Fix handling of __ehdr_start when it cannot be defined.

2014-05-02  Cary Coutant  <ccoutant@google.com>

	* defstd.cc (in_segment): Define __ehdr_start here...
	* layout.cc (Layout::finalize): ...Instead of here.  Set the
	output segment when known.
	* resolve.cc (Symbol::override_base_with_special): Remember
	the original binding.
	* symtab.cc (Symbol::set_output_segment): New function.
	(Symbol::set_undefined): New function.
	* symtab.h (Symbol::is_weak_undefined): Check original undef
	binding.
	(Symbol::is_strong_undefined): New function.
	(Symbol::set_output_segment): New function.
	(Symbol::set_undefined): New function.
	* target-reloc.h (is_strong_undefined): Remove.
	(issue_undefined_symbol_error): Call Symbol::is_weak_undefined.
	Check for hidden undefs.
	(relocate_section): Call Symbol::is_strong_undefined.

	* testsuite/Makefile.am (ehdr_start_test_1)
	(ehdr_start_test_2, ehdr_start_test_3)
	(ehdr_start_test_4, ehdr_start_test_5): New test cases.
	* testsuite/Makefile.in: Regenerate.
	* testsuite/ehdr_start_def.cc: New source file.
	* testsuite/ehdr_start_test.cc: New source file.
	* testsuite/ehdr_start_test.t: New linker script.
	* testsuite/ehdr_start_test_4.sh: New shell script.

1 files changed, 26 insertions, 0 deletions

diff --git a/gold/testsuite/ehdr_start_def.cc b/gold/testsuite/ehdr_start_def.cc
new file mode 100644
index 0000000..f102a78
--- /dev/null
+++ b/gold/testsuite/ehdr_start_def.cc
@@ -0,0 +1,26 @@
+// ehdr_start_def.cc -- test for __ehdr_start linker-defined symbol.
+
+// Copyright (C) 2014 Free Software Foundation, Inc.
+// Written by Cary Coutant <ccoutant@google.com>.
+
+// This file is part of gold.
+
+// This program is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation; either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program; if not, write to the Free Software
+// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
+// MA 02110-1301, USA.
+
+// We provide a user-defined __ehdr_start, to make sure that the
+// linker does not override this with the linker-defined symbol.
+
+char __ehdr_start[] = { 'a', 'b', 'c', 'd' };