/*

Copyright (C) 2012 Max Brister <max@2bass.com>

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/>.

*/

#define __STDC_LIMIT_MACROS
#define __STDC_CONSTANT_MACROS

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include "debug.h"
#include "defun.h"
#include "ov.h"
#include "pt-all.h"
#include "pt-jit.h"
#include "sighandlers.h"
#include "symtab.h"
#include "variables.h"

static bool Venable_jit_debugging = false;

static bool Venable_jit_compiler = true;

#ifdef HAVE_LLVM

#include <llvm/Analysis/CallGraph.h>
#include <llvm/Analysis/Passes.h>
#include <llvm/Analysis/Verifier.h>
#include <llvm/Bitcode/ReaderWriter.h>
#include <llvm/LLVMContext.h>
#include <llvm/ExecutionEngine/ExecutionEngine.h>
#include <llvm/ExecutionEngine/JIT.h>
#include <llvm/Module.h>
#include <llvm/PassManager.h>
#include <llvm/Support/IRBuilder.h>
#include <llvm/Support/raw_os_ostream.h>
#include <llvm/Support/TargetSelect.h>
#include <llvm/Target/TargetData.h>
#include <llvm/Transforms/IPO.h>
#include <llvm/Transforms/Scalar.h>

static llvm::IRBuilder<> builder (llvm::getGlobalContext ());

static llvm::LLVMContext& context = llvm::getGlobalContext ();

// -------------------- jit_break_exception --------------------

// jit_break is thrown whenever a branch we are converting has only breaks or
// continues. This is because all code that follows a break or continue is dead.
class jit_break_exception : public std::exception {};

// -------------------- jit_convert --------------------
jit_convert::jit_convert (tree &tee, jit_type *for_bounds)
  : converting_function (false)
{
  initialize (symbol_table::current_scope ());

  if (for_bounds)
    create_variable (next_for_bounds (false), for_bounds);

  try
    {
      visit (tee);
    }
  catch (const jit_break_exception&)
    {}

  // breaks must have been handled by the top level loop
  assert (breaks.empty ());
  assert (continues.empty ());

  block->append (factory.create<jit_branch> (final_block));
  blocks.push_back (final_block);

  for (variable_map::iterator iter = vmap.begin (); iter != vmap.end (); ++iter)
    {
      jit_variable *var = iter->second;
      const std::string& name = var->name ();
      if (name.size () && name[0] != '#')
        final_block->append (factory.create<jit_store_argument> (var));
    }

  final_block->append (factory.create<jit_return> ());
}

jit_convert::jit_convert (octave_user_function& fcn,
                          const std::vector<jit_type *>& args)
  : converting_function (true)
{
  initialize (fcn.scope ());

  tree_parameter_list *plist = fcn.parameter_list ();
  tree_parameter_list *rlist = fcn.return_list ();
  if (plist && plist->takes_varargs ())
    throw jit_fail_exception ("varags not supported");

  if (rlist && (rlist->size () > 1 || rlist->takes_varargs ()))
    throw jit_fail_exception ("multiple returns not supported");

  if (plist)
    {
      tree_parameter_list::iterator piter = plist->begin ();
      for (size_t i = 0; i < args.size (); ++i, ++piter)
        {
          if (piter == plist->end ())
            throw jit_fail_exception ("Too many parameter to function");

          tree_decl_elt *elt = *piter;
          std::string name = elt->name ();
          create_variable (name, args[i]);
        }
    }

  jit_value *return_value = 0;
  bool all_breaking = false;
  if (fcn.is_special_expr ())
    {
      tree_expression *expr = fcn.special_expr ();
      if (expr)
        {
          jit_variable *retvar = get_variable ("#return");
          jit_value *retval;
          try
            {
              retval = visit (expr);
            }
          catch (const jit_break_exception&)
            {}

          if (breaks.size () || continues.size ())
            throw jit_fail_exception ("break/continue not supported in "
                                      "anonymous functions");

          block->append (factory.create<jit_assign> (retvar, retval));
          return_value = retvar;
        }
    }
  else
    {
      try
        {
          visit_statement_list (*fcn.body ());
        }
      catch (const jit_break_exception&)
        {
          all_breaking = true;
        }

      // the user may use break or continue to exit the function
      finish_breaks (final_block, continues);
      finish_breaks (final_block, breaks);
    }

  if (! all_breaking)
    block->append (factory.create<jit_branch> (final_block));

  blocks.push_back (final_block);
  block = final_block;

  if (! return_value && rlist && rlist->size () == 1)
    {
      tree_decl_elt *elt = rlist->front ();
      return_value = get_variable (elt->name ());
    }

  // FIXME: We should use live range analysis to delete variables where needed.
  // For now we just delete everything at the end of the function.
  for (variable_map::iterator iter = vmap.begin (); iter != vmap.end (); ++iter)
    {
      if (iter->second != return_value)
        {
          jit_call *call;
          call = factory.create<jit_call> (&jit_typeinfo::destroy,
                                           iter->second);
          final_block->append (call);
        }
    }

  if (return_value)
    final_block->append (factory.create<jit_return> (return_value));
  else
    final_block->append (factory.create<jit_return> ());
}

void
jit_convert::visit_anon_fcn_handle (tree_anon_fcn_handle&)
{
  throw jit_fail_exception ();
}

void
jit_convert::visit_argument_list (tree_argument_list&)
{
  throw jit_fail_exception ();
}

void
jit_convert::visit_binary_expression (tree_binary_expression& be)
{
  if (be.op_type () >= octave_value::num_binary_ops)
    {
      tree_boolean_expression *boole;
      boole = dynamic_cast<tree_boolean_expression *> (&be);
      assert (boole);
      bool is_and = boole->op_type () == tree_boolean_expression::bool_and;

      std::string short_name = next_shortcircut_result ();
      jit_variable *short_result = factory.create<jit_variable> (short_name);
      vmap[short_name] = short_result;

      jit_block *done = factory.create<jit_block> (block->name ());
      tree_expression *lhs = be.lhs ();
      jit_value *lhsv = visit (lhs);
      lhsv = create_checked (&jit_typeinfo::logically_true, lhsv);

      jit_block *short_early = factory.create<jit_block> ("short_early");
      blocks.push_back (short_early);

      jit_block *short_cont = factory.create<jit_block> ("short_cont");

      if (is_and)
        block->append (factory.create<jit_cond_branch> (lhsv, short_cont, short_early));
      else
        block->append (factory.create<jit_cond_branch> (lhsv, short_early, short_cont));

      block = short_early;

      jit_value *early_result = factory.create<jit_const_bool> (! is_and);
      block->append (factory.create<jit_assign> (short_result, early_result));
      block->append (factory.create<jit_branch> (done));

      blocks.push_back (short_cont);
      block = short_cont;

      tree_expression *rhs = be.rhs ();
      jit_value *rhsv = visit (rhs);
      rhsv = create_checked (&jit_typeinfo::logically_true, rhsv);
      block->append (factory.create<jit_assign> (short_result, rhsv));
      block->append (factory.create<jit_branch> (done));

      blocks.push_back (done);
      block = done;
      result = short_result;
    }
  else
    {
      tree_expression *lhs = be.lhs ();
      jit_value *lhsv = visit (lhs);

      tree_expression *rhs = be.rhs ();
      jit_value *rhsv = visit (rhs);

      const jit_operation& fn = jit_typeinfo::binary_op (be.op_type ());
      result = create_checked (fn, lhsv, rhsv);
    }
}

void
jit_convert::visit_break_command (tree_break_command&)
{
  breaks.push_back (block);
  throw jit_break_exception ();
}

void
jit_convert::visit_colon_expression (tree_colon_expression& expr)
{
  // in the futher we need to add support for classes and deal with rvalues
  jit_value *base = visit (expr.base ());
  jit_value *limit = visit (expr.limit ());
  jit_value *increment;
  tree_expression *tinc = expr.increment ();

  if (tinc)
    increment = visit (tinc);
  else
    increment = factory.create<jit_const_scalar> (1);

  result = block->append (factory.create<jit_call> (jit_typeinfo::make_range, base,
                                            limit, increment));
}

void
jit_convert::visit_continue_command (tree_continue_command&)
{
  continues.push_back (block);
  throw jit_break_exception ();
}

void
jit_convert::visit_global_command (tree_global_command&)
{
  throw jit_fail_exception ();
}

void
jit_convert::visit_persistent_command (tree_persistent_command&)
{
  throw jit_fail_exception ();
}

void
jit_convert::visit_decl_elt (tree_decl_elt&)
{
  throw jit_fail_exception ();
}

void
jit_convert::visit_decl_init_list (tree_decl_init_list&)
{
  throw jit_fail_exception ();
}

void
jit_convert::visit_simple_for_command (tree_simple_for_command& cmd)
{
  // Note we do an initial check to see if the loop will run atleast once.
  // This allows us to get better type inference bounds on variables defined
  // and used only inside the for loop (e.g. the index variable)

  // If we are a nested for loop we need to store the previous breaks
  unwind_protect prot;
  prot.protect_var (breaks);
  prot.protect_var (continues);
  breaks.clear ();
  continues.clear ();

