Hi!
We can't call maybe_apply_pragma_weak for structured binding decls
at start_decl time, as that is too early, we don't have DECL_ASSEMBLER_NAME
computed yet for them and because we don't have the corresponding decls
around yet, we can't even compute it.
This patch defers the maybe_apply_pragma_weak call from start_decl to
cp_maybe_mangle_decomp where we just added the mangling the call needs.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2018-04-05 Jakub Jelinek <ja...@redhat.com>
PR c++/85208
* decl.c (start_decl): For DECL_DECOMPOSITION_P decls, don't call
maybe_apply_pragma_weak here...
(cp_maybe_mangle_decomp): ... but call it here instead.
* g++.dg/cpp1z/decomp42.C: New test.
--- gcc/cp/decl.c.jj 2018-04-04 21:33:20.532639396 +0200
+++ gcc/cp/decl.c 2018-04-05 13:29:39.128215719 +0200
@@ -5090,7 +5090,7 @@ start_decl (const cp_declarator *declara
}
/* If #pragma weak was used, mark the decl weak now. */
- if (!processing_template_decl)
+ if (!processing_template_decl && !DECL_DECOMPOSITION_P (decl))
maybe_apply_pragma_weak (decl);
if (TREE_CODE (decl) == FUNCTION_DECL
@@ -7483,6 +7483,7 @@ cp_maybe_mangle_decomp (tree decl, tree
for (unsigned int i = 0; i < count; i++, d = DECL_CHAIN (d))
v[count - i - 1] = d;
SET_DECL_ASSEMBLER_NAME (decl, mangle_decomp (decl, v));
+ maybe_apply_pragma_weak (decl);
}
}
--- gcc/testsuite/g++.dg/cpp1z/decomp42.C.jj 2018-04-05 13:45:39.521220008
+0200
+++ gcc/testsuite/g++.dg/cpp1z/decomp42.C 2018-04-05 13:45:22.507220268
+0200
@@ -0,0 +1,9 @@
+// PR c++/85208
+// { dg-do compile { target c++11 } }
+// { dg-require-weak "" }
+// { dg-options "" }
+
+#pragma weak _ZDC1d1e1fE
+struct A { int i, j, k; };
+auto [a, b, c] = A (); // { dg-warning "structured bindings only available
with" "" { target c++14_down } }
+auto [d, e, f] = A (); // { dg-warning "structured bindings only available
with" "" { target c++14_down } }
Jakub
