Don't modify the Builder prefix if reinvoking suggestName on a Data (backport #2789) (#2790)

* Only set the chisel3 Builder prefix during the first invocation of suggestName

(cherry picked from commit b684506abab2f7b99d56181d548cb8119d317323)

# Conflicts:
#	core/src/main/scala/chisel3/internal/Builder.scala

* Add simple test to show bug fix

(cherry picked from commit 255068b105de77a045a0016e3a157b52a81c86d6)

* Fix merge conflict

* Fix test to not use Hardware inside a bundle for prefixing

Co-authored-by: Jared Barocsi <jared.barocsi@sifive.com>

2 files changed, 32 insertions, 3 deletions

diff --git a/core/src/main/scala/chisel3/internal/Builder.scala b/core/src/main/scala/chisel3/internal/Builder.scala
index 9f79fe1e..e3dfff09 100644
--- a/core/src/main/scala/chisel3/internal/Builder.scala
+++ b/core/src/main/scala/chisel3/internal/Builder.scala
@@ -170,9 +170,12 @@ private[chisel3] trait HasId extends InstanceId {
     * @return this object
     */
   def suggestName(seed: => String): this.type = {
-    if (suggested_seed.isEmpty) suggested_seedVar = seed
-    naming_prefix = Builder.getPrefix
-    for (hook <- suggest_postseed_hooks.reverse) { hook(seed) }
+    if (suggested_seed.isEmpty) {
+      suggested_seedVar = seed
+      // Only set the prefix if a seed hasn't been suggested
+      naming_prefix = Builder.getPrefix
+      for (hook <- suggest_postseed_hooks.reverse) { hook(seed) }
+    }
     this
   }
 
diff --git a/src/test/scala/chiselTests/naming/PrefixSpec.scala b/src/test/scala/chiselTests/naming/PrefixSpec.scala
index b5eac1d4..d8cb3348 100644
--- a/src/test/scala/chiselTests/naming/PrefixSpec.scala
+++ b/src/test/scala/chiselTests/naming/PrefixSpec.scala
@@ -521,4 +521,30 @@ class PrefixSpec extends ChiselPropSpec with Utils {
       Select.wires(top).map(_.instanceName) should be(List("nonData_value", "value"))
     }
   }
+  property("Prefixing should not be affected by repeated calls of suggestName") {
+    class Test extends Module {
+      val in = IO(Input(UInt(3.W)))
+      val prefixed = {
+        val wire = Wire(UInt(3.W)).suggestName("wire") // "prefixed_wire"
+        wire := in
+
+        val thisShouldNotBeHere = {
+          // Second suggestName doesn't modify the instanceName since it was
+          // already suggested, but also should not modify the prefix either
+
+          // Incorrect behavior would rename the wire to
+          // "prefixed_thisShouldNotBeHere_wire"
+          wire.suggestName("wire")
+
+          val out = IO(Output(UInt(3.W)))
+          out := wire
+          out
+        }
+        thisShouldNotBeHere
+      }
+    }
+    aspectTest(() => new Test) { top: Test =>
+      Select.wires(top).map(_.instanceName) should be(List("prefixed_wire"))
+    }
+  }
 }