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Diffstat (limited to 'include/llvm/BasicBlock.h')
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1 files changed, 216 insertions, 0 deletions
diff --git a/include/llvm/BasicBlock.h b/include/llvm/BasicBlock.h new file mode 100644 index 0000000..f2722b0 --- /dev/null +++ b/include/llvm/BasicBlock.h @@ -0,0 +1,216 @@ +//===-- llvm/BasicBlock.h - Represent a basic block in the VM ---*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file was developed by the LLVM research group and is distributed under +// the University of Illinois Open Source License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// +// This file contains the declaration of the BasicBlock class. +//===----------------------------------------------------------------------===// + +#ifndef LLVM_BASICBLOCK_H +#define LLVM_BASICBLOCK_H + +#include "llvm/Instruction.h" +#include "llvm/SymbolTableListTraits.h" +#include "llvm/ADT/ilist" +#include "llvm/Support/DataTypes.h" + +namespace llvm { + +class TerminatorInst; +template <class Term, class BB> class SuccIterator; // Successor Iterator +template <class Ptr, class USE_iterator> class PredIterator; + +template<> struct ilist_traits<Instruction> + : public SymbolTableListTraits<Instruction, BasicBlock> { + // createSentinel is used to create a node that marks the end of the list... + static Instruction *createSentinel(); + static void destroySentinel(Instruction *I) { delete I; } + static iplist<Instruction> &getList(BasicBlock *BB); + static ValueSymbolTable *getSymTab(BasicBlock *ItemParent); + static int getListOffset(); +}; + +/// This represents a single basic block in LLVM. A basic block is simply a +/// container of instructions that execute sequentially. Basic blocks are Values +/// because they are referenced by instructions such as branches and switch +/// tables. The type of a BasicBlock is "Type::LabelTy" because the basic block +/// represents a label to which a branch can jump. +/// +/// A well formed basic block is formed of a list of non-terminating +/// instructions followed by a single TerminatorInst instruction. +/// TerminatorInst's may not occur in the middle of basic blocks, and must +/// terminate the blocks. The BasicBlock class allows malformed basic blocks to +/// occur because it may be useful in the intermediate stage of constructing or +/// modifying a program. However, the verifier will ensure that basic blocks +/// are "well formed". +/// @brief LLVM Basic Block Representation +class BasicBlock : public Value { // Basic blocks are data objects also +public: + typedef iplist<Instruction> InstListType; +private : + InstListType InstList; + BasicBlock *Prev, *Next; // Next and Prev links for our intrusive linked list + Function *Parent; + + void setParent(Function *parent); + void setNext(BasicBlock *N) { Next = N; } + void setPrev(BasicBlock *N) { Prev = N; } + friend class SymbolTableListTraits<BasicBlock, Function>; + + BasicBlock(const BasicBlock &); // Do not implement + void operator=(const BasicBlock &); // Do not implement + +public: + /// Instruction iterators... + typedef InstListType::iterator iterator; + typedef InstListType::const_iterator const_iterator; + + /// BasicBlock ctor - If the function parameter is specified, the basic block + /// is automatically inserted at either the end of the function (if + /// InsertBefore is null), or before the specified basic block. + /// + explicit BasicBlock(const std::string &Name = "", Function *Parent = 0, + BasicBlock *InsertBefore = 0); + ~BasicBlock(); + + /// getParent - Return the enclosing method, or null if none + /// + const Function *getParent() const { return Parent; } + Function *getParent() { return Parent; } + + /// use_back - Specialize the methods defined in Value, as we know that an + /// BasicBlock can only be used by Instructions (specifically PHI and terms). + Instruction *use_back() { return cast<Instruction>(*use_begin());} + const Instruction *use_back() const { return cast<Instruction>(*use_begin());} + + /// getTerminator() - If this is a well formed basic block, then this returns + /// a pointer to the terminator instruction. If it is not, then you get a + /// null pointer back. + /// + TerminatorInst *getTerminator(); + const TerminatorInst *const getTerminator() const; + + /// Returns a pointer to the first instructon in this block that is not a + /// PHINode instruction. When adding instruction to the beginning of the + /// basic block, they should be added before the returned value, not before + /// the first instruction, which might be PHI. + /// Returns 0 is there's no non-PHI instruction. + Instruction* getFirstNonPHI(); + + /// removeFromParent - This method unlinks 