r186536 - MS wide bitfield error check in Sema

[Reid Kleckner]

Author: rnk
Date: Wed Jul 17 15:46:03 2013
New Revision: 186536

URL: http://llvm.org/viewvc/llvm-project?rev=186536&view=rev
Log:
MS wide bitfield error check in Sema

cl.exe treats wide bitfields as an error. This patch causes them to be
an error if IsMsStruct is true, as it is in straight C.

Patch by Warren Hunt!

Reviewers: eli.friedman

Differential Revision: http://llvm-reviews.chandlerc.com/D1125

Added:
    cfe/trunk/test/SemaCXX/ms_wide_bitfield.cpp
Modified:
    cfe/trunk/include/clang/Sema/Sema.h
    cfe/trunk/lib/Sema/SemaDecl.cpp

Modified: cfe/trunk/include/clang/Sema/Sema.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Sema/Sema.h?rev=186536&r1=186535&r2=186536&view=diff
==============================================================================
--- cfe/trunk/include/clang/Sema/Sema.h (original)
+++ cfe/trunk/include/clang/Sema/Sema.h Wed Jul 17 15:46:03 2013
@@ -7286,8 +7286,8 @@ public:
   /// Returns false on success.
   /// Can optionally return whether the bit-field is of width 0
   ExprResult VerifyBitField(SourceLocation FieldLoc, IdentifierInfo *FieldName,
-                            QualType FieldTy, Expr *BitWidth,
-                            bool *ZeroWidth = 0);
+                            QualType FieldTy, bool IsMsStruct,
+                            Expr *BitWidth, bool *ZeroWidth = 0);
 
   enum CUDAFunctionTarget {
     CFT_Device,

Modified: cfe/trunk/lib/Sema/SemaDecl.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDecl.cpp?rev=186536&r1=186535&r2=186536&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaDecl.cpp (original)
+++ cfe/trunk/lib/Sema/SemaDecl.cpp Wed Jul 17 15:46:03 2013
@@ -10575,8 +10575,8 @@ void Sema::ActOnTagDefinitionError(Scope
 // Note that FieldName may be null for anonymous bitfields.
 ExprResult Sema::VerifyBitField(SourceLocation FieldLoc,
                                 IdentifierInfo *FieldName,
-                                QualType FieldTy, Expr *BitWidth,
-                                bool *ZeroWidth) {
+                                QualType FieldTy, bool IsMsStruct,
+                                Expr *BitWidth, bool *ZeroWidth) {
   // Default to true; that shouldn't confuse checks for emptiness
   if (ZeroWidth)
     *ZeroWidth = true;
@@ -10625,7 +10625,7 @@ ExprResult Sema::VerifyBitField(SourceLo
   if (!FieldTy->isDependentType()) {
     uint64_t TypeSize = Context.getTypeSize(FieldTy);
     if (Value.getZExtValue() > TypeSize) {
-      if (!getLangOpts().CPlusPlus) {
+      if (!getLangOpts().CPlusPlus || IsMsStruct) {
         if (FieldName) 
           return Diag(FieldLoc, diag::err_bitfield_width_exceeds_type_size)
             << FieldName << (unsigned)Value.getZExtValue() 
@@ -10843,7 +10843,8 @@ FieldDecl *Sema::CheckFieldDecl(Declarat
   bool ZeroWidth = false;
   // If this is declared as a bit-field, check the bit-field.
   if (!InvalidDecl && BitWidth) {
-    BitWidth = VerifyBitField(Loc, II, T, BitWidth, &ZeroWidth).take();
+    BitWidth = VerifyBitField(Loc, II, T, Record->isMsStruct(Context), BitWidth,
+                              &ZeroWidth).take();
     if (!BitWidth) {
       InvalidDecl = true;
       BitWidth = 0;
@@ -11024,7 +11025,8 @@ Decl *Sema::ActOnIvar(Scope *S,
 
   if (BitWidth) {
     // 6.7.2.1p3, 6.7.2.1p4
-    BitWidth = VerifyBitField(Loc, II, T, BitWidth).take();
+    BitWidth =
+        VerifyBitField(Loc, II, T, /*IsMsStruct=*/false, BitWidth).take();
     if (!BitWidth)
       D.setInvalidType();
   } else {

Added: cfe/trunk/test/SemaCXX/ms_wide_bitfield.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/ms_wide_bitfield.cpp?rev=186536&view=auto
==============================================================================
--- cfe/trunk/test/SemaCXX/ms_wide_bitfield.cpp (added)
+++ cfe/trunk/test/SemaCXX/ms_wide_bitfield.cpp Wed Jul 17 15:46:03 2013
@@ -0,0 +1,9 @@
+// RUN: %clang_cc1 -fno-rtti -emit-llvm-only -triple i686-pc-win32 -fdump-record-layouts -fsyntax-only -mms-bitfields -verify %s 2>&1
+
+struct A {
+  char a : 9; // expected-error{{size of bit-field 'a' (9 bits) exceeds size of its type (8 bits)}}
+  int b : 33; // expected-error{{size of bit-field 'b' (33 bits) exceeds size of its type (32 bits)}}
+  bool c : 9; // expected-error{{size of bit-field 'c' (9 bits) exceeds size of its type (8 bits)}}
+};
+
+int a[sizeof(A) == 1 ? 1 : -1];