text: ===================================
  How To Setup Clang Tooling For LLVM
  ===================================
  
  Clang Tooling provides infrastructure to write tools that need syntactic
  and semantic information about a program. This term also relates to a set
  of specific tools using this infrastructure (e.g. ``clang-check``). This
  document provides information on how to set up and use Clang Tooling for
  the LLVM source code.
  
  Introduction
  ============
  
  Clang Tooling needs a compilation database to figure out specific build
  options for each file. Currently it can create a compilation database
  from the ``compile_commands.json`` file, generated by CMake. When
  invoking clang tools, you can either specify a path to a build directory
  using a command line parameter ``-p`` or let Clang Tooling find this
  file in your source tree. In either case you need to configure your
  build using CMake to use clang tools.
  
  Setup Clang Tooling Using CMake and Make
  ========================================
  
  If you intend to use make to build LLVM, you should have CMake 2.8.6 or
  later installed (can be found `here <http://cmake.org>`_).
  
  First, you need to generate Makefiles for LLVM with CMake. You need to
  make a build directory and run CMake from it:
  
  .. code-block:: console
  
    $ mkdir your/build/directory
    $ cd your/build/directory
    $ cmake -DCMAKE_EXPORT_COMPILE_COMMANDS=ON path/to/llvm/sources
  
  If you want to use clang instead of GCC, you can add
  ``-DCMAKE_C_COMPILER=/path/to/clang -DCMAKE_CXX_COMPILER=/path/to/clang++``.
  You can also use ``ccmake``, which provides a curses interface to configure
  CMake variables for lazy people.
  
  As a result, the new ``compile_commands.json`` file should appear in the
  current directory. You should link it to the LLVM source tree so that
  Clang Tooling is able to use it:
  
  .. code-block:: console
  
    $ ln -s $PWD/compile_commands.json path/to/llvm/source/
  
  Now you are ready to build and test LLVM using make:
  
  .. code-block:: console
  
    $ make check-all
  
  Using Clang Tools
  =================
  
  After you completed the previous steps, you are ready to run clang tools. If
  you have a recent clang installed, you should have ``clang-check`` in
  ``$PATH``. Try to run it on any ``.cpp`` file inside the LLVM source tree:
  
  .. code-block:: console
  
    $ clang-check tools/clang/lib/Tooling/CompilationDatabase.cpp
  
  If you're using vim, it's convenient to have clang-check integrated. Put
  this into your ``.vimrc``:
  
  ::
  
      function! ClangCheckImpl(cmd)
        if &autowrite | wall | endif
        echo "Running " . a:cmd . " ..."
        let l:output = system(a:cmd)
        cexpr l:output
        cwindow
        let w:quickfix_title = a:cmd
        if v:shell_error != 0
          cc
        endif
        let g:clang_check_last_cmd = a:cmd
      endfunction
  
      function! ClangCheck()
        let l:filename = expand('%')
        if l:filename =~ '\.\(cpp\|cxx\|cc\|c\)$'
          call ClangCheckImpl("clang-check " . l:filename)
        elseif exists("g:clang_check_last_cmd")
          call ClangCheckImpl(g:clang_check_last_cmd)
        else
          echo "Can't detect file's compilation arguments and no previous clang-check invocation!"
        endif
      endfunction
  
      nmap <silent> <F5> :call ClangCheck()<CR><CR>
  
  When editing a .cpp/.cxx/.cc/.c file, hit F5 to reparse the file. In
  case the current file has a different extension (for example, .h), F5
  will re-run the last clang-check invocation made from this vim instance
  (if any). The output will go into the error window, which is opened
  automatically when clang-check finds errors, and can be re-opened with
  ``:cope``.
  
