Allow self-assignment for absolute symbols defined in a linker script
Modifies ld machinery tracking linker script assignments to notice all assignments, not just those symbols mentioned in DEFINED(). ld/ PR ld/14962 * ldlang.h (struct lang_definedness_hash_entry): Add by_object and by_script. Make iteration a single bit field. (lang_track_definedness, lang_symbol_definition_iteration): Delete. (lang_symbol_defined): Declare. * ldlang.c (lang_statement_iteration): Expand comment a little. (lang_init <lang_definedness_table>): Make it bigger. (lang_track_definedness, lang_symbol_definition): Delete. (lang_definedness_newfunc): Update. (lang_symbol_defined): New function. (lang_update_definedness): Create entries here. Do track whether script definition of symbol is valid, even when also defined in an object file. * ldexp.c (fold_name <DEFINED>): Update. (fold_name <NAME>): Allow self-assignment for absolute symbols defined in a linker script. ld/testsuite/ * ld-scripts/pr14962-2.d, * ld-scripts/pr14962-2.t: New test. * ld-scripts/expr.exp: Run it.
This commit is contained in:
Alan Modra
parent
24ef1aa73e
commit
fa72205cb9
8 changed files with 98 additions and 60 deletions
18
ld/ChangeLog
18
ld/ChangeLog
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@ -1,3 +1,21 @@
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2014-01-20 Alan Modra <amodra@gmail.com>
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* ldlang.h (struct lang_definedness_hash_entry): Add by_object and
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by_script. Make iteration a single bit field.
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(lang_track_definedness, lang_symbol_definition_iteration): Delete.
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(lang_symbol_defined): Declare.
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* ldlang.c (lang_statement_iteration): Expand comment a little.
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(lang_init <lang_definedness_table>): Make it bigger.
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(lang_track_definedness, lang_symbol_definition): Delete.
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(lang_definedness_newfunc): Update.
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(lang_symbol_defined): New function.
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(lang_update_definedness): Create entries here. Do track whether
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script definition of symbol is valid, even when also defined in
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an object file.
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* ldexp.c (fold_name <DEFINED>): Update.
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(fold_name <NAME>): Allow self-assignment for absolute symbols
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defined in a linker script.
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2014-01-20 Guy Martin <gmsoft@tuxicoman.be>
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Alan Modra <amodra@gmail.com>
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31
ld/ldexp.c
31
ld/ldexp.c
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@ -575,13 +575,10 @@ fold_name (etree_type *tree)
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break;
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case DEFINED:
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if (expld.phase == lang_first_phase_enum)
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lang_track_definedness (tree->name.name);
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else
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if (expld.phase != lang_first_phase_enum)
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{
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struct bfd_link_hash_entry *h;
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int def_iteration
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= lang_symbol_definition_iteration (tree->name.name);
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struct lang_definedness_hash_entry *def;
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h = bfd_wrapped_link_hash_lookup (link_info.output_bfd,
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&link_info,
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@ -591,15 +588,33 @@ fold_name (etree_type *tree)
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&& (h->type == bfd_link_hash_defined
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|| h->type == bfd_link_hash_defweak
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|| h->type == bfd_link_hash_common)
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&& (def_iteration == lang_statement_iteration
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|| def_iteration == -1));
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&& ((def = lang_symbol_defined (tree->name.name)) == NULL
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|| def->by_object
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|| def->iteration == (lang_statement_iteration & 1)));
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}
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break;
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case NAME:
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if (expld.assign_name != NULL
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&& strcmp (expld.assign_name, tree->name.name) == 0)
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expld.assign_name = NULL;
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{
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/* Self-assignment is only allowed for absolute symbols
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defined in a linker script. */
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struct bfd_link_hash_entry *h;
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struct lang_definedness_hash_entry *def;
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h = bfd_wrapped_link_hash_lookup (link_info.output_bfd,
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&link_info,
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tree->name.name,
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FALSE, FALSE, TRUE);
