diff options
| -rw-r--r-- | clang/lib/AST/RecordLayoutBuilder.cpp | 9 | ||||
| -rw-r--r-- | clang/test/Layout/ms-x86-bitfields-vbases.cpp | 84 |
2 files changed, 93 insertions, 0 deletions
diff --git a/clang/lib/AST/RecordLayoutBuilder.cpp b/clang/lib/AST/RecordLayoutBuilder.cpp index 87d00bc9f5d..08c9da35873 100644 --- a/clang/lib/AST/RecordLayoutBuilder.cpp +++ b/clang/lib/AST/RecordLayoutBuilder.cpp @@ -2014,6 +2014,10 @@ static bool isMsLayout(const RecordDecl* D) { // one. // * The last zero size virtual base may be placed at the end of the struct. // and can potentially alias a zero sized type in the next struct. +// * If the last field is a non-zero length bitfield and we have any virtual +// bases then some extra padding is added before the virtual bases for no +// obvious reason. + namespace { struct MicrosoftRecordLayoutBuilder { @@ -2499,6 +2503,11 @@ void MicrosoftRecordLayoutBuilder::layoutVirtualBases(const CXXRecordDecl *RD) { llvm::SmallPtrSet<const CXXRecordDecl *, 2> HasVtordisp = computeVtorDispSet(RD); + // If the last field we laid out was a non-zero length bitfield then add some + // extra padding for no obvious reason. + if (LastFieldIsNonZeroWidthBitfield) + Size += CurrentBitfieldSize; + // Iterate through the virtual bases and lay them out. for (CXXRecordDecl::base_class_const_iterator i = RD->vbases_begin(), e = RD->vbases_end(); diff --git a/clang/test/Layout/ms-x86-bitfields-vbases.cpp b/clang/test/Layout/ms-x86-bitfields-vbases.cpp new file mode 100644 index 00000000000..e11ef67a634 --- /dev/null +++ b/clang/test/Layout/ms-x86-bitfields-vbases.cpp @@ -0,0 +1,84 @@ +// RUN: %clang_cc1 -fno-rtti -emit-llvm-only -triple i686-pc-win32 -fdump-record-layouts -fsyntax-only -cxx-abi microsoft %s 2>&1 \ +// RUN: | FileCheck %s +// RUN: %clang_cc1 -fno-rtti -emit-llvm-only -triple x86_64-pc-win32 -fdump-record-layouts -fsyntax-only -cxx-abi microsoft %s 2>/dev/null \ +// RUN: | FileCheck %s -check-prefix CHECK-X64 + +struct B0 { };
+
+struct A : virtual B0 { char a : 1; };
+ +// CHECK: *** Dumping AST Record Layout
+// CHECK: 0 | struct A
+// CHECK: 0 | (A vbtable pointer)
+// CHECK: 4 | char a
+// CHECK: 9 | struct B0 (virtual base) (empty)
+// CHECK: | [sizeof=9, align=4
+// CHECK: | nvsize=8, nvalign=4]
+// CHECK-X64: *** Dumping AST Record Layout +// CHECK-X64: 0 | struct A
+// CHECK-X64: 0 | (A vbtable pointer)
+// CHECK-X64: 8 | char a
+// CHECK-X64: 17 | struct B0 (virtual base) (empty)
+// CHECK-X64: | [sizeof=24, align=8
+// CHECK-X64: | nvsize=16, nvalign=8]
+ +struct B : virtual B0 { short a : 1; };
+ +// CHECK: *** Dumping AST Record Layout +// CHECK: 0 | struct B
+// CHECK: 0 | (B vbtable pointer)
+// CHECK: 4 | short a
+// CHECK: 10 | struct B0 (virtual base) (empty)
+// CHECK: | [sizeof=10, align=4
+// CHECK: | nvsize=8, nvalign=4]
+// CHECK-X64: *** Dumping AST Record Layout +// CHECK-X64: 0 | struct B
+// CHECK-X64: 0 | (B vbtable pointer)
+// CHECK-X64: 8 | short a
+// CHECK-X64: 18 | struct B0 (virtual base) (empty)
+// CHECK-X64: | [sizeof=24, align=8
+// CHECK-X64: | nvsize=16, nvalign=8]
+ +struct C : virtual B0 { char a : 1; char : 0; };
+ +// CHECK: *** Dumping AST Record Layout +// CHECK: 0 | struct C
+// CHECK: 0 | (C vbtable pointer)
+// CHECK: 4 | char a
+// CHECK: 5 | char
+// CHECK: 8 | struct B0 (virtual base) (empty)
+// CHECK: | [sizeof=8, align=4
+// CHECK: | nvsize=8, nvalign=4]
+// CHECK-X64: *** Dumping AST Record Layout +// CHECK-X64: 0 | struct C
+// CHECK-X64: 0 | (C vbtable pointer)
+// CHECK-X64: 8 | char a
+// CHECK-X64: 9 | char
+// CHECK-X64: 16 | struct B0 (virtual base) (empty)
+// CHECK-X64: | [sizeof=16, align=8
+// CHECK-X64: | nvsize=16, nvalign=8]
+ +struct D : virtual B0 { char a : 1; char b; };
+ +// CHECK: *** Dumping AST Record Layout +// CHECK: 0 | struct D
+// CHECK: 0 | (D vbtable pointer)
+// CHECK: 4 | char a
+// CHECK: 5 | char b
+// CHECK: 8 | struct B0 (virtual base) (empty)
+// CHECK: | [sizeof=8, align=4
+// CHECK: | nvsize=8, nvalign=4]
+// CHECK-X64: *** Dumping AST Record Layout +// CHECK-X64: 0 | struct D
+// CHECK-X64: 0 | (D vbtable pointer)
+// CHECK-X64: 8 | char a
+// CHECK-X64: 9 | char b
+// CHECK-X64: 16 | struct B0 (virtual base) (empty)
+// CHECK-X64: | [sizeof=16, align=8
+// CHECK-X64: | nvsize=16, nvalign=8]
+ +int a[ +sizeof(A)+ +sizeof(B)+ +sizeof(C)+ +sizeof(D)]; |