  // we need a variable for our iterator, because it is used in multiple blocks
  std::string iter_name = next_iterator ();
  jit_variable *iterator = factory.create<jit_variable> (iter_name);
  factory.create<jit_variable> (iter_name);
  vmap[iter_name] = iterator;

  jit_block *body = factory.create<jit_block> ("for_body");
  jit_block *tail = factory.create<jit_block> ("for_tail");

  // do control expression, iter init, and condition check in prev_block (block)
  // if we are the top level for loop, the bounds is an input argument.
  jit_value *control = find_variable (next_for_bounds ());
  if (! control)
    control = visit (cmd.control_expr ());
  jit_call *init_iter = factory.create<jit_call> (jit_typeinfo::for_init,
                                                  control);
  block->append (init_iter);
  block->append (factory.create<jit_assign> (iterator, init_iter));

  jit_call *check = factory.create<jit_call> (jit_typeinfo::for_check, control,
                                              iterator);
  block->append (check);
  block->append (factory.create<jit_cond_branch> (check, body, tail));

  blocks.push_back (body);
  block = body;

  // compute the syntactical iterator
  jit_call *idx_rhs = factory.create<jit_call> (jit_typeinfo::for_index,
                                                control, iterator);
  block->append (idx_rhs);
  do_assign (cmd.left_hand_side (), idx_rhs);

  // do loop
  tree_statement_list *pt_body = cmd.body ();
  bool all_breaking = false;
  try
    {
      pt_body->accept (*this);
    }
  catch (const jit_break_exception&)
    {
      if (continues.empty ())
        {
          // WTF are you doing user? Every branch was a break, why did you have
          // a loop??? Users are silly people...
          finish_breaks (tail, breaks);
          blocks.push_back (tail);
          block = tail;
          return;
        }

      all_breaking = true;
    }

  // check our condition, continues jump to this block
  jit_block *check_block = factory.create<jit_block> ("for_check");
  blocks.push_back (check_block);

  jit_block *interrupt_check = factory.create<jit_block> ("for_interrupt");
  blocks.push_back (interrupt_check);

  if (! all_breaking)
    block->append (factory.create<jit_branch> (check_block));
  finish_breaks (check_block, continues);

  block = check_block;
  const jit_operation& add_fn = jit_typeinfo::binary_op (octave_value::op_add);
  jit_value *one = factory.create<jit_const_index> (1);
  jit_call *iter_inc = factory.create<jit_call> (add_fn, iterator, one);
  block->append (iter_inc);
  block->append (factory.create<jit_assign> (iterator, iter_inc));
  check = block->append (factory.create<jit_call> (jit_typeinfo::for_check,
                                                   control, iterator));
  block->append (factory.create<jit_cond_branch> (check, interrupt_check,
                                                  tail));

  block = interrupt_check;
  jit_error_check *ec
    = factory.create<jit_error_check> (jit_error_check::var_interrupt,
                                       body, final_block);
  block->append (ec);

  // breaks will go to our tail
  blocks.push_back (tail);
  finish_breaks (tail, breaks);
  block = tail;
}

void
jit_convert::visit_complex_for_command (tree_complex_for_command&)
{
  throw jit_fail_exception ();
}

void
jit_convert::visit_octave_user_script (octave_user_script&)
{
  throw jit_fail_exception ();
}

void
jit_convert::visit_octave_user_function (octave_user_function&)
{
  throw jit_fail_exception ();
}

void
jit_convert::visit_octave_user_function_header (octave_user_function&)
{
  throw jit_fail_exception ();
}

void
jit_convert::visit_octave_user_function_trailer (octave_user_function&)
{
  throw jit_fail_exception ();
}

void
jit_convert::visit_function_def (tree_function_def&)
{
  throw jit_fail_exception ();
}

void
jit_convert::visit_identifier (tree_identifier& ti)
{
  if (ti.has_magic_end ())
    {
      if (!end_context.size ())
        throw jit_fail_exception ("Illegal end");
      result = block->append (factory.create<jit_magic_end> (end_context));
    }
  else
    {
      jit_variable *var = get_variable (ti.name ());
      jit_instruction *instr;
      instr = factory.create<jit_call> (&jit_typeinfo::grab, var);
      result = block->append (instr);
    }
}

void
jit_convert::visit_if_clause (tree_if_clause&)
{
  throw jit_fail_exception ();
}

void
jit_convert::visit_if_command (tree_if_command& cmd)
{
  tree_if_command_list *lst = cmd.cmd_list ();
  assert (lst); // jwe: Can this be null?
  lst->accept (*this);
}

void
jit_convert::visit_if_command_list (tree_if_command_list& lst)
{
  tree_if_clause *last = lst.back ();
  size_t last_else = static_cast<size_t> (last->is_else_clause ());

  // entry_blocks represents the block you need to enter in order to execute
  // the condition check for the ith clause. For the else, it is simple the
  // else body. If there is no else body, then it is padded with the tail
  std::vector<jit_block *> entry_blocks (lst.size () + 1 - last_else);
  std::vector<jit_block *> branch_blocks (lst.size (), 0); // final blocks
  entry_blocks[0] = block;

  // we need to construct blocks first, because they have jumps to eachother
  tree_if_command_list::iterator iter = lst.begin ();
  ++iter;
  for (size_t i = 1; iter != lst.end (); ++iter, ++i)
    {
      tree_if_clause *tic = *iter;
      if (tic->is_else_clause ())
        entry_blocks[i] = factory.create<jit_block> ("else");
      else
        entry_blocks[i] = factory.create<jit_block> ("ifelse_cond");
    }

  jit_block *tail = factory.create<jit_block> ("if_tail");
  if (! last_else)
    entry_blocks[entry_blocks.size () - 1] = tail;


  // each branch in the if statement will have different breaks/continues
  block_list current_breaks = breaks;
  block_list current_continues = continues;
  breaks.clear ();
  continues.clear ();

  size_t num_incomming = 0; // number of incomming blocks to our tail
  iter = lst.begin ();
  for (size_t i = 0; iter != lst.end (); ++iter, ++i)
    {
      tree_if_clause *tic = *iter;
      block = entry_blocks[i];
      assert (block);

      if (i) // the first block is prev_block, so it has already been added
        blocks.push_back (entry_blocks[i]);

      if (! tic->is_else_clause ())
        {
          tree_expression *expr = tic->condition ();
          jit_value *cond = visit (expr);
          jit_call *check = create_checked (&jit_typeinfo::logically_true,
                                            cond);
          jit_block *body = factory.create<jit_block> (i == 0 ? "if_body"
                                                       : "ifelse_body");
          blocks.push_back (body);

          jit_instruction *br = factory.create<jit_cond_branch> (check, body,
                                                        entry_blocks[i + 1]);
          block->append (br);
          block = body;
        }

      tree_statement_list *stmt_lst = tic->commands ();
      assert (stmt_lst); // jwe: Can this be null?

      try
        {
          stmt_lst->accept (*this);
          ++num_incomming;
          block->append (factory.create<jit_branch> (tail));
        }
      catch(const jit_break_exception&)
        {}

      current_breaks.splice (current_breaks.end (), breaks);
      current_continues.splice (current_continues.end (), continues);
    }

  breaks.splice (breaks.end (), current_breaks);
  continues.splice (continues.end (), current_continues);

  if (num_incomming || ! last_else)
    {
      blocks.push_back (tail);
      block = tail;
    }
  else
    // every branch broke, so we don't have a tail
    throw jit_break_exception ();
}

void
jit_convert::visit_index_expression (tree_index_expression& exp)
{
  result = resolve (exp);
}

void
jit_convert::visit_matrix (tree_matrix&)
{
  throw jit_fail_exception ();
}

void
jit_convert::visit_cell (tree_cell&)
{
  throw jit_fail_exception ();
}

void
jit_convert::visit_multi_assignment (tree_multi_assignment&)
{
  throw jit_fail_exception ();
}

void
jit_convert::visit_no_op_command (tree_no_op_command&)
{
  throw jit_fail_exception ();
}

void
jit_convert::visit_constant (tree_constant& tc)
{
  octave_value v = tc.rvalue1 ();
  jit_type *ty = jit_typeinfo::type_of (v);

  if (ty == jit_typeinfo::get_scalar ())
    {
      double dv = v.double_value ();
      result = factory.create<jit_const_scalar> (dv);
    }
  else if (ty == jit_typeinfo::get_range ())
    {
      Range rv = v.range_value ();
      result = factory.create<jit_const_range> (rv);
    }
  else if (ty == jit_typeinfo::get_complex ())
    {
      Complex cv = v.complex_value ();
      result = factory.create<jit_const_complex> (cv);
    }
  else
    throw jit_fail_exception ("Unknown constant");
}

void
jit_convert::visit_fcn_handle (tree_fcn_handle&)
{
  throw jit_fail_exception ();
}

void
jit_convert::visit_parameter_list (tree_parameter_list&)
{
  throw jit_fail_exception ();
}

void
jit_convert::visit_postfix_expression (tree_postfix_expression& tpe)
{
  octave_value::unary_op etype = tpe.op_type ();
  tree_expression *operand = tpe.operand ();
  jit_value *operandv = visit (operand);

  const jit_operation& fn = jit_typeinfo::unary_op (etype);
  result = create_checked (fn, operandv);

