gold/yyscript.y

   1 /* yyscript.y -- linker script grammar for gold.  */
   2
   3 /* Copyright 2006, 2007, 2008 Free Software Foundation, Inc.
   4    Written by Ian Lance Taylor <iant@google.com>.
   5
   6    This file is part of gold.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
  21    MA 02110-1301, USA.  */
  22
  23 /* This is a bison grammar to parse a subset of the original GNU ld
  24    linker script language.  */
  25
  26 %{
  27
  28 #include "config.h"
  29
  30 #include <stddef.h>
  31 #include <stdint.h>
  32 #include <stdlib.h>
  33 #include <string.h>
  34
  35 #include "script-c.h"
  36
  37 %}
  38
  39 /* We need to use a pure parser because we might be multi-threaded.
  40    We pass some arguments through the parser to the lexer.  */
  41
  42 %pure-parser
  43
  44 %parse-param {void* closure}
  45 %lex-param {void* closure}
  46
  47 /* Since we require bison anyhow, we take advantage of it.  */
  48
  49 %error-verbose
  50
  51 /* The values associated with tokens.  */
  52
  53 %union {
  54   /* A string.  */
  55   struct Parser_string string;
  56   /* A number.  */
  57   uint64_t integer;
  58   /* An expression.  */
  59   Expression_ptr expr;
  60   /* An output section header.  */
  61   struct Parser_output_section_header output_section_header;
  62   /* An output section trailer.  */
  63   struct Parser_output_section_trailer output_section_trailer;
  64   /* A section constraint.  */
  65   enum Section_constraint constraint;
  66   /* A complete input section specification.  */
  67   struct Input_section_spec input_section_spec;
  68   /* A list of wildcard specifications, with exclusions.  */
  69   struct Wildcard_sections wildcard_sections;
  70   /* A single wildcard specification.  */
  71   struct Wildcard_section wildcard_section;
  72   /* A list of strings.  */
  73   String_list_ptr string_list;
  74   /* Information for a program header.  */
  75   struct Phdr_info phdr_info;
  76   /* Used for version scripts and within VERSION {}.  */
  77   struct Version_dependency_list* deplist;
  78   struct Version_expression_list* versyms;
  79   struct Version_tree* versnode;
  80   enum Script_section_type section_type;
  81 }
  82
  83 /* Operators, including a precedence table for expressions.  */
  84
  85 %right PLUSEQ MINUSEQ MULTEQ DIVEQ '=' LSHIFTEQ RSHIFTEQ ANDEQ OREQ
  86 %right '?' ':'
  87 %left OROR
  88 %left ANDAND
  89 %left '|'
  90 %left '^'
  91 %left '&'
  92 %left EQ NE
  93 %left '<' '>' LE GE
  94 %left LSHIFT RSHIFT
  95 %left '+' '-'
  96 %left '*' '/' '%'
  97
  98 /* A fake operator used to indicate unary operator precedence.  */
  99 %right UNARY
 100
 101 /* Constants.  */
 102
 103 %token <string> STRING
 104 %token <string> QUOTED_STRING
 105 %token <integer> INTEGER
 106
 107 /* Keywords.  This list is taken from ldgram.y and ldlex.l in the old
 108    GNU linker, with the keywords which only appear in MRI mode
 109    removed.  Not all these keywords are actually used in this grammar.
 110    In most cases the keyword is recognized as the token name in upper
 111    case.  The comments indicate where this is not the case.  */
 112
 113 %token ABSOLUTE
 114 %token ADDR
 115 %token ALIGN_K          /* ALIGN */
 116 %token ALIGNOF
 117 %token ASSERT_K         /* ASSERT */
 118 %token AS_NEEDED
 119 %token AT
 120 %token BIND
 121 %token BLOCK
 122 %token BYTE
 123 %token CONSTANT
 124 %token CONSTRUCTORS
 125 %token COPY
 126 %token CREATE_OBJECT_SYMBOLS
 127 %token DATA_SEGMENT_ALIGN
 128 %token DATA_SEGMENT_END
 129 %token DATA_SEGMENT_RELRO_END
 130 %token DEFINED
 131 %token DSECT
 132 %token ENTRY
 133 %token EXCLUDE_FILE
 134 %token EXTERN
 135 %token FILL
 136 %token FLOAT
 137 %token FORCE_COMMON_ALLOCATION
 138 %token GLOBAL           /* global */
 139 %token GROUP
 140 %token HLL
 141 %token INCLUDE
 142 %token INHIBIT_COMMON_ALLOCATION
 143 %token INFO
 144 %token INPUT
 145 %token KEEP
 146 %token LENGTH           /* LENGTH, l, len */
 147 %token LOADADDR
 148 %token LOCAL            /* local */
 149 %token LONG
 150 %token MAP
 151 %token MAX_K            /* MAX */
 152 %token MEMORY
 153 %token MIN_K            /* MIN */
 154 %token NEXT
 155 %token NOCROSSREFS
 156 %token NOFLOAT
 157 %token NOLOAD
 158 %token ONLY_IF_RO
 159 %token ONLY_IF_RW
 160 %token ORIGIN           /* ORIGIN, o, org */
 161 %token OUTPUT
 162 %token OUTPUT_ARCH
 163 %token OUTPUT_FORMAT
 164 %token OVERLAY
 165 %token PHDRS
 166 %token PROVIDE
 167 %token PROVIDE_HIDDEN
 168 %token QUAD
 169 %token SEARCH_DIR
 170 %token SECTIONS
 171 %token SEGMENT_START
 172 %token SHORT
 173 %token SIZEOF
 174 %token SIZEOF_HEADERS   /* SIZEOF_HEADERS, sizeof_headers */
 175 %token SORT_BY_ALIGNMENT
 176 %token SORT_BY_NAME
 177 %token SPECIAL
 178 %token SQUAD
 179 %token STARTUP
 180 %token SUBALIGN
 181 %token SYSLIB
 182 %token TARGET_K         /* TARGET */
 183 %token TRUNCATE
 184 %token VERSIONK         /* VERSION */
 185
 186 /* Keywords, part 2.  These are keywords that are unique to gold,
 187    and not present in the old GNU linker.  As before, unless the
 188    comments say otherwise, the keyword is recognized as the token
 189    name in upper case. */
 190
 191 %token OPTION
 192
 193 /* Special tokens used to tell the grammar what type of tokens we are
 194    parsing.  The token stream always begins with one of these tokens.
