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 LEN
147%token LENGTH		/* LENGTH, l, len */
148%token LOADADDR
149%token LOCAL		/* local */
150%token LONG
151%token MAP
152%token MAX_K		/* MAX */
153%token MEMORY
154%token MIN_K		/* MIN */
155%token NEXT
156%token NOCROSSREFS
157%token NOFLOAT
158%token NOLOAD
159%token ONLY_IF_RO
160%token ONLY_IF_RW
161%token ORG
162%token ORIGIN		/* ORIGIN, o, org */
163%token OUTPUT
164%token OUTPUT_ARCH
165%token OUTPUT_FORMAT
166%token OVERLAY
167%token PHDRS
168%token PROVIDE
169%token PROVIDE_HIDDEN
170%token QUAD
171%token SEARCH_DIR
172%token SECTIONS
173%token SEGMENT_START
174%token SHORT
175%token SIZEOF
176%token SIZEOF_HEADERS	/* SIZEOF_HEADERS, sizeof_headers */
177%token SORT_BY_ALIGNMENT
178%token SORT_BY_NAME
179%token SPECIAL
180%token SQUAD
181%token STARTUP
182%token SUBALIGN
183%token SYSLIB
184%token TARGET_K		/* TARGET */
185%token TRUNCATE
186%token VERSIONK		/* VERSION */
187
188/* Keywords, part 2.  These are keywords that are unique to gold,
189   and not present in the old GNU linker.  As before, unless the
190   comments say otherwise, the keyword is recognized as the token
191   name in upper case. */
192
193%token OPTION
194
195/* Special tokens used to tell the grammar what type of tokens we are
196   parsing.  The token stream always begins with one of these tokens.
197   We do this because version scripts can appear embedded within
198   linker scripts, and because --defsym uses the expression
199   parser.  */
200%token PARSING_LINKER_SCRIPT
201%token PARSING_VERSION_SCRIPT
202%token PARSING_DEFSYM
203%token PARSING_DYNAMIC_LIST
204
205/* Non-terminal types, where needed.  */
206
207%type <expr> parse_exp exp
208%type <expr> opt_at opt_align opt_subalign opt_fill
209%type <output_section_header> section_header opt_address_and_section_type
210%type <section_type> section_type
211%type <output_section_trailer> section_trailer
212%type <constraint> opt_constraint
213%type <string_list> opt_phdr
214%type <integer> data_length
215%type <input_section_spec> input_section_no_keep
216%type <wildcard_sections> wildcard_sections
217%type <wildcard_section> wildcard_file wildcard_section
218%type <string_list> exclude_names
219%type <string> wildcard_name
220%type <integer> phdr_type memory_attr
221%type <phdr_info> phdr_info
222%type <versyms> vers_defns
223%type <versnode> vers_tag
224%type <deplist> verdep
225%type <string> string
226
227%%
228
229/* Read the special token to see what to read next.  */
230top:
231	  PARSING_LINKER_SCRIPT linker_script
232	| PARSING_VERSION_SCRIPT version_script
233	| PARSING_DEFSYM defsym_expr
234        | PARSING_DYNAMIC_LIST dynamic_list_expr
235	;
236
237/* A file contains a list of commands.  */
238linker_script:
239	  linker_script file_cmd
240	| /* empty */
241	;
242
243/* A command which may appear at top level of a linker script.  */
244file_cmd:
245	  EXTERN '(' extern_name_list ')'
246	| FORCE_COMMON_ALLOCATION
247	    { script_set_common_allocation(closure, 1); }
248	| GROUP
249	    { script_start_group(closure); }
250	  '(' input_list ')'
251	    { script_end_group(closure); }
252	| INHIBIT_COMMON_ALLOCATION
253	    { script_set_common_allocation(closure, 0); }
254	| INPUT '(' input_list ')'
255	| MEMORY '{' memory_defs '}'
256        | OPTION '(' string ')'
257	    { script_parse_option(closure, $3.value, $3.length); }
258	| OUTPUT_FORMAT '(' string ')'
259	    {
260	      if (!script_check_output_format(closure, $3.value, $3.length,
261					      NULL, 0, NULL, 0))
262		YYABORT;
263	    }
264	| OUTPUT_FORMAT '(' string ',' string ',' string ')'
265	    {
266	      if (!script_check_output_format(closure, $3.value, $3.length,
267					      $5.value, $5.length,