  if (etype == octave_value::op_incr || etype == octave_value::op_decr)
    {
      jit_value *ret = create_checked (&jit_typeinfo::grab, operandv);
      do_assign (operand, result);
      result = ret;
    }
}

void
jit_convert::visit_prefix_expression (tree_prefix_expression& tpe)
{
  octave_value::unary_op etype = tpe.op_type ();
  tree_expression *operand = tpe.operand ();
  const jit_operation& fn = jit_typeinfo::unary_op (etype);
  result = create_checked (fn, visit (operand));

  if (etype == octave_value::op_incr || etype == octave_value::op_decr)
    do_assign (operand, result);
}

void
jit_convert::visit_return_command (tree_return_command&)
{
  throw jit_fail_exception ();
}

void
jit_convert::visit_return_list (tree_return_list&)
{
  throw jit_fail_exception ();
}

void
jit_convert::visit_simple_assignment (tree_simple_assignment& tsa)
{
  tree_expression *rhs = tsa.right_hand_side ();
  jit_value *rhsv = visit (rhs);
  octave_value::assign_op op = tsa.op_type ();

  if (op != octave_value::op_asn_eq)
    {
      // do the equivlent binary operation, then assign. This is always correct,
      // but isn't always optimal.
      tree_expression *lhs = tsa.left_hand_side ();
      jit_value *lhsv = visit (lhs);
      octave_value::binary_op bop = octave_value::assign_op_to_binary_op (op);
      const jit_operation& fn = jit_typeinfo::binary_op (bop);
      rhsv = create_checked (fn, lhsv, rhsv);
    }

  result = do_assign (tsa.left_hand_side (), rhsv);
}

void
jit_convert::visit_statement (tree_statement& stmt)
{
  tree_command *cmd = stmt.command ();
  tree_expression *expr = stmt.expression ();

  if (cmd)
    visit (cmd);
  else
    {
      // stolen from tree_evaluator::visit_statement
      bool do_bind_ans = false;

      if (expr->is_identifier ())
        {
          tree_identifier *id = dynamic_cast<tree_identifier *> (expr);

          do_bind_ans = (! id->is_variable ());
        }
      else
        do_bind_ans = (! expr->is_assignment_expression ());

      jit_value *expr_result = visit (expr);

      if (do_bind_ans)
        do_assign ("ans", expr_result, expr->print_result ());
      else if (expr->is_identifier () && expr->print_result ())
        {
          // FIXME: ugly hack, we need to come up with a way to pass
          // nargout to visit_identifier
          const jit_operation& fn = jit_typeinfo::print_value ();
          jit_const_string *name = factory.create<jit_const_string> (expr->name ());
          block->append (factory.create<jit_call> (fn, name, expr_result));
        }
    }
}

void
jit_convert::visit_statement_list (tree_statement_list& lst)
{
  for (tree_statement_list::iterator iter = lst.begin (); iter != lst.end();
       ++iter)
    {
      tree_statement *elt = *iter;
      // jwe: Can this ever be null?
      assert (elt);
      elt->accept (*this);
    }
}

void
jit_convert::visit_switch_case (tree_switch_case&)
{
  throw jit_fail_exception ();
}

void
jit_convert::visit_switch_case_list (tree_switch_case_list&)
{
  throw jit_fail_exception ();
}

void
jit_convert::visit_switch_command (tree_switch_command&)
{
  throw jit_fail_exception ();
}

void
jit_convert::visit_try_catch_command (tree_try_catch_command&)
{
  throw jit_fail_exception ();
}

void
jit_convert::visit_unwind_protect_command (tree_unwind_protect_command&)
{
  throw jit_fail_exception ();
}

void
jit_convert::visit_while_command (tree_while_command& wc)
{
  unwind_protect prot;
  prot.protect_var (breaks);
  prot.protect_var (continues);
  breaks.clear ();
  continues.clear ();

  jit_block *cond_check = factory.create<jit_block> ("while_cond_check");
  block->append (factory.create<jit_branch> (cond_check));
  blocks.push_back (cond_check);
  block = cond_check;

  tree_expression *expr = wc.condition ();
  assert (expr && "While expression can not be null");
  jit_value *check = visit (expr);
  check = create_checked (&jit_typeinfo::logically_true, check);

  jit_block *body = factory.create<jit_block> ("while_body");
  blocks.push_back (body);

  jit_block *tail = factory.create<jit_block> ("while_tail");
  block->append (factory.create<jit_cond_branch> (check, body, tail));
  block = body;

  tree_statement_list *loop_body = wc.body ();
  bool all_breaking = false;
  if (loop_body)
    {
      try
        {
          loop_body->accept (*this);
        }
      catch (const jit_break_exception&)
        {
          all_breaking = true;
        }
    }

  finish_breaks (tail, breaks);

  if (! all_breaking || continues.size ())
    {
      jit_block *interrupt_check
        = factory.create<jit_block> ("interrupt_check");
      blocks.push_back (interrupt_check);
      finish_breaks (interrupt_check, continues);
      if (! all_breaking)
        block->append (factory.create<jit_branch> (interrupt_check));

      block = interrupt_check;
      jit_error_check *ec
        = factory.create<jit_error_check> (jit_error_check::var_interrupt,
                                           cond_check, final_block);
      block->append (ec);
    }

  blocks.push_back (tail);
  block = tail;
}

void
jit_convert::visit_do_until_command (tree_do_until_command&)
{
  throw jit_fail_exception ();
}

void
jit_convert::initialize (symbol_table::scope_id s)
{
  scope = s;
  iterator_count = 0;
  for_bounds_count = 0;
  short_count = 0;
  jit_instruction::reset_ids ();

  entry_block = factory.create<jit_block> ("body");
  final_block = factory.create<jit_block> ("final");
  blocks.push_back (entry_block);
  entry_block->mark_alive ();
  block = entry_block;
}

jit_call *
jit_convert::create_checked_impl (jit_call *ret)
{
  block->append (ret);

  jit_block *normal = factory.create<jit_block> (block->name ());
  jit_error_check *check
    = factory.create<jit_error_check> (jit_error_check::var_error_state, ret,
                                       normal, final_block);
  block->append (check);
  blocks.push_back (normal);
  block = normal;

  return ret;
}

jit_variable *
jit_convert::find_variable (const std::string& vname) const
{
  variable_map::const_iterator iter;
  iter = vmap.find (vname);
  return iter != vmap.end () ? iter->second : 0;
}

jit_variable *
jit_convert::get_variable (const std::string& vname)
{
  jit_variable *ret = find_variable (vname);
  if (ret)
    return ret;

  symbol_table::symbol_record record = symbol_table::find_symbol (vname, scope);
  if (record.is_persistent () || record.is_global ())
    throw jit_fail_exception ("Persistent and global not yet supported");

  if (converting_function)
    return create_variable (vname, jit_typeinfo::get_any (), false);
  else
    {
      octave_value val = record.varval ();
      jit_type *type = jit_typeinfo::type_of (val);
      bounds.push_back (type_bound (type, vname));

      return create_variable (vname, type);
    }
}

jit_variable *
jit_convert::create_variable (const std::string& vname, jit_type *type,
                              bool isarg)
{
  jit_variable *var = factory.create<jit_variable> (vname);

  if (isarg)
    {
      jit_extract_argument *extract;
      extract = factory.create<jit_extract_argument> (type, var);
      entry_block->prepend (extract);
    }
  else
    {
      jit_call *init = factory.create<jit_call> (&jit_typeinfo::create_undef);
      jit_assign *assign = factory.create<jit_assign> (var, init);
      entry_block->prepend (assign);
      entry_block->prepend (init);
    }

  return vmap[vname] = var;
}

std::string
jit_convert::next_name (const char *prefix, size_t& count, bool inc)
{
  std::stringstream ss;
  ss << prefix << count;
  if (inc)
    ++count;
  return ss.str ();
}

jit_instruction *
jit_convert::resolve (tree_index_expression& exp, jit_value *extra_arg,
                      bool lhs)
{
  std::string type = exp.type_tags ();
  if (! (type.size () == 1 && type[0] == '('))
    throw jit_fail_exception ("Unsupported index operation");

  std::list<tree_argument_list *> args = exp.arg_lists ();
  if (args.size () != 1)
    throw jit_fail_exception ("Bad number of arguments in "
                              "tree_index_expression");

  tree_argument_list *arg_list = args.front ();
  if (! arg_list)
    throw jit_fail_exception ("null argument list");

  if (arg_list->size () < 1)
    throw jit_fail_exception ("Empty arg_list");

  tree_expression *tree_object = exp.expression ();
  jit_value *object;
  if (lhs)
    {
      tree_identifier *id = dynamic_cast<tree_identifier *> (tree_object);
      if (! id)
        throw jit_fail_exception ("expected identifier");
      object = get_variable (id->name ());
    }
  else
    object = visit (tree_object);

  size_t narg = arg_list->size ();
  tree_argument_list::iterator iter = arg_list->begin ();
  bool have_extra = extra_arg;
  std::vector<jit_value *> call_args (narg + 1 + have_extra);
  call_args[0] = object;

  for (size_t idx = 0; iter != arg_list->end (); ++idx, ++iter)
    {
      unwind_protect prot;
      prot.add_method (&end_context,
                       &std::vector<jit_magic_end::context>::pop_back);

      jit_magic_end::context ctx (factory, object, idx, narg);
      end_context.push_back (ctx);
      call_args[idx + 1] = visit (*iter);
    }

  if (extra_arg)
    call_args[call_args.size () - 1] = extra_arg;

  const jit_operation& fres = lhs ? jit_typeinfo::paren_subsasgn ()
    : jit_typeinfo::paren_subsref ();

  return create_checked (fres, call_args);
}

jit_value *
jit_convert::do_assign (tree_expression *exp, jit_value *rhs, bool artificial)
{
  if (! exp)
    throw jit_fail_exception ("NULL lhs in assign");

  if (isa<tree_identifier> (exp))
    return do_assign (exp->name (), rhs, exp->print_result (), artificial);
  else if (tree_index_expression *idx
           = dynamic_cast<tree_index_expression *> (exp))
    {
      jit_value *new_object = resolve (*idx, rhs, true);
      do_assign (idx->expression (), new_object, true);

