[PATCH] PR ld/16467: Check incompatible existing default symbol definition

["H.J. Lu" <hjl dot tools at gmail dot com>]

After resolving a versioned reference, foo@VER1, to a default versioned
definition, foo@@VER1, from a shared object, we also merge it with
the existing default symbol definition, foo.  When foo is IFUNC and
foo@@VER1 aren't, we will merge 2 incompatible definitions.  This
patch avoids merging foo@@VER1 definition with foo definition if
one is IFUNC and the other isn't.  OK for trunk and 2.24?

Thanks.

H.J.
---
 bfd/ChangeLog                      |  7 ++++++
 bfd/elflink.c                      | 12 ++++++++++
 ld/testsuite/ChangeLog             | 11 ++++++++++
 ld/testsuite/ld-ifunc/dummy.c      |  1 +
 ld/testsuite/ld-ifunc/ifunc.exp    | 45 ++++++++++++++++++++++++++++++++++++++
 ld/testsuite/ld-ifunc/pr16467.out  |  1 +
 ld/testsuite/ld-ifunc/pr16467a.c   |  5 +++++
 ld/testsuite/ld-ifunc/pr16467a.map |  4 ++++
 ld/testsuite/ld-ifunc/pr16467b.c   |  7 ++++++
 ld/testsuite/ld-ifunc/pr16467b.map |  4 ++++
 ld/testsuite/ld-ifunc/pr16467c.c   |  9 ++++++++
 11 files changed, 106 insertions(+)
 create mode 100644 ld/testsuite/ld-ifunc/dummy.c
 create mode 100644 ld/testsuite/ld-ifunc/pr16467.out
 create mode 100644 ld/testsuite/ld-ifunc/pr16467a.c
 create mode 100644 ld/testsuite/ld-ifunc/pr16467a.map
 create mode 100644 ld/testsuite/ld-ifunc/pr16467b.c
 create mode 100644 ld/testsuite/ld-ifunc/pr16467b.map
 create mode 100644 ld/testsuite/ld-ifunc/pr16467c.c

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index 6e1e334..6daa46c 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,10 @@
+2014-01-19  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR ld/16467
+	* elflink.c (_bfd_elf_add_default_symbol): If the existing
+	default symbol definition is incompatible with the versioned
+	symbol definition, only add the nondefault version of the symbol.
+
 2014-01-16  Alan Modra  <amodra@gmail.com>
 
 	* elfxx-mips.c (mips_elf_record_got_page_entry): Pass in a
diff --git a/bfd/elflink.c b/bfd/elflink.c
index 7dcafd6..279aa39 100644
--- a/bfd/elflink.c
+++ b/bfd/elflink.c
@@ -1623,6 +1623,18 @@ _bfd_elf_add_default_symbol (bfd *abfd,
   memcpy (shortname, name, shortlen);
   shortname[shortlen] = '\0';
 
+  /* If the existing default symbol definition is incompatible with the
+     versioned symbol definition, we only add the nondefault version of
+     the symbol.  */
+  hi = elf_link_hash_lookup (elf_hash_table (info), shortname, FALSE,
+			     FALSE, FALSE);
+  if (hi != NULL
+      && (hi->root.type == bfd_link_hash_defined
+	  || hi->root.type == bfd_link_hash_defweak)
+      && ((hi->type == STT_GNU_IFUNC)
+	  != (ELF_ST_TYPE (sym->st_info) == STT_GNU_IFUNC)))
+    goto nondefault;
+
   /* We are going to create a new symbol.  Merge it with any existing
      symbol with this name.  For the purposes of the merge, act as
      though we were defining the symbol we just defined, although we
diff --git a/ld/testsuite/ChangeLog b/ld/testsuite/ChangeLog
index 8fbd375..3a8d55d 100644
--- a/ld/testsuite/ChangeLog
+++ b/ld/testsuite/ChangeLog
@@ -1,3 +1,14 @@
+2014-01-19  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR ld/16467
+	* ld-ifunc/dummy.c: New file.
+	* ld-ifunc/pr16467.out: Likewise.
+	* ld-ifunc/pr16467a.c: Likewise.
+	* ld-ifunc/pr16467a.map: Likewise.
+	* ld-ifunc/pr16467b.c: Likewise.
+	* ld-ifunc/pr16467b.map: Likewise.
+	* ld-ifunc/pr16467c.c: Likewise.
+
 2014-01-15  Alan Modra  <amodra@gmail.com>
 
 	* ld-elf/ehdr_start-shared.d: New.
diff --git a/ld/testsuite/ld-ifunc/dummy.c b/ld/testsuite/ld-ifunc/dummy.c
new file mode 100644
index 0000000..5c03287
--- /dev/null
+++ b/ld/testsuite/ld-ifunc/dummy.c
@@ -0,0 +1 @@
+/* An empty file.  */
diff --git a/ld/testsuite/ld-ifunc/ifunc.exp b/ld/testsuite/ld-ifunc/ifunc.exp
index fb106c6..d7ff445 100644
--- a/ld/testsuite/ld-ifunc/ifunc.exp
+++ b/ld/testsuite/ld-ifunc/ifunc.exp
@@ -349,6 +349,42 @@ if { $verbose < 1 } {
     remote_file host delete "tmpdir/static_nonifunc_prog"
 }
 
