re PR ipa/61659 (Extra undefined symbol because of devirtualization)

	PR c++/61659
	PR c++/61687
Revert:
gcc/c-family/
	* c.opt (-fuse-all-virtuals): New.
gcc/cp/
	* decl2.c (mark_all_virtuals): New variable.
	(maybe_emit_vtables): Check it instead of flag_devirtualize.
	(cp_write_global_declarations): Set it and give helpful diagnostic
	if it introduces errors.
	* class.c (finish_struct_1): Check it.

From-SVN: r213308

diff --git a/gcc/c-family/ChangeLog b/gcc/c-family/ChangeLog
index 31d10b0..645b940 100644 (file)
--- a/gcc/c-family/ChangeLog
+++ b/gcc/c-family/ChangeLog
@@ -1,3 +1,10 @@
+2014-07-30  Jason Merrill  <jason@redhat.com>
+
+       PR c++/61659
+       PR c++/61687
+       Revert:
+       * c.opt (-fuse-all-virtuals): New.
+
 2014-07-30  Tom Tromey  <tromey@redhat.com>
 
        PR c/59855

diff --git a/gcc/c-family/c.opt b/gcc/c-family/c.opt
index ac3eb44..f427da1 100644 (file)
--- a/gcc/c-family/c.opt
+++ b/gcc/c-family/c.opt
@@ -1276,10 +1276,6 @@ funsigned-char
 C ObjC C++ ObjC++ LTO Var(flag_signed_char, 0)
 Make \"char\" unsigned by default
 
-fuse-all-virtuals
-C++ ObjC++ Var(flag_use_all_virtuals) Init(1)
-Treat all virtual functions as odr-used
-
 fuse-cxa-atexit
 C++ ObjC++ Var(flag_use_cxa_atexit) Init(DEFAULT_USE_CXA_ATEXIT)
 Use __cxa_atexit to register destructors

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 3d8bf6d..25d9b8a 100644 (file)
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,5 +1,14 @@
 2014-07-30  Jason Merrill  <jason@redhat.com>
 
+       PR c++/61659
+       PR c++/61687
+       Revert:
+       * decl2.c (mark_all_virtuals): New variable.
+       (maybe_emit_vtables): Check it instead of flag_devirtualize.
+       (cp_write_global_declarations): Set it and give helpful diagnostic
+       if it introduces errors.
+       * class.c (finish_struct_1): Check it.
+
        PR lto/53808
        PR c++/61659
        * pt.c (push_template_decl_real): Set DECL_COMDAT on templates.

diff --git a/gcc/cp/class.c b/gcc/cp/class.c
index 0f611e1..235c68a 100644 (file)
--- a/gcc/cp/class.c
+++ b/gcc/cp/class.c
@@ -6408,7 +6408,7 @@ finish_struct_1 (tree t)
         in every translation unit where the class definition appears.  If
         we're devirtualizing, we can look into the vtable even if we
         aren't emitting it.  */
-      if (CLASSTYPE_KEY_METHOD (t) == NULL_TREE || flag_use_all_virtuals)
+      if (CLASSTYPE_KEY_METHOD (t) == NULL_TREE)
        keyed_classes = tree_cons (NULL_TREE, t, keyed_classes);
     }
 

diff --git a/gcc/cp/decl2.c b/gcc/cp/decl2.c
index 884be0a..eafdce5 100644 (file)
--- a/gcc/cp/decl2.c
+++ b/gcc/cp/decl2.c
@@ -106,11 +106,6 @@ static GTY(()) vec<tree, va_gc> *no_linkage_decls;
 /* Nonzero if we're done parsing and into end-of-file activities.  */
 
 int at_eof;
-
-/* Nonzero if we've instantiated everything used directly, and now want to
-   mark all virtual functions as used so that they are available for
-   devirtualization.  */
-static int mark_all_virtuals;
 \f
 
