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3831c553e3
Fix http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20070416/048092.html git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@36294 91177308-0d34-0410-b5e6-96231b3b80d8
999 lines
28 KiB
C++
999 lines
28 KiB
C++
//===- Dominators.cpp - Dominator Calculation -----------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file was developed by the LLVM research group and is distributed under
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// the University of Illinois Open Source License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements simple dominator construction algorithms for finding
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// forward dominators. Postdominators are available in libanalysis, but are not
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// included in libvmcore, because it's not needed. Forward dominators are
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// needed to support the Verifier pass.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Analysis/Dominators.h"
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#include "llvm/Support/CFG.h"
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#include "llvm/Assembly/Writer.h"
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#include "llvm/ADT/DepthFirstIterator.h"
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#include "llvm/ADT/SetOperations.h"
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#include "llvm/ADT/SmallPtrSet.h"
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#include "llvm/Instructions.h"
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#include <algorithm>
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using namespace llvm;
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namespace llvm {
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static std::ostream &operator<<(std::ostream &o,
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const std::set<BasicBlock*> &BBs) {
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for (std::set<BasicBlock*>::const_iterator I = BBs.begin(), E = BBs.end();
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I != E; ++I)
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if (*I)
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WriteAsOperand(o, *I, false);
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else
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o << " <<exit node>>";
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return o;
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}
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}
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//===----------------------------------------------------------------------===//
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// DominatorTree Implementation
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//===----------------------------------------------------------------------===//
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//
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// DominatorTree construction - This pass constructs immediate dominator
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// information for a flow-graph based on the algorithm described in this
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// document:
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//
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// A Fast Algorithm for Finding Dominators in a Flowgraph
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// T. Lengauer & R. Tarjan, ACM TOPLAS July 1979, pgs 121-141.
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//
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// This implements both the O(n*ack(n)) and the O(n*log(n)) versions of EVAL and
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// LINK, but it turns out that the theoretically slower O(n*log(n))
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// implementation is actually faster than the "efficient" algorithm (even for
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// large CFGs) because the constant overheads are substantially smaller. The
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// lower-complexity version can be enabled with the following #define:
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//
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#define BALANCE_IDOM_TREE 0
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//
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//===----------------------------------------------------------------------===//
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static RegisterPass<DominatorTree>
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E("domtree", "Dominator Tree Construction", true);
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unsigned DominatorTree::DFSPass(BasicBlock *V, InfoRec &VInfo,
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unsigned N) {
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// This is more understandable as a recursive algorithm, but we can't use the
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// recursive algorithm due to stack depth issues. Keep it here for
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// documentation purposes.
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#if 0
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VInfo.Semi = ++N;
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VInfo.Label = V;
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Vertex.push_back(V); // Vertex[n] = V;
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//Info[V].Ancestor = 0; // Ancestor[n] = 0
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//Info[V].Child = 0; // Child[v] = 0
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VInfo.Size = 1; // Size[v] = 1
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for (succ_iterator SI = succ_begin(V), E = succ_end(V); SI != E; ++SI) {
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InfoRec &SuccVInfo = Info[*SI];
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if (SuccVInfo.Semi == 0) {
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SuccVInfo.Parent = V;
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N = DFSPass(*SI, SuccVInfo, N);
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}
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}
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#else
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std::vector<std::pair<BasicBlock*, unsigned> > Worklist;
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Worklist.push_back(std::make_pair(V, 0U));
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while (!Worklist.empty()) {
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BasicBlock *BB = Worklist.back().first;
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unsigned NextSucc = Worklist.back().second;
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// First time we visited this BB?
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if (NextSucc == 0) {
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InfoRec &BBInfo = Info[BB];
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BBInfo.Semi = ++N;
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BBInfo.Label = BB;
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Vertex.push_back(BB); // Vertex[n] = V;
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//BBInfo[V].Ancestor = 0; // Ancestor[n] = 0
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//BBInfo[V].Child = 0; // Child[v] = 0
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BBInfo.Size = 1; // Size[v] = 1
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}
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// If we are done with this block, remove it from the worklist.
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if (NextSucc == BB->getTerminator()->getNumSuccessors()) {
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Worklist.pop_back();
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continue;
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}
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// Otherwise, increment the successor number for the next time we get to it.
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++Worklist.back().second;
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// Visit the successor next, if it isn't already visited.
