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-rw-r--r--lib/CodeGen/CGExpr.cpp242
1 files changed, 88 insertions, 154 deletions
diff --git a/lib/CodeGen/CGExpr.cpp b/lib/CodeGen/CGExpr.cpp
index f0ee2343d4..94bc81c8f4 100644
--- a/lib/CodeGen/CGExpr.cpp
+++ b/lib/CodeGen/CGExpr.cpp
@@ -1155,72 +1155,30 @@ RValue CodeGenFunction::EmitLoadOfBitfieldLValue(LValue LV) {
// Get the output type.
llvm::Type *ResLTy = ConvertType(LV.getType());
- unsigned ResSizeInBits = CGM.getDataLayout().getTypeSizeInBits(ResLTy);
-
- // Compute the result as an OR of all of the individual component accesses.
- llvm::Value *Res = 0;
- for (unsigned i = 0, e = Info.getNumComponents(); i != e; ++i) {
- const CGBitFieldInfo::AccessInfo &AI = Info.getComponent(i);
- CharUnits AccessAlignment = AI.AccessAlignment;
- if (!LV.getAlignment().isZero())
- AccessAlignment = std::min(AccessAlignment, LV.getAlignment());
-
- // Get the field pointer.
- llvm::Value *Ptr = LV.getBitFieldBaseAddr();
-
- // 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");
-
- // Offset by the byte offset, if used.
- if (!AI.FieldByteOffset.isZero()) {
- Ptr = EmitCastToVoidPtr(Ptr);
- Ptr = Builder.CreateConstGEP1_32(Ptr, AI.FieldByteOffset.getQuantity(),
- "bf.field.offs");
- }
-
- // Cast to the access type.
- llvm::Type *PTy = llvm::Type::getIntNPtrTy(getLLVMContext(), AI.AccessWidth,
- CGM.getContext().getTargetAddressSpace(LV.getType()));
- Ptr = Builder.CreateBitCast(Ptr, PTy);
-
- // Perform the load.
- llvm::LoadInst *Load = Builder.CreateLoad(Ptr, LV.isVolatileQualified());
- Load->setAlignment(AccessAlignment.getQuantity());
-
- // 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.CreateAnd(Val, llvm::APInt::getLowBitsSet(AI.AccessWidth,
- AI.TargetBitWidth),
- "bf.clear");
-
- // Extend or truncate to the target size.
- if (AI.AccessWidth < ResSizeInBits)
- Val = Builder.CreateZExt(Val, ResLTy);
- else if (AI.AccessWidth > ResSizeInBits)
- Val = Builder.CreateTrunc(Val, ResLTy);
- // Shift into place, and OR into the result.
- if (AI.TargetBitOffset)
- Val = Builder.CreateShl(Val, AI.TargetBitOffset);
- Res = Res ? Builder.CreateOr(Res, Val) : Val;
- }
-
- // If the bit-field is signed, perform the sign-extension.
- //
- // 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();
- if (ExtraBits)
- Res = Builder.CreateAShr(Builder.CreateShl(Res, ExtraBits),
- ExtraBits, "bf.val.sext");
+ llvm::Value *Ptr = LV.getBitFieldAddr();
+ llvm::Value *Val = Builder.CreateLoad(Ptr, LV.isVolatileQualified(),
+ "bf.load");
+ cast<llvm::LoadInst>(Val)->setAlignment(Info.StorageAlignment);
+
+ if (Info.IsSigned) {
+ assert((Info.Offset + Info.Size) <= Info.StorageSize);
+ unsigned HighBits = Info.StorageSize - Info.Offset - Info.Size;
+ if (HighBits)
+ Val = Builder.CreateShl(Val, HighBits, "bf.shl");
+ if (Info.Offset + HighBits)
+ Val = Builder.CreateAShr(Val, Info.Offset + HighBits, "bf.ashr");
+ } else {
+ if (Info.Offset)
+ Val = Builder.CreateLShr(Val, Info.Offset, "bf.lshr");
+ if (Info.Offset + Info.Size < Info.StorageSize)
+ Val = Builder.CreateAnd(Val, llvm::APInt::getLowBitsSet(Info.StorageSize,
+ Info.Size),
+ "bf.clear");
}
+ Val = Builder.CreateIntCast(Val, ResLTy, Info.IsSigned, "bf.cast");
- return RValue::get(Res);
+ return RValue::get(Val);
}
// If this is a reference to a subset of the elements of a vector, create an
@@ -1350,106 +1308,71 @@ void CodeGenFunction::EmitStoreThroughLValue(RValue Src, LValue Dst, bool isInit
void CodeGenFunction::EmitStoreThroughBitfieldLValue(RValue Src, LValue Dst,
llvm::Value **Result) {
const CGBitFieldInfo &Info = Dst.getBitFieldInfo();
-
- // Get the output type.
