CLI Interface

We implement the scair-opt CLI interface for ScaIR.

scair-opt allows the end-user run the framework end-to-end, applying a specified list of passes to the IR contained within the given file, and more! (but mainly this :D)

Let's install it:

~/scair$ ./mill install

Great! Now you should be able to simply run scair-opt.

Let's run it:

When no arguments are specified, scair-opt prompts you to write the IR manually. If you click Ctrl + D, it will parse the input, and print it back out.

~/scair$ scair-opt

If no input is given, it will return an empty program:

builtin.module {
^bb0():
}

However, if you provide it with an input file, as well as a list of passes, the framework will pass the IR, apply the passes, then print the transformed IR back out!

Let's run our example pass from Transformations tutorial.

To refresh ourselves, let's inspect the IR:

~/scair$ cat sample.mlir
%0 = "arith.constant"() <{value = 5}> : () -> i32
%1 = "arith.constant"() <{value = 5}> : () -> i32
%2 = "arith.addi"(%0, %1) : (i32, i32) -> i32
func.call @print(%2) : (i32) -> ()

Now, let's apply our sample-constant-folding-and-dce pass:

~/scair$ scair-opt sample.mlir --passes sample-constant-folding-and-dce
builtin.module {
  %0 = "arith.constant"() <{value = 10}> : () -> i32
  func.call @print(%0) : (i32) -> ()
}

Additionally, there are a number of flags currently available for scair-opt:

• <file> -> the '.mlir' input file.

• --allow-unregistered-dialect -> allows operations not registered in ScaIR to be parsed.

• --skip-verify -> skips the verification stage of the IR.

• --split-input-file -> Note: for testing purposes only - Split input file on // ----- string.

• --parsing-diagnostics -> parsing diagnose mode, i.e parse errors are not fatal for the whole run

• --print-generic -> prints the IR strictly in the generic format.

• --passes -> a comma separated list of passes to apply to the IR.

• --verify-diagnostics -> verification diagnose mode, i.e verification errors are not fatal for the whole run

Footnotes

By default, the scair-opt executable is compiled with the Scala native compiler.

However, we also provide the option to compile the executable with JVM (GraalVM by default) or GraalVM Native Image compiler.

JVM:

~/scair$ ./mill installJVM

Graal Native Image:

~/scair$ ./mill installGraal