Complete rewrite of BU code to use Tarjan's SCC finding algorithm to drive

the algorithm instead of hand coded depth first iteration


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@4694 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2002-11-11 21:35:13 +00:00
parent cf69bb494a
commit a9c9c0216e

View File

@ -18,19 +18,230 @@ X("budatastructure", "Bottom-up Data Structure Analysis Closure");
using namespace DS;
// isCompleteNode - Return true if we know all of the targets of this node, and
// if the call sites are not external.
//
static inline bool isCompleteNode(DSNode *N) {
if (N->NodeType & DSNode::Incomplete) return false;
const std::vector<GlobalValue*> &Callees = N->getGlobals();
for (unsigned i = 0, e = Callees.size(); i != e; ++i)
if (Callees[i]->isExternal()) {
GlobalValue &FI = cast<Function>(*Callees[i]);
if (FI.getName() != "printf" && FI.getName() != "sscanf" &&
FI.getName() != "fprintf" && FI.getName() != "open" &&
FI.getName() != "sprintf" && FI.getName() != "fputs")
return false; // External function found...
}
return true; // otherwise ok
}
struct CallSiteIterator {
// FCs are the edges out of the current node are the call site targets...
std::vector<DSCallSite> *FCs;
unsigned CallSite;
unsigned CallSiteEntry;
CallSiteIterator(std::vector<DSCallSite> &CS) : FCs(&CS) {
CallSite = 0; CallSiteEntry = 0;
advanceToNextValid();
}
// End iterator ctor...
CallSiteIterator(std::vector<DSCallSite> &CS, bool) : FCs(&CS) {
CallSite = FCs->size(); CallSiteEntry = 0;
}
void advanceToNextValid() {
while (CallSite < FCs->size()) {
if (DSNode *CalleeNode = (*FCs)[CallSite].getCallee().getNode()) {
if (CallSiteEntry || isCompleteNode(CalleeNode)) {
const std::vector<GlobalValue*> &Callees = CalleeNode->getGlobals();
if (CallSiteEntry < Callees.size())
return;
}
CallSiteEntry = 0;
++CallSite;
}
}
}
public:
static CallSiteIterator begin(DSGraph &G) { return G.getAuxFunctionCalls(); }
static CallSiteIterator end(DSGraph &G) {
return CallSiteIterator(G.getAuxFunctionCalls(), true);
}
static CallSiteIterator begin(std::vector<DSCallSite> &CSs) { return CSs; }
static CallSiteIterator end(std::vector<DSCallSite> &CSs) {
return CallSiteIterator(CSs, true);
}
bool operator==(const CallSiteIterator &CSI) const {
return CallSite == CSI.CallSite && CallSiteEntry == CSI.CallSiteEntry;
}
bool operator!=(const CallSiteIterator &CSI) const { return !operator==(CSI);}
unsigned getCallSiteIdx() const { return CallSite; }
DSCallSite &getCallSite() const { return (*FCs)[CallSite]; }
Function* operator*() const {
DSNode *Node = (*FCs)[CallSite].getCallee().getNode();
return cast<Function>(Node->getGlobals()[CallSiteEntry]);
}
CallSiteIterator& operator++() { // Preincrement
++CallSiteEntry;
advanceToNextValid();
return *this;
}
CallSiteIterator operator++(int) { // Postincrement
CallSiteIterator tmp = *this; ++*this; return tmp;
}
};
// run - Calculate the bottom up data structure graphs for each function in the
// program.
//
bool BUDataStructures::run(Module &M) {
GlobalsGraph = new DSGraph();
// Simply calculate the graphs for each function...
Function *MainFunc = M.getMainFunction();
if (MainFunc)
calculateReachableGraphs(MainFunc);
// Calculate the graphs for any functions that are unreachable from main...
for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
if (!I->isExternal())
calculateGraph(*I, 0);
if (!I->isExternal() && DSInfo.find(I) == DSInfo.end()) {
if (MainFunc)
std::cerr << "*** Function unreachable from main: "
<< I->getName() << "\n";
calculateReachableGraphs(I); // Calculate all graphs...
