Treat common symbol in executable as definitionusers/hjl/pr19579

Common symbol in executable is a definition, which overrides definition
from shared objects.

bfd/

	PR ld/19579
	* elflink.c (elf_link_add_object_symbols): Treat common symbol
	in executable as definition.

ld/

	PR ld/19579
	* testsuite/ld-elf/pr19579a.c: New file.
	* testsuite/ld-elf/pr19579b.c: Likewise.
	* testsuite/ld-elf/shared.exp (build_tests): Prepare for PR
	ld/19579 test.
	(run_tests): Add a test for PR ld/19579.

4 files changed, 33 insertions, 0 deletions

diff --git a/bfd/elflink.c b/bfd/elflink.c
index 0e3abff5ce4..6c8f948a1d7 100644
--- a/bfd/elflink.c
+++ b/bfd/elflink.c
@@ -4332,6 +4332,10 @@ error_free_dyn:
 	    h->root.u.c.p->alignment_power = align;
 	  else
 	    h->root.u.c.p->alignment_power = old_alignment;
+
+	  /* Common symbol in executable is a definition.  */
+	  if (bfd_link_executable (info))
+	    definition = TRUE;
 	}
 
       if (is_elf_hash_table (htab))
diff --git a/ld/testsuite/ld-elf/pr19579a.c b/ld/testsuite/ld-elf/pr19579a.c
new file mode 100644
index 00000000000..9a47e26de2a
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr19579a.c
@@ -0,0 +1,13 @@
+#include <stdio.h>
+
+int foo[1];
+
+extern int *foo_p (void);
+
+int
+main ()
+{
+  if (foo[0] == 0 && foo == foo_p ())
+    printf ("PASS\n");
+  return 0;
+}
diff --git a/ld/testsuite/ld-elf/pr19579b.c b/ld/testsuite/ld-elf/pr19579b.c
new file mode 100644
index 00000000000..7cd8dc965ff
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr19579b.c
@@ -0,0 +1,7 @@
+int foo[2];
+
+int *
+foo_p (void)
+{
+  return foo;
+}
diff --git a/ld/testsuite/ld-elf/shared.exp b/ld/testsuite/ld-elf/shared.exp
index 678ab1bb31f..7c7a1712731 100644
--- a/ld/testsuite/ld-elf/shared.exp
+++ b/ld/testsuite/ld-elf/shared.exp
@@ -279,6 +279,12 @@ set build_tests {
   {"Build libpr19073.so"
    "-shared -Wl,--version-script=pr19073.map tmpdir/pr19073a.o" "-fPIC"
    {dummy.c} {{readelf {--dyn-syms --wide} pr19073.rd}} "libpr19073.so"}
+  {"Build pr19579a.o"
+   "-r -nostdlib" "-fPIE"
+   {pr19579a.c} {} "pr19073a.o"}
+  {"Build libpr19579.so"
+   "-shared" "-fPIC"
+   {pr19579b.c} {} "libpr19579.so"}
 }
 
 run_cc_link_tests $build_tests
@@ -432,6 +438,9 @@ set run_tests {
     {"Run pr18458"
      "tmpdir/libpr18458a.so tmpdir/libpr18458b.so -z now" ""
      {pr18458c.c} "pr18458" "pass.out"}
+    {"Run pr19579"
+     "-pie -z text tmpdir/pr19579a.o tmpdir/libpr19579.so" ""
+     {dummy.c} "pr19579" "pass.out"}
 }
 
 # NetBSD ELF systems do not currently support the .*_array sections.