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Makefile: Extend noinline workarounds for LTO and -O2 to gcc 12

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Commit 1a563a0cbd ("passt: Address gcc 11 warnings") works around an
issue where the remote address passed to hash functions is seen as
uninitialised by gcc, with -flto and -O2.

It turns out we get the same exact behaviour on gcc 12.1 and 12.2, so
extend the applicability of the same workaround to gcc 12.

Don't go further than that, though: should the issue reported at:
  https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78993
happen to be fixed in a later version of gcc, we won't need the
noinline attributes anymore. Otherwise, we'll notice.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
This commit is contained in:
Stefano Brivio 2022-09-28 20:36:57 +02:00
parent 65b649017c
commit 505a33e9f9
1 changed files with 3 additions and 3 deletions
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6
Makefile
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@ -45,12 +45,12 @@ PASST_HEADERS = arch.h arp.h checksum.h conf.h dhcp.h dhcpv6.h icmp.h \
pcap.h port_fwd.h siphash.h tap.h tcp.h tcp_splice.h udp.h util.h
HEADERS = $(PASST_HEADERS) seccomp.h
# On gcc 11.2, with -O2 and -flto, tcp_hash() and siphash_20b(), if inlined,
# seem to be hitting something similar to:
# On gcc 11 and 12, with -O2 and -flto, tcp_hash() and siphash_20b(), if
# inlined, seem to be hitting something similar to:
# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78993
# from the pointer arithmetic used from the tcp_tap_handler() path to get the
# remote connection address.
ifeq ($(shell $(CC) -dumpversion),11)
ifeq (,$(filter-out 11 12, $(shell $(CC) -dumpversion)))
ifneq (,$(filter -flto%,$(FLAGS) $(CFLAGS)))
ifneq (,$(filter -O2,$(FLAGS) $(CFLAGS)))
FLAGS += -DTCP_HASH_NOINLINE