2009-10-19 Pedro Alves <pedro@codesourcery.com>

	    Stan Shebs	<stan@codesourcery.com>

	Add base multi-executable/process support to GDB.

	gdb/
	* Makefile.in (SFILES): Add progspace.c.
	(COMMON_OBS): Add progspace.o.
	* progspace.h: New.
	* progspace.c: New.

	* breakpoint.h (struct bp_target_info) <placed_address_space>: New
	field.
	(struct bp_location) <pspace>: New field.
	(struct breakpoint) <pspace>: New field.
	(bpstat_stop_status, breakpoint_here_p)
	(moribund_breakpoint_here_p, breakpoint_inserted_here_p)
	(regular_breakpoint_inserted_here_p)
	(software_breakpoint_inserted_here_p, breakpoint_thread_match)
	(set_default_breakpoint): Adjust prototypes.
	(remove_breakpoints_pid, breakpoint_program_space_exit): Declare.
	(insert_single_step_breakpoint, deprecated_insert_raw_breakpoint):
	Adjust prototypes.
	* breakpoint.c (executing_startup): Delete.
	(default_breakpoint_sspace): New.
	(breakpoint_restore_shadows): Skip if the address space doesn't
	match.
	(update_watchpoint): Record the frame's program space in the
	breakpoint location.
	(insert_bp_location): Record the address space in target_info.
	Adjust to pass the symbol space to solib_name_from_address.
	(breakpoint_program_space_exit): New.
	(insert_breakpoint_locations): Switch the symbol space and thread
	when inserting breakpoints.  Don't insert breakpoints in a vfork
	parent waiting for vfork done if we're not attached to the vfork
	child.
	(remove_breakpoints_pid): New.
	(reattach_breakpoints): Switch to a thread of PID.  Ignore
	breakpoints of other symbol spaces.
	(create_internal_breakpoint): Store the symbol space in the sal.
	(create_longjmp_master_breakpoint): Iterate over all symbol
	spaces.
	(update_breakpoints_after_exec): Ignore breakpoints for other
	symbol spaces.
	(remove_breakpoint): Rename to ...
	(remove_breakpoint_1): ... this.  Pass the breakpoints symbol
	space to solib_name_from_address.
	(remove_breakpoint): New.
	(mark_breakpoints_out): Ignore breakpoints from other symbol
	spaces.
	(breakpoint_init_inferior): Ditto.
	(breakpoint_here_p): Add an address space argument and adjust to
	use breakpoint_address_match.
	(moribund_breakpoint_here_p): Ditto.
	(regular_breakpoint_inserted_here_p): Ditto.
	(breakpoint_inserted_here_p): Ditto.
	(software_breakpoint_inserted_here_p): Ditto.
	(breakpoint_thread_match): Ditto.
	(bpstat_check_location): Ditto.
	(bpstat_stop_status): Ditto.
	(print_breakpoint_location): If there's a location to print,
	switch the current symbol space.
	(print_one_breakpoint_location): Add `allflag' argument.
	(print_one_breakpoint): Ditto.	Adjust.
	(do_captured_breakpoint_query): Adjust.
	(breakpoint_1): Adjust.
	(breakpoint_has_pc): Also match the symbol space.
	(describe_other_breakpoints): Add a symbol space argument and
	adjust.
	(set_default_breakpoint): Add a symbol space argument.	Set
	default_breakpoint_sspace.
	(breakpoint_address_match): New.
	(check_duplicates_for): Add an address space argument, and adjust.
	(set_raw_breakpoint): Record the symbol space in the location and
	in the breakpoint.
	(set_longjmp_breakpoint): Skip longjmp master breakpoints from
	other symbol spaces.
	(remove_thread_event_breakpoints, remove_solib_event_breakpoints)
	(disable_breakpoints_in_shlibs): Skip breakpoints from other
	symbol spaces.
	(disable_breakpoints_in_unloaded_shlib): Match symbol spaces.
	(create_catchpoint): Set the symbol space in the sal.
	(disable_breakpoints_before_startup): Skip breakpoints from other
	symbol spaces.	Set executing_startup in the current symbol space.
	(enable_breakpoints_after_startup): Clear executing_startup in the
	current symbol space.  Skip breakpoints from other symbol spaces.
	(clone_momentary_breakpoint): Also copy the symbol space.
	(add_location_to_breakpoint): Set the location's symbol space.
	(bp_loc_is_permanent): Switch thread and symbol space.
	(create_breakpoint): Adjust.
	(expand_line_sal_maybe): Expand comment to mention symbol spaces.
	Switch thread and symbol space when reading memory.
	(parse_breakpoint_sals): Set the symbol space in the sal.
	(break_command_really): Ditto.
	(skip_prologue_sal): Switch and space.
	(resolve_sal_pc): Ditto.
	(watch_command_1): Record the symbol space in the sal.
	(create_ada_exception_breakpoint): Adjust.
	(clear_command): Adjust.  Match symbol spaces.
	(update_global_location_list): Use breakpoint_address_match.
	(breakpoint_re_set_one): Switch thread and space.
	(breakpoint_re_set): Save symbol space.
	(breakpoint_re_set_thread): Also reset the symbol space.
	(deprecated_insert_raw_breakpoint): Add an address space argument.
	Adjust.
	(insert_single_step_breakpoint): Ditto.
	(single_step_breakpoint_inserted_here_p): Ditto.
	(clear_syscall_counts): New.
	(_initialize_breakpoint): Install it as inferior_exit observer.

