1 /* This module handles expression trees.
2 Copyright (C) 1991-2022 Free Software Foundation, Inc.
5 This file is part of the GNU Binutils.
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.
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.
17 You should have received a copy of the GNU General Public License
18 along with this program; if not, write to the Free Software
19 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
20 MA 02110-1301, USA. */
23 /* This module is in charge of working out the contents of expressions.
25 It has to keep track of the relative/absness of a symbol etc. This
26 is done by keeping all values in a struct (an etree_value_type)
27 which contains a value, a section to which it is relative and a
42 #include "libiberty.h"
43 #include "safe-ctype.h"
45 static void exp_fold_tree_1 (etree_type *);
46 static bfd_vma align_n (bfd_vma, bfd_vma);
48 segment_type *segments;
50 struct ldexp_control expld;
52 /* This structure records symbols for which we need to keep track of
53 definedness for use in the DEFINED () test. It is also used in
54 making absolute symbols section relative late in the link. */
56 struct definedness_hash_entry
58 struct bfd_hash_entry root;
60 /* If this symbol was assigned from "dot" outside of an output
61 section statement, the section we'd like it relative to. */
64 /* Low bits of iteration count. Symbols with matching iteration have
65 been defined in this pass over the script. */
66 unsigned int iteration : 8;
68 /* Symbol was defined by an object file. */
69 unsigned int by_object : 1;
72 static struct bfd_hash_table definedness_table;
74 /* Print the string representation of the given token. Surround it
75 with spaces if INFIX_P is TRUE. */
78 exp_print_token (token_code_type code, int infix_p)
105 { LOG2CEIL, "LOG2CEIL" },
106 { ALIGN_K, "ALIGN" },
113 { SECTIONS, "SECTIONS" },
114 { SIZEOF_HEADERS, "SIZEOF_HEADERS" },
115 { MEMORY, "MEMORY" },
116 { DEFINED, "DEFINED" },
117 { TARGET_K, "TARGET" },
118 { SEARCH_DIR, "SEARCH_DIR" },
122 { ALIGNOF, "ALIGNOF" },
123 { SIZEOF, "SIZEOF" },
125 { LOADADDR, "LOADADDR" },
126 { CONSTANT, "CONSTANT" },
127 { ABSOLUTE, "ABSOLUTE" },
130 { ASSERT_K, "ASSERT" },
131 { REL, "relocatable" },
132 { DATA_SEGMENT_ALIGN, "DATA_SEGMENT_ALIGN" },
133 { DATA_SEGMENT_RELRO_END, "DATA_SEGMENT_RELRO_END" },
134 { DATA_SEGMENT_END, "DATA_SEGMENT_END" },
135 { ORIGIN, "ORIGIN" },
136 { LENGTH, "LENGTH" },
137 { SEGMENT_START, "SEGMENT_START" }
141 for (idx = 0; idx < ARRAY_SIZE (table); idx++)
142 if (table[idx].code == code)
146 fputc (' ', config.map_file);
148 if (idx < ARRAY_SIZE (table))
149 fputs (table[idx].name, config.map_file);
151 fputc (code, config.map_file);
153 fprintf (config.map_file, "<code %d>", code);
156 fputc (' ', config.map_file);
162 bfd_vma value = expld.result.value;
164 bool round_up = false;
169 /* If more than one bit is set in the value we will need to round up. */
170 if ((value > 1) && (value & 1))
177 expld.result.section = NULL;
178 expld.result.value = result;
184 if (expld.result.section != NULL)
185 expld.result.value += expld.result.section->vma;
186 expld.result.section = bfd_abs_section_ptr;
187 expld.rel_from_abs = false;
191 new_abs (bfd_vma value)
193 expld.result.valid_p = true;
194 expld.result.section = bfd_abs_section_ptr;
195 expld.result.value = value;
196 expld.result.str = NULL;
200 exp_intop (bfd_vma value)
202 etree_type *new_e = stat_alloc (sizeof (new_e->value));
203 new_e->type.node_code = INT;
204 new_e->type.filename = ldlex_filename ();
205 new_e->type.lineno = lineno;
206 new_e->value.value = value;
207 new_e->value.str = NULL;
208 new_e->type.node_class = etree_value;
213 exp_bigintop (bfd_vma value, char *str)
215 etree_type *new_e = stat_alloc (sizeof (new_e->value));
216 new_e->type.node_code = INT;
217 new_e->type.filename = ldlex_filename ();
218 new_e->type.lineno = lineno;
219 new_e->value.value = value;
220 new_e->value.str = str;
221 new_e->type.node_class = etree_value;
225 /* Build an expression representing an unnamed relocatable value. */
228 exp_relop (asection *section, bfd_vma value)
230 etree_type *new_e = stat_alloc (sizeof (new_e->rel));
231 new_e->type.node_code = REL;
232 new_e->type.filename = ldlex_filename ();
233 new_e->type.lineno = lineno;
234 new_e->type.node_class = etree_rel;
235 new_e->rel.section = section;
236 new_e->rel.value = value;
241 new_number (bfd_vma value)
243 expld.result.valid_p = true;
244 expld.result.value = value;
245 expld.result.str = NULL;
246 expld.result.section = NULL;
250 new_rel (bfd_vma value, asection *section)
252 expld.result.valid_p = true;
253 expld.result.value = value;
254 expld.result.str = NULL;
255 expld.result.section = section;
259 new_rel_from_abs (bfd_vma value)
261 asection *s = expld.section;
263 expld.rel_from_abs = true;
264 expld.result.valid_p = true;
265 expld.result.value = value - s->vma;
266 expld.result.str = NULL;
267 expld.result.section = s;
270 /* New-function for the definedness hash table. */
272 static struct bfd_hash_entry *
273 definedness_newfunc (struct bfd_hash_entry *entry,
274 struct bfd_hash_table *table ATTRIBUTE_UNUSED,
275 const char *name ATTRIBUTE_UNUSED)
277 struct definedness_hash_entry *ret = (struct definedness_hash_entry *) entry;
280 ret = (struct definedness_hash_entry *)
281 bfd_hash_allocate (table, sizeof (struct definedness_hash_entry));
284 einfo (_("%F%P: bfd_hash_allocate failed creating symbol %s\n"), name);
291 /* Called during processing of linker script script expressions.
