public inbox for gcc-cvs@sourceware.org
help / color / mirror / Atom feed
* [gcc(refs/users/marxin/heads/PR94314-fix-new-delete-pair-deletion-part-3)] c++: lambdas with internal linkage are different to no-linkage [PR94426]
@ 2020-04-14 6:39 Martin Liska
0 siblings, 0 replies; only message in thread
From: Martin Liska @ 2020-04-14 6:39 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:8d213cbbe1856e6088282aa0076646cec694b030
commit 8d213cbbe1856e6088282aa0076646cec694b030
Author: Nathan Sidwell <nathan@acm.org>
Date: Mon Apr 13 06:35:33 2020 -0700
c++: lambdas with internal linkage are different to no-linkage [PR94426]
My fix for 94147 was confusing no-linkage with internal linkage, at
the language level. That's wrong. (the std is confusing here, because
it describes linkage of names (which is wrong), and lambdas have no
names)
Lambdas with extra-scope, have linkage. However, at the
implementation-level that linkage is at least as restricted as the
linkage of the extra-scope decl.
Further, when instantiating a variable initialized by a lambda, we
must determine the visibility of the variable itself, before
instantiating its initializer. If the template arguments are internal
(or no-linkage), the variable will have internal linkage, regardless
of the linkage of the template it is instantiated from. We need to
know that before instantiating the lambda, so we can restrict its
linkage correctly.
* decl2.c (determine_visibility): A lambda's visibility is
affected by its extra scope.
* pt.c (instantiate_decl): Determine var's visibility before
instantiating its initializer.
* tree.c (no_linkage_check): Revert code looking at visibility of
lambda's extra scope.
` gcc/cp/
* g++.dg/cpp0x/lambda/pr94426-[12].C: New.
* g++.dg/abi/lambda-vis.C: Drop a warning.
* g++.dg/cpp0x/lambda/lambda-mangle.C: Lambda visibility on
variable changes.
* g++.dg/opt/dump1.C: Drop warnings of no import.
Diff:
---
gcc/cp/ChangeLog | 10 ++++++++++
gcc/cp/decl2.c | 15 +++++++++++++++
gcc/cp/pt.c | 8 ++++++++
gcc/cp/tree.c | 18 ++++--------------
gcc/testsuite/ChangeLog | 9 +++++++++
gcc/testsuite/g++.dg/abi/lambda-vis.C | 2 +-
gcc/testsuite/g++.dg/cpp0x/lambda/lambda-mangle.C | 7 +++++--
gcc/testsuite/g++.dg/cpp0x/lambda/pr94426-1.C | 17 +++++++++++++++++
gcc/testsuite/g++.dg/cpp0x/lambda/pr94426-2.C | 20 ++++++++++++++++++++
gcc/testsuite/g++.dg/opt/dump1.C | 8 ++++----
10 files changed, 93 insertions(+), 21 deletions(-)
diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 27c79be4034..9de64c0f1ac 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,13 @@
+2020-04-13 Nathan Sidwell <nathan@acm.org>
+
+ PR c++/94426 lambdas with internal linkage are different to no-linkage
+ * decl2.c (determine_visibility): A lambda's visibility is
+ affected by its extra scope.
+ * pt.c (instantiate_decl): Determine var's visibility before
+ instantiating its initializer.
+ * tree.c (no_linkage_check): Revert code looking at visibility of
+ lambda's extra scope.
