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Implement support for postdominators, except in dom frontiers
llvm-svn: 142
This commit is contained in:
Chris Lattner
parent
a6c8b30e9d
commit
c385bebc89
@ -5,6 +5,7 @@
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//===----------------------------------------------------------------------===//
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#include "llvm/Analysis/Dominators.h"
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#include "llvm/Analysis/SimplifyCFG.h" // To get cfg::UnifyAllExitNodes
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#include "llvm/CFG.h"
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#include "llvm/Tools/STLExtras.h"
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#include <algorithm>
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@ -26,6 +27,14 @@ void set_intersect(set<Ty> &S1, const set<Ty2> &S2) {
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}
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}
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//===----------------------------------------------------------------------===//
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// DominatorBase Implementation
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//===----------------------------------------------------------------------===//
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bool cfg::DominatorBase::isPostDominator() const {
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return Root != Root->getParent()->front();
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}
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//===----------------------------------------------------------------------===//
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// DominatorSet Implementation
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@ -34,8 +43,14 @@ void set_intersect(set<Ty> &S1, const set<Ty2> &S2) {
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// DominatorSet ctor - Build either the dominator set or the post-dominator
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// set for a method...
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//
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cfg::DominatorSet::DominatorSet(const Method *M, bool PostDomSet)
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: Root(M->front()) {
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cfg::DominatorSet::DominatorSet(const Method *M) : DominatorBase(M->front()) {
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calcForwardDominatorSet(M);
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}
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// calcForwardDominatorSet - This method calculates the forward dominator sets
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// for the specified method.
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//
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void cfg::DominatorSet::calcForwardDominatorSet(const Method *M) {
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assert(Root && M && "Can't build dominator set of null method!");
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bool Changed;
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do {
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@ -70,7 +85,53 @@ cfg::DominatorSet::DominatorSet(const Method *M, bool PostDomSet)
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WorkingSet.clear(); // Clear out the set for next iteration
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}
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} while (Changed);
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}
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// Postdominator set constructor. This ctor converts the specified method to
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// only have a single exit node (return stmt), then calculates the post
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// dominance sets for the method.
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//
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cfg::DominatorSet::DominatorSet(Method *M, bool PostDomSet)
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: DominatorBase(M->front()) {
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if (!PostDomSet) { calcForwardDominatorSet(M); return; }
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Root = cfg::UnifyAllExitNodes(M);
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assert(Root && "TODO: Don't handle case where there are no exit nodes yet!");
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bool Changed;
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do {
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Changed = false;
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set<const BasicBlock*> Visited;
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DomSetType WorkingSet;
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idf_const_iterator It = idf_begin(Root), End = idf_end(Root);
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for ( ; It != End; ++It) {
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const BasicBlock *BB = *It;
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succ_const_iterator PI = succ_begin(BB), PEnd = succ_end(BB);
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if (PI != PEnd) { // Is there SOME predecessor?
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// Loop until we get to a successor that has had it's dom set filled
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// in at least once. We are guaranteed to have this because we are
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// traversing the graph in DFO and have handled start nodes specially.
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//
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while (Doms[*PI].size() == 0) ++PI;
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WorkingSet = Doms[*PI];
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for (++PI; PI != PEnd; ++PI) { // Intersect all of the successor sets
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DomSetType &PredSet = Doms[*PI];
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if (PredSet.size())
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set_intersect(WorkingSet, PredSet);
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}
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}
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WorkingSet.insert(BB); // A block always dominates itself
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DomSetType &BBSet = Doms[BB];
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if (BBSet != WorkingSet) {
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BBSet.swap(WorkingSet); // Constant time operation!
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Changed = true; // The sets changed.
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}
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WorkingSet.clear(); // Clear out the set for next iteration
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}
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} while (Changed);
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}
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@ -128,8 +189,7 @@ cfg::DominatorTree::~DominatorTree() {
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cfg::DominatorTree::DominatorTree(const ImmediateDominators &IDoms)
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: Root(IDoms.getRoot()) {
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assert(Root && Root->getParent() && "No method for IDoms?");
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: DominatorBase(IDoms.getRoot()) {
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const Method *M = Root->getParent();
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Nodes[Root] = new Node(Root, 0); // Add a node for the root...
