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Re: [patches,fortran] Add POINTER INTENT(*) support (PR29624)


* PING *

Tobias

PS: Somewhat late I wish Merry Christmas and - still in time - a happy
New Year to all!


Tobias Burnus wrote:
>> The standard can be found at
>> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29624#c0
>>
>> In a nutshell: With intent(in) the pointer dummy argument's association
>> shall not be changed, the target may.
>>
>> Thanks to Tobias S. for pointing out that I was looking at the wrong
>> thing in terms of attributes.
>>
>> Quick remark to compound structures:
>> - If the last subobject is a pointer & its association is changed, I
>> check whether somewhere higher up in the hierarchy is already a pointer,
>> because then the subobject is a target of that one. => Modification allowed.
>> - If the last subobject is a pointer & its value target value is changed
>> => Modification always allowed
>> - If the last subobject is a nonpointer: Check whether somewhere higher
>> up in the hierarchy is already a pointer, because then the subobject is
>> a target of that one. => Modification allowed.
>
> modified patch; the change in resolve_deallocate_exp caused the following regression:
>
>   deallocate(pointerToArray(0))
>
> was accepted, which provoked later an ICE. With the following change
> (interdiff) this it detected. I added also a check to the test suite to
> make sure this does not happen again.
>
> Regression tested on x86_64-unknown-linux-gnu.
>
> Tobias
>   
fortran/
2006-12-12  Tobias Burnus  <burnus@net-b.de>

	PR fortran/29624
	* interface.c (compare_parameter_intent): New function.
	  (check_intents): Support pointer intents.
	* symbol.c (check_conflict): Support pointer intents,
	  better conflict_std message.
	* expr.c (gfc_check_assign,gfc_check_pointer_assign):
	  Support pointer intents.
	* resolve.c (resolve_deallocate_expr,resolve_allocate_expr):
	  Support pointer intents.

testsuite/
2006-12-12  Tobias Burnus  <burnus@net-b.de>

	PR fortran/29624
	* gfortran.dg/alloc_alloc_expr_1.f90: Add check for
	  invalid deallocate.
	* gfortran.dg/allocatable_dummy_2.f90: Update dg-error.
	* gfortran.dg/protected_4.f90: Add pointer intent check.
	* gfortran.dg/protected_6.f90: Add pointer intent check.
	* gfortran.dg/pointer_intent_1.f90: New test.
	* gfortran.dg/pointer_intent_2.f90: New test.
	* gfortran.dg/pointer_intent_3.f90: New test.

Index: gcc/fortran/interface.c
===================================================================
--- gcc/fortran/interface.c	(Revision 119993)
+++ gcc/fortran/interface.c	(Arbeitskopie)
@@ -1648,6 +1648,28 @@
 }
 
 
+/* Given a symbol of a formal argument list and an expression, see if
+   their intents are compatible.  Returns nonzero if compatible,
+   zero if not compatible.  */
+
+static int
+compare_parameter_intent (gfc_symbol * formal, gfc_expr * actual)
+{
+  if (actual->symtree->n.sym->attr.pointer
+      && !formal->attr.pointer)
+    return 1;
+
+  if (actual->symtree->n.sym->attr.intent != INTENT_IN)
+    return 1;
+
+  if (formal->attr.intent == INTENT_INOUT
+      || formal->attr.intent == INTENT_OUT)
+    return 0;
+
+  return 1;
+}
+
+
 /* Given formal and actual argument lists that correspond to one
    another, check that they are compatible in the sense that intents
    are not mismatched.  */
@@ -1655,7 +1677,7 @@
 static try
 check_intents (gfc_formal_arglist * f, gfc_actual_arglist * a)
 {
-  sym_intent a_intent, f_intent;
+  sym_intent f_intent;
 
   for (;; f = f->next, a = a->next)
     {
@@ -1667,12 +1689,9 @@
       if (a->expr == NULL || a->expr->expr_type != EXPR_VARIABLE)
 	continue;
 
-      a_intent = a->expr->symtree->n.sym->attr.intent;
       f_intent = f->sym->attr.intent;
 
