//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "inline"
-#include "llvm/Module.h"
-#include "llvm/Instructions.h"
+#include "llvm/Transforms/IPO/InlinerPass.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/CallGraph.h"
+#include "llvm/Analysis/InlineCost.h"
+#include "llvm/DataLayout.h"
+#include "llvm/Instructions.h"
+#include "llvm/IntrinsicInst.h"
+#include "llvm/Module.h"
#include "llvm/Support/CallSite.h"
-#include "llvm/Target/TargetData.h"
-#include "llvm/Transforms/IPO/InlinerPass.h"
-#include "llvm/Transforms/Utils/Cloning.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
-#include "llvm/ADT/Statistic.h"
-#include <set>
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Target/TargetLibraryInfo.h"
+#include "llvm/Transforms/Utils/Cloning.h"
+#include "llvm/Transforms/Utils/Local.h"
using namespace llvm;
STATISTIC(NumInlined, "Number of functions inlined");
+STATISTIC(NumCallsDeleted, "Number of call sites deleted, not inlined");
STATISTIC(NumDeleted, "Number of functions deleted because all callers found");
+STATISTIC(NumMergedAllocas, "Number of allocas merged together");
+
+// This weirdly named statistic tracks the number of times that, when attempting
+// to inline a function A into B, we analyze the callers of B in order to see
+// if those would be more profitable and blocked inline steps.
+STATISTIC(NumCallerCallersAnalyzed, "Number of caller-callers analyzed");
static cl::opt<int>
-InlineLimit("inline-threshold", cl::Hidden, cl::init(200),
- cl::desc("Control the amount of inlining to perform (default = 200)"));
+InlineLimit("inline-threshold", cl::Hidden, cl::init(225), cl::ZeroOrMore,
+ cl::desc("Control the amount of inlining to perform (default = 225)"));
-Inliner::Inliner(void *ID)
- : CallGraphSCCPass(ID), InlineThreshold(InlineLimit) {}
+static cl::opt<int>
+HintThreshold("inlinehint-threshold", cl::Hidden, cl::init(325),
+ cl::desc("Threshold for inlining functions with inline hint"));
+
+// Threshold to use when optsize is specified (and there is no -inline-limit).
+const int OptSizeThreshold = 75;
+
+Inliner::Inliner(char &ID)
+ : CallGraphSCCPass(ID), InlineThreshold(InlineLimit), InsertLifetime(true) {}
-Inliner::Inliner(void *ID, int Threshold)
- : CallGraphSCCPass(ID), InlineThreshold(Threshold) {}
+Inliner::Inliner(char &ID, int Threshold, bool InsertLifetime)
+ : CallGraphSCCPass(ID), InlineThreshold(InlineLimit.getNumOccurrences() > 0 ?
+ InlineLimit : Threshold),
+ InsertLifetime(InsertLifetime) {}
/// 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 Inliner::getAnalysisUsage(AnalysisUsage &Info) const {
- Info.addRequired<TargetData>();
CallGraphSCCPass::getAnalysisUsage(Info);
}
-// InlineCallIfPossible - If it is possible to inline the specified call site,
-// do so and update the CallGraph for this operation.
-static bool InlineCallIfPossible(CallSite CS, CallGraph &CG,
- const std::set<Function*> &SCCFunctions,
- const TargetData &TD) {
+
+typedef DenseMap<ArrayType*, std::vector<AllocaInst*> >
+InlinedArrayAllocasTy;
+
+/// InlineCallIfPossible - If it is possible to inline the specified call site,
+/// do so and update the CallGraph for this operation.
+///
+/// This function also does some basic book-keeping to update the IR. The
+/// InlinedArrayAllocas map keeps track of any allocas that are already
+/// available from other functions inlined into the caller. If we are able to
+/// inline this call site we attempt to reuse already available allocas or add
+/// any new allocas to the set if not possible.
+static bool InlineCallIfPossible(CallSite CS, InlineFunctionInfo &IFI,
+ InlinedArrayAllocasTy &InlinedArrayAllocas,
+ int InlineHistory, bool InsertLifetime) {
Function *Callee = CS.getCalledFunction();
- if (!InlineFunction(CS, &CG, &TD)) return false;
+ Function *Caller = CS.getCaller();
- // If we inlined the last possible call site to the function, delete the
- // function body now.
