689 lines
28 KiB
C++
689 lines
28 KiB
C++
//===- CGSCCPassManager.cpp - Managing & running CGSCC passes -------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Analysis/CGSCCPassManager.h"
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#include "llvm/ADT/ArrayRef.h"
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#include "llvm/ADT/Optional.h"
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#include "llvm/ADT/STLExtras.h"
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#include "llvm/ADT/SetVector.h"
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#include "llvm/ADT/SmallPtrSet.h"
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#include "llvm/ADT/SmallVector.h"
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#include "llvm/ADT/iterator_range.h"
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#include "llvm/Analysis/LazyCallGraph.h"
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#include "llvm/IR/CallSite.h"
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#include "llvm/IR/Constant.h"
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#include "llvm/IR/InstIterator.h"
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#include "llvm/IR/Instruction.h"
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#include "llvm/IR/PassManager.h"
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#include "llvm/Support/Casting.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Support/raw_ostream.h"
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#include <algorithm>
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#include <cassert>
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#include <iterator>
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#define DEBUG_TYPE "cgscc"
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using namespace llvm;
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// Explicit template instantiations and specialization defininitions for core
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// template typedefs.
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namespace llvm {
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// Explicit instantiations for the core proxy templates.
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template class AllAnalysesOn<LazyCallGraph::SCC>;
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template class AnalysisManager<LazyCallGraph::SCC, LazyCallGraph &>;
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template class PassManager<LazyCallGraph::SCC, CGSCCAnalysisManager,
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LazyCallGraph &, CGSCCUpdateResult &>;
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template class InnerAnalysisManagerProxy<CGSCCAnalysisManager, Module>;
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template class OuterAnalysisManagerProxy<ModuleAnalysisManager,
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LazyCallGraph::SCC, LazyCallGraph &>;
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template class OuterAnalysisManagerProxy<CGSCCAnalysisManager, Function>;
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/// Explicitly specialize the pass manager run method to handle call graph
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/// updates.
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template <>
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PreservedAnalyses
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PassManager<LazyCallGraph::SCC, CGSCCAnalysisManager, LazyCallGraph &,
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CGSCCUpdateResult &>::run(LazyCallGraph::SCC &InitialC,
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CGSCCAnalysisManager &AM,
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LazyCallGraph &G, CGSCCUpdateResult &UR) {
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PreservedAnalyses PA = PreservedAnalyses::all();
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if (DebugLogging)
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dbgs() << "Starting CGSCC pass manager run.\n";
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// The SCC may be refined while we are running passes over it, so set up
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// a pointer that we can update.
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LazyCallGraph::SCC *C = &InitialC;
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for (auto &Pass : Passes) {
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if (DebugLogging)
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dbgs() << "Running pass: " << Pass->name() << " on " << *C << "\n";
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PreservedAnalyses PassPA = Pass->run(*C, AM, G, UR);
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// Update the SCC if necessary.
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C = UR.UpdatedC ? UR.UpdatedC : C;
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// If the CGSCC pass wasn't able to provide a valid updated SCC, the
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// current SCC may simply need to be skipped if invalid.
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if (UR.InvalidatedSCCs.count(C)) {
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DEBUG(dbgs() << "Skipping invalidated root or island SCC!\n");
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break;
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}
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// Check that we didn't miss any update scenario.
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assert(C->begin() != C->end() && "Cannot have an empty SCC!");
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// Update the analysis manager as each pass runs and potentially
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// invalidates analyses.
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AM.invalidate(*C, PassPA);
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// Finally, we intersect the final preserved analyses to compute the
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// aggregate preserved set for this pass manager.
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PA.intersect(std::move(PassPA));
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// FIXME: Historically, the pass managers all called the LLVM context's
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// yield function here. We don't have a generic way to acquire the
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// context and it isn't yet clear what the right pattern is for yielding
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// in the new pass manager so it is currently omitted.
