//===- CallGraphSCCPass.cpp - Pass that operates BU on call graph ---------===//
-//
+//
// 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 file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
//===----------------------------------------------------------------------===//
//
// This file implements the CallGraphSCCPass class, which is used for passes
//
//===----------------------------------------------------------------------===//
+#define DEBUG_TYPE "cgscc-passmgr"
#include "llvm/CallGraphSCCPass.h"
#include "llvm/Analysis/CallGraph.h"
-#include "Support/SCCIterator.h"
+#include "llvm/ADT/SCCIterator.h"
+#include "llvm/PassManagers.h"
+#include "llvm/Function.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/IntrinsicInst.h"
+#include "llvm/Support/raw_ostream.h"
+using namespace llvm;
-namespace llvm {
+//===----------------------------------------------------------------------===//
+// CGPassManager
+//
+/// CGPassManager manages FPPassManagers and CalLGraphSCCPasses.
-/// getAnalysisUsage - For this class, we declare that we require and preserve
-/// the call graph. If the derived class implements this method, it should
-/// always explicitly call the implementation here.
-void CallGraphSCCPass::getAnalysisUsage(AnalysisUsage &AU) const {
- AU.addRequired<CallGraph>();
- AU.addPreserved<CallGraph>();
+namespace {
+
+class CGPassManager : public ModulePass, public PMDataManager {
+public:
+ static char ID;
+ explicit CGPassManager(int Depth)
+ : ModulePass(&ID), PMDataManager(Depth) { }
+
+ /// run - Execute all of the passes scheduled for execution. Keep track of
+ /// whether any of the passes modifies the module, and if so, return true.
+ bool runOnModule(Module &M);
+
+ bool doInitialization(CallGraph &CG);
+ bool doFinalization(CallGraph &CG);
+
+ /// Pass Manager itself does not invalidate any analysis info.
+ void getAnalysisUsage(AnalysisUsage &Info) const {
+ // CGPassManager walks SCC and it needs CallGraph.
+ Info.addRequired<CallGraph>();
+ Info.setPreservesAll();
+ }
+
+ virtual const char *getPassName() const {
+ return "CallGraph Pass Manager";
+ }
+
+ // Print passes managed by this manager
+ void dumpPassStructure(unsigned Offset) {
+ errs().indent(Offset*2) << "Call Graph SCC Pass Manager\n";
+ for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
+ Pass *P = getContainedPass(Index);
+ P->dumpPassStructure(Offset + 1);
+ dumpLastUses(P, Offset+1);
+ }
+ }
+
+ Pass *getContainedPass(unsigned N) {
+ assert(N < PassVector.size() && "Pass number out of range!");
+ return static_cast<Pass *>(PassVector[N]);
+ }
+
+ virtual PassManagerType getPassManagerType() const {
+ return PMT_CallGraphPassManager;
+ }
+
+private:
+ bool RunPassOnSCC(Pass *P, std::vector<CallGraphNode*> &CurSCC,
+ CallGraph &CG, bool &CallGraphUpToDate);
+ void RefreshCallGraph(std::vector<CallGraphNode*> &CurSCC, CallGraph &CG,
+ bool IsCheckingMode);
+};
+
+} // end anonymous namespace.
+
+char CGPassManager::ID = 0;
+
+bool CGPassManager::RunPassOnSCC(Pass *P, std::vector<CallGraphNode*> &CurSCC,
+ CallGraph &CG, bool &CallGraphUpToDate) {
+ bool Changed = false;
+ if (CallGraphSCCPass *CGSP = dynamic_cast<CallGraphSCCPass*>(P)) {
+ if (!CallGraphUpToDate) {
+ RefreshCallGraph(CurSCC, CG, false);
+ CallGraphUpToDate = true;
+ }
+
+ StartPassTimer(CGSP);
+ Changed = CGSP->runOnSCC(CurSCC);
+ StopPassTimer(CGSP);
+
+ // After the CGSCCPass is done, when assertions are enabled, use
+ // RefreshCallGraph to verify that the callgraph was correctly updated.