'this' from the containing + /// function, but does not delete it. + /// + void removeFromParent(); + + /// eraseFromParent - This method unlinks 'this' from the containing function + /// and deletes it. + /// + void eraseFromParent(); + + /// moveBefore - Unlink this basic block from its current function and + /// insert it into the function that MovePos lives in, right before MovePos. + void moveBefore(BasicBlock *MovePos); + + /// moveAfter - Unlink this basic block from its current function and + /// insert it into the function that MovePos lives in, right after MovePos. + void moveAfter(BasicBlock *MovePos); + + + /// getSinglePredecessor - If this basic block has a single predecessor block, + /// return the block, otherwise return a null pointer. + BasicBlock *getSinglePredecessor(); + const BasicBlock *getSinglePredecessor() const { + return const_cast<BasicBlock*>(this)->getSinglePredecessor(); + } + + //===--------------------------------------------------------------------===// + /// Instruction iterator methods + /// + inline iterator begin() { return InstList.begin(); } + inline const_iterator begin() const { return InstList.begin(); } + inline iterator end () { return InstList.end(); } + inline const_iterator end () const { return InstList.end(); } + + inline size_t size() const { return InstList.size(); } + inline bool empty() const { return InstList.empty(); } + inline const Instruction &front() const { return InstList.front(); } + inline Instruction &front() { return InstList.front(); } + inline const Instruction &back() const { return InstList.back(); } + inline Instruction &back() { return InstList.back(); } + + /// getInstList() - Return the underlying instruction list container. You + /// need to access it directly if you want to modify it currently. + /// + const InstListType &getInstList() const { return InstList; } + InstListType &getInstList() { return InstList; } + + virtual void print(std::ostream &OS) const { print(OS, 0); } + void print(std::ostream *OS) const { if (OS) print(*OS); } + void print(std::ostream &OS, AssemblyAnnotationWriter *AAW) const; + + /// Methods for support type inquiry through isa, cast, and dyn_cast: + static inline bool classof(const BasicBlock *) { return true; } + static inline bool classof(const Value *V) { + return V->getValueID() == Value::BasicBlockVal; + } + + /// dropAllReferences() - This function causes all the subinstructions to "let + /// go" of all references that they are maintaining. This allows one to + /// 'delete' a whole class at a time, even though there may be circular + /// references... first all references are dropped, and all use counts go to + /// zero. Then everything is delete'd for real. Note that no operations are + /// valid on an object that has "dropped all references", except operator + /// delete. + /// + void dropAllReferences(); + + /// removePredecessor - This method is used to notify a BasicBlock that the + /// specified Predecessor of the block is no longer able to reach it. This is + /// actually not used to update the Predecessor list, but is actually used to + /// update the PHI nodes that reside in the block. Note that this should be + /// called while the predecessor still refers to this block. + /// + void removePredecessor(BasicBlock *Pred, bool DontDeleteUselessPHIs = false); + + /// splitBasicBlock - This splits a basic block into two at the specified + /// instruction. Note that all instructions BEFORE the specified iterator + /// stay as part of the original basic block, an unconditional branch is added + /// to the original BB, and the rest of the instructions in the BB are moved + /// to the new BB, including the old terminator. The newly formed BasicBlock + /// is returned. This function invalidates the specified iterator. + /// + /// Note that this only works on well formed basic blocks (must have a + /// terminator), and 'I' must not be the end of instruction list (which would + /// cause a degenerate basic block to be formed, having a terminator inside of + /// the basic block). + /// + BasicBlock *splitBasicBlock(iterator I, const std::string &BBName = ""); + + + static unsigned getInstListOffset() { + BasicBlock *Obj = 0; + return unsigned(reinterpret_cast<uintptr_t>(&Obj->InstList)); + } + +private: + // getNext/Prev - Return the next or previous basic block in the list. Access + // these with Function::iterator. + BasicBlock *getNext() { return Next; } + const BasicBlock *getNext() const { return Next; } + BasicBlock *getPrev() { return Prev; } + const BasicBlock *getPrev() const { return Prev; } +}; + +inline int +ilist_traits<Instruction>::getListOffset() { + return BasicBlock::getInstListOffset(); +} + +} // End llvm namespace + +#endif |