mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-12-28 19:31:58 +00:00
eb702350f7
provide themselves. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@3124 91177308-0d34-0410-b5e6-96231b3b80d8
450 lines
17 KiB
C++
450 lines
17 KiB
C++
//===- DominatorSet.cpp - Dominator Set Calculation --------------*- C++ -*--=//
|
|
//
|
|
// This file provides a simple class to calculate the dominator set of a
|
|
// function.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include "llvm/Analysis/Dominators.h"
|
|
#include "llvm/Transforms/Utils/UnifyFunctionExitNodes.h"
|
|
#include "llvm/Support/CFG.h"
|
|
#include "llvm/Assembly/Writer.h"
|
|
#include "Support/DepthFirstIterator.h"
|
|
#include "Support/STLExtras.h"
|
|
#include "Support/SetOperations.h"
|
|
#include <algorithm>
|
|
using std::set;
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// DominatorSet Implementation
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
static RegisterAnalysis<DominatorSet>
|
|
A("domset", "Dominator Set Construction");
|
|
static RegisterAnalysis<PostDominatorSet>
|
|
B("postdomset", "Post-Dominator Set Construction");
|
|
|
|
AnalysisID DominatorSet::ID = A;
|
|
AnalysisID PostDominatorSet::ID = B;
|
|
|
|
// dominates - Return true if A dominates B. This performs the special checks
|
|
// neccesary if A and B are in the same basic block.
|
|
//
|
|
bool DominatorSetBase::dominates(Instruction *A, Instruction *B) const {
|
|
BasicBlock *BBA = A->getParent(), *BBB = B->getParent();
|
|
if (BBA != BBB) return dominates(BBA, BBB);
|
|
|
|
// Loop through the basic block until we find A or B.
|
|
BasicBlock::iterator I = BBA->begin();
|
|
for (; &*I != A && &*I != B; ++I) /*empty*/;
|
|
|
|
// A dominates B if it is found first in the basic block...
|
|
return &*I == A;
|
|
}
|
|
|
|
// runOnFunction - This method calculates the forward dominator sets for the
|
|
// specified function.
|
|
//
|
|
bool DominatorSet::runOnFunction(Function &F) {
|
|
Doms.clear(); // Reset from the last time we were run...
|
|
Root = &F.getEntryNode();
|
|
assert(pred_begin(Root) == pred_end(Root) &&
|
|
"Root node has predecessors in function!");
|
|
|
|
bool Changed;
|
|
do {
|
|
Changed = false;
|
|
|
|
DomSetType WorkingSet;
|
|
df_iterator<Function*> It = df_begin(&F), End = df_end(&F);
|
|
for ( ; It != End; ++It) {
|
|
BasicBlock *BB = *It;
|
|
pred_iterator PI = pred_begin(BB), PEnd = pred_end(BB);
|
|
if (PI != PEnd) { // Is there SOME predecessor?
|
|
// Loop until we get to a predecessor that has had it's dom set filled
|
|
// in at least once. We are guaranteed to have this because we are
|
|
// traversing the graph in DFO and have handled start nodes specially.
|
|
//
|
|
while (Doms[*PI].size() == 0) ++PI;
|
|
WorkingSet = Doms[*PI];
|
|
|
|
for (++PI; PI != PEnd; ++PI) { // Intersect all of the predecessor sets
|
|
DomSetType &PredSet = Doms[*PI];
|
|
if (PredSet.size())
|
|
set_intersect(WorkingSet, PredSet);
|
|
}
|
|
}
|
|
|
|
WorkingSet.insert(BB); // A block always dominates itself
|
|
DomSetType &BBSet = Doms[BB];
|
|
if (BBSet != WorkingSet) {
|
|
BBSet.swap(WorkingSet); // Constant time operation!
|
|
Changed = true; // The sets changed.
|
|
}
|
|
WorkingSet.clear(); // Clear out the set for next iteration
|
|
}
|
|
} while (Changed);
|
|
return false;
|
|
}
|
|
|
|
|
|
// Postdominator set construction. This converts the specified function to only
|
|
// have a single exit node (return stmt), then calculates the post dominance
|
|
// sets for the function.
|
|
//
|
|
bool PostDominatorSet::runOnFunction(Function &F) {
|
|
Doms.clear(); // Reset from the last time we were run...
|
|
// Since we require that the unify all exit nodes pass has been run, we know
|
|
// that there can be at most one return instruction in the function left.
|
|
// Get it.