268					      $7.value, $7.length))
269		YYABORT;
270	    }
271	| PHDRS '{' phdrs_defs '}'
272	| SEARCH_DIR '(' string ')'
273	    { script_add_search_dir(closure, $3.value, $3.length); }
274	| SECTIONS '{'
275	    { script_start_sections(closure); }
276	  sections_block '}'
277	    { script_finish_sections(closure); }
278	| TARGET_K '(' string ')'
279	    { script_set_target(closure, $3.value, $3.length); }
280        | VERSIONK '{'
281            { script_push_lex_into_version_mode(closure); }
282          version_script '}'
283            { script_pop_lex_mode(closure); }
284	| file_or_sections_cmd
285	| ignore_cmd
286	| ';'
287	;
288
289/* Top level commands which we ignore.  The GNU linker uses these to
290   select the output format, but we don't offer a choice.  Ignoring
291   these is more-or-less OK since most scripts simply explicitly
292   choose the default.  */
293ignore_cmd:
294	  OUTPUT_ARCH '(' string ')'
295	;
296
297/* A list of external undefined symbols.  We put the lexer into
298   expression mode so that commas separate names; this is what the GNU
299   linker does.  */
300
301extern_name_list:
302	    { script_push_lex_into_expression_mode(closure); }
303	  extern_name_list_body
304	    { script_pop_lex_mode(closure); }
305	;
306
307extern_name_list_body:
308	  string
309	    { script_add_extern(closure, $1.value, $1.length); }
310	| extern_name_list_body string
311	    { script_add_extern(closure, $2.value, $2.length); }
312	| extern_name_list_body ',' string
313	    { script_add_extern(closure, $3.value, $3.length); }
314	;
315
316/* A list of input file names.  */
317input_list:
318	  input_list_element
319	| input_list opt_comma input_list_element
320	;
321
322/* An input file name.  */
323input_list_element:
324	  string
325	    { script_add_file(closure, $1.value, $1.length); }
326	| '-' STRING
327	    { script_add_library(closure, $2.value, $2.length); }
328	| AS_NEEDED
329	    { script_start_as_needed(closure); }
330	  '(' input_list ')'
331	    { script_end_as_needed(closure); }
332	;
333
334/* Commands in a SECTIONS block.  */
335sections_block:
336	  sections_block section_block_cmd
337	| /* empty */
338	;
339
340/* A command which may appear within a SECTIONS block.  */
341section_block_cmd:
342	  file_or_sections_cmd
343	| string section_header
344	    { script_start_output_section(closure, $1.value, $1.length, &$2); }
345	  '{' section_cmds '}' section_trailer
346	    { script_finish_output_section(closure, &$7); }
347	;
348
349/* The header of an output section in a SECTIONS block--everything
350   after the name.  */
351section_header:
352	    { script_push_lex_into_expression_mode(closure); }
353	  opt_address_and_section_type opt_at opt_align opt_subalign
354	    { script_pop_lex_mode(closure); }
355	  opt_constraint
356	    {
357	      $$.address = $2.address;
358	      $$.section_type = $2.section_type;
359	      $$.load_address = $3;
360	      $$.align = $4;
361	      $$.subalign = $5;
362	      $$.constraint = $7;
363	    }
364	;
365
366/* The optional address followed by the optional section type.  This
367   is a separate nonterminal to avoid a shift/reduce conflict on
368   '(' in section_header.  */
369
370opt_address_and_section_type:
371	':'
372	    {
373	      $$.address = NULL;
374	      $$.section_type = SCRIPT_SECTION_TYPE_NONE;
375	    }
376	| '(' ')' ':'
377	    {
378	      $$.address = NULL;
379	      $$.section_type = SCRIPT_SECTION_TYPE_NONE;
380	    }
381	| exp ':'
382	    {
383	      $$.address = $1;
384	      $$.section_type = SCRIPT_SECTION_TYPE_NONE;
385	    }
386	| exp '(' ')' ':'
387	    {
388	      $$.address = $1;
389	      $$.section_type = SCRIPT_SECTION_TYPE_NONE;
390	    }
391	| '(' section_type ')' ':'
