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//===- TopDownClosure.cpp - Compute the top-down interprocedure closure ---===//
//
// This file implements the TDDataStructures class, which represents the
// Top-down Interprocedural closure of the data structure graph over the
// program. This is useful (but not strictly necessary?) for applications
// like pointer analysis.
//
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/DataStructure.h"
#include "llvm/Analysis/DSGraph.h"
#include "llvm/Module.h"
#include "llvm/DerivedTypes.h"
#include "Support/Statistic.h"
#include <set>
static RegisterAnalysis<TDDataStructures>
Y("tddatastructure", "Top-down Data Structure Analysis Closure");
// releaseMemory - If the pass pipeline is done with this pass, we can release
// our memory... here...
//
void TDDataStructures::releaseMemory() {
BUMaps.clear();
for (std::map<const Function*, DSGraph*>::iterator I = DSInfo.begin(),
E = DSInfo.end(); I != E; ++I)
delete I->second;
// Empty map so next time memory is released, data structures are not
// re-deleted.
DSInfo.clear();
}
// run - Calculate the top down data structure graphs for each function in the
// program.
//
bool TDDataStructures::run(Module &M) {
BUDataStructures &BU = getAnalysis<BUDataStructures>();
// Calculate the CallSitesForFunction mapping from the BU info...
for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
if (!I->isExternal())
if (const std::vector<DSCallSite> *CS = BU.getCallSites(*I))
for (unsigned i = 0, e = CS->size(); i != e; ++i)
if (Function *F = (*CS)[i].getResolvingCaller())
CallSitesForFunction[F].push_back(&(*CS)[i]);
// Next calculate the graphs for each function...
for (Module::reverse_iterator I = M.rbegin(), E = M.rend(); I != E; ++I)
if (!I->isExternal())
calculateGraph(*I);
// Destroy the temporary mapping...
CallSitesForFunction.clear();
return false;
}
/// ResolveCallSite - This method is used to link the actual arguments together
/// with the formal arguments for a function call in the top-down closure. This
/// method assumes that the call site arguments have been mapped into nodes
/// local to the specified graph.
///
void TDDataStructures::ResolveCallSite(DSGraph &Graph,
const DSCallSite &CallSite) {
// Resolve all of the function formal arguments...
Function &F = Graph.getFunction();
Function::aiterator AI = F.abegin();
for (unsigned i = 0, e = CallSite.getNumPtrArgs(); i != e; ++i, ++AI) {
// Advance the argument iterator to the first pointer argument...
while (!DS::isPointerType(AI->getType())) ++AI;
// TD ...Merge the formal arg scalar with the actual arg node
DSNodeHandle &NodeForFormal = Graph.getNodeForValue(AI);
assert(NodeForFormal.getNode() && "Pointer argument has no dest node!");
NodeForFormal.mergeWith(CallSite.getPtrArg(i));
}
// Merge returned node in the caller with the "return" node in callee
if (CallSite.getRetVal().getNode() && Graph.getRetNode().getNode())
Graph.getRetNode().mergeWith(CallSite.getRetVal());
}
DSGraph &TDDataStructures::calculateGraph(Function &F) {
// Make sure this graph has not already been calculated, or that we don't get
// into an infinite loop with mutually recursive functions.
//
DSGraph *&Graph = DSInfo[&F];
if (Graph) return *Graph;
BUDataStructures &BU = getAnalysis<BUDataStructures>();
DSGraph &BUGraph = BU.getDSGraph(F);
// Copy the BU graph, keeping a mapping from the BUGraph to the current Graph
std::map<const DSNode*, DSNodeHandle> BUNodeMap;
Graph = new DSGraph(BUGraph, BUNodeMap);
// We only need the BUMap entries for the nodes that are used in call sites.
