| //===- Inliner.cpp - Code common to all inliners --------------------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // 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. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "llvm/Transforms/IPO/Inliner.h" |
| #include "llvm/ADT/PriorityWorklist.h" |
| #include "llvm/ADT/STLExtras.h" |
| #include "llvm/ADT/ScopeExit.h" |
| #include "llvm/ADT/SetVector.h" |
| #include "llvm/ADT/SmallPtrSet.h" |
| #include "llvm/ADT/SmallVector.h" |
| #include "llvm/ADT/Statistic.h" |
| #include "llvm/ADT/StringExtras.h" |
| #include "llvm/ADT/StringRef.h" |
| #include "llvm/Analysis/AssumptionCache.h" |
| #include "llvm/Analysis/BasicAliasAnalysis.h" |
| #include "llvm/Analysis/BlockFrequencyInfo.h" |
| #include "llvm/Analysis/CGSCCPassManager.h" |
| #include "llvm/Analysis/InlineAdvisor.h" |
| #include "llvm/Analysis/InlineCost.h" |
| #include "llvm/Analysis/LazyCallGraph.h" |
| #include "llvm/Analysis/OptimizationRemarkEmitter.h" |
| #include "llvm/Analysis/ProfileSummaryInfo.h" |
| #include "llvm/Analysis/ReplayInlineAdvisor.h" |
| #include "llvm/Analysis/TargetLibraryInfo.h" |
| #include "llvm/Analysis/Utils/ImportedFunctionsInliningStatistics.h" |
| #include "llvm/IR/Attributes.h" |
| #include "llvm/IR/BasicBlock.h" |
| #include "llvm/IR/DebugLoc.h" |
| #include "llvm/IR/DerivedTypes.h" |
| #include "llvm/IR/DiagnosticInfo.h" |
| #include "llvm/IR/Function.h" |
| #include "llvm/IR/InstIterator.h" |
| #include "llvm/IR/Instruction.h" |
| #include "llvm/IR/Instructions.h" |
| #include "llvm/IR/IntrinsicInst.h" |
| #include "llvm/IR/Metadata.h" |
| #include "llvm/IR/Module.h" |
| #include "llvm/IR/PassManager.h" |
| #include "llvm/IR/User.h" |
| #include "llvm/IR/Value.h" |
| #include "llvm/Pass.h" |
| #include "llvm/Support/Casting.h" |
| #include "llvm/Support/CommandLine.h" |
| #include "llvm/Support/Debug.h" |
| #include "llvm/Support/raw_ostream.h" |
| #include "llvm/Transforms/Utils/CallPromotionUtils.h" |
| #include "llvm/Transforms/Utils/Cloning.h" |
| #include "llvm/Transforms/Utils/Local.h" |
| #include "llvm/Transforms/Utils/ModuleUtils.h" |
| #include <algorithm> |
| #include <cassert> |
| #include <functional> |
| #include <utility> |
| |
| using namespace llvm; |
| |
| #define DEBUG_TYPE "inline" |
| |
| STATISTIC(NumInlined, "Number of functions inlined"); |
| STATISTIC(NumDeleted, "Number of functions deleted because all callers found"); |
| |
| static cl::opt<int> IntraSCCCostMultiplier( |
| "intra-scc-cost-multiplier", cl::init(2), cl::Hidden, |
| cl::desc( |
| "Cost multiplier to multiply onto inlined call sites where the " |
| "new call was previously an intra-SCC call (not relevant when the " |
| "original call was already intra-SCC). This can accumulate over " |
| "multiple inlinings (e.g. if a call site already had a cost " |
| "multiplier and one of its inlined calls was also subject to " |
| "this, the inlined call would have the original multiplier " |
| "multiplied by intra-scc-cost-multiplier). This is to prevent tons of " |
| "inlining through a child SCC which can cause terrible compile times")); |
| |
| /// A flag for test, so we can print the content of the advisor when running it |
| /// as part of the default (e.g. -O3) pipeline. |
| static cl::opt<bool> KeepAdvisorForPrinting("keep-inline-advisor-for-printing", |
| cl::init(false), cl::Hidden); |
| |