+`
2020-04-10 Iain Sandoe <iain@sandoe.co.uk>
PR c++/94528
diff --git a/gcc/cp/decl2.c b/gcc/cp/decl2.c
index 6cf72b432e2..293df990435 100644
--- a/gcc/cp/decl2.c
+++ b/gcc/cp/decl2.c
@@ -2527,6 +2527,21 @@ determine_visibility (tree decl)
else if (DECL_LANG_SPECIFIC (decl) && DECL_USE_TEMPLATE (decl))
template_decl = decl;
+ if (TREE_CODE (decl) == TYPE_DECL
+ && LAMBDA_TYPE_P (TREE_TYPE (decl))
+ && CLASSTYPE_LAMBDA_EXPR (TREE_TYPE (decl)) != error_mark_node)
+ if (tree extra = LAMBDA_TYPE_EXTRA_SCOPE (TREE_TYPE (decl)))
+ {
+ /* The lambda's visibility is limited by that of its extra
+ scope. */
+ int vis = 0;
+ if (TYPE_P (extra))
+ vis = type_visibility (extra);
+ else
+ vis = expr_visibility (extra);
+ constrain_visibility (decl, vis, false);
+ }
+
/* If DECL is a member of a class, visibility specifiers on the
class can influence the visibility of the DECL. */
tree class_type = NULL_TREE;
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 050a57b2e2e..0a8ec3198d2 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -25541,6 +25541,14 @@ instantiate_decl (tree d, bool defer_ok, bool expl_inst_class_mem_p)
c_inhibit_evaluation_warnings = 0;
}
+ if (VAR_P (d))
+ {
+ /* The variable might be a lambda's extra scope, and that
+ lambda's visibility depends on D's. */
+ maybe_commonize_var (d);
+ determine_visibility (d);
+ }
+
/* Mark D as instantiated so that recursive calls to
instantiate_decl do not try to instantiate it again. */
DECL_TEMPLATE_INSTANTIATED (d) = 1;
diff --git a/gcc/cp/tree.c b/gcc/cp/tree.c
index d1192b7e094..1d311b0fe61 100644
--- a/gcc/cp/tree.c
+++ b/gcc/cp/tree.c
@@ -2780,9 +2780,10 @@ verify_stmt_tree (tree t)
cp_walk_tree (&t, verify_stmt_tree_r, &statements, NULL);
}
-/* Check if the type T depends on a type with no linkage and if so, return
- it. If RELAXED_P then do not consider a class type declared within
- a vague-linkage function to have no linkage. */
+/* Check if the type T depends on a type with no linkage and if so,
+ return it. If RELAXED_P then do not consider a class type declared
+ within a vague-linkage function to have no linkage. Remember:
+ no-linkage is not the same as internal-linkage*/
tree
no_linkage_check (tree t, bool relaxed_p)
@@ -2801,17 +2802,6 @@ no_linkage_check (tree t, bool relaxed_p)
tree extra = LAMBDA_TYPE_EXTRA_SCOPE (t);
if (!extra)
return t;
-
- /* If the mangling scope is internal-linkage or not repeatable
- elsewhere, the lambda effectively has no linkage. (Sadly
- we're not very careful with the linkages of types.) */
- if (TREE_CODE (extra) == VAR_DECL
- && !(TREE_PUBLIC (extra)
- && (processing_template_decl
- || (DECL_LANG_SPECIFIC (extra) && DECL_USE_TEMPLATE (extra))
- /* DECL_COMDAT is set too late for us to check. */
- || DECL_VAR_DECLARED_INLINE_P (extra))))
- return t;
}
/* Otherwise there's no point in checking linkage on template functions; we
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index b1f232ec0e6..9f644531306 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,12 @@
+2020-04-13 Nathan Sidwell <nathan@acm.org>
+
+ PR c++/94426
+ * g++.dg/cpp0x/lambda/pr94426-[12].C: New.
+ * g++.dg/abi/lambda-vis.C: Drop a warning.
+ * g++.dg/cpp0x/lambda/lambda-mangle.C: Lambda visibility on
+ variable changes.
+ * g++.dg/opt/dump1.C: Drop warnings of no import.
+
2020-04-13 Jozef Lawrynowicz <jozef.l@mittosystems.com>
* gcc.target/msp430/operand-modifiers.c: New test.
diff --git a/gcc/testsuite/g++.dg/abi/lambda-vis.C b/gcc/testsuite/g++.dg/abi/lambda-vis.C
index 89683b2076a..c1033f501a3 100644
--- a/gcc/testsuite/g++.dg/abi/lambda-vis.C
+++ b/gcc/testsuite/g++.dg/abi/lambda-vis.C
@@ -2,7 +2,7 @@
// { dg-options "-fno-inline" }
template<typename T> int sfoo (T); // { dg-warning "used but never defined" }
-template<typename T> int gfoo (T); // { dg-warning "used but never defined" }
+template<typename T> int gfoo (T); // OK, but not completable
template<typename T> int ifoo (T); // OK
template<typename T> struct Wrapper {};
template<typename T> Wrapper<T> capture (T &&) {return Wrapper<T> ();}
diff --git a/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-mangle.C b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-mangle.C
index 7894ef3051e..ef4bad8698b 100644
--- a/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-mangle.C
+++ b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-mangle.C
@@ -54,9 +54,12 @@ void bar()
[]{}();
}
-// lambdas used in non-template, non-class body initializers are internal.
