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* Added comments

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* Made iterators inherit from appropriate iterator base class
* Abstracted out graphs from depth first iterator
* Add "Inverse" traversal of CFG

llvm-svn: 139
This commit is contained in:
Chris Lattner 2001-07-06 16:56:17 +00:00
parent 8024bde7c7
commit 719d5b2899
2 changed files with 133 additions and 65 deletions
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166
llvm/include/llvm/CFG.h
View file

@ -12,24 +12,22 @@
// 3. Iterate over the basic blocks of a method in depth first ordering or
// reverse depth first order. df_iterator, df_const_iterator,
// df_begin, df_end. df_begin takes an arg to specify reverse or not.
// 4. Iterator over the basic blocks of a method in post order.
// 5. Iterator over a method in reverse post order.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CFG_H
#define LLVM_CFG_H
#include "llvm/CFGdecls.h" // See this file for concise interface info
#include <set>
#include <stack>
#include <iterator>
#include "llvm/Method.h"
#include "llvm/BasicBlock.h"
#include "llvm/InstrTypes.h"
//===----------------------------------------------------------------------===//
// Interface
//===----------------------------------------------------------------------===//
#include "llvm/CFGdecls.h" // See this file for concise interface info
namespace cfg {
//===----------------------------------------------------------------------===//
@ -41,19 +39,14 @@ namespace cfg {
//
template <class _Ptr, class _USE_iterator> // Predecessor Iterator
class PredIterator {
const _Ptr BB;
class PredIterator : public std::bidirectional_iterator<_Ptr, ptrdiff_t> {
_Ptr *BB;
_USE_iterator It;
public:
typedef PredIterator<_Ptr,_USE_iterator> _Self;
typedef bidirectional_iterator_tag iterator_category;
typedef _Ptr &reference;
typedef unsigned difference_type;
typedef _Ptr value_type;
typedef _Ptr pointer;
inline void advancePastConstPool() {
// TODO: This is bad
// Loop to ignore constant pool references
while (It != BB->use_end() &&
((!(*It)->isInstruction()) ||
@ -61,10 +54,10 @@ public:
++It;
}
inline PredIterator(_Ptr bb) : BB(bb), It(bb->use_begin()) {
inline PredIterator(_Ptr *bb) : BB(bb), It(bb->use_begin()) {
advancePastConstPool();
}
inline PredIterator(_Ptr bb, bool) : BB(bb), It(bb->use_end()) {}
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); }
@ -108,17 +101,12 @@ inline pred_const_iterator pred_end(const BasicBlock *BB) {
//
template <class _Term, class _BB> // Successor Iterator
class SuccIterator {
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
typedef bidirectional_iterator_tag iterator_category;
typedef _BB &reference;
typedef unsigned difference_type;
typedef _BB value_type;
typedef _BB pointer;
inline SuccIterator(_Term T) : Term(T), idx(0) {} // begin iterator
inline SuccIterator(_Term T, bool)
@ -128,7 +116,7 @@ public:
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 pointer operator->() const { return operator*(); }
inline _Self& operator++() { ++idx; return *this; } // Preincrement
inline _Self operator++(int) { // Postincrement
@ -155,44 +143,99 @@ inline succ_const_iterator succ_end(const BasicBlock *BB) {
}
//===----------------------------------------------------------------------===//
// Graph Type Declarations
//
// BasicBlockGraph - Represent a standard traversal of a CFG
// ConstBasicBlockGraph - Represent a standard traversal of a const CFG
// InverseBasicBlockGraph - Represent a inverse traversal of a CFG
// ConstInverseBasicBlockGraph - Represent a inverse traversal of a const CFG
//
// An Inverse traversal of a graph is where we chase predecessors, instead of
// successors.
//
struct BasicBlockGraph {
typedef BasicBlock NodeType;
typedef succ_iterator ChildIteratorType;
static inline ChildIteratorType child_begin(NodeType *N) {
return succ_begin(N);
}
static inline ChildIteratorType child_end(NodeType *N) {
return succ_end(N);
}
};
struct ConstBasicBlockGraph {
typedef const BasicBlock NodeType;
typedef succ_const_iterator ChildIteratorType;
static inline ChildIteratorType child_begin(NodeType *N) {
return succ_begin(N);
}
static inline ChildIteratorType child_end(NodeType *N) {
return succ_end(N);
}
};
struct InverseBasicBlockGraph {
typedef BasicBlock NodeType;
typedef pred_iterator ChildIteratorType;