  Other ``clang-check`` options that can be useful when working with clang
  AST:
  
  * ``-ast-print`` --- Build ASTs and then pretty-print them.
  * ``-ast-dump`` --- Build ASTs and then debug dump them.
  * ``-ast-dump-filter=<string>`` --- Use with ``-ast-dump`` or ``-ast-print`` to
    dump/print only AST declaration nodes having a certain substring in a
    qualified name. Use ``-ast-list`` to list all filterable declaration node
    names.
  * ``-ast-list`` --- Build ASTs and print the list of declaration node qualified
    names.
  
  Examples:
  
  .. code-block:: console
  
    $ clang-check tools/clang/tools/clang-check/ClangCheck.cpp -ast-dump -ast-dump-filter ActionFactory::newASTConsumer
    Processing: tools/clang/tools/clang-check/ClangCheck.cpp.
    Dumping ::ActionFactory::newASTConsumer:
    clang::ASTConsumer *newASTConsumer() (CompoundStmt 0x44da290 </home/alexfh/local/llvm/tools/clang/tools/clang-check/ClangCheck.cpp:64:40, line:72:3>
      (IfStmt 0x44d97c8 <line:65:5, line:66:45>
        <<<NULL>>>
          (ImplicitCastExpr 0x44d96d0 <line:65:9> '_Bool':'_Bool' <UserDefinedConversion>
    ...
    $ clang-check tools/clang/tools/clang-check/ClangCheck.cpp -ast-print -ast-dump-filter ActionFactory::newASTConsumer
    Processing: tools/clang/tools/clang-check/ClangCheck.cpp.
    Printing <anonymous namespace>::ActionFactory::newASTConsumer:
    clang::ASTConsumer *newASTConsumer() {
        if (this->ASTList.operator _Bool())
            return clang::CreateASTDeclNodeLister();
        if (this->ASTDump.operator _Bool())
            return clang::CreateASTDumper(nullptr /*Dump to stdout.*/,
                                          this->ASTDumpFilter);
        if (this->ASTPrint.operator _Bool())
            return clang::CreateASTPrinter(&llvm::outs(), this->ASTDumpFilter);
        return new clang::ASTConsumer();
    }
  
  (Experimental) Using Ninja Build System
  =======================================
  
  Optionally you can use the `Ninja <https://github.com/martine/ninja>`_
  build system instead of make. It is aimed at making your builds faster.
  Currently this step will require building Ninja from sources.
  
  To take advantage of using Clang Tools along with Ninja build you need
  at least CMake 2.8.9.
  
  Clone the Ninja git repository and build Ninja from sources:
  
  .. code-block:: console
  
    $ git clone git://github.com/martine/ninja.git
    $ cd ninja/
    $ ./bootstrap.py
  
  This will result in a single binary ``ninja`` in the current directory.
  It doesn't require installation and can just be copied to any location
  inside ``$PATH``, say ``/usr/local/bin/``:
  
  .. code-block:: console
  
    $ sudo cp ninja /usr/local/bin/
    $ sudo chmod a+rx /usr/local/bin/ninja
  
  After doing all of this, you'll need to generate Ninja build files for
  LLVM with CMake. You need to make a build directory and run CMake from
  it:
  
  .. code-block:: console
  
    $ mkdir your/build/directory
    $ cd your/build/directory
    $ cmake -G Ninja -DCMAKE_EXPORT_COMPILE_COMMANDS=ON path/to/llvm/sources
  
  If you want to use clang instead of GCC, you can add
  ``-DCMAKE_C_COMPILER=/path/to/clang -DCMAKE_CXX_COMPILER=/path/to/clang++``.
  You can also use ``ccmake``, which provides a curses interface to configure
  CMake variables in an interactive manner.
  
  As a result, the new ``compile_commands.json`` file should appear in the
  current directory. You should link it to the LLVM source tree so that
  Clang Tooling is able to use it:
  
  .. code-block:: console
  
    $ ln -s $PWD/compile_commands.json path/to/llvm/source/
  
  Now you are ready to build and test LLVM using Ninja:
  
  .. code-block:: console
  
    $ ninja check-all
  
  Other target names can be used in the same way as with make.
  
  