392	    {
393	      $$.address = NULL;
394	      $$.section_type = $2;
395	    }
396	| exp '(' section_type ')' ':'
397	    {
398	      $$.address = $1;
399	      $$.section_type = $3;
400	    }
401	;
402
403/* We only support NOLOAD.  */
404section_type:
405	NOLOAD
406	    { $$ = SCRIPT_SECTION_TYPE_NOLOAD; }
407	| DSECT
408	    {
409	      yyerror(closure, "DSECT section type is unsupported");
410	      $$ = SCRIPT_SECTION_TYPE_DSECT;
411	    }
412	| COPY
413	    {
414	      yyerror(closure, "COPY section type is unsupported");
415	      $$ = SCRIPT_SECTION_TYPE_COPY;
416	    }
417	| INFO
418	    {
419	      yyerror(closure, "INFO section type is unsupported");
420	      $$ = SCRIPT_SECTION_TYPE_INFO;
421	    }
422	| OVERLAY
423	    {
424	      yyerror(closure, "OVERLAY section type is unsupported");
425	      $$ = SCRIPT_SECTION_TYPE_OVERLAY;
426	    }
427	;
428
429/* The address at which an output section should be loaded.  */
430opt_at:
431	  /* empty */
432	    { $$ = NULL; }
433	| AT '(' exp ')'
434	    { $$ = $3; }
435	;
436
437/* The alignment of an output section.  */
438opt_align:
439	  /* empty */
440	    { $$ = NULL; }
441	| ALIGN_K '(' exp ')'
442	    { $$ = $3; }
443	;
444
445/* The input section alignment within an output section.  */
446opt_subalign:
447	  /* empty */
448	    { $$ = NULL; }
449	| SUBALIGN '(' exp ')'
450	    { $$ = $3; }
451	;
452
453/* A section constraint.  */
454opt_constraint:
455	  /* empty */
456	    { $$ = CONSTRAINT_NONE; }
457	| ONLY_IF_RO
458	    { $$ = CONSTRAINT_ONLY_IF_RO; }
459	| ONLY_IF_RW
460	    { $$ = CONSTRAINT_ONLY_IF_RW; }
461	| SPECIAL
462	    { $$ = CONSTRAINT_SPECIAL; }
463	;
464
465/* The trailer of an output section in a SECTIONS block.  */
466section_trailer:
467	  opt_memspec opt_at_memspec opt_phdr opt_fill opt_comma
468	    {
469	      $$.fill = $4;
470	      $$.phdrs = $3;
471	    }
472	;
473
474/* A memory specification for an output section.  */
475opt_memspec:
476	  '>' string
477	    { script_set_section_region(closure, $2.value, $2.length, 1); }
478	| /* empty */
479	;
480
481/* A memory specification for where to load an output section.  */
482opt_at_memspec:
483	  AT '>' string
484	    { script_set_section_region(closure, $3.value, $3.length, 0); }
485	| /* empty */
486	;
487
488/* The program segment an output section should go into.  */
489opt_phdr:
490	  opt_phdr ':' string
491	    { $$ = script_string_list_push_back($1, $3.value, $3.length); }
492	| /* empty */
493	    { $$ = NULL; }
494	;
495
496/* The value to use to fill an output section.  FIXME: This does not
497   handle a string of arbitrary length.  */
498opt_fill:
499	  '=' parse_exp
500	    { $$ = $2; }
501	| /* empty */
502	    { $$ = NULL; }
503	;
504
505/* Commands which may appear within the description of an output
506   section in a SECTIONS block.  */
507section_cmds:
508	  /* empty */
509	| section_cmds section_cmd
510	;
511
512/* A command which may appear within the description of an output
513   section in a SECTIONS block.  */
514section_cmd:
515	  assignment end
516	| input_section_spec
517	| data_length '(' parse_exp ')'
518	    { script_add_data(closure, $1, $3); }
519	| ASSERT_K '(' parse_exp ',' string ')'
520	    { script_add_assertion(closure, $3, $5.value, $5.length); }
521	| FILL '(' parse_exp ')'
522	    { script_add_fill(closure, $3); }
523	| CONSTRUCTORS
524	    {
525	      /* The GNU linker uses CONSTRUCTORS for the a.out object
526		 file format.  It does nothing when using ELF.  Since
527		 some ELF linker scripts use it although it does
528		 nothing, we accept it and ignore it.  */
529	    }
530	| SORT_BY_NAME '(' CONSTRUCTORS ')'
531	| ';'
532	;
533
534/* The length of data which may appear within the description of an
