libcc1/gdbctx.hh

   1 /* Generic GDB-side plugin
   2    Copyright (C) 2020-2022 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 under
   7 the terms of the GNU General Public License as published by the Free
   8 Software Foundation; either version 3, or (at your option) any later
   9 version.
  10
  11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14 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 #ifndef CC1_PLUGIN_GDBCTX_HH
  21 #define CC1_PLUGIN_GDBCTX_HH
  22
  23 namespace cc1_plugin
  24 {
  25   // The compiler context that we hand back to our caller.
  26   // Due to this, the entire implementation is in this header.
  27   template<typename T>
  28   struct base_gdb_plugin : public T
  29   {
  30     base_gdb_plugin (const char *plugin_name_, const char *base_name,
  31                      int version)
  32       : verbose (false),
  33         plugin_name (plugin_name_),
  34         fe_version (version),
  35         compiler_name (base_name),
  36         compilerp (new compiler (verbose))
  37     {
  38       vtable =
  39         {
  40           GCC_FE_VERSION_1,
  41           do_set_arguments_v0,
  42           do_set_source_file,
  43           do_set_print_callback,
  44           do_compile_v0,
  45           do_destroy,
  46           do_set_verbose,
  47           do_compile,
  48           do_set_arguments,
  49           do_set_triplet_regexp,
  50           do_set_driver_filename,
  51         };
  52
  53       this->base.ops = &vtable;
  54     }
  55
  56     virtual ~base_gdb_plugin () = default;
  57
  58     // A convenience function to print something.
  59     void print (const char *str)
  60     {
  61       this->print_function (this->print_datum, str);
  62     }
  63
  64     // Set the verbose flag.
  65     void set_verbose (bool v)
  66     {
  67       verbose = v;
  68       if (compilerp != nullptr)
  69         compilerp->set_verbose (v);
  70     }
  71
  72     // Make a new connection.
  73     void set_connection (int fd, int aux_fd)
  74     {
  75       connection.reset (new local_connection (fd, aux_fd, this));
  76     }
  77
  78     // This is called just before compilation begins.  It should set
  79     // any needed callbacks on the connection.
  80     virtual void add_callbacks () = 0;
  81
  82     // A local subclass of connection that holds a back-pointer to the
  83     // context object that we provide to our caller.
  84     class local_connection : public cc1_plugin::connection
  85     {
  86     public:
  87
  88       local_connection (int fd, int aux_fd, base_gdb_plugin<T> *b)
  89         : connection (fd, aux_fd),
  90           back_ptr (b)
  91       {
  92       }
  93
  94       void print (const char *buf) override
  95       {
  96         back_ptr->print (buf);
  97       }
  98
  99       base_gdb_plugin<T> *back_ptr;
 100     };
 101
 102     std::unique_ptr<local_connection> connection;
 103
 104     void (*print_function) (void *datum, const char *message) = nullptr;
 105     void *print_datum = nullptr;
 106
 107     std::vector<std::string> args;
 108     std::string source_file;
 109
 110     /* Non-zero as an equivalent to gcc driver option "-v".  */
 111     bool verbose;
 112
 113     const char *plugin_name;
 114     int fe_version;
 115
 116     const char *compiler_name;
 117     std::unique_ptr<cc1_plugin::compiler> compilerp;
 118
 119   private:
 120
 121     struct gcc_base_vtable vtable;
 122
 123     static inline base_gdb_plugin<T> *
 124     get_self (gcc_base_context *s)
 125     {
 126       T *sub = (T *) s;
 127       return static_cast<base_gdb_plugin<T> *> (sub);
 128     }
 129
 130     static void
 131     do_set_verbose (struct gcc_base_context *s, int /* bool */ verbose)
 132     {
 133       base_gdb_plugin<T> *self = get_self (s);
 134
 135       self->set_verbose (verbose != 0);
 136     }
 137
 138     static char *
 139     do_set_arguments (struct gcc_base_context *s,
 140                       int argc, char **argv)
 141     {
 142       base_gdb_plugin<T> *self = get_self (s);
 143
 144       std::string compiler;
 145       char *errmsg = self->compilerp->find (self->compiler_name, compiler);
 146       if (errmsg != NULL)
 147         return errmsg;
 148
 149       self->args.push_back (compiler);
 150
 151       for (int i = 0; i < argc; ++i)
 152         self->args.push_back (argv[i]);
 153
 154       return NULL;
 155     }
 156
 157     static char *
 158     do_set_triplet_regexp (struct gcc_base_context *s,
 159                            const char *triplet_regexp)
 160     {
 161       base_gdb_plugin<T> *self = get_self (s);
 162
 163       self->compilerp.reset
 164         (new cc1_plugin::compiler_triplet_regexp (self->verbose,
 165                                                   triplet_regexp));
 166       return NULL;
 167     }
 168
 169     static char *
 170     do_set_driver_filename (struct gcc_base_context *s,
 171                             const char *driver_filename)
 172     {
 173       base_gdb_plugin<T> *self = get_self (s);
 174
 175       self->compilerp.reset
 176         (new cc1_plugin::compiler_driver_filename (self->verbose,
 177                                                    driver_filename));
 178       return NULL;
 179     }
 180
 181     static char *
 182     do_set_arguments_v0 (struct gcc_base_context *s,
 183                          const char *triplet_regexp,
 184                          int argc, char **argv)
 185     {
 186       char *errmsg = do_set_triplet_regexp (s, triplet_regexp);
 187       if (errmsg != NULL)
 188         return errmsg;
 189
 190       return do_set_arguments (s, argc, argv);
 191     }
 192
 193     static void
 194     do_set_source_file (struct gcc_base_context *s,
 195                         const char *file)
 196     {
 197       base_gdb_plugin<T> *self = get_self (s);
 198
 199       self->source_file = file;
 200     }
 201
 202     static void
 203     do_set_print_callback (struct gcc_base_context *s,
 204                            void (*print_function) (void *datum,
 205                                                    const char *message),
 206                            void *datum)
 207     {
 208       base_gdb_plugin<T> *self = get_self (s);
 209
 210       self->print_function = print_function;
 211       self->print_datum = datum;
 212     }
 213
 214     int fork_exec (char **argv, int spair_fds[2], int stderr_fds[2])
 215     {
 216       pid_t child_pid = fork ();
 217
 218       if (child_pid == -1)
 219         {
 220           close (spair_fds[0]);
 221           close (spair_fds[1]);
 222           close (stderr_fds[0]);
 223           close (stderr_fds[1]);
 224           return 0;
 225         }
 226
 227       if (child_pid == 0)
 228         {
 229           // Child.
