tree.h (DECL_OFFSET_ALIGN): Make the off_align field of the tree structure an exponent rather than an...

* tree.h (DECL_OFFSET_ALIGN): Make the off_align field of
the tree structure an exponent rather than an explicit alignment
so it doesn't overflow.
(SET_DECL_OFFSET_ALIGN): New macro.
* stor-layout.c (place_union_field): Use SET_DECL_OFFSET_ALIGN
rather than DECL_OFFSET_ALIGN.
(place_field): Likewise.
* expmed.c (store_bit_field): Abort on align==0 to avoid
antisocial machine behaviour.

From-SVN: r35659

1 files changed, 9 insertions, 2 deletions

diff --git a/gcc/tree.h b/gcc/tree.h
index 781ef43..e428a8a 100644
--- a/gcc/tree.h
+++ b/gcc/tree.h
@@ -1308,8 +1308,15 @@ struct tree_type
 #define DECL_SIZE_UNIT(NODE) (DECL_CHECK (NODE)->decl.size_unit)
 /* Holds the alignment required for the datum.  */
 #define DECL_ALIGN(NODE) (DECL_CHECK (NODE)->decl.u1.a.align)
-/* For FIELD_DECLs, holds the alignment that DECL_FIELD_OFFSET has.  */
-#define DECL_OFFSET_ALIGN(NODE) (FIELD_DECL_CHECK (NODE)->decl.u1.a.off_align)
+/* For FIELD_DECLs, off_align holds the number of low-order bits of
+   DECL_FIELD_OFFSET which are known to be always zero.
+   DECL_OFFSET_ALIGN thus returns the alignment that DECL_FIELD_OFFSET
+   has.  */
+#define DECL_OFFSET_ALIGN(NODE) \
+  (((unsigned HOST_WIDE_INT)1) << FIELD_DECL_CHECK (NODE)->decl.u1.a.off_align)
+/* Specify that DECL_ALIGN(NODE) is a multiple of X.  */
+#define SET_DECL_OFFSET_ALIGN(NODE, X) \
+  (FIELD_DECL_CHECK (NODE)->decl.u1.a.off_align	= exact_log2 ((X) & -(X)))
 /* 1 if the alignment for this type was requested by "aligned" attribute,
    0 if it is the default for this type.  */
 #define DECL_USER_ALIGN(NODE) (DECL_CHECK (NODE)->decl.user_align)