535   output section in a SECTIONS block.  */
536data_length:
537	  QUAD
538	    { $$ = QUAD; }
539	| SQUAD
540	    { $$ = SQUAD; }
541	| LONG
542	    { $$ = LONG; }
543	| SHORT
544	    { $$ = SHORT; }
545	| BYTE
546	    { $$ = BYTE; }
547	;
548
549/* An input section specification.  This may appear within the
550   description of an output section in a SECTIONS block.  */
551input_section_spec:
552	  input_section_no_keep
553	    { script_add_input_section(closure, &$1, 0); }
554	| KEEP '(' input_section_no_keep ')'
555	    { script_add_input_section(closure, &$3, 1); }
556	;
557
558/* An input section specification within a KEEP clause.  */
559input_section_no_keep:
560	  string
561	    {
562	      $$.file.name = $1;
563	      $$.file.sort = SORT_WILDCARD_NONE;
564	      $$.input_sections.sections = NULL;
565	      $$.input_sections.exclude = NULL;
566	    }
567	| wildcard_file '(' wildcard_sections ')'
568	    {
569	      $$.file = $1;
570	      $$.input_sections = $3;
571	    }
572	;
573
574/* A wildcard file specification.  */
575wildcard_file:
576	  wildcard_name
577	    {
578	      $$.name = $1;
579	      $$.sort = SORT_WILDCARD_NONE;
580	    }
581	| SORT_BY_NAME '(' wildcard_name ')'
582	    {
583	      $$.name = $3;
584	      $$.sort = SORT_WILDCARD_BY_NAME;
585	    }
586	;
587
588/* A list of wild card section specifications.  */
589wildcard_sections:
590	  wildcard_sections opt_comma wildcard_section
591	    {
592	      $$.sections = script_string_sort_list_add($1.sections, &$3);
593	      $$.exclude = $1.exclude;
594	    }
595	| wildcard_section
596	    {
597	      $$.sections = script_new_string_sort_list(&$1);
598	      $$.exclude = NULL;
599	    }
600	| wildcard_sections opt_comma EXCLUDE_FILE '(' exclude_names ')'
601	    {
602	      $$.sections = $1.sections;
603	      $$.exclude = script_string_list_append($1.exclude, $5);
604	    }
605	| EXCLUDE_FILE '(' exclude_names ')'
606	    {
607	      $$.sections = NULL;
608	      $$.exclude = $3;
609	    }
610	;
611
612/* A single wild card specification.  */
613wildcard_section:
614	  wildcard_name
615	    {
616	      $$.name = $1;
617	      $$.sort = SORT_WILDCARD_NONE;
618	    }
619	| SORT_BY_NAME '(' wildcard_section ')'
620	    {
621	      $$.name = $3.name;
622	      switch ($3.sort)
623		{
624		case SORT_WILDCARD_NONE:
625		  $$.sort = SORT_WILDCARD_BY_NAME;
626		  break;
627		case SORT_WILDCARD_BY_NAME:
628		case SORT_WILDCARD_BY_NAME_BY_ALIGNMENT:
629		  break;
630		case SORT_WILDCARD_BY_ALIGNMENT:
631		case SORT_WILDCARD_BY_ALIGNMENT_BY_NAME:
632		  $$.sort = SORT_WILDCARD_BY_NAME_BY_ALIGNMENT;
633		  break;
634		default:
635		  abort();
636		}
637	    }
638	| SORT_BY_ALIGNMENT '(' wildcard_section ')'
639	    {
640	      $$.name = $3.name;
641	      switch ($3.sort)
642		{
643		case SORT_WILDCARD_NONE:
644		  $$.sort = SORT_WILDCARD_BY_ALIGNMENT;
645		  break;
646		case SORT_WILDCARD_BY_ALIGNMENT:
647		case SORT_WILDCARD_BY_ALIGNMENT_BY_NAME:
648		  break;
649		case SORT_WILDCARD_BY_NAME:
650		case SORT_WILDCARD_BY_NAME_BY_ALIGNMENT:
651		  $$.sort = SORT_WILDCARD_BY_ALIGNMENT_BY_NAME;
652		  break;
653		default:
654		  abort();
655		}
656	    }
657	;
658
659/* A list of file names to exclude.  */
660exclude_names:
661	  exclude_names opt_comma wildcard_name
662	    { $$ = script_string_list_push_back($1, $3.value, $3.length); }
663	| wildcard_name
664	    { $$ = script_new_string_list($1.value, $1.length); }
665	;
666
667/* A single wildcard name.  We recognize '*' and '?' specially since
668   they are expression tokens.  */
669wildcard_name:
670	  string
671	    { $$ = $1; }
672	| '*'
673	    {
674	      $$.value = "*";
675	      $$.length = 1;
676	    }
677	| '?'