}
return false;
}
void BUDataStructures::calculateReachableGraphs(Function *F) {
std::vector<Function*> Stack;
std::map<Function*, unsigned> ValMap;
unsigned NextID = 1;
calculateGraphs(F, Stack, NextID, ValMap);
}
DSGraph &BUDataStructures::getOrCreateGraph(Function *F) {
// Has the graph already been created?
DSGraph *&Graph = DSInfo[F];
if (Graph) return *Graph;
// Copy the local version into DSInfo...
Graph = new DSGraph(getAnalysis<LocalDataStructures>().getDSGraph(*F));
Graph->setGlobalsGraph(GlobalsGraph);
Graph->setPrintAuxCalls();
// Start with a copy of the original call sites...
Graph->getAuxFunctionCalls() = Graph->getFunctionCalls();
return *Graph;
}
unsigned BUDataStructures::calculateGraphs(Function *F,
std::vector<Function*> &Stack,
unsigned &NextID,
std::map<Function*, unsigned> &ValMap) {
assert(ValMap.find(F) == ValMap.end() && "Shouldn't revisit functions!");
unsigned Min = NextID++, MyID = Min;
ValMap[F] = Min;
Stack.push_back(F);
if (F->isExternal()) { // sprintf, fprintf, sscanf, etc...
// No callees!
Stack.pop_back();
ValMap[F] = ~0;
return Min;
}
DSGraph &Graph = getOrCreateGraph(F);
// The edges out of the current node are the call site targets...
for (CallSiteIterator I = CallSiteIterator::begin(Graph),
E = CallSiteIterator::end(Graph); I != E; ++I) {
Function *Callee = *I;
unsigned M;
// Have we visited the destination function yet?
std::map<Function*, unsigned>::iterator It = ValMap.find(Callee);
if (It == ValMap.end()) // No, visit it now.
M = calculateGraphs(Callee, Stack, NextID, ValMap);
else // Yes, get it's number.
M = It->second;
if (M < Min) Min = M;
}
assert(ValMap[F] == MyID && "SCC construction assumption wrong!");
if (Min != MyID)
return Min; // This is part of a larger SCC!
// If this is a new SCC, process it now.
if (Stack.back() == F) { // Special case the single "SCC" case here.
DEBUG(std::cerr << "Visiting single node SCC #: " << MyID << " fn: "
<< F->getName() << "\n");
Stack.pop_back();
DSGraph &G = calculateGraph(*F);
// Should we revisit the graph?
if (CallSiteIterator::begin(G) != CallSiteIterator::end(G)) {
ValMap.erase(F);
return calculateGraphs(F, Stack, NextID, ValMap);
} else {
ValMap[F] = ~0U;
}
return MyID;
} else {
// SCCFunctions - Keep track of the functions in the current SCC
//
std::set<Function*> SCCFunctions;
Function *NF;
std::vector<Function*>::iterator FirstInSCC = Stack.end();
do {
NF = *--FirstInSCC;
ValMap[NF] = ~0U;
SCCFunctions.insert(NF);
} while (NF != F);
std::cerr << "Identified SCC #: " << MyID << " of size: "
<< (Stack.end()-FirstInSCC) << "\n";
std::vector<Function*>::iterator I = Stack.end();
do {
--I;
/*DEBUG*/(std::cerr << " Fn #" << (Stack.end()-I) << "/"
<< (Stack.end()-FirstInSCC) << " in SCC: "
<< (*I)->getName());
DSGraph &G = getDSGraph(**I);
std::cerr << " [" << G.getGraphSize() << "+"
<< G.getAuxFunctionCalls().size() << "] " << std::flush;
// Inline all graphs into the last (highest numbered) node in the SCC
calculateSCCGraph(**I, SCCFunctions);
std::cerr << "after [" << G.getGraphSize() << "+"
<< G.getAuxFunctionCalls().size() << "]\n";
} while (I != FirstInSCC);
std::cerr << "DONE with SCC #: " << MyID << "\n";
// We never have to revisit "SCC" processed functions...
// Drop the stuff we don't need from the end of the stack
Stack.erase(FirstInSCC, Stack.end());
return MyID;
}
return MyID; // == Min
}
// releaseMemory - If the pass pipeline is done with this pass, we can release
// our memory... here...
