Add RawString ExtModule parameter support

While unsafe, this supports Verilog parameter types.
Tests now require Verilator 3.884+ to pass.

4 files changed, 24 insertions, 5 deletions

diff --git a/src/main/antlr4/FIRRTL.g4 b/src/main/antlr4/FIRRTL.g4
index f4d9d3f8..70716c94 100644
--- a/src/main/antlr4/FIRRTL.g4
+++ b/src/main/antlr4/FIRRTL.g4
@@ -97,6 +97,7 @@ parameter
   : 'parameter' id '=' IntLit NEWLINE
   | 'parameter' id '=' StringLit NEWLINE
   | 'parameter' id '=' DoubleLit NEWLINE
+  | 'parameter' id '=' RawString NEWLINE
   ;
 
 moduleBlock
@@ -321,7 +322,16 @@ HexDigit
   ;
 
 StringLit
-  : '"' ('\\"'|.)*? '"'
+  : '"' UnquotedString? '"'
+  ;
+
+RawString
+  : '\'' UnquotedString? '\''
+  ;
+
+fragment
+UnquotedString
+  : ('\\"'|~[\r\n])+?
   ;
 
 FileInfo
diff --git a/src/main/scala/firrtl/Emitter.scala b/src/main/scala/firrtl/Emitter.scala
index e3a146e2..5a4420c6 100644
--- a/src/main/scala/firrtl/Emitter.scala
+++ b/src/main/scala/firrtl/Emitter.scala
@@ -89,6 +89,7 @@ class VerilogEmitter extends Emitter {
     case StringParam(name, value) =>
       val strx = "\"" + VerilogStringLitHandler.escape(value) + "\""
       s".${name}($strx)"
+    case RawStringParam(name, value) => s".$name($value)"
   }
   def emit(x: Any)(implicit w: Writer) { emit(x, 0) }
   def emit(x: Any, top: Int)(implicit w: Writer) {
diff --git a/src/main/scala/firrtl/Visitor.scala b/src/main/scala/firrtl/Visitor.scala
index 03be0c4e..5e07668a 100644
--- a/src/main/scala/firrtl/Visitor.scala
+++ b/src/main/scala/firrtl/Visitor.scala
@@ -119,10 +119,11 @@ class Visitor(infoMode: InfoMode) extends FIRRTLBaseVisitor[FirrtlNode] {
 
   private def visitParameter[FirrtlNode](ctx: FIRRTLParser.ParameterContext): Param = {
     val name = ctx.id.getText
-    (ctx.IntLit, ctx.StringLit, ctx.DoubleLit) match {
-      case (int, null, null) => IntParam(name, string2BigInt(int.getText))
-      case (null, str, null) => StringParam(name, visitStringLit(str))
-      case (null, null, dbl) => DoubleParam(name, dbl.getText.toDouble)
+    (ctx.IntLit, ctx.StringLit, ctx.DoubleLit, ctx.RawString) match {
+      case (int, null, null, null) => IntParam(name, string2BigInt(int.getText))
+      case (null, str, null, null) => StringParam(name, visitStringLit(str))
+      case (null, null, dbl, null) => DoubleParam(name, dbl.getText.toDouble)
+      case (null, null, null, raw) => RawStringParam(name, raw.getText.tail.init) // Remove "\'"s
       case _ => throw new Exception(s"Internal error: Visiting impossible parameter ${ctx.getText}")
     }
   }
diff --git a/src/main/scala/firrtl/ir/IR.scala b/src/main/scala/firrtl/ir/IR.scala
index b9b31427..236a7884 100644
--- a/src/main/scala/firrtl/ir/IR.scala
+++ b/src/main/scala/firrtl/ir/IR.scala
@@ -457,6 +457,13 @@ case class DoubleParam(name: String, value: Double) extends Param {
 case class StringParam(name: String, value: StringLit) extends Param {
   override def serialize: String = super.serialize + value.serialize
 }
+/** Raw String Parameter
+  * Useful for Verilog type parameters
+  * @note Firrtl doesn't guarantee anything about this String being legal in any backend
+  */
+case class RawStringParam(name: String, value: String) extends Param {
+  override def serialize: String = super.serialize + s"'$value'"
+}
 
 /** Base class for modules */
 abstract class DefModule extends FirrtlNode with IsDeclaration {