void visit_anon_fcn_handle (tree_anon_fcn_handle&);

    void visit_argument_list (tree_argument_list&);

    void visit_binary_expression (tree_binary_expression&);

    void visit_boolean_expression (tree_boolean_expression&);

    void visit_break_command (tree_break_command&);

    void visit_colon_expression (tree_colon_expression&);

    void visit_continue_command (tree_continue_command&);

    void visit_decl_command (tree_decl_command&);

    void visit_decl_init_list (tree_decl_init_list&);

    void visit_decl_elt (tree_decl_elt&);

    void visit_simple_for_command (tree_simple_for_command&);

    void visit_complex_for_command (tree_complex_for_command&);

    void visit_octave_user_script (octave_user_script&);

    void visit_octave_user_function (octave_user_function&);

    void visit_octave_user_function_header (octave_user_function&);

    void visit_octave_user_function_trailer (octave_user_function&);

    void visit_function_def (tree_function_def&);

    void visit_identifier (tree_identifier&);

    void visit_if_clause (tree_if_clause&);

    void visit_if_command (tree_if_command&);

    void visit_if_command_list (tree_if_command_list&);

    void visit_index_expression (tree_index_expression&);

    void visit_matrix (tree_matrix&);

    void visit_cell (tree_cell&);

    void visit_multi_assignment (tree_multi_assignment&);

    void visit_no_op_command (tree_no_op_command&);

    void visit_constant (tree_constant&);

    void visit_fcn_handle (tree_fcn_handle&);

    void visit_funcall (tree_funcall&);

    void visit_parameter_list (tree_parameter_list&);

    void visit_postfix_expression (tree_postfix_expression&);

    void visit_prefix_expression (tree_prefix_expression&);

    void visit_return_command (tree_return_command&);

    void visit_return_list (tree_return_list&);

    void visit_simple_assignment (tree_simple_assignment&);

    void visit_statement (tree_statement&);

    void visit_statement_list (tree_statement_list&);

    void visit_switch_case (tree_switch_case&);

    void visit_switch_case_list (tree_switch_case_list&);

    void visit_switch_command (tree_switch_command&);

    void visit_try_catch_command (tree_try_catch_command&);

    void visit_unwind_protect_command (tree_unwind_protect_command&);

    void visit_while_command (tree_while_command&);

    void visit_do_until_command (tree_do_until_command&);
  private:
    std::vector<std::pair<std::string, bool>> arguments;
    type_bound_vector bounds;

    bool converting_function;

    // the scope of the function we are converting, or the current scope
    symbol_table::scope *scope;

    jit_factory factory;

    // used instead of return values from visit_* functions
    jit_value *result;

    jit_block *entry_block;

    jit_block *final_block;

    jit_block *block;

    llvm::Function *function;

    jit_block_list blocks;

    std::vector<jit_magic_end::context> end_context;

    size_t iterator_count;
    size_t for_bounds_count;
    size_t short_count;

    variable_map vmap;

    void initialize (symbol_table::scope *s);

    jit_call * create_checked_impl (jit_call *ret);

    // get an existing vairable.  If the variable does not exist, it will not be
    // created
    jit_variable * find_variable (const std::string& vname) const;

    // get a variable, create it if it does not exist.  The type will default to
    // the variable's current type in the symbol table.
    jit_variable * get_variable (const std::string& vname);

    // create a variable of the given name and given type.  Will also insert an
    // extract statement
    jit_variable * create_variable (const std::string& vname, jit_type *type,
                                    bool isarg = true);

    // The name of the next for loop iterator.  If inc is false, then the
    // iterator counter will not be incremented.
    std::string next_iterator (bool inc = true)
    { return next_name ("#iter", iterator_count, inc); }

    std::string next_for_bounds (bool inc = true)
    { return next_name ("#for_bounds", for_bounds_count, inc); }

    std::string next_shortcircut_result (bool inc = true)
    { return next_name ("#shortcircut_result", short_count, inc); }

    std::string next_name (const char *prefix, size_t& count, bool inc);

    jit_instruction * resolve (tree_index_expression& exp,
                               jit_value *extra_arg = nullptr, bool lhs = false);

    jit_value * do_assign (tree_expression *exp, jit_value *rhs,
                           bool artificial = false);

    jit_value * do_assign (const std::string& lhs, jit_value *rhs, bool print,
                           bool artificial = false);

    jit_value * visit (tree *tee) { return visit (*tee); }

    jit_value * visit (tree& tee);

    typedef std::list<jit_block *> block_list;
    block_list breaks;
    block_list continues;

    void finish_breaks (jit_block *dest, const block_list& lst);
  };

  // Convert from the low level Octave IR to LLVM
  class
  jit_convert_llvm : public jit_ir_walker
  {
  public:
    llvm::Function * convert_loop (llvm::Module *module,
                                   const jit_block_list& blocks,
                                   const std::list<jit_value *>& constants);

    jit_function convert_function (llvm::Module *module,
                                   const jit_block_list& blocks,
                                   const std::list<jit_value *>& constants,
                                   octave_user_function& fcn,
                                   const std::vector<jit_type *>& args);

