diff --git a/src/codegen/codegen.ml b/src/codegen/codegen.ml
index 00ee5968e28..9c0881c43ce 100644
--- a/src/codegen/codegen.ml
+++ b/src/codegen/codegen.ml
@@ -418,13 +418,12 @@ end
 	Build a default safe-cast expression :
 	{ var $t = <e>; if( Std.is($t,<t>) ) $t else throw "Class cast error"; }
 *)
-let default_cast ?(vtmp="$t") com e texpr t p =
-	let api = com.basic in
+let default_cast ?(vtmp="$t") api std e texpr t p =
 	let vtmp = alloc_var VGenerated vtmp e.etype e.epos in
 	let var = mk (TVar (vtmp,Some e)) api.tvoid p in
 	let vexpr = mk (TLocal vtmp) e.etype p in
 	let texpr = Texpr.Builder.make_typeexpr texpr p in
-	let is = Texpr.Builder.resolve_and_make_static_call com.std "isOfType" [vexpr;texpr] p in
+	let is = Texpr.Builder.resolve_and_make_static_call std "isOfType" [vexpr;texpr] p in
 	let enull = Texpr.Builder.make_null vexpr.etype p in
 	let eop = Texpr.Builder.binop OpEq vexpr enull api.tbool p in
 	let echeck = Texpr.Builder.binop OpBoolOr is eop api.tbool p in
@@ -453,12 +452,12 @@ module UnificationCallback = struct
 			List.map (fun e -> f e t_dynamic) el
 end;;
 
-let interpolate_code com code tl f_string f_expr p =
+let interpolate_code error code tl f_string f_expr p =
 	let exprs = Array.of_list tl in
 	let i = ref 0 in
 	let err msg =
 		let pos = { p with pmin = p.pmin + !i } in
-		com.error msg pos
+		error msg pos
 	in
 	let regex = Str.regexp "[{}]" in
 	let rec loop m = match m with
@@ -487,12 +486,6 @@ let interpolate_code com code tl f_string f_expr p =
 	in
 	loop (Str.full_split regex code)
 
-let map_source_header com f =
-	match Common.defined_value_safe com Define.SourceHeader with
-	| "" -> ()
-	| s -> f s
-
-
 (* Static extensions for classes *)
 module ExtClass = struct
 	let add_static_init c cf e p =
diff --git a/src/compiler/generate.ml b/src/compiler/generate.ml
index ede254bec78..e40fee92022 100644
--- a/src/compiler/generate.ml
+++ b/src/compiler/generate.ml
@@ -174,11 +174,11 @@ let generate ctx tctx ext actx =
 			with Not_found ->
 				None
 			in
-			Genswf.generate header,"swf"
+			Genswf.generate header com.Common.native_libs.swf_libs com.Common.flash_version,"swf"
 		| Neko ->
-			Genneko.generate,"neko"
+			Genneko.generate com.neko_lib_paths,"neko"
 		| Js ->
-			Genjs.generate,"js"
+			Genjs.generate com.js_gen,"js"
 		| Lua ->
 			Genlua.generate,"lua"
 		| Php ->
@@ -201,7 +201,7 @@ let generate ctx tctx ext actx =
 		else begin
 			Common.log com ("Generating " ^ name ^ ": " ^ com.file);
 			let t = Timer.timer ["generate";name] in
-			generate com;
+			generate (Common.to_gctx com);
 			t()
 		end
 	end
diff --git a/src/context/common.ml b/src/context/common.ml
index 6cb3fb0ea22..eaf0048645e 100644
--- a/src/context/common.ml
+++ b/src/context/common.ml
@@ -348,11 +348,6 @@ class virtual abstract_hxb_lib = object(self)
 	method virtual get_string_pool : string -> string array option
 end
 
-type context_main = {
-	mutable main_class : path option;
-	mutable main_expr : texpr option;
-}
-
 type context = {
 	compilation_step : int;
 	mutable stage : compiler_stage;
@@ -371,15 +366,15 @@ type context = {
 	mutable config : platform_config;
 	empty_class_path : ClassPath.class_path;
 	class_paths : ClassPaths.class_paths;
-	main : context_main;
+	main : Gctx.context_main;
 	mutable package_rules : (string,package_rule) PMap.t;
 	mutable report_mode : report_mode;
 	(* communication *)
 	mutable print : string -> unit;
-	mutable error : ?depth:int -> string -> pos -> unit;
+	mutable error : Gctx.error_function;
 	mutable error_ext : Error.error -> unit;
 	mutable info : ?depth:int -> ?from_macro:bool -> string -> pos -> unit;
-	mutable warning : ?depth:int -> ?from_macro:bool -> warning -> Warning.warning_option list list -> string -> pos -> unit;
+	mutable warning : Gctx.warning_function;
 	mutable warning_options : Warning.warning_option list list;
 	mutable get_messages : unit -> compiler_message list;
 	mutable filter_messages : (compiler_message -> bool) -> unit;
@@ -433,6 +428,32 @@ type context = {
 	mutable hxb_writer_config : HxbWriterConfig.t option;
 }
 
+let to_gctx com = {
+	Gctx.platform = com.platform;
+	defines = com.defines;
+	basic = com.basic;
+	class_paths = com.class_paths;
+	run_command = com.run_command;
+	run_command_args = com.run_command_args;
+	warning = com.warning;
+	error = com.error;
+	print = com.print;
+	debug = com.debug;
+	file = com.file;
+	version = com.version;
+	features = com.features;
+	modules = com.modules;
+	main = com.main;
+	types = com.types;
+	resources = com.resources;
+	native_libs = (match com.platform with
+		| Jvm -> (com.native_libs.java_libs :> NativeLibraries.native_library_base list)
+		| Flash -> (com.native_libs.swf_libs  :> NativeLibraries.native_library_base list)
+		| _ -> []);
+	include_files = com.include_files;
+	std = com.std;
+}
+
 let enter_stage com stage =
 	(* print_endline (Printf.sprintf "Entering stage %s" (s_compiler_stage stage)); *)
 	com.stage <- stage
@@ -522,9 +543,6 @@ let defines_for_external ctx =
 			| split -> PMap.add (String.concat "-" split) v added_underscore;
 	) ctx.defines.values PMap.empty
 
-let get_es_version com =
-	try int_of_string (defined_value com Define.JsEs) with _ -> 0
-
 let short_platform_name = function
 	| Cross -> "x"
 	| Js -> "js"
@@ -587,7 +605,7 @@ let get_config com =
 		(* impossible to reach. see update_platform_config *)
 		raise Exit
 	| Js ->
-		let es6 = get_es_version com >= 6 in
+		let es6 = Gctx.get_es_version com.defines >= 6 in
 		{
 			default_config with
 			pf_static = false;
@@ -927,27 +945,6 @@ let flash_versions = List.map (fun v ->
 	v, string_of_int maj ^ (if min = 0 then "" else "_" ^ string_of_int min)
 ) [9.;10.;10.1;10.2;10.3;11.;11.1;11.2;11.3;11.4;11.5;11.6;11.7;11.8;11.9;12.0;13.0;14.0;15.0;16.0;17.0;18.0;19.0;20.0;21.0;22.0;23.0;24.0;25.0;26.0;27.0;28.0;29.0;31.0;32.0]
 
-let flash_version_tag = function
-	| 6. -> 6
-	| 7. -> 7
-	| 8. -> 8
-	| 9. -> 9
-	| 10. | 10.1 -> 10
-	| 10.2 -> 11
-	| 10.3 -> 12
-	| 11. -> 13
-	| 11.1 -> 14
-	| 11.2 -> 15
-	| 11.3 -> 16
-	| 11.4 -> 17
-	| 11.5 -> 18
-	| 11.6 -> 19
-	| 11.7 -> 20
-	| 11.8 -> 21
-	| 11.9 -> 22
-	| v when v >= 12.0 && float_of_int (int_of_float v) = v -> int_of_float v + 11
-	| v -> failwith ("Invalid SWF version " ^ string_of_float v)
-
 let update_platform_config com =
 	match com.platform with
 	| CustomTarget _ ->
@@ -1093,90 +1090,6 @@ let hash f =
 	done;
 	if Sys.word_size = 64 then Int32.to_int (Int32.shift_right (Int32.shift_left (Int32.of_int !h) 1) 1) else !h
 
-let url_encode s add_char =
-	let hex = "0123456789ABCDEF" in
-	for i = 0 to String.length s - 1 do
-		let c = String.unsafe_get s i in
-		match c with
-		| 'A'..'Z' | 'a'..'z' | '0'..'9' | '_' | '-' | '.' ->
-			add_char c
-		| _ ->
-			add_char '%';
-			add_char (String.unsafe_get hex (int_of_char c lsr 4));
-			add_char (String.unsafe_get hex (int_of_char c land 0xF));
-	done
-
-let url_encode_s s =
-	let b = Buffer.create 0 in
-	url_encode s (Buffer.add_char b);
-	Buffer.contents b
-
-(* UTF8 *)
-
-let to_utf8 str p =
-	let u8 = try
-		UTF8.validate str;
-		str;
-	with
-		UTF8.Malformed_code ->
-			(* ISO to utf8 *)
-			let b = UTF8.Buf.create 0 in
-			String.iter (fun c -> UTF8.Buf.add_char b (UCharExt.of_char c)) str;
-			UTF8.Buf.contents b
-	in
-	let ccount = ref 0 in
-	UTF8.iter (fun c ->
-		let c = UCharExt.code c in
-		if (c >= 0xD800 && c <= 0xDFFF) || c >= 0x110000 then Error.abort "Invalid unicode char" p;
-		incr ccount;
-		if c > 0x10000 then incr ccount;
-	) u8;
-	u8, !ccount
-
-let utf16_add buf c =
-	let add c =
-		Buffer.add_char buf (char_of_int (c land 0xFF));
-		Buffer.add_char buf (char_of_int (c lsr 8));
-	in
-	if c >= 0 && c < 0x10000 then begin
-		if c >= 0xD800 && c <= 0xDFFF then failwith ("Invalid unicode char " ^ string_of_int c);
-		add c;
-	end else if c < 0x110000 then begin
-		let c = c - 0x10000 in
-		add ((c asr 10) + 0xD800);
-		add ((c land 1023) + 0xDC00);
-	end else
-		failwith ("Invalid unicode char " ^ string_of_int c)
-
-let utf8_to_utf16 str zt =
-	let b = Buffer.create (String.length str * 2) in
-	(try UTF8.iter (fun c -> utf16_add b (UCharExt.code c)) str with Invalid_argument _ | UCharExt.Out_of_range -> ()); (* if malformed *)
-	if zt then utf16_add b 0;
-	Buffer.contents b
-
-let utf16_to_utf8 str =
-	let b = Buffer.create 0 in
-	let add c = Buffer.add_char b (char_of_int (c land 0xFF)) in
-	let get i = int_of_char (String.unsafe_get str i) in
-	let rec loop i =
-		if i >= String.length str then ()
-		else begin
-			let c = get i in
-			if c < 0x80 then begin
-				add c;
-				loop (i + 2);
-			end else if c < 0x800 then begin
-				let c = c lor ((get (i + 1)) lsl 8) in
-				add c;
-				add (c lsr 8);
-				loop (i + 2);
-			end else
-				die "" __LOC__;
-		end
-	in
-	loop 0;
-	Buffer.contents b
-
 let add_diagnostics_message ?(depth = 0) ?(code = None) com s p kind sev =
 	if sev = MessageSeverity.Error then com.has_error <- true;
 	let di = com.shared.shared_display_information in
diff --git a/src/context/nativeLibraries.ml b/src/context/nativeLibraries.ml
index fe7de4b6396..bf922c9e2da 100644
--- a/src/context/nativeLibraries.ml
+++ b/src/context/nativeLibraries.ml
@@ -23,7 +23,7 @@ type native_lib_flags =
 	| FlagIsStd
 	| FlagIsExtern
 
-class virtual ['a,'data] native_library (name : string) (file_path : string) = object(self)
+class virtual native_library_base (name : string) (file_path : string) = object(self)
 	val mutable flags : native_lib_flags list = []
 
 	method add_flag flag = flags <- flag :: flags
@@ -31,6 +31,10 @@ class virtual ['a,'data] native_library (name : string) (file_path : string) = o
 
 	method get_name = name
 	method get_file_path = file_path
+end
+
+class virtual ['a,'data] native_library (name : string) (file_path : string) = object(self)
+	inherit native_library_base name file_path
 
 	method virtual build : path -> pos -> Ast.package option
 	method virtual close : unit
diff --git a/src/context/sourcemaps.ml b/src/context/sourcemaps.ml
index 3dd3e39cb47..761109bd108 100644
--- a/src/context/sourcemaps.ml
+++ b/src/context/sourcemaps.ml
@@ -1,6 +1,6 @@
 open Extlib_leftovers
 open Globals
-open Common
+open Gctx
 