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// ...getContext().yield();
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}
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// Invaliadtion was handled after each pass in the above loop for the current
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// SCC. Therefore, the remaining analysis results in the AnalysisManager are
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// preserved. We mark this with a set so that we don't need to inspect each
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// one individually.
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PA.preserveSet<AllAnalysesOn<LazyCallGraph::SCC>>();
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if (DebugLogging)
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dbgs() << "Finished CGSCC pass manager run.\n";
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return PA;
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}
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bool CGSCCAnalysisManagerModuleProxy::Result::invalidate(
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Module &M, const PreservedAnalyses &PA,
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ModuleAnalysisManager::Invalidator &Inv) {
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// If literally everything is preserved, we're done.
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if (PA.areAllPreserved())
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return false; // This is still a valid proxy.
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// If this proxy or the call graph is going to be invalidated, we also need
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// to clear all the keys coming from that analysis.
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//
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// We also directly invalidate the FAM's module proxy if necessary, and if
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// that proxy isn't preserved we can't preserve this proxy either. We rely on
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// it to handle module -> function analysis invalidation in the face of
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// structural changes and so if it's unavailable we conservatively clear the
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// entire SCC layer as well rather than trying to do invalidation ourselves.
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auto PAC = PA.getChecker<CGSCCAnalysisManagerModuleProxy>();
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if (!(PAC.preserved() || PAC.preservedSet<AllAnalysesOn<Module>>()) ||
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Inv.invalidate<LazyCallGraphAnalysis>(M, PA) ||
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Inv.invalidate<FunctionAnalysisManagerModuleProxy>(M, PA)) {
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InnerAM->clear();
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// And the proxy itself should be marked as invalid so that we can observe
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// the new call graph. This isn't strictly necessary because we cheat
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// above, but is still useful.
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return true;
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}
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// Directly check if the relevant set is preserved so we can short circuit
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// invalidating SCCs below.
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bool AreSCCAnalysesPreserved =
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PA.allAnalysesInSetPreserved<AllAnalysesOn<LazyCallGraph::SCC>>();
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// Ok, we have a graph, so we can propagate the invalidation down into it.
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G->buildRefSCCs();
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for (auto &RC : G->postorder_ref_sccs())
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for (auto &C : RC) {
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Optional<PreservedAnalyses> InnerPA;
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// Check to see whether the preserved set needs to be adjusted based on
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// module-level analysis invalidation triggering deferred invalidation
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// for this SCC.
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if (auto *OuterProxy =
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InnerAM->getCachedResult<ModuleAnalysisManagerCGSCCProxy>(C))
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for (const auto &OuterInvalidationPair :
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OuterProxy->getOuterInvalidations()) {
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AnalysisKey *OuterAnalysisID = OuterInvalidationPair.first;
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const auto &InnerAnalysisIDs = OuterInvalidationPair.second;
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if (Inv.invalidate(OuterAnalysisID, M, PA)) {
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if (!InnerPA)
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InnerPA = PA;
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for (AnalysisKey *InnerAnalysisID : InnerAnalysisIDs)
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InnerPA->abandon(InnerAnalysisID);
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}
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}
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// Check if we needed a custom PA set. If so we'll need to run the inner
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// invalidation.
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if (InnerPA) {
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InnerAM->invalidate(C, *InnerPA);
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continue;
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}
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// Otherwise we only need to do invalidation if the original PA set didn't
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// preserve all SCC analyses.
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if (!AreSCCAnalysesPreserved)
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InnerAM->invalidate(C, PA);
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}
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// Return false to indicate that this result is still a valid proxy.
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return false;
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}
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template <>
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CGSCCAnalysisManagerModuleProxy::Result
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CGSCCAnalysisManagerModuleProxy::run(Module &M, ModuleAnalysisManager &AM) {
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// Force the Function analysis manager to also be available so that it can
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// be accessed in an SCC analysis and proxied onward to function passes.
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// FIXME: It is pretty awkward to just drop the result here and assert that
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// we can find it again later.
