[flang] [flang-rt] Subscript overrun occurs in namelists during a READ command.

[kwyatt-ext]

The following test was designed to test proper error reporting when reading with an invalid namelist record. Using flang, this test hangs or produces a seg fault. This safely errors out using cray ftn and gfortran.

Test:

! Test a buffer overrun when an illegal vector-valued subscript is used in
! namelist input.
! The error should be reported through the READ's IOSTAT value.

PROGRAM bad_subscript_overrun01
  IMPLICIT NONE

  INTEGER,DIMENSION(5)                :: U, EXPECTU
  INTEGER,DIMENSION(5)                :: V, EXPECTV
  CHARACTER(LEN=20)                   :: NAMELIST_RECORD
  INTEGER                             :: IOS, ILOOP

  NAMELIST /SCORES/ U
  NAMELIST /CHTEST/ NAMELIST_RECORD

  U = 8
  EXPECTU = U
  V = 9
  EXPECTV = V
  IOS = 0

  NAMELIST_RECORD = " &SCORES U(V) = -1 /"
  OPEN(UNIT=10, ACCESS='SEQUENTIAL', ACTION='READWRITE')
  WRITE(10,'(A)') NAMELIST_RECORD
  REWIND 10

  ! This should fail because of the bad index.
  READ(10, NML = SCORES, IOSTAT=IOS)
  CLOSE(UNIT=10, STATUS='KEEP')

  ! Make sure the READ status was a failure.
  IF(IOS.NE.0) THEN
    PRINT *, "Test 1 - PASS"
  ELSE
    print *, "Test 1 - FAIL"
  ENDIF

  ! Make sure the values of the array haven't changed.
  DO ILOOP = 1,5
    IF(U(ILOOP).EQ.EXPECTU(ILOOP)) THEN
      PRINT *, "Test 2 - PASS"
    ELSE
      PRINT *, "Test 2 - FAIL"
    ENDIF
  ENDDO

END PROGRAM bad_subscript_overrun01

flang:

wyattke@pe34genoa:~/builds/flang_work/llvm-project/test> ../../cpe-13666/build/bin/flang-new bad_subscript_overrun01.f90

wyattke@pe34genoa:~/builds/flang_work/llvm-project/test> time ./a.out
^C

real    2m36.279s
user    2m36.185s
sys     0m0.005s

gfortran:

wyattke@pe34genoa:~/builds/flang_work/llvm-project/test> gfortran bad_subscript_overrun01.f90
wyattke@pe34genoa:~/builds/flang_work/llvm-project/test> ./a.out
 Test 1 - PASS
 Test 2 - PASS
 Test 2 - PASS
 Test 2 - PASS
 Test 2 - PASS
 Test 2 - PASS

cray ftn:

wyattke@pe34genoa:~/builds/flang_work/llvm-project/test> ftn bad_subscript_overrun01.f90
wyattke@pe34genoa:~/builds/flang_work/llvm-project/test> ./a.out
 Test 1 - PASS
 Test 2 - PASS
 Test 2 - PASS
 Test 2 - PASS
 Test 2 - PASS
 Test 2 - PASS

[kwyatt-ext]

Could someone please assign this to me? I don't have write permissions.

[kwyatt-ext]

Link to the associated PRs:
#176959

llvm/llvm-test-suite#361