[lldb][swift] Disable breakpoint filtering by default

[felipepiovezan]

A previous patch had introduced the notion of Language breakpoint filtering when setting line breakpoints. While this is generally a good idea, the swift implementation was motivated by statements like this:

async let x = ...
await foo()
await x

All of these lines have many different breakpoint locations associated with them, creating many pauses while stepping; the intent behind the filtering was to provide a smoother stepping experience.

The implementation filters breakpoints by "funclet" numbers, disabling all but the lowest such funclet. Unfortunately, this fails when the CFG of an async funclet needs to be cloned in non-trivial ways. For example:

func foo(_ argument: Int) async {
  do {
    switch argument {
    case 1:
      try await willthrow(1)
    case 2:
      try await willthrow(2)
    default:
      return
    }
  } catch {
    print("breakhere")
  }
}

The breakpoint in "breakhere" has two funclets associated with it, one when we throw from case 1, one from case 2. Filtering is incorrect in this situation.

This patch disables filtering until we can solve this at a compiler level. While we are disabling this through the TargetProperties setting, which could affect other languages, Swift is the only such language using that setting.

[felipepiovezan]

@swift-ci test

[felipepiovezan]

@swift-ci test

[felipepiovezan]

15:13:42  [5368/5486][ 97%][407.955s] Linking CXX static library lib/libbenchmark_main.a
04:14:55  Cancelling nested steps due to timeout

That's a timeout

[felipepiovezan]

@swift-ci test macos platform

[felipepiovezan]

09:02:22  Timed Out Tests (1):
09:02:22    lldb-api :: lang/swift/private_generic_type/TestSwiftPrivateGenericType.py

Now this timed out... I tested it locally both with and without debug info and it passed.
Trying again.

[felipepiovezan]

@swift-ci test macos platform

[felipepiovezan]

@swift-ci test macos platform