diff --git a/include/llvm/Analysis/Dominators.h b/include/llvm/Analysis/Dominators.h index f4c31a5f161..b9c85b5339f 100644 --- a/include/llvm/Analysis/Dominators.h +++ b/include/llvm/Analysis/Dominators.h @@ -275,6 +275,11 @@ public: virtual void dump(); protected: + friend void Compress(DominatorTreeBase& DT, BasicBlock *VIn); + friend BasicBlock *Eval(DominatorTreeBase& DT, BasicBlock *V); + friend void Link(DominatorTreeBase& DT, BasicBlock *V, + BasicBlock *W, InfoRec &WInfo); + /// updateDFSNumbers - Assign In and Out numbers to the nodes while walking /// dominator tree in dfs order. void updateDFSNumbers(); @@ -314,10 +319,6 @@ public: private: friend void DTcalculate(DominatorTree& DT, Function& F); - friend void DTCompress(DominatorTree& DT, BasicBlock *VIn); - friend BasicBlock *DTEval(DominatorTree& DT, BasicBlock *v); - friend void DTLink(DominatorTree& DT, BasicBlock *V, - BasicBlock *W, InfoRec &WInfo); unsigned DFSPass(BasicBlock *V, unsigned N); }; diff --git a/include/llvm/Analysis/PostDominators.h b/include/llvm/Analysis/PostDominators.h index 06a42dac38d..b2a37ffdb06 100644 --- a/include/llvm/Analysis/PostDominators.h +++ b/include/llvm/Analysis/PostDominators.h @@ -39,9 +39,6 @@ struct PostDominatorTree : public DominatorTreeBase { private: unsigned DFSPass(BasicBlock *V, unsigned N); friend void PDTcalculate(PostDominatorTree& PDT, Function &F); - friend void PDTCompress(PostDominatorTree& PDT, BasicBlock *V, - InfoRec &VInfo); - friend BasicBlock *PDTEval(PostDominatorTree& PDT, BasicBlock *V); friend void PDTLink(PostDominatorTree& PDT,BasicBlock *V, BasicBlock *W, InfoRec &WInfo); }; diff --git a/lib/Analysis/PostDominatorCalculation.h b/lib/Analysis/PostDominatorCalculation.h index 0240c44d977..01dee0dcf3d 100644 --- a/lib/Analysis/PostDominatorCalculation.h +++ b/lib/Analysis/PostDominatorCalculation.h @@ -17,39 +17,6 @@ namespace llvm { -void PDTCompress(PostDominatorTree& PDT, BasicBlock *V, - PostDominatorTree::InfoRec &VInfo) { - BasicBlock *VAncestor = VInfo.Ancestor; - PostDominatorTree::InfoRec &VAInfo = PDT.Info[VAncestor]; - if (VAInfo.Ancestor == 0) - return; - - PDTCompress(PDT, VAncestor, VAInfo); - - BasicBlock *VAncestorLabel = VAInfo.Label; - BasicBlock *VLabel = VInfo.Label; - if (PDT.Info[VAncestorLabel].Semi < PDT.Info[VLabel].Semi) - VInfo.Label = VAncestorLabel; - - VInfo.Ancestor = VAInfo.Ancestor; -} - -BasicBlock *PDTEval(PostDominatorTree& PDT, BasicBlock *V) { - PostDominatorTree::InfoRec &VInfo = PDT.Info[V]; - - // Higher-complexity but faster implementation - if (VInfo.Ancestor == 0) - return V; - PDTCompress(PDT, V, VInfo); - return VInfo.Label; -} - -void PDTLink(PostDominatorTree& PDT, BasicBlock *V, BasicBlock *W, - PostDominatorTree::InfoRec &WInfo) { - // Higher-complexity but faster implementation - WInfo.Ancestor = V; -} - void PDTcalculate(PostDominatorTree& PDT, Function &F) { // Step #0: Scan the function looking for the root nodes of the post-dominance // relationships. These blocks, which have no successors, end with return and @@ -82,7 +49,7 @@ void PDTcalculate(PostDominatorTree& PDT, Function &F) { // Step #2: Calculate the semidominators of all vertices for (succ_iterator SI = succ_begin(W), SE = succ_end(W); SI != SE; ++SI) if (PDT.Info.count(*SI)) { // Only if this predecessor is reachable! - unsigned SemiU = PDT.Info[PDTEval(PDT, *SI)].Semi; + unsigned SemiU = PDT.Info[Eval(PDT, *SI)].Semi; if (SemiU < WInfo.Semi) WInfo.Semi = SemiU; } @@ -90,14 +57,14 @@ void PDTcalculate(PostDominatorTree& PDT, Function &F) { PDT.Info[PDT.Vertex[WInfo.Semi]].Bucket.push_back(W); BasicBlock *WParent = WInfo.Parent; - PDTLink(PDT, WParent, W, WInfo); + Link(PDT, WParent, W, WInfo); // Step #3: Implicitly define the immediate dominator of vertices std::vector &WParentBucket = PDT.Info[WParent].Bucket; while (!WParentBucket.empty()) { BasicBlock *V = WParentBucket.back(); WParentBucket.pop_back(); - BasicBlock *U = PDTEval(PDT, V); + BasicBlock *U = Eval(PDT, V); PDT.IDoms[V] = PDT.Info[U].Semi < PDT.Info[V].Semi ? U : WParent; } } diff --git a/lib/VMCore/DominatorCalculation.h b/lib/VMCore/DominatorCalculation.h index ee7e674ac3f..de915be7904 100644 --- a/lib/VMCore/DominatorCalculation.h +++ b/lib/VMCore/DominatorCalculation.h @@ -33,112 +33,6 @@ namespace llvm { -void DTCompress(DominatorTree& DT, BasicBlock *VIn) { - - std::vector Work; - SmallPtrSet Visited; - BasicBlock *VInAncestor = DT.Info[VIn].Ancestor; - DominatorTree::InfoRec &VInVAInfo = DT.Info[VInAncestor]; - - if (VInVAInfo.Ancestor != 0) - Work.push_back(VIn); - - while (!Work.empty()) { - BasicBlock *V = Work.back(); - DominatorTree::InfoRec &VInfo = DT.Info[V]; - BasicBlock *VAncestor = VInfo.Ancestor; - DominatorTree::InfoRec &VAInfo = DT.Info[VAncestor]; - - // Process Ancestor first - if (Visited.insert(VAncestor) && - VAInfo.Ancestor != 0) { - Work.push_back(VAncestor); - continue; - } - Work.pop_back(); - - // Update VInfo based on Ancestor info - if (VAInfo.Ancestor == 0) - continue; - BasicBlock *VAncestorLabel = VAInfo.Label; - BasicBlock *VLabel = VInfo.Label; - if (DT.Info[VAncestorLabel].Semi < DT.Info[VLabel].Semi) - VInfo.Label = VAncestorLabel; - VInfo.Ancestor = VAInfo.Ancestor; - } -} - -BasicBlock *DTEval(DominatorTree& DT, BasicBlock *V) { - DominatorTree::InfoRec &VInfo = DT.Info[V]; -#if !BALANCE_IDOM_TREE - // Higher-complexity but faster implementation - if (VInfo.Ancestor == 0) - return V; - DTCompress(DT, V); - return VInfo.Label; -#else - // Lower-complexity but slower implementation - if (VInfo.Ancestor == 0) - return VInfo.Label; - DTCompress(DT, V); - BasicBlock *VLabel = VInfo.Label; - - BasicBlock *VAncestorLabel = DT.Info[VInfo.Ancestor].Label; - if (DT.Info[VAncestorLabel].Semi >= DT.Info[VLabel].Semi) - return VLabel; - else - return VAncestorLabel; -#endif -} - -void DTLink(DominatorTree& DT, BasicBlock *V, BasicBlock *W, - DominatorTree::InfoRec &WInfo) { -#if !BALANCE_IDOM_TREE - // Higher-complexity but faster implementation - WInfo.Ancestor = V; -#else - // Lower-complexity but slower implementation - BasicBlock *WLabel = WInfo.Label; - unsigned