PR jit/64020: Fixes to handling of builtins

[official-gcc.git] / gcc / jit / jit-playback.c

/* Internals of libgccjit: classes for playing back recorded API calls.
   Copyright (C) 2013-2014 Free Software Foundation, Inc.
   Contributed by David Malcolm <dmalcolm@redhat.com>.

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 "hash-map.h"
#include "is-a.h"
#include "plugin-api.h"
#include "vec.h"
#include "hashtab.h"
#include "hash-set.h"
#include "machmode.h"
#include "tm.h"
#include "hard-reg-set.h"
#include "function.h"
#include "ipa-ref.h"
#include "dumpfile.h"
#include "cgraph.h"
#include "toplev.h"
#include "timevar.h"
#include "tree-cfg.h"
#include "target.h"
#include "convert.h"
#include "stringpool.h"
#include "stor-layout.h"
#include "print-tree.h"
#include "gimplify.h"
#include "gcc-driver-name.h"
#include "attribs.h"

#include "jit-common.h"
#include "jit-playback.h"
#include "jit-result.h"
#include "jit-builtins.h"


/* gcc::jit::playback::context::build_cast uses the convert.h API,
   which in turn requires the frontend to provide a "convert"
   function, apparently as a fallback.

   Hence we provide this dummy one, with the requirement that any casts
   are handled before reaching this.  */
extern tree convert (tree type, tree expr);

tree
convert (tree dst_type, tree expr)
{
  gcc_assert (gcc::jit::active_playback_ctxt);
  gcc::jit::active_playback_ctxt->add_error (NULL, "unhandled conversion");
  fprintf (stderr, "input expression:\n");
  debug_tree (expr);
  fprintf (stderr, "requested type:\n");
  debug_tree (dst_type);
  return error_mark_node;
}

namespace gcc {
namespace jit {

/**********************************************************************
 Playback.
 **********************************************************************/

/* The constructor for gcc::jit::playback::context.  */

playback::context::context (recording::context *ctxt)
  : m_recording_ctxt (ctxt),
    m_char_array_type_node (NULL),
    m_const_char_ptr (NULL)
{
  m_functions.create (0);
  m_source_files.create (0);
  m_cached_locations.create (0);
}

/* The destructor for gcc::jit::playback::context.  */

playback::context::~context ()
{
  if (get_bool_option (GCC_JIT_BOOL_OPTION_KEEP_INTERMEDIATES))
    fprintf (stderr, "intermediate files written to %s\n", m_path_tempdir);
  else
    {
      /* Clean up .s/.so and tempdir. */
      if (m_path_s_file)
        unlink (m_path_s_file);
      if (m_path_so_file)
        unlink (m_path_so_file);
      if (m_path_tempdir)
        rmdir (m_path_tempdir);
    }

  free (m_path_template);
  /* m_path_tempdir aliases m_path_template, or is NULL, so don't
     attempt to free it .  */
  free (m_path_c_file);
  free (m_path_s_file);
  free (m_path_so_file);
  m_functions.release ();
}

/* A playback::context can reference GC-managed pointers.  Mark them
   ("by hand", rather than by gengtype).

   This is called on the active playback context (if any) by the
   my_ggc_walker hook in the jit_root_table in dummy-frontend.c.  */

void
playback::context::
gt_ggc_mx ()
{
  int i;
  function *func;
  FOR_EACH_VEC_ELT (m_functions, i, func)
    {
      if (ggc_test_and_set_mark (func))
        func->gt_ggc_mx ();
    }
}

/* Given an enum gcc_jit_types value, get a "tree" type.  */

static tree
get_tree_node_for_type (enum gcc_jit_types type_)
{
  switch (type_)
    {
    case GCC_JIT_TYPE_VOID:
      return void_type_node;

    case GCC_JIT_TYPE_VOID_PTR:
      return ptr_type_node;

    case GCC_JIT_TYPE_BOOL:
      return boolean_type_node;

    case GCC_JIT_TYPE_CHAR:
      return char_type_node;
    case GCC_JIT_TYPE_SIGNED_CHAR:
      return signed_char_type_node;
    case GCC_JIT_TYPE_UNSIGNED_CHAR:
      return unsigned_char_type_node;

    case GCC_JIT_TYPE_SHORT:
      return short_integer_type_node;
    case GCC_JIT_TYPE_UNSIGNED_SHORT:
      return short_unsigned_type_node;

    case GCC_JIT_TYPE_CONST_CHAR_PTR:
      {
        tree const_char = build_qualified_type (char_type_node,
                                                TYPE_QUAL_CONST);
        return build_pointer_type (const_char);
      }

    case GCC_JIT_TYPE_INT:
      return integer_type_node;
    case GCC_JIT_TYPE_UNSIGNED_INT:
      return unsigned_type_node;

    case GCC_JIT_TYPE_LONG:
      return long_integer_type_node;
    case GCC_JIT_TYPE_UNSIGNED_LONG:
      return long_unsigned_type_node;

    case GCC_JIT_TYPE_LONG_LONG:
      return long_long_integer_type_node;
    case GCC_JIT_TYPE_UNSIGNED_LONG_LONG:
      return long_long_unsigned_type_node;

    case GCC_JIT_TYPE_FLOAT:
      return float_type_node;
    case GCC_JIT_TYPE_DOUBLE:
      return double_type_node;
    case GCC_JIT_TYPE_LONG_DOUBLE:
      return long_double_type_node;

    case GCC_JIT_TYPE_SIZE_T:
      return size_type_node;

    case GCC_JIT_TYPE_FILE_PTR:
      return fileptr_type_node;

    case GCC_JIT_TYPE_COMPLEX_FLOAT:
      return complex_float_type_node;
    case GCC_JIT_TYPE_COMPLEX_DOUBLE:
      return complex_double_type_node;
    case GCC_JIT_TYPE_COMPLEX_LONG_DOUBLE:
      return complex_long_double_type_node;
    }

  return NULL;
}

/* Construct a playback::type instance (wrapping a tree) for the given
   enum value.  */

playback::type *
playback::context::
get_type (enum gcc_jit_types type_)
{
  tree type_node = get_tree_node_for_type (type_);
  if (NULL == type_node)
    {
      add_error (NULL,
                 "unrecognized (enum gcc_jit_types) value: %i", type_);
      return NULL;
    }

  return new type (type_node);
}

/* Construct a playback::type instance (wrapping a tree) for the given
   array type.  */

playback::type *
playback::context::
new_array_type (playback::location *loc,
                playback::type *element_type,
                int num_elements)
{
  gcc_assert (element_type);

  tree t = build_array_type_nelts (element_type->as_tree (),
                                   num_elements);
  layout_type (t);

  if (loc)
    set_tree_location (t, loc);

  return new type (t);
}

/* Construct a playback::field instance (wrapping a tree).  */

playback::field *
playback::context::
new_field (location *loc,
           type *type,
           const char *name)
{
  gcc_assert (type);
  gcc_assert (name);

  /* compare with c/c-decl.c:grokfield and grokdeclarator.  */
  tree decl = build_decl (UNKNOWN_LOCATION, FIELD_DECL,
                          get_identifier (name), type->as_tree ());

  if (loc)
    set_tree_location (decl, loc);

  return new field (decl);
}

/* Construct a playback::compound_type instance (wrapping a tree).  */

playback::compound_type *
playback::context::
new_compound_type (location *loc,
                   const char *name,
                   bool is_struct) /* else is union */
{
  gcc_assert (name);

