| 1 | /* C language support for compilation. |
| 2 | |
| 3 | Copyright (C) 2014-2018 Free Software Foundation, Inc. |
| 4 | |
| 5 | This file is part of GDB. |
| 6 | |
| 7 | This program is free software; you can redistribute it and/or modify |
| 8 | it under the terms of the GNU General Public License as published by |
| 9 | the Free Software Foundation; either version 3 of the License, or |
| 10 | (at your option) any later version. |
| 11 | |
| 12 | This program is distributed in the hope that it will be useful, |
| 13 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | GNU General Public License for more details. |
| 16 | |
| 17 | You should have received a copy of the GNU General Public License |
| 18 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 19 | |
| 20 | #include "defs.h" |
| 21 | #include "compile-internal.h" |
| 22 | #include "compile-c.h" |
| 23 | #include "compile.h" |
| 24 | #include "gdb-dlfcn.h" |
| 25 | #include "c-lang.h" |
| 26 | #include "macrotab.h" |
| 27 | #include "macroscope.h" |
| 28 | #include "regcache.h" |
| 29 | #include "common/function-view.h" |
| 30 | #include "common/preprocessor.h" |
| 31 | |
| 32 | /* See compile-internal.h. */ |
| 33 | |
| 34 | const char * |
| 35 | c_get_mode_for_size (int size) |
| 36 | { |
| 37 | const char *mode = NULL; |
| 38 | |
| 39 | switch (size) |
| 40 | { |
| 41 | case 1: |
| 42 | mode = "QI"; |
| 43 | break; |
| 44 | case 2: |
| 45 | mode = "HI"; |
| 46 | break; |
| 47 | case 4: |
| 48 | mode = "SI"; |
| 49 | break; |
| 50 | case 8: |
| 51 | mode = "DI"; |
| 52 | break; |
| 53 | default: |
| 54 | internal_error (__FILE__, __LINE__, _("Invalid GCC mode size %d."), size); |
| 55 | } |
| 56 | |
| 57 | return mode; |
| 58 | } |
| 59 | |
| 60 | /* See compile-internal.h. */ |
| 61 | |
| 62 | std::string |
| 63 | c_get_range_decl_name (const struct dynamic_prop *prop) |
| 64 | { |
| 65 | return string_printf ("__gdb_prop_%s", host_address_to_string (prop)); |
| 66 | } |
| 67 | |
| 68 | \f |
| 69 | |
| 70 | /* Helper function for c_get_compile_context. Open the GCC front-end |
| 71 | shared library and return the symbol specified by the current |
| 72 | GCC_C_FE_CONTEXT. */ |
| 73 | |
| 74 | static gcc_c_fe_context_function * |
| 75 | load_libcc (void) |
| 76 | { |
| 77 | gcc_c_fe_context_function *func; |
| 78 | |
| 79 | /* gdb_dlopen will call error () on an error, so no need to check |
| 80 | value. */ |
| 81 | gdb_dlhandle_up handle = gdb_dlopen (STRINGIFY (GCC_C_FE_LIBCC)); |
| 82 | func = (gcc_c_fe_context_function *) gdb_dlsym (handle, |
| 83 | STRINGIFY (GCC_C_FE_CONTEXT)); |
| 84 | |
| 85 | if (func == NULL) |
| 86 | error (_("could not find symbol %s in library %s"), |
| 87 | STRINGIFY (GCC_C_FE_CONTEXT), |
| 88 | STRINGIFY (GCC_C_FE_LIBCC)); |
| 89 | |
| 90 | /* Leave the library open. */ |
| 91 | handle.release (); |
| 92 | return func; |
| 93 | } |
| 94 | |
| 95 | /* Return the compile instance associated with the current context. |
| 96 | This function calls the symbol returned from the load_libcc |
