Runtime API deprecation warnings (#761)

Add runtime warnings for use of deprecated Chisel methods. This is done using a macro that takes the message from a `@deprecated` annotation, and adds a call to `Builder.deprecated`.

Reasoning is that by default, Scala doesn't print all deprecations, and that it's somewhat tricky to notice them - yet some support questions revolve around the use of deprecated and terribad API. This now prints warnings for uses of deprecated functions at runtime, and aggregates them by error and line to avoid spam. Also included is convenient information on enabling scalac deprecations.

This also changes how line numbers for Chisel's error facility is determined, using prefix string comparison of the stack trace element classnames, instead of checking if the class is a subtype of UserModule. The previous one (specifically, calls to Class.forName) seems to interact badly with reflection-based cloneType when called at scale. This should also give more accurate reporting of errors that are in user code but outside of a UserModule.

It turns out that `@deprecated` on macro functions don't do anything, so this changes the tags to the functions that the macros point to, which seems to work properly. It also turns out that there's a bunch of uses of deprecated functions in chiselTests which needs to be fixed.

Not all `@deprecated` functions are also annotated with `@chiselRuntimeDeprecation`, because they're still used in Chisel internals, and we can't track whether they're called by the user or by Chisel and it will give a misleading error. These are a small amount of functions.

1 files changed, 3 insertions, 2 deletions

diff --git a/src/main/scala/chisel3/util/Valid.scala b/src/main/scala/chisel3/util/Valid.scala
index 95f0dcea..67a1a362 100644
--- a/src/main/scala/chisel3/util/Valid.scala
+++ b/src/main/scala/chisel3/util/Valid.scala
@@ -7,13 +7,14 @@ package chisel3.util
 
 import chisel3._
 import chisel3.core.CompileOptions
+import chisel3.experimental.DataMirror
 import chisel3.internal.naming.chiselName  // can't use chisel3_ version because of compile order
 
 /** An Bundle containing data and a signal determining if it is valid */
 class Valid[+T <: Data](gen: T) extends Bundle
 {
   val valid = Output(Bool())
-  val bits  = Output(gen.chiselCloneType)
+  val bits  = Output(gen)
   def fire(dummy: Int = 0): Bool = valid
   override def cloneType: this.type = Valid(gen).asInstanceOf[this.type]
 }
@@ -39,7 +40,7 @@ object Pipe
   @chiselName
   def apply[T <: Data](enqValid: Bool, enqBits: T, latency: Int)(implicit compileOptions: CompileOptions): Valid[T] = {
     if (latency == 0) {
-      val out = Wire(Valid(enqBits))
+      val out = Wire(Valid(chiselTypeOf(enqBits)))
       out.valid := enqValid
       out.bits := enqBits
       out