[binutils-gdb] Override the previous definition from IR object

[H.J.Lu <hjl at sourceware dot org>]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=fbcc8bafeb413a111cd3caab39b3ab57d5b8ce93

commit fbcc8bafeb413a111cd3caab39b3ab57d5b8ce93
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Fri Dec 7 15:39:49 2018 -0800

    Override the previous definition from IR object
    
    Mark the previous definition from IR object as undefined so that the
    generic linker will override it.
    
    bfd/
    
    	PR ld/23958
    	* elflink.c (_bfd_elf_add_default_symbol): Override the previous
    	definition from IR object.
    
    ld/
    
    	PR ld/23958
    	* testsuite/ld-plugin/lto.exp: Run PR ld/23958 test.
    	* testsuite/ld-plugin/pr23958.c: New file.
    	* testsuite/ld-plugin/pr23958.t: Likewise.

Diff:
---
 bfd/ChangeLog                    | 6 ++++++
 bfd/elflink.c                    | 9 +++++++++
 ld/ChangeLog                     | 7 +++++++
 ld/testsuite/ld-plugin/lto.exp   | 6 ++++++
 ld/testsuite/ld-plugin/pr23958.c | 6 ++++++
 ld/testsuite/ld-plugin/pr23958.t | 4 ++++
 6 files changed, 38 insertions(+)

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index 85277a1..aa8be34 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,9 @@
+2018-12-07  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR ld/23958
+	* elflink.c (_bfd_elf_add_default_symbol): Override the previous
+	definition from IR object.
+
 2018-12-08  Stafford Horne  <shorne@gmail.com>
 
 	* elf32-or1k.c (or1k_grok_prstatus): New function.
diff --git a/bfd/elflink.c b/bfd/elflink.c
index 4eca389..8992a50 100644
--- a/bfd/elflink.c
+++ b/bfd/elflink.c
@@ -1941,6 +1941,15 @@ _bfd_elf_add_default_symbol (bfd *abfd,
       if (! bfd_link_relocatable (info))
 	{
 	  bh = &hi->root;
+	  if (bh->type == bfd_link_hash_defined
+	      && (bh->u.def.section->owner->flags & BFD_PLUGIN) != 0)
+	    {
+	      /* Mark the previous definition from IR object as
+		 undefined so that the generic linker will override
+		 it.  */
+	      bh->type = bfd_link_hash_undefined;
+	      bh->u.undef.abfd = bh->u.def.section->owner;
+	    }
 	  if (! (_bfd_generic_link_add_one_symbol
 		 (info, abfd, shortname, BSF_INDIRECT,
 		  bfd_ind_section_ptr,
diff --git a/ld/ChangeLog b/ld/ChangeLog
index c8c48c5..75c9c7d 100644
--- a/ld/ChangeLog
+++ b/ld/ChangeLog
@@ -1,5 +1,12 @@
 2018-12-07  H.J. Lu  <hongjiu.lu@intel.com>
 
+	PR ld/23958
+	* testsuite/ld-plugin/lto.exp: Run PR ld/23958 test.
+	* testsuite/ld-plugin/pr23958.c: New file.
+	* testsuite/ld-plugin/pr23958.t: Likewise.
+
+2018-12-07  H.J. Lu  <hongjiu.lu@intel.com>
+
 	* NEWS: Updated for property change report.
 	* ld.texi: Document property change report.
 	* ldmain.c (main): Set link_info.has_map_file to TRUE when
diff --git a/ld/testsuite/ld-plugin/lto.exp b/ld/testsuite/ld-plugin/lto.exp
index 008bde7..b56bd63 100644
--- a/ld/testsuite/ld-plugin/lto.exp
+++ b/ld/testsuite/ld-plugin/lto.exp
@@ -225,6 +225,12 @@ set lto_link_tests [list \
    {pr23818a.c pr23818b.c} \
    {{"readelf" {-s --wide} "pr23818.d"}} \
    "libpr23818.so"] \
+  [list "Build libpr23958.so" \
+   "-shared -flto -Wl,-version-script,pr23958.t" \
+   "-g -flto $lto_fat" \
+   {pr23958.c} \
+   "" \
+   "libpr23958.so"] \
 ]
 
 if { [at_least_gcc_version 4 7] } {
diff --git a/ld/testsuite/ld-plugin/pr23958.c b/ld/testsuite/ld-plugin/pr23958.c
new file mode 100644
index 0000000..656dc31
--- /dev/null
+++ b/ld/testsuite/ld-plugin/pr23958.c
@@ -0,0 +1,6 @@
+void
+dwarf_bytesize (void)
+{
+}
+
+asm (".symver dwarf_bytesize,dwarf_bytesize@@@ELFUTILS_0.143");
diff --git a/ld/testsuite/ld-plugin/pr23958.t b/ld/testsuite/ld-plugin/pr23958.t
new file mode 100644
index 0000000..d3af1ae
--- /dev/null
+++ b/ld/testsuite/ld-plugin/pr23958.t
@@ -0,0 +1,4 @@
+ELFUTILS_0.143 {
+global:
+  dwarf_bytesize;
+};