llvm-project/clang/test/Modules/redundant-template-default-arg3.cpp
Chuanqi Xu f21ead0675
[C++20] [Modules] [Reduced BMI] Remove unreachable decls GMF in redued BMI (#88359)
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.
2024-04-12 12:51:58 +08:00

127 lines
3.7 KiB
C++

// RUN: rm -rf %t
// RUN: mkdir %t
// RUN: split-file %s %t
//
// RUN: %clang_cc1 -std=c++20 %t/foo.cppm -I%t -emit-module-interface -o %t/foo.pcm
// RUN: %clang_cc1 -fprebuilt-module-path=%t -std=c++20 %t/use.cpp -I%t/. -fsyntax-only -verify
// RUN: %clang_cc1 -std=c++20 %t/foo.cppm -I%t -emit-reduced-module-interface -o %t/foo.pcm
// RUN: %clang_cc1 -fprebuilt-module-path=%t -std=c++20 %t/use.cpp -I%t/. -fsyntax-only -verify
//--- foo.h
template <typename T = int>
T v;
template <int T = 8>
int v2;
template <typename T>
class my_array {};
template <template <typename> typename C = my_array>
int v3;
template <typename T, int *i = nullptr>
T v4;
template <typename T, T *i = nullptr>
T v5;
inline int a = 43;
template <typename T, int *i = &a>
T v6;
inline int b = 43;
template <typename T, T *i = &b>
T v7;
template <int T = (3 > 2)>
int v8;
consteval int getInt() {
return 55;
}
template <int T = getInt()>
int v9;
//--- foo_bad.h
template <typename T = double>
T v;
template <int T = 9>
int v2;
template <typename T>
class others_array {};
template <template <typename> typename C = others_array>
int v3;
static int a;
consteval int *getIntPtr() {
return &a;
}
template <typename T, int *i = getIntPtr()>
T v4;
consteval void *getVoidPtr() {
return &a;
}
template <typename T, T *i = getVoidPtr()>
T v5;
inline int a_ = 43;
template <typename T, int *i = &a_>
T v6;
inline int b_ = 43;
template <typename T, T *i = &b_>
T v7;
template <int T = -1>
int v8;
consteval int getInt2() {
return 55;
}
template <int T = getInt2()>
int v9;
//--- foo.cppm
module;
#include "foo.h"
export module foo;
export using ::v;
export using ::v2;
export using ::my_array;
export using ::v3;
export using ::v4;
export using ::v5;
export using ::v6;
export using ::v7;
export using ::v8;
export using ::v9;
//--- use.cpp
import foo;
#include "foo_bad.h"
// expected-error@foo_bad.h:1 {{template parameter default argument is inconsistent with previous definition}}
// expected-note@foo.h:1 {{previous default template argument defined in module foo.<global>}}
// expected-error@foo_bad.h:4 {{template parameter default argument is inconsistent with previous definition}}
// expected-note@foo.h:4 {{previous default template argument defined in module foo.<global>}}
// expected-error@foo_bad.h:10 {{template parameter default argument is inconsistent with previous definition}}
// expected-note@foo.h:10 {{previous default template argument defined in module foo.<global>}}
// expected-error@foo_bad.h:17 {{template parameter default argument is inconsistent with previous definition}}
// expected-note@foo.h:13 {{previous default template argument defined in module foo.<global>}}
// expected-error@foo_bad.h:23 {{template parameter default argument is inconsistent with previous definition}}
// expected-note@foo.h:16 {{previous default template argument defined in module foo.<global>}}
// expected-error@foo_bad.h:27 {{template parameter default argument is inconsistent with previous definition}}
// expected-note@foo.h:20 {{previous default template argument defined in module foo.<global>}}
// expected-error@foo_bad.h:31 {{template parameter default argument is inconsistent with previous definition}}
// expected-note@foo.h:24 {{previous default template argument defined in module foo.<global>}}
// expected-error@foo_bad.h:34 {{template parameter default argument is inconsistent with previous definition}}
// expected-note@foo.h:27 {{previous default template argument defined in module foo.<global>}}
// expected-error@foo_bad.h:40 {{template parameter default argument is inconsistent with previous definition}}
// expected-note@foo.h:33 {{previous default template argument defined in module foo.<global>}}