- if (Callee->use_empty() && Callee->hasInternalLinkage() &&
- !SCCFunctions.count(Callee)) {
- DOUT << " -> Deleting dead function: " << Callee->getName() << "\n";
- CallGraphNode *CalleeNode = CG[Callee];
+ // Try to inline the function. Get the list of static allocas that were
+ // inlined.
+ if (!InlineFunction(CS, IFI, InsertLifetime))
+ return false;
- // Remove any call graph edges from the callee to its callees.
- CalleeNode->removeAllCalledFunctions();
+ // If the inlined function had a higher stack protection level than the
+ // calling function, then bump up the caller's stack protection level.
+ if (Callee->getFnAttributes().hasAttribute(Attributes::StackProtectReq))
+ Caller->addFnAttr(Attributes::StackProtectReq);
+ else if (Callee->getFnAttributes().hasAttribute(Attributes::StackProtect) &&
+ !Caller->getFnAttributes().hasAttribute(Attributes::StackProtectReq))
+ Caller->addFnAttr(Attributes::StackProtect);
- // Removing the node for callee from the call graph and delete it.
- delete CG.removeFunctionFromModule(CalleeNode);
- ++NumDeleted;
+ // Look at all of the allocas that we inlined through this call site. If we
+ // have already inlined other allocas through other calls into this function,
+ // then we know that they have disjoint lifetimes and that we can merge them.
+ //
+ // There are many heuristics possible for merging these allocas, and the
+ // different options have different tradeoffs. One thing that we *really*
+ // don't want to hurt is SRoA: once inlining happens, often allocas are no
+ // longer address taken and so they can be promoted.
+ //
+ // Our "solution" for that is to only merge allocas whose outermost type is an
+ // array type. These are usually not promoted because someone is using a
+ // variable index into them. These are also often the most important ones to
+ // merge.
+ //
+ // A better solution would be to have real memory lifetime markers in the IR
+ // and not have the inliner do any merging of allocas at all. This would
+ // allow the backend to do proper stack slot coloring of all allocas that
+ // *actually make it to the backend*, which is really what we want.
+ //
+ // Because we don't have this information, we do this simple and useful hack.
+ //
+ SmallPtrSet<AllocaInst*, 16> UsedAllocas;
+
+ // When processing our SCC, check to see if CS was inlined from some other
+ // call site. For example, if we're processing "A" in this code:
+ // A() { B() }
+ // B() { x = alloca ... C() }
+ // C() { y = alloca ... }
+ // Assume that C was not inlined into B initially, and so we're processing A
+ // and decide to inline B into A. Doing this makes an alloca available for
+ // reuse and makes a callsite (C) available for inlining. When we process
+ // the C call site we don't want to do any alloca merging between X and Y
+ // because their scopes are not disjoint. We could make this smarter by
+ // keeping track of the inline history for each alloca in the
+ // InlinedArrayAllocas but this isn't likely to be a significant win.
+ if (InlineHistory != -1) // Only do merging for top-level call sites in SCC.
+ return true;
+
+ // Loop over all the allocas we have so far and see if they can be merged with
+ // a previously inlined alloca. If not, remember that we had it.
+ for (unsigned AllocaNo = 0, e = IFI.StaticAllocas.size();
+ AllocaNo != e; ++AllocaNo) {
+ AllocaInst *AI = IFI.StaticAllocas[AllocaNo];
+
+ // Don't bother trying to merge array allocations (they will usually be
+ // canonicalized to be an allocation *of* an array), or allocations whose
+ // type is not itself an array (because we're afraid of pessimizing SRoA).
+ ArrayType *ATy = dyn_cast<ArrayType>(AI->getAllocatedType());
+ if (ATy == 0 || AI->isArrayAllocation())
+ continue;
+
+ // Get the list of all available allocas for this array type.
+ std::vector<AllocaInst*> &AllocasForType = InlinedArrayAllocas[ATy];
+
+ // Loop over the allocas in AllocasForType to see if we can reuse one. Note
+ // that we have to be careful not to reuse the same "available" alloca for
+ // multiple different allocas that we just inlined, we use the 'UsedAllocas'
+ // set to keep track of which "available" allocas are being used by this
+ // function. Also, AllocasForType can be empty of course!
