llvm-6502/include/llvm/CFG.h
Chris Lattner 7170838f84 New file
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@13 91177308-0d34-0410-b5e6-96231b3b80d8
2001-06-07 21:18:08 +00:00

283 lines
9.2 KiB
C++

//===-- llvm/CFG.h - CFG definitions and useful classes ----------*- C++ -*--=//
//
// This file contains the class definitions useful for operating on the control
// flow graph.
//
// Currently it contains functionality for these three applications:
//
// 1. Iterate over the predecessors of a basic block:
// pred_iterator, pred_const_iterator, pred_begin, pred_end
// 2. Iterate over the successors of a basic block:
// succ_iterator, succ_const_iterator, succ_begin, succ_end
//an iterator to iterate over the basic
// blocks of a method in depth first order.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CFG_H
#define LLVM_CFG_H
#include <set>
#include <stack>
#include "llvm/BasicBlock.h"
#include "llvm/InstrTypes.h"
//===----------------------------------------------------------------------===//
// Interface
//===----------------------------------------------------------------------===//
//===--------------------------------------------------------------------===//
// 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*, BasicBlock::use_iterator> pred_iterator;
typedef PredIterator<const BasicBlock*,
BasicBlock::use_const_iterator> pred_const_iterator;
inline pred_iterator pred_begin( BasicBlock *BB);
inline pred_const_iterator pred_begin(const BasicBlock *BB);
inline pred_iterator pred_end ( BasicBlock *BB);
inline pred_const_iterator pred_end (const BasicBlock *BB);
//===--------------------------------------------------------------------===//
// 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( BasicBlock *BB);
inline succ_const_iterator succ_begin(const BasicBlock *BB);
inline succ_iterator succ_end ( BasicBlock *BB);
inline succ_const_iterator succ_end (const BasicBlock *BB);
//===--------------------------------------------------------------------===//
// Depth First CFG iterator code
//===--------------------------------------------------------------------===//
//
// This is used to figure out what basic blocks we could be going to...
//
// Forward declare iterator class template...
template<class BBType, class SuccItTy> class DFIterator;
typedef DFIterator<BasicBlock, succ_iterator> df_iterator;
typedef DFIterator<const BasicBlock,
succ_const_iterator> df_const_iterator;
inline df_iterator df_begin( BasicBlock *BB);
inline df_const_iterator df_begin(const BasicBlock *BB);
inline df_iterator df_end ( BasicBlock *BB);
inline df_const_iterator df_end (const BasicBlock *BB);
//===----------------------------------------------------------------------===//
// Implementation
//===----------------------------------------------------------------------===//
//===----------------------------------------------------------------------===//
// Basic Block Predecessor Iterator
//
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;
}
};
inline pred_iterator pred_begin( BasicBlock *BB) {
return pred_iterator(BB);
}
inline pred_const_iterator pred_begin(const BasicBlock *BB) {
return pred_const_iterator(BB);
}
inline pred_iterator pred_end( BasicBlock *BB) {
return pred_iterator(BB,true);
}
inline pred_const_iterator pred_end(const BasicBlock *BB) {
return pred_const_iterator(BB,true);
}
//===----------------------------------------------------------------------===//
// Basic Block Successor Iterator
//
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;
}
};
inline succ_iterator succ_begin( BasicBlock *BB) {
return succ_iterator(BB->getTerminator());
}
inline succ_const_iterator succ_begin(const BasicBlock *BB) {
return succ_const_iterator(BB->getTerminator());
}
inline succ_iterator succ_end( BasicBlock *BB) {
return succ_iterator(BB->getTerminator(),true);
}
inline succ_const_iterator succ_end(const BasicBlock *BB) {
return succ_const_iterator(BB->getTerminator(),true);
}
//===----------------------------------------------------------------------===//
// Depth First Iterator
//
template<class BBType, class SuccItTy>
class DFIterator { // BasicBlock Depth First Iterator
set<BBType *> Visited; // All of the blocks visited so far...
// VisitStack - Used to maintain the ordering. Top = current block
// First element is basic block pointer, second is the 'next child' to visit
stack<pair<BBType *, SuccItTy> > VisitStack;
public:
typedef DFIterator<BBType, SuccItTy> _Self;
typedef forward_iterator_tag iterator_category;
typedef BBType *pointer;
inline DFIterator(BBType *BB) {
Visited.insert(BB);
VisitStack.push(make_pair(BB, succ_begin(BB)));
}
inline DFIterator(BBType *BB, bool) { /* End is when stack is empty */ }
inline bool operator==(const _Self& x) const {
return VisitStack == x.VisitStack;
}
inline bool operator!=(const _Self& x) const { return !operator==(x); }
inline pointer operator*() const {
return VisitStack.top().first;
}
// This is a nonstandard operator-> that dereferences the pointer an extra
// time... so that you can actually call methods ON the BasicBlock, because
// the contained type is a pointer. This allows BBIt->getTerminator() f.e.
//
inline BBType *operator->() const { return operator*(); }
inline _Self& operator++() { // Preincrement
do {
pair<BBType *, SuccItTy> &Top = VisitStack.top();
BBType *BB = Top.first;
SuccItTy &It = Top.second;
do {
BBType *Next = *It++;
if (!Visited.count(Next)) { // Has our next sibling been visited?
// No, do it now.
VisitStack.push(make_pair(Next, succ_begin(BB)));
return *this;
}
} while (It != succ_end(BB));
// Oops, ran out of successors... go up a level on the stack.
VisitStack.pop();
} while (!VisitStack.empty());
return *this;
}
inline _Self operator++(int) { // Postincrement
_Self tmp = *this; ++*this; return tmp;
}
};
inline df_iterator df_begin(BasicBlock *BB) {
return df_iterator(BB);
}
inline df_const_iterator df_begin(const BasicBlock *BB) {
return df_const_iterator(BB);
}
inline df_iterator df_end(BasicBlock *BB) {
return df_iterator(BB, true);
}
inline df_const_iterator df_end(const BasicBlock *BB) {
return df_const_iterator(BB, true);
}
#endif