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(void)AM.getResult<FunctionAnalysisManagerModuleProxy>(M);
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return Result(*InnerAM, AM.getResult<LazyCallGraphAnalysis>(M));
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}
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AnalysisKey FunctionAnalysisManagerCGSCCProxy::Key;
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FunctionAnalysisManagerCGSCCProxy::Result
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FunctionAnalysisManagerCGSCCProxy::run(LazyCallGraph::SCC &C,
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CGSCCAnalysisManager &AM,
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LazyCallGraph &CG) {
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// Collect the FunctionAnalysisManager from the Module layer and use that to
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// build the proxy result.
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//
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// This allows us to rely on the FunctionAnalysisMangaerModuleProxy to
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// invalidate the function analyses.
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auto &MAM = AM.getResult<ModuleAnalysisManagerCGSCCProxy>(C, CG).getManager();
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Module &M = *C.begin()->getFunction().getParent();
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auto *FAMProxy = MAM.getCachedResult<FunctionAnalysisManagerModuleProxy>(M);
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assert(FAMProxy && "The CGSCC pass manager requires that the FAM module "
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"proxy is run on the module prior to entering the CGSCC "
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"walk.");
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// Note that we special-case invalidation handling of this proxy in the CGSCC
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// analysis manager's Module proxy. This avoids the need to do anything
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// special here to recompute all of this if ever the FAM's module proxy goes
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// away.
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return Result(FAMProxy->getManager());
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}
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bool FunctionAnalysisManagerCGSCCProxy::Result::invalidate(
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LazyCallGraph::SCC &C, const PreservedAnalyses &PA,
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CGSCCAnalysisManager::Invalidator &Inv) {
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// If literally everything is preserved, we're done.
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if (PA.areAllPreserved())
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return false; // This is still a valid proxy.
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// If this proxy isn't marked as preserved, then even if the result remains
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// valid, the key itself may no longer be valid, so we clear everything.
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//
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// Note that in order to preserve this proxy, a module pass must ensure that
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// the FAM has been completely updated to handle the deletion of functions.
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// Specifically, any FAM-cached results for those functions need to have been
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// forcibly cleared. When preserved, this proxy will only invalidate results
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// cached on functions *still in the module* at the end of the module pass.
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auto PAC = PA.getChecker<FunctionAnalysisManagerCGSCCProxy>();
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if (!PAC.preserved() && !PAC.preservedSet<AllAnalysesOn<LazyCallGraph::SCC>>()) {
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for (LazyCallGraph::Node &N : C)
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FAM->clear(N.getFunction(), N.getFunction().getName());
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return true;
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}
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// Directly check if the relevant set is preserved.
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bool AreFunctionAnalysesPreserved =
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PA.allAnalysesInSetPreserved<AllAnalysesOn<Function>>();
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// Now walk all the functions to see if any inner analysis invalidation is
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// necessary.
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for (LazyCallGraph::Node &N : C) {
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Function &F = N.getFunction();
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Optional<PreservedAnalyses> FunctionPA;
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// Check to see whether the preserved set needs to be pruned based on
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// SCC-level analysis invalidation that triggers deferred invalidation
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// registered with the outer analysis manager proxy for this function.
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if (auto *OuterProxy =
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FAM->getCachedResult<CGSCCAnalysisManagerFunctionProxy>(F))
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for (const auto &OuterInvalidationPair :
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OuterProxy->getOuterInvalidations()) {
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AnalysisKey *OuterAnalysisID = OuterInvalidationPair.first;
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const auto &InnerAnalysisIDs = OuterInvalidationPair.second;
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if (Inv.invalidate(OuterAnalysisID, C, PA)) {
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if (!FunctionPA)
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FunctionPA = PA;
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for (AnalysisKey *InnerAnalysisID : InnerAnalysisIDs)
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FunctionPA->abandon(InnerAnalysisID);
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}
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}
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// Check if we needed a custom PA set, and if so we'll need to run the
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// inner invalidation.
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if (FunctionPA) {
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FAM->invalidate(F, *FunctionPA);
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continue;
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}
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// Otherwise we only need to do invalidation if the original PA set didn't
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// preserve all function analyses.
