adds the call destination names in the assembly output

This is a simple quality of life update that should be done many years
ago. This change adds printing the call destination name in the
assembly output, much like objdump does, e.g.,
```
c23e: e8 35 7c ff ff            callq -0x83cb # <malloc>
```

The commit also publishes the `Symtab.callee` function that gives this
information.

lib/bap/bap.mli

@@ -7845,6 +7845,13 @@ module Std : sig
     (** [span fn] returns a memory map of a region occupied by a
         function [fn] *)
     val span : fn -> unit memmap
+
+    (** [explicit_callee symtab address] returns a callee which is
+        called from a  block with the given [address].
+
+        @since 2.5.0
+    *)
+    val callee : t -> addr -> string option
   end
 
   type lifter = mem -> Disasm_expert.Basic.full_insn -> bil Or_error.t

lib/bap_disasm/bap_disasm_symtab.ml

@@ -120,6 +120,10 @@ let insert_call ?(implicit=false) symtab block data =
 
 let explicit_callee {ecalls} = Map.find ecalls
 let implicit_callee {icalls} = Map.find icalls
+let callee tab src = match explicit_callee tab src with
+  | Some dst -> Some dst
+  | None -> implicit_callee tab src
+
 
 
 let (<--) = fun g f -> match g with

lib/bap_disasm/bap_disasm_symtab.mli

@@ -61,3 +61,5 @@ val explicit_callee : t -> addr -> string option
 (** [implicit_callee symtab address] returns a callee which is
     implicitly called from a block with the given [address]. *)
 val implicit_callee : t -> addr -> string option
+
+val callee : t -> addr -> string option

plugins/print/print_main.ml

@@ -369,6 +369,7 @@ let section_name memory start =
   function Some name -> name
          | None -> Format.asprintf ".section@%a" Addr.pp start
 
+let same_name x y = String.(Insn.name x = Insn.name y)
 
 let print_disasm pp_insn patterns ppf proj =
   let memory = Project.memory proj in
@@ -389,19 +390,22 @@ let print_disasm pp_insn patterns ppf proj =
             sorted_blocks (Graphs.Cfg.nodes cfg) |> Seq.iter ~f:(fun blk ->
                 let mem = Block.memory blk in
                 fprintf ppf "%a:@\n" pp_addr (Memory.min_addr mem);
-                Block.insns blk |> List.iter ~f:(pp_insn ppf))));
+                Block.insns blk |> List.iter ~f:(pp_insn syms blk ppf))));
   pp_close_tbox ppf ()
 
-let pp_bil fmt ppf (mem,insn) =
+let pp_bil fmt _ _ ppf (mem,insn) =
   let pp_bil ppf = Bil.Io.print ~fmt ppf in
   let addr = Memory.min_addr mem in
   fprintf ppf "%a: %s@\n%a@\n" pp_addr addr (Insn.asm insn)
     pp_bil (Insn.bil insn)
 
-let pp_insn fmt ppf (mem,insn) =
+let pp_insn fmt tab blk ppf (mem,insn) =
   Memory.pp ppf mem;
   pp_print_tab ppf ()  [@ocaml.warning "-3"];
   Insn.Io.print ~fmt ppf insn;
+  if same_name insn (Block.terminator blk)
+  then Option.iter (Symtab.callee tab (Block.addr blk))
+      ~f:(fprintf ppf " # <%s>");
   fprintf ppf "@\n"
 
 let pp_knowledge ppf _ =