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if (!(h != NULL
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&& (h->type == bfd_link_hash_defined
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|| h->type == bfd_link_hash_defweak)
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&& h->u.def.section == bfd_abs_section_ptr
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&& (def = lang_symbol_defined (tree->name.name)) != NULL
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&& def->iteration == (lang_statement_iteration & 1)))
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expld.assign_name = NULL;
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}
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if (expld.phase == lang_first_phase_enum)
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;
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else if (tree->name.name[0] == '.' && tree->name.name[1] == 0)
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74
ld/ldlang.c
74
ld/ldlang.c
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@ -107,7 +107,7 @@ struct lang_phdr *lang_phdr_list;
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struct lang_nocrossrefs *nocrossref_list;
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/* Functions that traverse the linker script and might evaluate
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DEFINED() need to increment this. */
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DEFINED() need to increment this at the start of the traversal. */
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int lang_statement_iteration = 0;
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etree_type *base; /* Relocation base - or null */
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@ -1221,16 +1221,12 @@ lang_init (void)
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abs_output_section->bfd_section = bfd_abs_section_ptr;
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/* The value "3" is ad-hoc, somewhat related to the expected number of
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DEFINED expressions in a linker script. For most default linker
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scripts, there are none. Why a hash table then? Well, it's somewhat
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simpler to re-use working machinery than using a linked list in terms
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of code-complexity here in ld, besides the initialization which just
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looks like other code here. */
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/* The value "13" is ad-hoc, somewhat related to the expected number of
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assignments in a linker script. */
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if (!bfd_hash_table_init_n (&lang_definedness_table,
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lang_definedness_newfunc,
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sizeof (struct lang_definedness_hash_entry),
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3))
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13))
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einfo (_("%P%F: can not create hash table: %E\n"));
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}
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@ -2054,7 +2050,7 @@ lang_map (void)
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obstack_begin (&map_obstack, 1000);
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bfd_link_hash_traverse (link_info.hash, sort_def_symbol, 0);
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}
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lang_statement_iteration ++;
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lang_statement_iteration++;
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print_statements ();
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}
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@ -3286,15 +3282,6 @@ open_input_bfds (lang_statement_union_type *s, enum open_bfd_mode mode)
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einfo ("%F");
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}
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/* Add a symbol to a hash of symbols used in DEFINED (NAME) expressions. */
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void
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lang_track_definedness (const char *name)
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{
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if (bfd_hash_lookup (&lang_definedness_table, name, TRUE, FALSE) == NULL)
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einfo (_("%P%F: bfd_hash_lookup failed creating symbol %s\n"), name);
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}
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/* New-function for the definedness hash table. */
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static struct bfd_hash_entry *
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@ -3312,28 +3299,22 @@ lang_definedness_newfunc (struct bfd_hash_entry *entry,
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if (ret == NULL)
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einfo (_("%P%F: bfd_hash_allocate failed creating symbol %s\n"), name);
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ret->iteration = -1;
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ret->by_object = 0;
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ret->by_script = 0;
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ret->iteration = 0;
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return &ret->root;
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}
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/* Return the iteration when the definition of NAME was last updated. A
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value of -1 means that the symbol is not defined in the linker script
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or the command line, but may be defined in the linker symbol table. */
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/* Called during processing of linker script script expressions.