| /// Allows printing the contents of the advisor after each SCC inliner pass. |
| static cl::opt<bool> |
| EnablePostSCCAdvisorPrinting("enable-scc-inline-advisor-printing", |
| cl::init(false), cl::Hidden); |
| |
| |
| static cl::opt<std::string> CGSCCInlineReplayFile( |
| "cgscc-inline-replay", cl::init(""), cl::value_desc("filename"), |
| cl::desc( |
| "Optimization remarks file containing inline remarks to be replayed " |
| "by cgscc inlining."), |
| cl::Hidden); |
| |
| static cl::opt<ReplayInlinerSettings::Scope> CGSCCInlineReplayScope( |
| "cgscc-inline-replay-scope", |
| cl::init(ReplayInlinerSettings::Scope::Function), |
| cl::values(clEnumValN(ReplayInlinerSettings::Scope::Function, "Function", |
| "Replay on functions that have remarks associated " |
| "with them (default)"), |
| clEnumValN(ReplayInlinerSettings::Scope::Module, "Module", |
| "Replay on the entire module")), |
| cl::desc("Whether inline replay should be applied to the entire " |
| "Module or just the Functions (default) that are present as " |
| "callers in remarks during cgscc inlining."), |
| cl::Hidden); |
| |
| static cl::opt<ReplayInlinerSettings::Fallback> CGSCCInlineReplayFallback( |
| "cgscc-inline-replay-fallback", |
| cl::init(ReplayInlinerSettings::Fallback::Original), |
| cl::values( |
| clEnumValN( |
| ReplayInlinerSettings::Fallback::Original, "Original", |
| "All decisions not in replay send to original advisor (default)"), |
| clEnumValN(ReplayInlinerSettings::Fallback::AlwaysInline, |
| "AlwaysInline", "All decisions not in replay are inlined"), |
| clEnumValN(ReplayInlinerSettings::Fallback::NeverInline, "NeverInline", |
| "All decisions not in replay are not inlined")), |
| cl::desc( |
| "How cgscc inline replay treats sites that don't come from the replay. " |
| "Original: defers to original advisor, AlwaysInline: inline all sites " |
| "not in replay, NeverInline: inline no sites not in replay"), |
| cl::Hidden); |
| |
| static cl::opt<CallSiteFormat::Format> CGSCCInlineReplayFormat( |
| "cgscc-inline-replay-format", |
| cl::init(CallSiteFormat::Format::LineColumnDiscriminator), |
| cl::values( |
| clEnumValN(CallSiteFormat::Format::Line, "Line", "<Line Number>"), |
| clEnumValN(CallSiteFormat::Format::LineColumn, "LineColumn", |
| "<Line Number>:<Column Number>"), |
| clEnumValN(CallSiteFormat::Format::LineDiscriminator, |
| "LineDiscriminator", "<Line Number>.<Discriminator>"), |
| clEnumValN(CallSiteFormat::Format::LineColumnDiscriminator, |
| "LineColumnDiscriminator", |
| "<Line Number>:<Column Number>.<Discriminator> (default)")), |
| cl::desc("How cgscc inline replay file is formatted"), cl::Hidden); |
| |
| /// 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; |
| } |
| |
| InlineAdvisor & |
| InlinerPass::getAdvisor(const ModuleAnalysisManagerCGSCCProxy::Result &MAM, |
| FunctionAnalysisManager &FAM, Module &M) { |
| if (OwnedAdvisor) |
| return *OwnedAdvisor; |
| |
| auto *IAA = MAM.getCachedResult<InlineAdvisorAnalysis>(M); |
| if (!IAA) { |
| // It should still be possible to run the inliner as a stand-alone SCC pass, |
| // for test scenarios. In that case, we default to the |
| // DefaultInlineAdvisor, which doesn't need to keep state between SCC pass |
| // runs. It also uses just the default InlineParams. |
| // In this case, we need to use the provided FAM, which is valid for the |