292 For symbols assigned in a linker script, return a struct describing
293 where the symbol is defined relative to the current expression,
294 otherwise return NULL. */
296 static struct definedness_hash_entry *
297 symbol_defined (const char *name)
299 return ((struct definedness_hash_entry *)
300 bfd_hash_lookup (&definedness_table, name, false, false));
303 /* Update the definedness state of NAME. Return FALSE if script symbol
304 is multiply defining a strong symbol in an object. */
307 update_definedness (const char *name, struct bfd_link_hash_entry *h)
310 struct definedness_hash_entry *defentry
311 = (struct definedness_hash_entry *)
312 bfd_hash_lookup (&definedness_table, name, true, false);
314 if (defentry == NULL)
315 einfo (_("%F%P: bfd_hash_lookup failed creating symbol %s\n"), name);
317 /* If the symbol was already defined, and not by a script, then it
318 must be defined by an object file or by the linker target code. */
321 && (h->type == bfd_link_hash_defined
322 || h->type == bfd_link_hash_defweak
323 || h->type == bfd_link_hash_common))
325 defentry->by_object = 1;
326 if (h->type == bfd_link_hash_defined
327 && h->u.def.section->output_section != NULL
328 && !bfd_is_abs_section (h->u.def.section)
333 defentry->iteration = lang_statement_iteration;
334 defentry->final_sec = bfd_abs_section_ptr;
335 if (expld.phase == lang_final_phase_enum
336 && expld.rel_from_abs
337 && expld.result.section == bfd_abs_section_ptr)
338 defentry->final_sec = section_for_dot ();
343 fold_segment_end (void)
345 seg_align_type *seg = &expld.dataseg;
347 if (expld.phase == lang_first_phase_enum
348 || expld.section != bfd_abs_section_ptr)
350 expld.result.valid_p = false;
352 else if (seg->phase == exp_seg_align_seen
353 || seg->phase == exp_seg_relro_seen)
355 seg->phase = exp_seg_end_seen;
356 seg->end = expld.result.value;
358 else if (seg->phase == exp_seg_done
359 || seg->phase == exp_seg_adjust
360 || seg->phase == exp_seg_relro_adjust)
365 expld.result.valid_p = false;
369 fold_unary (etree_type *tree)
371 exp_fold_tree_1 (tree->unary.child);
372 if (expld.result.valid_p)
374 switch (tree->type.node_code)
377 if (expld.phase != lang_first_phase_enum)
378 new_rel_from_abs (align_n (expld.dot, expld.result.value));
380 expld.result.valid_p = false;
392 expld.result.value = ~expld.result.value;
396 expld.result.value = !expld.result.value;
400 expld.result.value = -expld.result.value;
404 /* Return next place aligned to value. */
405 if (expld.phase != lang_first_phase_enum)
408 expld.result.value = align_n (expld.dot, expld.result.value);
411 expld.result.valid_p = false;
414 case DATA_SEGMENT_END:
425 /* Arithmetic operators, bitwise AND, bitwise OR and XOR keep the
426 section of one of their operands only when the other operand is a
427 plain number. Losing the section when operating on two symbols,
428 ie. a result of a plain number, is required for subtraction and
429 XOR. It's justifiable for the other operations on the grounds that
430 adding, multiplying etc. two section relative values does not
431 really make sense unless they are just treated as numbers.
