llvm-project/flang/test/Semantics/label16.f90

! RUN: %S/test_errors.sh %s %t %f18

subroutine x(n)
   call x1(n)
   if (n == 0) goto 88
   print*, 'x'
contains
   subroutine x1(n)
      if (n == 0) goto 77 ! ok
      print*, 'x1'
      !ERROR: Label '88' was not found
      goto 88
77 end subroutine x1
88 end
[flang] Allow labels on END statements. F18 clause 5.3.3 explicitly allows labels on program unit END statements. Label resolution code accounts for this for singleton program units, but incorrectly generates an error for host subprograms with internal subprograms. subroutine s(n) call s1(n) if (n == 0) goto 88 ! incorrect error print, 's' contains subroutine s1(n) if (n == 0) goto 77 ! ok print, 's1' 77 end subroutine s1 88 end Label resolution code makes a sequential pass over an entire file to collect label information for all subprograms, followed by a pass through that information for semantics checks. The problem is that END statements may be separated from prior subprogram code by internal subprogram definitions, so an END label can be associated with the wrong subprogram. There are several ways to fix this. Labels are always local to a subprogram. So the two separate passes over the entire file could probably instead be interleaved to perform analysis on a subprogram as soon as the end of the subprogram is reached, using a small stack. The stack structure would account for the "split" code case. This might work. It is possible that there is some not otherwise apparent advantage to the current full-file pass design. The parse tree has productions that provide access to a subprogram END statement "in advance". An alternative is to access this information to solve the problem. This PR implements this latter option. Differential revision: https://reviews.llvm.org/D91217 2020-11-11 07:03:21 +08:00			`! RUN: %S/test_errors.sh %s %t %f18`

			`subroutine x(n)`
			`call x1(n)`
			`if (n == 0) goto 88`
			`print*, 'x'`
			`contains`
			`subroutine x1(n)`
			`if (n == 0) goto 77 ! ok`
			`print*, 'x1'`
			`!ERROR: Label '88' was not found`
			`goto 88`
			`77 end subroutine x1`
			`88 end`