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[Exclusivity] Sink may release release instructions out of access scopes #20201
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124 changes: 124 additions & 0 deletions
124
lib/SILOptimizer/Transforms/AccessEnforcementReleaseSinking.cpp
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,124 @@ | ||
| //===--- AccessEnforcementReleaseSinking.cpp - release sinking opt ---===// | ||
| // | ||
| // This source file is part of the Swift.org open source project | ||
| // | ||
| // Copyright (c) 2014 - 2018 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 | ||
| // | ||
| //===----------------------------------------------------------------------===// | ||
| /// | ||
| /// This function pass sinks releases out of access scopes. | ||
| /// | ||
| /// General case: | ||
| /// begin_access A | ||
| /// ... | ||
| /// strong_release / release_value / destroy | ||
| /// end_access | ||
| /// | ||
| /// The release instruction can be sunk below the end_access instruction, | ||
| /// This extends the lifetime of the released value, but, might allow us to | ||
| /// Mark the access scope as no nested conflict. | ||
| //===----------------------------------------------------------------------===// | ||
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| #define DEBUG_TYPE "access-enforcement-release" | ||
|
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| #include "swift/SIL/ApplySite.h" | ||
| #include "swift/SIL/DebugUtils.h" | ||
| #include "swift/SIL/SILFunction.h" | ||
| #include "swift/SILOptimizer/PassManager/Transforms.h" | ||
|
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| using namespace swift; | ||
|
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| // Returns a bool: If this is a "sinkable" instruction type for this opt | ||
| static bool isSinkable(SILInstruction &inst) { | ||
| switch (inst.getKind()) { | ||
| default: | ||
| return false; | ||
| case SILInstructionKind::DestroyValueInst: | ||
| case SILInstructionKind::ReleaseValueInst: | ||
| case SILInstructionKind::ReleaseValueAddrInst: | ||
| case SILInstructionKind::StrongReleaseInst: | ||
| case SILInstructionKind::UnmanagedReleaseValueInst: | ||
| return true; | ||
| } | ||
| } | ||
|
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| // Returns a bool: If this is a "barrier" instruction for this opt | ||
| static bool isBarrier(SILInstruction &inst) { | ||
| switch (inst.getKind()) { | ||
| default: | ||
| return FullApplySite::isa(&inst) != FullApplySite(); | ||
| case SILInstructionKind::BeginAccessInst: | ||
| case SILInstructionKind::BeginUnpairedAccessInst: | ||
| case SILInstructionKind::IsUniqueInst: | ||
| return true; | ||
| } | ||
| } | ||
|
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| // Processes a block bottom-up, keeping a lookout for end_access instructions | ||
| // If we encounter a "barrier" we clear out the current end_access | ||
| // If we encounter a "release", and we have a current end_access, we sink it | ||
| static void processBlock(SILBasicBlock &block) { | ||
| EndAccessInst *bottomEndAccessInst = nullptr; | ||
| for (auto reverseIt = block.rbegin(); reverseIt != block.rend(); | ||
| ++reverseIt) { | ||
| SILInstruction &currIns = *reverseIt; | ||
| if (auto *currEAI = dyn_cast<EndAccessInst>(&currIns)) { | ||
| if (!bottomEndAccessInst) { | ||
| bottomEndAccessInst = currEAI; | ||
| } | ||
| } else if (isBarrier(currIns)) { | ||
| LLVM_DEBUG(llvm::dbgs() << "Found a barrier " << currIns | ||
| << ", clearing last seen end_access\n"); | ||
| bottomEndAccessInst = nullptr; | ||
| } else if (isSinkable(currIns)) { | ||
| LLVM_DEBUG(llvm::dbgs() | ||
| << "Found a sinkable instruction " << currIns << "\n"); | ||
| if (!bottomEndAccessInst) { | ||
| LLVM_DEBUG( | ||
| llvm::dbgs() | ||