678	    {
679	      $$.value = "?";
680	      $$.length = 1;
681	    }
682	;
683
684/* A command which may appear at the top level of a linker script, or
685   within a SECTIONS block.  */
686file_or_sections_cmd:
687	  ENTRY '(' string ')'
688	    { script_set_entry(closure, $3.value, $3.length); }
689	| assignment end
690	| ASSERT_K '(' parse_exp ',' string ')'
691	    { script_add_assertion(closure, $3, $5.value, $5.length); }
692	;
693
694/* A list of MEMORY definitions.  */
695memory_defs:
696	  memory_defs opt_comma memory_def
697	| /* empty */
698	;
699
700/* A single MEMORY definition.  */
701memory_def:
702	  string memory_attr ':' memory_origin '=' parse_exp opt_comma memory_length '=' parse_exp
703	  { script_add_memory(closure, $1.value, $1.length, $2, $6, $10); }
704	|
705	  /* LD supports an INCLUDE directive here, currently GOLD does not.  */
706	  INCLUDE string
707	  { script_include_directive(closure, $2.value, $2.length); }
708	|
709	;
710
711/* The (optional) attributes of a MEMORY region.  */
712memory_attr:
713	  '(' string ')'
714	  { $$ = script_parse_memory_attr(closure, $2.value, $2.length, 0); }
715        | /* Inverted attributes. */
716	  '(' '!' string ')'
717	  { $$ = script_parse_memory_attr(closure, $3.value, $3.length, 1); }
718	| /* empty */
719	    { $$ = 0; }
720	;
721
722memory_origin:
723          ORIGIN
724	|
725	  ORG
726	|
727	  'o'
728	;
729
730memory_length:
731          LENGTH
732	|
733	  LEN
734	|
735	  'l'
736	;
737
738/* A list of program header definitions.  */
739phdrs_defs:
740	  phdrs_defs phdr_def
741	| /* empty */
742	;
743
744/* A program header definition.  */
745phdr_def:
746	  string phdr_type phdr_info ';'
747	    { script_add_phdr(closure, $1.value, $1.length, $2, &$3); }
748	;
749
750/* A program header type.  The GNU linker accepts a general expression
751   here, but that would be a pain because we would have to dig into
752   the expression structure.  It's unlikely that anybody uses anything
753   other than a string or a number here, so that is all we expect.  */
754phdr_type:
755	  string
756	    { $$ = script_phdr_string_to_type(closure, $1.value, $1.length); }
757	| INTEGER
758	    { $$ = $1; }
759	;
760
761/* Additional information for a program header.  */
762phdr_info:
763	  /* empty */
764	    { memset(&$$, 0, sizeof(struct Phdr_info)); }
765	| string phdr_info
766	    {
767	      $$ = $2;
768	      if ($1.length == 7 && strncmp($1.value, "FILEHDR", 7) == 0)
769		$$.includes_filehdr = 1;
770	      else
771		yyerror(closure, "PHDRS syntax error");
772	    }
773	| PHDRS phdr_info
774	    {
775	      $$ = $2;
776	      $$.includes_phdrs = 1;
777	    }
778	| string '(' INTEGER ')' phdr_info
779	    {
780	      $$ = $5;
781	      if ($1.length == 5 && strncmp($1.value, "FLAGS", 5) == 0)
782		{
783		  $$.is_flags_valid = 1;
784		  $$.flags = $3;
785		}
786	      else
787		yyerror(closure, "PHDRS syntax error");
788	    }
789	| AT '(' parse_exp ')' phdr_info
790	    {
791	      $$ = $5;
792	      $$.load_address = $3;
793	    }
794	;
795
796/* Set a symbol to a value.  */
797assignment:
798	  string '=' parse_exp
799	    { script_set_symbol(closure, $1.value, $1.length, $3, 0, 0); }
800	| string PLUSEQ parse_exp
801	    {
802	      Expression_ptr s = script_exp_string($1.value, $1.length);
803	      Expression_ptr e = script_exp_binary_add(s, $3);