  /* Compare with c/c-decl.c: start_struct. */

  tree t = make_node (is_struct ? RECORD_TYPE : UNION_TYPE);
  TYPE_NAME (t) = get_identifier (name);
  TYPE_SIZE (t) = 0;

  if (loc)
    set_tree_location (t, loc);

  return new compound_type (t);
}

void
playback::compound_type::set_fields (const auto_vec<playback::field *> *fields)
{
  /* Compare with c/c-decl.c: finish_struct. */
  tree t = as_tree ();

  tree fieldlist = NULL;
  for (unsigned i = 0; i < fields->length (); i++)
    {
      field *f = (*fields)[i];
      DECL_CONTEXT (f->as_tree ()) = t;
      fieldlist = chainon (f->as_tree (), fieldlist);
    }
  fieldlist = nreverse (fieldlist);
  TYPE_FIELDS (t) = fieldlist;

  layout_type (t);
}

/* Construct a playback::type instance (wrapping a tree) for a function
   type.  */

playback::type *
playback::context::
new_function_type (type *return_type,
                   const auto_vec<type *> *param_types,
                   int is_variadic)
{
  int i;
  type *param_type;

  tree *arg_types = (tree *)xcalloc(param_types->length (), sizeof(tree*));

  FOR_EACH_VEC_ELT (*param_types, i, param_type)
    arg_types[i] = param_type->as_tree ();

  tree fn_type;
  if (is_variadic)
    fn_type =
      build_varargs_function_type_array (return_type->as_tree (),
                                         param_types->length (),
                                         arg_types);
  else
    fn_type = build_function_type_array (return_type->as_tree (),
                                         param_types->length (),
                                         arg_types);
  free (arg_types);

  return new type (fn_type);
}

/* Construct a playback::param instance (wrapping a tree).  */

playback::param *
playback::context::
new_param (location *loc,
           type *type,
           const char *name)
{
  gcc_assert (type);
  gcc_assert (name);
  tree inner = build_decl (UNKNOWN_LOCATION, PARM_DECL,
                           get_identifier (name), type->as_tree ());
  if (loc)
    set_tree_location (inner, loc);

  return new param (this, inner);
}

/* Construct a playback::function instance.  */

playback::function *
playback::context::
new_function (location *loc,
              enum gcc_jit_function_kind kind,
              type *return_type,
              const char *name,
              const auto_vec<param *> *params,
              int is_variadic,
              enum built_in_function builtin_id)
{
  int i;
  param *param;

  //can return_type be NULL?
  gcc_assert (name);

  tree *arg_types = (tree *)xcalloc(params->length (), sizeof(tree*));
  FOR_EACH_VEC_ELT (*params, i, param)
    arg_types[i] = TREE_TYPE (param->as_tree ());

  tree fn_type;
  if (is_variadic)
    fn_type = build_varargs_function_type_array (return_type->as_tree (),
                                                 params->length (), arg_types);
  else
    fn_type = build_function_type_array (return_type->as_tree (),
                                         params->length (), arg_types);
  free (arg_types);

  /* FIXME: this uses input_location: */
  tree fndecl = build_fn_decl (name, fn_type);

  if (loc)
    set_tree_location (fndecl, loc);

  tree resdecl = build_decl (UNKNOWN_LOCATION, RESULT_DECL,
                             NULL_TREE, return_type->as_tree ());
  DECL_ARTIFICIAL (resdecl) = 1;
  DECL_IGNORED_P (resdecl) = 1;
  DECL_RESULT (fndecl) = resdecl;

  if (builtin_id)
    {
      DECL_FUNCTION_CODE (fndecl) = builtin_id;
      gcc_assert (loc == NULL);
      DECL_SOURCE_LOCATION (fndecl) = BUILTINS_LOCATION;

      DECL_BUILT_IN_CLASS (fndecl) =
        builtins_manager::get_class (builtin_id);
      set_builtin_decl (builtin_id, fndecl,
                        builtins_manager::implicit_p (builtin_id));

      builtins_manager *bm = get_builtins_manager ();
      tree attrs = bm->get_attrs_tree (builtin_id);
      if (attrs)
        decl_attributes (&fndecl, attrs, ATTR_FLAG_BUILT_IN);
      else
        decl_attributes (&fndecl, NULL_TREE, 0);
    }

  if (kind != GCC_JIT_FUNCTION_IMPORTED)
    {
      tree param_decl_list = NULL;
      FOR_EACH_VEC_ELT (*params, i, param)
        {
          param_decl_list = chainon (param->as_tree (), param_decl_list);
        }

      /* The param list was created in reverse order; fix it: */
      param_decl_list = nreverse (param_decl_list);

      tree t;
      for (t = param_decl_list; t; t = DECL_CHAIN (t))
        {
          DECL_CONTEXT (t) = fndecl;
          DECL_ARG_TYPE (t) = TREE_TYPE (t);
        }

      /* Set it up on DECL_ARGUMENTS */
      DECL_ARGUMENTS(fndecl) = param_decl_list;
    }

  if (kind == GCC_JIT_FUNCTION_ALWAYS_INLINE)
    {
      DECL_DECLARED_INLINE_P (fndecl) = 1;

      /* Add attribute "always_inline": */
      DECL_ATTRIBUTES (fndecl) =
        tree_cons (get_identifier ("always_inline"),
                   NULL,
                   DECL_ATTRIBUTES (fndecl));
    }

  function *func = new function (this, fndecl, kind);
  m_functions.safe_push (func);
  return func;
}

/* Construct a playback::lvalue instance (wrapping a tree).  */

playback::lvalue *
playback::context::
new_global (location *loc,
            type *type,
            const char *name)
{
  gcc_assert (type);
  gcc_assert (name);
  tree inner = build_decl (UNKNOWN_LOCATION, VAR_DECL,
                           get_identifier (name),
                           type->as_tree ());
  TREE_PUBLIC (inner) = 1;
  DECL_COMMON (inner) = 1;
  DECL_EXTERNAL (inner) = 1;

  if (loc)
    set_tree_location (inner, loc);

  return new lvalue (this, inner);
}

/* Construct a playback::rvalue instance (wrapping a tree).  */

playback::rvalue *
playback::context::
new_rvalue_from_int (type *type,
                     int value)
{
  // FIXME: type-checking, or coercion?
  tree inner_type = type->as_tree ();
  if (INTEGRAL_TYPE_P (inner_type))
    {
      tree inner = build_int_cst (inner_type, value);
      return new rvalue (this, inner);
    }
  else
    {
      REAL_VALUE_TYPE real_value;
      real_from_integer (&real_value, VOIDmode, value, SIGNED);
      tree inner = build_real (inner_type, real_value);
      return new rvalue (this, inner);
    }
}

/* Construct a playback::rvalue instance (wrapping a tree).  */

playback::rvalue *
playback::context::
new_rvalue_from_double (type *type,
                        double value)
{
  // FIXME: type-checking, or coercion?
  tree inner_type = type->as_tree ();

  /* We have a "double", we want a REAL_VALUE_TYPE.

     real.c:real_from_target appears to require the representation to be
     split into 32-bit values, and then sent as an pair of host long
     ints.  */
  REAL_VALUE_TYPE real_value;
  union
  {
    double as_double;
    uint32_t as_uint32s[2];
  } u;
  u.as_double = value;
  long int as_long_ints[2];
  as_long_ints[0] = u.as_uint32s[0];
  as_long_ints[1] = u.as_uint32s[1];
  real_from_target (&real_value, as_long_ints, DFmode);
  tree inner = build_real (inner_type, real_value);
  return new rvalue (this, inner);
}

/* Construct a playback::rvalue instance (wrapping a tree).  */

playback::rvalue *
playback::context::
new_rvalue_from_ptr (type *type,
                     void *value)
{
  tree inner_type = type->as_tree ();
  /* FIXME: how to ensure we have a wide enough type?  */
  tree inner = build_int_cstu (inner_type, (unsigned HOST_WIDE_INT)value);
  return new rvalue (this, inner);
}

