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

41 lines
1.0 KiB
C++

// RUN: rm -rf %t
// RUN: mkdir %t
// RUN: split-file %s %t
//
// RUN: %clang_cc1 -std=c++20 %t/interface.cppm -emit-module-interface \
// RUN: -o %t/m.pcm
// RUN: %clang_cc1 -std=c++20 %t/implementation.cpp -fmodule-file=m=%t/m.pcm \
// RUN: -fsyntax-only -verify
// Test again with reduced BMI.
// RUN: %clang_cc1 -std=c++20 %t/interface.cppm -emit-reduced-module-interface \
// RUN: -o %t/m.pcm
// RUN: %clang_cc1 -std=c++20 %t/implementation.cpp -fmodule-file=m=%t/m.pcm \
// RUN: -fsyntax-only -verify
//--- invisible.h
#pragma once // This breaks things.
const int kInvisibleSymbol = 0;
struct invisible_struct
{};
#define INVISIBLE_DEFINE
//--- visible.h
#include "invisible.h"
const int kSadlyUndeclaredSymbol = kInvisibleSymbol;
using unfortunately_still_invisible_struct = invisible_struct;
#ifndef INVISIBLE_DEFINE
# error "Still not defined."
#endif
//--- interface.cppm
module;
#include "visible.h"
export module m;
//--- implementation.cpp
// expected-no-diagnostics
module;
#include "visible.h"
module m;