432 The same argument could be made for many expressions involving one
433 symbol and a number. For example, "1 << x" and "100 / x" probably
434 should not be given the section of x. The trouble is that if we
435 fuss about such things the rules become complex and it is onerous
436 to document ld expression evaluation. */
438 arith_result_section (const etree_value_type *lhs)
440 if (expld.result.section == lhs->section)
442 if (expld.section == bfd_abs_section_ptr
443 && !config.sane_expr)
444 /* Duplicate the insanity in exp_fold_tree_1 case etree_value. */
445 expld.result.section = bfd_abs_section_ptr;
447 expld.result.section = NULL;
452 fold_segment_align (etree_value_type *lhs)
454 seg_align_type *seg = &expld.dataseg;
456 seg->relro = exp_seg_relro_start;
457 if (expld.phase == lang_first_phase_enum
458 || expld.section != bfd_abs_section_ptr)
459 expld.result.valid_p = false;
462 bfd_vma maxpage = lhs->value;
463 bfd_vma commonpage = expld.result.value;
465 expld.result.value = align_n (expld.dot, maxpage);
466 if (seg->phase == exp_seg_relro_adjust)
467 expld.result.value = seg->base;
468 else if (seg->phase == exp_seg_adjust)
470 if (commonpage < maxpage)
471 expld.result.value += ((expld.dot + commonpage - 1)
472 & (maxpage - commonpage));
476 if (!link_info.relro)
477 expld.result.value += expld.dot & (maxpage - 1);
478 if (seg->phase == exp_seg_done)
482 else if (seg->phase == exp_seg_none)
484 seg->phase = exp_seg_align_seen;
485 seg->base = expld.result.value;
486 seg->commonpagesize = commonpage;
487 seg->maxpagesize = maxpage;
488 seg->relropagesize = maxpage;
492 expld.result.valid_p = false;
498 fold_segment_relro_end (etree_value_type *lhs)
500 seg_align_type *seg = &expld.dataseg;
502 /* Operands swapped! XXX_SEGMENT_RELRO_END(offset,exp) has offset
503 in expld.result and exp in lhs. */
504 seg->relro = exp_seg_relro_end;
505 seg->relro_offset = expld.result.value;
506 if (expld.phase == lang_first_phase_enum
507 || expld.section != bfd_abs_section_ptr)
508 expld.result.valid_p = false;
509 else if (seg->phase == exp_seg_align_seen
510 || seg->phase == exp_seg_adjust
511 || seg->phase == exp_seg_relro_adjust
512 || seg->phase == exp_seg_done)
514 if (seg->phase == exp_seg_align_seen
515 || seg->phase == exp_seg_relro_adjust)
516 seg->relro_end = lhs->value + expld.result.value;
518 if (seg->phase == exp_seg_relro_adjust
519 && (seg->relro_end & (seg->relropagesize - 1)))
521 seg->relro_end += seg->relropagesize - 1;
522 seg->relro_end &= ~(seg->relropagesize - 1);
523 expld.result.value = seg->relro_end - expld.result.value;
526 expld.result.value = lhs->value;
528 if (seg->phase == exp_seg_align_seen)
529 seg->phase = exp_seg_relro_seen;
532 expld.result.valid_p = false;
536 fold_binary (etree_type *tree)
538 etree_value_type lhs;
539 exp_fold_tree_1 (tree->binary.lhs);
541 /* The SEGMENT_START operator is special because its first
542 operand is a string, not the name of a symbol. Note that the
543 operands have been swapped, so binary.lhs is second (default)
544 operand, binary.rhs is first operand. */
545 if (expld.result.valid_p && tree->type.node_code == SEGMENT_START)
547 bfd_vma value = expld.result.value;
548 const char *segment_name;
551 /* Check to see if the user has overridden the default
553 segment_name = tree->binary.rhs->name.name;
554 for (seg = segments; seg; seg = seg->next)
555 if (strcmp (seg->name, segment_name) == 0)
558 && config.magic_demand_paged
559 && link_info.maxpagesize != 0
560 && (seg->value % link_info.maxpagesize) != 0)
561 einfo (_("%P: warning: address of `%s' "
562 "isn't multiple of maximum page size\n"),
568 new_rel_from_abs (value);
573 exp_fold_tree_1 (tree->binary.rhs);
574 expld.result.valid_p &= lhs.valid_p;
576 if (expld.result.valid_p)
578 if (lhs.section != expld.result.section)
580 /* If the values are from different sections, and neither is
581 just a number, make both the source arguments absolute. */
582 if (expld.result.section != NULL
583 && lhs.section != NULL)
586 lhs.value += lhs.section->vma;
587 lhs.section = bfd_abs_section_ptr;
590 /* If the rhs is just a number, keep the lhs section. */
591 else if (expld.result.section == NULL)
593 expld.result.section = lhs.section;
594 /* Make this NULL so that we know one of the operands
595 was just a number, for later tests. */
599 /* At this point we know that both operands have the same
600 section, or at least one of them is a plain number. */
602 switch (tree->type.node_code)
606 expld.result.value = lhs.value y expld.result.value; \
607 arith_result_section (&lhs); \
610 /* Comparison operators, logical AND, and logical OR always
611 return a plain number. */
614 expld.result.value = lhs.value y expld.result.value; \
615 expld.result.section = NULL; \
636 if (expld.result.value != 0)
637 expld.result.value = ((bfd_signed_vma) lhs.value
638 % (bfd_signed_vma) expld.result.value);
639 else if (expld.phase != lang_mark_phase_enum)
640 einfo (_("%F%P:%pS %% by zero\n"), tree->binary.rhs);
641 arith_result_section (&lhs);
645 if (expld.result.value != 0)
646 expld.result.value = ((bfd_signed_vma) lhs.value
647 / (bfd_signed_vma) expld.result.value);
648 else if (expld.phase != lang_mark_phase_enum)
649 einfo (_("%F%P:%pS / by zero\n"), tree->binary.rhs);
650 arith_result_section (&lhs);
654 if (lhs.value > expld.result.value)
655 expld.result.value = lhs.value;
659 if (lhs.value < expld.result.value)
660 expld.result.value = lhs.value;
664 expld.result.value = align_n (lhs.value, expld.result.value);
667 case DATA_SEGMENT_ALIGN:
668 fold_segment_align (&lhs);
671 case DATA_SEGMENT_RELRO_END:
672 fold_segment_relro_end (&lhs);
682 fold_trinary (etree_type *tree)
