| //===-- TransformInternals.cpp - Implement shared functions for transforms --=// |
| // |
| // This file defines shared functions used by the different components of the |
| // Transforms library. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "TransformInternals.h" |
| #include "llvm/Method.h" |
| #include "llvm/Type.h" |
| #include "llvm/ConstantVals.h" |
| #include "llvm/Analysis/Expressions.h" |
| #include "llvm/iOther.h" |
| #include <algorithm> |
| |
| // TargetData Hack: Eventually we will have annotations given to us by the |
| // backend so that we know stuff about type size and alignments. For now |
| // though, just use this, because it happens to match the model that GCC uses. |
| // |
| const TargetData TD("LevelRaise: Should be GCC though!"); |
| |
| // ReplaceInstWithValue - Replace all uses of an instruction (specified by BI) |
| // with a value, then remove and delete the original instruction. |
| // |
| void ReplaceInstWithValue(BasicBlock::InstListType &BIL, |
| BasicBlock::iterator &BI, Value *V) { |
| Instruction *I = *BI; |
| // Replaces all of the uses of the instruction with uses of the value |
| I->replaceAllUsesWith(V); |
| |
| // Remove the unneccesary instruction now... |
| BIL.remove(BI); |
| |
| // Make sure to propogate a name if there is one already... |
| if (I->hasName() && !V->hasName()) |
| V->setName(I->getName(), BIL.getParent()->getSymbolTable()); |
| |
| // Remove the dead instruction now... |
| delete I; |
| } |
| |
| |
| // ReplaceInstWithInst - Replace the instruction specified by BI with the |
| // instruction specified by I. The original instruction is deleted and BI is |
| // updated to point to the new instruction. |
| // |
| void ReplaceInstWithInst(BasicBlock::InstListType &BIL, |
| BasicBlock::iterator &BI, Instruction *I) { |
| assert(I->getParent() == 0 && |
| "ReplaceInstWithInst: Instruction already inserted into basic block!"); |
| |
| // Insert the new instruction into the basic block... |
| BI = BIL.insert(BI, I)+1; |
| |
| // Replace all uses of the old instruction, and delete it. |
| ReplaceInstWithValue(BIL, BI, I); |
| |
| // Reexamine the instruction just inserted next time around the cleanup pass |
| // loop. |
| --BI; |
| } |
| |
| void ReplaceInstWithInst(Instruction *From, Instruction *To) { |
| BasicBlock *BB = From->getParent(); |
| BasicBlock::InstListType &BIL = BB->getInstList(); |
| BasicBlock::iterator BI = find(BIL.begin(), BIL.end(), From); |
| assert(BI != BIL.end() && "Inst not in it's parents BB!"); |
| ReplaceInstWithInst(BIL, BI, To); |
| } |
| |
| |
| |
| // getStructOffsetType - Return a vector of offsets that are to be used to index |
| // into the specified struct type to get as close as possible to index as we |
| // can. Note that it is possible that we cannot get exactly to Offset, in which |
| // case we update offset to be the offset we actually obtained. The resultant |
| // leaf type is returned. |
| // |
| // If StopEarly is set to true (the default), the first object with the |
| // specified type is returned, even if it is a struct type itself. In this |
| // case, this routine will not drill down to the leaf type. Set StopEarly to |
| // false if you want a leaf |
| // |
| const Type *getStructOffsetType(const Type *Ty, unsigned &Offset, |
| vector<Value*> &Offsets, |
| bool StopEarly = true) { |
| if (Offset == 0 && StopEarly && !Offsets.empty()) |
| return Ty; // Return the leaf type |
| |
| unsigned ThisOffset; |
| const Type *NextType; |
| if (const StructType *STy = dyn_cast<StructType>(Ty)) { |
| assert(Offset < TD.getTypeSize(STy) && "Offset not in composite!"); |
| const StructLayout *SL = TD.getStructLayout(STy); |
| |
| // This loop terminates always on a 0 <= i < MemberOffsets.size() |
| unsigned i; |
| for (i = 0; i < SL->MemberOffsets.size()-1; ++i) |
| if (Offset >= SL->MemberOffsets[i] && Offset < SL->MemberOffsets[i+1]) |
| break; |
| |
| assert(Offset >= SL->MemberOffsets[i] && |
| (i == SL->MemberOffsets.size()-1 || Offset <SL->MemberOffsets[i+1])); |
| |
| // Make sure to save the current index... |
| Offsets.push_back(ConstantUInt::get(Type::UByteTy, i)); |
| ThisOffset = SL->MemberOffsets[i]; |
| NextType = STy->getElementTypes()[i]; |
| } else if (const ArrayType *ATy = dyn_cast<ArrayType>(Ty)) { |
| assert(Offset < TD.getTypeSize(ATy) && "Offset not in composite!"); |
| |
| NextType = ATy->getElementType(); |
| unsigned ChildSize = TD.getTypeSize(NextType); |
| Offsets.push_back(ConstantUInt::get(Type::UIntTy, Offset/ChildSize)); |
| ThisOffset = (Offset/ChildSize)*ChildSize; |
| } else { |
| Offset = 0; // Return the offset that we were able to acheive |
| return Ty; // Return the leaf type |
| } |
| |
| unsigned SubOffs = Offset - ThisOffset; |