| 97 | function. This will provide the gcc_c_context. */ |
| 98 | |
| 99 | compile_instance * |
| 100 | c_get_compile_context (void) |
| 101 | { |
| 102 | static gcc_c_fe_context_function *func; |
| 103 | |
| 104 | struct gcc_c_context *context; |
| 105 | |
| 106 | if (func == NULL) |
| 107 | { |
| 108 | func = load_libcc (); |
| 109 | gdb_assert (func != NULL); |
| 110 | } |
| 111 | |
| 112 | context = (*func) (GCC_FE_VERSION_0, GCC_C_FE_VERSION_0); |
| 113 | if (context == NULL) |
| 114 | error (_("The loaded version of GCC does not support the required version " |
| 115 | "of the API.")); |
| 116 | |
| 117 | return new compile_c_instance (context); |
| 118 | } |
| 119 | |
| 120 | \f |
| 121 | |
| 122 | /* Write one macro definition. */ |
| 123 | |
| 124 | static void |
| 125 | print_one_macro (const char *name, const struct macro_definition *macro, |
| 126 | struct macro_source_file *source, int line, |
| 127 | ui_file *file) |
| 128 | { |
| 129 | /* Don't print command-line defines. They will be supplied another |
| 130 | way. */ |
| 131 | if (line == 0) |
| 132 | return; |
| 133 | |
| 134 | /* None of -Wno-builtin-macro-redefined, #undef first |
| 135 | or plain #define of the same value would avoid a warning. */ |
| 136 | fprintf_filtered (file, "#ifndef %s\n# define %s", name, name); |
| 137 | |
| 138 | if (macro->kind == macro_function_like) |
| 139 | { |
| 140 | int i; |
| 141 | |
| 142 | fputs_filtered ("(", file); |
| 143 | for (i = 0; i < macro->argc; i++) |
| 144 | { |
| 145 | fputs_filtered (macro->argv[i], file); |
| 146 | if (i + 1 < macro->argc) |
| 147 | fputs_filtered (", ", file); |
| 148 | } |
| 149 | fputs_filtered (")", file); |
| 150 | } |
| 151 | |
| 152 | fprintf_filtered (file, " %s\n#endif\n", macro->replacement); |
| 153 | } |
| 154 | |
| 155 | /* Write macro definitions at PC to FILE. */ |
| 156 | |
| 157 | static void |
| 158 | write_macro_definitions (const struct block *block, CORE_ADDR pc, |
| 159 | struct ui_file *file) |
| 160 | { |
| 161 | gdb::unique_xmalloc_ptr<struct macro_scope> scope; |
| 162 | |
| 163 | if (block != NULL) |
| 164 | scope = sal_macro_scope (find_pc_line (pc, 0)); |
| 165 | else |
| 166 | scope = default_macro_scope (); |
| 167 | if (scope == NULL) |
| 168 | scope = user_macro_scope (); |
| 169 | |
| 170 | if (scope != NULL && scope->file != NULL && scope->file->table != NULL) |
| 171 | { |
| 172 | macro_for_each_in_scope (scope->file, scope->line, |
| 173 | [&] (const char *name, |
| 174 | const macro_definition *macro, |
| 175 | macro_source_file *source, |
| 176 | int line) |
| 177 | { |
| 178 | print_one_macro (name, macro, source, line, file); |
| 179 | }); |
| 180 | } |
| 181 | } |
| 182 | |
| 183 | /* Generate a structure holding all the registers used by the function |
| 184 | we're generating. */ |
| 185 | |
| 186 | static void |
| 187 | generate_register_struct (struct ui_file *stream, struct gdbarch *gdbarch, |
| 188 | const unsigned char *registers_used) |
| 189 | { |
| 190 | int i; |
| 191 | int seen = 0; |
| 192 | |
