Set non_ir_ref on common symbolusers/hjl/pr20276

Linker backend sets non_ir_ref during relocation scan.  When relocations
are scanned after opening all input files, get_symbols in plugin.c
returns the incorrect symbol resulotion since non_ir_ref isn't set on
common symbols.  plugin_notice should set non_ir_ref on common symbols.
Also, we shouldn't check alignment on symbol from plugin dummy input.

bfd/

	PR ld/20276
	* elflink.c (elf_link_add_object_symbols): Don't check alignment
	on symbol from plugin dummy input.

ld/

	PR ld/20276
	* plugin.c (plugin_notice): Set non_ir_ref on common symbols.
	* testsuite/ld-plugin/lto.exp (lto_link_tests): Add test for
	PR ld/20276.
	(lto_run_tests): Likewise.
	* testsuite/ld-plugin/pass.out: New file.
	* testsuite/ld-plugin/pr20276a.c: Likewise.
	* testsuite/ld-plugin/pr20276b.c: Likewise.

6 files changed, 80 insertions, 47 deletions

diff --git a/bfd/elflink.c b/bfd/elflink.c
index 6d591de58da..d4e8db67ea5 100644
--- a/bfd/elflink.c
+++ b/bfd/elflink.c
@@ -4556,7 +4556,8 @@ error_free_dyn:
 
 	      symbol_align = ffs (h->root.u.def.value) - 1;
 	      if (h->root.u.def.section->owner != NULL
-		  && (h->root.u.def.section->owner->flags & DYNAMIC) == 0)
+		  && (h->root.u.def.section->owner->flags
+		       & (DYNAMIC | BFD_PLUGIN)) == 0)
 		{
 		  normal_align = h->root.u.def.section->alignment_power;
 		  if (normal_align > symbol_align)
diff --git a/ld/plugin.c b/ld/plugin.c
index cb6131841d6..abb685fb22f 100644
--- a/ld/plugin.c
+++ b/ld/plugin.c
@@ -1286,59 +1286,65 @@ plugin_notice (struct bfd_link_info *info,
 	h = h->u.i.link;
 
       /* Nothing to do here if this def/ref is from an IR dummy BFD.  */
-      if (is_ir_dummy_bfd (abfd))
-	;
-
-      /* Making an indirect symbol counts as a reference unless this
-	 is a brand new symbol.  */
-      else if (bfd_is_ind_section (section)
-	       || (flags & BSF_INDIRECT) != 0)
+      if (!is_ir_dummy_bfd (abfd))
 	{
-	  /* ??? Some of this is questionable.  See comments in
-	     _bfd_generic_link_add_one_symbol for case IND.  */
-	  if (h->type != bfd_link_hash_new)
+	  /* Making an indirect symbol counts as a reference unless this
+	     is a brand new symbol.  */
+	  if (bfd_is_ind_section (section)
+	      || (flags & BSF_INDIRECT) != 0)
 	    {
-	      h->non_ir_ref = TRUE;
-	      inh->non_ir_ref = TRUE;
+	      /* ??? Some of this is questionable.  See comments in
+		 _bfd_generic_link_add_one_symbol for case IND.  */
+	      if (h->type != bfd_link_hash_new)
+		{
+		  h->non_ir_ref = TRUE;
+		  inh->non_ir_ref = TRUE;
+		}
+	      else if (inh->type == bfd_link_hash_new)
+		inh->non_ir_ref = TRUE;
 	    }
-	  else if (inh->type == bfd_link_hash_new)
-	    inh->non_ir_ref = TRUE;
-	}
 
-      /* Nothing to do here for warning symbols.  */
-      else if ((flags & BSF_WARNING) != 0)
-	;
+	  /* Nothing to do here for warning symbols.  */
+	  else if ((flags & BSF_WARNING) != 0)
+	    ;
 
-      /* Nothing to do here for constructor symbols.  */
-      else if ((flags & BSF_CONSTRUCTOR) != 0)
-	;
+	  /* Nothing to do here for constructor symbols.  */
+	  else if ((flags & BSF_CONSTRUCTOR) != 0)
+	    ;
 