+run_cc_link_tests [list \
+    [list \
+	"Build libpr16467a.so" \
+	"-shared -Wl,--version-script=pr16467a.map" \
+	"-fPIC" \
+	{ pr16467a.c } \
+	{} \
+	"libpr16467a.so" \
+    ] \
+    [list \
+	"Build libpr16467b.a" \
+	"" \
+	"-fPIC" \
+	{ pr16467b.c } \
+	{} \
+	"libpr16467b.a" \
+    ] \
+    [list \
+	"Build libpr16467b.so" \
+	"-shared tmpdir/pr16467b.o tmpdir/libpr16467a.so \
+	 -Wl,--version-script=pr16467b.map" \
+	"-fPIC" \
+	{ dummy.c } \
+	{} \
+	"libpr16467b.so" \
+    ] \
+    [list \
+	"Build libpr16467c.a" \
+	"" \
+	"" \
+	{ pr16467c.c } \
+	{} \
+	"libpr16467c.a" \
+    ] \
+]
+
 run_ld_link_exec_tests [] [list \
     [list \
 	"Common symbol override ifunc test 1a" \
@@ -368,6 +404,15 @@ run_ld_link_exec_tests [] [list \
 	"ifunc-common-1.out" \
 	"-g" \
     ] \
+    [list \
+	"Run pr16467" \
+	"tmpdir/pr16467c.o tmpdir/libpr16467b.so tmpdir/libpr16467a.so" \
+	"" \
+	{ dummy.c } \
+	"pr16467" \
+	"pr16467.out" \
+	"" \
+    ] \
 ]
 
 set test_list [lsort [glob -nocomplain $srcdir/$subdir/*.d]]
diff --git a/ld/testsuite/ld-ifunc/pr16467.out b/ld/testsuite/ld-ifunc/pr16467.out
new file mode 100644
index 0000000..d86bac9
--- /dev/null
+++ b/ld/testsuite/ld-ifunc/pr16467.out
@@ -0,0 +1 @@
+OK
diff --git a/ld/testsuite/ld-ifunc/pr16467a.c b/ld/testsuite/ld-ifunc/pr16467a.c
new file mode 100644
index 0000000..ae3f084
--- /dev/null
+++ b/ld/testsuite/ld-ifunc/pr16467a.c
@@ -0,0 +1,5 @@
+const char * 
+sd_get_seats(void)
+{
+  return "OK";
+}
diff --git a/ld/testsuite/ld-ifunc/pr16467a.map b/ld/testsuite/ld-ifunc/pr16467a.map
new file mode 100644
index 0000000..d677f37
--- /dev/null
+++ b/ld/testsuite/ld-ifunc/pr16467a.map
@@ -0,0 +1,4 @@
+LIBSYSTEMD_209 {
+global:
+        sd_get_seats;
+};
diff --git a/ld/testsuite/ld-ifunc/pr16467b.c b/ld/testsuite/ld-ifunc/pr16467b.c
new file mode 100644
index 0000000..264f6cf
--- /dev/null
+++ b/ld/testsuite/ld-ifunc/pr16467b.c
@@ -0,0 +1,7 @@
+void new_sd_get_seats(void);
+__asm__(".symver new_sd_get_seats,sd_get_seats@LIBSYSTEMD_209");
+void (*resolve_sd_get_seats(void)) (void) __asm__ ("sd_get_seats");
+void (*resolve_sd_get_seats(void)) (void) {
+        return new_sd_get_seats;
+}
+__asm__(".type sd_get_seats, %gnu_indirect_function");
diff --git a/ld/testsuite/ld-ifunc/pr16467b.map b/ld/testsuite/ld-ifunc/pr16467b.map
new file mode 100644
index 0000000..1f263de
--- /dev/null
+++ b/ld/testsuite/ld-ifunc/pr16467b.map
@@ -0,0 +1,4 @@
+LIBSYSTEMD_208 {
+global:
+        sd_get_seats;
+};
diff --git a/ld/testsuite/ld-ifunc/pr16467c.c b/ld/testsuite/ld-ifunc/pr16467c.c
new file mode 100644
index 0000000..e2a901c
--- /dev/null
+++ b/ld/testsuite/ld-ifunc/pr16467c.c
@@ -0,0 +1,9 @@
+#include <stdio.h>
+const char* sd_get_seats(void);
+
+int
+main (int argc, char **argv)
+{
+  printf("%s\n", sd_get_seats());
+  return 0;
+}
-- 
1.8.4.2