mirror of
				https://github.com/c64scene-ar/llvm-6502.git
				synced 2025-10-31 08:16:47 +00:00 
			
		
		
		
	SSPStrong applies a heuristic to insert stack protectors in these situations: * A Protector is required for functions which contain an array, regardless of type or length. * A Protector is required for functions which contain a structure/union which contains an array, regardless of type or length. Note, there is no limit to the depth of nesting. * A protector is required when the address of a local variable (i.e., stack based variable) is exposed. (E.g., such as through a local whose address is taken as part of the RHS of an assignment or a local whose address is taken as part of a function argument.) This patch implements the SSPString attribute to be equivalent to SSPRequired. This will change in a subsequent patch. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@173230 91177308-0d34-0410-b5e6-96231b3b80d8
		
			
				
	
	
		
			614 lines
		
	
	
		
			26 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			614 lines
		
	
	
		
			26 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
| //===- Inliner.cpp - Code common to all inliners --------------------------===//
 | |
| //
 | |
| //                     The LLVM Compiler Infrastructure
 | |
| //
 | |
| // This file is distributed under the University of Illinois Open Source
 | |
| // License. See LICENSE.TXT for details.
 | |
| //
 | |
| //===----------------------------------------------------------------------===//
 | |
| //
 | |
| // This file implements the mechanics required to implement inlining without
 | |
| // missing any calls and updating the call graph.  The decisions of which calls
 | |
| // are profitable to inline are implemented elsewhere.
 | |
| //
 | |
| //===----------------------------------------------------------------------===//
 | |
| 
 | |
| #define DEBUG_TYPE "inline"
 | |
| #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/IR/DataLayout.h"
 | |
| #include "llvm/IR/Instructions.h"
 | |
| #include "llvm/IR/IntrinsicInst.h"
 | |
| #include "llvm/IR/Module.h"
 | |
| #include "llvm/Support/CallSite.h"
 | |
| #include "llvm/Support/CommandLine.h"
 | |
| #include "llvm/Support/Debug.h"
 | |
| #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(225), cl::ZeroOrMore,
 | |
|         cl::desc("Control the amount of inlining to perform (default = 225)"));
 | |
| 
 | |
| 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(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 &AU) const {
 | |
|   CallGraphSCCPass::getAnalysisUsage(AU);
 | |
| }
 | |
| 
 | |
| 
 | |
| typedef DenseMap<ArrayType*, std::vector<AllocaInst*> >
 | |
| InlinedArrayAllocasTy;
 | |
| 
 | |
| /// \brief If the inlined function had a higher stack protection level than the
 | |
| /// calling function, then bump up the caller's stack protection level.
 | |
| static void AdjustCallerSSPLevel(Function *Caller, Function *Callee) {
 | |
|   // If upgrading the SSP attribute, clear out the old SSP Attributes first.
 | |
|   // Having multiple SSP attributes doesn't actually hurt, but it adds useless
 | |
|   // clutter to the IR.
 | |
|   AttrBuilder B;
 | |
|   B.addAttribute(Attribute::StackProtect)
 | |
|     .addAttribute(Attribute::StackProtectStrong);
 | |
|   AttributeSet OldSSPAttr = AttributeSet::get(Caller->getContext(),
 | |
|                                               AttributeSet::FunctionIndex,
 | |
|                                               B);
 | |
|   AttributeSet CallerAttr = Caller->getAttributes(),
 | |
|                CalleeAttr = Callee->getAttributes();
 | |
| 
 | |
|   if (CalleeAttr.hasAttribute(AttributeSet::FunctionIndex,
 | |
|                               Attribute::StackProtectReq)) {
 | |
|     Caller->removeAttributes(AttributeSet::FunctionIndex, OldSSPAttr);
 | |
|     Caller->addFnAttr(Attribute::StackProtectReq);
 | |
|   } else if (CalleeAttr.hasAttribute(AttributeSet::FunctionIndex,
 | |
|                                      Attribute::StackProtectStrong) &&
 | |
|              !CallerAttr.hasAttribute(AttributeSet::FunctionIndex,
 | |