+ bool MergedAwayAlloca = false;
+ for (unsigned i = 0, e = AllocasForType.size(); i != e; ++i) {
+ AllocaInst *AvailableAlloca = AllocasForType[i];
+
+ // The available alloca has to be in the right function, not in some other
+ // function in this SCC.
+ if (AvailableAlloca->getParent() != AI->getParent())
+ continue;
+
+ // If the inlined function already uses this alloca then we can't reuse
+ // it.
+ if (!UsedAllocas.insert(AvailableAlloca))
+ continue;
+
+ // Otherwise, we *can* reuse it, RAUW AI into AvailableAlloca and declare
+ // success!
+ DEBUG(dbgs() << " ***MERGED ALLOCA: " << *AI << "\n\t\tINTO: "
+ << *AvailableAlloca << '\n');
+
+ AI->replaceAllUsesWith(AvailableAlloca);
+ AI->eraseFromParent();
+ MergedAwayAlloca = true;
+ ++NumMergedAllocas;
+ IFI.StaticAllocas[AllocaNo] = 0;
+ break;
+ }
+
+ // If we already nuked the alloca, we're done with it.
+ if (MergedAwayAlloca)
+ continue;
+
+ // If we were unable to merge away the alloca either because there are no
+ // allocas of the right type available or because we reused them all
+ // already, remember that this alloca came from an inlined function and mark
+ // it used so we don't reuse it for other allocas from this inline
+ // operation.
+ AllocasForType.push_back(AI);
+ UsedAllocas.insert(AI);
}
+
+ return true;
+}
+
+unsigned Inliner::getInlineThreshold(CallSite CS) const {
+ int thres = InlineThreshold; // -inline-threshold or else selected by
+ // overall opt level
+
+ // If -inline-threshold is not given, listen to the optsize attribute when it
+ // would decrease the threshold.
+ Function *Caller = CS.getCaller();
+ bool OptSize = Caller && !Caller->isDeclaration() &&
+ Caller->getFnAttributes().hasAttribute(Attributes::OptimizeForSize);
+ if (!(InlineLimit.getNumOccurrences() > 0) && OptSize &&
+ OptSizeThreshold < thres)
+ thres = OptSizeThreshold;
+
+ // Listen to the inlinehint attribute when it would increase the threshold.
+ Function *Callee = CS.getCalledFunction();
+ bool InlineHint = Callee && !Callee->isDeclaration() &&
+ Callee->getFnAttributes().hasAttribute(Attributes::InlineHint);
+ if (InlineHint && HintThreshold > thres)
+ thres = HintThreshold;
+
+ return thres;
+}
+
+/// shouldInline - Return true if the inliner should attempt to inline
+/// at the given CallSite.
+bool Inliner::shouldInline(CallSite CS) {
+ InlineCost IC = getInlineCost(CS);
+
+ if (IC.isAlways()) {
+ DEBUG(dbgs() << " Inlining: cost=always"
+ << ", Call: " << *CS.getInstruction() << "\n");
+ return true;
+ }
+
+ if (IC.isNever()) {
+ DEBUG(dbgs() << " NOT Inlining: cost=never"
+ << ", Call: " << *CS.getInstruction() << "\n");
+ return false;
+ }
+
+ Function *Caller = CS.getCaller();
+ if (!IC) {
+ DEBUG(dbgs() << " NOT Inlining: cost=" << IC.getCost()
+ << ", thres=" << (IC.getCostDelta() + IC.getCost())
+ << ", Call: " << *CS.getInstruction() << "\n");
+ return false;
+ }
+
+ // Try to detect the case where the current inlining candidate caller (call
+ // it B) is a static or linkonce-ODR function and is an inlining candidate
+ // elsewhere, and the current candidate callee (call it C) is large enough
+ // that inlining it into B would make B too big to inline later. In these
+ // circumstances it may be best not to inline C into B, but to inline B into
+ // its callers.
+ //
+ // This only applies to static and linkonce-ODR functions because those are
+ // expected to be available for inlining in the translation units where they
+ // are used. Thus we will always have the opportunity to make local inlining
+ // decisions. Importantly the linkonce-ODR linkage covers inline functions
+ // and templates in C++.
+ //
+ // FIXME: All of this logic should be sunk into getInlineCost. It relies on
+ // the internal implementation of the inline cost metrics rather than
+ // treating them as truly abstract units etc.
