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4f5c75a236
This PR makes it possible to instantiate C++ class templates from Swift. Given a C++ header:
```c++
// C++ module `ClassTemplates`
template<class T>
struct MagicWrapper {
T t;
};
struct MagicNumber {};
```
it is now possible to write in Swift:
```swift
import ClassTemplates
func x() -> MagicWrapper<MagicNumber> {
return MagicWrapper<MagicNumber>()
}
```
This is achieved by importing C++ class templates as generic structs, and then when Swift type checker calls `applyGenericArguments` we detect when the generic struct is backed by the C++ class template and call Clang to instantiate the template. In order to make it possible to put class instantiations such as `MagicWrapper<MagicNumber>` into Swift signatures, we have created a new field in `StructDecl` named `TemplateInstantiationType` where the typechecker stores the `BoundGenericType` which we serialize. Deserializer then notices that the `BoundGenericType` is actually a C++ class template and performs the instantiation logic.
Depends on https://github.com/apple/swift/pull/33420.
Progress towards https://bugs.swift.org/browse/SR-13261.
Fixes https://bugs.swift.org/browse/SR-13775.
Co-authored-by: Dmitri Gribenko <gribozavr@gmail.com>
Co-authored-by: Rosica Dejanovska <rosica@google.com>
21 lines
599 B
C++
21 lines
599 B
C++
#ifndef TEST_INTEROP_CXX_TEMPLATES_INPUTS_CLASS_TEMPLATE_INSTANTIATION_ECISTING_SPECIALIZATION_H
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#define TEST_INTEROP_CXX_TEMPLATES_INPUTS_CLASS_TEMPLATE_INSTANTIATION_EXISTING_SPECIALIZATION_H
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struct IntWrapper {
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int value;
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int getValue() const { return value; }
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};
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template<class T>
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struct MagicWrapper {
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T t;
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int getValuePlusArg(int arg) const { return t.getValue() + arg; }
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};
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inline int forceInstantiation() {
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auto t = MagicWrapper<IntWrapper>();
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return t.getValuePlusArg(14);
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}
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#endif // TEST_INTEROP_CXX_TEMPLATES_INPUTS_CLASS_TEMPLATE_INSTANTIATION_EXISTING_SPECIALIZATION_H
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