On 2/23/23 18:51, Marek Polacek wrote:
Since r11-557, cp_finish_decl can call check_initializer even in
a template for a constexpr initializer. That ultimately leads to
convert_for_assignment and check_address_or_pointer_of_packed_member,
where we crash, because it doesn't expect that the CALL_EXPR is
a function object. Q has a constexpr operator(), but since we're
in a template, q(0) is a CALL_EXPR whose CALL_EXPR_FN is just
a VAR_DECL; it hasn't been converted to Q::operator<int>(&q, 0) yet.
I propose to robustify check_address_or_pointer_of_packed_member.
var-templ74.C has an XFAIL, subject to 107939.
I noticed that our -Waddress-of-packed-member tests weren't testing
member functions, added thus. (I was tempted to check
FUNCTION_POINTER_TYPE_P but that doesn't include METHOD_TYPE.)
Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk/12?
OK.
PR c++/107938
gcc/c-family/ChangeLog:
* c-warn.cc (check_address_or_pointer_of_packed_member): Check
POINTER_TYPE_P.
gcc/testsuite/ChangeLog:
* g++.dg/cpp1y/var-templ73.C: New test.
* g++.dg/cpp1y/var-templ74.C: New test.
* g++.dg/warn/Waddress-of-packed-member3.C: New test.
---
gcc/c-family/c-warn.cc | 4 ++++
gcc/testsuite/g++.dg/cpp1y/var-templ73.C | 12 ++++++++++
gcc/testsuite/g++.dg/cpp1y/var-templ74.C | 19 +++++++++++++++
.../g++.dg/warn/Waddress-of-packed-member3.C | 23 +++++++++++++++++++
4 files changed, 58 insertions(+)
create mode 100644 gcc/testsuite/g++.dg/cpp1y/var-templ73.C
create mode 100644 gcc/testsuite/g++.dg/cpp1y/var-templ74.C
create mode 100644 gcc/testsuite/g++.dg/warn/Waddress-of-packed-member3.C
diff --git a/gcc/c-family/c-warn.cc b/gcc/c-family/c-warn.cc
index a6fb95b1e80..29ae1ea1dc8 100644
--- a/gcc/c-family/c-warn.cc
+++ b/gcc/c-family/c-warn.cc
@@ -3000,6 +3000,10 @@ check_address_or_pointer_of_packed_member (tree type,
tree rhs)
if (rhs == NULL_TREE)
return NULL_TREE;
rhs = TREE_TYPE (rhs); /* Pointer type. */
+ /* We could be called while processing a template and RHS could be
+ a functor. In that case it's a class, not a pointer. */
+ if (!POINTER_TYPE_P (rhs))
+ return NULL_TREE;
rhs = TREE_TYPE (rhs); /* Function type. */
rhstype = TREE_TYPE (rhs);
if (!rhstype || !POINTER_TYPE_P (rhstype))
diff --git a/gcc/testsuite/g++.dg/cpp1y/var-templ73.C
b/gcc/testsuite/g++.dg/cpp1y/var-templ73.C
new file mode 100644
index 00000000000..b76babcfa81
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/var-templ73.C
@@ -0,0 +1,12 @@
+// PR c++/107938
+// { dg-do compile { target c++14 } }
+
+struct Q {
+ int n;
+ constexpr const Q* operator()(int) const { return this; }
+};
+
+constexpr Q q{};
+
+template<int>
+constexpr const Q* p = q(0);
diff --git a/gcc/testsuite/g++.dg/cpp1y/var-templ74.C
b/gcc/testsuite/g++.dg/cpp1y/var-templ74.C
new file mode 100644
index 00000000000..4e2e800a6eb
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/var-templ74.C
@@ -0,0 +1,19 @@
+// PR c++/107938
+// { dg-do compile { target c++14 } }
+
+struct Q {
+ int n;
+ constexpr const Q* operator()(int) const { return this; }
+};
+
+extern const Q q;
+
+template<int>
+constexpr const Q* p = q(0); // { dg-bogus "not usable" "PR107939" { xfail
*-*-* } }
+
+void
+g ()
+{
+ constexpr const Q* p2 = q(0);
+ constexpr auto x = p<0>;
+}
diff --git a/gcc/testsuite/g++.dg/warn/Waddress-of-packed-member3.C
b/gcc/testsuite/g++.dg/warn/Waddress-of-packed-member3.C
new file mode 100644
index 00000000000..aeffb969c01
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/Waddress-of-packed-member3.C
@@ -0,0 +1,23 @@
+// { dg-do compile { target { ! default_packed } } }
+// Test that -Waddress-of-packed-member works with member functions.
+
+struct S {
+ char c;
+} __attribute__((packed));
+
+struct X {
+ S* memfn ();
+ static S* smemfn ();
+} x;
+
+S *foo ();
+
+S**
+f ()
+{
+ S **s;
+ s = reinterpret_cast<S**>(foo ()); // { dg-warning "converting a packed" }
+ s = reinterpret_cast<S**>(x.memfn ()); // { dg-warning "converting a packed"
}
+ s = reinterpret_cast<S**>(X::smemfn ()); // { dg-warning "converting a
packed" }
+ return s;
+}
base-commit: f33d7a88d069d169bbe76da8e5c52de17f68ca05
