[PATCH] sim/d10v: Use offsetof in a static assertion about structure layout.

[John Baldwin <jhb@FreeBSD.org>]

clang 11 fails to compile the static assertion as it cannot compute
the pointer value at a compile time:

gdb/sim/d10v/interp.c:1149:37: error: static_assert expression is not an integral constant expression
  static_assert ((uintptr_t) &State == (uintptr_t) &State.regs,
                 ~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~
1 error generated.

Instead, assert that the offset of State.regs is 0.

sim/d10v/ChangeLog:

	* interp.c (sim_create_inferior): Use offsetof in static
	assertion.
---
 sim/d10v/ChangeLog | 5 +++++
 sim/d10v/interp.c  | 4 ++--
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/sim/d10v/ChangeLog b/sim/d10v/ChangeLog
index e45bd3833b0..d799d238db9 100644
--- a/sim/d10v/ChangeLog
+++ b/sim/d10v/ChangeLog
@@ -1,3 +1,8 @@
+2021-05-19  John Baldwin  <jhb@FreeBSD.org>
+
+	* interp.c (sim_create_inferior): Use offsetof in static
+	assertion.
+
 2021-05-17  Mike Frysinger  <vapier@gentoo.org>
 
 	* sim-main.h (SIM_HAVE_COMMON_SIM_STATE): Delete.
diff --git a/sim/d10v/interp.c b/sim/d10v/interp.c
index b56b204c72d..ee242f766f6 100644
--- a/sim/d10v/interp.c
+++ b/sim/d10v/interp.c
@@ -1146,8 +1146,8 @@ sim_create_inferior (SIM_DESC sd, struct bfd *abfd,
   bfd_vma start_address;
 
   /* Make sure we have the right structure for the following memset.  */
-  static_assert ((uintptr_t) &State == (uintptr_t) &State.regs,
-		 "&State != &State.regs");
+  static_assert (offsetof(typeof(State), regs) == 0,
+		 "State.regs is not at offset 0");
 
   /* Reset state from the regs field until the mem field.  */
   memset (&State, 0, (uintptr_t) &State.mem - (uintptr_t) &State.regs);
-- 
2.31.1