dump-parse-tree.c (show_char_const): New function.

fortran/
* dump-parse-tree.c (show_char_const): New function.
(gfc_show_expr): Use it.
* expr.c (find_substring_ref): Rework to not keep characters
dangling beyond end of string.
testsuite/
* gfortran.dg/substr_6.f90: New test.

From-SVN: r128027

gcc/fortran/ChangeLog

+2007-09-02  Tobias Schluter  <tobi@gcc.gnu.org>
+
+	* dump-parse-tree.c (show_char_const): New function.
+	(gfc_show_expr): Use it.
+	* expr.c (find_substring_ref): Rework to not keep characters
+	dangling beyond end of string.
+
 2007-09-02  H.J. Lu  <hongjiu.lu@intel.com>
 
 	PR fortran/33276

gcc/fortran/dump-parse-tree.c

@@ -290,6 +290,28 @@ gfc_show_constructor (gfc_constructor *c)
 }
 
 
+static void
+show_char_const (const char *c, int length)
+{
+  int i;
+
+  gfc_status_char ('\'');
+  for (i = 0; i < length; i++)
+    {
+      if (c[i] == '\'')
+	gfc_status ("''");
+      else if (ISPRINT (c[i]))
+	gfc_status_char (c[i]);
+      else
+	{
+	  gfc_status ("' // ACHAR(");
+	  printf ("%d", c[i]);
+	  gfc_status (") // '");
+	}
+    }
+  gfc_status_char ('\'');
+}
+
 /* Show an expression.  */
 
 void
@@ -307,16 +329,7 @@ gfc_show_expr (gfc_expr *p)
   switch (p->expr_type)
     {
     case EXPR_SUBSTRING:
-      c = p->value.character.string;
-
-      for (i = 0; i < p->value.character.length; i++, c++)
-	{
-	  if (*c == '\'')
-	    gfc_status ("''");
-	  else
-	    gfc_status ("%c", *c);
-	}
-
+      show_char_const (p->value.character.string, p->value.character.length);
       gfc_show_ref (p->ref);
       break;
 
@@ -362,20 +375,8 @@ gfc_show_expr (gfc_expr *p)
 	  break;
 
 	case BT_CHARACTER:
-	  c = p->value.character.string;
-
-	  gfc_status_char ('\'');
-
-	  for (i = 0; i < p->value.character.length; i++, c++)
-	    {
-	      if (*c == '\'')
-		gfc_status ("''");
-	      else
-		gfc_status_char (*c);
-	    }
-
-	  gfc_status_char ('\'');
-
+	  show_char_const (p->value.character.string, 
+			   p->value.character.length);
 	  break;
 
 	case BT_COMPLEX:

gcc/fortran/expr.c

@@ -1329,6 +1329,7 @@ find_substring_ref (gfc_expr *p, gfc_expr **newp)
 {
   int end;
   int start;
+  int length;
   char *chr;
 
   if (p->ref->u.ss.start->expr_type != EXPR_CONSTANT
@@ -1336,13 +1337,16 @@ find_substring_ref (gfc_expr *p, gfc_expr **newp)
     return FAILURE;
 
   *newp = gfc_copy_expr (p);
-  chr = p->value.character.string;
+  gfc_free ((*newp)->value.character.string);
+
   end = (int) mpz_get_ui (p->ref->u.ss.end->value.integer);
   start = (int) mpz_get_ui (p->ref->u.ss.start->value.integer);
+  length = end - start + 1;
 
-  (*newp)->value.character.length = end - start + 1;
-  strncpy ((*newp)->value.character.string, &chr[start - 1],
-	   (*newp)->value.character.length);
+  chr = (*newp)->value.character.string = gfc_getmem (length + 1);
+  (*newp)->value.character.length = length;
+  memcpy (chr, &p->value.character.string[start - 1], length);
+  chr[length] = '\0';
   return SUCCESS;
 }
 

gcc/testsuite/ChangeLog

+2007-09-02  Tobias Schluter  <tobi@gcc.gnu.org>
+
+	* gfortran.dg/substr_6.f90: New test.
+
 2007-09-02  Paolo Carlini  <pcarlini@suse.de>
 
 	PR c++/33208

gcc/testsuite/gfortran.dg/substr_6.f90

+! { dg-do run }
+! Check that NULs don't mess up constant substring simplification
+CHARACTER(5), parameter :: c0(1) = (/ "123" // ACHAR(0) // "5" /)
+CHARACTER*5 c(1)
+CHARACTER(1), parameter :: c1(5) = (/ "1", "2", "3", ACHAR(0), "5" /)
+
+c = c0(1)(-5:-8)
+if (c(1) /= "     ") call abort()
+c = (/ c0(1)(1:5) /)
+do i=1,5
+   if (c(1)(i:i) /= c1(i)) call abort()
+end do
+print *, c(1)
+end