| // duration of the inliner pass, and thus the lifetime of the owned advisor. |
| // The one we would get from the MAM can be invalidated as a result of the |
| // inliner's activity. |
| OwnedAdvisor = std::make_unique<DefaultInlineAdvisor>( |
| M, FAM, getInlineParams(), |
| InlineContext{LTOPhase, InlinePass::CGSCCInliner}); |
| |
| if (!CGSCCInlineReplayFile.empty()) |
| OwnedAdvisor = getReplayInlineAdvisor( |
| M, FAM, M.getContext(), std::move(OwnedAdvisor), |
| ReplayInlinerSettings{CGSCCInlineReplayFile, |
| CGSCCInlineReplayScope, |
| CGSCCInlineReplayFallback, |
| {CGSCCInlineReplayFormat}}, |
| /*EmitRemarks=*/true, |
| InlineContext{LTOPhase, InlinePass::ReplayCGSCCInliner}); |
| |
| return *OwnedAdvisor; |
| } |
| assert(IAA->getAdvisor() && |
| "Expected a present InlineAdvisorAnalysis also have an " |
| "InlineAdvisor initialized"); |
| return *IAA->getAdvisor(); |
| } |
| |
| void makeFunctionBodyUnreachable(Function &F) { |
| F.dropAllReferences(); |
| for (BasicBlock &BB : make_early_inc_range(F)) |
| BB.eraseFromParent(); |
| BasicBlock *BB = BasicBlock::Create(F.getContext(), "", &F); |
| new UnreachableInst(F.getContext(), BB); |
| } |
| |
| PreservedAnalyses InlinerPass::run(LazyCallGraph::SCC &InitialC, |
| CGSCCAnalysisManager &AM, LazyCallGraph &CG, |
| CGSCCUpdateResult &UR) { |
| const auto &MAMProxy = |
| AM.getResult<ModuleAnalysisManagerCGSCCProxy>(InitialC, CG); |
| bool Changed = false; |
| |
| assert(InitialC.size() > 0 && "Cannot handle an empty SCC!"); |
| Module &M = *InitialC.begin()->getFunction().getParent(); |
| ProfileSummaryInfo *PSI = MAMProxy.getCachedResult<ProfileSummaryAnalysis>(M); |
| |
| FunctionAnalysisManager &FAM = |
| AM.getResult<FunctionAnalysisManagerCGSCCProxy>(InitialC, CG) |
| .getManager(); |
| |
| InlineAdvisor &Advisor = getAdvisor(MAMProxy, FAM, M); |
| Advisor.onPassEntry(&InitialC); |
| |
| // We use a single common worklist for calls across the entire SCC. We |
| // process these in-order and append new calls introduced during inlining to |
| // the end. The PriorityInlineOrder is optional here, in which the smaller |
| // callee would have a higher priority to inline. |
| // |
| // Note that this particular order of processing is actually critical to |
| // avoid very bad behaviors. Consider *highly connected* call graphs where |
| // each function contains a small amount of code and a couple of calls to |
| // other functions. Because the LLVM inliner is fundamentally a bottom-up |
| // inliner, it can handle gracefully the fact that these all appear to be |
| // reasonable inlining candidates as it will flatten things until they become |
| // too big to inline, and then move on and flatten another batch. |
| // |
| // However, when processing call edges *within* an SCC we cannot rely on this |
| // bottom-up behavior. As a consequence, with heavily connected *SCCs* of |
| // functions we can end up incrementally inlining N calls into each of |
| // N functions because each incremental inlining decision looks good and we |
| // don't have a topological ordering to prevent explosions. |
| // |
| // To compensate for this, we don't process transitive edges made immediate |
| // by inlining until we've done one pass of inlining across the entire SCC. |
| // Large, highly connected SCCs still lead to some amount of code bloat in |
| // this model, but it is uniformly spread across all the functions in the SCC |
