/* Copyright 2014-2015 Samsung Electronics Co., Ltd.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "ecma-alloc.h"
#include "ecma-builtins.h"
#include "ecma-gc.h"
#include "ecma-globals.h"
#include "ecma-helpers.h"
#include "ecma-lex-env.h"
#include "ecma-stack.h"
#include "jrt.h"
#include "vm.h"
#include "jrt-libc-includes.h"
#include "mem-allocator.h"

/**
 * Top (current) interpreter context
 */
int_data_t *vm_top_context_p = NULL;

#define __INIT_OP_FUNC(name, arg1, arg2, arg3) [ __op__idx_##name ] = opfunc_##name,
static const opfunc __opfuncs[LAST_OP] =
{
  OP_LIST (INIT_OP_FUNC)
};
#undef __INIT_OP_FUNC

JERRY_STATIC_ASSERT (sizeof (opcode_t) <= 4);

const opcode_t *__program = NULL;

#ifdef MEM_STATS
#define __OP_FUNC_NAME(name, arg1, arg2, arg3) #name,
static const char *__op_names[LAST_OP] =
{
  OP_LIST (OP_FUNC_NAME)
};
#undef __OP_FUNC_NAME

#define INTERP_MEM_PRINT_INDENTATION_STEP (5)
#define INTERP_MEM_PRINT_INDENTATION_MAX  (125)
static uint32_t interp_mem_stats_print_indentation = 0;
static bool interp_mem_stats_enabled = false;

static void
interp_mem_stats_print_legend (void)
{
  if (likely (!interp_mem_stats_enabled))
  {
    return;
  }

  printf ("----- Legend of memory usage trace during interpretation -----\n\n"
          "\tEntering block = beginning execution of initial (global) scope or function.\n\n"
          "\tInformation on each value is formatted as following: (p -> n ( [+-]c, local l, peak g), where:\n"
          "\t p     - value just before starting of item's execution;\n"
          "\t n     - value just after end of item's execution;\n"
          "\t [+-c] - difference between n and p;\n"
          "\t l     - temporary usage of memory during item's execution;\n"
          "\t g     - global peak of the value during program's execution.\n\n"
          "\tChunks are items allocated in a pool."
          " If there is no pool with a free chunk upon chunk allocation request,\n"
          "\tthen new pool is allocated on the heap (that causes increase of number of allocated heap bytes).\n\n");
}

static void
interp_mem_get_stats (mem_heap_stats_t *out_heap_stats_p,
                      mem_pools_stats_t *out_pool_stats_p,
                      bool reset_peak_before,
                      bool reset_peak_after)
{
  if (likely (!interp_mem_stats_enabled))
  {
    return;
  }

  /* Requesting to free as much memory as we currently can */
  ecma_try_to_give_back_some_memory (MEM_TRY_GIVE_MEMORY_BACK_SEVERITY_CRITICAL);

  if (reset_peak_before)
  {
    mem_heap_stats_reset_peak ();
    mem_pools_stats_reset_peak ();
  }

  mem_heap_get_stats (out_heap_stats_p);
  mem_pools_get_stats (out_pool_stats_p);

  if (reset_peak_after)
  {
    mem_heap_stats_reset_peak ();
    mem_pools_stats_reset_peak ();
  }
}

static void
interp_mem_stats_context_enter (int_data_t *int_data_p,
                                opcode_counter_t block_position)
{
  if (likely (!interp_mem_stats_enabled))
  {
    return;
  }

  const uint32_t indentation = JERRY_MIN (interp_mem_stats_print_indentation,
                                          INTERP_MEM_PRINT_INDENTATION_MAX);

  char indent_prefix[INTERP_MEM_PRINT_INDENTATION_MAX + 2];
  memset (indent_prefix, ' ', sizeof (indent_prefix));
  indent_prefix[indentation] = '|';
  indent_prefix[indentation + 1] = '\0';

  int_data_p->context_peak_allocated_heap_bytes = 0;
  int_data_p->context_peak_waste_heap_bytes = 0;
  int_data_p->context_peak_pools_count = 0;
  int_data_p->context_peak_allocated_pool_chunks = 0;

  interp_mem_get_stats (&int_data_p->heap_stats_context_enter,
                        &int_data_p->pools_stats_context_enter,
                        false, false);

