File 2027-Correct-erlang-is_builtin-3-for-apply-2-and-yield-0.patch of Package erlang
From 696f47b64c8ad5da71cbffd8fecf0f3bae1e7466 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= <bjorn@erlang.org>
Date: Thu, 26 Oct 2017 12:57:24 +0200
Subject: [PATCH] Correct erlang:is_builtin/3 for apply/2 and yield/0
erlang:is_builtin(erlang, M, F) returns false for apply/2 and
yield/0. The documentation for erlang:is_builtin/3 says that it
returns true for BIFs that are implemented in C. apply/2 and
yield/0 are implemented in C (as BEAM instructions), and
therefore the correct return value is true.
Also see a similar argument that was made for apply/3 in the past:
http://erlang.org/pipermail/erlang-bugs/2015-October/005101.html
https://bugs.erlang.org/browse/ERL-500
---
erts/emulator/beam/beam_emu.c | 17 ++++++++++-------
erts/emulator/test/bif_SUITE.erl | 18 ++++++++++++------
lib/tools/test/xref_SUITE.erl | 22 +++++++++++-----------
3 files changed, 33 insertions(+), 24 deletions(-)
diff --git a/erts/emulator/beam/beam_emu.c b/erts/emulator/beam/beam_emu.c
index aa94fbf536..60d0008d8f 100644
--- a/erts/emulator/beam/beam_emu.c
+++ b/erts/emulator/beam/beam_emu.c
@@ -3199,13 +3199,16 @@ erts_is_builtin(Eterm Mod, Eterm Name, int arity)
Export e;
Export* ep;
- if (Mod == am_erlang && Name == am_apply && arity == 3) {
- /*
- * Special case. apply/3 is built-in (implemented in C),
- * but implemented in a different way than all other
- * BIFs.
- */
- return 1;
+ if (Mod == am_erlang) {
+ /*
+ * Special case for built-in functions that are implemented
+ * as instructions as opposed to SNIFs.
+ */
+ if (Name == am_apply && (arity == 2 || arity == 3)) {
+ return 1;
+ } else if (Name == am_yield && arity == 0) {
+ return 1;
+ }
}
e.info.mfa.module = Mod;
diff --git a/erts/emulator/test/bif_SUITE.erl b/erts/emulator/test/bif_SUITE.erl
index 146c37b118..e1b42e5d85 100644
--- a/erts/emulator/test/bif_SUITE.erl
+++ b/erts/emulator/test/bif_SUITE.erl
@@ -781,14 +781,20 @@ is_builtin(_Config) ->
{F,A} <- M:module_info(exports)],
Exp = ordsets:from_list(Exp0),
- %% erlang:apply/3 is considered to be built-in, but is not
- %% implemented as other BIFs.
+ %% Built-ins implemented as special instructions.
+ Instructions = [{erlang,apply,2},{erlang,apply,3},{erlang,yield,0}],
- Builtins0 = [{erlang,apply,3}|erlang:system_info(snifs)],
+ Builtins0 = Instructions ++ erlang:system_info(snifs),
Builtins = ordsets:from_list(Builtins0),
- NotBuiltin = ordsets:subtract(Exp, Builtins),
- _ = [true = erlang:is_builtin(M, F, A) || {M,F,A} <- Builtins],
- _ = [false = erlang:is_builtin(M, F, A) || {M,F,A} <- NotBuiltin],
+
+ Fakes = [{M,F,42} || {M,F,_} <- Instructions],
+ All = ordsets:from_list(Fakes ++ Exp),
+ NotBuiltin = ordsets:subtract(All, Builtins),
+
+ _ = [{true,_} = {erlang:is_builtin(M, F, A),MFA} ||
+ {M,F,A}=MFA <- Builtins],
+ _ = [{false,_} = {erlang:is_builtin(M, F, A),MFA} ||
+ {M,F,A}=MFA <- NotBuiltin],
ok.
diff --git a/lib/tools/test/xref_SUITE.erl b/lib/tools/test/xref_SUITE.erl
index d651cbcfee..018f632948 100644
--- a/lib/tools/test/xref_SUITE.erl
+++ b/lib/tools/test/xref_SUITE.erl
@@ -1112,27 +1112,16 @@ read_expected(Version) ->
{POS7+2,{FF,{erlang,spawn_opt,4}}},
{POS8+1,{FF,{hej,san,1}}},
{POS8+4,{FF,{a,b,1}}},
- {POS8+4,{FF,{erlang,apply,2}}},
- {POS8+5,{FF,{erlang,apply,2}}},
{POS8+6,{FF,{m,f,1}}},
{POS9+1,{FF,{read,bi,0}}},
{POS9+2,{FF,{a,b,1}}},
- {POS9+2,{FF,{erlang,apply,2}}},
- {POS9+3,{FF,{erlang,apply,2}}},
- {POS9+4,{FF,{erlang,apply,2}}},
{POS9+4,{FF,{erlang,not_a_function,1}}},
{POS9+5,{FF,{mod,func,2}}},
{POS9+6,{FF,{erlang,apply,1}}},
- {POS9+7,{FF,{erlang,apply,2}}},
{POS9+7,{FF,{math,add3,1}}},
{POS9+8,{FF,{q,f,1}}},
- {POS10+4,{FF,{erlang,apply,2}}},
{POS10+5,{FF,{mod1,fun1,1}}},
- {POS11+6,{FF,{erlang,apply,2}}},
- {POS12+1,{FF,{erlang,apply,2}}},
- {POS12+4,{FF,{erlang,apply,2}}},
{POS12+5,{FF,{m3,f3,2}}},
- {POS12+7,{FF,{erlang,apply,2}}},
{POS13+1,{FF,{dm,df,1}}},
{POS13+6,{{read,bi,0},{foo,module_info,0}}},
{POS13+7,{{read,bi,0},{read,module_info,0}}},
@@ -1162,15 +1151,26 @@ read_expected(Version) ->
{POS3+3, {FF,{erlang,spawn_link,3}}},
{POS3+4, {FF,{erlang,spawn_link,3}}},
{POS6+4, {FF,{erlang,spawn,3}}},
+ {POS8+4,{FF,{erlang,apply,2}}},
+ {POS8+5,{FF,{erlang,apply,2}}},
{POS8+6,{FF,{erlang,apply,3}}},
{POS8+7,{FF,{erlang,apply,3}}},
{POS9+1,{FF,{erlang,apply,3}}},
+ {POS9+2,{FF,{erlang,apply,2}}},
+ {POS9+3,{FF,{erlang,apply,2}}},
+ {POS9+4,{FF,{erlang,apply,2}}},
{POS9+5,{FF,{erlang,apply,3}}},
+ {POS9+7,{FF,{erlang,apply,2}}},
+ {POS10+4,{FF,{erlang,apply,2}}},
{POS11+1,{FF,{erlang,apply,3}}},
{POS11+2,{FF,{erlang,apply,3}}},
{POS11+3,{FF,{erlang,apply,3}}},
{POS11+4,{FF,{erlang,apply,3}}},
+ {POS11+6,{FF,{erlang,apply,2}}},
+ {POS12+1,{FF,{erlang,apply,2}}},
+ {POS12+4,{FF,{erlang,apply,2}}},
{POS12+5,{FF,{erlang,apply,3}}},
+ {POS12+7,{FF,{erlang,apply,2}}},
{POS12+8,{FF,{erlang,apply,3}}},
{POS13+5, {{read,bi,0},{erlang,length,1}}},
{POS14+3, {{read,bi,0},{erlang,length,1}}}],
--
2.14.3
