Don't invalidate ExtModule ports in an explicitInvalidate = true context (backport #2795) (#2799)

* Don't invalidate ExtModule ports in an explicitInvalidate = true context (#2795)

* Don't invalidate ExtModule ports in an explicitInvalidate = true context

ExtModule ports were previously invalidated in the emitted FIRRTL, which is correct in a NonStrict / `Chisel._` compatibility context but not in newer chisel3 code where `explicitInvalidate = true`.

(cherry picked from commit 8e24a281545d25f6501dcc872eabdfb30bacd69d)

# Conflicts:
#	core/src/main/scala/chisel3/BlackBox.scala

* Resolve backport conflicts

Co-authored-by: Jared Barocsi <82000041+jared-barocsi@users.noreply.github.com>
Co-authored-by: Jack Koenig <koenig@sifive.com>

1 files changed, 17 insertions, 0 deletions

diff --git a/src/test/scala/chiselTests/ExtModule.scala b/src/test/scala/chiselTests/ExtModule.scala
index b5a8ff7c..3ab4cc32 100644
--- a/src/test/scala/chiselTests/ExtModule.scala
+++ b/src/test/scala/chiselTests/ExtModule.scala
@@ -88,6 +88,17 @@ class ExtModuleWithFlatIOTester extends Module {
   io <> inst.badIO
 }
 
+class ExtModuleInvalidatedTester extends Module {
+  val in = IO(Input(UInt(8.W)))
+  val out = IO(Output(UInt(8.W)))
+  val inst = Module(new ExtModule {
+    val in = IO(Input(UInt(8.W)))
+    val out = IO(Output(UInt(8.W)))
+  })
+  inst.in := in
+  out := inst.out
+}
+
 class ExtModuleSpec extends ChiselFlatSpec {
   "A ExtModule inverter" should "work" in {
     assertTesterPasses({ new ExtModuleTester }, Seq("/chisel3/BlackBoxTest.v"), TesterDriver.verilatorOnly)
@@ -117,4 +128,10 @@ class ExtModuleSpec extends ChiselFlatSpec {
     chirrtl should include("inst.in <= io.in")
     chirrtl shouldNot include("badIO")
   }
+
+  it should "not have invalidated ports in a chisel3._ context" in {
+    val chirrtl = ChiselStage.emitChirrtl(new ExtModuleInvalidatedTester)
+    chirrtl shouldNot include("inst.in is invalid")
+    chirrtl shouldNot include("inst.out is invalid")
+  }
 }