73a2b8dd17
This patch implements C++20 P1009, allowing code like
new double[]{1,2,3}; // array bound will be deduced
Since this proposal makes the initialization rules more consistent, it is
applied to all previous versions of C++ (thus, effectively, all the way back
to C++11).
My patch is based on Jason's patch that handled the basic case. I've
extended it to work with ()-init and also the string literal case.
Further testing revealed that to handle stuff like
new int[]{t...};
in a template, we have to consider such a NEW_EXPR type-dependent.
Obviously, we first have to expand the pack to be able to deduce the
number of elements in the array.
Curiously, while implementing this proposal, I noticed that we fail
to accept
new char[4]{"abc"};
so I've assigned 77841 to self. I think the fix will depend on the
build_new_1 hunk in this patch.
The new tree.c function build_constructor_from_vec helps us morph
a vector into a CONSTRUCTOR more efficiently.
gcc/cp/ChangeLog:
PR c++/93529
* call.c (build_new_method_call_1): Use build_constructor_from_vec
instead of build_tree_list_vec + build_constructor_from_list.
* init.c (build_new_1): Handle new char[]{"foo"}. Use
build_constructor_from_vec instead of build_tree_list_vec +
build_constructor_from_list.
(build_new): Deduce the array size in new-expression if not
present. Handle ()-init. Handle initializing an array from
a string literal.
* parser.c (cp_parser_new_type_id): Leave [] alone.
(cp_parser_direct_new_declarator): Allow [].
* pt.c (type_dependent_expression_p): In a NEW_EXPR, consider
array types whose dimension has to be deduced type-dependent.
gcc/ChangeLog:
PR c++/93529
* tree.c (build_constructor_from_vec): New.
* tree.h (build_constructor_from_vec): Declare.
gcc/testsuite/ChangeLog:
PR c++/93529
* g++.dg/cpp0x/sfinae4.C: Adjust expected result after P1009.
* g++.dg/cpp2a/new-array1.C: New test.
* g++.dg/cpp2a/new-array2.C: New test.
* g++.dg/cpp2a/new-array3.C: New test.
* g++.dg/cpp2a/new-array4.C: New test.
Co-authored-by: Jason Merrill <jason@redhat.com>
71 lines
2.1 KiB
C
71 lines
2.1 KiB
C
// PR c++/93529
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// P1009: Array size deduction in new-expressions
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// { dg-do run { target c++11 } }
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// When the array bound is deduced to 0, malloc(0) returns
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// a non-dereferenceable pointer.
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int *p0 = new int[]{};
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int *p1 = new int[]{ 1 };
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int *p2 = new int[]{ 1, 2, 3 };
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char *c1 = new char[]{"foo"};
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#if __cpp_aggregate_paren_init
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int *q0 = new int[]();
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int *q1 = new int[](1);
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int *q2 = new int[](1, 2, 3);
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char *d1 = new char[]("foo");
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char *d2 = new char[4]("foo");
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char *d3 = new char[]((("foo")));
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#endif
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struct Aggr { int a; int b; int c; };
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Aggr *a1 = new Aggr[]{};
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Aggr *a2 = new Aggr[]{ 1, 2, 3 };
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Aggr *a3 = new Aggr[]{ 1, 2, 3, 4 };
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Aggr *a4 = new Aggr[]{ { 1, 2, 3 } };
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Aggr *a5 = new Aggr[]{ { 1 }, { 6, 7 } };
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#if __cpp_designated_initializers
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Aggr *a9 = new Aggr[]{ { .a = 1, .b = 2, .c = 3 } };
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#endif
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#if __cpp_aggregate_paren_init
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Aggr *a6 = new Aggr[]();
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Aggr *a7 = new Aggr[]({ 1, 2, 3 });
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Aggr *a8 = new Aggr[]({ 1 }, { 6, 7 });
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#endif
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int
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main ()
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{
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if (p1[0] != 1 || p2[0] != 1 || p2[1] != 2 || p2[2] != 3)
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__builtin_abort ();
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if (__builtin_strcmp (c1, "foo"))
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__builtin_abort ();
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if (a2->a != 1 || a2->b != 2 || a2->c != 3)
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__builtin_abort ();
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if (a3[0].a != 1 || a3[0].b != 2 || a3[0].c != 3
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|| a3[1].a != 4 || a3[1].b != 0 || a3[1].c != 0)
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__builtin_abort ();
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if (a4->a != 1 || a4->b != 2 || a4->c != 3)
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__builtin_abort ();
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if (a5[0].a != 1 || a5[0].b != 0 || a5[0].c != 0
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|| a5[1].a != 6 || a5[1].b != 7 || a5[1].c != 0)
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__builtin_abort ();
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#if __cpp_designated_initializers
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if (a9->a != 1 || a9->b != 2 || a9->c != 3)
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__builtin_abort ();
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#endif
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#if __cpp_aggregate_paren_init
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if (q1[0] != 1)
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__builtin_abort ();
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if (q2[0] != 1 || q2[1] != 2 || q2[2] != 3)
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__builtin_abort ();
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if (__builtin_strcmp (d1, "foo") || __builtin_strcmp (d2, "foo")
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|| __builtin_strcmp (d3, "foo"))
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__builtin_abort ();
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if (a7[0].a != 1 || a7[0].b != 2 || a7[0].c != 3)
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__builtin_abort ();
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if (a8[0].a != 1 || a8[0].b != 0 || a8[0].c != 0
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|| a8[1].a != 6 || a8[1].b != 7 || a8[1].c != 0)
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__builtin_abort ();
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#endif
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}
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