 (**
 	Characters used for base64 VLQ encoding
@@ -127,7 +127,7 @@ class sourcemap_writer (generated_file:string) =
 		output_string channel ("\"sources\":[" ^
 			(String.concat "," (List.map (fun s -> "\"" ^ to_url s ^ "\"") sources)) ^
 			"],\n");
-		if Common.defined com Define.SourceMapContent then begin
+		if Gctx.defined com Define.SourceMapContent then begin
 			output_string channel ("\"sourcesContent\":[" ^
 				(String.concat "," (List.map (fun s -> try "\"" ^ StringHelper.s_escape (Std.input_file ~bin:true s) ^ "\"" with _ -> "null") sources)) ^
 				"],\n");
diff --git a/src/core/stringHelper.ml b/src/core/stringHelper.ml
index 824e8e1aa99..aca5df70c86 100644
--- a/src/core/stringHelper.ml
+++ b/src/core/stringHelper.ml
@@ -1,3 +1,6 @@
+open Globals
+open Extlib_leftovers
+
 let uppercase s =
 	let bytes = Bytes.of_string s in
 	Bytes.iteri
@@ -68,4 +71,88 @@ let extension file =
 		let dot_pos = String.rindex file '.' in
 		String.sub file dot_pos (String.length file - dot_pos)
 	with Not_found ->
-		file
\ No newline at end of file
+		file
+
+(* UTF8 *)
+
+let to_utf8 str p =
+	let u8 = try
+		UTF8.validate str;
+		str;
+	with
+		UTF8.Malformed_code ->
+			(* ISO to utf8 *)
+			let b = UTF8.Buf.create 0 in
+			String.iter (fun c -> UTF8.Buf.add_char b (UCharExt.of_char c)) str;
+			UTF8.Buf.contents b
+	in
+	let ccount = ref 0 in
+	UTF8.iter (fun c ->
+		let c = UCharExt.code c in
+		if (c >= 0xD800 && c <= 0xDFFF) || c >= 0x110000 then failwith "Invalid unicode char";
+		incr ccount;
+		if c > 0x10000 then incr ccount;
+	) u8;
+	u8, !ccount
+
+let utf16_add buf c =
+	let add c =
+		Buffer.add_char buf (char_of_int (c land 0xFF));
+		Buffer.add_char buf (char_of_int (c lsr 8));
+	in
+	if c >= 0 && c < 0x10000 then begin
+		if c >= 0xD800 && c <= 0xDFFF then failwith ("Invalid unicode char " ^ string_of_int c);
+		add c;
+	end else if c < 0x110000 then begin
+		let c = c - 0x10000 in
+		add ((c asr 10) + 0xD800);
+		add ((c land 1023) + 0xDC00);
+	end else
+		failwith ("Invalid unicode char " ^ string_of_int c)
+
+let utf8_to_utf16 str zt =
+	let b = Buffer.create (String.length str * 2) in
+	(try UTF8.iter (fun c -> utf16_add b (UCharExt.code c)) str with Invalid_argument _ | UCharExt.Out_of_range -> ()); (* if malformed *)
+	if zt then utf16_add b 0;
+	Buffer.contents b
+
+let utf16_to_utf8 str =
+	let b = Buffer.create 0 in
+	let add c = Buffer.add_char b (char_of_int (c land 0xFF)) in
+	let get i = int_of_char (String.unsafe_get str i) in
+	let rec loop i =
+		if i >= String.length str then ()
+		else begin
+			let c = get i in
+			if c < 0x80 then begin
+				add c;
+				loop (i + 2);
+			end else if c < 0x800 then begin
+				let c = c lor ((get (i + 1)) lsl 8) in
+				add c;
+				add (c lsr 8);
+				loop (i + 2);
+			end else
+				die "" __LOC__;
+		end
+	in
+	loop 0;
+	Buffer.contents b
+
+let url_encode s add_char =
+	let hex = "0123456789ABCDEF" in
+	for i = 0 to String.length s - 1 do
+		let c = String.unsafe_get s i in
+		match c with
+		| 'A'..'Z' | 'a'..'z' | '0'..'9' | '_' | '-' | '.' ->
+			add_char c
+		| _ ->
+			add_char '%';
+			add_char (String.unsafe_get hex (int_of_char c lsr 4));
+			add_char (String.unsafe_get hex (int_of_char c land 0xF));
+	done
+
+let url_encode_s s =
+	let b = Buffer.create 0 in
+	url_encode s (Buffer.add_char b);
+	Buffer.contents b
diff --git a/src/filters/ES6Ctors.ml b/src/filters/ES6Ctors.ml
index 8dd2b526fcb..82126bb68d0 100644
--- a/src/filters/ES6Ctors.ml
+++ b/src/filters/ES6Ctors.ml
@@ -16,7 +16,7 @@
 	along with this program; if not, write to the Free Software
 	Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  *)
-open Common
+open Gctx
 open Globals
 open Type
 open Texpr.Builder
diff --git a/src/generators/cpp/cppAst.ml b/src/generators/cpp/cppAst.ml
index 9b40716bf34..96707878ff3 100644
--- a/src/generators/cpp/cppAst.ml
+++ b/src/generators/cpp/cppAst.ml
@@ -2,7 +2,6 @@ open Extlib_leftovers
 open Ast
 open Type
 open Error
-open Common
 open Globals
 
 type tcpp =
diff --git a/src/generators/cpp/cppAstTools.ml b/src/generators/cpp/cppAstTools.ml
index ecbdb5c3b70..6e0882f38d0 100644
--- a/src/generators/cpp/cppAstTools.ml
+++ b/src/generators/cpp/cppAstTools.ml
@@ -2,7 +2,6 @@ open Extlib_leftovers
 open Ast
 open Type
 open Error
-open Common
 open Globals
 open CppAst
 open CppTypeUtils
@@ -575,7 +574,7 @@ and type_string_remap remap haxe_type =
 
 and type_string haxe_type =
    type_string_suff "" haxe_type true
-   
+
 and cpp_enum_path_of enum =
    let globalNamespace =
       match get_meta_string enum.e_meta Meta.Native with
@@ -614,7 +613,7 @@ and gen_interface_arg_type_name name opt typ =
 
 and gen_tfun_interface_arg_list args =
    String.concat "," (List.map (fun (name,opt,typ) -> gen_interface_arg_type_name name opt typ) args)
-   
+
 and cant_be_null haxe_type =
    is_numeric haxe_type || (type_has_meta_key Meta.NotNull haxe_type )
 
diff --git a/src/generators/cpp/cppContext.ml b/src/generators/cpp/cppContext.ml
index 6a45ca0895e..958f26f8467 100644
--- a/src/generators/cpp/cppContext.ml
+++ b/src/generators/cpp/cppContext.ml
@@ -1,8 +1,8 @@
 open Extlib_leftovers
 open Ast
+open Gctx
 open Type
 open Error
-open Common
 open Globals
 open CppAstTools
 
@@ -18,7 +18,7 @@ open CppAstTools
    normal = 1
 *)
 type context = {
-  ctx_common : Common.context;
+  ctx_common : Gctx.t;
   mutable ctx_debug_level : int;
   (* cached as required *)
   mutable ctx_file_info : (string, string) PMap.t ref;
@@ -39,7 +39,7 @@ let new_context common_ctx debug file_info member_types =
   let null_file =
     new CppSourceWriter.source_writer common_ctx ignore ignore (fun () -> ())
   in
-  let has_def def = Common.defined_value_safe common_ctx def <> "" in
+  let has_def def = Gctx.defined_value_safe common_ctx def <> "" in
   let result =
     {
       ctx_common = common_ctx;
@@ -94,8 +94,8 @@ let hash_keys hash =
   !key_list
 
 let is_gc_element ctx member_type =
-  Common.defined ctx.ctx_common Define.HxcppGcGenerational && (is_object_element member_type)
+  Gctx.defined ctx.ctx_common Define.HxcppGcGenerational && (is_object_element member_type)
 
-let strip_file ctx file = match Common.defined ctx Common.Define.AbsolutePath with
+let strip_file ctx file = match Gctx.defined ctx Define.AbsolutePath with
   | true -> Path.get_full_path file
   | false -> ctx.class_paths#relative_path file
\ No newline at end of file
diff --git a/src/generators/cpp/cppExprUtils.ml b/src/generators/cpp/cppExprUtils.ml
index 2bb10e72be6..4ee8a3f2f3e 100644
--- a/src/generators/cpp/cppExprUtils.ml
+++ b/src/generators/cpp/cppExprUtils.ml
@@ -2,7 +2,6 @@ open Extlib_leftovers
 open Ast
 open Type
 open Error
-open Common
 open Globals
 
 let rec remove_parens expression =
diff --git a/src/generators/cpp/cppRetyper.ml b/src/generators/cpp/cppRetyper.ml
index 8aea5442f50..b04927ed9b2 100644
--- a/src/generators/cpp/cppRetyper.ml
+++ b/src/generators/cpp/cppRetyper.ml
@@ -2,7 +2,6 @@ open Extlib_leftovers
 open Ast
 open Type
 open Error
-open Common
 open Globals
 open CppExprUtils
 open CppTypeUtils
@@ -195,7 +194,7 @@ let expression ctx request_type function_args function_type expression_tree forI
   let file_id = ctx.ctx_file_id in
   let function_return_type = ref (cpp_type_of function_type) in
   let loop_stack = ref [] in
-  let forCppia = Common.defined ctx.ctx_common Define.Cppia in
+  let forCppia = Gctx.defined ctx.ctx_common Define.Cppia in
   let alloc_file_id () =
     incr file_id;
     !file_id
diff --git a/src/generators/cpp/cppSourceWriter.ml b/src/generators/cpp/cppSourceWriter.ml
index 477e956c5c9..874d63782a5 100644
--- a/src/generators/cpp/cppSourceWriter.ml
+++ b/src/generators/cpp/cppSourceWriter.ml
@@ -1,8 +1,8 @@
 open Extlib_leftovers
 open Ast
+open Gctx
 open Type
 open Error
-open Common
 open Globals
 open CppStrings
 open CppAstTools
@@ -16,7 +16,7 @@ open CppTypeUtils
 
 let get_include_prefix common_ctx with_slash =
   try
-    Common.defined_value common_ctx Define.IncludePrefix ^ if with_slash then "/" else ""
+    Gctx.defined_value common_ctx Define.IncludePrefix ^ if with_slash then "/" else ""
   with Not_found -> ""
 
 let should_prefix_include = function
@@ -35,10 +35,10 @@ let guarded_include file =
 
 let source_file_extension common_ctx =
   (* no need to -D file_extension if -D objc is defined *)
-  if Common.defined common_ctx Define.Objc then ".mm"
+  if Gctx.defined common_ctx Define.Objc then ".mm"
   else
     try
-      "." ^ Common.defined_value common_ctx Define.FileExtension
+      "." ^ Gctx.defined_value common_ctx Define.FileExtension
     with Not_found -> ".cpp"
 
 class source_writer common_ctx write_header_func write_func close_func =
@@ -166,7 +166,7 @@ let new_source_file common_ctx base_dir sub_dir extension class_path =
   let file =
     cached_source_writer common_ctx (full_dir ^ "/" ^ snd class_path ^ extension)
   in
-  Codegen.map_source_header common_ctx (fun s ->
+  Gctx.map_source_header common_ctx.defines (fun s ->
       file#write_h (Printf.sprintf "// %s\n" s));
   file
 
@@ -179,7 +179,7 @@ let new_header_file common_ctx base_dir =
 let new_placed_cpp_file common_ctx class_path =
   let base_dir = common_ctx.file in
 
-  if (Common.defined common_ctx Define.Vcproj ) then begin
+  if (Gctx.defined common_ctx Define.Vcproj ) then begin
     Path.mkdir_recursive base_dir ("src"::[]);
     cached_source_writer common_ctx
       ( base_dir ^ "/src/" ^ ( String.concat "-" (fst class_path) ) ^ "-" ^
diff --git a/src/generators/cpp/cppStrings.ml b/src/generators/cpp/cppStrings.ml
index 62e5e433b89..99a8d76ef54 100644
--- a/src/generators/cpp/cppStrings.ml
+++ b/src/generators/cpp/cppStrings.ml
@@ -68,7 +68,7 @@ let strq ctx s =
     else "(" ^ split s "" ^ ")"
   in
 
-  if Common.defined ctx Define.HxcppSmartStings && has_utf8_chars s then (
+  if Gctx.defined ctx Define.HxcppSmartStings && has_utf8_chars s then (
     let b = Buffer.create 0 in
 
     let add ichar =
diff --git a/src/generators/cpp/cppTypeUtils.ml b/src/generators/cpp/cppTypeUtils.ml
index ea1c3bff140..d11fcb6712e 100644
--- a/src/generators/cpp/cppTypeUtils.ml
+++ b/src/generators/cpp/cppTypeUtils.ml
@@ -5,7 +5,6 @@ open Extlib_leftovers
 open Ast
 open Type
 open Error
-open Common
 open Globals
 
 let follow = Abstract.follow_with_abstracts
@@ -15,18 +14,18 @@ let is_native_gen_class class_def =
    match class_def.cl_kind with
    | KAbstractImpl abstract_def -> Meta.has Meta.NativeGen abstract_def.a_meta
    | _ -> false
- 
+
 let is_native_gen_module = function
    | TClassDecl class_def -> is_native_gen_class class_def
    | _ -> false
- 
+
 let is_extern_class class_def =
    has_class_flag class_def CExtern ||
    Meta.has Meta.Extern class_def.cl_meta ||
    match class_def.cl_kind with
    | KAbstractImpl abstract_def -> Meta.has Meta.Extern abstract_def.a_meta
    | _ -> false
- 
+
 let is_extern_enum enum_def =
    has_enum_flag enum_def EnExtern || Meta.has Meta.Extern enum_def.e_meta
 
@@ -134,7 +133,7 @@ let is_numeric t =
       -> true
    | _
       -> false
-   
+
 let is_cpp_function_instance t =
    match follow t with
    | TInst ({ cl_path = (["cpp"], "Function") }, _) -> true
diff --git a/src/generators/cpp/gen/cppCppia.ml b/src/generators/cpp/gen/cppCppia.ml
index 2d9259d88d1..08eb43d1108 100644
--- a/src/generators/cpp/gen/cppCppia.ml
+++ b/src/generators/cpp/gen/cppCppia.ml
@@ -2,7 +2,6 @@ open Extlib_leftovers
 open Ast
 open Type
 open Error
-open Common
 open Globals
 open CppExprUtils
 open CppTypeUtils
@@ -499,7 +498,7 @@ class script_writer ctx filename asciiOut =
     val debug = asciiOut
 
     val doComment =
-      asciiOut && Common.defined ctx.ctx_common Define.AnnotateSource
+      asciiOut && Gctx.defined ctx.ctx_common Define.AnnotateSource
 
     val indent_str = if asciiOut then "\t" else ""
     val mutable indent = ""
@@ -511,7 +510,7 @@ class script_writer ctx filename asciiOut =
     val identTable = Hashtbl.create 0
     val fileTable = Hashtbl.create 0
     val identBuffer = Buffer.create 0
-    val cppiaAst = not (Common.defined ctx.ctx_common Define.NoCppiaAst)
+    val cppiaAst = not (Gctx.defined ctx.ctx_common Define.NoCppiaAst)
 
     method stringId name =
       try Hashtbl.find identTable name
@@ -1800,7 +1799,7 @@ let generate_script_class common_ctx script class_def =
               if
                 Meta.has Meta.NativeProperty class_def.cl_meta
                 || Meta.has Meta.NativeProperty field.cf_meta
-                || Common.defined common_ctx Define.ForceNativeProperty
+                || Gctx.defined common_ctx Define.ForceNativeProperty
               then IaAccessCallNative
               else IaAccessCall
           | AccInline -> IaAccessNormal
diff --git a/src/generators/cpp/gen/cppGen.ml b/src/generators/cpp/gen/cppGen.ml
index 2a07db66dde..f5c9061c6cc 100644
--- a/src/generators/cpp/gen/cppGen.ml
+++ b/src/generators/cpp/gen/cppGen.ml
@@ -1,7 +1,7 @@
 open Ast
+open Gctx
 open Type
 open Error
-open Common
 open Globals
 open CppStrings
 open CppExprUtils
@@ -1408,7 +1408,7 @@ let gen_cpp_ast_expression_tree ctx class_name func_name function_args
           out spacer;
           writer#end_block)
     | CppCode (value, exprs) ->
-        Codegen.interpolate_code ctx.ctx_common (format_code value) exprs out
+        Codegen.interpolate_code ctx.ctx_common.error (format_code value) exprs out
           (fun e -> gen e)
           expr.cpppos
     | CppTCast (expr, cppType) -> (
@@ -1752,7 +1752,7 @@ let generate_boot ctx boot_enums boot_classes nonboot_classes init_classes =
     (fun class_path -> boot_file#add_include class_path)
     (boot_enums @ boot_classes @ nonboot_classes);
 