| // and eventually they all become too large to inline, rather than |
| // incrementally maknig a single function grow in a super linear fashion. |
| SmallVector<std::pair<CallBase *, int>, 16> Calls; |
| |
| // Populate the initial list of calls in this SCC. |
| for (auto &N : InitialC) { |
| auto &ORE = |
| FAM.getResult<OptimizationRemarkEmitterAnalysis>(N.getFunction()); |
| // We want to generally process call sites top-down in order for |
| // simplifications stemming from replacing the call with the returned value |
| // after inlining to be visible to subsequent inlining decisions. |
| // FIXME: Using instructions sequence is a really bad way to do this. |
| // Instead we should do an actual RPO walk of the function body. |
| for (Instruction &I : instructions(N.getFunction())) |
| if (auto *CB = dyn_cast<CallBase>(&I)) |
| if (Function *Callee = CB->getCalledFunction()) { |
| if (!Callee->isDeclaration()) |
| Calls.push_back({CB, -1}); |
| else if (!isa<IntrinsicInst>(I)) { |
| using namespace ore; |
| setInlineRemark(*CB, "unavailable definition"); |
| ORE.emit([&]() { |
| return OptimizationRemarkMissed(DEBUG_TYPE, "NoDefinition", &I) |
| << NV("Callee", Callee) << " will not be inlined into " |
| << NV("Caller", CB->getCaller()) |
| << " because its definition is unavailable" |
| << setIsVerbose(); |
| }); |
| } |
| } |
| } |
| |
| // Capture updatable variable for the current SCC. |
| auto *C = &InitialC; |
| |
| auto AdvisorOnExit = make_scope_exit([&] { Advisor.onPassExit(C); }); |
| |
| if (Calls.empty()) |
| return PreservedAnalyses::all(); |
| |
| // 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>, 16> InlineHistory; |
| |
| // Track a set vector of inlined callees so that we can augment the caller |
| // with all of their edges in the call graph before pruning out the ones that |
| // got simplified away. |
| SmallSetVector<Function *, 4> InlinedCallees; |
| |
| // Track the dead functions to delete once finished with inlining calls. We |
| // defer deleting these to make it easier to handle the call graph updates. |
| SmallVector<Function *, 4> DeadFunctions; |
| |
| // Track potentially dead non-local functions with comdats to see if they can |
| // be deleted as a batch after inlining. |
| SmallVector<Function *, 4> DeadFunctionsInComdats; |
| |
| // Loop forward over all of the calls. Note that we cannot cache the size as |
| // inlining can introduce new calls that need to be processed. |
| for (int I = 0; I < (int)Calls.size(); ++I) { |
| // We expect the calls to typically be batched with sequences of calls that |
| // have the same caller, so we first set up some shared infrastructure for |
| // this caller. We also do any pruning we can at this layer on the caller |
| // alone. |
| Function &F = *Calls[I].first->getCaller(); |
| LazyCallGraph::Node &N = *CG.lookup(F); |
| if (CG.lookupSCC(N) != C) |
| continue; |
| |
| LLVM_DEBUG(dbgs() << "Inlining calls in: " << F.getName() << "\n" |
| << " Function size: " << F.getInstructionCount() |
| << "\n"); |
| |
| auto GetAssumptionCache = [&](Function &F) -> AssumptionCache & { |
| return FAM.getResult<AssumptionAnalysis>(F); |
| }; |
| |
| // Now process as many calls as we have within this caller in the sequence. |
| // We bail out as soon as the caller has to change so we can update the |
| // call graph and prepare the context of that new caller. |