	* exec.h: Include "progspace.h".
	(exec_bfd, exec_bfd_mtime): New defines.
	(exec_close): Declare.
	* exec.c: Include "gdbthread.h" and "progspace.h".
	(exec_bfd, exec_bfd_mtime, current_target_sections_1): Delete.
	(using_exec_ops): New.
	(exec_close_1): Rename to exec_close, and make public.
	(exec_close): Rename to exec_close_1, and adjust all callers.  Add
	description.  Remove target sections and close executables from
	all program spaces.
	(exec_file_attach): Add comment.
	(add_target_sections): Check on `using_exec_ops' to check if the
	target should be pushed.
	(remove_target_sections): Only unpush the target if there are no
	more target sections in any symbol space.
	* gdbcore.h: Include "exec.h".
	(exec_bfd, exec_bfd_mtime): Remove declarations.

	* frame.h (get_frame_program_space, get_frame_address_space)
	(frame_unwind_program_space): Declare.
	* frame.c (struct frame_info) <pspace, aspace>: New fields.
	(create_sentinel_frame): Add program space argument.  Set the
	pspace and aspace fields of the frame object.
	(get_current_frame, create_new_frame): Adjust.
	(get_frame_program_space): New.
	(frame_unwind_program_space): New.
	(get_frame_address_space): New.
	* stack.c (print_frame_info): Adjust.
	(print_frame): Use the frame's program space.

	* gdbthread.h (any_live_thread_of_process): Declare.
	* thread.c (any_live_thread_of_process): New.
	(switch_to_thread): Switch the program space as well.
	(restore_selected_frame): Don't warn if trying to restore frame
	level 0.