+// lambdas used in namespace-scope initializers have the linkage of
+// the decl
// { dg-final { scan-assembler-not "weak\[^\n\r\]*_ZNKUlv" } }
-// { dg-final { scan-assembler-not "weak\[^\n\r\]*variable" } }
+// { dg-final { scan-assembler "weak\[^\n\r\]*variableMUlvE_clEv" { target c++14_down } } }
+// in c++17 and up, this operator() become constexpr, no not emitted
+// { dg-final { scan-assembler-not "weak\[^\n\r\]*variableMUlvE_clEv" { target c++17 } } }
int variable = []{return 1;}();
// And a template instantiated with such a lambda is also internal.
diff --git a/gcc/testsuite/g++.dg/cpp0x/lambda/pr94426-1.C b/gcc/testsuite/g++.dg/cpp0x/lambda/pr94426-1.C
new file mode 100644
index 00000000000..ae7cbf03091
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/lambda/pr94426-1.C
@@ -0,0 +1,17 @@
+// { dg-do compile { target c++14 } }
+// PR 94426 ICE mangling lambda
+// { dg-options {-flto -O2} }
+
+template <bool> using Void = void;
+
+template <typename U> bool Init (U) {return true;}
+template <typename> bool VAR = Init ([] {});
+
+template <typename T>
+Void<false && VAR<T>> Foo (T)
+{}
+
+void q ()
+{
+ Foo ([] {});
+}
diff --git a/gcc/testsuite/g++.dg/cpp0x/lambda/pr94426-2.C b/gcc/testsuite/g++.dg/cpp0x/lambda/pr94426-2.C
new file mode 100644
index 00000000000..3db864c604b
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/lambda/pr94426-2.C
@@ -0,0 +1,20 @@
+// { dg-do compile { target c++14 } }
+// PR 94426 ICE mangling lambda
+
+template <bool> using Void = void;
+
+template <typename U> bool Init (U) {return true;}
+template <typename> bool VAR = Init ([] {});
+
+template <typename T>
+Void<false && VAR<T>> Foo (T)
+{}
+
+void q ()
+{
+ Foo ([] {});
+}
+
+// The instantiation of VAR becomes local
+// { dg-final { scan-assembler {.local _Z3VARIZ1qvEUlvE_E} { target { i?86-*-* x86_64-*-* } } } }
+// { dg-final { scan-assembler {.comm _Z3VARIZ1qvEUlvE_E,1,1} { target { i?86-*-* x86_64-*-* } } } }
diff --git a/gcc/testsuite/g++.dg/opt/dump1.C b/gcc/testsuite/g++.dg/opt/dump1.C
index f813044456c..38ed055d5c6 100644
--- a/gcc/testsuite/g++.dg/opt/dump1.C
+++ b/gcc/testsuite/g++.dg/opt/dump1.C
@@ -312,7 +312,7 @@ namespace std __attribute__ ((__visibility__ ("default")))
typename __add_ref<
typename tuple_element<__i, tuple<_Elements...>>::type
>::type
- get(tuple<_Elements...>& __t) noexcept; // { dg-warning "used but never defined" }
+ get(tuple<_Elements...>& __t) noexcept;
template<std::size_t... _Indexes>
struct _Index_tuple
{};
@@ -387,7 +387,7 @@ namespace std __attribute__ ((__visibility__ ("default")))
};
template<typename _Callable, typename... _Args>
typename _Bind_simple_helper<_Callable, _Args...>::__type
- __bind_simple(_Callable&& __callable, _Args&&... __args) // { dg-warning "used but never defined" }
+ __bind_simple(_Callable&& __callable, _Args&&... __args)
;
union _Any_data
;
@@ -404,7 +404,7 @@ namespace std __attribute__ ((__visibility__ ("default")))
{
protected:
static _Functor*
- _M_get_pointer(const _Any_data& __source) // { dg-warning "used but never defined" }
+ _M_get_pointer(const _Any_data& __source)
;
};
};
@@ -511,7 +511,7 @@ namespace std __attribute__ ((__visibility__ ("default")))
_S_construct(_Alloc&, _Tp* __p, _Args&&... __args)
{ ::new((void*)__p) _Tp(std::forward<_Args>(__args)...); }
static pointer
- allocate(_Alloc& __a, size_type __n) // { dg-warning "used but never defined" }
+ allocate(_Alloc& __a, size_type __n)
;
template<typename _Tp, typename... _Args>
static auto construct(_Alloc& __a, _Tp* __p, _Args&&... __args)
^ permalink raw reply [flat|nested] only message in thread
only message in thread, other threads:[~2020-04-14 6:39 UTC | newest]
Thread overview: (only message) (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-04-14 6:39 [gcc(refs/users/marxin/heads/PR94314-fix-new-delete-pair-deletion-part-3)] c++: lambdas with internal linkage are different to no-linkage [PR94426] Martin Liska
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).