Emit MLIR from c++/c

MLIR
1

Hi there, I am pretty new to MLIR. I noticed that the toy dialect example can emit mlir using Toy DSL and a codegen tool. Otherwise, we can also use MLIR python-binding to build MLIR module and op flow and emit MLIR by running the python code.

I wonder how to Emit MLIR from C/C++, is there any example? I try my best to find the examples but found none.

Thanks in advance!

2

Hey,

The largest range of examples there would be the passes. What most of the passes do is use C++ builders (along wit matching section and defining passes, but the most is constructing MLIR operations in C++ which is how you’ll build the module before emitting it). The unittest group is another.

Best,

Jacques

1 Like
3

Toy is written in C++ as well: it generates MLIR in C++ from the parsed-tree for the small DSL it is using.

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4

Thanks, Jacques , I think you save my life

5

Yes, thanks mehdi, you are right, but it is hard for me to write a DSL. I think the python binding is a good way. But I wonder if there is C++ binding, may be it is the way that Jacques describe that constructing MLIR op in C++ passes.

6

I don’t quite get your question actually, you don’t have to write a DSL: the DSL in Toy is just to support the tutorial. The parser of the DSL produces a parse tree, which is a C++ data structure, you could have this from JSON or any other source. The fact is that the “C++ bindings” as you call it what is used in Toy to emit MLIR: this is the exact same API you will find in c++ passes as Jacques describe. The difference is that Toy will emit MLIR “from scratch” (that is you have as input a C++ data structure that you turn into MLIR) whereas the C++ passes are transforming an existing MLIR construct in place.

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@mehdi_amini Thanks mehdi, I got your point. Do I have to write the operation building codes in passes? Is there a way for me to write MLIR op building codes in a standalone c++ file just like I do using python bindings or that in Toy DSL?

8

I may miss something, but isn’t the answer in the question? Yes you can do just like the Toy example, that’s why it’s there: to show how you can do it.

9

Thanks for your patience, after read more code in Toy chapter2, I know how to do now.

10

hi，@ColdCodeCool
I,m also interested it, would you like show the link of above Toy example ?

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Sure, you can refer to this Link. It is not that intuitive like python binding does to build a module.