/* Construct a playback::rvalue instance (wrapping a tree).  */

playback::rvalue *
playback::context::
new_string_literal (const char *value)
{
  tree t_str = build_string (strlen (value), value);
  gcc_assert (m_char_array_type_node);
  TREE_TYPE (t_str) = m_char_array_type_node;

  /* Convert to (const char*), loosely based on
     c/c-typeck.c: array_to_pointer_conversion,
     by taking address of start of string.  */
  tree t_addr = build1 (ADDR_EXPR, m_const_char_ptr, t_str);

  return new rvalue (this, t_addr);
}

/* Coerce a tree expression into a boolean tree expression.  */

tree
playback::context::
as_truth_value (tree expr, location *loc)
{
  /* Compare to c-typeck.c:c_objc_common_truthvalue_conversion */
  tree typed_zero = fold_build1 (CONVERT_EXPR,
                                 TREE_TYPE (expr),
                                 integer_zero_node);
  if (loc)
    set_tree_location (typed_zero, loc);

  expr = build2 (NE_EXPR, integer_type_node, expr, typed_zero);
  if (loc)
    set_tree_location (expr, loc);

  return expr;
}

/* Construct a playback::rvalue instance (wrapping a tree) for a
   unary op.  */

playback::rvalue *
playback::context::
new_unary_op (location *loc,
              enum gcc_jit_unary_op op,
              type *result_type,
              rvalue *a)
{
  // FIXME: type-checking, or coercion?
  enum tree_code inner_op;

  gcc_assert (result_type);
  gcc_assert (a);

  tree node = a->as_tree ();
  tree inner_result = NULL;

  switch (op)
    {
    default:
      add_error (loc, "unrecognized (enum gcc_jit_unary_op) value: %i", op);
      return NULL;

    case GCC_JIT_UNARY_OP_MINUS:
      inner_op = NEGATE_EXPR;
      break;

    case GCC_JIT_UNARY_OP_BITWISE_NEGATE:
      inner_op = BIT_NOT_EXPR;
      break;

    case GCC_JIT_UNARY_OP_LOGICAL_NEGATE:
      node = as_truth_value (node, loc);
      inner_result = invert_truthvalue (node);
      if (loc)
        set_tree_location (inner_result, loc);
      return new rvalue (this, inner_result);
    }

  inner_result = build1 (inner_op,
                         result_type->as_tree (),
                         node);
  if (loc)
    set_tree_location (inner_result, loc);

  return new rvalue (this, inner_result);
}

/* Construct a playback::rvalue instance (wrapping a tree) for a
   binary op.  */

playback::rvalue *
playback::context::
new_binary_op (location *loc,
               enum gcc_jit_binary_op op,
               type *result_type,
               rvalue *a, rvalue *b)
{
  // FIXME: type-checking, or coercion?
  enum tree_code inner_op;

  gcc_assert (result_type);
  gcc_assert (a);
  gcc_assert (b);

  tree node_a = a->as_tree ();
  tree node_b = b->as_tree ();

  switch (op)
    {
    default:
      add_error (loc, "unrecognized (enum gcc_jit_binary_op) value: %i", op);
      return NULL;

    case GCC_JIT_BINARY_OP_PLUS:
      inner_op = PLUS_EXPR;
      break;

    case GCC_JIT_BINARY_OP_MINUS:
      inner_op = MINUS_EXPR;
      break;

    case GCC_JIT_BINARY_OP_MULT:
      inner_op = MULT_EXPR;
      break;

    case GCC_JIT_BINARY_OP_DIVIDE:
      if (FLOAT_TYPE_P (result_type->as_tree ()))
        /* Floating-point division: */
        inner_op = RDIV_EXPR;
      else
        /* Truncating to zero: */
        inner_op = TRUNC_DIV_EXPR;
      break;

    case GCC_JIT_BINARY_OP_MODULO:
      inner_op = TRUNC_MOD_EXPR;
      break;

    case GCC_JIT_BINARY_OP_BITWISE_AND:
      inner_op = BIT_AND_EXPR;
      break;

    case GCC_JIT_BINARY_OP_BITWISE_XOR:
      inner_op = BIT_XOR_EXPR;
      break;

    case GCC_JIT_BINARY_OP_BITWISE_OR:
      inner_op = BIT_IOR_EXPR;
      break;

    case GCC_JIT_BINARY_OP_LOGICAL_AND:
      node_a = as_truth_value (node_a, loc);
      node_b = as_truth_value (node_b, loc);
      inner_op = TRUTH_ANDIF_EXPR;
      break;

    case GCC_JIT_BINARY_OP_LOGICAL_OR:
      node_a = as_truth_value (node_a, loc);
      node_b = as_truth_value (node_b, loc);
      inner_op = TRUTH_ORIF_EXPR;
      break;

    case GCC_JIT_BINARY_OP_LSHIFT:
      inner_op = LSHIFT_EXPR;
      break;

    case GCC_JIT_BINARY_OP_RSHIFT:
      inner_op = RSHIFT_EXPR;
      break;
    }

  tree inner_expr = build2 (inner_op,
                            result_type->as_tree (),
                            node_a,
                            node_b);
  if (loc)
    set_tree_location (inner_expr, loc);

  return new rvalue (this, inner_expr);
}

/* Construct a playback::rvalue instance (wrapping a tree) for a
   comparison.  */

playback::rvalue *
playback::context::
new_comparison (location *loc,
                enum gcc_jit_comparison op,
                rvalue *a, rvalue *b)
{
  // FIXME: type-checking, or coercion?
  enum tree_code inner_op;

  gcc_assert (a);
  gcc_assert (b);

  switch (op)
    {
    default:
      add_error (loc, "unrecognized (enum gcc_jit_comparison) value: %i", op);
      return NULL;

    case GCC_JIT_COMPARISON_EQ:
      inner_op = EQ_EXPR;
      break;
    case GCC_JIT_COMPARISON_NE:
      inner_op = NE_EXPR;
      break;
    case GCC_JIT_COMPARISON_LT:
      inner_op = LT_EXPR;
      break;
    case GCC_JIT_COMPARISON_LE:
      inner_op = LE_EXPR;
      break;
    case GCC_JIT_COMPARISON_GT:
      inner_op = GT_EXPR;
      break;
    case GCC_JIT_COMPARISON_GE:
      inner_op = GE_EXPR;
      break;
    }

  tree inner_expr = build2 (inner_op,
                            boolean_type_node,
                            a->as_tree (),
                            b->as_tree ());
  if (loc)
    set_tree_location (inner_expr, loc);
  return new rvalue (this, inner_expr);
}

/* Construct a playback::rvalue instance (wrapping a tree) for a
   function call.  */

playback::rvalue *
playback::context::
build_call (location *loc,
            tree fn_ptr,
            const auto_vec<rvalue *> *args)
{
  vec<tree, va_gc> *tree_args;
  vec_alloc (tree_args, args->length ());
  for (unsigned i = 0; i < args->length (); i++)
    tree_args->quick_push ((*args)[i]->as_tree ());

  if (loc)
    set_tree_location (fn_ptr, loc);

  tree fn = TREE_TYPE (fn_ptr);
  tree fn_type = TREE_TYPE (fn);
  tree return_type = TREE_TYPE (fn_type);

  return new rvalue (this,
                     build_call_vec (return_type,
                                     fn_ptr, tree_args));

  /* see c-typeck.c: build_function_call
     which calls build_function_call_vec

     which does lots of checking, then:
    result = build_call_array_loc (loc, TREE_TYPE (fntype),
                                   function, nargs, argarray);
    which is in tree.c
    (see also build_call_vec)
   */
}