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@ -153,47 +213,86 @@ cfg::DominatorTree::DominatorTree(const ImmediateDominators &IDoms)
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}
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void cfg::DominatorTree::calculate(const DominatorSet &DS) {
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Root = DS.getRoot();
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assert(Root && Root->getParent() && "No method for IDoms?");
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const Method *M = Root->getParent();
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Nodes[Root] = new Node(Root, 0); // Add a node for the root...
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// Iterate over all nodes in depth first order...
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for (df_const_iterator I = df_begin(M), E = df_end(M); I != E; ++I) {
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const BasicBlock *BB = *I;
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const DominatorSet::DomSetType &Dominators = DS.getDominators(BB);
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unsigned DomSetSize = Dominators.size();
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if (DomSetSize == 1) continue; // Root node... IDom = null
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// Loop over all dominators of this node. This corresponds to looping over
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// nodes in the dominator chain, looking for a node whose dominator set is
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// equal to the current nodes, except that the current node does not exist
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// in it. This means that it is one level higher in the dom chain than the
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// current node, and it is our idom! We know that we have already added
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// a DominatorTree node for our idom, because the idom must be a
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// predecessor in the depth first order that we are iterating through the
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// method.
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//
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DominatorSet::DomSetType::const_iterator I = Dominators.begin();
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DominatorSet::DomSetType::const_iterator End = Dominators.end();
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for (; I != End; ++I) { // Iterate over dominators...
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// All of our dominators should form a chain, where the number of elements
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// in the dominator set indicates what level the node is at in the chain.
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// We want the node immediately above us, so it will have an identical
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// dominator set, except that BB will not dominate it... therefore it's
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// dominator set size will be one less than BB's...
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if (!isPostDominator()) {
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// Iterate over all nodes in depth first order...
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for (df_const_iterator I = df_begin(Root), E = df_end(Root); I != E; ++I) {
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const BasicBlock *BB = *I;
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const DominatorSet::DomSetType &Dominators = DS.getDominators(BB);
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unsigned DomSetSize = Dominators.size();
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if (DomSetSize == 1) continue; // Root node... IDom = null
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// Loop over all dominators of this node. This corresponds to looping over
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// nodes in the dominator chain, looking for a node whose dominator set is
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// equal to the current nodes, except that the current node does not exist
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// in it. This means that it is one level higher in the dom chain than the
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// current node, and it is our idom! We know that we have already added
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// a DominatorTree node for our idom, because the idom must be a
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// predecessor in the depth first order that we are iterating through the
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// method.
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//
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if (DS.getDominators(*I).size() == DomSetSize - 1) {
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// We know that the immediate dominator should already have a node,
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// because we are traversing the CFG in depth first order!
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DominatorSet::DomSetType::const_iterator I = Dominators.begin();
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DominatorSet::DomSetType::const_iterator End = Dominators.end();
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for (; I != End; ++I) { // Iterate over dominators...
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// All of our dominators should form a chain, where the number of elements
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// in the dominator set indicates what level the node is at in the chain.
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// We want the node immediately above us, so it will have an identical
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// dominator set, except that BB will not dominate it... therefore it's
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// dominator set size will be one less than BB's...
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//
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Node *IDomNode = Nodes[*I];
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assert(Nodes[*I] && "No node for IDOM?");
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// Add a new tree node for this BasicBlock, and link it as a child of
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// IDomNode
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Nodes[BB] = IDomNode->addChild(new Node(BB, IDomNode));
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break;
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if (DS.getDominators(*I).size() == DomSetSize - 1) {
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// We know that the immediate dominator should already have a node,
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// because we are traversing the CFG in depth first order!