+ if (Caller->hasLocalLinkage() ||
+ Caller->getLinkage() == GlobalValue::LinkOnceODRLinkage) {
+ int TotalSecondaryCost = 0;
+ // The candidate cost to be imposed upon the current function.
+ int CandidateCost = IC.getCost() - (InlineConstants::CallPenalty + 1);
+ // This bool tracks what happens if we do NOT inline C into B.
+ bool callerWillBeRemoved = Caller->hasLocalLinkage();
+ // This bool tracks what happens if we DO inline C into B.
+ bool inliningPreventsSomeOuterInline = false;
+ for (Value::use_iterator I = Caller->use_begin(), E =Caller->use_end();
+ I != E; ++I) {
+ CallSite CS2(*I);
+
+ // If this isn't a call to Caller (it could be some other sort
+ // of reference) skip it. Such references will prevent the caller
+ // from being removed.
+ if (!CS2 || CS2.getCalledFunction() != Caller) {
+ callerWillBeRemoved = false;
+ continue;
+ }
+
+ InlineCost IC2 = getInlineCost(CS2);
+ ++NumCallerCallersAnalyzed;
+ if (!IC2) {
+ callerWillBeRemoved = false;
+ continue;
+ }
+ if (IC2.isAlways())
+ continue;
+
+ // See if inlining or original callsite would erase the cost delta of
+ // this callsite. We subtract off the penalty for the call instruction,
+ // which we would be deleting.
+ if (IC2.getCostDelta() <= CandidateCost) {
+ inliningPreventsSomeOuterInline = true;
+ TotalSecondaryCost += IC2.getCost();
+ }
+ }
+ // If all outer calls to Caller would get inlined, the cost for the last
+ // one is set very low by getInlineCost, in anticipation that Caller will
+ // be removed entirely. We did not account for this above unless there
+ // is only one caller of Caller.
+ if (callerWillBeRemoved && Caller->use_begin() != Caller->use_end())
+ TotalSecondaryCost += InlineConstants::LastCallToStaticBonus;
+
+ if (inliningPreventsSomeOuterInline && TotalSecondaryCost < IC.getCost()) {
+ DEBUG(dbgs() << " NOT Inlining: " << *CS.getInstruction() <<
+ " Cost = " << IC.getCost() <<
+ ", outer Cost = " << TotalSecondaryCost << '\n');
+ return false;
+ }
+ }
+
+ DEBUG(dbgs() << " Inlining: cost=" << IC.getCost()
+ << ", thres=" << (IC.getCostDelta() + IC.getCost())
+ << ", Call: " << *CS.getInstruction() << '\n');
return true;
}
-bool Inliner::runOnSCC(const std::vector<CallGraphNode*> &SCC) {
+/// InlineHistoryIncludes - Return true if the specified inline history ID
+/// indicates an inline history that includes the specified function.
+static bool InlineHistoryIncludes(Function *F, int InlineHistoryID,
+ const SmallVectorImpl<std::pair<Function*, int> > &InlineHistory) {
+ while (InlineHistoryID != -1) {
+ assert(unsigned(InlineHistoryID) < InlineHistory.size() &&
+ "Invalid inline history ID");
+ if (InlineHistory[InlineHistoryID].first == F)
+ return true;
+ InlineHistoryID = InlineHistory[InlineHistoryID].second;
+ }
+ return false;
+}
+
+bool Inliner::runOnSCC(CallGraphSCC &SCC) {
CallGraph &CG = getAnalysis<CallGraph>();
+ const DataLayout *TD = getAnalysisIfAvailable<DataLayout>();
+ const TargetLibraryInfo *TLI = getAnalysisIfAvailable<TargetLibraryInfo>();
- std::set<Function*> SCCFunctions;
- DOUT << "Inliner visiting SCC:";
- for (unsigned i = 0, e = SCC.size(); i != e; ++i) {
- Function *F = SCC[i]->getFunction();
+ SmallPtrSet<Function*, 8> SCCFunctions;
+ DEBUG(dbgs() << "Inliner visiting SCC:");
+ for (CallGraphSCC::iterator I = SCC.begin(), E = SCC.end(); I != E; ++I) {
+ Function *F = (*I)->getFunction();
if (F) SCCFunctions.insert(F);
- DOUT << " " << (F ? F->getName() : "INDIRECTNODE");
+ DEBUG(dbgs() << " " << (F ? F->getName() : "INDIRECTNODE"));
}
// Scan through and identify all call sites ahead of time so that we only
// inline call sites in the original functions, not call sites that result
// from inlining other functions.
