Rewrote enum lowering to support usage from other modules.

- Split up enum lowering into two stages: descriptors creation and IR creation.
- Added link stage test.
- Enum.valueOf() uses binary search instead of linear.

backend.native/tests/build.gradle

@@ -349,12 +349,12 @@ task enum1(type: RunKonanTest) {
 }
 
 task enum_valueOf(type: RunKonanTest) {
-    goldValue = "E1\n"
+    goldValue = "E1\nE2\nE3\n"
     source = "codegen/enum/valueOf.kt"
 }
 
 task enum_values(type: RunKonanTest) {
-    goldValue = "E2\n"
+    goldValue = "E3\nE1\nE2\n"
     source = "codegen/enum/values.kt"
 }
 
@@ -383,6 +383,12 @@ task enum_interfaceCallWithEntryClass(type: RunKonanTest) {
     source = "codegen/enum/interfaceCallWithEntryClass.kt"
 }
 
+task enum_linkTest(type: LinkKonanTest) {
+    goldValue = "42\n117\n-1\n"
+    source = "codegen/enum/linkTest_main.kt"
+    lib = "codegen/enum/linkTest_lib.kt"
+}
+
 task innerClass_simple(type: RunKonanTest) {
     goldValue = "OK\n"
     source = "codegen/innerClass/simple.kt"

backend.native/tests/codegen/enum/linkTest_lib.kt

@@ -0,0 +1,7 @@
+package a
+
+enum class A(val x: Int) {
+    Z1(42),
+    Z2(117),
+    Z3(-1)
+}

backend.native/tests/codegen/enum/linkTest_main.kt

@@ -0,0 +1,7 @@
+import a.*
+
+fun main(args: Array<String>) {
+    println(A.Z1.x)
+    println(A.valueOf("Z2").x)
+    println(A.values()[2].x)
+}

backend.native/tests/codegen/enum/valueOf.kt

@@ -1,8 +1,11 @@
 enum class E {
+    E3,
     E1,
     E2
 }
 
 fun main(args: Array<String>) {
     println(E.valueOf("E1").toString())
+    println(E.valueOf("E2").toString())
+    println(E.valueOf("E3").toString())
 }

backend.native/tests/codegen/enum/values.kt

@@ -1,8 +1,11 @@
 enum class E {
+    E3,
     E1,
     E2
 }
 
 fun main(args: Array<String>) {
+    println(E.values()[0].toString())
     println(E.values()[1].toString())
+    println(E.values()[2].toString())
 }