      // FIXME: Will not work for values that must be release/grabed
      return rhs;
    }
  else
    throw jit_fail_exception ("Unsupported assignment");
}

jit_value *
jit_convert::do_assign (const std::string& lhs, jit_value *rhs,
                        bool print, bool artificial)
{
  jit_variable *var = get_variable (lhs);
  jit_assign *assign = block->append (factory.create<jit_assign> (var, rhs));

  if (artificial)
    assign->mark_artificial ();

  if (print)
    {
      const jit_operation& print_fn = jit_typeinfo::print_value ();
      jit_const_string *name = factory.create<jit_const_string> (lhs);
      block->append (factory.create<jit_call> (print_fn, name, var));
    }

  return var;
}

jit_value *
jit_convert::visit (tree& tee)
{
  unwind_protect prot;
  prot.protect_var (result);

  tee.accept (*this);
  return result;
}

void
jit_convert::finish_breaks (jit_block *dest, const block_list& lst)
{
  for (block_list::const_iterator iter = lst.begin (); iter != lst.end ();
       ++iter)
    {
      jit_block *b = *iter;
      b->append (factory.create<jit_branch> (dest));
    }
}

// -------------------- jit_convert_llvm --------------------
llvm::Function *
jit_convert_llvm::convert_loop (llvm::Module *module,
                                const jit_block_list& blocks,
                                const std::list<jit_value *>& constants)
{
  converting_function = false;

  // for now just init arguments from entry, later we will have to do something
  // more interesting
  jit_block *entry_block = blocks.front ();
  for (jit_block::iterator iter = entry_block->begin ();
       iter != entry_block->end (); ++iter)
    if (jit_extract_argument *extract
        = dynamic_cast<jit_extract_argument *> (*iter))
      argument_vec.push_back (std::make_pair (extract->name (), true));


  jit_type *any = jit_typeinfo::get_any ();

  // argument is an array of octave_base_value*, or octave_base_value**
  llvm::Type *arg_type = any->to_llvm (); // this is octave_base_value*
  arg_type = arg_type->getPointerTo ();
  llvm::FunctionType *ft = llvm::FunctionType::get (llvm::Type::getVoidTy (context),
                                                    arg_type, false);
  function = llvm::Function::Create (ft, llvm::Function::ExternalLinkage,
                                     "foobar", module);

  try
    {
      prelude = llvm::BasicBlock::Create (context, "prelude", function);
      builder.SetInsertPoint (prelude);

      llvm::Value *arg = function->arg_begin ();
      for (size_t i = 0; i < argument_vec.size (); ++i)
        {
          llvm::Value *loaded_arg = builder.CreateConstInBoundsGEP1_32 (arg, i);
          arguments[argument_vec[i].first] = loaded_arg;
        }

      convert (blocks, constants);
    } catch (const jit_fail_exception& e)
    {
      function->eraseFromParent ();
      throw;
    }

  return function;
}


jit_function
jit_convert_llvm::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)
{
  converting_function = true;

  jit_block *final_block = blocks.back ();
  jit_return *ret = dynamic_cast<jit_return *> (final_block->back ());
  assert (ret);

  creating = jit_function (module, jit_convention::internal,
                           "foobar", ret->result_type (), args);
  function = creating.to_llvm ();

  try
    {
      prelude = creating.new_block ("prelude");
      builder.SetInsertPoint (prelude);

      tree_parameter_list *plist = fcn.parameter_list ();
      if (plist)
        {
          tree_parameter_list::iterator piter = plist->begin ();
          tree_parameter_list::iterator pend = plist->end ();
          for (size_t i = 0; i < args.size () && piter != pend; ++i, ++piter)
            {
              tree_decl_elt *elt = *piter;
              std::string arg_name = elt->name ();
              arguments[arg_name] = creating.argument (builder, i);
            }
        }

      convert (blocks, constants);
    } catch (const jit_fail_exception& e)
    {
      function->eraseFromParent ();
      throw;
    }

  return creating;
}

void
jit_convert_llvm::convert (const jit_block_list& blocks,
                           const std::list<jit_value *>& constants)
{
  std::list<jit_block *>::const_iterator biter;
  for (biter = blocks.begin (); biter != blocks.end (); ++biter)
    {
      jit_block *jblock = *biter;
      llvm::BasicBlock *block = llvm::BasicBlock::Create (context,
                                                          jblock->name (),
                                                          function);
      jblock->stash_llvm (block);
    }

  jit_block *first = *blocks.begin ();
  builder.CreateBr (first->to_llvm ());

  // constants aren't in the IR, we visit those first
  for (std::list<jit_value *>::const_iterator iter = constants.begin ();
       iter != constants.end (); ++iter)
    if (! isa<jit_instruction> (*iter))
      visit (*iter);

  // convert all instructions
  for (biter = blocks.begin (); biter != blocks.end (); ++biter)
    visit (*biter);

  // now finish phi nodes
  for (biter = blocks.begin (); biter != blocks.end (); ++biter)
    {
      jit_block& block = **biter;
      for (jit_block::iterator piter = block.begin ();
           piter != block.end () && isa<jit_phi> (*piter); ++piter)
        {
          jit_instruction *phi = *piter;
          finish_phi (static_cast<jit_phi *> (phi));
        }
    }
}

void
jit_convert_llvm::finish_phi (jit_phi *phi)
{
  llvm::PHINode *llvm_phi = phi->to_llvm ();
  for (size_t i = 0; i < phi->argument_count (); ++i)
    {
      llvm::BasicBlock *pred = phi->incomming_llvm (i);
      llvm_phi->addIncoming (phi->argument_llvm (i), pred);
    }
}

void
jit_convert_llvm::visit (jit_const_string& cs)
{
  cs.stash_llvm (builder.CreateGlobalStringPtr (cs.value ()));
}

void
jit_convert_llvm::visit (jit_const_bool& cb)
{
  cb.stash_llvm (llvm::ConstantInt::get (cb.type_llvm (), cb.value ()));
}

void
jit_convert_llvm::visit (jit_const_scalar& cs)
{
  cs.stash_llvm (llvm::ConstantFP::get (cs.type_llvm (), cs.value ()));
}

void
jit_convert_llvm::visit (jit_const_complex& cc)
{
  llvm::Type *scalar_t = jit_typeinfo::get_scalar_llvm ();
  Complex value = cc.value ();
  llvm::Value *real = llvm::ConstantFP::get (scalar_t, value.real ());
  llvm::Value *imag = llvm::ConstantFP::get (scalar_t, value.imag ());
  cc.stash_llvm (jit_typeinfo::create_complex (real, imag));
}

void jit_convert_llvm::visit (jit_const_index& ci)
{
  ci.stash_llvm (llvm::ConstantInt::get (ci.type_llvm (), ci.value ()));
}

void
jit_convert_llvm::visit (jit_const_range& cr)
{
  llvm::StructType *stype = llvm::cast<llvm::StructType>(cr.type_llvm ());
  llvm::Type *scalar_t = jit_typeinfo::get_scalar_llvm ();
  llvm::Type *idx = jit_typeinfo::get_index_llvm ();
  const jit_range& rng = cr.value ();

  llvm::Constant *constants[4];
  constants[0] = llvm::ConstantFP::get (scalar_t, rng.base);
  constants[1] = llvm::ConstantFP::get (scalar_t, rng.limit);
  constants[2] = llvm::ConstantFP::get (scalar_t, rng.inc);
  constants[3] = llvm::ConstantInt::get (idx, rng.nelem);

  llvm::Value *as_llvm;
  as_llvm = llvm::ConstantStruct::get (stype,
                                       llvm::makeArrayRef (constants, 4));
  cr.stash_llvm (as_llvm);
}

void
jit_convert_llvm::visit (jit_block& b)
{
  llvm::BasicBlock *block = b.to_llvm ();
  builder.SetInsertPoint (block);
  for (jit_block::iterator iter = b.begin (); iter != b.end (); ++iter)
    visit (*iter);
}

void
jit_convert_llvm::visit (jit_branch& b)
{
  b.stash_llvm (builder.CreateBr (b.successor_llvm ()));
}

void
jit_convert_llvm::visit (jit_cond_branch& cb)
{
  llvm::Value *cond = cb.cond_llvm ();
  llvm::Value *br;
  br = builder.CreateCondBr (cond, cb.successor_llvm (0),
                             cb.successor_llvm (1));
  cb.stash_llvm (br);
}

void
jit_convert_llvm::visit (jit_call& call)
{
  const jit_function& ol = call.overload ();

  std::vector<jit_value *> args (call.arguments ().size ());
  for (size_t i = 0; i < args.size (); ++i)
    args[i] = call.argument (i);

  llvm::Value *ret = ol.call (builder, args);
  call.stash_llvm (ret);
}

void
jit_convert_llvm::visit (jit_extract_argument& extract)
{
  llvm::Value *arg = arguments[extract.name ()];
  assert (arg);

  if (converting_function)
    extract.stash_llvm (arg);
  else
    {
      arg = builder.CreateLoad (arg);

      const jit_function& ol = extract.overload ();
      extract.stash_llvm (ol.call (builder, arg));
    }
}

void
jit_convert_llvm::visit (jit_store_argument& store)
{
  const jit_function& ol = store.overload ();
  llvm::Value *arg_value = ol.call (builder, store.result ());
  llvm::Value *arg = arguments[store.name ()];
  store.stash_llvm (builder.CreateStore (arg_value, arg));
}

void
jit_convert_llvm::visit (jit_return& ret)
{
  jit_value *res = ret.result ();

  if (converting_function)
    creating.do_return (builder, res->to_llvm (), false);
  else
    {
      if (res)
        builder.CreateRet (res->to_llvm ());
      else
        builder.CreateRetVoid ();
    }
}

void
jit_convert_llvm::visit (jit_phi& phi)
{
  // we might not have converted all incoming branches, so we don't
  // set incomming branches now
  llvm::PHINode *node = llvm::PHINode::Create (phi.type_llvm (),
                                               phi.argument_count ());
  builder.Insert (node);
  phi.stash_llvm (node);
}

void
jit_convert_llvm::visit (jit_variable&)
{
  throw jit_fail_exception ("ERROR: SSA construction should remove all variables");
}

void
jit_convert_llvm::visit (jit_error_check& check)
{
  llvm::Value *cond;

  switch (check.check_variable ())
    {
    case jit_error_check::var_error_state:
      cond = jit_typeinfo::insert_error_check (builder);
      break;
    case jit_error_check::var_interrupt:
      cond = jit_typeinfo::insert_interrupt_check (builder);
      break;
    default:
      panic_impossible ();
    }

  llvm::Value *br = builder.CreateCondBr (cond, check.successor_llvm (0),
                                          check.successor_llvm (1));
  check.stash_llvm (br);
}

void
jit_convert_llvm::visit (jit_assign& assign)
{
  jit_value *new_value = assign.src ();
  assign.stash_llvm (new_value->to_llvm ());

  if (assign.artificial ())
    return;

  jit_value *overwrite = assign.overwrite ();
  if (isa<jit_assign_base> (overwrite))
    {
      const jit_function& ol = jit_typeinfo::get_release (overwrite->type ());
      if (ol.valid ())
        ol.call (builder, overwrite);
    }
}

void
jit_convert_llvm::visit (jit_argument&)
{}

void
jit_convert_llvm::visit (jit_magic_end& me)
{
  const jit_function& ol = me.overload ();

  jit_magic_end::context ctx = me.resolve_context ();
  llvm::Value *ret = ol.call (builder, ctx.value, ctx.index, ctx.count);
  me.stash_llvm (ret);
}

// -------------------- jit_infer --------------------
jit_infer::jit_infer (jit_factory& afactory, jit_block_list& ablocks,
                      const variable_map& avmap)
  : blocks (ablocks), factory (afactory), vmap (avmap) {}

void
jit_infer::infer (void)
{
  construct_ssa ();

  // initialize the worklist to instructions derived from constants
  const std::list<jit_value *>& constants = factory.constants ();
  for (std::list<jit_value *>::const_iterator iter = constants.begin ();
       iter != constants.end (); ++iter)
    append_users (*iter);

  // the entry block terminator may be a regular branch statement
  if (entry_block ().terminator ())
    push_worklist (entry_block ().terminator ());

  // FIXME: Describe algorithm here
  while (worklist.size ())
    {
      jit_instruction *next = worklist.front ();
      worklist.pop_front ();
      next->stash_in_worklist (false);

      if (next->infer ())
        {
          // terminators need to be handles specially
          if (jit_terminator *term = dynamic_cast<jit_terminator *> (next))
            append_users_term (term);
          else
            append_users (next);
        }
    }

  remove_dead ();
  blocks.label ();
  place_releases ();
  simplify_phi ();
}

void
jit_infer::append_users (jit_value *v)
{
  for (jit_use *use = v->first_use (); use; use = use->next ())
    push_worklist (use->user ());
}

void
jit_infer::append_users_term (jit_terminator *term)
{
  for (size_t i = 0; i < term->successor_count (); ++i)
    {
      if (term->alive (i))
        {
          jit_block *succ = term->successor (i);
          for (jit_block::iterator iter = succ->begin (); iter != succ->end ()
                 && isa<jit_phi> (*iter); ++iter)
            push_worklist (*iter);

          jit_terminator *sterm = succ->terminator ();
          if (sterm)
            push_worklist (sterm);
        }
    }
}

void
jit_infer::construct_ssa (void)
{
  blocks.label ();
  final_block ().compute_idom (entry_block ());
  entry_block ().compute_df ();
  entry_block ().create_dom_tree ();

  // insert phi nodes where needed, this is done on a per variable basis
  for (variable_map::const_iterator iter = vmap.begin (); iter != vmap.end ();
       ++iter)
    {
      jit_block::df_set visited, added_phi;
      std::list<jit_block *> ssa_worklist;
      iter->second->use_blocks (visited);
      ssa_worklist.insert (ssa_worklist.begin (), visited.begin (),
                           visited.end ());

      while (ssa_worklist.size ())
        {
          jit_block *b = ssa_worklist.front ();
          ssa_worklist.pop_front ();

          for (jit_block::df_iterator diter = b->df_begin ();
               diter != b->df_end (); ++diter)
            {
              jit_block *dblock = *diter;
              if (! added_phi.count (dblock))
                {
                  jit_phi *phi = factory.create<jit_phi> (iter->second,
                                                  dblock->use_count ());
                  dblock->prepend (phi);
                  added_phi.insert (dblock);
                }

              if (! visited.count (dblock))
                {
                  ssa_worklist.push_back (dblock);
                  visited.insert (dblock);
                }
            }
        }
    }

  do_construct_ssa (entry_block (), entry_block ().visit_count ());
}

void
jit_infer::do_construct_ssa (jit_block& ablock, size_t avisit_count)
{
  if (ablock.visited (avisit_count))
    return;

  // replace variables with their current SSA value
  for (jit_block::iterator iter = ablock.begin (); iter != ablock.end ();
       ++iter)
    {
      jit_instruction *instr = *iter;
      instr->construct_ssa ();
      instr->push_variable ();
    }

  // finish phi nodes of successors
  for (size_t i = 0; i < ablock.successor_count (); ++i)
    {
      jit_block *finish = ablock.successor (i);

      for (jit_block::iterator iter = finish->begin (); iter != finish->end ()
             && isa<jit_phi> (*iter);)
        {
          jit_phi *phi = static_cast<jit_phi *> (*iter);
          jit_variable *var = phi->dest ();
          ++iter;

          if (var->has_top ())
            phi->add_incomming (&ablock, var->top ());
          else
            {
              // temporaries may have extranious phi nodes which can be removed
              assert (! phi->use_count ());
              assert (var->name ().size () && var->name ()[0] == '#');
              phi->remove ();
            }
        }
    }

  for (size_t i = 0; i < ablock.dom_successor_count (); ++i)
    do_construct_ssa (*ablock.dom_successor (i), avisit_count);

  ablock.pop_all ();
}

void
jit_infer::place_releases (void)
{
  std::set<jit_value *> temporaries;
  for (jit_block_list::iterator iter = blocks.begin (); iter != blocks.end ();
       ++iter)
    {
      jit_block& ablock = **iter;
      if (ablock.id () != jit_block::NO_ID)
        {
          release_temp (ablock, temporaries);
          release_dead_phi (ablock);
        }
    }
}

void
jit_infer::push_worklist (jit_instruction *instr)
{
  if (! instr->in_worklist ())
    {
      instr->stash_in_worklist (true);
      worklist.push_back (instr);
    }
}

void
jit_infer::remove_dead ()
{
  jit_block_list::iterator biter;
  for (biter = blocks.begin (); biter != blocks.end (); ++biter)
    {
      jit_block *b = *biter;
      if (b->alive ())
        {
          for (jit_block::iterator iter = b->begin (); iter != b->end ()
                 && isa<jit_phi> (*iter);)
            {
              jit_phi *phi = static_cast<jit_phi *> (*iter);
              if (phi->prune ())
                iter = b->remove (iter);
              else
                ++iter;
            }
        }
    }

  for (biter = blocks.begin (); biter != blocks.end ();)
    {
      jit_block *b = *biter;
      if (b->alive ())
        {
          // FIXME: A special case for jit_error_check, if we generalize to
          // we will need to change!
          jit_terminator *term = b->terminator ();
          if (term && term->successor_count () == 2 && ! term->alive (0))
            {
              jit_block *succ = term->successor (1);
              term->remove ();
              jit_branch *abreak = factory.create<jit_branch> (succ);
              b->append (abreak);
              abreak->infer ();
            }