-  let newScriptable = Common.defined common_ctx Define.Scriptable in
+  let newScriptable = Gctx.defined common_ctx Define.Scriptable in
   if newScriptable then (
     output_boot "#include <hx/Scriptable.h>\n";
     let funcs =
@@ -1836,7 +1836,7 @@ let generate_files common_ctx file_info =
       output_files
         (const_char_star
            (Path.get_full_path
-              (try Common.find_file common_ctx file with Not_found -> file))
+              (try Gctx.find_file common_ctx file with Not_found -> file))
         ^ ",\n"))
     (List.sort String.compare (pmap_keys !file_info));
   output_files "#endif\n";
diff --git a/src/generators/cpp/gen/cppGenClassHeader.ml b/src/generators/cpp/gen/cppGenClassHeader.ml
index 8a12ebcc8fc..4a813471de7 100644
--- a/src/generators/cpp/gen/cppGenClassHeader.ml
+++ b/src/generators/cpp/gen/cppGenClassHeader.ml
@@ -1,7 +1,6 @@
 open Ast
 open Type
 open Error
-open Common
 open Globals
 open CppStrings
 open CppExprUtils
@@ -30,7 +29,7 @@ let gen_member_def ctx class_def is_static is_interface field =
           output (gen_args args);
           output (if not is_static then ")=0;\n" else ");\n");
           if reflective class_def field then
-            if Common.defined ctx.ctx_common Define.DynamicInterfaceClosures
+            if Gctx.defined ctx.ctx_common Define.DynamicInterfaceClosures
             then
               output
                 ("\t\tinline ::Dynamic " ^ remap_name
@@ -96,7 +95,7 @@ let gen_member_def ctx class_def is_static is_interface field =
            let return_type = type_to_string function_def.tf_type in
            (if (not is_static) && not nonVirtual then
               let scriptable =
-                Common.defined ctx.ctx_common Define.Scriptable
+                Gctx.defined ctx.ctx_common Define.Scriptable
               in
               if (not (is_internal_member field.cf_name)) && not scriptable then
                 let key =
@@ -202,7 +201,7 @@ let generate baseCtx class_def =
   let nativeGen = Meta.has Meta.NativeGen class_def.cl_meta in
   let smart_class_name = snd class_path in
   let scriptable =
-    Common.defined common_ctx Define.Scriptable && not class_def.cl_private
+    Gctx.defined common_ctx Define.Scriptable && not class_def.cl_private
   in
   let class_name = class_name class_def in
   let ptr_name = class_pointer class_def in
@@ -220,7 +219,7 @@ let generate baseCtx class_def =
   let debug =
     if
       Meta.has Meta.NoDebug class_def.cl_meta
-      || Common.defined baseCtx.ctx_common Define.NoDebug
+      || Gctx.defined baseCtx.ctx_common Define.NoDebug
     then 0
     else 1
   in
@@ -299,7 +298,7 @@ let generate baseCtx class_def =
   output_h "\n\n";
   output_h (get_class_code class_def Meta.HeaderNamespaceCode);
 
-  let extern_class = Common.defined common_ctx Define.DllExport in
+  let extern_class = Gctx.defined common_ctx Define.DllExport in
   let attribs =
     "HXCPP_" ^ (if extern_class then "EXTERN_" else "") ^ "CLASS_ATTRIBUTES"
   in
diff --git a/src/generators/cpp/gen/cppGenClassImplementation.ml b/src/generators/cpp/gen/cppGenClassImplementation.ml
index 009b237f43e..5ee9861bdc4 100644
--- a/src/generators/cpp/gen/cppGenClassImplementation.ml
+++ b/src/generators/cpp/gen/cppGenClassImplementation.ml
@@ -1,7 +1,6 @@
 open Ast
 open Type
 open Error
-open Common
 open Globals
 open CppStrings
 open CppExprUtils
@@ -301,7 +300,7 @@ let generate baseCtx class_def =
   let output_cpp = cpp_file#write in
   let strq = strq ctx.ctx_common in
   let scriptable =
-    Common.defined common_ctx Define.Scriptable && not class_def.cl_private
+    Gctx.defined common_ctx Define.Scriptable && not class_def.cl_private
   in
 
   let class_super_name =
@@ -690,7 +689,7 @@ let generate baseCtx class_def =
       if
         Meta.has Meta.NativeProperty class_def.cl_meta
         || Meta.has Meta.NativeProperty field.cf_meta
-        || Common.defined common_ctx Define.ForceNativeProperty
+        || Gctx.defined common_ctx Define.ForceNativeProperty
       then "inCallProp != ::hx::paccNever"
       else "inCallProp == ::hx::paccAlways"
     in
@@ -1114,7 +1113,7 @@ let generate baseCtx class_def =
         if return_type <> "void" then output_cpp "return null();";
         output_cpp "}\n";
         let dynamic_interface_closures =
-          Common.defined baseCtx.ctx_common Define.DynamicInterfaceClosures
+          Gctx.defined baseCtx.ctx_common Define.DynamicInterfaceClosures
         in
         if has_class_flag class_def CInterface && not dynamic_interface_closures
         then
diff --git a/src/generators/cpp/gen/cppGenEnum.ml b/src/generators/cpp/gen/cppGenEnum.ml
index 287ab5d5558..ae00e32708f 100644
--- a/src/generators/cpp/gen/cppGenEnum.ml
+++ b/src/generators/cpp/gen/cppGenEnum.ml
@@ -1,7 +1,6 @@
 open Ast
 open Type
 open Error
-open Common
 open Globals
 open CppStrings
 open CppExprUtils
@@ -20,7 +19,7 @@ let generate baseCtx enum_def =
   let remap_class_name = ("::" ^ (join_class_path_remap class_path "::") )  in
   let cpp_file         = new_placed_cpp_file common_ctx class_path in
   let output_cpp       = (cpp_file#write) in
-  let debug            = if (Meta.has Meta.NoDebug enum_def.e_meta) || ( Common.defined common_ctx Define.NoDebug) then 0 else 1 in
+  let debug            = if (Meta.has Meta.NoDebug enum_def.e_meta) || ( Gctx.defined common_ctx Define.NoDebug) then 0 else 1 in
 
   let ctx = file_context baseCtx cpp_file debug false in
   let strq = strq ctx.ctx_common in
@@ -209,4 +208,4 @@ let generate baseCtx enum_def =
   end_namespace output_h class_path;
 
   end_header_file output_h def_string;
-  h_file#close 
+  h_file#close
diff --git a/src/generators/cpp/gen/cppReferences.ml b/src/generators/cpp/gen/cppReferences.ml
index 703b9458f60..15e39fe5989 100644
--- a/src/generators/cpp/gen/cppReferences.ml
+++ b/src/generators/cpp/gen/cppReferences.ml
@@ -1,7 +1,6 @@
 open Ast
 open Type
 open Error
-open Common
 open Globals
 open CppStrings
 open CppExprUtils
diff --git a/src/generators/gctx.ml b/src/generators/gctx.ml
new file mode 100644
index 00000000000..2785bcf1cef
--- /dev/null
+++ b/src/generators/gctx.ml
@@ -0,0 +1,119 @@
+open Globals
+open Type
+open Warning
+
+type context_main = {
+	mutable main_class : path option;
+	mutable main_expr : texpr option;
+}
+
+type warning_function = ?depth:int -> ?from_macro:bool -> warning -> Warning.warning_option list list -> string -> pos -> unit
+type error_function = ?depth:int -> string -> pos -> unit
+
+type t = {
+	platform : platform;
+	defines : Define.define;
+	class_paths : ClassPaths.class_paths;
+	run_command : string -> int;
+	run_command_args : string -> string list -> int;
+	warning : warning_function;
+	error : error_function;
+	print : string -> unit;
+	basic : basic_types;
+	debug : bool;
+	file : string;
+	version : int;
+	features : (string,bool) Hashtbl.t;
+	modules : Type.module_def list;
+	main : context_main;
+	types : Type.module_type list;
+	resources : (string,string) Hashtbl.t;
+	native_libs : NativeLibraries.native_library_base list;
+	include_files : (string * string) list;
+	std : tclass; (* TODO: I would prefer to not have this here, have to check default_cast *)
+}
+
+let defined com s =
+	Define.defined com.defines s
+
+let defined_value com v =
+	Define.defined_value com.defines v
+
+let define_value com k v =
+	Define.define_value com.defines k v
+
+let defined_value_safe ?default com v =
+	match default with
+		| Some s -> Define.defined_value_safe ~default:s com.defines v
+		| None -> Define.defined_value_safe com.defines v
+
+let raw_defined gctx v =
+	Define.raw_defined gctx.defines v
+
+let find_file ctx f =
+	(ctx.class_paths#find_file f).file
+
+let add_feature gctx f =
+	Hashtbl.replace gctx.features f true
+
+let has_dce gctx =
+	try
+		Define.defined_value gctx.defines Define.Dce <> "no"
+with Not_found ->
+	false
+
+let is_directly_used gctx meta =
+	not (has_dce gctx) || Meta.has Meta.DirectlyUsed meta
+
+let rec has_feature gctx f =
+	try
+		Hashtbl.find gctx.features f
+	with Not_found ->
+		if gctx.types = [] then not (has_dce gctx) else
+		match List.rev (ExtString.String.nsplit f ".") with
+		| [] -> die "" __LOC__
+		| [cl] -> has_feature gctx (cl ^ ".*")
+		| field :: cl :: pack ->
+			let r = (try
+				let path = List.rev pack, cl in
+				(match List.find (fun t -> t_path t = path && not (Meta.has Meta.RealPath (t_infos t).mt_meta)) gctx.types with
+				| t when field = "*" ->
+					not (has_dce gctx) ||
+					begin match t with
+						| TClassDecl c ->
+							has_class_flag c CUsed;
+						| TAbstractDecl a ->
+							Meta.has Meta.ValueUsed a.a_meta
+						| _ -> Meta.has Meta.Used (t_infos t).mt_meta
+					end;
+				| TClassDecl c when (has_class_flag c CExtern) && (gctx.platform <> Js || cl <> "Array" && cl <> "Math") ->
+					not (has_dce gctx) || has_class_field_flag (try PMap.find field c.cl_statics with Not_found -> PMap.find field c.cl_fields) CfUsed
+				| TClassDecl c ->
+					PMap.exists field c.cl_statics || PMap.exists field c.cl_fields
+				| _ ->
+					false)
+			with Not_found ->
+				false
+			) in
+			Hashtbl.add gctx.features f r;
+			r
+
+let get_entry_point gctx =
+	Option.map (fun path ->
+		let m = List.find (fun m -> m.m_path = path) gctx.modules in
+		let c =
+			match m.m_statics with
+			| Some c when (PMap.mem "main" c.cl_statics) -> c
+			| _ -> Option.get (ExtList.List.find_map (fun t -> match t with TClassDecl c when c.cl_path = path -> Some c | _ -> None) m.m_types)
+		in
+		let e = Option.get gctx.main.main_expr in (* must be present at this point *)
+		(snd path, c, e)
+	) gctx.main.main_class
+
+let get_es_version defines =
+	try int_of_string (Define.defined_value defines Define.JsEs) with _ -> 0
+
+let map_source_header defines f =
+	match Define.defined_value_safe defines Define.SourceHeader with
+	| "" -> ()
+	| s -> f s
\ No newline at end of file
diff --git a/src/generators/gencpp.ml b/src/generators/gencpp.ml
index 3c06e600b17..1999ca983bc 100644
--- a/src/generators/gencpp.ml
+++ b/src/generators/gencpp.ml
@@ -17,9 +17,9 @@
    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  *)
 open Ast
+open Gctx
 open Type
 open Error
-open Common
 open Globals
 open CppStrings
 open CppExprUtils
@@ -127,7 +127,7 @@ let write_build_data common_ctx filename classes main_deps boot_deps build_extra
    in
 
    output_string buildfile "<xml>\n";
-   let api_string = (Common.defined_value common_ctx Define.HxcppApiLevel) in
+   let api_string = (Gctx.defined_value common_ctx Define.HxcppApiLevel) in
    output_string buildfile ("<set name=\"HXCPP_API_LEVEL\" value=\"" ^ api_string ^ "\" />\n");
    output_string buildfile "<files id=\"haxe\">\n";
    output_string buildfile "<compilerflag value=\"-Iinclude\"/>\n";
@@ -160,7 +160,7 @@ let write_build_data common_ctx filename classes main_deps boot_deps build_extra
    output_string buildfile ("<set name=\"HAXE_OUTPUT\" value=\"" ^ exe_name ^ "\" />\n");
    output_string buildfile "<include name=\"${HXCPP}/build-tool/BuildCommon.xml\"/>\n";
    output_string buildfile build_extra;
-   if (Common.defined common_ctx Define.HxcppSmartStings) then
+   if (Gctx.defined common_ctx Define.HxcppSmartStings) then
       output_string buildfile ("<error value=\"Hxcpp is out of date - please update\" unlessApi=\"" ^ api_string ^ "\" />\n");
    output_string buildfile "</xml>\n";
    close_out buildfile
@@ -225,13 +225,13 @@ let generate_source ctx =
    let extern_src = ref [] in
    let jobs = ref [] in
    let build_xml = ref "" in
-   let scriptable = (Common.defined common_ctx Define.Scriptable) in
+   let scriptable = (Gctx.defined common_ctx Define.Scriptable) in
    let existingIds = Hashtbl.create 0 in
 
    List.iter (fun object_def ->
       (* check if any @:objc class is referenced while '-D objc' is not defined
          This will guard all code changes to this flag *)
-      (if not (Common.defined common_ctx Define.Objc) then match object_def with
+      (if not (Gctx.defined common_ctx Define.Objc) then match object_def with
          | TClassDecl class_def when Meta.has Meta.Objc class_def.cl_meta ->
             abort "In order to compile '@:objc' classes, please define '-D objc'" class_def.cl_pos
          | _ -> ());
@@ -320,10 +320,10 @@ let generate_source ctx =
    write_resources common_ctx;
 
    (* Output class info if requested *)
-   if (scriptable || (Common.defined common_ctx Define.DllExport) ) then begin
+   if (scriptable || (Gctx.defined common_ctx Define.DllExport) ) then begin
       let filename =
          try
-            let value = Common.defined_value common_ctx Define.DllExport in
+            let value = Gctx.defined_value common_ctx Define.DllExport in
             if value="1" then raise Not_found;
             value
          with Not_found -> "export_classes.info"
@@ -357,7 +357,7 @@ let generate_source ctx =
 