-      if (a_intent == INTENT_IN
-	  && (f_intent == INTENT_INOUT
-	      || f_intent == INTENT_OUT))
+      if (!compare_parameter_intent(f->sym, a->expr))
 	{
 
 	  gfc_error ("Procedure argument at %L is INTENT(IN) while interface "
Index: gcc/fortran/symbol.c
===================================================================
--- gcc/fortran/symbol.c	(Revision 119993)
+++ gcc/fortran/symbol.c	(Arbeitskopie)
@@ -288,7 +288,8 @@
     {
       a1 = pointer;
       a2 = intent;
-      goto conflict;
+      standard = GFC_STD_F2003;
+      goto conflict_std;
     }
 
   /* Check for attributes not allowed in a BLOCK DATA.  */
@@ -571,14 +572,18 @@
 conflict_std:
   if (name == NULL)
     {
-      return gfc_notify_std (standard, "In the selected standard, %s attribute "
-                             "conflicts with %s attribute at %L", a1, a2,
-                             where);
+      return gfc_notify_std (standard, "%s: %s attribute with %s attribute "
+                             "at %L",
+                             (standard == GFC_STD_F2003)
+                               ? "Fortran 2003" : "Not in the selected standard",
+                             a1, a2, where);
     }
   else
     {
-      return gfc_notify_std (standard, "In the selected standard, %s attribute "
-                             "conflicts with %s attribute in '%s' at %L",
+      return gfc_notify_std (standard, "%s: %s attribute with %s attribute "
+                             "in '%s' at %L",
+                             (standard == GFC_STD_F2003)
+                               ? "Fortran 2003" : "Not in the selected standard",
                              a1, a2, name, where);
     }
 }
Index: gcc/fortran/expr.c
===================================================================
--- gcc/fortran/expr.c	(Revision 119993)
+++ gcc/fortran/expr.c	(Arbeitskopie)
@@ -2188,12 +2188,25 @@
 gfc_check_assign (gfc_expr * lvalue, gfc_expr * rvalue, int conform)
 {
   gfc_symbol *sym;
+  gfc_ref *ref;
+  int has_pointer;
 
   sym = lvalue->symtree->n.sym;
 
-  if (sym->attr.intent == INTENT_IN)
+  /* Check INTENT(IN), unless the object itself of higher up in the
+     hierarchy is a pointer.  */
+  has_pointer = sym->attr.pointer;
+
+  for (ref = lvalue->ref; ref; ref = ref->next)
+    if (ref->type == REF_COMPONENT && ref->u.c.component->pointer)
+      {
+	has_pointer = 1;
+	break;
+      }
+
+  if (!has_pointer && sym->attr.intent == INTENT_IN)
     {
-      gfc_error ("Can't assign to INTENT(IN) variable '%s' at %L",
+      gfc_error ("Cannot assign to INTENT(IN) variable '%s' at %L",
 		 sym->name, &lvalue->where);
       return FAILURE;
     }
@@ -2318,7 +2331,9 @@
 gfc_check_pointer_assign (gfc_expr * lvalue, gfc_expr * rvalue)
 {
   symbol_attribute attr;
+  gfc_ref *ref;
   int is_pure;
+  int pointer, check_intent_in;
 
   if (lvalue->symtree->n.sym->ts.type == BT_UNKNOWN)
     {
@@ -2336,8 +2351,29 @@
       return FAILURE;
     }
 
