Remove flambda-backend copies of Closure, Flambda 1, Clambda, Cmmgen, etc.

.github/workflows/build.yml

@@ -76,11 +76,11 @@ jobs:
             check_arch: true
 
           - name: build_upstream_closure
-            config: --enable-middle-end=closure
+            config: --enable-middle-end=upstream-closure
             os: ubuntu-20.04
 
           - name: build_upstream_closure_runtime5
-            config: --enable-middle-end=closure --enable-runtime5
+            config: --enable-middle-end=upstream-closure --enable-runtime5
             os: ubuntu-20.04
             expected_fail: true
 

.github/workflows/ocamlformat.yml

@@ -40,7 +40,7 @@ jobs:
       run: |
         ./configure \
           --prefix=$GITHUB_WORKSPACE/_install \
-          --enable-middle-end=closure \
+          --enable-middle-end=flambda2 \
           --with-dune=/bin/false
 
     - name: Check formatting of Flambda 2 and Cfg code

README.md

@@ -37,10 +37,8 @@ The Flambda backend tree has to be configured before building.  The configure sc
 in; you have to run `autoconf`.  For example:
 ```
 $ autoconf
-$ ./configure --prefix=/path/to/install/dir --enable-middle-end=closure
+$ ./configure --prefix=/path/to/install/dir
 ```
-You can also specify `--enable-middle-end=flambda` or `--enable-middle-end=flambda2`.  (The Flambda 2
-compiler is not yet ready for production use.)
 
 ## Building and installing
 

backend/asmgen.ml

@@ -471,14 +471,6 @@ let end_gen_implementation unix ?toplevel ~ppf_dump ~sourcefile make_cmm =
           !Translmod.primitive_declarations));
   emit_end_assembly sourcefile ()
 
-type middle_end =
-     backend:(module Backend_intf.S)
-  -> filename:string
-  -> prefixname:string
-  -> ppf_dump:Format.formatter
-  -> Lambda.program
-  -> Clambda.with_constants
-
 type direct_to_cmm =
      ppf_dump:Format.formatter
   -> prefixname:string
@@ -487,10 +479,6 @@ type direct_to_cmm =
   -> Cmm.phrase list
 
 type pipeline =
-  | Via_clambda of {
-      backend : (module Backend_intf.S);
-      middle_end : middle_end;
-    }
   | Direct_to_cmm of direct_to_cmm
 
 let asm_filename output_prefix =
@@ -508,12 +496,6 @@ let compile_implementation unix ?toplevel ~pipeline
       Compilation_unit.Set.iter Compilenv.require_global
         program.required_globals;
       match pipeline with
-      | Via_clambda { middle_end; backend; } ->
-        let clambda_with_constants =
-          middle_end ~backend ~filename ~prefixname ~ppf_dump program
-        in
-        end_gen_implementation unix ?toplevel ~ppf_dump ~sourcefile:filename
-          (fun () -> Profile.record "cmm" Cmmgen.compunit clambda_with_constants)
       | Direct_to_cmm direct_to_cmm ->
         let cmm_phrases =
           direct_to_cmm ~ppf_dump ~prefixname ~filename program

backend/asmgen.mli

@@ -15,15 +15,6 @@
 
 (** From Lambda to assembly code *)
 
-(** The type of converters from Lambda to Clambda. *)
-type middle_end =
-     backend:(module Backend_intf.S)
-  -> filename:string
-  -> prefixname:string
-  -> ppf_dump:Format.formatter
-  -> Lambda.program
-  -> Clambda.with_constants
-
 (** The type of converters straight from Lambda to Cmm. This is how Flambda 2
     operates. *)
 type direct_to_cmm =
@@ -33,12 +24,8 @@ type direct_to_cmm =
   -> Lambda.program
   -> Cmm.phrase list
 
-(** The ways to get from Lambda to Cmm. *)
+(** The one true way to get from Lambda to Cmm. *)
 type pipeline =
-  | Via_clambda of {
-      backend : (module Backend_intf.S);
-      middle_end : middle_end;
-    }
   | Direct_to_cmm of direct_to_cmm
 
 (** Compile an implementation from Lambda using the given middle end. *)

backend/asmlibrarian.ml

@@ -27,12 +27,7 @@ type error =
 exception Error of error
 
 let default_ui_export_info =
-  if Config.flambda then
-    Cmx_format.Flambda1 Export_info.empty
-  else if Config.flambda2 then
-    Cmx_format.Flambda2 None
-  else
-    Cmx_format.Clambda Clambda.Value_unknown
+  Cmx_format.Flambda2 None
 
 let read_info name =
   let filename =

backend/asmlink.ml

@@ -359,7 +359,8 @@ let make_startup_file unix ~ppf_dump ~sourcefile_for_dwarf genfns units =
     List.flatten (List.map (fun u -> u.defines) units) in
   List.iter compile_phrase (Cmm_helpers.entry_point name_list);
   List.iter compile_phrase
-    (Cmm_helpers.emit_preallocated_blocks [] (* add gc_roots (for dynlink) *)
+    (* Emit the GC roots table, for dynlink. *)
+    (Cmm_helpers.emit_gc_roots_table ~symbols:[]
       (Generic_fns.compile ~shared:false genfns));
   Array.iteri
     (fun i name -> compile_phrase (Cmm_helpers.predef_exception i name))
@@ -404,7 +405,7 @@ let make_shared_startup_file unix ~ppf_dump ~sourcefile_for_dwarf genfns units =
     sourcefile_for_dwarf;
   Emit.begin_assembly unix;
   List.iter compile_phrase
-    (Cmm_helpers.emit_preallocated_blocks [] (* add gc_roots (for dynlink) *)
+    (Cmm_helpers.emit_gc_roots_table ~symbols:[]
       (Generic_fns.compile ~shared:true genfns));
   let dynunits = List.map (fun u -> Option.get u.dynunit) units in
   compile_phrase (Cmm_helpers.plugin_header dynunits);

