On 3/8/23 11:15, Jason Merrill wrote:
On 3/8/23 10:53, Jan Hubicka wrote:
Tested x86_64-pc-linux-gnu. Does this look good, or do we want to
factor the
flag clearing into a symtab_node counterpart to cgraph_node::reset?
-- 8< --
In 107897, by the time we are looking at the mangling clash, the
alias has already been removed from the symbol table by
analyze_functions,
so we can't look at n->cpp_implicit_alias. So just assume that it's an
alias if it's internal.
In 108887 the problem is that removing the mangling alias from the
symbol
table confuses analyze_functions, because it ended up as first_analyzed
somehow, so it becomes a dangling pointer. Fixed by clearing various
flags
to neutralize the alias.
PR c++/107897
PR c++/108887
gcc/cp/ChangeLog:
* decl2.cc (record_mangling): Improve symbol table handling.
gcc/testsuite/ChangeLog:
* g++.dg/cpp2a/concepts-lambda3.C: Use -flto if supported.
* g++.dg/cpp0x/lambda/lambda-mangle7.C: New test.
---
gcc/cp/decl2.cc | 25 +++++--
.../g++.dg/cpp0x/lambda/lambda-mangle7.C | 70 +++++++++++++++++++
gcc/testsuite/g++.dg/cpp2a/concepts-lambda3.C | 1 +
3 files changed, 91 insertions(+), 5 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/cpp0x/lambda/lambda-mangle7.C
diff --git a/gcc/cp/decl2.cc b/gcc/cp/decl2.cc
index 387e24542cd..e6e58b08de4 100644
--- a/gcc/cp/decl2.cc
+++ b/gcc/cp/decl2.cc
@@ -4742,15 +4742,30 @@ record_mangling (tree decl, bool need_warning)
= mangled_decls->find_slot_with_hash (id, IDENTIFIER_HASH_VALUE
(id),
INSERT);
- /* If this is already an alias, remove the alias, because the real
+ /* If this is already an alias, cancel the alias, because the real
decl takes precedence. */
if (*slot && DECL_ARTIFICIAL (*slot) && DECL_IGNORED_P (*slot))
- if (symtab_node *n = symtab_node::get (*slot))
- if (n->cpp_implicit_alias)
+ {
+ if (symtab_node *n = symtab_node::get (*slot))
{
- n->remove ();
- *slot = NULL_TREE;
+ if (n->cpp_implicit_alias)
+ {
+ /* Actually removing the node isn't safe if other code is
already
+ holding a pointer to it, so just neutralize it. */
+ n->remove_from_same_comdat_group ();
+ n->analyzed = false;
+ n->definition = false;
+ n->alias = false;
+ n->cpp_implicit_alias = false;
We have n->reset () for that which is used in similar situation when
frontends overwrites extern inline function by its different offline
implementation.
The problem there is that reset() is a member of cgraph_node, not
symtab_node, and I need something that works for variables as well.
reset doesn't call remove_from_same_comdat_group probably because it was
never used on anything in comdat group. So I think it would make sense
to call n->reset() here and add remove_from_same_comdat_group into that.
How about moving it to symtab_node and using dyn_cast for the cgraph
bits, like this:
From 1d869ceb04573727e59be6518903133c8654069a Mon Sep 17 00:00:00 2001
From: Jason Merrill <ja...@redhat.com>
Date: Mon, 6 Mar 2023 15:33:45 -0500
Subject: [PATCH] c++: lambda mangling alias issues [PR107897]
To: gcc-patches@gcc.gnu.org
In 107897, by the time we are looking at the mangling clash, the
alias has already been removed from the symbol table by analyze_functions,
so we can't look at n->cpp_implicit_alias. So just assume that it's an
alias if it's internal.
In 108887 the problem is that removing the mangling alias from the symbol
table confuses analyze_functions, because it ended up as first_analyzed
somehow, so it becomes a dangling pointer. Fixed by clearing various flags
to neutralize the alias.
PR c++/107897
PR c++/108887
gcc/ChangeLog:
* cgraph.h: Move reset() from cgraph_node to symtab_node.
* cgraphunit.cc (symtab_node::reset): Adjust.
gcc/cp/ChangeLog:
* decl2.cc (record_mangling): Use symtab_node::reset.
gcc/testsuite/ChangeLog:
* g++.dg/cpp2a/concepts-lambda3.C: Use -flto if supported.
