mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-11-01 00:11:00 +00:00
455889aa79
llvm/Support/CFG.h * Make pred & succ iterators for intervals global functions * Add #includes that are now neccesary because BasicBlock.h doesn't include InstrTypes.h anymore git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@1750 91177308-0d34-0410-b5e6-96231b3b80d8
397 lines
15 KiB
C++
397 lines
15 KiB
C++
//===- DominatorSet.cpp - Dominator Set Calculation --------------*- C++ -*--=//
|
|
//
|
|
// This file provides a simple class to calculate the dominator set of a method.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include "llvm/Analysis/Dominators.h"
|
|
#include "llvm/Transforms/UnifyMethodExitNodes.h"
|
|
#include "llvm/Method.h"
|
|
#include "llvm/Support/CFG.h"
|
|
#include "Support/DepthFirstIterator.h"
|
|
#include "Support/STLExtras.h"
|
|
#include "Support/SetOperations.h"
|
|
#include <algorithm>
|
|
using std::set;
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// DominatorSet Implementation
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
AnalysisID cfg::DominatorSet::ID(AnalysisID::create<cfg::DominatorSet>());
|
|
AnalysisID cfg::DominatorSet::PostDomID(AnalysisID::create<cfg::DominatorSet>());
|
|
|
|
bool cfg::DominatorSet::runOnMethod(Method *M) {
|
|
Doms.clear(); // Reset from the last time we were run...
|
|
|
|
if (isPostDominator())
|
|
calcPostDominatorSet(M);
|
|
else
|
|
calcForwardDominatorSet(M);
|
|
return false;
|
|
}
|
|
|
|
|
|
// calcForwardDominatorSet - This method calculates the forward dominator sets
|
|
// for the specified method.
|
|
//
|
|
void cfg::DominatorSet::calcForwardDominatorSet(Method *M) {
|
|
Root = M->getEntryNode();
|
|
assert(pred_begin(Root) == pred_end(Root) &&
|
|
"Root node has predecessors in method!");
|
|
|
|
bool Changed;
|
|
do {
|
|
Changed = false;
|
|
|
|
DomSetType WorkingSet;
|
|
df_iterator<Method*> It = df_begin(M), End = df_end(M);
|
|
for ( ; It != End; ++It) {
|
|
const BasicBlock *BB = *It;
|
|
pred_const_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);
|
|
}
|
|
|
|
// Postdominator set constructor. This ctor converts the specified method to
|
|
// only have a single exit node (return stmt), then calculates the post
|
|
// dominance sets for the method.
|
|
//
|
|
void cfg::DominatorSet::calcPostDominatorSet(Method *M) {
|
|
// 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 method left.
|
|
// Get it.
|
|
//
|
|
Root = getAnalysis<UnifyMethodExitNodes>().getExitNode();
|
|
|
|
if (Root == 0) { // No exit node for the method? Postdomsets are all empty
|
|
for (Method::const_iterator MI = M->begin(), ME = M->end(); MI != ME; ++MI)
|
|
Doms[*MI] = DomSetType();
|
|
return;
|
|
}
|
|
|
|
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) {
|
|
const BasicBlock *BB = *It;
|
|
succ_const_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);
|
|
}
|
|
|
|
// getAnalysisUsageInfo - This obviously provides a dominator set, but it also
|
|
// uses the UnifyMethodExitNodes pass if building post-dominators
|
|
//
|
|
void cfg::DominatorSet::getAnalysisUsageInfo(Pass::AnalysisSet &Requires,
|
|
Pass::AnalysisSet &Destroyed,
|
|
Pass::AnalysisSet &Provided) {
|
|
if (isPostDominator()) {
|
|
Provided.push_back(PostDomID);
|
|
Requires.push_back(UnifyMethodExitNodes::ID);
|
|
} else {
|
|
Provided.push_back(ID);
|
|
}
|
|
}
|
|
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// ImmediateDominators Implementation
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
AnalysisID cfg::ImmediateDominators::ID(AnalysisID::create<cfg::ImmediateDominators>());
|
|
AnalysisID cfg::ImmediateDominators::PostDomID(AnalysisID::create<cfg::ImmediateDominators>());
|
|
|
|
// calcIDoms - Calculate the immediate dominator mapping, given a set of
|
|
// dominators for every basic block.
