forked from OSchip/llvm-project
Anders Carlsson
parent
67829f6493
commit
1726aaa4fc
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@ -467,188 +467,12 @@ public:
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return llvm::ConstantArray::get(AType, Elts);
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}
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void InsertBitfieldIntoStruct(std::vector<llvm::Constant*>& Elts,
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FieldDecl* Field, Expr* E) {
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// Calculate the value to insert
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llvm::Constant *C = CGM.EmitConstantExpr(E, Field->getType(), CGF);
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if (!C)
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return;
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llvm::ConstantInt *CI = dyn_cast<llvm::ConstantInt>(C);
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if (!CI) {
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CGM.ErrorUnsupported(E, "bitfield initialization");
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return;
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}
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llvm::APInt V = CI->getValue();
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// Calculate information about the relevant field
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const llvm::Type* Ty = CI->getType();
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const llvm::TargetData &TD = CGM.getTypes().getTargetData();
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unsigned size = TD.getTypeAllocSizeInBits(Ty);
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CodeGenTypes::BitFieldInfo Info = CGM.getTypes().getBitFieldInfo(Field);
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unsigned FieldOffset = Info.FieldNo * size;
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FieldOffset += Info.Start;
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// Find where to start the insertion
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// FIXME: This is O(n^2) in the number of bit-fields!
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// FIXME: This won't work if the struct isn't completely packed!
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unsigned offset = 0, i = 0;
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while (offset < (FieldOffset & -8))
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offset += TD.getTypeAllocSizeInBits(Elts[i++]->getType());
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// Advance over 0 sized elements (must terminate in bounds since
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// the bitfield must have a size).
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while (TD.getTypeAllocSizeInBits(Elts[i]->getType()) == 0)
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++i;
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// Promote the size of V if necessary
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// FIXME: This should never occur, but currently it can because initializer
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// constants are cast to bool, and because clang is not enforcing bitfield
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// width limits.
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if (Info.Size > V.getBitWidth())
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V.zext(Info.Size);
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// Insert the bits into the struct
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// FIXME: This algorthm is only correct on X86!
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// FIXME: THis algorthm assumes bit-fields only have byte-size elements!
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unsigned bitsToInsert = Info.Size;
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unsigned curBits = std::min(8 - (FieldOffset & 7), bitsToInsert);
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unsigned byte = V.getLoBits(curBits).getZExtValue() << (FieldOffset & 7);
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do {
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llvm::Constant* byteC =
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llvm::ConstantInt::get(llvm::Type::Int8Ty, byte);
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Elts[i] = llvm::ConstantExpr::getOr(Elts[i], byteC);
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++i;
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V = V.lshr(curBits);
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bitsToInsert -= curBits;
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if (!bitsToInsert)
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break;
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curBits = bitsToInsert > 8 ? 8 : bitsToInsert;
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byte = V.getLoBits(curBits).getZExtValue();
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} while (true);
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}
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llvm::Constant *EmitStructInitialization(InitListExpr *ILE) {
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return ConstStructBuilder::BuildStruct(CGM, CGF, ILE);
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// FIXME: Remove the old struct builder once we're sure that the new one
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// works well enough!
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const llvm::StructType *SType =
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cast<llvm::StructType>(ConvertType(ILE->getType()));
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RecordDecl *RD = ILE->getType()->getAs<RecordType>()->getDecl();
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std::vector<llvm::Constant*> Elts;
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// Initialize the whole structure to zero.
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// FIXME: This doesn't handle member pointers correctly!
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for (unsigned i = 0; i < SType->getNumElements(); ++i) {
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const llvm::Type *FieldTy = SType->getElementType(i);
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Elts.push_back(llvm::Constant::getNullValue(FieldTy));
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}
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// Copy initializer elements. Skip padding fields.