| bool DidInline = false; |
| for (; I < (int)Calls.size() && Calls[I].first->getCaller() == &F; ++I) { |
| auto &P = Calls[I]; |
| CallBase *CB = P.first; |
| const int InlineHistoryID = P.second; |
| Function &Callee = *CB->getCalledFunction(); |
| |
| if (InlineHistoryID != -1 && |
| inlineHistoryIncludes(&Callee, InlineHistoryID, InlineHistory)) { |
| LLVM_DEBUG(dbgs() << "Skipping inlining due to history: " << F.getName() |
| << " -> " << Callee.getName() << "\n"); |
| setInlineRemark(*CB, "recursive"); |
| // Set noinline so that we don't forget this decision across CGSCC |
| // iterations. |
| CB->setIsNoInline(); |
| continue; |
| } |
| |
| // Check if this inlining may repeat breaking an SCC apart that has |
| // already been split once before. In that case, inlining here may |
| // trigger infinite inlining, much like is prevented within the inliner |
| // itself by the InlineHistory above, but spread across CGSCC iterations |
| // and thus hidden from the full inline history. |
| LazyCallGraph::SCC *CalleeSCC = CG.lookupSCC(*CG.lookup(Callee)); |
| if (CalleeSCC == C && UR.InlinedInternalEdges.count({&N, C})) { |
| LLVM_DEBUG(dbgs() << "Skipping inlining internal SCC edge from a node " |
| "previously split out of this SCC by inlining: " |
| << F.getName() << " -> " << Callee.getName() << "\n"); |
| setInlineRemark(*CB, "recursive SCC split"); |
| continue; |
| } |
| |
| std::unique_ptr<InlineAdvice> Advice = |
| Advisor.getAdvice(*CB, OnlyMandatory); |
| |
| // Check whether we want to inline this callsite. |
| if (!Advice) |
| continue; |
| |
| if (!Advice->isInliningRecommended()) { |
| Advice->recordUnattemptedInlining(); |
| continue; |
| } |
| |
| int CBCostMult = |
| getStringFnAttrAsInt( |
| *CB, InlineConstants::FunctionInlineCostMultiplierAttributeName) |
| .value_or(1); |
| |
| // Setup the data structure used to plumb customization into the |
| // `InlineFunction` routine. |
| InlineFunctionInfo IFI( |
| GetAssumptionCache, PSI, |
| &FAM.getResult<BlockFrequencyAnalysis>(*(CB->getCaller())), |
| &FAM.getResult<BlockFrequencyAnalysis>(Callee)); |
| |
| InlineResult IR = |
| InlineFunction(*CB, IFI, /*MergeAttributes=*/true, |
| &FAM.getResult<AAManager>(*CB->getCaller())); |
| if (!IR.isSuccess()) { |
| Advice->recordUnsuccessfulInlining(IR); |
| continue; |
| } |
| |
| DidInline = true; |
| InlinedCallees.insert(&Callee); |
| ++NumInlined; |
| |
| LLVM_DEBUG(dbgs() << " Size after inlining: " |
| << F.getInstructionCount() << "\n"); |
| |
| // Add any new callsites to defined functions to the worklist. |
| if (!IFI.InlinedCallSites.empty()) { |
| int NewHistoryID = InlineHistory.size(); |
| InlineHistory.push_back({&Callee, InlineHistoryID}); |
| |
| for (CallBase *ICB : reverse(IFI.InlinedCallSites)) { |
| Function *NewCallee = ICB->getCalledFunction(); |
| assert(!(NewCallee && NewCallee->isIntrinsic()) && |
| "Intrinsic calls should not be tracked."); |
| if (!NewCallee) { |
| // Try to promote an indirect (virtual) call without waiting for |
| // the post-inline cleanup and the next DevirtSCCRepeatedPass |
| // iteration because the next iteration may not happen and we may |
| // miss inlining it. |
| if (tryPromoteCall(*ICB)) |
| NewCallee = ICB->getCalledFunction(); |
| } |
| if (NewCallee) { |
| if (!NewCallee->isDeclaration()) { |
| Calls.push_back({ICB, NewHistoryID}); |
