Swift SIL: add Builder.createUnreachable()

Author: eeckstein

SwiftCompilerSources/Sources/SIL/Builder.swift

@@ -187,4 +187,12 @@ public struct Builder {
       return bi.getAs(BranchInst.self)
     }
   }
+
+  @discardableResult
+  public func createUnreachable() -> UnreachableInst {
+    notifyInstructionsChanged()
+    notifyBranchesChanged()
+    let ui = SILBuilder_createUnreachable(bridged)
+    return ui.getAs(UnreachableInst.self)
+  }
 }

include/swift/SIL/SILBridging.h

@@ -456,6 +456,7 @@ BridgedInstruction SILBuilder_createUncheckedEnumData(BridgedBuilder builder,
 BridgedInstruction SILBuilder_createBranch(
           BridgedBuilder builder, BridgedBasicBlock destBlock,
           BridgedValueArray arguments);
+BridgedInstruction SILBuilder_createUnreachable(BridgedBuilder builder);
 
 SWIFT_END_NULLABILITY_ANNOTATIONS
 

lib/SIL/Utils/SILBridging.cpp

@@ -1184,3 +1184,9 @@ BridgedInstruction SILBuilder_createBranch(
                                castToBasicBlock(destBlock),
                                getSILValues(arguments, argValues))};
 }
+
+BridgedInstruction SILBuilder_createUnreachable(BridgedBuilder b) {
+  SILBuilder builder(castToInst(b.insertBefore), castToBasicBlock(b.insertAtEnd),
+                     b.loc.getScope());
+  return {builder.createUnreachable(RegularLocation(b.loc.getLocation()))};
+}