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Fix bitfield handling for record layout with #pragma pack. <rdar://problem/10494810> and PR9560. 

llvm-svn: 145673
This commit is contained in:
Eli Friedman 2011-12-02 02:38:48 +00:00
parent a48d32bc9c
commit a91d38a435
2 changed files with 50 additions and 3 deletions
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8
clang/lib/AST/RecordLayoutBuilder.cpp
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@ -1690,18 +1690,20 @@ void RecordLayoutBuilder::LayoutBitField(const FieldDecl *D) {
UnpackedFieldAlign = std::max(UnpackedFieldAlign, D->getMaxAlignment());
// The maximum field alignment overrides the aligned attribute.
if (!MaxFieldAlignment.isZero()) {
if (!MaxFieldAlignment.isZero() && FieldSize != 0) {
unsigned MaxFieldAlignmentInBits = Context.toBits(MaxFieldAlignment);
FieldAlign = std::min(FieldAlign, MaxFieldAlignmentInBits);
UnpackedFieldAlign = std::min(UnpackedFieldAlign, MaxFieldAlignmentInBits);
}
// Check if we need to add padding to give the field the correct alignment.
if (FieldSize == 0 || (FieldOffset & (FieldAlign-1)) + FieldSize > TypeSize)
if (FieldSize == 0 || (MaxFieldAlignment.isZero() &&
(FieldOffset & (FieldAlign-1)) + FieldSize > TypeSize))
FieldOffset = llvm::RoundUpToAlignment(FieldOffset, FieldAlign);
if (FieldSize == 0 ||
(UnpackedFieldOffset & (UnpackedFieldAlign-1)) + FieldSize > TypeSize)
(MaxFieldAlignment.isZero() &&
(UnpackedFieldOffset & (UnpackedFieldAlign-1)) + FieldSize > TypeSize))
UnpackedFieldOffset = llvm::RoundUpToAlignment(UnpackedFieldOffset,
UnpackedFieldAlign);

45
clang/test/Sema/pragma-pack-5.c Normal file
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@ -0,0 +1,45 @@
// RUN: %clang_cc1 -triple x86_64-apple-darwin9 %s -fsyntax-only -verify -ffreestanding
// <rdar://problem/10494810> and PR9560
// Check #pragma pack handling with bitfields.
#include <stddef.h>
#pragma pack(2)
struct s0 {
char f1;
unsigned f2 : 32;
char f3;
};
extern int check[sizeof(struct s0) == 6 ? 1 : -1];
struct s1 {
char f1;
unsigned : 0;
char f3;
};
extern int check[sizeof(struct s1) == 5 ? 1 : -1];
struct s2 {
char f1;
unsigned : 0;
unsigned f3 : 8;
char f4;
};
extern int check[sizeof(struct s2) == 6 ? 1 : -1];
struct s3 {
char f1;
unsigned : 0;
unsigned f3 : 16;
char f4;
};
extern int check[sizeof(struct s3) == 8 ? 1 : -1];
extern int check[offsetof(struct s3, f4) == 6 ? 1 : -1];
struct s4 {
char f1;
unsigned f2 : 8;
char f3;
};
extern int check[sizeof(struct s4) == 4 ? 1 : -1];
extern int check[offsetof(struct s4, f3) == 2 ? 1 : -1];