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IntervalPartition & IntervalIterator classes have been split out into

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their own .h files

llvm-svn: 61
This commit is contained in:
Chris Lattner 2001-06-24 04:05:09 +00:00
parent 4c16155c36
commit 658a50fe1b
1 changed files with 24 additions and 316 deletions
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340
llvm/include/llvm/Analysis/Interval.h
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@ -1,36 +1,24 @@
//===- llvm/Analysis/Intervals.h - Interval partition Calculation-*- C++ -*--=// //===- llvm/Analysis/Interval.h - Interval Class Declaration -----*- C++ -*--=//
// //
// This file contains the declaration of the cfg::IntervalPartition class, which // This file contains the declaration of the cfg::Interval class, which
// calculates and represents the interval partition of a method, or a // represents a set of CFG nodes and is a portion of an interval partition.
// preexisting interval partition. //
// // Intervals have some interesting and useful properties, including the
// In this way, the interval partition may be used to reduce a flow graph down // following:
// to its degenerate single node interval partition (unless it is irreducible). // 1. The header node of an interval dominates all of the elements of the
// // interval
// TODO: The IntervalPartition class should take a bool parameter that tells
// whether it should add the "tails" of an interval to an interval itself or if
// they should be represented as distinct intervals.
// //
//===----------------------------------------------------------------------===// //===----------------------------------------------------------------------===//
#ifndef LLVM_INTERVALS_H #ifndef LLVM_INTERVAL_H
#define LLVM_INTERVALS_H #define LLVM_INTERVAL_H
#include "llvm/Method.h"
#include "llvm/CFG.h"
#include <vector> #include <vector>
#include <map>
#include <stack>
#include <set>
#include <algorithm>
class Method;
class BasicBlock; class BasicBlock;
namespace cfg { namespace cfg {
class IntervalPartition;
//===----------------------------------------------------------------------===// //===----------------------------------------------------------------------===//
// //
// Interval Class - An Interval is a set of nodes defined such that every node // Interval Class - An Interval is a set of nodes defined such that every node
@ -38,8 +26,6 @@ class IntervalPartition;
// header) // header)
// //
class Interval { class Interval {
friend class IntervalPartition;
// HeaderNode - The header BasicBlock, which dominates all BasicBlocks in this // HeaderNode - The header BasicBlock, which dominates all BasicBlocks in this
// interval. Also, any loops in this interval must go through the HeaderNode. // interval. Also, any loops in this interval must go through the HeaderNode.
// //
@ -49,6 +35,10 @@ public:
typedef vector<BasicBlock*>::iterator pred_iterator; typedef vector<BasicBlock*>::iterator pred_iterator;
typedef vector<BasicBlock*>::iterator node_iterator; typedef vector<BasicBlock*>::iterator node_iterator;
inline Interval(BasicBlock *Header) : HeaderNode(Header) {
Nodes.push_back(Header);
}
inline BasicBlock *getHeaderNode() const { return HeaderNode; } inline BasicBlock *getHeaderNode() const { return HeaderNode; }
// Nodes - The basic blocks in this interval. // Nodes - The basic blocks in this interval.
@ -68,21 +58,24 @@ public:
// contains - Find out if a basic block is in this interval // contains - Find out if a basic block is in this interval
inline bool contains(BasicBlock *BB) const { inline bool contains(BasicBlock *BB) const {
return find(Nodes.begin(), Nodes.end(), BB) != Nodes.end(); for (unsigned i = 0; i < Nodes.size(); ++i)
if (Nodes[i] == BB) return true;
return false;
// I don't want the dependency on <algorithm>
//return find(Nodes.begin(), Nodes.end(), BB) != Nodes.end();
} }
// isSuccessor - find out if a basic block is a successor of this Interval // isSuccessor - find out if a basic block is a successor of this Interval
inline bool isSuccessor(BasicBlock *BB) const { inline bool isSuccessor(BasicBlock *BB) const {
return find(Successors.begin(), Successors.end(), BB) != Successors.end(); for (unsigned i = 0; i < Successors.size(); ++i)
if (Successors[i] == BB) return true;
return false;
// I don't want the dependency on <algorithm>
//return find(Successors.begin(), Successors.end(), BB) != Successors.end();
} }
// isLoop - Find out if there is a back edge in this interval... // isLoop - Find out if there is a back edge in this interval...
bool isLoop() const; bool isLoop() const;
//private: // Only accessable by IntervalPartition class
inline Interval(BasicBlock *Header) : HeaderNode(Header) {
Nodes.push_back(Header);
}
}; };
@ -106,291 +99,6 @@ inline Interval::pred_iterator pred_end(Interval *I) {
return I->Predecessors.end(); return I->Predecessors.end();
} }
//===----------------------------------------------------------------------===//
// IntervalIterator
//
// TODO: Provide an interval iterator that codifies the internals of
// IntervalPartition. Inside, it would have a stack of Interval*'s, and would
// walk the interval partition in depth first order. IntervalPartition would
// then be a client of this iterator. The iterator should work on Method*,
// const Method*, IntervalPartition*, and const IntervalPartition*.