| << "Cannot be sunk: no open barrier-less end_access found\n"); | ||
| continue; | ||
| } | ||
| LLVM_DEBUG(llvm::dbgs() << "Moving sinkable instruction below " | ||
| << *bottomEndAccessInst << "\n"); | ||
| // We need to avoid iterator invalidation: | ||
| // We know this is not the last instruction of the block: | ||
| // 1) not a TermInst | ||
| // 2) bottomEndAccessInst != nil | ||
| assert(reverseIt != block.rbegin() && | ||
| "Did not expect a sinkable instruction at block's end"); | ||
| // Go back to previous iteration | ||
| auto prevIt = reverseIt; | ||
| --prevIt; | ||
| // Move the instruction after the end_access | ||
| currIns.moveAfter(bottomEndAccessInst); | ||
| // make reverseIt into a valid iterator again | ||
| reverseIt = prevIt; | ||
| } | ||
| } | ||
| } | ||
|
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||
| namespace { | ||
| struct AccessEnforcementReleaseSinking : public SILFunctionTransform { | ||
| void run() override { | ||
| SILFunction *F = getFunction(); | ||
| if (F->empty()) | ||
| return; | ||
|
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| LLVM_DEBUG(llvm::dbgs() << "Running AccessEnforcementReleaseSinking on " | ||
| << F->getName() << "\n"); | ||
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| for (SILBasicBlock &currBB : *F) { | ||
| processBlock(currBB); | ||
| } | ||
| } | ||
| }; | ||
| } // namespace | ||
|
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| SILTransform *swift::createAccessEnforcementReleaseSinking() { | ||
| return new AccessEnforcementReleaseSinking(); | ||
| } | ||
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,217 @@ | ||
| // RUN: %target-sil-opt -access-enforcement-release -assume-parsing-unqualified-ownership-sil %s -enable-sil-verify-all | %FileCheck %s | ||
| // | ||
| // Test the AccessEnforcementReleaseSinking pass in isolation. | ||
| // This ensures that no upstream passes have removed SIL-level access markers | ||
| // that are required to ensure the pass is not overly optimistic. | ||
|
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| sil_stage canonical | ||
|
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| import Builtin | ||
| import Swift | ||
| import SwiftShims | ||
|
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||
| struct X { | ||
| @sil_stored var i: Int64 { get set } | ||
| init(i: Int64) | ||
| init() | ||
| } | ||
|
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| var globalX: X | ||
|
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| sil_global hidden @globalX : $X | ||
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| sil hidden_external [global_init] @globalAddressor : $@convention(thin) () -> Builtin.RawPointer | ||
|
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| // public func testSimpleRelease() { | ||
| // Checks the simple case of release sinking | ||
| // | ||
| // CHECK-LABEL: sil @testSimpleRelease : $@convention(thin) () -> () { | ||
| // CHECK: [[GLOBAL:%.*]] = global_addr @globalX : $*X | ||
| // CHECK-NEXT: [[BEGIN:%.*]] = begin_access [modify] [dynamic] [[GLOBAL]] : $*X | ||
| // CHECK-NEXT: [[LOADED:%.*]] = load [[BEGIN]] : $*X | ||
| // CHECK-NEXT: end_access [[BEGIN]] : $*X | ||
| // CHECK-NEXT: release_value [[LOADED]] | ||
| // CHECK-LABEL: } // end sil function 'testSimpleRelease' | ||
| sil @testSimpleRelease : $@convention(thin) () -> () { | ||
| bb0: | ||
| %0 = global_addr @globalX: $*X | ||
| %1 = begin_access [modify] [dynamic] %0 : $*X | ||
| %2 = load %1 : $*X | ||
| release_value %2 : $X | ||
| end_access %1 : $*X | ||
| %ret = tuple () | ||
| return %ret : $() | ||
| } | ||
|
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| // public func testMultiBlocklSimpleRelease() { | ||
| // Checks the simple case of release sinking with the begin_access in a different block | ||