|
|
//
|
|
Root = getAnalysis<UnifyFunctionExitNodes>().getExitNode();
|
|
|
|
if (Root == 0) { // No exit node for the function? Postdomsets are all empty
|
|
for (Function::iterator FI = F.begin(), FE = F.end(); FI != FE; ++FI)
|
|
Doms[FI] = DomSetType();
|
|
return false;
|
|
}
|
|
|
|
bool Changed;
|
|
do {
|
|
Changed = false;
|
|
|
|
set<const BasicBlock*> Visited;
|
|
DomSetType WorkingSet;
|
|
idf_iterator<BasicBlock*> It = idf_begin(Root), End = idf_end(Root);
|
|
for ( ; It != End; ++It) {
|
|
BasicBlock *BB = *It;
|
|
succ_iterator PI = succ_begin(BB), PEnd = succ_end(BB);
|
|
if (PI != PEnd) { // Is there SOME predecessor?
|
|
// Loop until we get to a successor that has had it's dom set filled
|
|
// in at least once. We are guaranteed to have this because we are
|
|
// traversing the graph in DFO and have handled start nodes specially.
|
|
//
|
|
while (Doms[*PI].size() == 0) ++PI;
|
|
WorkingSet = Doms[*PI];
|
|
|
|
for (++PI; PI != PEnd; ++PI) { // Intersect all of the successor sets
|
|
DomSetType &PredSet = Doms[*PI];
|
|
if (PredSet.size())
|
|
set_intersect(WorkingSet, PredSet);
|
|
}
|
|
}
|
|
|
|
WorkingSet.insert(BB); // A block always dominates itself
|
|
DomSetType &BBSet = Doms[BB];
|
|
if (BBSet != WorkingSet) {
|
|
BBSet.swap(WorkingSet); // Constant time operation!
|
|
Changed = true; // The sets changed.
|
|
}
|
|
WorkingSet.clear(); // Clear out the set for next iteration
|
|
}
|
|
} while (Changed);
|
|
return false;
|
|
}
|
|
|
|
// getAnalysisUsage - This obviously provides a post-dominator set, but it also
|
|
// requires the UnifyFunctionExitNodes pass.
|
|
//
|
|
void PostDominatorSet::getAnalysisUsage(AnalysisUsage &AU) const {
|
|
AU.setPreservesAll();
|
|
AU.addRequired(UnifyFunctionExitNodes::ID);
|
|
}
|
|
|
|
static ostream &operator<<(ostream &o, const set<BasicBlock*> &BBs) {
|
|
for (set<BasicBlock*>::const_iterator I = BBs.begin(), E = BBs.end();
|
|
I != E; ++I) {
|
|
o << " ";
|
|
WriteAsOperand(o, *I, false);
|
|
o << "\n";
|
|
}
|
|
return o;
|
|
}
|
|
|
|
void DominatorSetBase::print(std::ostream &o) const {
|
|
for (const_iterator I = begin(), E = end(); I != E; ++I)
|
|
o << "=============================--------------------------------\n"
|
|
<< "\nDominator Set For Basic Block\n" << I->first
|
|
<< "-------------------------------\n" << I->second << "\n";
|
|
}
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// ImmediateDominators Implementation
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
static RegisterAnalysis<ImmediateDominators>
|
|
C("idom", "Immediate Dominators Construction");
|
|
static RegisterAnalysis<ImmediatePostDominators>
|
|
D("postidom", "Immediate Post-Dominators Construction");
|
|
|
|
AnalysisID ImmediateDominators::ID = C;
|
|
AnalysisID ImmediatePostDominators::ID = D;
|
|
|
|
// calcIDoms - Calculate the immediate dominator mapping, given a set of
|
|
// dominators for every basic block.
|
|
void ImmediateDominatorsBase::calcIDoms(const DominatorSetBase &DS) {
|
|
// Loop over all of the nodes that have dominators... figuring out the IDOM
|
|
// for each node...
|
|
//
|
|
for (DominatorSet::const_iterator DI = DS.begin(), DEnd = DS.end();
|
|
DI != DEnd; ++DI) {
|
|
BasicBlock *BB = DI->first;
|
|
const DominatorSet::DomSetType &Dominators = DI->second;
|
|
unsigned DomSetSize = Dominators.size();
|
|
if (DomSetSize == 1) continue; // Root node... IDom = null
|
|
|
|
// Loop over all dominators of this node. This corresponds to looping over
|
|
// nodes in the dominator chain, looking for a node whose dominator set is
|
|
// equal to the current nodes, except that the current node does not exist
|
|
// in it. This means that it is one level higher in the dom chain than the
|
|
// current node, and it is our idom!
|
|
//
|
|
DominatorSet::DomSetType::const_iterator I = Dominators.begin();
|
|
DominatorSet::DomSetType::const_iterator End = Dominators.end();
|
|
for (; I != End; ++I) { // Iterate over dominators...
