llvm-6502/lib/Analysis/DataStructure/BottomUpClosure.cpp
Chris Lattner 8a5db46967 Fix infinite loop in the BU algorithm. Unfortunately this dies a serious
death when handling moderately sized SCC's, but what can you do


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@4689 91177308-0d34-0410-b5e6-96231b3b80d8
2002-11-11 00:01:34 +00:00

340 lines
12 KiB
C++

//===- BottomUpClosure.cpp - Compute bottom-up interprocedural closure ----===//
//
// This file implements the BUDataStructures class, which represents the
// Bottom-Up Interprocedural closure of the data structure graph over the
// program. This is useful for applications like pool allocation, but **not**
// applications like alias analysis.
//
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/DataStructure.h"
#include "llvm/Analysis/DSGraph.h"
#include "llvm/Module.h"
#include "Support/Statistic.h"
using std::map;
static RegisterAnalysis<BUDataStructures>
X("budatastructure", "Bottom-up Data Structure Analysis Closure");
using namespace DS;
// 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...
for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
if (!I->isExternal())
calculateGraph(*I, 0);
return false;
}
// releaseMemory - If the pass pipeline is done with this pass, we can release
// our memory... here...
//
void BUDataStructures::releaseMemory() {
for (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();
delete GlobalsGraph;
GlobalsGraph = 0;
}
// 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;
// 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();
}
} while (Inlined && !FCs.empty());
#endif
DEBUG(std::cerr << std::string(Indent*2, ' ')
<< "[BU] Done inlining: " << F.getName() << " ["
<< Graph.getGraphSize() << "+" << Graph.getAuxFunctionCalls().size()
<< "]\n");
Graph.writeGraphToFile(std::cerr, "bu_" + F.getName());
return Graph;
}