| 193 | fputs_unfiltered ("struct " COMPILE_I_SIMPLE_REGISTER_STRUCT_TAG " {\n", |
| 194 | stream); |
| 195 | |
| 196 | if (registers_used != NULL) |
| 197 | for (i = 0; i < gdbarch_num_regs (gdbarch); ++i) |
| 198 | { |
| 199 | if (registers_used[i]) |
| 200 | { |
| 201 | struct type *regtype = check_typedef (register_type (gdbarch, i)); |
| 202 | std::string regname = compile_register_name_mangled (gdbarch, i); |
| 203 | |
| 204 | seen = 1; |
| 205 | |
| 206 | /* You might think we could use type_print here. However, |
| 207 | target descriptions often use types with names like |
| 208 | "int64_t", which may not be defined in the inferior |
| 209 | (and in any case would not be looked up due to the |
| 210 | #pragma business). So, we take a much simpler |
| 211 | approach: for pointer- or integer-typed registers, emit |
| 212 | the field in the most direct way; and for other |
| 213 | register types (typically flags or vectors), emit a |
| 214 | maximally-aligned array of the correct size. */ |
| 215 | |
| 216 | fputs_unfiltered (" ", stream); |
| 217 | switch (TYPE_CODE (regtype)) |
| 218 | { |
| 219 | case TYPE_CODE_PTR: |
| 220 | fprintf_filtered (stream, "__gdb_uintptr %s", |
| 221 | regname.c_str ()); |
| 222 | break; |
| 223 | |
| 224 | case TYPE_CODE_INT: |
| 225 | { |
| 226 | const char *mode |
| 227 | = c_get_mode_for_size (TYPE_LENGTH (regtype)); |
| 228 | |
| 229 | if (mode != NULL) |
| 230 | { |
| 231 | if (TYPE_UNSIGNED (regtype)) |
| 232 | fputs_unfiltered ("unsigned ", stream); |
| 233 | fprintf_unfiltered (stream, |
| 234 | "int %s" |
| 235 | " __attribute__ ((__mode__(__%s__)))", |
| 236 | regname.c_str (), |
| 237 | mode); |
| 238 | break; |
| 239 | } |
| 240 | } |
| 241 | |
| 242 | /* Fall through. */ |
| 243 | |
| 244 | default: |
| 245 | fprintf_unfiltered (stream, |
| 246 | " unsigned char %s[%d]" |
| 247 | " __attribute__((__aligned__(" |
| 248 | "__BIGGEST_ALIGNMENT__)))", |
| 249 | regname.c_str (), |
| 250 | TYPE_LENGTH (regtype)); |
| 251 | } |
| 252 | fputs_unfiltered (";\n", stream); |
| 253 | } |
| 254 | } |
| 255 | |
| 256 | if (!seen) |
| 257 | fputs_unfiltered (" char " COMPILE_I_SIMPLE_REGISTER_DUMMY ";\n", |
| 258 | stream); |
| 259 | |
| 260 | fputs_unfiltered ("};\n\n", stream); |
| 261 | } |
| 262 | |
| 263 | /* C-language policy to emit a push user expression pragma into BUF. */ |
| 264 | |
| 265 | struct c_push_user_expression |
| 266 | { |
| 267 | void push_user_expression (struct ui_file *buf) |
| 268 | { |
| 269 | fputs_unfiltered ("#pragma GCC user_expression\n", buf); |
| 270 | } |
| 271 | }; |
| 272 | |
| 273 | /* C-language policy to emit a pop user expression pragma into BUF. |
| 274 | For C, this is a nop. */ |
| 275 | |
| 276 | struct pop_user_expression_nop |
| 277 | { |
| 278 | void pop_user_expression (struct ui_file *buf) |
| 279 | { |
| 280 | /* Nothing to do. */ |
| 281 | } |
| 282 | }; |
| 283 | |
| 284 | /* C-language policy to construct a code header for a block of code. |
| 285 | Takes a scope TYPE argument which selects the correct header to |
