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, 4 insertions, 8 deletions

diff --git a/lib/compiler/src/sys_core_inline.erl b/lib/compiler/src/sys_core_inline.erl
index 06696e5950..c644b9e015 100644
--- a/lib/compiler/src/sys_core_inline.erl
+++ b/lib/compiler/src/sys_core_inline.erl
@@ -41,11 +41,9 @@
 
 -module(sys_core_inline).
 
-%%-compile({inline,{match_fail_fun,0}}).
-
 -export([module/2]).
 
--import(lists, [member/2,map/2,foldl/3,mapfoldl/3]).
+-import(lists, [member/2,map/2,foldl/3,mapfoldl/3,keydelete/3]).
 
 -include("core_parse.hrl").
 
@@ -178,11 +176,9 @@ weight_func(_Core, Acc) -> Acc + 1.
 %% function_clause match_fail (if they have one).
 
 match_fail_fun() ->
-    fun (#c_primop{name=#c_literal{val=match_fail},
-		   args=[#c_tuple{es=[#c_literal{val=function_clause}|As]}]}=P) ->
-	    Fail = #c_tuple{es=[#c_literal{val=case_clause},
-				#c_tuple{es=As}]},
-	    P#c_primop{args=[Fail]};
+    fun (#c_primop{anno=Anno0,name=#c_literal{val=match_fail}}=P) ->
+	    Anno = keydelete(function_name, 1, Anno0),
+	    P#c_primop{anno=Anno};
 	(Other) -> Other
     end.