Add partial support for using anonymous bitfields (e.g., int : 0) to enforce

alignment.  This fixes cases where the anonymous bitfield is followed by a 
non-bitfield member.  E.g.,

struct t4
{
  int foo : 1;
  long : 0;
  char bar;
};

Part of rdar://9859156

llvm-svn: 136858

1 files changed, 25 insertions, 10 deletions

diff --git a/clang/test/CodeGen/arm-apcs-zerolength-bitfield.c b/clang/test/CodeGen/arm-apcs-zerolength-bitfield.c
index 0b26d382e22..4b16e0c832b 100644
--- a/clang/test/CodeGen/arm-apcs-zerolength-bitfield.c
+++ b/clang/test/CodeGen/arm-apcs-zerolength-bitfield.c
@@ -1,4 +1,8 @@
 // RUN: %clang_cc1 -target-abi apcs-gnu -triple armv7-apple-darwin10 %s -verify
+//
+// Note: gcc forces the alignment to 4 bytes, regardless of the type of the
+// zero length bitfield.
+// rdar://9859156
 
 #include <stddef.h>
 
@@ -8,8 +12,8 @@ struct t1
   char : 0;
   char bar;
 };
-static int arr1_offset[(offsetof(struct t1, bar) == 1) ? 0 : -1];
-static int arr1_sizeof[(sizeof(struct t1) == 2) ? 0 : -1];
+static int arr1_offset[(offsetof(struct t1, bar) == 4) ? 0 : -1];
+static int arr1_sizeof[(sizeof(struct t1) == 8) ? 0 : -1];
 
 struct t2
 {
@@ -17,8 +21,8 @@ struct t2
   short : 0;
   char bar;
 };
-static int arr2_offset[(offsetof(struct t2, bar) == 1) ? 0 : -1];
-static int arr2_sizeof[(sizeof(struct t2) == 2) ? 0 : -1];
+static int arr2_offset[(offsetof(struct t2, bar) == 4) ? 0 : -1];
+static int arr2_sizeof[(sizeof(struct t2) == 8) ? 0 : -1];
 
 struct t3
 {
@@ -26,8 +30,8 @@ struct t3
   int : 0;
   char bar;
 };
-static int arr3_offset[(offsetof(struct t3, bar) == 1) ? 0 : -1];
-static int arr3_sizeof[(sizeof(struct t3) == 2) ? 0 : -1];
+static int arr3_offset[(offsetof(struct t3, bar) == 4) ? 0 : -1];
+static int arr3_sizeof[(sizeof(struct t3) == 8) ? 0 : -1];
 
 struct t4
 {
@@ -35,8 +39,8 @@ struct t4
   long : 0;
   char bar;
 };
-static int arr4_offset[(offsetof(struct t4, bar) == 1) ? 0 : -1];
-static int arr4_sizeof[(sizeof(struct t4) == 2) ? 0 : -1];
+static int arr4_offset[(offsetof(struct t4, bar) == 4) ? 0 : -1];
+static int arr4_sizeof[(sizeof(struct t4) == 8) ? 0 : -1];
 
 struct t5
 {
@@ -44,8 +48,8 @@ struct t5
   long long : 0;
   char bar;
 };
-static int arr5_offset[(offsetof(struct t5, bar) == 1) ? 0 : -1];
-static int arr5_sizeof[(sizeof(struct t5) == 2) ? 0 : -1];
+static int arr5_offset[(offsetof(struct t5, bar) == 4) ? 0 : -1];
+static int arr5_sizeof[(sizeof(struct t5) == 8) ? 0 : -1];
 
 struct t6
 {
@@ -109,6 +113,17 @@ struct t11
 static int arr11_offset[(offsetof(struct t11, bar2) == 1) ? 0 : -1];
 static int arr11_sizeof[(sizeof(struct t11) == 2) ? 0 : -1];
 
+struct t12
+{
+  int foo : 1;
+  char : 0;
+  long long : 0;
+  char : 0;
+  char bar;
+};
+static int arr12_offset[(offsetof(struct t12, bar) == 4) ? 0 : -1];
+static int arr12_sizeof[(sizeof(struct t12) == 8) ? 0 : -1];
+
 int main() {
   return 0;
 }