/* jit-builtins.c -- Handling of builtin functions during JIT-compilation.
   Copyright (C) 2014 Free Software Foundation, Inc.

This file is part of GCC.

GCC 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, or (at your option) any later
version.

GCC 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 GCC; see the file COPYING3.  If not see
<http://www.gnu.org/licenses/>.  */

#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "opts.h"
#include "tree.h"
#include "target.h"

#include "jit-common.h"
#include "jit-builtins.h"
#include "jit-recording.h"

namespace gcc {

namespace jit {

namespace recording {

const char *const prefix = "__builtin_";
const size_t prefix_len = strlen (prefix);

/* Create "builtin_data", a const table of the data within builtins.def.  */
struct builtin_data
{
  const char *name;
  enum jit_builtin_type type;
  bool both_p;
  bool fallback_p;

  const char *get_asm_name () const
  {
    if (both_p && fallback_p)
      return name + prefix_len;
    else
      return name;
  }
};

#define DEF_BUILTIN(X, NAME, C, TYPE, LT, BOTH_P, FALLBACK_P, NA, AT, IM, COND)\
  {NAME, TYPE, BOTH_P, FALLBACK_P},
static const struct builtin_data builtin_data[] =
{
#include "builtins.def"
};
#undef DEF_BUILTIN

/* Helper function for find_builtin_by_name.  */

static bool
matches_builtin (const char *in_name,
		 const struct builtin_data& bd)
{
  const bool debug = 0;
  gcc_assert (bd.name);

  if (debug)
    fprintf (stderr, "seen builtin: %s\n", bd.name);

  if (0 == strcmp (bd.name, in_name))
    {
      return true;
    }

  if (bd.both_p)
    {
      /* Then the macros in builtins.def gave a "__builtin_"
	 prefix to bd.name, but we should also recognize the form
	 without the prefix.  */
      gcc_assert (0 == strncmp (bd.name, prefix, prefix_len));
      if (debug)
	fprintf (stderr, "testing without prefix as: %s\n",
		 bd.name + prefix_len);
      if (0 == strcmp (bd.name + prefix_len, in_name))
	{
	  return true;
	}
    }

  return false;
}

/* Locate the built-in function that matches name IN_NAME,
   writing the result to OUT_ID and returning true if found,
   or returning false if not found.  */

static bool
find_builtin_by_name (const char *in_name,
		      enum built_in_function *out_id)
{
  /* Locate builtin.  This currently works by performing repeated
     strcmp against every possible candidate, which is likely to
     inefficient.

     We start at index 1 to skip the initial entry (BUILT_IN_NONE), which
     has a NULL name.  */
  for (unsigned int i = 1;
       i < sizeof (builtin_data) / sizeof (builtin_data[0]);
       i++)
    {
      const struct builtin_data& bd = builtin_data[i];
      if (matches_builtin (in_name, bd))
	{
	  /* Found a match.  */
	  *out_id = static_cast<enum built_in_function> (i);
	  return true;
	}
    }

  /* Not found.  */
  return false;
}

// class builtins_manager

/* Constructor for gcc::jit::recording::builtins_manager.  */

builtins_manager::builtins_manager (context *ctxt)
  : m_ctxt (ctxt)
{
  memset (m_types, 0, sizeof (m_types));
  memset (m_builtin_functions, 0, sizeof (m_builtin_functions));
}

/* Locate a builtin function by name.
   Create a recording::function of the appropriate type, reusing them
   if they've already been seen.  */

function *
builtins_manager::get_builtin_function (const char *name)
{
  enum built_in_function builtin_id;
  if (!find_builtin_by_name (name, &builtin_id))
    {
      m_ctxt->add_error (NULL, "builtin \"%s\" not found", name);
      return NULL;
    }

  gcc_assert (builtin_id >= 0);
  gcc_assert (builtin_id < END_BUILTINS);