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if (!AreFunctionAnalysesPreserved)
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FAM->invalidate(F, PA);
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}
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// Return false to indicate that this result is still a valid proxy.
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return false;
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}
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} // end namespace llvm
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/// When a new SCC is created for the graph and there might be function
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/// analysis results cached for the functions now in that SCC two forms of
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/// updates are required.
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///
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/// First, a proxy from the SCC to the FunctionAnalysisManager needs to be
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/// created so that any subsequent invalidation events to the SCC are
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/// propagated to the function analysis results cached for functions within it.
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///
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/// Second, if any of the functions within the SCC have analysis results with
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/// outer analysis dependencies, then those dependencies would point to the
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/// *wrong* SCC's analysis result. We forcibly invalidate the necessary
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/// function analyses so that they don't retain stale handles.
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static void updateNewSCCFunctionAnalyses(LazyCallGraph::SCC &C,
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LazyCallGraph &G,
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CGSCCAnalysisManager &AM) {
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// Get the relevant function analysis manager.
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auto &FAM =
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AM.getResult<FunctionAnalysisManagerCGSCCProxy>(C, G).getManager();
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// Now walk the functions in this SCC and invalidate any function analysis
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// results that might have outer dependencies on an SCC analysis.
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for (LazyCallGraph::Node &N : C) {
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Function &F = N.getFunction();
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auto *OuterProxy =
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FAM.getCachedResult<CGSCCAnalysisManagerFunctionProxy>(F);
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if (!OuterProxy)
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// No outer analyses were queried, nothing to do.
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continue;
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// Forcibly abandon all the inner analyses with dependencies, but
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// invalidate nothing else.
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auto PA = PreservedAnalyses::all();
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for (const auto &OuterInvalidationPair :
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OuterProxy->getOuterInvalidations()) {
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const auto &InnerAnalysisIDs = OuterInvalidationPair.second;
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for (AnalysisKey *InnerAnalysisID : InnerAnalysisIDs)
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PA.abandon(InnerAnalysisID);
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}
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// Now invalidate anything we found.
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FAM.invalidate(F, PA);
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}
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}
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/// Helper function to update both the \c CGSCCAnalysisManager \p AM and the \c
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/// CGSCCPassManager's \c CGSCCUpdateResult \p UR based on a range of newly
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/// added SCCs.
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///
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/// The range of new SCCs must be in postorder already. The SCC they were split
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/// out of must be provided as \p C. The current node being mutated and
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/// triggering updates must be passed as \p N.
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///
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/// This function returns the SCC containing \p N. This will be either \p C if
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/// no new SCCs have been split out, or it will be the new SCC containing \p N.
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template <typename SCCRangeT>
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static LazyCallGraph::SCC *
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incorporateNewSCCRange(const SCCRangeT &NewSCCRange, LazyCallGraph &G,
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LazyCallGraph::Node &N, LazyCallGraph::SCC *C,
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CGSCCAnalysisManager &AM, CGSCCUpdateResult &UR) {
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using SCC = LazyCallGraph::SCC;
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if (NewSCCRange.begin() == NewSCCRange.end())
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return C;
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// Add the current SCC to the worklist as its shape has changed.
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UR.CWorklist.insert(C);
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DEBUG(dbgs() << "Enqueuing the existing SCC in the worklist:" << *C << "\n");
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SCC *OldC = C;
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// Update the current SCC. Note that if we have new SCCs, this must actually
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// change the SCC.
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assert(C != &*NewSCCRange.begin() &&
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"Cannot insert new SCCs without changing current SCC!");
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C = &*NewSCCRange.begin();
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assert(G.lookupSCC(N) == C && "Failed to update current SCC!");
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// If we had a cached FAM proxy originally, we will want to create more of
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// them for each SCC that was split off.
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bool NeedFAMProxy =
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AM.getCachedResult<FunctionAnalysisManagerCGSCCProxy>(*OldC) != nullptr;
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// We need to propagate an invalidation call to all but the newly current SCC
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// because the outer pass manager won't do that for us after splitting them.
