compiler, libgo: don't pad sparc64-linux epollevent
Change the compiler to not add zero padding because of zero-sized
fields named "_", since those can't be referenced anyhow.
Change the sparc-linux64 epollevent struct to name the alignment
field "_", to avoid zero padding.
Fixes https://gcc.gnu.org/PR103847
Change-Id: I591b3b798a24141e3d0e1ccf6ff0f7f0570af9d4
Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/374914
Trust: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>
diff --git a/go/types.cc b/go/types.cc
index 0f66661..57c02a9 100644
--- a/go/types.cc
+++ b/go/types.cc
@@ -6454,9 +6454,18 @@
? p->type()->get_backend_placeholder(gogo)
: p->type()->get_backend(gogo));
(*bfields)[i].location = p->location();
- lastsize = gogo->backend()->type_size((*bfields)[i].btype);
- if (lastsize != 0)
- saw_nonzero = true;
+ int64_t size = gogo->backend()->type_size((*bfields)[i].btype);
+ if (size != 0)
+ saw_nonzero = true;
+
+ if (size > 0 || !Gogo::is_sink_name(p->field_name()))
+ lastsize = size;
+ else
+ {
+ // There is an unreferenceable field of zero size. This
+ // doesn't affect whether we may need zero padding, so leave
+ // lastsize unchanged.
+ }
}
go_assert(i == fields->size());
if (saw_nonzero && lastsize == 0 && !type->is_results_struct())
diff --git a/libgo/mkrsysinfo.sh b/libgo/mkrsysinfo.sh
index 1864337..be15090 100755
--- a/libgo/mkrsysinfo.sh
+++ b/libgo/mkrsysinfo.sh
@@ -98,7 +98,7 @@
echo 'type epollevent struct { events uint32; data [8]byte }' >> ${OUT}
elif test "$val" = "8"; then
if test "$GOARCH" = "sparc64" -a "$GOOS" = "linux"; then
- echo 'type epollevent struct { events uint32; pad [4]byte; data [8]byte; _align [0]int64 }' >> ${OUT}
+ echo 'type epollevent struct { events uint32; pad [4]byte; data [8]byte; _ [0]int64 }' >> ${OUT}
else
echo 'type epollevent struct { events uint32; pad [4]byte; data [8]byte }' >> ${OUT}
fi
