Fix internal error caused by conflicting default version definitions.

gold/
	PR gold/16504
	* dynobj.cc (Versions::symbol_section_contents): Don't set
	VERSYM_HIDDEN flag for undefined symbols.
	* symtab.cc (Symbol_table::add_from_object): Don't override default
	version definition with a different default version.
	* symtab.h (Symbol::from_dyn): New method.
	* testsuite/plugin_test.c (struct sym_info): Add ver field.
	(claim_file_hook): Pass symbol version to plugin API.
	(parse_readelf_line): Parse symbol version.
	* testsuite/Makefile.am (ver_test_pr16504): New test case.
	* testsuite/Makefile.in: Regenerate.
	* testsuite/ver_test_pr16504.sh: New test script.
	* testsuite/ver_test_pr16504_a.c: New source file.
	* testsuite/ver_test_pr16504_a.script: New version script.
	* testsuite/ver_test_pr16504_b.c: New source file.
	* testsuite/ver_test_pr16504_b.script: New version script.

12 files changed, 196 insertions, 22 deletions

diff --git a/gold/ChangeLog b/gold/ChangeLog
index bc17a9ea1f8..e38262e294d 100644
--- a/gold/ChangeLog
+++ b/gold/ChangeLog
@@ -1,3 +1,22 @@
+2018-04-24  Cary Coutant  <ccoutant@gmail.com>
+
+	PR gold/16504
+	* dynobj.cc (Versions::symbol_section_contents): Don't set
+	VERSYM_HIDDEN flag for undefined symbols.
+	* symtab.cc (Symbol_table::add_from_object): Don't override default
+	version definition with a different default version.
+	* symtab.h (Symbol::from_dyn): New method.
+	* testsuite/plugin_test.c (struct sym_info): Add ver field.
+	(claim_file_hook): Pass symbol version to plugin API.
+	(parse_readelf_line): Parse symbol version.
+	* testsuite/Makefile.am (ver_test_pr16504): New test case.
+	* testsuite/Makefile.in: Regenerate.
+	* testsuite/ver_test_pr16504.sh: New test script.
+	* testsuite/ver_test_pr16504_a.c: New source file.
+	* testsuite/ver_test_pr16504_a.script: New version script.
+	* testsuite/ver_test_pr16504_b.c: New source file.
+	* testsuite/ver_test_pr16504_b.script: New version script.
+
 2018-04-19  Cary Coutant  <ccoutant@gmail.com>
 
 	PR gold/23046
diff --git a/gold/dynobj.cc b/gold/dynobj.cc
index d85adbcbe18..7012802d4fe 100644
--- a/gold/dynobj.cc
+++ b/gold/dynobj.cc
@@ -1776,7 +1776,10 @@ Versions::symbol_section_contents(const Symbol_table* symtab,
 	version_index = this->version_index(symtab, dynpool, *p);
       // If the symbol was defined as foo@V1 instead of foo@@V1, add
       // the hidden bit.
-      if ((*p)->version() != NULL && !(*p)->is_default())
+      if ((*p)->version() != NULL
+	  && (*p)->is_defined()
+	  && !(*p)->is_default()
+	  && !(*p)->from_dyn())
         version_index |= elfcpp::VERSYM_HIDDEN;
       elfcpp::Swap<16, big_endian>::writeval(pbuf + (*p)->dynsym_index() * 2,
                                              version_index);
diff --git a/gold/symtab.cc b/gold/symtab.cc
index 34551ace7dd..238834dce88 100644
--- a/gold/symtab.cc
+++ b/gold/symtab.cc
@@ -989,7 +989,7 @@ Symbol_table::add_from_object(Object* object,
   // ins.first->second: the value (Symbol*).
   // ins.second: true if new entry was inserted, false if not.
 
-  Sized_symbol<size>* ret;
+  Sized_symbol<size>* ret = NULL;
   bool was_undefined_in_reg;
   bool was_common;
   if (!ins.second)
@@ -1049,17 +1049,42 @@ Symbol_table::add_from_object(Object* object,
 	  // it, then change it to NAME/VERSION.
 	  ret = this->get_sized_symbol<size>(insdefault.first->second);
 