| // Continually inlining through an SCC can result in huge compile |
| // times and bloated code since we arbitrarily stop at some point |
| // when the inliner decides it's not profitable to inline anymore. |
| // We attempt to mitigate this by making these calls exponentially |
| // more expensive. |
| // This doesn't apply to calls in the same SCC since if we do |
| // inline through the SCC the function will end up being |
| // self-recursive which the inliner bails out on, and inlining |
| // within an SCC is necessary for performance. |
| if (CalleeSCC != C && |
| CalleeSCC == CG.lookupSCC(CG.get(*NewCallee))) { |
| Attribute NewCBCostMult = Attribute::get( |
| M.getContext(), |
| InlineConstants::FunctionInlineCostMultiplierAttributeName, |
| itostr(CBCostMult * IntraSCCCostMultiplier)); |
| ICB->addFnAttr(NewCBCostMult); |
| } |
| } |
| } |
| } |
| } |
| |
| // For local functions or discardable functions without comdats, check |
| // whether this makes the callee trivially dead. In that case, we can drop |
| // the body of the function eagerly which may reduce the number of callers |
| // of other functions to one, changing inline cost thresholds. Non-local |
| // discardable functions with comdats are checked later on. |
| bool CalleeWasDeleted = false; |
| if (Callee.isDiscardableIfUnused() && Callee.hasZeroLiveUses() && |
| !CG.isLibFunction(Callee)) { |
| if (Callee.hasLocalLinkage() || !Callee.hasComdat()) { |
| Calls.erase( |
| std::remove_if(Calls.begin() + I + 1, Calls.end(), |
| [&](const std::pair<CallBase *, int> &Call) { |
| return Call.first->getCaller() == &Callee; |
| }), |
| Calls.end()); |
| |
| // Clear the body and queue the function itself for call graph |
| // updating when we finish inlining. |
| makeFunctionBodyUnreachable(Callee); |
| assert(!is_contained(DeadFunctions, &Callee) && |
| "Cannot put cause a function to become dead twice!"); |
| DeadFunctions.push_back(&Callee); |
| CalleeWasDeleted = true; |
| } else { |
| DeadFunctionsInComdats.push_back(&Callee); |
| } |
| } |
| if (CalleeWasDeleted) |
| Advice->recordInliningWithCalleeDeleted(); |
| else |
| Advice->recordInlining(); |
| } |
| |
| // Back the call index up by one to put us in a good position to go around |
| // the outer loop. |
| --I; |
| |
| if (!DidInline) |
| continue; |
| Changed = true; |
| |
| // At this point, since we have made changes we have at least removed |
| // a call instruction. However, in the process we do some incremental |
| // simplification of the surrounding code. This simplification can |
| // essentially do all of the same things as a function pass and we can |
| // re-use the exact same logic for updating the call graph to reflect the |
| // change. |
| |
| // Inside the update, we also update the FunctionAnalysisManager in the |
| // proxy for this particular SCC. We do this as the SCC may have changed and |
| // as we're going to mutate this particular function we want to make sure |
| // the proxy is in place to forward any invalidation events. |
| LazyCallGraph::SCC *OldC = C; |
| C = &updateCGAndAnalysisManagerForCGSCCPass(CG, *C, N, AM, UR, FAM); |
| LLVM_DEBUG(dbgs() << "Updated inlining SCC: " << *C << "\n"); |
| |
| // If this causes an SCC to split apart into multiple smaller SCCs, there |
| // is a subtle risk we need to prepare for. Other transformations may |
| // expose an "infinite inlining" opportunity later, and because of the SCC |