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For symbols assigned in a linker script, return a struct describing
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where the symbol is defined relative to the current expression,
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otherwise return NULL. */
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int
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lang_symbol_definition_iteration (const char *name)
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struct lang_definedness_hash_entry *
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lang_symbol_defined (const char *name)
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{
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struct lang_definedness_hash_entry *defentry
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= (struct lang_definedness_hash_entry *)
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bfd_hash_lookup (&lang_definedness_table, name, FALSE, FALSE);
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/* We've already created this one on the presence of DEFINED in the
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script, so it can't be NULL unless something is borked elsewhere in
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the code. */
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if (defentry == NULL)
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FAIL ();
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return defentry->iteration;
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return ((struct lang_definedness_hash_entry *)
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bfd_hash_lookup (&lang_definedness_table, name, FALSE, FALSE));
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}
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/* Update the definedness state of NAME. */
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@ -3343,25 +3324,20 @@ lang_update_definedness (const char *name, struct bfd_link_hash_entry *h)
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{
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struct lang_definedness_hash_entry *defentry
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= (struct lang_definedness_hash_entry *)
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bfd_hash_lookup (&lang_definedness_table, name, FALSE, FALSE);
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bfd_hash_lookup (&lang_definedness_table, name, TRUE, FALSE);
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/* We don't keep track of symbols not tested with DEFINED. */
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if (defentry == NULL)
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return;
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einfo (_("%P%F: bfd_hash_lookup failed creating symbol %s\n"), name);
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/* If the symbol was already defined, and not from an earlier statement
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iteration, don't update the definedness iteration, because that'd
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make the symbol seem defined in the linker script at this point, and
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it wasn't; it was defined in some object. If we do anyway, DEFINED
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would start to yield false before this point and the construct "sym =
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DEFINED (sym) ? sym : X;" would change sym to X despite being defined
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in an object. */
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if (h->type != bfd_link_hash_undefined
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/* If the symbol was already defined, and not by a script, then it
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must be defined by an object file. */
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if (!defentry->by_script
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&& h->type != bfd_link_hash_undefined
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&& h->type != bfd_link_hash_common
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&& h->type != bfd_link_hash_new
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&& defentry->iteration == -1)
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return;
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&& h->type != bfd_link_hash_new)
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defentry->by_object = 1;
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defentry->by_script = 1;
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defentry->iteration = lang_statement_iteration;
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}
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@ -465,7 +465,9 @@ struct unique_sections
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struct lang_definedness_hash_entry
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{
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struct bfd_hash_entry root;
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int iteration;
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unsigned int by_object : 1;
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unsigned int by_script : 1;
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unsigned int iteration : 1;
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};
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/* Used by place_orphan to keep track of orphan sections and statements. */
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@ -658,8 +660,7 @@ extern void lang_add_unique
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(const char *);
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extern const char *lang_get_output_target
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(void);
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extern void lang_track_definedness (const char *);
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extern int lang_symbol_definition_iteration (const char *);
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extern struct lang_definedness_hash_entry *lang_symbol_defined (const char *);
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extern void lang_update_definedness
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(const char *, struct bfd_link_hash_entry *);
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@ -1,3 +1,9 @@
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2014-01-20 Alan Modra <amodra@gmail.com>
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* ld-scripts/pr14962-2.d,
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* ld-scripts/pr14962-2.t: New test.
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* ld-scripts/expr.exp: Run it.
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2014-01-15 Alan Modra <amodra@gmail.com>
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* ld-elf/ehdr_start-shared.d: New.
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@ -25,3 +25,4 @@ run_dump_test expr2
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run_dump_test sane1
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run_dump_test assign-loc
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run_dump_test pr14962
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run_dump_test pr14962-2
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10
ld/testsuite/ld-scripts/pr14962-2.d
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10
ld/testsuite/ld-scripts/pr14962-2.d
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@ -0,0 +1,10 @@
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#ld: -T pr14962-2.t
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#source: pr14962a.s
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#nm: -n
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#notarget: rx-*-* frv-linux
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#...
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0+2000 [AT] _start
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#...
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0+2000 A x
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#pass
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11
ld/testsuite/ld-scripts/pr14962-2.t
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11
ld/testsuite/ld-scripts/pr14962-2.t
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@ -0,0 +1,11 @@
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TOTO = 4096;
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TOTO += 4096;
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SECTIONS
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{
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.text TOTO :
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{
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x = ABSOLUTE(TOTO);
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*(*.text)
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}
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}
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