804	      script_set_symbol(closure, $1.value, $1.length, e, 0, 0);
805	    }
806	| string MINUSEQ parse_exp
807	    {
808	      Expression_ptr s = script_exp_string($1.value, $1.length);
809	      Expression_ptr e = script_exp_binary_sub(s, $3);
810	      script_set_symbol(closure, $1.value, $1.length, e, 0, 0);
811	    }
812	| string MULTEQ parse_exp
813	    {
814	      Expression_ptr s = script_exp_string($1.value, $1.length);
815	      Expression_ptr e = script_exp_binary_mult(s, $3);
816	      script_set_symbol(closure, $1.value, $1.length, e, 0, 0);
817	    }
818	| string DIVEQ parse_exp
819	    {
820	      Expression_ptr s = script_exp_string($1.value, $1.length);
821	      Expression_ptr e = script_exp_binary_div(s, $3);
822	      script_set_symbol(closure, $1.value, $1.length, e, 0, 0);
823	    }
824	| string LSHIFTEQ parse_exp
825	    {
826	      Expression_ptr s = script_exp_string($1.value, $1.length);
827	      Expression_ptr e = script_exp_binary_lshift(s, $3);
828	      script_set_symbol(closure, $1.value, $1.length, e, 0, 0);
829	    }
830	| string RSHIFTEQ parse_exp
831	    {
832	      Expression_ptr s = script_exp_string($1.value, $1.length);
833	      Expression_ptr e = script_exp_binary_rshift(s, $3);
834	      script_set_symbol(closure, $1.value, $1.length, e, 0, 0);
835	    }
836	| string ANDEQ parse_exp
837	    {
838	      Expression_ptr s = script_exp_string($1.value, $1.length);
839	      Expression_ptr e = script_exp_binary_bitwise_and(s, $3);
840	      script_set_symbol(closure, $1.value, $1.length, e, 0, 0);
841	    }
842	| string OREQ parse_exp
843	    {
844	      Expression_ptr s = script_exp_string($1.value, $1.length);
845	      Expression_ptr e = script_exp_binary_bitwise_or(s, $3);
846	      script_set_symbol(closure, $1.value, $1.length, e, 0, 0);
847	    }
848	| PROVIDE '(' string '=' parse_exp ')'
849	    { script_set_symbol(closure, $3.value, $3.length, $5, 1, 0); }
850	| PROVIDE_HIDDEN '(' string '=' parse_exp ')'
851	    { script_set_symbol(closure, $3.value, $3.length, $5, 1, 1); }
852	;
853
854/* Parse an expression, putting the lexer into the right mode.  */
855parse_exp:
856	    { script_push_lex_into_expression_mode(closure); }
857	  exp
858	    {
859	      script_pop_lex_mode(closure);
860	      $$ = $2;
861	    }
862	;
863
864/* An expression.  */
865exp:
866	  '(' exp ')'
867	    { $$ = $2; }
868	| '-' exp %prec UNARY
869	    { $$ = script_exp_unary_minus($2); }
870	| '!' exp %prec UNARY
871	    { $$ = script_exp_unary_logical_not($2); }
872	| '~' exp %prec UNARY
873	    { $$ = script_exp_unary_bitwise_not($2); }
874	| '+' exp %prec UNARY
875	    { $$ = $2; }
876	| exp '*' exp
877	    { $$ = script_exp_binary_mult($1, $3); }
878	| exp '/' exp
879	    { $$ = script_exp_binary_div($1, $3); }
880	| exp '%' exp
881	    { $$ = script_exp_binary_mod($1, $3); }
882	| exp '+' exp
883	    { $$ = script_exp_binary_add($1, $3); }
884	| exp '-' exp
885	    { $$ = script_exp_binary_sub($1, $3); }
886	| exp LSHIFT exp
887	    { $$ = script_exp_binary_lshift($1, $3); }
888	| exp RSHIFT exp
889	    { $$ = script_exp_binary_rshift($1, $3); }
890	| exp EQ exp
891	    { $$ = script_exp_binary_eq($1, $3); }
892	| exp NE exp
893	    { $$ = script_exp_binary_ne($1, $3); }
894	| exp LE exp
895	    { $$ = script_exp_binary_le($1, $3); }
896	| exp GE exp