- std::vector<CallSite> CallSites;
-
- for (unsigned i = 0, e = SCC.size(); i != e; ++i)
- if (Function *F = SCC[i]->getFunction())
- for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB)
- for (BasicBlock::iterator I = BB->begin(); I != BB->end(); ++I) {
- CallSite CS = CallSite::get(I);
- if (CS.getInstruction() && (!CS.getCalledFunction() ||
- !CS.getCalledFunction()->isDeclaration()))
- CallSites.push_back(CS);
- }
+ SmallVector<std::pair<CallSite, int>, 16> CallSites;
+
+ // When inlining a callee produces new call sites, we want to keep track of
+ // the fact that they were inlined from the callee. This allows us to avoid
+ // infinite inlining in some obscure cases. To represent this, we use an
+ // index into the InlineHistory vector.
+ SmallVector<std::pair<Function*, int>, 8> InlineHistory;
+
+ for (CallGraphSCC::iterator I = SCC.begin(), E = SCC.end(); I != E; ++I) {
+ Function *F = (*I)->getFunction();
+ if (!F) continue;
+
+ 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(cast<Value>(I));
+ // If this isn't a call, or it is a call to an intrinsic, it can
+ // never be inlined.
+ if (!CS || isa<IntrinsicInst>(I))
+ continue;
+
+ // If this is a direct call to an external function, we can never inline
+ // it. If it is an indirect call, inlining may resolve it to be a
+ // direct call, so we keep it.
+ if (CS.getCalledFunction() && CS.getCalledFunction()->isDeclaration())
+ continue;
+
+ CallSites.push_back(std::make_pair(CS, -1));
+ }
+ }
- DOUT << ": " << CallSites.size() << " call sites.\n";
+ DEBUG(dbgs() << ": " << CallSites.size() << " call sites.\n");
+ // If there are no calls in this function, exit early.
+ if (CallSites.empty())
+ return false;
+
// Now that we have all of the call sites, move the ones to functions in the
// current SCC to the end of the list.
unsigned FirstCallInSCC = CallSites.size();
for (unsigned i = 0; i < FirstCallInSCC; ++i)
- if (Function *F = CallSites[i].getCalledFunction())
+ if (Function *F = CallSites[i].first.getCalledFunction())
if (SCCFunctions.count(F))
std::swap(CallSites[i--], CallSites[--FirstCallInSCC]);
+
+ InlinedArrayAllocasTy InlinedArrayAllocas;
+ InlineFunctionInfo InlineInfo(&CG, TD);
+
// Now that we have all of the call sites, loop over them and inline them if
// it looks profitable to do so.
bool Changed = false;
LocalChange = false;
// Iterate over the outer loop because inlining functions can cause indirect
// calls to become direct calls.
- for (unsigned CSi = 0; CSi != CallSites.size(); ++CSi)
- if (Function *Callee = CallSites[CSi].getCalledFunction()) {
- // Calls to external functions are never inlinable.
- if (Callee->isDeclaration() ||
- CallSites[CSi].getInstruction()->getParent()->getParent() ==Callee){
- if (SCC.size() == 1) {
- std::swap(CallSites[CSi], CallSites.back());
- CallSites.pop_back();
- } else {
- // Keep the 'in SCC / not in SCC' boundary correct.
- CallSites.erase(CallSites.begin()+CSi);
- }
- --CSi;
- continue;
- }
+ for (unsigned CSi = 0; CSi != CallSites.size(); ++CSi) {
+ CallSite CS = CallSites[CSi].first;
+
+ Function *Caller = CS.getCaller();
+ Function *Callee = CS.getCalledFunction();
+ // If this call site is dead and it is to a readonly function, we should
+ // just delete the call instead of trying to inline it, regardless of
+ // size. This happens because IPSCCP propagates the result out of the
+ // call and then we're left with the dead call.
+ if (isInstructionTriviallyDead(CS.getInstruction(), TLI)) {
+ DEBUG(dbgs() << " -> Deleting dead call: "
+ << *CS.getInstruction() << "\n");
+ // Update the call graph by deleting the edge from Callee to Caller.