| 286 | insert into BUF. */ |
| 287 | |
| 288 | struct c_add_code_header |
| 289 | { |
| 290 | void add_code_header (enum compile_i_scope_types type, struct ui_file *buf) |
| 291 | { |
| 292 | switch (type) |
| 293 | { |
| 294 | case COMPILE_I_SIMPLE_SCOPE: |
| 295 | fputs_unfiltered ("void " |
| 296 | GCC_FE_WRAPPER_FUNCTION |
| 297 | " (struct " |
| 298 | COMPILE_I_SIMPLE_REGISTER_STRUCT_TAG |
| 299 | " *" |
| 300 | COMPILE_I_SIMPLE_REGISTER_ARG_NAME |
| 301 | ") {\n", |
| 302 | buf); |
| 303 | break; |
| 304 | |
| 305 | case COMPILE_I_PRINT_ADDRESS_SCOPE: |
| 306 | case COMPILE_I_PRINT_VALUE_SCOPE: |
| 307 | /* <string.h> is needed for a memcpy call below. */ |
| 308 | fputs_unfiltered ("#include <string.h>\n" |
| 309 | "void " |
| 310 | GCC_FE_WRAPPER_FUNCTION |
| 311 | " (struct " |
| 312 | COMPILE_I_SIMPLE_REGISTER_STRUCT_TAG |
| 313 | " *" |
| 314 | COMPILE_I_SIMPLE_REGISTER_ARG_NAME |
| 315 | ", " |
| 316 | COMPILE_I_PRINT_OUT_ARG_TYPE |
| 317 | " " |
| 318 | COMPILE_I_PRINT_OUT_ARG |
| 319 | ") {\n", |
| 320 | buf); |
| 321 | break; |
| 322 | |
| 323 | case COMPILE_I_RAW_SCOPE: |
| 324 | break; |
| 325 | |
| 326 | default: |
| 327 | gdb_assert_not_reached (_("Unknown compiler scope reached.")); |
| 328 | } |
| 329 | } |
| 330 | }; |
| 331 | |
| 332 | /* C-language policy to construct a code footer for a block of code. |
| 333 | Takes a scope TYPE which selects the correct footer to insert into BUF. */ |
| 334 | |
| 335 | struct c_add_code_footer |
| 336 | { |
| 337 | void add_code_footer (enum compile_i_scope_types type, struct ui_file *buf) |
| 338 | { |
| 339 | switch (type) |
| 340 | { |
| 341 | case COMPILE_I_SIMPLE_SCOPE: |
| 342 | case COMPILE_I_PRINT_ADDRESS_SCOPE: |
| 343 | case COMPILE_I_PRINT_VALUE_SCOPE: |
| 344 | fputs_unfiltered ("}\n", buf); |
| 345 | break; |
| 346 | |
| 347 | case COMPILE_I_RAW_SCOPE: |
| 348 | break; |
| 349 | |
| 350 | default: |
| 351 | gdb_assert_not_reached (_("Unknown compiler scope reached.")); |
| 352 | } |
| 353 | } |
| 354 | }; |
| 355 | |
| 356 | /* C-language policy to emit the user code snippet INPUT into BUF based on the |
| 357 | scope TYPE. */ |
| 358 | |
| 359 | struct c_add_input |
| 360 | { |
| 361 | void add_input (enum compile_i_scope_types type, const char *input, |
| 362 | struct ui_file *buf) |
| 363 | { |
| 364 | switch (type) |
| 365 | { |
| 366 | case COMPILE_I_PRINT_ADDRESS_SCOPE: |
| 367 | case COMPILE_I_PRINT_VALUE_SCOPE: |
| 368 | fprintf_unfiltered (buf, |
| 369 | "__auto_type " COMPILE_I_EXPR_VAL " = %s;\n" |
| 370 | "typeof (%s) *" COMPILE_I_EXPR_PTR_TYPE ";\n" |
| 371 | "memcpy (" COMPILE_I_PRINT_OUT_ARG ", %s" |
| 372 | COMPILE_I_EXPR_VAL ",\n" |
| 373 | "sizeof (*" COMPILE_I_EXPR_PTR_TYPE "));\n" |
| 374 | , input, input, |
| 375 | (type == COMPILE_I_PRINT_ADDRESS_SCOPE |
| 376 | ? "&" : "")); |
| 377 | break; |
| 378 | |
| 379 | default: |
| 380 | fputs_unfiltered (input, buf); |
| 381 | break; |
| 382 | } |
| 383 | fputs_unfiltered ("\n", buf); |
| 384 | } |
| 385 | }; |
| 386 | |
| 387 | /* A host class representing a compile program. |
