[PATCH 2/2] target/arm: Add compile time asserts to load/store_cpu_field macros

[Peter Maydell <peter.maydell@linaro.org>]

Add some compile-time asserts to the load_cpu_field() and store_cpu_field()
macros that the struct field being accessed is the expected size. This
lets us catch cases where we incorrectly tried to do a 32-bit load
from a 64-bit struct field.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 target/arm/translate-a32.h | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/target/arm/translate-a32.h b/target/arm/translate-a32.h
index 067044292a4..c2bc3ab8567 100644
--- a/target/arm/translate-a32.h
+++ b/target/arm/translate-a32.h
@@ -59,7 +59,12 @@ static inline TCGv_i32 load_cpu_offset(int offset)
     return tmp;
 }
 
-#define load_cpu_field(name) load_cpu_offset(offsetof(CPUARMState, name))
+/* Load from a 32-bit field to a TCGv_i32 */
+#define load_cpu_field(name)                                             \
+    ({                                                                   \
+        QEMU_BUILD_BUG_ON(sizeof(typeof_field(CPUARMState, name)) != 4); \
+        load_cpu_offset(offsetof(CPUARMState, name));                    \
+    })
 
 /* Load from the low half of a 64-bit field to a TCGv_i32 */
 #define load_cpu_field_low32(name)                                       \
@@ -70,9 +75,13 @@ static inline TCGv_i32 load_cpu_offset(int offset)
 
 void store_cpu_offset(TCGv_i32 var, int offset, int size);
 
-#define store_cpu_field(var, name)                              \
-    store_cpu_offset(var, offsetof(CPUARMState, name),          \
-                     sizeof_field(CPUARMState, name))
+#define store_cpu_field(val, name)                                      \
+    ({                                                                  \
+        QEMU_BUILD_BUG_ON(sizeof(typeof_field(CPUARMState, name)) != 4  \
+                          && sizeof(typeof_field(CPUARMState, name)) != 1); \
+        store_cpu_offset(val, offsetof(CPUARMState, name),              \
+                         sizeof_field(CPUARMState, name));              \
+    })
 
 #define store_cpu_field_constant(val, name) \
     store_cpu_field(tcg_constant_i32(val), name)
-- 
2.34.1