re PR fortran/90903 (Implement runtime checks for bit manipulation intrinsics)

2019-07-16  Harald Anlauf  <anlauf@gmx.de>

	PR fortran/90903
	* libgfortran.h: Add mask for -fcheck=bits option.
	* options.c (gfc_handle_runtime_check_option): Add option "bits"
	to run-time checks selectable via -fcheck.
	* trans-intrinsic.c (gfc_conv_intrinsic_btest)
	(gfc_conv_intrinsic_singlebitop, gfc_conv_intrinsic_ibits)
	(gfc_conv_intrinsic_shift, gfc_conv_intrinsic_ishft)
	(gfc_conv_intrinsic_ishftc): Implement run-time checks for the
	POS, LEN, SHIFT, and SIZE arguments.
	* gfortran.texi: Document run-time checks for bit manipulation
	intrinsics.
	* invoke.texi: Document new -fcheck=bits option.

	PR fortran/90903
	* gfortran.dg/check_bits_1.f90: New testcase.

From-SVN: r273535

gcc/fortran/ChangeLog

+2019-07-16  Harald Anlauf  <anlauf@gmx.de>
+
+	PR fortran/90903
+	* libgfortran.h: Add mask for -fcheck=bits option.
+	* options.c (gfc_handle_runtime_check_option): Add option "bits"
+	to run-time checks selectable via -fcheck.
+	* trans-intrinsic.c (gfc_conv_intrinsic_btest)
+	(gfc_conv_intrinsic_singlebitop, gfc_conv_intrinsic_ibits)
+	(gfc_conv_intrinsic_shift, gfc_conv_intrinsic_ishft)
+	(gfc_conv_intrinsic_ishftc): Implement run-time checks for the
+	POS, LEN, SHIFT, and SIZE arguments.
+	* gfortran.texi: Document run-time checks for bit manipulation
+	intrinsics.
+	* invoke.texi: Document new -fcheck=bits option.
+
 2019-07-14  Jerry DeLisle  <jvdelisle@gcc.gnu.org>
 
 	PR fortran/87233

gcc/fortran/gfortran.texi

@@ -3790,7 +3790,8 @@ initialization using @code{_gfortran_set_args}.
 Default: enabled.
 @item @var{option}[6] @tab Enables run-time checking.  Possible values
 are (bitwise or-ed): GFC_RTCHECK_BOUNDS (1), GFC_RTCHECK_ARRAY_TEMPS (2),
-GFC_RTCHECK_RECURSION (4), GFC_RTCHECK_DO (16), GFC_RTCHECK_POINTER (32).
+GFC_RTCHECK_RECURSION (4), GFC_RTCHECK_DO (16), GFC_RTCHECK_POINTER (32),
+GFC_RTCHECK_BITS (64).
 Default: disabled.
 @item @var{option}[7] @tab Unused.
 @item @var{option}[8] @tab Show a warning when invoking @code{STOP} and

gcc/fortran/invoke.texi

@@ -183,7 +183,7 @@ and warnings}.
 @gccoptlist{-faggressive-function-elimination -fblas-matmul-limit=@var{n} @gol
 -fbounds-check -ftail-call-workaround -ftail-call-workaround=@var{n} @gol
 -fcheck-array-temporaries @gol
--fcheck=@var{<all|array-temps|bounds|do|mem|pointer|recursion>} @gol
+-fcheck=@var{<all|array-temps|bits|bounds|do|mem|pointer|recursion>} @gol
 -fcoarray=@var{<none|single|lib>} -fexternal-blas -ff2c
 -ffrontend-loop-interchange @gol
 -ffrontend-optimize @gol
@@ -1558,6 +1558,7 @@ library needs to be linked.
 @item -fcheck=@var{<keyword>}
 @opindex @code{fcheck}
 @cindex array, bounds checking
+@cindex bit intrinsics checking
 @cindex bounds checking
 @cindex pointer checking
 @cindex memory checking
@@ -1582,6 +1583,10 @@ sometimes useful in optimization, in order to avoid such temporaries.
 
 Note: The warning is only printed once per location.
 
