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, 30 insertions, 1 deletions

diff --git a/src/test/scala/chiselTests/aop/SelectSpec.scala b/src/test/scala/chiselTests/aop/SelectSpec.scala
index 46c62d67..e09e78c8 100644
--- a/src/test/scala/chiselTests/aop/SelectSpec.scala
+++ b/src/test/scala/chiselTests/aop/SelectSpec.scala
@@ -163,7 +163,7 @@ class SelectSpec extends ChiselFlatSpec {
       val out = IO(Output(UInt(8.W)))
       out := in
     }
-    class Top extends MultiIOModule {
+    class Top extends Module {
       val in = IO(Input(UInt(8.W)))
       val out = IO(Output(UInt(8.W)))
       val inst0 = Module(new Child)
@@ -182,5 +182,34 @@ class SelectSpec extends ChiselFlatSpec {
     Select.instances(top) should equal (Seq(top.inst0))
   }
 
+  "Using Definition/Instance with Injecting Aspects" should "throw an error" in {
+    import chisel3.experimental.CloneModuleAsRecord
+    import chisel3.experimental.hierarchy._
+    @instantiable
+    class Child extends RawModule {
+      @public val in = IO(Input(UInt(8.W)))
+      @public val out = IO(Output(UInt(8.W)))
+      out := in
+    }
+    class Top extends Module {
+      val in = IO(Input(UInt(8.W)))
+      val out = IO(Output(UInt(8.W)))
+      val definition = Definition(new Child)
+      val inst0 = Instance(definition)
+      val inst1 = Instance(definition)
+      inst0.in := in
+      inst1.in := inst0.out
+      out := inst1.out
+    }
+    val top = ChiselGeneratorAnnotation(() => {
+      new Top()
+    }).elaborate
+      .collectFirst { case DesignAnnotation(design: Top) => design }
+      .get
+    intercept[Exception] { Select.collectDeep(top) { case x => x } }
+    intercept[Exception] { Select.getDeep(top)(x => Seq(x)) }
+    intercept[Exception] { Select.instances(top) }
+  }
+
 }