Add source annotation to SILPrinter under flag -sil-print-sourceinfo

[meg-gupta]

This flag will add source annotation in SIL.
rdar://58365252

[meg-gupta]

Will look something like this:

bb34:                                             // Preds: bb19
  //     sum += ele.id;
  %364 = class_method %250 : $eletype, #eletype.id!getter.1 : (eletype) -> () -> Int, $@convention(method) (@guaranteed eletype) -> Int // user: %366
  strong_retain %250 : $eletype   

[atrick]

Awesome. I have a couple suggestions, but otherwise looks good.

[atrick]

Can you handle the case where the location distance spans multiple lines? Such as a call with arguments on each line?

I'm not sure if we're currently verifying that locations monotonically increase (@dcci ?), but you may want to check that the current location is greater than the previous location before printing anything.

[meg-gupta]

I updated with the > check to compare source locations. And with that a call like:

@inline(never)
func foo() { 
  bar(1, 
  2,
  3)
}

would look like:

// foo()
sil hidden [noinline] @$s9printtest3fooyyF : $@convention(thin) () -> () { 
bb0:
  //   bar(1,
  %0 = integer_literal $Builtin.Int64, 1          // user: %1
  %1 = struct $Int (%0 : $Builtin.Int64)          // user: %7
  //   2,
  %2 = integer_literal $Builtin.Int64, 2          // user: %3
  %3 = struct $Int (%2 : $Builtin.Int64)          // user: %7
  //   3)
  %4 = integer_literal $Builtin.Int64, 3          // user: %5
  %5 = struct $Int (%4 : $Builtin.Int64)          // user: %7
  // function_ref bar(_:_:_:)
  %6 = function_ref @$s9printtest3baryySi_S2itF : $@convention(thin) (Int, Int, Int) -> () // user: %7
  %7 = apply %6(%1, %3, %5) : $@convention(thin) (Int, Int, Int) -> ()
  // } 
  %8 = tuple ()                                   // user: %9
  return %8 : $()                                 // id: %9
} // end sil function '$s9printtest3fooyyF'

[meg-gupta]

I don't see a way where I could print all of the call arguments at once looking at the API's available on SourceLoc.

[atrick]

Why can't you print all source lines between prevLoc and currLoc? What happens with

func foo(a, b, c) {
  bar(
   a,
   b,
   c)
}

[meg-gupta]

Yeah, for this it prints only the first line:

bb0(%0 : $Int, %1 : $Int, %2 : $Int):
  // func foo(_ a:Int, _ b:Int, _ c:Int) {
  debug_value %0 : $Int, let, name "a", argno 1   // id: %3
  debug_value %1 : $Int, let, name "b", argno 2   // id: %4
  debug_value %2 : $Int, let, name "c", argno 3   // id: %5
  //   bar(a,
  // function_ref bar(_:_:_:)
  %6 = function_ref @$s9printtest3baryySi_S2itF : $@convention(thin) (Int, Int, Int) -> () // user: %7
  %7 = apply %6(%0, %1, %2) : $@convention(thin) (Int, Int, Int) -> () 
  // }  
  %8 = tuple ()                                   // user: %9
  return %8 : $()                                 // id: %9
} // end sil function '$s9printtest3fooyySi_S2itF'

I was worried about hoisting and some other optimizations that can print out too many source lines if I try to print between prevLoc and currLoc.
I think the same issue can happen with checking curLoc > prevLoc now.

[atrick]

I misunderstood your intention. If it's more useful to see the source at a fine granularity as the SIL jumps around, then you should go back to the PrevLoc != CurLoc test, but in that case I think you really need to print line numbers to make sense of it.

[meg-gupta]

Right, I added the line numbers as well now.

[dcci]

@atrick We currently don't have that verification enabled.

[atrick]

@dcci Anyway, the verification is for -Onone and it seems that the main use case for this is understanding -O output.

[dcci]

Yes, I agree.

[meg-gupta]

@swift-ci please smoke test

[meg-gupta]

@swift-ci please smoke test