llvm::Type *ResLTy = ConvertTypeForMem(Dst.getType());
- unsigned ResSizeInBits = CGM.getDataLayout().getTypeSizeInBits(ResLTy);
+ llvm::Value *Ptr = Dst.getBitFieldAddr();
// Get the source value, truncated to the width of the bit-field.
llvm::Value *SrcVal = Src.getScalarVal();
- if (hasBooleanRepresentation(Dst.getType()))
- SrcVal = Builder.CreateIntCast(SrcVal, ResLTy, /*IsSigned=*/false);
-
- SrcVal = Builder.CreateAnd(SrcVal, llvm::APInt::getLowBitsSet(ResSizeInBits,
- Info.getSize()),
- "bf.value");
-
- // Return the new value of the bit-field, if requested.
- if (Result) {
- // Cast back to the proper type for result.
- llvm::Type *SrcTy = Src.getScalarVal()->getType();
- llvm::Value *ReloadVal = Builder.CreateIntCast(SrcVal, 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");
- }
+ // Cast the source to the storage type and shift it into place.
+ SrcVal = Builder.CreateIntCast(SrcVal,
+ Ptr->getType()->getPointerElementType(),
+ /*IsSigned=*/false);
+ llvm::Value *MaskedVal = SrcVal;
+
+ // See if there are other bits in the bitfield's storage we'll need to load
+ // and mask together with source before storing.
+ if (Info.StorageSize != Info.Size) {
+ assert(Info.StorageSize > Info.Size && "Invalid bitfield size.");
+ llvm::Value *Val = Builder.CreateLoad(Ptr, Dst.isVolatileQualified(),
+ "bf.load");
+ cast<llvm::LoadInst>(Val)->setAlignment(Info.StorageAlignment);
+
+ // Mask the source value as needed.
+ if (!hasBooleanRepresentation(Dst.getType()))
+ SrcVal = Builder.CreateAnd(SrcVal,
+ llvm::APInt::getLowBitsSet(Info.StorageSize,
+ Info.Size),
+ "bf.value");
+ MaskedVal = SrcVal;
+ if (Info.Offset)
+ SrcVal = Builder.CreateShl(SrcVal, Info.Offset, "bf.shl");
+
+ // Mask out the original value.
+ Val = Builder.CreateAnd(Val,
+ ~llvm::APInt::getBitsSet(Info.StorageSize,
+ Info.Offset,
+ Info.Offset + Info.Size),
+ "bf.clear");
- *Result = ReloadVal;
+ // Or together the unchanged values and the source value.
+ SrcVal = Builder.CreateOr(Val, SrcVal, "bf.set");
+ } else {
+ assert(Info.Offset == 0);
}
- // 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);
- CharUnits AccessAlignment = AI.AccessAlignment;
- if (!Dst.getAlignment().isZero())
- AccessAlignment = std::min(AccessAlignment, Dst.getAlignment());
-
- // Get the field pointer.
- llvm::Value *Ptr = Dst.getBitFieldBaseAddr();
- unsigned addressSpace =
- cast<llvm::PointerType>(Ptr->getType())->getAddressSpace();
-
- // 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");
-
- // Offset by the byte offset, if used.