| // | ||
| // CHECK-LABEL: sil @testMultiBlocklSimpleRelease : $@convention(thin) () -> () { | ||
| // CHECK: [[GLOBAL:%.*]] = global_addr @globalX : $*X | ||
| // CHECK-NEXT: [[BEGIN:%.*]] = begin_access [modify] [dynamic] [[GLOBAL]] : $*X | ||
| // CHECK-NEXT: [[LOADED:%.*]] = load [[BEGIN]] : $*X | ||
| // CHECK-NEXT: br bb1 | ||
| // CHECK: bb1 | ||
| // CHECK-NEXT: end_access [[BEGIN]] : $*X | ||
| // CHECK-NEXT: release_value [[LOADED]] | ||
| // CHECK-LABEL: } // end sil function 'testMultiBlocklSimpleRelease' | ||
| sil @testMultiBlocklSimpleRelease : $@convention(thin) () -> () { | ||
| bb0: | ||
| %0 = global_addr @globalX: $*X | ||
| %1 = begin_access [modify] [dynamic] %0 : $*X | ||
| %2 = load %1 : $*X | ||
| br bb1 | ||
|
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||
| bb1: | ||
| release_value %2 : $X | ||
| end_access %1 : $*X | ||
| %ret = tuple () | ||
| return %ret : $() | ||
| } | ||
|
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| // public func testMultiBlocklBailOnRelease() { | ||
| // Checks bailing (for now) on the simple case due to the release being in a different block | ||
| // | ||
| // CHECK-LABEL: sil @testMultiBlocklBailOnRelease : $@convention(thin) () -> () { | ||
| // CHECK: [[GLOBAL:%.*]] = global_addr @globalX : $*X | ||
| // CHECK-NEXT: [[BEGIN:%.*]] = begin_access [modify] [dynamic] [[GLOBAL]] : $*X | ||
| // CHECK-NEXT: [[LOADED:%.*]] = load [[BEGIN]] : $*X | ||
| // CHECK-NEXT: release_value [[LOADED]] | ||
| // CHECK-NEXT: br bb1 | ||
| // CHECK: bb1 | ||
| // CHECK-NEXT: end_access [[BEGIN]] : $*X | ||
| // CHECK-LABEL: } // end sil function 'testMultiBlocklBailOnRelease' | ||
| sil @testMultiBlocklBailOnRelease : $@convention(thin) () -> () { | ||
| bb0: | ||
| %0 = global_addr @globalX: $*X | ||
| %1 = begin_access [modify] [dynamic] %0 : $*X | ||
| %2 = load %1 : $*X | ||
| release_value %2 : $X | ||
| br bb1 | ||
|
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||
| bb1: | ||
| end_access %1 : $*X | ||
| %ret = tuple () | ||
| return %ret : $() | ||
| } | ||
|
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| // public func testApplyBarrier() { | ||
| // Checks we don't sink across apply-site barrier | ||
| // | ||
| // CHECK-LABEL: sil @testApplyBarrier : $@convention(thin) () -> () { | ||
| // CHECK: [[GLOBAL:%.*]] = global_addr @globalX : $*X | ||
| // CHECK-NEXT: [[BEGIN:%.*]] = begin_access [modify] [dynamic] [[GLOBAL]] : $*X | ||
| // CHECK-NEXT: [[LOADED:%.*]] = load [[BEGIN]] : $*X | ||
| // CHECK-NEXT: release_value [[LOADED]] | ||
| // CHECK: apply | ||
| // CHECK-NEXT: end_access [[BEGIN]] : $*X | ||
| // CHECK-LABEL: } // end sil function 'testApplyBarrier' | ||
| sil @testApplyBarrier : $@convention(thin) () -> () { | ||
| bb0: | ||
| %0 = global_addr @globalX: $*X | ||
| %1 = begin_access [modify] [dynamic] %0 : $*X | ||
| %2 = load %1 : $*X | ||
| release_value %2 : $X | ||
| %u0 = function_ref @globalAddressor : $@convention(thin) () -> Builtin.RawPointer | ||
| %u1 = apply %u0() : $@convention(thin) () -> Builtin.RawPointer | ||
| end_access %1 : $*X | ||
| %ret = tuple () | ||
| return %ret : $() | ||
| } | ||
|
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||
| // public func testUniquenessBarrier() { | ||
| // Checks we don't sink across a uniqueness check | ||
| // | ||
| // CHECK-LABEL: sil @testUniquenessBarrier : $@convention(thin) () -> () { | ||
| // CHECK: [[GLOBAL:%.*]] = global_addr @globalX : $*X | ||
| // CHECK-NEXT: [[BEGIN:%.*]] = begin_access [modify] [dynamic] [[GLOBAL]] : $*X | ||
| // CHECK-NEXT: [[LOADED:%.*]] = load [[BEGIN]] : $*X | ||
| // CHECK-NEXT: release_value [[LOADED]] | ||
| // CHECK-NEXT: is_unique | ||
| // CHECK-NEXT: end_access [[BEGIN]] : $*X | ||
| // CHECK-LABEL: } // end sil function 'testUniquenessBarrier' | ||
