Consistently rewrite an inlined function_clause exception to case_clause

A function_clause exception is generated by jumping to a func_info/3
instruction at the beginning of the function. The x registers are
assumed to contain the arguments for the function. That means
that a func_info/3 instruction copied from another function
(or even from the same function if not at the top level) will
not work, so it must be replaced with an instruction that
generates a case_clause exception.

In Core Erlang, a func_info/3 instruction is represented as
a the primop match_fail({function_clause,Arg1,...ArgN}).

The current mechanism that is supposed to replace the
primop match_fail(function_clause) with match_fail(case_clause)
will fail to do that in the following circumstances:

1. If the inliner has inlined a function into itself.
Fix that by having the inliner clear the function_name annotations
on all match_fail primops in functions that are inlined. (To simplify
doing that, the annotation is now on the primop node itself and not on
the 'function_clause' atom inside it.)

2. If the inliner has rewritten the tuple node in the primop node
to a literal (when inlining a function call with literal arguments),
v3_kernel would not recognize the match_fail(function_clause) primop
and would not rewrite it. Fix it by making v3_kernel smarter.

Also simplify the "old" inliner (sys_core_inline) to only clear
the function_name annotations instead of rewriting function_clause
execptions to case_clause execptions itself.

1 files changed, 27 insertions, 5 deletions

diff --git a/lib/compiler/src/cerl_inline.erl b/lib/compiler/src/cerl_inline.erl
index 191efa3032..f4eaa17e72 100644
--- a/lib/compiler/src/cerl_inline.erl
+++ b/lib/compiler/src/cerl_inline.erl
@@ -1429,17 +1429,26 @@ inline(E, #app{opnds = Opnds, ctxt = Ctxt, loc = L}, Ren, Env, S) ->
 	    {E, S};
        true ->
 	    %% Create local bindings for the parameters to their
-	    %% respective operand structures from the app-structure, and
-	    %% visit the body in the context saved in the structure.
+	    %% respective operand structures from the app-structure.
 	    {Rs, Ren1, Env1, S1} = bind_locals(Vs, Opnds, Ren, Env, S),
-	    {E1, S2} = i(fun_body(E), Ctxt, Ren1, Env1, S1),
+
+	    %% function_clause exceptions that have been inlined
+	    %% into another function (or even into the same function)
+	    %% will not work properly. The v3_kernel pass will
+	    %% take care of it, but we will need to help it by
+	    %% removing any function_name annotations on match_fail
+	    %% primops that we inline.
+	    E1 = kill_function_name_anns(fun_body(E)),
+
+	    %% Visit the body in the context saved in the structure.
+	    {E2, S2} = i(E1, Ctxt, Ren1, Env1, S1),
 
 	    %% Create necessary bindings and/or set flags.
-	    {E2, S3} = make_let_bindings(Rs, E1, S2),
+	    {E3, S3} = make_let_bindings(Rs, E2, S2),
 
 	    %% Lastly, flag the application as inlined, since the inlining
 	    %% attempt was not aborted before we reached this point.
-	    {E2, st__set_app_inlined(L, S3)}
+	    {E3, st__set_app_inlined(L, S3)}
     end.
 
 %% For the (possibly renamed) argument variables to an inlined call,
@@ -2370,6 +2379,19 @@ kill_id_anns([A | As]) ->
 kill_id_anns([]) ->
     [].
 
+kill_function_name_anns(Body) ->
+    F = fun(P) ->
+		case type(P) of
+		    primop ->
+			Ann = get_ann(P),
+			Ann1 = lists:keydelete(function_name, 1, Ann),
+			set_ann(P, Ann1);
+		    _ ->
+			P
+		end
+	end,
+    cerl_trees:map(F, Body).
+
 
 %% =====================================================================
 %% General utilities