          (* Output file info too *)
          List.iter ( fun file ->
-               let full_path = Path.get_full_path (try Common.find_file common_ctx file with Not_found -> file) in
+               let full_path = Path.get_full_path (try Gctx.find_file common_ctx file with Not_found -> file) in
                if file <> "?" then
                   out ("file " ^ (escape file) ^ " " ^ (escape full_path) ^"\n") )
             ( List.sort String.compare ( pmap_keys !(ctx.ctx_file_info) ) );
@@ -371,7 +371,7 @@ let generate_source ctx =
 
    write_build_data common_ctx (common_ctx.file ^ "/Build.xml") !exe_classes !main_deps (!boot_enums@ !boot_classes) !build_xml !extern_src output_name;
    write_build_options common_ctx (common_ctx.file ^ "/Options.txt") common_ctx.defines.Define.values;
-   if ( not (Common.defined common_ctx Define.NoCompilation) ) then begin
+   if ( not (Gctx.defined common_ctx Define.NoCompilation) ) then begin
       let t = Timer.timer ["generate";"cpp";"native compilation"] in
       let old_dir = Sys.getcwd() in
       Sys.chdir common_ctx.file;
@@ -392,8 +392,8 @@ let generate_source ctx =
    end
 
 let generate common_ctx =
-   let debug_level = if (Common.defined common_ctx Define.NoDebug) then 0 else 1 in
-   if (Common.defined common_ctx Define.Cppia) then begin
+   let debug_level = if (Gctx.defined common_ctx Define.NoDebug) then 0 else 1 in
+   if (Gctx.defined common_ctx Define.Cppia) then begin
       let ctx = new_context common_ctx debug_level (ref PMap.empty) (Hashtbl.create 0)  in
       CppCppia.generate_cppia ctx
    end else begin
diff --git a/src/generators/genhl.ml b/src/generators/genhl.ml
index 06b29a4d7d0..2558b7c2f29 100644
--- a/src/generators/genhl.ml
+++ b/src/generators/genhl.ml
@@ -24,7 +24,7 @@ open Globals
 open Ast
 open Type
 open Error
-open Common
+open Gctx
 open Hlcode
 
 (* compiler *)
@@ -85,7 +85,7 @@ type constval =
 	| CString of string
 
 type context = {
-	com : Common.context;
+	com : Gctx.t;
 	cglobals : (string, ttype) lookup;
 	cstrings : (string, string) lookup;
 	cbytes : (bytes, bytes) lookup;
@@ -325,7 +325,7 @@ let set_curpos ctx p =
 
 let make_debug ctx arr =
 	let get_relative_path p =
-		match Common.defined ctx.com Common.Define.AbsolutePath with
+		match Gctx.defined ctx.com Define.AbsolutePath with
 		| true -> if (Filename.is_relative p.pfile)
 			then Filename.concat (Sys.getcwd()) p.pfile
 			else p.pfile
@@ -3463,7 +3463,7 @@ let generate_static ctx c f =
 			| (Meta.HlNative,[(EConst(String(lib,_)),_)] ,_ ) :: _ ->
 				add_native lib f.cf_name
 			| (Meta.HlNative,[(EConst(Float(ver,_)),_)] ,_ ) :: _ ->
-				let cur_ver = (try Common.defined_value ctx.com Define.HlVer with Not_found -> "") in
+				let cur_ver = (try Gctx.defined_value ctx.com Define.HlVer with Not_found -> "") in
 				if cur_ver < ver then
 					let gen_content() =
 						op ctx (OThrow (make_string ctx ("Requires compiling with -D hl-ver=" ^ ver ^ ".0 or higher") null_pos));
@@ -4126,8 +4126,8 @@ let create_context com dump =
 	in
 	let ctx = {
 		com = com;
-		optimize = not (Common.raw_defined com "hl_no_opt");
-		w_null_compare = Common.raw_defined com "hl_w_null_compare";
+		optimize = not (Gctx.raw_defined com "hl_no_opt");
+		w_null_compare = Gctx.raw_defined com "hl_w_null_compare";
 		dump_out = if dump then Some (IO.output_channel (open_out_bin "dump/hlopt.txt")) else None;
 		m = method_context 0 HVoid null_capture false;
 		cints = new_lookup();
@@ -4247,8 +4247,8 @@ let make_context_sign com =
 let prev_sign = ref "" and prev_data = ref ""
 
 let generate com =
-	let dump = Common.defined com Define.Dump in
-	let hl_check = Common.raw_defined com "hl_check" in
+	let dump = Gctx.defined com Define.Dump in
+	let hl_check = Gctx.raw_defined com "hl_check" in
 
 	let sign = make_context_sign com in
 	if sign = !prev_sign && not dump && not hl_check then begin
@@ -4268,7 +4268,7 @@ let generate com =
 		Hlcode.dump (fun s -> output_string ch (s ^ "\n")) code;
 		close_out ch;
 	end;
-	(*if Common.raw_defined com "hl_dump_spec" then begin
+	(*if Gctx.raw_defined com "hl_dump_spec" then begin
 		let ch = open_out_bin "dump/hlspec.txt" in
 		let write s = output_string ch (s ^ "\n") in
 		Array.iter (fun f ->
@@ -4294,19 +4294,19 @@ let generate com =
 	if Path.file_extension com.file = "c" then begin
 		let gnames = Array.make (Array.length code.globals) "" in
 		PMap.iter (fun n i -> gnames.(i) <- n) ctx.cglobals.map;
-		if not (Common.defined com Define.SourceHeader) then begin
+		if not (Gctx.defined com Define.SourceHeader) then begin
 			let version_major = com.version / 1000 in
 			let version_minor = (com.version mod 1000) / 100 in
 			let version_revision = (com.version mod 100) in
-			Common.define_value com Define.SourceHeader (Printf.sprintf "Generated by HLC %d.%d.%d (HL v%d)" version_major version_minor version_revision code.version);
+			Gctx.define_value com Define.SourceHeader (Printf.sprintf "Generated by HLC %d.%d.%d (HL v%d)" version_major version_minor version_revision code.version);
 		end;
 		Hl2c.write_c com com.file code gnames;
 		let t = Timer.timer ["nativecompile";"hl"] in
-		if not (Common.defined com Define.NoCompilation) && com.run_command_args "haxelib" ["run";"hashlink";"build";escape_command com.file] <> 0 then failwith "Build failed";
+		if not (Gctx.defined com Define.NoCompilation) && com.run_command_args "haxelib" ["run";"hashlink";"build";escape_command com.file] <> 0 then failwith "Build failed";
 		t();
 	end else begin
 		let ch = IO.output_string() in
-		write_code ch code (not (Common.raw_defined com "hl_no_debug"));
+		write_code ch code (not (Gctx.raw_defined com "hl_no_debug"));
 		let str = IO.close_out ch in
 		let ch = open_out_bin com.file in
 		output_string ch str;
@@ -4316,10 +4316,10 @@ let generate com =
 	end;
 	Hlopt.clean_cache();
 	t();
-	if Common.raw_defined com "run" then begin
+	if Gctx.raw_defined com "run" then begin
 		if com.run_command_args "haxelib" ["run";"hashlink";"run";escape_command com.file] <> 0 then failwith "Failed to run HL";
 	end;
-	if Common.defined com Define.Interp then
+	if Gctx.defined com Define.Interp then
 		try
 			let t = Timer.timer ["generate";"hl";"interp"] in
 			let ctx = Hlinterp.create true in
diff --git a/src/generators/genjs.ml b/src/generators/genjs.ml
index 2a60f6f8093..ce8c98dbd0a 100644
--- a/src/generators/genjs.ml
+++ b/src/generators/genjs.ml
@@ -21,11 +21,11 @@ open Globals
 open Ast
 open Type
 open Error
-open Common
+open Gctx
 open JsSourcemap
 
 type ctx = {
-	com : Common.context;
+	com : Gctx.t;
 	buf : Rbuffer.t;
 	mutable chan : out_channel option;
 	packages : (string list,unit) Hashtbl.t;
@@ -46,7 +46,6 @@ type ctx = {
 	mutable separator : bool;
 	mutable found_expose : bool;
 	mutable catch_vars : texpr list;
-	mutable deprecation_context : DeprecationCheck.deprecation_context;
 }
 
 type object_store = {
@@ -90,7 +89,7 @@ let es5kwds = [
 
 let setup_kwds com =
 	Hashtbl.reset kwds;
-	let es_version = get_es_version com in
+	let es_version = Gctx.get_es_version com.defines in
 	let lst = if es_version >= 5 then es5kwds else es3kwds in
 	List.iter (fun s -> Hashtbl.add kwds s ()) lst
 
@@ -148,8 +147,8 @@ let module_field_expose_path mpath f =
 	with Not_found ->
 		(dot_path mpath) ^ "." ^ f.cf_name
 
-let has_feature ctx = Common.has_feature ctx.com
-let add_feature ctx = Common.add_feature ctx.com
+let has_feature ctx = Gctx.has_feature ctx.com
+let add_feature ctx = Gctx.add_feature ctx.com
 
 let unsupported p = abort "This expression cannot be compiled to Javascript" p
 
@@ -367,24 +366,6 @@ let rec gen_call ctx e el in_value =
 			| _ ->
 				abort "js.Lib.getOriginalException can only be called inside a catch block" e.epos
 		)
-	| TIdent "__new__", args ->
-		print_deprecation_message ctx.deprecation_context "__new__ is deprecated, use js.Syntax.construct instead" e.epos;
-		gen_syntax ctx "construct" args e.epos
-	| TIdent "__js__", args ->
-		print_deprecation_message ctx.deprecation_context "__js__ is deprecated, use js.Syntax.code instead" e.epos;
-		gen_syntax ctx "code" args e.epos
-	| TIdent "__instanceof__",  args ->
-		print_deprecation_message ctx.deprecation_context "__instanceof__ is deprecated, use js.Syntax.instanceof instead" e.epos;
-		gen_syntax ctx "instanceof" args e.epos
-	| TIdent "__typeof__",  args ->
-		print_deprecation_message ctx.deprecation_context "__typeof__ is deprecated, use js.Syntax.typeof instead" e.epos;
-		gen_syntax ctx "typeof" args e.epos
-	| TIdent "__strict_eq__" , args ->
-		print_deprecation_message ctx.deprecation_context "__strict_eq__ is deprecated, use js.Syntax.strictEq instead" e.epos;
-		gen_syntax ctx "strictEq" args e.epos
-	| TIdent "__strict_neq__" , args ->
-		print_deprecation_message ctx.deprecation_context "__strict_neq__ is deprecated, use js.Syntax.strictNeq instead" e.epos;
-		gen_syntax ctx "strictNeq" args e.epos
 	| TIdent "__define_feature__", [_;e] ->
 		gen_expr ctx e
 	| TIdent "__feature__", { eexpr = TConst (TString f) } :: eif :: eelse ->
@@ -550,13 +531,13 @@ and gen_expr ctx e =
 			print ctx ",$bind($_,$_%s))" (if Meta.has Meta.SelfCall f.cf_meta then "" else (field f.cf_name)))
 	| TEnumIndex x ->
 		gen_value ctx x;
-		if not (Common.defined ctx.com Define.JsEnumsAsArrays) then
+		if not (Gctx.defined ctx.com Define.JsEnumsAsArrays) then
 		print ctx "._hx_index"
 		else
 		print ctx "[1]"
 	| TEnumParameter (x,f,i) ->
 		gen_value ctx x;
-		if not (Common.defined ctx.com Define.JsEnumsAsArrays) then
+		if not (Gctx.defined ctx.com Define.JsEnumsAsArrays) then
 			let fname = (match f.ef_type with TFun((args,_)) -> let fname,_,_ = List.nth args i in  fname | _ -> die "" __LOC__ ) in
 			print ctx ".%s" (ident fname)
 		else
@@ -1031,7 +1012,7 @@ and gen_syntax ctx meth args pos =
 					)
 					args
 				in
-				Codegen.interpolate_code ctx.com code args (spr ctx) (gen_value ctx) code_pos
+				Codegen.interpolate_code ctx.com.error code args (spr ctx) (gen_value ctx) code_pos
 		end
 	| "plainCode", [code] ->
 		let code =
@@ -1147,7 +1128,6 @@ let can_gen_class_field ctx = function
 		is_physical_field f
 
 let gen_class_field ctx c f =
-	ctx.deprecation_context <- {ctx.deprecation_context with field_meta = f.cf_meta};
 	check_field_name c f;
 	match f.cf_expr with
 	| None ->
@@ -1473,7 +1453,6 @@ let generate_class_es6 ctx c =
 
 let generate_class ctx c =
 	ctx.current <- c;
-	ctx.deprecation_context <- {ctx.deprecation_context with class_meta = c.cl_meta};
 	ctx.id_counter <- 0;
 	(match c.cl_path with
 	| [],"Function" -> abort "This class redefine a native one" c.cl_pos
@@ -1496,7 +1475,7 @@ let generate_enum ctx e =
 	else
 		generate_package_create ctx e.e_path;
 	print ctx "%s = " p;
-	let as_objects = not (Common.defined ctx.com Define.JsEnumsAsArrays) in
+	let as_objects = not (Gctx.defined ctx.com Define.JsEnumsAsArrays) in
 	(if as_objects then
 		print ctx "$hxEnums[\"%s\"] = " dotp
 	else if has_feature ctx "Type.resolveEnum" then
@@ -1653,7 +1632,7 @@ let set_current_class ctx c =
 
 let alloc_ctx com es_version =
 	let smap =
-		if com.debug || Common.defined com Define.JsSourceMap || Common.defined com Define.SourceMap then
+		if com.debug || Gctx.defined com Define.JsSourceMap || Gctx.defined com Define.SourceMap then
 			Some {
 				source_last_pos = { file = 0; line = 0; col = 0};
 				print_comma = false;
@@ -1673,10 +1652,10 @@ let alloc_ctx com es_version =
 		chan = None;
 		packages = Hashtbl.create 0;
 		smap = smap;
-		js_modern = not (Common.defined com Define.JsClassic);
-		js_flatten = not (Common.defined com Define.JsUnflatten);
-		has_resolveClass = Common.has_feature com "Type.resolveClass";
-		has_interface_check = Common.has_feature com "js.Boot.__interfLoop";
+		js_modern = not (Gctx.defined com Define.JsClassic);
+		js_flatten = not (Gctx.defined com Define.JsUnflatten);
+		has_resolveClass = Gctx.has_feature com "Type.resolveClass";
+		has_interface_check = Gctx.has_feature com "js.Boot.__interfLoop";
 		es_version = es_version;
 		statics = [];
 		inits = [];
@@ -1689,7 +1668,6 @@ let alloc_ctx com es_version =
 		separator = false;
 		found_expose = false;
 		catch_vars = [];
-		deprecation_context = DeprecationCheck.create_context com;
 	} in
 
 	ctx.type_accessor <- (fun t ->
@@ -1714,22 +1692,22 @@ let gen_single_expr ctx e expr =
 	ctx.id_counter <- 0;
 	str
 