/* Construct a playback::rvalue instance (wrapping a tree) for a
   call to a specific function.  */

playback::rvalue *
playback::context::
new_call (location *loc,
          function *func,
          const auto_vec<rvalue *> *args)
{
  tree fndecl;

  gcc_assert (func);

  fndecl = func->as_fndecl ();

  tree fntype = TREE_TYPE (fndecl);

  tree fn = build1 (ADDR_EXPR, build_pointer_type (fntype), fndecl);

  return build_call (loc, fn, args);
}

/* Construct a playback::rvalue instance (wrapping a tree) for a
   call through a function pointer.  */

playback::rvalue *
playback::context::
new_call_through_ptr (location *loc,
                      rvalue *fn_ptr,
                      const auto_vec<rvalue *> *args)
{
  gcc_assert (fn_ptr);
  tree t_fn_ptr = fn_ptr->as_tree ();

  return build_call (loc, t_fn_ptr, args);
}

/* Construct a tree for a cast.  */

tree
playback::context::build_cast (playback::location *loc,
                               playback::rvalue *expr,
                               playback::type *type_)
{
  /* For comparison, see:
     - c/c-typeck.c:build_c_cast
     - c/c-convert.c: convert
     - convert.h

     Only some kinds of cast are currently supported here.  */
  tree t_expr = expr->as_tree ();
  tree t_dst_type = type_->as_tree ();
  tree t_ret = NULL;
  t_ret = targetm.convert_to_type (t_dst_type, t_expr);
  if (t_ret)
      return t_ret;
  enum tree_code dst_code = TREE_CODE (t_dst_type);
  switch (dst_code)
    {
    case INTEGER_TYPE:
    case ENUMERAL_TYPE:
      t_ret = convert_to_integer (t_dst_type, t_expr);
      goto maybe_fold;

    case BOOLEAN_TYPE:
      /* Compare with c_objc_common_truthvalue_conversion and
         c_common_truthvalue_conversion. */
      /* For now, convert to: (t_expr != 0)  */
      t_ret = build2 (NE_EXPR, t_dst_type,
                      t_expr, integer_zero_node);
      goto maybe_fold;

    case REAL_TYPE:
      t_ret = convert_to_real (t_dst_type, t_expr);
      goto maybe_fold;

    case POINTER_TYPE:
      t_ret = build1 (NOP_EXPR, t_dst_type, t_expr);
      goto maybe_fold;

    default:
      add_error (loc, "couldn't handle cast during playback");
      fprintf (stderr, "input expression:\n");
      debug_tree (t_expr);
      fprintf (stderr, "requested type:\n");
      debug_tree (t_dst_type);
      return error_mark_node;

    maybe_fold:
      if (TREE_CODE (t_ret) != C_MAYBE_CONST_EXPR)
        t_ret = fold (t_ret);
      return t_ret;
    }
}

/* Construct a playback::rvalue instance (wrapping a tree) for a
   cast.  */

playback::rvalue *
playback::context::
new_cast (playback::location *loc,
          playback::rvalue *expr,
          playback::type *type_)
{

  tree t_cast = build_cast (loc, expr, type_);
  if (loc)
    set_tree_location (t_cast, loc);
  return new rvalue (this, t_cast);
}

/* Construct a playback::lvalue instance (wrapping a tree) for an
   array access.  */

playback::lvalue *
playback::context::
new_array_access (location *loc,
                  rvalue *ptr,
                  rvalue *index)
{
  gcc_assert (ptr);
  gcc_assert (index);

  /* For comparison, see:
       c/c-typeck.c: build_array_ref
       c-family/c-common.c: pointer_int_sum
  */
  tree t_ptr = ptr->as_tree ();
  tree t_index = index->as_tree ();
  tree t_type_ptr = TREE_TYPE (t_ptr);
  tree t_type_star_ptr = TREE_TYPE (t_type_ptr);

  if (TREE_CODE (t_type_ptr) == ARRAY_TYPE)
    {
      tree t_result = build4 (ARRAY_REF, t_type_star_ptr, t_ptr, t_index,
                              NULL_TREE, NULL_TREE);
      if (loc)
        set_tree_location (t_result, loc);
      return new lvalue (this, t_result);
    }
  else
    {
      /* Convert index to an offset in bytes.  */
      tree t_sizeof = size_in_bytes (t_type_star_ptr);
      t_index = fold_build1 (CONVERT_EXPR, sizetype, t_index);
      tree t_offset = build2 (MULT_EXPR, sizetype, t_index, t_sizeof);

      /* Locate (ptr + offset).  */
      tree t_address = build2 (POINTER_PLUS_EXPR, t_type_ptr, t_ptr, t_offset);

      tree t_indirection = build1 (INDIRECT_REF, t_type_star_ptr, t_address);
      if (loc)
        {
          set_tree_location (t_sizeof, loc);
          set_tree_location (t_offset, loc);
          set_tree_location (t_address, loc);
          set_tree_location (t_indirection, loc);
        }

      return new lvalue (this, t_indirection);
    }
}

/* Construct a tree for a field access.  */

tree
playback::context::
new_field_access (location *loc,
                  tree datum,
                  field *field)
{
  gcc_assert (datum);
  gcc_assert (field);

  /* Compare with c/c-typeck.c:lookup_field, build_indirect_ref, and
     build_component_ref. */
  tree type = TREE_TYPE (datum);
  gcc_assert (type);
  gcc_assert (TREE_CODE (type) != POINTER_TYPE);

 tree t_field = field->as_tree ();
 tree ref = build3 (COMPONENT_REF, TREE_TYPE (t_field), datum,
                     t_field, NULL_TREE);
  if (loc)
    set_tree_location (ref, loc);
  return ref;
}

/* Construct a tree for a dereference.  */

tree
playback::context::
new_dereference (tree ptr,
                 location *loc)
{
  gcc_assert (ptr);

  tree type = TREE_TYPE (TREE_TYPE(ptr));
  tree datum = build1 (INDIRECT_REF, type, ptr);
  if (loc)
    set_tree_location (datum, loc);
  return datum;
}

/* Construct a playback::lvalue instance (wrapping a tree) for a
   field access.  */

playback::lvalue *
playback::lvalue::
access_field (location *loc,
              field *field)
{
  tree datum = as_tree ();
  tree ref = get_context ()->new_field_access (loc, datum, field);
  if (!ref)
    return NULL;
  return new lvalue (get_context (), ref);
}

/* Construct a playback::rvalue instance (wrapping a tree) for a
   field access.  */

playback::rvalue *
playback::rvalue::
access_field (location *loc,
              field *field)
{
  tree datum = as_tree ();
  tree ref = get_context ()->new_field_access (loc, datum, field);
  if (!ref)
    return NULL;
  return new rvalue (get_context (), ref);
}

/* Construct a playback::lvalue instance (wrapping a tree) for a
   dereferenced field access.  */

playback::lvalue *
playback::rvalue::
dereference_field (location *loc,
                   field *field)
{
  tree ptr = as_tree ();
  tree datum = get_context ()->new_dereference (ptr, loc);
  if (!datum)
    return NULL;
  tree ref = get_context ()->new_field_access (loc, datum, field);
  if (!ref)
    return NULL;
  return new lvalue (get_context (), ref);
}

/* Construct a playback::lvalue instance (wrapping a tree) for a
   dereference.  */

playback::lvalue *
playback::rvalue::
dereference (location *loc)
{
  tree ptr = as_tree ();
  tree datum = get_context ()->new_dereference (ptr, loc);
  return new lvalue (get_context (), datum);
}

/* Construct a playback::rvalue instance (wrapping a tree) for an
   address-lookup.  */

playback::rvalue *
playback::lvalue::
get_address (location *loc)
{
  tree t_lvalue = as_tree ();
  tree t_thistype = TREE_TYPE (t_lvalue);
  tree t_ptrtype = build_pointer_type (t_thistype);
  tree ptr = build1 (ADDR_EXPR, t_ptrtype, t_lvalue);
  if (loc)
    get_context ()->set_tree_location (ptr, loc);
  return new rvalue (get_context (), ptr);
}

