[PATCH] D108283: [flang][driver] Add documentation for Plugins

Fri Aug 20 02:51:49 PDT 2021

kiranchandramohan added subscribers: klausler, kiranchandramohan.
kiranchandramohan added a comment.

Can you clarify where the plugins should reside? I am guessing that the examples directory is just for examples. Is it in tools? Or can it be anywhere including out of tree?

In Flang the frontend consists of a parse-tree as well as a high-level IR. For clarity should we specify that this is for Parse Tree plugins? Should we further clarify that we are enabling the plugins after semantic checks?

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Comment at: flang/docs/FlangDriver.md:289
+## Creating the Plugin
+The two parts required for Plugins to work are:
+1. A main class that inherits from `PluginParseTreeAction`
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awarzynski wrote:
> I would expand this into 3 parts (copying code from https://reviews.llvm.org/D107089, every item is one part):
> * `class PrintFunctionNamesAction : public PluginParseTreeAction` that wraps everything together and represents the frontend action class corresponding to your plugin
> * `PrintFunctionNamesAction::ExecuteAction` that implements the actual action (i.e. **what** it does)
> * `static FrontendPluginRegistry::Add<PrintFunctionNamesAction> X` that registers the plugin
> 
> It would also be worthwhile to mention `struct ParseTreeVisitor` (and `Pre` and `Post` methods). No need to go into too much detail - you can provide links to the relevant docs/implementation.
As @awarzynski says it will be beneficial to mention the mechanism used to traverse the parse-tree. The clang plugins page calls out the RecursiveAstVisitor.
https://clang.llvm.org/docs/ClangPlugins.html#introduction

Since this is the API (Visitor class with Pre and Post functions) that we are exposing for traversing, it will also be good to get approval from @klausler.

Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D108283/new/

https://reviews.llvm.org/D108283