          ++biter;
        }
      else
        {
          jit_terminator *term = b->terminator ();
          if (term)
            term->remove ();
          biter = blocks.erase (biter);
        }
    }
}

void
jit_infer::release_dead_phi (jit_block& ablock)
{
  jit_block::iterator iter = ablock.begin ();
  while (iter != ablock.end () && isa<jit_phi> (*iter))
    {
      jit_phi *phi = static_cast<jit_phi *> (*iter);
      ++iter;

      jit_use *use = phi->first_use ();
      if (phi->use_count () == 1 && isa<jit_assign> (use->user ()))
        {
          // instead of releasing on assign, release on all incomming branches,
          // this can get rid of casts inside loops
          for (size_t i = 0; i < phi->argument_count (); ++i)
            {
              jit_value *arg = phi->argument (i);
              if (! arg->needs_release ())
                continue;

              jit_block *inc = phi->incomming (i);
              jit_block *split = inc->maybe_split (factory, blocks, ablock);
              jit_terminator *term = split->terminator ();
              jit_call *release
                = factory.create<jit_call> (jit_typeinfo::release, arg);
              release->infer ();
              split->insert_before (term, release);
            }

          phi->replace_with (0);
          phi->remove ();
        }
    }
}

void
jit_infer::release_temp (jit_block& ablock, std::set<jit_value *>& temp)
{
  for (jit_block::iterator iter = ablock.begin (); iter != ablock.end ();
       ++iter)
    {
      jit_instruction *instr = *iter;

      // check for temporaries that require release and live across
      // multiple blocks
      if (instr->needs_release ())
        {
          jit_block *fu_block = instr->first_use_block ();
          if (fu_block && fu_block != &ablock && instr->needs_release ())
            temp.insert (instr);
        }

      if (isa<jit_call> (instr))
        {
          // place releases for temporary arguments
          for (size_t i = 0; i < instr->argument_count (); ++i)
            {
              jit_value *arg = instr->argument (i);
              if (! arg->needs_release ())
                continue;

              jit_call *release
                = factory.create<jit_call> (&jit_typeinfo::release, arg);
              release->infer ();
              ablock.insert_after (iter, release);
              ++iter;
              temp.erase (arg);
            }
        }
    }

  if (! temp.size () || ! isa<jit_error_check> (ablock.terminator ()))
    return;

  // FIXME: If we support try/catch or unwind_protect final_block may not be the
  // destination
  jit_block *split = ablock.maybe_split (factory, blocks, final_block ());
  jit_terminator *term = split->terminator ();
  for (std::set<jit_value *>::const_iterator iter = temp.begin ();
       iter != temp.end (); ++iter)
    {
      jit_value *value = *iter;
      jit_call *release
        = factory.create<jit_call> (&jit_typeinfo::release, value);
      split->insert_before (term, release);
      release->infer ();
    }
}

void
jit_infer::simplify_phi (void)
{
  for (jit_block_list::iterator biter = blocks.begin (); biter != blocks.end ();
       ++biter)
    {
      jit_block &ablock = **biter;
      for (jit_block::iterator iter = ablock.begin (); iter != ablock.end ()
             && isa<jit_phi> (*iter); ++iter)
        simplify_phi (*static_cast<jit_phi *> (*iter));
    }
}

void
jit_infer::simplify_phi (jit_phi& phi)
{
  jit_block& pblock = *phi.parent ();
  const jit_operation& cast_fn = jit_typeinfo::cast (phi.type ());
  jit_variable *dest = phi.dest ();
  for (size_t i = 0; i < phi.argument_count (); ++i)
    {
      jit_value *arg = phi.argument (i);
      if (arg->type () != phi.type ())
        {
          jit_block *pred = phi.incomming (i);
          jit_block *split = pred->maybe_split (factory, blocks, pblock);
          jit_terminator *term = split->terminator ();
          jit_instruction *cast = factory.create<jit_call> (cast_fn, arg);
          jit_assign *assign = factory.create<jit_assign> (dest, cast);

          split->insert_before (term, cast);
          split->insert_before (term, assign);
          cast->infer ();
          assign->infer ();
          phi.stash_argument (i, assign);
        }
    }
}

// -------------------- tree_jit --------------------

tree_jit::tree_jit (void) : module (0), engine (0)
{
}

tree_jit::~tree_jit (void)
{}

bool
tree_jit::execute (tree_simple_for_command& cmd, const octave_value& bounds)
{
  return instance ().do_execute (cmd, bounds);
}

bool
tree_jit::execute (tree_while_command& cmd)
{
  return instance ().do_execute (cmd);
}

bool
tree_jit::execute (octave_user_function& fcn, const octave_value_list& args,
                   octave_value_list& retval)
{
  return instance ().do_execute (fcn, args, retval);
}

tree_jit&
tree_jit::instance (void)
{
  static tree_jit ret;
  return ret;
}

bool
tree_jit::initialize (void)
{
  if (engine)
    return true;

  if (! module)
    {
      llvm::InitializeNativeTarget ();
      module = new llvm::Module ("octave", context);
    }

  // sometimes this fails pre main
  engine = llvm::ExecutionEngine::createJIT (module);

  if (! engine)
    return false;

  module_pass_manager = new llvm::PassManager ();
  module_pass_manager->add (llvm::createAlwaysInlinerPass ());

  pass_manager = new llvm::FunctionPassManager (module);
  pass_manager->add (new llvm::TargetData(*engine->getTargetData ()));
  pass_manager->add (llvm::createCFGSimplificationPass ());
  pass_manager->add (llvm::createBasicAliasAnalysisPass ());
  pass_manager->add (llvm::createPromoteMemoryToRegisterPass ());
  pass_manager->add (llvm::createInstructionCombiningPass ());
  pass_manager->add (llvm::createReassociatePass ());
  pass_manager->add (llvm::createGVNPass ());
  pass_manager->add (llvm::createCFGSimplificationPass ());
  pass_manager->doInitialization ();

  jit_typeinfo::initialize (module, engine);

  return true;
}

bool
tree_jit::do_execute (tree_simple_for_command& cmd, const octave_value& bounds)
{
  const size_t MIN_TRIP_COUNT = 1000;

  size_t tc = trip_count (bounds);
  if (! tc || ! initialize () || ! enabled ())
    return false;

  jit_info::vmap extra_vars;
  extra_vars["#for_bounds0"] = &bounds;

  jit_info *info = cmd.get_info ();
  if (! info || ! info->match (extra_vars))
    {
      if (tc < MIN_TRIP_COUNT)
        return false;

      delete info;
      info = new jit_info (*this, cmd, bounds);
      cmd.stash_info (info);
    }

  return info->execute (extra_vars);
}

bool
tree_jit::do_execute (tree_while_command& cmd)
{
  if (! initialize () || ! enabled ())
    return false;

  jit_info *info = cmd.get_info ();
  if (! info || ! info->match ())
    {
      delete info;
      info = new jit_info (*this, cmd);
      cmd.stash_info (info);
    }

  return info->execute ();
}

bool
tree_jit::do_execute (octave_user_function& fcn, const octave_value_list& args,
                      octave_value_list& retval)
{
  if (! initialize () || ! enabled ())
    return false;

  jit_function_info *info = fcn.get_info ();
    if (! info || ! info->match (args))
      {
        delete info;
        info = new jit_function_info (*this, fcn, args);
        fcn.stash_info (info);
      }

    return info->execute (args, retval);
}

bool
tree_jit::enabled (void)
{
  // Ideally, we should only disable JIT if there is a breakpoint in the code we
  // are about to run. However, we can't figure this out in O(1) time, so we
  // conservatively check for the existence of any breakpoints.
  return Venable_jit_compiler && ! bp_table::have_breakpoints ()
    && ! Vdebug_on_interrupt && ! Vdebug_on_error;
}

size_t
tree_jit::trip_count (const octave_value& bounds) const
{
  if (bounds.is_range ())
    {
      Range rng = bounds.range_value ();
      return rng.nelem ();
    }

  // unsupported type
  return 0;
}


void
tree_jit::optimize (llvm::Function *fn)
{
  if (Venable_jit_debugging)
    llvm::verifyModule (*module);

  module_pass_manager->run (*module);
  pass_manager->run (*fn);

  if (Venable_jit_debugging)
    {
      std::string error;
      llvm::raw_fd_ostream fout ("test.bc", error,
                                 llvm::raw_fd_ostream::F_Binary);
      llvm::WriteBitcodeToFile (module, fout);
    }
}