-let generate com =
-	(match com.js_gen with
+let generate js_gen com =
+	(match js_gen with
 	| Some g -> g()
 	| None ->
 
-	let es_version = get_es_version com in
+	let es_version = Gctx.get_es_version com.defines in
 
 	if es_version >= 6 then
 		ES6Ctors.rewrite_ctors com;
 
 	let ctx = alloc_ctx com es_version in
-	Codegen.map_source_header com (fun s -> print ctx "// %s\n" s);
+	Gctx.map_source_header com.defines (fun s -> print ctx "// %s\n" s);
 	if has_feature ctx "Class" || has_feature ctx "Type.getClassName" then add_feature ctx "js.Boot.isClass";
 	if has_feature ctx "Enum" || has_feature ctx "Type.getEnumName" then add_feature ctx "js.Boot.isEnum";
 
-	let nodejs = Common.raw_defined com "nodejs" in
+	let nodejs = Gctx.raw_defined com "nodejs" in
 
 	setup_kwds com;
 
@@ -1792,7 +1770,7 @@ let generate com =
 		| _ -> ()
 	) include_files;
 
-	let defined_global_value = Common.defined_value_safe com Define.JsGlobal in
+	let defined_global_value = Gctx.defined_value_safe com Define.JsGlobal in
 
 	let defined_global = defined_global_value <> "" in
 
@@ -1813,7 +1791,7 @@ let generate com =
 	) in
 
 	let closureArgs = [var_global] in
-	let closureArgs = if (anyExposed && not (Common.defined com Define.ShallowExpose)) then
+	let closureArgs = if (anyExposed && not (Gctx.defined com Define.ShallowExpose)) then
 		var_exports :: closureArgs
 	else
 		closureArgs
@@ -1829,7 +1807,7 @@ let generate com =
 		(* Add node globals to pseudo-keywords, so they are not shadowed by local vars *)
 		List.iter (fun s -> Hashtbl.replace kwds2 s ()) [ "global"; "process"; "__filename"; "__dirname"; "module" ];
 
-	if (anyExposed && ((Common.defined com Define.ShallowExpose) || not ctx.js_modern)) then (
+	if (anyExposed && ((Gctx.defined com Define.ShallowExpose) || not ctx.js_modern)) then (
 		print ctx "var %s = %s" (fst var_exports) (snd var_exports);
 		ctx.separator <- true;
 		newline ctx
@@ -1870,7 +1848,7 @@ let generate com =
 	if (not ctx.js_modern) && (ctx.es_version < 5) then
 		spr ctx "var console = $global.console || {log:function(){}};\n";
 
-	let enums_as_objects = not (Common.defined com Define.JsEnumsAsArrays) in
+	let enums_as_objects = not (Gctx.defined com Define.JsEnumsAsArrays) in
 
 	(* TODO: fix $estr *)
 	let vars = [] in
@@ -1989,7 +1967,7 @@ let generate com =
 		newline ctx;
 	end;
 
-	if (anyExposed && (Common.defined com Define.ShallowExpose)) then (
+	if (anyExposed && (Gctx.defined com Define.ShallowExpose)) then (
 		List.iter (fun f ->
 			print ctx "var %s = $hx_exports%s" f.os_name (path_to_brackets f.os_name);
 			ctx.separator <- true;
@@ -2006,7 +1984,7 @@ let generate com =
 	| Some smap ->
 		write_mappings ctx.com smap "file:///";
 		let basefile = Filename.basename com.file in
-		print ctx "\n//# sourceMappingURL=%s.map" (url_encode_s basefile);
+		print ctx "\n//# sourceMappingURL=%s.map" (StringHelper.url_encode_s basefile);
 	| None -> try Sys.remove (com.file ^ ".map") with _ -> ());
 	flush ctx;
 	Option.may (fun chan -> close_out chan) ctx.chan
diff --git a/src/generators/genjvm.ml b/src/generators/genjvm.ml
index 979d512c688..ad6033244ba 100644
--- a/src/generators/genjvm.ml
+++ b/src/generators/genjvm.ml
@@ -19,7 +19,7 @@
 
 open Globals
 open Ast
-open Common
+open Gctx
 open Type
 open Path
 open JvmGlobals
@@ -53,7 +53,7 @@ let get_construction_mode c cf =
 (* Haxe *)
 
 type generation_context = {
-	com : Common.context;
+	gctx : Gctx.t;
 	out : Zip_output.any_output;
 	t_runtime_exception : Type.t;
 	entry_point : (tclass * texpr) option;
@@ -515,7 +515,6 @@ class texpr_to_jvm
 	(jm : JvmMethod.builder)
 	(return_type : jsignature option)
 = object(self)
-	val com = gctx.com
 	val code = jm#get_code
 	val pool : JvmConstantPool.constant_pool = jc#get_pool
 
@@ -531,7 +530,7 @@ class texpr_to_jvm
 	method vtype t =
 		jsignature_of_type gctx t
 
-	method mknull t = com.basic.tnull (follow t)
+	method mknull t = gctx.gctx.basic.tnull (follow t)
 
 	(* locals *)
 
@@ -1000,13 +999,13 @@ class texpr_to_jvm
 			store();
 			let ev = mk (TLocal v) v.v_type null_pos in
 			let el = List.rev_map (fun case ->
-				let f e' = mk (TBinop(OpEq,ev,e')) com.basic.tbool e'.epos in
+				let f e' = mk (TBinop(OpEq,ev,e')) gctx.gctx.basic.tbool e'.epos in
 				let e_cond = match case.case_patterns with
 					| [] -> die "" __LOC__
 					| [e] -> f e
 					| e :: el ->
 						List.fold_left (fun eacc e ->
-							mk (TBinop(OpBoolOr,eacc,f e)) com.basic.tbool e.epos
+							mk (TBinop(OpBoolOr,eacc,f e)) gctx.gctx.basic.tbool e.epos
 						) (f e) el
 				in
 				(e_cond,case.case_expr)
@@ -2143,7 +2142,7 @@ class texpr_to_jvm
 		| TParenthesis e1 | TMeta(_,e1) ->
 			self#texpr ret e1
 		| TFor(v,e1,e2) ->
-			self#texpr ret (Texpr.for_remap com.basic v e1 e2 e.epos)
+			self#texpr ret (Texpr.for_remap gctx.gctx.basic v e1 e2 e.epos)
 		| TEnumIndex e1 ->
 			self#texpr rvalue_any e1;
 			jm#invokevirtual java_enum_path "ordinal" (method_sig [] (Some TInt))
@@ -2593,9 +2592,9 @@ class tclass_to_jvm gctx c = object(self)
 			| None ->
 				if c.cl_path = (["haxe"],"Resource") && cf.cf_name = "content" then begin
 					let el = Hashtbl.fold (fun name _ acc ->
-						Texpr.Builder.make_string gctx.com.basic name null_pos :: acc
-					) gctx.com.resources [] in
-					let e = mk (TArrayDecl el) (gctx.com.basic.tarray gctx.com.basic.tstring) null_pos in
+						Texpr.Builder.make_string gctx.gctx.basic name null_pos :: acc
+					) gctx.gctx.resources [] in
+					let e = mk (TArrayDecl el) (gctx.gctx.basic.tarray gctx.gctx.basic.tstring) null_pos in
 					default e;
 				end;
 			| Some e when mtype <> MStatic ->
@@ -2606,8 +2605,8 @@ class tclass_to_jvm gctx c = object(self)
 				begin match cf.cf_kind with
 					| Method MethDynamic ->
 						let enull = Texpr.Builder.make_null efield.etype null_pos in
-						let echeck = Texpr.Builder.binop OpEq efield enull gctx.com.basic.tbool null_pos in
-						let eif = mk (TIf(echeck,eop,None)) gctx.com.basic.tvoid null_pos in
+						let echeck = Texpr.Builder.binop OpEq efield enull gctx.gctx.basic.tbool null_pos in
+						let eif = mk (TIf(echeck,eop,None)) gctx.gctx.basic.tvoid null_pos in
 						DynArray.add delayed_field_inits eif
 					| _ ->
 						DynArray.add field_inits eop
@@ -2644,7 +2643,7 @@ class tclass_to_jvm gctx c = object(self)
 		let jsig = method_sig [array_sig string_sig] None in
 		let jm = jc#spawn_method "main" jsig [MPublic;MStatic] in
 		let _,load,_ = jm#add_local "args" (TArray(string_sig,None)) VarArgument in
-		if has_feature gctx.com "haxe.root.Sys.args" then begin
+		if has_feature gctx.gctx "haxe.root.Sys.args" then begin
 			load();
 			jm#putstatic (["haxe";"root"],"Sys") "_args" (TArray(string_sig,None))
 		end;
@@ -2874,7 +2873,7 @@ let generate_enum gctx en =
 		jm_values#new_native_array (object_path_sig jc_enum#get_this_path) fl;
 		jm_values#return;
 		(* Add __meta__ TODO: do this via annotations instead? *)
-		begin match Texpr.build_metadata gctx.com.basic (TEnumDecl en) with
+		begin match Texpr.build_metadata gctx.gctx.basic (TEnumDecl en) with
 		| None ->
 			()
 		| Some e ->
@@ -3037,7 +3036,7 @@ module Preprocessor = struct
 				| _ ->
 					()
 			) m.m_types
-		) gctx.com.modules;
+		) gctx.gctx.modules;
 		(* preprocess classes *)
 		List.iter (fun mt ->
 			match mt with
@@ -3047,24 +3046,24 @@ module Preprocessor = struct
 				else if has_class_flag c CFunctionalInterface then
 					check_functional_interface gctx c
 			| _ -> ()
-		) gctx.com.types;
+		) gctx.gctx.types;
 		(* find typedef-interface implementations *)
 		List.iter (fun mt -> match mt with
 			| TClassDecl c when not (has_class_flag c CInterface) && not (has_class_flag c CExtern) ->
 				gctx.typedef_interfaces#process_class c;
 			| _ ->
 				()
-		) gctx.com.types
+		) gctx.gctx.types
 end
 
-let generate jvm_flag com =
-	let path = FilePath.parse com.file in
-	let jar_name,entry_point = match get_entry_point com with
+let generate jvm_flag gctx =
+	let path = FilePath.parse gctx.file in
+	let jar_name,entry_point = match get_entry_point gctx with
 		| Some (jarname,cl,expr) -> jarname, Some (cl,expr)
 		| None -> "jar",None
 	in
 	let compression_level = try
-		int_of_string (Define.defined_value com.defines Define.JvmCompressionLevel)
+		int_of_string (Define.defined_value gctx.defines Define.JvmCompressionLevel)
 	with _ ->
 		6
 	in
@@ -3077,10 +3076,10 @@ let generate jvm_flag com =
 		| Some _ ->
 			begin match path.directory with
 				| None ->
-					"./",create_jar ("./" ^ com.file)
+					"./",create_jar ("./" ^ gctx.file)
 				| Some dir ->
 					mkdir_from_path dir;
-					add_trailing_slash dir,create_jar com.file
+					add_trailing_slash dir,create_jar gctx.file
 			end
 		| None -> match path.directory with
 			| Some dir ->
@@ -3089,25 +3088,25 @@ let generate jvm_flag com =
 			| None ->
 				failwith "Please specify an output file name"
 	end else begin
-		let jar_name = if com.debug then jar_name ^ "-Debug" else jar_name in
-		let jar_dir = add_trailing_slash com.file in
+		let jar_name = if gctx.debug then jar_name ^ "-Debug" else jar_name in
+		let jar_dir = add_trailing_slash gctx.file in
 		let jar_path = Printf.sprintf "%s%s.jar" jar_dir jar_name in
 		jar_dir,create_jar jar_path
 	end in
 	let anon_identification = new tanon_identification in
 	let dynamic_level = try
-		int_of_string (Define.defined_value com.defines Define.JvmDynamicLevel)
+		int_of_string (Define.defined_value gctx.defines Define.JvmDynamicLevel)
 	with _ ->
 		1
 	in
 	if dynamic_level < 0 || dynamic_level > 2 then failwith "Invalid value for -D jvm.dynamic-level: Must be >=0 and <= 2";
 	let gctx = {
-		com = com;
+		gctx = gctx;
 		out = out;
-		t_runtime_exception = TInst(resolve_class com (["java";"lang"],"RuntimeException"),[]);
+		t_runtime_exception = TInst(resolve_class gctx (["java";"lang"],"RuntimeException"),[]);
 		entry_point = entry_point;
-		t_exception = TInst(resolve_class com (["java";"lang"],"Exception"),[]);
-		t_throwable = TInst(resolve_class com (["java";"lang"],"Throwable"),[]);
+		t_exception = TInst(resolve_class gctx (["java";"lang"],"Exception"),[]);
+		t_throwable = TInst(resolve_class gctx (["java";"lang"],"Throwable"),[]);
 		anon_identification = anon_identification;
 		preprocessor = Obj.magic ();
 		typedef_interfaces = Obj.magic ();
@@ -3118,14 +3117,14 @@ let generate jvm_flag com =
 		default_export_config = {
 			export_debug = true;
 		};
-		detail_times = Common.raw_defined com "jvm_times";
+		detail_times = Gctx.raw_defined gctx "jvm_times";
 		timer = new Timer.timer ["generate";"java"];
 		jar_compression_level = compression_level;
 		dynamic_level = dynamic_level;
 		functional_interfaces = [];
 	} in
 	Hashtbl.add gctx.known_typed_functions haxe_function_path ();
-	gctx.preprocessor <- new preprocessor com.basic (jsignature_of_type gctx);
+	gctx.preprocessor <- new preprocessor gctx.gctx.basic (jsignature_of_type gctx);
 	gctx.typedef_interfaces <- new typedef_interfaces gctx.preprocessor#get_infos anon_identification;
 	gctx.typedef_interfaces#add_interface_rewrite (["haxe";"root"],"Iterator") (["java";"util"],"Iterator") true;
 	let class_paths = ExtList.List.filter_map (fun java_lib ->
@@ -3142,13 +3141,13 @@ let generate jvm_flag com =
 			close_out ch_out;
 			Some (Printf.sprintf "lib/%s \n" name)
 		end
-	) com.native_libs.java_libs in
+	) gctx.gctx.native_libs in
 	Hashtbl.iter (fun name v ->
 		let filename = StringHelper.escape_res_name name ['/';'-'] in
 		gctx.out#add_entry v filename;
-	) com.resources;
+	) gctx.gctx.resources;
 	let generate_real_types () =
-		List.iter (generate_module_type gctx) com.types;
+		List.iter (generate_module_type gctx) gctx.gctx.types;
 	in
 	let generate_typed_interfaces () =
 		Hashtbl.iter (fun _ c -> generate_module_type gctx (TClassDecl c)) gctx.typedef_interfaces#get_interfaces;
diff --git a/src/generators/genlua.ml b/src/generators/genlua.ml
index cab664cb4d6..b0bb638f4fd 100644
--- a/src/generators/genlua.ml
+++ b/src/generators/genlua.ml
@@ -23,7 +23,7 @@
 open Extlib_leftovers
 open Ast
 open Type
-open Common
+open Gctx
 open ExtList
 open Error
 open JsSourcemap
@@ -31,7 +31,7 @@ open JsSourcemap
 type pos = Globals.pos
 
 type ctx = {
-    com : Common.context;
+    com : Gctx.t;
     buf : Buffer.t;
     packages : (string list,unit) Hashtbl.t;
     smap : sourcemap option;
@@ -137,8 +137,8 @@ let static_field c s =
     | "length" | "name" when not (has_class_flag c CExtern) || Meta.has Meta.HxGen c.cl_meta-> "._hx" ^ s
     | s -> field s
 
