From 753b4679bc46f6806cf45d9afc3783c6d3b63589 Mon Sep 17 00:00:00 2001 From: Marek Polacek Date: Wed, 26 Aug 2020 08:27:33 -0400 Subject: [PATCH] c++: Fix P0960 in member init list and array [PR92812] This patch nails down the remaining P0960 case in PR92812: struct A { int ar[2]; A(): ar(1, 2) {} // doesn't work without this patch }; Note that when the target object is not of array type, this already works: struct S { int x, y; }; struct A { S s; A(): s(1, 2) { } // OK in C++20 }; because build_new_method_call_1 takes care of the P0960 magic. It proved to be quite hairy. When the ()-list has more than one element, we can always create a CONSTRUCTOR, because the code was previously invalid. But when the ()-list has just one element, it gets all kinds of difficult. As usual, we have to handle a("foo") so as not to wrap the STRING_CST in a CONSTRUCTOR. Always turning x(e) into x{e} would run into trouble as in c++/93790. Another issue was what to do about x({e}): previously, this would trigger "list-initializer for non-class type must not be parenthesized". I figured I'd make this work in C++20, so that given struct S { int x, y; }; you can do S a[2]; [...] A(): a({1, 2}) // initialize a[0] with {1, 2} and a[1] with {} It also turned out that, as an extension, we support compound literals: F (): m((S[1]) { 1, 2 }) so this has to keep working as before. Moreover, make sure not to trigger in compiler-generated code, like =default, where array assignment is allowed. I've factored out a function that turns a TREE_LIST into a CONSTRUCTOR to simplify handling of P0960. paren-init35.C also tests this with vector types. gcc/cp/ChangeLog: PR c++/92812 * cp-tree.h (do_aggregate_paren_init): Declare. * decl.c (do_aggregate_paren_init): New. (grok_reference_init): Use it. (check_initializer): Likewise. * init.c (perform_member_init): Handle initializing an array from a ()-list. Use do_aggregate_paren_init. gcc/testsuite/ChangeLog: PR c++/92812 * g++.dg/cpp0x/constexpr-array23.C: Adjust dg-error. * g++.dg/cpp0x/initlist69.C: Likewise. * g++.dg/diagnostic/mem-init1.C: Likewise. * g++.dg/init/array28.C: Likewise. * g++.dg/cpp2a/paren-init33.C: New test. * g++.dg/cpp2a/paren-init34.C: New test. * g++.dg/cpp2a/paren-init35.C: New test. * g++.old-deja/g++.brendan/crash60.C: Adjust dg-error. * g++.old-deja/g++.law/init10.C: Likewise. * g++.old-deja/g++.other/array3.C: Likewise. --- gcc/cp/cp-tree.h | 1 + gcc/cp/decl.c | 62 +++++---- gcc/cp/init.c | 26 +++- .../g++.dg/cpp0x/constexpr-array23.C | 6 +- gcc/testsuite/g++.dg/cpp0x/initlist69.C | 4 +- gcc/testsuite/g++.dg/cpp2a/paren-init33.C | 128 ++++++++++++++++++ gcc/testsuite/g++.dg/cpp2a/paren-init34.C | 25 ++++ gcc/testsuite/g++.dg/cpp2a/paren-init35.C | 21 +++ gcc/testsuite/g++.dg/diagnostic/mem-init1.C | 4 +- gcc/testsuite/g++.dg/init/array28.C | 2 +- .../g++.old-deja/g++.brendan/crash60.C | 2 +- gcc/testsuite/g++.old-deja/g++.law/init10.C | 2 +- gcc/testsuite/g++.old-deja/g++.other/array3.C | 3 +- 13 files changed, 239 insertions(+), 47 deletions(-) create mode 100644 gcc/testsuite/g++.dg/cpp2a/paren-init33.C create mode 100644 gcc/testsuite/g++.dg/cpp2a/paren-init34.C create mode 100644 gcc/testsuite/g++.dg/cpp2a/paren-init35.C diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h