-  attr = gfc_variable_attr (lvalue, NULL);
-  if (!attr.pointer)
+
+  /* Check INTENT(IN), unless the object itself of higher up in the
+     hierarchy is a pointer.  */
+  check_intent_in = 1;
+  pointer = lvalue->symtree->n.sym->attr.pointer;
+
+  for (ref = lvalue->ref; ref; ref = ref->next)
+    {
+      if (pointer)
+        check_intent_in = 0;
+
+      if (ref->type == REF_COMPONENT && ref->u.c.component->pointer)
+        pointer = 1;
+    }
+
+  if (check_intent_in && lvalue->symtree->n.sym->attr.intent == INTENT_IN)
+    {
+      gfc_error ("Cannot assign to INTENT(IN) variable '%s' at %L",
+                 lvalue->symtree->n.sym->name, &lvalue->where);
+      return FAILURE;
+    }
+
+  if (!pointer)
     {
       gfc_error ("Pointer assignment to non-POINTER at %L", &lvalue->where);
       return FAILURE;
Index: gcc/fortran/resolve.c
===================================================================
--- gcc/fortran/resolve.c	(Revision 119993)
+++ gcc/fortran/resolve.c	(Arbeitskopie)
@@ -3318,48 +3318,58 @@
 resolve_deallocate_expr (gfc_expr * e)
 {
   symbol_attribute attr;
-  int allocatable;
+  int allocatable, pointer, check_intent_in;
   gfc_ref *ref;
 
+  /* Check INTENT(IN), unless an object higher up in the
+     hierarchy is a pointer.  */
+  check_intent_in = 1;
+
   if (gfc_resolve_expr (e) == FAILURE)
     return FAILURE;
 
-  attr = gfc_expr_attr (e);
-  if (attr.pointer)
-    return SUCCESS;
-
   if (e->expr_type != EXPR_VARIABLE)
     goto bad;
 
   allocatable = e->symtree->n.sym->attr.allocatable;
+  pointer = e->symtree->n.sym->attr.pointer;
   for (ref = e->ref; ref; ref = ref->next)
-    switch (ref->type)
-      {
-      case REF_ARRAY:
-	if (ref->u.ar.type != AR_FULL)
-	  allocatable = 0;
-	break;
+    {
+      if (pointer)
+        check_intent_in = 0;
 
-      case REF_COMPONENT:
-	allocatable = (ref->u.c.component->as != NULL
-		       && ref->u.c.component->as->type == AS_DEFERRED);
-	break;
+      switch (ref->type)
+        {
+        case REF_ARRAY:
+	  if (ref->u.ar.type != AR_FULL)
+	    allocatable = 0;
+	  break;
 
-      case REF_SUBSTRING:
-	allocatable = 0;
-	break;
-      }
+        case REF_COMPONENT:
+	  allocatable = (ref->u.c.component->as != NULL
+		         && ref->u.c.component->as->type == AS_DEFERRED);
+	  pointer = ref->u.c.component->pointer;
+	  break;
+
+        case REF_SUBSTRING:
+	  allocatable = 0;
+	  break;
+        }
+    }
 
-  if (allocatable == 0)
+  attr = gfc_expr_attr (e);
+
+  if (allocatable == 0 && attr.pointer == 0)
     {
     bad:
       gfc_error ("Expression in DEALLOCATE statement at %L must be "
 		 "ALLOCATABLE or a POINTER", &e->where);
     }
 
-  if (e->symtree->n.sym->attr.intent == INTENT_IN)
+  if (check_intent_in
+      && e->symtree->n.sym->attr.intent == INTENT_IN)
     {
-      gfc_error ("Can't deallocate INTENT(IN) variable '%s' at %L",
+      gfc_error ("Cannot deallocate INTENT(IN) variable '%s' at %L",
                  e->symtree->n.sym->name, &e->where);
       return FAILURE;
     }
@@ -3481,7 +3491,7 @@
 static try
 resolve_allocate_expr (gfc_expr * e, gfc_code * code)
 {
-  int i, pointer, allocatable, dimension;
+  int i, pointer, allocatable, dimension, check_intent_in;
   symbol_attribute attr;
   gfc_ref *ref, *ref2;
   gfc_array_ref *ar;
@@ -3490,6 +3500,10 @@
   gfc_symbol *sym;
   gfc_alloc *a;
 
+  /* Check INTENT(IN), unless an object higher up in the
+     hierarchy is a pointer.  */
+  check_intent_in = 1;
+
   if (gfc_resolve_expr (e) == FAILURE)
     return FAILURE;
 