684 struct bfd_link_hash_entry *save = expld.assign_src;
686 exp_fold_tree_1 (tree->trinary.cond);
687 expld.assign_src = save;
688 if (expld.result.valid_p)
689 exp_fold_tree_1 (expld.result.value
691 : tree->trinary.rhs);
695 fold_name (etree_type *tree)
697 struct bfd_link_hash_entry *h;
698 struct definedness_hash_entry *def;
700 memset (&expld.result, 0, sizeof (expld.result));
702 switch (tree->type.node_code)
705 link_info.load_phdrs = 1;
706 if (expld.phase != lang_first_phase_enum)
708 bfd_vma hdr_size = 0;
709 /* Don't find the real header size if only marking sections;
710 The bfd function may cache incorrect data. */
711 if (expld.phase != lang_mark_phase_enum)
712 hdr_size = (bfd_sizeof_headers (link_info.output_bfd, &link_info)
713 / bfd_octets_per_byte (link_info.output_bfd, NULL));
714 new_number (hdr_size);
719 h = bfd_wrapped_link_hash_lookup (link_info.output_bfd,
723 new_number (h != NULL
724 && (h->type == bfd_link_hash_defined
725 || h->type == bfd_link_hash_defweak
726 || h->type == bfd_link_hash_common)
728 || (def = symbol_defined (tree->name.name)) == NULL
730 || def->iteration == (lang_statement_iteration & 255)));
734 if (tree->name.name[0] == '.' && tree->name.name[1] == 0)
735 new_rel_from_abs (expld.dot);
738 h = bfd_wrapped_link_hash_lookup (link_info.output_bfd,
744 if (expld.phase != lang_first_phase_enum)
745 einfo (_("%F%P: bfd_link_hash_lookup failed: %E\n"));
747 else if (h->type == bfd_link_hash_defined
748 || h->type == bfd_link_hash_defweak)
750 asection *output_section;
752 output_section = h->u.def.section->output_section;
753 if (output_section == NULL)
755 if (expld.phase <= lang_mark_phase_enum)
756 new_rel (h->u.def.value, h->u.def.section);
758 einfo (_("%X%P:%pS: unresolvable symbol `%s'"
759 " referenced in expression\n"),
760 tree, tree->name.name);
762 else if (output_section == bfd_abs_section_ptr
763 && (expld.section != bfd_abs_section_ptr
764 || config.sane_expr))
765 new_number (h->u.def.value + h->u.def.section->output_offset);
767 new_rel (h->u.def.value + h->u.def.section->output_offset,
770 else if (expld.phase == lang_final_phase_enum
771 || (expld.phase != lang_mark_phase_enum
772 && expld.assigning_to_dot))
773 einfo (_("%F%P:%pS: undefined symbol `%s'"
774 " referenced in expression\n"),
775 tree, tree->name.name);
776 else if (h->type == bfd_link_hash_new)
778 h->type = bfd_link_hash_undefined;
779 h->u.undef.abfd = NULL;
780 if (h->u.undef.next == NULL && h != link_info.hash->undefs_tail)
781 bfd_link_add_undef (link_info.hash, h);
783 if (expld.assign_src == NULL)
784 expld.assign_src = h;
786 expld.assign_src = (struct bfd_link_hash_entry *) - 1;
788 /* Self-assignment is only allowed for absolute symbols
789 defined in a linker script. */
790 if (expld.assign_name != NULL
791 && strcmp (expld.assign_name, tree->name.name) == 0
793 && (h->type == bfd_link_hash_defined
794 || h->type == bfd_link_hash_defweak)
795 && h->u.def.section == bfd_abs_section_ptr
796 && (def = symbol_defined (tree->name.name)) != NULL
797 && def->iteration == (lang_statement_iteration & 255)))
798 expld.assign_name = NULL;
803 if (expld.phase != lang_first_phase_enum)
805 lang_output_section_statement_type *os;
807 os = lang_output_section_find (tree->name.name);
810 if (expld.phase == lang_final_phase_enum)
811 einfo (_("%F%P:%pS: undefined section `%s'"
812 " referenced in expression\n"),
813 tree, tree->name.name);
815 else if (os->processed_vma)
816 new_rel (0, os->bfd_section);
821 if (expld.phase != lang_first_phase_enum)
823 lang_output_section_statement_type *os;
825 os = lang_output_section_find (tree->name.name);
828 if (expld.phase == lang_final_phase_enum)
829 einfo (_("%F%P:%pS: undefined section `%s'"
830 " referenced in expression\n"),
831 tree, tree->name.name);
833 else if (os->processed_lma)
835 if (os->load_base == NULL)
836 new_abs (os->bfd_section->lma);
839 exp_fold_tree_1 (os->load_base);
840 if (expld.result.valid_p)
849 if (expld.phase != lang_first_phase_enum)
851 lang_output_section_statement_type *os;
853 os = lang_output_section_find (tree->name.name);
856 if (expld.phase == lang_final_phase_enum)
857 einfo (_("%F%P:%pS: undefined section `%s'"
858 " referenced in expression\n"),
859 tree, tree->name.name);
862 else if (os->bfd_section != NULL)
866 if (tree->type.node_code == SIZEOF)
868 if (os->processed_vma)
869 val = os->bfd_section->size;
871 /* If we've just called lang_reset_memory_regions,
872 size will be zero and a previous estimate of
873 size will be in rawsize. */
874 val = os->bfd_section->rawsize;
875 val /= bfd_octets_per_byte (link_info.output_bfd,
879 val = (bfd_vma)1 << os->bfd_section->alignment_power;
890 lang_memory_region_type *mem;
892 mem = lang_memory_region_lookup (tree->name.name, false);
894 new_number (mem->length);
896 einfo (_("%F%P:%pS: undefined MEMORY region `%s'"
897 " referenced in expression\n"),
898 tree, tree->name.name);
904 lang_memory_region_type *mem;
906 mem = lang_memory_region_lookup (tree->name.name, false);
908 new_rel_from_abs (mem->origin);
910 einfo (_("%F%P:%pS: undefined MEMORY region `%s'"
911 " referenced in expression\n"),
912 tree, tree->name.name);
917 if (strcmp (tree->name.name, "MAXPAGESIZE") == 0)
918 new_number (link_info.maxpagesize);
919 else if (strcmp (tree->name.name, "COMMONPAGESIZE") == 0)
920 new_number (link_info.commonpagesize);
922 einfo (_("%F%P:%pS: unknown constant `%s' referenced in expression\n"),
923 tree, tree->name.name);
932 /* Return true if TREE is '.'. */
935 is_dot (const etree_type *tree)
937 return (tree->type.node_class == etree_name
938 && tree->type.node_code == NAME
939 && tree->name.name[0] == '.'
