PR fortran/95090 - ICE: identifier overflow

For long module name, derive type and component name, the generated
name-mangled symbol did not fit into a buffer when coarrays were
enabled.  Provide sufficiently large temporary.

2020-05-27  Harald Anlauf  <anlauf@gmx.de>

gcc/fortran/
	PR fortran/95090
	* iresolve.c (gfc_get_string): Enlarge temporary for
	name-mangling.

gcc/testsuite/
	PR fortran/95090
	* gfortran.dg/pr95090.f90: New test.

(cherry picked from commit c949ec9c4e88d2ff6dbd5b179abddf3703129577)

gcc/fortran/iresolve.c

@@ -47,7 +47,8 @@ along with GCC; see the file COPYING3.  If not see
 const char *
 gfc_get_string (const char *format, ...)
 {
-  char temp_name[128];
+  /* Provide sufficient space to hold "_F.caf_token__symbol_MOD_symbol".  */
+  char temp_name[14 + GFC_MAX_SYMBOL_LEN + 5 + GFC_MAX_SYMBOL_LEN + 1];
   const char *str;
   va_list ap;
   tree ident;

gcc/testsuite/gfortran.dg/pr95090.f90

+! { dg-do compile }
+! { dg-options "-fcoarray=lib -fsecond-underscore" }
+! PR fortran/95090 - ICE: identifier overflow
+
+module m2345678901234567890123456789012345678901234567890123456789_123
+  type t2345678901234567890123456789012345678901234567890123456789_123 &
+      (n2345678901234567890123456789012345678901234567890123456789_123)
+     integer, len :: n2345678901234567890123456789012345678901234567890123456789_123 = 8
+  end type
+  integer :: a2345678901234567890123456789012345678901234567890123456789_123
+  integer :: b2345678901234567890123456789012345678901234567890123456789_123(3)[*]
+  data b2345678901234567890123456789012345678901234567890123456789_123 /1,2,3/
+contains
+  subroutine s2345678901234567890123456789012345678901234567890123456789_123
+    type(t2345678901234567890123456789012345678901234567890123456789_123 &
+        (n2345678901234567890123456789012345678901234567890123456789_123)) :: &
+         z2345678901234567890123456789012345678901234567890123456789_123
+   end
+end