//
// The LLVM Compiler Infrastructure
//
-// This file was developed by Owen Anderson and is distributed under
-// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#define LLVM_ANALYSIS_DOMINATOR_INTERNALS_H
#include "llvm/Analysis/Dominators.h"
-#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallPtrSet.h"
+
//===----------------------------------------------------------------------===//
//
// DominatorTree construction - This pass constructs immediate dominator
// documentation purposes.
#if 0
InfoRec &VInfo = DT.Info[DT.Roots[i]];
- VInfo.Semi = ++N;
+ VInfo.DFSNum = VInfo.Semi = ++N;
VInfo.Label = V;
Vertex.push_back(V); // Vertex[n] = V;
}
}
#else
+ bool IsChilOfArtificialExit = (N != 0);
+
std::vector<std::pair<typename GraphT::NodeType*,
typename GraphT::ChildIteratorType> > Worklist;
Worklist.push_back(std::make_pair(V, GraphT::child_begin(V)));
typename GraphT::NodeType* BB = Worklist.back().first;
typename GraphT::ChildIteratorType NextSucc = Worklist.back().second;
+ typename DominatorTreeBase<typename GraphT::NodeType>::InfoRec &BBInfo =
+ DT.Info[BB];
+
// First time we visited this BB?
if (NextSucc == GraphT::child_begin(BB)) {
- typename DominatorTreeBase<typename GraphT::NodeType>::InfoRec &BBInfo =
- DT.Info[BB];
- BBInfo.Semi = ++N;
+ BBInfo.DFSNum = BBInfo.Semi = ++N;
BBInfo.Label = BB;
DT.Vertex.push_back(BB); // Vertex[n] = V;
//BBInfo[V].Ancestor = 0; // Ancestor[n] = 0
//BBInfo[V].Child = 0; // Child[v] = 0
BBInfo.Size = 1; // Size[v] = 1
+
+ if (IsChilOfArtificialExit)
+ BBInfo.Parent = 1;
+
+ IsChilOfArtificialExit = false;
}
-
+
+ // store the DFS number of the current BB - the reference to BBInfo might
+ // get invalidated when processing the successors.
+ unsigned BBDFSNum = BBInfo.DFSNum;
+
// If we are done with this block, remove it from the worklist.
if (NextSucc == GraphT::child_end(BB)) {
Worklist.pop_back();
typename DominatorTreeBase<typename GraphT::NodeType>::InfoRec &SuccVInfo =
DT.Info[Succ];
if (SuccVInfo.Semi == 0) {
- SuccVInfo.Parent = BB;
+ SuccVInfo.Parent = BBDFSNum;
Worklist.push_back(std::make_pair(Succ, GraphT::child_begin(Succ)));
}
}
template<class GraphT>
void Compress(DominatorTreeBase<typename GraphT::NodeType>& DT,
typename GraphT::NodeType *VIn) {
- std::vector<typename GraphT::NodeType*> Work;
+ SmallVector<typename GraphT::NodeType*, 32> Work;
SmallPtrSet<typename GraphT::NodeType*, 32> Visited;
- typename GraphT::NodeType* VInAncestor = DT.Info[VIn].Ancestor;
typename DominatorTreeBase<typename GraphT::NodeType>::InfoRec &VInVAInfo =
- DT.Info[VInAncestor];
+ DT.Info[DT.Vertex[DT.Info[VIn].Ancestor]];
if (VInVAInfo.Ancestor != 0)
Work.push_back(VIn);
typename GraphT::NodeType* V = Work.back();
typename DominatorTreeBase<typename GraphT::NodeType>::InfoRec &VInfo =
DT.Info[V];
- typename GraphT::NodeType* VAncestor = VInfo.Ancestor;
+ typename GraphT::NodeType* VAncestor = DT.Vertex[VInfo.Ancestor];