|
|
// All of our dominators should form a chain, where the number of elements
|
|
// in the dominator set indicates what level the node is at in the chain.
|
|
// We want the node immediately above us, so it will have an identical
|
|
// dominator set, except that BB will not dominate it... therefore it's
|
|
// dominator set size will be one less than BB's...
|
|
//
|
|
if (DS.getDominators(*I).size() == DomSetSize - 1) {
|
|
IDoms[BB] = *I;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void ImmediateDominatorsBase::print(ostream &o) const {
|
|
for (const_iterator I = begin(), E = end(); I != E; ++I)
|
|
o << "=============================--------------------------------\n"
|
|
<< "\nImmediate Dominator For Basic Block\n" << *I->first
|
|
<< "is: \n" << *I->second << "\n";
|
|
}
|
|
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// DominatorTree Implementation
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
static RegisterAnalysis<DominatorTree>
|
|
E("domtree", "Dominator Tree Construction");
|
|
static RegisterAnalysis<PostDominatorTree>
|
|
F("postdomtree", "Post-Dominator Tree Construction");
|
|
|
|
AnalysisID DominatorTree::ID = E;
|
|
AnalysisID PostDominatorTree::ID = F;
|
|
|
|
// DominatorTreeBase::reset - Free all of the tree node memory.
|
|
//
|
|
void DominatorTreeBase::reset() {
|
|
for (NodeMapType::iterator I = Nodes.begin(), E = Nodes.end(); I != E; ++I)
|
|
delete I->second;
|
|
Nodes.clear();
|
|
}
|
|
|
|
|
|
void DominatorTree::calculate(const DominatorSet &DS) {
|
|
Nodes[Root] = new Node(Root, 0); // Add a node for the root...
|
|
|
|
// Iterate over all nodes in depth first order...
|
|
for (df_iterator<BasicBlock*> I = df_begin(Root), E = df_end(Root);
|
|
I != E; ++I) {
|
|
BasicBlock *BB = *I;
|
|
const DominatorSet::DomSetType &Dominators = DS.getDominators(BB);
|
|
unsigned DomSetSize = Dominators.size();
|
|
if (DomSetSize == 1) continue; // Root node... IDom = null
|
|
|
|
// Loop over all dominators of this node. This corresponds to looping over
|
|
// nodes in the dominator chain, looking for a node whose dominator set is
|
|
// equal to the current nodes, except that the current node does not exist
|
|
// in it. This means that it is one level higher in the dom chain than the
|
|
// current node, and it is our idom! We know that we have already added
|
|
// a DominatorTree node for our idom, because the idom must be a
|
|
// predecessor in the depth first order that we are iterating through the
|
|
// function.
|
|
//
|
|
DominatorSet::DomSetType::const_iterator I = Dominators.begin();
|
|
DominatorSet::DomSetType::const_iterator End = Dominators.end();
|
|
for (; I != End; ++I) { // Iterate over dominators...
|
|
// All of our dominators should form a chain, where the number of
|
|
// elements in the dominator set indicates what level the node is at in
|
|
// the chain. We want the node immediately above us, so it will have
|
|
// an identical dominator set, except that BB will not dominate it...
|
|
// therefore it's dominator set size will be one less than BB's...
|
|
//
|
|
if (DS.getDominators(*I).size() == DomSetSize - 1) {
|
|
// We know that the immediate dominator should already have a node,
|
|
// because we are traversing the CFG in depth first order!
|
|
//
|
|
Node *IDomNode = Nodes[*I];
|
|
assert(IDomNode && "No node for IDOM?");
|
|
|
|
// Add a new tree node for this BasicBlock, and link it as a child of
|
|
// IDomNode
|
|
Nodes[BB] = IDomNode->addChild(new Node(BB, IDomNode));
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
void PostDominatorTree::calculate(const PostDominatorSet &DS) {
|
|
Nodes[Root] = new Node(Root, 0); // Add a node for the root...
|
|
|
|
if (Root) {
|
|
// Iterate over all nodes in depth first order...
|
|
for (idf_iterator<BasicBlock*> I = idf_begin(Root), E = idf_end(Root);
|
|
I != E; ++I) {
|
|
BasicBlock *BB = *I;
|
|
const DominatorSet::DomSetType &Dominators = DS.getDominators(BB);
|
|
unsigned DomSetSize = Dominators.size();
|
|
if (DomSetSize == 1) continue; // Root node... IDom = null
|
|
|
|
// Loop over all dominators of this node. This corresponds to looping
|
|
// over nodes in the dominator chain, looking for a node whose dominator
|
|
// set is equal to the current nodes, except that the current node does
|
|
// not exist in it. This means that it is one level higher in the dom
|
|
// chain than the current node, and it is our idom! We know that we have
|
|
// already added a DominatorTree node for our idom, because the idom must
|
|
// be a predecessor in the depth first order that we are iterating through
|
|
// the function.