-      /* If this is a ref, set non_ir_ref.  */
-      else if (bfd_is_und_section (section))
-	{
-	  /* 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 == NULL
-		  || (h->u.undef.abfd->flags & BFD_PLUGIN) != 0))
-	    h->u.undef.abfd = abfd;
-	  h->non_ir_ref = TRUE;
-	}
+	  /* If this is a ref, set non_ir_ref.  */
+	  else if (bfd_is_und_section (section))
+	    {
+	      /* 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 == NULL
+		      || (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.
-	 Weak symbols are not normally overridden by a new weak
-	 definition, and strong symbols will normally cause multiple
-	 definition errors.  Avoid this by making the symbol appear
-	 to be undefined.  */
-      else if (((h->type == bfd_link_hash_defweak
-		 || h->type == bfd_link_hash_defined)
-		&& is_ir_dummy_bfd (sym_bfd = h->u.def.section->owner))
-	       || (h->type == bfd_link_hash_common
-		   && is_ir_dummy_bfd (sym_bfd = h->u.c.p->section->owner)))
-	{
-	  h->type = bfd_link_hash_undefweak;
-	  h->u.undef.abfd = sym_bfd;
+	  /* 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.
+	     Weak symbols are not normally overridden by a new weak
+	     definition, and strong symbols will normally cause multiple
+	     definition errors.  Avoid this by making the symbol appear
+	     to be undefined.  */
+	  else if (((h->type == bfd_link_hash_defweak
+		     || h->type == bfd_link_hash_defined)
+		    && is_ir_dummy_bfd (sym_bfd = h->u.def.section->owner))
+		   || (h->type == bfd_link_hash_common
+		       && is_ir_dummy_bfd (sym_bfd = h->u.c.p->section->owner)))
+	    {
+	      h->type = bfd_link_hash_undefweak;
+	      h->u.undef.abfd = sym_bfd;
+	    }
+
+	  /* If this is a common symbol, set non_ir_ref so that we get
+	     the corrrect symbol resulotion when it is overridden by IR
+	     objects. */
+	  if (bfd_is_com_section (section))
+	    h->non_ir_ref = TRUE;
 	}
     }
 
diff --git a/ld/testsuite/ld-plugin/lto.exp b/ld/testsuite/ld-plugin/lto.exp
index 7a13abbfdb6..9fa73e19cad 100644
--- a/ld/testsuite/ld-plugin/lto.exp
+++ b/ld/testsuite/ld-plugin/lto.exp
@@ -183,6 +183,12 @@ set lto_link_tests [list \
   [list "PR ld/19317 (1)" \
    "$plug_opt" "-flto $lto_no_fat" \
    {pr19317.c} {} "libpr19317.a"] \
+  [list "Build pr20276a.o" \
+   "" "-fno-lto" \
+   {pr20276a.c}] \
+  [list "Build pr20276b.o" \
+   "$plug_opt" "-flto $lto_no_fat" \
+   {pr20276b.c}] \
 ]
 
 if { [at_least_gcc_version 4 7] } {
@@ -332,6 +338,12 @@ set lto_run_tests [list \
   [list "PR ld/19317 (3)" \
    "-O2 -flto tmpdir/pr19317-r.o" "" \
    {dummy.c} "pr19317.exe" "pr19317.out" "-flto -O2" "c"] \
+  [list "PR ld/20267b" \
+   "-O2 -flto tmpdir/pr19317-r.o" "" \
+   {dummy.c} "pr19317.exe" "pr19317.out" "-flto -O2" "c"] \
+  [list "Run pr20276" \
+   "-O2 -flto tmpdir/pr20276a.o tmpdir/pr20267b.o" "" \
+   {dummy.c} "pr20267" "pass.out" "-flto -O2" "c"] \
 ]
 
 if { [at_least_gcc_version 4 7] } {
diff --git a/ld/testsuite/ld-plugin/pass.out b/ld/testsuite/ld-plugin/pass.out
new file mode 100644
index 00000000000..7ef22e9a431
--- /dev/null
+++ b/ld/testsuite/ld-plugin/pass.out
@@ -0,0 +1 @@
+PASS
diff --git a/ld/testsuite/ld-plugin/pr20276a.c b/ld/testsuite/ld-plugin/pr20276a.c
new file mode 100644
index 00000000000..0b37bc7d309
--- /dev/null
+++ b/ld/testsuite/ld-plugin/pr20276a.c
@@ -0,0 +1,12 @@
+#include <stdio.h>
+
+int global_var;
+extern void abort ();
+
+int main(void)
+{
+  if (global_var != 20)
+    abort ();
+  printf ("PASS\n");
+  return 0;
+}
diff --git a/ld/testsuite/ld-plugin/pr20276b.c b/ld/testsuite/ld-plugin/pr20276b.c
new file mode 100644
index 00000000000..2ecbc2ca908
--- /dev/null
+++ b/ld/testsuite/ld-plugin/pr20276b.c
@@ -0,0 +1 @@
+int global_var = 20;