typename DominatorTreeBase<typename GraphT::NodeType>::InfoRec &VAInfo =
DT.Info[VAncestor];
}
template<class GraphT>
-typename GraphT::NodeType* Eval(DominatorTreeBase<typename GraphT::NodeType>& DT,
- typename GraphT::NodeType *V) {
+typename GraphT::NodeType*
+Eval(DominatorTreeBase<typename GraphT::NodeType>& DT,
+ typename GraphT::NodeType *V) {
typename DominatorTreeBase<typename GraphT::NodeType>::InfoRec &VInfo =
DT.Info[V];
#if !BALANCE_IDOM_TREE
template<class GraphT>
void Link(DominatorTreeBase<typename GraphT::NodeType>& DT,
- typename GraphT::NodeType* V, typename GraphT::NodeType* W,
+ unsigned DFSNumV, typename GraphT::NodeType* W,
typename DominatorTreeBase<typename GraphT::NodeType>::InfoRec &WInfo) {
#if !BALANCE_IDOM_TREE
// Higher-complexity but faster implementation
- WInfo.Ancestor = V;
+ WInfo.Ancestor = DFSNumV;
#else
// Lower-complexity but slower implementation
GraphT::NodeType* WLabel = WInfo.Label;
void Calculate(DominatorTreeBase<typename GraphTraits<NodeT>::NodeType>& DT,
FuncT& F) {
typedef GraphTraits<NodeT> GraphT;
-
+
+ unsigned N = 0;
+ bool MultipleRoots = (DT.Roots.size() > 1);
+ if (MultipleRoots) {
+ typename DominatorTreeBase<typename GraphT::NodeType>::InfoRec &BBInfo =
+ DT.Info[NULL];
+ BBInfo.DFSNum = BBInfo.Semi = ++N;
+ BBInfo.Label = NULL;
+
+ DT.Vertex.push_back(NULL); // Vertex[n] = V;
+ //BBInfo[V].Ancestor = 0; // Ancestor[n] = 0
+ //BBInfo[V].Child = 0; // Child[v] = 0
+ BBInfo.Size = 1; // Size[v] = 1
+ }
+
// Step #1: Number blocks in depth-first order and initialize variables used
// in later stages of the algorithm.
- unsigned N = 0;
- for (unsigned i = 0, e = DT.Roots.size(); i != e; ++i)
+ for (unsigned i = 0, e = static_cast<unsigned>(DT.Roots.size());
+ i != e; ++i)
N = DFSPass<GraphT>(DT, DT.Roots[i], N);
+ // it might be that some blocks did not get a DFS number (e.g., blocks of
+ // infinite loops). In these cases an artificial exit node is required.
+ MultipleRoots |= (DT.isPostDominator() && N != F.size());
+
for (unsigned i = N; i >= 2; --i) {
typename GraphT::NodeType* W = DT.Vertex[i];
typename DominatorTreeBase<typename GraphT::NodeType>::InfoRec &WInfo =
DT.Info[W];
// Step #2: Calculate the semidominators of all vertices
- for (typename GraphTraits<Inverse<NodeT> >::ChildIteratorType CI =
- GraphTraits<Inverse<NodeT> >::child_begin(W),
- E = GraphTraits<Inverse<NodeT> >::child_end(W); CI != E; ++CI)
- if (DT.Info.count(*CI)) { // Only if this predecessor is reachable!
- unsigned SemiU = DT.Info[Eval<GraphT>(DT, *CI)].Semi;
+
+ // initialize the semi dominator to point to the parent node
+ WInfo.Semi = WInfo.Parent;
+ typedef GraphTraits<Inverse<NodeT> > InvTraits;
+ for (typename InvTraits::ChildIteratorType CI =
+ InvTraits::child_begin(W),
+ E = InvTraits::child_end(W); CI != E; ++CI) {
+ typename InvTraits::NodeType *N = *CI;
+ if (DT.Info.count(N)) { // Only if this predecessor is reachable!
