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Warn when a script redefines a symbol

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Note that we don't even warn if scripts adjust a symbol as in
ld-elf/var1 and ld-scripts/pr14962.

include/
	* bfdlink.h (struct bfd_link_info): Add warn_multiple_definition.
ld/
	* ldexp.c (exp_fold_tree_1): Warn on script defining a symbol
	defined in an object file.
	* ldmain.c (multiple_definition): Heed info->warn_multiple_definition.
	* testsuite/ld-scripts/defined5.d: Expect a warning.
This commit is contained in:
Alan Modra 2021-02-20 15:45:44 +10:30
parent 93993f6784
commit 89753bbf81
6 changed files with 32 additions and 11 deletions
Download patch file Download diff file Expand all files Collapse all files

4
include/ChangeLog
View file

@ -1,3 +1,7 @@
2021-02-21 Alan Modra <amodra@gmail.com>
* bfdlink.h (struct bfd_link_info): Add warn_multiple_definition.
2021-02-17 Nick Alcock <nick.alcock@oracle.com> 2021-02-17 Nick Alcock <nick.alcock@oracle.com>
* ctf-api.h (ctf_arc_lookup_symbol_name): New. * ctf-api.h (ctf_arc_lookup_symbol_name): New.

8
include/bfdlink.h
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@ -465,12 +465,16 @@ struct bfd_link_info
statics. */ statics. */
unsigned int task_link: 1; unsigned int task_link: 1;
/* TRUE if ok to have multiple definition. */ /* TRUE if ok to have multiple definitions, without warning. */
unsigned int allow_multiple_definition: 1; unsigned int allow_multiple_definition: 1;
/* TRUE if ok to have prohibit multiple definition of absolute symbols. */ /* TRUE if multiple definition of absolute symbols (eg. from -R) should
be reported. */
unsigned int prohibit_multiple_definition_absolute: 1; unsigned int prohibit_multiple_definition_absolute: 1;
/* TRUE if multiple definitions should only warn. */
unsigned int warn_multiple_definition: 1;
/* TRUE if ok to have version with no definition. */ /* TRUE if ok to have version with no definition. */
unsigned int allow_undefined_version: 1; unsigned int allow_undefined_version: 1;

7
ld/ChangeLog
View file

@ -1,3 +1,10 @@
2021-02-21 Alan Modra <amodra@gmail.com>
* ldexp.c (exp_fold_tree_1): Warn on script defining a symbol
defined in an object file.
* ldmain.c (multiple_definition): Heed info->warn_multiple_definition.
* testsuite/ld-scripts/defined5.d: Expect a warning.
2021-02-19 Alan Modra <amodra@gmail.com> 2021-02-19 Alan Modra <amodra@gmail.com>
* testsuite/lib/ld-lib.exp: Whitespace. * testsuite/lib/ld-lib.exp: Whitespace.

15
ld/ldexp.c
View file

@ -1186,16 +1186,19 @@ exp_fold_tree_1 (etree_type *tree)
{ {
if (expld.result.section == NULL) if (expld.result.section == NULL)
expld.result.section = expld.section; expld.result.section = expld.section;
if (!update_definedness (tree->assign.dst, h) && 0) if (!update_definedness (tree->assign.dst, h)
&& expld.assign_name != NULL)
{ {
/* Symbol was already defined. For now this error /* Symbol was already defined, and the script isn't
is disabled because it causes failures in the ld modifying the symbol value for some reason as in
testsuite: ld-elf/var1, ld-scripts/defined5, and ld-elf/var1 and ld-scripts/pr14962.
ld-scripts/pr14962. Some of these no doubt For now this is only a warning. */
reflect scripts used in the wild. */ unsigned int warn = link_info.warn_multiple_definition;
link_info.warn_multiple_definition = 1;
(*link_info.callbacks->multiple_definition) (*link_info.callbacks->multiple_definition)
(&link_info, h, link_info.output_bfd, (&link_info, h, link_info.output_bfd,
expld.result.section, expld.result.value); expld.result.section, expld.result.value);
link_info.warn_multiple_definition = warn;
} }
if (expld.phase == lang_fixed_phase_enum) if (expld.phase == lang_fixed_phase_enum)
{ {

4
ld/ldmain.c
View file

@ -1074,7 +1074,9 @@ multiple_definition (struct bfd_link_info *info,
nval = oval; nval = oval;
obfd = NULL; obfd = NULL;
} }
einfo (_("%X%P: %C: multiple definition of `%pT'"), if (!info->warn_multiple_definition)
einfo ("%X");
einfo (_("%P: %C: multiple definition of `%pT'"),
nbfd, nsec, nval, name); nbfd, nsec, nval, name);
if (obfd != NULL) if (obfd != NULL)
einfo (_("; %D: first defined here"), obfd, osec, oval); einfo (_("; %D: first defined here"), obfd, osec, oval);

5
ld/testsuite/ld-scripts/defined5.d
View file

@ -1,10 +1,11 @@
#ld: -Tdefined5.t #ld: -Tdefined5.t
#warning: .*multiple definition of `defined'.*
#nm: -B #nm: -B
#source: defined5.s
#xfail: [is_xcoff_format] #xfail: [is_xcoff_format]
# xcoff outputs value of "defined" from the object file # xcoff outputs value of "defined" from the object file
# Check that arithmetic on DEFINED works. # Check that a script can override an object file symbol, if multiple
# definitions are allowed. See pr12356.
#... #...
0+1000 D defined 0+1000 D defined
#pass #pass