	* inferior.h: Include "progspace.h".
	(detach_fork): Declare.
	(struct inferior) <removable, aspace, pspace>
	<vfork_parent, vfork_child, pending_detach>
	<waiting_for_vfork_done>: New fields.
	<terminal_info>: Remove field.
	<data, num_data>: New fields.
	(register_inferior_data, register_inferior_data_with_cleanup)
	(clear_inferior_data, set_inferior_data, inferior_data): Declare.
	(exit_inferior, exit_inferior_silent, exit_inferior_num_silent)
	(inferior_appeared): Declare.
	(find_inferior_pid): Typo.
	(find_inferior_id, find_inferior_for_program_space): Declare.
	(set_current_inferior, save_current_inferior, prune_inferiors)
	(number_of_inferiors): Declare.
	(inferior_list): Declare.
	* inferior.c: Include "gdbcore.h" and "symfile.h".
	(inferior_list): Make public.
	(delete_inferior_1): Always delete thread silently.
	(find_inferior_id): Make public.
	(current_inferior_): New.
	(current_inferior): Use it.
	(set_current_inferior): New.
	(restore_inferior): New.
	(save_current_inferior): New.
	(free_inferior): Free the per-inferior data.
	(add_inferior_silent): Allocate per-inferior data.
	Call inferior_appeared.
	(delete_threads_of_inferior): New.
	(delete_inferior_1): Adjust interface to take an inferior pointer.
	(delete_inferior): Adjust.
	(delete_inferior_silent): Adjust.
	(exit_inferior_1): New.
	(exit_inferior): New.
	(exit_inferior_silent): New.
	(exit_inferior_num_silent): New.
	(detach_inferior): Adjust.
	(inferior_appeared): New.
	(discard_all_inferiors): Adjust.
	(find_inferior_id): Make public.  Assert pid is not zero.
	(find_inferior_for_program_space): New.
	(have_inferiors): Check if we have any inferior with pid not zero.
	(have_live_inferiors): Go over all pushed targets looking for
	process_stratum.
	(prune_inferiors): New.
	(number_of_inferiors): New.
	(print_inferior): Add executable column.  Print vfork parent/child
	relationships.
	(inferior_command): Adjust to cope with not running inferiors.
	(remove_inferior_command): New.
	(add_inferior_command): New.
	(clone_inferior_command): New.
	(struct inferior_data): New.
	(struct inferior_data_registration): New.
	(struct inferior_data_registry): New.
	(inferior_data_registry): New.
	(register_inferior_data_with_cleanup): New.
	(register_inferior_data): New.
	(inferior_alloc_data): New.
	(inferior_free_data): New.
	(clear_inferior_data): New.
	(set_inferior_data): New.
	(inferior_data): New.
	(initialize_inferiors): New.
	(_initialize_inferiors): Register "add-inferior",
	"remove-inferior" and "clone-inferior" commands.

	* objfiles.h: Include "progspace.h".
	(struct objfile) <pspace>: New field.
	(symfile_objfile, object_files): Don't declare.
	(ALL_PSPACE_OBJFILES): New.
	(ALL_PSPACE_OBJFILES_SAFE): New.
	(ALL_OBJFILES, ALL_OBJFILES_SAFE): Adjust.
	(ALL_PSPACE_SYMTABS): New.
	(ALL_PRIMARY_SYMTABS): Adjust.
	(ALL_PSPACE_PRIMARY_SYMTABS): New.
	(ALL_PSYMTABS): Adjust.
	(ALL_PSPACE_PSYMTABS): New.
	* objfiles.c (object_files, symfile_objfile): Delete.
	(struct objfile_sspace_info): New.
	(objfiles_pspace_data): New.
	(objfiles_pspace_data_cleanup): New.
	(get_objfile_pspace_data): New.
	(objfiles_changed_p): Delete.
	(allocate_objfile): Set the objfile's program space.  Adjust to
	reference objfiles_changed_p in pspace data.
	(free_objfile): Adjust to reference objfiles_changed_p in pspace
	data.
	(objfile_relocate): Ditto.
	(update_section_map): Add pspace argument.  Adjust to iterate over
	objfiles in the passed in pspace.
	(find_pc_section): Delete sections and num_sections statics.
	Adjust to refer to program space's objfiles_changed_p.	Adjust to
	refer to sections and num_sections store in the objfile's pspace
	data.
	(objfiles_changed): Adjust to reference objfiles_changed_p in
	pspace data.
	(_initialize_objfiles): New.
	* linespec.c (decode_all_digits, decode_dollar): Set the sal's
	program space.
	* source.c (current_source_pspace): New.
	(get_current_source_symtab_and_line): Set the sal's program space.
	(set_current_source_symtab_and_line): Set current_source_pspace.
	(select_source_symtab): Ditto.	Use ALL_OBJFILES.
	(forget_cached_source_info): Iterate over all program spaces.
	* symfile.c (clear_symtab_users): Adjust.
	* symmisc.c (print_symbol_bcache_statistics): Iterate over all
	program spaces.
	(print_objfile_statistics): Ditto.
	(maintenance_print_msymbols): Ditto.
	(maintenance_print_objfiles): Ditto.
	(maintenance_info_symtabs): Ditto.
	(maintenance_info_psymtabs): Ditto.
	* symtab.h (SYMTAB_PSPACE): New.
	(struct symtab_and_line) <pspace>: New field.
	* symtab.c (init_sal): Clear the sal's program space.
	(find_pc_sect_symtab): Set the sal's program space.  Switch thread
	and space.
	(append_expanded_sal): Add program space argument.  Iterate over
	all program spaces.
	(expand_line_sal): Iterate over all program spaces.  Switch
	program space.