index 2b7c9b9913a..708de83eb46 100644 --- a/gcc/cp/cp-tree.h +++ b/gcc/cp/cp-tree.h @@ -6582,6 +6582,7 @@ extern bool check_array_designated_initializer (constructor_elt *, extern bool check_for_uninitialized_const_var (tree, bool, tsubst_flags_t); extern tree build_explicit_specifier (tree, tsubst_flags_t); extern void do_push_parm_decls (tree, tree, tree *); +extern tree do_aggregate_paren_init (tree, tree); /* in decl2.c */ extern void record_mangling (tree, bool); diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c index 4c84f2d0a9b..31d68745844 100644 --- a/gcc/cp/decl.c +++ b/gcc/cp/decl.c @@ -5557,6 +5557,37 @@ start_decl_1 (tree decl, bool initialized) maybe_push_cleanup_level (type); } +/* Given a parenthesized list of values INIT, create a CONSTRUCTOR to handle + C++20 P0960. TYPE is the type of the object we're initializing. */ + +tree +do_aggregate_paren_init (tree init, tree type) +{ + tree val = TREE_VALUE (init); + + if (TREE_CHAIN (init) == NULL_TREE) + { + /* If the list has a single element and it's a string literal, + then it's the initializer for the array as a whole. */ + if (TREE_CODE (type) == ARRAY_TYPE + && char_type_p (TYPE_MAIN_VARIANT (TREE_TYPE (type))) + && TREE_CODE (tree_strip_any_location_wrapper (val)) + == STRING_CST) + return val; + /* Handle non-standard extensions like compound literals. This also + prevents triggering aggregate parenthesized-initialization in + compiler-generated code for =default. */ + else if (same_type_ignoring_top_level_qualifiers_p (type, + TREE_TYPE (val))) + return val; + } + + init = build_constructor_from_list (init_list_type_node, init); + CONSTRUCTOR_IS_DIRECT_INIT (init) = true; + CONSTRUCTOR_IS_PAREN_INIT (init) = true; + return init; +} + /* Handle initialization of references. DECL, TYPE, and INIT have the same meaning as in cp_finish_decl. *CLEANUP must be NULL on entry, but will be set to a new CLEANUP_STMT if a temporary is created @@ -5604,11 +5635,7 @@ grok_reference_init (tree decl, tree type, tree init, int flags) /* If the list had more than one element, the code is ill-formed pre-C++20, so we can build a constructor right away. */ else - { - init = build_constructor_from_list (init_list_type_node, init); - CONSTRUCTOR_IS_DIRECT_INIT (init) = true; - CONSTRUCTOR_IS_PAREN_INIT (init) = true; - } + init = do_aggregate_paren_init (init, ttype); } else init = build_x_compound_expr_from_list (init, ELK_INIT, @@ -6794,30 +6821,7 @@ check_initializer (tree decl, tree init, int flags, vec **cleanups) && TREE_CODE (type) == ARRAY_TYPE && !DECL_DECOMPOSITION_P (decl) && (cxx_dialect >= cxx20)) - { - /* [dcl.init.string] "An array of ordinary character type [...] - can be initialized by an ordinary string literal [...] by an - appropriately-typed string literal enclosed in braces" only - talks about braces, but GCC has always accepted - - char a[]("foobar"); - - so we continue to do so. */ - tree val = TREE_VALUE (init); - if (TREE_CHAIN (init) == NULL_TREE - && char_type_p (TYPE_MAIN_VARIANT (TREE_TYPE (type))) - && TREE_CODE (tree_strip_any_location_wrapper (val)) - == STRING_CST) - /* If the list has a single element and it's a string literal, - then it's the initializer for the array as a whole. */ - init = val; - else - { - init = build_constructor_from_list (init_list_type_node, init); - CONSTRUCTOR_IS_DIRECT_INIT (init) = true; - CONSTRUCTOR_IS_PAREN_INIT (init) = true; - } - } + init = do_aggregate_paren_init (init, type); else if (TREE_CODE (init) == TREE_LIST && TREE_TYPE (init) != unknown_type_node && !MAYBE_CLASS_TYPE_P (type)) diff --git a/gcc/cp/init.c b/gcc/cp/init.c index d4540db3605..3268ae4ad3f 100644 --- a/gcc/cp/init.c +++ b/gcc/cp/init.c @@ -809,13 +809,25 @@ perform_member_init (tree member, tree init) return; } - if (init && TREE_CODE (init) == TREE_LIST - && (DIRECT_LIST_INIT_P (TREE_VALUE (init)) - /* FIXME C++20 parenthesized aggregate init (PR 92812). */ - || !(/* cxx_dialect >= cxx20 ? CP_AGGREGATE_TYPE_P (type) */ - /* : */CLASS_TYPE_P (type)))) - init = build_x_compound_expr_from_list (init, ELK_MEM_INIT, - tf_warning_or_error); + if (init && TREE_CODE (init) == TREE_LIST) + { + /* A(): a{e} */ + if (DIRECT_LIST_INIT_P (TREE_VALUE (init))) + init = build_x_compound_expr_from_list (init, ELK_MEM_INIT, + tf_warning_or_error); + /* We are trying to initialize an array from a ()-list. If we + should attempt to do so, conjure up a CONSTRUCTOR. */ + else if (TREE_CODE (type) == ARRAY_TYPE + /* P0960 is a C++20 feature. */ + && cxx_dialect >= cxx20) + init = do_aggregate_paren_init (init, type); + else if (!CLASS_TYPE_P (type)) + init = build_x_compound_expr_from_list (init, ELK_MEM_INIT, + tf_warning_or_error); + /* If we're initializing a class from a ()-list, leave the TREE_LIST + alone: we might call an appropriate constructor, or (in C++20) + do aggregate-initialization. */ + } if (init == void_type_node) { diff --git a/gcc/testsuite/g++.dg/cpp0x/constexpr-array23.C b/gcc/testsuite/g++.dg/cpp0x/constexpr-array23.C index 1323271a0a5..1829fa7a653 100644 --- a/gcc/testsuite/g++.dg/cpp0x/constexpr-array23.C +++ b/gcc/testsuite/g++.dg/cpp0x/constexpr-array23.C @@ -9,9 +9,9 @@ struct A }; struct B -{ // This should really be target { ! c++2a } - typedef A W[4]; // { dg-error "paren" "" { target *-*-* } .+1 } - constexpr B () : w ({ A::z, A::z, A::z, A::z }) {} // { dg-error "constant" } +{ + typedef A W[4]; // { dg-error "paren" "" { target { ! c++20 } } .+1 } + constexpr B () : w ({ A::z, A::z, A::z, A::z }) {} // { dg-error "constant|could not convert" } W w; }; diff --git a/gcc/testsuite/g++.dg/cpp0x/initlist69.C b/gcc/testsuite/g++.dg/cpp0x/initlist69.C index 7995f595a47..893a4e92cd3 100644 --- a/gcc/testsuite/g++.dg/cpp0x/initlist69.C +++ b/gcc/testsuite/g++.dg/cpp0x/initlist69.C @@ -6,14 +6,14 @@ struct ca { T elem[1]; ca(const T (&s)[1]): elem{{s}} { } // { dg-error "invalid" } - ca(const T (&s)[1],int): elem({{s}}) { } // { dg-error "paren|invalid" } + ca(const T (&s)[1],int): elem({{s}}) { } // { dg-error "paren|invalid|too many" } ca(const T (&s)[1],char): elem(s) { } // { dg-error "array" } ca(const T (&s)[1],double): elem{s} { } // { dg-error "invalid" } ca(const T &v): elem{{v}} { } // OK ca(const T &v,int): elem{{{v}}} { } // { dg-error "braces" } ca(const T &v,char): elem{v} { } // OK - ca(const T &v,double): elem({v}) { } // { dg-error "paren" } + ca(const T &v,double): elem({v}) { } // { dg-error "paren" "" { target { ! c++20 } } } }; int main() { diff --git a/gcc/testsuite/g++.dg/cpp2a/paren-init33.C b/gcc/testsuite/g++.dg/cpp2a/paren-init33.C new file mode 100644 index 00000000000..43f323e8f14 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp2a/paren-init33.C @@ -0,0 +1,128 @@ +// PR c++/92812 +// { dg-do run { target c++20 } } +// { dg-options "-Wall -Wextra" } +// Initializing arrays in a member init list using ()-init, valid cases. + +#define assert(X) do { if (!