940 && tree->name.name[1] == 0);
943 /* Return true if TREE is a constant equal to VAL. */
946 is_value (const etree_type *tree, bfd_vma val)
948 return (tree->type.node_class == etree_value
949 && tree->value.value == val);
952 /* Return true if TREE is an absolute symbol equal to VAL defined in
956 is_sym_value (const etree_type *tree, bfd_vma val)
958 struct bfd_link_hash_entry *h;
959 struct definedness_hash_entry *def;
961 return (tree->type.node_class == etree_name
962 && tree->type.node_code == NAME
963 && (def = symbol_defined (tree->name.name)) != NULL
964 && def->iteration == (lang_statement_iteration & 255)
965 && (h = bfd_wrapped_link_hash_lookup (link_info.output_bfd,
968 false, false, true)) != NULL
970 && h->type == bfd_link_hash_defined
971 && h->u.def.section == bfd_abs_section_ptr
972 && h->u.def.value == val);
975 /* Return true if TREE is ". != 0". */
978 is_dot_ne_0 (const etree_type *tree)
980 return (tree->type.node_class == etree_binary
981 && tree->type.node_code == NE
982 && is_dot (tree->binary.lhs)
983 && is_value (tree->binary.rhs, 0));
986 /* Return true if TREE is ". = . + 0" or ". = . + sym" where sym is an
987 absolute constant with value 0 defined in a linker script. */
990 is_dot_plus_0 (const etree_type *tree)
992 return (tree->type.node_class == etree_binary
993 && tree->type.node_code == '+'
994 && is_dot (tree->binary.lhs)
995 && (is_value (tree->binary.rhs, 0)
996 || is_sym_value (tree->binary.rhs, 0)));
999 /* Return true if TREE is "ALIGN (. != 0 ? some_expression : 1)". */
1002 is_align_conditional (const etree_type *tree)
1004 if (tree->type.node_class == etree_unary
1005 && tree->type.node_code == ALIGN_K)
1007 tree = tree->unary.child;
1008 return (tree->type.node_class == etree_trinary
1009 && is_dot_ne_0 (tree->trinary.cond)
1010 && is_value (tree->trinary.rhs, 1));
1016 exp_fold_tree_1 (etree_type *tree)
1020 memset (&expld.result, 0, sizeof (expld.result));
1024 switch (tree->type.node_class)
1027 if (expld.section == bfd_abs_section_ptr
1028 && !config.sane_expr)
1029 new_abs (tree->value.value);
1031 new_number (tree->value.value);
1032 expld.result.str = tree->value.str;
1036 if (expld.phase != lang_first_phase_enum)
1038 asection *output_section = tree->rel.section->output_section;
1039 new_rel (tree->rel.value + tree->rel.section->output_offset,
1043 memset (&expld.result, 0, sizeof (expld.result));
1047 exp_fold_tree_1 (tree->assert_s.child);
1048 if (expld.phase == lang_final_phase_enum && !expld.result.value)
1049 einfo ("%X%P: %s\n", tree->assert_s.message);
1061 fold_trinary (tree);
1066 case etree_provided:
1067 if (tree->assign.dst[0] == '.' && tree->assign.dst[1] == 0)
1069 if (tree->type.node_class != etree_assign)
1070 einfo (_("%F%P:%pS can not PROVIDE assignment to"
1071 " location counter\n"), tree);
1072 if (expld.phase != lang_first_phase_enum)
1074 /* Notify the folder that this is an assignment to dot. */
1075 expld.assigning_to_dot = true;
1076 exp_fold_tree_1 (tree->assign.src);
1077 expld.assigning_to_dot = false;
1079 /* If we are assigning to dot inside an output section
1080 arrange to keep the section, except for certain
1081 expressions that evaluate to zero. We ignore . = 0,
1082 . = . + 0, and . = ALIGN (. != 0 ? expr : 1).