-	  was_undefined_in_reg = ret->is_undefined() && ret->in_reg();
-	  // Commons from plugins are just placeholders.
-	  was_common = ret->is_common() && ret->object()->pluginobj() == NULL;
-
-	  this->resolve(ret, sym, st_shndx, is_ordinary, orig_st_shndx, object,
-			version, is_default_version);
-          if (parameters->options().gc_sections())
-            this->gc_mark_dyn_syms(ret);
-	  ins.first->second = ret;
+	  // If the existing symbol already has a version,
+	  // don't override it with the new symbol.
+	  // This should only happen when the new symbol
+	  // is from a shared library.
+	  if (ret->version() != NULL)
+	    {
+	      if (!object->is_dynamic())
+	        {
+		  gold_warning(_("%s: conflicting default version definition"
+				 " for %s@@%s"),
+			       object->name().c_str(), name, version);
+		  if (ret->source() == Symbol::FROM_OBJECT)
+		    gold_info(_("%s: %s: previous definition of %s@@%s here"),
+			      program_name,
+			      ret->object()->name().c_str(),
+			      name, ret->version());
+	        }
+	      ret = NULL;
+	      is_default_version = false;
+	    }
+	  else
+	    {
+	      was_undefined_in_reg = ret->is_undefined() && ret->in_reg();
+	      // Commons from plugins are just placeholders.
+	      was_common = (ret->is_common()
+			    && ret->object()->pluginobj() == NULL);
+
+	      this->resolve(ret, sym, st_shndx, is_ordinary, orig_st_shndx,
+			    object, version, is_default_version);
+	      if (parameters->options().gc_sections())
+		this->gc_mark_dyn_syms(ret);
+	      ins.first->second = ret;
+	    }
 	}
-      else
+
+      if (ret == NULL)
 	{
 	  was_undefined_in_reg = false;
 	  was_common = false;
diff --git a/gold/symtab.h b/gold/symtab.h
index fdb75114acd..089e156b452 100644
--- a/gold/symtab.h
+++ b/gold/symtab.h
@@ -344,6 +344,11 @@ class Symbol
   set_in_dyn()
   { this->in_dyn_ = true; }
 
+  // Return whether this symbol is defined in a dynamic object.
+  bool
+  from_dyn() const
+  { return this->source_ == FROM_OBJECT && this->object()->is_dynamic(); }
+
   // Return whether this symbol has been seen in a real ELF object.
   // (IN_REG will return TRUE if the symbol has been seen in either
   // a real ELF object or an object claimed by a plugin.)
diff --git a/gold/testsuite/Makefile.am b/gold/testsuite/Makefile.am
index 7140df64d0d..c926f8ba8fd 100644
--- a/gold/testsuite/Makefile.am
+++ b/gold/testsuite/Makefile.am
@@ -2516,6 +2516,23 @@ plugin_pr22868_b_ir.o: plugin_pr22868_b.c
 plugin_pr22868_b.o: plugin_pr22868_b.c
 	$(COMPILE) -c -fpic -o $@ $<
 
+check_SCRIPTS += ver_test_pr16504.sh
+check_DATA += ver_test_pr16504.stdout
+ver_test_pr16504.stdout: ver_test_pr16504.so
+	$(TEST_READELF) -W --dyn-syms $< >$@ 2>/dev/null
+ver_test_pr16504.so: ver_test_pr16504_a.so ver_test_pr16504_b.o.syms ver_test_pr16504_b.script gcctestdir/ld
+	gcctestdir/ld -shared -o $@ --plugin ./plugin_test.so --version-script $(srcdir)/ver_test_pr16504_b.script ver_test_pr16504_b.o.syms ver_test_pr16504_a.so
+ver_test_pr16504_a.so: ver_test_pr16504_a.o ver_test_pr16504_a.script gcctestdir/ld
+	gcctestdir/ld -shared -o $@ --version-script $(srcdir)/ver_test_pr16504_a.script ver_test_pr16504_a.o
+ver_test_pr16504_a.o: ver_test_pr16504_a.c
+	$(COMPILE) -c -fpic -o $@ $<
+# Filter out the UNDEFs from the symbols file to simulate GCC behavior,
+# which does not pass the UNDEF from a .symver directive.
+ver_test_pr16504_b.o.syms: ver_test_pr16504_b.o
+	$(TEST_READELF) -sW $< 2>/dev/null | grep -v "UND" >$@
+ver_test_pr16504_b.o: ver_test_pr16504_b.c
+	$(COMPILE) -c -fpic -o $@ $<
+
 endif PLUGINS
 
 check_PROGRAMS += exclude_libs_test
diff --git a/gold/testsuite/Makefile.in b/gold/testsuite/Makefile.in
index 48e5b9e2fcc..1e6080721cb 100644
--- a/gold/testsuite/Makefile.in
+++ b/gold/testsuite/Makefile.in
@@ -612,7 +612,8 @@ check_PROGRAMS = $(am__EXEEXT_1) $(am__EXEEXT_2) $(am__EXEEXT_3) \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@	plugin_pr22868.stdout
 @GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@am__append_53 = plugin_final_layout.sh \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@	plugin_layout_with_alignment.sh \
-@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@	plugin_pr22868.sh
+@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@	plugin_pr22868.sh \
+@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@	ver_test_pr16504.sh
 