(X)) __builtin_abort(); } while(0) + +struct S { int x, y; }; +struct N { int x, y; N(int, int); }; + +static S s{10, 11}; + +struct A { + S s1; + S s2; + S a1[2]; + S a2[2]; + S a3[2]; + S a4[2]; + S a5[2]; + S a6[2]; + A() : s1(1, 2), + s2(1), // { dg-warning "missing initializer for member" } + a1({1}), // { dg-warning "missing initializer for member" } + a2({1, 2}), + a3({}, {}), + a4(), + a5(s), + a6(s, s) + { } +}; + +struct C { + int a1[2]; + int a2[2]; + int a3[2]; + int a4[2]; + int a5[2]; + C() : a1(1), + a2(1, 2), + a3({1}), + a4({}, {}), + a5() + { } +}; + +struct D { + N n; + // Not an aggregate, should work pre-C++20 too. + D() : n(1, 2) { } +}; + +struct E { + char a1[4]; + char a2[4]; + E() : a1("ab"), + a2("abc") + { } +}; + +// Compound literal. +struct F { + F (); + S m[1]; +}; + +F::F () : m(__extension__(S[1]) { 1, 2 }) +{ +} + +struct B { int i; }; +struct Der : B { }; +Der d; +struct G { + B b1[1]; + B b2[2]; + G(): b1(d), + b2(d, d) + { } +}; + +// Variation of c++/93790. +struct Empty { }; +struct Empty_refwrap { + Empty& r; + Empty_refwrap(Empty &e) : r(e) { } + operator Empty&() { return r; } +}; + +Empty empty; +Empty_refwrap empty_refwrap(empty); + +struct H { + Empty &e; + // Turning this into {empty_refwrap} would break things. + H() : e(empty_refwrap) { } +}; + +int +main () +{ + A a; + assert (a.s1.x == 1 && a.s1.y == 2); + assert (a.s2.x == 1 && a.s2.y == 0); + assert (a.a1[0].x == 1 && a.a1[0].y == 0 + && a.a1[1].x == 0 && a.a1[1].y == 0); + assert (a.a2[0].x == 1 && a.a2[0].y == 2 + && a.a2[1].x == 0 && a.a2[1].y == 0); + assert (a.a3[0].x == 0 && a.a3[0].y == 0 + && a.a3[1].x == 0 && a.a3[1].y == 0); + assert (a.a4[0].x == 0 && a.a4[0].y == 0 + && a.a4[1].x == 0 && a.a4[1].y == 0); + assert (a.a5[0].x == 10 && a.a5[0].y == 11 + && a.a5[1].x == 0 && a.a5[1].y == 0); + assert (a.a6[0].x == 10 && a.a6[0].y == 11 + && a.a6[1].x == 10 && a.a6[1].y == 11); + + C c; + assert (c.a1[0] == 1 && c.a1[1] == 0); + assert (c.a2[0] == 1 && c.a2[1] == 2); + assert (c.a3[0] == 1 && c.a3[1] == 0); + assert (c.a4[0] == 0 && c.a4[1] == 0); + assert (c.a5[0] == 0 && c.a5[1] == 0); + + E e; + assert (__builtin_strcmp (e.a1, "ab") == 0 + && __builtin_strcmp (e.a2, "abc") == 0); +} diff --git a/gcc/testsuite/g++.dg/cpp2a/paren-init34.C b/gcc/testsuite/g++.dg/cpp2a/paren-init34.C new file mode 100644 index 00000000000..24942764cb7 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp2a/paren-init34.C @@ -0,0 +1,25 @@ +// PR c++/92812 +// { dg-do compile { target c++20 } } +// Initializing arrays in a member init list using ()-init, invalid cases. + +struct S { int x, y; }; +struct N { int x, y; N(int, int); }; + +struct A { + N a[2]; + A() : a(1, 2) { } // { dg-error "could not convert" } +}; + +struct B { + S a[2]; + B() : a(1) // { dg-error "could not convert" } + { } +}; + +// Copy-initialization