	* target.h (enum target_waitkind) <TARGET_WAITKIND_VFORK_DONE>: New.
	(struct target_ops) <to_thread_address_space>: New field.
	(target_thread_address_space): Define.
	* target.c (target_detach): Only remove breakpoints from the
	inferior we're detaching.
	(target_thread_address_space): New.

	* defs.h (initialize_progspace): Declare.
	* top.c (gdb_init): Call it.

	* solist.h (struct so_list) <sspace>: New field.
	* solib.h (struct program_space): Forward declare.
	(solib_name_from_address): Adjust prototype.
	* solib.c (so_list_head): Replace with a macro referencing the
	program space.
	(update_solib_list): Set the so's program space.
	(solib_name_from_address): Add a program space argument and adjust.

	* solib-svr4.c (struct svr4_info) <pid>: Delete field.
	<interp_text_sect_low, interp_text_sect_high, interp_plt_sect_low>
	<interp_plt_sect_high>: New fields.
	(svr4_info_p, svr4_info): Delete.
	(solib_svr4_sspace_data): New.
	(get_svr4_info): Rewrite.
	(svr4_sspace_data_cleanup): New.
	(open_symbol_file_object): Adjust.
	(svr4_default_sos): Adjust.
	(svr4_fetch_objfile_link_map): Adjust.
	(interp_text_sect_low, interp_text_sect_high, interp_plt_sect_low)
	(interp_plt_sect_high): Delete.
	(svr4_in_dynsym_resolve_code): Adjust.
	(enable_break): Adjust.
	(svr4_clear_solib): Revert bit that removed the svr4_info here,
	and reinstate clearing debug_base, debug_loader_offset_p,
	debug_loader_offset and debug_loader_name.
	(_initialize_svr4_solib): Register solib_svr4_pspace_data.  Don't
	install an inferior_exit observer anymore.

	* printcmd.c (struct display) <pspace>: New field.
	(display_command): Set the display's sspace.
	(do_one_display): Match the display's sspace.
	(display_uses_solib_p): Ditto.

	* linux-fork.c (detach_fork): Moved to infrun.c.
	(_initialize_linux_fork): Moved "detach-on-fork" command to
	infrun.c.
	* infrun.c (detach_fork): Moved from linux-fork.c.
	(proceed_after_vfork_done): New.
	(handle_vfork_child_exec_or_exit): New.
	(follow_exec_mode_replace, follow_exec_mode_keep)
	(follow_exec_mode_names, follow_exec_mode_string)
	(show_follow_exec_mode_string): New.
	(follow_exec): New.  Reinstate the mark_breakpoints_out call.
	Remove shared libraries before attaching new executable.  If user
	wants to keep the inferior, keep it.
	(displaced_step_fixup): Adjust to pass an address space to the
	breakpoints module.
	(resume): Ditto.
	(clear_proceed_status): In all-stop mode, always clear the proceed
	status of all threads.
	(prepare_to_proceed): Adjust to pass an address space to the
	breakpoints module.
	(proceed): Ditto.
	(adjust_pc_after_break): Ditto.
	(handle_inferior_event): When handling a process exit, switch the
	program space to the inferior's that had exited.  Call
	handle_vfork_child_exec_or_exit.  Adjust to pass an address space
	to the breakpoints module.  In non-stop mode, when following a
	fork and detach-fork is off, also resume the other branch.  Handle
	TARGET_WAITKIND_VFORK_DONE.  Set the program space in sals.
	(normal_stop): Prune inferiors.
	(_initialize_infrun): Install the new "follow-exec-mode" command.
	"detach-on-fork" moved here.

	* regcache.h (get_regcache_aspace): Declare.
	* regcache.c (struct regcache) <aspace>: New field.
	(regcache_xmalloc): Clear the aspace.
	(get_regcache_aspace): New.
	(regcache_cpy): Copy the aspace field.
	(regcache_cpy_no_passthrough): Ditto.
	(get_thread_regcache): Fetch the thread's address space from the
	target, and store it in the regcache.

	* infcall.c (call_function_by_hand): Set the sal's pspace.

	* arch-utils.c (default_has_shared_address_space): New.
	* arch-utils.h (default_has_shared_address_space): Declare.