-let has_feature ctx = Common.has_feature ctx.com
-let add_feature ctx = Common.add_feature ctx.com
+let has_feature ctx = Gctx.has_feature ctx.com
+let add_feature ctx = Gctx.add_feature ctx.com
 
 let temp ctx =
     ctx.id_counter <- ctx.id_counter + 1;
@@ -458,7 +458,7 @@ and gen_call ctx e el =
      | TIdent "__lua__", [{ eexpr = TConst (TString code) }] ->
          spr ctx (String.concat "\n" (ExtString.String.nsplit code "\r\n"))
      | TIdent "__lua__", { eexpr = TConst (TString code); epos = p } :: tl ->
-         Codegen.interpolate_code ctx.com code tl (spr ctx) (gen_expr ctx) p
+         Codegen.interpolate_code ctx.com.error code tl (spr ctx) (gen_expr ctx) p
      | TIdent "__type__",  [o] ->
          spr ctx "type";
          gen_paren ctx [o];
@@ -1886,7 +1886,7 @@ let generate_type_forward ctx = function
 
 let alloc_ctx com =
     let smap =
-		if com.debug || Common.defined com Define.SourceMap then
+		if com.debug || Gctx.defined com Define.SourceMap then
 			Some {
 				source_last_pos = { file = 0; line = 0; col = 0};
 				print_comma = false;
@@ -1919,10 +1919,10 @@ let alloc_ctx com =
         type_accessor = (fun _ -> Globals.die "" __LOC__);
         separator = false;
         found_expose = false;
-        lua_jit = Common.defined com Define.LuaJit;
-        lua_vanilla = Common.defined com Define.LuaVanilla;
+        lua_jit = Gctx.defined com Define.LuaJit;
+        lua_vanilla = Gctx.defined com Define.LuaVanilla;
         lua_ver = try
-                float_of_string (Common.defined_value com Define.LuaVer)
+                float_of_string (Gctx.defined_value com Define.LuaVer)
             with | Not_found -> 5.2;
     } in
     ctx.type_accessor <- (fun t ->
@@ -2009,7 +2009,7 @@ let transform_multireturn ctx = function
 let generate com =
     let ctx = alloc_ctx com in
 
-    Codegen.map_source_header com (fun s -> print ctx "-- %s\n" s);
+    Gctx.map_source_header com.defines (fun s -> print ctx "-- %s\n" s);
 
     if has_feature ctx "Class" || has_feature ctx "Type.getClassName" then add_feature ctx "lua.Boot.isClass";
     if has_feature ctx "Enum" || has_feature ctx "Type.getEnumName" then add_feature ctx "lua.Boot.isEnum";
@@ -2019,20 +2019,22 @@ let generate com =
         print ctx "%s\n" file_content;
     in
 
+	let find_file f = (com.class_paths#find_file f).file in
+
     (* base table-to-array helpers and metatables *)
-    print_file (Common.find_file com "lua/_lua/_hx_tab_array.lua");
+    print_file (find_file "lua/_lua/_hx_tab_array.lua");
 
     (* base lua "toString" functionality for haxe objects*)
-    print_file (Common.find_file com "lua/_lua/_hx_tostring.lua");
+    print_file (find_file "lua/_lua/_hx_tostring.lua");
 
     (* base lua metatables for prototypes, inheritance, etc. *)
-    print_file (Common.find_file com "lua/_lua/_hx_anon.lua");
+    print_file (find_file "lua/_lua/_hx_anon.lua");
 
     (* Helpers for creating metatables from prototypes *)
-    print_file (Common.find_file com "lua/_lua/_hx_objects.lua");
+    print_file (find_file "lua/_lua/_hx_objects.lua");
 
     (* base runtime class stubs for haxe value types (Int, Float, etc) *)
-    print_file (Common.find_file com "lua/_lua/_hx_classes.lua");
+    print_file (find_file "lua/_lua/_hx_classes.lua");
 
     let include_files = List.rev com.include_files in
     List.iter (fun file ->
@@ -2122,18 +2124,18 @@ let generate com =
 
     (* If bit ops are manually imported include the haxe wrapper for them *)
     if has_feature ctx "use._bitop" then begin
-        print_file (Common.find_file com "lua/_lua/_hx_bit.lua");
+        print_file (find_file "lua/_lua/_hx_bit.lua");
     end;
 
     (* integer clamping is always required, and will use bit ops if available *)
-    print_file (Common.find_file com "lua/_lua/_hx_bit_clamp.lua");
+    print_file (find_file "lua/_lua/_hx_bit_clamp.lua");
 
     (* Array is required, always patch it *)
     println ctx "_hx_array_mt.__index = Array.prototype";
     newline ctx;
 
     (* Functions to support auto-run of libuv loop *)
-    print_file (Common.find_file com "lua/_lua/_hx_luv.lua");
+    print_file (find_file "lua/_lua/_hx_luv.lua");
 
     let b = open_block ctx in
     (* Localize init variables inside a do-block *)
@@ -2148,45 +2150,45 @@ let generate com =
     newline ctx;
 
     if has_feature ctx "use._hx_bind" then begin
-        print_file (Common.find_file com "lua/_lua/_hx_bind.lua");
+        print_file (find_file "lua/_lua/_hx_bind.lua");
     end;
 
     if has_feature ctx "use._hx_staticToInstance" then begin
-        print_file (Common.find_file com "lua/_lua/_hx_static_to_instance.lua");
+        print_file (find_file "lua/_lua/_hx_static_to_instance.lua");
     end;
 
     if has_feature ctx "use._hx_funcToField" then begin
-        print_file (Common.find_file com "lua/_lua/_hx_func_to_field.lua");
+        print_file (find_file "lua/_lua/_hx_func_to_field.lua");
     end;
 
     if has_feature ctx "Math.random" then begin
-        print_file (Common.find_file com "lua/_lua/_hx_random_init.lua");
+        print_file (find_file "lua/_lua/_hx_random_init.lua");
     end;
 
     if has_feature ctx "use._hx_print" then
-        print_file (Common.find_file com "lua/_lua/_hx_print.lua");
+        print_file (find_file "lua/_lua/_hx_print.lua");
 
     if has_feature ctx "use._hx_apply_self" then begin
-        print_file (Common.find_file com "lua/_lua/_hx_apply_self.lua");
+        print_file (find_file "lua/_lua/_hx_apply_self.lua");
     end;
 
     if has_feature ctx "use._hx_box_mr" then begin
-        print_file (Common.find_file com "lua/_lua/_hx_box_mr.lua");
+        print_file (find_file "lua/_lua/_hx_box_mr.lua");
     end;
 
     if has_feature ctx "use._hx_table" then begin
-        print_file (Common.find_file com "lua/_lua/_hx_table.lua");
+        print_file (find_file "lua/_lua/_hx_table.lua");
     end;
 
     if has_feature ctx "use._hx_wrap_if_string_field" then begin
-        print_file (Common.find_file com "lua/_lua/_hx_wrap_if_string_field.lua");
+        print_file (find_file "lua/_lua/_hx_wrap_if_string_field.lua");
     end;
 
     if has_feature ctx "use._hx_dyn_add" then begin
-        print_file (Common.find_file com "lua/_lua/_hx_dyn_add.lua");
+        print_file (find_file "lua/_lua/_hx_dyn_add.lua");
     end;
 
-    print_file (Common.find_file com "lua/_lua/_hx_handle_error.lua");
+    print_file (find_file "lua/_lua/_hx_handle_error.lua");
 
     println ctx "_hx_static_init();";
 
diff --git a/src/generators/genneko.ml b/src/generators/genneko.ml
index 29a43826933..13b7cd0cabe 100644
--- a/src/generators/genneko.ml
+++ b/src/generators/genneko.ml
@@ -21,11 +21,11 @@ open Ast
 open Globals
 open Type
 open Nast
-open Common
+open Gctx
 
 type context = {
 	version : int;
-	com : Common.context;
+	com : Gctx.t;
 	packages : (string list, unit) Hashtbl.t;
 	globals : (string list * string, string) Hashtbl.t;
 	mutable curglobal : int;
@@ -50,7 +50,7 @@ let pos ctx p =
 			try
 				Hashtbl.find files p.pfile
 			with Not_found ->
-				let path = (match Common.defined ctx.com Common.Define.AbsolutePath with
+				let path = (match Gctx.defined ctx.com Define.AbsolutePath with
 				| true -> if (Filename.is_relative p.pfile)
 					then Filename.concat (Sys.getcwd()) p.pfile
 					else p.pfile
@@ -371,7 +371,7 @@ and gen_expr ctx e =
 	| TCast (e,None) ->
 		gen_expr ctx e
 	| TCast (e1,Some t) ->
-		gen_expr ctx (Codegen.default_cast ~vtmp:"@tmp" ctx.com e1 t e.etype e.epos)
+		gen_expr ctx (Codegen.default_cast ~vtmp:"@tmp" ctx.com.basic ctx.com.std e1 t e.etype e.epos)
 	| TIdent s ->
 		ident p s
 	| TSwitch {switch_subject = e;switch_cases = cases;switch_default = eo} ->
@@ -771,19 +771,19 @@ let build ctx types =
 	let vars = List.concat (List.map (gen_static_vars ctx) types) in
 	packs @ methods @ boot :: names @ inits @ vars
 
-let generate com =
+let generate neko_lib_paths com =
 	Hashtbl.clear files;
-	let ctx = new_context com (if Common.defined com Define.NekoV1 then 1 else 2) false in
+	let ctx = new_context com (if Gctx.defined com Define.NekoV1 then 1 else 2) false in
 	let libs = (EBlock
-		(if Common.defined com Define.NekoNoHaxelibPaths then []
-		else generate_libs_init com.neko_lib_paths),
+		(if Gctx.defined com Define.NekoNoHaxelibPaths then []
+		else generate_libs_init neko_lib_paths),
 		{ psource = "<header>"; pline = 1; }
 	) in
 	let el = build ctx com.types in
 	let emain = (match com.main.main_expr with None -> [] | Some e -> [gen_expr ctx e]) in
 	let e = (EBlock ((header()) @ libs :: el @ emain), null_pos) in
-	let source = Common.defined com Define.NekoSource in
-	let use_nekoc = Common.defined com Define.UseNekoc in
+	let source = Gctx.defined com Define.NekoSource in
+	let use_nekoc = Gctx.defined com Define.UseNekoc in
 	if not use_nekoc then begin
 		try
 			Path.mkdir_from_path com.file;
@@ -791,7 +791,7 @@ let generate com =
 			Nbytecode.write ch (Ncompile.compile ctx.version e);
 			IO.close_out ch;
 		with Ncompile.Error (msg,pos) ->
-			let pfile = Common.find_file com pos.psource in
+			let pfile = Gctx.find_file com pos.psource in
 			let rec loop p =
 				let pp = { pfile = pfile; pmin = p; pmax = p; } in
 				if Lexer.get_error_line pp >= pos.pline then
diff --git a/src/generators/genphp7.ml b/src/generators/genphp7.ml
index c89e41b3e55..2cd92e8f6b0 100644
--- a/src/generators/genphp7.ml
+++ b/src/generators/genphp7.ml
@@ -3,8 +3,8 @@
 *)
 
 open Ast
+open Gctx
 open Type
-open Common
 open Meta
 open Globals
 open Sourcemaps
@@ -72,7 +72,7 @@ type used_type = {
 }
 
