From c0221884ecbda8d99a43aa0f5e306638c71533d6 Mon Sep 17 00:00:00 2001 From: Jason Merrill Date: Thu, 10 Jul 2014 15:29:59 -0400 Subject: [PATCH] re PR ipa/61659 (Extra undefined symbol because of devirtualization) PR c++/61659 PR c++/61687 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. * decl.c (grokdeclarator): Clear virtualp after 'virtual auto' error. From-SVN: r212436 --- gcc/c-family/ChangeLog | 6 ++++++ gcc/c-family/c.opt | 4 ++++ gcc/cp/ChangeLog | 11 ++++++++++ gcc/cp/class.c | 2 +- gcc/cp/decl.c | 7 ++++-- gcc/cp/decl2.c | 30 +++++++++++++++++++++++++- gcc/testsuite/g++.dg/template/dtor9.C | 1 + gcc/testsuite/g++.dg/template/dtor9a.C | 13 +++++++++++ 8 files changed, 70 insertions(+), 4 deletions(-) create mode 100644 gcc/testsuite/g++.dg/template/dtor9a.C diff --git a/gcc/c-family/ChangeLog b/gcc/c-family/ChangeLog index 24455978734..23c5c8274a6 100644 --- a/gcc/c-family/ChangeLog +++ b/gcc/c-family/ChangeLog @@ -1,3 +1,9 @@ +2014-07-10 Jason Merrill + + PR c++/61659 + PR c++/61687 + * c.opt (-fuse-all-virtuals): New. + 2014-07-09 Richard Biener PR c-family/61741 diff --git a/gcc/c-family/c.opt b/gcc/c-family/c.opt index faef774e8c4..3a2084f6056 100644 --- a/gcc/c-family/c.opt +++ b/gcc/c-family/c.opt @@ -1268,6 +1268,10 @@ 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 5827bbdf3de..a184a401d9f 100644 --- a/gcc/cp/ChangeLog +++ b/gcc/cp/ChangeLog @@ -1,3 +1,14 @@ +2014-07-10 Jason Merrill + + PR c++/61659 + PR c++/61687 + * 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. + * decl.c (grokdeclarator): Clear virtualp after 'virtual auto' error. + 2014-07-09 Paolo Carlini PR c++/60686 diff --git a/gcc/cp/class.c b/gcc/cp/class.c index 3a44dba9db1..d0eb1033ef2 100644 --- 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_devirtualize) + if (CLASSTYPE_KEY_METHOD (t) == NULL_TREE || flag_use_all_virtuals) keyed_classes = tree_cons (NULL_TREE, t, keyed_classes); } diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c index 1ade5861d58..01d74e34f92 100644 --- a/gcc/cp/decl.c +++ b/gcc/cp/decl.c @@ -9631,8 +9631,11 @@ grokdeclarator (const cp_declarator *declarator, "-std=gnu++1y"); } else if (virtualp) - error ("virtual function cannot " - "have deduced return type"); + { + error ("virtual function cannot " + "have deduced return type"); + virtualp = false; + } } else if (!is_auto (type)) { diff --git a/gcc/cp/decl2.c b/gcc/cp/decl2.c index 98897f4fb92..0926dbc60fc 100644 --- a/gcc/cp/decl2.c +++ b/gcc/cp/decl2.c @@ -106,6 +106,11 @@ static GTY(()) vec *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; /* Return a member function type (a METHOD_TYPE), given FNTYPE (a @@ -2009,7 +2014,7 @@ maybe_emit_vtables (tree ctype) if (DECL_COMDAT (primary_vtbl) && CLASSTYPE_DEBUG_REQUESTED (ctype)) note_debug_info_needed (ctype); - if (flag_devirtualize) + if (mark_all_virtuals) /* Make sure virtual functions get instantiated/synthesized so that they can be inlined after devirtualization even if the vtable is never emitted. */ @@ -4340,6 +4345,8 @@ cp_write_global_declarations (void) instantiated, etc., etc. */ emit_support_tinfos (); + int errs = errorcount + sorrycount; + bool explained_devirt = false; do { @@ -4572,6 +4579,27 @@ 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/testsuite/g++.dg/template/dtor9.C b/gcc/testsuite/g++.dg/template/dtor9.C index fd71389b865..006a75489d6 100644 --- a/gcc/testsuite/g++.dg/template/dtor9.C +++ b/gcc/testsuite/g++.dg/template/dtor9.C @@ -1,4 +1,5 @@ // 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 new file mode 100644 index 00000000000..aaae8b6add0 --- /dev/null +++ b/gcc/testsuite/g++.dg/template/dtor9a.C @@ -0,0 +1,13 @@ +// PR c++/60347 +// { dg-options "-fuse-all-virtuals" } + +struct A; + +template +struct B +{ + T* p; + virtual ~B() { p->~T(); } // { dg-error "incomplete" } +}; + +struct C: B { };