Speculatively revert "IRgen: Move EmitStoreThroughBitfieldLValue to use new CGBitfieldInfo::AccessInfo decomposition, instead of computing the access policy itself.", I think it might be breaking bootstrap.

llvm-svn: 101235
This commit is contained in:
Daniel Dunbar 2010-04-14 05:48:35 +00:00
parent 80ee5e299c
commit 91ea6ac3e9
2 changed files with 79 additions and 249 deletions

View File

@ -600,6 +600,21 @@ RValue CodeGenFunction::EmitLoadOfLValue(LValue LV, QualType ExprType) {
return EmitLoadOfKVCRefLValue(LV, ExprType);
}
static llvm::Value *getBitFieldAddr(LValue LV, CGBuilderTy &Builder) {
const CGBitFieldInfo &Info = LV.getBitFieldInfo();
llvm::Value *BaseValue = LV.getBitFieldBaseAddr();
const llvm::PointerType *BaseTy =
cast<llvm::PointerType>(BaseValue->getType());
// Cast to the type of the access we will perform.
llvm::Value *V = Builder.CreateBitCast(
BaseValue, llvm::PointerType::get(Info.FieldTy, BaseTy->getAddressSpace()));
// Offset by the access index.
return Builder.CreateConstGEP1_32(V, Info.FieldNo);
}
RValue CodeGenFunction::EmitLoadOfBitfieldLValue(LValue LV,
QualType ExprType) {
const CGBitFieldInfo &Info = LV.getBitFieldInfo();
@ -641,7 +656,7 @@ RValue CodeGenFunction::EmitLoadOfBitfieldLValue(LValue LV,
// Shift out unused low bits and mask out unused high bits.
llvm::Value *Val = Load;
if (AI.FieldBitStart)
Val = Builder.CreateLShr(Load, AI.FieldBitStart);
Val = Builder.CreateAShr(Load, AI.FieldBitStart);
Val = Builder.CreateAnd(Val, llvm::APInt::getLowBitsSet(AI.AccessWidth,
AI.TargetBitWidth),
"bf.clear");
@ -663,7 +678,7 @@ RValue CodeGenFunction::EmitLoadOfBitfieldLValue(LValue LV,
// FIXME: This can easily be folded into the load of the high bits, which
// could also eliminate the mask of high bits in some situations.
if (Info.isSigned()) {
unsigned ExtraBits = ResSizeInBits - Info.getSize();
unsigned ExtraBits = ResSizeInBits - Info.Size;
if (ExtraBits)
Res = Builder.CreateAShr(Builder.CreateShl(Res, ExtraBits),
ExtraBits, "bf.val.sext");
@ -790,97 +805,88 @@ void CodeGenFunction::EmitStoreThroughBitfieldLValue(RValue Src, LValue Dst,
QualType Ty,
llvm::Value **Result) {
const CGBitFieldInfo &Info = Dst.getBitFieldInfo();
unsigned StartBit = Info.Start;
unsigned BitfieldSize = Info.Size;
llvm::Value *Ptr = getBitFieldAddr(Dst, Builder);
// Get the output type.
const llvm::Type *ResLTy = ConvertType(Ty);
unsigned ResSizeInBits = CGM.getTargetData().getTypeSizeInBits(ResLTy);
const llvm::Type *EltTy =
cast<llvm::PointerType>(Ptr->getType())->getElementType();
unsigned EltTySize = CGM.getTargetData().getTypeSizeInBits(EltTy);
// Get the source value, truncated to the width of the bit-field.
