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//===- CompleteBottomUp.cpp - Complete Bottom-Up Data Structure Graphs ----===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This is the exact same as the bottom-up graphs, but we use take a completed
// call graph and inline all indirect callees into their callers graphs, making
// the result more useful for things like pool allocation.
//
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/DataStructure.h"
#include "llvm/Module.h"
#include "llvm/Analysis/DSGraph.h"
#include "Support/SCCIterator.h"
#include "Support/STLExtras.h"
using namespace llvm;
namespace {
RegisterAnalysis<CompleteBUDataStructures>
X("cbudatastructure", "'Complete' Bottom-up Data Structure Analysis");
}
// run - Calculate the bottom up data structure graphs for each function in the
// program.
//
bool CompleteBUDataStructures::run(Module &M) {
BUDataStructures &BU = getAnalysis<BUDataStructures>();
GlobalsGraph = new DSGraph(BU.getGlobalsGraph());
GlobalsGraph->setPrintAuxCalls();
// Our call graph is the same as the BU data structures call graph
ActualCallees = BU.getActualCallees();
#if 1 // REMOVE ME EVENTUALLY
// FIXME: TEMPORARY (remove once finalization of indirect call sites in the
// globals graph has been implemented in the BU pass)
TDDataStructures &TD = getAnalysis<TDDataStructures>();
// The call graph extractable from the TD pass is _much more complete_ and
// trustable than that generated by the BU pass so far. Until this is fixed,
// we hack it like this:
for (Module::iterator MI = M.begin(), ME = M.end(); MI != ME; ++MI) {
if (MI->isExternal()) continue;
const std::vector<DSCallSite> &CSs = TD.getDSGraph(*MI).getFunctionCalls();
for (unsigned CSi = 0, e = CSs.size(); CSi != e; ++CSi) {
if (CSs[CSi].isIndirectCall()) {
Instruction *TheCall = CSs[CSi].getCallSite().getInstruction();
const std::vector<GlobalValue*> &Callees =
CSs[CSi].getCalleeNode()->getGlobals();
for (unsigned i = 0, e = Callees.size(); i != e; ++i)
if (Function *F = dyn_cast<Function>(Callees[i]))
ActualCallees.insert(std::make_pair(TheCall, F));
}
}
}
#endif
std::vector<DSGraph*> Stack;
hash_map<DSGraph*, unsigned> ValMap;
unsigned NextID = 1;
if (Function *Main = M.getMainFunction()) {
calculateSCCGraphs(getOrCreateGraph(*Main), Stack, NextID, ValMap);
} else {
std::cerr << "CBU-DSA: No 'main' function found!\n";
}
for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
if (!I->isExternal() && !DSInfo.count(I))
calculateSCCGraphs(getOrCreateGraph(*I), Stack, NextID, ValMap);
return false;
}
DSGraph &CompleteBUDataStructures::getOrCreateGraph(Function &F) {
// Has the graph already been created?
DSGraph *&Graph = DSInfo[&F];
if (Graph) return *Graph;
// Copy the BU graph...
Graph = new DSGraph(getAnalysis<BUDataStructures>().getDSGraph(F));
Graph->setGlobalsGraph(GlobalsGraph);
Graph->setPrintAuxCalls();
// Make sure to update the DSInfo map for all of the functions currently in
// this graph!
for (DSGraph::ReturnNodesTy::iterator I = Graph->getReturnNodes().begin();
I != Graph->getReturnNodes().end(); ++I)
DSInfo[I->first] = Graph;
return *Graph;
}
unsigned CompleteBUDataStructures::calculateSCCGraphs(DSGraph &FG,
std::vector<DSGraph*> &Stack,
unsigned &NextID,
hash_map<DSGraph*, unsigned> &ValMap) {
assert(!ValMap.count(&FG) && "Shouldn't revisit functions!");
unsigned Min = NextID++, MyID = Min;
ValMap[&FG] = Min;
Stack.push_back(&FG);
// The edges out of the current node are the call site targets...
for (unsigned i = 0, e = FG.getFunctionCalls().size(); i != e; ++i) {
Instruction *Call = FG.getFunctionCalls()[i].getCallSite().getInstruction();
// Loop over all of the actually called functions...
ActualCalleesTy::iterator I, E;
for (tie(I, E) = ActualCallees.equal_range(Call); I != E; ++I) {
DSGraph &Callee = getOrCreateGraph(*I->second);
unsigned M;
// Have we visited the destination function yet?
hash_map<DSGraph*, unsigned>::iterator It = ValMap.find(&Callee);
if (It == ValMap.end()) // No, visit it now.
M = calculateSCCGraphs(Callee, Stack, NextID, ValMap);
else // Yes, get it's number.
M = It->second;
if (M < Min) Min = M;
}
}
assert(ValMap[&FG] == 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.
bool IsMultiNodeSCC = false;
while (Stack.back() != &FG) {
DSGraph *NG = Stack.back();
ValMap[NG] = ~0U;
DSGraph::NodeMapTy NodeMap;
FG.cloneInto(*NG, FG.getScalarMap(), FG.getReturnNodes(), NodeMap, 0);
// Update the DSInfo map and delete the old graph...
for (DSGraph::ReturnNodesTy::iterator I = NG->getReturnNodes().begin();
I != NG->getReturnNodes().end(); ++I)
DSInfo[I->first] = &FG;
delete NG;
Stack.pop_back();
IsMultiNodeSCC = true;
}
// Clean up the graph before we start inlining a bunch again...
if (IsMultiNodeSCC)
FG.removeTriviallyDeadNodes();
Stack.pop_back();
processGraph(FG);
ValMap[&FG] = ~0U;
return MyID;
}
/// processGraph - Process the BU graphs for the program in bottom-up order on
/// the SCC of the __ACTUAL__ call graph. This builds "complete" BU graphs.
void CompleteBUDataStructures::processGraph(DSGraph &G) {
// The edges out of the current node are the call site targets...
for (unsigned i = 0, e = G.getFunctionCalls().size(); i != e; ++i) {
const DSCallSite &CS = G.getFunctionCalls()[i];
Instruction *TheCall = CS.getCallSite().getInstruction();
// The Normal BU pass will have taken care of direct calls well already,
// don't worry about them.
if (!CS.getCallSite().getCalledFunction()) {
// Loop over all of the actually called functions...
ActualCalleesTy::iterator I, E;
for (tie(I, E) = ActualCallees.equal_range(TheCall); I != E; ++I) {
Function *CalleeFunc = I->second;
if (!CalleeFunc->isExternal()) {
// Merge the callee's graph into this graph. This works for normal
// calls or for self recursion within an SCC.
G.mergeInGraph(CS, *CalleeFunc, getOrCreateGraph(*CalleeFunc),
DSGraph::KeepModRefBits |
DSGraph::StripAllocaBit |
DSGraph::DontCloneCallNodes);
}
}
}
}
// Re-materialize nodes from the globals graph.
// Do not ignore globals inlined from callees -- they are not up-to-date!
G.getInlinedGlobals().clear();
G.updateFromGlobalGraph();
// Recompute the Incomplete markers
G.maskIncompleteMarkers();
G.markIncompleteNodes(DSGraph::MarkFormalArgs);
// Delete dead nodes. Treat globals that are unreachable but that can
// reach live nodes as live.
G.removeDeadNodes(DSGraph::KeepUnreachableGlobals);
}
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