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// FIXME: We should accept a PreservedAnalysis from the CG updater so that if
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// there are preserved ananalyses we can avoid invalidating them here for
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// split-off SCCs.
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// We know however that this will preserve any FAM proxy so go ahead and mark
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// that.
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PreservedAnalyses PA;
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PA.preserve<FunctionAnalysisManagerCGSCCProxy>();
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AM.invalidate(*OldC, PA);
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// Ensure the now-current SCC's function analyses are updated.
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if (NeedFAMProxy)
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updateNewSCCFunctionAnalyses(*C, G, AM);
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for (SCC &NewC : llvm::reverse(make_range(std::next(NewSCCRange.begin()),
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NewSCCRange.end()))) {
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assert(C != &NewC && "No need to re-visit the current SCC!");
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assert(OldC != &NewC && "Already handled the original SCC!");
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UR.CWorklist.insert(&NewC);
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DEBUG(dbgs() << "Enqueuing a newly formed SCC:" << NewC << "\n");
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// Ensure new SCCs' function analyses are updated.
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if (NeedFAMProxy)
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updateNewSCCFunctionAnalyses(NewC, G, AM);
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// Also propagate a normal invalidation to the new SCC as only the current
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// will get one from the pass manager infrastructure.
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AM.invalidate(NewC, PA);
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}
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return C;
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}
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LazyCallGraph::SCC &llvm::updateCGAndAnalysisManagerForFunctionPass(
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LazyCallGraph &G, LazyCallGraph::SCC &InitialC, LazyCallGraph::Node &N,
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CGSCCAnalysisManager &AM, CGSCCUpdateResult &UR) {
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using Node = LazyCallGraph::Node;
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using Edge = LazyCallGraph::Edge;
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using SCC = LazyCallGraph::SCC;
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using RefSCC = LazyCallGraph::RefSCC;
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RefSCC &InitialRC = InitialC.getOuterRefSCC();
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SCC *C = &InitialC;
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RefSCC *RC = &InitialRC;
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Function &F = N.getFunction();
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// Walk the function body and build up the set of retained, promoted, and
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// demoted edges.
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SmallVector<Constant *, 16> Worklist;
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SmallPtrSet<Constant *, 16> Visited;
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SmallPtrSet<Node *, 16> RetainedEdges;
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SmallSetVector<Node *, 4> PromotedRefTargets;
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SmallSetVector<Node *, 4> DemotedCallTargets;
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// First walk the function and handle all called functions. We do this first
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// because if there is a single call edge, whether there are ref edges is
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// irrelevant.
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for (Instruction &I : instructions(F))
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if (auto CS = CallSite(&I))
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if (Function *Callee = CS.getCalledFunction())
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if (Visited.insert(Callee).second && !Callee->isDeclaration()) {
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Node &CalleeN = *G.lookup(*Callee);
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Edge *E = N->lookup(CalleeN);
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// FIXME: We should really handle adding new calls. While it will
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// make downstream usage more complex, there is no fundamental
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// limitation and it will allow passes within the CGSCC to be a bit
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// more flexible in what transforms they can do. Until then, we
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// verify that new calls haven't been introduced.
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assert(E && "No function transformations should introduce *new* "
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"call edges! Any new calls should be modeled as "
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"promoted existing ref edges!");
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bool Inserted = RetainedEdges.insert(&CalleeN).second;
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(void)Inserted;
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assert(Inserted && "We should never visit a function twice.");
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if (!E->isCall())
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PromotedRefTargets.insert(&CalleeN);
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}
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// Now walk all references.
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for (Instruction &I : instructions(F))
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for (Value *Op : I.operand_values())
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if (auto *C = dyn_cast<Constant>(Op))
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if (Visited.insert(C).second)
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Worklist.push_back(C);
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auto VisitRef = [&](Function &Referee) {
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Node &RefereeN = *G.lookup(Referee);
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Edge *E = N->lookup(RefereeN);
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// FIXME: Similarly to new calls, we also currently preclude
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// introducing new references. See above for details.