 195    We do this because version scripts can appear embedded within
 196    linker scripts, and because --defsym uses the expression
 197    parser.  */
 198 %token PARSING_LINKER_SCRIPT
 199 %token PARSING_VERSION_SCRIPT
 200 %token PARSING_DEFSYM
 201 %token PARSING_DYNAMIC_LIST
 202
 203 /* Non-terminal types, where needed.  */
 204
 205 %type <expr> parse_exp exp
 206 %type <expr> opt_at opt_align opt_subalign opt_fill
 207 %type <output_section_header> section_header opt_address_and_section_type
 208 %type <section_type> section_type
 209 %type <output_section_trailer> section_trailer
 210 %type <constraint> opt_constraint
 211 %type <string_list> opt_phdr
 212 %type <integer> data_length
 213 %type <input_section_spec> input_section_no_keep
 214 %type <wildcard_sections> wildcard_sections
 215 %type <wildcard_section> wildcard_file wildcard_section
 216 %type <string_list> exclude_names
 217 %type <string> wildcard_name
 218 %type <integer> phdr_type
 219 %type <phdr_info> phdr_info
 220 %type <versyms> vers_defns
 221 %type <versnode> vers_tag
 222 %type <deplist> verdep
 223 %type <string> string
 224
 225 %%
 226
 227 /* Read the special token to see what to read next.  */
 228 top:
 229           PARSING_LINKER_SCRIPT linker_script
 230         | PARSING_VERSION_SCRIPT version_script
 231         | PARSING_DEFSYM defsym_expr
 232         | PARSING_DYNAMIC_LIST dynamic_list_expr
 233         ;
 234
 235 /* A file contains a list of commands.  */
 236 linker_script:
 237           linker_script file_cmd
 238         | /* empty */
 239         ;
 240
 241 /* A command which may appear at top level of a linker script.  */
 242 file_cmd:
 243           EXTERN '(' extern_name_list ')'
 244         | FORCE_COMMON_ALLOCATION
 245             { script_set_common_allocation(closure, 1); }
 246         | GROUP
 247             { script_start_group(closure); }
 248           '(' input_list ')'
 249             { script_end_group(closure); }
 250         | INHIBIT_COMMON_ALLOCATION
 251             { script_set_common_allocation(closure, 0); }
 252         | INPUT '(' input_list ')'
 253         | OPTION '(' string ')'
 254             { script_parse_option(closure, $3.value, $3.length); }
 255         | OUTPUT_FORMAT '(' string ')'
 256             {
 257               if (!script_check_output_format(closure, $3.value, $3.length,
 258                                               NULL, 0, NULL, 0))
 259                 YYABORT;
 260             }
 261         | OUTPUT_FORMAT '(' string ',' string ',' string ')'
 262             {
 263               if (!script_check_output_format(closure, $3.value, $3.length,
 264                                               $5.value, $5.length,
 265                                               $7.value, $7.length))
 266                 YYABORT;
 267             }
 268         | PHDRS '{' phdrs_defs '}'
 269         | SEARCH_DIR '(' string ')'
 270             { script_add_search_dir(closure, $3.value, $3.length); }
 271         | SECTIONS '{'
 272             { script_start_sections(closure); }
 273           sections_block '}'
 274             { script_finish_sections(closure); }
 275         | TARGET_K '(' string ')'
 276             { script_set_target(closure, $3.value, $3.length); }
 277         | VERSIONK '{'
 278             { script_push_lex_into_version_mode(closure); }
 279           version_script '}'
 280             { script_pop_lex_mode(closure); }
 281         | file_or_sections_cmd
 282         | ignore_cmd
 283         | ';'
 284         ;
 285
 286 /* Top level commands which we ignore.  The GNU linker uses these to
 287    select the output format, but we don't offer a choice.  Ignoring
 288    these is more-or-less OK since most scripts simply explicitly
 289    choose the default.  */
 290 ignore_cmd:
 291           OUTPUT_ARCH '(' string ')'
 292         ;
 293
 294 /* A list of external undefined symbols.  We put the lexer into
 295    expression mode so that commas separate names; this is what the GNU
 296    linker does.  */
 297
 298 extern_name_list:
 299             { script_push_lex_into_expression_mode(closure); }
 300           extern_name_list_body
 301             { script_pop_lex_mode(closure); }
 302         ;
 303
 304 extern_name_list_body:
 305           string
 306             { script_add_extern(closure, $1.value, $1.length); }
 307         | extern_name_list_body string
 308             { script_add_extern(closure, $2.value, $2.length); }
 309         | extern_name_list_body ',' string
 310             { script_add_extern(closure, $3.value, $3.length); }
 311         ;
 312
 313 /* A list of input file names.  */
 314 input_list:
 315           input_list_element
 316         | input_list opt_comma input_list_element
 317         ;
 318
 319 /* An input file name.  */
 320 input_list_element:
 321           string
 322             { script_add_file(closure, $1.value, $1.length); }
 323         | '-' STRING
 324             { script_add_library(closure, $2.value, $2.length); }
 325         | AS_NEEDED
 326             { script_start_as_needed(closure); }
 327           '(' input_list ')'
 328             { script_end_as_needed(closure); }
 329         ;
 330
 331 /* Commands in a SECTIONS block.  */
 332 sections_block:
 333           sections_block section_block_cmd
 334         | /* empty */
 335         ;
 336
 337 /* A command which may appear within a SECTIONS block.  */
 338 section_block_cmd:
 339           file_or_sections_cmd
 340         | string section_header
 341             { script_start_output_section(closure, $1.value, $1.length, &$2); }
 342           '{' section_cmds '}' section_trailer
 343             { script_finish_output_section(closure, &$7); }
 344         ;
 345
 346 /* The header of an output section in a SECTIONS block--everything
 347    after the name.  */
 348 section_header:
 349             { script_push_lex_into_expression_mode(closure); }
 350           opt_address_and_section_type opt_at opt_align opt_subalign
 351             { script_pop_lex_mode(closure); }
 352           opt_constraint
 353             {
 354               $$.address = $2.address;
 355               $$.section_type = $2.section_type;
 356               $$.load_address = $3;
 357               $$.align = $4;
 358               $$.subalign = $5;
 359               $$.constraint = $7;
 360             }
 361         ;
 362
 363 /* The optional address followed by the optional section type.  This
 364    is a separate nonterminal to avoid a shift/reduce conflict on
 365    '(' in section_header.  */
 366
 367 opt_address_and_section_type:
 368         ':'
 369             {
 370               $$.address = NULL;
 371               $$.section_type = SCRIPT_SECTION_TYPE_NONE;
 372             }
 373         | '(' ')' ':'
 374             {
 375               $$.address = NULL;
 376               $$.section_type = SCRIPT_SECTION_TYPE_NONE;
 377             }
 378         | exp ':'
 379             {
 380               $$.address = $1;
 381               $$.section_type = SCRIPT_SECTION_TYPE_NONE;
 382             }
 383         | exp '(' ')' ':'
 384             {
 385               $$.address = $1;
 386               $$.section_type = SCRIPT_SECTION_TYPE_NONE;
 387             }
 388         | '(' section_type ')' ':'
 389             {
 390               $$.address = NULL;
 391               $$.section_type = $2;
 392             }
 393         | exp '(' section_type ')' ':'
 394             {
 395               $$.address = $1;
 396               $$.section_type = $3;
 397             }
 398         ;
 399
 400 /* We only support NOLOAD.  */
 401 section_type:
 402         NOLOAD
 403             { $$ = SCRIPT_SECTION_TYPE_NOLOAD; }
 404         | DSECT
 405             {
 406               yyerror(closure, "DSECT section type is unsupported");
 407               $$ = SCRIPT_SECTION_TYPE_DSECT;
 408             }
 409         | COPY
 410             {
 411               yyerror(closure, "COPY section type is unsupported");
 412               $$ = SCRIPT_SECTION_TYPE_COPY;
 413             }
 414         | INFO
 415             {
 416               yyerror(closure, "INFO section type is unsupported");
 417               $$ = SCRIPT_SECTION_TYPE_INFO;
 418             }
 419         | OVERLAY
 420             {
 421               yyerror(closure, "OVERLAY section type is unsupported");
 422               $$ = SCRIPT_SECTION_TYPE_OVERLAY;
 423             }
 424         ;
 425
 426 /* The address at which an output section should be loaded.  */
 427 opt_at:
 428           /* empty */
 429             { $$ = NULL; }
 430         | AT '(' exp ')'
 431             { $$ = $3; }
 432         ;
 433
 434 /* The alignment of an output section.  */
 435 opt_align:
 436           /* empty */
 437             { $$ = NULL; }
 438         | ALIGN_K '(' exp ')'
 439             { $$ = $3; }
 440         ;
 441
 442 /* The input section alignment within an output section.  */
 443 opt_subalign:
 444           /* empty */
 445             { $$ = NULL; }
 446         | SUBALIGN '(' exp ')'
 447             { $$ = $3; }
 448         ;
 449
 450 /* A section constraint.  */
 451 opt_constraint:
 452           /* empty */
 453             { $$ = CONSTRAINT_NONE; }
 454         | ONLY_IF_RO
 455             { $$ = CONSTRAINT_ONLY_IF_RO; }
 456         | ONLY_IF_RW