* g++.dg/cpp0x/lambda/lambda-mangle7.C: New test.
---
gcc/cgraph.h | 16 ++---
gcc/cgraphunit.cc | 27 ++++---
gcc/cp/decl2.cc | 19 +++--
.../g++.dg/cpp0x/lambda/lambda-mangle7.C | 70 +++++++++++++++++++
gcc/testsuite/g++.dg/cpp2a/concepts-lambda3.C | 1 +
5 files changed, 109 insertions(+), 24 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/cpp0x/lambda/lambda-mangle7.C
diff --git a/gcc/cgraph.h b/gcc/cgraph.h
index b5fc739f1b0..fb938470be9 100644
--- a/gcc/cgraph.h
+++ b/gcc/cgraph.h
@@ -149,6 +149,14 @@ public:
cgraph/varpool node creation routines. */
void register_symbol (void);
+ /* As an GCC extension we allow redefinition of the function. The
+ semantics when both copies of bodies differ is not well defined.
+ We replace the old body with new body so in unit at a time mode
+ we always use new body, while in normal mode we may end up with
+ old body inlined into some functions and new body expanded and
+ inlined in others. */
+ void reset (void);
+
/* Remove symbol from symbol table. */
void remove (void);
@@ -1066,14 +1074,6 @@ struct GTY((tag ("SYMTAB_FUNCTION"))) cgraph_node : public symtab_node
/* Expand function specified by node. */
void expand (void);
- /* As an GCC extension we allow redefinition of the function. The
- semantics when both copies of bodies differ is not well defined.
- We replace the old body with new body so in unit at a time mode
- we always use new body, while in normal mode we may end up with
- old body inlined into some functions and new body expanded and
- inlined in others. */
- void reset (void);
-
/* Creates a wrapper from cgraph_node to TARGET node. Thunk is used for this
kind of wrapper method. */
void create_wrapper (cgraph_node *target);
diff --git a/gcc/cgraphunit.cc b/gcc/cgraphunit.cc
index a972900900b..2bce529ac81 100644
--- a/gcc/cgraphunit.cc
+++ b/gcc/cgraphunit.cc
@@ -381,18 +381,9 @@ symbol_table::process_new_functions (void)
body for expanding the function but this is difficult to do. */
void
-cgraph_node::reset (void)
+symtab_node::reset (void)
{
- /* If process is set, then we have already begun whole-unit analysis.
- This is *not* testing for whether we've already emitted the function.
- That case can be sort-of legitimately seen with real function redefinition
- errors. I would argue that the front end should never present us with
- such a case, but don't enforce that for now. */
- gcc_assert (!process);
-
/* Reset our data structures so we can analyze the function again. */
- inlined_to = NULL;
- memset (&rtl, 0, sizeof (rtl));
analyzed = false;
definition = false;
alias = false;
@@ -400,8 +391,22 @@ cgraph_node::reset (void)
weakref = false;
cpp_implicit_alias = false;
- remove_callees ();
remove_all_references ();
+ remove_from_same_comdat_group ();
+
+ if (cgraph_node *cn = dyn_cast <cgraph_node *> (this))
+ {
+ /* If process is set, then we have already begun whole-unit analysis.
+ This is *not* testing for whether we've already emitted the function.