+@item @samp{bits}
+Enable generation of run-time checks for invalid arguments to the bit
+manipulation intrinsics.
+
 @item @samp{bounds}
 Enable generation of run-time checks for array subscripts
 and against the declared minimum and maximum values.  It also

gcc/fortran/libgfortran.h

@@ -73,9 +73,11 @@ along with GCC; see the file COPYING3.  If not see
 #define GFC_RTCHECK_DO          (1<<3)
 #define GFC_RTCHECK_POINTER     (1<<4)
 #define GFC_RTCHECK_MEM         (1<<5)
+#define GFC_RTCHECK_BITS        (1<<6)
 #define GFC_RTCHECK_ALL        (GFC_RTCHECK_BOUNDS | GFC_RTCHECK_ARRAY_TEMPS \
 				| GFC_RTCHECK_RECURSION | GFC_RTCHECK_DO \
-				| GFC_RTCHECK_POINTER | GFC_RTCHECK_MEM)
+				| GFC_RTCHECK_POINTER | GFC_RTCHECK_MEM \
+				| GFC_RTCHECK_BITS)
 
 /* Special unit numbers used to convey certain conditions.  Numbers -4
    thru -9 available.  NEWUNIT values start at -10.  */

gcc/fortran/options.c

@@ -580,12 +580,12 @@ gfc_handle_runtime_check_option (const char *arg)
   int result, pos = 0, n;
   static const char * const optname[] = { "all", "bounds", "array-temps",
 					  "recursion", "do", "pointer",
-					  "mem", NULL };
+					  "mem", "bits", NULL };
   static const int optmask[] = { GFC_RTCHECK_ALL, GFC_RTCHECK_BOUNDS,
 				 GFC_RTCHECK_ARRAY_TEMPS,
 				 GFC_RTCHECK_RECURSION, GFC_RTCHECK_DO,
 				 GFC_RTCHECK_POINTER, GFC_RTCHECK_MEM,
-				 0 };
+				 GFC_RTCHECK_BITS, 0 };
  
   while (*arg)
     {

gcc/testsuite/ChangeLog

+2019-07-16  Harald Anlauf  <anlauf@gmx.de>
+
+	PR fortran/90903
+	* gfortran.dg/check_bits_1.f90: New testcase.
+
 2019-07-16  Jeff Law  <law@redhat.com>
 
 	PR rtl-optimization/91173

gcc/testsuite/gfortran.dg/check_bits_1.f90

+! { dg-do run }
+! { dg-options "-fcheck=bits -fdump-tree-original" }
+! { dg-shouldfail "Fortran runtime error: SIZE argument (0) out of range 1:32 in intrinsic ISHFTC" }
+! { dg-output "At line 44 .*" }
+!
+! Verify that the runtime checks for the bit manipulation intrinsic functions
+! do not generate false-positives
+program check
+  implicit none
+  integer :: i, k, pos, len, shift, size, nb
+  nb = bit_size (i)
+  i = 0
+  do pos = 0, nb-1
+     k = ibset (i, pos)
+     i = ibclr (k, pos)
+     if (btest (i, pos)) stop 1
+  end do
+  do pos = 0, nb
+     do len = 0, nb-pos
+        i = ibits (i, pos, len)
+     end do
+  end do
+  do shift = 0, nb
+     k = ishft (i,  shift)
+     i = ishft (k, -shift)
+  end do
+  do shift = 0, nb
+     k = shiftl (i, shift) ! Fortran 2008
+     i = shiftr (k, shift)
+     i = shifta (i, shift)
+     k = lshift (i, shift) ! GNU extensions
+     i = rshift (k, shift)
+  end do
+  do shift = 0, nb
+     k = ishftc (i,  shift)
+     i = ishftc (k, -shift)
+     do size = max (1,shift), nb
+        k = ishftc (i,  shift, size)
+        i = ishftc (k, -shift, size)
+     end do
+  end do
+  size = 0
+  ! The following line should fail with a runtime error:
+  k = ishftc (i, 0, size)
+  ! Should never get here with -fcheck=bits
+  stop 2
+end program check
+
+! { dg-final { scan-tree-dump-times "_gfortran_runtime_error_at" 21 "original" } }