| // mutation, we will revisit this function and potentially re-inline. If we |
| // do, and that re-inlining also has the potentially to mutate the SCC |
| // structure, the infinite inlining problem can manifest through infinite |
| // SCC splits and merges. To avoid this, we capture the originating caller |
| // node and the SCC containing the call edge. This is a slight over |
| // approximation of the possible inlining decisions that must be avoided, |
| // but is relatively efficient to store. We use C != OldC to know when |
| // a new SCC is generated and the original SCC may be generated via merge |
| // in later iterations. |
| // |
| // It is also possible that even if no new SCC is generated |
| // (i.e., C == OldC), the original SCC could be split and then merged |
| // into the same one as itself. and the original SCC will be added into |
| // UR.CWorklist again, we want to catch such cases too. |
| // |
| // FIXME: This seems like a very heavyweight way of retaining the inline |
| // history, we should look for a more efficient way of tracking it. |
| if ((C != OldC || UR.CWorklist.count(OldC)) && |
| llvm::any_of(InlinedCallees, [&](Function *Callee) { |
| return CG.lookupSCC(*CG.lookup(*Callee)) == OldC; |
| })) { |
| LLVM_DEBUG(dbgs() << "Inlined an internal call edge and split an SCC, " |
| "retaining this to avoid infinite inlining.\n"); |
| UR.InlinedInternalEdges.insert({&N, OldC}); |
| } |
| InlinedCallees.clear(); |
| |
| // Invalidate analyses for this function now so that we don't have to |
| // invalidate analyses for all functions in this SCC later. |
| FAM.invalidate(F, PreservedAnalyses::none()); |
| } |
| |
| // We must ensure that we only delete functions with comdats if every function |
| // in the comdat is going to be deleted. |
| if (!DeadFunctionsInComdats.empty()) { |
| filterDeadComdatFunctions(DeadFunctionsInComdats); |
| for (auto *Callee : DeadFunctionsInComdats) |
| makeFunctionBodyUnreachable(*Callee); |
| DeadFunctions.append(DeadFunctionsInComdats); |
| } |
| |
| // Now that we've finished inlining all of the calls across this SCC, delete |
| // all of the trivially dead functions, updating the call graph and the CGSCC |
| // pass manager in the process. |
| // |
| // Note that this walks a pointer set which has non-deterministic order but |
| // that is OK as all we do is delete things and add pointers to unordered |
| // sets. |
| for (Function *DeadF : DeadFunctions) { |
| CG.markDeadFunction(*DeadF); |
| // Get the necessary information out of the call graph and nuke the |
| // function there. Also, clear out any cached analyses. |
| auto &DeadC = *CG.lookupSCC(*CG.lookup(*DeadF)); |
| FAM.clear(*DeadF, DeadF->getName()); |
| AM.clear(DeadC, DeadC.getName()); |
| |
| // Mark the relevant parts of the call graph as invalid so we don't visit |
| // them. |
| UR.InvalidatedSCCs.insert(&DeadC); |
| |
| UR.DeadFunctions.push_back(DeadF); |
| |
| ++NumDeleted; |
| } |
| |
| if (!Changed) |
| return PreservedAnalyses::all(); |
| |
| PreservedAnalyses PA; |
| // Even if we change the IR, we update the core CGSCC data structures and so |
| // can preserve the proxy to the function analysis manager. |
| PA.preserve<FunctionAnalysisManagerCGSCCProxy>(); |
| // We have already invalidated all analyses on modified functions. |
| PA.preserveSet<AllAnalysesOn<Function>>(); |