does not consider explicit ctors. +struct E { explicit E(int); }; + +struct C { + E a[2]; + C() : a(4, 5) { } // { dg-error "could not convert" } +}; diff --git a/gcc/testsuite/g++.dg/cpp2a/paren-init35.C b/gcc/testsuite/g++.dg/cpp2a/paren-init35.C new file mode 100644 index 00000000000..4f1892742c4 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp2a/paren-init35.C @@ -0,0 +1,21 @@ +// PR c++/92812 +// { dg-do compile { target c++20 } } +// { dg-additional-options "-Wno-psabi" } +// Paren-init in a member init list with vector types. + +typedef float __m128 __attribute__ ((__vector_size__ (16), __may_alias__)); + +__m128 m; +__m128 g(m); +__m128 ag[](m, m, m); +__m128 ag2[]({}, {}, {}); + +struct A { + __m128 a1; + __m128 a2[2]; + __m128 a3[2]; + A() : a1(m), + a2(m, m), + a3({}, m) + { } +}; diff --git a/gcc/testsuite/g++.dg/diagnostic/mem-init1.C b/gcc/testsuite/g++.dg/diagnostic/mem-init1.C index b749c72cd8b..8ea5264b0e0 100644 --- a/gcc/testsuite/g++.dg/diagnostic/mem-init1.C +++ b/gcc/testsuite/g++.dg/diagnostic/mem-init1.C @@ -4,7 +4,7 @@ struct A { A() : a() // { dg-error "reference type" } - , b(1) // { dg-error "incompatible" } + , b(1) // { dg-error "incompatible" "" { target { ! c++20 } } } , c(0) // { dg-bogus "" } {} @@ -17,7 +17,7 @@ template struct B { B() : a() // { dg-error "reference type" } - , b(1) // { dg-error "incompatible" } + , b(1) // { dg-error "incompatible" "" { target { ! c++20 } } } , c(0) // { dg-bogus "" } {} diff --git a/gcc/testsuite/g++.dg/init/array28.C b/gcc/testsuite/g++.dg/init/array28.C index 9869354279d..a75c36215f9 100644 --- a/gcc/testsuite/g++.dg/init/array28.C +++ b/gcc/testsuite/g++.dg/init/array28.C @@ -2,6 +2,6 @@ struct Foo { explicit Foo(int) { } }; struct Goo { - Goo() : x(Foo(4), Foo(5)) { } // { dg-error "" } + Goo() : x(Foo(4), Foo(5)) { } // { dg-error "" "" { target { ! c++20 } } } Foo x[2]; }; diff --git a/gcc/testsuite/g++.old-deja/g++.brendan/crash60.C b/gcc/testsuite/g++.old-deja/g++.brendan/crash60.C index a59d72a7bf6..1f5629b5134 100644 --- a/gcc/testsuite/g++.old-deja/g++.brendan/crash60.C +++ b/gcc/testsuite/g++.old-deja/g++.brendan/crash60.C @@ -9,4 +9,4 @@ public: // Note that we mistakenly initialize the array data member as if it // was scalar -X::X () : f (0) {}// { dg-error "" } .* +X::X () : f (0) {}// { dg-error "" "" { target { ! c++20 } } } diff --git a/gcc/testsuite/g++.old-deja/g++.law/init10.C b/gcc/testsuite/g++.old-deja/g++.law/init10.C index 90e3e45d682..1a020ec730b 100644 --- a/gcc/testsuite/g++.old-deja/g++.law/init10.C +++ b/gcc/testsuite/g++.old-deja/g++.law/init10.C @@ -20,7 +20,7 @@ public: b(); }; -b::b() : three(this) // { dg-error "array" } +b::b() : three(this) // { dg-error "array|could not convert" } { } diff --git a/gcc/testsuite/g++.old-deja/g++.other/array3.C b/gcc/testsuite/g++.old-deja/g++.other/array3.C index f89090f1747..6eeeb4f3888 100644 --- a/gcc/testsuite/g++.old-deja/g++.other/array3.C +++ b/gcc/testsuite/g++.old-deja/g++.other/array3.C @@ -20,6 +20,7 @@ class B }; B::B (const A a[]) - : ary(a) // { dg-error "array" } + // { dg-error "could not convert|invalid conversion" "" { target { c++20 } } .+1 } + : ary(a) // { dg-error "array" "" { target { ! c++20 } } } { } -- 2.30.2