[llvm-branch-commits] [cfe-branch] r102080 - in /cfe/branches/Apple/williamson: lib/CodeGen/CGRecordLayoutBuilder.cpp test/CodeGenCXX/bitfield-layout.cpp

[Daniel Dunbar]

Author: ddunbar
Date: Thu Apr 22 12:01:35 2010
New Revision: 102080

URL: http://llvm.org/viewvc/llvm-project?rev=102080&view=rev
Log:
Simplify wide bit-field layout in CGRecordLayoutBuilder, and also fix a bug where assigning to a bit-field member would overwrite other parts of the struct.

Modified:
    cfe/branches/Apple/williamson/lib/CodeGen/CGRecordLayoutBuilder.cpp
    cfe/branches/Apple/williamson/test/CodeGenCXX/bitfield-layout.cpp

Modified: cfe/branches/Apple/williamson/lib/CodeGen/CGRecordLayoutBuilder.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/branches/Apple/williamson/lib/CodeGen/CGRecordLayoutBuilder.cpp?rev=102080&r1=102079&r2=102080&view=diff
==============================================================================
--- cfe/branches/Apple/williamson/lib/CodeGen/CGRecordLayoutBuilder.cpp (original)
+++ cfe/branches/Apple/williamson/lib/CodeGen/CGRecordLayoutBuilder.cpp Thu Apr 22 12:01:35 2010
@@ -161,21 +161,16 @@
   bool IsSigned = FD->getType()->isSignedIntegerType();
 
   if (FieldSize > TypeSizeInBits) {
-    // We have a wide bit-field.
-    
-    CGBitFieldInfo::AccessInfo Component;
-
-    Component.FieldIndex = 0;
-    Component.FieldByteOffset =
-      TypeSizeInBytes * ((FieldOffset / 8) / TypeSizeInBytes);
-    Component.FieldBitStart = 0;
-    Component.AccessWidth = TypeSizeInBits;
-    // FIXME: This might be wrong!
-    Component.AccessAlignment = 0;
-    Component.TargetBitOffset = 0;
-    Component.TargetBitWidth = TypeSizeInBits;
-    
-    return CGBitFieldInfo(TypeSizeInBits, 1, &Component, IsSigned);
+    // We have a wide bit-field. The extra bits are only used for padding, so
+    // if we have a bitfield of type T, with size N:
+    //
+    // T t : N;
+    //
+    // We can just assume that it's:
+    //
+    // T t : sizeof(T);
+    //
+    FieldSize = TypeSizeInBits;
   }
 
   unsigned StartBit = FieldOffset % TypeSizeInBits;

Modified: cfe/branches/Apple/williamson/test/CodeGenCXX/bitfield-layout.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/branches/Apple/williamson/test/CodeGenCXX/bitfield-layout.cpp?rev=102080&r1=102079&r2=102080&view=diff
==============================================================================
--- cfe/branches/Apple/williamson/test/CodeGenCXX/bitfield-layout.cpp (original)
+++ cfe/branches/Apple/williamson/test/CodeGenCXX/bitfield-layout.cpp Thu Apr 22 12:01:35 2010
@@ -1,17 +1,43 @@
-// RUN: %clang_cc1 %s -triple=x86_64-apple-darwin10 -emit-llvm -o - | FileCheck %s
+// RUN: %clang_cc1 %s -triple=x86_64-apple-darwin10 -emit-llvm -o - -O3 | FileCheck -check-prefix LP64 %s
+// RUN: %clang_cc1 %s -triple=i386-apple-darwin10 -emit-llvm -o - -O3 | FileCheck -check-prefix LP32 %s
 
-// CHECK: %union.Test1 = type { i32, [4 x i8] }
+// CHECK-LP64: %union.Test1 = type { i32, [4 x i8] }
 union Test1 {
   int a;
   int b: 39;
 } t1;
 
-// CHECK: %union.Test2 = type { i8 }
+// CHECK-LP64: %union.Test2 = type { i8 }
 union Test2 {
   int : 6;
 } t2;
 
-// CHECK: %union.Test3 = type { [2 x i8] }
+// CHECK-LP64: %union.Test3 = type { [2 x i8] }
 union Test3 {
   int : 9;
 } t3;
+
+
+#define CHECK(x) if (!(x)) return __LINE__
+
+int f() {
+  struct {
+    int a;
+
+    unsigned long long b : 65;
+
+    int c;
+  } c;
+  
+  c.a = 0;
+  c.b = (unsigned long long)-1;
+  c.c = 0;
+
+  CHECK(c.a == 0);
+  CHECK(c.b == (unsigned long long)-1);
+  CHECK(c.c == 0);
+
+// CHECK-LP64: ret i32 0
+// CHECK-LP32: ret i32 0
+  return 0;
+}