| 388 | |
| 389 | CompileInstanceType is the type of the compile_instance for the |
| 390 | language. |
| 391 | |
| 392 | PushUserExpressionPolicy and PopUserExpressionPolicy are used to |
| 393 | push and pop user expression pragmas to the compile plug-in. |
| 394 | |
| 395 | AddCodeHeaderPolicy and AddCodeFooterPolicy are used to add the appropriate |
| 396 | code header and footer, respectively. |
| 397 | |
| 398 | AddInputPolicy adds the actual user code. */ |
| 399 | |
| 400 | template <class CompileInstanceType, class PushUserExpressionPolicy, |
| 401 | class PopUserExpressionPolicy, class AddCodeHeaderPolicy, |
| 402 | class AddCodeFooterPolicy, class AddInputPolicy> |
| 403 | class compile_program |
| 404 | : private PushUserExpressionPolicy, private PopUserExpressionPolicy, |
| 405 | private AddCodeHeaderPolicy, private AddCodeFooterPolicy, |
| 406 | private AddInputPolicy |
| 407 | { |
| 408 | public: |
| 409 | |
| 410 | /* Construct a compile_program using the compiler instance INST |
| 411 | using the architecture given by GDBARCH. */ |
| 412 | compile_program (CompileInstanceType *inst, struct gdbarch *gdbarch) |
| 413 | : m_instance (inst), m_arch (gdbarch) |
| 414 | { |
| 415 | } |
| 416 | |
| 417 | /* Take the source code provided by the user with the 'compile' |
| 418 | command and compute the additional wrapping, macro, variable and |
| 419 | register operations needed. INPUT is the source code derived from |
| 420 | the 'compile' command, EXPR_BLOCK denotes the block relevant contextually |
| 421 | to the inferior when the expression was created, and EXPR_PC |
| 422 | indicates the value of $PC. |
| 423 | |
| 424 | Returns the text of the program to compile. */ |
| 425 | std::string compute (const char *input, const struct block *expr_block, |
| 426 | CORE_ADDR expr_pc) |
| 427 | { |
| 428 | string_file var_stream; |
| 429 | string_file buf; |
| 430 | |
| 431 | /* Do not generate local variable information for "raw" |
| 432 | compilations. In this case we aren't emitting our own function |
| 433 | and the user's code may only refer to globals. */ |
| 434 | if (m_instance->scope () != COMPILE_I_RAW_SCOPE) |
| 435 | { |
| 436 | /* Generate the code to compute variable locations, but do it |
| 437 | before generating the function header, so we can define the |
| 438 | register struct before the function body. This requires a |
| 439 | temporary stream. */ |
| 440 | gdb::unique_xmalloc_ptr<unsigned char> registers_used |
| 441 | = generate_c_for_variable_locations (m_instance, var_stream, m_arch, |
| 442 | expr_block, expr_pc); |
| 443 | |
| 444 | buf.puts ("typedef unsigned int" |
| 445 | " __attribute__ ((__mode__(__pointer__)))" |
| 446 | " __gdb_uintptr;\n"); |
| 447 | buf.puts ("typedef int" |
| 448 | " __attribute__ ((__mode__(__pointer__)))" |
| 449 | " __gdb_intptr;\n"); |
| 450 | |
| 451 | /* Iterate all log2 sizes in bytes supported by c_get_mode_for_size. */ |
| 452 | for (int i = 0; i < 4; ++i) |
| 453 | { |
| 454 | const char *mode = c_get_mode_for_size (1 << i); |