// Get the new value, cast to the appropriate type and masked to exactly the
// size of the bit-field.
llvm::Value *SrcVal = Src.getScalarVal();
SrcVal = Builder.CreateAnd(SrcVal, llvm::APInt::getLowBitsSet(ResSizeInBits,
Info.getSize()),
"bf.value");
llvm::Value *NewVal = Builder.CreateIntCast(SrcVal, EltTy, false, "tmp");
llvm::Constant *Mask = llvm::ConstantInt::get(VMContext,
llvm::APInt::getLowBitsSet(EltTySize, BitfieldSize));
NewVal = Builder.CreateAnd(NewVal, Mask, "bf.value");
// Return the new value of the bit-field, if requested.
if (Result) {
// Cast back to the proper type for result.
const llvm::Type *SrcTy = Src.getScalarVal()->getType();
llvm::Value *ReloadVal = Builder.CreateIntCast(SrcVal, SrcTy, false,
"bf.reload.val");
const llvm::Type *SrcTy = SrcVal->getType();
llvm::Value *SrcTrunc = Builder.CreateIntCast(NewVal, SrcTy, false,
"bf.reload.val");
// Sign extend if necessary.
if (Info.isSigned()) {
unsigned ExtraBits = ResSizeInBits - Info.getSize();
if (ExtraBits)
ReloadVal = Builder.CreateAShr(Builder.CreateShl(ReloadVal, ExtraBits),
ExtraBits, "bf.reload.sext");
if (Info.IsSigned) {
unsigned SrcTySize = CGM.getTargetData().getTypeSizeInBits(SrcTy);
llvm::Value *ExtraBits = llvm::ConstantInt::get(SrcTy,
SrcTySize - BitfieldSize);
SrcTrunc = Builder.CreateAShr(Builder.CreateShl(SrcTrunc, ExtraBits),
ExtraBits, "bf.reload.sext");
}
*Result = ReloadVal;
*Result = SrcTrunc;
}
// Iterate over the components, writing each piece to memory.
for (unsigned i = 0, e = Info.getNumComponents(); i != e; ++i) {
const CGBitFieldInfo::AccessInfo &AI = Info.getComponent(i);
// In some cases the bitfield may straddle two memory locations. Emit the low
// part first and check to see if the high needs to be done.
unsigned LowBits = std::min(BitfieldSize, EltTySize - StartBit);
llvm::Value *LowVal = Builder.CreateLoad(Ptr, Dst.isVolatileQualified(),
"bf.prev.low");
// Get the field pointer.
llvm::Value *Ptr = Dst.getBitFieldBaseAddr();
// Compute the mask for zero-ing the low part of this bitfield.
llvm::Constant *InvMask =
llvm::ConstantInt::get(VMContext,
~llvm::APInt::getBitsSet(EltTySize, StartBit, StartBit + LowBits));
// Only offset by the field index if used, so that incoming values are not
// required to be structures.
if (AI.FieldIndex)
Ptr = Builder.CreateStructGEP(Ptr, AI.FieldIndex, "bf.field");
// Compute the new low part as
// LowVal = (LowVal & InvMask) | (NewVal << StartBit),
// with the shift of NewVal implicitly stripping the high bits.
llvm::Value *NewLowVal =
Builder.CreateShl(NewVal, StartBit, "bf.value.lo");
LowVal = Builder.CreateAnd(LowVal, InvMask, "bf.prev.lo.cleared");
LowVal = Builder.CreateOr(LowVal, NewLowVal, "bf.new.lo");
// Offset by the byte offset, if used.
if (AI.FieldByteOffset) {
const llvm::Type *i8PTy = llvm::Type::getInt8PtrTy(VMContext);
Ptr = Builder.CreateBitCast(Ptr, i8PTy);
Ptr = Builder.CreateConstGEP1_32(Ptr, AI.FieldByteOffset,"bf.field.offs");
}
// Write back.