/* The wrapper subclasses are GC-managed, but can own non-GC memory.
   Provide this finalization hook for calling then they are collected,
   which calls the finalizer vfunc.  This allows them to call "release"
   on any vec<> within them.  */

static void
wrapper_finalizer (void *ptr)
{
  playback::wrapper *wrapper = reinterpret_cast <playback::wrapper *> (ptr);
  wrapper->finalizer ();
}

/* gcc::jit::playback::wrapper subclasses are GC-managed:
   allocate them using ggc_internal_cleared_alloc.  */

void *
playback::wrapper::
operator new (size_t sz)
{
  return ggc_internal_cleared_alloc (sz, wrapper_finalizer, 0, 1);

}

/* Constructor for gcc:jit::playback::function.  */

playback::function::
function (context *ctxt,
          tree fndecl,
          enum gcc_jit_function_kind kind)
: m_ctxt(ctxt),
  m_inner_fndecl (fndecl),
  m_inner_bind_expr (NULL),
  m_kind (kind)
{
  if (m_kind != GCC_JIT_FUNCTION_IMPORTED)
    {
      /* Create a BIND_EXPR, and within it, a statement list.  */
      m_stmt_list = alloc_stmt_list ();
      m_stmt_iter = tsi_start (m_stmt_list);
      m_inner_block = make_node (BLOCK);
      m_inner_bind_expr =
        build3 (BIND_EXPR, void_type_node, NULL, m_stmt_list, m_inner_block);
    }
  else
    {
      m_inner_block = NULL;
      m_stmt_list = NULL;
    }
}

/* Hand-written GC-marking hook for playback functions.  */

void
playback::function::
gt_ggc_mx ()
{
  gt_ggc_m_9tree_node (m_inner_fndecl);
  gt_ggc_m_9tree_node (m_inner_bind_expr);
  gt_ggc_m_9tree_node (m_stmt_list);
  gt_ggc_m_9tree_node (m_inner_block);
}

/* Don't leak vec's internal buffer (in non-GC heap) when we are
   GC-ed.  */

void
playback::function::finalizer ()
{
  m_blocks.release ();
}

/* Get the return type of a playback function, in tree form.  */

tree
playback::function::
get_return_type_as_tree () const
{
  return TREE_TYPE (TREE_TYPE(m_inner_fndecl));
}

/* Construct a new local within this playback::function.  */

playback::lvalue *
playback::function::
new_local (location *loc,
           type *type,
           const char *name)
{
  gcc_assert (type);
  gcc_assert (name);
  tree inner = build_decl (UNKNOWN_LOCATION, VAR_DECL,
                           get_identifier (name),
                           type->as_tree ());
  DECL_CONTEXT (inner) = this->m_inner_fndecl;

  /* Prepend to BIND_EXPR_VARS: */
  DECL_CHAIN (inner) = BIND_EXPR_VARS (m_inner_bind_expr);
  BIND_EXPR_VARS (m_inner_bind_expr) = inner;

  if (loc)
    set_tree_location (inner, loc);
  return new lvalue (m_ctxt, inner);
}

/* Construct a new block within this playback::function.  */

playback::block *
playback::function::
new_block (const char *name)
{
  gcc_assert (m_kind != GCC_JIT_FUNCTION_IMPORTED);

  block *result = new playback::block (this, name);
  m_blocks.safe_push (result);
  return result;
}

/* Build a statement list for the function as a whole out of the
   lists of statements for the individual blocks, building labels
   for each block.  */

void
playback::function::
build_stmt_list ()
{
  int i;
  block *b;

  FOR_EACH_VEC_ELT (m_blocks, i, b)
    {
      int j;
      tree stmt;

      b->m_label_expr = build1 (LABEL_EXPR,
                                void_type_node,
                                b->as_label_decl ());
      tsi_link_after (&m_stmt_iter, b->m_label_expr, TSI_CONTINUE_LINKING);

      FOR_EACH_VEC_ELT (b->m_stmts, j, stmt)
        tsi_link_after (&m_stmt_iter, stmt, TSI_CONTINUE_LINKING);
    }
}

/* Finish compiling the given function, potentially running the
   garbage-collector.
   The function will have a statement list by now.
   Amongst other things, this gimplifies the statement list,
   and calls cgraph_node::finalize_function on the function.  */

void
playback::function::
postprocess ()
{
  if (m_ctxt->get_bool_option (GCC_JIT_BOOL_OPTION_DUMP_INITIAL_TREE))
    debug_tree (m_stmt_list);

  /* Do we need this to force cgraphunit.c to output the function? */
  if (m_kind == GCC_JIT_FUNCTION_EXPORTED)
    {
      DECL_EXTERNAL (m_inner_fndecl) = 0;
      DECL_PRESERVE_P (m_inner_fndecl) = 1;
    }

  if (m_kind == GCC_JIT_FUNCTION_INTERNAL
      ||m_kind == GCC_JIT_FUNCTION_ALWAYS_INLINE)
    {
      DECL_EXTERNAL (m_inner_fndecl) = 0;
      TREE_PUBLIC (m_inner_fndecl) = 0;
    }

  if (m_kind != GCC_JIT_FUNCTION_IMPORTED)
    {
      /* Seem to need this in gimple-low.c: */
      gcc_assert (m_inner_block);
      DECL_INITIAL (m_inner_fndecl) = m_inner_block;

      /* how to add to function? the following appears to be how to
         set the body of a m_inner_fndecl: */
      DECL_SAVED_TREE(m_inner_fndecl) = m_inner_bind_expr;

      /* Ensure that locals appear in the debuginfo.  */
      BLOCK_VARS (m_inner_block) = BIND_EXPR_VARS (m_inner_bind_expr);

      //debug_tree (m_inner_fndecl);

      /* Convert to gimple: */
      //printf("about to gimplify_function_tree\n");
      gimplify_function_tree (m_inner_fndecl);
      //printf("finished gimplify_function_tree\n");

      current_function_decl = m_inner_fndecl;
      if (m_ctxt->get_bool_option (GCC_JIT_BOOL_OPTION_DUMP_INITIAL_GIMPLE))
        dump_function_to_file (m_inner_fndecl, stderr, TDF_VOPS|TDF_MEMSYMS|TDF_LINENO);
      //debug_tree (m_inner_fndecl);

      //printf("about to add to cgraph\n");
      /* Add to cgraph: */
      cgraph_node::finalize_function (m_inner_fndecl, false);
      /* This can trigger a collection, so we need to have all of
         the funcs as roots.  */

      current_function_decl = NULL;
    }
}

/* Don't leak vec's internal buffer (in non-GC heap) when we are
   GC-ed.  */

void
playback::block::finalizer ()
{
  m_stmts.release ();
}

/* Add an eval of the rvalue to the function's statement list.  */

void
playback::block::
add_eval (location *loc,
          rvalue *rvalue)
{
  gcc_assert (rvalue);

  if (loc)
    set_tree_location (rvalue->as_tree (), loc);

  add_stmt (rvalue->as_tree ());
}

/* Add an assignment to the function's statement list.  */

void
playback::block::
add_assignment (location *loc,
                lvalue *lvalue,
                rvalue *rvalue)
{
  gcc_assert (lvalue);
  gcc_assert (rvalue);

  tree t_lvalue = lvalue->as_tree ();
  tree t_rvalue = rvalue->as_tree ();
  if (TREE_TYPE (t_rvalue) != TREE_TYPE (t_lvalue))
    {
      t_rvalue = build1 (CONVERT_EXPR,
                         TREE_TYPE (t_lvalue),
                         t_rvalue);
      if (loc)
        set_tree_location (t_rvalue, loc);
    }

  tree stmt =
    build2 (MODIFY_EXPR, TREE_TYPE (t_lvalue),
            t_lvalue, t_rvalue);
  if (loc)
    set_tree_location (stmt, loc);
  add_stmt (stmt);
}