1083 We can't ignore all expressions that evaluate to zero
1084 because an otherwise empty section might have padding
1085 added by an alignment expression that changes with
1086 relaxation. Such a section might have zero size
1087 before relaxation and so be stripped incorrectly. */
1088 if (expld.phase == lang_mark_phase_enum
1089 && expld.section != bfd_abs_section_ptr
1090 && expld.section != bfd_und_section_ptr
1091 && !(expld.result.valid_p
1092 && expld.result.value == 0
1093 && (is_value (tree->assign.src, 0)
1094 || is_sym_value (tree->assign.src, 0)
1095 || is_dot_plus_0 (tree->assign.src)
1096 || is_align_conditional (tree->assign.src))))
1097 expld.section->flags |= SEC_KEEP;
1099 if (!expld.result.valid_p
1100 || expld.section == bfd_und_section_ptr)
1102 if (expld.phase != lang_mark_phase_enum)
1103 einfo (_("%F%P:%pS invalid assignment to"
1104 " location counter\n"), tree);
1106 else if (expld.dotp == NULL)
1107 einfo (_("%F%P:%pS assignment to location counter"
1108 " invalid outside of SECTIONS\n"), tree);
1110 /* After allocation, assignment to dot should not be
1111 done inside an output section since allocation adds a
1112 padding statement that effectively duplicates the
1114 else if (expld.phase <= lang_allocating_phase_enum
1115 || expld.section == bfd_abs_section_ptr)
1119 nextdot = expld.result.value;
1120 if (expld.result.section != NULL)
1121 nextdot += expld.result.section->vma;
1123 nextdot += expld.section->vma;
1124 if (nextdot < expld.dot
1125 && expld.section != bfd_abs_section_ptr)
1126 einfo (_("%F%P:%pS cannot move location counter backwards"
1127 " (from %V to %V)\n"),
1128 tree, expld.dot, nextdot);
1131 expld.dot = nextdot;
1132 *expld.dotp = nextdot;
1137 memset (&expld.result, 0, sizeof (expld.result));
1141 struct bfd_link_hash_entry *h = NULL;
1143 if (tree->type.node_class == etree_provide)
1145 h = bfd_link_hash_lookup (link_info.hash, tree->assign.dst,
1146 false, false, true);
1148 || !(h->type == bfd_link_hash_new
1149 || h->type == bfd_link_hash_undefined
1150 || h->type == bfd_link_hash_undefweak
1153 /* Do nothing. The symbol was never referenced, or
1154 was defined in some object file. Note that
1155 undefweak symbols are defined by PROVIDE. This
1156 is to support glibc use of __rela_iplt_start and
1157 similar weak references. */
1162 expld.assign_name = tree->assign.dst;
1163 expld.assign_src = NULL;
1164 exp_fold_tree_1 (tree->assign.src);
1165 /* expld.assign_name remaining equal to tree->assign.dst
1166 below indicates the evaluation of tree->assign.src did
1167 not use the value of tree->assign.dst. We don't allow
1168 self assignment until the final phase for two reasons:
1169 1) Expressions are evaluated multiple times. With
1170 relaxation, the number of times may vary.
1171 2) Section relative symbol values cannot be correctly
1172 converted to absolute values, as is required by many
1173 expressions, until final section sizing is complete. */
1174 if (expld.phase == lang_final_phase_enum
1175 || expld.phase == lang_fixed_phase_enum
1176 || expld.assign_name != NULL)
1178 if (tree->type.node_class == etree_provide)
1179 tree->type.node_class = etree_provided;
1183 h = bfd_link_hash_lookup (link_info.hash, tree->assign.dst,
1186 einfo (_("%F%P:%s: hash creation failed\n"),
1190 /* If the expression is not valid then fake a zero value. In
1191 the final phase any errors will already have been raised,
1192 in earlier phases we want to create this definition so
1193 that it can be seen by other expressions. */
1194 if (!expld.result.valid_p
1195 && h->type == bfd_link_hash_new)
1197 expld.result.value = 0;
1198 expld.result.section = NULL;
1199 expld.result.valid_p = true;
1202 if (expld.result.valid_p)
1204 if (expld.result.section == NULL)
1205 expld.result.section = expld.section;
1206 if (!update_definedness (tree->assign.dst, h)
1207 && expld.assign_name != NULL)
1209 /* Symbol was already defined, and the script isn't
1210 modifying the symbol value for some reason as in
1211 ld-elf/var1 and ld-scripts/pr14962.
1212 For now this is only a warning. */
1213 unsigned int warn = link_info.warn_multiple_definition;
1214 link_info.warn_multiple_definition = 1;
1215 (*link_info.callbacks->multiple_definition)
1216 (&link_info, h, link_info.output_bfd,
1217 expld.result.section, expld.result.value);
1218 link_info.warn_multiple_definition = warn;
1220 if (expld.phase == lang_fixed_phase_enum)
1222 if (h->type == bfd_link_hash_defined)
1224 expld.result.value = h->u.def.value;
1225 expld.result.section = h->u.def.section;
1230 h->type = bfd_link_hash_defined;
1231 h->u.def.value = expld.result.value;
1232 h->u.def.section = expld.result.section;
1233 h->linker_def = ! tree->assign.type.lineno;
1234 h->ldscript_def = 1;
1235 h->rel_from_abs = expld.rel_from_abs;
1236 if (tree->assign.hidden)
1237 bfd_link_hide_symbol (link_info.output_bfd,
1240 /* Copy the symbol type and set non_ir_ref_regular
1241 on the source if this is an expression only
1242 referencing a single symbol. (If the expression