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//
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Node *IDomNode = Nodes[*I];
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assert(IDomNode && "No node for IDOM?");
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// Add a new tree node for this BasicBlock, and link it as a child of
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// IDomNode
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Nodes[BB] = IDomNode->addChild(new Node(BB, IDomNode));
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break;
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}
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}
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}
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} else {
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// Iterate over all nodes in depth first order...
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for (idf_const_iterator I = idf_begin(Root), E = idf_end(Root); I != E; ++I) {
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const BasicBlock *BB = *I;
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const DominatorSet::DomSetType &Dominators = DS.getDominators(BB);
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unsigned DomSetSize = Dominators.size();
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if (DomSetSize == 1) continue; // Root node... IDom = null
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// Loop over all dominators of this node. This corresponds to looping over
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// nodes in the dominator chain, looking for a node whose dominator set is
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// equal to the current nodes, except that the current node does not exist
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// in it. This means that it is one level higher in the dom chain than the
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// current node, and it is our idom! We know that we have already added
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// a DominatorTree node for our idom, because the idom must be a
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// predecessor in the depth first order that we are iterating through the
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// method.
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//
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DominatorSet::DomSetType::const_iterator I = Dominators.begin();
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DominatorSet::DomSetType::const_iterator End = Dominators.end();
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for (; I != End; ++I) { // Iterate over dominators...
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// All of our dominators should form a chain, where the number of elements
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// in the dominator set indicates what level the node is at in the chain.
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// We want the node immediately above us, so it will have an identical
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// dominator set, except that BB will not dominate it... therefore it's
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// dominator set size will be one less than BB's...
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//
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if (DS.getDominators(*I).size() == DomSetSize - 1) {
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// We know that the immediate dominator should already have a node,
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// because we are traversing the CFG in depth first order!
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//
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Node *IDomNode = Nodes[*I];
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assert(IDomNode && "No node for IDOM?");
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// Add a new tree node for this BasicBlock, and link it as a child of
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// IDomNode
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Nodes[BB] = IDomNode->addChild(new Node(BB, IDomNode));
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break;
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}
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}
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}
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}
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@ -237,3 +336,36 @@ cfg::DominanceFrontier::calcDomFrontier(const DominatorTree &DT,
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return S;
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}
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const cfg::DominanceFrontier::DomSetType &
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cfg::DominanceFrontier::calcPostDomFrontier(const DominatorTree &DT,
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const DominatorTree::Node *Node) {
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// Loop over CFG successors to calculate DFlocal[Node]
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const BasicBlock *BB = Node->getNode();
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DomSetType &S = Frontiers[BB]; // The new set to fill in...
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for (pred_const_iterator SI = pred_begin(BB), SE = pred_end(BB);
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SI != SE; ++SI) {
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// Does Node immediately dominate this predeccessor?
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if (DT[*SI]->getIDom() != Node)
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S.insert(*SI);
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}
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// At this point, S is DFlocal. Now we union in DFup's of our children...
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// Loop through and visit the nodes that Node immediately dominates (Node's
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// children in the IDomTree)
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//
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for (DominatorTree::Node::const_iterator NI = Node->begin(), NE = Node->end();
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NI != NE; ++NI) {
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DominatorTree::Node *IDominee = *NI;
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const DomSetType &ChildDF = calcDomFrontier(DT, IDominee);
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DomSetType::const_iterator CDFI = ChildDF.begin(), CDFE = ChildDF.end();
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for (; CDFI != CDFE; ++CDFI) {
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if (!Node->dominates(DT[*CDFI]))
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S.insert(*CDFI);
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}
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}
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return S;
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}
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@ -5,6 +5,7 @@
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//===----------------------------------------------------------------------===//
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#include "llvm/Analysis/Dominators.h"
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#include "llvm/Analysis/SimplifyCFG.h" // To get cfg::UnifyAllExitNodes
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#include "llvm/CFG.h"
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#include "llvm/Tools/STLExtras.h"
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#include <algorithm>
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@ -26,6 +27,14 @@ void set_intersect(set<Ty> &S1, const set<Ty2> &S2) {
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}
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}
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//===----------------------------------------------------------------------===//
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// DominatorBase Implementation
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//===----------------------------------------------------------------------===//
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bool cfg::DominatorBase::isPostDominator() const {
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return Root != Root->getParent()->front();
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}
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//===----------------------------------------------------------------------===//
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// DominatorSet Implementation
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@ -34,8 +43,14 @@ void set_intersect(set<Ty> &S1, const set<Ty2> &S2) {
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// DominatorSet ctor - Build either the dominator set or the post-dominator
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// set for a method...
