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1 files changed, 96 insertions, 0 deletions

diff --git a/src/boot/llvm/llfinal.ml b/src/boot/llvm/llfinal.ml
new file mode 100644
index 00000000..64ea3d37
--- /dev/null
+++ b/src/boot/llvm/llfinal.ml
@@ -0,0 +1,96 @@
+(*
+ * LLVM ABI-level stuff that needs to happen after modules have been
+ * translated.
+ *)
+
+let finalize_module
+    (llctx:Llvm.llcontext)
+    (llmod:Llvm.llmodule)
+    (abi:Llabi.abi)
+    (asm_glue:Llasm.asm_glue)
+    (exit_task_glue:Llvm.llvalue)
+    (crate_ptr:Llvm.llvalue)
+    : unit =
+  let i32 = Llvm.i32_type llctx in
+
+  (*
+   * Count the number of Rust functions and the number of C functions by
+   * simply (and crudely) testing whether each function in the module begins
+   * with "_rust_".
+   *)
+
+  let (rust_fn_count, c_fn_count) =
+    let count (rust_fn_count, c_fn_count) fn =
+      let begins_with prefix str =
+        let (str_len, prefix_len) =
+          (String.length str, String.length prefix)
+        in
+        prefix_len <= str_len && (String.sub str 0 prefix_len) = prefix
+      in
+      if begins_with "_rust_" (Llvm.value_name fn) then
+        (rust_fn_count + 1, c_fn_count)
+      else
+        (rust_fn_count, c_fn_count + 1)
+    in
+    Llvm.fold_left_functions count (0, 0) llmod
+  in
+
+  let crate_val =
+    let crate_addr = Llvm.const_ptrtoint crate_ptr i32 in
+    let glue_off glue =
+      let addr = Llvm.const_ptrtoint glue i32 in
+        Llvm.const_sub addr crate_addr
+    in
+    let activate_glue_off = glue_off asm_glue.Llasm.asm_activate_glue in
+    let yield_glue_off = glue_off asm_glue.Llasm.asm_yield_glue in
+    let exit_task_glue_off = glue_off exit_task_glue in
+
+    Llvm.const_struct llctx [|
+      Llvm.const_int i32 0;             (* ptrdiff_t image_base_off *)
+      crate_ptr;                        (* uintptr_t self_addr *)
+      Llvm.const_int i32 0;             (* ptrdiff_t debug_abbrev_off *)
+      Llvm.const_int i32 0;             (* size_t debug_abbrev_sz *)
+      Llvm.const_int i32 0;             (* ptrdiff_t debug_info_off *)
+      Llvm.const_int i32 0;             (* size_t debug_info_sz *)
+      activate_glue_off;                (* size_t activate_glue_off *)
+      exit_task_glue_off;               (* size_t main_exit_task_glue_off *)
+      Llvm.const_int i32 0;             (* size_t unwind_glue_off *)
+      yield_glue_off;                   (* size_t yield_glue_off *)
+      Llvm.const_int i32 rust_fn_count; (* int n_rust_syms *)
+      Llvm.const_int i32 c_fn_count;    (* int n_c_syms *)
+      Llvm.const_int i32 0              (* int n_libs *)
+    |]
+  in
+
+  Llvm.set_initializer crate_val crate_ptr;
+
+  (* Define the main function for crt0 to call. *)
+  let main_fn =
+    let main_ty = Llvm.function_type i32 [| i32; i32 |] in
+    Llvm.define_function "main" main_ty llmod
+  in
+  let argc = Llvm.param main_fn 0 in
+  let argv = Llvm.param main_fn 1 in
+  let main_builder = Llvm.builder_at_end llctx (Llvm.entry_block main_fn) in
+  let rust_main_fn =
+    match Llvm.lookup_function "_rust_main" llmod with
+        None -> raise (Failure "no main function found")
+      | Some fn -> fn
+  in
+  let rust_start = abi.Llabi.rust_start in
+  let rust_start_args = [| rust_main_fn; crate_ptr; argc; argv |] in
+    ignore (Llvm.build_call
+              rust_start rust_start_args "start_rust" main_builder);
+    ignore (Llvm.build_ret (Llvm.const_int i32 0) main_builder)
+;;
+
+
+(*
+ * 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:
+ *)
+