From f59d6b8f6ab79a0ed1e6d1e473f325cc5d8974c3 Mon Sep 17 00:00:00 2001
From: acqn <acqn163@outlook.com>
Date: Mon, 3 Aug 2020 01:31:52 +0800
Subject: [PATCH] Redefining enums/structs/unions of 0 size is no longer
 treated as declarations and thus forbidden.

---
 src/cc65/declare.c |  4 ++--
 src/cc65/symtab.c  | 20 +++++++++++++-------
 2 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/src/cc65/declare.c b/src/cc65/declare.c
index 5ecfeb04f..5f5fdeac4 100644
--- a/src/cc65/declare.c
+++ b/src/cc65/declare.c
@@ -920,7 +920,7 @@ NextMember: if (CurTok.Tok != TOK_COMMA) {
     LeaveStructLevel ();
 
     /* Make a real entry from the forward decl and return it */
-    return AddStructSym (Name, SC_UNION, UnionSize, FieldTab);
+    return AddStructSym (Name, SC_UNION | SC_DEF, UnionSize, FieldTab);
 }
 
 
@@ -1102,7 +1102,7 @@ NextMember: if (CurTok.Tok != TOK_COMMA) {
     LeaveStructLevel ();
 
     /* Make a real entry from the forward decl and return it */
-    return AddStructSym (Name, SC_STRUCT, StructSize, FieldTab);
+    return AddStructSym (Name, SC_STRUCT | SC_DEF, StructSize, FieldTab);
 }
 
 
diff --git a/src/cc65/symtab.c b/src/cc65/symtab.c
index a673bc3dd..08c909121 100644
--- a/src/cc65/symtab.c
+++ b/src/cc65/symtab.c
@@ -52,13 +52,13 @@
 #include "declare.h"
 #include "error.h"
 #include "funcdesc.h"
+#include "function.h"
 #include "global.h"
+#include "input.h"
 #include "stackptr.h"
 #include "symentry.h"
 #include "typecmp.h"
 #include "symtab.h"
-#include "function.h"
-#include "input.h"
 
 
 
@@ -728,6 +728,10 @@ SymEntry* AddEnumSym (const char* Name, const Type* Type, SymTable* Tab)
         Entry->V.E.SymTab = Tab;
         Entry->V.E.Type   = Type;
 
+        if (Type != 0) {
+            Entry->Flags |= SC_DEF;
+        }
+
         /* Add it to the current table */
         AddSymEntry (CurTagTab, Entry);
     }
@@ -738,11 +742,12 @@ SymEntry* AddEnumSym (const char* Name, const Type* Type, SymTable* Tab)
 
 
 
-SymEntry* AddStructSym (const char* Name, unsigned Type, unsigned Size, SymTable* Tab)
+SymEntry* AddStructSym (const char* Name, unsigned Flags, unsigned Size, SymTable* Tab)
 /* Add a struct/union entry and return it */
 {
     SymTable* CurTagTab = TagTab;
     SymEntry* Entry;
+    unsigned Type = (Flags & SC_TYPEMASK);
 
     /* Type must be struct or union */
     PRECONDITION (Type == SC_STRUCT || Type == SC_UNION);
@@ -756,13 +761,14 @@ SymEntry* AddStructSym (const char* Name, unsigned Type, unsigned Size, SymTable
             /* Existing symbol is not a struct */
             Error ("Symbol '%s' is already different kind", Name);
             Entry = 0;
-        } else if (Size > 0 && Entry->V.S.Size > 0) {
+        } else if ((Entry->Flags & Flags & SC_DEF) == SC_DEF) {
             /* Both structs are definitions. */
             Error ("Multiple definition for '%s'", Name);
             Entry = 0;
         } else {
-            /* Define the struct size if it is given */
-            if (Size > 0) {
+            /* Define the struct size if it is a definition */
+            if ((Flags & SC_DEF) == SC_DEF) {
+                Entry->Flags      = Flags;
                 Entry->V.S.SymTab = Tab;
                 Entry->V.S.Size   = Size;
             }
@@ -777,7 +783,7 @@ SymEntry* AddStructSym (const char* Name, unsigned Type, unsigned Size, SymTable
     if (Entry == 0) {
 
         /* Create a new entry */
-        Entry = NewSymEntry (Name, Type);
+        Entry = NewSymEntry (Name, Flags);
 
         /* Set the struct data */
         Entry->V.S.SymTab = Tab;