From df3a1bdce7e43b6696160b068b3171b3a3bbeab1 Mon Sep 17 00:00:00 2001 From: jason Date: Fri, 23 Sep 2011 21:30:48 +0000 Subject: [PATCH] Core 234 - allow const objects with no initializer or user-provided default constructor if the defaulted constructor initializes all the subobjects. PR c++/20039 PR c++/42844 * class.c (default_init_uninitialized_part): New. * cp-tree.h: Declare it. * decl.c (check_for_uninitialized_const_var): Use it. * init.c (perform_member_init): Likewise. (build_new_1): Likewise. * method.c (walk_field_subobs): Likewise. git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@179130 138bc75d-0d04-0410-961f-82ee72b054a4 --- gcc/cp/ChangeLog | 14 +++++++++++ gcc/cp/class.c | 34 ++++++++++++++++++++++++++ gcc/cp/cp-tree.h | 1 + gcc/cp/decl.c | 11 ++++++--- gcc/cp/init.c | 4 +-- gcc/cp/method.c | 3 +-- gcc/testsuite/ChangeLog | 10 ++++++++ gcc/testsuite/g++.dg/cpp0x/constexpr-object1.C | 2 +- gcc/testsuite/g++.dg/cpp0x/defaulted2.C | 3 ++- gcc/testsuite/g++.dg/cpp0x/pr42844-2.C | 4 +++ gcc/testsuite/g++.dg/init/const8.C | 11 +++++++++ gcc/testsuite/g++.dg/init/pr20039.C | 1 + gcc/testsuite/g++.dg/init/pr42844.C | 14 +++++------ 13 files changed, 95 insertions(+), 17 deletions(-) create mode 100644 gcc/testsuite/g++.dg/init/const8.C diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog index 9e655cc26bb..4c0edf6cc0a 100644 --- a/gcc/cp/ChangeLog +++ b/gcc/cp/ChangeLog @@ -1,3 +1,17 @@ +2011-09-23 Jason Merrill + + Core 234 - allow const objects with no initializer or + user-provided default constructor if the defaulted constructor + initializes all the subobjects. + PR c++/20039 + PR c++/42844 + * class.c (default_init_uninitialized_part): New. + * cp-tree.h: Declare it. + * decl.c (check_for_uninitialized_const_var): Use it. + * init.c (perform_member_init): Likewise. + (build_new_1): Likewise. + * method.c (walk_field_subobs): Likewise. + 2011-09-23 Paolo Carlini PR c++/50258 diff --git a/gcc/cp/class.c b/gcc/cp/class.c index e3984168032..18875268808 100644 --- a/gcc/cp/class.c +++ b/gcc/cp/class.c @@ -4356,6 +4356,40 @@ type_has_user_provided_default_constructor (tree t) return false; } +/* If default-initialization leaves part of TYPE uninitialized, returns + a DECL for the field or TYPE itself (DR 253). */ + +tree +default_init_uninitialized_part (tree type) +{ + tree t, r, binfo; + int i; + + type = strip_array_types (type); + if (!CLASS_TYPE_P (type)) + return type; + if (type_has_user_provided_default_constructor (type)) + return NULL_TREE; + for (binfo = TYPE_BINFO (type), i = 0; + BINFO_BASE_ITERATE (binfo, i, t); ++i) + { + r = default_init_uninitialized_part (BINFO_TYPE (t)); + if (r) + return r; + } + for (t = TYPE_FIELDS (type); t; t = DECL_CHAIN (t)) + if (TREE_CODE (t) == FIELD_DECL + && !DECL_ARTIFICIAL (t) + && !DECL_INITIAL (t)) + { + r = default_init_uninitialized_part (TREE_TYPE (t)); + if (r) + return DECL_P (r) ? r : t; + } + + return NULL_TREE; +} + /* Returns true iff for class T, a trivial synthesized default constructor would be constexpr. */ diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h index bcfc3b3be0f..573c166a08b 100644 --- a/gcc/cp/cp-tree.h +++ b/gcc/cp/cp-tree.h @@ -4838,6 +4838,7 @@ extern tree in_class_defaulted_default_constructor (tree); extern bool user_provided_p (tree); extern bool type_has_user_provided_constructor (tree); extern bool type_has_user_provided_default_constructor (tree); +extern tree default_init_uninitialized_part (tree); extern bool trivial_default_constructor_is_constexpr (tree); extern bool type_has_constexpr_default_constructor (tree); extern bool type_has_virtual_destructor (tree); diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c index 709deca9259..495d8a059d7 100644 --- a/gcc/cp/decl.c +++ b/gcc/cp/decl.c @@ -4899,15 +4899,16 @@ check_for_uninitialized_const_var (tree decl) if (TREE_CODE (decl) == VAR_DECL && TREE_CODE (type) != REFERENCE_TYPE && CP_TYPE_CONST_P (type) - && (!TYPE_NEEDS_CONSTRUCTING (type) - || !type_has_user_provided_default_constructor (type)) && !DECL_INITIAL (decl)) { + tree field = default_init_uninitialized_part (type); + if (!field) + return; + permerror (DECL_SOURCE_LOCATION (decl), "uninitialized const %qD", decl); - if (CLASS_TYPE_P (type) - && !type_has_user_provided_default_constructor (type)) + if (CLASS_TYPE_P (type)) { tree defaulted_ctor; @@ -4918,6 +4919,8 @@ check_for_uninitialized_const_var (tree decl) inform (DECL_SOURCE_LOCATION (defaulted_ctor), "constructor is not user-provided because it is " "explicitly defaulted in the class body"); + inform (0, "and the implicitly-defined constructor does not " + "initialize %q+#D", field); } } } diff --git a/gcc/cp/init.c b/gcc/cp/init.c index ff1884b361d..68d4e681214 100644 --- a/gcc/cp/init.c +++ b/gcc/cp/init.c @@ -579,7 +579,7 @@ perform_member_init (tree member, tree init) flags |= LOOKUP_DEFAULTED; if (CP_TYPE_CONST_P (type) && init == NULL_TREE - && !type_has_user_provided_default_constructor (type)) + && default_init_uninitialized_part (type)) /* TYPE_NEEDS_CONSTRUCTING can be set just because we have a vtable; still give this diagnostic. */ permerror (DECL_SOURCE_LOCATION (current_function_decl), @@ -2088,7 +2088,7 @@ build_new_1 (VEC(tree,gc) **placement, tree type, tree nelts, } if (CP_TYPE_CONST_P (elt_type) && *init == NULL - && !type_has_user_provided_default_constructor (elt_type)) + && default_init_uninitialized_part (elt_type)) { if (complain & tf_error) error ("uninitialized const in % of %q#T", elt_type); diff --git a/gcc/cp/method.c b/gcc/cp/method.c index 5b24f8f0285..757e711dd2c 100644 --- a/gcc/cp/method.c +++ b/gcc/cp/method.c @@ -1015,8 +1015,7 @@ walk_field_subobs (tree fields, tree fnname, special_function_kind sfk, { bool bad = true; if (CP_TYPE_CONST_P (mem_type) - && (!CLASS_TYPE_P (mem_type) - || !type_has_user_provided_default_constructor (mem_type))) + && default_init_uninitialized_part (mem_type)) { if (msg) error ("uninitialized non-static const member %q#D", diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 756a4dea036..208add9d6db 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,13 @@ +2011-09-23 Jason Merrill + + Core 234 + * g++.dg/init/const8.C: New. + * g++.dg/cpp0x/constexpr-object1.C: Add a data member. + * g++.dg/cpp0x/defaulted2.C: Likewise. + * g++.dg/cpp0x/pr42844-2.C: Likewise. + * g++.dg/init/pr20039.C: Likewise. + * g++.dg/init/pr42844.C: Likewise. + 2011-09-23 Jan Hubicka * gcc.dg/ipa/inline-1.c: new testcase. diff --git a/gcc/testsuite/g++.dg/cpp0x/constexpr-object1.C b/gcc/testsuite/g++.dg/cpp0x/constexpr-object1.C index 3af85095fa5..4ff398bf1f0 100644 --- a/gcc/testsuite/g++.dg/cpp0x/constexpr-object1.C +++ b/gcc/testsuite/g++.dg/cpp0x/constexpr-object1.C @@ -7,7 +7,7 @@ // p 1 constexpr specifier // objects, static const data -struct A1 { }; // { dg-message "no user-provided default constructor" } +struct A1 { int i; }; // { dg-message "no user-provided default constructor" } constexpr int i1 = 1024; constexpr A1 a1 = A1(); diff --git a/gcc/testsuite/g++.dg/cpp0x/defaulted2.C