|
|
void cfg::ImmediateDominators::calcIDoms(const DominatorSet &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) {
|
|
const 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;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// DominatorTree Implementation
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
AnalysisID cfg::DominatorTree::ID(AnalysisID::create<cfg::DominatorTree>());
|
|
AnalysisID cfg::DominatorTree::PostDomID(AnalysisID::create<cfg::DominatorTree>());
|
|
|
|
// DominatorTree::reset - Free all of the tree node memory.
|
|
//
|
|
void cfg::DominatorTree::reset() {
|
|
for (NodeMapType::iterator I = Nodes.begin(), E = Nodes.end(); I != E; ++I)
|
|
delete I->second;
|
|
Nodes.clear();
|
|
}
|
|
|
|
|
|
#if 0
|
|
// Given immediate dominators, we can also calculate the dominator tree
|
|
cfg::DominatorTree::DominatorTree(const ImmediateDominators &IDoms)
|
|
: DominatorBase(IDoms.getRoot()) {
|
|
const Method *M = Root->getParent();
|
|
|
|
Nodes[Root] = new Node(Root, 0); // Add a node for the root...
|
|
|
|
// Iterate over all nodes in depth first order...
|
|
for (df_iterator<const Method*> I = df_begin(M), E = df_end(M); I != E; ++I) {
|
|
const BasicBlock *BB = *I, *IDom = IDoms[*I];
|
|
|
|
if (IDom != 0) { // Ignore the root node and other nasty nodes
|
|
// We know that the immediate dominator should already have a node,
|
|
// because we are traversing the CFG in depth first order!
|
|
//
|
|
assert(Nodes[IDom] && "No node for IDOM?");
|
|
Node *IDomNode = Nodes[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));
|
|
}
|
|
}
|
|
}
|
|
#endif
|
|
|
|
void cfg::DominatorTree::calculate(const DominatorSet &DS) {
|
|
Nodes[Root] = new Node(Root, 0); // Add a node for the root...
|
|
|
|
if (!isPostDominator()) {
|
|
// Iterate over all nodes in depth first order...
|
|
for (df_iterator<BasicBlock*> I = df_begin(Root), E = df_end(Root);
|
|
I != E; ++I) {
|
|
const 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
|
|
// method.
|
|
//
|
|
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;
|
|
}
|
|
}
|
|
}
|
|
} else 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) {
|
|
const 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 method.
|
|
//
|
|
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;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// DominanceFrontier Implementation
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
AnalysisID cfg::DominanceFrontier::ID(AnalysisID::create<cfg::DominanceFrontier>());
|
|
AnalysisID cfg::DominanceFrontier::PostDomID(AnalysisID::create<cfg::DominanceFrontier>());
|
|
|
|
const cfg::DominanceFrontier::DomSetType &
|
|
cfg::DominanceFrontier::calcDomFrontier(const DominatorTree &DT,
|
|
const DominatorTree::Node *Node) {
|
|
// Loop over CFG successors to calculate DFlocal[Node]
|
|
const BasicBlock *BB = Node->getNode();
|
|
DomSetType &S = Frontiers[BB]; // The new set to fill in...
|
|
|
|
for (succ_const_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 = calcDomFrontier(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 cfg::DominanceFrontier::DomSetType &
|
|
cfg::DominanceFrontier::calcPostDomFrontier(const DominatorTree &DT,
|
|
const DominatorTree::Node *Node) {
|
|
// Loop over CFG successors to calculate DFlocal[Node]
|
|
const BasicBlock *BB = Node->getNode();
|
|
DomSetType &S = Frontiers[BB]; // The new set to fill in...
|
|
if (!Root) return S;
|
|
|
|
for (pred_const_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 (DominatorTree::Node::const_iterator NI = Node->begin(), NE = Node->end();
|
|
NI != NE; ++NI) {
|
|
DominatorTree::Node *IDominee = *NI;
|
|
const DomSetType &ChildDF = calcPostDomFrontier(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;
|
|
}
|