Factor the calculation details for PostDomTree out of PostDominators.cpp and

into a separate header file.

Next step: merging PostDominatorCalculation.h with DominatorCalculation.h.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@42251 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Owen Anderson 2007-09-23 22:21:00 +00:00
parent eefb31094f
commit 04fa569320
3 changed files with 156 additions and 147 deletions

View File

@ -29,7 +29,7 @@ struct PostDominatorTree : public DominatorTreeBase {
virtual bool runOnFunction(Function &F) {
reset(); // Reset from the last time we were run...
calculate(F);
PDTcalculate(*this, F);
return false;
}
@ -37,11 +37,13 @@ struct PostDominatorTree : public DominatorTreeBase {
AU.setPreservesAll();
}
private:
void calculate(Function &F);
unsigned DFSPass(BasicBlock *V, unsigned N);
void Compress(BasicBlock *V, InfoRec &VInfo);
BasicBlock *Eval(BasicBlock *V);
void Link(BasicBlock *V, BasicBlock *W, InfoRec &WInfo);
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);
};

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@ -0,0 +1,148 @@
//==- 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"
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
// unwind instructions.
for (Function::iterator I = F.begin(), E = F.end(); I != E; ++I) {
TerminatorInst *Insn = I->getTerminator();
if (Insn->getNumSuccessors() == 0) {
// Unreachable block is not a root node.
if (!isa<UnreachableInst>(Insn))
PDT.Roots.push_back(I);
}
// Prepopulate maps so that we don't get iterator invalidation issues later.
PDT.IDoms[I] = 0;
PDT.DomTreeNodes[I] = 0;
}
PDT.Vertex.push_back(0);
// 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 = PDT.DFSPass(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[PDTEval(PDT, *SI)].Semi;
if (SemiU < WInfo.Semi)
WInfo.Semi = SemiU;
}
PDT.Info[PDT.Vertex[WInfo.Semi]].Bucket.push_back(W);
BasicBlock *WParent = WInfo.Parent;
PDTLink(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 = PDTEval(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

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@ -16,6 +16,7 @@
#include "llvm/Support/CFG.h"
#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/ADT/SetOperations.h"
#include "PostDominatorCalculation.h"
using namespace llvm;
//===----------------------------------------------------------------------===//
@ -72,148 +73,6 @@ unsigned PostDominatorTree::DFSPass(BasicBlock *V, unsigned N) {
return N;
}
void PostDominatorTree::Compress(BasicBlock *V, InfoRec &VInfo) {
BasicBlock *VAncestor = VInfo.Ancestor;
InfoRec &VAInfo = Info[VAncestor];
if (VAInfo.Ancestor == 0)
return;
Compress(VAncestor, VAInfo);
BasicBlock *VAncestorLabel = VAInfo.Label;
BasicBlock *VLabel = VInfo.Label;
if (Info[VAncestorLabel].Semi < Info[VLabel].Semi)
VInfo.Label = VAncestorLabel;
VInfo.Ancestor = VAInfo.Ancestor;
}
BasicBlock *PostDominatorTree::Eval(BasicBlock *V) {
InfoRec &VInfo = Info[V];
// Higher-complexity but faster implementation
if (VInfo.Ancestor == 0)
return V;
Compress(V, VInfo);
return VInfo.Label;
}
void PostDominatorTree::Link(BasicBlock *V, BasicBlock *W,
InfoRec &WInfo) {
// Higher-complexity but faster implementation
WInfo.Ancestor = V;
}
void PostDominatorTree::calculate(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
// unwind instructions.
for (Function::iterator I = F.begin(), E = F.end(); I != E; ++I) {
TerminatorInst *Insn = I->getTerminator();
if (Insn->getNumSuccessors() == 0) {
// Unreachable block is not a root node.
if (!isa<UnreachableInst>(Insn))
Roots.push_back(I);
}
// Prepopulate maps so that we don't get iterator invalidation issues later.
IDoms[I] = 0;
DomTreeNodes[I] = 0;
}
Vertex.push_back(0);
// 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 = Roots.size(); i != e; ++i)
N = DFSPass(Roots[i], N);
for (unsigned i = N; i >= 2; --i) {
BasicBlock *W = Vertex[i];
InfoRec &WInfo = 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 (Info.count(*SI)) { // Only if this predecessor is reachable!
unsigned SemiU = Info[Eval(*SI)].Semi;
if (SemiU < WInfo.Semi)
WInfo.Semi = SemiU;
}
Info[Vertex[WInfo.Semi]].Bucket.push_back(W);
BasicBlock *WParent = WInfo.Parent;
Link(WParent, W, WInfo);
// Step #3: Implicitly define the immediate dominator of vertices
std::vector<BasicBlock*> &WParentBucket = Info[WParent].Bucket;
while (!WParentBucket.empty()) {
BasicBlock *V = WParentBucket.back();
WParentBucket.pop_back();
BasicBlock *U = Eval(V);
IDoms[V] = Info[U].Semi < Info[V].Semi ? U : WParent;
}
}
// Step #4: Explicitly define the immediate dominator of each vertex
for (unsigned i = 2; i <= N; ++i) {
BasicBlock *W = Vertex[i];
BasicBlock *&WIDom = IDoms[W];
if (WIDom != Vertex[Info[W].Semi])
WIDom = IDoms[WIDom];
}
if (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 = Roots.size() == 1 ? Roots[0] : 0;
DomTreeNodes[Root] = 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 = getIDom(I)) { // Reachable block.
DomTreeNode *&BBNode = DomTreeNodes[I];
if (!BBNode) { // Haven't calculated this node yet?
// Get or calculate the node for the immediate dominator
DomTreeNode *IPDomNode = getNodeForBlock(ImmPostDom);
// Add a new tree node for this BasicBlock, and link it as a child of
// IDomNode
DomTreeNode *C = new DomTreeNode(I, IPDomNode);
DomTreeNodes[I] = C;
BBNode = IPDomNode->addChild(C);
}
}
// Free temporary memory used to construct idom's
IDoms.clear();
Info.clear();
std::vector<BasicBlock*>().swap(Vertex);
// Start out with the DFS numbers being invalid. Let them be computed if
// demanded.
DFSInfoValid = false;
}
DomTreeNode *PostDominatorTree::getNodeForBlock(BasicBlock *BB) {
DomTreeNode *&BBNode = DomTreeNodes[BB];
if (BBNode) return BBNode;
// Haven't calculated this node yet? Get or calculate the node for the
// immediate postdominator.
BasicBlock *IPDom = getIDom(BB);
DomTreeNode *IPDomNode = getNodeForBlock(IPDom);
// Add a new tree node for this BasicBlock, and link it as a child of
// IDomNode
DomTreeNode *C = new DomTreeNode(BB, IPDomNode);
return DomTreeNodes[BB] = IPDomNode->addChild(C);
}
//===----------------------------------------------------------------------===//
// PostDominanceFrontier Implementation
//===----------------------------------------------------------------------===//