backend/asmpackager.ml

@@ -92,7 +92,7 @@ type flambda2 =
   Cmm.phrase list
 
 let make_package_object unix ~ppf_dump members targetobj targetname coercion
-      ~backend ~(flambda2 : flambda2) =
+      ~(flambda2 : flambda2) =
   Profile.record_call (Printf.sprintf "pack(%s)" targetname) (fun () ->
     let objtemp =
       if !Clflags.keep_asm_file
@@ -137,14 +137,7 @@ let make_package_object unix ~ppf_dump members targetobj targetname coercion
       }
     in
     let pipeline : Asmgen.pipeline =
-      if Config.flambda2 then
-        Direct_to_cmm (flambda2 ~keep_symbol_tables:true)
-      else
-        let middle_end =
-          if Config.flambda then Flambda_middle_end.lambda_to_clambda
-          else Closure_middle_end.lambda_to_clambda
-        in
-        Via_clambda { middle_end; backend }
+      Direct_to_cmm (flambda2 ~keep_symbol_tables:true)
     in
     Asmgen.compile_implementation ~pipeline unix
       ~filename:targetname
@@ -167,24 +160,8 @@ let make_package_object unix ~ppf_dump members targetobj targetname coercion
 let get_export_info_flambda2 ui : Flambda2_cmx.Flambda_cmx_format.t option =
   assert(Config.flambda2);
   match ui.ui_export_info with
-  | Clambda _ -> assert false
-  | Flambda1 _ -> assert false
   | Flambda2 info -> info
 
-let get_export_info_flambda1 ui : Export_info.t =
-  assert(Config.flambda);
-  match ui.ui_export_info with
-  | Clambda _ -> assert false
-  | Flambda1 (info : Export_info.t) -> info
-  | Flambda2 _ -> assert false
-
-let get_approx ui : Clambda.value_approximation =
-  assert(not (Config.flambda || Config.flambda2));
-  match ui.ui_export_info with
-  | Clambda info -> info
-  | Flambda1 _ -> assert false
-  | Flambda2 _ -> assert false
-
 let build_package_cmx members cmxfile =
   let unit_names =
     List.map (fun m -> m.pm_name) members in
@@ -203,26 +180,14 @@ let build_package_cmx members cmxfile =
       members [] in
   let ui = Compilenv.current_unit_infos() in
   let ui_export_info =
-    if Config.flambda then
-      let ui_export_info =
-        List.fold_left (fun acc info ->
-            Export_info.merge acc
-              (get_export_info_flambda1 info))
-          (get_export_info_flambda1 ui)
-          units
-      in
-      Flambda1 ui_export_info
-    else if Config.flambda2 then
-      let flambda_export_info =
-        List.fold_left (fun acc info ->
-            Flambda2_cmx.Flambda_cmx_format.merge
-              (get_export_info_flambda2 info) acc)
-          (get_export_info_flambda2 ui)
-          units
-      in
-      Flambda2 flambda_export_info
-    else
-      Clambda (get_approx ui)
+    let flambda_export_info =
+      List.fold_left (fun acc info ->
+          Flambda2_cmx.Flambda_cmx_format.merge
+            (get_export_info_flambda2 info) acc)
+        (get_export_info_flambda2 ui)
+        units
+    in
+    Flambda2 flambda_export_info
   in
   let ui_checks = Checks.create () in
   List.iter (fun info -> Checks.merge info.ui_checks ~into:ui_checks) units;
@@ -255,7 +220,7 @@ let build_package_cmx members cmxfile =
 (* Make the .cmx and the .o for the package *)
 
 let package_object_files unix ~ppf_dump files targetcmx
-                         targetobj targetname coercion ~backend ~flambda2 =
+                         targetobj targetname coercion ~flambda2 =
   let pack_path =
     let for_pack_prefix = CU.Prefix.from_clflags () in
     let name = targetname |> CU.Name.of_string in
@@ -264,13 +229,12 @@ let package_object_files unix ~ppf_dump files targetcmx
   let members = map_left_right (read_member_info pack_path) files in
   check_units members;
   make_package_object unix ~ppf_dump members targetobj targetname coercion
-    ~backend ~flambda2;
+    ~flambda2;
   build_package_cmx members targetcmx
 
 (* The entry point *)
 
-let package_files unix ~ppf_dump initial_env files targetcmx ~backend
-      ~flambda2 =
+let package_files unix ~ppf_dump initial_env files targetcmx ~flambda2 =
   let files =
     List.map
       (fun f ->
@@ -293,7 +257,7 @@ let package_files unix ~ppf_dump initial_env files targetcmx ~backend
       let coercion =
         Typemod.package_units initial_env files targetcmi comp_unit in
       package_object_files unix ~ppf_dump files targetcmx targetobj targetname
-        coercion ~backend ~flambda2
+        coercion ~flambda2
     )
     ~exceptionally:(fun () -> remove_file targetcmx; remove_file targetobj)
 

backend/asmpackager.mli

@@ -22,7 +22,6 @@ val package_files
   -> Env.t
   -> string list
   -> string
-  -> backend:(module Backend_intf.S)
   -> flambda2:(
     ppf_dump:Format.formatter ->
     prefixname:string ->