 type php_generator_context = {
-	pgc_common : Common.context;
+	pgc_common : Gctx.t;
 	(** Do not add comments with Haxe positions before each line of generated php code *)
 	pgc_skip_line_directives : bool;
 	(** The value of `-D php-prefix=value` split by dots *)
@@ -2011,8 +2011,6 @@ class code_writer (ctx:php_generator_context) hx_type_path php_name =
 			@see http://old.haxe.org/doc/advanced/magic#php-magic
 		*)
 		method write_expr_magic name args =
-			let msg = "untyped " ^ name ^ " is deprecated. Use php.Syntax instead." in
-			DeprecationCheck.warn_deprecation (DeprecationCheck.create_context ctx.pgc_common) msg self#pos;
 			let error = ("Invalid arguments for " ^ name ^ " magic call") in
 			match args with
 				| [] -> fail ~msg:error self#pos __LOC__
@@ -2021,7 +2019,7 @@ class code_writer (ctx:php_generator_context) hx_type_path php_name =
 						| "__php__" ->
 							(match expr.eexpr with
 								| TConst (TString php) ->
-									Codegen.interpolate_code ctx.pgc_common php args self#write self#write_expr self#pos
+									Codegen.interpolate_code ctx.pgc_common.error php args self#write self#write_expr self#pos
 								| _ -> fail self#pos __LOC__
 							)
 						| "__call__" ->
@@ -2445,7 +2443,7 @@ class code_writer (ctx:php_generator_context) hx_type_path php_name =
 						)
 						args
 					in
-					Codegen.interpolate_code ctx.pgc_common php args self#write self#write_expr self#pos
+					Codegen.interpolate_code ctx.pgc_common.error php args self#write self#write_expr self#pos
 				| _ -> ctx.pgc_common.error "First argument of php.Syntax.code() must be a constant string." self#pos
 		(**
 			Writes error suppression operator (for `php.Syntax.suppress()`)
@@ -3045,7 +3043,7 @@ class virtual type_builder ctx (wrapper:type_wrapper) =
 			writer#indent 0;
 			writer#write_line "<?php";
 			writer#write_line "/**";
-			Codegen.map_source_header ctx.pgc_common (fun s -> writer#write_line (" * " ^ s));
+			Gctx.map_source_header ctx.pgc_common.defines (fun s -> writer#write_line (" * " ^ s));
 			if ctx.pgc_common.debug then writer#write_line (" * Haxe source file: " ^ self#get_source_file);
 			writer#write_line " */";
 			writer#write "\n";
@@ -3944,7 +3942,7 @@ class generator (ctx:php_generator_context) =
 			and name = builder#get_name in
 			let filename = (create_dir_recursive (build_dir :: namespace)) ^ "/" ^ name ^ ".php" in
 			let channel = open_out filename in
-			if Common.defined ctx.pgc_common Define.SourceMap then
+			if Gctx.defined ctx.pgc_common Define.SourceMap then
 				builder#set_sourcemap_generator (new sourcemap_builder filename);
 			output_string channel builder#get_contents;
 			close_out channel;
@@ -3993,7 +3991,7 @@ class generator (ctx:php_generator_context) =
 			match self#get_entry_point with
 				| None -> ()
 				| Some (uses, entry_point) ->
-					let filename = Common.defined_value_safe ~default:"index.php" ctx.pgc_common Define.PhpFront in
+					let filename = Gctx.defined_value_safe ~default:"index.php" ctx.pgc_common Define.PhpFront in
 					let front_dirs = split_file_path (Filename.dirname filename) in
 					if front_dirs <> [] then
 						ignore(create_dir_recursive (root_dir :: front_dirs));
@@ -4032,7 +4030,7 @@ class generator (ctx:php_generator_context) =
 			Returns path from `index.php` to directory which will contain all generated classes
 		*)
 		method private get_lib_path : string list =
-			let path = Common.defined_value_safe ~default:"lib" ctx.pgc_common Define.PhpLib in
+			let path = Gctx.defined_value_safe ~default:"lib" ctx.pgc_common Define.PhpLib in
 			split_file_path path
 		(**
 			Returns PHP code for entry point
@@ -4069,12 +4067,12 @@ let get_boot com : tclass =
 (**
 	Entry point to Genphp7
 *)
-let generate (com:context) =
+let generate (com:Gctx.t) =
 	let ctx =
 		{
 			pgc_common = com;
-			pgc_skip_line_directives = Common.defined com Define.RealPosition;
-			pgc_prefix = Str.split (Str.regexp "\\.") (Common.defined_value_safe com Define.PhpPrefix);
+			pgc_skip_line_directives = Gctx.defined com Define.RealPosition;
+			pgc_prefix = Str.split (Str.regexp "\\.") (Gctx.defined_value_safe com Define.PhpPrefix);
 			pgc_boot = get_boot com;
 			pgc_namespaces_types_cache = Hashtbl.create 512;
 			pgc_anons = Hashtbl.create 0;
diff --git a/src/generators/genpy.ml b/src/generators/genpy.ml
index c170bd436ca..e58d05dcc90 100644
--- a/src/generators/genpy.ml
+++ b/src/generators/genpy.ml
@@ -21,7 +21,7 @@ open Globals
 open Ast
 open Error
 open Type
-open Common
+open Gctx
 open Texpr.Builder
 
 module Utils = struct
@@ -955,7 +955,8 @@ module Transformer = struct
 			let r = { a_expr with eexpr = TArrayDecl exprs } in
 			lift_expr ae.a_next_id ~blocks:blocks r
 		| (is_value, TCast(e1,Some mt)) ->
-			let e = Codegen.default_cast ~vtmp:(ae.a_next_id()) (match !como with Some com -> com | None -> die "" __LOC__) e1 mt ae.a_expr.etype ae.a_expr.epos in
+			let com = (match !como with Some com -> com | None -> die "" __LOC__) in
+			let e = Codegen.default_cast ~vtmp:(ae.a_next_id()) com.basic com.std e1 mt ae.a_expr.etype ae.a_expr.epos in
 			transform_expr ae.a_next_id ~is_value:is_value e
 		| (is_value, TCast(e,None)) ->
 			let e = trans is_value [] e in
@@ -999,12 +1000,12 @@ module Printer = struct
 		pc_indent : string;
 		pc_next_anon_func : unit -> string;
 		pc_debug : bool;
-		pc_com : Common.context;
+		pc_com : Gctx.t;
 	}
 
-	let has_feature pctx = Common.has_feature pctx.pc_com
+	let has_feature pctx = Gctx.has_feature pctx.pc_com
 
-	let add_feature pctx = Common.add_feature pctx.pc_com
+	let add_feature pctx = Gctx.add_feature pctx.pc_com
 
 	let create_context =
 		let n = ref (-1) in
@@ -1491,11 +1492,9 @@ module Printer = struct
 			| ("python_Syntax.code"),({ eexpr = TConst (TString code) } as ecode) :: tl ->
 				let buf = Buffer.create 0 in
 				let interpolate () =
-					Codegen.interpolate_code pctx.pc_com code tl (Buffer.add_string buf) (fun e -> Buffer.add_string buf (print_expr pctx e)) ecode.epos
+					Codegen.interpolate_code pctx.pc_com.error code tl (Buffer.add_string buf) (fun e -> Buffer.add_string buf (print_expr pctx e)) ecode.epos
 				in
-				let old = pctx.pc_com.error_ext in
-				pctx.pc_com.error_ext <- (fun err -> raise (Error.Fatal_error err));
-				Std.finally (fun() -> pctx.pc_com.error_ext <- old) interpolate ();
+				interpolate ();
 				Buffer.contents buf
 			| ("python_Syntax._pythonCode"), [e] ->
 				print_expr pctx e
@@ -1673,7 +1672,7 @@ end
 
 module Generator = struct
 	type context = {
-		com : Common.context;
+		com : Gctx.t;
 		buf : Buffer.t;
 		packages : (string,int) Hashtbl.t;
 		mutable static_inits : (unit -> unit) list;
@@ -1683,8 +1682,8 @@ module Generator = struct
 		print_time : float;
 	}
 
-	let has_feature ctx = Common.has_feature ctx.com
-	let add_feature ctx = Common.add_feature ctx.com
+	let has_feature ctx = Gctx.has_feature ctx.com
+	let add_feature ctx = Gctx.add_feature ctx.com
 
 	type class_field_infos = {
 		cfd_fields : string list;
@@ -2427,7 +2426,7 @@ module Generator = struct
 	let run com =
 		Transformer.init com;
 		let ctx = mk_context com in
-		Codegen.map_source_header com (fun s -> print ctx "# %s\n# coding: utf-8\n" s);
+		Gctx.map_source_header com.defines (fun s -> print ctx "# %s\n# coding: utf-8\n" s);
 		if has_feature ctx "closure_Array" || has_feature ctx "closure_String" then
 			spr ctx "from functools import partial as _hx_partial\n";
 		spr ctx "import sys\n";
diff --git a/src/generators/genswf.ml b/src/generators/genswf.ml
index db182a137c0..5b594b7b9e6 100644
--- a/src/generators/genswf.ml
+++ b/src/generators/genswf.ml
@@ -21,7 +21,7 @@ open As3hl
 open ExtString
 open Type
 open Error
-open Common
+open Gctx
 open Ast
 open Globals
 open NativeLibraries
@@ -32,14 +32,35 @@ let tag ?(ext=false) d = {
 	tdata = d;
 }
 
-let convert_header com (w,h,fps,bg) =
+let flash_version_tag = function
+	| 6. -> 6
+	| 7. -> 7
+	| 8. -> 8
+	| 9. -> 9
+	| 10. | 10.1 -> 10
+	| 10.2 -> 11
+	| 10.3 -> 12
+	| 11. -> 13
+	| 11.1 -> 14
+	| 11.2 -> 15
+	| 11.3 -> 16
+	| 11.4 -> 17
+	| 11.5 -> 18
+	| 11.6 -> 19
+	| 11.7 -> 20
+	| 11.8 -> 21
+	| 11.9 -> 22
+	| v when v >= 12.0 && float_of_int (int_of_float v) = v -> int_of_float v + 11
+	| v -> failwith ("Invalid SWF version " ^ string_of_float v)
+
+let convert_header com flash_version (w,h,fps,bg) =
 	let high = (max w h) * 20 in
 	let rec loop b =
 		if 1 lsl b > high then b else loop (b + 1)
 	in
 	let bits = loop 0 in
 	{
-		h_version = Common.flash_version_tag com.flash_version;
+		h_version = flash_version_tag flash_version;
 		h_size = {
 			rect_nbits = bits + 1;
 			left = 0;
@@ -49,11 +70,11 @@ let convert_header com (w,h,fps,bg) =
 		};
 		h_frame_count = 1;
 		h_fps = to_float16 (if fps > 127.0 then 127.0 else fps);
-		h_compressed = not (Common.defined com Define.NoSwfCompress);
+		h_compressed = not (Gctx.defined com Define.NoSwfCompress);
 	} , bg
 
-let default_header com =
-	convert_header com (400,300,30.,0xFFFFFF)
+let default_header com flash_version =
+	convert_header com flash_version (400,300,30.,0xFFFFFF)
 
 type dependency_kind =
 	| DKInherit
@@ -223,7 +244,7 @@ let detect_format data p =
 		abort "Unknown file format" p
 
 let build_swf9 com file swc =
-	let boot_name = if swc <> None || Common.defined com Define.HaxeBoot then "haxe" else "boot_" ^ (String.sub (Digest.to_hex (Digest.string (Filename.basename file))) 0 4) in
+	let boot_name = if swc <> None || Gctx.defined com Define.HaxeBoot then "haxe" else "boot_" ^ (String.sub (Digest.to_hex (Digest.string (Filename.basename file))) 0 4) in
 	let code = Genswf9.generate com boot_name in
 	let code = (match swc with
 	| Some cat ->
@@ -256,7 +277,7 @@ let build_swf9 com file swc =
 		tag (TBinaryData (!cid,data)) :: acc
 	) com.resources [] in
 	let load_file_data file p =
-		let file = try Common.find_file com file with Not_found -> file in
+		let file = try Gctx.find_file com  file with Not_found -> file in
 		if String.length file > 5 && String.sub file 0 5 = "data:" then
 			String.sub file 5 (String.length file - 5)
 		else
@@ -435,12 +456,12 @@ let build_swf9 com file swc =
 	let clips = [tag (TF9Classes (List.rev !classes))] in
 	res @ bmp @ code @ clips
 
-let merge com file priority (h1,tags1) (h2,tags2) =
+let merge com flash_version file priority (h1,tags1) (h2,tags2) =
 	(* prioritize header+bgcolor for first swf *)
-	let header = if priority then { h2 with h_version = max h2.h_version (Common.flash_version_tag com.flash_version) } else h1 in
+	let header = if priority then { h2 with h_version = max h2.h_version (flash_version_tag flash_version) } else h1 in
 	let tags1 = if priority then List.filter (function { tdata = TSetBgColor _ } -> false | _ -> true) tags1 else tags1 in
 	(* remove unused tags *)
-	let use_stage = priority && Common.defined com Define.FlashUseStage in
+	let use_stage = priority && Gctx.defined com Define.FlashUseStage in
 	let classes = ref [] in
 	let nframe = ref 0 in
 	let tags2 = List.filter (fun t ->
@@ -451,9 +472,9 @@ let merge com file priority (h1,tags1) (h2,tags2) =
 		| TRemoveObject _ -> use_stage
 		| TShowFrame -> incr nframe; use_stage
 		| TFilesAttributes _ | TEnableDebugger2 _ | TScenes _ -> false
-		| TMetaData _ -> not (Common.defined com Define.SwfMetadata)
+		| TMetaData _ -> not (Gctx.defined com Define.SwfMetadata)
 		| TSetBgColor _ -> priority
-		| TExport el when !nframe = 0 && com.flash_version >= 9. ->
+		| TExport el when !nframe = 0 && flash_version >= 9. ->
 			let el = List.filter (fun e ->
 				let path = parse_path e.exp_name in
 				let b = List.exists (fun t -> t_path t = path) com.types in
@@ -508,8 +529,8 @@ let merge com file priority (h1,tags1) (h2,tags2) =
 	let tags = loop tags1 tags2 in
 	header, tags
 