// Calculate which nodes are needed.
std::set<const DSNode*> NeededNodes;
std::map<const Function*, std::vector<const DSCallSite*> >::iterator CSFFI
= CallSitesForFunction.find(&F);
if (CSFFI == CallSitesForFunction.end()) {
BUNodeMap.clear(); // No nodes are neccesary
} else {
std::vector<const DSCallSite*> &CSV = CSFFI->second;
for (unsigned i = 0, e = CSV.size(); i != e; ++i) {
NeededNodes.insert(CSV[i]->getRetVal().getNode());
for (unsigned j = 0, je = CSV[i]->getNumPtrArgs(); j != je; ++j)
NeededNodes.insert(CSV[i]->getPtrArg(j).getNode());
}
}
// Loop through te BUNodeMap, keeping only the nodes that are "Needed"
for (std::map<const DSNode*, DSNodeHandle>::iterator I = BUNodeMap.begin();
I != BUNodeMap.end(); )
if (NeededNodes.count(I->first) && I->first) // Keep needed nodes...
++I;
else {
std::map<const DSNode*, DSNodeHandle>::iterator J = I++;
BUNodeMap.erase(J);
}
NeededNodes.clear(); // We are done with this temporary data structure
// Convert the mapping from a node-to-node map into a node-to-nodehandle map
BUNodeMapTy &BUMap = BUMaps[&F];
BUMap.insert(BUNodeMap.begin(), BUNodeMap.end());
BUNodeMap.clear(); // We are done with the temporary map.
const std::vector<DSCallSite> *CallSitesP = BU.getCallSites(F);
if (CallSitesP == 0) {
DEBUG(std::cerr << " [TD] No callers for: " << F.getName() << "\n");
return *Graph; // If no call sites, the graph is the same as the BU graph!
}
// Loop over all call sites of this function, merging each one into this
// graph.
//
DEBUG(std::cerr << " [TD] Inlining " << CallSitesP->size()
<< " callers for: " << F.getName() << "\n");
const std::vector<DSCallSite> &CallSites = *CallSitesP;
for (unsigned c = 0, ce = CallSites.size(); c != ce; ++c) {
const DSCallSite &CallSite = CallSites[c];
Function &Caller = *CallSite.getResolvingCaller();
assert(&Caller && !Caller.isExternal() &&
"Externals function cannot 'call'!");
DEBUG(std::cerr << "\t [TD] Inlining caller #" << c << " '"
<< Caller.getName() << "' into callee: " << F.getName() << "\n");
// Self recursion is not tracked in BU pass...
assert(&Caller != &F && "This cannot happen!\n");
// Recursively compute the graph for the Caller. It should be fully
// resolved except if there is mutual recursion...
//
DSGraph &CG = calculateGraph(Caller); // Graph to inline
DEBUG(std::cerr << "\t\t[TD] Got graph for " << Caller.getName()
<< " in: " << F.getName() << "\n");
// Translate call site from having links into the BU graph
DSCallSite CallSiteInCG(CallSite, BUMaps[&Caller]);
// These two maps keep track of where scalars in the old graph _used_
// to point to, and of new nodes matching nodes of the old graph.
std::map<Value*, DSNodeHandle> OldValMap;
std::map<const DSNode*, DSNodeHandle> OldNodeMap;
// FIXME: Eventually use DSGraph::mergeInGraph here...
// Graph->mergeInGraph(CallSiteInCG, CG, false);
// Clone the Caller's graph into the current graph, keeping
// track of where scalars in the old graph _used_ to point...
// Do this here because it only needs to happens once for each Caller!
// Strip scalars but not allocas since they are alive in callee.
//
DSNodeHandle RetVal = Graph->cloneInto(CG, OldValMap, OldNodeMap,
DSGraph::KeepAllocaBit);
ResolveCallSite(*Graph, DSCallSite(CallSiteInCG, OldNodeMap));
}
// Recompute the Incomplete markers and eliminate unreachable nodes.
Graph->maskIncompleteMarkers();
Graph->markIncompleteNodes(/*markFormals*/ !F.hasInternalLinkage()
/*&& FIXME: NEED TO CHECK IF ALL CALLERS FOUND!*/);
Graph->removeDeadNodes(/*KeepAllGlobals*/ false, /*KeepCalls*/ false);
DEBUG(std::cerr << " [TD] Done inlining callers for: " << F.getName() << " ["
<< Graph->getGraphSize() << "+" << Graph->getFunctionCalls().size()
<< "]\n");
return *Graph;
}
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