From 34902b58f0f4afc99e564f73de6e02d85200e0ca Mon Sep 17 00:00:00 2001
From: Tom Barthe <tom.barthe@ens-paris-saclay.fr>
Date: Tue, 22 Dec 2020 00:03:08 +0100
Subject: [PATCH] Add basic copy functions

Warning: These functions are not yet atomic.
---
 compiler/obc/c/async_backend.mli |  8 ++++++++
 compiler/obc/c/async_posix.ml    | 32 ++++++++++++++++++++++++++++++++
 compiler/obc/c/cgen.ml           |  9 ++++++++-
 3 files changed, 48 insertions(+), 1 deletion(-)
 create mode 100644 compiler/obc/c/async_backend.mli
 create mode 100644 compiler/obc/c/async_posix.ml

diff --git a/compiler/obc/c/async_backend.mli b/compiler/obc/c/async_backend.mli
new file mode 100644
index 0000000..90ce29b
--- /dev/null
+++ b/compiler/obc/c/async_backend.mli
@@ -0,0 +1,8 @@
+open C
+open Obc
+
+module type AsyncBackend =
+sig
+  val gen_copy_func_in : class_def -> cdef
+  val gen_copy_func_out : class_def -> cdef
+end
diff --git a/compiler/obc/c/async_posix.ml b/compiler/obc/c/async_posix.ml
new file mode 100644
index 0000000..a9d4f69
--- /dev/null
+++ b/compiler/obc/c/async_posix.ml
@@ -0,0 +1,32 @@
+open Names
+open C
+open Obc
+open Async_backend
+
+module PosixBackend : AsyncBackend =
+struct
+  let qn_append q suffix =
+    { qual = q.qual; name = q.name ^ suffix }
+
+  (* FIXME(Arduino): don't do a shallow copy *)
+  (* FIXME(Arduino): add a mutex… *)
+  let gen_copy_func cd suffix =
+    let func_name = (cname_of_qn cd.cd_name) ^ "_copy" ^ suffix in
+    (* TODO(Arduino): add const qualifier *)
+    let arg_ty = Cty_ptr (Cty_id (qn_append cd.cd_name suffix)) in
+    let sizeof = Cfun_call ("sizeof", [Cderef (Cvar "src")]) in
+    let memcpy = Cfun_call ("memcpy", [Cvar "dest"; Cvar "src"; sizeof]) in
+    Cfundef {
+      C.f_name = func_name;
+      f_retty = Cty_void;
+      f_args = [("dest", arg_ty); ("src", arg_ty)];
+      f_body = {
+       var_decls = [];
+       block_body = [Csexpr memcpy] }
+    }
+
+  let gen_copy_func_in cd = gen_copy_func cd "_in"
+
+  let gen_copy_func_out cd = gen_copy_func cd "_out"
+
+end
diff --git a/compiler/obc/c/cgen.ml b/compiler/obc/c/cgen.ml
index 7be6e8d..03cf0cd 100644
--- a/compiler/obc/c/cgen.ml
+++ b/compiler/obc/c/cgen.ml
@@ -34,6 +34,7 @@ open Idents
 open Obc
 open Obc_utils
 open Types
+open Async_posix
 
 open Modules
 open Signature
@@ -801,13 +802,19 @@ let cdefs_and_cdecls_of_class_def cd =
   let out_struct_decl = out_decl_of_class_def cd in
   let step_fun_def = fun_def_of_step_fun cd.cd_name
     cd.cd_objs cd.cd_mems cd.cd_objs step_m in
+  (* TODO(Arduino): let the user choose the backend they want *)
+  let copy_in_def = PosixBackend.gen_copy_func_in cd in
+  let copy_out_def = PosixBackend.gen_copy_func_out cd in
   (* C function for resetting our memory structure. *)
   let reset_fun_def = reset_fun_def_of_class_def cd in
   let res_fun_decl = cdecl_of_cfundef reset_fun_def in
   let step_fun_decl = cdecl_of_cfundef step_fun_def in
+  let copy_in_decl = cdecl_of_cfundef copy_in_def in
+  let copy_out_decl = cdecl_of_cfundef copy_out_def in
   let (decls, defs) =
     if is_stateful cd.cd_name then
-      ([res_fun_decl; step_fun_decl], [reset_fun_def; step_fun_def])
+      ([res_fun_decl; step_fun_decl; copy_in_decl; copy_out_decl],
+       [reset_fun_def; step_fun_def; copy_in_def; copy_out_def])
     else
       ([step_fun_decl], [step_fun_def]) in