+ That case can be sort-of legitimately seen with real function
+ redefinition errors. I would argue that the front end should never
+ present us with such a case, but don't enforce that for now. */
+ gcc_assert (!cn->process);
+
+ memset (&cn->rtl, 0, sizeof (cn->rtl));
+ cn->inlined_to = NULL;
+ cn->remove_callees ();
+ }
}
/* Return true when there are references to the node. INCLUDE_SELF is
diff --git a/gcc/cp/decl2.cc b/gcc/cp/decl2.cc
index 387e24542cd..57713d2ffdc 100644
--- a/gcc/cp/decl2.cc
+++ b/gcc/cp/decl2.cc
@@ -4742,15 +4742,24 @@ record_mangling (tree decl, bool need_warning)
= mangled_decls->find_slot_with_hash (id, IDENTIFIER_HASH_VALUE (id),
INSERT);
- /* If this is already an alias, remove the alias, because the real
+ /* If this is already an alias, cancel the alias, because the real
decl takes precedence. */
if (*slot && DECL_ARTIFICIAL (*slot) && DECL_IGNORED_P (*slot))
- if (symtab_node *n = symtab_node::get (*slot))
- if (n->cpp_implicit_alias)
+ {
+ if (symtab_node *n = symtab_node::get (*slot))
{
- n->remove ();
- *slot = NULL_TREE;
+ if (n->cpp_implicit_alias)
+ /* Actually removing the node isn't safe if other code is already
+ holding a pointer to it, so just neutralize it. */
+ n->reset ();
}
+ else
+ /* analyze_functions might have already removed the alias from the
+ symbol table if it's internal. */
+ gcc_checking_assert (!TREE_PUBLIC (*slot));
+
+ *slot = NULL_TREE;
+ }
if (!*slot)
*slot = decl;
diff --git a/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-mangle7.C b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-mangle7.C
new file mode 100644
index 00000000000..c7946a2be08
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-mangle7.C
@@ -0,0 +1,70 @@
+// PR c++/108887
+// { dg-do compile { target c++11 } }
+
+template <int __v> struct integral_constant {
+ static constexpr int value = __v;
+};
+using false_type = integral_constant<false>;
+template <bool, bool, typename...> struct __result_of_impl;
+template <typename _Functor, typename... _ArgTypes>
+struct __result_of_impl<false, false, _Functor, _ArgTypes...> {
+ typedef decltype(0) type;
+};
+template <typename... _ArgTypes>
+struct __invoke_result
+ : __result_of_impl<false_type::value, false_type::value, _ArgTypes...> {};
+template <typename, typename _Fn, typename... _Args>
+void __invoke_impl(_Fn __f, _Args... __args) {
+ __f(__args...);
+}
+template <typename, typename _Callable, typename... _Args>
+void __invoke_r(_Callable __fn, _Args... __args) {
+ using __result = __invoke_result<_Args...>;
+ using __type = typename __result::type;
+ __invoke_impl<__type>(__fn, __args...);
+}
+struct QString {
+ QString(const char *);
+};
+template <typename> class function;
+template <typename _Functor> struct _Base_manager {
+ static _Functor _M_get_pointer(int) { __builtin_abort (); }
+};
+template <typename, typename> class _Function_handler;
+template <typename _Res, typename _Functor, typename... _ArgTypes>
+struct _Function_handler<_Res(_ArgTypes...), _Functor> {
+ using _Base = _Base_manager<_Functor>;
+ static _Res _M_invoke(const int &__functor, _ArgTypes &&...__args) {
+ auto __trans_tmp_1 = _Base::_M_get_pointer(__functor);
+ __invoke_r<_Res>(__trans_tmp_1, __args...);
+ }
+};
+template <typename _Res, typename... _ArgTypes>
+struct function<_Res(_ArgTypes...)> {
+ template <typename _Functor>
+ using _Handler = _Function_handler<_Res(_ArgTypes...), _Functor>;
+ template <typename _Functor> function(_Functor) {
+ using _My_handler = _Handler<_Functor>;
+ _M_invoker = _My_handler::_M_invoke;
+ }
+ using _Invoker_type = _Res (*)(const int &, _ArgTypes &&...);
+ _Invoker_type _M_invoker;
+};
+struct QRegularExpression {
+ QRegularExpression(QString);
+};
+struct AbstractAccount {
+ void get(function<void(AbstractAccount *)>,
+ function<void(AbstractAccount *)>);
+};
+struct AbstractTimelineModel {
+ AbstractAccount m_account;
+};
+struct LinkPaginationTimelineModel : AbstractTimelineModel {
+ void fillTimeline();
+};
+void LinkPaginationTimelineModel::fillTimeline() {
+ [] {};
+ m_account.get([](AbstractAccount *) { static QRegularExpression re(""); },
+ [](AbstractAccount *) {});
+}
diff --git a/gcc/testsuite/g++.dg/cpp2a/concepts-lambda3.C b/gcc/testsuite/g++.dg/cpp2a/concepts-lambda3.C
index 291e451ca1a..a7cb6c5dece 100644
--- a/gcc/testsuite/g++.dg/cpp2a/concepts-lambda3.C
+++ b/gcc/testsuite/g++.dg/cpp2a/concepts-lambda3.C
@@ -1,4 +1,5 @@
// { dg-do run { target c++20 } }
+// { dg-additional-options "-flto" { target lto } } (PR107897)
template<typename T>
concept C1 = __is_same_as(T, int)
--
2.31.1
