[ETCM-736] Enable compiler optimizations in Prod (#963)

* [ETCM-736] Enable compiler optimizations in Prod

See https://www.lightbend.com/blog/scala-inliner-optimizer

To display optimizations logs : add `"-Yopt-log-inline", "_"`

* [ETCM-736] Restrict inlining to the project

* Update nix patch

Co-authored-by: Jonathan Ringer <[email protected]>

Author: jb-lunatech

build.sbt

@@ -12,6 +12,12 @@ val nixBuild = sys.props.isDefinedAt("nix")
 // Enable dev mode: disable certain flags, etc.
 val mantisDev = sys.props.get("mantisDev").contains("true") || sys.env.get("MANTIS_DEV").contains("true")
 
+lazy val compilerOptimizationsForProd = Seq(
+  "-opt:l:method",  // method-local optimizations
+  "-opt:l:inline",  // inlining optimizations
+  "-opt-inline-from:io.iohk.**" // inlining the project only
+)
+
 // Releasing. https://github.com/olafurpg/sbt-ci-release
 inThisBuild(List(
   organization := "io.iohk",
@@ -47,6 +53,7 @@ def commonSettings(projectName: String): Seq[sbt.Def.Setting[_]] = Seq(
     "-encoding",
     "utf-8"
   ),
+  scalacOptions ++= (if (mantisDev) Seq.empty else compilerOptimizationsForProd),
   scalacOptions in (Compile, console) ~= (_.filterNot(
     Set(
       "-Ywarn-unused-import",

nix/protoc.patch

@@ -1,12 +1,12 @@
 diff --git a/build.sbt b/build.sbt
-index 6bf2b25cb..155de447d 100644
+index 4ac21ff40..ccd34412e 100644
 --- a/build.sbt
 +++ b/build.sbt
-@@ -25,6 +25,7 @@ def commonSettings(projectName: String) = Seq(
-     "-encoding",
-     "UTF-8"
-   ),
+@@ -43,6 +43,7 @@ def commonSettings(projectName: String): Seq[sbt.Def.Setting[_]] = Seq(
+   scalaVersion := `scala-2.13`,
+   // Scalanet snapshots are published to Sonatype after each build.
+   resolvers += "Sonatype OSS Snapshots" at "https://oss.sonatype.org/content/repositories/snapshots",
 +  PB.runProtoc in Compile := (args => Process("@protobuf@/bin/protoc", args)!),
-   scalacOptions in (Compile, console) ~= (_.filterNot(
-     Set(
-       "-Ywarn-unused-import",
+   testOptions in Test += Tests
+     .Argument(TestFrameworks.ScalaTest, "-l", "EthashMinerSpec"), // miner tests disabled by default,
+   scalacOptions := Seq(