@@ -3527,26 +3541,31 @@
 	}
 
       for (ref = e->ref; ref; ref2 = ref, ref = ref->next)
-	switch (ref->type)
-	  {
-	  case REF_ARRAY:
-	    if (ref->next != NULL)
-	      pointer = 0;
-	    break;
-
-	  case REF_COMPONENT:
-	    allocatable = (ref->u.c.component->as != NULL
-			   && ref->u.c.component->as->type == AS_DEFERRED);
-
-	    pointer = ref->u.c.component->pointer;
-	    dimension = ref->u.c.component->dimension;
-	    break;
+        {
+	  if (pointer)
+	    check_intent_in = 0;
 
-	  case REF_SUBSTRING:
-	    allocatable = 0;
-	    pointer = 0;
-	    break;
-	  }
+	  switch (ref->type)
+	    {
+ 	      case REF_ARRAY:
+	        if (ref->next != NULL)
+	          pointer = 0;
+	        break;
+
+	      case REF_COMPONENT:
+	        allocatable = (ref->u.c.component->as != NULL
+			      && ref->u.c.component->as->type == AS_DEFERRED);
+
+	        pointer = ref->u.c.component->pointer;
+	        dimension = ref->u.c.component->dimension;
+	        break;
+
+	      case REF_SUBSTRING:
+	        allocatable = 0;
+	        pointer = 0;
+	        break;
+	    }
+       }
     }
 
   if (allocatable == 0 && pointer == 0)
@@ -3556,9 +3575,10 @@
       return FAILURE;
     }
 
-  if (e->symtree->n.sym->attr.intent == INTENT_IN)
+  if (check_intent_in
+      && e->symtree->n.sym->attr.intent == INTENT_IN)
     {
-      gfc_error ("Can't allocate INTENT(IN) variable '%s' at %L",
+      gfc_error ("Cannot allocate INTENT(IN) variable '%s' at %L",
                  e->symtree->n.sym->name, &e->where);
       return FAILURE;
     }
Index: gcc/testsuite/gfortran.dg/protected_4.f90
===================================================================
--- gcc/testsuite/gfortran.dg/protected_4.f90	(Revision 119989)
+++ gcc/testsuite/gfortran.dg/protected_4.f90	(Arbeitskopie)
@@ -21,6 +21,7 @@
   use protmod
   implicit none
   integer   :: j 
+  logical   :: asgnd
   protected :: j ! { dg-error "only allowed in specification part of a module" }
   a = 43       ! { dg-error "Assigning to PROTECTED variable" }
   ap => null() ! { dg-error "Assigning to PROTECTED variable" }
@@ -30,6 +31,8 @@
   allocate(ap) ! { dg-error "Assigning to PROTECTED variable" }
   ap = 73      ! { dg-error "Assigning to PROTECTED variable" }
   call increment(a,at) ! { dg-error "use-associated with PROTECTED attribute" }
+  call pointer_assignments(ap) ! { dg-error "is use-associated with PROTECTED attribute" }
+  asgnd = pointer_check(ap)
 contains
   subroutine increment(a1,a3)
     integer, intent(inout) :: a1, a3
@@ -37,9 +40,14 @@
     a3 = a3 + 1
   end subroutine increment
   subroutine pointer_assignments(p)
-    integer, pointer :: p ! with [pointer] intent(out)
-    p => null()           ! this is invalid
+    integer, pointer,intent(out) :: p
+    p => null()           
   end subroutine pointer_assignments
+  function pointer_check(p)
+    integer, pointer,intent(in) :: p
+    logical :: pointer_check
+    pointer_check = associated(p)
+  end function pointer_check
 end program main
 