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assert(E && "No function transformations should introduce *new* ref "
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"edges! Any new ref edges would require IPO which "
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"function passes aren't allowed to do!");
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bool Inserted = RetainedEdges.insert(&RefereeN).second;
|
|
(void)Inserted;
|
|
assert(Inserted && "We should never visit a function twice.");
|
|
if (E->isCall())
|
|
DemotedCallTargets.insert(&RefereeN);
|
|
};
|
|
LazyCallGraph::visitReferences(Worklist, Visited, VisitRef);
|
|
|
|
// Include synthetic reference edges to known, defined lib functions.
|
|
for (auto *F : G.getLibFunctions())
|
|
// While the list of lib functions doesn't have repeats, don't re-visit
|
|
// anything handled above.
|
|
if (!Visited.count(F))
|
|
VisitRef(*F);
|
|
|
|
// First remove all of the edges that are no longer present in this function.
|
|
// The first step makes these edges uniformly ref edges and accumulates them
|
|
// into a separate data structure so removal doesn't invalidate anything.
|
|
SmallVector<Node *, 4> DeadTargets;
|
|
for (Edge &E : *N) {
|
|
if (RetainedEdges.count(&E.getNode()))
|
|
continue;
|
|
|
|
SCC &TargetC = *G.lookupSCC(E.getNode());
|
|
RefSCC &TargetRC = TargetC.getOuterRefSCC();
|
|
if (&TargetRC == RC && E.isCall()) {
|
|
if (C != &TargetC) {
|
|
// For separate SCCs this is trivial.
|
|
RC->switchTrivialInternalEdgeToRef(N, E.getNode());
|
|
} else {
|
|
// Now update the call graph.
|
|
C = incorporateNewSCCRange(RC->switchInternalEdgeToRef(N, E.getNode()),
|
|
G, N, C, AM, UR);
|
|
}
|
|
}
|
|
|
|
// Now that this is ready for actual removal, put it into our list.
|
|
DeadTargets.push_back(&E.getNode());
|
|
}
|
|
// Remove the easy cases quickly and actually pull them out of our list.
|
|
DeadTargets.erase(
|
|
llvm::remove_if(DeadTargets,
|
|
[&](Node *TargetN) {
|
|
SCC &TargetC = *G.lookupSCC(*TargetN);
|
|
RefSCC &TargetRC = TargetC.getOuterRefSCC();
|
|
|
|
// We can't trivially remove internal targets, so skip
|
|
// those.
|
|
if (&TargetRC == RC)
|
|
return false;
|
|
|
|
RC->removeOutgoingEdge(N, *TargetN);
|
|
DEBUG(dbgs() << "Deleting outgoing edge from '" << N
|
|
<< "' to '" << TargetN << "'\n");
|
|
return true;
|
|
}),
|
|
DeadTargets.end());
|
|
|
|
// Now do a batch removal of the internal ref edges left.
|
|
auto NewRefSCCs = RC->removeInternalRefEdge(N, DeadTargets);
|
|
if (!NewRefSCCs.empty()) {
|
|
// The old RefSCC is dead, mark it as such.
|
|
UR.InvalidatedRefSCCs.insert(RC);
|
|
|
|
// Note that we don't bother to invalidate analyses as ref-edge
|
|
// connectivity is not really observable in any way and is intended
|
|
// exclusively to be used for ordering of transforms rather than for
|
|
// analysis conclusions.
|
|
|
|
// Update RC to the "bottom".
|
|
assert(G.lookupSCC(N) == C && "Changed the SCC when splitting RefSCCs!");
|
|
RC = &C->getOuterRefSCC();
|
|
assert(G.lookupRefSCC(N) == RC && "Failed to update current RefSCC!");
|
|
|
|
// The RC worklist is in reverse postorder, so we enqueue the new ones in
|
|
// RPO except for the one which contains the source node as that is the
|
|
// "bottom" we will continue processing in the bottom-up walk.