    // arguments to the llvm::Function for loops
    const std::vector<std::pair<std::string, bool>>& get_arguments(void) const
    { return argument_vec; }

#define JIT_METH(clname)                        \
    virtual void visit (jit_ ## clname&);

    JIT_VISIT_IR_CLASSES;

#undef JIT_METH
  private:
    // name -> argument index (used for compiling functions)
    std::map<std::string, int> argument_index;

    std::vector<std::pair<std::string, bool>> argument_vec;

    // name -> llvm argument (used for compiling loops)
    std::map<std::string, llvm::Value *> arguments;

    bool converting_function;

    // only used if we are converting a function
    jit_function creating;

    llvm::Function *function;
    llvm::BasicBlock *prelude;

    void convert (const jit_block_list& blocks,
                  const std::list<jit_value *>& constants);

    void finish_phi (jit_phi *phi);

    void visit (jit_value *jvalue)
    {
      return visit (*jvalue);
    }

    void visit (jit_value& jvalue)
    {
      jvalue.accept (*this);
    }
  };

  // type inference and SSA construction on the low level Octave IR
  class
  jit_infer
  {
  public:
    typedef jit_convert::variable_map variable_map;

    jit_infer (jit_factory& afactory, jit_block_list& ablocks,
               const variable_map& avmap);

    jit_block_list& get_blocks (void) const { return blocks; }

    jit_factory& get_factory (void) const { return factory; }

    void infer (void);
  private:
    jit_block_list& blocks;
    jit_factory& factory;
    const variable_map& vmap;
    std::list<jit_instruction *> worklist;

    void append_users (jit_value *v);

    void append_users_term (jit_terminator *term);

    void construct_ssa (void);

    void do_construct_ssa (jit_block& block, size_t avisit_count);

    jit_block& entry_block (void) { return *blocks.front (); }

    jit_block& final_block (void) { return *blocks.back (); }

    void place_releases (void);

    void push_worklist (jit_instruction *instr);

    void remove_dead ();

    void release_dead_phi (jit_block& ablock);

    void release_temp (jit_block& ablock, std::set<jit_value *>& temp);

    void simplify_phi (void);

    void simplify_phi (jit_phi& phi);
  };

  class
  tree_jit
  {
  public:
    ~tree_jit (void);

    static bool execute (tree_simple_for_command& cmd,
                         const octave_value& bounds);

    static bool execute (tree_while_command& cmd);

    static bool execute (octave_user_function& fcn, const octave_value_list& args,
                         octave_value_list& retval);

    llvm::ExecutionEngine * get_engine (void) const { return engine; }

    llvm::Module * get_module (void) const { return module; }

    void optimize (llvm::Function *fn);
  private:
    tree_jit (void);

    static tree_jit& instance (void);

    bool initialize (void);

    bool do_execute (tree_simple_for_command& cmd, const octave_value& bounds);

    bool do_execute (tree_while_command& cmd);

    bool do_execute (octave_user_function& fcn, const octave_value_list& args,
                     octave_value_list& retval);

    bool enabled (void);

    size_t trip_count (const octave_value& bounds) const;

    llvm::Module *module;
#if defined (LEGACY_PASSMANAGER)
    llvm::legacy::PassManager *module_pass_manager;
    llvm::legacy::FunctionPassManager *pass_manager;
#else
    llvm::PassManager *module_pass_manager;
    llvm::FunctionPassManager *pass_manager;
#endif
    llvm::ExecutionEngine *engine;
  };

  class
  jit_function_info
  {
  public:
    jit_function_info (tree_jit& tjit, octave_user_function& fcn,
                       const octave_value_list& ov_args);

    bool execute (const octave_value_list& ov_args,
                  octave_value_list& retval) const;

    bool match (const octave_value_list& ov_args) const;
  private:
    typedef octave_base_value *(*jited_function)(octave_base_value**);

    std::vector<jit_type *> argument_types;
    jited_function function;
  };

  class
  jit_info
  {
  public:
    // we use a pointer here so we don't have to include ov.h
    typedef std::map<std::string, const octave_value *> vmap;

    jit_info (tree_jit& tjit, tree& tee);

    jit_info (tree_jit& tjit, tree& tee, const octave_value& for_bounds);

    ~jit_info (void);

    bool execute (const vmap& extra_vars = vmap ()) const;

    bool match (const vmap& extra_vars = vmap ()) const;
  private:
    typedef jit_convert::type_bound type_bound;
    typedef jit_convert::type_bound_vector type_bound_vector;
    typedef void (*jited_function)(octave_base_value**);

    void compile (tree_jit& tjit, tree& tee, jit_type *for_bounds = nullptr);

    octave_value find (const vmap& extra_vars, const std::string& vname) const;

    llvm::ExecutionEngine *engine;
    jited_function function;
    llvm::Function *llvm_function;

    std::vector<std::pair<std::string, bool>> arguments;
    type_bound_vector bounds;
  };

}

#endif
#endif