gdb: fix darwin-nat.c build / adapt to multi-target

The darwin-nat.c file doesn't build since the multi-target changes
(5b6d1e4f, "Multi-target support").  This patch makes it build.  I have
access to a macOS vm, so I am able to build it, but I wasn't able to
successfully codesign it and try to actually debug something, so I don't
know if it works.  I don't have much more time to put on this to figure
it out, so I thought I'd sent the patch anyway, as it's at least a step
in the right direction.

The bulk of the patch is to change a bunch of functions to be methods of
the darwin_nat_target object, so that this can pass `this` to
find_inferior_ptid and other functions that now require a
process_stratum_target pointer.

The darwin_ptrace_him function (renamed to darwin_nat_target::ptrace_him
in this patch) is passed to fork_inferior as the `init_trace_fun`
parameter.  Since the method can't be passed as a plain function pointer
(we need the `this` pointer), I changed the `init_trace_fun` parameter
of fork_inferior to be a gdb::function_view, so we can pass a lambda and
capture `this`.

The changes in darwin-nat.h are only to move definition higher in the
file, so that forward declarations are not needed.

gdb/ChangeLog:

	* darwin-nat.h (struct darwin_exception_msg, enum
	darwin_msg_state, struct darwin_thread_info, darwin_thread_t):
	Move up.
	(class darwin_nat_target) <wait_1, check_new_threads,
	decode_exception_message, decode_message, stop_inferior,
	init_thread_list, ptrace_him, cancel_breakpoint>: Declare.
	* darwin-nat.c (darwin_check_new_threads): Rename to...
	(darwin_nat_target::check_new_threads): ... this.
	(darwin_suspend_inferior_it): Remove.
	(darwin_decode_exception_message): Rename to...
	(darwin_nat_target::decode_exception_message): ... this.
	(darwin_nat_target::resume): Pass target to find_inferior_ptid.
	(darwin_decode_message): Rename to...
	(darwin_nat_target::decode_message): ... this.
	(cancel_breakpoint): Rename to...
	(darwin_nat_target::cancel_breakpoint): ... this.
	(darwin_wait): Rename to...
	(darwin_nat_target::wait_1): ... this.  Use range-based for loop
	instead of iterate_over_inferiors.
	(darwin_nat_target::wait): Call wait_1 instead of darwin_wait.
	(darwin_stop_inferior): Rename to...
	(darwin_nat_target::stop_inferior): ... this.
	(darwin_nat_target::kill): Call wait_1 instead of darwin_wait.
	(darwin_init_thread_list): Rename to...
	(darwin_nat_target::init_thread_list): ... this.
	(darwin_ptrace_him): Rename to...
	(darwin_nat_target::ptrace_him): ... this.
	(darwin_nat_target::create_inferior): Pass lambda function to
	fork_inferior.
	(darwin_nat_target::detach): Call stop_inferior instead of
	darwin_stop_inferior.
	* fork-inferior.h (fork_inferior): Change init_trace_fun
	parameter to gdb::function_view.
	* fork-inferior.c (fork_inferior): Likewise.

1 files changed, 68 insertions, 53 deletions

diff --git a/gdb/darwin-nat.h b/gdb/darwin-nat.h
index 5d2f30d..86bb338 100644
--- a/gdb/darwin-nat.h
+++ b/gdb/darwin-nat.h
@@ -21,6 +21,59 @@
 #include <mach/mach.h>
 #include "gdbthread.h"
 