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BasicBlock *Succ = BB->getTerminator()->getSuccessor(NextSucc);
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InfoRec &SuccVInfo = Info[Succ];
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if (SuccVInfo.Semi == 0) {
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SuccVInfo.Parent = BB;
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Worklist.push_back(std::make_pair(Succ, 0U));
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}
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}
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#endif
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return N;
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}
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void DominatorTree::Compress(BasicBlock *V, InfoRec &VInfo) {
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BasicBlock *VAncestor = VInfo.Ancestor;
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InfoRec &VAInfo = Info[VAncestor];
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if (VAInfo.Ancestor == 0)
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return;
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Compress(VAncestor, VAInfo);
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BasicBlock *VAncestorLabel = VAInfo.Label;
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BasicBlock *VLabel = VInfo.Label;
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if (Info[VAncestorLabel].Semi < Info[VLabel].Semi)
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VInfo.Label = VAncestorLabel;
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VInfo.Ancestor = VAInfo.Ancestor;
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}
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BasicBlock *DominatorTree::Eval(BasicBlock *V) {
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InfoRec &VInfo = Info[V];
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#if !BALANCE_IDOM_TREE
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// Higher-complexity but faster implementation
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if (VInfo.Ancestor == 0)
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return V;
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Compress(V, VInfo);
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return VInfo.Label;
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#else
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// Lower-complexity but slower implementation
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if (VInfo.Ancestor == 0)
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return VInfo.Label;
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Compress(V, VInfo);
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BasicBlock *VLabel = VInfo.Label;
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BasicBlock *VAncestorLabel = Info[VInfo.Ancestor].Label;
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if (Info[VAncestorLabel].Semi >= Info[VLabel].Semi)
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return VLabel;
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else
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return VAncestorLabel;
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#endif
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}
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void DominatorTree::Link(BasicBlock *V, BasicBlock *W, InfoRec &WInfo){
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#if !BALANCE_IDOM_TREE
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// Higher-complexity but faster implementation
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WInfo.Ancestor = V;
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#else
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// Lower-complexity but slower implementation
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BasicBlock *WLabel = WInfo.Label;
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unsigned WLabelSemi = Info[WLabel].Semi;
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BasicBlock *S = W;
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InfoRec *SInfo = &Info[S];
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BasicBlock *SChild = SInfo->Child;
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InfoRec *SChildInfo = &Info[SChild];
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while (WLabelSemi < Info[SChildInfo->Label].Semi) {
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BasicBlock *SChildChild = SChildInfo->Child;
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if (SInfo->Size+Info[SChildChild].Size >= 2*SChildInfo->Size) {
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SChildInfo->Ancestor = S;
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SInfo->Child = SChild = SChildChild;
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SChildInfo = &Info[SChild];
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} else {
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SChildInfo->Size = SInfo->Size;
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S = SInfo->Ancestor = SChild;
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SInfo = SChildInfo;
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SChild = SChildChild;
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SChildInfo = &Info[SChild];
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}
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}
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InfoRec &VInfo = Info[V];
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SInfo->Label = WLabel;
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assert(V != W && "The optimization here will not work in this case!");
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unsigned WSize = WInfo.Size;
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unsigned VSize = (VInfo.Size += WSize);
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if (VSize < 2*WSize)
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std::swap(S, VInfo.Child);
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while (S) {
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SInfo = &Info[S];
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SInfo->Ancestor = V;
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S = SInfo->Child;
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}
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#endif
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}
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void DominatorTree::calculate(Function& F) {
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BasicBlock* Root = Roots[0];
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Nodes[Root] = RootNode = new Node(Root, 0); // Add a node for the root...
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Vertex.push_back(0);
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// Step #1: Number blocks in depth-first order and initialize variables used
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// in later stages of the algorithm.
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unsigned N = 0;
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for (unsigned i = 0, e = Roots.size(); i != e; ++i)
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N = DFSPass(Roots[i], Info[Roots[i]], 0);
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for (unsigned i = N; i >= 2; --i) {
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BasicBlock *W = Vertex[i];
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InfoRec &WInfo = Info[W];
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// Step #2: Calculate the semidominators of all vertices
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for (pred_iterator PI = pred_begin(W), E = pred_end(W); PI != E; ++PI)
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if (Info.count(*PI)) { // Only if this predecessor is reachable!
