diff --git a/bir/src/main/kotlin/gay/pizza/pork/bir/IrBreak.kt b/bir/src/main/kotlin/gay/pizza/pork/bir/IrBreak.kt
index d648c0f..f64ac28 100644
--- a/bir/src/main/kotlin/gay/pizza/pork/bir/IrBreak.kt
+++ b/bir/src/main/kotlin/gay/pizza/pork/bir/IrBreak.kt
@@ -3,7 +3,7 @@ package gay.pizza.pork.bir
 import kotlinx.serialization.Serializable
 
 @Serializable
-data class IrBreak(val target: IrSymbol) : IrCodeElement {
+data class IrBreak(var target: IrSymbol) : IrCodeElement() {
   override fun crawl(block: (IrElement) -> Unit) {
     block(target)
   }
diff --git a/bir/src/main/kotlin/gay/pizza/pork/bir/IrCall.kt b/bir/src/main/kotlin/gay/pizza/pork/bir/IrCall.kt
index b1e169d..c97bba4 100644
--- a/bir/src/main/kotlin/gay/pizza/pork/bir/IrCall.kt
+++ b/bir/src/main/kotlin/gay/pizza/pork/bir/IrCall.kt
@@ -4,10 +4,10 @@ import kotlinx.serialization.Serializable
 
 @Serializable
 data class IrCall(
-  override val target: IrSymbol,
-  val arguments: List<IrCodeElement>,
-  val variableArguments: List<IrCodeElement>?
-) : IrCodeElement, IrSymbolUser {
+  override var target: IrSymbol,
+  var arguments: List<IrCodeElement>,
+  var variableArguments: List<IrCodeElement>?
+) : IrCodeElement(), IrSymbolUser {
   override fun crawl(block: (IrElement) -> Unit) {
     block(target)
     arguments.forEach(block)
diff --git a/bir/src/main/kotlin/gay/pizza/pork/bir/IrCodeBlock.kt b/bir/src/main/kotlin/gay/pizza/pork/bir/IrCodeBlock.kt
index 01bf0fe..d3d6a2a 100644
--- a/bir/src/main/kotlin/gay/pizza/pork/bir/IrCodeBlock.kt
+++ b/bir/src/main/kotlin/gay/pizza/pork/bir/IrCodeBlock.kt
@@ -3,7 +3,7 @@ package gay.pizza.pork.bir
 import kotlinx.serialization.Serializable
 
 @Serializable
-data class IrCodeBlock(val items: List<IrCodeElement>) : IrCodeElement {
+data class IrCodeBlock(var items: List<IrCodeElement>) : IrCodeElement() {
   override fun crawl(block: (IrElement) -> Unit) {
     items.forEach(block)
   }
diff --git a/bir/src/main/kotlin/gay/pizza/pork/bir/IrCodeElement.kt b/bir/src/main/kotlin/gay/pizza/pork/bir/IrCodeElement.kt
index 2885fcb..c068291 100644
--- a/bir/src/main/kotlin/gay/pizza/pork/bir/IrCodeElement.kt
+++ b/bir/src/main/kotlin/gay/pizza/pork/bir/IrCodeElement.kt
@@ -3,4 +3,4 @@ package gay.pizza.pork.bir
 import kotlinx.serialization.Serializable
 
 @Serializable
-sealed interface IrCodeElement : IrElement
+sealed class IrCodeElement : IrElement()
diff --git a/bir/src/main/kotlin/gay/pizza/pork/bir/IrConditional.kt b/bir/src/main/kotlin/gay/pizza/pork/bir/IrConditional.kt
index ccca1a8..165cf83 100644
--- a/bir/src/main/kotlin/gay/pizza/pork/bir/IrConditional.kt
+++ b/bir/src/main/kotlin/gay/pizza/pork/bir/IrConditional.kt
@@ -4,10 +4,10 @@ import kotlinx.serialization.Serializable
 
 @Serializable
 data class IrConditional(
-  val conditional: IrCodeElement,
-  val ifTrue: IrCodeElement,
-  val ifFalse: IrCodeElement
-) : IrCodeElement {
+  var conditional: IrCodeElement,
+  var ifTrue: IrCodeElement,
+  var ifFalse: IrCodeElement
+) : IrCodeElement() {
   override fun crawl(block: (IrElement) -> Unit) {
     block(conditional)
     block(ifTrue)
diff --git a/bir/src/main/kotlin/gay/pizza/pork/bir/IrConstant.kt b/bir/src/main/kotlin/gay/pizza/pork/bir/IrConstant.kt
index fc29f64..5097cfc 100644
--- a/bir/src/main/kotlin/gay/pizza/pork/bir/IrConstant.kt
+++ b/bir/src/main/kotlin/gay/pizza/pork/bir/IrConstant.kt
@@ -3,24 +3,24 @@ package gay.pizza.pork.bir
 import kotlinx.serialization.Serializable
 
