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c3ccbde52b
`EscapeInfo` now conforms to the generic protocols defined in `WalkUtils`. This simplifies the implementation a bit, since trivial instructions are handled by `WalkUtils` and `EscapeInfo` only has to handle a subset of instructions inherent to escape information. Passes using `EscapeInfo` are updated accordingly to become visitors that customize the `EscapeInfo` walk.
64 lines
2.4 KiB
Swift
64 lines
2.4 KiB
Swift
//===--- AliasAnalysis.swift - the alias analysis -------------------------===//
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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 - 2021 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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import OptimizerBridging
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import SIL
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struct AliasAnalysis {
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let bridged: BridgedAliasAnalysis
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func mayRead(_ inst: Instruction, fromAddress: Value) -> Bool {
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switch AliasAnalysis_getMemBehavior(bridged, inst.bridged, fromAddress.bridged) {
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case MayReadBehavior, MayReadWriteBehavior, MayHaveSideEffectsBehavior:
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return true
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default:
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return false
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}
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}
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func mayWrite(_ inst: Instruction, toAddress: Value) -> Bool {
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switch AliasAnalysis_getMemBehavior(bridged, inst.bridged, toAddress.bridged) {
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case MayWriteBehavior, MayReadWriteBehavior, MayHaveSideEffectsBehavior:
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return true
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default:
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return false
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}
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}
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func mayReadOrWrite(_ inst: Instruction, address: Value) -> Bool {
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switch AliasAnalysis_getMemBehavior(bridged, inst.bridged, address.bridged) {
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case MayReadBehavior, MayWriteBehavior, MayReadWriteBehavior,
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MayHaveSideEffectsBehavior:
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return true
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default:
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return false
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}
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}
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/// Returns the correct path for address-alias functions.
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static func getPtrOrAddressPath(for value: Value) -> SmallProjectionPath {
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let ty = value.type
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if ty.isAddress {
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// This is the regular case: the path selects any sub-fields of an address.
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return SmallProjectionPath(.anyValueFields)
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}
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// Some optimizations use the address-alias APIs with non-address SIL values.
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// TODO: this is non-intuitive and we should eliminate those API uses.
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if ty.isClass {
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// If the value is a (non-address) reference it means: all addresses within the class instance.
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return SmallProjectionPath(.anyValueFields).push(.anyClassField)
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}
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// Any other non-address value means: all addresses of any referenced class instances within the value.
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return SmallProjectionPath(.anyValueFields).push(.anyClassField).push(.anyValueFields)
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}
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}
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