New Kotlin IR Compiler Backend breaks generated code filter

[Grisu118]

Jacoco 0.8.2 introduced filtering of generated methods in kotlin (#689).

When I use the kotlin 1.4.0 with the new IR Compiler Backend, the filters do not work. You find below the example from above pull request updated to kotlin 1.4.0. With a comment where you can enable / disable the new compiler backend.

Steps to reproduce

• JaCoCo version: 0.8.5

• Operating system: Windows 10

• Tool integration: Gradle 6.6

• Complete executable reproducer: example.zip

• Steps: gradlew clean jacocoTestReport

Expected behaviour

Generated methods are excluded, like with useIR = false

Actual behaviour

Generated methods are not excluded, with useIR = true

[Godin]

@Grisu118 if there is a change in the bytecode generated by Kotlin compiler, then why don't you report this to developers of compiler ? 😉 CC @qwwdfsad @Alefas @antonarhipov

---

For example for DataClass.kt

data class DataClass(var x: Int)

after execution of kotlin-compiler-1.4.0/bin/kotlinc -Xuse-ir DataClass.kt
execution of javap -v -p DataClass.class
shows that generated methods have LineNumberTable

  public int hashCode();
    descriptor: ()I
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
         0: aload_0
         1: getfield      #13                 // Field x:I
         4: ireturn
      LineNumberTable:
        line 1: 0
      LocalVariableTable:
        Start  Length  Slot  Name   Signature
            0       5     0  this   LDataClass;

which was not the case before and is not the case in the absence of -Xuse-ir,
what breaks #689 implemented by one of compiler developers @goodwinnk at that time

---

Using our validation tests one can observe other changes in how the Kotlin compiler generates bytecode:

--- c/org.jacoco.core.test.validation.kotlin/pom.xml
+++ w/org.jacoco.core.test.validation.kotlin/pom.xml
@@ -26,7 +26,7 @@

   <properties>
     <bytecode.version>6</bytecode.version>
-    <kotlin.version>1.3.61</kotlin.version>
+    <kotlin.version>1.4.0</kotlin.version>
   </properties>

   <dependencies>
@@ -43,7 +43,7 @@
     <dependency>
       <groupId>org.jetbrains.kotlinx</groupId>
       <artifactId>kotlinx-coroutines-core</artifactId>
-      <version>1.0.1</version>
+      <version>1.3.9</version>
     </dependency>
   </dependencies>

@@ -60,6 +60,11 @@
             <goals>
               <goal>compile</goal>
             </goals>
+            <configuration>
+              <args>
+                <arg>-Xuse-ir</arg>
+              </args>
+            </configuration>
           </execution>
         </executions>
       </plugin>

[qwwdfsad]

I'll investigate it on our side

[qwwdfsad]

We'll consider it a bug for now: https://youtrack.jetbrains.com/issue/KT-41903

Also, we (again) discussed a potential solution for coverage and bytecode processing tools and decided to experiment with @kotlin.Generated (https://youtrack.jetbrains.com/issue/KT-41906) to have a consistent marker for most of the autogenerated members

[Godin]

@qwwdfsad first of all thanks a lot! ❤️

We'll consider it a bug for now: https://youtrack.jetbrains.com/issue/KT-41903

As of today title is "JVM IR: do not generate LineNumberTable in auto-generated members of data classes",
however quoting #1086 (comment)

Using our validation tests one can observe other changes in how the Kotlin compiler generates bytecode

😉 for another example for the following DelegatedList.kt that is not about data classes

class DelegatedList : List<Int> by ArrayList()

execution of

kotlin-compiler-1.4.10/bin/kotlinc DelegatedList.kt \
    && javap -v -p DelegatedList.class

shows

  public int getSize();
    descriptor: ()I
    flags: ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
         0: aload_0
         1: getfield      #20                 // Field $$delegate_0:Ljava/util/ArrayList;
         4: invokevirtual #30                 // Method java/util/ArrayList.size:()I
         7: ireturn
      LocalVariableTable:
        Start  Length  Slot  Name   Signature
            0       8     0  this   LDelegatedList;

but execution with -Xuse-ir

kotlin-compiler-1.4.10/bin/kotlinc -Xuse-ir DelegatedList.kt \
    && javap -v -p DelegatedList.class

shows that LineNumberTable appears

  public int getSize();
    descriptor: ()I
    flags: ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
         0: aload_0
         1: getfield      #20                 // Field $$delegate_0:Ljava/util/ArrayList;
         4: invokevirtual #99                 // Method java/util/ArrayList.size:()I
         7: ireturn
      LineNumberTable:
        line 1: 0
      LocalVariableTable:
        Start  Length  Slot  Name   Signature
            0       8     0  this   LDelegatedList;

[qwwdfsad]

Thanks, it is also being fixed :) https://youtrack.jetbrains.com/issue/KT-41960

[Godin]

After #1162, #1164, #1166, #1172, #1174, #1178 and #1181
our validation tests pass
with Kotlin compiler version 1.5.0 that uses new IR backend
as well as with Kotlin compiler version 1.4.32 with option -Xuse-ir
So I'm closing this ticket.