diff --git a/lips/Dumper.lua b/lips/Dumper.lua
index 5a84302..6d90537 100644
--- a/lips/Dumper.lua
+++ b/lips/Dumper.lua
@@ -33,16 +33,16 @@ function Dumper:push_instruction(t)
     self:advance(4)
 end
 
-function Dumper:add_instruction_j(line, o, T)
-    self:push_instruction{line=line, o, T}
+function Dumper:add_instruction_j(fn, line, o, T)
+    self:push_instruction{fn=fn, line=line, o, T}
 end
 
-function Dumper:add_instruction_i(line, o, s, t, i)
-    self:push_instruction{line=line, o, s, t, i}
+function Dumper:add_instruction_i(fn, line, o, s, t, i)
+    self:push_instruction{fn=fn, line=line, o, s, t, i}
 end
 
-function Dumper:add_instruction_r(line, o, s, t, d, f, c)
-    self:push_instruction{line=line, o, s, t, d, f, c}
+function Dumper:add_instruction_r(fn, line, o, s, t, d, f, c)
+    self:push_instruction{fn=fn, line=line, o, s, t, d, f, c}
 end
 
 function Dumper:add_label(name)
@@ -58,6 +58,8 @@ function Dumper:add_bytes(line, ...)
         t = {}
         t.kind = 'bytes'
         t.size = 0
+        t.fn = self.fn
+        t.line = self.line
     end
     t.line = line
     for _, b in ipairs{...} do
@@ -70,9 +72,12 @@ function Dumper:add_bytes(line, ...)
     self:advance(t.size)
 end
 
-function Dumper:add_directive(line, name, a, b)
+function Dumper:add_directive(fn, line, name, a, b)
+    self.fn = fn
+    self.line = line
     local t = {}
-    t.line = line
+    t.fn = self.fn
+    t.line = self.line
     if name == 'BYTE' then
         self:add_bytes(line, a % 0x100)
     elseif name == 'HALFWORD' then
@@ -124,7 +129,6 @@ function Dumper:add_directive(line, name, a, b)
 end
 
 function Dumper:desym(tok)
-    -- FIXME: errors can give wrong filename
     if type(tok[2]) == 'number' then
         return tok[2]
     elseif tok[1] == 'LABELSYM' then
@@ -254,9 +258,9 @@ end
 function Dumper:dump()
     self.pos = self.options.offset or 0
     for i, t in ipairs(self.commands) do
-        if t.line == nil then
-            error('Internal Error: no line number available')
-        end
+        assert(t.fn, 'Internal Error: no file name available')
+        assert(t.line, 'Internal Error: no line number available')
+        self.fn = t.fn
         self.line = t.line
         if t.kind == 'instruction' then
             local uw, lw = self:dump_instruction(t)
diff --git a/lips/Parser.lua b/lips/Parser.lua
index 64eaea6..03d1e04 100644
--- a/lips/Parser.lua
+++ b/lips/Parser.lua
@@ -69,36 +69,38 @@ end
 function Parser:directive()
     local name = self.tok
     self:advance()
-    local line = self.line
+    local function add(...)
+        self.dumper:add_directive(self.fn, self.line, ...)
+    end
     if name == 'ORG' then
-        self.dumper:add_directive(line, name, self:number())
+        add(name, self:number())
     elseif name == 'ALIGN' or name == 'SKIP' then
         if self:is_EOL() and name == 'ALIGN' then
-            self.dumper:add_directive(line, name, 0)
+            add(name, 0)
         else
             local size = self:number()
             if self:is_EOL() then
-                self.dumper:add_directive(line, name, size)
+                add(name, size)
             else
                 self:optional_comma()
-                self.dumper:add_directive(line, name, size, self:number())
+                add(name, size, self:number())
             end
             self:expect_EOL()
         end
     elseif name == 'BYTE' or name == 'HALFWORD' then
-        self.dumper:add_directive(line, name, self:number())
+        add(name, self:number())
         while not self:is_EOL() do
             self:advance()
             self:optional_comma()
-            self.dumper:add_directive(line, name, self:number())
+            add(name, self:number())
         end
         self:expect_EOL()
     elseif name == 'WORD' then -- allow labels in word directives
-        self.dumper:add_directive(line, name, self:const()[2])
+        add(name, self:const()[2])
         while not self:is_EOL() do
             self:advance()
             self:optional_comma()
-            self.dumper:add_directive(line, name, self:const()[2])
+            add(name, self:const()[2])
         end
         self:expect_EOL()
     elseif name == 'INC' then
@@ -106,10 +108,10 @@ function Parser:directive()
     elseif name == 'ASCII' or name == 'ASCIIZ' then
         local bytes = self:string()
         for i, number in ipairs(bytes) do
-            self.dumper:add_directive(line, 'BYTE', number)
+            add('BYTE', number)
         end
         if name == 'ASCIIZ' then
-            self.dumper:add_directive(line, 'BYTE', 0)
+            add('BYTE', 0)
         end
         self:expect_EOL()
     elseif name == 'INCBIN' then
@@ -246,7 +248,7 @@ function Parser:format_out_raw(outformat, first, args, const, formatconst)
     if f == nil then
         error('Internal Error: invalid output formatting string', 1)
     end
-    f(self.dumper, self.line, first, out[1], out[2], out[3], out[4], out[5])
+    f(self.dumper, self.fn, self.line, first, out[1], out[2], out[3], out[4], out[5])
 end
 
 function Parser:format_out(t, args)
@@ -311,12 +313,12 @@ function Parser:tokenize(asm)
     end)
 
     local function lex()
-        local t = {}
         local ok, a, b, c, d = coroutine.resume(routine)
         if not ok then
             a = a or 'Internal Error: lexer coroutine has stopped'
             error(a)
         end
+        local t = {}
         t.tt = a
         t.tok = b
         t.fn = c