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
We had neglected to check for name mismatches for procedure definitions that
appear in interfaces.
I also changed label11.f90 to an error test since I think they're better than
"FileCheck" tests.
Differential Revision: https://reviews.llvm.org/D89611
Compilation of the following program currently generates a warning message:
i = 1
if (i .eq. 0) then
write(6, 200) i
200 format (I8)
end if
write(6, 200) i
end
x.f90:6:9: Label '200' is not in scope
write(6, 200) i
^^^^^^^^^^^^^^^
Whereas branch targets must conform to the Clause 11.1.2.1 program
requirement "Transfer of control to the interior of a block from
outside the block is prohibited, ...", this doesn't apply to format
statement references.
peter klausler