+ unsigned SemiU = DT.Info[Eval<GraphT>(DT, N)].Semi;
if (SemiU < WInfo.Semi)
WInfo.Semi = SemiU;
}
+ }
DT.Info[DT.Vertex[WInfo.Semi]].Bucket.push_back(W);
- typename GraphT::NodeType* WParent = WInfo.Parent;
- Link<GraphT>(DT, WParent, W, WInfo);
+ typename GraphT::NodeType* WParent = DT.Vertex[WInfo.Parent];
+ Link<GraphT>(DT, WInfo.Parent, W, WInfo);
// Step #3: Implicitly define the immediate dominator of vertices
std::vector<typename GraphT::NodeType*> &WParentBucket =
if (WIDom != DT.Vertex[DT.Info[W].Semi])
WIDom = DT.IDoms[WIDom];
}
-
+
if (DT.Roots.empty()) return;
-
+
// Add a node for the root. This node might be the actual root, if there is
// one exit block, or it may be the virtual exit (denoted by (BasicBlock *)0)
- // which postdominates all real exits if there are multiple exit blocks.
- typename GraphT::NodeType* Root = DT.Roots.size() == 1 ? DT.Roots[0]
- : 0;
- DT.DomTreeNodes[Root] = DT.RootNode = new DomTreeNode(Root, 0);
-
+ // which postdominates all real exits if there are multiple exit blocks, or
+ // an infinite loop.
+ typename GraphT::NodeType* Root = !MultipleRoots ? DT.Roots[0] : 0;
+
+ DT.DomTreeNodes[Root] = DT.RootNode =
+ new DomTreeNodeBase<typename GraphT::NodeType>(Root, 0);
+
// Loop over all of the reachable blocks in the function...
- for (Function::iterator I = F.begin(), E = F.end(); I != E; ++I)
- if (typename GraphT::NodeType* ImmDom = DT.getIDom(I)) {
- // Reachable block.
- DomTreeNode *BBNode = DT.DomTreeNodes[I];
- if (BBNode) continue; // Haven't calculated this node yet?
-
- // Get or calculate the node for the immediate dominator
- DomTreeNode *IDomNode = DT.getNodeForBlock(ImmDom);
-
- // Add a new tree node for this BasicBlock, and link it as a child of
- // IDomNode
- DomTreeNode *C = new DomTreeNode(I, IDomNode);
- DT.DomTreeNodes[I] = IDomNode->addChild(C);
- }
-
+ for (unsigned i = 2; i <= N; ++i) {
+ typename GraphT::NodeType* W = DT.Vertex[i];
+
+ DomTreeNodeBase<typename GraphT::NodeType> *BBNode = DT.DomTreeNodes[W];
+ if (BBNode) continue; // Haven't calculated this node yet?
+
+ typename GraphT::NodeType* ImmDom = DT.getIDom(W);
+
+ assert(ImmDom || DT.DomTreeNodes[NULL]);
+
+ // Get or calculate the node for the immediate dominator
+ DomTreeNodeBase<typename GraphT::NodeType> *IDomNode =
+ DT.getNodeForBlock(ImmDom);
+
+ // Add a new tree node for this BasicBlock, and link it as a child of
+ // IDomNode
+ DomTreeNodeBase<typename GraphT::NodeType> *C =
+ new DomTreeNodeBase<typename GraphT::NodeType>(W, IDomNode);
+ DT.DomTreeNodes[W] = IDomNode->addChild(C);
+ }
+
// Free temporary memory used to construct idom's
DT.IDoms.clear();
DT.Info.clear();
std::vector<typename GraphT::NodeType*>().swap(DT.Vertex);
-
- // FIXME: This does not work on PostDomTrees. It seems likely that this is
- // due to an error in the algorithm for post-dominators. This really should
- // be investigated and fixed at some point.
- // DT.updateDFSNumbers();
-
- // Start out with the DFS numbers being invalid. Let them be computed if
- // demanded.
- DT.DFSInfoValid = false;
+
+ DT.updateDFSNumbers();
}
}
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