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unsigned SemiU = Info[Eval(*PI)].Semi;
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if (SemiU < WInfo.Semi)
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WInfo.Semi = SemiU;
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}
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Info[Vertex[WInfo.Semi]].Bucket.push_back(W);
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BasicBlock *WParent = WInfo.Parent;
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Link(WParent, W, WInfo);
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// Step #3: Implicitly define the immediate dominator of vertices
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std::vector<BasicBlock*> &WParentBucket = Info[WParent].Bucket;
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while (!WParentBucket.empty()) {
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BasicBlock *V = WParentBucket.back();
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WParentBucket.pop_back();
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BasicBlock *U = Eval(V);
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IDoms[V] = Info[U].Semi < Info[V].Semi ? U : WParent;
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}
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}
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// Step #4: Explicitly define the immediate dominator of each vertex
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for (unsigned i = 2; i <= N; ++i) {
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BasicBlock *W = Vertex[i];
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BasicBlock *&WIDom = IDoms[W];
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if (WIDom != Vertex[Info[W].Semi])
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WIDom = IDoms[WIDom];
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}
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// Loop over all of the reachable blocks in the function...
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for (Function::iterator I = F.begin(), E = F.end(); I != E; ++I)
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if (BasicBlock *ImmDom = getIDom(I)) { // Reachable block.
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Node *&BBNode = Nodes[I];
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if (!BBNode) { // Haven't calculated this node yet?
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// Get or calculate the node for the immediate dominator
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Node *IDomNode = getNodeForBlock(ImmDom);
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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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BBNode = IDomNode->addChild(new Node(I, IDomNode));
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}
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}
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// Free temporary memory used to construct idom's
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Info.clear();
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IDoms.clear();
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std::vector<BasicBlock*>().swap(Vertex);
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}
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// DominatorTreeBase::reset - Free all of the tree node memory.
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//
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void DominatorTreeBase::reset() {
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for (NodeMapType::iterator I = Nodes.begin(), E = Nodes.end(); I != E; ++I)
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delete I->second;
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Nodes.clear();
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IDoms.clear();
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Roots.clear();
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Vertex.clear();
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RootNode = 0;
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}
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void DominatorTreeBase::Node::setIDom(Node *NewIDom) {
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assert(IDom && "No immediate dominator?");
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if (IDom != NewIDom) {
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std::vector<Node*>::iterator I =
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std::find(IDom->Children.begin(), IDom->Children.end(), this);
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assert(I != IDom->Children.end() &&
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"Not in immediate dominator children set!");
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// I am no longer your child...
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IDom->Children.erase(I);
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// Switch to new dominator
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IDom = NewIDom;
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IDom->Children.push_back(this);
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}
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}
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DominatorTreeBase::Node *DominatorTree::getNodeForBlock(BasicBlock *BB) {
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Node *&BBNode = Nodes[BB];
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if (BBNode) return BBNode;
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// Haven't calculated this node yet? Get or calculate the node for the
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// immediate dominator.
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BasicBlock *IDom = getIDom(BB);
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Node *IDomNode = getNodeForBlock(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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return BBNode = IDomNode->addChild(new Node(BB, IDomNode));
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}
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static std::ostream &operator<<(std::ostream &o,
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const DominatorTreeBase::Node *Node) {
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if (Node->getBlock())
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WriteAsOperand(o, Node->getBlock(), false);
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else
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o << " <<exit node>>";
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return o << "\n";
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}
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static void PrintDomTree(const DominatorTreeBase::Node *N, std::ostream &o,
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unsigned Lev) {
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o << std::string(2*Lev, ' ') << "[" << Lev << "] " << N;
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for (DominatorTreeBase::Node::const_iterator I = N->begin(), E = N->end();
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I != E; ++I)
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PrintDomTree(*I, o, Lev+1);
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}
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void DominatorTreeBase::print(std::ostream &o, const Module* ) const {
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o << "=============================--------------------------------\n"
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<< "Inorder Dominator Tree:\n";
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PrintDomTree(getRootNode(), o, 1);
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}
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bool DominatorTree::runOnFunction(Function &F) {
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reset(); // Reset from the last time we were run...