 @Serializable
-sealed interface IrConstant : IrCodeElement {
+sealed class IrConstant : IrCodeElement() {
   override fun crawl(block: (IrElement) -> Unit) {}
 }
 
 @Serializable
-data class IrIntegerConstant(val value: Int) : IrConstant
+data class IrIntegerConstant(var value: Int) : IrConstant()
 
 @Serializable
-data class IrLongConstant(val value: Long) : IrConstant
+data class IrLongConstant(var value: Long) : IrConstant()
 
 @Serializable
-data class IrDoubleConstant(val value: Double) : IrConstant
+data class IrDoubleConstant(var value: Double) : IrConstant()
 
 @Serializable
-data class IrStringConstant(val value: String) : IrConstant
+data class IrStringConstant(var value: String) : IrConstant()
 
 @Serializable
-data class IrBooleanConstant(val value: Boolean) : IrConstant
+data class IrBooleanConstant(var value: Boolean) : IrConstant()
 
 @Serializable
-data object IrNoneConstant : IrConstant
+data object IrNoneConstant : IrConstant()
diff --git a/bir/src/main/kotlin/gay/pizza/pork/bir/IrContinue.kt b/bir/src/main/kotlin/gay/pizza/pork/bir/IrContinue.kt
index 444f304..313ef5b 100644
--- a/bir/src/main/kotlin/gay/pizza/pork/bir/IrContinue.kt
+++ b/bir/src/main/kotlin/gay/pizza/pork/bir/IrContinue.kt
@@ -3,7 +3,7 @@ package gay.pizza.pork.bir
 import kotlinx.serialization.Serializable
 
 @Serializable
-data class IrContinue(override val target: IrSymbol) : IrCodeElement, IrSymbolUser {
+data class IrContinue(override var target: IrSymbol) : IrCodeElement(), IrSymbolUser {
   override fun crawl(block: (IrElement) -> Unit) {
     block(target)
   }
diff --git a/bir/src/main/kotlin/gay/pizza/pork/bir/IrDeclare.kt b/bir/src/main/kotlin/gay/pizza/pork/bir/IrDeclare.kt
index 7331de2..eeae8e4 100644
--- a/bir/src/main/kotlin/gay/pizza/pork/bir/IrDeclare.kt
+++ b/bir/src/main/kotlin/gay/pizza/pork/bir/IrDeclare.kt
@@ -3,7 +3,7 @@ package gay.pizza.pork.bir
 import kotlinx.serialization.Serializable
 
 @Serializable
-data class IrDeclare(override val symbol: IrSymbol, val value: IrCodeElement) : IrCodeElement, IrSymbolOwner {
+data class IrDeclare(override var symbol: IrSymbol, var value: IrCodeElement) : IrCodeElement(), IrSymbolOwner {
   override fun crawl(block: (IrElement) -> Unit) {
     value.crawl(block)
   }
diff --git a/bir/src/main/kotlin/gay/pizza/pork/bir/IrDefinition.kt b/bir/src/main/kotlin/gay/pizza/pork/bir/IrDefinition.kt
index eefc1ab..030b7ef 100644
--- a/bir/src/main/kotlin/gay/pizza/pork/bir/IrDefinition.kt
+++ b/bir/src/main/kotlin/gay/pizza/pork/bir/IrDefinition.kt
@@ -4,11 +4,11 @@ import kotlinx.serialization.Serializable
 
 @Serializable
 data class IrDefinition(
-  override val symbol: IrSymbol,
-  val type: IrDefinitionType,
-  val arguments: List<IrFunctionArgument>,
-  val code: IrCodeBlock
-) : IrElement, IrSymbolOwner {
+  override var symbol: IrSymbol,
+  var type: IrDefinitionType,
+  var arguments: List<IrFunctionArgument>,
+  var code: IrCodeBlock
+) : IrElement(), IrSymbolOwner {
   override fun crawl(block: (IrElement) -> Unit) {
     block(symbol)
     arguments.forEach(block)
diff --git a/bir/src/main/kotlin/gay/pizza/pork/bir/IrElement.kt b/bir/src/main/kotlin/gay/pizza/pork/bir/IrElement.kt
index 86aea1d..8457f5c 100644
--- a/bir/src/main/kotlin/gay/pizza/pork/bir/IrElement.kt
+++ b/bir/src/main/kotlin/gay/pizza/pork/bir/IrElement.kt
@@ -3,6 +3,6 @@ package gay.pizza.pork.bir
 import kotlinx.serialization.Serializable
 