  printf ("\n%s--- Beginning interpretation of a block at position %u ---\n"
          "%s Allocated heap bytes:  %5u\n"
          "%s Waste heap bytes:      %5u\n"
          "%s Pools:                 %5u\n"
          "%s Allocated pool chunks: %5u\n\n",
          indent_prefix, (uint32_t) block_position,
          indent_prefix, (uint32_t) int_data_p->heap_stats_context_enter.allocated_bytes,
          indent_prefix, (uint32_t) int_data_p->heap_stats_context_enter.waste_bytes,
          indent_prefix, (uint32_t) int_data_p->pools_stats_context_enter.pools_count,
          indent_prefix, (uint32_t) int_data_p->pools_stats_context_enter.allocated_chunks);
}

static void
interp_mem_stats_context_exit (int_data_t *int_data_p,
                               opcode_counter_t block_position)
{
  if (likely (!interp_mem_stats_enabled))
  {
    return;
  }

  const uint32_t indentation = JERRY_MIN (interp_mem_stats_print_indentation,
                                          INTERP_MEM_PRINT_INDENTATION_MAX);

  char indent_prefix[INTERP_MEM_PRINT_INDENTATION_MAX + 2];
  memset (indent_prefix, ' ', sizeof (indent_prefix));
  indent_prefix[indentation] = '|';
  indent_prefix[indentation + 1] = '\0';

  mem_heap_stats_t heap_stats_context_exit;
  mem_pools_stats_t pools_stats_context_exit;

  interp_mem_get_stats (&heap_stats_context_exit,
                        &pools_stats_context_exit,
                        false, true);

  int_data_p->context_peak_allocated_heap_bytes -= JERRY_MAX (int_data_p->heap_stats_context_enter.allocated_bytes,
                                                              heap_stats_context_exit.allocated_bytes);
  int_data_p->context_peak_waste_heap_bytes -= JERRY_MAX (int_data_p->heap_stats_context_enter.waste_bytes,
                                                          heap_stats_context_exit.waste_bytes);
  int_data_p->context_peak_pools_count -= JERRY_MAX (int_data_p->pools_stats_context_enter.pools_count,
                                                     pools_stats_context_exit.pools_count);
  int_data_p->context_peak_allocated_pool_chunks -= JERRY_MAX (int_data_p->pools_stats_context_enter.allocated_chunks,
                                                               pools_stats_context_exit.allocated_chunks);

  printf ("%sAllocated heap bytes in the context:  %5u -> %5u (%+5d, local %5u, peak %5u)\n",
          indent_prefix,
          (uint32_t) int_data_p->heap_stats_context_enter.allocated_bytes,
          (uint32_t) heap_stats_context_exit.allocated_bytes,
          (uint32_t) (heap_stats_context_exit.allocated_bytes - int_data_p->heap_stats_context_enter.allocated_bytes),
          (uint32_t) int_data_p->context_peak_allocated_heap_bytes,
          (uint32_t) heap_stats_context_exit.global_peak_allocated_bytes);

  printf ("%sWaste heap bytes in the context:      %5u -> %5u (%+5d, local %5u, peak %5u)\n",
          indent_prefix,
          (uint32_t) int_data_p->heap_stats_context_enter.waste_bytes,
          (uint32_t) heap_stats_context_exit.waste_bytes,
          (uint32_t) (heap_stats_context_exit.waste_bytes - int_data_p->heap_stats_context_enter.waste_bytes),
          (uint32_t) int_data_p->context_peak_waste_heap_bytes,
          (uint32_t) heap_stats_context_exit.global_peak_waste_bytes);

  printf ("%sPools count in the context:           %5u -> %5u (%+5d, local %5u, peak %5u)\n",
          indent_prefix,
          (uint32_t) int_data_p->pools_stats_context_enter.pools_count,
          (uint32_t) pools_stats_context_exit.pools_count,
          (uint32_t) (pools_stats_context_exit.pools_count - int_data_p->pools_stats_context_enter.pools_count),
          (uint32_t) int_data_p->context_peak_pools_count,
          (uint32_t) pools_stats_context_exit.global_peak_pools_count);

  printf ("%sAllocated pool chunks in the context: %5u -> %5u (%+5d, local %5u, peak %5u)\n",
          indent_prefix,
          (uint32_t) int_data_p->pools_stats_context_enter.allocated_chunks,
          (uint32_t) pools_stats_context_exit.allocated_chunks,
          (uint32_t) (pools_stats_context_exit.allocated_chunks -
                      int_data_p->pools_stats_context_enter.allocated_chunks),
          (uint32_t) int_data_p->context_peak_allocated_pool_chunks,
          (uint32_t) pools_stats_context_exit.global_peak_allocated_chunks);

