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, 13 insertions, 9 deletions

diff --git a/lib/compiler/src/v3_core.erl b/lib/compiler/src/v3_core.erl
index 8b04969b05..4ac2196d79 100644
--- a/lib/compiler/src/v3_core.erl
+++ b/lib/compiler/src/v3_core.erl
@@ -1542,17 +1542,21 @@ new_vars_1(N, Anno, St0, Vs) when N > 0 ->
 new_vars_1(0, _, St, Vs) -> {Vs,St}.
 
 function_clause(Ps, Name) ->
-    fail_clause(Ps, c_tuple([#c_literal{anno=[{name,Name}],
-					val=function_clause}|Ps])).
-function_clause(Ps, Anno, Name) ->
-    fail_clause(Ps, ann_c_tuple(Anno,
-				[#c_literal{anno=[{name,Name}],
-					    val=function_clause}|Ps])).
-
-fail_clause(Pats, A) ->
+    function_clause(Ps, [], Name).
+
+function_clause(Ps, LineAnno, Name) ->
+    FcAnno = [{function_name,Name}],
+    fail_clause(Ps, FcAnno,
+		ann_c_tuple(LineAnno, [#c_literal{val=function_clause}|Ps])).
+
+fail_clause(Pats, Arg) ->
+    fail_clause(Pats, [], Arg).
+
+fail_clause(Pats, Anno, Arg) ->
     #iclause{anno=#a{anno=[compiler_generated]},
 	     pats=Pats,guard=[],
-	     body=[#iprimop{anno=#a{},name=#c_literal{val=match_fail},args=[A]}]}.
+	     body=[#iprimop{anno=#a{anno=Anno},name=#c_literal{val=match_fail},
+			    args=[Arg]}]}.
 
 ubody(B, St) -> uexpr(B, [], St).