text: /* Program and address space management, for GDB, the GNU debugger.
  
     Copyright (C) 2009-2016 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"
  #include "gdb_vecs.h"
  #include "registry.h"
  
  struct target_ops;
  struct bfd;
  struct objfile;
  struct inferior;
  struct exec;
  struct address_space;
  struct program_space_data;
  struct address_space_data;
  
  typedef struct so_list *so_list_ptr;
  DEF_VEC_P (so_list_ptr);
  
  /* 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;
      /* Similar to bfd_get_filename (exec_bfd) but in original form given
         by user, without symbolic links and pathname resolved.
         It needs to be freed by xfree.  It is not NULL iff EBFD is not NULL.  */
      char *pspace_exec_filename;
  
      /* 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;
  
      /* True if no breakpoints should be inserted in this program
         space.  */
      int breakpoints_not_allowed;
  
      /* 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;
  
      /* Number of calls to solib_add.  */
      unsigned solib_add_generation;
  
      /* When an solib is added, it is also added to this vector.  This
         is so we can properly report solib changes to the user.  */
      VEC (so_list_ptr) *added_solibs;
  
      /* When an solib is removed, its name is added to this vector.
         This is so we can properly report solib changes to the user.  */
      VEC (char_ptr) *deleted_solibs;
  
      /* Per pspace data-pointers required by other GDB modules.  */
      REGISTRY_FIELDS;
    };
  
  /* 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);
  
  /* 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);
  
  /* Returns true iff there's no inferior bound to PSPACE.  */
  extern int program_space_empty_p (struct program_space *pspace);
  
  /* 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, giving preference to the
     current thread, if there's one and it isn't executing.  */
  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);
  
  /* Returns the integer address space id of ASPACE.  */
  extern int address_space_num (struct address_space *aspace);
  
  /* 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);
  
  /* Reset saved solib data at the start of an solib event.  This lets
     us properly collect the data when calling solib_add, so it can then
     later be printed.  */
  extern void clear_program_space_solib_cache (struct program_space *);
  
  /* Keep a registry of per-pspace data-pointers required by other GDB
     modules.  */
  
  DECLARE_REGISTRY (program_space);
  
  /* Keep a registry of per-aspace data-pointers required by other GDB
     modules.  */
  
  DECLARE_REGISTRY (address_space);
  
  #endif
  