r323921 - [PR32482] Fix bitfield layout for -mms-bitfield and pragma pack
Alex Lorenz via cfe-commits
cfe-commits at lists.llvm.org
Wed Jan 31 13:59:02 PST 2018
Author: arphaman
Date: Wed Jan 31 13:59:02 2018
New Revision: 323921
URL: http://llvm.org/viewvc/llvm-project?rev=323921&view=rev
Log:
[PR32482] Fix bitfield layout for -mms-bitfield and pragma pack
The patch ensures that a new storage unit is created when the new bitfield's
size is wider than the available bits.
rdar://36343145
Differential Revision: https://reviews.llvm.org/D42660
Modified:
cfe/trunk/lib/AST/RecordLayoutBuilder.cpp
cfe/trunk/test/CodeGen/mms-bitfields.c
cfe/trunk/test/Sema/mms-bitfields.c
Modified: cfe/trunk/lib/AST/RecordLayoutBuilder.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/RecordLayoutBuilder.cpp?rev=323921&r1=323920&r2=323921&view=diff
==============================================================================
--- cfe/trunk/lib/AST/RecordLayoutBuilder.cpp (original)
+++ cfe/trunk/lib/AST/RecordLayoutBuilder.cpp Wed Jan 31 13:59:02 2018
@@ -1504,9 +1504,10 @@ void ItaniumRecordLayoutBuilder::LayoutB
FieldAlign = TypeSize;
// If the previous field was not a bitfield, or was a bitfield
- // with a different storage unit size, we're done with that
- // storage unit.
- if (LastBitfieldTypeSize != TypeSize) {
+ // with a different storage unit size, or if this field doesn't fit into
+ // the current storage unit, we're done with that storage unit.
+ if (LastBitfieldTypeSize != TypeSize ||
+ UnfilledBitsInLastUnit < FieldSize) {
// Also, ignore zero-length bitfields after non-bitfields.
if (!LastBitfieldTypeSize && !FieldSize)
FieldAlign = 1;
Modified: cfe/trunk/test/CodeGen/mms-bitfields.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/mms-bitfields.c?rev=323921&r1=323920&r2=323921&view=diff
==============================================================================
--- cfe/trunk/test/CodeGen/mms-bitfields.c (original)
+++ cfe/trunk/test/CodeGen/mms-bitfields.c Wed Jan 31 13:59:02 2018
@@ -20,3 +20,46 @@ struct s3 {
} s3;
// CHECK: %struct.s3 = type { i32, [4 x i8], %struct.s1 }
+
+// PR32482:
+
+#pragma pack (push,1)
+
+typedef unsigned int UINT32;
+
+struct Inner {
+ UINT32 A : 1;
+ UINT32 B : 1;
+ UINT32 C : 1;
+ UINT32 D : 30;
+} Inner;
+
+#pragma pack (pop)
+
+// CHECK: %struct.Inner = type { i32, i32 }
+
+// CHECK: %struct.A = type { i32, i32, i32 }
+
+#pragma pack(push, 1)
+
+union HEADER {
+ struct A {
+ int : 3; // Bits 2:0
+ int a : 9; // Bits 11:3
+ int : 12; // Bits 23:12
+ int b : 17; // Bits 40:24
+ int : 7; // Bits 47:41
+ int c : 4; // Bits 51:48
+ int : 4; // Bits 55:52
+ int d : 3; // Bits 58:56
+ int : 5; // Bits 63:59
+ } Bits;
+} HEADER;
+
+#pragma pack(pop)
+
+struct Inner variable = { 1,0,1, 21 };
+union HEADER hdr = {{1,2,3,4}};
+
+// CHECK: @variable = global { i8, [3 x i8], i8, i8, i8, i8 } { i8 5, [3 x i8] undef, i8 21, i8 0, i8 0, i8 0 }, align 1
+// CHECK: @hdr = global { { i8, i8, [2 x i8], i8, i8, i8, i8, i8, [3 x i8] } } { { i8, i8, [2 x i8], i8, i8, i8, i8, i8, [3 x i8] } { i8 8, i8 0, [2 x i8] undef, i8 2, i8 0, i8 0, i8 3, i8 4, [3 x i8] undef } }, align 1
Modified: cfe/trunk/test/Sema/mms-bitfields.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/mms-bitfields.c?rev=323921&r1=323920&r2=323921&view=diff
==============================================================================
--- cfe/trunk/test/Sema/mms-bitfields.c (original)
+++ cfe/trunk/test/Sema/mms-bitfields.c Wed Jan 31 13:59:02 2018
@@ -11,3 +11,18 @@ struct
// MS pads out bitfields between different types.
static int arr[(sizeof(t) == 8) ? 1 : -1];
+
+#pragma pack (push,1)
+
+typedef unsigned int UINT32;
+
+struct Inner {
+ UINT32 A : 1;
+ UINT32 B : 1;
+ UINT32 C : 1;
+ UINT32 D : 30;
+} Inner;
+
+#pragma pack (pop)
+
+static int arr2[(sizeof(Inner) == 8) ? 1 : -1];
More information about the cfe-commits
mailing list