  printf ("\n%s--- End of interpretation of a block at position %u ---\n\n",
          indent_prefix, (uint32_t) block_position);
}

static void
interp_mem_stats_opcode_enter (const opcode_t *opcodes_p,
                               opcode_counter_t opcode_position,
                               mem_heap_stats_t *out_heap_stats_p,
                               mem_pools_stats_t *out_pools_stats_p)
{
  if (likely (!interp_mem_stats_enabled))
  {
    return;
  }

  const uint32_t indentation = JERRY_MIN (interp_mem_stats_print_indentation,
                                          INTERP_MEM_PRINT_INDENTATION_MAX);

  char indent_prefix[INTERP_MEM_PRINT_INDENTATION_MAX + 2];
  memset (indent_prefix, ' ', sizeof (indent_prefix));
  indent_prefix[indentation] = '|';
  indent_prefix[indentation + 1] = '\0';

  interp_mem_get_stats (out_heap_stats_p,
                        out_pools_stats_p,
                        true, false);

  opcode_t opcode = vm_get_opcode (opcodes_p, opcode_position);

  printf ("%s-- Opcode: %s (position %u) --\n",
          indent_prefix, __op_names[opcode.op_idx], (uint32_t) opcode_position);

  interp_mem_stats_print_indentation += INTERP_MEM_PRINT_INDENTATION_STEP;
}

static void
interp_mem_stats_opcode_exit (int_data_t *int_data_p,
                              opcode_counter_t opcode_position,
                              mem_heap_stats_t *heap_stats_before_p,
                              mem_pools_stats_t *pools_stats_before_p)
{
  if (likely (!interp_mem_stats_enabled))
  {
    return;
  }

  interp_mem_stats_print_indentation -= INTERP_MEM_PRINT_INDENTATION_STEP;

  const uint32_t indentation = JERRY_MIN (interp_mem_stats_print_indentation,
                                          INTERP_MEM_PRINT_INDENTATION_MAX);

  char indent_prefix[INTERP_MEM_PRINT_INDENTATION_MAX + 2];
  memset (indent_prefix, ' ', sizeof (indent_prefix));
  indent_prefix[indentation] = '|';
  indent_prefix[indentation + 1] = '\0';

  mem_heap_stats_t heap_stats_after;
  mem_pools_stats_t pools_stats_after;

  interp_mem_get_stats (&heap_stats_after,
                        &pools_stats_after,
                        false, true);

  int_data_p->context_peak_allocated_heap_bytes = JERRY_MAX (int_data_p->context_peak_allocated_heap_bytes,
                                                             heap_stats_after.allocated_bytes);
  int_data_p->context_peak_waste_heap_bytes = JERRY_MAX (int_data_p->context_peak_waste_heap_bytes,
                                                         heap_stats_after.waste_bytes);
  int_data_p->context_peak_pools_count = JERRY_MAX (int_data_p->context_peak_pools_count,
                                                    pools_stats_after.pools_count);
  int_data_p->context_peak_allocated_pool_chunks = JERRY_MAX (int_data_p->context_peak_allocated_pool_chunks,
                                                              pools_stats_after.allocated_chunks);

  opcode_t opcode = vm_get_opcode (int_data_p->opcodes_p, opcode_position);

  printf ("%s Allocated heap bytes:  %5u -> %5u (%+5d, local %5u, peak %5u)\n",
          indent_prefix,
          (uint32_t) heap_stats_before_p->allocated_bytes,
          (uint32_t) heap_stats_after.allocated_bytes,
          (uint32_t) (heap_stats_after.allocated_bytes - heap_stats_before_p->allocated_bytes),
          (uint32_t) (heap_stats_after.peak_allocated_bytes - JERRY_MAX (heap_stats_before_p->allocated_bytes,
                                                                         heap_stats_after.allocated_bytes)),
          (uint32_t) heap_stats_after.global_peak_allocated_bytes);