//
@ -46,294 +257,169 @@ void BUDataStructures::releaseMemory() {
GlobalsGraph = 0;
}
DSGraph &BUDataStructures::calculateGraph(Function &F) {
DSGraph &Graph = getDSGraph(F);
DEBUG(std::cerr << " [BU] Calculating graph for: " << F.getName() << "\n");
// Return true if a graph was inlined
// Can not modify the part of the AuxCallList < FirstResolvableCall.
//
bool BUDataStructures::ResolveFunctionCalls(DSGraph &G,
unsigned &FirstResolvableCall,
std::map<Function*, DSCallSite> &InProcess,
unsigned Indent) {
std::vector<DSCallSite> &FCs = G.getAuxFunctionCalls();
bool Changed = false;
// Move our call site list into TempFCs so that inline call sites go into the
// new call site list and doesn't invalidate our iterators!
std::vector<DSCallSite> TempFCs;
std::vector<DSCallSite> &AuxCallsList = Graph.getAuxFunctionCalls();
TempFCs.swap(AuxCallsList);
// Loop while there are call sites that we can resolve!
while (FirstResolvableCall != FCs.size()) {
DSCallSite Call = FCs[FirstResolvableCall];
// If the function list is incomplete...
if (Call.getCallee().getNode()->NodeType & DSNode::Incomplete) {
// If incomplete, we cannot resolve it, so leave it at the beginning of
// the call list with the other unresolvable calls...
++FirstResolvableCall;
} else {
// Start inlining all of the functions we can... some may not be
// inlinable if they are external...
//
const std::vector<GlobalValue*> &Callees =
Call.getCallee().getNode()->getGlobals();
bool hasExternalTarget = false;
// Loop over the functions, inlining whatever we can...
for (unsigned c = 0, e = Callees.size(); c != e; ++c) {
// Must be a function type, so this cast should succeed unless something
// really wierd is happening.
Function &FI = cast<Function>(*Callees[c]);
if (FI.getName() == "printf" || FI.getName() == "sscanf" ||
FI.getName() == "fprintf" || FI.getName() == "open" ||
FI.getName() == "sprintf" || FI.getName() == "fputs") {
// Ignore
} else if (FI.isExternal()) {
// If the function is external, then we cannot resolve this call site!
hasExternalTarget = true;
break;
} else {
std::map<Function*, DSCallSite>::iterator I =
InProcess.lower_bound(&FI);
if (I != InProcess.end() && I->first == &FI) { // Recursion detected?
// Merge two call sites to eliminate recursion...
Call.mergeWith(I->second);
DEBUG(std::cerr << std::string(Indent*2, ' ')
<< "* Recursion detected for function " << FI.getName()<<"\n");
} else {
DEBUG(std::cerr << std::string(Indent*2, ' ')
<< "Inlining: " << FI.getName() << "\n");
// Get the data structure graph for the called function, closing it
// if possible...
//
DSGraph &GI = calculateGraph(FI, Indent+1); // Graph to inline
DEBUG(std::cerr << std::string(Indent*2, ' ')
<< "Got graph for: " << FI.getName() << "["
<< GI.getGraphSize() << "+"
<< GI.getAuxFunctionCalls().size() << "] "
<< " in: " << G.getFunction().getName() << "["
<< G.getGraphSize() << "+"
<< G.getAuxFunctionCalls().size() << "]\n");
// Keep track of how many call sites are added by the inlining...
unsigned NumCalls = FCs.size();
// Resolve the arguments and return value
G.mergeInGraph(Call, GI, DSGraph::StripAllocaBit |
DSGraph::DontCloneCallNodes);
// Added a call site?
if (FCs.size() != NumCalls) {
// Otherwise we need to inline the graph. Temporarily add the
// current function to the InProcess map to be able to handle
// recursion successfully.
//
I = InProcess.insert(I, std::make_pair(&FI, Call));
// ResolveFunctionCalls - Resolve the function calls that just got
// inlined...
//
Changed |= ResolveFunctionCalls(G, NumCalls, InProcess, Indent+1);
// Now that we are done processing the inlined graph, remove our
// cycle detector record...
