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Implenment #pack pragma and ms_struct attribute layout. 

Concludes // radar://8823265.

llvm-svn: 131188
This commit is contained in:
Fariborz Jahanian 2011-05-11 16:58:31 +00:00
parent 69005e5953
commit 783243b3ca
2 changed files with 158 additions and 21 deletions
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48
clang/lib/AST/RecordLayoutBuilder.cpp
View File

@ -1259,6 +1259,7 @@ void RecordLayoutBuilder::LayoutFields(const RecordDecl *D) {
// the future, this will need to be tweakable by targets.
const FieldDecl *LastFD = 0;
ZeroLengthBitfield = 0;
unsigned RemainingInAlignment = 0;
for (RecordDecl::field_iterator Field = D->field_begin(),
FieldEnd = D->field_end(); Field != FieldEnd; ++Field) {
if (IsMsStruct) {
@ -1295,17 +1296,33 @@ void RecordLayoutBuilder::LayoutFields(const RecordDecl *D) {
// This check is needed for 'long long' in -m32 mode.
if (TypeSizeLastFD > FieldAlignLastFD)
FieldAlignLastFD = TypeSizeLastFD;
if (TypeSizeLastFD != TypeSize) {
if (RemainingInAlignment &&
LastFD && LastFD->isBitField() &&
LastFD->getBitWidth()->EvaluateAsInt(Context).getZExtValue()) {
// If previous field was a bitfield with some remaining unfilled
// bits, pad the field so current field starts on its type boundary.
uint64_t FieldOffset =
getDataSizeInBits() - UnfilledBitsInLastByte;
uint64_t NewSizeInBits = RemainingInAlignment + FieldOffset;
setDataSize(llvm::RoundUpToAlignment(NewSizeInBits,
Context.Target.getCharAlign()));
setSize(std::max(getSizeInBits(), getDataSizeInBits()));
RemainingInAlignment = 0;
}
uint64_t UnpaddedFieldOffset =
getDataSizeInBits() - UnfilledBitsInLastByte;
FieldAlign = std::max(FieldAlign, FieldAlignLastFD);
// The maximum field alignment overrides the aligned attribute.
if (!MaxFieldAlignment.isZero()) {
unsigned MaxFieldAlignmentInBits =
Context.toBits(MaxFieldAlignment);
FieldAlign = std::min(FieldAlign, MaxFieldAlignmentInBits);
}
uint64_t NewSizeInBits =
llvm::RoundUpToAlignment(UnpaddedFieldOffset, FieldAlign);
setDataSize(llvm::RoundUpToAlignment(NewSizeInBits,
@ -1313,11 +1330,40 @@ void RecordLayoutBuilder::LayoutFields(const RecordDecl *D) {
UnfilledBitsInLastByte = getDataSizeInBits() - NewSizeInBits;
setSize(std::max(getSizeInBits(), getDataSizeInBits()));
}
if (FD->isBitField()) {
uint64_t FieldSize =
FD->getBitWidth()->EvaluateAsInt(Context).getZExtValue();
assert (FieldSize > 0 && "LayoutFields - ms_struct layout");
if (RemainingInAlignment < FieldSize)
RemainingInAlignment = TypeSize - FieldSize;
else
RemainingInAlignment -= FieldSize;
}
}
else if (FD->isBitField()) {
uint64_t FieldSize =
FD->getBitWidth()->EvaluateAsInt(Context).getZExtValue();
std::pair<uint64_t, unsigned> FieldInfo =
Context.getTypeInfo(FD->getType());
uint64_t TypeSize = FieldInfo.first;
RemainingInAlignment = TypeSize - FieldSize;
}
LastFD = FD;
}
LayoutField(*Field);
}
if (IsMsStruct && RemainingInAlignment &&
LastFD && LastFD->isBitField() &&
LastFD->getBitWidth()->EvaluateAsInt(Context).getZExtValue()) {
// If we ended a bitfield before the full length of the type then
// pad the struct out to the full length of the last type.
uint64_t FieldOffset =
getDataSizeInBits() - UnfilledBitsInLastByte;
uint64_t NewSizeInBits = RemainingInAlignment + FieldOffset;
setDataSize(llvm::RoundUpToAlignment(NewSizeInBits,
Context.Target.getCharAlign()));
setSize(std::max(getSizeInBits(), getDataSizeInBits()));
}
}
void RecordLayoutBuilder::LayoutWideBitField(uint64_t FieldSize,