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Roots.push_back(&F.getEntryBlock());
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calculate(F);
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return false;
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}
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//===----------------------------------------------------------------------===//
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// DominanceFrontier Implementation
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//===----------------------------------------------------------------------===//
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static RegisterPass<DominanceFrontier>
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G("domfrontier", "Dominance Frontier Construction", true);
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namespace {
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class DFCalculateWorkObject {
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public:
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DFCalculateWorkObject(BasicBlock *B, BasicBlock *P,
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const DominatorTree::Node *N,
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const DominatorTree::Node *PN)
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: currentBB(B), parentBB(P), Node(N), parentNode(PN) {}
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BasicBlock *currentBB;
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BasicBlock *parentBB;
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const DominatorTree::Node *Node;
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const DominatorTree::Node *parentNode;
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};
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}
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const DominanceFrontier::DomSetType &
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DominanceFrontier::calculate(const DominatorTree &DT,
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const DominatorTree::Node *Node) {
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BasicBlock *BB = Node->getBlock();
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DomSetType *Result = NULL;
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std::vector<DFCalculateWorkObject> workList;
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SmallPtrSet<BasicBlock *, 32> visited;
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workList.push_back(DFCalculateWorkObject(BB, NULL, Node, NULL));
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do {
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DFCalculateWorkObject *currentW = &workList.back();
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assert (currentW && "Missing work object.");
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BasicBlock *currentBB = currentW->currentBB;
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BasicBlock *parentBB = currentW->parentBB;
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const DominatorTree::Node *currentNode = currentW->Node;
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const DominatorTree::Node *parentNode = currentW->parentNode;
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assert (currentBB && "Invalid work object. Missing current Basic Block");
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assert (currentNode && "Invalid work object. Missing current Node");
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DomSetType &S = Frontiers[currentBB];
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// Visit each block only once.
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if (visited.count(currentBB) == 0) {
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visited.insert(currentBB);
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// Loop over CFG successors to calculate DFlocal[currentNode]
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for (succ_iterator SI = succ_begin(currentBB), SE = succ_end(currentBB);
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SI != SE; ++SI) {
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// Does Node immediately dominate this successor?
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if (DT[*SI]->getIDom() != currentNode)
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S.insert(*SI);
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}
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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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bool visitChild = false;
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for (DominatorTree::Node::const_iterator NI = currentNode->begin(),
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NE = currentNode->end(); NI != NE; ++NI) {
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DominatorTree::Node *IDominee = *NI;
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BasicBlock *childBB = IDominee->getBlock();
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if (visited.count(childBB) == 0) {
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workList.push_back(DFCalculateWorkObject(childBB, currentBB,
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IDominee, currentNode));
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visitChild = true;
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}
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}
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// If all children are visited or there is any child then pop this block
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// from the workList.
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if (!visitChild) {
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if (!parentBB) {
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Result = &S;
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break;
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}
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DomSetType::const_iterator CDFI = S.begin(), CDFE = S.end();
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DomSetType &parentSet = Frontiers[parentBB];
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for (; CDFI != CDFE; ++CDFI) {
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if (!parentNode->properlyDominates(DT[*CDFI]))
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parentSet.insert(*CDFI);
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}
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workList.pop_back();
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}
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} while (!workList.empty());
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return *Result;
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}
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void DominanceFrontierBase::print(std::ostream &o, const Module* ) const {
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for (const_iterator I = begin(), E = end(); I != E; ++I) {
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o << " DomFrontier for BB";
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if (I->first)
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WriteAsOperand(o, I->first, false);
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else
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o << " <<exit node>>";
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o << " is:\t" << I->second << "\n";
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}
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}
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//===----------------------------------------------------------------------===//
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// ETOccurrence Implementation
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//===----------------------------------------------------------------------===//
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void ETOccurrence::Splay() {
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ETOccurrence *father;
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ETOccurrence *grandfather;
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int occdepth;
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int fatherdepth;
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while (Parent) {
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occdepth = Depth;
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father = Parent;
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fatherdepth = Parent->Depth;
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grandfather = father->Parent;
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// If we have no grandparent, a single zig or zag will do.
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if (!grandfather) {
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setDepthAdd(fatherdepth);
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MinOccurrence = father->MinOccurrence;
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Min = father->Min;
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// See what we have to rotate
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if (father->Left == this) {
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// Zig
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father->setLeft(Right);
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setRight(father);
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if (father->Left)
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father->Left->setDepthAdd(occdepth);
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} else {
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// Zag
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father->setRight(Left);
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setLeft(father);
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if (father->Right)
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father->Right->setDepthAdd(occdepth);
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}
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father->setDepth(-occdepth);
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Parent = NULL;
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father->recomputeMin();
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return;
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}
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|
|
// If we have a grandfather, we need to do some
|
|
// combination of zig and zag.