Builder.CreateStore(LowVal, Ptr, Dst.isVolatileQualified());
// Cast to the access type.
const llvm::Type *PTy = llvm::Type::getIntNPtrTy(VMContext, AI.AccessWidth,
Ty.getAddressSpace());
Ptr = Builder.CreateBitCast(Ptr, PTy);
// If the low part doesn't cover the bitfield emit a high part.
if (LowBits < BitfieldSize) {
unsigned HighBits = BitfieldSize - LowBits;
llvm::Value *HighPtr = Builder.CreateGEP(Ptr, llvm::ConstantInt::get(
llvm::Type::getInt32Ty(VMContext), 1), "bf.ptr.hi");
llvm::Value *HighVal = Builder.CreateLoad(HighPtr,
Dst.isVolatileQualified(),
"bf.prev.hi");
// Extract the piece of the bit-field value to write in this access, shifted
// and masked for placement into memory.
llvm::Value *Val = SrcVal;
if (AI.TargetBitOffset)
Val = Builder.CreateLShr(Val, AI.TargetBitOffset);
Val = Builder.CreateAnd(Val, llvm::APInt::getLowBitsSet(ResSizeInBits,
AI.TargetBitWidth));
if (AI.FieldBitStart)
Val = Builder.CreateShl(Val, AI.FieldBitStart);
// Compute the mask for zero-ing the high part of this bitfield.
llvm::Constant *InvMask =
llvm::ConstantInt::get(VMContext, ~llvm::APInt::getLowBitsSet(EltTySize,
HighBits));
// Extend or truncate to the access size.
const llvm::Type *AccessLTy =
llvm::Type::getIntNTy(VMContext, AI.AccessWidth);
if (ResSizeInBits < AI.AccessWidth)
Val = Builder.CreateZExt(Val, AccessLTy);
else if (ResSizeInBits > AI.AccessWidth)
Val = Builder.CreateTrunc(Val, AccessLTy);
// Compute the new high part as
// HighVal = (HighVal & InvMask) | (NewVal lshr LowBits),
// where the high bits of NewVal have already been cleared and the
// shift stripping the low bits.
llvm::Value *NewHighVal =
Builder.CreateLShr(NewVal, LowBits, "bf.value.high");
HighVal = Builder.CreateAnd(HighVal, InvMask, "bf.prev.hi.cleared");
HighVal = Builder.CreateOr(HighVal, NewHighVal, "bf.new.hi");
// If necessary, load and OR in bits that are outside of the bit-field.
if (AI.TargetBitWidth != AI.AccessWidth) {
llvm::LoadInst *Load = Builder.CreateLoad(Ptr, Dst.isVolatileQualified());
if (AI.AccessAlignment)
Load->setAlignment(AI.AccessAlignment);
// Compute the mask for zeroing the bits that are part of the bit-field.
llvm::APInt InvMask =
~llvm::APInt::getBitsSet(AI.AccessWidth, AI.FieldBitStart,
AI.FieldBitStart + AI.TargetBitWidth);
// Apply the mask and OR in to the value to write.
Val = Builder.CreateOr(Val, Builder.CreateAnd(Load, InvMask));
}
// Write the value.
llvm::StoreInst *Store = Builder.CreateStore(Val, Ptr,
Dst.isVolatileQualified());
if (AI.AccessAlignment)
Store->setAlignment(AI.AccessAlignment);
// Write back.