	* gdbarch.sh (has_shared_address_space): New.
	* gdbarch.h, gdbarch.c: Regenerate.

	* linux-tdep.c: Include auxv.h, target.h, elf/common.h.
	(linux_has_shared_address_space): New.
	(_initialize_linux_tdep): Declare.

	* arm-tdep.c (arm_software_single_step): Pass the frame's address
	space to insert_single_step_breakpoint.
	* arm-linux-tdep.c (arm_linux_software_single_step): Pass the
	frame's pspace to breakpoint functions.
	* cris-tdep.c (crisv32_single_step_through_delay): Ditto.
	(cris_software_single_step): Ditto.
	* mips-tdep.c (deal_with_atomic_sequence): Add frame argument.
	Pass the frame's pspace to breakpoint functions.
	(mips_software_single_step): Adjust.
	(mips_single_step_through_delay): Adjust.
	* rs6000-aix-tdep.c (rs6000_software_single_step): Adjust.
	* rs6000-tdep.c (ppc_deal_with_atomic_sequence): Adjust.
	* solib-irix.c (enable_break): Adjust to pass the current frame's
	address space to breakpoint functions.
	* sparc-tdep.c (sparc_software_single_step): Ditto.
	* spu-tdep.c (spu_software_single_step): Ditto.
	* alpha-tdep.c (alpha_software_single_step): Ditto.
	* record.c (record_wait): Adjust to pass an address space to the
	breakpoints module.

	* fork-child.c (fork_inferior): Set the new inferior's program and
	address spaces.
	* inf-ptrace.c (inf_ptrace_follow_fork): Copy the parent's program
	and address spaces.
	(inf_ptrace_attach): Set the inferior's program and address spaces.
	* linux-nat.c: Include "solib.h".
	(linux_child_follow_fork): Manage parent and child's program and
	address spaces.	 Clone the parent's program space if necessary.
	Don't wait for the vfork to be done here.  Refuse to resume if
	following the vfork parent while leaving the child stopped.
	(resume_callback): Don't resume a vfork parent.
	(linux_nat_resume): Also check for pending events in the
	lp->waitstatus field.
	(linux_handle_extended_wait): Report TARGET_WAITKIND_VFORK_DONE
	events to the core.
	(stop_wait_callback): Don't wait for SIGSTOP on vfork parents.
	(cancel_breakpoint): Adjust.
	* linux-thread-db.c (thread_db_wait): Don't remove thread event
	breakpoints here.
	(thread_db_mourn_inferior): Don't mark breakpoints out here.
	Remove thread event breakpoints after mourning.
	* corelow.c: Include progspace.h.
	(core_open): Set the inferior's program and address spaces.
	* remote.c (remote_add_inferior): Set the new inferior's program
	and address spaces.
	(remote_start_remote): Update address spaces.
	(extended_remote_create_inferior_1): Don't init the thread list if
	we already debugging other inferiors.
	* darwin-nat.c (darwin_attach): Set the new inferior's program and
	address spaces.
	* gnu-nat.c (gnu_attach): Ditto.
	* go32-nat.c (go32_create_inferior): Ditto.
	* inf-ttrace.c (inf_ttrace_follow_fork, inf_ttrace_attach): Ditto.
	* monitor.c (monitor_open): Ditto.
	* nto-procfs.c (procfs_attach, procfs_create_inferior): Ditto.
	* procfs.c (do_attach): Ditto.
	* windows-nat.c (do_initial_windows_stuff): Ditto.

	* inflow.c (inferior_process_group)
	(terminal_init_inferior_with_pgrp, terminal_inferior,
	(terminal_ours_1, inflow_inferior_exit, copy_terminal_info)
	(child_terminal_info, new_tty_postfork, set_sigint_trap): Adjust
	to use per-inferior data instead of inferior->terminal_info.
	(inflow_inferior_data): New.
	(inflow_new_inferior): Delete.
	(inflow_inferior_data_cleanup): New.
	(get_inflow_inferior_data): New.

	* mi/mi-interp.c (mi_new_inferior): Rename to...
	(mi_inferior_appeared): ... this.
	(mi_interpreter_init): Adjust.

	* tui/tui-disasm.c: Include "progspace.h".
	(tui_set_disassem_content): Pass an address space to
	breakpoint_here_p.