| const Type *LeafTy = getStructOffsetType(NextType, SubOffs, Offsets); |
| Offset = ThisOffset + SubOffs; |
| return LeafTy; |
| } |
| |
| // ConvertableToGEP - This function returns true if the specified value V is |
| // a valid index into a pointer of type Ty. If it is valid, Idx is filled in |
| // with the values that would be appropriate to make this a getelementptr |
| // instruction. The type returned is the root type that the GEP would point to |
| // |
| const Type *ConvertableToGEP(const Type *Ty, Value *OffsetVal, |
| vector<Value*> &Indices, |
| BasicBlock::iterator *BI = 0) { |
| const CompositeType *CompTy = dyn_cast<CompositeType>(Ty); |
| if (CompTy == 0) return 0; |
| |
| // See if the cast is of an integer expression that is either a constant, |
| // or a value scaled by some amount with a possible offset. |
| // |
| analysis::ExprType Expr = analysis::ClassifyExpression(OffsetVal); |
| |
| // Get the offset and scale now... |
| unsigned Offset = 0, Scale = Expr.Var != 0; |
| |
| // Get the offset value if it exists... |
| if (Expr.Offset) { |
| int Val = getConstantValue(Expr.Offset); |
| if (Val < 0) return false; // Don't mess with negative offsets |
| Offset = (unsigned)Val; |
| } |
| |
| // Get the scale value if it exists... |
| if (Expr.Scale) { |
| int Val = getConstantValue(Expr.Scale); |
| if (Val < 0) return false; // Don't mess with negative scales |
| Scale = (unsigned)Val; |
| } |
| |
| // Loop over the Scale and Offset values, filling in the Indices vector for |
| // our final getelementptr instruction. |
| // |
| const Type *NextTy = CompTy; |
| do { |
| if (!isa<CompositeType>(NextTy)) |
| return 0; // Type must not be ready for processing... |
| CompTy = cast<CompositeType>(NextTy); |
| |
| if (const StructType *StructTy = dyn_cast<StructType>(CompTy)) { |
| const StructLayout *SL = TD.getStructLayout(StructTy); |
| unsigned ActualOffset = Offset; |
| NextTy = getStructOffsetType(StructTy, ActualOffset, Indices); |
| if (StructTy == NextTy && ActualOffset == 0) return 0; // No progress. :( |
| Offset -= ActualOffset; |
| } else { |
| const Type *ElTy = cast<SequentialType>(CompTy)->getElementType(); |
| if (!ElTy->isSized()) return 0; // Type is unreasonable... escape! |
| unsigned ElSize = TD.getTypeSize(ElTy); |
| |
| // See if the user is indexing into a different cell of this array... |
| if (Scale && Scale >= ElSize) { |
| // A scale n*ElSize might occur if we are not stepping through |
| // array by one. In this case, we will have to insert math to munge |
| // the index. |
| // |
| unsigned ScaleAmt = Scale/ElSize; |
| if (Scale-ScaleAmt*ElSize) |
| return 0; // Didn't scale by a multiple of element size, bail out |
| Scale = 0; // Scale is consumed |
| |
| unsigned Index = Offset/ElSize; // is zero unless Offset > ElSize |
| Offset -= Index*ElSize; // Consume part of the offset |
| |
| if (BI) { // Generate code? |
| BasicBlock *BB = (**BI)->getParent(); |
| if (Expr.Var->getType() != Type::UIntTy) { |
| CastInst *IdxCast = new CastInst(Expr.Var, Type::UIntTy); |
| if (Expr.Var->hasName()) |
| IdxCast->setName(Expr.Var->getName()+"-idxcast"); |
| *BI = BB->getInstList().insert(*BI, IdxCast)+1; |
| Expr.Var = IdxCast; |
| } |
| |
| if (ScaleAmt && ScaleAmt != 1) { |
| // If we have to scale up our index, do so now |
| Value *ScaleAmtVal = ConstantUInt::get(Type::UIntTy, ScaleAmt); |
| Instruction *Scaler = BinaryOperator::create(Instruction::Mul, |
| Expr.Var,ScaleAmtVal); |
| if (Expr.Var->hasName()) |
| Scaler->setName(Expr.Var->getName()+"-scale"); |
| |
| *BI = BB->getInstList().insert(*BI, Scaler)+1; |
| Expr.Var = Scaler; |
| } |
| |
| if (Index) { // Add an offset to the index |
| Value *IndexAmt = ConstantUInt::get(Type::UIntTy, Index); |
| Instruction *Offseter = BinaryOperator::create(Instruction::Add, |
| Expr.Var, IndexAmt); |
| if (Expr.Var->hasName()) |
| Offseter->setName(Expr.Var->getName()+"-offset"); |
| *BI = BB->getInstList().insert(*BI, Offseter)+1; |
| Expr.Var = Offseter; |
| } |
| } |
| |
| Indices.push_back(Expr.Var); |
| } else if (Offset >= ElSize) { |
| // Calculate the index that we are entering into the array cell with |
| unsigned Index = Offset/ElSize; |
| Indices.push_back(ConstantUInt::get(Type::UIntTy, Index)); |
| Offset -= Index*ElSize; // Consume part of the offset |
| |
| } else if (!isa<PointerType>(CompTy) || CompTy == Ty) { |
| // Must be indexing a small amount into the first cell of the array |
| // Just index into element zero of the array here. |
| // |
| Indices.push_back(ConstantUInt::get(Type::UIntTy, 0)); |
| } else { |
| return 0; // Hrm. wierd, can't handle this case. Bail |
| } |
| NextTy = ElTy; |
| } |
| } while (Offset || Scale); // Go until we're done! |
| |
| return NextTy; |
| } |