- if (!AI.FieldByteOffset.isZero()) {
- Ptr = EmitCastToVoidPtr(Ptr);
- Ptr = Builder.CreateConstGEP1_32(Ptr, AI.FieldByteOffset.getQuantity(),
- "bf.field.offs");
- }
+ // Write the new value back out.
+ llvm::StoreInst *Store = Builder.CreateStore(SrcVal, Ptr,
+ Dst.isVolatileQualified());
+ Store->setAlignment(Info.StorageAlignment);
- // Cast to the access type.
- llvm::Type *AccessLTy =
- llvm::Type::getIntNTy(getLLVMContext(), AI.AccessWidth);
-
- llvm::Type *PTy = AccessLTy->getPointerTo(addressSpace);
- Ptr = Builder.CreateBitCast(Ptr, PTy);
-
- // Extract the piece of the bit-field value to write in this access, limited
- // to the values that are part of this access.
- llvm::Value *Val = SrcVal;
- if (AI.TargetBitOffset)
- Val = Builder.CreateLShr(Val, AI.TargetBitOffset);
- Val = Builder.CreateAnd(Val, llvm::APInt::getLowBitsSet(ResSizeInBits,
- AI.TargetBitWidth));
-
- // Extend or truncate to the access size.
- if (ResSizeInBits < AI.AccessWidth)
- Val = Builder.CreateZExt(Val, AccessLTy);
- else if (ResSizeInBits > AI.AccessWidth)
- Val = Builder.CreateTrunc(Val, AccessLTy);
-
- // Shift into the position in memory.
- if (AI.FieldBitStart)
- Val = Builder.CreateShl(Val, AI.FieldBitStart);
-
- // 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());
- Load->setAlignment(AccessAlignment.getQuantity());
-
- // 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(Builder.CreateAnd(Load, InvMask), Val);
+ // Return the new value of the bit-field, if requested.
+ if (Result) {
+ llvm::Value *ResultVal = MaskedVal;
+
+ // Sign extend the value if needed.
+ if (Info.IsSigned) {
+ assert(Info.Size <= Info.StorageSize);
+ unsigned HighBits = Info.StorageSize - Info.Size;
+ if (HighBits) {
+ ResultVal = Builder.CreateShl(ResultVal, HighBits, "bf.result.shl");
+ ResultVal = Builder.CreateAShr(ResultVal, HighBits, "bf.result.ashr");
+ }
}
- // Write the value.
- llvm::StoreInst *Store = Builder.CreateStore(Val, Ptr,
- Dst.isVolatileQualified());
- Store->setAlignment(AccessAlignment.getQuantity());
+ ResultVal = Builder.CreateIntCast(ResultVal, ResLTy, Info.IsSigned,
+ "bf.result.cast");
+ *Result = ResultVal;
}
}
@@ -2333,10 +2256,21 @@ LValue CodeGenFunction::EmitLValueForField(LValue base,
const CGRecordLayout &RL =
CGM.getTypes().getCGRecordLayout(field->getParent());
const CGBitFieldInfo &Info = RL.getBitFieldInfo(field);
+ llvm::Value *Addr = base.getAddress();
+ unsigned Idx = RL.getLLVMFieldNo(field);
+ if (Idx != 0)
+ // For structs, we GEP to the field that the record layout suggests.
+ Addr = Builder.CreateStructGEP(Addr, Idx, field->getName());
+ // Get the access type.
+ llvm::Type *PtrTy = llvm::Type::getIntNPtrTy(
+ getLLVMContext(), Info.StorageSize,
+ CGM.getContext().getTargetAddressSpace(base.getType()));
+ if (Addr->getType() != PtrTy)
+ Addr = Builder.CreateBitCast(Addr, PtrTy);
+
QualType fieldType =
field->getType().withCVRQualifiers(base.getVRQualifiers());
- return LValue::MakeBitfield(base.getAddress(), Info, fieldType,
- base.getAlignment());
+ return LValue::MakeBitfield(Addr, Info, fieldType, base.getAlignment());
}
const RecordDecl *rec = field->getParent();
generated by cgit v1.2.3-18-g5258 (git 2.32.0) at 2025-07-25 12:22:12 +0000