//
template<class NodeTy, class OrigContainer_t>
class IntervalIterator {
stack<pair<Interval, typename Interval::succ_iterator> > IntStack;
set<BasicBlock*> Visited;
OrigContainer_t *OrigContainer;
public:
typedef BasicBlock* _BB;
typedef IntervalIterator<NodeTy, OrigContainer_t> _Self;
typedef forward_iterator_tag iterator_category;
IntervalIterator() {} // End iterator, empty stack
IntervalIterator(Method *M) {
OrigContainer = M;
if (!ProcessInterval(M->getBasicBlocks().front())) {
assert(0 && "ProcessInterval should never fail for first interval!");
}
}
inline bool operator==(const _Self& x) const { return IntStack == x.IntStack; }
inline bool operator!=(const _Self& x) const { return !operator==(x); }
inline Interval &operator*() const { return IntStack.top(); }
inline Interval *operator->() const { return &(operator*()); }
inline _Self& operator++() { // Preincrement
do {
// All of the intervals on the stack have been visited. Try visiting their
// successors now.
Interval &CurInt = IntStack.top().first;
Interval::iterator &SuccIt = IntStack.top().second,End = succ_end(&CurInt);
for (; SuccIt != End; ++SuccIt) // Loop over all interval successors
if (ProcessInterval(*SuccIt)) // Found a new interval!
return *this; // Use it!
// We ran out of successors for this interval... pop off the stack
IntStack.pop();
} while (!IntStack.empty());
return *this;
}
inline _Self operator++(int) { // Postincrement
_Self tmp = *this; ++*this; return tmp;
}
private:
// ProcessInterval - This method is used during the construction of the
// interval graph. It walks through the source graph, recursively creating
// an interval per invokation until the entire graph is covered. This uses
// the ProcessNode method to add all of the nodes to the interval.
//
// This method is templated because it may operate on two different source
// graphs: a basic block graph, or a preexisting interval graph.
//
bool ProcessInterval(NodeTy *Node) {
BasicBlock *Header = getNodeHeader(Node);
if (Visited.count(Header)) return false;
Interval Int(Header);
Visited.insert(Header); // The header has now been visited!
// Check all of our successors to see if they are in the interval...
for (typename NodeTy::succ_iterator I = succ_begin(Node), E = succ_end(Node);
I != E; ++I)
ProcessNode(&Int, getSourceGraphNode(OrigContainer, *I));
IntStack.push(make_pair(Int, succ_begin(&Int)));
return true;
}
// ProcessNode - This method is called by ProcessInterval to add nodes to the
// interval being constructed, and it is also called recursively as it walks
// the source graph. A node is added to the current interval only if all of
// its predecessors are already in the graph. This also takes care of keeping
// the successor set of an interval up to date.
//
// This method is templated because it may operate on two different source
// graphs: a basic block graph, or a preexisting interval graph.
//
void ProcessNode(Interval *Int, NodeTy *Node) {
assert(Int && "Null interval == bad!");
assert(Node && "Null Node == bad!");
BasicBlock *NodeHeader = getNodeHeader(Node);
if (Visited.count(NodeHeader)) { // Node already been visited?
if (Int->contains(NodeHeader)) { // Already in this interval...
return;
} else { // In another interval, add as successor
if (!Int->isSuccessor(NodeHeader)) // Add only if not already in set
Int->Successors.push_back(NodeHeader);
}
} else { // Otherwise, not in interval yet
for (typename NodeTy::pred_iterator I = pred_begin(Node),
E = pred_end(Node); I != E; ++I) {
if (!Int->contains(*I)) { // If pred not in interval, we can't be
if (!Int->isSuccessor(NodeHeader)) // Add only if not already in set
Int->Successors.push_back(NodeHeader);
return; // See you later
}
}
// If we get here, then all of the predecessors of BB are in the interval
// already. In this case, we must add BB to the interval!
addNodeToInterval(Int, Node);
Visited.insert(NodeHeader); // The node has now been visited!
if (Int->isSuccessor(NodeHeader)) {
// If we were in the successor list from before... remove from succ list
Int->Successors.erase(remove(Int->Successors.begin(),
Int->Successors.end(), NodeHeader),
Int->Successors.end());
}
// Now that we have discovered that Node is in the interval, perhaps some
// of its successors are as well?
for (typename NodeTy::succ_iterator It = succ_begin(Node),
End = succ_end(Node); It != End; ++It)
ProcessNode(Int, getSourceGraphNode(OrigContainer, *It));
}
}
};
//===----------------------------------------------------------------------===//
//
// IntervalPartition - This class builds and holds an "interval partition" for
// a method. This partition divides the control flow graph into a set of
// maximal intervals, as defined with the properties above. Intuitively, a
// BasicBlock is a (possibly nonexistent) loop with a "tail" of non looping
// nodes following it.