  if (heap_stats_before_p->waste_bytes != heap_stats_after.waste_bytes)
  {
    printf ("%s Waste heap bytes:      %5u -> %5u (%+5d, local %5u, peak %5u)\n",
            indent_prefix,
            (uint32_t) heap_stats_before_p->waste_bytes,
            (uint32_t) heap_stats_after.waste_bytes,
            (uint32_t) (heap_stats_after.waste_bytes - heap_stats_before_p->waste_bytes),
            (uint32_t) (heap_stats_after.peak_waste_bytes - JERRY_MAX (heap_stats_before_p->waste_bytes,
                                                                       heap_stats_after.waste_bytes)),
            (uint32_t) heap_stats_after.global_peak_waste_bytes);
  }

  if (pools_stats_before_p->pools_count != pools_stats_after.pools_count)
  {
    printf ("%s Pools:                 %5u -> %5u (%+5d, local %5u, peak %5u)\n",
            indent_prefix,
            (uint32_t) pools_stats_before_p->pools_count,
            (uint32_t) pools_stats_after.pools_count,
            (uint32_t) (pools_stats_after.pools_count - pools_stats_before_p->pools_count),
            (uint32_t) (pools_stats_after.peak_pools_count - JERRY_MAX (pools_stats_before_p->pools_count,
                                                                        pools_stats_after.pools_count)),
            (uint32_t) pools_stats_after.global_peak_pools_count);
  }

  if (pools_stats_before_p->allocated_chunks != pools_stats_after.allocated_chunks)
  {
    printf ("%s Allocated pool chunks: %5u -> %5u (%+5d, local %5u, peak %5u)\n",
            indent_prefix,
            (uint32_t) pools_stats_before_p->allocated_chunks,
            (uint32_t) pools_stats_after.allocated_chunks,
            (uint32_t) (pools_stats_after.allocated_chunks - pools_stats_before_p->allocated_chunks),
            (uint32_t) (pools_stats_after.peak_allocated_chunks - JERRY_MAX (pools_stats_before_p->allocated_chunks,
                                                                             pools_stats_after.allocated_chunks)),
            (uint32_t) pools_stats_after.global_peak_allocated_chunks);
  }

  printf ("%s-- End of execution of opcode %s (position %u) --\n\n",
          indent_prefix, __op_names[opcode.op_idx], opcode_position);
}
#endif /* MEM_STATS */

/**
 * Initialize interpreter.
 */
void
vm_init (const opcode_t *program_p, /**< pointer to byte-code program */
         bool dump_mem_stats) /** dump per-opcode memory usage change statistics */
{
#ifdef MEM_STATS
  interp_mem_stats_enabled = dump_mem_stats;
#else /* MEM_STATS */
  JERRY_ASSERT (!dump_mem_stats);
#endif /* !MEM_STATS */

  JERRY_ASSERT (__program == NULL);

  __program = program_p;
} /* vm_init */

/**
 * Cleanup interpreter
 */
void
vm_finalize (void)
{
  __program = NULL;
} /* vm_finalize */

/**
 * Run global code
 */
jerry_completion_code_t
vm_run_global (void)
{
  JERRY_ASSERT (__program != NULL);
  JERRY_ASSERT (vm_top_context_p == NULL);

#ifdef MEM_STATS
  interp_mem_stats_print_legend ();
#endif /* MEM_STATS */

  bool is_strict = false;
  opcode_counter_t start_pos = 0;

  opcode_scope_code_flags_t scope_flags = vm_get_scope_flags (__program,
                                                              start_pos++);

  if (scope_flags & OPCODE_SCOPE_CODE_FLAGS_STRICT)
  {
    is_strict = true;
  }

  ecma_object_t *glob_obj_p = ecma_builtin_get (ECMA_BUILTIN_ID_GLOBAL);
  ecma_object_t *lex_env_p = ecma_get_global_environment ();

  ecma_completion_value_t completion = vm_run_from_pos (__program,
                                                        start_pos,
                                                        ecma_make_object_value (glob_obj_p),
                                                        lex_env_p,
                                                        is_strict,
                                                        false);

  jerry_completion_code_t ret_code;

  if (ecma_is_completion_value_return (completion))
  {
    JERRY_ASSERT (ecma_is_value_undefined (ecma_get_completion_value_value (completion)));

    ret_code = JERRY_COMPLETION_CODE_OK;
  }
  else
  {
    JERRY_ASSERT (ecma_is_completion_value_throw (completion));

    ret_code = JERRY_COMPLETION_CODE_UNHANDLED_EXCEPTION;
  }

  ecma_free_completion_value (completion);

  ecma_deref_object (glob_obj_p);
  ecma_deref_object (lex_env_p);