	* NEWS: Mention multi-program debugging support.  Mention new
	commands "add-inferior", "clone-inferior", "remove-inferior",
	"maint info program-spaces", and new option "set
	follow-exec-mode".

2009-10-19  Pedro Alves	 <pedro@codesourcery.com>
	    Stan Shebs	<stan@codesourcery.com>

	gdb/doc/
	* observer.texi (new_inferior): Rename to...
	(inferior_appeared): ... this.

2009-10-19  Pedro Alves	 <pedro@codesourcery.com>
	    Stan Shebs	<stan@codesourcery.com>

	gdb/testsuite/
	* gdb.base/foll-vfork.exp: Adjust to spell out "follow-fork".
	* gdb.base/foll-exec.exp: Adjust to expect a process id before
	"Executing new program".
	* gdb.base/foll-fork.exp: Adjust to spell out "follow-fork".
	* gdb.base/multi-forks.exp: Ditto.  Adjust to the inferior being
	left listed after having been killed.
	* gdb.base/attach.exp: Adjust to spell out "symbol-file".
	* gdb.base/maint.exp: Adjust test.

	* Makefile.in (ALL_SUBDIRS): Add gdb.multi.
	* gdb.multi/Makefile.in: New.
	* gdb.multi/base.exp: New.
	* gdb.multi/goodbye.c: New.
	* gdb.multi/hangout.c: New.
	* gdb.multi/hello.c: New.
	* gdb.multi/bkpt-multi-exec.c: New.
	* gdb.multi/bkpt-multi-exec.exp: New.
	* gdb.multi/crashme.c: New.

2009-10-19  Pedro Alves	 <pedro@codesourcery.com>
	    Stan Shebs	<stan@codesourcery.com>

	gdb/doc/
	* gdb.texinfo (Inferiors): Rename node to ...
	(Inferiors and Programs): ... this.  Mention running multiple
	programs in the same debug session.
	<info inferiors>: Mention the new 'Executable' column if "info
	inferiors".  Update examples.  Document the "add-inferior",
	"clone-inferior", "remove-inferior" and "maint info
	program-spaces" commands.
	(Process): Rename node to...
	(Forks): ... this.  Document "set|show follow-exec-mode".

