From 97196564c7e981bab7b968e19b171c5dfcb28c3c Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Fri, 6 May 2016 09:46:34 -0700 Subject: Strip global symbol defined in discarded section When a global symbol is defined in COMDAT group, we shouldn't leave an undefined symbol in symbol table when the symbol section is discarded unless there is a reference to the symbol outside of COMDAT group. bfd/ PR ld/17550 * elf-bfd.h (elf_link_hash_entry): Update comments for indx, documenting that indx == -3 if symbol is defined in a discarded section. * elflink.c (elf_link_add_object_symbols): Set indx to -3 if symbol is defined in a discarded section. (elf_link_output_extsym): Strip a global symbol defined in a discarded section. ld/ PR ld/17550 * testsuite/ld-elf/pr17550-1.s: New file. * testsuite/ld-elf/pr17550-2.s: Likewise. * testsuite/ld-elf/pr17550-3.s: Likewise. * testsuite/ld-elf/pr17550-4.s: Likewise. * testsuite/ld-elf/pr17550a.d: Likewise. * testsuite/ld-elf/pr17550b.d: Likewise. * testsuite/ld-elf/pr17550c.d: Likewise. * testsuite/ld-elf/pr17550d.d: Likewise. --- bfd/ChangeLog | 11 +++++++++++ bfd/elf-bfd.h | 3 ++- bfd/elflink.c | 12 ++++++++++++ 3 files changed, 25 insertions(+), 1 deletion(-) (limited to 'bfd') diff --git a/bfd/ChangeLog b/bfd/ChangeLog index c6a51c4..dfd9c1b 100644 --- a/bfd/ChangeLog +++ b/bfd/ChangeLog @@ -1,5 +1,16 @@ 2016-05-06 H.J. Lu + PR ld/17550 + * elf-bfd.h (elf_link_hash_entry): Update comments for indx, + documenting that indx == -3 if symbol is defined in a discarded + section. + * elflink.c (elf_link_add_object_symbols): Set indx to -3 if + symbol is defined in a discarded section. + (elf_link_output_extsym): Strip a global symbol defined in a + discarded section. + +2016-05-06 H.J. Lu + * elf32-i386.c (elf_backend_add_symbol_hook): Defined for Intel MCU. diff --git a/bfd/elf-bfd.h b/bfd/elf-bfd.h index 9067dd9..863fc39 100644 --- a/bfd/elf-bfd.h +++ b/bfd/elf-bfd.h @@ -124,7 +124,8 @@ struct elf_link_hash_entry struct bfd_link_hash_entry root; /* Symbol index in output file. This is initialized to -1. It is - set to -2 if the symbol is used by a reloc. */ + set to -2 if the symbol is used by a reloc. It is set to -3 if + this symbol is defined in a discarded section. */ long indx; /* Symbol index as a dynamic symbol. Initialized to -1, and remains diff --git a/bfd/elflink.c b/bfd/elflink.c index b6ff6b6..6ccd5fc 100644 --- a/bfd/elflink.c +++ b/bfd/elflink.c @@ -4082,6 +4082,7 @@ error_free_dyn: bfd_boolean old_weak; bfd_boolean override; bfd_boolean common; + bfd_boolean discarded; unsigned int old_alignment; bfd *old_bfd; bfd_boolean matched; @@ -4092,6 +4093,7 @@ error_free_dyn: sec = NULL; value = isym->st_value; common = bed->common_definition (isym); + discarded = FALSE; bind = ELF_ST_BIND (isym->st_info); switch (bind) @@ -4142,6 +4144,7 @@ error_free_dyn: /* Symbols from discarded section are undefined. We keep its visibility. */ sec = bfd_und_section_ptr; + discarded = TRUE; isym->st_shndx = SHN_UNDEF; } else if ((abfd->flags & (EXEC_P | DYNAMIC)) != 0) @@ -4385,6 +4388,11 @@ error_free_dyn: || h->root.type == bfd_link_hash_warning) h = (struct elf_link_hash_entry *) h->root.u.i.link; + /* Setting the index to -3 tells elf_link_output_extsym that + this symbol is defined in a discarded section. */ + if (discarded) + h->indx = -3; + *sym_hash = h; new_weak = (flags & BSF_WEAK) != 0; @@ -9201,6 +9209,10 @@ elf_link_output_extsym (struct bfd_hash_entry *bh, void *data) return FALSE; } } + + /* Strip a global symbol defined in a discarded section. */ + if (h->indx == -3) + return TRUE; } /* We should also warn if a forced local symbol is referenced from -- cgit v1.1