  JERRY_ASSERT (vm_top_context_p == NULL);

  return ret_code;
} /* vm_run_global */

/**
 * Run interpreter loop using specified context
 *
 * Note:
 *      The interpreter loop stops upon receiving completion value that is normal completion value.
 *
 * @return If the received completion value is not meta completion value (ECMA_COMPLETION_TYPE_META), then
 *          the completion value is returned as is;
 *         Otherwise - the completion value is discarded and normal empty completion value is returned.
 */
ecma_completion_value_t
vm_loop (int_data_t *int_data_p, /**< interpreter context */
         vm_run_scope_t *run_scope_p) /**< current run scope,
                                       *   or NULL - if there is no active run scope */
{
  ecma_completion_value_t completion;

#ifdef MEM_STATS
  mem_heap_stats_t heap_stats_before;
  mem_pools_stats_t pools_stats_before;

  memset (&heap_stats_before, 0, sizeof (heap_stats_before));
  memset (&pools_stats_before, 0, sizeof (pools_stats_before));
#endif /* MEM_STATS */

  while (true)
  {
    do
    {
      JERRY_ASSERT (run_scope_p == NULL
                    || (run_scope_p->start_oc <= int_data_p->pos
                        && int_data_p->pos <= run_scope_p->end_oc));

      const opcode_t *curr = &int_data_p->opcodes_p[int_data_p->pos];

#ifdef MEM_STATS
      const opcode_counter_t opcode_pos = int_data_p->pos;

      interp_mem_stats_opcode_enter (int_data_p->opcodes_p,
                                     opcode_pos,
                                     &heap_stats_before,
                                     &pools_stats_before);
#endif /* MEM_STATS */

      completion = __opfuncs[curr->op_idx] (*curr, int_data_p);

#ifdef CONFIG_VM_RUN_GC_AFTER_EACH_OPCODE
      ecma_gc_run ();
#endif /* CONFIG_VM_RUN_GC_AFTER_EACH_OPCODE */

#ifdef MEM_STATS
      interp_mem_stats_opcode_exit (int_data_p,
                                    opcode_pos,
                                    &heap_stats_before,
                                    &pools_stats_before);
#endif /* MEM_STATS */

      JERRY_ASSERT (!ecma_is_completion_value_normal (completion)
                    || ecma_is_completion_value_empty (completion));
    }
    while (ecma_is_completion_value_normal (completion));

    if (ecma_is_completion_value_jump (completion))
    {
      opcode_counter_t target = ecma_get_jump_target_from_completion_value (completion);

      /*
       * TODO:
       *      Implement instantiation of run scopes for global scope, functions and eval scope.
       *      Currently, correctness of jumps without run scope set is guaranteed through byte-code semantics.
       */
      if (run_scope_p == NULL /* if no run scope set */
          || (target >= run_scope_p->start_oc /* or target is within the current run scope */
              && target <= run_scope_p->end_oc))
      {
        int_data_p->pos = target;

        continue;
      }
    }

    if (ecma_is_completion_value_meta (completion))
    {
      completion = ecma_make_empty_completion_value ();
    }

    return completion;
  }
} /* vm_loop */

/**
 * Run the code, starting from specified opcode
 */
ecma_completion_value_t
vm_run_from_pos (const opcode_t *opcodes_p, /**< byte-code array */
                 opcode_counter_t start_pos, /**< identifier of starting opcode */
                 ecma_value_t this_binding_value, /**< value of 'ThisBinding' */
                 ecma_object_t *lex_env_p, /**< lexical environment to use */
                 bool is_strict, /**< is the code is strict mode code (ECMA-262 v5, 10.1.1) */
                 bool is_eval_code) /**< is the code is eval code (ECMA-262 v5, 10.1) */
{
  ecma_completion_value_t completion;

  const opcode_t *curr = &opcodes_p[start_pos];
  JERRY_ASSERT (curr->op_idx == __op__idx_reg_var_decl);

  const idx_t min_reg_num = curr->data.reg_var_decl.min;
  const idx_t max_reg_num = curr->data.reg_var_decl.max;
  JERRY_ASSERT (max_reg_num >= min_reg_num);

  const int32_t regs_num = max_reg_num - min_reg_num + 1;

