From 200fd2874d2c147539f756b29e15ebbafa81dfcf Mon Sep 17 00:00:00 2001 From: Andrew Burgess Date: Fri, 12 Nov 2021 11:18:58 +0000 Subject: gdb: make post_startup_inferior a virtual method on inf_ptrace_target While working on a later patch that required me to understand how GDB starts up inferiors, I was confused by the target_ops::post_startup_inferior method. The post_startup_inferior target function is only called from inf_ptrace_target::create_inferior. Part of the target class hierarchy looks like this: inf_child_target | '-- inf_ptrace_target | |-- linux_nat_target | |-- fbsd_nat_target | |-- nbsd_nat_target | |-- obsd_nat_target | '-- rs6000_nat_target Every sub-class of inf_ptrace_target, except rs6000_nat_target, implements ::post_startup_inferior. The rs6000_nat_target picks up the implementation of ::post_startup_inferior not from inf_ptrace_target, but from inf_child_target. No descendent of inf_child_target, outside the inf_ptrace_target sub-tree, implements ::post_startup_inferior, which isn't really surprising, as they would never see the method called (remember, the method is only called from inf_ptrace_target::create_inferior). What I find confusing is the role inf_child_target plays in implementing, what is really a helper function for just one of its descendents. In this commit I propose that we formally make ::post_startup_inferior a helper function of inf_ptrace_target. To do this I will remove the ::post_startup_inferior from the target_ops API, and instead make this a protected, pure virtual function on inf_ptrace_target. I'll remove the empty implementation of ::post_startup_inferior from the inf_child_target class, and add a new empty implementation to the rs6000_nat_target class. All the other descendents of inf_ptrace_target already provide an implementation of this method and so don't need to change beyond making the method protected within their class declarations. To me, this makes much more sense now. The helper function, which is only called from within the inf_ptrace_target class, is now a part of the inf_ptrace_target class. The only way in which this change is visible to a user is if the user turns on 'set debug target 1'. With this debug flag on, prior to this patch the user would see something like: -> native->post_startup_inferior (...) <- native->post_startup_inferior (2588939) After this patch these lines are no longer present, as the post_startup_inferior is no longer a top level target method. For me, this is an acceptable change. --- gdb/netbsd-nat.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'gdb/netbsd-nat.h') diff --git a/gdb/netbsd-nat.h b/gdb/netbsd-nat.h index 43d60eb..ad83f20 100644 --- a/gdb/netbsd-nat.h +++ b/gdb/netbsd-nat.h @@ -32,7 +32,6 @@ struct nbsd_nat_target : public inf_ptrace_target bool thread_alive (ptid_t ptid) override; const char *thread_name (struct thread_info *thr) override; - void post_startup_inferior (ptid_t ptid) override; void post_attach (int pid) override; void update_thread_list () override; std::string pid_to_str (ptid_t ptid) override; @@ -57,6 +56,9 @@ struct nbsd_nat_target : public inf_ptrace_target ULONGEST *xfered_len) override; bool supports_dumpcore () override; void dumpcore (const char *filename) override; + +protected: + void post_startup_inferior (ptid_t ptid) override; }; #endif /* netbsd-nat.h */ -- cgit v1.1