 /* Return a member function type (a METHOD_TYPE), given FNTYPE (a
@@ -2020,15 +2015,6 @@ maybe_emit_vtables (tree ctype)
       if (DECL_COMDAT (primary_vtbl)
          && CLASSTYPE_DEBUG_REQUESTED (ctype))
        note_debug_info_needed (ctype);
-      if (mark_all_virtuals && !DECL_ODR_USED (primary_vtbl))
-       {
-         /* Make sure virtual functions get instantiated/synthesized so that
-            they can be inlined after devirtualization even if the vtable is
-            never emitted.  */
-         mark_used (primary_vtbl);
-         mark_vtable_entries (primary_vtbl);
-         return true;
-       }
       return false;
     }
 
@@ -4345,8 +4331,6 @@ cp_write_global_declarations (void)
      instantiated, etc., etc.  */
 
   emit_support_tinfos ();
-  int errs = errorcount + sorrycount;
-  bool explained_devirt = false;
 
   do
     {
@@ -4579,27 +4563,6 @@ cp_write_global_declarations (void)
                                         pending_statics->length ()))
        reconsider = true;
 
-      if (flag_use_all_virtuals)
-       {
-         if (!reconsider && !mark_all_virtuals)
-           {
-             mark_all_virtuals = true;
-             reconsider = true;
-             errs = errorcount + sorrycount;
-           }
-         else if (mark_all_virtuals
-                  && !explained_devirt
-                  && (errorcount + sorrycount > errs))
-           {
-             inform (global_dc->last_location, "this error is seen due to "
-                     "instantiation of all virtual functions, which the C++ "
-                     "standard says are always considered used; this is done "
-                     "to support devirtualization optimizations, but can be "
-                     "disabled with -fno-use-all-virtuals");
-             explained_devirt = true;
-           }
-       }
-
       retries++;
     }
   while (reconsider);

diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 5dfa586..51757f0 100644 (file)
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -189,7 +189,7 @@ in the following sections.
 -fno-pretty-templates @gol
 -frepo  -fno-rtti  -fstats  -ftemplate-backtrace-limit=@var{n} @gol
 -ftemplate-depth=@var{n} @gol
--fno-threadsafe-statics  -fno-use-all-virtuals  -fuse-cxa-atexit @gol
+-fno-threadsafe-statics  -fuse-cxa-atexit @gol
 -fno-weak  -nostdinc++ @gol
 -fvisibility-inlines-hidden @gol
 -fvtable-verify=@var{std|preinit|none} @gol
@@ -2319,16 +2319,6 @@ ABI for thread-safe initialization of local statics.  You can use this
 option to reduce code size slightly in code that doesn't need to be
 thread-safe.
 
-@item -fno-use-all-virtuals
-@opindex fno-use-all-virtuals
-By default, G++ now treats all virtual functions declared in a
-translation unit as odr-used, so they will be instantiated or
-synthesized if possible even if they are not needed for the final
-output.  This is done so that such functions can be inlined after
-devirtualization changes an indirect call into a direct call.  If this
-instantiation and synthesis prevents your code from compiling
-successfully, you can disable it with this option.
-
 @item -fuse-cxa-atexit
 @opindex fuse-cxa-atexit
 Register destructors for objects with static storage duration with the

diff --git a/gcc/testsuite/g++.dg/template/dtor9.C b/gcc/testsuite/g++.dg/template/dtor9.C
index 006a754..fd71389 100644 (file)
--- a/gcc/testsuite/g++.dg/template/dtor9.C
+++ b/gcc/testsuite/g++.dg/template/dtor9.C
@@ -1,5 +1,4 @@
 // PR c++/60347
-// { dg-options "-fno-use-all-virtuals" }
 
 struct A;
 

diff --git a/gcc/testsuite/g++.dg/template/dtor9a.C b/gcc/testsuite/g++.dg/template/dtor9a.C
deleted file mode 100644 (file)
index aaae8b6..0000000
--- a/gcc/testsuite/g++.dg/template/dtor9a.C
+++ /dev/null
@@ -1,13 +0,0 @@
-// PR c++/60347
-// { dg-options "-fuse-all-virtuals" }
-
-struct A;
-
-template <class T>
-struct B
-{
-  T* p;
-  virtual ~B() { p->~T(); }    // { dg-error "incomplete" }
-};
-
-struct C: B<A> { };