WLabelSemi = Info[WLabel].Semi; - BasicBlock *S = W; - InfoRec *SInfo = &Info[S]; - - BasicBlock *SChild = SInfo->Child; - InfoRec *SChildInfo = &Info[SChild]; - - while (WLabelSemi < Info[SChildInfo->Label].Semi) { - BasicBlock *SChildChild = SChildInfo->Child; - if (SInfo->Size+Info[SChildChild].Size >= 2*SChildInfo->Size) { - SChildInfo->Ancestor = S; - SInfo->Child = SChild = SChildChild; - SChildInfo = &Info[SChild]; - } else { - SChildInfo->Size = SInfo->Size; - S = SInfo->Ancestor = SChild; - SInfo = SChildInfo; - SChild = SChildChild; - SChildInfo = &Info[SChild]; - } - } - - InfoRec &VInfo = Info[V]; - SInfo->Label = WLabel; - - assert(V != W && "The optimization here will not work in this case!"); - unsigned WSize = WInfo.Size; - unsigned VSize = (VInfo.Size += WSize); - - if (VSize < 2*WSize) - std::swap(S, VInfo.Child); - - while (S) { - SInfo = &Info[S]; - SInfo->Ancestor = V; - S = SInfo->Child; - } -#endif -} - void DTcalculate(DominatorTree& DT, Function &F) { BasicBlock* Root = DT.Roots[0]; @@ -158,7 +52,7 @@ void DTcalculate(DominatorTree& DT, Function &F) { // Step #2: Calculate the semidominators of all vertices for (pred_iterator PI = pred_begin(W), E = pred_end(W); PI != E; ++PI) if (DT.Info.count(*PI)) { // Only if this predecessor is reachable! - unsigned SemiU = DT.Info[DTEval(DT, *PI)].Semi; + unsigned SemiU = DT.Info[Eval(DT, *PI)].Semi; if (SemiU < WInfo.Semi) WInfo.Semi = SemiU; } @@ -166,14 +60,14 @@ void DTcalculate(DominatorTree& DT, Function &F) { DT.Info[DT.Vertex[WInfo.Semi]].Bucket.push_back(W); BasicBlock *WParent = WInfo.Parent; - DTLink(DT, WParent, W, WInfo); + Link(DT, WParent, W, WInfo); // Step #3: Implicitly define the immediate dominator of vertices std::vector &WParentBucket = DT.Info[WParent].Bucket; while (!WParentBucket.empty()) { BasicBlock *V = WParentBucket.back(); WParentBucket.pop_back(); - BasicBlock *U = DTEval(DT, V); + BasicBlock *U = Eval(DT, V); DT.IDoms[V] = DT.Info[U].Semi < DT.Info[V].Semi ? U : WParent; } } diff --git a/lib/VMCore/DominatorInternals.cpp b/lib/VMCore/DominatorInternals.cpp new file mode 100644 index 00000000000..b7c8d32d3de --- /dev/null +++ b/lib/VMCore/DominatorInternals.cpp @@ -0,0 +1,145 @@ +//==- DominatorInternals.cpp - Dominator Calculation -------------*- C++ -*-==// +// +// 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. +// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_ANALYSIS_DOMINATOR_INTERNALS_H +#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 +// information for a flow-graph based on the algorithm described in this +// document: +// +// A Fast Algorithm for Finding Dominators in a Flowgraph +// T. Lengauer & R. Tarjan, ACM TOPLAS July 1979, pgs 121-141. +// +// This implements both the O(n*ack(n)) and the O(n*log(n)) versions of EVAL and +// LINK, but it turns out that the theoretically slower O(n*log(n)) +// implementation is actually faster than the "efficient" algorithm (even for +// large CFGs) because the constant overheads are substantially smaller. The +// lower-complexity version can be enabled with the following #define: +// +#define BALANCE_IDOM_TREE 0 +// +//===----------------------------------------------------------------------===// + +namespace llvm { + +void Compress(DominatorTreeBase& DT, BasicBlock *VIn) { + + std::vector Work; + SmallPtrSet Visited; + BasicBlock *VInAncestor = DT.Info[VIn].Ancestor; + DominatorTreeBase::InfoRec &VInVAInfo = DT.Info[VInAncestor]; + + if (VInVAInfo.Ancestor != 0) + Work.push_back(VIn); + + while (!Work.empty()) { + BasicBlock *V = Work.back(); + DominatorTree::InfoRec &VInfo = DT.Info[V]; + BasicBlock *VAncestor = VInfo.Ancestor; + DominatorTreeBase::InfoRec &VAInfo = DT.Info[VAncestor]; + + // Process Ancestor first + if (Visited.insert(VAncestor) && + VAInfo.Ancestor != 0) { + Work.push_back(VAncestor); + continue; + } + Work.pop_back(); + + // Update VInfo based on Ancestor info + if (VAInfo.Ancestor == 0) + continue; + BasicBlock *VAncestorLabel = VAInfo.Label; + BasicBlock *VLabel = VInfo.Label; + if (DT.Info[VAncestorLabel].Semi < DT.Info[VLabel].Semi) + VInfo.Label = VAncestorLabel; + VInfo.Ancestor = VAInfo.Ancestor; + } +} + +BasicBlock *Eval(DominatorTreeBase& DT, BasicBlock *V) { + DominatorTreeBase::InfoRec &VInfo = DT.Info[V]; +#if !BALANCE_IDOM_TREE + // Higher-complexity but faster implementation + if (VInfo.Ancestor == 0) + return V; + Compress(DT, V); + return VInfo.Label; +#else + // Lower-complexity but slower implementation + if (VInfo.Ancestor == 0) + return VInfo.Label; + Compress(DT, V); + BasicBlock *VLabel = VInfo.Label; + + BasicBlock *VAncestorLabel = DT.Info[VInfo.Ancestor].Label; + if (DT.Info[VAncestorLabel].Semi >= DT.Info[VLabel].Semi) + return VLabel; + else + return VAncestorLabel; +#endif +} + +void Link(DominatorTreeBase& DT, BasicBlock *V, BasicBlock *W, + DominatorTreeBase::InfoRec &WInfo) { +#if !BALANCE_IDOM_TREE + // Higher-complexity but faster implementation + WInfo.Ancestor = V; +#else + // Lower-complexity but slower implementation + BasicBlock *WLabel = WInfo.Label; + unsigned WLabelSemi = DT.Info[WLabel].Semi; + BasicBlock *S = W; + InfoRec *SInfo = &DT.Info[S]; + + BasicBlock *SChild = SInfo->Child; + InfoRec *SChildInfo = &DT.Info[SChild]; + + while (WLabelSemi < DT.Info[SChildInfo->Label].Semi) { + BasicBlock *SChildChild = SChildInfo->Child; + if (SInfo->Size+DT.Info[SChildChild].Size >= 2*SChildInfo->Size) { + SChildInfo->Ancestor = S; + SInfo->Child = SChild = SChildChild; + SChildInfo = &DT.Info[SChild]; + } else { + SChildInfo->Size = SInfo->Size; + S = SInfo->Ancestor = SChild; + SInfo = SChildInfo; + SChild = SChildChild; + SChildInfo = &DT.Info[SChild]; + } + } + + DominatorTreeBase::InfoRec &VInfo = DT.Info[V]; + SInfo->Label = WLabel; + + assert(V != W && "The optimization here will not work in this case!"); + unsigned WSize = WInfo.Size; + unsigned VSize = (VInfo.Size += WSize); + + if (VSize < 2*WSize) + std::swap(S, VInfo.Child); + + while (S) { + SInfo = &DT.Info[S]; + SInfo->Ancestor = V; + S = SInfo->Child; + } +#endif +} + +} + +#endif \ No newline at end of file