+ CG[Caller]->removeCallEdgeFor(CS);
+ CS.getInstruction()->eraseFromParent();
+ ++NumCallsDeleted;
+ } else {
+ // We can only inline direct calls to non-declarations.
+ if (Callee == 0 || Callee->isDeclaration()) continue;
+
+ // If this call site was obtained by inlining another function, verify
+ // that the include path for the function did not include the callee
+ // itself. If so, we'd be recursively inlining the same function,
+ // which would provide the same callsites, which would cause us to
+ // infinitely inline.
+ int InlineHistoryID = CallSites[CSi].second;
+ if (InlineHistoryID != -1 &&
+ InlineHistoryIncludes(Callee, InlineHistoryID, InlineHistory))
+ continue;
+
+
// If the policy determines that we should inline this function,
// try to do so.
- CallSite CS = CallSites[CSi];
- int InlineCost = getInlineCost(CS);
- float FudgeFactor = getInlineFudgeFactor(CS);
-
- int CurrentThreshold = InlineThreshold;
- Function *Fn = CS.getCaller();
- if (Fn && !Fn->isDeclaration() && Fn->hasNote(FN_NOTE_OptimizeForSize)
- && InlineThreshold != 50) {
- CurrentThreshold = 50;
- }
+ if (!shouldInline(CS))
+ continue;
+
+ // Attempt to inline the function.
+ if (!InlineCallIfPossible(CS, InlineInfo, InlinedArrayAllocas,
+ InlineHistoryID, InsertLifetime))
+ continue;
+ ++NumInlined;
- if (InlineCost >= (int)(CurrentThreshold * FudgeFactor)) {
- DOUT << " NOT Inlining: cost=" << InlineCost
- << ", Call: " << *CS.getInstruction();
- } else {
- DOUT << " Inlining: cost=" << InlineCost
- << ", Call: " << *CS.getInstruction();
-
- // Attempt to inline the function...
- if (InlineCallIfPossible(CS, CG, SCCFunctions,
- getAnalysis<TargetData>())) {
- // Remove this call site from the list. If possible, use
- // swap/pop_back for efficiency, but do not use it if doing so would
- // move a call site to a function in this SCC before the
- // 'FirstCallInSCC' barrier.
- if (SCC.size() == 1) {
- std::swap(CallSites[CSi], CallSites.back());
- CallSites.pop_back();
- } else {
- CallSites.erase(CallSites.begin()+CSi);
- }
- --CSi;
-
- ++NumInlined;
- Changed = true;
- LocalChange = true;
+ // If inlining this function gave us any new call sites, throw them
+ // onto our worklist to process. They are useful inline candidates.
+ if (!InlineInfo.InlinedCalls.empty()) {
+ // Create a new inline history entry for this, so that we remember
+ // that these new callsites came about due to inlining Callee.
+ int NewHistoryID = InlineHistory.size();
+ InlineHistory.push_back(std::make_pair(Callee, InlineHistoryID));
+
+ for (unsigned i = 0, e = InlineInfo.InlinedCalls.size();
+ i != e; ++i) {
+ Value *Ptr = InlineInfo.InlinedCalls[i];
+ CallSites.push_back(std::make_pair(CallSite(Ptr), NewHistoryID));
}
}
}
+
+ // If we inlined or deleted the last possible call site to the function,
+ // delete the function body now.
+ if (Callee && Callee->use_empty() && Callee->hasLocalLinkage() &&
+ // TODO: Can remove if in SCC now.
+ !SCCFunctions.count(Callee) &&
+
+ // The function may be apparently dead, but if there are indirect
+ // callgraph references to the node, we cannot delete it yet, this
+ // could invalidate the CGSCC iterator.
+ CG[Callee]->getNumReferences() == 0) {
+ DEBUG(dbgs() << " -> Deleting dead function: "
+ << Callee->getName() << "\n");
+ CallGraphNode *CalleeNode = CG[Callee];
+
+ // Remove any call graph edges from the callee to its callees.
+ CalleeNode->removeAllCalledFunctions();
+
+ // Removing the node for callee from the call graph and delete it.
