This patch fixes a long-standing bug in reshape_init_r. Since r209314
we implement DR 1467 which handles list-initialization with a single
initializer of the same type as the target. In this test this causes
a crash in reshape_init_r when we're processing a constructor that has
undergone the DR 1467 transformation.
Take e.g. the
foo({{1, {H{k}}}});
line in the attached test. {H{k}} initializes the field b of H in I.
H{k} is a functional cast, so has TREE_HAS_CONSTRUCTOR set, so is
COMPOUND_LITERAL_P. We perform the DR 1467 transformation and turn
{H{k}} into H{k}. Then we attempt to reshape H{k} again and since
first_initializer_p is null and it's COMPOUND_LITERAL_P, we go here:
else if (COMPOUND_LITERAL_P (stripped_init))
gcc_assert (!BRACE_ENCLOSED_INITIALIZER_P (stripped_init));
then complain about the missing braces, go to reshape_init_class and ICE
on
gcc_checking_assert (d->cur->index
== get_class_binding (type, id));
because due to the missing { } we're looking for 'b' in H, but that's
not found.
So we have to be prepared to handle an initializer whose outer braces
have been removed due to DR 1467.
Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk and 10?
gcc/cp/ChangeLog:
PR c++/95164
* decl.c (list_init_from_same_type_p): New function.
(reshape_init_r): Call it. When we've found a missing set of braces,
but list_init_from_same_type_p is true, don't reshape again.
gcc/testsuite/ChangeLog:
PR c++/95164
* g++.dg/cpp0x/initlist123.C: New test.
---
gcc/cp/decl.c | 43 +++++++++++++++++++-----
gcc/testsuite/g++.dg/cpp0x/initlist123.C | 39 +++++++++++++++++++++
2 files changed, 74 insertions(+), 8 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/cpp0x/initlist123.C
diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index 31d68745844..a07d52cdf5b 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -6350,6 +6350,21 @@ has_designator_problem (reshape_iter *d, tsubst_flags_t
complain)
return false;
}
+/* Handle [dcl.init.list]p3.2: Return true if we should elide braces when we're
+ initializing an object of class type (or, as an extension, vector type) by
+ list-initialization with a single initializer of the same type as the
target.
+
+ TYPE is the type of the target, INIT_TYPE is the type of the element of the
+ initializer list, and D is the iterator within the CONSTRUCTOR. */
+
+static bool
+list_init_from_same_type_p (reshape_iter *d, tree type, tree init_type)
+{
+ return (cxx_dialect >= cxx11 && (CLASS_TYPE_P (type) || VECTOR_TYPE_P (type))
+ && d->end - d->cur == 1
+ && reference_related_p (type, init_type));
+}
+
/* Subroutine of reshape_init, which processes a single initializer (part of
a CONSTRUCTOR). TYPE is the type of the variable being initialized, D is the
iterator within the CONSTRUCTOR which points to the initializer to process.
@@ -6445,13 +6460,13 @@ reshape_init_r (tree type, reshape_iter *d, tree
first_initializer_p,
return init;
}
- /* "If T is a class type and the initializer list has a single element of
- type cv U, where U is T or a class derived from T, the object is
- initialized from that element." Even if T is an aggregate. */
- if (cxx_dialect >= cxx11 && (CLASS_TYPE_P (type) || VECTOR_TYPE_P (type))
- && first_initializer_p
- && d->end - d->cur == 1
- && reference_related_p (type, TREE_TYPE (init)))
+ /* [dcl.init.list]p3.2: "If T is an aggregate class and the initializer list
+ has a single element of type cv U, where U is T or a class derived from T,
+ the object is initialized from that element (by copy-initialization for
+ copy-list-initialization, or by direct-initialization for
+ direct-list-initialization)." */
+ if (first_initializer_p
+ && list_init_from_same_type_p (d, type, TREE_TYPE (init)))
{
d->cur++;
return init;
@@ -6531,7 +6546,19 @@ reshape_init_r (tree type, reshape_iter *d, tree
first_initializer_p,
/* For a nested compound literal, proceed to specialized routines,
to handle initialization of arrays and similar. */
else if (COMPOUND_LITERAL_P (stripped_init))
- gcc_assert (!BRACE_ENCLOSED_INITIALIZER_P (stripped_init));
+ {
+ gcc_assert (!BRACE_ENCLOSED_INITIALIZER_P (stripped_init));
+ /* If we previously elided the braces around the single element
+ of an initializer list when initializing an object of the same
+ class type, don't report missing braces or reshape again. In
+ this case the braces had been enclosing a compound literal or
+ functional cast with aggregate, e.g. {S{}} -> S{}. */
+ if (list_init_from_same_type_p (d, type, init_type))
+ {
+ ++d->cur;
+ return init;
+ }
+ }
/* A CONSTRUCTOR of the target's type is a previously
digested initializer. */
else if (same_type_ignoring_top_level_qualifiers_p (type, init_type))
diff --git a/gcc/testsuite/g++.dg/cpp0x/initlist123.C
b/gcc/testsuite/g++.dg/cpp0x/initlist123.C
new file mode 100644
index 00000000000..29f037f07ef
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/initlist123.C
@@ -0,0 +1,39 @@
+// PR c++/95164
+// { dg-do compile { target c++11 } }
+// { dg-options "-Wmissing-braces" }
+
+struct H {
+ int a;
+};
+
+struct X : H { };
+
+struct I {
+ int c;
+ H b;
+};
+struct E { I d; };
+void foo(E);
+
+template<int N>
+void fn ()
+{
+ int a = 42;
+ int &k = a;
+
+ foo({1, {H{k}}}); // { dg-warning "missing braces around initializer for
.I." }
+ foo({1, {X{k}}}); // { dg-warning "missing braces around initializer for
.I." }
+
+ foo({{1, {k}}});
+ foo({{1, {N}}});
+
+ foo({{1, H{k}}});
+ foo({{1, H{N}}});
+ foo({{1, X{k}}});
+ foo({{1, X{N}}});
+
+ foo({{1, {H{k}}}});
+ foo({{1, {H{N}}}});
+ foo({{1, {X{k}}}});
+ foo({{1, {X{N}}}});
+}
base-commit: f923c40f9baba19e58f65afa7e5572f08cee93ff
--
2.26.2
