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Merged
merged 1 commit into from
Aug 1, 2022
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[interop][SwiftToCxx] generics: add support for returning primitive g… #60330

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21 changes: 19 additions & 2 deletions lib/PrintAsClang/PrintClangFunction.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -66,6 +66,8 @@ bool isResilientType(Type t) {
return false;
}

bool isGenericType(Type t) { return t->is<GenericTypeParamType>(); }

bool isKnownCxxType(Type t, PrimitiveTypeMapping &typeMapping) {
return isKnownType(t, typeMapping, OutputLanguageMode::Cxx);
}
Expand Down Expand Up @@ -223,7 +225,12 @@ class CFunctionSignatureTypePrinter
Optional<OptionalTypeKind> optionalKind,
bool isInOutParam) {
// FIXME: handle optionalKind.
// FIXME: handle isInOutParam.
if (typeUseKind == FunctionSignatureTypeUse::ReturnType) {
// generic is always returned indirectly in C signature.
assert(languageMode == OutputLanguageMode::Cxx);
os << genericTpt->getName();
return;
}
if (!isInOutParam)
os << "const ";
if (languageMode == OutputLanguageMode::Cxx) {
Expand Down Expand Up @@ -321,7 +328,7 @@ void DeclAndTypeClangFunctionPrinter::printFunctionSignature(
bool isIndirectReturnType =
kind == FunctionSignatureKind::CFunctionProto &&
!isKnownCType(resultTy, typeMapping) &&
(isResilientType(resultTy) ||
(isResilientType(resultTy) || isGenericType(resultTy) ||
interopContext.getIrABIDetails().shouldReturnIndirectly(resultTy));
if (!isIndirectReturnType) {
OptionalTypeKind retKind;
Expand Down Expand Up @@ -542,6 +549,16 @@ void DeclAndTypeClangFunctionPrinter::printCxxThunkBody(
// indirectly by a pointer.
if (!isKnownCxxType(resultTy, typeMapping) &&
!hasKnownOptionalNullableCxxMapping(resultTy)) {
if (isGenericType(resultTy)) {
// FIXME: Support returning value types.
os << " T returnValue;\n";
std::string returnAddress;
llvm::raw_string_ostream ros(returnAddress);
ros << "reinterpret_cast<void *>(&returnValue)";
printCallToCFunc(/*additionalParam=*/StringRef(ros.str()));
os << ";\n return returnValue;\n";
return;
}
if (auto *decl = resultTy->getNominalOrBoundGenericNominal()) {
if ((isa<StructDecl>(decl) || isa<EnumDecl>(decl))) {
bool isIndirect =
Expand Down
10 changes: 10 additions & 0 deletions test/Interop/SwiftToCxx/generics/generic-function-execution.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -116,5 +116,15 @@ int main() {
assert(x == -13);
assert(y == 42);
}

{
int x = 4;
assert(genericRet(x) == 4);
}

{
double x = -19.75;
assert(genericRet(x) == -19.75);
}
return 0;
}
13 changes: 13 additions & 0 deletions test/Interop/SwiftToCxx/generics/generic-function-in-cxx.swift
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Expand Up @@ -27,9 +27,14 @@ public func genericSwap<T>(_ x: inout T, _ y: inout T) {
y = t
}

public func genericRet<T>(_ x: T) -> T {
return x
}

// CHECK: SWIFT_EXTERN void $s9Functions20genericPrintFunctionyyxlF(const void * _Nonnull x, void * _Nonnull ) SWIFT_NOEXCEPT SWIFT_CALL; // genericPrintFunction(_:)
// CHECK-NEXT: SWIFT_EXTERN void $s9Functions32genericPrintFunctionMultiGenericyySi_xxSiq_tr0_lF(ptrdiff_t x, const void * _Nonnull t1, const void * _Nonnull t1p, ptrdiff_t y, const void * _Nonnull t2, void * _Nonnull , void * _Nonnull ) SWIFT_NOEXCEPT SWIFT_CALL; // genericPrintFunctionMultiGeneric(_:_:_:_:_:)
// CHECK-NEXT: SWIFT_EXTERN void $s9Functions26genericPrintFunctionTwoArgyyx_SitlF(const void * _Nonnull x, ptrdiff_t y, void * _Nonnull ) SWIFT_NOEXCEPT SWIFT_CALL; // genericPrintFunctionTwoArg(_:_:)
// CHECK-NEXT: SWIFT_EXTERN void $s9Functions10genericRetyxxlF(SWIFT_INDIRECT_RESULT void * _Nonnull, const void * _Nonnull x, void * _Nonnull ) SWIFT_NOEXCEPT SWIFT_CALL; // genericRet(_:)
// CHECK-NEXT: SWIFT_EXTERN void $s9Functions11genericSwapyyxz_xztlF(void * _Nonnull x, void * _Nonnull y, void * _Nonnull ) SWIFT_NOEXCEPT SWIFT_CALL; // genericSwap(_:_:)

// CHECK: template<class T>
Expand All @@ -52,6 +57,14 @@ public func genericSwap<T>(_ x: inout T, _ y: inout T) {
// CHECK-NEXT: return _impl::$s9Functions26genericPrintFunctionTwoArgyyx_SitlF(reinterpret_cast<const void *>(&x), y, swift::getTypeMetadata<T>());
// CHECK-NEXT: }

// CHECK: template<class T>
// CHECK-NEXT: requires swift::isUsableInGenericContext<T>
// CHECK-NEXT: inline T genericRet(const T & x) noexcept SWIFT_WARN_UNUSED_RESULT {
// CHECK-NEXT: T returnValue;
// CHECK-NEXT: _impl::$s9Functions10genericRetyxxlF(reinterpret_cast<void *>(&returnValue), reinterpret_cast<const void *>(&x), swift::getTypeMetadata<T>());
// CHECK-NEXT: return returnValue;
// CHECK-NEXT: }

// CHECK: template<class T>
// CHECK-NEXT: requires swift::isUsableInGenericContext<T>
// CHECK-NEXT: inline void genericSwap(T & x, T & y) noexcept {
Expand Down