Files
swift-mirror/lib/SILOptimizer/ARC/ARCLoopOpts.cpp
Erik Eckstein d2fc6eb3b5 AliasAnalysis: make AliasAnalysis a function analysis and simplify the cache keys
Instead of caching alias results globally for the module, make AliasAnalysis a FunctionAnalysisBase which caches the alias results per function.
Why?
* So far the result caches could only grow. They were reset when they reached a certain size. This was not ideal. Now, they are invalidated whenever the function changes.
* It was not possible to actually invalidate an alias analysis result. This is required, for example in TempRValueOpt and TempLValueOpt (so far it was done manually with invalidateInstruction).
* Type based alias analysis results were also cached for the whole module, while it is actually dependent on the function, because it depends on the function's resilience expansion. This was a potential bug.

I also added a new PassManager API to directly get a function-base analysis:
    getAnalysis(SILFunction *f)

The second change of this commit is the removal of the instruction-index indirection for the cache keys. Now the cache keys directly work on instruction pointers instead of instruction indices. This reduces the number of hash table lookups for a cache lookup from 3 to 1.
This indirection was needed to avoid dangling instruction pointers in the cache keys. But this is not needed anymore, because of the new delayed instruction deletion mechanism.
2021-05-26 21:57:54 +02:00

93 lines
3.2 KiB
C++

//===--- ARCLoopOpts.cpp --------------------------------------------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
///
/// \file
///
/// This is a pass that runs multiple interrelated loop passes on a function. It
/// also provides caching of certain analysis information that is used by all of
/// the passes.
///
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "arc-sequence-opts"
#include "swift/SILOptimizer/PassManager/Passes.h"
#include "ARCSequenceOpts.h"
#include "swift/SILOptimizer/Analysis/AliasAnalysis.h"
#include "swift/SILOptimizer/Analysis/DominanceAnalysis.h"
#include "swift/SILOptimizer/Analysis/LoopAnalysis.h"
#include "swift/SILOptimizer/Analysis/LoopRegionAnalysis.h"
#include "swift/SILOptimizer/Analysis/ProgramTerminationAnalysis.h"
#include "swift/SILOptimizer/Analysis/RCIdentityAnalysis.h"
#include "swift/SILOptimizer/PassManager/Transforms.h"
using namespace swift;
//===----------------------------------------------------------------------===//
// Top Level Driver
//===----------------------------------------------------------------------===//
namespace {
class ARCLoopOpts : public SILFunctionTransform {
void run() override {
auto *F = getFunction();
// If ARC optimizations are disabled, don't optimize anything and bail.
if (!getOptions().EnableARCOptimizations)
return;
// Skip global init functions.
if (F->isGlobalInitOnceFunction())
return;
auto *LA = getAnalysis<SILLoopAnalysis>();
auto *LI = LA->get(F);
auto *DA = getAnalysis<DominanceAnalysis>();
auto *DI = DA->get(F);
// Canonicalize the loops, invalidating if we need to.
if (canonicalizeAllLoops(DI, LI)) {
// We preserve loop info and the dominator tree.
DA->lockInvalidation();
LA->lockInvalidation();
PM->invalidateAnalysis(F, SILAnalysis::InvalidationKind::FunctionBody);
DA->unlockInvalidation();
LA->unlockInvalidation();
}
// Get all of the analyses that we need.
auto *AA = getAnalysis<AliasAnalysis>(F);
auto *RCFI = getAnalysis<RCIdentityAnalysis>()->get(F);
auto *EAFI = getAnalysis<EpilogueARCAnalysis>()->get(F);
auto *LRFI = getAnalysis<LoopRegionAnalysis>()->get(F);
ProgramTerminationFunctionInfo PTFI(F);
// Create all of our visitors, register them with the visitor group, and
// run.
LoopARCPairingContext LoopARCContext(*F, AA, LRFI, LI, RCFI, EAFI, &PTFI);
SILLoopVisitorGroup VisitorGroup(F, LI);
VisitorGroup.addVisitor(&LoopARCContext);
VisitorGroup.run();
if (LoopARCContext.madeChange()) {
invalidateAnalysis(SILAnalysis::InvalidationKind::CallsAndInstructions);
}
}
};
} // end anonymous namespace
SILTransform *swift::createARCLoopOpts() {
return new ARCLoopOpts();
}