Artefact output (#545)

* build: stop using empty .prm file

* generator: general-purpose mechanism for creating elaboration artefacts

src/main/scala/coreplex/RISCVPlatform.scala

@@ -31,9 +31,7 @@ trait CoreplexRISCVPlatform extends CoreplexNetwork {
 
   lazy val configString = {
     val managers = l1tol2.node.edgesIn(0).manager.managers
-    // Use the existing config string if the user overrode it
-    ConfigStringOutput.contents.getOrElse(
-      rocketchip.GenerateConfigString(p, clint, plic, managers))
+    rocketchip.GenerateConfigString(p, clint, plic, managers)
   }
 }
 
@@ -58,5 +56,5 @@ trait CoreplexRISCVPlatformModule extends CoreplexNetworkModule {
   outer.clint.module.io.rtcTick := Reg(init = Bool(false), next=(rtcSync & (~rtcLast)))
 
   println(s"\nGenerated Configuration String\n${outer.configString}")
-  ConfigStringOutput.contents = Some(outer.configString)
+  ElaborationArtefacts.add("cfg", outer.configString)
 }

src/main/scala/groundtest/Generator.scala

@@ -5,7 +5,6 @@ package groundtest
 object Generator extends util.GeneratorApp {
   val longName = names.topModuleProject + "." + names.configs
   generateFirrtl
-  generateGraphML
   generateTestSuiteMakefrags // TODO: Needed only for legacy make targets
-  generateParameterDump // TODO: Needed only for legacy make targets
+  generateArtefacts
 }

src/main/scala/rocketchip/BaseTop.scala

@@ -13,7 +13,7 @@ import util._
 import rocket._
 
 abstract class BareTop(implicit p: Parameters) extends LazyModule {
-  TopModule.contents = Some(this)
+  ElaborationArtefacts.add("graphml", graphML)
 }
 
 abstract class BareTopBundle[+L <: BareTop](_outer: L) extends GenericParameterizedBundle(_outer) {

src/main/scala/rocketchip/Generator.scala

@@ -77,7 +77,5 @@ object Generator extends util.GeneratorApp {
   val longName = names.topModuleProject + "." + names.configs
   generateFirrtl
   generateTestSuiteMakefrags
-  generateConfigString
-  generateGraphML
-  generateParameterDump
+  generateArtefacts
 }

src/main/scala/unittest/Generator.scala

@@ -5,7 +5,6 @@ package unittest
 object Generator extends util.GeneratorApp {
   val longName = names.topModuleProject + "." + names.configs
   generateFirrtl
-  generateGraphML
   generateTestSuiteMakefrags // TODO: Needed only for legacy make targets
-  generateParameterDump // TODO: Needed only for legacy make targets
+  generateArtefacts
 }

src/main/scala/util/GeneratorUtils.scala

@@ -103,26 +103,17 @@ trait GeneratorApp extends App with HasGeneratorUtilities {
     TestGeneration.addSuite(DefaultTestSuites.singleRegression)
   } 
 
-  /** Output a global Parameter dump, which an external script can turn into Verilog headers. */
-  def generateParameterDump {
-    writeOutputFile(td, s"$longName.prm", "")
-  }
-
-  /** Output a global ConfigString, for use by the RISC-V software ecosystem. */
-  def generateConfigString {
-    ConfigStringOutput.contents.foreach(c => writeOutputFile(td, s"${names.configs}.cfg", c))
-  }
-
-  /** Output a global LazyModule topology for documentation purposes. */
-  def generateGraphML {
-    TopModule.contents.foreach(lm => writeOutputFile(td, s"${names.configs}.graphml", lm.graphML))
+  /** Output files created as a side-effect of elaboration */
+  def generateArtefacts {
+    ElaborationArtefacts.files.foreach { case (extension, contents) =>
+      writeOutputFile(td, s"${names.configs}.${extension}", contents ())
+    }
   }
 }
 
-object ConfigStringOutput {
-  var contents: Option[String] = None
-}
-
-object TopModule {
-  var contents: Option[LazyModule] = None
+object ElaborationArtefacts {
+  var files: Seq[(String, () => String)] = Nil
+  def add(extension: String, contents: => String) {
+    files = (extension, () => contents) +: files
+  }
 }