131
clang/test/CodeGen/ms_struct-pack.c
View File

@ -2,6 +2,36 @@
// rdar://8823265
#pragma pack(1)
struct _one_ms {
short m:9; // size is 2
int q:27; // size is 6
short w:13; // size is 8
short e:3; // size is 8
char r:4; // size is 9
char t:7; // size is 10
short y:16; // size is 12
short u:1; // size is 14
char i:2; // size is 15
int a; // size is 19
char o:6; // size is 20
char s:2; // size is 20
short d:10; // size is 22
short f:4; // size is 22
char b; // size is 23
char g:1; // size is 24
short h:13; // size is 26
char j:8; // size is 27
char k:5; // size is 28
char c; // size is 29
int l:28; // size is 33
char z:7; // size is 34
int x:20; // size is 38
} __attribute__((__ms_struct__));
typedef struct _one_ms one_ms;
static int a1[(sizeof(one_ms) == 38) - 1];
#pragma pack(2)
struct _two_ms {
short m:9; // size is 2
int q:27; // size is 6
@ -10,25 +40,86 @@ struct _two_ms {
char r:4; // size is 9
char t:7; // size is 10
short y:16; // size is 12
// clang and gcc start differing here. clang seems to follow the rules.
short u:1; // size is clang: 13 gcc:14
char i:2; // size is 14
int a; // size is 18
char o:6; // size is 19
char s:2; // size is 19
short d:10; // size is 21
short f:4; // size is 21
char b; // size is 22
char g:1; // size is 23
short h:13; // size is 25
char j:8; // size is 26
char k:5; // size is 27
char c; // size is 28
int l:28; // size is 32
char z:7; // size is 33
int x:20; // size is clang: 36 gcc:38
} __attribute__((__ms_struct__));
short u:1; // size is 14
char i:2; // size is 15
int a; // size is 19
char o:6; // size is 20
char s:2; // size is 20
short d:10; // size is 22
short f:4; // size is 22
char b; // size is 23
char g:1; // size is 24
short h:13; // size is 26
char j:8; // size is 27
char k:5; // size is 28
char c; // size is 29
int l:28; // size is 33
char z:7; // size is 34
int x:20; // size is 38
} __attribute__((__ms_struct__));
typedef struct _two_ms two_ms;
// gcc says size is 38, but its does not seem right!
static int a1[(sizeof(two_ms) == 36) - 1];
static int a2[(sizeof(two_ms) == 42) - 1];
#pragma pack(4)
struct _four_ms {
short m:9; // size is 2
int q:27; // size is 6
short w:13; // size is 8
short e:3; // size is 8
char r:4; // size is 9
char t:7; // size is 10
short y:16; // size is 12
short u:1; // size is 14
char i:2; // size is 15
int a; // size is 19
char o:6; // size is 20
char s:2; // size is 20
short d:10; // size is 22
short f:4; // size is 22
char b; // size is 23
char g:1; // size is 24
short h:13; // size is 26
char j:8; // size is 27
char k:5; // size is 28
char c; // size is 29
int l:28; // size is 33
char z:7; // size is 34
int x:20; // size is 38
} __attribute__((__ms_struct__));
typedef struct _four_ms four_ms;
static int a4[(sizeof(four_ms) == 48) - 1];
#pragma pack(8)
struct _eight_ms {
short m:9; // size is 2
int q:27; // size is 6
short w:13; // size is 8
short e:3; // size is 8
char r:4; // size is 9
char t:7; // size is 10
short y:16; // size is 12
short u:1; // size is 14
char i:2; // size is 15
int a; // size is 19
char o:6; // size is 20
char s:2; // size is 20
short d:10; // size is 22
short f:4; // size is 22
char b; // size is 23
char g:1; // size is 24
short h:13; // size is 26
char j:8; // size is 27
char k:5; // size is 28
char c; // size is 29
int l:28; // size is 33
char z:7; // size is 34
int x:20; // size is 38
} __attribute__((__ms_struct__));
typedef struct _eight_ms eight_ms;
static int a8[(sizeof(eight_ms) == 48) - 1];