 # Uses the plugin_final_layout.sh script above to avoid duplication
 @GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@am__append_54 = plugin_final_layout.stdout \
@@ -620,7 +621,8 @@ check_PROGRAMS = $(am__EXEEXT_1) $(am__EXEEXT_2) $(am__EXEEXT_3) \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@	plugin_layout_new_file.stdout \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@	plugin_layout_new_file_readelf.stdout \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@	plugin_layout_with_alignment.stdout \
-@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@	plugin_pr22868.stdout
+@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@	plugin_pr22868.stdout \
+@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@	ver_test_pr16504.stdout
 @GCC_TRUE@@NATIVE_LINKER_TRUE@am__append_55 = exclude_libs_test \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	local_labels_test \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	discard_locals_test
@@ -5368,6 +5370,8 @@ plugin_layout_with_alignment.sh.log: plugin_layout_with_alignment.sh
 	@p='plugin_layout_with_alignment.sh'; $(am__check_pre) $(LOG_COMPILE) "$$tst" $(am__check_post)
 plugin_pr22868.sh.log: plugin_pr22868.sh
 	@p='plugin_pr22868.sh'; $(am__check_pre) $(LOG_COMPILE) "$$tst" $(am__check_post)
+ver_test_pr16504.sh.log: ver_test_pr16504.sh
+	@p='ver_test_pr16504.sh'; $(am__check_pre) $(LOG_COMPILE) "$$tst" $(am__check_post)
 exclude_libs_test.sh.log: exclude_libs_test.sh
 	@p='exclude_libs_test.sh'; $(am__check_pre) $(LOG_COMPILE) "$$tst" $(am__check_post)
 discard_locals_test.sh.log: discard_locals_test.sh
@@ -7220,6 +7224,20 @@ uninstall-am:
 @GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@	$(COMPILE) -c -DIR -fpic -o $@ $<
 @GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@plugin_pr22868_b.o: plugin_pr22868_b.c
 @GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@	$(COMPILE) -c -fpic -o $@ $<
+@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@ver_test_pr16504.stdout: ver_test_pr16504.so
+@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@	$(TEST_READELF) -W --dyn-syms $< >$@ 2>/dev/null
+@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@ver_test_pr16504.so: ver_test_pr16504_a.so ver_test_pr16504_b.o.syms ver_test_pr16504_b.script gcctestdir/ld
+@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@	gcctestdir/ld -shared -o $@ --plugin ./plugin_test.so --version-script $(srcdir)/ver_test_pr16504_b.script ver_test_pr16504_b.o.syms ver_test_pr16504_a.so
+@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@ver_test_pr16504_a.so: ver_test_pr16504_a.o ver_test_pr16504_a.script gcctestdir/ld
+@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@	gcctestdir/ld -shared -o $@ --version-script $(srcdir)/ver_test_pr16504_a.script ver_test_pr16504_a.o
+@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@ver_test_pr16504_a.o: ver_test_pr16504_a.c
+@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@	$(COMPILE) -c -fpic -o $@ $<
+# Filter out the UNDEFs from the symbols file to simulate GCC behavior,
+# which does not pass the UNDEF from a .symver directive.
+@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@ver_test_pr16504_b.o.syms: ver_test_pr16504_b.o
+@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@	$(TEST_READELF) -sW $< 2>/dev/null | grep -v "UND" >$@
+@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@ver_test_pr16504_b.o: ver_test_pr16504_b.c
+@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@	$(COMPILE) -c -fpic -o $@ $<
 @GCC_TRUE@@NATIVE_LINKER_TRUE@exclude_libs_test.syms: exclude_libs_test
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	$(TEST_READELF) -sW $< >$@ 2>/dev/null
 @GCC_TRUE@@NATIVE_LINKER_TRUE@libexclude_libs_test_1.a: exclude_libs_test_1.o
diff --git a/gold/testsuite/plugin_test.c b/gold/testsuite/plugin_test.c
index e80f92626f0..a21abcad4b9 100644
--- a/gold/testsuite/plugin_test.c
+++ b/gold/testsuite/plugin_test.c
@@ -46,6 +46,7 @@ struct sym_info
   char* vis;
   char* sect;
   char* name;
+  char* ver;
 };
 