| return PA; |
| } |
| |
| ModuleInlinerWrapperPass::ModuleInlinerWrapperPass(InlineParams Params, |
| bool MandatoryFirst, |
| InlineContext IC, |
| InliningAdvisorMode Mode, |
| unsigned MaxDevirtIterations) |
| : Params(Params), IC(IC), Mode(Mode), |
| MaxDevirtIterations(MaxDevirtIterations) { |
| // Run the inliner first. The theory is that we are walking bottom-up and so |
| // the callees have already been fully optimized, and we want to inline them |
| // into the callers so that our optimizations can reflect that. |
| // For PreLinkThinLTO pass, we disable hot-caller heuristic for sample PGO |
| // because it makes profile annotation in the backend inaccurate. |
| if (MandatoryFirst) { |
| PM.addPass(InlinerPass(/*OnlyMandatory*/ true)); |
| if (EnablePostSCCAdvisorPrinting) |
| PM.addPass(InlineAdvisorAnalysisPrinterPass(dbgs())); |
| } |
| PM.addPass(InlinerPass()); |
| if (EnablePostSCCAdvisorPrinting) |
| PM.addPass(InlineAdvisorAnalysisPrinterPass(dbgs())); |
| } |
| |
| PreservedAnalyses ModuleInlinerWrapperPass::run(Module &M, |
| ModuleAnalysisManager &MAM) { |
| auto &IAA = MAM.getResult<InlineAdvisorAnalysis>(M); |
| if (!IAA.tryCreate(Params, Mode, |
| {CGSCCInlineReplayFile, |
| CGSCCInlineReplayScope, |
| CGSCCInlineReplayFallback, |
| {CGSCCInlineReplayFormat}}, |
| IC)) { |
| M.getContext().emitError( |
| "Could not setup Inlining Advisor for the requested " |
| "mode and/or options"); |
| return PreservedAnalyses::all(); |
| } |
| |
| // We wrap the CGSCC pipeline in a devirtualization repeater. This will try |
| // to detect when we devirtualize indirect calls and iterate the SCC passes |
| // in that case to try and catch knock-on inlining or function attrs |
| // opportunities. Then we add it to the module pipeline by walking the SCCs |
| // in postorder (or bottom-up). |
| // If MaxDevirtIterations is 0, we just don't use the devirtualization |
| // wrapper. |
| if (MaxDevirtIterations == 0) |
| MPM.addPass(createModuleToPostOrderCGSCCPassAdaptor(std::move(PM))); |
| else |
| MPM.addPass(createModuleToPostOrderCGSCCPassAdaptor( |
| createDevirtSCCRepeatedPass(std::move(PM), MaxDevirtIterations))); |
| |
| MPM.addPass(std::move(AfterCGMPM)); |
| MPM.run(M, MAM); |
| |
| // Discard the InlineAdvisor, a subsequent inlining session should construct |
| // its own. |
| auto PA = PreservedAnalyses::all(); |
| if (!KeepAdvisorForPrinting) |
| PA.abandon<InlineAdvisorAnalysis>(); |
| return PA; |
| } |
| |
| void InlinerPass::printPipeline( |
| raw_ostream &OS, function_ref<StringRef(StringRef)> MapClassName2PassName) { |
| static_cast<PassInfoMixin<InlinerPass> *>(this)->printPipeline( |
| OS, MapClassName2PassName); |
| if (OnlyMandatory) |
| OS << "<only-mandatory>"; |
| } |
| |
| void ModuleInlinerWrapperPass::printPipeline( |
| raw_ostream &OS, function_ref<StringRef(StringRef)> MapClassName2PassName) { |
| // Print some info about passes added to the wrapper. This is however |
| // incomplete as InlineAdvisorAnalysis part isn't included (which also depends |
| // on Params and Mode). |
| if (!MPM.isEmpty()) { |
| MPM.printPipeline(OS, MapClassName2PassName); |
| OS << ','; |
| } |
| OS << "cgscc("; |
| if (MaxDevirtIterations != 0) |
| OS << "devirt<" << MaxDevirtIterations << ">("; |
| PM.printPipeline(OS, MapClassName2PassName); |
| if (MaxDevirtIterations != 0) |
| OS << ')'; |
| OS << ')'; |
| } |