 module test
Index: gcc/testsuite/gfortran.dg/protected_6.f90
===================================================================
--- gcc/testsuite/gfortran.dg/protected_6.f90	(Revision 119989)
+++ gcc/testsuite/gfortran.dg/protected_6.f90	(Arbeitskopie)
@@ -27,6 +27,7 @@
   allocate(ap) ! { dg-error "Assigning to PROTECTED variable" }
   ap = 73      ! { dg-error "Assigning to PROTECTED variable" }
   call increment(a,at) ! { dg-error "use-associated with PROTECTED attribute" }
+  call pointer_assignments(ap) ! { dg-error "is use-associated with PROTECTED attribute" }
 contains
   subroutine increment(a1,a3)
     integer, intent(inout) :: a1, a3
@@ -34,8 +35,8 @@
     a3 = a3 + 1
   end subroutine increment
   subroutine pointer_assignments(p)
-    integer, pointer :: p ! with [pointer] intent(out)
-    p => null()           ! this is invalid
+    integer, pointer,intent (inout) :: p
+    p => null()
   end subroutine pointer_assignments
 end program main
 
Index: gcc/testsuite/gfortran.dg/alloc_alloc_expr_1.f90
===================================================================
--- gcc/testsuite/gfortran.dg/alloc_alloc_expr_1.f90	(Revision 119989)
+++ gcc/testsuite/gfortran.dg/alloc_alloc_expr_1.f90	(Arbeitskopie)
@@ -24,6 +24,8 @@
 
   ALLOCATE(PTR,ALLOCS(PTR)) ! { dg-error "same ALLOCATE statement" }
 
-  print *, 'This program has three errors', PTR, ALLOC(1)
+  deallocate(ALLOCS(1)) ! { dg-error "must be ALLOCATABLE or a POINTER" }
+
+  print *, 'This program has four errors', PTR, ALLOC(1)
 
 end program fc011
Index: gcc/testsuite/gfortran.dg/allocatable_dummy_2.f90
===================================================================
--- gcc/testsuite/gfortran.dg/allocatable_dummy_2.f90	(Revision 119989)
+++ gcc/testsuite/gfortran.dg/allocatable_dummy_2.f90	(Arbeitskopie)
@@ -16,13 +16,13 @@
     subroutine init2(x)
         integer, allocatable, intent(in) :: x(:)
 
-        allocate(x(3)) ! { dg-error "Can't allocate" }
+        allocate(x(3)) ! { dg-error "Cannot allocate" }
     end subroutine init2
 
     subroutine kill(x)
         integer, allocatable, intent(in) :: x(:)
         
-        deallocate(x) ! { dg-error "Can't deallocate" }
+        deallocate(x) ! { dg-error "Cannot deallocate" }
     end subroutine kill
 
