From 8e5e66b66cf318722e5b128c1b690fa2d080f1db Mon Sep 17 00:00:00 2001
From: Anders Svensson <anders@erlang.org>
Date: Fri, 12 Sep 2014 16:31:24 +0200
Subject: Fix ?MODULE in preprocessed dictionary forms

By replacing literal diameter_gen_relay atoms in forms extracted from
that module by the name of the module in question. This has been wrong
for some time, but only became noticable when the parent commit started
using ?MODULE as more than a process dictionary key or tag to match on.
In particular, the function dict/1 in diameter_gen.hrl (included by
every dictionary module) can now return ?MODULE, which is (not
surprisingly) expected to be the name of the dictionary module in
question. It wasn't in the case of a module compiled from forms: it was
diameter_gen_relay, since that's the module the forms were extracted
from.

The fix only affects dictionaries compiled from forms, as returned by
diameter_make:codec/2. In particular, dictionaries compiled from Erlang
source returned by this function, or by diameterc(1), are unaffected.
---
 lib/diameter/src/compiler/diameter_codegen.erl | 33 ++++++++++++++++++++++----
 1 file changed, 28 insertions(+), 5 deletions(-)

(limited to 'lib')

diff --git a/lib/diameter/src/compiler/diameter_codegen.erl b/lib/diameter/src/compiler/diameter_codegen.erl
index 5a068c1a25..d91a776321 100644
--- a/lib/diameter/src/compiler/diameter_codegen.erl
+++ b/lib/diameter/src/compiler/diameter_codegen.erl
@@ -132,7 +132,7 @@ gen(parse, ParseD, _Mod) ->
     [?VERSION | ParseD];
 
 gen(forms, ParseD, Mod) ->
-    pp(erl_forms(Mod, ParseD));
+    preprocess(Mod, erl_forms(Mod, ParseD));
 
 gen(hrl, ParseD, Mod) ->
     gen_hrl(Mod, ParseD);
@@ -838,19 +838,19 @@ rec_name(Name, Prefix) ->
     Prefix ++ Name.
 
 %% ===========================================================================
-%% pp/1
+%% preprocess/2
 %%
 %% Preprocess forms as generated by 'forms' option. In particular,
 %% replace the include_lib attributes in generated forms by the
 %% corresponding forms, extracting the latter from an existing
 %% dictionary (diameter_gen_relay). The resulting forms can be
 %% compiled to beam using compile:forms/2 (which does no preprocessing
-%% or it's own; DiY currently appears to be the only way to preprocess
+%% of it's own; DiY currently appears to be the only way to preprocess
 %% a forms list).
 
-pp(Forms) ->
+preprocess(Mod, Forms) ->
     {_, Beam, _} = code:get_object_code(diameter_gen_relay),
-    pp(Forms, abstract_code(Beam)).
+    pp(Forms, remod(Mod, abstract_code(Beam))).
 
 pp(Forms, {ok, Code}) ->
     Files = files(Code, []),
@@ -859,6 +859,25 @@ pp(Forms, {ok, Code}) ->
 pp(Forms, {error, Reason}) ->
     erlang:error({forms, Reason, Forms}).
 
+%% Replace literal diameter_gen_relay atoms in the extracted forms.
+%% ?MODULE for example.
+
+remod(Mod, L)
+  when is_list(L) ->
+    [remod(Mod, T) || T <- L];
+
+remod(Mod, {atom, _, diameter_gen_relay} = T) ->
+    setelement(3, T, Mod);
+
+remod(Mod, T)
+  when is_tuple(T) ->
+    list_to_tuple(remod(Mod, tuple_to_list(T)));
+
+remod(_, T) ->
+    T.
+
+%% Replace include_lib by the corresponding forms.
+
 include({attribute, _, include_lib, Path}, Files) ->
     Inc = filename:basename(Path),
     [{Inc, Forms}] = [T || {F, _} = T <- Files, F == Inc], %% expect one
@@ -867,6 +886,8 @@ include({attribute, _, include_lib, Path}, Files) ->
 include(T, _) ->
     [T].
 
+%% Extract abstract code.
+
 abstract_code(Beam) ->
     case beam_lib:chunks(Beam, [abstract_code]) of
         {ok, {_Mod, [{abstract_code, {_Vsn, Code}}]}} ->
@@ -877,6 +898,8 @@ abstract_code(Beam) ->
             {E, Reason}
     end.
 
+%% Extract filename/forms pairs for included forms.
+
 files([{attribute, _, file, {Path, _}} | T], Acc) ->
     {Body, Rest} = lists:splitwith(fun({attribute, _, file, _}) -> false;
                                       (_) -> true
-- 
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