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Speculative Devirtualizer: Don't speculate _withUnsafeGuaranteedRef c… #8002

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Merged
merged 1 commit into from
Mar 9, 2017
Merged

Speculative Devirtualizer: Don't speculate _withUnsafeGuaranteedRef c… #8002

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11 changes: 11 additions & 0 deletions lib/SILOptimizer/Transforms/SpeculativeDevirtualizer.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -329,6 +329,17 @@ static bool tryToSpeculateTarget(FullApplySite AI,
if (CMI->isVolatile())
return false;

// Don't devirtualize withUnsafeGuaranteed 'self' as this would prevent
// retain/release removal.
// unmanged._withUnsafeGuaranteedRef { $0.method() }
if (auto *TupleExtract = dyn_cast<TupleExtractInst>(CMI->getOperand()))
if (auto *UnsafeGuaranteedSelf =
dyn_cast<BuiltinInst>(TupleExtract->getOperand()))
if (UnsafeGuaranteedSelf->getBuiltinKind() ==
BuiltinValueKind::UnsafeGuaranteed &&
TupleExtract->getFieldNo() == 0)
return false;

// Strip any upcasts off of our 'self' value, potentially leaving us
// with a value whose type is closer (in the class hierarchy) to the
// actual dynamic type.
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20 changes: 20 additions & 0 deletions test/SILOptimizer/devirt_speculative.sil
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Expand Up @@ -2,6 +2,8 @@

sil_stage canonical

import Builtin

@objc class MyNSObject {}
private class Base : MyNSObject {
override init()
Expand Down Expand Up @@ -104,3 +106,21 @@ bb0(%0: $Base2):
// CHECK: checked_cast_br [exact] %0 : $Base2 to $Sub2, bb{{.*}}, bb[[GENCALL:[0-9]+]]
// CHECK: bb[[GENCALL]]{{.*}}:
// CHECK: apply [[METH]]

// Don't devirtualize 'unsafeGuaranteed' self calls.
// CHECK-LABEL: sil @test_unsafeGuaranteed
// CHECK-NOT: check_cast_br
// CHECK: return
sil @test_unsafeGuaranteed : $@convention(thin) (@guaranteed Base2) -> () {
bb0(%0: $Base2):
strong_retain %0 : $Base2
%4 = builtin "unsafeGuaranteed"<Base2>(%0 : $Base2) : $(Base2, Builtin.Int8)
%5 = tuple_extract %4 : $(Base2, Builtin.Int8), 0
%6 = tuple_extract %4 : $(Base2, Builtin.Int8), 1
%1 = class_method %0 : $Base2, #Base2.foo!1 : (Base2) -> () -> (), $@convention(method) (@guaranteed Base2) -> ()
%2 = apply %1(%5) : $@convention(method) (@guaranteed Base2) -> ()
strong_release %5 : $Base2
%16 = builtin "unsafeGuaranteedEnd"(%6 : $Builtin.Int8) : $()
%3 = tuple()
return %3 : $()
}