|
|
//
|
|
DominatorSet::DomSetType::const_iterator I = Dominators.begin();
|
|
DominatorSet::DomSetType::const_iterator End = Dominators.end();
|
|
for (; I != End; ++I) { // Iterate over dominators...
|
|
// All of our dominators should form a chain, where the number
|
|
// of elements in the dominator set indicates what level the
|
|
// node is at in the chain. We want the node immediately
|
|
// above us, so it will have an identical dominator set,
|
|
// except that BB will not dominate it... therefore it's
|
|
// dominator set size will be one less than BB's...
|
|
//
|
|
if (DS.getDominators(*I).size() == DomSetSize - 1) {
|
|
// We know that the immediate dominator should already have a node,
|
|
// because we are traversing the CFG in depth first order!
|
|
//
|
|
Node *IDomNode = Nodes[*I];
|
|
assert(IDomNode && "No node for IDOM?");
|
|
|
|
// Add a new tree node for this BasicBlock, and link it as a child of
|
|
// IDomNode
|
|
Nodes[BB] = IDomNode->addChild(new Node(BB, IDomNode));
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
static ostream &operator<<(ostream &o, const DominatorTreeBase::Node *Node) {
|
|
return o << Node->getNode()
|
|
<< "\n------------------------------------------\n";
|
|
}
|
|
|
|
static void PrintDomTree(const DominatorTreeBase::Node *N, ostream &o,
|
|
unsigned Lev) {
|
|
o << "Level #" << Lev << ": " << N;
|
|
for (DominatorTreeBase::Node::const_iterator I = N->begin(), E = N->end();
|
|
I != E; ++I) {
|
|
PrintDomTree(*I, o, Lev+1);
|
|
}
|
|
}
|
|
|
|
void DominatorTreeBase::print(std::ostream &o) const {
|
|
o << "=============================--------------------------------\n"
|
|
<< "Inorder Dominator Tree:\n";
|
|
PrintDomTree(Nodes.find(getRoot())->second, o, 1);
|
|
}
|
|
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// DominanceFrontier Implementation
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
static RegisterAnalysis<DominanceFrontier>
|
|
G("domfrontier", "Dominance Frontier Construction");
|
|
static RegisterAnalysis<PostDominanceFrontier>
|
|
H("postdomfrontier", "Post-Dominance Frontier Construction");
|
|
|
|
AnalysisID DominanceFrontier::ID = G;
|
|
AnalysisID PostDominanceFrontier::ID = H;
|
|
|
|
const DominanceFrontier::DomSetType &
|
|
DominanceFrontier::calculate(const DominatorTree &DT,
|
|
const DominatorTree::Node *Node) {
|
|
// Loop over CFG successors to calculate DFlocal[Node]
|
|
BasicBlock *BB = Node->getNode();
|
|
DomSetType &S = Frontiers[BB]; // The new set to fill in...
|
|
|
|
for (succ_iterator SI = succ_begin(BB), SE = succ_end(BB);
|
|
SI != SE; ++SI) {
|
|
// Does Node immediately dominate this successor?
|
|
if (DT[*SI]->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 (DominatorTree::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->dominates(DT[*CDFI]))
|
|
S.insert(*CDFI);
|
|
}
|
|
}
|
|
|
|
return S;
|
|
}
|
|
|
|
const DominanceFrontier::DomSetType &
|
|
PostDominanceFrontier::calculate(const PostDominatorTree &DT,
|
|
const DominatorTree::Node *Node) {
|
|
// Loop over CFG successors to calculate DFlocal[Node]
|
|
BasicBlock *BB = Node->getNode();
|
|
DomSetType &S = Frontiers[BB]; // The new set to fill in...
|
|
if (!Root) return S;
|
|
|
|
for (pred_iterator SI = pred_begin(BB), SE = pred_end(BB);
|
|
SI != SE; ++SI) {
|
|
// Does Node immediately dominate this predeccessor?
|
|
if (DT[*SI]->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->dominates(DT[*CDFI]))
|
|
S.insert(*CDFI);
|
|
}
|
|
}
|
|
|
|
return S;
|
|
}
|
|
|
|
void DominanceFrontierBase::print(std::ostream &o) const {
|
|
for (const_iterator I = begin(), E = end(); I != E; ++I) {
|
|
o << "=============================--------------------------------\n"
|
|
<< "\nDominance Frontier For Basic Block\n";
|
|
WriteAsOperand(o, I->first, false);
|
|
o << " is: \n" << I->second << "\n";
|
|
}
|
|
}
|