 457             { $$ = CONSTRAINT_ONLY_IF_RW; }
 458         | SPECIAL
 459             { $$ = CONSTRAINT_SPECIAL; }
 460         ;
 461
 462 /* The trailer of an output section in a SECTIONS block.  */
 463 section_trailer:
 464           opt_memspec opt_at_memspec opt_phdr opt_fill opt_comma
 465             {
 466               $$.fill = $4;
 467               $$.phdrs = $3;
 468             }
 469         ;
 470
 471 /* A memory specification for an output section.  */
 472 opt_memspec:
 473           '>' string
 474             { yyerror(closure, "memory regions are not supported"); }
 475         | /* empty */
 476         ;
 477
 478 /* A memory specification for where to load an output section.  */
 479 opt_at_memspec:
 480           AT '>' string
 481             { yyerror(closure, "memory regions are not supported"); }
 482         | /* empty */
 483         ;
 484
 485 /* The program segment an output section should go into.  */
 486 opt_phdr:
 487           opt_phdr ':' string
 488             { $$ = script_string_list_push_back($1, $3.value, $3.length); }
 489         | /* empty */
 490             { $$ = NULL; }
 491         ;
 492
 493 /* The value to use to fill an output section.  FIXME: This does not
 494    handle a string of arbitrary length.  */
 495 opt_fill:
 496           '=' parse_exp
 497             { $$ = $2; }
 498         | /* empty */
 499             { $$ = NULL; }
 500         ;
 501
 502 /* Commands which may appear within the description of an output
 503    section in a SECTIONS block.  */
 504 section_cmds:
 505           /* empty */
 506         | section_cmds section_cmd
 507         ;
 508
 509 /* A command which may appear within the description of an output
 510    section in a SECTIONS block.  */
 511 section_cmd:
 512           assignment end
 513         | input_section_spec
 514         | data_length '(' parse_exp ')'
 515             { script_add_data(closure, $1, $3); }
 516         | ASSERT_K '(' parse_exp ',' string ')'
 517             { script_add_assertion(closure, $3, $5.value, $5.length); }
 518         | FILL '(' parse_exp ')'
 519             { script_add_fill(closure, $3); }
 520         | CONSTRUCTORS
 521             {
 522               /* The GNU linker uses CONSTRUCTORS for the a.out object
 523                  file format.  It does nothing when using ELF.  Since
 524                  some ELF linker scripts use it although it does
 525                  nothing, we accept it and ignore it.  */
 526             }
 527         | SORT_BY_NAME '(' CONSTRUCTORS ')'
 528         | ';'
 529         ;
 530
 531 /* The length of data which may appear within the description of an
 532    output section in a SECTIONS block.  */
 533 data_length:
 534           QUAD
 535             { $$ = QUAD; }
 536         | SQUAD
 537             { $$ = SQUAD; }
 538         | LONG
 539             { $$ = LONG; }
 540         | SHORT
 541             { $$ = SHORT; }
 542         | BYTE
 543             { $$ = BYTE; }
 544         ;
 545
 546 /* An input section specification.  This may appear within the
 547    description of an output section in a SECTIONS block.  */
 548 input_section_spec:
 549           input_section_no_keep
 550             { script_add_input_section(closure, &$1, 0); }
 551         | KEEP '(' input_section_no_keep ')'
 552             { script_add_input_section(closure, &$3, 1); }
 553         ;
 554
 555 /* An input section specification within a KEEP clause.  */
 556 input_section_no_keep:
 557           string
 558             {
 559               $$.file.name = $1;
 560               $$.file.sort = SORT_WILDCARD_NONE;
 561               $$.input_sections.sections = NULL;
 562               $$.input_sections.exclude = NULL;
 563             }
 564         | wildcard_file '(' wildcard_sections ')'
 565             {
 566               $$.file = $1;
 567               $$.input_sections = $3;
 568             }
 569         ;
 570
 571 /* A wildcard file specification.  */
 572 wildcard_file:
 573           wildcard_name
 574             {
 575               $$.name = $1;
 576               $$.sort = SORT_WILDCARD_NONE;
 577             }
 578         | SORT_BY_NAME '(' wildcard_name ')'
 579             {
 580               $$.name = $3;
 581               $$.sort = SORT_WILDCARD_BY_NAME;
 582             }
 583         ;
 584
 585 /* A list of wild card section specifications.  */
 586 wildcard_sections:
 587           wildcard_sections opt_comma wildcard_section
 588             {
 589               $$.sections = script_string_sort_list_add($1.sections, &$3);
 590               $$.exclude = $1.exclude;
 591             }
 592         | wildcard_section
