2006-01-28 Dale Johannesen <dalej@apple.com>apple/gcc-5316

        Radar 4420068
        * gcc.apple/bitreverse-17.c:  New.

2006-01-28  Dale Johannesen  <dalej@apple.com>

        Radar 4420068
        * stor-layout.c (place_field): don't adjust
        rli->bitpos and rli->offset after a non-bitfield
        whose type is zero-sized.



git-svn-id: https://gcc.gnu.org/svn/gcc/branches/apple-local-200502-branch@110328 138bc75d-0d04-0410-961f-82ee72b054a4

4 files changed, 95 insertions, 5 deletions

diff --git a/gcc/ChangeLog.apple-ppc b/gcc/ChangeLog.apple-ppc
index be55f043322..5a70f1af4de 100644
--- a/gcc/ChangeLog.apple-ppc
+++ b/gcc/ChangeLog.apple-ppc
@@ -1,3 +1,10 @@
+2006-01-28  Dale Johannesen  <dalej@apple.com>
+
+	Radar 4420068
+	* stor-layout.c (place_field): don't adjust
+	rli->bitpos and rli->offset after a non-bitfield
+	whose type is zero-sized.
+
 2006-01-27  Stuart Hastings  <stuart@apple.com>
 
 	Radar 4176531
diff --git a/gcc/stor-layout.c b/gcc/stor-layout.c
index 78c083e5b4d..4664171159e 100644
--- a/gcc/stor-layout.c
+++ b/gcc/stor-layout.c
@@ -918,7 +918,10 @@ place_field (record_layout_info rli, tree field)
 
       /* If the alignment is still within offset_align, just align
 	 the bit position.  */
-      if (desired_align < rli->offset_align)
+      /* APPLE LOCAL begin 4420068 */
+      if (desired_align < rli->offset_align
+	  && (!targetm.reverse_bitfields_p (rli->t) || rli->bitfield_seen))
+      /* APPLE LOCAL end 4420068 */
 	rli->bitpos = round_up (rli->bitpos, desired_align);
       else
 	{
@@ -1272,9 +1275,9 @@ place_field (record_layout_info rli, tree field)
     {
       rli->bitpos = size_binop (PLUS_EXPR, rli->bitpos, DECL_SIZE (field));
       normalize_rli (rli);
-      /* APPLE LOCAL begin 4401223 4401224 */
+      /* APPLE LOCAL begin 4401223 4401224 4420068 */
       if (targetm.reverse_bitfields_p (rli->t) && !DECL_BIT_FIELD_TYPE (field)
-	  && !rli->bitfield_seen)
+	  && !rli->bitfield_seen && !integer_zerop (TYPE_SIZE (TREE_TYPE (field))))
 	{
 	  tree tsize = TYPE_SIZE (TREE_TYPE (field));
 	  /* If we've gone into the next word, move "offset" forward and
@@ -1282,7 +1285,10 @@ place_field (record_layout_info rli, tree field)
 	     non-bitfields to get following bitfields laid out correctly.
 	     However, if we've already seen a bitfield earlier in the 
 	     struct, don't do this compensation.  This makes no sense
-	     and results in overlapping fields, but is what CW does.  */
+	     and results in overlapping fields, but is what CW does.
+	     (If this field has a 0-sized type, we have not advanced from the
+	     previous field, so there's no need to do anything.  Conveniently,
+	     this avoids an infinite loop here.) */
 	  while (! INT_CST_LT_UNSIGNED (rli->bitpos, tsize))
 	    {
 	      rli->offset = size_binop (PLUS_EXPR, rli->offset, 
@@ -1291,7 +1297,7 @@ place_field (record_layout_info rli, tree field)
 					tsize);
 	    }
 	}
-      /* APPLE LOCAL end 4401223 4401224 */
+      /* APPLE LOCAL end 4401223 4401224 4420068 */
     }
 }
 
diff --git a/gcc/testsuite/ChangeLog.apple-ppc b/gcc/testsuite/ChangeLog.apple-ppc
index 8d99ddbb85f..32667e45869 100644
--- a/gcc/testsuite/ChangeLog.apple-ppc
+++ b/gcc/testsuite/ChangeLog.apple-ppc
@@ -1,3 +1,8 @@
+2006-01-28  Dale Johannesen  <dalej@apple.com>
+
+	Radar 4420068
+	* gcc.apple/bitreverse-17.c:  New.
+
 2006-01-27  Stuart Hastings  <stuart@apple.com>
 
 	Radar 4176531
diff --git a/gcc/testsuite/gcc.apple/bitreverse-17.c b/gcc/testsuite/gcc.apple/bitreverse-17.c
new file mode 100644
index 00000000000..bfc0c0f5a34
--- /dev/null
+++ b/gcc/testsuite/gcc.apple/bitreverse-17.c
@@ -0,0 +1,72 @@
+/* APPLE LOCAL file 4420068 */
+/* Exercise zero-length fields. */
+
+/* { dg-do run { target powerpc*-*-darwin* } } */
+/* { dg-options "-std=gnu99" } */
+
+#pragma reverse_bitfields on
+struct empty {};
+
+struct uc0 { unsigned char content[0]; };
+
+struct nest_uc0 { struct uc0 foo; };
+
+struct uc0_uib2 { unsigned char foo[0]; unsigned int xx : 2; };
+
+struct nest_nest_uc0_uib3 { struct nest_uc0 xx; unsigned int yy : 3; };
+
+struct nest_empty_uib3 { struct empty e; unsigned int zz : 3; };
+
+union size0 { struct empty e; int i[0]; };
+
+union u0 { struct uc0 ss; unsigned int i; };
+
+union u1 { struct nest_uc0 ss; unsigned int i; };
+
+union u2 { struct uc0_uib2 ss; unsigned int i; };
+
+union u3 { struct nest_nest_uc0_uib3 ss; unsigned int i; };
+
+union u4 { struct nest_empty_uib3 ss; unsigned int i; };
+
+union u5 { union size0 ss; unsigned int i; };
+
+struct advance {
+  char c;
+  int spacer[0];
+  char d;
+};
+
+struct advance2 {
+  char c;
+  struct empty s;
+  char d;
+};
+
+struct advance3 {
+  char c;
+  union size0 u;
+  char d;
+};
+
+int main() {
+  
+  if (sizeof(struct empty) !=0 ||
+    sizeof(struct uc0) !=0 
+    || sizeof(struct uc0_uib2) != 4
+    || sizeof(struct nest_nest_uc0_uib3) != 4
+    || sizeof(struct nest_empty_uib3) != 4
+    || sizeof(union size0) != 0
+    || sizeof(union u0) != 4
+    || sizeof(union u1) != 4
+    || sizeof(union u2) != 4
+    || sizeof(union u3) != 4
+    || sizeof(union u4) != 4
+    || sizeof(union u5) != 4
+    || sizeof(struct advance) != 8
+    || sizeof(struct advance2) != 2
+    || sizeof(struct advance3) != 8)
+    return 42;
+  return 0;
+}
+ 
\ No newline at end of file