static inline ChildIteratorType child_begin(NodeType *N) {
return pred_begin(N);
}
static inline ChildIteratorType child_end(NodeType *N) {
return pred_end(N);
}
};
struct ConstInverseBasicBlockGraph {
typedef const BasicBlock NodeType;
typedef pred_const_iterator ChildIteratorType;
static inline ChildIteratorType child_begin(NodeType *N) {
return pred_begin(N);
}
static inline ChildIteratorType child_end(NodeType *N) {
return pred_end(N);
}
};
//===----------------------------------------------------------------------===//
// Depth First Iterator
//
template<class BBType, class SuccItTy>
class DFIterator { // BasicBlock Depth First Iterator
set<BBType *> Visited; // All of the blocks visited so far...
// BasicBlock Depth First Iterator
template<class GI>
class DFIterator : public std::forward_iterator<typename GI::NodeType,
ptrdiff_t> {
typedef typename GI::NodeType NodeType;
typedef typename GI::ChildIteratorType ChildItTy;
set<NodeType *> 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;
stack<pair<NodeType *, ChildItTy> > VisitStack;
const bool Reverse; // Iterate over children before self?
private:
void reverseEnterNode() {
pair<BBType *, SuccItTy> &Top = VisitStack.top();
BBType *BB = Top.first;
SuccItTy &It = Top.second;
for (; It != succ_end(BB); ++It) {
BBType *Child = *It;
pair<NodeType *, ChildItTy> &Top = VisitStack.top();
NodeType *BB = Top.first;
ChildItTy &It = Top.second;
for (; It != GI::child_end(BB); ++It) {
NodeType *Child = *It;
if (!Visited.count(Child)) {
Visited.insert(Child);
VisitStack.push(make_pair(Child, succ_begin(Child)));
VisitStack.push(make_pair(Child, GI::child_begin(Child)));
reverseEnterNode();
return;
}
}
}
public:
typedef DFIterator<BBType, SuccItTy> _Self;
typedef DFIterator<GI> _Self;
typedef forward_iterator_tag iterator_category;
typedef BBType *pointer;
typedef BBType &reference;
typedef void difference_type;
typedef BBType *value_type;
inline DFIterator(BBType *BB, bool reverse) : Reverse(reverse) {
inline DFIterator(NodeType *BB, bool reverse) : Reverse(reverse) {
Visited.insert(BB);
VisitStack.push(make_pair(BB, succ_begin(BB)));
VisitStack.push(make_pair(BB, GI::child_begin(BB)));
if (Reverse) reverseEnterNode();
}
inline DFIterator() { /* End is when stack is empty */ }
@ -210,26 +253,26 @@ public:
// 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 NodeType *operator->() const { return operator*(); }
inline _Self& operator++() { // Preincrement
if (Reverse) { // Reverse Depth First Iterator
if (VisitStack.top().second == succ_end(VisitStack.top().first))
if (VisitStack.top().second == GI::child_end(VisitStack.top().first))
VisitStack.pop();
if (!VisitStack.empty())
reverseEnterNode();
} else { // Normal Depth First Iterator
do {
pair<BBType *, SuccItTy> &Top = VisitStack.top();
BBType *BB = Top.first;
SuccItTy &It = Top.second;
pair<NodeType *, ChildItTy> &Top = VisitStack.top();
NodeType *BB = Top.first;
ChildItTy &It = Top.second;
while (It != succ_end(BB)) {
BBType *Next = *It++;
while (It != GI::child_end(BB)) {
NodeType *Next = *It++;
if (!Visited.count(Next)) { // Has our next sibling been visited?
// No, do it now.
Visited.insert(Next);
VisitStack.push(make_pair(Next, succ_begin(Next)));
VisitStack.push(make_pair(Next, GI::child_begin(Next)));
return *this;
}
}
@ -275,12 +318,27 @@ inline df_const_iterator df_end(const BasicBlock*) {
}
inline idf_iterator idf_begin(BasicBlock *BB, bool Reverse = false) {
return idf_iterator(BB, Reverse);
}
inline idf_const_iterator idf_begin(const BasicBlock *BB, bool Reverse = false) {
return idf_const_iterator(BB, Reverse);
}
inline idf_iterator idf_end(BasicBlock*) {
return idf_iterator();
}
inline idf_const_iterator idf_end(const BasicBlock*) {
return idf_const_iterator();
}
//===----------------------------------------------------------------------===//
// Post Order CFG iterator code
//
template<class BBType, class SuccItTy>
class POIterator {
class POIterator : public std::forward_iterator<BBType, ptrdiff_t> {
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
@ -298,12 +356,6 @@ class POIterator {
public:
typedef POIterator<BBType, SuccItTy> _Self;
typedef forward_iterator_tag iterator_category;
typedef BBType *pointer;
typedef BBType &reference;
typedef void difference_type;
typedef BBType *value_type;
inline POIterator(BBType *BB) {
Visited.insert(BB);
VisitStack.push(make_pair(BB, succ_begin(BB)));

