maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity

Completely merge the implementation details of DomTree and PostDomTree. 

Also, add a FIXME for a bug in PostDomTree calculation I noticed while writing this,

llvm-svn: 42593
This commit is contained in:
Owen Anderson 2007-10-03 21:25:45 +00:00
parent 87337924d5
commit 8313e75ea7
7 changed files with 97 additions and 214 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

87
llvm/include/llvm/Analysis/DominatorInternals.h
View File

@ -208,6 +208,93 @@ void Link(DominatorTreeBase& DT, typename GraphT::NodeType* V,
#endif
}
template<class NodeT>
void Calculate(DominatorTreeBase& DT, Function& F) {
// 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)
N = DFSPass<GraphTraits<NodeT> >(DT, DT.Roots[i], N);
for (unsigned i = N; i >= 2; --i) {
typename GraphTraits<NodeT>::NodeType* W = DT.Vertex[i];
DominatorTree::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<GraphTraits<NodeT> >(DT, *CI)].Semi;
if (SemiU < WInfo.Semi)
WInfo.Semi = SemiU;
}
DT.Info[DT.Vertex[WInfo.Semi]].Bucket.push_back(W);
typename GraphTraits<NodeT>::NodeType* WParent = WInfo.Parent;
Link<GraphTraits<NodeT> >(DT, WParent, W, WInfo);
// Step #3: Implicitly define the immediate dominator of vertices
std::vector<typename GraphTraits<NodeT>::NodeType*> &WParentBucket =
DT.Info[WParent].Bucket;
while (!WParentBucket.empty()) {
typename GraphTraits<NodeT>::NodeType* V = WParentBucket.back();
WParentBucket.pop_back();
typename GraphTraits<NodeT>::NodeType* U =
Eval<GraphTraits<NodeT> >(DT, V);
DT.IDoms[V] = DT.Info[U].Semi < DT.Info[V].Semi ? U : WParent;
}
}
// Step #4: Explicitly define the immediate dominator of each vertex
for (unsigned i = 2; i <= N; ++i) {
typename GraphTraits<NodeT>::NodeType* W = DT.Vertex[i];
typename GraphTraits<NodeT>::NodeType*& WIDom = DT.IDoms[W];
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 GraphTraits<NodeT>::NodeType* Root = DT.Roots.size() == 1 ? DT.Roots[0]
: 0;
DT.DomTreeNodes[Root] = DT.RootNode = new DomTreeNode(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 GraphTraits<NodeT>::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);
}
// Free temporary memory used to construct idom's
DT.IDoms.clear();
DT.Info.clear();
std::vector<typename GraphTraits<NodeT>::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;
}
}
#endif

6
llvm/include/llvm/Analysis/Dominators.h
View File

@ -289,6 +289,9 @@ protected:
typename GraphT::NodeType* V,
unsigned N);
template<class NodeT> friend void Calculate(DominatorTreeBase& DT,
Function& F);
/// updateDFSNumbers - Assign In and Out numbers to the nodes while walking
/// dominator tree in dfs order.
void updateDFSNumbers();
@ -325,9 +328,6 @@ public:
/// BB is split and now it has one successor. Update dominator tree to
/// reflect this change.
void splitBlock(BasicBlock *BB);
private:
friend void DTcalculate(DominatorTree& DT, Function& F);
};
//===-------------------------------------

2
llvm/include/llvm/Analysis/PostDominators.h
View File

@ -32,8 +32,6 @@ struct PostDominatorTree : public DominatorTreeBase {
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
}
private:
friend void PDTcalculate(PostDominatorTree& PDT, Function &F);
};

