Remove unused Builder methods (#4647)

Remove some Builder methods which have no users.  These methods may be
useful, however, they can be added back if necessary.

Signed-off-by: Schuyler Eldridge <[email protected]>

Author: seldridge

core/src/main/scala/chisel3/internal/Builder.scala

@@ -590,8 +590,6 @@ private[chisel3] object Builder extends LazyLogging {
 
   // Returns the current dynamic context
   def captureContext(): DynamicContext = dynamicContext
-  // Sets the current dynamic contents
-  def restoreContext(dc: DynamicContext) = dynamicContextVar.value = Some(dc)
 
   // Ensure we have a thread-specific ChiselContext
   private val chiselContext = new ThreadLocal[ChiselContext] {
@@ -600,18 +598,6 @@ private[chisel3] object Builder extends LazyLogging {
     }
   }
 
-  // Initialize any singleton objects before user code inadvertently inherits them.
-  private def initializeSingletons(): Unit = {
-    // This used to contain:
-    //    val dummy = core.DontCare
-    //  but this would occasionally produce hangs due to static initialization deadlock
-    //  when Builder initialization collided with chisel3.package initialization of the DontCare value.
-    // See:
-    //  http://ternarysearch.blogspot.com/2013/07/static-initialization-deadlock.html
-    //  https://bugs.openjdk.java.net/browse/JDK-8037567
-    //  https://stackoverflow.com/questions/28631656/runnable-thread-state-but-in-object-wait
-  }
-
   def namingStackOption: Option[NamingStack] = dynamicContextVar.value.map(_.namingStack)
 
   def idGen: IdGen = chiselContext.get.idGen
@@ -636,7 +622,6 @@ private[chisel3] object Builder extends LazyLogging {
   def newAnnotations: ArrayBuffer[ChiselMultiAnnotation] = dynamicContext.newAnnotations
 
   def annotationSeq:         AnnotationSeq = dynamicContext.annotationSeq
-  def namingStack:           NamingStack = dynamicContext.namingStack
   def importedDefinitionMap: Map[String, String] = dynamicContext.importedDefinitionMap
 
   def unnamedViews:  ArrayBuffer[Data] = dynamicContext.unnamedViews
@@ -734,14 +719,6 @@ private[chisel3] object Builder extends LazyLogging {
   def retrieveParent(module: BaseModule, context: BaseModule): Option[BaseModule] = {
     module._parent
   }
-  def forcedModule: BaseModule = currentModule match {
-    case Some(module) => module
-    case None =>
-      throwException(
-        "Error: Not in a Module. Likely cause: Missed Module() wrap or bare chisel API call."
-        // A bare api call is, e.g. calling Wire() from the scala console).
-      )
-  }
   def referenceUserModule: RawModule = {
     currentModule match {
       case Some(module: RawModule) => module
@@ -795,8 +772,6 @@ private[chisel3] object Builder extends LazyLogging {
     dynamicContext.whenStack = s
   }
 
-  def currentWhen: Option[WhenContext] = dynamicContext.whenStack.headOption
-
   def blockStack: List[Block] = dynamicContext.blockStack
   def blockStack_=(s: List[Block]): Unit = {
     dynamicContext.blockStack = s
@@ -1198,8 +1173,6 @@ private[chisel3] object Builder extends LazyLogging {
     chiselContext.get().modulePrefixSeperator
   }
 
-  initializeSingletons()
-
   /** The representation of the state of the [[Builder]] at a current point in
     * time.  This is intended to capture _enough_ information to insert hardware
     * at another point in the circuit.