1 files changed, 45 insertions, 5 deletions
diff --git a/gnu/llvm/tools/clang/docs/ClangPlugins.rst b/gnu/llvm/tools/clang/docs/ClangPlugins.rst
index 9a5bc142130..833f0dd39f7 100644
--- a/gnu/llvm/tools/clang/docs/ClangPlugins.rst
+++ b/gnu/llvm/tools/clang/docs/ClangPlugins.rst
@@ -43,6 +43,26 @@ register a plugin in a library, use ``FrontendPluginRegistry::Add<>``:
 
   static FrontendPluginRegistry::Add<MyPlugin> X("my-plugin-name", "my plugin description");
 
+Defining pragmas
+================
+
+Plugins can also define pragmas by declaring a ``PragmaHandler`` and
+registering it using ``PragmaHandlerRegistry::Add<>``:
+
+.. code-block:: c++
+
+  // Define a pragma handler for #pragma example_pragma
+  class ExamplePragmaHandler : public PragmaHandler {
+  public:
+    ExamplePragmaHandler() : PragmaHandler("example_pragma") { }
+    void HandlePragma(Preprocessor &PP, PragmaIntroducerKind Introducer,
+                      Token &PragmaTok) {
+      // Handle the pragma
+    }
+  };
+
+  static PragmaHandlerRegistry::Add<ExamplePragmaHandler> Y("example_pragma","example pragma description");
+
 Putting it all together
 =======================
 
@@ -54,21 +74,25 @@ the `latest version of PrintFunctionNames.cpp
 Running the plugin
 ==================
 
+
+Using the cc1 command line
+--------------------------
+
 To run a plugin, the dynamic library containing the plugin registry must be
-loaded via the :option:`-load` command line option. This will load all plugins
+loaded via the `-load` command line option. This will load all plugins
 that are registered, and you can select the plugins to run by specifying the
-:option:`-plugin` option. Additional parameters for the plugins can be passed with
-:option:`-plugin-arg-<plugin-name>`.
+`-plugin` option. Additional parameters for the plugins can be passed with
+`-plugin-arg-<plugin-name>`.
 
 Note that those options must reach clang's cc1 process. There are two
 ways to do so:
 
-* Directly call the parsing process by using the :option:`-cc1` option; this
+* Directly call the parsing process by using the `-cc1` option; this
   has the downside of not configuring the default header search paths, so
   you'll need to specify the full system path configuration on the command
   line.
 * Use clang as usual, but prefix all arguments to the cc1 process with
-  :option:`-Xclang`.
+  `-Xclang`.
 
 For example, to run the ``print-function-names`` plugin over a source file in
 clang, first build the plugin, and then call clang with the plugin from the
@@ -88,3 +112,19 @@ source tree:
 Also see the print-function-name plugin example's
 `README <http://llvm.org/viewvc/llvm-project/cfe/trunk/examples/PrintFunctionNames/README.txt?view=markup>`_
 
+
+Using the clang command line
+----------------------------
+
+Using `-fplugin=plugin` on the clang command line passes the plugin
+through as an argument to `-load` on the cc1 command line. If the plugin
+class implements the ``getActionType`` method then the plugin is run
+automatically. For example, to run the plugin automatically after the main AST
+action (i.e. the same as using `-add-plugin`):
+
+.. code-block:: c++
+
+  // Automatically run the plugin after the main AST action
+  PluginASTAction::ActionType getActionType() override {
+    return AddAfterMainAction;
+  }