b/gcc/testsuite/g++.dg/cpp0x/defaulted2.C index 1f400f4fad0..e3aac8f1a9f 100644 --- a/gcc/testsuite/g++.dg/cpp0x/defaulted2.C +++ b/gcc/testsuite/g++.dg/cpp0x/defaulted2.C @@ -17,7 +17,8 @@ void g() = delete; // { dg-error "redefinition" } struct B // { dg-message "user-provided default constructor" } { - B() = default; // { dg-message "not user-provided" } + int i; + B() = default; // { dg-message "not user-provided" } }; const B b; // { dg-error "uninitialized const" } diff --git a/gcc/testsuite/g++.dg/cpp0x/pr42844-2.C b/gcc/testsuite/g++.dg/cpp0x/pr42844-2.C index 5af4ff217f3..4425aacf627 100644 --- a/gcc/testsuite/g++.dg/cpp0x/pr42844-2.C +++ b/gcc/testsuite/g++.dg/cpp0x/pr42844-2.C @@ -4,6 +4,7 @@ struct A // { dg-message "user-provided default constructor" } { + int i; A() = default; // { dg-message "not user-provided" } }; @@ -14,17 +15,20 @@ struct Base struct Derived : Base // { dg-message "user-provided default constructor" } { + int i; Derived() = default; // { dg-message "not user-provided" } }; struct Derived2 : Base // { dg-message "user-provided default constructor" } { + int i; Derived2() = default; // { dg-message "not user-provided" } Derived2( Derived2 const& ) = default; }; struct Derived3 : Base // { dg-message "user-provided default constructor" } { + int i; Derived3( Derived3 const& ) = default; Derived3() = default; // { dg-message "not user-provided" } }; diff --git a/gcc/testsuite/g++.dg/init/const8.C b/gcc/testsuite/g++.dg/init/const8.C new file mode 100644 index 00000000000..4eb293d654c --- /dev/null +++ b/gcc/testsuite/g++.dg/init/const8.C @@ -0,0 +1,11 @@ +// DR 234 - it should be OK to leave off the initializer of a const +// variable if the default constructor fully initializes the object. + +struct A { }; +const A a; + +struct B { A a; }; +const B b; + +struct C { virtual void f(); }; +const C c; diff --git a/gcc/testsuite/g++.dg/init/pr20039.C b/gcc/testsuite/g++.dg/init/pr20039.C index 9b0c12d6ea3..aaac8bd4e3c 100644 --- a/gcc/testsuite/g++.dg/init/pr20039.C +++ b/gcc/testsuite/g++.dg/init/pr20039.C @@ -10,6 +10,7 @@ struct M struct X { M m; + int i; }; int mymain() diff --git a/gcc/testsuite/g++.dg/init/pr42844.C b/gcc/testsuite/g++.dg/init/pr42844.C index 7b423ccb64b..299a30a91d2 100644 --- a/gcc/testsuite/g++.dg/init/pr42844.C +++ b/gcc/testsuite/g++.dg/init/pr42844.C @@ -6,19 +6,19 @@ struct A A(){} }; -struct B : A {}; // { dg-message "user-provided default constructor" } +struct B : A { int i; }; // { dg-message "user-provided default constructor" } -struct C : A {}; // { dg-message "user-provided default constructor" } +struct C : A { int i; }; // { dg-message "user-provided default constructor" } struct D : B { D() {} }; -struct E {}; // { dg-message "user-provided default constructor" } +struct E { int i; }; // { dg-message "user-provided default constructor" } template -struct F : A {}; // { dg-message "user-provided default constructor" } +struct F : A { T t; }; // { dg-message "user-provided default constructor" } template -struct G {}; // { dg-message "user-provided default constructor" } +struct G { T t; }; // { dg-message "user-provided default constructor" } void f () { @@ -41,9 +41,9 @@ void f () extern G const gext; } -struct H {}; // { dg-message "user-provided default constructor" } +struct H { int i; }; // { dg-message "user-provided default constructor" } -struct I : A {}; // { dg-message "user-provided default constructor" } +struct I : A { int i; }; // { dg-message "user-provided default constructor" } template void g () -- 2.11.0