Enable inherited submodule access of private/protected variables from parent

Author: gklimowicz

tools/flang1/flang1exe/semsym.c

@@ -224,6 +224,9 @@ sym_in_scope(int first, OVCLASS overloadclass, int *paliassym, int *plevel,
         } else if (scope->kind == SCOPE_USE &&
                    (PRIVATEG(sptr) || PRIVATEG(sptrloop))) {
           found = TRUE; /* private module variable */
+          /* private module variables are visible to inherited submodules*/
+          if (is_used_by_submod(gbl.currsub, sptr))
+            return sptr;
         }
         if (!found) { /* not found in 'except' list */
           if (STYPEG(sptr) == ST_ALIAS)

tools/flang1/flang1exe/semutil.c

@@ -1691,8 +1691,12 @@ mklvalue(SST *stkptr, int stmt_type)
     else
       set_assn(sptr);
   } else if (stmt_type == 1 && !POINTERG(lval ? memsym_of_ast(lval) : sptr)) {
-    if (!lval)
-      set_assn(sptr);
+    if (!lval) {
+      /* it's legal for inherited submodules to access protected variables 
+         defined parent modules, otherwise it's illegal */
+      if (!is_used_by_submod(gbl.currsub, sptr))
+        set_assn(sptr);
+    }
     else
       set_assn(sym_of_ast(lval));
   } else if (stmt_type == 3)

tools/flang1/flang1exe/symtab.c

@@ -3344,12 +3344,12 @@ map_initsym(int oldsym, int old_firstosym)
   return 0;
 }
 
-/*
-  Convert two dollar signs to a hyphen. Especially used for the
-  submodule *.mod file renaming:
-  ancestor$$submod.mod -> ancestor-submod.mod
+/** \brief Convert two dollar signs to a hyphen. Especially used for the
+           submodule *.mod file renaming:
+           ancestor$$submod.mod -> ancestor-submod.mod
  */
-void convert_2dollar_signs_to_hyphen(char *name) {
+void 
+convert_2dollar_signs_to_hyphen(char *name) {
   char *p, *q;
   p = q = name;
   while (*q) {
@@ -3362,3 +3362,13 @@ void convert_2dollar_signs_to_hyphen(char *name) {
   *p = *q;
 }
 
+/** \brief Used for check whether sym2 used inside the scope of sym1 is defined in 
+           parent modules (SCOPEG(sym2)) and used by inherited submodules 
+           ENCLFUNCG(sym1).
+ */
+bool 
+is_used_by_submod(SPTR sym1, SPTR sym2) {
+  return STYPEG(ENCLFUNCG(sym1)) == ST_MODULE && 
+         STYPEG(SCOPEG(sym2)) == ST_MODULE &&
+         SCOPEG(sym2) == ANCESTORG(ENCLFUNCG(sym1));
+}

tools/flang1/utils/symtab/symtab.in.h

@@ -478,5 +478,6 @@ typedef enum CMP_INTERFACE_FLAGS {
 bool compatible_characteristics(int psptr, int psptr2,
                                 cmp_interface_flags flag);
 bool cmp_interfaces_strict(SPTR sym1, SPTR sym2, cmp_interface_flags flag);
+bool is_used_by_submod(SPTR sym1, SPTR sym2);
 
 #endif // SYMTAB_H_

tools/flang1/utils/symtab/symtab.n

@@ -473,8 +473,8 @@ Flags3
 .ul
 Other Fields
 .SE ENCLFUNC w28 SPTR
-Symbol table pointer to the enclosing function for
-this variable.
+Symbol table pointer to the enclosing function (or module) for
+this variable (or subprogram).
 Zero for variables with
 .cw SCOPE
 equal to 0.