Strip comments from inlinable text when printing in swiftinterface files

[harlanhaskins]

This adds support in InlinableText.cpp for ignoring the ranges of comment tokens and stripping comments from swiftinterface files. Ideally we'd be able to use SwiftSyntax to read in these source ranges and just reprint them while skipping comment trivia, but that infrastructure isn't quite there yet.

Resolves rdar://44318472

[harlanhaskins]

@swift-ci please smoke test

[ahoppen]

I’ve got another fun counterexample for you. The following is valid but if you remove the block comment, it becomes invalid.

let x = 1 /*
*/ let b = 2

Accidentally selected approve

[ahoppen]

@rintaro Could you also check this, in particular if you have any performance concerns?

[ahoppen]

LGTM

[harlanhaskins]

For full context, this code:

@inlinable
public func hasComments() -> Bool {
  /* comment! */ // comment!
  #if NOT_PROVIDED
    // comment!
    return true
  #endif

  print(/* 
    comment! 
  */"this should show up")

  print(
    // comment! don't mess up indentation!
    """
    """)

  #if compiler(>=5.3) // comment!
  print(/*comment!*/"")
  #endif

  let x = 1/*
  */let y = 2

  let a = 3
  /* test */let b = 2

  #sourceLocation(file: "if-configs.swift", line: 200)

  #if !NOT_PROVIDED
    // comment!
    return/* comment! */true/* comment! */
  #endif
}

Will be written to a swiftinterface as:

@inlinable public func hasComments() -> Bool {
     

  print(
"this should show up")

  print(
     
    """
    """)

  #if compiler(>=5.3)  
  print( "")
  #endif

  let x = 1
let y = 2

  let a = 3
   let b = 2

  

     
    return true 
}

And bodies without comments pass through unchanged.

[harlanhaskins]

@swift-ci please smoke test

[rintaro]

Unrelated to this PR, but I realized current ExtractInactiveRanges doesn't/can't support #if for member expressions or attributes (and more if we expand the feature to others) 😢

[harlanhaskins]

@rintaro Uhhh, that's not great! We didn't support them when this code was originally written so it definitely needs to be updated. That's a secrecy concern.

[rintaro]

@harlanhaskins The problem is that AST doesn't have those information. We don't model #if for member expressions in AST. Longer term plan is to migrate it to swift-syntax and SwiftIfConfig But before that, we need to find a workaround somehow.

[harlanhaskins]

I would be totally happy with ExtractInlinableText being fully rewritten in SwiftSyntax. That would be really nice.