PR26979, Visibility of undefined foo@v1 should constrain foo@@v1

Also, undefined foo should constrain the visibility of foo@@v1 just as
it does for a later plain foo definition.

bfd/
	PR 26979
	* elf-bfd.h (elf_backend_merge_symbol_attribute): Update prototype.
	* elf32-m68hc1x.h (elf32_m68hc11_merge_symbol_attribute): Likewise.
	* elfxx-mips.h (_bfd_mips_elf_merge_symbol_attribute): Likewise.
	* elfxx-x86.h (_bfd_x86_elf_merge_symbol_attribute): Likewise.
	* elf32-m68hc1x.c (elf32_m68hc11_merge_symbol_attribute): Replace
	isym parameter with st_other.  Adjust code.
	* elf64-alpha.c (elf64_alpha_merge_symbol_attribute): Likewise.
	* elf64-ppc.c (ppc64_elf_merge_symbol_attribute): Likewise.
	* elfnn-aarch64.c (elfNN_aarch64_merge_symbol_attribute): Likewise.
	* elfxx-mips.c (_bfd_mips_elf_merge_symbol_attribute): Likewise.
	* elfxx-x86.c (_bfd_x86_elf_merge_symbol_attribute): Likewise.
	* elflink.c (elf_merge_st_other): Likewise.
	(_bfd_elf_merge_symbol, elf_link_add_object_symbols): Adjust to suit.
	(_bfd_elf_copy_link_hash_symbol_type): Likewise.
	(_bfd_elf_add_default_symbol): Merge st_other from undecorated
	symbol and @VER symbol to @@VER symbol.
ld/
	* testsuite/ld-elf/pr26979a.s,
	* testsuite/ld-elf/pr26979b.s,
	* testsuite/ld-elf/pr26979c.s,
	* testsuite/ld-elf/pr26979.ver,
	* testsuite/ld-elf/pr26979a.d,
	* testsuite/ld-elf/pr26979b.d: New tests.

7 files changed, 44 insertions, 0 deletions

diff --git a/ld/ChangeLog b/ld/ChangeLog
index 9dbb473..7e09a2f 100644
--- a/ld/ChangeLog
+++ b/ld/ChangeLog
@@ -1,3 +1,12 @@
+2020-12-01  Alan Modra  <amodra@gmail.com>
+
+	* testsuite/ld-elf/pr26979a.s,
+	* testsuite/ld-elf/pr26979b.s,
+	* testsuite/ld-elf/pr26979c.s,
+	* testsuite/ld-elf/pr26979.ver,
+	* testsuite/ld-elf/pr26979a.d,
+	* testsuite/ld-elf/pr26979b.d: New tests.
+
 2020-11-29  H.J. Lu  <hongjiu.lu@intel.com>
 
 	PR ld/26936
diff --git a/ld/testsuite/ld-elf/pr26979.ver b/ld/testsuite/ld-elf/pr26979.ver
new file mode 100644
index 0000000..46ddd30
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr26979.ver
@@ -0,0 +1 @@
+v1 {};
diff --git a/ld/testsuite/ld-elf/pr26979a.d b/ld/testsuite/ld-elf/pr26979a.d
new file mode 100644
index 0000000..1b42598
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr26979a.d
@@ -0,0 +1,12 @@
+#source: pr26979a.s
+#source: pr26979c.s
+#target: [check_shared_lib_support]
+#as:
+#ld: -shared --version-script=pr26979.ver
+#readelf: -sW
+
+#...
+.* GLOBAL PROTECTED .*foo@@v1
+#...
+.* GLOBAL PROTECTED .*foo@@v1
+#pass
diff --git a/ld/testsuite/ld-elf/pr26979a.s b/ld/testsuite/ld-elf/pr26979a.s
new file mode 100644
index 0000000..c70c756
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr26979a.s
@@ -0,0 +1,3 @@
+ .protected foo
+ .data
+ .dc.a foo
diff --git a/ld/testsuite/ld-elf/pr26979b.d b/ld/testsuite/ld-elf/pr26979b.d
new file mode 100644
index 0000000..0697368
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr26979b.d
@@ -0,0 +1,12 @@
+#source: pr26979b.s
+#source: pr26979c.s
+#target: [check_shared_lib_support]
+#as:
+#ld: -shared --version-script=pr26979.ver
+#readelf: -sW
+
+#...
+.* GLOBAL PROTECTED .*foo@@v1
+#...
+.* GLOBAL PROTECTED .*foo@@v1
+#pass
diff --git a/ld/testsuite/ld-elf/pr26979b.s b/ld/testsuite/ld-elf/pr26979b.s
new file mode 100644
index 0000000..e078857
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr26979b.s
@@ -0,0 +1,4 @@
+ .protected foo_v1
+ .symver foo_v1, foo@v1
+ .data
+ .dc.a foo_v1
diff --git a/ld/testsuite/ld-elf/pr26979c.s b/ld/testsuite/ld-elf/pr26979c.s
new file mode 100644
index 0000000..f74dc1c
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr26979c.s
@@ -0,0 +1,3 @@
+ .globl foo
+ .symver foo, foo@@@v1
+foo: