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Template-ize more of the DomTree internal implementation details. Only the calculate() methods for DomTree and PostDomTree remain to be merged/template-ized.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@42476 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Owen Anderson 2007-09-30 04:17:16 +00:00
parent c28476f1d9
commit ab528fe0fb
5 changed files with 145 additions and 156 deletions
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135
include/llvm/Analysis/DominatorInternals.h
View File

@ -6,17 +6,31 @@
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines shared implementation details of dominator and
// postdominator calculation. This file SHOULD NOT BE INCLUDED outside
// of the dominator and postdominator implementation files.
//
//===----------------------------------------------------------------------===//
#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 {
@ -85,6 +99,115 @@ unsigned DFSPass(DominatorTreeBase& DT, typename GraphT::NodeType* V,
return N;
}
template<class GraphT>
void Compress(DominatorTreeBase& DT, typename GraphT::NodeType *VIn) {
std::vector<typename GraphT::NodeType*> Work;
SmallPtrSet<typename GraphT::NodeType*, 32> Visited;
typename GraphT::NodeType* VInAncestor = DT.Info[VIn].Ancestor;
DominatorTreeBase::InfoRec &VInVAInfo = DT.Info[VInAncestor];
if (VInVAInfo.Ancestor != 0)
Work.push_back(VIn);
while (!Work.empty()) {
typename GraphT::NodeType* V = Work.back();
DominatorTree::InfoRec &VInfo = DT.Info[V];
typename GraphT::NodeType* 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;
typename GraphT::NodeType* VAncestorLabel = VAInfo.Label;
typename GraphT::NodeType* VLabel = VInfo.Label;
if (DT.Info[VAncestorLabel].Semi < DT.Info[VLabel].Semi)
VInfo.Label = VAncestorLabel;
VInfo.Ancestor = VAInfo.Ancestor;
}
}
template<class GraphT>
typename GraphT::NodeType* Eval(DominatorTreeBase& DT,
typename GraphT::NodeType *V) {
DominatorTreeBase::InfoRec &VInfo = DT.Info[V];
#if !BALANCE_IDOM_TREE
// Higher-complexity but faster implementation
if (VInfo.Ancestor == 0)
return V;
Compress<GraphT>(DT, V);
return VInfo.Label;
#else
// Lower-complexity but slower implementation
if (VInfo.Ancestor == 0)
return VInfo.Label;
Compress<GraphT>(DT, V);
GraphT::NodeType* VLabel = VInfo.Label;
GraphT::NodeType* VAncestorLabel = DT.Info[VInfo.Ancestor].Label;
if (DT.Info[VAncestorLabel].Semi >= DT.Info[VLabel].Semi)
return VLabel;
else
return VAncestorLabel;
#endif
}
template<class GraphT>
void Link(DominatorTreeBase& DT, typename GraphT::NodeType* V,
typename GraphT::NodeType* W, DominatorTreeBase::InfoRec &WInfo) {
#if !BALANCE_IDOM_TREE
// Higher-complexity but faster implementation
WInfo.Ancestor = V;
#else
// Lower-complexity but slower implementation
GraphT::NodeType* WLabel = WInfo.Label;
unsigned WLabelSemi = DT.Info[WLabel].Semi;
GraphT::NodeType* S = W;
InfoRec *SInfo = &DT.Info[S];
GraphT::NodeType* SChild = SInfo->Child;
InfoRec *SChildInfo = &DT.Info[SChild];
while (WLabelSemi < DT.Info[SChildInfo->Label].Semi) {
GraphT::NodeType* 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

13
include/llvm/Analysis/Dominators.h
View File

@ -275,10 +275,15 @@ 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);
template<class GraphT> friend void Compress(DominatorTreeBase& DT,
typename GraphT::NodeType* VIn);
template<class GraphT> friend typename GraphT::NodeType* Eval(
DominatorTreeBase& DT,
typename GraphT::NodeType* V);
template<class GraphT> friend void Link(DominatorTreeBase& DT,
typename GraphT::NodeType* V,
typename GraphT::NodeType* W,
InfoRec &WInfo);
template<class GraphT> friend unsigned DFSPass(DominatorTreeBase& DT,
typename GraphT::NodeType* V,

7
lib/Analysis/PostDominatorCalculation.h
View File

@ -50,7 +50,8 @@ 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[Eval(PDT, *SI)].Semi;
unsigned SemiU =
PDT.Info[Eval<GraphTraits<Inverse<BasicBlock*> > >(PDT, *SI)].Semi;
if (SemiU < WInfo.Semi)
WInfo.Semi = SemiU;
}
@ -58,14 +59,14 @@ void PDTcalculate(PostDominatorTree& PDT, Function &F) {
PDT.Info[PDT.Vertex[WInfo.Semi]].Bucket.push_back(W);
BasicBlock *WParent = WInfo.Parent;
Link(PDT, WParent, W, WInfo);
Link<GraphTraits<Inverse<BasicBlock*> > >(PDT, WParent, W, WInfo);
// Step #3: Implicitly define the immediate dominator of vertices
std::vector<BasicBlock*> &WParentBucket = PDT.Info[WParent].Bucket;
while (!WParentBucket.empty()) {
BasicBlock *V = WParentBucket.back();
WParentBucket.pop_back();
BasicBlock *U = Eval(PDT, V);
BasicBlock *U = Eval<GraphTraits<Inverse<BasicBlock*> > >(PDT, V);
PDT.IDoms[V] = PDT.Info[U].Semi < PDT.Info[V].Semi ? U : WParent;
}
}

6
lib/VMCore/DominatorCalculation.h
View File

@ -53,7 +53,7 @@ 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[Eval(DT, *PI)].Semi;
unsigned SemiU = DT.Info[Eval<GraphTraits<BasicBlock*> >(DT, *PI)].Semi;
if (SemiU < WInfo.Semi)
WInfo.Semi = SemiU;
}
@ -61,14 +61,14 @@ void DTcalculate(DominatorTree& DT, Function &F) {
DT.Info[DT.Vertex[WInfo.Semi]].Bucket.push_back(W);
BasicBlock *WParent = WInfo.Parent;
Link(DT, WParent, W, WInfo);
Link<GraphTraits<BasicBlock*> >(DT, WParent, W, WInfo);
// Step #3: Implicitly define the immediate dominator of vertices
std::vector<BasicBlock*> &WParentBucket = DT.Info[WParent].Bucket;
while (!WParentBucket.empty()) {
BasicBlock *V = WParentBucket.back();
WParentBucket.pop_back();
BasicBlock *U = Eval(DT, V);
BasicBlock *U = Eval<GraphTraits<BasicBlock*> >(DT, V);
DT.IDoms[V] = DT.Info[U].Semi < DT.Info[V].Semi ? U : WParent;
}
}

140
lib/VMCore/DominatorInternals.cpp
View File

@ -1,140 +0,0 @@
//==- 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.
//
//===----------------------------------------------------------------------===//
#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<BasicBlock *> Work;
SmallPtrSet<BasicBlock *, 32> 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
}
}