//
//InProcess.erase(I);
}
}
}
}
if (hasExternalTarget) {
// If we cannot resolve this call site...
++FirstResolvableCall;
} else {
Changed = true;
FCs.erase(FCs.begin()+FirstResolvableCall);
}
}
}
return Changed;
}
DSGraph &BUDataStructures::calculateGraph(Function &F, unsigned Indent) {
// Make sure this graph has not already been calculated, or that we don't get
// into an infinite loop with mutually recursive functions.
//
DSGraph *&GraphPtr = DSInfo[&F];
if (GraphPtr) return *GraphPtr;
// Copy the local version into DSInfo...
GraphPtr = new DSGraph(getAnalysis<LocalDataStructures>().getDSGraph(F));
DSGraph &Graph = *GraphPtr;
Graph.setGlobalsGraph(GlobalsGraph);
Graph.setPrintAuxCalls();
// Start resolving calls...
std::vector<DSCallSite> &FCs = Graph.getAuxFunctionCalls();
// Start with a copy of the original call sites...
FCs = Graph.getFunctionCalls();
DEBUG(std::cerr << std::string(Indent*2, ' ')
<< "[BU] Calculating graph for: " << F.getName() << "\n");
bool Changed;
while (1) {
unsigned FirstResolvableCall = 0;
std::map<Function *, DSCallSite> InProcess;
// Insert a call site for self to handle self recursion...
std::vector<DSNodeHandle> Args;
Args.reserve(F.asize());
for (Function::aiterator I = F.abegin(), E = F.aend(); I != E; ++I)
if (isPointerType(I->getType()))
Args.push_back(Graph.getNodeForValue(I));
InProcess.insert(std::make_pair(&F,
DSCallSite(*(CallInst*)0, Graph.getRetNode(),(DSNode*)0,Args)));
Changed = ResolveFunctionCalls(Graph, FirstResolvableCall, InProcess,
Indent);
if (Changed) {
Graph.maskIncompleteMarkers();
Graph.markIncompleteNodes();
Graph.removeDeadNodes();
break;
} else {
break;
}
}
#if 0
bool Inlined;
do {
Inlined = false;
for (unsigned i = 0; i != FCs.size(); ++i) {
// Copy the call, because inlining graphs may invalidate the FCs vector.
DSCallSite Call = FCs[i];
// If the function list is complete...
if ((Call.getCallee().getNode()->NodeType & DSNode::Incomplete)==0) {
// Start inlining all of the functions we can... some may not be
// inlinable if they are external...
//
std::vector<GlobalValue*> Callees =
Call.getCallee().getNode()->getGlobals();
unsigned OldNumCalls = FCs.size();
// Loop over the functions, inlining whatever we can...
for (unsigned c = 0; c != Callees.size(); ++c) {
// Must be a function type, so this cast MUST succeed.
Function &FI = cast<Function>(*Callees[c]);
if (&FI == &F) {
// Self recursion... simply link up the formal arguments with the
// actual arguments...
DEBUG(std::cerr << std::string(Indent*2, ' ')
<< "[BU] Self Inlining: " << F.getName() << "\n");
// Handle self recursion by resolving the arguments and return value
Graph.mergeInGraph(Call, Graph, DSGraph::StripAllocaBit);
// Erase the entry in the callees vector
Callees.erase(Callees.begin()+c--);
} else if (!FI.isExternal()) {
DEBUG(std::cerr << std::string(Indent*2, ' ')
<< "[BU] In " << F.getName() << " inlining: "
<< FI.getName() << "\n");
// Get the data structure graph for the called function, closing it
// if possible (which is only impossible in the case of mutual
// recursion...
//
DSGraph &GI = calculateGraph(FI, Indent+1); // Graph to inline
DEBUG(std::cerr << std::string(Indent*2, ' ')
<< "[BU] Got graph for " << FI.getName()
<< " in: " << F.getName() << "[" << GI.getGraphSize() << "+"
<< GI.getAuxFunctionCalls().size() << "]\n");
// Handle self recursion by resolving the arguments and return value
Graph.mergeInGraph(Call, GI, DSGraph::StripAllocaBit |
DSGraph::DontCloneCallNodes);
// Erase the entry in the Callees vector
Callees.erase(Callees.begin()+c--);
} else if (FI.getName() == "printf" || FI.getName() == "sscanf" ||
FI.getName() == "fprintf" || FI.getName() == "open" ||
FI.getName() == "sprintf" || FI.getName() == "fputs") {
// FIXME: These special cases (eg printf) should go away when we can
// define functions that take a variable number of arguments.