|
|
int grandfatherdepth = grandfather->Depth;
|
|
|
|
setDepthAdd(fatherdepth + grandfatherdepth);
|
|
MinOccurrence = grandfather->MinOccurrence;
|
|
Min = grandfather->Min;
|
|
|
|
ETOccurrence *greatgrandfather = grandfather->Parent;
|
|
|
|
if (grandfather->Left == father) {
|
|
if (father->Left == this) {
|
|
// Zig zig
|
|
grandfather->setLeft(father->Right);
|
|
father->setLeft(Right);
|
|
setRight(father);
|
|
father->setRight(grandfather);
|
|
|
|
father->setDepth(-occdepth);
|
|
|
|
if (father->Left)
|
|
father->Left->setDepthAdd(occdepth);
|
|
|
|
grandfather->setDepth(-fatherdepth);
|
|
if (grandfather->Left)
|
|
grandfather->Left->setDepthAdd(fatherdepth);
|
|
} else {
|
|
// Zag zig
|
|
grandfather->setLeft(Right);
|
|
father->setRight(Left);
|
|
setLeft(father);
|
|
setRight(grandfather);
|
|
|
|
father->setDepth(-occdepth);
|
|
if (father->Right)
|
|
father->Right->setDepthAdd(occdepth);
|
|
grandfather->setDepth(-occdepth - fatherdepth);
|
|
if (grandfather->Left)
|
|
grandfather->Left->setDepthAdd(occdepth + fatherdepth);
|
|
}
|
|
} else {
|
|
if (father->Left == this) {
|
|
// Zig zag
|
|
grandfather->setRight(Left);
|
|
father->setLeft(Right);
|
|
setLeft(grandfather);
|
|
setRight(father);
|
|
|
|
father->setDepth(-occdepth);
|
|
if (father->Left)
|
|
father->Left->setDepthAdd(occdepth);
|
|
grandfather->setDepth(-occdepth - fatherdepth);
|
|
if (grandfather->Right)
|
|
grandfather->Right->setDepthAdd(occdepth + fatherdepth);
|
|
} else { // Zag Zag
|
|
grandfather->setRight(father->Left);
|
|
father->setRight(Left);
|
|
setLeft(father);
|
|
father->setLeft(grandfather);
|
|
|
|
father->setDepth(-occdepth);
|
|
if (father->Right)
|
|
father->Right->setDepthAdd(occdepth);
|
|
grandfather->setDepth(-fatherdepth);
|
|
if (grandfather->Right)
|
|
grandfather->Right->setDepthAdd(fatherdepth);
|
|
}
|
|
}
|
|
|
|
// Might need one more rotate depending on greatgrandfather.
|
|
setParent(greatgrandfather);
|
|
if (greatgrandfather) {
|
|
if (greatgrandfather->Left == grandfather)
|
|
greatgrandfather->Left = this;
|
|
else
|
|
greatgrandfather->Right = this;
|
|
|
|
}
|
|
grandfather->recomputeMin();
|
|
father->recomputeMin();
|
|
}
|
|
}
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// ETNode implementation
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
void ETNode::Split() {
|
|
ETOccurrence *right, *left;
|
|
ETOccurrence *rightmost = RightmostOcc;
|
|
ETOccurrence *parent;
|
|
|
|
// Update the occurrence tree first.
|
|
RightmostOcc->Splay();
|
|
|
|
// Find the leftmost occurrence in the rightmost subtree, then splay
|
|
// around it.