897	    { $$ = script_exp_binary_ge($1, $3); }
898	| exp '<' exp
899	    { $$ = script_exp_binary_lt($1, $3); }
900	| exp '>' exp
901	    { $$ = script_exp_binary_gt($1, $3); }
902	| exp '&' exp
903	    { $$ = script_exp_binary_bitwise_and($1, $3); }
904	| exp '^' exp
905	    { $$ = script_exp_binary_bitwise_xor($1, $3); }
906	| exp '|' exp
907	    { $$ = script_exp_binary_bitwise_or($1, $3); }
908	| exp ANDAND exp
909	    { $$ = script_exp_binary_logical_and($1, $3); }
910	| exp OROR exp
911	    { $$ = script_exp_binary_logical_or($1, $3); }
912	| exp '?' exp ':' exp
913	    { $$ = script_exp_trinary_cond($1, $3, $5); }
914	| INTEGER
915	    { $$ = script_exp_integer($1); }
916	| string
917	    { $$ = script_symbol(closure, $1.value, $1.length); }
918	| MAX_K '(' exp ',' exp ')'
919	    { $$ = script_exp_function_max($3, $5); }
920	| MIN_K '(' exp ',' exp ')'
921	    { $$ = script_exp_function_min($3, $5); }
922	| DEFINED '(' string ')'
923	    { $$ = script_exp_function_defined($3.value, $3.length); }
924	| SIZEOF_HEADERS
925	    { $$ = script_exp_function_sizeof_headers(); }
926	| ALIGNOF '(' string ')'
927	    { $$ = script_exp_function_alignof($3.value, $3.length); }
928	| SIZEOF '(' string ')'
929	    { $$ = script_exp_function_sizeof($3.value, $3.length); }
930	| ADDR '(' string ')'
931	    { $$ = script_exp_function_addr($3.value, $3.length); }
932	| LOADADDR '(' string ')'
933	    { $$ = script_exp_function_loadaddr($3.value, $3.length); }
934	| ORIGIN '(' string ')'
935	    { $$ = script_exp_function_origin(closure, $3.value, $3.length); }
936	| LENGTH '(' string ')'
937	    { $$ = script_exp_function_length(closure, $3.value, $3.length); }
938	| CONSTANT '(' string ')'
939	    { $$ = script_exp_function_constant($3.value, $3.length); }
940	| ABSOLUTE '(' exp ')'
941	    { $$ = script_exp_function_absolute($3); }
942	| ALIGN_K '(' exp ')'
943	    { $$ = script_exp_function_align(script_exp_string(".", 1), $3); }
944	| ALIGN_K '(' exp ',' exp ')'
945	    { $$ = script_exp_function_align($3, $5); }
946	| BLOCK '(' exp ')'
947	    { $$ = script_exp_function_align(script_exp_string(".", 1), $3); }
948	| DATA_SEGMENT_ALIGN '(' exp ',' exp ')'
949	    {
950	      script_data_segment_align(closure);
951	      $$ = script_exp_function_data_segment_align($3, $5);
952	    }
953	| DATA_SEGMENT_RELRO_END '(' exp ',' exp ')'
954	    {
955	      script_data_segment_relro_end(closure);
956	      $$ = script_exp_function_data_segment_relro_end($3, $5);
957	    }
958	| DATA_SEGMENT_END '(' exp ')'
959	    { $$ = script_exp_function_data_segment_end($3); }
960	| SEGMENT_START '(' string ',' exp ')'
961	    {
962	      $$ = script_exp_function_segment_start($3.value, $3.length, $5);
963	      /* We need to take note of any SEGMENT_START expressions
964		 because they change the behaviour of -Ttext, -Tdata and
965		 -Tbss options.  */
966	      script_saw_segment_start_expression(closure);
967	    }
968	| ASSERT_K '(' exp ',' string ')'
969	    { $$ = script_exp_function_assert($3, $5.value, $5.length); }
970	;
971
972/* Handle the --defsym option.  */
973defsym_expr:
974	  string '=' parse_exp
975	    { script_set_symbol(closure, $1.value, $1.length, $3, 0, 0); }
976	;
977
978/* Handle the --dynamic-list option.  A dynamic list has the format
979   { sym1; sym2; extern "C++" { namespace::sym3 }; };