  MEM_DEFINE_LOCAL_ARRAY (regs, regs_num, ecma_value_t);

  int_data_t int_data;
  int_data.opcodes_p = opcodes_p;
  int_data.pos = (opcode_counter_t) (start_pos + 1);
  int_data.this_binding = this_binding_value;
  int_data.lex_env_p = lex_env_p;
  int_data.is_strict = is_strict;
  int_data.is_eval_code = is_eval_code;
  int_data.is_call_in_direct_eval_form = false;
  int_data.min_reg_num = min_reg_num;
  int_data.max_reg_num = max_reg_num;
  int_data.tmp_num_p = ecma_alloc_number ();
  ecma_stack_add_frame (&int_data.stack_frame, regs, regs_num);

  int_data_t *prev_context_p = vm_top_context_p;
  vm_top_context_p = &int_data;

#ifdef MEM_STATS
  interp_mem_stats_context_enter (&int_data, start_pos);
#endif /* MEM_STATS */

  completion = vm_loop (&int_data, NULL);

  JERRY_ASSERT (ecma_is_completion_value_throw (completion)
                || ecma_is_completion_value_return (completion));

  vm_top_context_p = prev_context_p;

  ecma_stack_free_frame (&int_data.stack_frame);

  ecma_dealloc_number (int_data.tmp_num_p);

#ifdef MEM_STATS
  interp_mem_stats_context_exit (&int_data, start_pos);
#endif /* MEM_STATS */

  MEM_FINALIZE_LOCAL_ARRAY (regs);

  return completion;
} /* vm_run_from_pos */

/**
 * Get specified opcode from the program.
 */
opcode_t
vm_get_opcode (const opcode_t *opcodes_p, /**< byte-code array */
               opcode_counter_t counter) /**< opcode counter */
{
  return opcodes_p[ counter ];
} /* vm_get_opcode */

/**
 * Get scope code flags from opcode specified by opcode counter
 *
 * @return mask of scope code flags
 */
opcode_scope_code_flags_t
vm_get_scope_flags (const opcode_t *opcodes_p, /**< byte-code array */
                    opcode_counter_t counter) /**< opcode counter */
{
  opcode_t flags_opcode = vm_get_opcode (opcodes_p, counter);
  JERRY_ASSERT (flags_opcode.op_idx == __op__idx_meta
                && flags_opcode.data.meta.type == OPCODE_META_TYPE_SCOPE_CODE_FLAGS);
  return (opcode_scope_code_flags_t) flags_opcode.data.meta.data_1;
} /* vm_get_scope_flags */

/**
 * Check whether currently executed code is strict mode code
 *
 * @return true - current code is executed in strict mode,
 *         false - otherwise.
 */
bool
vm_is_strict_mode (void)
{
  JERRY_ASSERT (vm_top_context_p != NULL);

  return vm_top_context_p->is_strict;
} /* vm_is_strict_mode */

/**
 * Check whether currently performed call (on top of call-stack) is performed in form,
 * meeting conditions of 'Direct Call to Eval' (see also: ECMA-262 v5, 15.1.2.1.1)
 *
 * Warning:
 *         the function should only be called from implementation
 *         of built-in 'eval' routine of Global object
 *
 * @return true - currently performed call is performed through 'eval' identifier,
 *                without 'this' argument,
 *         false - otherwise.
 */
bool
vm_is_direct_eval_form_call (void)
{
  if (vm_top_context_p != NULL)
  {
    return vm_top_context_p->is_call_in_direct_eval_form;
  }
  else
  {
    /*
     * There is no any interpreter context, so call is performed not from a script.
     * This implies that the call is indirect.
     */
    return false;
  }
} /* vm_is_direct_eval_form_call */

/**
 * Get this binding of current execution context
 *
 * @return ecma-value
 */
ecma_value_t
vm_get_this_binding (void)
{
  JERRY_ASSERT (vm_top_context_p != NULL);

  return ecma_copy_value (vm_top_context_p->this_binding, true);
} /* vm_get_this_binding */

/**
 * Get top lexical environment (variable environment) of current execution context
 *
 * @return lexical environment
 */
ecma_object_t*
vm_get_lex_env (void)
{
  JERRY_ASSERT (vm_top_context_p != NULL);

  ecma_ref_object (vm_top_context_p->lex_env_p);

  return vm_top_context_p->lex_env_p;
} /* vm_get_lex_env */