 static struct claimed_file* first_claimed_file = NULL;
@@ -397,7 +398,14 @@ claim_file_hook (const struct ld_plugin_input_file* file, int* claimed)
           syms[nsyms].name = malloc(len + 1);
           strncpy(syms[nsyms].name, info.name, len + 1);
         }
-      syms[nsyms].version = NULL;
+      if (info.ver == NULL)
+        syms[nsyms].version = NULL;
+      else
+        {
+          len = strlen(info.ver);
+          syms[nsyms].version = malloc(len + 1);
+          strncpy(syms[nsyms].version, info.ver, len + 1);
+        }
       syms[nsyms].def = def;
       syms[nsyms].visibility = vis;
       syms[nsyms].size = info.size;
@@ -676,11 +684,26 @@ parse_readelf_line(char* p, struct sym_info* info)
   p += strspn(p, " ");
 
   /* Name field.  */
-  /* FIXME:  Look for version.  */
-  len = strlen(p);
-  if (len == 0)
-    p = NULL;
-  else if (p[len-1] == '\n')
-    p[--len] = '\0';
-  info->name = p;
+  len = strcspn(p, "@\n");
+  if (len > 0 && p[len] == '@')
+    {
+      /* Get the symbol version.  */
+      char* vp = p + len;
+      int vlen;
+
+      vp += strspn(vp, "@");
+      vlen = strcspn(vp, "\n");
+      vp[vlen] = '\0';
+      if (vlen > 0)
+	info->ver = vp;
+      else
+	info->ver = NULL;
+    }
+  else
+    info->ver = NULL;
+  p[len] = '\0';
+  if (len > 0)
+    info->name = p;
+  else
+    info->name = NULL;
 }
diff --git a/gold/testsuite/ver_test_pr16504.sh b/gold/testsuite/ver_test_pr16504.sh
new file mode 100755
index 00000000000..f4e3b8b0287
--- /dev/null
+++ b/gold/testsuite/ver_test_pr16504.sh
@@ -0,0 +1,41 @@
+#!/bin/sh
+
+# ver_test_pr16504.sh -- test that undef gets correct version with LTO.
+
+# Copyright (C) 2018 Free Software Foundation, Inc.
+# Written by Cary Coutant <ccoutant@gmail.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.
+
+check()
+{
+    if ! grep -q "$2" "$1"
+    then
+	echo "Did not find expected symbol in $1:"
+	echo "   $2"
+	echo ""
+	echo "Actual output below:"
+	cat "$1"
+	exit 1
+    fi
+}
+
+check ver_test_pr16504.stdout " FUNC .* UND  *foo@VER2"
+check ver_test_pr16504.stdout " IFUNC .* foo@@VER1"
+
+exit 0
diff --git a/gold/testsuite/ver_test_pr16504_a.c b/gold/testsuite/ver_test_pr16504_a.c
new file mode 100644
index 00000000000..76280228fad
--- /dev/null
+++ b/gold/testsuite/ver_test_pr16504_a.c
@@ -0,0 +1,5 @@
+const char* foo(void);
+
+const char*
+foo(void)
+{ return "x"; }
diff --git a/gold/testsuite/ver_test_pr16504_a.script b/gold/testsuite/ver_test_pr16504_a.script
new file mode 100644
index 00000000000..86bb0a0355c
--- /dev/null
+++ b/gold/testsuite/ver_test_pr16504_a.script
@@ -0,0 +1,4 @@
+VER2 {
+global:
+  foo;
+};
diff --git a/gold/testsuite/ver_test_pr16504_b.c b/gold/testsuite/ver_test_pr16504_b.c
new file mode 100644
index 00000000000..e6d82b6d37e
--- /dev/null
+++ b/gold/testsuite/ver_test_pr16504_b.c
@@ -0,0 +1,10 @@
+void
+new_foo(void);
+__asm__(".symver new_foo,foo@VER2");
+
+static void (*resolve_foo(void)) (void)
+{
+  return new_foo;
+}
+
+void foo(void) __attribute__((ifunc("resolve_foo")));
diff --git a/gold/testsuite/ver_test_pr16504_b.script b/gold/testsuite/ver_test_pr16504_b.script
new file mode 100644
index 00000000000..94b373dd652
--- /dev/null
+++ b/gold/testsuite/ver_test_pr16504_b.script
@@ -0,0 +1,4 @@
+VER1 {
+global:
+  foo;
+};