|
|
for (right = rightmost->Right; right->Left; right = right->Left);
|
|
|
|
right->Splay();
|
|
|
|
// Start splitting
|
|
right->Left->Parent = NULL;
|
|
parent = ParentOcc;
|
|
parent->Splay();
|
|
ParentOcc = NULL;
|
|
|
|
left = parent->Left;
|
|
parent->Right->Parent = NULL;
|
|
|
|
right->setLeft(left);
|
|
|
|
right->recomputeMin();
|
|
|
|
rightmost->Splay();
|
|
rightmost->Depth = 0;
|
|
rightmost->Min = 0;
|
|
|
|
delete parent;
|
|
|
|
// Now update *our* tree
|
|
|
|
if (Father->Son == this)
|
|
Father->Son = Right;
|
|
|
|
if (Father->Son == this)
|
|
Father->Son = NULL;
|
|
else {
|
|
Left->Right = Right;
|
|
Right->Left = Left;
|
|
}
|
|
Left = Right = NULL;
|
|
Father = NULL;
|
|
}
|
|
|
|
void ETNode::setFather(ETNode *NewFather) {
|
|
ETOccurrence *rightmost;
|
|
ETOccurrence *leftpart;
|
|
ETOccurrence *NewFatherOcc;
|
|
ETOccurrence *temp;
|
|
|
|
// First update the path in the splay tree
|
|
NewFatherOcc = new ETOccurrence(NewFather);
|
|
|
|
rightmost = NewFather->RightmostOcc;
|
|
rightmost->Splay();
|
|
|
|
leftpart = rightmost->Left;
|
|
|
|
temp = RightmostOcc;
|
|
temp->Splay();
|
|
|
|
NewFatherOcc->setLeft(leftpart);
|
|
NewFatherOcc->setRight(temp);
|
|
|
|
temp->Depth++;
|
|
temp->Min++;
|
|
NewFatherOcc->recomputeMin();
|
|
|
|
rightmost->setLeft(NewFatherOcc);
|
|
|
|
if (NewFatherOcc->Min + rightmost->Depth < rightmost->Min) {
|
|
rightmost->Min = NewFatherOcc->Min + rightmost->Depth;
|
|
rightmost->MinOccurrence = NewFatherOcc->MinOccurrence;
|
|
}
|
|
|
|
delete ParentOcc;
|
|
ParentOcc = NewFatherOcc;
|
|
|
|
// Update *our* tree
|
|
ETNode *left;
|
|
ETNode *right;
|
|
|
|
Father = NewFather;
|
|
right = Father->Son;
|
|
|
|
if (right)
|
|
left = right->Left;
|
|
else
|
|
left = right = this;
|
|
|
|
left->Right = this;
|
|
right->Left = this;
|
|
Left = left;
|
|
Right = right;
|
|
|
|
Father->Son = this;
|
|
}
|
|
|
|
bool ETNode::Below(ETNode *other) {
|
|
ETOccurrence *up = other->RightmostOcc;
|
|
ETOccurrence *down = RightmostOcc;
|
|
|
|
if (this == other)
|
|
return true;
|
|
|
|
up->Splay();
|
|
|
|
ETOccurrence *left, *right;
|
|
left = up->Left;
|
|
right = up->Right;
|
|
|
|
if (!left)
|
|
return false;
|
|
|
|
left->Parent = NULL;
|
|
|
|
if (right)
|
|
right->Parent = NULL;
|
|
|
|
down->Splay();
|
|
|
|
if (left == down || left->Parent != NULL) {
|
|
if (right)
|
|
right->Parent = up;
|
|
up->setLeft(down);
|
|
} else {
|
|
left->Parent = up;
|
|
|
|
// If the two occurrences are in different trees, put things
|
|
// back the way they were.
|
|
if (right && right->Parent != NULL)
|
|
up->setRight(down);
|
|
else
|
|
up->setRight(right);
|
|
return false;
|
|
}
|
|
|
|
if (down->Depth <= 0)
|
|
return false;
|
|
|
|
return !down->Right || down->Right->Min + down->Depth >= 0;
|
|
}
|
|
|
|
ETNode *ETNode::NCA(ETNode *other) {
|
|
ETOccurrence *occ1 = RightmostOcc;
|
|
ETOccurrence *occ2 = other->RightmostOcc;
|
|
|
|
ETOccurrence *left, *right, *ret;
|
|
ETOccurrence *occmin;
|
|
int mindepth;
|
|
|
|
if (this == other)
|
|
return this;
|
|
|
|
occ1->Splay();
|
|
left = occ1->Left;
|
|
right = occ1->Right;
|
|
|
|
if (left)
|
|
left->Parent = NULL;
|
|
|
|
if (right)
|
|
right->Parent = NULL;
|
|
occ2->Splay();
|
|
|
|
if (left == occ2 || (left && left->Parent != NULL)) {
|
|
ret = occ2->Right;
|
|
|
|
occ1->setLeft(occ2);
|
|
if (right)
|
|
right->Parent = occ1;
|
|
} else {
|
|
ret = occ2->Left;
|
|
|
|
occ1->setRight(occ2);
|
|
if (left)
|
|
left->Parent = occ1;
|
|
}
|
|
|
|
if (occ2->Depth > 0) {
|
|
occmin = occ1;
|
|
