-//===-- 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 was developed by the LLVM research group and 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" // Get the definition of Value
-#include "llvm/ValueHolder.h"
-#include "llvm/InstrTypes.h"
-#include <list>
+#include "llvm/Instruction.h"
+#include "llvm/SymbolTableListTraits.h"
+#include "llvm/ADT/ilist"
+#include "llvm/Support/DataTypes.h"
-class Instruction;
-class Method;
-class BasicBlock;
-class TerminatorInst;
+namespace llvm {
-typedef UseTy<BasicBlock> BasicBlockUse;
+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 ValueHolder<Instruction, BasicBlock> InstListType;
+ typedef iplist<Instruction> InstListType;
private :
InstListType InstList;
+ BasicBlock *Prev, *Next; // Next and Prev links for our intrusive linked list
+ Function *Parent;
- friend class ValueHolder<BasicBlock,Method>;
- void setParent(Method *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:
- BasicBlock(const string &Name = "", Method *Parent = 0);
+ /// 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();
- // Specialize setName to take care of symbol table majik
- virtual void setName(const string &name);
-
- const Method *getParent() const { return (const Method*)InstList.getParent();}
- Method *getParent() { return (Method*)InstList.getParent(); }
+ /// 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 *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; }
- // 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;
-
- // 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.
- //
+ 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();
- // 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(InstListType::iterator I);
-
- //===--------------------------------------------------------------------===//
- // Predecessor iterator code
- //===--------------------------------------------------------------------===//
- //
- // This is used to figure out what basic blocks we could be coming from.
- //
-
- // Forward declare iterator class template...
- template <class _Ptr, class _USE_iterator> class PredIterator;
-
- typedef PredIterator<BasicBlock*, use_iterator> pred_iterator;
- typedef PredIterator<const BasicBlock*,
- use_const_iterator> pred_const_iterator;
-
- inline pred_iterator pred_begin() ;
- inline pred_const_iterator pred_begin() const;
- inline pred_iterator pred_end() ;
- inline pred_const_iterator pred_end() const;
-
- //===--------------------------------------------------------------------===//
- // Successor iterator code
- //===--------------------------------------------------------------------===//
- //
- // This is used to figure out what basic blocks we could be going to...
- //
-
- // Forward declare iterator class template...
- template <class _Term, class _BB> class SuccIterator;
-
- typedef SuccIterator<TerminatorInst*, BasicBlock*> succ_iterator;
- typedef SuccIterator<const TerminatorInst*,
- const BasicBlock*> succ_const_iterator;
-
- inline succ_iterator succ_begin() ;
- inline succ_const_iterator succ_begin() const;
- inline succ_iterator succ_end() ;
- inline succ_const_iterator succ_end() const;
-
- //===--------------------------------------------------------------------===//
- // END of interesting code...
- //===--------------------------------------------------------------------===//
- //
- // Thank god C++ compilers are good at stomping out tons of templated code...
- //
- template <class _Ptr, class _USE_iterator> // Predecessor Iterator
- class PredIterator {
- const _Ptr ThisBB;
- _USE_iterator It;
- public:
- typedef PredIterator<_Ptr,_USE_iterator> _Self;
-
- typedef bidirectional_iterator_tag iterator_category;
- typedef _Ptr pointer;
-
- inline void advancePastConstPool() {
- // Loop to ignore constant pool references
- while (It != ThisBB->use_end() &&
- ((*It)->getValueType() != Value::InstructionVal))
- ++It;
- }
-
- inline PredIterator(_Ptr BB) : ThisBB(BB), It(BB->use_begin()) {
- advancePastConstPool();
- }
- inline PredIterator(_Ptr BB, bool) : ThisBB(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 {
- assert ((*It)->getValueType() == Value::InstructionVal);
- return ((Instruction *)(*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;
- }
- };
-
- template <class _Term, class _BB> // Successor Iterator
- class SuccIterator {
- const _Term Term;
- unsigned idx;
- public:
- typedef SuccIterator<_Term, _BB> _Self;
- typedef forward_iterator_tag iterator_category;
- typedef _BB pointer;
-
- inline SuccIterator(_Term T) : Term(T), idx(0) {} // begin iterator
- inline SuccIterator(_Term T, bool)
- : Term(T), idx(Term->getNumSuccessors()) {} // end iterator
-
- 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;
- }
- };
+ /// 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; }
};
-
-//===--------------------------------------------------------------------===//
-// Implement some stuff prototyped above...
-//===--------------------------------------------------------------------===//
-
-inline BasicBlock::pred_iterator BasicBlock::pred_begin() {
- return pred_iterator(this);
-}
-inline BasicBlock::pred_const_iterator BasicBlock::pred_begin() const {
- return pred_const_iterator(this);
-}
-inline BasicBlock::pred_iterator BasicBlock::pred_end() {
- return pred_iterator(this,true);
-}
-inline BasicBlock::pred_const_iterator BasicBlock::pred_end() const {
- return pred_const_iterator(this,true);
+inline int
+ilist_traits<Instruction>::getListOffset() {
+ return BasicBlock::getInstListOffset();
}
-inline BasicBlock::succ_iterator BasicBlock::succ_begin() {
- return succ_iterator(getTerminator());
-}
-inline BasicBlock::succ_const_iterator BasicBlock::succ_begin() const {
- return succ_const_iterator(getTerminator());
-}
-inline BasicBlock::succ_iterator BasicBlock::succ_end() {
- return succ_iterator(getTerminator(),true);
-}
-inline BasicBlock::succ_const_iterator BasicBlock::succ_end() const {
- return succ_const_iterator(getTerminator(),true);
-}
+} // End llvm namespace
#endif
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