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, 20 insertions, 1 deletions

diff --git a/gold/script.h b/gold/script.h
index ec8ce8e..aaf825a 100644
--- a/gold/script.h
+++ b/gold/script.h
@@ -129,13 +129,17 @@ class Expression
   virtual uint64_t
   value(const Expression_eval_info*) = 0;
 
+  // Sets all symbols used in expressions as seen in a real ELF object.
+  virtual void
+  set_expr_sym_in_real_elf(Symbol_table*) const
+  { return; }
+
  private:
   // May not be copied.
   Expression(const Expression&);
   Expression& operator=(const Expression&);
 };
 
-
 // Version_script_info stores information parsed from the version
 // script, either provided by --version-script or as part of a linker
 // script.  A single Version_script_info object per target is owned by
@@ -344,6 +348,14 @@ class Symbol_assignment
   void
   finalize(Symbol_table*, const Layout*);
 
+  bool
+  is_defsym() const
+  { return is_defsym_; }
+
+  Expression *
+  value() const
+  { return val_; }
+
   // Finalize the symbol value when it can refer to the dot symbol.
   void
   finalize_with_dot(Symbol_table*, const Layout*, uint64_t dot_value,
@@ -454,6 +466,13 @@ class Script_options
   bool
   define_symbol(const char* definition);
 
+  // Populates the set with symbol names used in LHS of defsym.
+  void
+  find_defsym_defs(Unordered_set<std::string>&);
+
+  // Set symbols used in defsym expressions as seen in a real ELF object.
+  void set_defsym_uses_in_real_elf(Symbol_table*) const;
+
   // Create sections required by any linker scripts.
   void
   create_script_sections(Layout*);