-let generate swf_header com =
-	let swc = if Common.defined com Define.Swc then Some (ref "") else None in
+let generate swf_header swf_libs flash_version com =
+	let swc = if Gctx.defined com Define.Swc then Some (ref "") else None in
 	let file , codeclip = (try let f , c = ExtString.String.split com.file "@" in f, Some c with _ -> com.file , None) in
 	(* list exports *)
 	let exports = Hashtbl.create 0 in
@@ -541,39 +562,39 @@ let generate swf_header com =
 				) el
 			| _ -> ()
 		) tags;
-	) com.native_libs.swf_libs;
+	) swf_libs;
 	(* build haxe swf *)
 	let tags = build_swf9 com file swc in
-	let header, bg = (match swf_header with None -> default_header com | Some h -> convert_header com h) in
+	let header, bg = (match swf_header with None -> default_header com flash_version | Some h -> convert_header com flash_version h) in
 	let bg = tag (TSetBgColor { cr = bg lsr 16; cg = (bg lsr 8) land 0xFF; cb = bg land 0xFF }) in
 	let scene = tag ~ext:true (TScenes ([(0,"Scene1")],[])) in
 	let swf_debug_password = try
-		Digest.to_hex(Digest.string (Common.defined_value com Define.SwfDebugPassword))
+		Digest.to_hex(Digest.string (Gctx.defined_value com Define.SwfDebugPassword))
 	with Not_found ->
 		""
 	in
-	let debug = (if Common.defined com Define.Fdb then [tag (TEnableDebugger2 (0, swf_debug_password))] else []) in
+	let debug = (if Gctx.defined com Define.Fdb then [tag (TEnableDebugger2 (0, swf_debug_password))] else []) in
 	let meta_data =
 		try
-			let file = Common.defined_value com Define.SwfMetadata in
-			let file = try Common.find_file com file with Not_found -> file in
+			let file = Gctx.defined_value com Define.SwfMetadata in
+			let file = try Gctx.find_file com file with Not_found -> file in
 			let data = try Std.input_file ~bin:true file with Sys_error _ -> failwith ("Metadata resource file not found : " ^ file) in
 			[tag(TMetaData (data))]
 		with Not_found ->
 			[]
 	in
-	let fattr = (if com.flash_version < 8. then [] else
+	let fattr = (if flash_version < 8. then [] else
 		[tag (TFilesAttributes {
-			fa_network = Common.defined com Define.NetworkSandbox;
+			fa_network = Gctx.defined com Define.NetworkSandbox;
 			fa_as3 = true;
 			fa_metadata = meta_data <> [];
-			fa_gpu = com.flash_version > 9. && Common.defined com Define.SwfGpu;
-			fa_direct_blt = com.flash_version > 9. && Common.defined com Define.SwfDirectBlit;
+			fa_gpu = flash_version > 9. && Gctx.defined com Define.SwfGpu;
+			fa_direct_blt = flash_version > 9. && Gctx.defined com Define.SwfDirectBlit;
 		})]
 	) in
-	let fattr = if Common.defined com Define.AdvancedTelemetry then fattr @ [tag (TUnknown (0x5D,"\x00\x00"))] else fattr in
+	let fattr = if Gctx.defined com Define.AdvancedTelemetry then fattr @ [tag (TUnknown (0x5D,"\x00\x00"))] else fattr in
 	let swf_script_limits = try
-		let s = Common.defined_value com Define.SwfScriptTimeout in
+		let s = Gctx.defined_value com Define.SwfScriptTimeout in
 		let i = try int_of_string s with _ -> abort "Argument to swf_script_timeout must be an integer" null_pos in
 		[tag(TScriptLimits (256, if i < 0 then 0 else if i > 65535 then 65535 else i))]
 	with Not_found ->
@@ -583,12 +604,12 @@ let generate swf_header com =
 	(* merge swf libraries *)
 	let priority = ref (swf_header = None) in
 	let swf = List.fold_left (fun swf swf_lib ->
-		let swf = merge com file !priority swf (SwfLoader.remove_classes toremove swf_lib#get_data swf_lib#list_modules) in
+		let swf = merge com flash_version file !priority swf (SwfLoader.remove_classes toremove swf_lib#get_data swf_lib#list_modules) in
 		priority := false;
 		swf
-	) swf com.native_libs.swf_libs in
+	) swf swf_libs in
 	let swf = match swf with
-	| header,tags when Common.defined com Define.SwfPreloaderFrame ->
+	| header,tags when Gctx.defined com Define.SwfPreloaderFrame ->
 		let rec loop l =
 			match l with
 			| ({tdata = TFilesAttributes _ | TUnknown (0x5D,"\x00\x00") | TMetaData _ | TSetBgColor _ | TEnableDebugger2 _ | TScriptLimits _} as t) :: l -> t :: loop l
@@ -599,7 +620,7 @@ let generate swf_header com =
 	| _ -> swf in
 	(* write swf/swc *)
 	let t = Timer.timer ["write";"swf"] in
-	let level = (try int_of_string (Common.defined_value com Define.SwfCompressLevel) with Not_found -> 9) in
+	let level = (try int_of_string (Gctx.defined_value com Define.SwfCompressLevel) with Not_found -> 9) in
 	SwfParser.init Extc.input_zip (Extc.output_zip ~level);
 	(match swc with
 	| Some cat ->
diff --git a/src/generators/genswf9.ml b/src/generators/genswf9.ml
index 828a353b875..a414330b45b 100644
--- a/src/generators/genswf9.ml
+++ b/src/generators/genswf9.ml
@@ -19,11 +19,11 @@
 open Extlib_leftovers
 open Globals
 open Ast
+open Gctx
 open Type
 open Error
 open As3
 open As3hl
-open Common
 open FlashProps
 
 type read = Read
@@ -81,7 +81,7 @@ type try_infos = {
 
 type context = {
 	(* globals *)
-	com : Common.context;
+	com : Gctx.t;
 	debugger : bool;
 	swc : bool;
 	boot : path;
@@ -351,7 +351,7 @@ let property ctx fa t =
 	| TInst ({ cl_path = [],"Array" },_) ->
 		(match p with
 		| "length" -> ident p, Some KInt, false (* UInt in the spec *)
-		| "map" | "filter" when Common.defined ctx.com Define.NoFlashOverride -> ident (p ^ "HX"), None, true
+		| "map" | "filter" when Gctx.defined ctx.com Define.NoFlashOverride -> ident (p ^ "HX"), None, true
 		| "copy" | "insert" | "contains" | "remove" | "iterator" | "keyValueIterator"
 		| "toString" | "map" | "filter" | "resize" -> ident p , None, true
 		| _ -> as3 p, None, false);
@@ -364,13 +364,13 @@ let property ctx fa t =
 	| TInst ({ cl_path = [],"String" },_) ->
 		(match p with
 		| "length" (* Int in AS3/Haxe *) -> ident p, None, false
-		| "charCodeAt" when Common.defined ctx.com Define.NoFlashOverride -> ident (p ^ "HX"), None, true
+		| "charCodeAt" when Gctx.defined ctx.com Define.NoFlashOverride -> ident (p ^ "HX"), None, true
 		| "charCodeAt" (* use Haxe version *) -> ident p, None, true
 		| "cca" -> as3 "charCodeAt", None, false
 		| _ -> as3 p, None, false);
 	| TInst ({ cl_path = [],"Date" },_) ->
 		(match p with
-		| "toString" when Common.defined ctx.com Define.NoFlashOverride -> ident (p ^ "HX"), None, true
+		| "toString" when Gctx.defined ctx.com Define.NoFlashOverride -> ident (p ^ "HX"), None, true
 		| _ -> ident p, None, false)
 	| TAnon a ->
 		(match !(a.a_status) with
@@ -2833,7 +2833,7 @@ let generate_resource ctx name =
 let generate com boot_name =
 	let ctx = {
 		com = com;
-		need_ctor_skip = Common.has_feature com "Type.createEmptyInstance";
+		need_ctor_skip = Gctx.has_feature com "Type.createEmptyInstance";
 		handle_spread_args = (fun basic args t_result args_to_expr ->
 			match List.rev args with
 			| { eexpr = TUnop (Spread,Prefix,rest) } :: args_rev ->
@@ -2869,12 +2869,12 @@ let generate com boot_name =
 			| _ ->
 				None
 		);
-		debug = com.Common.debug;
+		debug = com.Gctx.debug;
 		cur_class = null_class;
 		boot = ([],boot_name);
-		debugger = Common.defined com Define.Fdb;
-		swc = Common.defined com Define.Swc;
-		swf_protected = Common.defined com Define.SwfProtected;
+		debugger = Gctx.defined com Define.Fdb;
+		swc = Gctx.defined com Define.Swc;
+		swf_protected = Gctx.defined com Define.SwfProtected;
 		code = DynArray.create();
 		locals = PMap.empty;
 		infos = default_infos();
diff --git a/src/generators/hl2c.ml b/src/generators/hl2c.ml
index 645e2982a8d..ea3989ed4a7 100644
--- a/src/generators/hl2c.ml
+++ b/src/generators/hl2c.ml
@@ -78,7 +78,7 @@ type context = {
 	mutable file_prefix : string;
 	mutable fun_index : int;
 	mutable type_module : (ttype, code_module) PMap.t;
-	gcon : Common.context;
+	gcon : Gctx.t;
 }
 
 let sprintf = Printf.sprintf
@@ -345,7 +345,7 @@ let short_digest str =
 let open_file ctx file =
 	if ctx.curfile <> "" then close_file ctx;
 	if file <> "hlc.json" then
-		Codegen.map_source_header ctx.gcon (fun s -> define ctx (sprintf "// %s" s));
+		Gctx.map_source_header ctx.gcon.defines (fun s -> define ctx (sprintf "// %s" s));
 	ctx.curfile <- file;
 	ctx.fun_index <- 0;
 	ctx.file_prefix <- (short_digest file) ^ "_"
@@ -1461,7 +1461,7 @@ let write_c com file (code:code) gnames =
 	let bnames = Array.map (fun b -> "bytes$" ^ short_digest (Digest.to_hex (Digest.bytes b))) code.bytes in
 
 	let ctx = {
-		version = com.Common.version;
+		version = com.Gctx.version;
 		out = Buffer.create 1024;
 		tabs = "";
 		hlcode = code;
@@ -1576,7 +1576,7 @@ let write_c com file (code:code) gnames =
 	in
 	Array.iteri (fun i str ->
 		if String.length str >= string_data_limit then begin
-			let s = Common.utf8_to_utf16 str true in
+			let s = StringHelper.utf8_to_utf16 str true in
 			sline "// %s..." (String.escaped (String.sub str 0 (string_data_limit-4)));
 			output ctx (Printf.sprintf "vbyte string$%s[] = {" (short_digest str));
 			output_bytes (output ctx) s;
diff --git a/src/generators/hlinterp.ml b/src/generators/hlinterp.ml
index 4de99859b52..82cf2afd5cd 100644
--- a/src/generators/hlinterp.ml
+++ b/src/generators/hlinterp.ml
@@ -292,7 +292,7 @@ let fstr = function
 	| FFun f -> "function@" ^ string_of_int f.findex
 	| FNativeFun (s,_,_) -> "native[" ^ s ^ "]"
 
-let caml_to_hl str = Common.utf8_to_utf16 str true
+let caml_to_hl str = StringHelper.utf8_to_utf16 str true
 
 let hash ctx str =
 	let h = hl_hash str in
@@ -317,7 +317,7 @@ let utf16_iter f s =
 	loop 0
 
 let utf16_char buf c =
-	Common.utf16_add buf (int_of_char c)
+	StringHelper.utf16_add buf (int_of_char c)
 
 let hl_to_caml str =
 	let utf16_eof s =
@@ -1776,9 +1776,9 @@ let load_native ctx lib name t =
 						if c >= int_of_char 'a' && c <= int_of_char 'z' then c + int_of_char 'A' - int_of_char 'a'
 						else c
 					in
-					Common.utf16_add buf c
+					StringHelper.utf16_add buf c
 				) (String.sub s (int pos) ((int len) lsl 1));
-				Common.utf16_add buf 0;
+				StringHelper.utf16_add buf 0;
 				VBytes (Buffer.contents buf)
 			| _ -> Globals.die "" __LOC__)
 		| "ucs2_lower" ->
@@ -1790,9 +1790,9 @@ let load_native ctx lib name t =
 						if c >= int_of_char 'A' && c <= int_of_char 'Z' then c + int_of_char 'a' - int_of_char 'A'
 						else c
 					in
-					Common.utf16_add buf c
+					StringHelper.utf16_add buf c
 				) (String.sub s (int pos) ((int len) lsl 1));
-				Common.utf16_add buf 0;
+				StringHelper.utf16_add buf 0;
 				VBytes (Buffer.contents buf)
 			| _ -> Globals.die "" __LOC__)
 		| "url_encode" ->
@@ -1800,8 +1800,8 @@ let load_native ctx lib name t =
 			| [VBytes s; VRef (r, HI32)] ->
 				let s = hl_to_caml s in
 				let buf = Buffer.create 0 in
-				Common.url_encode s (utf16_char buf);
-				Common.utf16_add buf 0;
+				StringHelper.url_encode s (utf16_char buf);
+				StringHelper.utf16_add buf 0;
 				let str = Buffer.contents buf in
 				set_ref r (to_int (String.length str lsr 1 - 1));
 				VBytes str
diff --git a/src/generators/jsSourcemap.ml b/src/generators/jsSourcemap.ml
index f44a2029162..01aad6ba3fd 100644
--- a/src/generators/jsSourcemap.ml
+++ b/src/generators/jsSourcemap.ml
@@ -19,7 +19,6 @@
 open Extlib_leftovers
 open Globals
 open Type
-open Common
 
 type sourcemap = {
 	sources : (string) DynArray.t;
@@ -131,7 +130,7 @@ let handle_newlines smap str =
 		loop 0
 	) smap
 
-let write_mappings (com : Common.context) smap source_path_prefix =
+let write_mappings (com : Gctx.t) smap source_path_prefix =
 	let basefile = Filename.basename com.file in
 	let channel = open_out_bin (com.file ^ ".map") in
 	let sources = DynArray.to_list smap.sources in
@@ -145,7 +144,7 @@ let write_mappings (com : Common.context) smap source_path_prefix =
 	output_string channel ("\"sources\":[" ^
 		(String.concat "," (List.map (fun s -> "\"" ^ source_path_prefix ^ to_url s ^ "\"") sources)) ^
 		"],\n");
-	if Common.defined com Define.SourceMapContent then begin
+	if Gctx.defined com Define.SourceMapContent then begin
 		output_string channel ("\"sourcesContent\":[" ^
 			(String.concat "," (List.map (fun s -> try "\"" ^ StringHelper.s_escape (Std.input_file ~bin:true s) ^ "\"" with _ -> "null") sources)) ^
 			"],\n");
diff --git a/src/macro/eval/evalStdLib.ml b/src/macro/eval/evalStdLib.ml
index 1191c9976cd..8f7ad7c3d83 100644
--- a/src/macro/eval/evalStdLib.ml
+++ b/src/macro/eval/evalStdLib.ml
@@ -2444,7 +2444,7 @@ end
 module StdStringTools = struct
 	let url_encode s =
 		let b = Buffer.create 0 in
-		Common.url_encode s (Buffer.add_char b);
+		StringHelper.url_encode s (Buffer.add_char b);
 		Buffer.contents b
 
 	let fastCodeAt = StdString.charCodeAt
diff --git a/src/macro/macroApi.ml b/src/macro/macroApi.ml
index c18b0bf1a55..79adeacd7bb 100644
--- a/src/macro/macroApi.ml
+++ b/src/macro/macroApi.ml
@@ -2013,7 +2013,7 @@ let macro_api ccom get_api =
 		"set_custom_js_generator", vfun1 (fun f ->
 			let f = prepare_callback f 1 in
 			(get_api()).set_js_generator (fun js_ctx ->
-				let com = ccom() in
+				let com = Common.to_gctx (ccom()) in
 				Genjs.setup_kwds com;
 				let api = encode_obj [
 					"outputFile", encode_string com.file;
@@ -2028,10 +2028,10 @@ let macro_api ccom get_api =
 						vbool (Hashtbl.mem Genjs.kwds (decode_string v))
 					);
 					"hasFeature", vfun1 (fun v ->
-						vbool (Common.has_feature com (decode_string v))
+						vbool (Gctx.has_feature com (decode_string v))
 					);
 					"addFeature", vfun1 (fun v ->
-						Common.add_feature com (decode_string v);
+						Gctx.add_feature com (decode_string v);
 						vnull
 					);
 					"quoteString", vfun1 (fun v ->
diff --git a/src/typing/macroContext.ml b/src/typing/macroContext.ml
index f83d5fe8921..7b5c23f3e6e 100644
--- a/src/typing/macroContext.ml
+++ b/src/typing/macroContext.ml
@@ -211,7 +211,7 @@ let make_macro_com_api com mcom p =
 		set_js_generator = (fun gen ->
 			com.js_gen <- Some (fun() ->
 				Path.mkdir_from_path com.file;
-				let js_ctx = Genjs.alloc_ctx com (get_es_version com) in
+				let js_ctx = Genjs.alloc_ctx (Common.to_gctx com) (Gctx.get_es_version com.defines) in
 				let t = macro_timer com ["jsGenerator"] in
 				gen js_ctx;
 				t()