 593             {
 594               $$.sections = script_new_string_sort_list(&$1);
 595               $$.exclude = NULL;
 596             }
 597         | wildcard_sections opt_comma EXCLUDE_FILE '(' exclude_names ')'
 598             {
 599               $$.sections = $1.sections;
 600               $$.exclude = script_string_list_append($1.exclude, $5);
 601             }
 602         | EXCLUDE_FILE '(' exclude_names ')'
 603             {
 604               $$.sections = NULL;
 605               $$.exclude = $3;
 606             }
 607         ;
 608
 609 /* A single wild card specification.  */
 610 wildcard_section:
 611           wildcard_name
 612             {
 613               $$.name = $1;
 614               $$.sort = SORT_WILDCARD_NONE;
 615             }
 616         | SORT_BY_NAME '(' wildcard_section ')'
 617             {
 618               $$.name = $3.name;
 619               switch ($3.sort)
 620                 {
 621                 case SORT_WILDCARD_NONE:
 622                   $$.sort = SORT_WILDCARD_BY_NAME;
 623                   break;
 624                 case SORT_WILDCARD_BY_NAME:
 625                 case SORT_WILDCARD_BY_NAME_BY_ALIGNMENT:
 626                   break;
 627                 case SORT_WILDCARD_BY_ALIGNMENT:
 628                 case SORT_WILDCARD_BY_ALIGNMENT_BY_NAME:
 629                   $$.sort = SORT_WILDCARD_BY_NAME_BY_ALIGNMENT;
 630                   break;
 631                 default:
 632                   abort();
 633                 }
 634             }
 635         | SORT_BY_ALIGNMENT '(' wildcard_section ')'
 636             {
 637               $$.name = $3.name;
 638               switch ($3.sort)
 639                 {
 640                 case SORT_WILDCARD_NONE:
 641                   $$.sort = SORT_WILDCARD_BY_ALIGNMENT;
 642                   break;
 643                 case SORT_WILDCARD_BY_ALIGNMENT:
 644                 case SORT_WILDCARD_BY_ALIGNMENT_BY_NAME:
 645                   break;
 646                 case SORT_WILDCARD_BY_NAME:
 647                 case SORT_WILDCARD_BY_NAME_BY_ALIGNMENT:
 648                   $$.sort = SORT_WILDCARD_BY_ALIGNMENT_BY_NAME;
 649                   break;
 650                 default:
 651                   abort();
 652                 }
 653             }
 654         ;
 655
 656 /* A list of file names to exclude.  */
 657 exclude_names:
 658           exclude_names opt_comma wildcard_name
 659             { $$ = script_string_list_push_back($1, $3.value, $3.length); }
 660         | wildcard_name
 661             { $$ = script_new_string_list($1.value, $1.length); }
 662         ;
 663
 664 /* A single wildcard name.  We recognize '*' and '?' specially since
 665    they are expression tokens.  */
 666 wildcard_name:
 667           string
 668             { $$ = $1; }
 669         | '*'
 670             {
 671               $$.value = "*";
 672               $$.length = 1;
 673             }
 674         | '?'
 675             {
 676               $$.value = "?";
 677               $$.length = 1;
 678             }
 679         ;
 680
 681 /* A command which may appear at the top level of a linker script, or
 682    within a SECTIONS block.  */
 683 file_or_sections_cmd:
 684           ENTRY '(' string ')'
 685             { script_set_entry(closure, $3.value, $3.length); }
 686         | assignment end
 687         | ASSERT_K '(' parse_exp ',' string ')'
 688             { script_add_assertion(closure, $3, $5.value, $5.length); }
 689         ;
 690
 691 /* A list of program header definitions.  */
 692 phdrs_defs:
 693           phdrs_defs phdr_def
 694         | /* empty */
 695         ;
 696
 697 /* A program header definition.  */
 698 phdr_def:
 699           string phdr_type phdr_info ';'
 700             { script_add_phdr(closure, $1.value, $1.length, $2, &$3); }
 701         ;
 702
 703 /* A program header type.  The GNU linker accepts a general expression
 704    here, but that would be a pain because we would have to dig into
 705    the expression structure.  It's unlikely that anybody uses anything
 706    other than a string or a number here, so that is all we expect.  */
 707 phdr_type:
 708           string
 709             { $$ = script_phdr_string_to_type(closure, $1.value, $1.length); }
 710         | INTEGER
 711             { $$ = $1; }
 712         ;
 713
 714 /* Additional information for a program header.  */
 715 phdr_info:
 716           /* empty */
 717             { memset(&$$, 0, sizeof(struct Phdr_info)); }
 718         | string phdr_info
 719             {
 720               $$ = $2;
 721               if ($1.length == 7 && strncmp($1.value, "FILEHDR", 7) == 0)
