Vim: extend the semantic analysis function of YCM for the third-party library of C language

Preface

In many Vim Editor's auto completion plug-in ,YouCompleteMe(YCM) It is definitely one of the best plug-ins , But the configuration process is often prohibitive for beginners . After years of tossing by the author , So far, it has basically reached the level of daily use .

If the reader is right YouCompleteMe This plug-in is unfamiliar , It is suggested to first refer to the author's blog Vim: To configure Python and C++ Common plug-ins .

In the use of Vim edit C Family language code , If some third-party libraries are used additionally （ Such as OpenCV）, Will find YCM Resolution failure , Library file not found , Post order automatic association cannot be used . So , This paper combines YCM file , First analyze why YCM In this case, it will fail , Then give the corresponding solution .

YCM Principles of semantic analysis

adopt YCM file [1], To study the YCM The basic principle of semantic analysis of code , as follows ：

• YCM Use clangd Tools （ rely on clang compiler ） Semantic analysis of code , Such as code completion ,GoTo, Code diagnosis, etc . If clangd Unable to parse code , be YCM It cannot provide semantic analysis .

• and clang The compiler needs some columns compile flags To parse the code , The reason why we encounter problems is that the compiler does not find the corresponding compile flags, And then the resolution fails , The phenomenon that the library file cannot be found .

Method

Here, I'll just extract YCM file , as follows ：

Method 1

Option 1: Use a compilation database

• If using CMake, add -DCMAKE_EXPORT_COMPILE_COMMANDS=ON when configuring (or add set( CMAKE_EXPORT_COMPILE_COMMANDS ON ) to CMakeLists.txt) and copy or symlink the generated database to the root of your project.

• If using Ninja, check out the compdb tool (-t compdb) in its docs.

• If using GNU make, check out compiledb or Bear.

• For other build systems, check out .ycm_extra_conf.py below.

According to the above , I often use CMake The way , The operation is as follows ：

1. In the configured CMakeLists.txt To add the following ：

   set( CMAKE_EXPORT_COMPILE_COMMANDS ON )
   

2. cmake once , Edit again

Method 2

Option 2: Provide the flags manually

I don't need this method , Readers may refer to YCM file , See information [1].

summary

This paper analyzes YCM Yes C The principle of semantic analysis of Family Languages , It's solved Vim Editor use C++ Third party Library （ With OpenCV For example ）YCM Resolution failure , The library file cannot be found .

Reference material

1. YCM C-family Semantic Completion