//
class IntervalPartition {
typedef map<BasicBlock*, Interval*> IntervalMapTy;
IntervalMapTy IntervalMap;
typedef vector<Interval*> IntervalListTy;
IntervalListTy IntervalList;
Interval *RootInterval;
public:
typedef IntervalListTy::iterator iterator;
public:
// IntervalPartition ctor - Build the partition for the specified method
IntervalPartition(Method *M);
// IntervalPartition ctor - Build a reduced interval partition from an
// existing interval graph. This takes an additional boolean parameter to
// distinguish it from a copy constructor. Always pass in false for now.
//
IntervalPartition(IntervalPartition &I, bool);
// Destructor - Free memory
~IntervalPartition();
// getRootInterval() - Return the root interval that contains the starting
// block of the method.
inline Interval *getRootInterval() { return RootInterval; }
// isDegeneratePartition() - Returns true if the interval partition contains
// a single interval, and thus cannot be simplified anymore.
bool isDegeneratePartition() { return size() == 1; }
// TODO: isIrreducible - look for triangle graph.
// getBlockInterval - Return the interval that a basic block exists in.
inline Interval *getBlockInterval(BasicBlock *BB) {
IntervalMapTy::iterator I = IntervalMap.find(BB);
return I != IntervalMap.end() ? I->second : 0;
}
// Iterators to iterate over all of the intervals in the method
inline iterator begin() { return IntervalList.begin(); }
inline iterator end() { return IntervalList.end(); }
inline unsigned size() { return IntervalList.size(); }
private:
// ProcessInterval - This method is used during the construction of the
// interval graph. It walks through the source graph, recursively creating
// an interval per invokation until the entire graph is covered. This uses
// the ProcessNode method to add all of the nodes to the interval.
//
// This method is templated because it may operate on two different source
// graphs: a basic block graph, or a preexisting interval graph.
//
template<class NodeTy, class OrigContainer>
void ProcessInterval(NodeTy *Node, OrigContainer *OC);
// ProcessNode - This method is called by ProcessInterval to add nodes to the
// interval being constructed, and it is also called recursively as it walks
// the source graph. A node is added to the current interval only if all of
// its predecessors are already in the graph. This also takes care of keeping
// the successor set of an interval up to date.
//
// This method is templated because it may operate on two different source
// graphs: a basic block graph, or a preexisting interval graph.
//
template<class NodeTy, class OrigContainer>
void ProcessNode(Interval *Int, NodeTy *Node, OrigContainer *OC);
// addNodeToInterval - This method exists to assist the generic ProcessNode
// with the task of adding a node to the new interval, depending on the
// type of the source node. In the case of a CFG source graph (BasicBlock
// case), the BasicBlock itself is added to the interval. In the case of
// an IntervalPartition source graph (Interval case), all of the member
// BasicBlocks are added to the interval.
//
inline void addNodeToInterval(Interval *Int, Interval *I);
inline void addNodeToInterval(Interval *Int, BasicBlock *BB);
// updatePredecessors - Interval generation only sets the successor fields of
// the interval data structures. After interval generation is complete,
// run through all of the intervals and propogate successor info as
// predecessor info.
//
void updatePredecessors(Interval *Int);
};
// getNodeHeader - Given a source graph node and the source graph, return the
// BasicBlock that is the header node. This is the opposite of
// getSourceGraphNode.
//
inline BasicBlock *getNodeHeader(BasicBlock *BB) { return BB; }
inline BasicBlock *getNodeHeader(Interval *I) { return I->getHeaderNode(); }
// getSourceGraphNode - Given a BasicBlock and the source graph, return the
// source graph node that corresponds to the BasicBlock. This is the opposite
// of getNodeHeader.
//
inline BasicBlock *getSourceGraphNode(Method *, BasicBlock *BB) {
return BB;
}
inline Interval *getSourceGraphNode(IntervalPartition *IP, BasicBlock *BB) {
return IP->getBlockInterval(BB);
}
// addNodeToInterval - This method exists to assist the generic ProcessNode
// with the task of adding a node to the new interval, depending on the
// type of the source node. In the case of a CFG source graph (BasicBlock
// case), the BasicBlock itself is added to the interval.
//
inline void addNodeToInterval(Interval *Int, BasicBlock *BB){
Int->Nodes.push_back(BB);
}
// addNodeToInterval - This method exists to assist the generic ProcessNode
// with the task of adding a node to the new interval, depending on the
// type of the source node. In the case of a CFG source graph (BasicBlock
// case), the BasicBlock itself is added to the interval. In the case of
// an IntervalPartition source graph (Interval case), all of the member
// BasicBlocks are added to the interval.
//
inline void addNodeToInterval(Interval *Int, Interval *I) {
// Add all of the nodes in I as new nodes in Int.
copy(I->Nodes.begin(), I->Nodes.end(), back_inserter(Int->Nodes));
}
typedef IntervalIterator<BasicBlock, Method> method_interval_iterator;
method_interval_iterator intervals_begin(Method *M) {
return method_interval_iterator(M);
}
method_interval_iterator intervals_end(Method *M) {
return method_interval_iterator();
}
} // End namespace cfg } // End namespace cfg
#endif #endif