 722                 $$.includes_filehdr = 1;
 723               else
 724                 yyerror(closure, "PHDRS syntax error");
 725             }
 726         | PHDRS phdr_info
 727             {
 728               $$ = $2;
 729               $$.includes_phdrs = 1;
 730             }
 731         | string '(' INTEGER ')' phdr_info
 732             {
 733               $$ = $5;
 734               if ($1.length == 5 && strncmp($1.value, "FLAGS", 5) == 0)
 735                 {
 736                   $$.is_flags_valid = 1;
 737                   $$.flags = $3;
 738                 }
 739               else
 740                 yyerror(closure, "PHDRS syntax error");
 741             }
 742         | AT '(' parse_exp ')' phdr_info
 743             {
 744               $$ = $5;
 745               $$.load_address = $3;
 746             }
 747         ;
 748
 749 /* Set a symbol to a value.  */
 750 assignment:
 751           string '=' parse_exp
 752             { script_set_symbol(closure, $1.value, $1.length, $3, 0, 0); }
 753         | string PLUSEQ parse_exp
 754             {
 755               Expression_ptr s = script_exp_string($1.value, $1.length);
 756               Expression_ptr e = script_exp_binary_add(s, $3);
 757               script_set_symbol(closure, $1.value, $1.length, e, 0, 0);
 758             }
 759         | string MINUSEQ parse_exp
 760             {
 761               Expression_ptr s = script_exp_string($1.value, $1.length);
 762               Expression_ptr e = script_exp_binary_sub(s, $3);
 763               script_set_symbol(closure, $1.value, $1.length, e, 0, 0);
 764             }
 765         | string MULTEQ parse_exp
 766             {
 767               Expression_ptr s = script_exp_string($1.value, $1.length);
 768               Expression_ptr e = script_exp_binary_mult(s, $3);
 769               script_set_symbol(closure, $1.value, $1.length, e, 0, 0);
 770             }
 771         | string DIVEQ parse_exp
 772             {
 773               Expression_ptr s = script_exp_string($1.value, $1.length);
 774               Expression_ptr e = script_exp_binary_div(s, $3);
 775               script_set_symbol(closure, $1.value, $1.length, e, 0, 0);
 776             }
 777         | string LSHIFTEQ parse_exp
 778             {
 779               Expression_ptr s = script_exp_string($1.value, $1.length);
 780               Expression_ptr e = script_exp_binary_lshift(s, $3);
 781               script_set_symbol(closure, $1.value, $1.length, e, 0, 0);
 782             }
 783         | string RSHIFTEQ parse_exp
 784             {
 785               Expression_ptr s = script_exp_string($1.value, $1.length);
 786               Expression_ptr e = script_exp_binary_rshift(s, $3);
 787               script_set_symbol(closure, $1.value, $1.length, e, 0, 0);
 788             }
 789         | string ANDEQ parse_exp
 790             {
 791               Expression_ptr s = script_exp_string($1.value, $1.length);
 792               Expression_ptr e = script_exp_binary_bitwise_and(s, $3);
 793               script_set_symbol(closure, $1.value, $1.length, e, 0, 0);
 794             }
 795         | string OREQ parse_exp
 796             {
 797               Expression_ptr s = script_exp_string($1.value, $1.length);
 798               Expression_ptr e = script_exp_binary_bitwise_or(s, $3);
 799               script_set_symbol(closure, $1.value, $1.length, e, 0, 0);
 800             }
 801         | PROVIDE '(' string '=' parse_exp ')'
 802             { script_set_symbol(closure, $3.value, $3.length, $5, 1, 0); }
 803         | PROVIDE_HIDDEN '(' string '=' parse_exp ')'
 804             { script_set_symbol(closure, $3.value, $3.length, $5, 1, 1); }
 805         ;
 806
 807 /* Parse an expression, putting the lexer into the right mode.  */
 808 parse_exp:
 809             { script_push_lex_into_expression_mode(closure); }
 810           exp
 811             {
 812               script_pop_lex_mode(closure);
 813               $$ = $2;
 814             }
 815         ;
 816
 817 /* An expression.  */
 818 exp:
 819           '(' exp ')'
 820             { $$ = $2; }
 821         | '-' exp %prec UNARY
 822             { $$ = script_exp_unary_minus($2); }
 823         | '!' exp %prec UNARY
 824             { $$ = script_exp_unary_logical_not($2); }
 825         | '~' exp %prec UNARY
 826             { $$ = script_exp_unary_bitwise_not($2); }
 827         | '+' exp %prec UNARY
 828             { $$ = $2; }
 829         | exp '*' exp
 830             { $$ = script_exp_binary_mult($1, $3); }
 831         | exp '/' exp
 832             { $$ = script_exp_binary_div($1, $3); }
 833         | exp '%' exp
