ccls

ccls is a C/C++/ObjC language server supporting cross references, hierarchies, completion and semantic highlighting.

See wiki/Home for instructions.

Then put these lines to your vimrc:

let g:LanguageClient_serverCommands = {
      \ 'c': ['/path/to/ccls/Release/ccls'],
      \ 'cpp': ['/path/to/ccls/Release/ccls'],
      \ 'objc': ['/path/to/ccls/Release/ccls'],
      \ }

You are all set! Many LSP standard operations textDocument/definition textDocument/references textDocument/hover should work out of the box. You may want to customize some behavior, see:

• wiki/Customization
• wiki/LanguageClient-neovim. It includes a section introducing custom cross references.