handle macro symbol redecl

Author: Emmankoko

compiler/src/dmd/backend/var.d

@@ -164,6 +164,7 @@ int controlc_saw = 0;              /* a control C was seen         */
 symtab_t globsym;               /* global symbol table                  */
 Pstate pstate;                  // parser state
 Cstate cstate;                  // compiler state
+const(char)[][] gCsym;           // hash table for C symbol lookup
 
 uint numcse;        // number of common subexpressions
 

compiler/src/dmd/glue/toobj.d

@@ -81,6 +81,7 @@ import dmd.backend.obj;
 import dmd.backend.oper;
 import dmd.backend.ty;
 import dmd.backend.type;
+import dmd.backend.var;
 
 package(dmd.glue):
 
@@ -439,6 +440,19 @@ void toObjFile(Dsymbol ds, bool multiobj)
 
         override void visit(VarDeclaration vd)
         {
+            static bool symbol_search(VarDeclaration vd)
+            {
+                auto id = vd.ident.toString();
+
+                auto length = gCsym.length;
+                foreach(ident; gCsym)
+                {
+                    if (id == ident)
+                        return true;
+                }
+                gCsym ~= id;
+                return false;
+            }
 
             //printf("VarDeclaration.toObjFile(%p '%s' type=%s) visibility %d\n", vd, vd.toChars(), vd.type.toChars(), vd.visibility);
             //printf("\talign = %d\n", vd.alignment);
@@ -464,6 +478,9 @@ void toObjFile(Dsymbol ds, bool multiobj)
             if (!vd.isDataseg() || vd.storage_class & STC.extern_)
                 return;
 
+            if (vd.isCmacro && symbol_search(vd)) // true ==> symbol exists
+                return;
+
             Symbol* s = toSymbol(vd);
             const sz64 = vd.type.size(vd.loc);
             if (sz64 == SIZE_INVALID)