write pos pairs where applicable

src/compiler/hxb/hxbReader.ml

@@ -158,6 +158,24 @@ class hxb_reader
 		} in
 		pos
 
+	method read_pos_pair =
+		let file = self#read_string in
+		let min1 = read_leb128 ch in
+		let max1 = read_leb128 ch in
+		let min2 = read_leb128 ch in
+		let max2 = read_leb128 ch in
+		let pos1 = {
+			pfile = file;
+			pmin = min1;
+			pmax = max1;
+		} in
+		let pos2 = {
+			pos1 with
+			pmin = pos1.pmin + min2;
+			pmax = pos1.pmin + max2;
+		} in
+		pos1,pos2
+
 	method read_metadata_entry : metadata_entry =
 		let name = self#read_string in
 		let p = self#read_pos in
@@ -271,8 +289,7 @@ class hxb_reader
 
 	method read_placed_type_path =
 		let tp = self#read_type_path in
-		let pfull = self#read_pos in
-		let ppath = self#read_pos in
+		let pfull,ppath = self#read_pos_pair in
 		{
 			path = tp;
 			pos_full = pfull;
@@ -1215,8 +1232,7 @@ class hxb_reader
 
 	method read_class_field_forward =
 		let name = self#read_string in
-		let pos = self#read_pos in
-		let name_pos = self#read_pos in
+		let pos,name_pos = self#read_pos_pair in
 		let overloads = self#read_list (fun () -> self#read_class_field_forward) in
 		{ null_field with cf_name = name; cf_pos = pos; cf_name_pos = name_pos; cf_overloads = overloads }
 
@@ -1671,8 +1687,7 @@ class hxb_reader
 		self#read_list (fun () ->
 			let kind = IO.read_byte ch in
 			let path = self#read_path in
-			let pos = self#read_pos in
-			let name_pos = self#read_pos in
+			let pos,name_pos = self#read_pos_pair in
 			let params = self#read_type_parameters_forward in
 			let mt = match kind with
 			| 0 ->
@@ -1712,8 +1727,7 @@ class hxb_reader
 
 				let read_field () =
 					let name = self#read_string in
-					let pos = self#read_pos in
-					let name_pos = self#read_pos in
+					let pos,name_pos = self#read_pos_pair in
 					let index = IO.read_byte ch in
 
 					{ null_enum_field with

src/compiler/hxb/hxbWriter.ml

@@ -568,6 +568,14 @@ module HxbWriter = struct
 		Chunk.write_leb128 writer.chunk p.pmin;
 		Chunk.write_leb128 writer.chunk p.pmax
 
+	let write_pos_pair writer (p1 : pos) (p2 : pos) =
+		(* Write second position offset relative to first position's pmin, which is often within 1 byte range. *)
+		Chunk.write_string writer.chunk p1.pfile;
+		Chunk.write_leb128 writer.chunk p1.pmin;
+		Chunk.write_leb128 writer.chunk p1.pmax;
+		Chunk.write_leb128 writer.chunk (p2.pmin - p1.pmin);
+		Chunk.write_leb128 writer.chunk (p2.pmax - p1.pmin)
+
 	let rec write_metadata_entry writer ((meta,el,p) : metadata_entry) =
 		Chunk.write_string writer.chunk (Meta.to_string meta);
 		write_pos writer p;
@@ -594,8 +602,7 @@ module HxbWriter = struct
 
 	and write_placed_type_path writer ptp =
 		write_type_path writer ptp.path;
-		write_pos writer ptp.pos_full;
-		write_pos writer ptp.pos_path
+		write_pos_pair writer ptp.pos_full ptp.pos_path
 
 	and write_type_param_or_const writer = function
 		| TPType th ->
@@ -1726,8 +1733,7 @@ module HxbWriter = struct
 
 	and write_class_field_forward writer cf =
 		Chunk.write_string writer.chunk cf.cf_name;
-		write_pos writer cf.cf_pos;
-		write_pos writer cf.cf_name_pos;
+		write_pos_pair writer cf.cf_pos cf.cf_name_pos;
 		Chunk.write_list writer.chunk cf.cf_overloads (fun cf ->
 			write_class_field_forward writer cf;
 		);
@@ -1965,8 +1971,7 @@ module HxbWriter = struct
 		let infos = t_infos mt in
 		Chunk.write_u8 writer.chunk i;
 		write_path writer (fst infos.mt_path, !name);
-		write_pos writer infos.mt_pos;
-		write_pos writer infos.mt_name_pos;
+		write_pos_pair writer infos.mt_pos infos.mt_name_pos;
 		write_type_parameters_forward writer infos.mt_params;
 		let params = new pool in
 		writer.type_type_parameters <- params;
@@ -2007,8 +2012,7 @@ module HxbWriter = struct
 		| TEnumDecl e ->
 			Chunk.write_list writer.chunk (PMap.foldi (fun s f acc -> (s,f) :: acc) e.e_constrs []) (fun (s,ef) ->
 				Chunk.write_string writer.chunk s;
-				write_pos writer ef.ef_pos;
-				write_pos writer ef.ef_name_pos;
+				write_pos_pair writer ef.ef_pos ef.ef_name_pos;
 				Chunk.write_u8 writer.chunk ef.ef_index
 			);
 		| TAbstractDecl a ->