gold patch committed: Warn about undefined protected symbols

[Ian Lance Taylor <iant at google dot com>]

It's an error to refer to a protected/hidden/internal symbol which is
not defined locally.  The dynamic linker will not be able to resolve
such a reference.  I committed this patch to gold to make it gives
error about such cases.

Ian


2010-01-12  Ian Lance Taylor  <iant@google.com>

	* target-reloc.h (visibility_error): New inline function.
	(relocate_section): Call visibility_error.
	* testsuite/Makefile.am (check_DATA): Add protected_3.err.
	(MOSTLYCLEANFILES): Likewise.
	(protected_4_pic.o, protected_3.err): New targets.
	* testsuite/protected_4.cc: New file.


Index: target-reloc.h
===================================================================
RCS file: /cvs/src/src/gold/target-reloc.h,v
retrieving revision 1.38
diff -p -u -r1.38 target-reloc.h
--- target-reloc.h	9 Jan 2010 00:13:48 -0000	1.38
+++ target-reloc.h	12 Jan 2010 19:11:48 -0000
@@ -144,6 +144,31 @@ get_comdat_behavior(const char* name)
   return CB_WARNING;
 }
 
+// Give an error for a symbol with non-default visibility which is not
+// defined locally.
+
+inline void
+visibility_error(const Symbol* sym)
+{
+  const char* v;
+  switch (sym->visibility())
+    {
+    case elfcpp::STV_INTERNAL:
+      v = _("internal");
+      break;
+    case elfcpp::STV_HIDDEN:
+      v = _("hidden");
+      break;
+    case elfcpp::STV_PROTECTED:
+      v = _("protected");
+      break;
+    default:
+      gold_unreachable();
+    }
+  gold_error(_("%s symbol '%s' is not defined locally"),
+	     v, sym->name());
+}
+
 // This function implements the generic part of relocation processing.
 // The template parameter Relocate must be a class type which provides
 // a single function, relocate(), which implements the machine
@@ -323,6 +348,10 @@ relocate_section(
 	  && (!parameters->options().shared()       // -shared
               || parameters->options().defs()))     // -z defs
 	gold_undefined_symbol_at_location(sym, relinfo, i, offset);
+      else if (sym != NULL
+	       && sym->visibility() != elfcpp::STV_DEFAULT
+	       && (sym->is_undefined() || sym->is_from_dynobj()))
+	visibility_error(sym);
 
       if (sym != NULL && sym->has_warning())
 	relinfo->symtab->issue_warning(sym, relinfo, i, offset);
Index: testsuite/Makefile.am
===================================================================
RCS file: /cvs/src/src/gold/testsuite/Makefile.am,v
retrieving revision 1.117
diff -p -u -r1.117 Makefile.am
--- testsuite/Makefile.am	11 Jan 2010 18:34:48 -0000	1.117
+++ testsuite/Makefile.am	12 Jan 2010 19:11:48 -0000
@@ -973,6 +973,18 @@ protected_2_DEPENDENCIES = gcctestdir/ld
 protected_2_LDFLAGS = -Bgcctestdir/ -Wl,-R,.
 protected_2_LDADD = protected_1.so
 
+check_DATA += protected_3.err
+MOSTLYCLEANFILES += protected_3.err
+protected_4_pic.o: protected_4.cc
+	$(CXXCOMPILE) -c -fpic -o $@ $<
+protected_3.err: protected_4_pic.o gcctestdir/ld
+	@echo $(CXXLINK) -Bgcctestdir/ -shared -o protected_4.so protected_4_pic.o "2>$@"
+	@if $(CXXLINK) -Bgcctestdir/ -shared -o protected_4.so protected_4_pic.o 2>$@; then \
+	  echo 1>&2 "Link of protected_4.so should have failed"; \
+	  rm -f $@; \
+	  exit 1; \
+	fi
+
 check_PROGRAMS += relro_test
 relro_test_SOURCES = relro_test_main.cc
 relro_test_DEPENDENCIES = gcctestdir/ld relro_test.so
Index: testsuite/protected_4.cc
===================================================================
RCS file: testsuite/protected_4.cc
diff -N testsuite/protected_4.cc
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ testsuite/protected_4.cc	12 Jan 2010 19:11:49 -0000
@@ -0,0 +1,32 @@
+// protected_4.cc -- a test case for gold
+
+// Copyright 2010 Free Software Foundation, Inc.
+// Written by Ian Lance Taylor <iant@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.
+
+// The function f1 is protected but not defined.
+
+int
+f1() __attribute__ ((__visibility__ ("protected")));
+
+int
+f2()
+{
+  return f1();
+}