Hi folks! This is my first time posting here, so please let me know if I should ask this question somewhere else instead. I'm asking here because https://github.com/v8/v8 does not have GitHub issues enabled.
In short, I have a project that embeds V8 and uses a single `Isolate` from multiple threads. The program runs just fine, but sometimes the inspector doesn't stop on the correct line after stepping over a statement that switches threads behind the scenes, even though the original thread is restored by the time the next statement is executed. >From what I can tell, the key information that controls this behavior is `thread_local_.target_frame_count_`, first set here <https://github.com/v8/v8/blob/3928133c96c7e7e785b66b59d2a13f24d624ed75/src/debug/debug.cc#L968>, and then checked here <https://github.com/v8/v8/blob/3928133c96c7e7e785b66b59d2a13f24d624ed75/src/debug/debug.cc#L412> . That check fails because `target_frame_count === -1`, which suggests it has not been updated since it was last initialized here <https://github.com/v8/v8/blob/3928133c96c7e7e785b66b59d2a13f24d624ed75/src/debug/debug.cc#L251> . Digging a bit deeper, I realized that the `Debug::ArchiveDebug` and `Debug::RestoreDebug` methods, which should be responsible for saving/restoring this `ThreadLocal` information when switching threads, currently don't do anything <https://github.com/v8/v8/blob/3928133c96c7e7e785b66b59d2a13f24d624ed75/src/debug/debug.cc#L263-L274> . I can understand that throwing away debugger state when switching threads might be OK if no one needs to debug a multi-threaded V8 program, but I think I've found a legitimate use case for preserving that state, so I would like to submit a PR to fix this. The essence of the PR would be: char* Debug::ArchiveDebug(char* storage) { MemCopy(storage, reinterpret_cast<char*>(&thread_local_), ArchiveSpacePerThread()); return storage + ArchiveSpacePerThread(); } char* Debug::RestoreDebug(char* storage) { MemCopy(reinterpret_cast<char*>(&thread_local_), storage, ArchiveSpacePerThread()); return storage + ArchiveSpacePerThread(); } int Debug::ArchiveSpacePerThread() { return sizeof(ThreadLocal); } Would this be a welcome PR? Is there anyone in particular I should ask to review this? Any other advice for a first-time contributor? Thanks, Ben -- -- v8-users mailing list [email protected] http://groups.google.com/group/v8-users --- You received this message because you are subscribed to the Google Groups "v8-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