1243 contains ternary conditions, ignoring symbols on
1245 if (expld.assign_src != NULL
1246 && (expld.assign_src
1247 != (struct bfd_link_hash_entry *) -1))
1249 bfd_copy_link_hash_symbol_type (link_info.output_bfd,
1250 h, expld.assign_src);
1251 expld.assign_src->non_ir_ref_regular = true;
1256 if (expld.phase != lang_fixed_phase_enum)
1257 expld.assign_name = NULL;
1267 memset (&expld.result, 0, sizeof (expld.result));
1273 exp_fold_tree (etree_type *tree, asection *current_section, bfd_vma *dotp)
1275 expld.rel_from_abs = false;
1278 expld.section = current_section;
1279 exp_fold_tree_1 (tree);
1283 exp_fold_tree_no_dot (etree_type *tree)
1285 expld.rel_from_abs = false;
1288 expld.section = bfd_abs_section_ptr;
1289 exp_fold_tree_1 (tree);
1293 exp_value_fold (etree_type *tree)
1295 exp_fold_tree_no_dot (tree);
1296 if (expld.result.valid_p)
1298 tree->type.node_code = INT;
1299 tree->value.value = expld.result.value;
1300 tree->value.str = NULL;
1301 tree->type.node_class = etree_value;
1305 #define MAX(a, b) ((a) > (b) ? (a) : (b))
1308 exp_binop (int code, etree_type *lhs, etree_type *rhs)
1310 etree_type *new_e = stat_alloc (MAX (sizeof (new_e->binary),
1311 sizeof (new_e->value)));
1312 new_e->type.node_code = code;
1313 new_e->type.filename = lhs->type.filename;
1314 new_e->type.lineno = lhs->type.lineno;
1315 new_e->binary.lhs = lhs;
1316 new_e->binary.rhs = rhs;
1317 new_e->type.node_class = etree_binary;
1318 if (lhs->type.node_class == etree_value
1319 && rhs->type.node_class == etree_value
1321 && code != DATA_SEGMENT_ALIGN
1322 && code != DATA_SEGMENT_RELRO_END)
1323 exp_value_fold (new_e);
1328 exp_trinop (int code, etree_type *cond, etree_type *lhs, etree_type *rhs)
1330 etree_type *new_e = stat_alloc (MAX (sizeof (new_e->trinary),
1331 sizeof (new_e->value)));
1332 new_e->type.node_code = code;
1333 new_e->type.filename = cond->type.filename;
1334 new_e->type.lineno = cond->type.lineno;
1335 new_e->trinary.lhs = lhs;
1336 new_e->trinary.cond = cond;
1337 new_e->trinary.rhs = rhs;
1338 new_e->type.node_class = etree_trinary;
1339 if (cond->type.node_class == etree_value
1340 && lhs->type.node_class == etree_value
1341 && rhs->type.node_class == etree_value)
1342 exp_value_fold (new_e);
1347 exp_unop (int code, etree_type *child)
1349 etree_type *new_e = stat_alloc (MAX (sizeof (new_e->unary),
1350 sizeof (new_e->value)));
1351 new_e->unary.type.node_code = code;
1352 new_e->unary.type.filename = child->type.filename;
1353 new_e->unary.type.lineno = child->type.lineno;
1354 new_e->unary.child = child;
1355 new_e->unary.type.node_class = etree_unary;
1356 if (child->type.node_class == etree_value
1360 && code != DATA_SEGMENT_END)
1361 exp_value_fold (new_e);
1366 exp_nameop (int code, const char *name)
1368 etree_type *new_e = stat_alloc (sizeof (new_e->name));
1370 new_e->name.type.node_code = code;
1371 new_e->name.type.filename = ldlex_filename ();
1372 new_e->name.type.lineno = lineno;
1373 new_e->name.name = name;
1374 new_e->name.type.node_class = etree_name;
1380 exp_assop (const char *dst,
1382 enum node_tree_enum class,
1387 n = stat_alloc (sizeof (n->assign));
1388 n->assign.type.node_code = '=';
1389 n->assign.type.filename = src->type.filename;
1390 n->assign.type.lineno = src->type.lineno;
1391 n->assign.type.node_class = class;
1392 n->assign.src = src;
1393 n->assign.dst = dst;
1394 n->assign.hidden = hidden;
1398 /* Handle linker script assignments and HIDDEN. */
1401 exp_assign (const char *dst, etree_type *src, bool hidden)
1403 return exp_assop (dst, src, etree_assign, hidden);
1406 /* Handle --defsym command-line option. */
1409 exp_defsym (const char *dst, etree_type *src)
1411 return exp_assop (dst, src, etree_assign, false);
1414 /* Handle PROVIDE. */
1417 exp_provide (const char *dst, etree_type *src, bool hidden)
1419 return exp_assop (dst, src, etree_provide, hidden);
1422 /* Handle ASSERT. */
1425 exp_assert (etree_type *exp, const char *message)
1429 n = stat_alloc (sizeof (n->assert_s));
1430 n->assert_s.type.node_code = '!';
1431 n->assert_s.type.filename = exp->type.filename;
1432 n->assert_s.type.lineno = exp->type.lineno;
1433 n->assert_s.type.node_class = etree_assert;
1434 n->assert_s.child = exp;
1435 n->assert_s.message = message;
1440 exp_print_tree (etree_type *tree)
1444 if (config.map_file == NULL)
1445 config.map_file = stderr;
1449 minfo ("NULL TREE\n");
1453 switch (tree->type.node_class)
1456 minfo ("0x%v", tree->value.value);
1459 if (tree->rel.section->owner != NULL)
1460 minfo ("%pB:", tree->rel.section->owner);
1461 minfo ("%s+0x%v", tree->rel.section->name, tree->rel.value);
1464 fputs (tree->assign.dst, config.map_file);
1465 exp_print_token (tree->type.node_code, true);
1466 exp_print_tree (tree->assign.src);
1469 case etree_provided:
1470 fprintf (config.map_file, "PROVIDE (%s = ", tree->assign.dst);
1471 exp_print_tree (tree->assign.src);
1472 fputc (')', config.map_file);
1475 function_like = false;
1476 switch (tree->type.node_code)
1481 case DATA_SEGMENT_ALIGN:
