varargs: cast __builtin_va_list to (char*); __builtin_memset can't ha…

…ndle uninitialized __builtin_va_list directly

src/compiler/ast-misc.bas

@@ -1281,3 +1281,27 @@ function astIsRelationalBop( byval n as ASTNODE ptr ) as integer
 		function = astOpIsRelational( n->op.op )
 	end if
 end function
+
+function astIsBuiltinValistCarray( byval n as ASTNODE ptr ) as integer
+	function = FALSE
+
+	assert( n <> NULL )
+
+	var subtype = astGetSubtype( n )
+
+	'' !!! TODO !!!
+	'' replace this with a faster check
+
+	if( subtype ) then
+		select case typeGetDtOnly( symbGetFullType( subtype ) )
+		case FB_DATATYPE_STRUCT
+			if( subtype->id.alias ) then
+				select case *subtype->id.alias
+				case "__va_list", "__va_list_tag"
+					function = TRUE
+				end select
+			end if
+		end select
+	end if
+
+end function

src/compiler/ast-node-mem.bas

@@ -35,10 +35,19 @@ function astNewMEM _
 	'' the adress-of and let emit() do the rest, or if blkmaxlen = 0,
 	'' then emit() always handles it, even when lgt=0
 	if( (lgt > blkmaxlen) or (blkmaxlen = 0) ) then
-		l = astNewADDROF( l )
+
+	if( astIsBuiltinValistCarray( l ) ) then
+			l = astNewDEREF( astNewCONV( typeMultAddrOf( FB_DATATYPE_UBYTE, 2 ), NULL, astNewAddrof( l ) ) )
+		else
+			l = astNewADDROF( l )
+		end if
 
 		if( op = AST_OP_MEMMOVE ) then
-			r = astNewADDROF( r )
+			if( astIsBuiltinValistCarray( r ) ) then
+				r = astNewDEREF( astNewCONV( typeMultAddrOf( FB_DATATYPE_UBYTE, 2 ), NULL, astNewAddrof( r ) ) )
+			else
+				r = astNewADDROF( r )
+			end if
 		end if
 	end if
 

src/compiler/ast.bi

@@ -1332,6 +1332,7 @@ declare sub astSetType _
 declare function astSizeOf( byval n as ASTNODE ptr, byref is_fixlenstr as integer = FALSE ) as longint
 declare function astIsAccessToLocal( byval expr as ASTNODE ptr ) as integer
 declare function astIsRelationalBop( byval n as ASTNODE ptr ) as integer
+declare function astIsBuiltinValistCarray( byval n as ASTNODE ptr ) as integer
 
 declare function astGetOFFSETChildOfs( byval l as ASTNODE ptr ) as longint