From 366200045fc30290795e037ab2cb417ddd3c9933 Mon Sep 17 00:00:00 2001 From: Anders Carlsson Date: Thu, 3 Sep 2009 22:56:02 +0000 Subject: [PATCH] If the alignment of the chosen field in a union is greater than the alignment of the union, we need to use a packed LLVM struct. Fixes . git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@80964 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/CGRecordLayoutBuilder.cpp | 9 ++++++++- test/CodeGen/pragma-pack-3.c | 19 +++++++++++++++++++ 2 files changed, 27 insertions(+), 1 deletion(-) create mode 100644 test/CodeGen/pragma-pack-3.c diff --git a/lib/CodeGen/CGRecordLayoutBuilder.cpp b/lib/CodeGen/CGRecordLayoutBuilder.cpp index 74ef2eacc9..f2fd885ee4 100644 --- a/lib/CodeGen/CGRecordLayoutBuilder.cpp +++ b/lib/CodeGen/CGRecordLayoutBuilder.cpp @@ -199,8 +199,15 @@ void CGRecordLayoutBuilder::LayoutUnion(const RecordDecl *D) { } // Now add our field. - if (Ty) + if (Ty) { AppendField(0, Ty); + + if (getTypeAlignment(Ty) > Layout.getAlignment() / 8) { + // We need a packed struct. + Packed = true; + Align = 1; + } + } // Append tail padding. if (Layout.getSize() / 8 > Size) diff --git a/test/CodeGen/pragma-pack-3.c b/test/CodeGen/pragma-pack-3.c new file mode 100644 index 0000000000..b9166ae5d3 --- /dev/null +++ b/test/CodeGen/pragma-pack-3.c @@ -0,0 +1,19 @@ +// RUN: clang-cc -triple i386-apple-darwin9 %s -emit-llvm -o - | FileCheck -check-prefix X32 %s && +// CHECK-X32: %struct.menu = type <{ i8*, i8, i8 }> +// CHECK-X32: %union.command = type <{ i8*, [2 x i8] }> + +// RUN: clang-cc -triple x86_64-apple-darwin9 %s -emit-llvm -o - | FileCheck -check-prefix X64 %s +// CHECK-X64: %struct.menu = type <{ i8*, i8, i8 }> +// CHECK-X64: %union.command = type <{ i8*, [2 x i8] }> + +// +#pragma pack(push, 2) +typedef union command { + void *windowRef; + struct menu { + void *menuRef; + unsigned char menuItemIndex; + } menu; +} command; + +command c; -- 2.40.0