| 455 | |
| 456 | gdb_assert (mode != NULL); |
| 457 | buf.printf ("typedef int" |
| 458 | " __attribute__ ((__mode__(__%s__)))" |
| 459 | " __gdb_int_%s;\n", |
| 460 | mode, mode); |
| 461 | } |
| 462 | |
| 463 | generate_register_struct (&buf, m_arch, registers_used.get ()); |
| 464 | } |
| 465 | |
| 466 | AddCodeHeaderPolicy::add_code_header (m_instance->scope (), &buf); |
| 467 | |
| 468 | if (m_instance->scope () == COMPILE_I_SIMPLE_SCOPE |
| 469 | || m_instance->scope () == COMPILE_I_PRINT_ADDRESS_SCOPE |
| 470 | || m_instance->scope () == COMPILE_I_PRINT_VALUE_SCOPE) |
| 471 | { |
| 472 | buf.write (var_stream.c_str (), var_stream.size ()); |
| 473 | PushUserExpressionPolicy::push_user_expression (&buf); |
| 474 | } |
| 475 | |
| 476 | write_macro_definitions (expr_block, expr_pc, &buf); |
| 477 | |
| 478 | /* The user expression has to be in its own scope, so that "extern" |
| 479 | works properly. Otherwise gcc thinks that the "extern" |
| 480 | declaration is in the same scope as the declaration provided by |
| 481 | gdb. */ |
| 482 | if (m_instance->scope () != COMPILE_I_RAW_SCOPE) |
| 483 | buf.puts ("{\n"); |
| 484 | |
| 485 | buf.puts ("#line 1 \"gdb command line\"\n"); |
| 486 | |
| 487 | AddInputPolicy::add_input (m_instance->scope (), input, &buf); |
| 488 | |
| 489 | /* For larger user expressions the automatic semicolons may be |
| 490 | confusing. */ |
| 491 | if (strchr (input, '\n') == NULL) |
| 492 | buf.puts (";\n"); |
| 493 | |
| 494 | if (m_instance->scope () != COMPILE_I_RAW_SCOPE) |
| 495 | buf.puts ("}\n"); |
| 496 | |
| 497 | if (m_instance->scope () == COMPILE_I_SIMPLE_SCOPE |
| 498 | || m_instance->scope () == COMPILE_I_PRINT_ADDRESS_SCOPE |
| 499 | || m_instance->scope () == COMPILE_I_PRINT_VALUE_SCOPE) |
| 500 | PopUserExpressionPolicy::pop_user_expression (&buf); |
| 501 | |
| 502 | AddCodeFooterPolicy::add_code_footer (m_instance->scope (), &buf); |
| 503 | return buf.string (); |
| 504 | } |
| 505 | |
| 506 | private: |
| 507 | |
| 508 | /* The compile instance to be used for compilation and |
| 509 | type-conversion. */ |
| 510 | CompileInstanceType *m_instance; |
| 511 | |
| 512 | /* The architecture to be used. */ |
| 513 | struct gdbarch *m_arch; |
| 514 | }; |
| 515 | |
| 516 | /* Type used for C program computations. */ |
| 517 | |
| 518 | typedef compile_program<compile_c_instance, |
| 519 | c_push_user_expression, pop_user_expression_nop, |
| 520 | c_add_code_header, c_add_code_footer, |
| 521 | c_add_input> c_compile_program; |
| 522 | |
| 523 | /* The la_compute_program method for C. */ |
| 524 | |
| 525 | std::string |
| 526 | c_compute_program (compile_instance *inst, |
| 527 | const char *input, |
| 528 | struct gdbarch *gdbarch, |
| 529 | const struct block *expr_block, |
| 530 | CORE_ADDR expr_pc) |
| 531 | { |
| 532 | compile_c_instance *c_inst = static_cast<compile_c_instance *> (inst); |
| 533 | c_compile_program program (c_inst, gdbarch); |
| 534 | |
| 535 | return program.compute (input, expr_block, expr_pc); |
| 536 | } |