mindepth = occ1->Depth;
|
|
} else {
|
|
occmin = occ2;
|
|
mindepth = occ2->Depth + occ1->Depth;
|
|
}
|
|
|
|
if (ret && ret->Min + occ1->Depth + occ2->Depth < mindepth)
|
|
return ret->MinOccurrence->OccFor;
|
|
else
|
|
return occmin->OccFor;
|
|
}
|
|
|
|
void ETNode::assignDFSNumber(int num) {
|
|
std::vector<ETNode *> workStack;
|
|
std::set<ETNode *> visitedNodes;
|
|
|
|
workStack.push_back(this);
|
|
visitedNodes.insert(this);
|
|
this->DFSNumIn = num++;
|
|
|
|
while (!workStack.empty()) {
|
|
ETNode *Node = workStack.back();
|
|
|
|
// If this is leaf node then set DFSNumOut and pop the stack
|
|
if (!Node->Son) {
|
|
Node->DFSNumOut = num++;
|
|
workStack.pop_back();
|
|
continue;
|
|
}
|
|
|
|
ETNode *son = Node->Son;
|
|
|
|
// Visit Node->Son first
|
|
if (visitedNodes.count(son) == 0) {
|
|
son->DFSNumIn = num++;
|
|
workStack.push_back(son);
|
|
visitedNodes.insert(son);
|
|
continue;
|
|
}
|
|
|
|
bool visitChild = false;
|
|
// Visit remaining children
|
|
for (ETNode *s = son->Right; s != son && !visitChild; s = s->Right) {
|
|
if (visitedNodes.count(s) == 0) {
|
|
visitChild = true;
|
|
s->DFSNumIn = num++;
|
|
workStack.push_back(s);
|
|
visitedNodes.insert(s);
|
|
}
|
|
}
|
|
|
|
if (!visitChild) {
|
|
// If we reach here means all children are visited
|
|
Node->DFSNumOut = num++;
|
|
workStack.pop_back();
|
|
}
|
|
}
|
|
}
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// ETForest implementation
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
static RegisterPass<ETForest>
|
|
D("etforest", "ET Forest Construction", true);
|
|
|
|
void ETForestBase::reset() {
|
|
for (ETMapType::iterator I = Nodes.begin(), E = Nodes.end(); I != E; ++I)
|
|
delete I->second;
|
|
Nodes.clear();
|
|
}
|
|
|
|
void ETForestBase::updateDFSNumbers()
|
|
{
|
|
int dfsnum = 0;
|
|
// Iterate over all nodes in depth first order.
|
|
for (unsigned i = 0, e = Roots.size(); i != e; ++i)
|
|
for (df_iterator<BasicBlock*> I = df_begin(Roots[i]),
|
|
E = df_end(Roots[i]); I != E; ++I) {
|
|
BasicBlock *BB = *I;
|
|
ETNode *ETN = getNode(BB);
|
|
if (ETN && !ETN->hasFather())
|
|
ETN->assignDFSNumber(dfsnum);
|
|
}
|
|
SlowQueries = 0;
|
|
DFSInfoValid = true;
|
|
}
|
|
|
|
// dominates - Return true if A dominates B. THis performs the
|
|
// special checks necessary if A and B are in the same basic block.
|
|
bool ETForestBase::dominates(Instruction *A, Instruction *B) {
|
|
BasicBlock *BBA = A->getParent(), *BBB = B->getParent();
|
|
if (BBA != BBB) return dominates(BBA, BBB);
|
|
|
|
// It is not possible to determine dominance between two PHI nodes
|
|
// based on their ordering.
|
|
if (isa<PHINode>(A) && isa<PHINode>(B))
|
|
return false;
|
|
|
|
// Loop through the basic block until we find A or B.
|
|
BasicBlock::iterator I = BBA->begin();
|
|
for (; &*I != A && &*I != B; ++I) /*empty*/;
|
|
|
|
if(!IsPostDominators) {
|
|
// A dominates B if it is found first in the basic block.
|
|
return &*I == A;
|
|
} else {
|
|
// A post-dominates B if B is found first in the basic block.
|
|
return &*I == B;
|
|
}
|
|
}
|
|
|
|
/// isReachableFromEntry - Return true if A is dominated by the entry
|
|
/// block of the function containing it.
|
|
const bool ETForestBase::isReachableFromEntry(BasicBlock* A) {
|
|
return dominates(&A->getParent()->getEntryBlock(), A);
|
|
}
|
|
|
|
ETNode *ETForest::getNodeForBlock(BasicBlock *BB) {
|
|
ETNode *&BBNode = Nodes[BB];
|
|
if (BBNode) return BBNode;
|
|
|
|
// Haven't calculated this node yet? Get or calculate the node for the
|
|
// immediate dominator.
