| We build an equivalent of the jacoco-agent.jar which contains classes from org.jacoco.core, |
| org.jacoco.agent and org.jacoco.agent.rt packages but also classes from asm 5.0.1. |
| |
| However, Jacoco depends on classes that do not exist in Android (java.lang.instrument.* or |
| javax.management.*) for runtime instrumentation only. The ART compiler would reject those classes |
| when they are either in the bootclasspath (core, frameworks, ...) or system apps. |
| |
| Since we only use offline instrumentation for code coverage (using Jack) and do not execute these |
| classes at runtime, we simply not compile them here. |
| |
| We also need to modify the source code to cut dependencies to the classes that we exclude from the |
| compilation. The changes are surrounded by "BEGIN android-change" and "END android-change". Here |
| is the list of the changes: |
| |
| 1) Remove the creation of JmxRegistration in org.jacoco.agent.rt.internal.Agent. |
| 2) Change default OutputMode to none in org.jacoco.core.runtime.AgentOptions |
| 3) Change the runtime to reduce dependencies on core libraries. |
| Previously, Offline's static initializer would eagerly create an |
| Agent, a process which has lots of dependencies. With this change, |
| Offline only eagerly creates a Map<Long, ExecutionData>, which is much |
| more lightweight. The Agent is only created when it's actually |
| needed. This makes it possible to instrument a lot of more core |
| libraries without creating a circular dependency at runtime. |
| 4) Disable use of 'constant dynamic' bytecode in |
| org.jacoco.core.internal.instr.ProbeArrayStrategyFactory, because R8/D8 doesn't support it. |
| (https://issuetracker.google.com/178172809) |