+#ifndef NDEBUG
+ if (Changed)
+ RefreshCallGraph(CurSCC, CG, true);
+#endif
+
+ return Changed;
+ }
+
+ StartPassTimer(P);
+ FPPassManager *FPP = dynamic_cast<FPPassManager *>(P);
+ assert(FPP && "Invalid CGPassManager member");
+
+ // Run pass P on all functions in the current SCC.
+ for (unsigned i = 0, e = CurSCC.size(); i != e; ++i) {
+ if (Function *F = CurSCC[i]->getFunction()) {
+ dumpPassInfo(P, EXECUTION_MSG, ON_FUNCTION_MSG, F->getName());
+ Changed |= FPP->runOnFunction(*F);
+ }
+ }
+ StopPassTimer(P);
+
+ // The function pass(es) modified the IR, they may have clobbered the
+ // callgraph.
+ if (Changed && CallGraphUpToDate) {
+ DEBUG(errs() << "CGSCCPASSMGR: Pass Dirtied SCC: "
+ << P->getPassName() << '\n');
+ CallGraphUpToDate = false;
+ }
+ return Changed;
}
-bool CallGraphSCCPass::run(Module &M) {
+
+/// RefreshCallGraph - Scan the functions in the specified CFG and resync the
+/// callgraph with the call sites found in it. This is used after
+/// FunctionPasses have potentially munged the callgraph, and can be used after
+/// CallGraphSCC passes to verify that they correctly updated the callgraph.
+///
+void CGPassManager::RefreshCallGraph(std::vector<CallGraphNode*> &CurSCC,
+ CallGraph &CG, bool CheckingMode) {
+ DenseMap<Value*, CallGraphNode*> CallSites;
+
+ DEBUG(errs() << "CGSCCPASSMGR: Refreshing SCC with " << CurSCC.size()
+ << " nodes:\n";
+ for (unsigned i = 0, e = CurSCC.size(); i != e; ++i)
+ CurSCC[i]->dump();
+ );
+
+ bool MadeChange = false;
+
+ // Scan all functions in the SCC.
+ for (unsigned sccidx = 0, e = CurSCC.size(); sccidx != e; ++sccidx) {
+ CallGraphNode *CGN = CurSCC[sccidx];
+ Function *F = CGN->getFunction();
+ if (F == 0 || F->isDeclaration()) continue;
+
+ // Walk the function body looking for call sites. Sync up the call sites in
+ // CGN with those actually in the function.
+
+ // Get the set of call sites currently in the function.
+ for (CallGraphNode::iterator I = CGN->begin(), E = CGN->end(); I != E; ){
+ // If this call site is null, then the function pass deleted the call
+ // entirely and the WeakVH nulled it out.
+ if (I->first == 0 ||
+ // If we've already seen this call site, then the FunctionPass RAUW'd
+ // one call with another, which resulted in two "uses" in the edge
+ // list of the same call.
+ CallSites.count(I->first) ||
+
+ // If the call edge is not from a call or invoke, then the function
+ // pass RAUW'd a call with another value. This can happen when
+ // constant folding happens of well known functions etc.
+ CallSite::get(I->first).getInstruction() == 0) {
+ assert(!CheckingMode &&
+ "CallGraphSCCPass did not update the CallGraph correctly!");
+
+ // Just remove the edge from the set of callees.
+ CGN->removeCallEdge(I);
+ E = CGN->end();
+ continue;
+ }
+
+ assert(!CallSites.count(I->first) &&
+ "Call site occurs in node multiple times");
+ CallSites.insert(std::make_pair(I->first, I->second));
+ ++I;
+ }
+
+ // Loop over all of the instructions in the function, getting the callsites.
+ for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB)
+ for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) {
+ CallSite CS = CallSite::get(I);
+ if (!CS.getInstruction() || isa<DbgInfoIntrinsic>(I)) continue;
+
+ // If this call site already existed in the callgraph, just verify it
+ // matches up to expectations and remove it from CallSites.
+ DenseMap<Value*, CallGraphNode*>::iterator ExistingIt =
+ CallSites.find(CS.getInstruction());
+ if (ExistingIt != CallSites.end()) {
+ CallGraphNode *ExistingNode = ExistingIt->second;
+
+ // Remove from CallSites since we have now seen it.
+ CallSites.erase(ExistingIt);
+
+ // Verify that the callee is right.