Builder.CreateStore(HighVal, HighPtr, Dst.isVolatileQualified());
}
}

View File

@ -1,176 +0,0 @@
// RUN: %clang_cc1 -emit-llvm -triple x86_64 -O3 -o - %s | \
// RUN: FileCheck -check-prefix=CHECK-OPT %s
/****/
// PR6176
struct __attribute((packed)) s0 {
int f0 : 24;
};
struct s0 g0 = { 0xdeadbeef };
int f0_load(struct s0 *a0) {
int size_check[sizeof(struct s0) == 3 ? 1 : -1];
return a0->f0;
}
int f0_store(struct s0 *a0) {
return (a0->f0 = 1);
}
int f0_reload(struct s0 *a0) {
return (a0->f0 += 1);
}
// CHECK-OPT: define i64 @test_0()
// CHECK-OPT: ret i64 1
// CHECK-OPT: }
unsigned long long test_0() {
struct s0 g0 = { 0xdeadbeef };
unsigned long long res = 0;
res ^= g0.f0;
res ^= f0_load(&g0) ^ f0_store(&g0) ^ f0_reload(&g0);
res ^= g0.f0;
return res;
}
/****/
// PR5591
#pragma pack(push)
#pragma pack(1)
struct __attribute((packed)) s1 {
signed f0 : 10;
signed f1 : 10;
};
#pragma pack(pop)
struct s1 g1 = { 0xdeadbeef, 0xdeadbeef };
int f1_load(struct s1 *a0) {
int size_check[sizeof(struct s1) == 3 ? 1 : -1];
return a0->f1;
}
int f1_store(struct s1 *a0) {
return (a0->f1 = 1234);
}
int f1_reload(struct s1 *a0) {
return (a0->f1 += 1234);
}
// CHECK-OPT: define i64 @test_1()
// CHECK-OPT: ret i64 210
// CHECK-OPT: }
unsigned long long test_1() {
struct s1 g1 = { 0xdeadbeef, 0xdeadbeef };
unsigned long long res = 0;
res ^= g1.f0 ^ g1.f1;
res ^= f1_load(&g1) ^ f1_store(&g1) ^ f1_reload(&g1);
res ^= g1.f0 ^ g1.f1;
return res;
}
/****/
// PR5567
union u2 {
unsigned long long f0 : 3;
};
union u2 g2 = { 0xdeadbeef };
int f2_load(union u2 *a0) {
return a0->f0;
}
int f2_store(union u2 *a0) {
return (a0->f0 = 1234);
}
int f2_reload(union u2 *a0) {
return (a0->f0 += 1234);
}
// CHECK-OPT: define i64 @test_2()
// CHECK-OPT: ret i64 2
// CHECK-OPT: }
unsigned long long test_2() {
union u2 g2 = { 0xdeadbeef };
unsigned long long res = 0;
res ^= g2.f0;
res ^= f2_load(&g2) ^ f2_store(&g2) ^ f2_reload(&g2);
res ^= g2.f0;
return res;
}
/***/
// PR5039
struct s3 {
long long f0 : 32;
long long f1 : 32;
};
struct s3 g3 = { 0xdeadbeef, 0xdeadbeef };
int f3_load(struct s3 *a0) {
a0->f0 = 1;
return a0->f0;
}
int f3_store(struct s3 *a0) {
a0->f0 = 1;
return (a0->f0 = 1234);
}
int f3_reload(struct s3 *a0) {
a0->f0 = 1;
return (a0->f0 += 1234);
}
// CHECK-OPT: define i64 @test_3()
// CHECK-OPT: ret i64 -559039940
// CHECK-OPT: }
unsigned long long test_3() {
struct s3 g3 = { 0xdeadbeef, 0xdeadbeef };
unsigned long long res = 0;
res ^= g3.f0 ^ g3.f1;
res ^= f3_load(&g3) ^ f3_store(&g3) ^ f3_reload(&g3);
res ^= g3.f0 ^ g3.f1;
return res;
}
/***/
// This is a case where the bitfield access will straddle an alignment boundary
// of its underlying type.
struct s4 {
unsigned f0 : 16;
unsigned f1 : 28 __attribute__ ((packed));
};
struct s4 g4 = { 0xdeadbeef, 0xdeadbeef };
int f4_load(struct s4 *a0) {
return a0->f0 ^ a0->f1;
}
int f4_store(struct s4 *a0) {
return (a0->f0 = 1234) ^ (a0->f1 = 5678);
}
int f4_reload(struct s4 *a0) {
return (a0->f0 += 1234) ^ (a0->f1 += 5678);
}
// CHECK-OPT: define i64 @test_4()
// CHECK-OPT: ret i64 4860
// CHECK-OPT: }
unsigned long long test_4() {
struct s4 g4 = { 0xdeadbeef, 0xdeadbeef };
unsigned long long res = 0;
res ^= g4.f0 ^ g4.f1;
res ^= f4_load(&g4) ^ f4_store(&g4) ^ f4_reload(&g4);
res ^= g4.f0 ^ g4.f1;
return res;
}
/***/