+ delete CG.removeFunctionFromModule(CalleeNode);
+ ++NumDeleted;
+ }
+
+ // Remove this call site from the list. If possible, use
+ // swap/pop_back for efficiency, but do not use it if doing so would
+ // move a call site to a function in this SCC before the
+ // 'FirstCallInSCC' barrier.
+ if (SCC.isSingular()) {
+ CallSites[CSi] = CallSites.back();
+ CallSites.pop_back();
+ } else {
+ CallSites.erase(CallSites.begin()+CSi);
+ }
+ --CSi;
+
+ Changed = true;
+ LocalChange = true;
+ }
} while (LocalChange);
return Changed;
// doFinalization - Remove now-dead linkonce functions at the end of
// processing to avoid breaking the SCC traversal.
bool Inliner::doFinalization(CallGraph &CG) {
- std::set<CallGraphNode*> FunctionsToRemove;
+ return removeDeadFunctions(CG);
+}
+
+/// removeDeadFunctions - Remove dead functions that are not included in
+/// DNR (Do Not Remove) list.
+bool Inliner::removeDeadFunctions(CallGraph &CG, bool AlwaysInlineOnly) {
+ SmallVector<CallGraphNode*, 16> FunctionsToRemove;
// Scan for all of the functions, looking for ones that should now be removed
// from the program. Insert the dead ones in the FunctionsToRemove set.
for (CallGraph::iterator I = CG.begin(), E = CG.end(); I != E; ++I) {
CallGraphNode *CGN = I->second;
- if (Function *F = CGN ? CGN->getFunction() : 0) {
- // If the only remaining users of the function are dead constants, remove
- // them.
- F->removeDeadConstantUsers();
+ Function *F = CGN->getFunction();
+ if (!F || F->isDeclaration())
+ continue;
- if ((F->hasLinkOnceLinkage() || F->hasInternalLinkage()) &&
- F->use_empty()) {
+ // Handle the case when this function is called and we only want to care
+ // about always-inline functions. This is a bit of a hack to share code
+ // between here and the InlineAlways pass.
+ if (AlwaysInlineOnly &&
+ !F->getFnAttributes().hasAttribute(Attributes::AlwaysInline))
+ continue;
- // Remove any call graph edges from the function to its callees.
- CGN->removeAllCalledFunctions();
+ // If the only remaining users of the function are dead constants, remove
+ // them.
+ F->removeDeadConstantUsers();
- // Remove any edges from the external node to the function's call graph
- // node. These edges might have been made irrelegant due to
- // optimization of the program.
- CG.getExternalCallingNode()->removeAnyCallEdgeTo(CGN);
+ if (!F->isDefTriviallyDead())
+ continue;
+
+ // Remove any call graph edges from the function to its callees.
+ CGN->removeAllCalledFunctions();
- // Removing the node for callee from the call graph and delete it.
- FunctionsToRemove.insert(CGN);
- }
- }
+ // Remove any edges from the external node to the function's call graph
+ // node. These edges might have been made irrelegant due to
+ // optimization of the program.
+ CG.getExternalCallingNode()->removeAnyCallEdgeTo(CGN);
+
+ // Removing the node for callee from the call graph and delete it.
+ FunctionsToRemove.push_back(CGN);
}
+ if (FunctionsToRemove.empty())
+ return false;
// Now that we know which functions to delete, do so. We didn't want to do
// this inline, because that would invalidate our CallGraph::iterator
// objects. :(
- bool Changed = false;
- for (std::set<CallGraphNode*>::iterator I = FunctionsToRemove.begin(),
- E = FunctionsToRemove.end(); I != E; ++I) {
+ //
+ // Note that it doesn't matter that we are iterating over a non-stable order
+ // here to do this, it doesn't matter which order the functions are deleted
+ // in.
+ array_pod_sort(FunctionsToRemove.begin(), FunctionsToRemove.end());
+ FunctionsToRemove.erase(std::unique(FunctionsToRemove.begin(),
+ FunctionsToRemove.end()),
+ FunctionsToRemove.end());
+ for (SmallVectorImpl<CallGraphNode *>::iterator I = FunctionsToRemove.begin(),
+ E = FunctionsToRemove.end();
+ I != E; ++I) {
delete CG.removeFunctionFromModule(*I);
++NumDeleted;
- Changed = true;
}
-
- return Changed;
+ return true;
}
projects / oota-llvm.git / blobdiff