// -------------------- jit_function_info --------------------
jit_function_info::jit_function_info (tree_jit& tjit,
                                      octave_user_function& fcn,
                                      const octave_value_list& ov_args)
  : argument_types (ov_args.length ()), function (0)
{
  size_t nargs = ov_args.length ();
  for (size_t i = 0; i < nargs; ++i)
    argument_types[i] = jit_typeinfo::type_of (ov_args(i));

  jit_function raw_fn;
  jit_function wrapper;

  try
    {
      jit_convert conv (fcn, argument_types);
      jit_infer infer (conv.get_factory (), conv.get_blocks (),
                       conv.get_variable_map ());
      infer.infer ();

      if (Venable_jit_debugging)
        {
          jit_block_list& blocks = infer.get_blocks ();
          blocks.label ();
          std::cout << "-------------------- Compiling function ";
          std::cout << "--------------------\n";

          tree_print_code tpc (std::cout);
          tpc.visit_octave_user_function_header (fcn);
          tpc.visit_statement_list (*fcn.body ());
          tpc.visit_octave_user_function_trailer (fcn);
          blocks.print (std::cout, "octave jit ir");
        }

      jit_factory& factory = conv.get_factory ();
      llvm::Module *module = tjit.get_module ();
      jit_convert_llvm to_llvm;
      raw_fn = to_llvm.convert_function (module, infer.get_blocks (),
                                         factory.constants (), fcn,
                                         argument_types);

      if (Venable_jit_debugging)
        {
          std::cout << "-------------------- raw function ";
          std::cout << "--------------------\n";
          std::cout << *raw_fn.to_llvm () << std::endl;
          llvm::verifyFunction (*raw_fn.to_llvm ());
        }

      std::string wrapper_name = fcn.name () + "_wrapper";
      jit_type *any_t = jit_typeinfo::get_any ();
      std::vector<jit_type *> wrapper_args (1, jit_typeinfo::get_any_ptr ());
      wrapper = jit_function (module, jit_convention::internal, wrapper_name,
                              any_t, wrapper_args);

      llvm::BasicBlock *wrapper_body = wrapper.new_block ();
      builder.SetInsertPoint (wrapper_body);

      llvm::Value *wrapper_arg = wrapper.argument (builder, 0);
      std::vector<llvm::Value *> raw_args (nargs);
      for (size_t i = 0; i < nargs; ++i)
        {
          llvm::Value *arg;
          arg = builder.CreateConstInBoundsGEP1_32 (wrapper_arg, i);
          arg = builder.CreateLoad (arg);

          jit_type *arg_type = argument_types[i];
          const jit_function& cast = jit_typeinfo::cast (arg_type, any_t);
          raw_args[i] = cast.call (builder, arg);
        }

      llvm::Value *result = raw_fn.call (builder, raw_args);
      if (raw_fn.result ())
        {
          jit_type *raw_result_t = raw_fn.result ();
          const jit_function& cast = jit_typeinfo::cast (any_t, raw_result_t);
          result = cast.call (builder, result);
        }
      else
        {
          llvm::Value *zero = builder.getInt32 (0);
          result = builder.CreateBitCast (zero, any_t->to_llvm ());
        }

      wrapper.do_return (builder, result);

      llvm::Function *llvm_function = wrapper.to_llvm ();
      tjit.optimize (llvm_function);

      if (Venable_jit_debugging)
        {
          std::cout << "-------------------- optimized and wrapped ";
          std::cout << "--------------------\n";
          std::cout << *llvm_function << std::endl;
          llvm::verifyFunction (*llvm_function);
        }

      llvm::ExecutionEngine* engine = tjit.get_engine ();
      void *void_fn = engine->getPointerToFunction (llvm_function);
      function = reinterpret_cast<jited_function> (void_fn);
    }
  catch (const jit_fail_exception& e)
    {
      argument_types.clear ();

      if (Venable_jit_debugging)
        {
          if (e.known ())
            std::cout << "jit fail: " << e.what () << std::endl;
        }

      wrapper.erase ();
      raw_fn.erase ();
    }
}

bool
jit_function_info::execute (const octave_value_list& ov_args,
                            octave_value_list& retval) const
{
  if (! function)
    return false;

  // TODO figure out a way to delete ov_args so we avoid duplicating refcount
  size_t nargs = ov_args.length ();
  std::vector<octave_base_value *> args (nargs);
  for (size_t i = 0; i < nargs; ++i)
    {
      octave_base_value *obv = ov_args(i).internal_rep ();
      obv->grab ();
      args[i] = obv;
    }

  octave_base_value *ret = function (&args[0]);
  if (ret)
    retval(0) = octave_value (ret);

  octave_quit ();

  return true;
}

bool
jit_function_info::match (const octave_value_list& ov_args) const
{
  if (! function)
    return true;

  size_t nargs = ov_args.length ();
  if (nargs != argument_types.size ())
    return false;

  for (size_t i = 0; i < nargs; ++i)
    if (jit_typeinfo::type_of (ov_args(i)) != argument_types[i])
      return false;

  return true;
}

// -------------------- jit_info --------------------
jit_info::jit_info (tree_jit& tjit, tree& tee)
  : engine (tjit.get_engine ()), function (0), llvm_function (0)
{
  compile (tjit, tee);
}

jit_info::jit_info (tree_jit& tjit, tree& tee, const octave_value& for_bounds)
  : engine (tjit.get_engine ()), function (0), llvm_function (0)
{
  compile (tjit, tee, jit_typeinfo::type_of (for_bounds));
}

jit_info::~jit_info (void)
{
  if (llvm_function)
    llvm_function->eraseFromParent ();
}

bool
jit_info::execute (const vmap& extra_vars) const
{
  if (! function)
    return false;

  std::vector<octave_base_value *> real_arguments (arguments.size ());
  for (size_t i = 0; i < arguments.size (); ++i)
    {
      if (arguments[i].second)
        {
          octave_value current = find (extra_vars, arguments[i].first);
          octave_base_value *obv = current.internal_rep ();
          obv->grab ();
          real_arguments[i] = obv;
        }
    }

  function (&real_arguments[0]);

  for (size_t i = 0; i < arguments.size (); ++i)
    {
      const std::string& name = arguments[i].first;

      // do not store for loop bounds temporary
      if (name.size () && name[0] != '#')
        symbol_table::varref (arguments[i].first) = real_arguments[i];
    }

  octave_quit ();

  return true;
}

bool
jit_info::match (const vmap& extra_vars) const
{
  if (! function)
    return true;

  for (size_t i = 0; i < bounds.size (); ++i)
    {
      const std::string& arg_name = bounds[i].second;
      octave_value value = find (extra_vars, arg_name);
      jit_type *type = jit_typeinfo::type_of (value);

      // FIXME: Check for a parent relationship
      if (type != bounds[i].first)
        return false;
    }

  return true;
}

void
jit_info::compile (tree_jit& tjit, tree& tee, jit_type *for_bounds)
{
  try
    {
      jit_convert conv (tee, for_bounds);
      jit_infer infer (conv.get_factory (), conv.get_blocks (),
                       conv.get_variable_map ());

      infer.infer ();

      if (Venable_jit_debugging)
        {
          jit_block_list& blocks = infer.get_blocks ();
          blocks.label ();
          std::cout << "-------------------- Compiling tree --------------------\n";
          std::cout << tee.str_print_code () << std::endl;
          blocks.print (std::cout, "octave jit ir");
        }

      jit_factory& factory = conv.get_factory ();
      jit_convert_llvm to_llvm;
      llvm_function = to_llvm.convert_loop (tjit.get_module (),
                                            infer.get_blocks (),
                                            factory.constants ());
      arguments = to_llvm.get_arguments ();
      bounds = conv.get_bounds ();
    }
  catch (const jit_fail_exception& e)
    {
      if (Venable_jit_debugging)
        {
          if (e.known ())
            std::cout << "jit fail: " << e.what () << std::endl;
        }
    }

  if (llvm_function)
    {
      if (Venable_jit_debugging)
        {
          std::cout << "-------------------- llvm ir --------------------";
          std::cout << *llvm_function << std::endl;
          llvm::verifyFunction (*llvm_function);
        }

      tjit.optimize (llvm_function);

      if (Venable_jit_debugging)
        {
          std::cout << "-------------------- optimized llvm ir "
                    << "--------------------\n";
          std::cout << *llvm_function << std::endl;
        }

      void *void_fn = engine->getPointerToFunction (llvm_function);
      function = reinterpret_cast<jited_function> (void_fn);
    }
}

octave_value
jit_info::find (const vmap& extra_vars, const std::string& vname) const
{
  vmap::const_iterator iter = extra_vars.find (vname);
  return iter == extra_vars.end () ? symbol_table::varval (vname)
    : *iter->second;
}

#endif

DEFUN (enable_jit_debugging, args, nargout,
  "-*- texinfo -*-\n\
@deftypefn  {Built-in Function} {@var{val} =} enable_jit_debugging ()\n\
@deftypefnx {Built-in Function} {@var{old_val} =} enable_jit_debugging (@var{new_val})\n\
@deftypefnx {Built-in Function} {} enable_jit_debugging (@var{new_val}, \"local\")\n\
Query or set the internal variable that determines whether\n\
debugging/tracing is enabled for Octave's JIT compiler.\n\
\n\
When called from inside a function with the \"local\" option, the variable is\n\
changed locally for the function and any subroutines it calls.  The original\n\
variable value is restored when exiting the function.\n\
@seealso{enable_jit_compiler}\n\
@end deftypefn")
{
#if defined (HAVE_LLVM)
  return SET_INTERNAL_VARIABLE (enable_jit_debugging);
#else
  warning ("enable_jit_debugging: JIT compiling not available in this version of Octave");
  return octave_value ();
#endif
}

DEFUN (enable_jit_compiler, args, nargout,
  "-*- texinfo -*-\n\
@deftypefn  {Built-in Function} {@var{val} =} enable_jit_compiler ()\n\
@deftypefnx {Built-in Function} {@var{old_val} =} enable_jit_compiler (@var{new_val})\n\
@deftypefnx {Built-in Function} {} enable_jit_compiler (@var{new_val}, \"local\")\n\
Query or set the internal variable that enables Octave's JIT compiler.\n\
\n\
When called from inside a function with the \"local\" option, the variable is\n\
changed locally for the function and any subroutines it calls.  The original\n\
variable value is restored when exiting the function.\n\
@seealso{enable_jit_debugging}\n\
@end deftypefn")
{
#if defined (HAVE_LLVM)
  return SET_INTERNAL_VARIABLE (enable_jit_compiler);
#else
  warning ("enable_jit_compiler: JIT compiling not available in this version of Octave");
  return octave_value ();
#endif
}

/*
Test some simple cases that compile.

