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authorH.J. Lu <hjl.tools@gmail.com>2016-05-05 05:35:01 -0700
committerH.J. Lu <hjl.tools@gmail.com>2016-05-05 05:56:41 -0700
commitea0e05d28045e02c578589217a870d82a1a6b09f (patch)
tree856f7503ce218befebf3bffe861204e6199c35da
parentc175a65796a6f1d6a69ed0d7e3bce6f048c8e983 (diff)
downloadbinutils-gdb-ea0e05d28045e02c578589217a870d82a1a6b09f.tar.gz
Strip global symbol defined in discarded sectionusers/hjl/pr17550
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.
-rw-r--r--bfd/elf-bfd.h3
-rw-r--r--bfd/elflink.c12
-rw-r--r--ld/testsuite/ld-elf/pr17550-1.s9
-rw-r--r--ld/testsuite/ld-elf/pr17550-2.s6
-rw-r--r--ld/testsuite/ld-elf/pr17550-3.s14
-rw-r--r--ld/testsuite/ld-elf/pr17550-4.s15
-rw-r--r--ld/testsuite/ld-elf/pr17550a.d9
-rw-r--r--ld/testsuite/ld-elf/pr17550b.d9
-rw-r--r--ld/testsuite/ld-elf/pr17550c.d4
-rw-r--r--ld/testsuite/ld-elf/pr17550d.d8
10 files changed, 88 insertions, 1 deletions
diff --git a/bfd/elf-bfd.h b/bfd/elf-bfd.h
index 9067dd9aea1..863fc39f2f7 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 b6ff6b650a9..6ccd5fcd139 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
diff --git a/ld/testsuite/ld-elf/pr17550-1.s b/ld/testsuite/ld-elf/pr17550-1.s
new file mode 100644
index 00000000000..3da73dcfa6d
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr17550-1.s
@@ -0,0 +1,9 @@
+ .section .data,"awG",%progbits,foo_group,comdat
+ .dc.a x_alias
+ .type x, %object
+ .p2align 2
+ .size x, 4
+x:
+ .zero 4
+ .globl x_alias
+ .set x_alias,x
diff --git a/ld/testsuite/ld-elf/pr17550-2.s b/ld/testsuite/ld-elf/pr17550-2.s
new file mode 100644
index 00000000000..eb4120f90bc
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr17550-2.s
@@ -0,0 +1,6 @@
+ .section .data,"awG",%progbits,foo_group,comdat
+ .type x, %object
+ .p2align 2
+ .size x, 4
+x:
+ .zero 4
diff --git a/ld/testsuite/ld-elf/pr17550-3.s b/ld/testsuite/ld-elf/pr17550-3.s
new file mode 100644
index 00000000000..3d7c2525bd1
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr17550-3.s
@@ -0,0 +1,14 @@
+ .data
+ .dc.a y
+ .section .data,"awG",%progbits,foo_group,comdat
+ .type y, %object
+ .size y, 4
+y:
+ .zero 4
+ .globl x
+ .type x, %object
+ .size x, 4
+x:
+ .zero 4
+ .globl x_alias
+ .set x_alias,x
diff --git a/ld/testsuite/ld-elf/pr17550-4.s b/ld/testsuite/ld-elf/pr17550-4.s
new file mode 100644
index 00000000000..d0442fd4f05
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr17550-4.s
@@ -0,0 +1,15 @@
+ .data
+ .dc.a y
+ .section .data,"awG",%progbits,foo_group,comdat
+ .globl y
+ .type y, %object
+ .size y, 4
+y:
+ .zero 4
+ .globl x
+ .type x, %object
+ .size x, 4
+x:
+ .zero 4
+ .globl x_alias
+ .set x_alias,x
diff --git a/ld/testsuite/ld-elf/pr17550a.d b/ld/testsuite/ld-elf/pr17550a.d
new file mode 100644
index 00000000000..15a7bc586d3
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr17550a.d
@@ -0,0 +1,9 @@
+#source: pr17550-1.s
+#source: pr17550-2.s
+#ld: -r
+#readelf: -s --wide
+
+#failif
+#...
+ +[0-9]+: +[0-9a-f]+ +0 +OBJECT +GLOBAL +DEFAULT +UND x_alias
+#...
diff --git a/ld/testsuite/ld-elf/pr17550b.d b/ld/testsuite/ld-elf/pr17550b.d
new file mode 100644
index 00000000000..bfa5fde66e5
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr17550b.d
@@ -0,0 +1,9 @@
+#source: pr17550-2.s
+#source: pr17550-1.s
+#ld: -r
+#readelf: -s --wide
+
+#failif
+#...
+ +[0-9]+: +[0-9a-f]+ +0 +OBJECT +GLOBAL +DEFAULT +UND x_alias
+#...
diff --git a/ld/testsuite/ld-elf/pr17550c.d b/ld/testsuite/ld-elf/pr17550c.d
new file mode 100644
index 00000000000..f208c38e47b
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr17550c.d
@@ -0,0 +1,4 @@
+#source: pr17550-2.s
+#source: pr17550-3.s
+#ld: -r
+#error: .*: defined in discarded section `\.data\[foo_group\]'
diff --git a/ld/testsuite/ld-elf/pr17550d.d b/ld/testsuite/ld-elf/pr17550d.d
new file mode 100644
index 00000000000..927caeea57e
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr17550d.d
@@ -0,0 +1,8 @@
+#source: pr17550-2.s
+#source: pr17550-4.s
+#ld: -r
+#readelf: -s --wide
+
+#...
+ +[0-9]+: +[0-9a-f]+ +0 +OBJECT +GLOBAL +DEFAULT +UND y
+#pass