// FIXME: at the very least, this should update mod/ref info
// Erase the entry in the globals vector
Callees.erase(Callees.begin()+c--);
}
}
if (Callees.empty()) { // Inlined all of the function calls?
// Erase the call if it is resolvable...
FCs.erase(FCs.begin()+i--); // Don't skip a the next call...
Inlined = true;
} else if (Callees.size() !=
Call.getCallee().getNode()->getGlobals().size()) {
// Was able to inline SOME, but not all of the functions. Construct a
// new global node here.
//
assert(0 && "Unimpl!");
Inlined = true;
}
#if 0
// If we just inlined a function that had call nodes, chances are that
// the call nodes are redundant with ones we already have. Eliminate
// those call nodes now.
//
if (FCs.size() >= OldNumCalls)
Graph.removeTriviallyDeadNodes();
#endif
}
if (FCs.size() > 200) {
std::cerr << "Aborted inlining fn: '" << F.getName() << "'!"
<< std::endl;
Graph.maskIncompleteMarkers();
Graph.markIncompleteNodes();
Graph.removeDeadNodes();
Graph.writeGraphToFile(std::cerr, "crap."+F.getName());
exit(1);
return Graph;
}
}
// Recompute the Incomplete markers. If there are any function calls left
// now that are complete, we must loop!
if (Inlined) {
Graph.maskIncompleteMarkers();
Graph.markIncompleteNodes();
Graph.removeDeadNodes();
}
// Loop over all of the resolvable call sites
unsigned LastCallSiteIdx = ~0U;
for (CallSiteIterator I = CallSiteIterator::begin(TempFCs),
E = CallSiteIterator::end(TempFCs); I != E; ++I) {
// If we skipped over any call sites, they must be unresolvable, copy them
// to the real call site list.
LastCallSiteIdx++;
for (; LastCallSiteIdx < I.getCallSiteIdx(); ++LastCallSiteIdx)
AuxCallsList.push_back(TempFCs[LastCallSiteIdx]);
LastCallSiteIdx = I.getCallSiteIdx();
} while (Inlined && !FCs.empty());
#endif
// Resolve the current call...
Function *Callee = *I;
DSCallSite &CS = I.getCallSite();
DEBUG(std::cerr << std::string(Indent*2, ' ')
<< "[BU] Done inlining: " << F.getName() << " ["
if (Callee->isExternal()) {
// Ignore this case, simple varargs functions we cannot stub out!
} else if (Callee == &F) {
// Self recursion... simply link up the formal arguments with the
// actual arguments...
DEBUG(std::cerr << " Self Inlining: " << F.getName() << "\n");
// Handle self recursion by resolving the arguments and return value
Graph.mergeInGraph(CS, Graph, 0);
} else {
// Get the data structure graph for the called function.
//
DSGraph &GI = getDSGraph(*Callee); // Graph to inline
DEBUG(std::cerr << " Inlining graph for " << Callee->getName()
<< " in: " << F.getName() << "[" << GI.getGraphSize() << "+"
<< GI.getAuxFunctionCalls().size() << "]\n");
// Handle self recursion by resolving the arguments and return value
Graph.mergeInGraph(CS, GI, DSGraph::StripAllocaBit |
DSGraph::DontCloneCallNodes);
}
}
// Make sure to catch any leftover unresolvable calls...
for (++LastCallSiteIdx; LastCallSiteIdx < TempFCs.size(); ++LastCallSiteIdx)
AuxCallsList.push_back(TempFCs[LastCallSiteIdx]);
TempFCs.clear();
// Recompute the Incomplete markers. If there are any function calls left
// now that are complete, we must loop!