+struct darwin_exception_msg
+{
+  mach_msg_header_t header;
+
+  /* Thread and task taking the exception.  */
+  mach_port_t thread_port;
+  mach_port_t task_port;
+
+  /* Type of the exception.  */
+  exception_type_t ex_type;
+
+  /* Machine dependent details.  */
+  mach_msg_type_number_t data_count;
+  integer_t ex_data[2];
+};
+
+enum darwin_msg_state
+{
+  /* The thread is running.  */
+  DARWIN_RUNNING,
+
+  /* The thread is stopped.  */
+  DARWIN_STOPPED,
+
+  /* The thread has sent a message and waits for a reply.  */
+  DARWIN_MESSAGE
+};
+
+struct darwin_thread_info : public private_thread_info
+{
+  /* The thread port from a GDB point of view.  */
+  thread_t gdb_port = 0;
+
+  /* The thread port from the inferior point of view.  Not to be used inside
+     gdb except for get_ada_task_ptid.  */
+  thread_t inf_port = 0;
+
+  /* Current message state.
+     If the kernel has sent a message it expects a reply and the inferior
+     can't be killed before.  */
+  enum darwin_msg_state msg_state = DARWIN_RUNNING;
+
+  /* True if this thread is single-stepped.  */
+  bool single_step = false;
+
+  /* True if a signal was manually sent to the thread.  */
+  bool signaled = false;
+
+  /* The last exception received.  */
+  struct darwin_exception_msg event {};
+};
+typedef struct darwin_thread_info darwin_thread_t;
+
 /* This needs to be overridden by the platform specific nat code.  */
 
 class darwin_nat_target : public inf_child_target
@@ -59,6 +112,21 @@ class darwin_nat_target : public inf_child_target
   bool supports_multi_process () override;
 
   ptid_t get_ada_task_ptid (long lwp, long thread) override;
+
+private:
+  ptid_t wait_1 (ptid_t, struct target_waitstatus *);
+  void check_new_threads (inferior *inf);
+  int decode_exception_message (mach_msg_header_t *hdr,
+			        inferior **pinf,
+				darwin_thread_t **pthread);
+  ptid_t decode_message (mach_msg_header_t *hdr,
+			 darwin_thread_t **pthread,
+			 inferior **pinf,
+			 target_waitstatus *status);
+  void stop_inferior (inferior *inf);
+  void init_thread_list (inferior *inf);
+  void ptrace_him (int pid);
+  int cancel_breakpoint (ptid_t ptid);
 };
 
 /* Describe the mach exception handling state for a task.  This state is saved
@@ -83,59 +151,6 @@ struct darwin_exception_info
   mach_msg_type_number_t count = 0;
 };
 
-struct darwin_exception_msg
-{
-  mach_msg_header_t header;
-
-  /* Thread and task taking the exception.  */
-  mach_port_t thread_port;
-  mach_port_t task_port;
-
-  /* Type of the exception.  */
-  exception_type_t ex_type;
-
-  /* Machine dependent details.  */
-  mach_msg_type_number_t data_count;
-  integer_t ex_data[2];
-};
-
-enum darwin_msg_state
-{
-  /* The thread is running.  */
-  DARWIN_RUNNING,
-
-  /* The thread is stopped.  */
-  DARWIN_STOPPED,
-
-  /* The thread has sent a message and waits for a reply.  */
-  DARWIN_MESSAGE
-};
-
-struct darwin_thread_info : public private_thread_info
-{
-  /* The thread port from a GDB point of view.  */
-  thread_t gdb_port = 0;
-
-  /* The thread port from the inferior point of view.  Not to be used inside
-     gdb except for get_ada_task_ptid.  */
-  thread_t inf_port = 0;
-
-  /* Current message state.
-     If the kernel has sent a message it expects a reply and the inferior
-     can't be killed before.  */
-  enum darwin_msg_state msg_state = DARWIN_RUNNING;
-
-  /* True if this thread is single-stepped.  */
-  bool single_step = false;
-
-  /* True if a signal was manually sent to the thread.  */
-  bool signaled = false;
-
-  /* The last exception received.  */
-  struct darwin_exception_msg event {};
-};
-typedef struct darwin_thread_info darwin_thread_t;
-
 static inline darwin_thread_info *
 get_darwin_thread_info (class thread_info *thread)
 {