Add Definition and Instance API (#2045)

This introduces a new experimental API for module instantiation that disentagles
elaborating the definition (or implementation) from instantiation of
a given module. This solves Chisel's longstanding reliance on
"Deduplication" for generating Verilog with multiple instances of the
same module.

The new API resides in package chisel3.experimental.hierarchy. Please
see the hierarchy ScalaDoc, documentation, and tests for examples of
use.

Co-authored-by: Jack Koenig <koenig@sifive.com>
Co-authored-by: Megan Wachs <megan@sifive.com>
Co-authored-by: Schuyler Eldridge <schuyler.eldridge@sifive.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/plugin/src/main/scala/chisel3/internal/plugin/ChiselComponent.scala b/plugin/src/main/scala/chisel3/internal/plugin/ChiselComponent.scala
index b1302ba3..af22e6a7 100644
--- a/plugin/src/main/scala/chisel3/internal/plugin/ChiselComponent.scala
+++ b/plugin/src/main/scala/chisel3/internal/plugin/ChiselComponent.scala
@@ -82,6 +82,7 @@ class ChiselComponent(val global: Global) extends PluginComponent with TypingTra
     private val shouldMatchData      : Type => Boolean = shouldMatchGen(tq"chisel3.Data")
     private val shouldMatchDataOrMem : Type => Boolean = shouldMatchGen(tq"chisel3.Data", tq"chisel3.MemBase[_]")
     private val shouldMatchModule    : Type => Boolean = shouldMatchGen(tq"chisel3.experimental.BaseModule")
+    private val shouldMatchInstance  : Type => Boolean = shouldMatchGen(tq"chisel3.experimental.hierarchy.Instance[_]")
 
     // Given a type tree, infer the type and return it
     private def inferType(t: Tree): Type = localTyper.typed(t, nsc.Mode.TYPEmode).tpe
@@ -188,6 +189,11 @@ class ChiselComponent(val global: Global) extends PluginComponent with TypingTra
           val newRHS = transform(rhs)
           val named = q"chisel3.internal.plugin.autoNameRecursively($str)($newRHS)"
           treeCopy.ValDef(dd, mods, name, tpt, localTyper typed named)
+        } else if (shouldMatchInstance(tpe)) {
+          val str = stringFromTermName(name)
+          val newRHS = transform(rhs)
+          val named = q"chisel3.internal.plugin.autoNameRecursively($str)($newRHS)"
+          treeCopy.ValDef(dd, mods, name, tpt, localTyper typed named)
         } else {
           // Otherwise, continue
           super.transform(tree)