PATCH: PR ld/15146: Reference from dummy plugin symbol isn't removed

["H.J. Lu" <hongjiu dot lu at intel dot com>]

Hi,

We shouldn't add DT_NEEDED for references from the dummy bfd, which
may be removed by LTO.  This patch replaces the the undefined dummy bfd
with the real one and avoid adding DT_NEEDED for references from the
dummy bfd.  OK to install?

Thanks.


H.J.
---
bfd/

2013-02-14  H.J. Lu  <hongjiu.lu@intel.com>

	PR ld/15146
	* elflink.c (elf_link_add_object_symbols): Don't add DT_NEEDED
	for references from the dummy bfd.

ld/

2013-02-14  H.J. Lu  <hongjiu.lu@intel.com>

	PR ld/15146
	* plugin.c (plugin_notice): Replace the undefined dummy bfd with
	the real one.

ld/testsuite/

2013-02-14  H.J. Lu  <hongjiu.lu@intel.com>

	PR ld/15146
	* ld-plugin/pr15146.d: New file.
	* ld-plugin/pr15146a.c: Likewise.
	* ld-plugin/pr15146b.c: Likewise.
	* ld-plugin/pr15146c.c: Likewise.
	* ld-plugin/pr15146d.c: Likewise.

	* ld-plugin/lto.exp: Add tests for PR ld/15146.

diff --git a/bfd/elflink.c b/bfd/elflink.c
index d423ca4..a92ff60 100644
--- a/bfd/elflink.c
+++ b/bfd/elflink.c
@@ -4477,10 +4477,13 @@ error_free_dyn:
 		break;
 	      }
 
+	  /* Don't add DT_NEEDED for references from the dummy bfd.  */
 	  if (!add_needed
 	      && definition
 	      && ((dynsym
-		   && h->ref_regular)
+		   && h->ref_regular
+		   && (undef_bfd == NULL
+		       || (undef_bfd->flags & BFD_PLUGIN) == 0))
 		  || (h->ref_dynamic
 		      && (elf_dyn_lib_class (abfd) & DYN_AS_NEEDED) != 0
 		      && !on_needed_list (elf_dt_name (abfd), htab->needed))))
diff --git a/ld/plugin.c b/ld/plugin.c
index da99e77..00f1d75 100644
--- a/ld/plugin.c
+++ b/ld/plugin.c
@@ -993,7 +993,14 @@ plugin_notice (struct bfd_link_info *info,
 
       /* If this is a ref, set non_ir_ref.  */
       else if (bfd_is_und_section (section))
-	h->non_ir_ref = TRUE;
+	{
+	  /* Replace the undefined dummy bfd with the real one.  */
+	  if ((h->type == bfd_link_hash_undefined
+	       || h->type == bfd_link_hash_undefweak)
+	      && (h->u.undef.abfd->flags & BFD_PLUGIN) != 0)
+	    h->u.undef.abfd = abfd;
+	  h->non_ir_ref = TRUE;
+	}
 
       /* Otherwise, it must be a new def.  Ensure any symbol defined
 	 in an IR dummy BFD takes on a new value from a real BFD.
diff --git a/ld/testsuite/ld-plugin/lto.exp b/ld/testsuite/ld-plugin/lto.exp
index 365b988..269dde7 100644
--- a/ld/testsuite/ld-plugin/lto.exp
+++ b/ld/testsuite/ld-plugin/lto.exp
@@ -180,6 +180,24 @@ set lto_link_elf_tests {
   {"PR ld/13244"
    "-shared -O2 -fPIC -flto -fuse-linker-plugin -nostdlib" "-O2 -fno-early-inlining -flto"
    {pr13244.c} {{"readelf" {-s --wide} "pr13244.d"}} "pr13244.so" "c"}
+  {"Build libpr15146a.a"
+   "" "-flto -O2"
+   {pr15146a.c} {} "lib15146a.a"}
+  {"Build pr15146b.so"
+   "-shared" "-O2 -fpic"
+   {pr15146b.c} {} "pr15146b.so" "c"}
+  {"Build pr15146c.so"
+   "-shared tmpdir/pr15146b.so" "-O2 -fpic"
+   {pr15146c.c} {} "pr15146c.so" "c"}
+  {"PR ld/15146 (1)"
+   "-O2 -flto -fuse-linker-plugin -Wl,-rpath-link,. -Wl,--no-copy-dt-needed-entries tmpdir/pr15146a.o tmpdir/pr15146c.so" ""
+   {dummy.c} {{"readelf" {-d} "pr15146.d"}} "pr15146a.exe"}
+  {"Build libpr15146d.a"
+   "" "-flto -O2"
+   {pr15146d.c} {} "lib15146d.a"}
+  {"Build libpr15146d.a"
+   "" "-flto -O2"
+   {pr15146d.c} {} "lib15146d.a"}
 }
 
 # Check final symbols in executables.
@@ -269,6 +287,13 @@ run_cc_link_tests $lto_link_tests
 if { [is_elf_format]
      && [run_host_cmd_yesno $CC "-shared -fPIC $srcdir/$subdir/dummy.c -o tmpdir/t.so"] } {
     run_cc_link_tests $lto_link_elf_tests
+    set testname "PR ld/15146 (2)"
+    set exec_output [run_host_cmd "$CC" "$gcc_gas_flag $gcc_ld_flag -O2 -flto -fuse-linker-plugin -Wl,-rpath-link,. -Wl,--no-copy-dt-needed-entries tmpdir/pr15146d.o tmpdir/pr15146c.so"]
+    if { [ regexp "ltrans.o: undefined reference to symbol 'xxx'" $exec_output ] } {
+	pass $testname
+    } {
+	fail $testname
+    }
 }
 
 set testname "Build liblto-11.a"
diff --git a/ld/testsuite/ld-plugin/pr15146.d b/ld/testsuite/ld-plugin/pr15146.d
new file mode 100644
index 0000000..48d4b85
--- /dev/null
+++ b/ld/testsuite/ld-plugin/pr15146.d
@@ -0,0 +1,4 @@
+#failif
+#...
+ +0x[0-9a-f]+ +\(NEEDED\) +Shared library: +\[.*pr15146b.so\]
+#...
diff --git a/ld/testsuite/ld-plugin/pr15146a.c b/ld/testsuite/ld-plugin/pr15146a.c
new file mode 100644
index 0000000..a22860a
--- /dev/null
+++ b/ld/testsuite/ld-plugin/pr15146a.c
@@ -0,0 +1,13 @@
+extern int xxx;
+
+int
+bar (void)
+{
+  return xxx;
+}
+
+int
+main ()
+{ 
+  return 0;
+}
diff --git a/ld/testsuite/ld-plugin/pr15146b.c b/ld/testsuite/ld-plugin/pr15146b.c
new file mode 100644
index 0000000..90eb21e
--- /dev/null
+++ b/ld/testsuite/ld-plugin/pr15146b.c
@@ -0,0 +1 @@
+int xxx = 3;
diff --git a/ld/testsuite/ld-plugin/pr15146c.c b/ld/testsuite/ld-plugin/pr15146c.c
new file mode 100644
index 0000000..e69de29
diff --git a/ld/testsuite/ld-plugin/pr15146d.c b/ld/testsuite/ld-plugin/pr15146d.c
new file mode 100644
index 0000000..ba1e0ab
--- /dev/null
+++ b/ld/testsuite/ld-plugin/pr15146d.c
@@ -0,0 +1,7 @@
+extern int xxx;
+
+int
+main ()
+{ 
+  return xxx;
+}