Graph.maskIncompleteMarkers();
Graph.markIncompleteNodes();
Graph.removeDeadNodes();
DEBUG(std::cerr << " [BU] Done inlining: " << F.getName() << " ["
<< Graph.getGraphSize() << "+" << Graph.getAuxFunctionCalls().size()
<< "]\n");
Graph.writeGraphToFile(std::cerr, "bu_" + F.getName());
//Graph.writeGraphToFile(std::cerr, "bu_" + F.getName());
return Graph;
}
DSGraph &BUDataStructures::calculateSCCGraph(Function &F,
std::set<Function*> &InlinedSCCFunctions) {
DSGraph &Graph = getDSGraph(F);
DEBUG(std::cerr << " [BU] Calculating SCC graph for: " << F.getName()<<"\n");
std::vector<DSCallSite> UnresolvableCalls;
std::map<Function*, DSCallSite> SCCCallSiteMap;
std::vector<DSCallSite> &AuxCallsList = Graph.getAuxFunctionCalls();
while (1) { // Loop until we run out of resolvable call sites!
// Move our call site list into TempFCs so that inline call sites go into
// the new call site list and doesn't invalidate our iterators!
std::vector<DSCallSite> TempFCs;
TempFCs.swap(AuxCallsList);
// Loop over all of the resolvable call sites
unsigned LastCallSiteIdx = ~0U;
CallSiteIterator I = CallSiteIterator::begin(TempFCs),
E = CallSiteIterator::end(TempFCs);
if (I == E) {
TempFCs.swap(AuxCallsList);
break; // Done when no resolvable call sites exist
}
for (; I != E; ++I) {
// If we skipped over any call sites, they must be unresolvable, copy them
// to the unresolvable site list.
LastCallSiteIdx++;
for (; LastCallSiteIdx < I.getCallSiteIdx(); ++LastCallSiteIdx)
UnresolvableCalls.push_back(TempFCs[LastCallSiteIdx]);
LastCallSiteIdx = I.getCallSiteIdx();
// Resolve the current call...
Function *Callee = *I;
DSCallSite &CS = I.getCallSite();
if (Callee->isExternal()) {
// Ignore this case, simple varargs functions we cannot stub out!
} else if (Callee == &F) {
// Self recursion... simply link up the formal arguments with the
// actual arguments...
DEBUG(std::cerr << " Self Inlining: " << F.getName() << "\n");
// Handle self recursion by resolving the arguments and return value
Graph.mergeInGraph(CS, Graph, 0);
} else if (SCCCallSiteMap.count(Callee)) {
// We have already seen a call site in the SCC for this function, just
// merge the two call sites together and we are done.
SCCCallSiteMap.find(Callee)->second.mergeWith(CS);
} else {
// Get the data structure graph for the called function.
//
DSGraph &GI = getDSGraph(*Callee); // Graph to inline
DEBUG(std::cerr << " Inlining graph for " << Callee->getName()
<< " in: " << F.getName() << "[" << GI.getGraphSize() << "+"
<< GI.getAuxFunctionCalls().size() << "]\n");
// Handle self recursion by resolving the arguments and return value
Graph.mergeInGraph(CS, GI, DSGraph::StripAllocaBit |
DSGraph::DontCloneCallNodes);
if (InlinedSCCFunctions.count(Callee))
SCCCallSiteMap.insert(std::make_pair(Callee, CS));
}
}
// Make sure to catch any leftover unresolvable calls...
for (++LastCallSiteIdx; LastCallSiteIdx < TempFCs.size(); ++LastCallSiteIdx)
UnresolvableCalls.push_back(TempFCs[LastCallSiteIdx]);
}
// Reset the SCCCallSiteMap...
SCCCallSiteMap.clear();
AuxCallsList.insert(AuxCallsList.end(), UnresolvableCalls.begin(),
UnresolvableCalls.end());
UnresolvableCalls.clear();
// Recompute the Incomplete markers. If there are any function calls left
// now that are complete, we must loop!
Graph.maskIncompleteMarkers();
Graph.markIncompleteNodes();
Graph.removeDeadNodes();
DEBUG(std::cerr << " [BU] Done inlining: " << F.getName() << " ["
<< Graph.getGraphSize() << "+" << Graph.getAuxFunctionCalls().size()
<< "]\n");
//Graph.writeGraphToFile(std::cerr, "bu_" + F.getName());
return Graph;
}