gcc/jit/docs/examples/tut01-hello-world.cc

   1 /* Smoketest example for libgccjit.so C++ API
   2    Copyright (C) 2014-2015 Free Software Foundation, Inc.
   3
   4 This file is part of GCC.
   5
   6 GCC is free software; you can redistribute it and/or modify it
   7 under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 3, or (at your option)
   9 any later version.
  10
  11 GCC is distributed in the hope that it will be useful, but
  12 WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GCC; see the file COPYING3.  If not see
  18 <http://www.gnu.org/licenses/>.  */
  19
  20 #include <libgccjit++.h>
  21
  22 #include <stdlib.h>
  23 #include <stdio.h>
  24
  25 static void
  26 create_code (gccjit::context ctxt)
  27 {
  28   /* Let's try to inject the equivalent of this C code:
  29      void
  30      greet (const char *name)
  31      {
  32         printf ("hello %s\n", name);
  33      }
  34   */
  35   gccjit::type void_type = ctxt.get_type (GCC_JIT_TYPE_VOID);
  36   gccjit::type const_char_ptr_type =
  37     ctxt.get_type (GCC_JIT_TYPE_CONST_CHAR_PTR);
  38   gccjit::param param_name =
  39     ctxt.new_param (const_char_ptr_type, "name");
  40   std::vector<gccjit::param> func_params;
  41   func_params.push_back (param_name);
  42   gccjit::function func =
  43     ctxt.new_function (GCC_JIT_FUNCTION_EXPORTED,
  44                        void_type,
  45                        "greet",
  46                        func_params, 0);
  47
  48   gccjit::param param_format =
  49     ctxt.new_param (const_char_ptr_type, "format");
  50   std::vector<gccjit::param> printf_params;
  51   printf_params.push_back (param_format);
  52   gccjit::function printf_func =
  53     ctxt.new_function (GCC_JIT_FUNCTION_IMPORTED,
  54                        ctxt.get_type (GCC_JIT_TYPE_INT),
  55                        "printf",
  56                        printf_params, 1);
  57
  58   gccjit::block block = func.new_block ();
  59   block.add_eval (ctxt.new_call (printf_func,
  60                                  ctxt.new_rvalue ("hello %s\n"),
  61                                  param_name));
  62   block.end_with_return ();
  63 }
  64
  65 int
  66 main (int argc, char **argv)
  67 {
  68   gccjit::context ctxt;
  69   gcc_jit_result *result;
  70
  71   /* Get a "context" object for working with the library.  */
  72   ctxt = gccjit::context::acquire ();
  73
  74   /* Set some options on the context.
  75      Turn this on to see the code being generated, in assembler form.  */
  76   ctxt.set_bool_option (GCC_JIT_BOOL_OPTION_DUMP_GENERATED_CODE, 0);
  77
  78   /* Populate the context.  */
  79   create_code (ctxt);
  80
  81   /* Compile the code.  */
  82   result = ctxt.compile ();
  83   if (!result)
  84     {
  85       fprintf (stderr, "NULL result");
  86       exit (1);
  87     }
  88
  89   ctxt.release ();
  90
  91   /* Extract the generated code from "result".  */
  92   typedef void (*fn_type) (const char *);
  93   fn_type greet =
  94     (fn_type)gcc_jit_result_get_code (result, "greet");
  95   if (!greet)
  96     {
  97       fprintf (stderr, "NULL greet");
  98       exit (1);
  99     }
 100
 101   /* Now call the generated function: */
 102   greet ("world");
 103   fflush (stdout);
 104
 105   gcc_jit_result_release (result);
 106   return 0;
 107 }