mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-12-15 20:29:48 +00:00
5a713cc72f
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@36239 91177308-0d34-0410-b5e6-96231b3b80d8
313 lines
10 KiB
C++
313 lines
10 KiB
C++
//===- PostDominators.cpp - Post-Dominator Calculation --------------------===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file was developed by the LLVM research group and is distributed under
|
|
// the University of Illinois Open Source License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// This file implements the post-dominator construction algorithms.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include "llvm/Analysis/PostDominators.h"
|
|
#include "llvm/Instructions.h"
|
|
#include "llvm/Support/CFG.h"
|
|
#include "llvm/ADT/DepthFirstIterator.h"
|
|
#include "llvm/ADT/SetOperations.h"
|
|
using namespace llvm;
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// PostDominatorTree Implementation
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
static RegisterPass<PostDominatorTree>
|
|
F("postdomtree", "Post-Dominator Tree Construction", true);
|
|
|
|
unsigned PostDominatorTree::DFSPass(BasicBlock *V, InfoRec &VInfo,
|
|
unsigned N) {
|
|
std::vector<std::pair<BasicBlock *, InfoRec *> > workStack;
|
|
std::set<BasicBlock *> visited;
|
|
workStack.push_back(std::make_pair(V, &VInfo));
|
|
|
|
do {
|
|
BasicBlock *currentBB = workStack.back().first;
|
|
InfoRec *currentVInfo = workStack.back().second;
|
|
|
|
// Visit each block only once.
|
|
if (visited.count(currentBB) == 0) {
|
|
|
|
visited.insert(currentBB);
|
|
currentVInfo->Semi = ++N;
|
|
currentVInfo->Label = currentBB;
|
|
|
|
Vertex.push_back(currentBB); // Vertex[n] = current;
|
|
// Info[currentBB].Ancestor = 0;
|
|
// Ancestor[n] = 0
|
|
// Child[currentBB] = 0;
|
|
currentVInfo->Size = 1; // Size[currentBB] = 1
|
|
}
|
|
|
|
// Visit children
|
|
bool visitChild = false;
|
|
for (pred_iterator PI = pred_begin(currentBB), PE = pred_end(currentBB);
|
|
PI != PE && !visitChild; ++PI) {
|
|
InfoRec &SuccVInfo = Info[*PI];
|
|
if (SuccVInfo.Semi == 0) {
|
|
SuccVInfo.Parent = currentBB;
|
|
if (visited.count (*PI) == 0) {
|
|
workStack.push_back(std::make_pair(*PI, &SuccVInfo));
|
|
visitChild = true;
|
|
}
|
|
}
|
|
}
|
|
|
|
// If all children are visited or if this block has no child then pop this
|
|
// block out of workStack.
|
|
if (!visitChild)
|
|
workStack.pop_back();
|
|
|
|
} while (!workStack.empty());
|
|
|
|
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)
|
|
if (succ_begin(I) == succ_end(I))
|
|
Roots.push_back(I);
|
|
|
|
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], Info[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;
|
|
Nodes[Root] = RootNode = new Node(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.
|
|
Node *&BBNode = Nodes[I];
|
|
if (!BBNode) { // Haven't calculated this node yet?
|
|
// Get or calculate the node for the immediate dominator
|
|
Node *IPDomNode = getNodeForBlock(ImmPostDom);
|
|
|
|
// Add a new tree node for this BasicBlock, and link it as a child of
|
|
// IDomNode
|
|
BBNode = IPDomNode->addChild(new Node(I, IPDomNode));
|
|
}
|
|
}
|
|
|
|
// Free temporary memory used to construct idom's
|
|
IDoms.clear();
|
|
Info.clear();
|
|
std::vector<BasicBlock*>().swap(Vertex);
|
|
}
|
|
|
|
|
|
DominatorTreeBase::Node *PostDominatorTree::getNodeForBlock(BasicBlock *BB) {
|
|
Node *&BBNode = Nodes[BB];
|
|
if (BBNode) return BBNode;
|
|
|
|
// Haven't calculated this node yet? Get or calculate the node for the
|
|
// immediate postdominator.
|
|
BasicBlock *IPDom = getIDom(BB);
|
|
Node *IPDomNode = getNodeForBlock(IPDom);
|
|
|
|
// Add a new tree node for this BasicBlock, and link it as a child of
|
|
// IDomNode
|
|
return BBNode = IPDomNode->addChild(new Node(BB, IPDomNode));
|
|
}
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// PostETForest Implementation
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
static RegisterPass<PostETForest>
|
|
G("postetforest", "Post-ET-Forest Construction", true);
|
|
|
|
ETNode *PostETForest::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.