%!test
%! for i=1:1e6
%!   if i < 5
%!     break
%!   else
%!     break
%!   endif
%! endfor
%! assert (i, 1);

%!test
%! while 1
%!   if 1
%!     break
%!  else
%!    break
%!  endif
%! endwhile

%!test
%! for i=1:1e6
%!   if i == 100
%!     break
%!   endif
%! endfor
%! assert (i, 100);

%!test
%! inc = 1e-5;
%! result = 0;
%! for ii = 0:inc:1
%!   result = result + inc * (1/3 * ii * ii);
%! endfor
%! assert (abs (result - 1/9) < 1e-5);

%!test
%! inc = 1e-5;
%! result = 0;
%! for ii = 0:inc:1
%!   # the ^ operator's result is complex
%!   result = result + inc * (1/3 * ii ^ 2);
%! endfor
%! assert (abs (result - 1/9) < 1e-5);

%!test
%! temp = 1+1i;
%! nan = NaN;
%! while 1
%!   temp = temp - 1i;
%!   temp = temp * nan;
%!   break;
%! endwhile
%! assert (imag (temp), 0);

%!test
%! temp = 1+1i;
%! nan = NaN+1i;
%! while 1
%!   nan = nan - 1i;
%!   temp = temp - 1i;
%!   temp = temp * nan;
%!   break;
%! endwhile
%! assert (imag (temp), 0);

%!test
%! temp = 1+1i;
%! while 1
%!   temp = temp * 5;
%!   break;
%! endwhile
%! assert (temp, 5+5i);

%!test
%! nr = 1001;
%! mat = zeros (1, nr);
%! for i = 1:nr
%!   mat(i) = i;
%! endfor
%! assert (mat == 1:nr);

%!test
%! nr = 1001;
%! mat = 1:nr;
%! mat(end) = 0; # force mat to a matrix
%! total = 0;
%! for i = 1:nr
%!   total = mat(i) + total;
%! endfor
%! assert (sum (mat) == total);

%!test
%! nr = 1001;
%! mat = [3 1 5];
%! try
%!   for i = 1:nr
%!     if i > 500
%!       result = mat(100);
%!     else
%!       result = i;
%!     endif
%!   endfor
%! catch
%! end
%! assert (result == 500);

%!function result = gen_test (n)
%!  result = double (rand (1, n) > .01);
%!endfunction

%!function z = vectorized (A, K)
%!  temp = ones (1, K);
%!  z = conv (A, temp);
%!  z = z > K-1;
%!  z = conv (z, temp);
%!  z = z(K:end-K+1);
%!  z = z >= 1;
%!endfunction

%!function z = loopy (A, K)
%!  z = A;
%!  n = numel (A);
%!  counter = 0;
%!  for ii=1:n
%!    if z(ii)
%!      counter = counter + 1;
%!    else
%!      if counter > 0 && counter < K
%!        z(ii-counter:ii-1) = 0;
%!      endif
%!      counter = 0;
%!    endif
%!  endfor
%!
%!  if counter > 0 && counter < K
%!    z(end-counter+1:end) = 0;
%!  endif
%!endfunction

%!test
%! test_set = gen_test (10000);
%! assert (all (vectorized (test_set, 3) == loopy (test_set, 3)));

%!test
%! niter = 1001;
%! i = 0;
%! while (i < niter)
%!   i = i + 1;
%! endwhile
%! assert (i == niter);

%!test
%! niter = 1001;
%! result = 0;
%! m = [5 10];
%! for i=1:niter
%!   result = result + m(end);
%! endfor
%! assert (result == m(end) * niter);

%!test
%! ndim = 100;
%! result = 0;
%! m = zeros (ndim);
%! m(:) = 1:ndim^2;
%! i = 1;
%! while (i <= ndim)
%!   for j = 1:ndim
%!     result = result + m(i, j);
%!    endfor
%!   i = i + 1;
%! endwhile
%! assert (result == sum (sum (m)));

%!test
%! ndim = 100;
%! m = zeros (ndim);
%! i = 1;
%! while (i <= ndim)
%!   for j = 1:ndim
%!     m(i, j) = (j - 1) * ndim + i;
%!   endfor
%!   i = i + 1;
%! endwhile
%! m2 = zeros (ndim);
%! m2(:) = 1:(ndim^2);
%! assert (all (m == m2));

%!test
%! ndim = 2;
%! m = zeros (ndim, ndim, ndim, ndim);
%! result = 0;
%! i0 = 1;
%! while (i0 <= ndim)
%!   for i1 = 1:ndim
%!     for i2 = 1:ndim
%!       for i3 = 1:ndim
%!         m(i0, i1, i2, i3) = 1;
%!         m(i0, i1, i2, i3, 1, 1, 1, 1, 1, 1) = 1;
%!         result = result + m(i0, i1, i2, i3);
%!       endfor
%!     endfor
%!   endfor
%!   i0 = i0 + 1;
%! endwhile
%! expected = ones (ndim, ndim, ndim, ndim);
%! assert (all (m == expected));
%! assert (result == sum (expected (:)));

%!function test_divide ()
%! state = warning ("query", "Octave:divide-by-zero").state;
%! unwind_protect
%!   warning ("error", "Octave:divide-by-zero");
%!   for i=1:1e5
%!     a = 1;
%!     a / 0;
%!   endfor
%! unwind_protect_cleanup
%!   warning (state, "Octave:divide-by-zero");
%! end_unwind_protect
%!endfunction

%!error <division by zero> test_divide ()

%!test
%! while 1
%!   a = 0;
%!   result = a / 1;
%!   break;
%! endwhile
%! assert (result, 0);

%!test
%! m = zeros (2, 1001);
%! for i=1:1001
%!   m(end, i) = i;
%!   m(end - 1, end - i + 1) = i;
%! endfor
%! m2 = zeros (2, 1001);
%! m2(1, :) = fliplr (1:1001);
%! m2(2, :) = 1:1001;
%! assert (m, m2);

%!test
%! m = [1 2 3];
%! for i=1:1001
%!   m = sin (m);
%!   break;
%! endfor
%! assert (m == sin ([1  2 3]));

%!test
%! i = 0;
%! while i < 10
%!   i += 1;
%! endwhile
%! assert (i == 10);

%!test
%! i = 0;
%! while i < 10
%!   a = ++i;
%! endwhile
%! assert (i == 10);
%! assert (a == 10);
%!test
%! i = 0;
%! while i < 10
%!   a = i++;
%! endwhile
%! assert (i == 10);
%! assert (a == 9);

%!test
%! num = 2;
%! a = zeros (1, num);
%! i = 1;
%! while i <= num
%!   a(i) = norm (eye (i));
%!   ++i;
%! endwhile
%! assert (a, ones (1, num));

%!function test_compute_idom ()
%! while (li <= length (l1) && si <= length (s1))
%!   if (l1 (li) < s1 (si))
%!     if (li == si)
%!       break;
%!     endif;
%!     li++;
%!   else
%!     si++;
%!   endif;
%! endwhile

%!error test_compute_idom ()

%!function x = test_overload (a)
%!  while 1
%!    x = a;
%!    break;
%!  endwhile
%!endfunction

%!assert (test_overload (1), 1);
%!assert (test_overload ([1 2]), [1 2]);

%!function a = bubble (a = [3 2 1])
%!  swapped = 1;
%!  n = length (a);
%!  while (swapped)
%!    swapped = 0;
%!    for i = 1:n-1
%!      if a(i) > a(i + 1)
%!        swapped = 1;
%!        temp = a(i);
%!        a(i) = a(i + 1);
%!        a(i + 1) = temp;
%!      endif
%!    endfor
%!  endwhile
%!endfunction

%!assert (bubble (), [1 2 3]);

%!test
%! a = 0;
%! b = 1;
%! for i=1:1e3
%!   for j=1:2
%!     a = a + b;
%!   endfor
%! endfor
%! assert (a, 2000);
%! assert (b, 1);

%!test
%! a = [1+1i 1+2i];
%! b = 0;
%! while 1
%!   b = a(1);
%!   break;
%! endwhile
%! assert (b, a(1));

%!function test_undef ()
%!  for i=1:1e7
%!    XXX;
%!  endfor
%!endfunction

%!error <undefined near> (test_undef);

%!shared id
%! id = @(x) x;

%!assert (id (1), 1);
%!assert (id (1+1i), 1+1i)
%!assert (id (1, 2), 1)
%!error <undefined> (id ())


*/