|
|
assert(NewRefSCCs.front() == RC &&
|
|
"New current RefSCC not first in the returned list!");
|
|
for (RefSCC *NewRC : llvm::reverse(make_range(std::next(NewRefSCCs.begin()),
|
|
NewRefSCCs.end()))) {
|
|
assert(NewRC != RC && "Should not encounter the current RefSCC further "
|
|
"in the postorder list of new RefSCCs.");
|
|
UR.RCWorklist.insert(NewRC);
|
|
DEBUG(dbgs() << "Enqueuing a new RefSCC in the update worklist: "
|
|
<< *NewRC << "\n");
|
|
}
|
|
}
|
|
|
|
// Next demote all the call edges that are now ref edges. This helps make
|
|
// the SCCs small which should minimize the work below as we don't want to
|
|
// form cycles that this would break.
|
|
for (Node *RefTarget : DemotedCallTargets) {
|
|
SCC &TargetC = *G.lookupSCC(*RefTarget);
|
|
RefSCC &TargetRC = TargetC.getOuterRefSCC();
|
|
|
|
// The easy case is when the target RefSCC is not this RefSCC. This is
|
|
// only supported when the target RefSCC is a child of this RefSCC.
|
|
if (&TargetRC != RC) {
|
|
assert(RC->isAncestorOf(TargetRC) &&
|
|
"Cannot potentially form RefSCC cycles here!");
|
|
RC->switchOutgoingEdgeToRef(N, *RefTarget);
|
|
DEBUG(dbgs() << "Switch outgoing call edge to a ref edge from '" << N
|
|
<< "' to '" << *RefTarget << "'\n");
|
|
continue;
|
|
}
|
|
|
|
// We are switching an internal call edge to a ref edge. This may split up
|
|
// some SCCs.
|
|
if (C != &TargetC) {
|
|
// For separate SCCs this is trivial.
|
|
RC->switchTrivialInternalEdgeToRef(N, *RefTarget);
|
|
continue;
|
|
}
|
|
|
|
// Now update the call graph.
|
|
C = incorporateNewSCCRange(RC->switchInternalEdgeToRef(N, *RefTarget), G, N,
|
|
C, AM, UR);
|
|
}
|
|
|
|
// Now promote ref edges into call edges.
|
|
for (Node *CallTarget : PromotedRefTargets) {
|
|
SCC &TargetC = *G.lookupSCC(*CallTarget);
|
|
RefSCC &TargetRC = TargetC.getOuterRefSCC();
|
|
|
|
// The easy case is when the target RefSCC is not this RefSCC. This is
|
|
// only supported when the target RefSCC is a child of this RefSCC.
|
|
if (&TargetRC != RC) {
|
|
assert(RC->isAncestorOf(TargetRC) &&
|
|
"Cannot potentially form RefSCC cycles here!");
|
|
RC->switchOutgoingEdgeToCall(N, *CallTarget);
|
|
DEBUG(dbgs() << "Switch outgoing ref edge to a call edge from '" << N
|
|
<< "' to '" << *CallTarget << "'\n");
|
|
continue;
|
|
}
|
|
DEBUG(dbgs() << "Switch an internal ref edge to a call edge from '" << N
|
|
<< "' to '" << *CallTarget << "'\n");
|
|
|
|
// Otherwise we are switching an internal ref edge to a call edge. This
|
|
// may merge away some SCCs, and we add those to the UpdateResult. We also
|
|
// need to make sure to update the worklist in the event SCCs have moved
|
|
// before the current one in the post-order sequence
|
|
bool HasFunctionAnalysisProxy = false;
|
|
auto InitialSCCIndex = RC->find(*C) - RC->begin();
|
|
bool FormedCycle = RC->switchInternalEdgeToCall(
|
|
N, *CallTarget, [&](ArrayRef<SCC *> MergedSCCs) {
|
|
for (SCC *MergedC : MergedSCCs) {
|
|
assert(MergedC != &TargetC && "Cannot merge away the target SCC!");
|
|
|
|
HasFunctionAnalysisProxy |=
|
|
AM.getCachedResult<FunctionAnalysisManagerCGSCCProxy>(
|
|
*MergedC) != nullptr;
|
|
|
|
// Mark that this SCC will no longer be valid.
