From: Fariborz Jahanian <fjahanian@apple.com>
Date: Fri, 6 May 2011 22:42:22 +0000 (+0000)
Subject: In ms_struct structs, Establish a new alignment for a
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=31e7f225fa3c603b84d66bc8ebdf7ed084e36e62;p=clang

In ms_struct structs, Establish a new alignment for a
non-bitfield following a bitfield if size of their types differ.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@131032 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/AST/RecordLayoutBuilder.cpp b/lib/AST/RecordLayoutBuilder.cpp
index 49c3b58510..4466be6ca2 100644
--- a/lib/AST/RecordLayoutBuilder.cpp
+++ b/lib/AST/RecordLayoutBuilder.cpp
@@ -1269,15 +1269,19 @@ void RecordLayoutBuilder::LayoutFields(const RecordDecl *D) {
       // ignored:
       else if (Context.ZeroBitfieldFollowsNonBitfield(FD, LastFD))
         continue;
+      // FIXME. streamline these conditions into a simple one.
       else if (Context.BitfieldFollowsBitfield(FD, LastFD) ||
-               Context.BitfieldFollowsNoneBitfield(FD, LastFD)) {
-        // Adjacent bit fields are packed into the same 1-, 2-, or
+               Context.BitfieldFollowsNoneBitfield(FD, LastFD) ||
+               Context.NoneBitfieldFollowsBitfield(FD, LastFD)) {
+        // 1) Adjacent bit fields are packed into the same 1-, 2-, or
         // 4-byte allocation unit if the integral types are the same
         // size and if the next bit field fits into the current
         // allocation unit without crossing the boundary imposed by the
         // common alignment requirements of the bit fields.
-        // Also, establish a new alignment for a bitfield following
+        // 2) Establish a new alignment for a bitfield following
         // a non-bitfield if size of their types differ.
+        // 3) Establish a new alignment for a non-bitfield following
+        // a bitfield if size of their types differ.
         std::pair<uint64_t, unsigned> FieldInfo = 
           Context.getTypeInfo(FD->getType());
         uint64_t TypeSize = FieldInfo.first;
diff --git a/test/CodeGen/ms_struct-bitfield-3.c b/test/CodeGen/ms_struct-bitfield-3.c
index 96782980dc..6798602f33 100644
--- a/test/CodeGen/ms_struct-bitfield-3.c
+++ b/test/CodeGen/ms_struct-bitfield-3.c
@@ -22,3 +22,18 @@ typedef struct _struct_0 struct_0;
 
 struct_0 test_struct_0 = { 18557917, 17, 3, 0, 80, 6487, 93 };
 static int a[(size_struct_0 == sizeof (struct_0)) -1];
+
+struct _struct_1 {
+  int d;
+  unsigned char a;
+  unsigned short b:7;
+  char c;
+} ATTR;
+
+typedef struct _struct_1 struct_1;
+
+#define size_struct_1 12
+
+struct_1 test_struct_1 = { 18557917, 'a', 3, 'b' };
+
+static int a1[(size_struct_1 == sizeof (struct_1)) -1];