/* Add a comment to the function's statement list.
   For now this is done by adding a dummy label.  */

void
playback::block::
add_comment (location *loc,
             const char *text)
{
  /* Wrap the text in C-style comment delimiters.  */
  size_t sz =
    (3 /* opening delim */
     + strlen (text)
     + 3 /* closing delim */
     + 1 /* terminator */);
  char *wrapped = (char *)ggc_internal_alloc (sz);
  snprintf (wrapped, sz, "/* %s */", text);

  /* For now we simply implement this by adding a dummy label with a name
     containing the given text.  */
  tree identifier = get_identifier (wrapped);
  tree label_decl = build_decl (UNKNOWN_LOCATION, LABEL_DECL,
                                identifier, void_type_node);
  DECL_CONTEXT (label_decl) = m_func->as_fndecl ();

  tree label_expr = build1 (LABEL_EXPR, void_type_node, label_decl);
  if (loc)
    set_tree_location (label_expr, loc);
  add_stmt (label_expr);
}

/* Add a conditional jump statement to the function's statement list.  */

void
playback::block::
add_conditional (location *loc,
                 rvalue *boolval,
                 block *on_true,
                 block *on_false)
{
  gcc_assert (boolval);
  gcc_assert (on_true);
  gcc_assert (on_false);

  /* COND_EXPR wants statement lists for the true/false operands, but we
     want labels.
     Shim it by creating jumps to the labels */
  tree true_jump = build1 (GOTO_EXPR, void_type_node,
                           on_true->as_label_decl ());
  if (loc)
    set_tree_location (true_jump, loc);

  tree false_jump = build1 (GOTO_EXPR, void_type_node,
                            on_false->as_label_decl ());
  if (loc)
    set_tree_location (false_jump, loc);

  tree stmt =
    build3 (COND_EXPR, void_type_node, boolval->as_tree (),
            true_jump, false_jump);
  if (loc)
    set_tree_location (stmt, loc);
  add_stmt (stmt);
}

/* Add an unconditional jump statement to the function's statement list.  */

void
playback::block::
add_jump (location *loc,
          block *target)
{
  gcc_assert (target);

  // see c_finish_loop
  //tree top = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
  //add_stmt (top);

  //tree stmt = build_and_jump (&LABEL_EXPR_LABEL (target->label_));
  TREE_USED (target->as_label_decl ()) = 1;
  tree stmt = build1 (GOTO_EXPR, void_type_node, target->as_label_decl ());
  if (loc)
    set_tree_location (stmt, loc);
  add_stmt (stmt);

  /*
  from c-typeck.c:
tree
c_finish_goto_label (location_t loc, tree label)
{
  tree decl = lookup_label_for_goto (loc, label);
  if (!decl)
    return NULL_TREE;
  TREE_USED (decl) = 1;
  {
    tree t = build1 (GOTO_EXPR, void_type_node, decl);
    SET_EXPR_LOCATION (t, loc);
    return add_stmt (t);
  }
}
  */

}

/* Add a return statement to the function's statement list.  */

void
playback::block::
add_return (location *loc,
            rvalue *rvalue)
{
  tree modify_retval = NULL;
  tree return_type = m_func->get_return_type_as_tree ();
  if (rvalue)
    {
      tree t_lvalue = DECL_RESULT (m_func->as_fndecl ());
      tree t_rvalue = rvalue->as_tree ();
      if (TREE_TYPE (t_rvalue) != TREE_TYPE (t_lvalue))
        t_rvalue = build1 (CONVERT_EXPR,
                           TREE_TYPE (t_lvalue),
                           t_rvalue);
      modify_retval = build2 (MODIFY_EXPR, return_type,
                              t_lvalue, t_rvalue);
      if (loc)
        set_tree_location (modify_retval, loc);
    }
  tree return_stmt = build1 (RETURN_EXPR, return_type,
                             modify_retval);
  if (loc)
    set_tree_location (return_stmt, loc);

  add_stmt (return_stmt);
}

/* Constructor for gcc::jit::playback::block.  */

playback::block::
block (function *func,
       const char *name)
: m_func (func),
  m_stmts ()
{
  tree identifier;

  gcc_assert (func);
  // name can be NULL
  if (name)
    identifier = get_identifier (name);
  else
    identifier = NULL;
  m_label_decl = build_decl (UNKNOWN_LOCATION, LABEL_DECL,
                            identifier, void_type_node);
  DECL_CONTEXT (m_label_decl) = func->as_fndecl ();
  m_label_expr = NULL;
}

/* Construct a tempdir path template suitable for use by mkdtemp
   e.g. "/tmp/libgccjit-XXXXXX", but respecting the rules in
   libiberty's choose_tempdir rather than hardcoding "/tmp/".

   The memory is allocated using malloc and must be freed.
   Aborts the process if allocation fails. */

static char *
make_tempdir_path_template ()
{
  const char *tmpdir_buf;
  size_t tmpdir_len;
  const char *file_template_buf;
  size_t file_template_len;
  char *result;

  /* The result of choose_tmpdir is a cached buffer within libiberty, so
     we must *not* free it.  */
  tmpdir_buf = choose_tmpdir ();

  /* choose_tmpdir aborts on malloc failure.  */
  gcc_assert (tmpdir_buf);

  tmpdir_len = strlen (tmpdir_buf);
  /* tmpdir_buf should now have a dir separator as the final byte.  */
  gcc_assert (tmpdir_len > 0);
  gcc_assert (tmpdir_buf[tmpdir_len - 1] == DIR_SEPARATOR);

  file_template_buf = "libgccjit-XXXXXX";
  file_template_len = strlen (file_template_buf);

  result = XNEWVEC (char, tmpdir_len + file_template_len + 1);
  strcpy (result, tmpdir_buf);
  strcpy (result + tmpdir_len, file_template_buf);

  return result;
}

/* Compile a playback::context:

   - Use the context's options to cconstruct command-line options, and
     call into the rest of GCC (toplev::main).
   - Assuming it succeeds, we have a .s file; we want a .so file.
     Invoke another gcc to convert the .s file to a .so file.
   - dlopen the .so file
   - Wrap the result up as a playback::result and return it.  */

result *
playback::context::
compile ()
{
  void *handle = NULL;
  const char *ctxt_progname;
  result *result_obj = NULL;

  m_path_template = make_tempdir_path_template ();
  if (!m_path_template)
    return NULL;

  /* Create tempdir using mkdtemp.  This is created with 0700 perms and
     is unique.  Hence no other (non-root) users should have access to
     the paths within it.  */
  m_path_tempdir = mkdtemp (m_path_template);
  if (!m_path_tempdir)
    return NULL;
  m_path_c_file = concat (m_path_tempdir, "/fake.c", NULL);
  m_path_s_file = concat (m_path_tempdir, "/fake.s", NULL);
  m_path_so_file = concat (m_path_tempdir, "/fake.so", NULL);

  /* Call into the rest of gcc.
     For now, we have to assemble command-line options to pass into
     toplev::main, so that they can be parsed. */

  /* Pass in user-provided program name as argv0, if any, so that it
     makes it into GCC's "progname" global, used in various diagnostics. */
  ctxt_progname = get_str_option (GCC_JIT_STR_OPTION_PROGNAME);

  if (!ctxt_progname)
    ctxt_progname = "libgccjit.so";

  auto_vec <const char *> fake_args;
  make_fake_args (&fake_args, ctxt_progname);
  if (errors_occurred ())
    return NULL;

  toplev toplev (false);
  toplev.main (fake_args.length (),
               const_cast <char **> (fake_args.address ()));
  toplev.finalize ();

  active_playback_ctxt = NULL;

  if (errors_occurred ())
    return NULL;

  if (get_bool_option (GCC_JIT_BOOL_OPTION_DUMP_GENERATED_CODE))
    dump_generated_code ();

  convert_to_dso (ctxt_progname);
  if (errors_occurred ())
    return NULL;