+ if (ExistingNode->getFunction() == CS.getCalledFunction())
+ continue;
+
+ // If we are in checking mode, we are not allowed to actually mutate
+ // the callgraph. If this is a case where we can infer that the
+ // callgraph is less precise than it could be (e.g. an indirect call
+ // site could be turned direct), don't reject it in checking mode, and
+ // don't tweak it to be more precise.
+ if (CheckingMode && CS.getCalledFunction() &&
+ ExistingNode->getFunction() == 0)
+ continue;
+
+ assert(!CheckingMode &&
+ "CallGraphSCCPass did not update the CallGraph correctly!");
+
+ // If not, we either went from a direct call to indirect, indirect to
+ // direct, or direct to different direct.
+ CallGraphNode *CalleeNode;
+ if (Function *Callee = CS.getCalledFunction())
+ CalleeNode = CG.getOrInsertFunction(Callee);
+ else
+ CalleeNode = CG.getCallsExternalNode();
+
+ // Update the edge target in CGN.
+ for (CallGraphNode::iterator I = CGN->begin(); ; ++I) {
+ assert(I != CGN->end() && "Didn't find call entry");
+ if (I->first == CS.getInstruction()) {
+ I->second = CalleeNode;
+ break;
+ }
+ }
+ MadeChange = true;
+ continue;
+ }
+
+ assert(!CheckingMode &&
+ "CallGraphSCCPass did not update the CallGraph correctly!");
+
+ // If the call site didn't exist in the CGN yet, add it. We assume that
+ // newly introduced call sites won't be indirect. This could be fixed
+ // in the future.
+ CallGraphNode *CalleeNode;
+ if (Function *Callee = CS.getCalledFunction())
+ CalleeNode = CG.getOrInsertFunction(Callee);
+ else
+ CalleeNode = CG.getCallsExternalNode();
+
+ CGN->addCalledFunction(CS, CalleeNode);
+ MadeChange = true;
+ }
+
+ // After scanning this function, if we still have entries in callsites, then
+ // they are dangling pointers. WeakVH should save us for this, so abort if
+ // this happens.
+ assert(CallSites.empty() && "Dangling pointers found in call sites map");
+
+ // Periodically do an explicit clear to remove tombstones when processing
+ // large scc's.
+ if ((sccidx & 15) == 0)
+ CallSites.clear();
+ }
+
+ DEBUG(if (MadeChange) {
+ errs() << "CGSCCPASSMGR: Refreshed SCC is now:\n";
+ for (unsigned i = 0, e = CurSCC.size(); i != e; ++i)
+ CurSCC[i]->dump();
+ } else {
+ errs() << "CGSCCPASSMGR: SCC Refresh didn't change call graph.\n";
+ }
+ );
+}
+
+/// run - Execute all of the passes scheduled for execution. Keep track of
+/// whether any of the passes modifies the module, and if so, return true.
+bool CGPassManager::runOnModule(Module &M) {
CallGraph &CG = getAnalysis<CallGraph>();
+ bool Changed = doInitialization(CG);
+
+ std::vector<CallGraphNode*> CurSCC;
+
+ // Walk the callgraph in bottom-up SCC order.
+ for (scc_iterator<CallGraph*> CGI = scc_begin(&CG), E = scc_end(&CG);
+ CGI != E;) {
+ // Copy the current SCC and increment past it so that the pass can hack
+ // on the SCC if it wants to without invalidating our iterator.
+ CurSCC = *CGI;
+ ++CGI;
+
+
+ // CallGraphUpToDate - Keep track of whether the callgraph is known to be
+ // up-to-date or not. The CGSSC pass manager runs two types of passes:
+ // CallGraphSCC Passes and other random function passes. Because other
+ // random function passes are not CallGraph aware, they may clobber the
+ // call graph by introducing new calls or deleting other ones. This flag
+ // is set to false when we run a function pass so that we know to clean up
+ // the callgraph when we need to run a CGSCCPass again.
+ bool CallGraphUpToDate = true;
+
+ // Run all passes on current SCC.
