OpenE2K/gcc
2
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

c++: Fix up value initialization of structs with zero width bitfields [PR102019]

Browse Source 
The removal of remove_zero_width_bit_fields, in addition to triggering
some ABI issues that need solving anyway (ABI incompatibility between
C and C++) also resulted in UB inside of gcc, we now call build_zero_init
which calls build_int_cst on an integral type with TYPE_PRECISION of 0.

Fixed by ignoring the zero width bitfields.  I understand
build_value_init_noctor wants to initialize to 0 even unnamed bitfields
(of non-zero width), at least until we have some CONSTRUCTOR flag that says
that even all the padding bits should be cleared.

2021-08-25  Jakub Jelinek  <jakub@redhat.com>

	PR c++/102019
	* init.c (build_value_init_noctor): Ignore unnamed zero-width
	bitfields.
This commit is contained in:
Jakub Jelinek 2021-08-25 22:35:21 +02:00
parent 5c85f29537
commit 1ab84eda55
1 changed files with 5 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
gcc/cp/init.c
View File

@ -427,6 +427,11 @@ build_value_init_noctor (tree type, tsubst_flags_t complain)
== NULL_TREE))
continue;
/* Ignore unnamed zero-width bitfields. */
if (DECL_UNNAMED_BIT_FIELD (field)
&& integer_zerop (DECL_SIZE (field)))
continue;
/* We could skip vfields and fields of types with
user-defined constructors, but I think that won't improve
performance at all; it should be simpler in general just