| //===- GetElementPtrTypeIterator.h ------------------------------*- C++ -*-===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file implements an iterator for walking through the types indexed by |
| // getelementptr instructions. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef LLVM_IR_GETELEMENTPTRTYPEITERATOR_H |
| #define LLVM_IR_GETELEMENTPTRTYPEITERATOR_H |
| |
| #include "llvm/ADT/ArrayRef.h" |
| #include "llvm/ADT/PointerUnion.h" |
| #include "llvm/IR/DerivedTypes.h" |
| #include "llvm/IR/Operator.h" |
| #include "llvm/IR/User.h" |
| #include "llvm/Support/Casting.h" |
| #include <cassert> |
| #include <cstddef> |
| #include <cstdint> |
| #include <iterator> |
| |
| namespace llvm { |
| |
| template<typename ItTy = User::const_op_iterator> |
| class generic_gep_type_iterator |
| : public std::iterator<std::forward_iterator_tag, Type *, ptrdiff_t> { |
| using super = std::iterator<std::forward_iterator_tag, Type *, ptrdiff_t>; |
| |
| ItTy OpIt; |
| PointerUnion<StructType *, Type *> CurTy; |
| enum : uint64_t { Unbounded = -1ull }; |
| uint64_t NumElements = Unbounded; |
| |
| generic_gep_type_iterator() = default; |
| |
| public: |
| static generic_gep_type_iterator begin(Type *Ty, ItTy It) { |
| generic_gep_type_iterator I; |
| I.CurTy = Ty; |
| I.OpIt = It; |
| return I; |
| } |
| |
| static generic_gep_type_iterator end(ItTy It) { |
| generic_gep_type_iterator I; |
| I.OpIt = It; |
| return I; |
| } |
| |
| bool operator==(const generic_gep_type_iterator& x) const { |
| return OpIt == x.OpIt; |
| } |
| |
| bool operator!=(const generic_gep_type_iterator& x) const { |
| return !operator==(x); |
| } |
| |
| // FIXME: Make this the iterator's operator*() after the 4.0 release. |
| // operator*() had a different meaning in earlier releases, so we're |
| // temporarily not giving this iterator an operator*() to avoid a subtle |
| // semantics break. |
| Type *getIndexedType() const { |
| if (auto *T = CurTy.dyn_cast<Type *>()) |
| return T; |
| return CurTy.get<StructType *>()->getTypeAtIndex(getOperand()); |
| } |
| |
| Value *getOperand() const { return const_cast<Value *>(&**OpIt); } |
| |
| generic_gep_type_iterator& operator++() { // Preincrement |
| Type *Ty = getIndexedType(); |
| if (auto *STy = dyn_cast<SequentialType>(Ty)) { |
| CurTy = STy->getElementType(); |
| NumElements = STy->getNumElements(); |
| } else |
| CurTy = dyn_cast<StructType>(Ty); |
| ++OpIt; |
| return *this; |
| } |
| |
| generic_gep_type_iterator operator++(int) { // Postincrement |
| generic_gep_type_iterator tmp = *this; ++*this; return tmp; |
| } |
| |
| // All of the below API is for querying properties of the "outer type", i.e. |
| // the type that contains the indexed type. Most of the time this is just |
| // the type that was visited immediately prior to the indexed type, but for |
| // the first element this is an unbounded array of the GEP's source element |
| // type, for which there is no clearly corresponding IR type (we've |
| // historically used a pointer type as the outer type in this case, but |
| // pointers will soon lose their element type). |
| // |
| // FIXME: Most current users of this class are just interested in byte |
| // offsets (a few need to know whether the outer type is a struct because |
| // they are trying to replace a constant with a variable, which is only |
| // legal for arrays, e.g. canReplaceOperandWithVariable in SimplifyCFG.cpp); |
| // we should provide a more minimal API here that exposes not much more than |
| // that. |
| |
| bool isStruct() const { return CurTy.is<StructType *>(); } |
| bool isSequential() const { return CurTy.is<Type *>(); } |
| |
| StructType *getStructType() const { return CurTy.get<StructType *>(); } |
| |
| StructType *getStructTypeOrNull() const { |
| return CurTy.dyn_cast<StructType *>(); |
| } |
| |
| bool isBoundedSequential() const { |
| return isSequential() && NumElements != Unbounded; |
| } |
| |
| uint64_t getSequentialNumElements() const { |
| assert(isBoundedSequential()); |
| return NumElements; |
| } |
| }; |
| |
| using gep_type_iterator = generic_gep_type_iterator<>; |
| |
| inline gep_type_iterator gep_type_begin(const User *GEP) { |
| auto *GEPOp = cast<GEPOperator>(GEP); |
| return gep_type_iterator::begin( |
| GEPOp->getSourceElementType(), |
| GEP->op_begin() + 1); |
| } |
| |
| inline gep_type_iterator gep_type_end(const User *GEP) { |
| return gep_type_iterator::end(GEP->op_end()); |
| } |
| |
| inline gep_type_iterator gep_type_begin(const User &GEP) { |
| auto &GEPOp = cast<GEPOperator>(GEP); |
| return gep_type_iterator::begin( |
| GEPOp.getSourceElementType(), |
| GEP.op_begin() + 1); |
| } |
| |
| inline gep_type_iterator gep_type_end(const User &GEP) { |
| return gep_type_iterator::end(GEP.op_end()); |
| } |
| |
| template<typename T> |
| inline generic_gep_type_iterator<const T *> |
| gep_type_begin(Type *Op0, ArrayRef<T> A) { |
| return generic_gep_type_iterator<const T *>::begin(Op0, A.begin()); |
| } |
| |
| template<typename T> |
| inline generic_gep_type_iterator<const T *> |
| gep_type_end(Type * /*Op0*/, ArrayRef<T> A) { |
| return generic_gep_type_iterator<const T *>::end(A.end()); |
| } |
| |
| } // end namespace llvm |
| |
| #endif // LLVM_IR_GETELEMENTPTRTYPEITERATOR_H |