980   We store the symbol we see in the "local" list; that is where
981   Command_line::in_dynamic_list() will look to do its check.
982   TODO(csilvers): More than one of these brace-lists can appear, and
983   should just be merged and treated as a single list.  */
984dynamic_list_expr: dynamic_list_nodes ;
985
986dynamic_list_nodes:
987	  dynamic_list_node
988	| dynamic_list_nodes dynamic_list_node
989        ;
990
991dynamic_list_node:
992          '{' vers_defns ';' '}' ';'
993            { script_new_vers_node (closure, NULL, $2); }
994        ;
995
996/* A version script.  */
997version_script:
998	  vers_nodes
999	;
1000
1001vers_nodes:
1002	  vers_node
1003	| vers_nodes vers_node
1004	;
1005
1006vers_node:
1007	  '{' vers_tag '}' ';'
1008	    {
1009	      script_register_vers_node (closure, NULL, 0, $2, NULL);
1010	    }
1011	| string '{' vers_tag '}' ';'
1012	    {
1013	      script_register_vers_node (closure, $1.value, $1.length, $3,
1014					 NULL);
1015	    }
1016	| string '{' vers_tag '}' verdep ';'
1017	    {
1018	      script_register_vers_node (closure, $1.value, $1.length, $3, $5);
1019	    }
1020	;
1021
1022verdep:
1023	  string
1024	    {
1025	      $$ = script_add_vers_depend (closure, NULL, $1.value, $1.length);
1026	    }
1027	| verdep string
1028	    {
1029	      $$ = script_add_vers_depend (closure, $1, $2.value, $2.length);
1030	    }
1031	;
1032
1033vers_tag:
1034	  /* empty */
1035	    { $$ = script_new_vers_node (closure, NULL, NULL); }
1036	| vers_defns ';'
1037	    { $$ = script_new_vers_node (closure, $1, NULL); }
1038	| GLOBAL ':' vers_defns ';'
1039	    { $$ = script_new_vers_node (closure, $3, NULL); }
1040	| LOCAL ':' vers_defns ';'
1041	    { $$ = script_new_vers_node (closure, NULL, $3); }
1042	| GLOBAL ':' vers_defns ';' LOCAL ':' vers_defns ';'
1043	    { $$ = script_new_vers_node (closure, $3, $7); }
1044	;
1045
1046/* Here is one of the rare places we care about the distinction
1047   between STRING and QUOTED_STRING.  For QUOTED_STRING, we do exact
1048   matching on the pattern, so we pass in true for the exact_match
1049   parameter.  For STRING, we do glob matching and pass in false.  */
1050vers_defns:
1051	  STRING
1052	    {
1053	      $$ = script_new_vers_pattern (closure, NULL, $1.value,
1054					    $1.length, 0);
1055	    }
1056	| QUOTED_STRING
1057	    {
1058	      $$ = script_new_vers_pattern (closure, NULL, $1.value,
1059					    $1.length, 1);
1060	    }
1061	| vers_defns ';' STRING
1062	    {
1063	      $$ = script_new_vers_pattern (closure, $1, $3.value,
1064                                            $3.length, 0);
1065	    }
1066	| vers_defns ';' QUOTED_STRING
1067	    {
1068	      $$ = script_new_vers_pattern (closure, $1, $3.value,
1069                                            $3.length, 1);
1070	    }
1071        | /* Push string on the language stack. */
1072          EXTERN string '{'
1073	    { version_script_push_lang (closure, $2.value, $2.length); }
1074	  vers_defns opt_semicolon '}'
1075	    {
1076	      $$ = $5;
1077	      version_script_pop_lang(closure);
1078	    }
1079        | /* Push string on the language stack.  This is more complicated
1080             than the other cases because we need to merge the linked-list
1081             state from the pre-EXTERN defns and the post-EXTERN defns.  */
1082          vers_defns ';' EXTERN string '{'
1083	    { version_script_push_lang (closure, $4.value, $4.length); }
1084	  vers_defns opt_semicolon '}'
1085	    {
1086	      $$ = script_merge_expressions ($1, $7);
1087	      version_script_pop_lang(closure);
1088	    }
1089        | EXTERN  // "extern" as a symbol name
1090	    {
1091	      $$ = script_new_vers_pattern (closure, NULL, "extern",
1092					    sizeof("extern") - 1, 1);
1093	    }
1094	| vers_defns ';' EXTERN
1095	    {
1096	      $$ = script_new_vers_pattern (closure, $1, "extern",
1097					    sizeof("extern") - 1, 1);
1098	    }
1099	;
1100
1101/* A string can be either a STRING or a QUOTED_STRING.  Almost all the
1102   time we don't care, and we use this rule.  */
1103string:
1104          STRING
1105	    { $$ = $1; }
1106	| QUOTED_STRING
1107	    { $$ = $1; }
1108	;
1109
1110/* Some statements require a terminator, which may be a semicolon or a
1111   comma.  */
1112end:
1113	  ';'
1114	| ','
1115	;
1116
1117/* An optional semicolon.  */
1118opt_semicolon:
1119	  ';'
1120	|  /* empty */
1121	;
1122
1123/* An optional comma.  */
1124opt_comma:
1125	  ','
1126	| /* empty */
1127	;
1128
1129%%
1130