Chuanqi Xu da00c60dae
[C++20] [Modules] Introduce reduced BMI (#75894)
Close https://github.com/llvm/llvm-project/issues/71034

See

https://discourse.llvm.org/t/rfc-c-20-modules-introduce-thin-bmi-and-decls-hash/74755

This patch introduces reduced BMI, which doesn't contain the definitions
of functions and variables if its definitions won't contribute to the
ABI.

Testing is a big part of the patch. We want to make sure the reduced BMI
contains the same behavior with the existing and relatively stable
fatBMI. This is pretty helpful for further reduction.

The user interfaces part it left to following patches to ease the
reviewing.
2024-03-08 10:12:51 +08:00

61 lines
1.4 KiB
C++

// https://github.com/llvm/llvm-project/issues/59780
//
// RUN: rm -rf %t
// RUN: mkdir %t
// RUN: split-file %s %t
//
// RUN: %clang_cc1 -std=c++20 %t/data.cppm -emit-module-interface -o %t/data.pcm
// RUN: %clang_cc1 -std=c++20 %t/main.cpp -fprebuilt-module-path=%t -fsyntax-only -verify
// RUN: %clang_cc1 -std=c++20 %t/data.cppm -emit-reduced-module-interface -o %t/data.pcm
// RUN: %clang_cc1 -std=c++20 %t/main.cpp -fprebuilt-module-path=%t -fsyntax-only -verify
//--- foo.h
namespace std {
template <class _Tp>
class expected {
public:
expected(_Tp&& __u)
{}
constexpr ~expected()
requires(__is_trivially_destructible(_Tp))
= default;
constexpr ~expected()
requires(!__is_trivially_destructible(_Tp))
{
}
};
template <class _Tp>
class unique_ptr {
public:
unique_ptr(void* __p) {}
~unique_ptr() {}
};
}
//--- data.cppm
module;
#include "foo.h"
export module data;
export namespace std {
using std::unique_ptr;
using std::expected;
}
export std::expected<std::unique_ptr<int>> parse() {
return std::unique_ptr<int>(nullptr);
}
//--- main.cpp
// expected-no-diagnostics
import data;
int main(int argc, const char *argv[]) {
std::expected<std::unique_ptr<int>> result = parse();
}