X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=include%2Fllvm%2FBasicBlock.h;h=4f4da1ca2fb65929ceb8f1054a49e9dd4dadbec1;hb=b8105651527670cb456eb46dd4346bacd3905361;hp=cf29cbd00e7ba84dedd1010e2bf8b94faaa36ad2;hpb=b00c582b6d40e6b9ff2d1ed4f5eaf7930e792ace;p=oota-llvm.git diff --git a/include/llvm/BasicBlock.h b/include/llvm/BasicBlock.h index cf29cbd00e7..4f4da1ca2fb 100644 --- a/include/llvm/BasicBlock.h +++ b/include/llvm/BasicBlock.h @@ -1,322 +1,240 @@ -//===-- llvm/BasicBlock.h - Represent a basic block in the VM ----*- C++ -*--=// +//===-- llvm/BasicBlock.h - Represent a basic block in the VM ---*- C++ -*-===// // -// This file contains the declaration of the BasicBlock class, which represents -// a single basic block in the VM. +// The LLVM Compiler Infrastructure // -// Note that basic blocks themselves are Def's, because they are referenced -// by instructions like branches and can go in switch tables and stuff... -// -// This may see wierd at first, but it's really pretty cool. :) +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // -// Note that well formed basic blocks are formed of a list of instructions -// followed by a single TerminatorInst instruction. TerminatorInst's may not -// occur in the middle of basic blocks, and must terminate the blocks. -// -// This code allows malformed basic blocks to occur, because it may be useful -// in the intermediate stage of analysis or modification of a program. +// This file contains the declaration of the BasicBlock class. // //===----------------------------------------------------------------------===// #ifndef LLVM_BASICBLOCK_H #define LLVM_BASICBLOCK_H -#include "llvm/Value.h" -#include "llvm/ValueHolder.h" -#include "llvm/Support/GraphTraits.h" -#include "llvm/InstrTypes.h" -#include +#include "llvm/Instruction.h" +#include "llvm/SymbolTableListTraits.h" +#include "llvm/ADT/ilist.h" +#include "llvm/Support/DataTypes.h" + +namespace llvm { -class Instruction; -class Method; class TerminatorInst; -class MachineCodeForBasicBlock; +class LLVMContext; + +template<> struct ilist_traits + : public SymbolTableListTraits { + // createSentinel is used to get hold of a node that marks the end of + // the list... + // The sentinel is relative to this instance, so we use a non-static + // method. + Instruction *createSentinel() const { + // since i(p)lists always publicly derive from the corresponding + // traits, placing a data member in this class will augment i(p)list. + // But since the NodeTy is expected to publicly derive from + // ilist_node, there is a legal viable downcast from it + // to NodeTy. We use this trick to superpose i(p)list with a "ghostly" + // NodeTy, which becomes the sentinel. Dereferencing the sentinel is + // forbidden (save the ilist_node) so no one will ever notice + // the superposition. + return static_cast(&Sentinel); + } + static void destroySentinel(Instruction*) {} -class BasicBlock : public Value { // Basic blocks are data objects also - template class PredIterator; - template class SuccIterator; -public: - typedef ValueHolder InstListType; -private : - InstListType InstList; - MachineCodeForBasicBlock* machineInstrVec; + Instruction *provideInitialHead() const { return createSentinel(); } + Instruction *ensureHead(Instruction*) const { return createSentinel(); } + static void noteHead(Instruction*, Instruction*) {} +private: + mutable ilist_node Sentinel; +}; - friend class ValueHolder; - void setParent(Method *parent); +/// 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 ilist_node { public: - // Instruction iterators... - typedef InstListType::iterator iterator; - typedef InstListType::const_iterator const_iterator; - typedef reverse_iterator const_reverse_iterator; - typedef reverse_iterator reverse_iterator; + typedef iplist InstListType; +private: + InstListType InstList; + Function *Parent; - // Predecessor and successor iterators... - typedef PredIterator pred_iterator; - typedef PredIterator pred_const_iterator; - typedef SuccIterator succ_iterator; - typedef SuccIterator succ_const_iterator; + void setParent(Function *parent); + friend class SymbolTableListTraits; - // Ctor, dtor - BasicBlock(const string &Name = "", Method *Parent = 0); - ~BasicBlock(); + BasicBlock(const BasicBlock &); // Do not implement + void operator=(const BasicBlock &); // Do not implement - // Specialize setName to take care of symbol table majik - virtual void setName(const string &name, SymbolTable *ST = 0); + /// 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); +public: + /// getContext - Get the context in which this basic block lives, + /// or null if it is not currently attached to a function. + LLVMContext *getContext() const; + + /// Instruction iterators... + typedef InstListType::iterator iterator; + typedef InstListType::const_iterator const_iterator; + + /// Create - Creates a new BasicBlock. If the Parent parameter is specified, + /// the basic block is automatically inserted at either the end of the + /// function (if InsertBefore is 0), or before the specified basic block. + static BasicBlock *Create(const std::string &Name = "", Function *Parent = 0, + BasicBlock *InsertBefore = 0) { + return new BasicBlock(Name, Parent, InsertBefore); + } + ~BasicBlock(); - // getParent - Return the enclosing method, or null if none - const Method *getParent() const { return InstList.getParent(); } - Method *getParent() { return InstList.getParent(); } + /// getParent - Return the enclosing method, or null if none + /// + const Function *getParent() const { return Parent; } + Function *getParent() { return Parent; } - // 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. - // + /// use_back - Specialize the methods defined in Value, as we know that an + /// BasicBlock can only be used by Instructions (specifically PHI nodes and + /// terminators). + Instruction *use_back() { return cast(*use_begin());} + const Instruction *use_back() const { return cast(*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; + const TerminatorInst *getTerminator() const; - // Machine code accessor... - inline MachineCodeForBasicBlock& getMachineInstrVec() const { - return *machineInstrVec; + /// 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(); + const Instruction* getFirstNonPHI() const { + return const_cast(this)->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(this)->getSinglePredecessor(); + } + + /// getUniquePredecessor - If this basic block has a unique predecessor block, + /// return the block, otherwise return a null pointer. + /// Note that unique predecessor doesn't mean single edge, there can be + /// multiple edges from the unique predecessor to this block (for example + /// a switch statement with multiple cases having the same destination). + BasicBlock *getUniquePredecessor(); + const BasicBlock *getUniquePredecessor() const { + return const_cast(this)->getUniquePredecessor(); + } + //===--------------------------------------------------------------------===// - // Instruction iterator methods - // + /// 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 reverse_iterator rbegin() { return InstList.rbegin(); } - inline const_reverse_iterator rbegin() const { return InstList.rbegin(); } - inline reverse_iterator rend () { return InstList.rend(); } - inline const_reverse_iterator rend () const { return InstList.rend(); } - - inline unsigned size() const { return InstList.size(); } + 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. - // + 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; } - // Methods for support type inquiry through isa, cast, and dyn_cast: - static inline bool classof(const BasicBlock *BB) { return true; } - static inline bool classof(const Value *V) { - return V->getValueType() == Value::BasicBlockVal; + /// getSublistAccess() - returns pointer to member of instruction list + static iplist BasicBlock::*getSublistAccess(Instruction*) { + return &BasicBlock::InstList; } - // hasConstantPoolReferences() - This predicate is true if there is a - // reference to this basic block in the constant pool for this method. For - // example, if a block is reached through a switch table, that table resides - // in the constant pool, and the basic block is reference from it. - // - bool hasConstantPoolReferences() const; - - // 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); + /// getValueSymbolTable() - returns pointer to symbol table (if any) + ValueSymbolTable *getValueSymbolTable(); - // 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 new 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); - - - //===--------------------------------------------------------------------===// - // Predecessor and Successor Iterators - // - template // Predecessor Iterator - class PredIterator : public std::bidirectional_iterator<_Ptr, ptrdiff_t> { - _Ptr *BB; - _USE_iterator It; - public: - typedef PredIterator<_Ptr,_USE_iterator> _Self; - - inline void advancePastConstPool() { - // TODO: This is bad - // Loop to ignore constant pool references - while (It != BB->use_end() && !isa(*It)) - ++It; - } - - inline PredIterator(_Ptr *bb) : BB(bb), It(bb->use_begin()) { - advancePastConstPool(); - } - inline PredIterator(_Ptr *bb, bool) : BB(bb), It(bb->use_end()) {} - - inline bool operator==(const _Self& x) const { return It == x.It; } - inline bool operator!