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//
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cfg::DominatorSet::DominatorSet(const Method *M, bool PostDomSet)
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: Root(M->front()) {
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cfg::DominatorSet::DominatorSet(const Method *M) : DominatorBase(M->front()) {
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calcForwardDominatorSet(M);
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}
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// calcForwardDominatorSet - This method calculates the forward dominator sets
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// for the specified method.
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//
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void cfg::DominatorSet::calcForwardDominatorSet(const Method *M) {
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assert(Root && M && "Can't build dominator set of null method!");
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bool Changed;
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do {
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@ -70,7 +85,53 @@ cfg::DominatorSet::DominatorSet(const Method *M, bool PostDomSet)
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WorkingSet.clear(); // Clear out the set for next iteration
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}
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} while (Changed);
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}
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// Postdominator set constructor. This ctor converts the specified method to
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// only have a single exit node (return stmt), then calculates the post
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// dominance sets for the method.
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//
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cfg::DominatorSet::DominatorSet(Method *M, bool PostDomSet)
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: DominatorBase(M->front()) {
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if (!PostDomSet) { calcForwardDominatorSet(M); return; }
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Root = cfg::UnifyAllExitNodes(M);
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assert(Root && "TODO: Don't handle case where there are no exit nodes yet!");
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bool Changed;
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do {
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Changed = false;
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set<const BasicBlock*> Visited;
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DomSetType WorkingSet;
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idf_const_iterator It = idf_begin(Root), End = idf_end(Root);
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for ( ; It != End; ++It) {
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const BasicBlock *BB = *It;
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succ_const_iterator PI = succ_begin(BB), PEnd = succ_end(BB);
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if (PI != PEnd) { // Is there SOME predecessor?
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// Loop until we get to a successor that has had it's dom set filled
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// in at least once. We are guaranteed to have this because we are
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// traversing the graph in DFO and have handled start nodes specially.
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//
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while (Doms[*PI].size() == 0) ++PI;
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WorkingSet = Doms[*PI];
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for (++PI; PI != PEnd; ++PI) { // Intersect all of the successor sets
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DomSetType &PredSet = Doms[*PI];
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if (PredSet.size())
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set_intersect(WorkingSet, PredSet);
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}
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}
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WorkingSet.insert(BB); // A block always dominates itself
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DomSetType &BBSet = Doms[BB];
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if (BBSet != WorkingSet) {
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BBSet.swap(WorkingSet); // Constant time operation!
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Changed = true; // The sets changed.
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}
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WorkingSet.clear(); // Clear out the set for next iteration
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}
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} while (Changed);
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}
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@ -128,8 +189,7 @@ cfg::DominatorTree::~DominatorTree() {
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cfg::DominatorTree::DominatorTree(const ImmediateDominators &IDoms)
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: Root(IDoms.getRoot()) {
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assert(Root && Root->getParent() && "No method for IDoms?");
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: DominatorBase(IDoms.getRoot()) {
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const Method *M = Root->getParent();
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Nodes[Root] = new Node(Root, 0); // Add a node for the root...
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@ -153,47 +213,86 @@ cfg::DominatorTree::DominatorTree(const ImmediateDominators &IDoms)
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}
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void cfg::DominatorTree::calculate(const DominatorSet &DS) {
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Root = DS.getRoot();
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assert(Root && Root->getParent() && "No method for IDoms?");
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const Method *M = Root->getParent();
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Nodes[Root] = new Node(Root, 0); // Add a node for the root...
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// Iterate over all nodes in depth first order...