1 files changed, 283 insertions, 0 deletions

diff --git a/gdb/progspace.h b/gdb/progspace.h
new file mode 100644
index 00000000000..2a0d1d294c5
--- /dev/null
+++ b/gdb/progspace.h
@@ -0,0 +1,283 @@
+/* Program and address space management, for GDB, the GNU debugger.
+
+   Copyright (C) 2009 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+
+#ifndef PROGSPACE_H
+#define PROGSPACE_H
+
+#include "target.h"
+#include "vec.h"
+
+struct target_ops;
+struct bfd;
+struct objfile;
+struct inferior;
+struct exec;
+struct address_space;
+struct program_space_data;
+
+/* A program space represents a symbolic view of an address space.
+   Roughly speaking, it holds all the data associated with a
+   non-running-yet program (main executable, main symbols), and when
+   an inferior is running and is bound to it, includes the list of its
+   mapped in shared libraries.
+
+   In the traditional debugging scenario, there's a 1-1 correspondence
+   among program spaces, inferiors and address spaces, like so:
+
+     pspace1 (prog1) <--> inf1(pid1) <--> aspace1
+
+   In the case of debugging more than one traditional unix process or
+   program, we still have:
+
+     |-----------------+------------+---------|
+     | pspace1 (prog1) | inf1(pid1) | aspace1 |
+     |----------------------------------------|
+     | pspace2 (prog1) | no inf yet | aspace2 |
+     |-----------------+------------+---------|
+     | pspace3 (prog2) | inf2(pid2) | aspace3 |
+     |-----------------+------------+---------|
+
+   In the former example, if inf1 forks (and GDB stays attached to
+   both processes), the new child will have its own program and
+   address spaces.  Like so:
+
+     |-----------------+------------+---------|
+     | pspace1 (prog1) | inf1(pid1) | aspace1 |
+     |-----------------+------------+---------|
+     | pspace2 (prog1) | inf2(pid2) | aspace2 |
+     |-----------------+------------+---------|
+
+   However, had inf1 from the latter case vforked instead, it would
+   share the program and address spaces with its parent, until it
+   execs or exits, like so:
+
+     |-----------------+------------+---------|
+     | pspace1 (prog1) | inf1(pid1) | aspace1 |
+     |                 | inf2(pid2) |         |
+     |-----------------+------------+---------|
+
+   When the vfork child execs, it is finally given new program and
+   address spaces.
+
+     |-----------------+------------+---------|
+     | pspace1 (prog1) | inf1(pid1) | aspace1 |
+     |-----------------+------------+---------|
+     | pspace2 (prog1) | inf2(pid2) | aspace2 |
+     |-----------------+------------+---------|
+
+   There are targets where the OS (if any) doesn't provide memory
+   management or VM protection, where all inferiors share the same
+   address space --- e.g. uClinux.  GDB models this by having all
+   inferiors share the same address space, but, giving each its own
+   program space, like so:
+
+     |-----------------+------------+---------|
+     | pspace1 (prog1) | inf1(pid1) |         |
+     |-----------------+------------+         |
+     | pspace2 (prog1) | inf2(pid2) | aspace1 |
+     |-----------------+------------+         |
+     | pspace3 (prog2) | inf3(pid3) |         |
+     |-----------------+------------+---------|
+
+   The address space sharing matters for run control and breakpoints
+   management.  E.g., did we just hit a known breakpoint that we need
+   to step over?  Is this breakpoint a duplicate of this other one, or
+   do I need to insert a trap?
+
+   Then, there are targets where all symbols look the same for all
+   inferiors, although each has its own address space, as e.g.,
+   Ericsson DICOS.  In such case, the model is:
+
+     |---------+------------+---------|
+     |         | inf1(pid1) | aspace1 |
+     |         +------------+---------|
+     | pspace  | inf2(pid2) | aspace2 |
+     |         +------------+---------|
+     |         | inf3(pid3) | aspace3 |
+     |---------+------------+---------|
+
+   Note however, that the DICOS debug API takes care of making GDB
+   believe that breakpoints are "global".  That is, although each
+   process does have its own private copy of data symbols (just like a
+   bunch of forks), to the breakpoints module, all processes share a
+   single address space, so all breakpoints set at the same address
+   are duplicates of each other, even breakpoints set in the data
+   space (e.g., call dummy breakpoints placed on stack).  This allows
+   a simplification in the spaces implementation: we avoid caring for
+   a many-many links between address and program spaces.  Either
+   there's a single address space bound to the program space
+   (traditional unix/uClinux), or, in the DICOS case, the address
+   space bound to the program space is mostly ignored.  */
+
+/* The program space structure.  */
+
+struct program_space
+  {
+    /* Pointer to next in linked list.  */
+    struct program_space *next;
+
+    /* Unique ID number.  */
+    int num;
+
+    /* The main executable loaded into this program space.  This is
+       managed by the exec target.  */
+
+    /* The BFD handle for the main executable.  */
+    bfd *ebfd;
+    /* The last-modified time, from when the exec was brought in.  */
+    long ebfd_mtime;
+
+    /* The address space attached to this program space.  More than one
+       program space may be bound to the same address space.  In the
+       traditional unix-like debugging scenario, this will usually
+       match the address space bound to the inferior, and is mostly
+       used by the breakpoints module for address matches.  If the
+       target shares a program space for all inferiors and breakpoints
+       are global, then this field is ignored (we don't currently
+       support inferiors sharing a program space if the target doesn't