32
llvm/include/llvm/CFGdecls.h
View file

@ -31,8 +31,8 @@ namespace cfg {
// Forward declare iterator class template...
template <class _Ptr, class _USE_iterator> class PredIterator;
typedef PredIterator<BasicBlock*, Value::use_iterator> pred_iterator;
typedef PredIterator<const BasicBlock*,
typedef PredIterator<BasicBlock, Value::use_iterator> pred_iterator;
typedef PredIterator<const BasicBlock,
Value::use_const_iterator> pred_const_iterator;
inline pred_iterator pred_begin( BasicBlock *BB);
@ -51,9 +51,9 @@ inline pred_const_iterator pred_end (const BasicBlock *BB);
// Forward declare iterator class template...
template <class _Term, class _BB> class SuccIterator;
typedef SuccIterator<TerminatorInst*, BasicBlock*> succ_iterator;
typedef SuccIterator<TerminatorInst*, BasicBlock> succ_iterator;
typedef SuccIterator<const TerminatorInst*,
const BasicBlock*> succ_const_iterator;
const BasicBlock> succ_const_iterator;
inline succ_iterator succ_begin( BasicBlock *BB);
inline succ_const_iterator succ_begin(const BasicBlock *BB);
@ -69,13 +69,17 @@ inline succ_const_iterator succ_end (const BasicBlock *BB);
// reverse depth first ordering, depending on the value passed to the df_begin
// method.
//
struct BasicBlockGraph;
struct ConstBasicBlockGraph;
struct InverseBasicBlockGraph;
struct ConstInverseBasicBlockGraph;
// Forward declare iterator class template...
template<class BBType, class SuccItTy> class DFIterator;
template<class GraphInfo> class DFIterator;
typedef DFIterator<BasicBlock, succ_iterator> df_iterator;
typedef DFIterator<const BasicBlock,
succ_const_iterator> df_const_iterator;
// Normal Depth First Iterator Definitions (Forward and Reverse)
typedef DFIterator< BasicBlockGraph> df_iterator;
typedef DFIterator<ConstBasicBlockGraph> df_const_iterator;
inline df_iterator df_begin( Method *M, bool Reverse = false);
inline df_const_iterator df_begin(const Method *M, bool Reverse = false);
@ -88,6 +92,18 @@ inline df_iterator df_end ( BasicBlock *BB);
inline df_const_iterator df_end (const BasicBlock *BB);
// Inverse Depth First Iterator Definitions (Forward and Reverse) - Traverse
// predecessors instead of successors...
//
typedef DFIterator< InverseBasicBlockGraph> idf_iterator;
typedef DFIterator<ConstInverseBasicBlockGraph> idf_const_iterator;
inline idf_iterator idf_begin( BasicBlock *BB, bool Reverse = false);
inline idf_const_iterator idf_begin(const BasicBlock *BB, bool Reverse = false);
inline idf_iterator idf_end ( BasicBlock *BB);
inline idf_const_iterator idf_end (const BasicBlock *BB);
//===--------------------------------------------------------------------===//
// Post Order CFG iterator code
//===--------------------------------------------------------------------===//