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Re: [BFD][PR21703]Override the new defined symbol with the old normal symbol when --allow-multiple-definition is provided
Hi Alan,
On 08/07/17 03:11, Alan Modra wrote:
On Fri, Jul 07, 2017 at 05:41:04PM +0100, Renlin Li wrote:
diff --git a/bfd/elflink.c b/bfd/elflink.c
index 471e8ad..e4ab670 100644
--- a/bfd/elflink.c
+++ b/bfd/elflink.c
@@ -1547,6 +1547,17 @@ _bfd_elf_merge_symbol (bfd *abfd,
sec = *psec;
}
+ /* There are multiple definitions of a normal symbol. */
+ if (olddef && !olddyn && !oldweak && newdef && !newdyn && !newweak
+ && !*matched)
I think !*matched is wrong, and will likely mean the patch doesn't fix
your PR.
I meant to skip the case for versioned symbol. This function will be called with short
name for versioned symbol. That's should be skipped.
I correct the condition and add one more condition for ld plugin case.
+ {
+ /* Handle a multiple definition. */
+ (*info->callbacks->multiple_definition) (info, &h->root,
+ abfd, sec, sym->st_value);
Please use *pvalue here rather than sym->st_value.
Updated.
A new test case is added. The symbol foo in the final object should be of size 4 which
comes from the first object file.
Here, the symbol types are not required to be the same. I think this is the desired behavior?
ld cross and native checked Okay for arm environment. glibc builds Okay with the patched
linker.
Okay?
Regards,
Renlin
ld/ChangeLog:
2017-07-11 Renlin Li <renlin.li@arm.com>
PR ld/21703
* testsuite/ld-elf/elf.exp : Run new test case.
* testsuite/ld-elf/pr21703-1.s: New.
* testsuite/ld-elf/pr21703-2.s: New.
* testsuite/ld-elf/pr21703.sd: New.
bfd/ChangeLog:
2017-07-11 Renlin Li <renlin.li@arm.com>
PR ld/21703
* elflink.c (_bfd_elf_merge_symbol): Handle multiple symbol definition
case.
diff --git a/bfd/elflink.c b/bfd/elflink.c
index 471e8ad..91d2bbb 100644
--- a/bfd/elflink.c
+++ b/bfd/elflink.c
@@ -1036,6 +1036,7 @@ _bfd_elf_merge_symbol (bfd *abfd,
bfd_boolean newweak, oldweak, newfunc, oldfunc;
const struct elf_backend_data *bed;
char *new_version;
+ bfd_boolean versioned_sym = *matched;
*skip = FALSE;
*override = FALSE;
@@ -1547,6 +1548,17 @@ _bfd_elf_merge_symbol (bfd *abfd,
sec = *psec;
}
+ /* There are multiple definitions of a normal symbol. */
+ if (olddef && !olddyn && !oldweak && newdef && !newdyn && !newweak
+ && !versioned_sym && h->def_regular)
+ {
+ /* Handle a multiple definition. */
+ (*info->callbacks->multiple_definition) (info, &h->root,
+ abfd, sec, *pvalue);
+ *skip = TRUE;
+ return TRUE;
+ }
+
/* If both the old and the new symbols look like common symbols in a
dynamic object, set the size of the symbol to the larger of the
two. */
diff --git a/ld/testsuite/ld-elf/elf.exp b/ld/testsuite/ld-elf/elf.exp
index 80a8c42..2dcebb9 100644
--- a/ld/testsuite/ld-elf/elf.exp
+++ b/ld/testsuite/ld-elf/elf.exp
@@ -70,6 +70,12 @@ run_ld_link_tests [list \
{symbol3w.s} {} "symbol3w.a" ] \
]
+run_ld_link_tests [list \
+ [list "PR ld/21703" \
+ "--allow-multiple-definition tmpdir/pr21703-1.o tmpdir/pr21703-2.o" "" "" \
+ {pr21703-1.s pr21703-2.s} {{readelf {-s} pr21703.sd}} "pr21703" ] \
+]
+
if { [check_shared_lib_support] } then {
run_ld_link_tests {
{"Build pr14170a.o" "" "" "" {pr14170a.s} {} "pr14170.a" }
diff --git a/ld/testsuite/ld-elf/pr21703-1.s b/ld/testsuite/ld-elf/pr21703-1.s
new file mode 100644
index 0000000..92a4718
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr21703-1.s
@@ -0,0 +1,6 @@
+ .text
+ .globl foo
+ .type foo, %function
+foo:
+ .space 4
+ .size foo, 4
diff --git a/ld/testsuite/ld-elf/pr21703-2.s b/ld/testsuite/ld-elf/pr21703-2.s
new file mode 100644
index 0000000..1d65304
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr21703-2.s
@@ -0,0 +1,6 @@
+ .text
+ .globl foo
+ .type foo, %function
+foo:
+ .space 16
+ .size foo, 16
diff --git a/ld/testsuite/ld-elf/pr21703.sd b/ld/testsuite/ld-elf/pr21703.sd
new file mode 100644
index 0000000..955cf17
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr21703.sd
@@ -0,0 +1,4 @@
+Symbol table '.symtab' contains .* entries:
+#...
+.*: [0-9a-fA-F]* +4 +FUNC +GLOBAL +DEFAULT +. foo
+#pass