[RFC][PATCH v5 6/6] Implement and document -z unique / -z nounique handling in gold

[Vivek Das Mohapatra]

---
 gold/ChangeLog | 6 ++++++
 gold/layout.cc | 6 ++++++
 gold/options.h | 3 +++
 3 files changed, 15 insertions(+)

diff --git a/gold/ChangeLog b/gold/ChangeLog
index f7520ba3cd..2a85fb78d1 100644
--- a/gold/ChangeLog
+++ b/gold/ChangeLog
@@ -1,3 +1,9 @@
+2020-07-10  Vivek Das Mohapatra  <vivek@collabora.com>
+
+	Implement -z unique / -z nounique options.
+	* layout.cc (Layout::finish_dynamic_section): Set DF_GNU_1_UNIQUE.
+	* options.h (class General_options): Handle -z unique, -z nounique.
+
 2020-07-08  Nick Clifton  <nickc@redhat.com>
 
 	* testsuite/script_test_7.sh: Adjust expected address of the .bss
diff --git a/gold/layout.cc b/gold/layout.cc
index 13e533aaf2..9c4fc0d22d 100644
--- a/gold/layout.cc
+++ b/gold/layout.cc
@@ -5358,6 +5358,12 @@ Layout::finish_dynamic_section(const Input_objects* input_objects,
     flags |= elfcpp::DF_1_PIE;
   if (flags != 0)
     odyn->add_constant(elfcpp::DT_FLAGS_1, flags);
+
+  flags = 0;
+  if (parameters->options().unique())
+    flags |= elfcpp::DF_GNU_1_UNIQUE;
+  if (flags != 0)
+    odyn->add_constant(elfcpp::DT_GNU_FLAGS_1, flags);
 }
 
 // Set the size of the _DYNAMIC symbol table to be the size of the
diff --git a/gold/options.h b/gold/options.h
index 3c8d25a662..8902b94a84 100644
--- a/gold/options.h
+++ b/gold/options.h
@@ -1463,6 +1463,9 @@ class General_options
   DEFINE_bool(interpose, options::DASH_Z, '\0', false,
 	      N_("Mark object to interpose all DSOs but executable"),
 	      NULL);
+  DEFINE_bool(unique, options::DASH_Z, '\0', false,
+              N_("Mark DSO to be loaded at most once, and only in the main namespace"),
+              N_("Do not mark the DSO as one to be loaded only in the main namespace"));
   DEFINE_bool_alias(lazy, now, options::DASH_Z, '\0',
 		    N_("Mark object for lazy runtime binding"),
 		    NULL, true);
-- 
2.11.0