 @Serializable
-sealed interface IrElement {
-  fun crawl(block: (IrElement) -> Unit)
+sealed class IrElement {
+  abstract fun crawl(block: (IrElement) -> Unit)
 }
diff --git a/bir/src/main/kotlin/gay/pizza/pork/bir/IrFunctionArgument.kt b/bir/src/main/kotlin/gay/pizza/pork/bir/IrFunctionArgument.kt
index 7998456..c31d5cc 100644
--- a/bir/src/main/kotlin/gay/pizza/pork/bir/IrFunctionArgument.kt
+++ b/bir/src/main/kotlin/gay/pizza/pork/bir/IrFunctionArgument.kt
@@ -3,6 +3,6 @@ package gay.pizza.pork.bir
 import kotlinx.serialization.Serializable
 
 @Serializable
-data class IrFunctionArgument(override val symbol: IrSymbol) : IrSymbolOwner {
+data class IrFunctionArgument(override var symbol: IrSymbol) : IrElement(), IrSymbolOwner {
   override fun crawl(block: (IrElement) -> Unit) {}
 }
diff --git a/bir/src/main/kotlin/gay/pizza/pork/bir/IrIndex.kt b/bir/src/main/kotlin/gay/pizza/pork/bir/IrIndex.kt
index b590283..f25d47c 100644
--- a/bir/src/main/kotlin/gay/pizza/pork/bir/IrIndex.kt
+++ b/bir/src/main/kotlin/gay/pizza/pork/bir/IrIndex.kt
@@ -3,7 +3,7 @@ package gay.pizza.pork.bir
 import kotlinx.serialization.Serializable
 
 @Serializable
-data class IrIndex(val data: IrCodeElement, val index: IrCodeElement) : IrCodeElement {
+data class IrIndex(var data: IrCodeElement, var index: IrCodeElement) : IrCodeElement() {
   override fun crawl(block: (IrElement) -> Unit) {
     block(data)
     block(index)
diff --git a/bir/src/main/kotlin/gay/pizza/pork/bir/IrInfix.kt b/bir/src/main/kotlin/gay/pizza/pork/bir/IrInfix.kt
index 943ebb8..624968c 100644
--- a/bir/src/main/kotlin/gay/pizza/pork/bir/IrInfix.kt
+++ b/bir/src/main/kotlin/gay/pizza/pork/bir/IrInfix.kt
@@ -3,7 +3,7 @@ package gay.pizza.pork.bir
 import kotlinx.serialization.Serializable
 
 @Serializable
-data class IrInfix(val op: IrInfixOp, val left: IrCodeElement, val right: IrCodeElement) : IrCodeElement {
+data class IrInfix(var op: IrInfixOp, var left: IrCodeElement, var right: IrCodeElement) : IrCodeElement() {
   override fun crawl(block: (IrElement) -> Unit) {
     block(left)
     block(right)
diff --git a/bir/src/main/kotlin/gay/pizza/pork/bir/IrList.kt b/bir/src/main/kotlin/gay/pizza/pork/bir/IrList.kt
index 338d78f..4d62bc7 100644
--- a/bir/src/main/kotlin/gay/pizza/pork/bir/IrList.kt
+++ b/bir/src/main/kotlin/gay/pizza/pork/bir/IrList.kt
@@ -3,7 +3,7 @@ package gay.pizza.pork.bir
 import kotlinx.serialization.Serializable
 
 @Serializable
-data class IrList(val items: List<IrCodeElement>) : IrCodeElement {
+data class IrList(var items: List<IrCodeElement>) : IrCodeElement() {
   override fun crawl(block: (IrElement) -> Unit) {
     items.forEach(block)
   }
diff --git a/bir/src/main/kotlin/gay/pizza/pork/bir/IrListSize.kt b/bir/src/main/kotlin/gay/pizza/pork/bir/IrListSize.kt
index 585663c..1d6578e 100644
--- a/bir/src/main/kotlin/gay/pizza/pork/bir/IrListSize.kt
+++ b/bir/src/main/kotlin/gay/pizza/pork/bir/IrListSize.kt
@@ -3,7 +3,7 @@ package gay.pizza.pork.bir
 import kotlinx.serialization.Serializable
 
 @Serializable
-data class IrListSize(val list: IrCodeElement) : IrCodeElement {
+data class IrListSize(var list: IrCodeElement) : IrCodeElement() {
   override fun crawl(block: (IrElement) -> Unit) {
     block(list)
   }
diff --git a/bir/src/main/kotlin/gay/pizza/pork/bir/IrLoad.kt b/bir/src/main/kotlin/gay/pizza/pork/bir/IrLoad.kt
index f2870ba..fa0d7bc 100644
--- a/bir/src/main/kotlin/gay/pizza/pork/bir/IrLoad.kt
+++ b/bir/src/main/kotlin/gay/pizza/pork/bir/IrLoad.kt
@@ -3,7 +3,7 @@ package gay.pizza.pork.bir
 import kotlinx.serialization.Serializable
 
 @Serializable
-data class IrLoad(override val target: IrSymbol) : IrCodeElement, IrSymbolUser {
+data class IrLoad(override var target: IrSymbol) : IrCodeElement(), IrSymbolUser {
   override fun crawl(block: (IrElement) -> Unit) {
     block(target)
   }
diff --git a/bir/src/main/kotlin/gay/pizza/pork/bir/IrLoop.kt b/bir/src/main/kotlin/gay/pizza/pork/bir/IrLoop.kt
index 61bbf6f..61fb4ae 100644
--- a/bir/src/main/kotlin/gay/pizza/pork/bir/IrLoop.kt
+++ b/bir/src/main/kotlin/gay/pizza/pork/bir/IrLoop.kt
@@ -4,10 +4,10 @@ import kotlinx.serialization.Serializable
 
 @Serializable
 data class IrLoop(
-  override val symbol: IrSymbol,
-  val condition: IrCodeElement,
-  val inner: IrCodeElement
-) : IrCodeElement, IrSymbolOwner {
+  override var symbol: IrSymbol,
+  var condition: IrCodeElement,
+  var inner: IrCodeElement
+) : IrCodeElement(), IrSymbolOwner {
   override fun crawl(block: (IrElement) -> Unit) {
     block(symbol)
     block(condition)
diff --git a/bir/src/main/kotlin/gay/pizza/pork/bir/IrNativeDefinition.kt b/bir/src/main/kotlin/gay/pizza/pork/bir/IrNativeDefinition.kt
index 676f32c..fff2801 100644
--- a/bir/src/main/kotlin/gay/pizza/pork/bir/IrNativeDefinition.kt
+++ b/bir/src/main/kotlin/gay/pizza/pork/bir/IrNativeDefinition.kt
@@ -3,6 +3,6 @@ package gay.pizza.pork.bir
 import kotlinx.serialization.Serializable
 
 @Serializable
-data class IrNativeDefinition(val form: String, val definitions: List<String>) : IrCodeElement {
+data class IrNativeDefinition(var form: String, var definitions: List<String>) : IrCodeElement() {
   override fun crawl(block: (IrElement) -> Unit) {}
 }
diff --git a/bir/src/main/kotlin/gay/pizza/pork/bir/IrPrefix.kt b/bir/src/main/kotlin/gay/pizza/pork/bir/IrPrefix.kt
index 8f43627..b7560cf 100644
--- a/bir/src/main/kotlin/gay/pizza/pork/bir/IrPrefix.kt
+++ b/bir/src/main/kotlin/gay/pizza/pork/bir/IrPrefix.kt
@@ -3,7 +3,7 @@ package gay.pizza.pork.bir
 import kotlinx.serialization.Serializable
 
 @Serializable
-data class IrPrefix(val op: IrPrefixOp, val value: IrCodeElement) : IrCodeElement {
+data class IrPrefix(var op: IrPrefixOp, var value: IrCodeElement) : IrCodeElement() {
   override fun crawl(block: (IrElement) -> Unit) {
     block(value)
   }
diff --git a/bir/src/main/kotlin/gay/pizza/pork/bir/IrReturn.kt b/bir/src/main/kotlin/gay/pizza/pork/bir/IrReturn.kt
index 05dfacb..36b0c3c 100644
--- a/bir/src/main/kotlin/gay/pizza/pork/bir/IrReturn.kt
+++ b/bir/src/main/kotlin/gay/pizza/pork/bir/IrReturn.kt
@@ -3,7 +3,7 @@ package gay.pizza.pork.bir
 import kotlinx.serialization.Serializable
 
 @Serializable
-data class IrReturn(val from: IrSymbol, val value: IrCodeElement) : IrCodeElement {
+data class IrReturn(var from: IrSymbol, var value: IrCodeElement) : IrCodeElement() {
   override fun crawl(block: (IrElement) -> Unit) {
     block(from)
     block(value)
diff --git a/bir/src/main/kotlin/gay/pizza/pork/bir/IrSlab.kt b/bir/src/main/kotlin/gay/pizza/pork/bir/IrSlab.kt
index 3b72be2..6e1a8e4 100644
--- a/bir/src/main/kotlin/gay/pizza/pork/bir/IrSlab.kt
+++ b/bir/src/main/kotlin/gay/pizza/pork/bir/IrSlab.kt
@@ -4,9 +4,10 @@ import kotlinx.serialization.Serializable
 
 @Serializable
 data class IrSlab(
-  val location: IrSlabLocation,
-  val definitions: List<IrDefinition>
-) : IrElement {
+  override var symbol: IrSymbol,
+  var location: IrSlabLocation,
+  var definitions: List<IrDefinition>
+) : IrElement(), IrSymbolOwner {
   override fun crawl(block: (IrElement) -> Unit) {
     block(location)
     definitions.forEach(block)
diff --git a/bir/src/main/kotlin/gay/pizza/pork/bir/IrSlabLocation.kt b/bir/src/main/kotlin/gay/pizza/pork/bir/IrSlabLocation.kt
index e99898b..a750a35 100644
--- a/bir/src/main/kotlin/gay/pizza/pork/bir/IrSlabLocation.kt
+++ b/bir/src/main/kotlin/gay/pizza/pork/bir/IrSlabLocation.kt
@@ -4,8 +4,8 @@ import kotlinx.serialization.Serializable
 
 @Serializable
 data class IrSlabLocation(
-  val form: String,
-  val path: String
-) : IrElement {
+  var form: String,
+  var path: String
+) : IrElement() {
   override fun crawl(block: (IrElement) -> Unit) {}
 }
diff --git a/bir/src/main/kotlin/gay/pizza/pork/bir/IrStore.kt b/bir/src/main/kotlin/gay/pizza/pork/bir/IrStore.kt
index d802e23..bf0ea3d 100644
--- a/bir/src/main/kotlin/gay/pizza/pork/bir/IrStore.kt
+++ b/bir/src/main/kotlin/gay/pizza/pork/bir/IrStore.kt
@@ -3,7 +3,7 @@ package gay.pizza.pork.bir
 import kotlinx.serialization.Serializable
 
 @Serializable
-data class IrStore(override val target: IrSymbol, val value: IrCodeElement) : IrCodeElement, IrSymbolUser {
+data class IrStore(override var target: IrSymbol, var value: IrCodeElement) : IrCodeElement(), IrSymbolUser {
   override fun crawl(block: (IrElement) -> Unit) {
     value.crawl(block)
   }
diff --git a/bir/src/main/kotlin/gay/pizza/pork/bir/IrSuffix.kt b/bir/src/main/kotlin/gay/pizza/pork/bir/IrSuffix.kt
index 9433be9..9204d7e 100644
--- a/bir/src/main/kotlin/gay/pizza/pork/bir/IrSuffix.kt
+++ b/bir/src/main/kotlin/gay/pizza/pork/bir/IrSuffix.kt
@@ -3,7 +3,7 @@ package gay.pizza.pork.bir
 import kotlinx.serialization.Serializable
 
 @Serializable
-data class IrSuffix(val op: IrSuffixOp, override val target: IrSymbol) : IrCodeElement, IrSymbolUser {
+data class IrSuffix(var op: IrSuffixOp, override var target: IrSymbol) : IrCodeElement(), IrSymbolUser {
   override fun crawl(block: (IrElement) -> Unit) {
     block(target)
   }
diff --git a/bir/src/main/kotlin/gay/pizza/pork/bir/IrSymbol.kt b/bir/src/main/kotlin/gay/pizza/pork/bir/IrSymbol.kt
index c3cfeaf..1e0b057 100644
--- a/bir/src/main/kotlin/gay/pizza/pork/bir/IrSymbol.kt
+++ b/bir/src/main/kotlin/gay/pizza/pork/bir/IrSymbol.kt
@@ -3,7 +3,7 @@ package gay.pizza.pork.bir
 import kotlinx.serialization.Serializable
 
 @Serializable
-data class IrSymbol(val id: UInt, val tag: IrSymbolTag, val name: String? = null) : IrElement {
+data class IrSymbol(val id: UInt, val tag: IrSymbolTag, val name: String? = null) : IrElement() {
   override fun crawl(block: (IrElement) -> Unit) {}
 
   override fun equals(other: Any?): Boolean {
diff --git a/bir/src/main/kotlin/gay/pizza/pork/bir/IrSymbolGraph.kt b/bir/src/main/kotlin/gay/pizza/pork/bir/IrSymbolGraph.kt
index 0d89130..1323bbf 100644
--- a/bir/src/main/kotlin/gay/pizza/pork/bir/IrSymbolGraph.kt
+++ b/bir/src/main/kotlin/gay/pizza/pork/bir/IrSymbolGraph.kt
@@ -1,7 +1,10 @@
 package gay.pizza.pork.bir
 
+import kotlinx.serialization.Serializable
+
+@Serializable(with = IrSymbolGraphSerializer::class)
 class IrSymbolGraph {
-  private val edges = mutableSetOf<Pair<IrSymbolUser, IrSymbolOwner>>()
+  private val edges = mutableSetOf<IrSymbolGraphEdge>()
 
   private fun crawlForKnown(known: MutableMap<IrSymbol, IrSymbolOwner>, root: IrElement) {
     if (root is IrSymbolOwner) {
@@ -17,7 +20,7 @@ class IrSymbolGraph {
     if (root is IrSymbolUser) {
       val what = known[root.target]
       if (what != null) {
-        edges.add(root to what)
+        edges.add(IrSymbolGraphEdge(root, what))
       }
     }
 
@@ -26,12 +29,16 @@ class IrSymbolGraph {
     }
   }
 
-  fun crawl(root: IrElement) {
+  fun buildFromRoot(root: IrElement) {
     val known = mutableMapOf<IrSymbol, IrSymbolOwner>()
     crawlForKnown(known, root)
     crawlForAssociations(known, root)
   }
 
+  fun buildFromEdges(edges: Collection<IrSymbolGraphEdge>) {
+    this.edges.addAll(edges)
+  }
+
   fun forEachEdge(block: (IrSymbolUser, IrSymbolOwner) -> Unit) {
     for ((from, to) in edges) {
       block(from, to)
diff --git a/bir/src/main/kotlin/gay/pizza/pork/bir/IrSymbolGraphEdge.kt b/bir/src/main/kotlin/gay/pizza/pork/bir/IrSymbolGraphEdge.kt
new file mode 100644
index 0000000..0d478af
--- /dev/null
+++ b/bir/src/main/kotlin/gay/pizza/pork/bir/IrSymbolGraphEdge.kt
@@ -0,0 +1,6 @@
+package gay.pizza.pork.bir
+
+import kotlinx.serialization.Serializable
+
+@Serializable
+data class IrSymbolGraphEdge(val user: IrSymbolUser, val owner: IrSymbolOwner)
diff --git a/bir/src/main/kotlin/gay/pizza/pork/bir/IrSymbolGraphSerializer.kt b/bir/src/main/kotlin/gay/pizza/pork/bir/IrSymbolGraphSerializer.kt
new file mode 100644
index 0000000..89ebab2
--- /dev/null
+++ b/bir/src/main/kotlin/gay/pizza/pork/bir/IrSymbolGraphSerializer.kt
@@ -0,0 +1,26 @@
+package gay.pizza.pork.bir
+
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.builtins.ListSerializer
+import kotlinx.serialization.descriptors.SerialDescriptor
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+
+class IrSymbolGraphSerializer : KSerializer<IrSymbolGraph> {
+  private val serializer = ListSerializer(IrSymbolGraphEdge.serializer())
+  override val descriptor: SerialDescriptor = serializer.descriptor
+
+  override fun deserialize(decoder: Decoder): IrSymbolGraph {
+    val graph = IrSymbolGraph()
+    graph.buildFromEdges(serializer.deserialize(decoder))
+    return graph
+  }
+
+  override fun serialize(encoder: Encoder, value: IrSymbolGraph) {
+    val edges = mutableListOf<IrSymbolGraphEdge>()
+    value.forEachEdge { user, owner ->
+      edges.add(IrSymbolGraphEdge(user, owner))
+    }
+    serializer.serialize(encoder, edges)
+  }
+}
diff --git a/bir/src/main/kotlin/gay/pizza/pork/bir/IrSymbolOwner.kt b/bir/src/main/kotlin/gay/pizza/pork/bir/IrSymbolOwner.kt
index 8d307fb..5049bb0 100644
--- a/bir/src/main/kotlin/gay/pizza/pork/bir/IrSymbolOwner.kt
+++ b/bir/src/main/kotlin/gay/pizza/pork/bir/IrSymbolOwner.kt
@@ -3,6 +3,6 @@ package gay.pizza.pork.bir
 import kotlinx.serialization.Serializable
 
 @Serializable
-sealed interface IrSymbolOwner : IrElement {
-  val symbol: IrSymbol
+sealed interface IrSymbolOwner {
+  var symbol: IrSymbol
 }
diff --git a/bir/src/main/kotlin/gay/pizza/pork/bir/IrSymbolTag.kt b/bir/src/main/kotlin/gay/pizza/pork/bir/IrSymbolTag.kt
index 78e2e6c..a68006e 100644
--- a/bir/src/main/kotlin/gay/pizza/pork/bir/IrSymbolTag.kt
+++ b/bir/src/main/kotlin/gay/pizza/pork/bir/IrSymbolTag.kt
@@ -4,6 +4,7 @@ import kotlinx.serialization.Serializable
 
 @Serializable
 enum class IrSymbolTag {
+  Slab,
   Function,
   Variable,
   Local,
diff --git a/bir/src/main/kotlin/gay/pizza/pork/bir/IrSymbolUser.kt b/bir/src/main/kotlin/gay/pizza/pork/bir/IrSymbolUser.kt
index 98ede87..ff880b7 100644
--- a/bir/src/main/kotlin/gay/pizza/pork/bir/IrSymbolUser.kt
+++ b/bir/src/main/kotlin/gay/pizza/pork/bir/IrSymbolUser.kt
@@ -3,6 +3,6 @@ package gay.pizza.pork.bir
 import kotlinx.serialization.Serializable
 
 @Serializable
-sealed interface IrSymbolUser : IrElement {
-  val target: IrSymbol
+sealed interface IrSymbolUser {
+  var target: IrSymbol
 }
diff --git a/bir/src/main/kotlin/gay/pizza/pork/bir/IrWorld.kt b/bir/src/main/kotlin/gay/pizza/pork/bir/IrWorld.kt
index 0b860bc..7d982c1 100644
--- a/bir/src/main/kotlin/gay/pizza/pork/bir/IrWorld.kt
+++ b/bir/src/main/kotlin/gay/pizza/pork/bir/IrWorld.kt
@@ -3,7 +3,7 @@ package gay.pizza.pork.bir
 import kotlinx.serialization.Serializable
 
 @Serializable
-data class IrWorld(val slabs: List<IrSlab>) : IrElement {
+data class IrWorld(var slabs: List<IrSlab>) : IrElement() {
   override fun crawl(block: (IrElement) -> Unit) {
     slabs.forEach(block)
   }
diff --git a/compiler/src/main/kotlin/gay/pizza/pork/compiler/IrCodeEmitter.kt b/compiler/src/main/kotlin/gay/pizza/pork/compiler/AstIrEmitter.kt
similarity index 99%
rename from compiler/src/main/kotlin/gay/pizza/pork/compiler/IrCodeEmitter.kt
rename to compiler/src/main/kotlin/gay/pizza/pork/compiler/AstIrEmitter.kt
index 579ad59..59969f0 100644
--- a/compiler/src/main/kotlin/gay/pizza/pork/compiler/IrCodeEmitter.kt
+++ b/compiler/src/main/kotlin/gay/pizza/pork/compiler/AstIrEmitter.kt
@@ -6,7 +6,7 @@ import gay.pizza.pork.bir.*
 import gay.pizza.pork.frontend.scope.ScopeSymbol
 import gay.pizza.pork.frontend.scope.SlabScope
 
-class IrCodeEmitter(
+class AstIrEmitter(
   val self: IrSymbol,
   val irSymbolWorld: IrSymbolWorld<Any>,
   val irSymbolAssignment: IrSymbolAssignment,
diff --git a/compiler/src/main/kotlin/gay/pizza/pork/compiler/CompilableSlab.kt b/compiler/src/main/kotlin/gay/pizza/pork/compiler/CompilableSlab.kt
index 36aade8..1217517 100644
--- a/compiler/src/main/kotlin/gay/pizza/pork/compiler/CompilableSlab.kt
+++ b/compiler/src/main/kotlin/gay/pizza/pork/compiler/CompilableSlab.kt
@@ -4,6 +4,7 @@ import gay.pizza.pork.ast.gen.Symbol
 import gay.pizza.pork.bir.IrDefinition
 import gay.pizza.pork.bir.IrSlab
 import gay.pizza.pork.bir.IrSlabLocation
+import gay.pizza.pork.bir.IrSymbolTag
 import gay.pizza.pork.frontend.Slab
 
 class CompilableSlab(val compiler: Compiler, val slab: Slab) {
@@ -20,11 +21,12 @@ class CompilableSlab(val compiler: Compiler, val slab: Slab) {
   }
 
