Use compressed marshaling to write .cmt, .cmti, .cmi, .cmo, .cma files

For .cmi, .cmt and .cmti files, the resulting files are 35-40% the size of
the uncompressed files.

For .cmo and .cma files, we compress only the debug info; this gives 50%
space savings for files with full debug info.

4 files changed, 8 insertions, 6 deletions

diff --git a/bytecomp/bytepackager.ml b/bytecomp/bytepackager.ml
index 449d423252..4ff00f2967 100644
--- a/bytecomp/bytepackager.ml
+++ b/bytecomp/bytepackager.ml
@@ -272,8 +272,9 @@ let package_object_files ~ppf_dump files targetfile targetname coercion =
       build_global_target ~ppf_dump oc targetname state components coercion in
     let pos_debug = pos_out oc in
     if !Clflags.debug && state.events <> [] then begin
-      output_value oc (List.rev state.events);
-      output_value oc (String.Set.elements state.debug_dirs);
+      Marshal.(to_channel oc (List.rev state.events) [Compression]);
+      Marshal.(to_channel oc (String.Set.elements state.debug_dirs)
+                             [Compression]);
     end;
     let force_link =
       List.exists (function
diff --git a/bytecomp/emitcode.ml b/bytecomp/emitcode.ml
index 9e70bebd9c..bd3c3f2fb5 100644
--- a/bytecomp/emitcode.ml
+++ b/bytecomp/emitcode.ml
@@ -416,8 +416,9 @@ let to_file outchan unit_name objfile ~required_globals code =
         (Filename.dirname (Location.absolute_path objfile))
         !debug_dirs;
       let p = pos_out outchan in
-      output_value outchan !events;
-      output_value outchan (String.Set.elements !debug_dirs);
+      Marshal.(to_channel outchan !events [Compression]);
+      Marshal.(to_channel outchan (String.Set.elements !debug_dirs)
+                          [Compression]);
       (p, pos_out outchan - p)
     end else
       (0, 0) in
diff --git a/file_formats/cmi_format.ml b/file_formats/cmi_format.ml
index bd82cc3761..aa3d6777a0 100644
--- a/file_formats/cmi_format.ml
+++ b/file_formats/cmi_format.ml
@@ -84,7 +84,7 @@ let read_cmi filename =
 let output_cmi filename oc cmi =
 (* beware: the provided signature must have been substituted for saving *)
   output_string oc Config.cmi_magic_number;
-  output_value oc ((cmi.cmi_name, cmi.cmi_sign) : header);
+  Marshal.(to_channel oc ((cmi.cmi_name, cmi.cmi_sign) : header) [Compression]);
   flush oc;
   let crc = Digest.file filename in
   let crcs = (cmi.cmi_name, Some crc) :: cmi.cmi_crcs in
diff --git a/file_formats/cmt_format.ml b/file_formats/cmt_format.ml
index a493780e5a..8fa01e525b 100644
--- a/file_formats/cmt_format.ml
+++ b/file_formats/cmt_format.ml
@@ -109,7 +109,7 @@ let input_cmt ic = (input_value ic : cmt_infos)
 
 let output_cmt oc cmt =
   output_string oc Config.cmt_magic_number;
-  output_value oc (cmt : cmt_infos)
+  Marshal.(to_channel oc (cmt : cmt_infos) [Compression])
 
 let read filename =
 (*  Printf.fprintf stderr "Cmt_format.read %s\n%!" filename; *)