 end program alloc_dummy
Index: gcc/testsuite/gfortran.dg/pointer_intent_1.f90
===================================================================
--- gcc/testsuite/gfortran.dg/pointer_intent_1.f90	(Revision 0)
+++ gcc/testsuite/gfortran.dg/pointer_intent_1.f90	(Revision 0)
@@ -0,0 +1,71 @@
+! { dg-run }
+! { dg-options "-std=f2003 -fall-intrinsics" }
+! Pointer intent test
+! PR fortran/29624
+!
+! Valid program
+program test
+ implicit none
+ type myT
+   integer          :: x
+   integer, pointer :: point
+ end type myT
+ integer, pointer :: p
+ type(myT), pointer :: t
+ type(myT) :: t2
+ allocate(p,t)
+ allocate(t%point)
+ t%point = 55
+ p = 33
+ call a(p,t)
+ deallocate(p)
+ nullify(p)
+ call a(p,t)
+ call nonpointer(t2)
+contains
+  subroutine a(p,t)
+    integer, pointer,intent(in)    :: p
+    type(myT), pointer, intent(in) :: t
+    integer, pointer :: tmp
+    if(.not.associated(p)) return
+    if(p /= 33) call abort()
+    p = 7
+    if (associated(t)) then
+      ! allocating is valid as we don't change the status
+      ! of the pointer "t", only of it's target
+      t%x = -15
+      if(.not.associated(t%point)) call abort()
+      if(t%point /= 55) call abort()
+      nullify(t%point)
+      allocate(tmp)
+      t%point => tmp
+      deallocate(t%point)
+      t%point => null(t%point)
+      tmp => null(tmp)
+      allocate(t%point)
+      t%point = 27
+      if(t%point /= 27) call abort()
+      if(t%x     /= -15) call abort()
+      call foo(t)
+      if(t%x     /=  32) call abort()
+      if(t%point /= -98) call abort()
+    end if
+    call b(p)
+    if(p /= 5) call abort()
+  end subroutine
+  subroutine b(v)
+    integer, intent(out) :: v
+    v = 5
+  end subroutine b
+  subroutine foo(comp)
+    type(myT), intent(inout) :: comp
+    if(comp%x     /= -15) call abort()
+    !if(comp%point /=  27) call abort()
+    comp%x     = 32
+    comp%point = -98
+  end subroutine foo
+  subroutine nonpointer(t)
+     type(myT), intent(in) :: t
+     t%point = 7
+  end subroutine nonpointer
+end program
Index: gcc/testsuite/gfortran.dg/pointer_intent_2.f90
===================================================================
--- gcc/testsuite/gfortran.dg/pointer_intent_2.f90	(Revision 0)
+++ gcc/testsuite/gfortran.dg/pointer_intent_2.f90	(Revision 0)
@@ -0,0 +1,19 @@
+! { dg-compile }
+! { dg-options "-std=f95" }
+! { dg-shouldfail "Fortran 2003 feature with -std=f95" }
+!
+! Pointer intent test
+! PR fortran/29624
+!
+! Fortran 2003 features in Fortran 95
+program test
+ implicit none
+ integer, pointer :: p
+ allocate(p)
+ p = 33
+ call a(p) ! { dg-error "Type/rank mismatch in argument" }
+contains
+  subroutine a(p)! { dg-error "has no IMPLICIT type" }
+    integer, pointer,intent(in) :: p ! { dg-error "POINTER attribute with INTENT attribute" }
+  end subroutine
+end program
Index: gcc/testsuite/gfortran.dg/pointer_intent_3.f90
===================================================================
--- gcc/testsuite/gfortran.dg/pointer_intent_3.f90	(Revision 0)
+++ gcc/testsuite/gfortran.dg/pointer_intent_3.f90	(Revision 0)
@@ -0,0 +1,41 @@
+! { dg-compile }
+! { dg-options "-std=f2003 -fall-intrinsics" }
+! { dg-shouldfail "Invalid code" }
+!
+! Pointer intent test
+! PR fortran/29624
+!
+! Valid program
+program test
+ implicit none
+ type myT
+    integer :: j = 5
+    integer, pointer :: jp => null()
+ end type myT
+ integer, pointer :: p
+ type(myT) :: t
+ call a(p)
+ call b(t)
+contains
+  subroutine a(p)
+    integer, pointer,intent(in) :: p
+    p => null(p)! { dg-error "Cannot assign to INTENT\\(IN\\) variable" }
+    nullify(p)  ! { dg-error "Cannot assign to INTENT\\(IN\\) variable" }
+    allocate(p) ! { dg-error "Cannot allocate INTENT\\(IN\\) variable" }
+    call c(p)   ! { dg-error "is INTENT\\(IN\\) while interface specifies INTENT\\(INOUT\\)" }
+    deallocate(p) ! { dg-error "Cannot deallocate INTENT\\(IN\\) variable" }
+  end subroutine
+  subroutine c(p)
+    integer, pointer, intent(inout) :: p
+    nullify(p)
+  end subroutine c
+  subroutine b(t)
+    type(myT),intent(in) :: t
+    t%jp = 5
+    t%jp => null(t%jp)  ! { dg-error "Cannot assign to INTENT\\(IN\\) variable" }
+    nullify(t%jp) ! { dg-error "Cannot assign to INTENT\\(IN\\) variable" }
+    t%j = 7 ! { dg-error "Cannot assign to INTENT\\(IN\\) variable" }
+    allocate(t%jp) ! { dg-error "Cannot allocate INTENT\\(IN\\) variable" }
+    deallocate(t%jp) ! { dg-error "Cannot deallocate INTENT\\(IN\\) variable" }
+  end subroutine b
+end program

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