llvm-mirror/include/llvm/BasicBlock.h
Chris Lattner 345daca305 Pull predecessor and successor iterators out of the CFG*.h files, and plop them into
the BasicBlock class where they should be.  pred_begin/pred_end become methods on BasicBlock,
and the cfg namespace isn't used anymore.

llvm-svn: 691
2001-10-01 13:19:53 +00:00

319 lines
12 KiB
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.
//
// 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. :)
//
//===----------------------------------------------------------------------===//
//
// 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.
//
//===----------------------------------------------------------------------===//
#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 <iterator>
class Instruction;
class Method;
class TerminatorInst;
class MachineCodeForBasicBlock;
class BasicBlock : public Value { // Basic blocks are data objects also
template <class _Ptr, class _USE_iterator> class PredIterator;
template <class _Term, class _BB> class SuccIterator;
public:
typedef ValueHolder<Instruction, BasicBlock, Method> InstListType;
private :
InstListType InstList;
MachineCodeForBasicBlock* machineInstrVec;
friend class ValueHolder<BasicBlock,Method,Method>;
void setParent(Method *parent);
public:
// Instruction iterators...
typedef InstListType::iterator iterator;
typedef InstListType::const_iterator const_iterator;
typedef reverse_iterator<const_iterator> const_reverse_iterator;
typedef reverse_iterator<iterator> reverse_iterator;
// Predecessor and successor iterators...
typedef PredIterator<BasicBlock, Value::use_iterator> pred_iterator;
typedef PredIterator<const BasicBlock,
Value::use_const_iterator> pred_const_iterator;
typedef SuccIterator<TerminatorInst*, BasicBlock> succ_iterator;
typedef SuccIterator<const TerminatorInst*,
const BasicBlock> succ_const_iterator;
// Ctor, dtor
BasicBlock(const string &Name = "", Method *Parent = 0);
~BasicBlock();
// Specialize setName to take care of symbol table majik
virtual void setName(const string &name, SymbolTable *ST = 0);
// getParent - Return the enclosing method, or null if none
const Method *getParent() const { return InstList.getParent(); }
Method *getParent() { return InstList.getParent(); }
// 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;
// Machine code accessor...
inline MachineCodeForBasicBlock& getMachineInstrVec() const {
return *machineInstrVec;
}
//===--------------------------------------------------------------------===//
// 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 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; }
// 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);
// 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 <class _Ptr, class _USE_iterator> // 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() &&
((!(*It)->isInstruction()) ||
!(((Instruction*)(*It))->isTerminator())))
++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 (*It)->castInstructionAsserting()->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 <class _Term, class _BB> // 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<BasicBlock*> {
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<const BasicBlock*> {
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();
}
};
// 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<Inverse<BasicBlock*> > {
typedef BasicBlock NodeType;
typedef BasicBlock::pred_iterator ChildIteratorType;
static NodeType *getEntryNode(Inverse<BasicBlock *> 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();
}
};
template <> struct GraphTraits<Inverse<const BasicBlock*> > {
typedef const BasicBlock NodeType;
typedef BasicBlock::pred_const_iterator ChildIteratorType;
static NodeType *getEntryNode(Inverse<const BasicBlock*> 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();
}
};
#endif