|                                       Attribute::StackProtectReq)) {
 | |
|     Caller->removeAttributes(AttributeSet::FunctionIndex, OldSSPAttr);
 | |
|     Caller->addFnAttr(Attribute::StackProtectStrong);
 | |
|   } else if (CalleeAttr.hasAttribute(AttributeSet::FunctionIndex,
 | |
|                                      Attribute::StackProtect) &&
 | |
|            !CallerAttr.hasAttribute(AttributeSet::FunctionIndex,
 | |
|                                     Attribute::StackProtectReq) &&
 | |
|            !CallerAttr.hasAttribute(AttributeSet::FunctionIndex,
 | |
|                                     Attribute::StackProtectStrong))
 | |
|     Caller->addFnAttr(Attribute::StackProtect);
 | |
| }
 | |
| 
 | |
| /// 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();
 | |
|   Function *Caller = CS.getCaller();
 | |
| 
 | |
|   // Try to inline the function.  Get the list of static allocas that were
 | |
|   // inlined.
 | |
|   if (!InlineFunction(CS, IFI, InsertLifetime))
 | |
|     return false;
 | |
| 
 | |
|   AdjustCallerSSPLevel(Caller, Callee);
 | |
| 
 | |
|   // 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->getAttributes().hasAttribute(AttributeSet::FunctionIndex,
 | |
|                                          Attribute::OptimizeForSize);
 | |
|   if (!(InlineLimit.getNumOccurrences() > 0) && OptSize &&
 | |
|       OptSizeThreshold < thres)
 | |
|     thres = OptSizeThreshold;
 | |
| 
 | |
|   // Listen to the inlinehint attribute when it would increase the threshold
 | |
|   // and the caller does not need to minimize its size.
 | |
|   Function *Callee = CS.getCalledFunction();
 | |
|   bool InlineHint = Callee && !Callee->isDeclaration() &&
 | |
|     Callee->getAttributes().hasAttribute(AttributeSet::FunctionIndex,
 | |
|                                          Attribute::InlineHint);
 | |
|   if (InlineHint && HintThreshold > thres
 | |
|       && !Caller->getAttributes().hasAttribute(AttributeSet::FunctionIndex,
 | |
|                                                Attribute::MinSize))
 | |
|     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;
 | |
| }
 | |
| 
 | |
| /// 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>();
 | |
| 
 | |
|   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);
 | |
|     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.
 | |
|   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));
 | |
|       }
 | |
|   }
 | |
| 
 | |
|   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].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;
 | |
|   bool LocalChange;
 | |
|   do {
 | |
|     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) {
 | |
|       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.
 | |
|         if (!shouldInline(CS))
 | |
|           continue;
 | |
| 
 | |
|         // Attempt to inline the function.
 | |
|         if (!InlineCallIfPossible(CS, InlineInfo, InlinedArrayAllocas,
 | |
|                                   InlineHistoryID, InsertLifetime))
 | |
|           continue;
 | |
|         ++NumInlined;
 | |
|         
 | |
|         // 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) {
 | |
|   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;
 | |
|     Function *F = CGN->getFunction();
 | |
|     if (!F || F->isDeclaration())
 | |
|       continue;
 | |
| 
 | |
|     // 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->getAttributes().hasAttribute(AttributeSet::FunctionIndex,
 | |
|                                          Attribute::AlwaysInline))
 | |
|       continue;
 | |
| 
 | |
|     // If the only remaining users of the function are dead constants, remove
 | |
|     // them.
 | |
|     F->removeDeadConstantUsers();
 | |
| 
 | |
|     if (!F->isDefTriviallyDead())
 | |
|       continue;
 | |
|     
 | |
|     // Remove any call graph edges from the function to its callees.
 | |
|     CGN->removeAllCalledFunctions();
 | |
| 
 | |
|     // 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. :(
 | |
|   //
 | |
|   // 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;
 | |
|   }
 | |
|   return true;
 | |
| }
 |