Refactor delete_program_space as a destructor

Currently, while the program_space's ctor adds the new pspace to the
pspaces list, the destructor doesn't remove the pspace from the pspace
list.  Instead, you're supposed to use delete_program_space, to both
remove the pspace from the list, and deleting the pspace.

This patch eliminates delete_program_space, and makes the pspace dtor
remove the deleted pspace from the pspace list itself, i.e., makes the
dtor do the mirror opposite of the ctor.

I found this helps with a following patch that will allocate a mock
program_space on the stack.  It's easier to just let the regular dtor
remove the mock pspace from the pspace list than arrange to call
delete_program_space instead of the pspace dtor in that situation.

While at it, move the ctor/dtor intro comments to the header file, and
make the ctor explicit.

gdb/ChangeLog:
2020-04-16  Pedro Alves  <palves@redhat.com>

	* inferior.c (delete_inferior): Use delete operator directly
	instead of delete_program_space.
	* progspace.c (add_program_space): New, factored out from
	program_space::program_space.
	(remove_program_space): New, factored out from
	delete_program_space.
	(program_space::program_space): Remove intro comment.  Rewrite.
	(program_space::~program_space): Remove intro comment.  Call
	remove_program_space.
	(delete_program_space): Delete.
	* progspace.h (program_space::program_space): Make explicit.  Move
	intro comment here, adjusted.
	(program_space::~program_space): Move intro comment here,
	adjusted.
	(delete_program_space): Remove.

1 files changed, 9 insertions, 5 deletions

diff --git a/gdb/progspace.h b/gdb/progspace.h
index 71a6f28..2b88784 100644
--- a/gdb/progspace.h
+++ b/gdb/progspace.h
@@ -209,7 +209,15 @@ private:
 
 struct program_space
 {
-  program_space (address_space *aspace_);
+  /* Constructs a new empty program space, binds it to ASPACE, and
+     adds it to the program space list.  */
+  explicit program_space (address_space *aspace);
+
+  /* Releases a program space, and all its contents (shared libraries,
+     objfiles, and any other references to the program space in other
+     modules).  It is an internal error to call this when the program
+     space is the current program space, since there should always be
+     a program space.  */
   ~program_space ();
 
   typedef unwrapping_objfile_range objfiles_range;
@@ -362,10 +370,6 @@ extern struct program_space *current_program_space;
 #define ALL_PSPACES(pspace) \
   for ((pspace) = program_spaces; (pspace) != NULL; (pspace) = (pspace)->next)
 
-/* Remove a program space from the program spaces list and release it.  It is
-   an error to call this function while PSPACE is the current program space. */
-extern void delete_program_space (struct program_space *pspace);
-
 /* Returns the number of program spaces listed.  */
 extern int number_of_program_spaces (void);