  /* Lazily build the functions, caching them so that repeated calls for
     the same id on a context give back the same object.  */
  if (!m_builtin_functions[builtin_id])
    {
      m_builtin_functions[builtin_id] = make_builtin_function (builtin_id);
      m_ctxt->record (m_builtin_functions[builtin_id]);
    }

  return m_builtin_functions[builtin_id];
}

/* Create the recording::function for a given builtin function, by ID.  */

function *
builtins_manager::make_builtin_function (enum built_in_function builtin_id)
{
  const struct builtin_data& bd = builtin_data[builtin_id];
  enum jit_builtin_type type_id = bd.type;
  function_type *func_type = get_type (type_id)->as_a_function_type ();
  if (!func_type)
    return NULL;

  vec<type *> param_types = func_type->get_param_types ();
  recording::param **params = new recording::param *[param_types.length ()];

  int i;
  type *param_type;
  FOR_EACH_VEC_ELT (param_types, i, param_type)
    {
      char buf[16];
      snprintf (buf, 16, "arg%d", i);
      params[i] = m_ctxt->new_param (NULL,
				     param_type,
				     buf);
    }
  const char *asm_name = bd.get_asm_name ();
  function *result =
    new function (m_ctxt,
		  NULL,
		  GCC_JIT_FUNCTION_IMPORTED, // FIXME
		  func_type->get_return_type (),
		  m_ctxt->new_string (asm_name),
		  param_types.length (),
		  params,
		  func_type->is_variadic (),
		  builtin_id);
  delete[] params;
  return result;
}

/* Get the recording::type for a given type of builtin function,
   by ID, creating it if it doesn't already exist.  */

type *
builtins_manager::get_type (enum jit_builtin_type type_id)
{
  if (!m_types[type_id])
    m_types[type_id] = make_type (type_id);
  return m_types[type_id];
}

