f21ead0675
Following of https://github.com/llvm/llvm-project/pull/76930 This follows the idea of "only writes what we writes", which I think is the most natural and efficient way to implement this optimization. We start writing the BMI from the first declaration in module purview instead of the global module fragment, so that everything in the GMF untouched won't be written in the BMI naturally. The exception is, as I said in https://github.com/llvm/llvm-project/pull/76930, when we write a declaration we need to write its decl context, and when we write the decl context, we need to write everything from it. So when we see `std::vector`, we basically need to write everything under namespace std. This violates our intention. To fix this, this patch delays the writing of namespace in the GMF. From my local measurement, the size of the BMI decrease to 90M from 112M for a local modules build. I think this is significant. This feature will be covered under the experimental reduced BMI so that it won't affect any existing users. So I'd like to land this when the CI gets green. Documents will be added seperately.
70 lines
1.6 KiB
C++
70 lines
1.6 KiB
C++
// RUN: rm -fr %t
|
|
// RUN: mkdir %t
|
|
// RUN: split-file %s %t
|
|
//
|
|
// RUN: %clang_cc1 -std=c++20 -emit-module-interface %t/foo.cppm -o %t/foo.pcm
|
|
// RUN: %clang_cc1 -std=c++20 -fprebuilt-module-path=%t %t/Use.cpp -verify -fsyntax-only
|
|
|
|
// RUN: %clang_cc1 -std=c++20 -emit-reduced-module-interface %t/foo.cppm -o %t/foo.pcm
|
|
// RUN: %clang_cc1 -std=c++20 -fprebuilt-module-path=%t %t/Use.cpp -verify -fsyntax-only -DREDUCED
|
|
|
|
//--- foo.cppm
|
|
module;
|
|
# 3 __FILE__ 1 // use the next physical line number here (and below)
|
|
template <typename T>
|
|
void foo() {
|
|
}
|
|
|
|
template <>
|
|
void foo<int>() {
|
|
}
|
|
|
|
template <typename T>
|
|
void foo2() {
|
|
}
|
|
|
|
template <>
|
|
void foo2<int>() {
|
|
}
|
|
|
|
template <typename T>
|
|
void foo3() {
|
|
}
|
|
|
|
template <>
|
|
void foo3<int>();
|
|
|
|
export module foo;
|
|
export using ::foo;
|
|
export using ::foo3;
|
|
|
|
export template <typename T>
|
|
void foo4() {
|
|
}
|
|
|
|
export template <>
|
|
void foo4<int>() {
|
|
}
|
|
|
|
//--- Use.cpp
|
|
import foo;
|
|
void use() {
|
|
foo<short>();
|
|
foo<int>();
|
|
#ifdef REDUCED
|
|
// In reduced BMI, the foo2 template function is optimized out.
|
|
foo2<short>(); // expected-error {{use of undeclared identifier 'foo2'}}
|
|
foo2<int>(); // expected-error {{use of undeclared identifier 'foo2'}}
|
|
#else
|
|
foo2<short>(); // expected-error {{missing '#include'; 'foo2' must be declared before it is used}}
|
|
// expected-note@* {{declaration here is not visible}}
|
|
foo2<int>(); // expected-error {{missing '#include'; 'foo2' must be declared before it is used}}
|
|
// expected-note@* {{declaration here is not visible}}
|
|
#endif
|
|
foo3<short>();
|
|
foo3<int>();
|
|
|
|
foo4<short>();
|
|
foo4<int>();
|
|
}
|