[FIRRTL][CAPI] Add more functions for discriminating and querying type

[SpriteOvO]

This PR adds functions:

• for const firrtlTypeIsConst, firrtlTypeGetConstType
• for bit width firrtlTypeGetBitWidth
• for discriminating firrtlTypeIsA{UInt,SInt,Clock,Reset,...}
• for vector firrtlTypeGetVectorElement, firrtlTypeGetVectorNumElements
• for bundle firrtlTypeGetBundleNumFields, firrtlTypeGetBundleFieldByIndex

CC @sequencer, could you check if there are any missing?

[sequencer]

The capi definition basically looks good to me.

[sequencer]

This returns -1, if any of the bundle fields is a flip type

why

[SpriteOvO]

This is the design of

circt/include/circt/Dialect/FIRRTL/FIRRTLTypes.h

Lines 376 to 383 in cd02a73

	// Get the bit width for this type, return None if unknown. Unlike
	// getBitWidthOrSentinel(), this can recursively compute the bitwidth of
	// aggregate types. For bundle and vectors, recursively get the width of each
	// field element and return the total bit width of the aggregate type. This
	// returns None, if any of the bundle fields is a flip type, or ground type with
	// unknown bit width.
	std::optional<int64_t> getBitWidth(FIRRTLBaseType type,
	bool ignoreFlip = false);

But I forgot to present the ignoreFlip parameter in C-API, I should add it as well.

[SpriteOvO]

Updated~

[mikeurbach]

One minor nitpick on the name of the test function, but this looks good to me. Thanks for these new C APIs... it's annoying but this is still the best way to implement them. And thanks for including unit tests!

[mikeurbach]

nit: I think you meant ...AndQueries

[SpriteOvO]

Yeah, right. Fixed

[SpriteOvO]

@mikeurbach Thank you for reviewing this!

[seldridge]

Windows builds are failing with this for a reason that wasn't immediately obvious to me.