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017ee7bf04
We were not using the primary benefits of an intrusive list, namely the ability to insert or remove from the middle of the list, so let's switch to a plain vector. This also avoids linked-list pointer chasing.
73 lines
2.2 KiB
C++
73 lines
2.2 KiB
C++
//===--- PruneVTables.cpp - Prune unnecessary vtable entries --------------===//
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//
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// This source file is part of the Swift.org open source project
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//
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// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
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// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See https://swift.org/LICENSE.txt for license information
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// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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//
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// Mark sil_vtable entries as [nonoverridden] when possible, so that we know
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// at IRGen time they can be elided from runtime vtables.
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//
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//===----------------------------------------------------------------------===//
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#define DEBUG_TYPE "prune-vtables"
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#include "swift/SILOptimizer/PassManager/Transforms.h"
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#include "swift/SILOptimizer/Utils/InstOptUtils.h"
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using namespace swift;
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namespace {
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class PruneVTables : public SILModuleTransform {
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void runOnVTable(SILModule *M,
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SILVTable *vtable) {
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for (auto &entry : vtable->getMutableEntries()) {
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// We don't need to worry about entries that are inherited, overridden,
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// or have already been found to have no overrides.
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if (entry.TheKind != SILVTable::Entry::Normal) {
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continue;
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}
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// The destructor entry must remain.
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if (entry.Method.kind == SILDeclRef::Kind::Deallocator) {
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continue;
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}
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auto methodDecl = entry.Method.getAbstractFunctionDecl();
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if (!methodDecl)
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continue;
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// Is the method declared final?
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if (!methodDecl->isFinal()) {
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// Are callees of this entry statically knowable?
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if (!calleesAreStaticallyKnowable(*M, entry.Method))
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continue;
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// Does the method have any overrides in this module?
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if (methodDecl->isOverridden())
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continue;
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}
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entry.TheKind = SILVTable::Entry::NormalNonOverridden;
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}
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}
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void run() override {
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SILModule *M = getModule();
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for (auto &vtable : M->getVTables()) {
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runOnVTable(M, vtable);
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}
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}
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};
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}
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SILTransform *swift::createPruneVTables() {
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return new PruneVTables();
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}
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