|
|
DominatorTree::Node *node= getAnalysis<DominatorTree>().getNode(BB);
|
|
|
|
// If we are unreachable, we may not have an immediate dominator.
|
|
if (!node || !node->getIDom())
|
|
return BBNode = new ETNode(BB);
|
|
else {
|
|
ETNode *IDomNode = getNodeForBlock(node->getIDom()->getBlock());
|
|
|
|
// Add a new tree node for this BasicBlock, and link it as a child of
|
|
// IDomNode
|
|
BBNode = new ETNode(BB);
|
|
BBNode->setFather(IDomNode);
|
|
return BBNode;
|
|
}
|
|
}
|
|
|
|
void ETForest::calculate(const DominatorTree &DT) {
|
|
assert(Roots.size() == 1 && "ETForest should have 1 root block!");
|
|
BasicBlock *Root = Roots[0];
|
|
Nodes[Root] = new ETNode(Root); // Add a node for the root
|
|
|
|
Function *F = Root->getParent();
|
|
// Loop over all of the reachable blocks in the function...
|
|
for (Function::iterator I = F->begin(), E = F->end(); I != E; ++I) {
|
|
DominatorTree::Node* node = DT.getNode(I);
|
|
if (node && node->getIDom()) { // Reachable block.
|
|
BasicBlock* ImmDom = node->getIDom()->getBlock();
|
|
ETNode *&BBNode = Nodes[I];
|
|
if (!BBNode) { // Haven't calculated this node yet?
|
|
// Get or calculate the node for the immediate dominator
|
|
ETNode *IDomNode = getNodeForBlock(ImmDom);
|
|
|
|
// Add a new ETNode for this BasicBlock, and set it's parent
|
|
// to it's immediate dominator.
|
|
BBNode = new ETNode(I);
|
|
BBNode->setFather(IDomNode);
|
|
}
|
|
}
|
|
}
|
|
|
|
// Make sure we've got nodes around for every block
|
|
for (Function::iterator I = F->begin(), E = F->end(); I != E; ++I) {
|
|
ETNode *&BBNode = Nodes[I];
|
|
if (!BBNode)
|
|
BBNode = new ETNode(I);
|
|
}
|
|
|
|
updateDFSNumbers ();
|
|
}
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// ETForestBase Implementation
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
void ETForestBase::addNewBlock(BasicBlock *BB, BasicBlock *IDom) {
|
|
ETNode *&BBNode = Nodes[BB];
|
|
assert(!BBNode && "BasicBlock already in ET-Forest");
|
|
|
|
BBNode = new ETNode(BB);
|
|
BBNode->setFather(getNode(IDom));
|
|
DFSInfoValid = false;
|
|
}
|
|
|
|
void ETForestBase::setImmediateDominator(BasicBlock *BB, BasicBlock *newIDom) {
|
|
assert(getNode(BB) && "BasicBlock not in ET-Forest");
|
|
assert(getNode(newIDom) && "IDom not in ET-Forest");
|
|
|
|
ETNode *Node = getNode(BB);
|
|
if (Node->hasFather()) {
|
|
if (Node->getFather()->getData<BasicBlock>() == newIDom)
|
|
return;
|
|
Node->Split();
|
|
}
|
|
Node->setFather(getNode(newIDom));
|
|
DFSInfoValid= false;
|
|
}
|
|
|
|
void ETForestBase::print(std::ostream &o, const Module *) const {
|
|
o << "=============================--------------------------------\n";
|
|
o << "ET Forest:\n";
|
|
o << "DFS Info ";
|
|
if (DFSInfoValid)
|
|
o << "is";
|
|
else
|
|
o << "is not";
|
|
o << " up to date\n";
|
|
|
|
Function *F = getRoots()[0]->getParent();
|
|
for (Function::iterator I = F->begin(), E = F->end(); I != E; ++I) {
|
|
o << " DFS Numbers For Basic Block:";
|
|
WriteAsOperand(o, I, false);
|
|
o << " are:";
|
|
if (ETNode *EN = getNode(I)) {
|
|
o << "In: " << EN->getDFSNumIn();
|
|
o << " Out: " << EN->getDFSNumOut() << "\n";
|
|
} else {
|
|
o << "No associated ETNode";
|
|
}
|
|
o << "\n";
|
|
}
|
|
o << "\n";
|
|
}
|