/* Create the recording::type for a given type of builtin function.  */

type *
builtins_manager::make_type (enum jit_builtin_type type_id)
{
  /* Use builtin-types.def to construct a switch statement, with each
     case deferring to one of the methods below:
       - DEF_PRIMITIVE_TYPE is handled as a call to make_primitive_type.
       - the various DEF_FUNCTION_TYPE_n are handled by variadic calls
	 to make_fn_type.
       - similarly for DEF_FUNCTION_TYPE_VAR_n, but setting the
	"is_variadic" argument.
       - DEF_POINTER_TYPE is handled by make_ptr_type.
     That should handle everything, but just in case we also suppy a
     gcc_unreachable default clause.  */
  switch (type_id)
    {
#define DEF_PRIMITIVE_TYPE(ENUM, VALUE) \
      case ENUM: return make_primitive_type (ENUM);
#define DEF_FUNCTION_TYPE_0(ENUM, RETURN) \
      case ENUM: return make_fn_type (ENUM, RETURN, 0, 0);
#define DEF_FUNCTION_TYPE_1(ENUM, RETURN, ARG1) \
      case ENUM: return make_fn_type (ENUM, RETURN, 0, 1, ARG1);
#define DEF_FUNCTION_TYPE_2(ENUM, RETURN, ARG1, ARG2) \
      case ENUM: return make_fn_type (ENUM, RETURN, 0, 2, ARG1, ARG2);
#define DEF_FUNCTION_TYPE_3(ENUM, RETURN, ARG1, ARG2, ARG3) \
      case ENUM: return make_fn_type (ENUM, RETURN, 0, 3, ARG1, ARG2, ARG3);
#define DEF_FUNCTION_TYPE_4(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4) \
      case ENUM: return make_fn_type (ENUM, RETURN, 0, 4, ARG1, ARG2, ARG3, ARG4);
#define DEF_FUNCTION_TYPE_5(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5)	\
      case ENUM: return make_fn_type (ENUM, RETURN, 0, 5, ARG1, ARG2, ARG3, ARG4, ARG5);
#define DEF_FUNCTION_TYPE_6(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5, \
			    ARG6)					\
      case ENUM: return make_fn_type (ENUM, RETURN, 0, 6, ARG1, ARG2, ARG3, ARG4, ARG5, ARG6);
#define DEF_FUNCTION_TYPE_7(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5, \
			    ARG6, ARG7)					\
      case ENUM: return make_fn_type (ENUM, RETURN, 0, 7, ARG1, ARG2, ARG3, ARG4, ARG5, ARG6, ARG7);
#define DEF_FUNCTION_TYPE_8(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5, \
			    ARG6, ARG7, ARG8)				\
      case ENUM: return make_fn_type (ENUM, RETURN, 0, 8, ARG1, ARG2, ARG3, ARG4, ARG5, ARG6, \
				      ARG7, ARG8);
#define DEF_FUNCTION_TYPE_VAR_0(ENUM, RETURN) \
      case ENUM: return make_fn_type (ENUM, RETURN, 1, 0);
#define DEF_FUNCTION_TYPE_VAR_1(ENUM, RETURN, ARG1) \
      case ENUM: return make_fn_type (ENUM, RETURN, 1, 1, ARG1);
#define DEF_FUNCTION_TYPE_VAR_2(ENUM, RETURN, ARG1, ARG2) \
      case ENUM: return make_fn_type (ENUM, RETURN, 1, 2, ARG1, ARG2);
#define DEF_FUNCTION_TYPE_VAR_3(ENUM, RETURN, ARG1, ARG2, ARG3) \
      case ENUM: return make_fn_type (ENUM, RETURN, 1, 3, ARG1, ARG2, ARG3);
#define DEF_FUNCTION_TYPE_VAR_4(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4) \
      case ENUM: return make_fn_type (ENUM, RETURN, 1, 4, ARG1, ARG2, ARG3, ARG4);
#define DEF_FUNCTION_TYPE_VAR_5(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5) \
      case ENUM: return make_fn_type (ENUM, RETURN, 1, 5, ARG1, ARG2, ARG3, ARG4, ARG5);
#define DEF_POINTER_TYPE(ENUM, TYPE) \
      case ENUM: return make_ptr_type (ENUM, TYPE);

#include "builtin-types.def"

#undef DEF_PRIMITIVE_TYPE
#undef DEF_FUNCTION_TYPE_1
#undef DEF_FUNCTION_TYPE_2
#undef DEF_FUNCTION_TYPE_3
#undef DEF_FUNCTION_TYPE_4
#undef DEF_FUNCTION_TYPE_5
#undef DEF_FUNCTION_TYPE_6
#undef DEF_FUNCTION_TYPE_VAR_0
#undef DEF_FUNCTION_TYPE_VAR_1
#undef DEF_FUNCTION_TYPE_VAR_2
#undef DEF_FUNCTION_TYPE_VAR_3
#undef DEF_FUNCTION_TYPE_VAR_4
#undef DEF_FUNCTION_TYPE_VAR_5
#undef DEF_POINTER_TYPE

    default:
      gcc_unreachable ();
    }
}

/* Create the recording::type for a given primitive type within the
   builtin system.

   Only some types are currently supported.  */

type*
builtins_manager::make_primitive_type (enum jit_builtin_type type_id)
{
  switch (type_id)
    {
    default:
      // only some of these types are implemented so far:
      m_ctxt->add_error (NULL,
			 "unimplemented primitive type for builtin: %d", type_id);
      return NULL;