+ for (unsigned PassNo = 0, e = getNumContainedPasses();
+ PassNo != e; ++PassNo) {
+ Pass *P = getContainedPass(PassNo);
+
+ dumpPassInfo(P, EXECUTION_MSG, ON_CG_MSG, "");
+ dumpRequiredSet(P);
+
+ initializeAnalysisImpl(P);
+
+ // Actually run this pass on the current SCC.
+ Changed |= RunPassOnSCC(P, CurSCC, CG, CallGraphUpToDate);
+
+ if (Changed)
+ dumpPassInfo(P, MODIFICATION_MSG, ON_CG_MSG, "");
+ dumpPreservedSet(P);
+
+ verifyPreservedAnalysis(P);
+ removeNotPreservedAnalysis(P);
+ recordAvailableAnalysis(P);
+ removeDeadPasses(P, "", ON_CG_MSG);
+ }
+
+ // If the callgraph was left out of date (because the last pass run was a
+ // functionpass), refresh it before we move on to the next SCC.
+ if (!CallGraphUpToDate)
+ RefreshCallGraph(CurSCC, CG, false);
+ }
+ Changed |= doFinalization(CG);
+ return Changed;
+}
+
+/// Initialize CG
+bool CGPassManager::doInitialization(CallGraph &CG) {
+ bool Changed = false;
+ for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
+ Pass *P = getContainedPass(Index);
+ if (CallGraphSCCPass *CGSP = dynamic_cast<CallGraphSCCPass *>(P)) {
+ Changed |= CGSP->doInitialization(CG);
+ } else {
+ FPPassManager *FP = dynamic_cast<FPPassManager *>(P);
+ assert (FP && "Invalid CGPassManager member");
+ Changed |= FP->doInitialization(CG.getModule());
+ }
+ }
+ return Changed;
+}
+
+/// Finalize CG
+bool CGPassManager::doFinalization(CallGraph &CG) {
bool Changed = false;
- for (scc_iterator<CallGraph*> I = scc_begin(&CG), E = scc_end(&CG);
- I != E; ++I)
- Changed = runOnSCC(*I);
+ for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
+ Pass *P = getContainedPass(Index);
+ if (CallGraphSCCPass *CGSP = dynamic_cast<CallGraphSCCPass *>(P)) {
+ Changed |= CGSP->doFinalization(CG);
+ } else {
+ FPPassManager *FP = dynamic_cast<FPPassManager *>(P);
+ assert (FP && "Invalid CGPassManager member");
+ Changed |= FP->doFinalization(CG.getModule());
+ }
+ }
return Changed;
}
-} // End llvm namespace
+/// Assign pass manager to manage this pass.
+void CallGraphSCCPass::assignPassManager(PMStack &PMS,
+ PassManagerType PreferredType) {
+ // Find CGPassManager
+ while (!PMS.empty() &&
+ PMS.top()->getPassManagerType() > PMT_CallGraphPassManager)
+ PMS.pop();
+
+ assert (!PMS.empty() && "Unable to handle Call Graph Pass");
+ CGPassManager *CGP = dynamic_cast<CGPassManager *>(PMS.top());
+
+ // Create new Call Graph SCC Pass Manager if it does not exist.
+ if (!CGP) {
+
+ assert (!PMS.empty() && "Unable to create Call Graph Pass Manager");
+ PMDataManager *PMD = PMS.top();
+
+ // [1] Create new Call Graph Pass Manager
+ CGP = new CGPassManager(PMD->getDepth() + 1);
+
+ // [2] Set up new manager's top level manager
+ PMTopLevelManager *TPM = PMD->getTopLevelManager();
+ TPM->addIndirectPassManager(CGP);
+
+ // [3] Assign manager to manage this new manager. This may create
+ // and push new managers into PMS
+ Pass *P = dynamic_cast<Pass *>(CGP);
+ TPM->schedulePass(P);
+
+ // [4] Push new manager into PMS
+ PMS.push(CGP);
+ }
+
+ CGP->add(this);
+}
+
+/// getAnalysisUsage - For this class, we declare that we require and preserve
+/// the call graph. If the derived class implements this method, it should
+/// always explicitly call the implementation here.
+void CallGraphSCCPass::getAnalysisUsage(AnalysisUsage &AU) const {
+ AU.addRequired<CallGraph>();
+ AU.addPreserved<CallGraph>();
+}
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