Increase GFC_MAX_MANGLED_SYMBOL_LEN to handle submodule names.

        PR fortran/93461
        * trans.h: Increase GFC_MAX_MANGLED_SYMBOL_LEN to
        GFC_MAX_SYMBOL_LEN*3+5 to allow for inclusion of submodule name,
        plus the "." between module and submodule names.
        * gfortran.dg/pr93461.f90: New test.

gcc/fortran/ChangeLog

 2020-01-28  Andrew Benson  <abensonca@gmail.com>
 
+        PR fortran/93461
+        * trans.h: Increase GFC_MAX_MANGLED_SYMBOL_LEN to
+        GFC_MAX_SYMBOL_LEN*3+5 to allow for inclusion of submodule name,
+        plus the "." between module and submodule names.
+        * gfortran.dg/pr93461.f90: New test.
+
+2020-01-28  Andrew Benson  <abensonca@gmail.com>
+
 	PR fortran/93473
 	* parse.c: Increase length of char variables to allow them to hold
 	a concatenated module + submodule name.

gcc/fortran/trans.h

@@ -23,8 +23,8 @@ along with GCC; see the file COPYING3.  If not see
 
 #include "predict.h"  /* For enum br_predictor and PRED_*.  */
 
-/* Mangled symbols take the form __module__name.  */
-#define GFC_MAX_MANGLED_SYMBOL_LEN  (GFC_MAX_SYMBOL_LEN*2+4)
+/* Mangled symbols take the form __module__name or __module.submodule__name.  */
+#define GFC_MAX_MANGLED_SYMBOL_LEN  (GFC_MAX_SYMBOL_LEN*3+5)
 
 /* Struct for holding a block of statements.  It should be treated as an
    opaque entity and not modified directly.  This allows us to change the

gcc/testsuite/gfortran.dg/pr93461.f90

+! { dg-do compile }
+! PR fortran/93461
+module aModuleWithAnAllowedName
+  interface
+     module subroutine aShortName()
+     end subroutine aShortName
+  end interface
+end module aModuleWithAnAllowedName
+
+submodule (aModuleWithAnAllowedName) aSubmoduleWithAVeryVeryVeryLongButEntirelyLegalName
+contains
+  subroutine aShortName()
+    call aSubroutineWithAVeryLongNameThatWillCauseAProblem()
+    call aSubroutineWithAVeryLongNameThatWillCauseAProblemAlso()
+  end subroutine aShortName
+  
+  subroutine aSubroutineWithAVeryLongNameThatWillCauseAProblem()
+  end subroutine aSubroutineWithAVeryLongNameThatWillCauseAProblem
+
+  subroutine aSubroutineWithAVeryLongNameThatWillCauseAProblemAlso()
+  end subroutine aSubroutineWithAVeryLongNameThatWillCauseAProblemAlso  
+end submodule aSubmoduleWithAVeryVeryVeryLongButEntirelyLegalName