    case BT_VOID: return m_ctxt->get_type (GCC_JIT_TYPE_VOID);
    case BT_BOOL: return m_ctxt->get_type (GCC_JIT_TYPE_BOOL);
    case BT_INT: return m_ctxt->get_type (GCC_JIT_TYPE_INT);
    case BT_UINT: return m_ctxt->get_type (GCC_JIT_TYPE_UNSIGNED_INT);
    case BT_LONG: return m_ctxt->get_type (GCC_JIT_TYPE_LONG);
    case BT_ULONG: return m_ctxt->get_type (GCC_JIT_TYPE_UNSIGNED_LONG);
    case BT_LONGLONG: return m_ctxt->get_type (GCC_JIT_TYPE_LONG_LONG);
    case BT_ULONGLONG:
      return m_ctxt->get_type (GCC_JIT_TYPE_UNSIGNED_LONG_LONG);
    // case BT_INT128:
    // case BT_UINT128:
    // case BT_INTMAX:
    // case BT_UINTMAX:
    case BT_UINT16: return m_ctxt->get_int_type (2, false);
    case BT_UINT32: return m_ctxt->get_int_type (4, false);
    case BT_UINT64: return m_ctxt->get_int_type (8, false);
    // case BT_WORD:
    // case BT_UNWINDWORD:
    case BT_FLOAT: return m_ctxt->get_type (GCC_JIT_TYPE_FLOAT);
    case BT_DOUBLE: return m_ctxt->get_type (GCC_JIT_TYPE_DOUBLE);
    case BT_LONGDOUBLE: return m_ctxt->get_type (GCC_JIT_TYPE_LONG_DOUBLE);
    // case BT_COMPLEX_FLOAT:
    // case BT_COMPLEX_DOUBLE:
    // case BT_COMPLEX_LONGDOUBLE:
    case BT_PTR: return m_ctxt->get_type (GCC_JIT_TYPE_VOID_PTR);
    case BT_FILEPTR: return m_ctxt->get_type (GCC_JIT_TYPE_FILE_PTR);
    // case BT_CONST:
    // case BT_VOLATILE_PTR:
    // case BT_CONST_VOLATILE_PTR:
    // case BT_PTRMODE:
    // case BT_INT_PTR:
    // case BT_FLOAT_PTR:
    // case BT_DOUBLE_PTR:
    // case BT_CONST_DOUBLE_PTR:
    // case BT_LONGDOUBLE_PTR:
    // case BT_PID:
    // case BT_SIZE:
    // case BT_SSIZE:
    // case BT_WINT:
    // case BT_STRING:
    case BT_CONST_STRING: return m_ctxt->get_type (GCC_JIT_TYPE_CONST_CHAR_PTR);
    // case BT_DFLOAT32:
    // case BT_DFLOAT64:
    // case BT_DFLOAT128:
    // case BT_DFLOAT32_PTR:
    // case BT_DFLOAT64_PTR:
    // case BT_DFLOAT128_PTR:
    // case BT_VALIST_REF:
    // case BT_VALIST_ARG:
    // case BT_I1:
    // case BT_I2:
    // case BT_I4:
    // case BT_I8:
    // case BT_I16:
    }
}

/* Create the recording::function_type for a given function type
   signature.  */

function_type *
builtins_manager::make_fn_type (enum jit_builtin_type,
				enum jit_builtin_type return_type_id,
				bool is_variadic,
				int num_args, ...)
{
  va_list list;
  int i;
  type **param_types = new type *[num_args];
  type *return_type = NULL;
  function_type *result = NULL;

  va_start (list, num_args);
  for (i = 0; i < num_args; ++i)
    {
      enum jit_builtin_type arg_type_id =
	(enum jit_builtin_type) va_arg (list, int);
      param_types[i] = get_type (arg_type_id);
      if (!param_types[i])
	goto error;
    }
  va_end (list);

  return_type = get_type (return_type_id);
  if (!return_type)
    goto error;

  result = new function_type (m_ctxt,
			      return_type,
			      num_args,
			      param_types,
			      is_variadic);

 error:
  delete[] param_types;
  return result;
}

/* Handler for DEF_POINTER_TYPE within builtins_manager::make_type.  */

type *
builtins_manager::make_ptr_type (enum jit_builtin_type,
				 enum jit_builtin_type other_type_id)
{
  type *base_type = get_type (other_type_id);
  return base_type->get_pointer ();
}

} // namespace recording
} // namespace jit
} // namespace gcc