 834             { $$ = script_exp_binary_mod($1, $3); }
 835         | exp '+' exp
 836             { $$ = script_exp_binary_add($1, $3); }
 837         | exp '-' exp
 838             { $$ = script_exp_binary_sub($1, $3); }
 839         | exp LSHIFT exp
 840             { $$ = script_exp_binary_lshift($1, $3); }
 841         | exp RSHIFT exp
 842             { $$ = script_exp_binary_rshift($1, $3); }
 843         | exp EQ exp
 844             { $$ = script_exp_binary_eq($1, $3); }
 845         | exp NE exp
 846             { $$ = script_exp_binary_ne($1, $3); }
 847         | exp LE exp
 848             { $$ = script_exp_binary_le($1, $3); }
 849         | exp GE exp
 850             { $$ = script_exp_binary_ge($1, $3); }
 851         | exp '<' exp
 852             { $$ = script_exp_binary_lt($1, $3); }
 853         | exp '>' exp
 854             { $$ = script_exp_binary_gt($1, $3); }
 855         | exp '&' exp
 856             { $$ = script_exp_binary_bitwise_and($1, $3); }
 857         | exp '^' exp
 858             { $$ = script_exp_binary_bitwise_xor($1, $3); }
 859         | exp '|' exp
 860             { $$ = script_exp_binary_bitwise_or($1, $3); }
 861         | exp ANDAND exp
 862             { $$ = script_exp_binary_logical_and($1, $3); }
 863         | exp OROR exp
 864             { $$ = script_exp_binary_logical_or($1, $3); }
 865         | exp '?' exp ':' exp
 866             { $$ = script_exp_trinary_cond($1, $3, $5); }
 867         | INTEGER
 868             { $$ = script_exp_integer($1); }
 869         | string
 870             { $$ = script_exp_string($1.value, $1.length); }
 871         | MAX_K '(' exp ',' exp ')'
 872             { $$ = script_exp_function_max($3, $5); }
 873         | MIN_K '(' exp ',' exp ')'
 874             { $$ = script_exp_function_min($3, $5); }
 875         | DEFINED '(' string ')'
 876             { $$ = script_exp_function_defined($3.value, $3.length); }
 877         | SIZEOF_HEADERS
 878             { $$ = script_exp_function_sizeof_headers(); }
 879         | ALIGNOF '(' string ')'
 880             { $$ = script_exp_function_alignof($3.value, $3.length); }
 881         | SIZEOF '(' string ')'
 882             { $$ = script_exp_function_sizeof($3.value, $3.length); }
 883         | ADDR '(' string ')'
 884             { $$ = script_exp_function_addr($3.value, $3.length); }
 885         | LOADADDR '(' string ')'
 886             { $$ = script_exp_function_loadaddr($3.value, $3.length); }
 887         | ORIGIN '(' string ')'
 888             { $$ = script_exp_function_origin($3.value, $3.length); }
 889         | LENGTH '(' string ')'
 890             { $$ = script_exp_function_length($3.value, $3.length); }
 891         | CONSTANT '(' string ')'
 892             { $$ = script_exp_function_constant($3.value, $3.length); }
 893         | ABSOLUTE '(' exp ')'
 894             { $$ = script_exp_function_absolute($3); }
 895         | ALIGN_K '(' exp ')'
 896             { $$ = script_exp_function_align(script_exp_string(".", 1), $3); }
 897         | ALIGN_K '(' exp ',' exp ')'
 898             { $$ = script_exp_function_align($3, $5); }
 899         | BLOCK '(' exp ')'
 900             { $$ = script_exp_function_align(script_exp_string(".", 1), $3); }
 901         | DATA_SEGMENT_ALIGN '(' exp ',' exp ')'
 902             {
 903               script_data_segment_align(closure);
 904               $$ = script_exp_function_data_segment_align($3, $5);
 905             }
 906         | DATA_SEGMENT_RELRO_END '(' exp ',' exp ')'
 907             {
 908               script_data_segment_relro_end(closure);
 909               $$ = script_exp_function_data_segment_relro_end($3, $5);
 910             }
 911         | DATA_SEGMENT_END '(' exp ')'
 912             { $$ = script_exp_function_data_segment_end($3); }
 913         | SEGMENT_START '(' string ',' exp ')'
 914             {
 915               $$ = script_exp_function_segment_start($3.value, $3.length, $5);
 916               /* We need to take note of any SEGMENT_START expressions
 917                  because they change the behaviour of -Ttext, -Tdata and
 918                  -Tbss options.  */
 919               script_saw_segment_start_expression(closure);
 920             }
 921         | ASSERT_K '(' exp ',' string ')'
 922             { $$ = script_exp_function_assert($3, $5.value, $5.length); }
 923         ;
 924
 925 /* Handle the --defsym option.  */
 926 defsym_expr:
 927           string '=' parse_exp
 928             { script_set_symbol(closure, $1.value, $1.length, $3, 0, 0); }
 929         ;
 930
 931 /* Handle the --dynamic-list option.  A dynamic list has the format
 932    { sym1; sym2; extern "C++" { namespace::sym3 }; };