99
llvm/lib/Analysis/PostDominatorCalculation.h
View File

@ -1,99 +0,0 @@
//==- PostDominatorCalculation.h - Post-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.
//
//===----------------------------------------------------------------------===//
//
// PostDominatorTree calculation implementation.
//===----------------------------------------------------------------------===//
#ifndef LLVM_ANALYSIS_POST_DOMINATOR_CALCULATION_H
#define LLVM_ANALYSIS_POST_DOMINATOR_CALCULATION_H
#include "llvm/Analysis/PostDominators.h"
#include "llvm/Analysis/DominatorInternals.h"
namespace llvm {
void PDTcalculate(PostDominatorTree& PDT, Function &F) {
// 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 = PDT.Roots.size(); i != e; ++i)
N = DFSPass<GraphTraits<Inverse<BasicBlock*> > >(PDT, PDT.Roots[i], N);
for (unsigned i = N; i >= 2; --i) {
BasicBlock *W = PDT.Vertex[i];
PostDominatorTree::InfoRec &WInfo = PDT.Info[W];
// 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<GraphTraits<Inverse<BasicBlock*> > >(PDT, *SI)].Semi;
if (SemiU < WInfo.Semi)
WInfo.Semi = SemiU;
}
PDT.Info[PDT.Vertex[WInfo.Semi]].Bucket.push_back(W);
BasicBlock *WParent = WInfo.Parent;
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<GraphTraits<Inverse<BasicBlock*> > >(PDT, V);
PDT.IDoms[V] = PDT.Info[U].Semi < PDT.Info[V].Semi ? U : WParent;
}
}
// Step #4: Explicitly define the immediate dominator of each vertex
for (unsigned i = 2; i <= N; ++i) {
BasicBlock *W = PDT.Vertex[i];
BasicBlock *&WIDom = PDT.IDoms[W];
if (WIDom != PDT.Vertex[PDT.Info[W].Semi])
WIDom = PDT.IDoms[WIDom];
}
if (PDT.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.
BasicBlock *Root = PDT.Roots.size() == 1 ? PDT.Roots[0] : 0;
PDT.DomTreeNodes[Root] = PDT.RootNode = new DomTreeNode(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 (BasicBlock *ImmPostDom = PDT.getIDom(I)) { // Reachable block.
DomTreeNode *&BBNode = PDT.DomTreeNodes[I];
if (!BBNode) { // Haven't calculated this node yet?
// Get or calculate the node for the immediate dominator
DomTreeNode *IPDomNode = PDT.getNodeForBlock(ImmPostDom);
// Add a new tree node for this BasicBlock, and link it as a child of
// IDomNode
DomTreeNode *C = new DomTreeNode(I, IPDomNode);
PDT.DomTreeNodes[I] = C;
BBNode = IPDomNode->addChild(C);
}
}
// Free temporary memory used to construct idom's
PDT.IDoms.clear();
PDT.Info.clear();
std::vector<BasicBlock*>().swap(PDT.Vertex);
// Start out with the DFS numbers being invalid. Let them be computed if
// demanded.
PDT.DFSInfoValid = false;
}
}
#endif

4
llvm/lib/Analysis/PostDominators.cpp
View File

@ -16,7 +16,7 @@
#include "llvm/Support/CFG.h"
#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/ADT/SetOperations.h"
#include "PostDominatorCalculation.h"
#include "llvm/Analysis/DominatorInternals.h"
using namespace llvm;
//===----------------------------------------------------------------------===//
@ -47,7 +47,7 @@ bool PostDominatorTree::runOnFunction(Function &F) {
Vertex.push_back(0);
PDTcalculate(*this, F);
Calculate<Inverse<BasicBlock*> >(*this, F);
return false;
}

106
llvm/lib/VMCore/DominatorCalculation.h
View File

@ -1,106 +0,0 @@
//==- DominatorCalculation.h - 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_VMCORE_DOMINATOR_CALCULATION_H
#define LLVM_VMCORE_DOMINATOR_CALCULATION_H
#include "llvm/Analysis/Dominators.h"
#include "llvm/Analysis/DominatorInternals.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 DTcalculate(DominatorTree& DT, Function &F) {
BasicBlock* Root = DT.Roots[0];
// Add a node for the root...
DT.DomTreeNodes[Root] = DT.RootNode = new DomTreeNode(Root, 0);
// Step #1: Number blocks in depth-first order and initialize variables used
// in later stages of the algorithm.
unsigned N = DFSPass<GraphTraits<BasicBlock*> >(DT, Root, 0);
for (unsigned i = N; i >= 2; --i) {
BasicBlock *W = DT.Vertex[i];
DominatorTree::InfoRec &WInfo = DT.Info[W];
// 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<GraphTraits<BasicBlock*> >(DT, *PI)].Semi;
if (SemiU < WInfo.Semi)
WInfo.Semi = SemiU;
}
DT.Info[DT.Vertex[WInfo.Semi]].Bucket.push_back(W);
BasicBlock *WParent = WInfo.Parent;
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<GraphTraits<BasicBlock*> >(DT, V);
DT.IDoms[V] = DT.Info[U].Semi < DT.Info[V].Semi ? U : WParent;
}
}
// Step #4: Explicitly define the immediate dominator of each vertex
for (unsigned i = 2; i <= N; ++i) {
BasicBlock *W = DT.Vertex[i];
BasicBlock *&WIDom = DT.IDoms[W];
if (WIDom != DT.Vertex[DT.Info[W].Semi])
WIDom = DT.IDoms[WIDom];
}
// Loop over all of the reachable blocks in the function...
for (Function::iterator I = F.begin(), E = F.end(); I != E; ++I)
if (BasicBlock *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);
}
// Free temporary memory used to construct idom's
DT.Info.clear();
DT.IDoms.clear();
std::vector<BasicBlock*>().swap(DT.Vertex);
DT.updateDFSNumbers();
}
}
#endif

7
llvm/lib/VMCore/Dominators.cpp
View File

@ -21,9 +21,9 @@
#include "llvm/ADT/SetOperations.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/Analysis/DominatorInternals.h"
#include "llvm/Instructions.h"
#include "llvm/Support/Streams.h"
#include "DominatorCalculation.h"
#include <algorithm>
using namespace llvm;
@ -357,7 +357,10 @@ bool DominatorTree::runOnFunction(Function &F) {
DomTreeNodes[&F.getEntryBlock()] = 0;
Vertex.push_back(0);
DTcalculate(*this, F);
Calculate<BasicBlock*>(*this, F);
updateDFSNumbers();
return false;
}