1482 case DATA_SEGMENT_RELRO_END:
1483 function_like = true;
1486 /* Special handling because arguments are in reverse order and
1487 the segment name is quoted. */
1488 exp_print_token (tree->type.node_code, false);
1489 fputs (" (\"", config.map_file);
1490 exp_print_tree (tree->binary.rhs);
1491 fputs ("\", ", config.map_file);
1492 exp_print_tree (tree->binary.lhs);
1493 fputc (')', config.map_file);
1498 exp_print_token (tree->type.node_code, false);
1499 fputc (' ', config.map_file);
1501 fputc ('(', config.map_file);
1502 exp_print_tree (tree->binary.lhs);
1504 fprintf (config.map_file, ", ");
1506 exp_print_token (tree->type.node_code, true);
1507 exp_print_tree (tree->binary.rhs);
1508 fputc (')', config.map_file);
1511 exp_print_tree (tree->trinary.cond);
1512 fputc ('?', config.map_file);
1513 exp_print_tree (tree->trinary.lhs);
1514 fputc (':', config.map_file);
1515 exp_print_tree (tree->trinary.rhs);
1518 exp_print_token (tree->unary.type.node_code, false);
1519 if (tree->unary.child)
1521 fprintf (config.map_file, " (");
1522 exp_print_tree (tree->unary.child);
1523 fputc (')', config.map_file);
1528 fprintf (config.map_file, "ASSERT (");
1529 exp_print_tree (tree->assert_s.child);
1530 fprintf (config.map_file, ", %s)", tree->assert_s.message);
1534 if (tree->type.node_code == NAME)
1535 fputs (tree->name.name, config.map_file);
1538 exp_print_token (tree->type.node_code, false);
1539 if (tree->name.name)
1540 fprintf (config.map_file, " (%s)", tree->name.name);
1550 exp_get_vma (etree_type *tree, bfd_vma def, char *name)
1554 exp_fold_tree_no_dot (tree);
1555 if (expld.result.valid_p)
1556 return expld.result.value;
1557 else if (name != NULL && expld.phase != lang_mark_phase_enum)
1558 einfo (_("%F%P:%pS: nonconstant expression for %s\n"),
1564 /* Return the smallest non-negative integer such that two raised to
1565 that power is at least as large as the vma evaluated at TREE, if
1566 TREE is a non-NULL expression that can be resolved. If TREE is
1567 NULL or cannot be resolved, return -1. */
1570 exp_get_power (etree_type *tree, char *name)
1572 bfd_vma x = exp_get_vma (tree, -1, name);
1576 if (x == (bfd_vma) -1)
1579 for (n = 0, p2 = 1; p2 < x; ++n, p2 <<= 1)
1587 exp_get_fill (etree_type *tree, fill_type *def, char *name)
1596 exp_fold_tree_no_dot (tree);
1597 if (!expld.result.valid_p)
1599 if (name != NULL && expld.phase != lang_mark_phase_enum)
1600 einfo (_("%F%P:%pS: nonconstant expression for %s\n"),
1605 if (expld.result.str != NULL && (len = strlen (expld.result.str)) != 0)
1609 fill = (fill_type *) xmalloc ((len + 1) / 2 + sizeof (*fill) - 1);
1610 fill->size = (len + 1) / 2;
1612 s = (unsigned char *) expld.result.str;
1620 digit = (digit - 'A' + '0' + 10) & 0xf;
1634 fill = (fill_type *) xmalloc (4 + sizeof (*fill) - 1);
1635 val = expld.result.value;
1636 fill->data[0] = (val >> 24) & 0xff;
1637 fill->data[1] = (val >> 16) & 0xff;
1638 fill->data[2] = (val >> 8) & 0xff;
1639 fill->data[3] = (val >> 0) & 0xff;
1646 exp_get_abs_int (etree_type *tree, int def, char *name)
1650 exp_fold_tree_no_dot (tree);
1652 if (expld.result.valid_p)
1654 if (expld.result.section != NULL)
1655 expld.result.value += expld.result.section->vma;
1656 return expld.result.value;
1658 else if (name != NULL && expld.phase != lang_mark_phase_enum)
1660 einfo (_("%F%P:%pS: nonconstant expression for %s\n"),
1668 align_n (bfd_vma value, bfd_vma align)
1673 value = (value + align - 1) / align;
1674 return value * align;
1680 /* The value "13" is ad-hoc, somewhat related to the expected number of
1681 assignments in a linker script. */
1682 if (!bfd_hash_table_init_n (&definedness_table,
1683 definedness_newfunc,
1684 sizeof (struct definedness_hash_entry),
1686 einfo (_("%F%P: can not create hash table: %E\n"));
1689 /* Convert absolute symbols defined by a script from "dot" (also
1690 SEGMENT_START or ORIGIN) outside of an output section statement,
1691 to section relative. */
1694 set_sym_sections (struct bfd_hash_entry *bh, void *inf ATTRIBUTE_UNUSED)
1696 struct definedness_hash_entry *def = (struct definedness_hash_entry *) bh;
1697 if (def->final_sec != bfd_abs_section_ptr)
1699 struct bfd_link_hash_entry *h;
1700 h = bfd_link_hash_lookup (link_info.hash, bh->string,
1701 false, false, true);
1703 && h->type == bfd_link_hash_defined
1704 && h->u.def.section == bfd_abs_section_ptr)
1706 h->u.def.value -= def->final_sec->vma;
1707 h->u.def.section = def->final_sec;
1714 ldexp_finalize_syms (void)
1716 bfd_hash_traverse (&definedness_table, set_sym_sections, NULL);
1719 /* Determine whether a symbol is going to remain absolute even after
1720 ldexp_finalize_syms() has run. */
1723 ldexp_is_final_sym_absolute (const struct bfd_link_hash_entry *h)
1725 if (h->type == bfd_link_hash_defined
1726 && h->u.def.section == bfd_abs_section_ptr)
1728 const struct definedness_hash_entry *def;
1730 if (!h->ldscript_def)
1733 def = symbol_defined (h->root.string);
1735 return def->final_sec == bfd_abs_section_ptr;
1744 bfd_hash_table_free (&definedness_table);