Fix symbol resolution with linker plugins for defsym symbols.

2018-02-07  Sriraman Tallam  <tmsriram@google.com>

	* expression.cc (Symbol_expression::set_expr_sym_in_real_elf):
	New method.
	(Unary_expression::set_expr_sym_in_real_elf): New method.
	(Binary_expression::set_expr_sym_in_real_elf): New method.
	(Trinary_expression::set_expr_sym_in_real_elf): New method.
	* plugin.cc (get_symbol_resolution_info): Fix symbol resolution if
	defined or used in defsyms.
	* plugin.h (Plugin_manager::is_defsym_def): New method.
	(Plugin_manager::Plugin_manager): Initialize defsym_defines_set_.
	(Plugin_manager::defsym_defines_set_): New member.
	(Plugin_manager::Defsym_defines_set): New typedef.
	* script.cc (Script_options::set_defsym_uses_in_real_elf): New method.
	(Script_options::find_defsym_defs): New method.
	* script.h (Expression::set_expr_sym_in_real_elf): New method.
	(Symbol_assignment::is_defsym): New method.
	(Symbol_assignment::value): New method.
	(Script_options::find_defsym_defs): New method.
	(Script_options::set_defsym_uses_in_real_elf): New method.
	* testsuite/Makefile.am (plugin_test_defsym): New test.
	* testsuite/Makefile.in: Regenerate.
	* testsuite/plugin_test.c: Check for new symbol resolution.
	* testsuite/plugin_test_defsym.sh: New script.
	* testsuite/plugin_test_defsym.c: New test source.

1 files changed, 12 insertions, 1 deletions

diff --git a/gold/plugin.h b/gold/plugin.h
index db6093d..e64ee07 100644
--- a/gold/plugin.h
+++ b/gold/plugin.h
@@ -146,11 +146,18 @@ class Plugin_manager
       options_(options), workqueue_(NULL), task_(NULL), input_objects_(NULL),
       symtab_(NULL), layout_(NULL), dirpath_(NULL), mapfile_(NULL),
       this_blocker_(NULL), extra_search_path_(), lock_(NULL),
-      initialize_lock_(&lock_)
+      initialize_lock_(&lock_), defsym_defines_set_()
   { this->current_ = plugins_.end(); }
 
   ~Plugin_manager();
 
+  // Returns true if the symbol name is used in the LHS of a defsym.
+  bool
+  is_defsym_def(const char* sym_name) const
+  {
+    return defsym_defines_set_.find(sym_name) != defsym_defines_set_.end();
+  }
+
   // Add a plugin library.
   void
   add_plugin(const char* filename)
@@ -402,6 +409,10 @@ class Plugin_manager
   std::string extra_search_path_;
   Lock* lock_;
   Initialize_lock initialize_lock_;
+
+  // Keep track of all symbols defined by defsym.
+  typedef Unordered_set<std::string> Defsym_defines_set;
+  Defsym_defines_set defsym_defines_set_;
 };