  /* dlopen the .so file. */
  {
    auto_timevar load_timevar (TV_LOAD);

    const char *error;

    /* Clear any existing error.  */
    dlerror ();

    handle = dlopen (m_path_so_file, RTLD_NOW | RTLD_LOCAL);
    if ((error = dlerror()) != NULL)  {
      add_error (NULL, "%s", error);
    }
    if (handle)
      result_obj = new result (handle);
    else
      result_obj = NULL;
  }

  return result_obj;
}

/* Helper functions for gcc::jit::playback::context::compile.  */

/* Build a fake argv for toplev::main from the options set
   by the user on the context .  */

void
playback::context::
make_fake_args (auto_vec <const char *> *argvec,
                const char *ctxt_progname)
{
#define ADD_ARG(arg) argvec->safe_push (arg)

  ADD_ARG (ctxt_progname);
  ADD_ARG (m_path_c_file);
  ADD_ARG ("-fPIC");

  /* Handle int options: */
  switch (get_int_option (GCC_JIT_INT_OPTION_OPTIMIZATION_LEVEL))
    {
    default:
      add_error (NULL,
                 "unrecognized optimization level: %i",
                 get_int_option (GCC_JIT_INT_OPTION_OPTIMIZATION_LEVEL));
      return;

    case 0:
      ADD_ARG ("-O0");
      break;

    case 1:
      ADD_ARG ("-O1");
      break;

    case 2:
      ADD_ARG ("-O2");
      break;

    case 3:
      ADD_ARG ("-O3");
      break;
    }
  /* What about -Os? */

  /* Handle bool options: */
  if (get_bool_option (GCC_JIT_BOOL_OPTION_DEBUGINFO))
    ADD_ARG ("-g");

  /* Suppress timing (and other) info.  */
  if (!get_bool_option (GCC_JIT_BOOL_OPTION_DUMP_SUMMARY))
    {
      ADD_ARG ("-quiet");
      quiet_flag = 1;
    }

  /* Aggressively garbage-collect, to shake out bugs: */
  if (get_bool_option (GCC_JIT_BOOL_OPTION_SELFCHECK_GC))
    {
      ADD_ARG ("--param");
      ADD_ARG ("ggc-min-expand=0");
      ADD_ARG ("--param");
      ADD_ARG ("ggc-min-heapsize=0");
    }

  if (get_bool_option (GCC_JIT_BOOL_OPTION_DUMP_EVERYTHING))
    {
      ADD_ARG ("-fdump-tree-all");
      ADD_ARG ("-fdump-rtl-all");
      ADD_ARG ("-fdump-ipa-all");
    }
#undef ADD_ARG
}

/* Part of playback::context::compile ().

   We have a .s file; we want a .so file.
   We could reuse parts of gcc/gcc.c to do this.
   For now, just use the driver binary from the install, as
   named in gcc-driver-name.h
   e.g. "x86_64-unknown-linux-gnu-gcc-5.0.0".  */

void
playback::context::
convert_to_dso (const char *ctxt_progname)
{
  /* Currently this lumps together both assembling and linking into
     TV_ASSEMBLE.  */
  auto_timevar assemble_timevar (TV_ASSEMBLE);
  const char *errmsg;
  const char *argv[7];
  int exit_status = 0;
  int err = 0;
  const char *gcc_driver_name = GCC_DRIVER_NAME;

  argv[0] = gcc_driver_name;
  argv[1] = "-shared";
  /* The input: assembler.  */
  argv[2] = m_path_s_file;
  /* The output: shared library.  */
  argv[3] = "-o";
  argv[4] = m_path_so_file;

  /* Don't use the linker plugin.
     If running with just a "make" and not a "make install", then we'd
     run into
       "fatal error: -fuse-linker-plugin, but liblto_plugin.so not found"
     libto_plugin is a .la at build time, with it becoming installed with
     ".so" suffix: i.e. it doesn't exist with a .so suffix until install
     time.  */
  argv[5] = "-fno-use-linker-plugin";

  /* pex argv arrays are NULL-terminated.  */
  argv[6] = NULL;

  /* pex_one's error-handling requires pname to be non-NULL.  */
  gcc_assert (ctxt_progname);

  errmsg = pex_one (PEX_SEARCH, /* int flags, */
                    gcc_driver_name,
                    const_cast<char * const *> (argv),
                    ctxt_progname, /* const char *pname */
                    NULL, /* const char *outname */
                    NULL, /* const char *errname */
                    &exit_status, /* int *status */
                    &err); /* int *err*/
  if (errmsg)
    {
      add_error (NULL, "error invoking gcc driver: %s", errmsg);
      return;
    }

  /* pex_one can return a NULL errmsg when the executable wasn't
     found (or doesn't exist), so trap these cases also.  */
  if (exit_status || err)
    {
      add_error (NULL,
                 "error invoking gcc driver: exit_status: %i err: %i",
                 exit_status, err);
      add_error (NULL,
                 "whilst attempting to run a driver named: %s",
                 gcc_driver_name);
      add_error (NULL,
                 "PATH was: %s",
                 getenv ("PATH"));
      return;
    }
}

/* Top-level hook for playing back a recording context.

   This plays back m_recording_ctxt, and, if no errors
   occurred builds statement lists for and then postprocesses
   every function in the result.  */

void
playback::context::
replay ()
{
  /* Adapted from c-common.c:c_common_nodes_and_builtins.  */
  tree array_domain_type = build_index_type (size_int (200));
  m_char_array_type_node
    = build_array_type (char_type_node, array_domain_type);

  m_const_char_ptr
    = build_pointer_type (build_qualified_type (char_type_node,
                                                TYPE_QUAL_CONST));

  /* Replay the recorded events:  */
  timevar_push (TV_JIT_REPLAY);

  m_recording_ctxt->replay_into (this);

  /* Clean away the temporary references from recording objects
     to playback objects.  We have to do this now since the
     latter are GC-allocated, but the former don't mark these
     refs.  Hence we must stop using them before the GC can run.  */
  m_recording_ctxt->disassociate_from_playback ();

  /* The builtins_manager, if any, is associated with the recording::context
     and might be reused for future compiles on other playback::contexts,
     but its m_attributes array is not GTY-labeled and hence will become
     nonsense if the GC runs.  Purge this state.  */
  builtins_manager *bm = get_builtins_manager ();
  if (bm)
    bm->finish_playback ();

  timevar_pop (TV_JIT_REPLAY);

  if (!errors_occurred ())
    {
      int i;
      function *func;

      /* No GC can happen yet; process the cached source locations.  */
      handle_locations ();

      /* We've now created tree nodes for the stmts in the various blocks
         in each function, but we haven't built each function's single stmt
         list yet.  Do so now.  */
      FOR_EACH_VEC_ELT (m_functions, i, func)
        func->build_stmt_list ();

      /* No GC can have happened yet.  */

      /* Postprocess the functions.  This could trigger GC.  */
      FOR_EACH_VEC_ELT (m_functions, i, func)
        {
          gcc_assert (func);
          func->postprocess ();
        }
    }
}

/* Dump the generated .s file to stderr.  */

void
playback::context::
dump_generated_code ()
{
  char buf[4096];
  size_t sz;
  FILE *f_in = fopen (m_path_s_file, "r");
  if (!f_in)
    return;

  while ( (sz = fread (buf, 1, sizeof (buf), f_in)) )
    fwrite (buf, 1, sz, stderr);

  fclose (f_in);
}

/* qsort comparator for comparing pairs of playback::source_line *,
   ordering them by line number.  */

static int
line_comparator (const void *lhs, const void *rhs)
{
  const playback::source_line *line_lhs = \
    *static_cast<const playback::source_line * const*> (lhs);
  const playback::source_line *line_rhs = \
    *static_cast<const playback::source_line * const*> (rhs);
  return line_lhs->get_line_num () - line_rhs->get_line_num ();
}

/* qsort comparator for comparing pairs of playback::location *,
   ordering them by column number.  */

static int
location_comparator (const void *lhs, const void *rhs)
{
  const playback::location *loc_lhs = \
    *static_cast<const playback::location * const *> (lhs);
  const playback::location *loc_rhs = \
    *static_cast<const playback::location * const *> (rhs);
  return loc_lhs->get_column_num () - loc_rhs->get_column_num ();
}

/* Our API allows locations to be created in arbitrary orders, but the
   linemap API requires locations to be created in ascending order
   as if we were tokenizing files.

   This hook sorts all of the the locations that have been created, and
   calls into the linemap API, creating linemap entries in sorted order
   for our locations.  */

void
playback::context::
handle_locations ()
{
  /* Create the source code locations, following the ordering rules
     imposed by the linemap API.

     line_table is a global.  */
  int i;
  source_file *file;

  FOR_EACH_VEC_ELT (m_source_files, i, file)
    {
      linemap_add (line_table, LC_ENTER, false, file->get_filename (), 0);

      /* Sort lines by ascending line numbers.  */
      file->m_source_lines.qsort (&line_comparator);

      int j;
      source_line *line;
      FOR_EACH_VEC_ELT (file->m_source_lines, j, line)
        {
          int k;
          location *loc;

          /* Sort locations in line by ascending column numbers.  */
          line->m_locations.qsort (&location_comparator);

          /* Determine maximum column within this line.  */
          gcc_assert (line->m_locations.length () > 0);
          location *final_column =
            line->m_locations[line->m_locations.length () - 1];
          int max_col = final_column->get_column_num ();

          linemap_line_start (line_table, line->get_line_num (), max_col);
          FOR_EACH_VEC_ELT (line->m_locations, k, loc)
            {
              loc->m_srcloc =                                      \
                linemap_position_for_column (line_table, loc->get_column_num ());
            }
        }

      linemap_add (line_table, LC_LEAVE, false, NULL, 0);
    }

  /* line_table should now be populated; every playback::location should
     now have an m_srcloc.  */

  /* Now assign them to tree nodes as appropriate.  */
  std::pair<tree, location *> *cached_location;

  FOR_EACH_VEC_ELT (m_cached_locations, i, cached_location)
    {
      tree t = cached_location->first;
      source_location srcloc = cached_location->second->m_srcloc;

      /* This covers expressions: */
      if (CAN_HAVE_LOCATION_P (t))
        SET_EXPR_LOCATION (t, srcloc);
      else if (CODE_CONTAINS_STRUCT(TREE_CODE(t), TS_DECL_MINIMAL))
        DECL_SOURCE_LOCATION (t) = srcloc;
      else
        {
          /* Don't know how to set location on this node.  */
        }
    }
}

/* We handle errors on a playback::context by adding them to the
   corresponding recording::context.  */

void
playback::context::
add_error (location *loc, const char *fmt, ...)
{
  va_list ap;
  va_start (ap, fmt);
  m_recording_ctxt->add_error_va (loc ? loc->get_recording_loc () : NULL,
                                  fmt, ap);
  va_end (ap);
}

/* We handle errors on a playback::context by adding them to the
   corresponding recording::context.  */

void
playback::context::
add_error_va (location *loc, const char *fmt, va_list ap)
{
  m_recording_ctxt->add_error_va (loc ? loc->get_recording_loc () : NULL,
                                  fmt, ap);
}

/* Dealing with the linemap API.  */

/* Construct a playback::location for a recording::location, if it
   doesn't exist already.  */

playback::location *
playback::context::
new_location (recording::location *rloc,
              const char *filename,
              int line,
              int column)
{
  /* Get the source_file for filename, creating if necessary.  */
  source_file *src_file = get_source_file (filename);
  /* Likewise for the line within the file.  */
  source_line *src_line = src_file->get_source_line (line);
  /* Likewise for the column within the line.  */
  location *loc = src_line->get_location (rloc, column);
  return loc;
}

/* Deferred setting of the location for a given tree, by adding the
   (tree, playback::location) pair to a list of deferred associations.
   We will actually set the location on the tree later on once
   the source_location for the playback::location exists.  */

void
playback::context::
set_tree_location (tree t, location *loc)
{
  gcc_assert (loc);
  m_cached_locations.safe_push (std::make_pair (t, loc));
}


/* Construct a playback::source_file for the given source
   filename, if it doesn't exist already.  */

playback::source_file *
playback::context::
get_source_file (const char *filename)
{
  /* Locate the file.
     For simplicitly, this is currently a linear search.
     Replace with a hash if this shows up in the profile.  */
  int i;
  source_file *file;
  tree ident_filename = get_identifier (filename);

  FOR_EACH_VEC_ELT (m_source_files, i, file)
    if (file->filename_as_tree () == ident_filename)
      return file;

  /* Not found.  */
  file = new source_file (ident_filename);
  m_source_files.safe_push (file);
  return file;
}

/* Constructor for gcc::jit::playback::source_file.  */

playback::source_file::source_file (tree filename) :
  m_source_lines (),
  m_filename (filename)
{
}

/* Don't leak vec's internal buffer (in non-GC heap) when we are
   GC-ed.  */

void
playback::source_file::finalizer ()
{
  m_source_lines.release ();
}

/* Construct a playback::source_line for the given line
   within this source file, if one doesn't exist already.  */

playback::source_line *
playback::source_file::
get_source_line (int line_num)
{
  /* Locate the line.
     For simplicitly, this is currently a linear search.
     Replace with a hash if this shows up in the profile.  */
  int i;
  source_line *line;

  FOR_EACH_VEC_ELT (m_source_lines, i, line)
    if (line->get_line_num () == line_num)
      return line;

  /* Not found.  */
  line = new source_line (this, line_num);
  m_source_lines.safe_push (line);
  return line;
}

/* Constructor for gcc::jit::playback::source_line.  */

playback::source_line::source_line (source_file *file, int line_num) :
  m_locations (),
  m_source_file (file),
  m_line_num (line_num)
{
}

/* Don't leak vec's internal buffer (in non-GC heap) when we are
   GC-ed.  */

void
playback::source_line::finalizer ()
{
  m_locations.release ();
}

/* Construct a playback::location for the given column
   within this line of a specific source file, if one doesn't exist
   already.  */

playback::location *
playback::source_line::
get_location (recording::location *rloc, int column_num)
{
  int i;
  location *loc;

  /* Another linear search that probably should be a hash table.  */
  FOR_EACH_VEC_ELT (m_locations, i, loc)
    if (loc->get_column_num () == column_num)
      return loc;

  /* Not found.  */
  loc = new location (rloc, this, column_num);
  m_locations.safe_push (loc);
  return loc;
}

/* Constructor for gcc::jit::playback::location.  */

playback::location::location (recording::location *loc,
                              source_line *line,
                              int column_num) :
  m_srcloc (UNKNOWN_LOCATION),
  m_recording_loc (loc),
  m_line (line),
  m_column_num(column_num)
{
}

/* The active gcc::jit::playback::context instance.  This is a singleton,
   guarded by jit_mutex.  */

playback::context *active_playback_ctxt;

} // namespace gcc::jit

} // namespace gcc