|
|
PostDominatorTree::Node *node = getAnalysis<PostDominatorTree>().getNode(BB);
|
|
|
|
// If we are unreachable, we may not have an immediate dominator.
|
|
if (!node)
|
|
return 0;
|
|
else if (!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 PostETForest::calculate(const PostDominatorTree &DT) {
|
|
for (unsigned i = 0, e = Roots.size(); i != e; ++i)
|
|
Nodes[Roots[i]] = new ETNode(Roots[i]); // Add a node for the root
|
|
|
|
// Iterate over all nodes in inverse depth first order.
|
|
for (unsigned i = 0, e = Roots.size(); i != e; ++i)
|
|
for (idf_iterator<BasicBlock*> I = idf_begin(Roots[i]),
|
|
E = idf_end(Roots[i]); I != E; ++I) {
|
|
BasicBlock *BB = *I;
|
|
ETNode *&BBNode = Nodes[BB];
|
|
if (!BBNode) {
|
|
ETNode *IDomNode = NULL;
|
|
PostDominatorTree::Node *node = DT.getNode(BB);
|
|
if (node && node->getIDom())
|
|
IDomNode = getNodeForBlock(node->getIDom()->getBlock());
|
|
|
|
// Add a new ETNode for this BasicBlock, and set it's parent
|
|
// to it's immediate dominator.
|
|
BBNode = new ETNode(BB);
|
|
if (IDomNode)
|
|
BBNode->setFather(IDomNode);
|
|
}
|
|
}
|
|
|
|
int dfsnum = 0;
|
|
// Iterate over all nodes in depth first order...
|
|
for (unsigned i = 0, e = Roots.size(); i != e; ++i)
|
|
for (idf_iterator<BasicBlock*> I = idf_begin(Roots[i]),
|
|
E = idf_end(Roots[i]); I != E; ++I) {
|
|
if (!getNodeForBlock(*I)->hasFather())
|
|
getNodeForBlock(*I)->assignDFSNumber(dfsnum);
|
|
}
|
|
DFSInfoValid = true;
|
|
}
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// PostDominanceFrontier Implementation
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
static RegisterPass<PostDominanceFrontier>
|
|
H("postdomfrontier", "Post-Dominance Frontier Construction", true);
|
|
|
|
const DominanceFrontier::DomSetType &
|
|
PostDominanceFrontier::calculate(const PostDominatorTree &DT,
|
|
const DominatorTree::Node *Node) {
|
|
// Loop over CFG successors to calculate DFlocal[Node]
|
|
BasicBlock *BB = Node->getBlock();
|
|
DomSetType &S = Frontiers[BB]; // The new set to fill in...
|
|
if (getRoots().empty()) return S;
|
|
|
|
if (BB)
|
|
for (pred_iterator SI = pred_begin(BB), SE = pred_end(BB);
|
|
SI != SE; ++SI) {
|
|
// Does Node immediately dominate this predecessor?
|
|
DominatorTree::Node *SINode = DT[*SI];
|
|
if (SINode && SINode->getIDom() != Node)
|
|
S.insert(*SI);
|
|
}
|
|
|
|
// At this point, S is DFlocal. Now we union in DFup's of our children...
|
|
// Loop through and visit the nodes that Node immediately dominates (Node's
|
|
// children in the IDomTree)
|
|
//
|
|
for (PostDominatorTree::Node::const_iterator
|
|
NI = Node->begin(), NE = Node->end(); NI != NE; ++NI) {
|
|
DominatorTree::Node *IDominee = *NI;
|
|
const DomSetType &ChildDF = calculate(DT, IDominee);
|
|
|
|
DomSetType::const_iterator CDFI = ChildDF.begin(), CDFE = ChildDF.end();
|
|
for (; CDFI != CDFE; ++CDFI) {
|
|
if (!Node->properlyDominates(DT[*CDFI]))
|
|
S.insert(*CDFI);
|
|
}
|
|
}
|
|
|
|
return S;
|
|
}
|
|
|
|
// Ensure that this .cpp file gets linked when PostDominators.h is used.
|
|
DEFINING_FILE_FOR(PostDominanceFrontier)
|