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SILGen: Fix crash when emitting vtable thunk for a generic subclass of non-generic base class [5.2] #30055

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Merged
merged 1 commit into from
Feb 26, 2020
Merged

SILGen: Fix crash when emitting vtable thunk for a generic subclass of non-generic base class [5.2] #30055

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8 changes: 6 additions & 2 deletions lib/AST/ASTContext.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -4417,10 +4417,14 @@ ASTContext::getOverrideGenericSignature(const ValueDecl *base,
if (derivedClass->getSuperclass().isNull())
return nullptr;

if (baseGenericCtx->getGenericSignature().isNull() ||
derivedGenericCtx->getGenericSignature().isNull())
auto baseGenericSig = baseGenericCtx->getGenericSignature();
auto derivedGenericSig = derivedGenericCtx->getGenericSignature();
if (derivedGenericSig.isNull())
return nullptr;

if (baseGenericSig.isNull())
return derivedGenericSig;

auto baseClassSig = baseClass->getGenericSignature();
auto subMap = derivedClass->getSuperclass()->getContextSubstitutionMap(
derivedClass->getModuleContext(), baseClass);
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17 changes: 17 additions & 0 deletions test/SILGen/vtable_thunks.swift
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Expand Up @@ -228,6 +228,16 @@ class Noot : Aap {
override func map() -> (S?) -> () -> Noot {}
}

// rdar://problem/59669591
class Base {
func returnsOptional() -> Int? { return nil }
}

class Derived<Foo> : Base {
// The thunk here needs to be generic.
override func returnsOptional() -> Int { return 0 }
}

// CHECK-LABEL: sil private [thunk] [ossa] @$s13vtable_thunks3BarC3foo{{[_0-9a-zA-Z]*}}FTV : $@convention(method) (@guaranteed @callee_guaranteed (Int) -> Int, @guaranteed Bar) -> @owned Optional<@callee_guaranteed (Int) -> Int>
// CHECK: [[IMPL:%.*]] = function_ref @$s13vtable_thunks3BarC3foo{{[_0-9a-zA-Z]*}}F
// CHECK: apply [[IMPL]]
Expand Down Expand Up @@ -257,6 +267,8 @@ class Noot : Aap {
// CHECK: [[OUTER:%.*]] = convert_function [[INNER]] : $@callee_guaranteed () -> @owned Noot to $@callee_guaranteed () -> @owned Optional<Aap>
// CHECK: return [[OUTER]]

// CHECK-LABEL: sil private [thunk] [ossa] @$s13vtable_thunks7DerivedC15returnsOptionalSiyFAA4BaseCADSiSgyFTV : $@convention(method) <τ_0_0> (@guaranteed Derived<τ_0_0>) -> Optional<Int> {

// CHECK-LABEL: sil_vtable D {
// CHECK: #B.iuo!1: {{.*}} : @$s13vtable_thunks1D{{[A-Z0-9a-z_]*}}FTV
// CHECK: #B.f!1: {{.*}} : @$s13vtable_thunks1D{{[A-Z0-9a-z_]*}}F
Expand Down Expand Up @@ -321,3 +333,8 @@ class Noot : Aap {
// CHECK-LABEL: sil_vtable NoThrowVariance {
// CHECK: #ThrowVariance.mightThrow!1: {{.*}} : @$s13vtable_thunks{{[A-Z0-9a-z_]*}}F

// CHECK-LABEL: sil_vtable Base {
// CHECK: #Base.returnsOptional!1: (Base) -> () -> Int? : @$s13vtable_thunks4BaseC15returnsOptionalSiSgyF

// CHECK-LABEL: sil_vtable Derived {
// CHECK: #Base.returnsOptional!1: (Base) -> () -> Int? : @$s13vtable_thunks7DerivedC15returnsOptionalSiyFAA4BaseCADSiSgyFTV [override]