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1 files changed, 192 insertions, 0 deletions

diff --git a/src/boot/llvm/llasm.ml b/src/boot/llvm/llasm.ml
new file mode 100644
index 00000000..56448b07
--- /dev/null
+++ b/src/boot/llvm/llasm.ml
@@ -0,0 +1,192 @@
+(*
+ * machine-specific assembler routines.
+ *)
+
+open Common;;
+
+type asm_glue =
+    {
+      asm_activate_glue : Llvm.llvalue;
+      asm_yield_glue : Llvm.llvalue;
+      asm_upcall_glues : Llvm.llvalue array;
+    }
+;;
+
+let n_upcall_glues = 7
+;;
+
+(* x86-specific asm. *)
+
+let x86_glue
+  (llctx:Llvm.llcontext)
+  (llmod:Llvm.llmodule)
+  (abi:Llabi.abi)
+  (sess:Session.sess)
+  : asm_glue =
+  let (prefix,align) =
+    match sess.Session.sess_targ with
+        Linux_x86_elf
+      | Win32_x86_pe -> ("",4)
+      | MacOS_x86_macho -> ("_", 16)
+  in
+  let save_callee_saves =
+    ["pushl %ebp";
+     "pushl %edi";
+     "pushl %esi";
+     "pushl %ebx";]
+  in
+  let restore_callee_saves =
+    ["popl  %ebx";
+     "popl  %esi";
+     "popl  %edi";
+     "popl  %ebp";]
+  in
+  let load_esp_from_rust_sp    = ["movl  12(%edx), %esp"] in
+  let load_esp_from_runtime_sp = ["movl   8(%edx), %esp"] in
+  let store_esp_to_rust_sp     = ["movl  %esp, 12(%edx)"] in
+  let store_esp_to_runtime_sp  = ["movl  %esp,  8(%edx)"] in
+  let list_init i f = (Array.to_list (Array.init i f)) in
+  let list_init_concat i f = List.concat (list_init i f) in
+
+  let glue =
+    [
+      ("rust_activate_glue",
+       String.concat "\n\t"
+         (["movl  4(%esp), %edx    # edx = rust_task"]
+          @ save_callee_saves
+          @ store_esp_to_runtime_sp
+          @ load_esp_from_rust_sp
+            (* 
+             * This 'add' instruction is a bit surprising.
+             * See lengthy comment in boot/be/x86.ml activate_glue.
+             *)
+          @ ["addl  $20, 12(%edx)"]
+          @ restore_callee_saves
+          @ ["ret"]));
+
+      ("rust_yield_glue",
+       String.concat "\n\t"
+
+         (["movl  0(%esp), %edx    # edx = rust_task"]
+          @ load_esp_from_rust_sp
+          @ save_callee_saves
+          @ store_esp_to_rust_sp
+          @ load_esp_from_runtime_sp
+          @ restore_callee_saves
+          @ ["ret"]))
+    ]
+    @ list_init n_upcall_glues
+      begin
+        fun i ->
+          (* 
+           * 0, 4, 8, 12 are callee-saves
+           * 16 is retpc
+           * 20 is taskptr
+           * 24 is callee
+           * 28 .. (7+i) * 4 are args
+           *)
+
+          ((Printf.sprintf "rust_upcall_%d" i),
+           String.concat "\n\t"
+             (save_callee_saves
+              @ ["movl  %esp, %ebp     # ebp = rust_sp";
+                 "movl  20(%esp), %edx # edx = rust_task"]
+              @ store_esp_to_rust_sp
+              @ load_esp_from_runtime_sp
+              @ [Printf.sprintf
+                   "subl  $%d, %%esp   # esp -= args" ((i+1)*4);
+                 "andl  $~0xf, %esp    # align esp down";
+                 "movl  %edx, (%esp)   # arg[0] = rust_task "]
+
+              @ (list_init_concat i
+                   begin
+                     fun j ->
+                       [ Printf.sprintf "movl  %d(%%ebp),%%edx" ((j+7)*4);
+                         Printf.sprintf "movl  %%edx,%d(%%esp)" ((j+1)*4) ]
+                   end)
+
+              @ ["movl  24(%ebp), %edx # edx = callee";
+                 "call  *%edx          # call *%edx";
+                 "movl  20(%ebp), %edx # edx = rust_task"]
+              @ load_esp_from_rust_sp
+              @ restore_callee_saves
+              @ ["ret"]))
+      end
+  in
+
+  let _ =
+    Llvm.set_module_inline_asm llmod
+      begin
+        String.concat "\n"
+          begin
+            List.map
+              begin
+                fun (sym,asm) ->
+                  Printf.sprintf
+                    "\t.globl %s%s\n\t.balign %d\n%s%s:\n\t%s"
+                    prefix sym align prefix sym asm
+              end
+              glue
+          end
+      end
+  in
+
+  let decl_cdecl_fn name out_ty arg_tys =
+    let ty = Llvm.function_type out_ty arg_tys in
+    let fn = Llvm.declare_function name ty llmod in
+      Llvm.set_function_call_conv Llvm.CallConv.c fn;
+      fn
+  in
+
+  let decl_glue s =
+    let task_ptr_ty = Llvm.pointer_type abi.Llabi.task_ty in
+    let void_ty = Llvm.void_type llctx in
+      decl_cdecl_fn s void_ty [| task_ptr_ty |]
+  in
+
+  let decl_upcall n =
+    let task_ptr_ty = Llvm.pointer_type abi.Llabi.task_ty in
+    let word_ty = abi.Llabi.word_ty in
+    let callee_ty = word_ty in
+    let args_ty =
+      Array.append
+        [| task_ptr_ty; callee_ty |]
+        (Array.init n (fun _ -> word_ty))
+    in
+    let name = Printf.sprintf "rust_upcall_%d" n in
+      decl_cdecl_fn name word_ty args_ty
+  in
+    {
+      asm_activate_glue = decl_glue "rust_activate_glue";
+      asm_yield_glue = decl_glue "rust_yield_glue";
+      asm_upcall_glues = Array.init n_upcall_glues decl_upcall;
+    }
+;;
+
+(* x64-specific asm. *)
+(* arm-specific asm. *)
+(* ... *)
+
+
+let get_glue
+  (llctx:Llvm.llcontext)
+  (llmod:Llvm.llmodule)
+  (abi:Llabi.abi)
+  (sess:Session.sess)
+  : asm_glue =
+  match sess.Session.sess_targ with
+      Linux_x86_elf
+    | Win32_x86_pe
+    | MacOS_x86_macho ->
+        x86_glue llctx llmod abi sess
+;;
+
+
+(*
+ * Local Variables:
+ * fill-column: 78;
+ * indent-tabs-mode: nil
+ * buffer-file-coding-system: utf-8-unix
+ * compile-command: "make -k -C ../.. 2>&1 | sed -e 's/\\/x\\//x:\\//g'";
+ * End:
+ *)