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unsigned EltNo = 0; // Element no in ILE
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bool RewriteType = false;
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for (RecordDecl::field_iterator Field = RD->field_begin(),
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FieldEnd = RD->field_end();
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EltNo < ILE->getNumInits() && Field != FieldEnd; ++Field) {
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if (Field->isBitField()) {
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if (!Field->getIdentifier())
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continue;
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InsertBitfieldIntoStruct(Elts, *Field, ILE->getInit(EltNo));
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} else {
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unsigned FieldNo = CGM.getTypes().getLLVMFieldNo(*Field);
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llvm::Constant *C = CGM.EmitConstantExpr(ILE->getInit(EltNo),
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Field->getType(), CGF);
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if (!C) return 0;
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RewriteType |= (C->getType() != Elts[FieldNo]->getType());
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Elts[FieldNo] = C;
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}
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EltNo++;
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}
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if (RewriteType) {
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// FIXME: Make this work for non-packed structs
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assert(SType->isPacked() && "Cannot recreate unpacked structs");
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std::vector<const llvm::Type*> Types;
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for (unsigned i = 0; i < Elts.size(); ++i)
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Types.push_back(Elts[i]->getType());
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SType = llvm::StructType::get(Types, true);
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}
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return llvm::ConstantStruct::get(SType, Elts);
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}
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llvm::Constant *EmitUnion(llvm::Constant *C, const llvm::Type *Ty) {
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if (!C)
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return 0;
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// Build a struct with the union sub-element as the first member,
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// and padded to the appropriate size
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std::vector<llvm::Constant*> Elts;
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std::vector<const llvm::Type*> Types;
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Elts.push_back(C);
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Types.push_back(C->getType());
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unsigned CurSize = CGM.getTargetData().getTypeAllocSize(C->getType());
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unsigned TotalSize = CGM.getTargetData().getTypeAllocSize(Ty);
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assert(CurSize <= TotalSize && "Union size mismatch!");
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if (unsigned NumPadBytes = TotalSize - CurSize) {
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const llvm::Type *Ty = llvm::Type::Int8Ty;
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if (NumPadBytes > 1)
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Ty = llvm::ArrayType::get(Ty, NumPadBytes);
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Elts.push_back(llvm::Constant::getNullValue(Ty));
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Types.push_back(Ty);
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}
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llvm::StructType* STy = llvm::StructType::get(Types, false);
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return llvm::ConstantStruct::get(STy, Elts);
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}
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llvm::Constant *EmitUnionInitialization(InitListExpr *ILE) {
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return ConstStructBuilder::BuildStruct(CGM, CGF, ILE);
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const llvm::Type *Ty = ConvertType(ILE->getType());
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FieldDecl* curField = ILE->getInitializedFieldInUnion();
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if (!curField) {
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// There's no field to initialize, so value-initialize the union.
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#ifndef NDEBUG
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// Make sure that it's really an empty and not a failure of
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// semantic analysis.
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RecordDecl *RD = ILE->getType()->getAs<RecordType>()->getDecl();
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for (RecordDecl::field_iterator Field = RD->field_begin(),
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FieldEnd = RD->field_end();
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Field != FieldEnd; ++Field)
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assert(Field->isUnnamedBitfield() && "Only unnamed bitfields allowed");
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#endif
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return llvm::Constant::getNullValue(Ty);
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}
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if (curField->isBitField()) {
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// Create a dummy struct for bit-field insertion
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unsigned NumElts = CGM.getTargetData().getTypeAllocSize(Ty);
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llvm::Constant* NV =
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llvm::Constant::getNullValue(llvm::Type::Int8Ty);
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std::vector<llvm::Constant*> Elts(NumElts, NV);
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InsertBitfieldIntoStruct(Elts, curField, ILE->getInit(0));
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const llvm::ArrayType *RetTy =
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llvm::ArrayType::get(NV->getType(), NumElts);
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return llvm::ConstantArray::get(RetTy, Elts);
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}
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llvm::Constant *InitElem;
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if (ILE->getNumInits() > 0) {
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Expr *Init = ILE->getInit(0);
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InitElem = CGM.EmitConstantExpr(Init, Init->getType(), CGF);
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} else {
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InitElem = CGM.EmitNullConstant(curField->getType());
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}
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return EmitUnion(InitElem, Ty);
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}
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llvm::Constant *EmitVectorInitialization(InitListExpr *ILE) {
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