   private fun compileIrSlab(): IrSlab {
+    val slabSymbol = compiler.irSymbolAssignment.next(IrSymbolTag.Slab, slab.location.commonLocationIdentity)
     val definitions = mutableListOf<IrDefinition>()
     for (compilableSymbol in compilableSymbols) {
       definitions.add(compilableSymbol.compiledIrDefinition)
     }
     val irSlabLocation = IrSlabLocation(slab.location.form, slab.location.filePath)
-    return IrSlab(irSlabLocation, definitions)
+    return IrSlab(slabSymbol, irSlabLocation, definitions)
   }
 }
diff --git a/compiler/src/main/kotlin/gay/pizza/pork/compiler/CompilableSymbol.kt b/compiler/src/main/kotlin/gay/pizza/pork/compiler/CompilableSymbol.kt
index 797e17d..d27fabb 100644
--- a/compiler/src/main/kotlin/gay/pizza/pork/compiler/CompilableSymbol.kt
+++ b/compiler/src/main/kotlin/gay/pizza/pork/compiler/CompilableSymbol.kt
@@ -29,7 +29,7 @@ class CompilableSymbol(val compilableSlab: CompilableSlab, val scopeSymbol: Scop
   private fun compileIrDefinition(): IrDefinition {
     val compiler = compilableSlab.compiler
     val functionSymbol = compiler.irSymbolWorld.create(scopeSymbol, IrSymbolTag.Function, scopeSymbol.symbol.id)
-    val irCodeEmitter = IrCodeEmitter(
+    val irCodeEmitter = AstIrEmitter(
       self = functionSymbol,
       irSymbolWorld = compiler.irSymbolWorld,
       irSymbolAssignment = compiler.irSymbolAssignment,
diff --git a/tool/src/main/kotlin/gay/pizza/pork/tool/CompileCommand.kt b/tool/src/main/kotlin/gay/pizza/pork/tool/CompileCommand.kt
index 1bb892e..085f722 100644
--- a/tool/src/main/kotlin/gay/pizza/pork/tool/CompileCommand.kt
+++ b/tool/src/main/kotlin/gay/pizza/pork/tool/CompileCommand.kt
@@ -4,16 +4,26 @@ import com.charleskorn.kaml.PolymorphismStyle
 import com.charleskorn.kaml.Yaml
 import com.github.ajalt.clikt.core.CliktCommand
 import com.github.ajalt.clikt.parameters.arguments.argument
+import com.github.ajalt.clikt.parameters.options.flag
+import com.github.ajalt.clikt.parameters.options.option
 import gay.pizza.dough.fs.PlatformFsProvider
 import gay.pizza.pork.ast.gen.Symbol
+import gay.pizza.pork.bir.IrSymbolGraph
 import gay.pizza.pork.bir.IrWorld
 import gay.pizza.pork.bytecode.CompiledWorld
 import gay.pizza.pork.compiler.Compiler
 import gay.pizza.pork.minimal.FileTool
 
-class CompileCommand : CliktCommand(help = "Compile Pork to Bytecode", name = "compile") {
+class CompileCommand : CliktCommand(help = "Compile Pork", name = "compile") {
+  val showIrCode by option("--show-ir-code").flag(default = false)
+  val showIrSymbolGraph by option("--show-ir-symbol-graph").flag(default = false)
+
   val path by argument("file")
 
+  private val yaml = Yaml(configuration = Yaml.default.configuration.copy(
+    polymorphismStyle = PolymorphismStyle.Property
+  ))
+
   override fun run() {
     val tool = FileTool(PlatformFsProvider.resolve(path))
     val world = tool.buildWorld()
@@ -22,16 +32,22 @@ class CompileCommand : CliktCommand(help = "Compile Pork to Bytecode", name = "c
     val compiledSlab = compiler.compilableSlabs.of(slab)
     val compiledMain = compiledSlab.resolve(Symbol("main"))
       ?: throw RuntimeException("'main' function not found.")
-    val compiledWorld = compiler.compile(compiledMain)
     val irWorld = compiler.compileIrWorld()
-    printCompiledIr(irWorld)
+    val compiledWorld = compiler.compile(compiledMain)
+    if (showIrCode) {
+      printCompiledIr(irWorld)
+    }
+
+    if (showIrSymbolGraph) {
+      val irSymbolGraph = IrSymbolGraph()
+      irSymbolGraph.buildFromRoot(irWorld)
+      println(yaml.encodeToString(IrSymbolGraph.serializer(), irSymbolGraph))
+    }
+
     printCompiledWorld(compiledWorld)
   }
 
   private fun printCompiledIr(irWorld: IrWorld) {
-    val yaml = Yaml(configuration = Yaml.default.configuration.copy(
-      polymorphismStyle = PolymorphismStyle.Property
-    ))
     println(yaml.encodeToString(IrWorld.serializer(), irWorld))
   }