Allow Side Effecting Statement to have Names (#2057)

* firrtl: add optional statement labels for stop, printf, assert, assume and cover

* test: parsing of statement labels

* ir: ensure that name is properly retained

* SymbolTable: add support for labled statements

* test: parsing statement labels

* test: lower types name collisions with named statements

* ignore empty names

* Inline: deal with named and unnamed statements

* RemoveWires: treat stop, printf and verification statements as "others"

* test: fix InlineInstance tests

* DeadCodeEliminations: statements are now als declarations

* CheckHighForm: ensure that statement names are not used as references

* CheckSpec: throw error if statement name collides

* add pass to automatically add missing statement names

* check: make sure that two statements cannot have the same name

* stmtLabel -> stmtName

* scalafmt

* add statement names to spec

* spec: meta data -> metadata

* EnsureStatementNames: explain naming algorithm

* remove returns

* better namespace use

* ir: add CanBeReferenced trait

* ir: add newline as jack requested

1 files changed, 4 insertions, 0 deletions

diff --git a/src/main/scala/firrtl/analyses/SymbolTable.scala b/src/main/scala/firrtl/analyses/SymbolTable.scala
index 3b304bc1..e4a53444 100644
--- a/src/main/scala/firrtl/analyses/SymbolTable.scala
+++ b/src/main/scala/firrtl/analyses/SymbolTable.scala
@@ -87,6 +87,10 @@ object SymbolTable {
     case d: DefNode     => table.declare(d)
     case d: DefWire     => table.declare(d)
     case d: DefRegister => table.declare(d)
+    // Matches named statements like printf, stop, assert, assume, cover if the name is not empty.
+    // Empty names are allowed for backwards compatibility reasons and
+    // indicate that the entity has essentially no name.
+    case s: IsDeclaration if s.name.nonEmpty => table.declare(s.name, UnknownType, firrtl.UnknownKind)
     case other => other.foreachStmt(scanStatement)
   }
 }