C++ 20 脚手架

发表于 更新于

安装依赖软件

MacOS

Homebrew 上的软件版本比较新，可以直接安装。

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brew install cmake ninja llvm clang-format

Linux

  1. CMake 和 Ninja 的最佳安装方式是 pip
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pip install cmake ninja
  1. 最新版的 LLVM 可以通过 PPA 安装
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# 信任证书
wget -qO- https://apt.llvm.org/llvm-snapshot.gpg.key \
    | sudo tee /etc/apt/trusted.gpg.d/apt.llvm.org.asc

# 添加 nightly 源
echo "deb http://apt.llvm.org/buster/ llvm-toolchain-buster main" \
    | sudo tee /etc/apt/sources.list.d/llvm.list

# 安装包
sudo apt update
sudo apt install llvm clang clangd clang-tidy clang-format

项目结构

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├── CMakeLists.txt
├── README.md
├── doc
│   └── README.md
├── include
│   └── common.h
├── src
│   ├── bar.cpp
│   └── foo.cpp
└── test
    ├── bar_test.cpp
    ├── foo_test.cpp
    ├── resource
    │   └── dict.txt
    └── test.cpp

测试代码

  1. 功能代码 

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    // src/foo.cpp
    int foo(int x) {
        return x + x;
    }

  2. 测试代码 

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    // test/foo_test.cpp
    extern int foo(int x);
    #include <catch2/catch_test_macros.hpp>

    TEST_CASE("Foo") {
        REQUIRE(foo(2) == 4);
    }

  3. 测试入口 

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    // test/test.cpp
    #define CATCH_CONFIG_RUNNER
    #include <catch2/catch_test_macros.hpp>

构建脚本

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# 3.28 版本开始支持 Modules
cmake_minimum_required(VERSION 3.28)
# 项目名称
project(cpp20)

set(CMAKE_CXX_STANDARD 20)
set(CMAKE_CXX_STANDARD_REQUIRED ON)

# 头文件目录
include_directories(${CMAKE_CURRENT_SOURCE_DIR}/include)
# 功能代码
file(GLOB_RECURSE CPP_FILES ${PROJECT_SOURCE_DIR}/src/*.cpp)
# 测试代码
file(GLOB_RECURSE TEST_FILES ${PROJECT_SOURCE_DIR}/test/*.cpp)

# Catch2 测试框架
Include(FetchContent)
FetchContent_Declare(
    Catch2 GIT_REPOSITORY https://github.com/catchorg/Catch2.git
    GIT_TAG        v3.5.0 # or a later release
)
FetchContent_MakeAvailable(Catch2)

# 测试程序
add_executable(tests ${CPP_FILES} ${TEST_FILES})
target_link_libraries(tests PRIVATE
    Catch2::Catch2WithMain)

set_property(TARGET tests PROPERTY CXX_STANDARD 20)

# 定义宏
target_compile_definitions(tests PRIVATE 
    TEST_RESOURCE_DIR="${CMAKE_CURRENT_SOURCE_DIR}/test/resource")

# 一些有用的告警选项
target_compile_options(tests PRIVATE
    -Wall
    -Wextra
    -pedantic
    -Werror
    -Wno-unused-parameter
    -Wno-unused-variable
    -Wno-unused-but-set-variable
    -Wno-unused-function
    -Wno-unused-but-set-parameter
    -Wno-unused-result
    -Wno-unused-value
    -Wno-unused-local-typedefs
    -ftrapv)

include(CTest)
include(Catch)
catch_discover_tests(tests)

# 代码检查
find_program(CLANG_TIDY_EXE NAMES "clang-tidy" REQUIRED)
set(CLANG_TIDY_COMMAND "${CLANG_TIDY_EXE}" "--format-style=llvm")
set_target_properties(tests PROPERTIES CXX_CLANG_TIDY "${CLANG_TIDY_COMMAND}")

构建步骤

  1. CMake 构建
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cmake -B build \
    -DCMAKE_BUILD_TYPE=Debug \
    -DCMAKE_CXX_FLAGS="-fprofile-instr-generate -fcoverage-mapping" \
    -DCMAKE_C_FLAGS="-fprofile-instr-generate -fcoverage-mapping" \
    -DCMAKE_CXX_COMPILER=clang++ \
    -DCMAKE_C_COMPILER=clang \
    -DCMAKE_EXPORT_COMPILE_COMMANDS=yes \
    -G Ninja

cmake --build build --config Debug
  1. 运行测试
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cd build
LLVM_PROFILE_FILE="default.profraw" ./tests
  1. 覆盖率分析
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llvm-profdata merge -sparse default.profraw -o default.profdata

llvm-cov show ./tests \
    -ignore-filename-regex="build/|include/|test/" \
    -instr-profile=default.profdata \
    -format=html \
    -output-dir=cov-html

# 覆盖率报告
open cov-html/index.html