implements eval-cond via jumping

The `eval-cond` signal is less powerfull that its the same named `eval-cond` observation (as it is not fired from the Lisp code), so we should either deprecate it or even remove it (to prevent confusion between singal and observation that have same meaning but different semantics). With that said, the semantics of `eval-cond` is the same as it was befor 2.1.0 (i.e., starting from 1.5 to 2.0 inclusive), it has changed only in 2.1.0 and now we are rolling back it again. The future of this signal is unclear. Possible we will be able to enable it in the 2.1.0 semantics by enabling two modes of execution of the Primus code - analysis and modelling, but this requires a lot of effort and many not work at the end, so it might be that we will remove this signal at all from Primus Lisp interface in 2.2.0.
BinaryAnalysisPlatform · Jun 22, 2020 · 4308304 · 4308304
1 parent 5cecd09
commit 4308304
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diff --git a/lib/bap_primus/bap_primus_lisp.ml b/lib/bap_primus/bap_primus_lisp.ml
@@ -36,7 +36,7 @@ type bindings = {
 type state = {
   program : Lisp.Program.t;
   typeenv : Lisp.Program.Type.env;
-  signals : subscription String.Map.t;
+  signals : subscription list String.Map.t;
   width : int;
   env : bindings;
   cur : Id.t;
@@ -785,7 +785,7 @@ module Make(Machine : Machine) = struct
         proj x >>= Self.eval_signal name) >>= fun sub ->
     Machine.Local.update state ~f:(fun s -> {
           s with program = Lisp.Program.add s.program signal r;
-                 signals = Map.add_exn s.signals name sub;
+                 signals = Map.add_multi s.signals name sub;
         })
 
 
@@ -822,7 +822,7 @@ module Make(Machine : Machine) = struct
     let useless_subscriptions =
       Map.fold s.signals ~init:[] ~f:(fun ~key:name ~data:sub subs ->
           if Set.mem known_methods name then subs
-          else sub::subs) in
+          else List.rev_append sub @@ subs) in
     Machine.List.iter useless_subscriptions ~f:Machine.Observation.cancel
 
 

diff --git a/plugins/primus_lisp/primus_lisp_main.ml b/plugins/primus_lisp/primus_lisp_main.ml
@@ -101,8 +101,6 @@ module Signals(Machine : Primus.Machine.S) = struct
           {|(written V X) is emitted when X is written to V|};
         signal pc_change word one Type.(one int)
           {|(pc-change PC) is emitted when PC is updated|};
-        signal eval_cond value one Type.(one bool)
-          {|(eval-cond V) is emitted after evaluating a conditional to V|};
         signal jumping (value,value) pair Type.(tuple [bool; int])
           {|(jumping C D) is emitted before jump to D occurs under the
           condition C|};
@@ -133,6 +131,9 @@ module Signals(Machine : Primus.Machine.S) = struct
           The machine is in the resticted mode in the body of the
           methods."
           ~params:Type.unit;
+        Lisp.signal jumping (fun (cnd,_) -> value cnd >>| List.return)
+          ~doc:{|(eval-cond V) is emitted after evaluating a conditional to V|}
+          ~params:Type.(one bool);
       ]
 end