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for (df_const_iterator I = df_begin(M), E = df_end(M); I != E; ++I) {
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const BasicBlock *BB = *I;
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const DominatorSet::DomSetType &Dominators = DS.getDominators(BB);
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unsigned DomSetSize = Dominators.size();
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if (DomSetSize == 1) continue; // Root node... IDom = null
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// Loop over all dominators of this node. This corresponds to looping over
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// nodes in the dominator chain, looking for a node whose dominator set is
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// equal to the current nodes, except that the current node does not exist
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// in it. This means that it is one level higher in the dom chain than the
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// current node, and it is our idom! We know that we have already added
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// a DominatorTree node for our idom, because the idom must be a
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// predecessor in the depth first order that we are iterating through the
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// method.
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//
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DominatorSet::DomSetType::const_iterator I = Dominators.begin();
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DominatorSet::DomSetType::const_iterator End = Dominators.end();
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for (; I != End; ++I) { // Iterate over dominators...
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// All of our dominators should form a chain, where the number of elements
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// in the dominator set indicates what level the node is at in the chain.
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// We want the node immediately above us, so it will have an identical
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// dominator set, except that BB will not dominate it... therefore it's
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// dominator set size will be one less than BB's...
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if (!isPostDominator()) {
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// Iterate over all nodes in depth first order...
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for (df_const_iterator I = df_begin(Root), E = df_end(Root); I != E; ++I) {
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const BasicBlock *BB = *I;
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const DominatorSet::DomSetType &Dominators = DS.getDominators(BB);
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unsigned DomSetSize = Dominators.size();
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if (DomSetSize == 1) continue; // Root node... IDom = null
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// Loop over all dominators of this node. This corresponds to looping over
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// nodes in the dominator chain, looking for a node whose dominator set is
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// equal to the current nodes, except that the current node does not exist
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||||
// in it. This means that it is one level higher in the dom chain than the
|
||||
// current node, and it is our idom! We know that we have already added
|
||||
// a DominatorTree node for our idom, because the idom must be a
|
||||
// predecessor in the depth first order that we are iterating through the
|
||||
// method.
|
||||
//
|
||||
if (DS.getDominators(*I).size() == DomSetSize - 1) {
|
||||
// We know that the immediate dominator should already have a node,
|
||||
// because we are traversing the CFG in depth first order!
|
||||
DominatorSet::DomSetType::const_iterator I = Dominators.begin();
|
||||
DominatorSet::DomSetType::const_iterator End = Dominators.end();
|
||||
for (; I != End; ++I) { // Iterate over dominators...
|
||||
// All of our dominators should form a chain, where the number of elements
|
||||
// in the dominator set indicates what level the node is at in the chain.
|
||||
// We want the node immediately above us, so it will have an identical
|
||||
// dominator set, except that BB will not dominate it... therefore it's
|
||||
// dominator set size will be one less than BB's...
|
||||
//
|
||||
Node *IDomNode = Nodes[*I];
|
||||
assert(Nodes[*I] && "No node for IDOM?");
|
||||
|
||||
// Add a new tree node for this BasicBlock, and link it as a child of
|
||||
// IDomNode
|
||||
Nodes[BB] = IDomNode->addChild(new Node(BB, IDomNode));
|
||||
break;
|
||||
if (DS.getDominators(*I).size() == DomSetSize - 1) {
|
||||
// We know that the immediate dominator should already have a node,
|
||||
// because we are traversing the CFG in depth first order!
|
||||
//
|
||||
Node *IDomNode = Nodes[*I];
|
||||
assert(IDomNode && "No node for IDOM?");
|
||||
|
||||
// Add a new tree node for this BasicBlock, and link it as a child of
|
||||
// IDomNode
|
||||
Nodes[BB] = IDomNode->addChild(new Node(BB, IDomNode));
|
||||
break;
|
||||
}
|
||||
}
|
||||
}
|
||||
} else {
|
||||
// Iterate over all nodes in depth first order...
