Re: [Patch, fortran] PR fortran/92142 - CFI_setpointer corrupts descriptor

[José Rui Faustino de Sousa <jrfsousa at gmail dot com>]

Hi,

On 17/10/19 17:29, Tobias Burnus wrote:
> If you generate to stdout/stderr like in this case, I think it makes 
> sense to also check for this output using "{dg-output …}".

Added the suggested check and a few touches to comments and the error 
message.

> that might be a bug in the C 
> code of the test itself 

I took a look and although there are problems with the code of the test 
I do not think they are relevant.

Index: gcc/testsuite/gfortran.dg/ISO_Fortran_binding_10.c
===================================================================
--- gcc/testsuite/gfortran.dg/ISO_Fortran_binding_10.c	(revision 277537)
+++ gcc/testsuite/gfortran.dg/ISO_Fortran_binding_10.c	(working copy)
@@ -15,7 +15,7 @@
   bool err;
   CFI_CDESC_T(1) that;
   CFI_index_t lb[] = { 0, 0 };
-  CFI_index_t ub[] = { 4, 1 };
+  CFI_index_t ub[] = { 4, 0 };
   CFI_index_t st[] = { 2, 0 };
   int chksum[] = { 9, 36, 38 };

@@ -39,7 +39,7 @@

   if (*status != CFI_SUCCESS)
     {
-      printf("FAIL C: status is %i\n",status);
+      printf("FAIL C: status is %i\n", *status);
       return;
     }

Best regards,
José Rui

Index: libgfortran/runtime/ISO_Fortran_binding.c
===================================================================
--- libgfortran/runtime/ISO_Fortran_binding.c	(revision 277537)
+++ libgfortran/runtime/ISO_Fortran_binding.c	(working copy)
@@ -794,13 +794,23 @@
 int CFI_setpointer (CFI_cdesc_t *result, CFI_cdesc_t *source,
 		    const CFI_index_t lower_bounds[])
 {
-  /* Result must not be NULL. */
-  if (unlikely (compile_options.bounds_check) && result == NULL)
+  /* Result must not be NULL and must be a Fortran pointer. */
+  if (unlikely (compile_options.bounds_check))
     {
-      fprintf (stderr, "CFI_setpointer: Result is NULL.\n");
-      return CFI_INVALID_DESCRIPTOR;
+      if (result == NULL)
+	{
+	  fprintf (stderr, "CFI_setpointer: Result is NULL.\n");
+	  return CFI_INVALID_DESCRIPTOR;
+	}
+      
+      if (result->attribute != CFI_attribute_pointer)
+	{
+ 	  fprintf (stderr, "CFI_setpointer: Result shall be the address of a "
+		   "C descriptor for a Fortran pointer.\n");
+ 	  return CFI_INVALID_ATTRIBUTE;
+ 	}
     }
-
+      
   /* If source is NULL, the result is a C Descriptor that describes a
    * disassociated pointer. */
   if (source == NULL)
@@ -807,7 +817,6 @@
     {
       result->base_addr = NULL;
       result->version  = CFI_VERSION;
-      result->attribute = CFI_attribute_pointer;
     }
   else
     {
@@ -851,7 +860,6 @@
 
       /* Assign components to result. */
       result->version = source->version;
-      result->attribute = source->attribute;
 
       /* Dimension information. */
       for (int i = 0; i < source->rank; i++)
Index: gcc/testsuite/gfortran.dg/ISO_Fortran_binding_15.c
===================================================================
--- gcc/testsuite/gfortran.dg/ISO_Fortran_binding_15.c	(nonexistent)
+++ gcc/testsuite/gfortran.dg/ISO_Fortran_binding_15.c	(working copy)
@@ -0,0 +1,40 @@
+/* Test the fix for PR92142. */
+
+#include "../../../libgfortran/ISO_Fortran_binding.h"
+
+#include <stdlib.h>
+
+int c_setpointer(CFI_cdesc_t *);
+
+int c_setpointer(CFI_cdesc_t *ip)
+{
+  CFI_cdesc_t *yp = NULL;
+  void *auxp = ip->base_addr;
+  int ierr;
+  int status;
+
+  /* Setting up the pointer */
+  ierr = 1;
+  yp = malloc(sizeof(*ip));
+  if (yp == NULL) return ierr;
+  status = CFI_establish(yp, NULL, CFI_attribute_pointer, ip->type, ip->elem_len, ip->rank, NULL);
+  if (status != CFI_SUCCESS) return ierr;
+  if (yp->attribute != CFI_attribute_pointer) return ierr;
+  /* Set the pointer to ip */
+  ierr = 2;
+  status = CFI_setpointer(yp, ip, NULL);
+  if (status != CFI_SUCCESS) return ierr;
+  if (yp->attribute != CFI_attribute_pointer) return ierr;
+  /* Set the pointer to NULL */
+  ierr = 3;
+  status = CFI_setpointer(yp, NULL, NULL);
+  if (status != CFI_SUCCESS) return ierr;
+  if (yp->attribute != CFI_attribute_pointer) return ierr;
+  /* "Set" the ip variable to yp (should not be possible) */
+  ierr = 4;
+  status = CFI_setpointer(ip, yp, NULL);
+  if (status != CFI_INVALID_ATTRIBUTE) return ierr;
+  if (ip->attribute != CFI_attribute_other) return ierr;
+  if (ip->base_addr != auxp) return ierr;
+  return 0;
+}
Index: gcc/testsuite/gfortran.dg/ISO_Fortran_binding_15.f90
===================================================================
--- gcc/testsuite/gfortran.dg/ISO_Fortran_binding_15.f90	(nonexistent)
+++ gcc/testsuite/gfortran.dg/ISO_Fortran_binding_15.f90	(working copy)
@@ -0,0 +1,25 @@
+! { dg-do run }
+! { dg-additional-options "-fbounds-check" }
+! { dg-additional-sources ISO_Fortran_binding_15.c }
+!
+! Test the fix for PR92142.
+!
+  use, intrinsic :: iso_c_binding, only: c_int
+
+  implicit none
+  
+  interface
+    function c_setpointer(ip) result(ierr) bind(c)
+      use, intrinsic :: iso_c_binding, only: c_int
+      type(*), dimension(..), target :: ip
+      integer(c_int)                 :: ierr
+    end function c_setpointer
+  end interface
+  
+  integer(c_int) :: it = 1
+  
+  if (c_setpointer(it) /= 0) stop 1
+  
+end
+
+! { dg-output "CFI_setpointer: Result shall be the address of a C descriptor for a Fortran pointer." }