[cfe-dev] Is there a tool that restores a previously saved AST?

[Daniel Albuschat]

Am Montag, 8. Juli 2013 schrieb Douglas Gregor :

>
> On Jul 5, 2013, at 3:28 PM, Daniel Albuschat <d.albuschat at gmail.com<javascript:_e({}, 'cvml', 'd.albuschat at gmail.com');>>
> wrote:
>
> Hi there,
>
> I recently started looking into the Clang project and have to admit that I
> would never have expected it to be that mature. And I really appreciate the
> design decisions that lead to Clang being that re-usable and flexible. I
> think you're doing each and every C++ programmer a great favor and Clang
> will spawn an immense number of awesome tools in the future that we
> previously might not have imagined being possible to implement.
>
> Enough praising, here is my actual question:
> Is there any tool that reads an AST, saves it to some file or database,
> and later is able to *restore* that AST completely (e.g. to be able to
> create LLVM IR from it)? I'm trying to do something similar, so it'd be
> nice to know whether someone did that before.
> The precompiled header implementations should do something like this,
> shouldn't they? Is their AST representation complete, or are they missing
> things like control-flow?
>
>
> Yes to everything. The precompiled header implementation serializes the
> entire AST. You can use clang -cc1’s ‘-emit-ast’ option to emit the
> serialized AST into a “.ast” file, which can then be used to generate LLVM
> IR. It hasn’t been extensively tested, and to my knowledge nobody is doing
> this in a production environment, but the test file
> test/Frontend/ast-codegen.c illustrates how to do it and that it isn’t
> *completely* broken.
>


Thank you for your reply, Doug.

The reason I am interested in restoring and/or building an AST is because I
am thinking about using Clang as the backend for a programming language. It
will obviously be a subset of C++. It would be awesome to use libraries
written in C++ in it. This means, at a minimum,  instantiating
"simple" classes and calling functions. Think of "C++ light" with less
baggage from C and more straightforward Syntax. I am going to evaluate
whether building my own, simpler AST and translating it into the Clang AST
might work.

Do you think that this is feasible, or is it doomed to fail for some
obvious reasons?

Greetings,
Daniel Albuschat
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/cfe-dev/attachments/20130708/1fa7a082/attachment.html>