|
||||
for (idf_const_iterator I = idf_begin(Root), E = idf_end(Root); I != E; ++I) {
|
||||
const BasicBlock *BB = *I;
|
||||
const DominatorSet::DomSetType &Dominators = DS.getDominators(BB);
|
||||
unsigned DomSetSize = Dominators.size();
|
||||
if (DomSetSize == 1) continue; // Root node... IDom = null
|
||||
|
||||
// Loop over all dominators of this node. This corresponds to looping over
|
||||
// nodes in the dominator chain, looking for a node whose dominator set is
|
||||
// equal to the current nodes, except that the current node does not exist
|
||||
// in it. This means that it is one level higher in the dom chain than the
|
||||
// current node, and it is our idom! We know that we have already added
|
||||
// a DominatorTree node for our idom, because the idom must be a
|
||||
// predecessor in the depth first order that we are iterating through the
|
||||
// method.
|
||||
//
|
||||
DominatorSet::DomSetType::const_iterator I = Dominators.begin();
|
||||
DominatorSet::DomSetType::const_iterator End = Dominators.end();
|
||||
for (; I != End; ++I) { // Iterate over dominators...
|
||||
// All of our dominators should form a chain, where the number of elements
|
||||
// in the dominator set indicates what level the node is at in the chain.
|
||||
// We want the node immediately above us, so it will have an identical
|
||||
// dominator set, except that BB will not dominate it... therefore it's
|
||||
// dominator set size will be one less than BB's...
|
||||
//
|
||||
if (DS.getDominators(*I).size() == DomSetSize - 1) {
|
||||
// We know that the immediate dominator should already have a node,
|
||||
// because we are traversing the CFG in depth first order!
|
||||
//
|
||||
Node *IDomNode = Nodes[*I];
|
||||
assert(IDomNode && "No node for IDOM?");
|
||||
|
||||
// Add a new tree node for this BasicBlock, and link it as a child of
|
||||
// IDomNode
|
||||
Nodes[BB] = IDomNode->addChild(new Node(BB, IDomNode));
|
||||
break;
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
@ -237,3 +336,36 @@ cfg::DominanceFrontier::calcDomFrontier(const DominatorTree &DT,
|
||||
|
||||
return S;
|
||||
}
|
||||
|
||||
const cfg::DominanceFrontier::DomSetType &
|
||||
cfg::DominanceFrontier::calcPostDomFrontier(const DominatorTree &DT,
|
||||
const DominatorTree::Node *Node) {
|
||||
// Loop over CFG successors to calculate DFlocal[Node]
|
||||
const BasicBlock *BB = Node->getNode();
|
||||
DomSetType &S = Frontiers[BB]; // The new set to fill in...
|
||||
|
||||
for (pred_const_iterator SI = pred_begin(BB), SE = pred_end(BB);
|
||||
SI != SE; ++SI) {
|
||||
// Does Node immediately dominate this predeccessor?
|
||||
if (DT[*SI]->getIDom() != Node)
|
||||
S.insert(*SI);
|
||||
}
|
||||
|
||||
// At this point, S is DFlocal. Now we union in DFup's of our children...
|
||||
// Loop through and visit the nodes that Node immediately dominates (Node's
|
||||
// children in the IDomTree)
|
||||
//
|
||||
for (DominatorTree::Node::const_iterator NI = Node->begin(), NE = Node->end();
|
||||
NI != NE; ++NI) {
|
||||
DominatorTree::Node *IDominee = *NI;
|
||||
const DomSetType &ChildDF = calcDomFrontier(DT, IDominee);
|
||||
|
||||
DomSetType::const_iterator CDFI = ChildDF.begin(), CDFE = ChildDF.end();
|
||||
for (; CDFI != CDFE; ++CDFI) {
|
||||
if (!Node->dominates(DT[*CDFI]))
|
||||
S.insert(*CDFI);
|
||||
}
|
||||
}
|
||||
|
||||
return S;
|
||||
}
|
||||
|
||||
Loading…
Reference in New Issue
Block a user