+       make breakpoints global).  */
+    struct address_space *aspace;
+
+    /* True if this program space's section offsets don't yet represent
+       the final offsets of the "live" address space (that is, the
+       section addresses still require the relocation offsets to be
+       applied, and hence we can't trust the section addresses for
+       anything that pokes at live memory).  E.g., for qOffsets
+       targets, or for PIE executables, until we connect and ask the
+       target for the final relocation offsets, the symbols we've used
+       to set breakpoints point at the wrong addresses.  */
+    int executing_startup;
+
+    /* The object file that the main symbol table was loaded from
+       (e.g. the argument to the "symbol-file" or "file" command).  */
+    struct objfile *symfile_object_file;
+
+    /* All known objfiles are kept in a linked list.  This points to
+       the head of this list. */
+    struct objfile *objfiles;
+
+    /* The set of target sections matching the sections mapped into
+       this program space.  Managed by both exec_ops and solib.c.  */
+    struct target_section_table target_sections;
+
+    /* List of shared objects mapped into this space.  Managed by
+       solib.c.  */
+    struct so_list *so_list;
+
+    /* Per pspace data-pointers required by other GDB modules.  */
+    void **data;
+    unsigned num_data;
+  };
+
+/* The object file that the main symbol table was loaded from (e.g. the
+   argument to the "symbol-file" or "file" command).  */
+
+#define symfile_objfile current_program_space->symfile_object_file
+
+/* All known objfiles are kept in a linked list.  This points to the
+   root of this list. */
+#define object_files current_program_space->objfiles
+
+/* The set of target sections matching the sections mapped into the
+   current program space.  */
+#define current_target_sections (&current_program_space->target_sections)
+
+/* The list of all program spaces.  There's always at least one.  */
+extern struct program_space *program_spaces;
+
+/* The current program space.  This is always non-null.  */
+extern struct program_space *current_program_space;
+
+#define ALL_PSPACES(pspace) \
+  for ((pspace) = program_spaces; (pspace) != NULL; (pspace) = (pspace)->next)
+
+/* Add a new empty program space, and assign ASPACE to it.  Returns the
+   pointer to the new object.  */
+extern struct program_space *add_program_space (struct address_space *aspace);
+
+/* Release PSPACE and removes it from the pspace list.  */
+extern void remove_program_space (struct program_space *pspace);
+
+/* Returns the number of program spaces listed.  */
+extern int number_of_program_spaces (void);
+
+/* Copies program space SRC to DEST.  Copies the main executable file,
+   and the main symbol file.  Returns DEST.  */
+extern struct program_space *clone_program_space (struct program_space *dest,
+						struct program_space *src);
+
+/* Save the current program space so that it may be restored by a later
+   call to do_cleanups.  Returns the struct cleanup pointer needed for
+   later doing the cleanup.  */
+extern struct cleanup *save_current_program_space (void);
+
+/* Sets PSPACE as the current program space.  This is usually used
+   instead of set_current_space_and_thread when the current
+   thread/inferior is not important for the operations that follow.
+   E.g., when accessing the raw symbol tables.  If memory access is
+   required, then you should use switch_to_program_space_and_thread.
+   Otherwise, it is the caller's responsibility to make sure that the
+   currently selected inferior/thread matches the selected program
+   space.  */
+extern void set_current_program_space (struct program_space *pspace);
+
+/* Saves the current thread (may be null), frame and program space in
+   the current cleanup chain.  */
+extern struct cleanup *save_current_space_and_thread (void);
+
+/* Switches full context to program space PSPACE.  Switches to the
+   first thread found bound to PSPACE.  */
+extern void switch_to_program_space_and_thread (struct program_space *pspace);
+
+/* Create a new address space object, and add it to the list.  */
+extern struct address_space *new_address_space (void);
+
+/* Maybe create a new address space object, and add it to the list, or
+   return a pointer to an existing address space, in case inferiors
+   share an address space.  */
+extern struct address_space *maybe_new_address_space (void);
+
+/* Update all program spaces matching to address spaces.  The user may
+   have created several program spaces, and loaded executables into
+   them before connecting to the target interface that will create the
+   inferiors.  All that happens before GDB has a chance to know if the
+   inferiors will share an address space or not.  Call this after
+   having connected to the target interface and having fetched the
+   target description, to fixup the program/address spaces
+   mappings.  */
+extern void update_address_spaces (void);
+
+/* Prune away automatically added program spaces that aren't required
+   anymore.  */
+extern void prune_program_spaces (void);
+
+/* Keep a registry of per-pspace data-pointers required by other GDB
+   modules.  */
+
+extern const struct program_space_data *register_program_space_data (void);
+extern const struct program_space_data *register_program_space_data_with_cleanup
+  (void (*cleanup) (struct program_space *, void *));
+extern void clear_program_space_data (struct program_space *pspace);
+extern void set_program_space_data (struct program_space *pspace,
+			      const struct program_space_data *data, void *value);
+extern void *program_space_data (struct program_space *pspace,
+			   const struct program_space_data *data);
+
+#endif