From c3a34659036b55fa36a5355fdd67133f427eeb2d Mon Sep 17 00:00:00 2001 From: Jakub Jelinek Date: Wed, 22 Apr 2020 16:44:42 +0200 Subject: [PATCH] calls: Introduce cxx17_empty_base_field_p [PR94383] As multiple targets are affected apparently, I believe at least aarch64, arm, powerpc64le, s390{,x} and ia64, I think we should have a middle-end predicate for this, so that if we need to tweak it, we can do it in one spot. 2020-04-22 Jakub Jelinek PR target/94383 * calls.h (cxx17_empty_base_field_p): Declare. * calls.c (cxx17_empty_base_field_p): Define. --- gcc/ChangeLog | 6 ++++++ gcc/calls.c | 18 ++++++++++++++++++ gcc/calls.h | 1 + 3 files changed, 25 insertions(+) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 961048adb2a..043ee407e8c 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2020-04-22 Jakub Jelinek + + PR target/94383 + * calls.h (cxx17_empty_base_field_p): Declare. + * calls.c (cxx17_empty_base_field_p): Define. + 2020-04-22 Christophe Lyon * doc/sourcebuild.texi (arm_softfp_ok, arm_hard_ok): Document. diff --git a/gcc/calls.c b/gcc/calls.c index 5bd922779af..9ac7f949737 100644 --- a/gcc/calls.c +++ b/gcc/calls.c @@ -6261,5 +6261,23 @@ must_pass_va_arg_in_stack (tree type) return targetm.calls.must_pass_in_stack (arg); } +/* Return true if FIELD is the C++17 empty base field that should + be ignored for ABI calling convention decisions in order to + maintain ABI compatibility between C++14 and earlier, which doesn't + add this FIELD to classes with empty bases, and C++17 and later + which does. */ + +bool +cxx17_empty_base_field_p (const_tree field) +{ + return (TREE_CODE (field) == FIELD_DECL + && DECL_ARTIFICIAL (field) + && RECORD_OR_UNION_TYPE_P (TREE_TYPE (field)) + && DECL_SIZE (field) + && integer_zerop (DECL_SIZE (field)) + && TYPE_SIZE (TREE_TYPE (field)) + && !integer_zerop (TYPE_SIZE (TREE_TYPE (field)))); +} + /* Tell the garbage collector about GTY markers in this source file. */ #include "gt-calls.h" diff --git a/gcc/calls.h b/gcc/calls.h index 9c9dd963fe2..4ee49360777 100644 --- a/gcc/calls.h +++ b/gcc/calls.h @@ -135,5 +135,6 @@ extern tree get_attr_nonstring_decl (tree, tree * = NULL); extern void maybe_warn_nonstring_arg (tree, tree); extern bool get_size_range (tree, tree[2], bool = false); extern rtx rtx_for_static_chain (const_tree, bool); +extern bool cxx17_empty_base_field_p (const_tree); #endif // GCC_CALLS_H -- 2.30.2