|
|
UR.InvalidatedSCCs.insert(MergedC);
|
|
|
|
// FIXME: We should really do a 'clear' here to forcibly release
|
|
// memory, but we don't have a good way of doing that and
|
|
// preserving the function analyses.
|
|
auto PA = PreservedAnalyses::allInSet<AllAnalysesOn<Function>>();
|
|
PA.preserve<FunctionAnalysisManagerCGSCCProxy>();
|
|
AM.invalidate(*MergedC, PA);
|
|
}
|
|
});
|
|
|
|
// If we formed a cycle by creating this call, we need to update more data
|
|
// structures.
|
|
if (FormedCycle) {
|
|
C = &TargetC;
|
|
assert(G.lookupSCC(N) == C && "Failed to update current SCC!");
|
|
|
|
// If one of the invalidated SCCs had a cached proxy to a function
|
|
// analysis manager, we need to create a proxy in the new current SCC as
|
|
// the invaliadted SCCs had their functions moved.
|
|
if (HasFunctionAnalysisProxy)
|
|
AM.getResult<FunctionAnalysisManagerCGSCCProxy>(*C, G);
|
|
|
|
// Any analyses cached for this SCC are no longer precise as the shape
|
|
// has changed by introducing this cycle. However, we have taken care to
|
|
// update the proxies so it remains valide.
|
|
auto PA = PreservedAnalyses::allInSet<AllAnalysesOn<Function>>();
|
|
PA.preserve<FunctionAnalysisManagerCGSCCProxy>();
|
|
AM.invalidate(*C, PA);
|
|
}
|
|
auto NewSCCIndex = RC->find(*C) - RC->begin();
|
|
// If we have actually moved an SCC to be topologically "below" the current
|
|
// one due to merging, we will need to revisit the current SCC after
|
|
// visiting those moved SCCs.
|
|
//
|
|
// It is critical that we *do not* revisit the current SCC unless we
|
|
// actually move SCCs in the process of merging because otherwise we may
|
|
// form a cycle where an SCC is split apart, merged, split, merged and so
|
|
// on infinitely.
|
|
if (InitialSCCIndex < NewSCCIndex) {
|
|
// Put our current SCC back onto the worklist as we'll visit other SCCs
|
|
// that are now definitively ordered prior to the current one in the
|
|
// post-order sequence, and may end up observing more precise context to
|
|
// optimize the current SCC.
|
|
UR.CWorklist.insert(C);
|
|
DEBUG(dbgs() << "Enqueuing the existing SCC in the worklist: " << *C
|
|
<< "\n");
|
|
// Enqueue in reverse order as we pop off the back of the worklist.
|
|
for (SCC &MovedC : llvm::reverse(make_range(RC->begin() + InitialSCCIndex,
|
|
RC->begin() + NewSCCIndex))) {
|
|
UR.CWorklist.insert(&MovedC);
|
|
DEBUG(dbgs() << "Enqueuing a newly earlier in post-order SCC: "
|
|
<< MovedC << "\n");
|
|
}
|
|
}
|
|
}
|
|
|
|
assert(!UR.InvalidatedSCCs.count(C) && "Invalidated the current SCC!");
|
|
assert(!UR.InvalidatedRefSCCs.count(RC) && "Invalidated the current RefSCC!");
|
|
assert(&C->getOuterRefSCC() == RC && "Current SCC not in current RefSCC!");
|
|
|
|
// Record the current RefSCC and SCC for higher layers of the CGSCC pass
|
|
// manager now that all the updates have been applied.
|
|
if (RC != &InitialRC)
|
|
UR.UpdatedRC = RC;
|
|
if (C != &InitialC)
|
|
UR.UpdatedC = C;
|
|
|
|
return *C;
|
|
}
|