 230           dup2 (stderr_fds[1], 1);
 231           dup2 (stderr_fds[1], 2);
 232           close (stderr_fds[0]);
 233           close (stderr_fds[1]);
 234           close (spair_fds[0]);
 235
 236           execvp (argv[0], argv);
 237           _exit (127);
 238         }
 239       else
 240         {
 241           // Parent.
 242           close (spair_fds[1]);
 243           close (stderr_fds[1]);
 244
 245           cc1_plugin::status result = cc1_plugin::FAIL;
 246           if (connection->send ('H')
 247               && ::cc1_plugin::marshall (connection.get (), fe_version))
 248             result = connection->wait_for_query ();
 249
 250           close (spair_fds[0]);
 251           close (stderr_fds[0]);
 252
 253           while (true)
 254             {
 255               int status;
 256
 257               if (waitpid (child_pid, &status, 0) == -1)
 258                 {
 259                   if (errno != EINTR)
 260                     return 0;
 261                 }
 262
 263               if (!WIFEXITED (status) || WEXITSTATUS (status) != 0)
 264                 return 0;
 265               break;
 266             }
 267
 268           if (!result)
 269             return 0;
 270           return 1;
 271         }
 272     }
 273
 274     static int
 275     do_compile (struct gcc_base_context *s,
 276                 const char *filename)
 277     {
 278       base_gdb_plugin<T> *self = get_self (s);
 279
 280       int fds[2];
 281       if (socketpair (AF_UNIX, SOCK_STREAM, 0, fds) != 0)
 282         {
 283           self->print ("could not create socketpair\n");
 284           return 0;
 285         }
 286
 287       int stderr_fds[2];
 288       if (pipe (stderr_fds) != 0)
 289         {
 290           self->print ("could not create pipe\n");
 291           close (fds[0]);
 292           close (fds[1]);
 293           return 0;
 294         }
 295
 296       self->args.push_back (std::string ("-fplugin=") + self->plugin_name);
 297       self->args.push_back (std::string ("-fplugin-arg-") + self->plugin_name
 298                             + "-fd=" + std::to_string (fds[1]));
 299
 300       self->args.push_back (self->source_file);
 301       self->args.push_back ("-c");
 302       self->args.push_back ("-o");
 303       self->args.push_back (filename);
 304       if (self->verbose)
 305         self->args.push_back ("-v");
 306
 307       self->set_connection (fds[0], stderr_fds[0]);
 308
 309       self->add_callbacks ();
 310
 311       std::vector<char *> argv (self->args.size () + 1);
 312       for (unsigned int i = 0; i < self->args.size (); ++i)
 313         argv[i] = const_cast<char *> (self->args[i].c_str ());
 314
 315       return self->fork_exec (argv.data (), fds, stderr_fds);
 316     }
 317
 318     static int
 319     do_compile_v0 (struct gcc_base_context *s, const char *filename,
 320                    int verbose)
 321     {
 322       do_set_verbose (s, verbose);
 323       return do_compile (s, filename);
 324     }
 325
 326     static void
 327     do_destroy (struct gcc_base_context *s)
 328     {
 329       base_gdb_plugin<T> *self = get_self (s);
 330
 331       delete self;
 332     }
 333   };
 334
 335   // Instances of this rpc<> template function are installed into the
 336   // "vtable"s.  These functions are parameterized by type and method
 337   // name and forward the call via the connection.
 338   template<typename CTX, typename R, const char *&NAME, typename... Arg>
 339   R rpc (CTX *s, Arg... rest)
 340   {
 341     base_gdb_plugin<CTX> *self = (base_gdb_plugin<CTX> *) s;
 342     R result;
 343
 344     if (!cc1_plugin::call (self->connection.get (), NAME, &result, rest...))
 345       return 0;
 346     return result;
 347   }
 348 }
 349
 350 #endif // CC1_PLUGIN_GDBCTX_HH