From 39c04c516bf728f93759ad50eb4ac2cf37727d2c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jos=C3=A9=20Valim?= <jose.valim@plataformatec.com.br>
Date: Mon, 1 Oct 2018 13:24:11 +0200
Subject: Introduce the no_spawn_compiler_process option

By default, all code is compiled in a separate process
which is terminated at the end of compilation. However,
some tools, like Dialyzer or compilers for other BEAM languages,
may already manage their own worker processes and spawning
an extra process may slow the compilation down.
In such scenarios, you can pass this option to stop the
compiler from spawning an additional process.

This generalizes commit 657760e18087b0cdbaecc5e96e46f6f66bc9497a.
---
 lib/compiler/doc/src/compile.xml    | 11 +++++++++++
 lib/compiler/src/compile.erl        |  7 +++++--
 lib/dialyzer/src/dialyzer_utils.erl |  2 +-
 3 files changed, 17 insertions(+), 3 deletions(-)

(limited to 'lib')

diff --git a/lib/compiler/doc/src/compile.xml b/lib/compiler/doc/src/compile.xml
index 1a71c83521..f64986d55c 100644
--- a/lib/compiler/doc/src/compile.xml
+++ b/lib/compiler/doc/src/compile.xml
@@ -415,6 +415,17 @@ module.beam: module.erl \
               is not documented, and can change between releases.</p>
           </item>
 
+          <tag><c>no_spawn_compiler_process</c></tag>
+          <item>
+            <p>By default, all code is compiled in a separate process
+              which is terminated at the end of compilation. However,
+              some tools, like Dialyzer or compilers for other BEAM languages,
+              may already manage their own worker processes and spawning
+              an extra process may slow the compilation down.
+              In such scenarios, you can pass this option to stop the
+              compiler from spawning an additional process.</p>
+          </item>
+
           <tag><c>no_strict_record_tests</c></tag>
           <item>
             <p>This option is not recommended.</p>
diff --git a/lib/compiler/src/compile.erl b/lib/compiler/src/compile.erl
index d894694c79..7a0531cb2b 100644
--- a/lib/compiler/src/compile.erl
+++ b/lib/compiler/src/compile.erl
@@ -210,8 +210,11 @@ do_compile(Input, Opts0) ->
                               {error,Reason}
                       end
              end,
-    %% Dialyzer has already spawned workers.
-    case lists:member(dialyzer, Opts) of
+    %% Some tools, like Dialyzer, has already spawned workers
+    %% and spawning extra workers actually slow the compilation
+    %% down instead of speeding it up, so we provide a mechanism
+    %% to bypass the compiler process.
+    case lists:member(no_spawn_compiler_process, Opts) of
         true ->
             IntFun();
         false ->
diff --git a/lib/dialyzer/src/dialyzer_utils.erl b/lib/dialyzer/src/dialyzer_utils.erl
index abd89034f3..ebe4040c34 100644
--- a/lib/dialyzer/src/dialyzer_utils.erl
+++ b/lib/dialyzer/src/dialyzer_utils.erl
@@ -643,7 +643,7 @@ sets_filter([Mod|Mods], ExpTypes) ->
 src_compiler_opts() ->
   [no_copt, to_core, binary, return_errors,
    no_inline, strict_record_tests, strict_record_updates,
-   dialyzer].
+   dialyzer, no_spawn_compiler_process].
 
 -spec format_errors([{module(), string()}]) -> [string()].
 
-- 
cgit v1.2.3