=(const _Self& x) const { return !operator==(x); } - - inline pointer operator*() const { - return cast(*It)->getParent(); - } - inline pointer *operator->() const { return &(operator*()); } - - inline _Self& operator++() { // Preincrement - ++It; advancePastConstPool(); - return *this; - } - - inline _Self operator++(int) { // Postincrement - _Self tmp = *this; ++*this; return tmp; - } - - inline _Self& operator--() { --It; return *this; } // Predecrement - inline _Self operator--(int) { // Postdecrement - _Self tmp = *this; --*this; return tmp; - } - }; - - inline pred_iterator pred_begin() { return pred_iterator(this); } - inline pred_const_iterator pred_begin() const { - return pred_const_iterator(this); - } - inline pred_iterator pred_end() { return pred_iterator(this, true); } - inline pred_const_iterator pred_end() const { - return pred_const_iterator(this, true); - } - - template // Successor Iterator - class SuccIterator : public std::bidirectional_iterator<_BB, ptrdiff_t> { - const _Term Term; - unsigned idx; - public: - typedef SuccIterator<_Term, _BB> _Self; - // TODO: This can be random access iterator, need operator+ and stuff tho - - inline SuccIterator(_Term T) : Term(T), idx(0) { // begin iterator - assert(T && "getTerminator returned null!"); - } - inline SuccIterator(_Term T, bool) // end iterator - : Term(T), idx(Term->getNumSuccessors()) { - assert(T && "getTerminator returned null!"); - } - - inline bool operator==(const _Self& x) const { return idx == x.idx; } - inline bool operator!=(const _Self& x) const { return !operator==(x); } - - inline pointer operator*() const { return Term->getSuccessor(idx); } - inline pointer operator->() const { return operator*(); } - - inline _Self& operator++() { ++idx; return *this; } // Preincrement - inline _Self operator++(int) { // Postincrement - _Self tmp = *this; ++*this; return tmp; - } - - inline _Self& operator--() { --idx; return *this; } // Predecrement - inline _Self operator--(int) { // Postdecrement - _Self tmp = *this; --*this; return tmp; - } - }; - - inline succ_iterator succ_begin() { return succ_iterator(getTerminator()); } - inline succ_const_iterator succ_begin() const { - return succ_const_iterator(getTerminator()); - } - inline succ_iterator succ_end() {return succ_iterator(getTerminator(), true);} - inline succ_const_iterator succ_end() const { - return succ_const_iterator(getTerminator(), true); - } -}; - - -//===--------------------------------------------------------------------===// -// GraphTraits specializations for basic block graphs (CFGs) -//===--------------------------------------------------------------------===// - -// Provide specializations of GraphTraits to be able to treat a method as a -// graph of basic blocks... - -template <> struct GraphTraits { - typedef BasicBlock NodeType; - typedef BasicBlock::succ_iterator ChildIteratorType; - - static NodeType *getEntryNode(BasicBlock *BB) { return BB; } - static inline ChildIteratorType child_begin(NodeType *N) { - return N->succ_begin(); - } - static inline ChildIteratorType child_end(NodeType *N) { - return N->succ_end(); - } -}; - -template <> struct GraphTraits { - typedef const BasicBlock NodeType; - typedef BasicBlock::succ_const_iterator ChildIteratorType; - - static NodeType *getEntryNode(const BasicBlock *BB) { return BB; } - - static inline ChildIteratorType child_begin(NodeType *N) { - return N->succ_begin(); - } - static inline ChildIteratorType child_end(NodeType *N) { - return N->succ_end(); + /// 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; } -}; -// Provide specializations of GraphTraits to be able to treat a method as a -// graph of basic blocks... and to walk it in inverse order. Inverse order for -// a method is considered to be when traversing the predecessor edges of a BB -// instead of the successor edges. -// -template <> struct GraphTraits > { - typedef BasicBlock NodeType; - typedef BasicBlock::pred_iterator ChildIteratorType; - static NodeType *getEntryNode(Inverse G) { return G.Graph; } - static inline ChildIteratorType child_begin(NodeType *N) { - return N->pred_begin(); - } - static inline ChildIteratorType child_end(NodeType *N) { - return N->pred_end(); - } -}; + /// 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(); -template <> struct GraphTraits > { - typedef const BasicBlock NodeType; - typedef BasicBlock::pred_const_iterator ChildIteratorType; - static NodeType *getEntryNode(Inverse G) { - return G.Graph; - } - static inline ChildIteratorType child_begin(NodeType *N) { - return N->pred_begin(); - } - static inline ChildIteratorType child_end(NodeType *N) { - return N->pred_end(); - } + /// 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 = ""); }; +} // End llvm namespace #endif