From b72cc42f4f23906db0f201b1d9543a64accbc2ec Mon Sep 17 00:00:00 2001
From: mergify[bot]
Date: Thu, 6 Oct 2022 21:26:30 +0000
Subject: Update toPrintable for Enums (#2707) (#2763)

(cherry picked from commit 0ff99ca8d573e3487ef496a21c95d962689c3cba)

Co-authored-by: Aditya Naik <91489422+adkian-sifive@users.noreply.github.com>---
 core/src/main/scala/chisel3/StrongEnum.scala | 25 ++++++++++++++++-
 src/test/scala/chiselTests/StrongEnum.scala  | 42 ++++++++++++++++++++++++++++
 2 files changed, 66 insertions(+), 1 deletion(-)

diff --git a/core/src/main/scala/chisel3/StrongEnum.scala b/core/src/main/scala/chisel3/StrongEnum.scala
index 6d8ceb2f..3c9f4105 100644
--- a/core/src/main/scala/chisel3/StrongEnum.scala
+++ b/core/src/main/scala/chisel3/StrongEnum.scala
@@ -251,7 +251,28 @@ abstract class EnumType(private[chisel3] val factory: EnumFactory, selfAnnotatin
 
   protected def enumTypeName: String = factory.enumTypeName
 
-  def toPrintable: Printable = FullName(this) // TODO: Find a better pretty printer
+  def toPrintable: Printable = {
+    implicit val sourceInfo = UnlocatableSourceInfo
+    implicit val compileOptions = ExplicitCompileOptions.Strict
+    val allNames = factory.allNames.zip(factory.all)
+    val nameSize = allNames.map(_._1.length).max
+    def leftPad(str: String): String = {
+      str.reverse.padTo(nameSize, ' ').reverse
+    }
+    val allNamesPadded = allNames.map { case (name, value) => leftPad(name) -> value }
+
+    val result = Wire(Vec(nameSize, UInt(8.W))).suggestName(s"_${enumTypeName}Printable")
+    result.foreach(_ := '?'.U)
+
+    for ((name, value) <- allNamesPadded) {
+      when(this === value) {
+        for ((r, c) <- result.zip(name)) {
+          r := c.toChar.U
+        }
+      }
+    }
+    result.map(Character(_)).foldLeft(p"")(_ + _)
+  }
 }
 
 abstract class EnumFactory {
@@ -284,6 +305,8 @@ abstract class EnumFactory {
   def getWidth: Int = width.get
 
   def all: Seq[Type] = enumInstances
+  /* Accessor for Seq of names in enumRecords */
+  def allNames: Seq[String] = enumNames
 
   private[chisel3] def nameOfValue(id: BigInt): Option[String] = {
     enumRecords.find(_.inst.litValue == id).map(_.name)
diff --git a/src/test/scala/chiselTests/StrongEnum.scala b/src/test/scala/chiselTests/StrongEnum.scala
index 5b1b13fd..cee1777e 100644
--- a/src/test/scala/chiselTests/StrongEnum.scala
+++ b/src/test/scala/chiselTests/StrongEnum.scala
@@ -164,6 +164,39 @@ class StrongEnumFSM extends Module {
   }
 }
 
+object Opcode extends ChiselEnum {
+  val load = Value(0x03.U)
+  val imm = Value(0x13.U)
+  val auipc = Value(0x17.U)
+  val store = Value(0x23.U)
+  val litValues = List(0x03.U, 0x13.U, 0x17.U, 0x23.U)
+}
+
+class PrintableExecutionTest extends BasicTester {
+  val (count, done) = Counter(true.B, 6)
+  val w = WireDefault(Opcode.load)
+  when(count === 0.U) {
+    w := Opcode.load
+  }
+  when(count === 1.U) {
+    w := Opcode.imm
+  }
+  when(count === 2.U) {
+    w := Opcode.auipc
+  }
+  when(count === 3.U) {
+    w := Opcode.store
+  }
+  when(count === 4.U) { // invalid state
+    val invalidWire = WireInit(UInt(6.W), 0.U)
+    w := Opcode.safe(invalidWire)._1
+  }
+  when(done) {
+    stop()
+  }
+  printf(cf"'$w'\n")
+}
+
 class CastToUIntTester extends BasicTester {
   for ((enum, lit) <- EnumExample.all.zip(EnumExample.litValues)) {
     val mod = Module(new CastToUInt)
@@ -555,6 +588,15 @@ class StrongEnumSpec extends ChiselFlatSpec with Utils {
   it should "correctly check if the enumeration is one of the values in a given sequence" in {
     assertTesterPasses(new IsOneOfTester)
   }
+
+  it should "work with Printables" in {
+    val (log, _, _) = grabStdOutErr(assertTesterPasses { new PrintableExecutionTest })
+    log should include("load")
+    log should include("imm")
+    log should include("auipc")
+    log should include("store")
+    log should include("?????")
+  }
 }
 
 class StrongEnumAnnotator extends Module {
-- 
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