| sil @testUniquenessBarrier : $@convention(thin) () -> () { | ||
| bb0: | ||
| %0 = global_addr @globalX: $*X | ||
| %1 = begin_access [modify] [dynamic] %0 : $*X | ||
| %2 = load %1 : $*X | ||
| release_value %2 : $X | ||
| is_unique %1 : $*X | ||
| end_access %1 : $*X | ||
| %ret = tuple () | ||
| return %ret : $() | ||
| } | ||
|
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| // public func testBeginBarrier() { | ||
| // Checks we don't sink across begin_access barrier | ||
| // | ||
| // CHECK-LABEL: sil @testBeginBarrier : $@convention(thin) () -> () { | ||
| // CHECK: [[GLOBAL:%.*]] = global_addr @globalX : $*X | ||
| // CHECK-NEXT: [[BEGIN:%.*]] = begin_access [modify] [dynamic] [[GLOBAL]] : $*X | ||
| // CHECK-NEXT: [[LOADED:%.*]] = load [[BEGIN]] : $*X | ||
| // CHECK-NEXT: release_value [[LOADED]] | ||
| // CHECK-NEXT: [[BEGIN2:%.*]] = begin_access [modify] [dynamic] [[GLOBAL]] : $*X | ||
| // CHECK-NEXT: end_access [[BEGIN2]] : $*X | ||
| // CHECK-NEXT: end_access [[BEGIN]] : $*X | ||
| // CHECK-LABEL: } // end sil function 'testBeginBarrier' | ||
| sil @testBeginBarrier : $@convention(thin) () -> () { | ||
| bb0: | ||
| %0 = global_addr @globalX: $*X | ||
| %1 = begin_access [modify] [dynamic] %0 : $*X | ||
| %2 = load %1 : $*X | ||
| release_value %2 : $X | ||
| %b0 = begin_access [modify] [dynamic] %0 : $*X | ||
| end_access %b0 : $*X | ||
| end_access %1 : $*X | ||
| %ret = tuple () | ||
| return %ret : $() | ||
| } | ||
|
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| // public func testSinkCrossMultiEnds() { | ||
| // Checks that we choose the *bottom* end_access when sinking | ||
| // | ||
| // CHECK-LABEL: sil @testSinkCrossMultiEnds : $@convention(thin) () -> () { | ||
| // CHECK: [[GLOBAL:%.*]] = global_addr @globalX : $*X | ||
| // CHECK-NEXT: [[BEGIN:%.*]] = begin_access [modify] [dynamic] [[GLOBAL]] : $*X | ||
| // CHECK-NEXT: [[BEGIN2:%.*]] = begin_access [modify] [dynamic] [[GLOBAL]] : $*X | ||
| // CHECK-NEXT: [[LOADED:%.*]] = load [[BEGIN]] : $*X | ||
| // CHECK-NEXT: end_access [[BEGIN2]] : $*X | ||
| // CHECK-NEXT: end_access [[BEGIN]] : $*X | ||
| // CHECK-NEXT: release_value [[LOADED]] | ||
| // CHECK-LABEL: } // end sil function 'testSinkCrossMultiEnds' | ||
| sil @testSinkCrossMultiEnds : $@convention(thin) () -> () { | ||
| bb0: | ||
| %0 = global_addr @globalX: $*X | ||
| %1 = begin_access [modify] [dynamic] %0 : $*X | ||
| %b0 = begin_access [modify] [dynamic] %0 : $*X | ||
| %2 = load %1 : $*X | ||
| release_value %2 : $X | ||
| end_access %b0 : $*X | ||
| end_access %1 : $*X | ||
| %ret = tuple () | ||
| return %ret : $() | ||
| } | ||
|
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| // public func testSinkAfterBarrierEncounter() { | ||
| // Checks that we sink after barrier resetting | ||
| // | ||
| // CHECK-LABEL: sil @testSinkAfterBarrierEncounter : $@convention(thin) () -> () { | ||
| // CHECK: [[GLOBAL:%.*]] = global_addr @globalX : $*X | ||
| // CHECK-NEXT: [[BEGIN:%.*]] = begin_access [modify] [dynamic] [[GLOBAL]] : $*X | ||
| // CHECK-NEXT: [[LOADED:%.*]] = load [[BEGIN]] : $*X | ||
| // CHECK-NEXT: end_access [[BEGIN]] : $*X | ||
| // CHECK-NEXT: release_value [[LOADED]] | ||
| // CHECK-NEXT: [[BEGIN2:%.*]] = begin_access [modify] [dynamic] [[GLOBAL]] : $*X | ||
| // CHECK-LABEL: } // end sil function 'testSinkAfterBarrierEncounter' | ||
| sil @testSinkAfterBarrierEncounter : $@convention(thin) () -> () { | ||
| bb0: | ||
| %0 = global_addr @globalX: $*X | ||
| %1 = begin_access [modify] [dynamic] %0 : $*X | ||
| %2 = load %1 : $*X | ||
| release_value %2 : $X | ||
| end_access %1 : $*X | ||
| %b0 = begin_access [modify] [dynamic] %0 : $*X | ||
| end_access %b0 : $*X | ||
| %ret = tuple () | ||
| return %ret : $() | ||
| } |
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[nit]
auto prevIt = std::prev(reverseIt)