 933    We store the symbol we see in the "local" list; that is where
 934    Command_line::in_dynamic_list() will look to do its check.
 935    TODO(csilvers): More than one of these brace-lists can appear, and
 936    should just be merged and treated as a single list.  */
 937 dynamic_list_expr: dynamic_list_nodes ;
 938
 939 dynamic_list_nodes:
 940           dynamic_list_node
 941         | dynamic_list_nodes dynamic_list_node
 942         ;
 943
 944 dynamic_list_node:
 945           '{' vers_defns ';' '}' ';'
 946             { script_new_vers_node (closure, NULL, $2); }
 947         ;
 948
 949 /* A version script.  */
 950 version_script:
 951           vers_nodes
 952         ;
 953
 954 vers_nodes:
 955           vers_node
 956         | vers_nodes vers_node
 957         ;
 958
 959 vers_node:
 960           '{' vers_tag '}' ';'
 961             {
 962               script_register_vers_node (closure, NULL, 0, $2, NULL);
 963             }
 964         | string '{' vers_tag '}' ';'
 965             {
 966               script_register_vers_node (closure, $1.value, $1.length, $3,
 967                                          NULL);
 968             }
 969         | string '{' vers_tag '}' verdep ';'
 970             {
 971               script_register_vers_node (closure, $1.value, $1.length, $3, $5);
 972             }
 973         ;
 974
 975 verdep:
 976           string
 977             {
 978               $$ = script_add_vers_depend (closure, NULL, $1.value, $1.length);
 979             }
 980         | verdep string
 981             {
 982               $$ = script_add_vers_depend (closure, $1, $2.value, $2.length);
 983             }
 984         ;
 985
 986 vers_tag:
 987           /* empty */
 988             { $$ = script_new_vers_node (closure, NULL, NULL); }
 989         | vers_defns ';'
 990             { $$ = script_new_vers_node (closure, $1, NULL); }
 991         | GLOBAL ':' vers_defns ';'
 992             { $$ = script_new_vers_node (closure, $3, NULL); }
 993         | LOCAL ':' vers_defns ';'
 994             { $$ = script_new_vers_node (closure, NULL, $3); }
 995         | GLOBAL ':' vers_defns ';' LOCAL ':' vers_defns ';'
 996             { $$ = script_new_vers_node (closure, $3, $7); }
 997         ;
 998
 999 /* Here is one of the rare places we care about the distinction
1000    between STRING and QUOTED_STRING.  For QUOTED_STRING, we do exact
1001    matching on the pattern, so we pass in true for the exact_match
1002    parameter.  For STRING, we do glob matching and pass in false.  */
1003 vers_defns:
1004           STRING
1005             {
1006               $$ = script_new_vers_pattern (closure, NULL, $1.value,
1007                                             $1.length, 0);
1008             }
1009         | QUOTED_STRING
1010             {
1011               $$ = script_new_vers_pattern (closure, NULL, $1.value,
1012                                             $1.length, 1);
1013             }
1014         | vers_defns ';' STRING
1015             {
1016               $$ = script_new_vers_pattern (closure, $1, $3.value,
1017                                             $3.length, 0);
1018             }
1019         | vers_defns ';' QUOTED_STRING
1020             {
1021               $$ = script_new_vers_pattern (closure, $1, $3.value,
1022                                             $3.length, 1);
1023             }
1024         | /* Push string on the language stack. */
1025           EXTERN string '{'
1026             { version_script_push_lang (closure, $2.value, $2.length); }
1027           vers_defns opt_semicolon '}'
1028             {
1029               $$ = $5;
1030               version_script_pop_lang(closure);
1031             }
1032         | /* Push string on the language stack.  This is more complicated
1033              than the other cases because we need to merge the linked-list
1034              state from the pre-EXTERN defns and the post-EXTERN defns.  */
1035           vers_defns ';' EXTERN string '{'
1036             { version_script_push_lang (closure, $4.value, $4.length); }
1037           vers_defns opt_semicolon '}'
1038             {
1039               $$ = script_merge_expressions ($1, $7);
1040               version_script_pop_lang(closure);
1041             }
1042         | EXTERN  // "extern" as a symbol name
1043             {
1044               $$ = script_new_vers_pattern (closure, NULL, "extern",
1045                                             sizeof("extern") - 1, 1);
1046             }
1047         | vers_defns ';' EXTERN
1048             {
1049               $$ = script_new_vers_pattern (closure, $1, "extern",
1050                                             sizeof("extern") - 1, 1);
1051             }
1052         ;
1053
1054 /* A string can be either a STRING or a QUOTED_STRING.  Almost all the
1055    time we don't care, and we use this rule.  */
1056 string:
1057           STRING
1058             { $$ = $1; }
1059         | QUOTED_STRING
1060             { $$ = $1; }
1061         ;
1062
1063 /* Some statements require a terminator, which may be a semicolon or a
1064    comma.  */
1065 end:
1066           ';'
1067         | ','
1068         ;
1069
1070 /* An optional semicolon.  */
1071 opt_semicolon:
1072           ';'
1073         |  /* empty */
1074         ;
1075
1076 /* An optional comma.  */
1077 opt_comma:
1078           ','
1079         | /* empty */
1080         ;
1081
1082 %%