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[patch v4 1/3] Create remove-symbol-file command.


Create remove-symbol-file command for removing
symbol files added via the add-symbol-file command.

2013-18-03  Nicolas Blanc  <nicolas.blanc@intel.com>

	* breakpoint.c (is_addr_in_objfile): Create static helper function.
	(disable_breakpoints_in_freed_objfile): Create function for disabling
	breakpoints in objfiles upon free_objfile notifications.
	* objfiles.c (free_objfile): Notify free_objfile.
	* objfiles.h (struct objfile): Add comment for low_addr.
	* printcmd.c (clear_dangling_display_expressions): Act upon free_objfile
	events instead of solib_unloaded events.
	(_initialize_printcmd): Register observer for free_objfile instead
	of solib_unloaded notifications.
	* solib.c (remove_user_added_objfile): Create function for removing
	dangling references upon notification of free_objfile.
	* symfile.c (add_symbol_file_command): Set OBJFILE->LOW_ADDR.
	(remove_symbol_file_command): Create command for removing symbol files.
	(_initialize_symfile): Add remove-symbol-file.
gdb/doc
	* observer.texi: Created free_objfile event.

Signed-off-by: Nicolas Blanc <nicolas.blanc@intel.com>
---
 gdb/breakpoint.c      |   82 +++++++++++++++++++++++++++++++++++++++++++++++--
 gdb/doc/observer.texi |    4 ++
 gdb/objfiles.c        |    3 ++
 gdb/objfiles.h        |    4 ++
 gdb/printcmd.c        |   15 +++++---
 gdb/solib.c           |   23 ++++++++++++++
 gdb/symfile.c         |   55 ++++++++++++++++++++++++++++++++-
 7 files changed, 176 insertions(+), 10 deletions(-)

diff --git a/gdb/breakpoint.c b/gdb/breakpoint.c
index b4d2f27..e42b32d 100644
--- a/gdb/breakpoint.c
+++ b/gdb/breakpoint.c
@@ -7417,9 +7417,9 @@ disable_breakpoints_in_shlibs (void)
   }
 }
 
-/* Disable any breakpoints and tracepoints that are in an unloaded shared
-   library.  Only apply to enabled breakpoints, disabled ones can just stay
-   disabled.  */
+/* Disable any breakpoints and tracepoints that are in SOLIB upon
+   notification of unloaded_shlib.  Only apply to enabled breakpoints,
+   disabled ones can just stay disabled.  */
 
 static void
 disable_breakpoints_in_unloaded_shlib (struct so_list *solib)
@@ -7471,6 +7471,81 @@ disable_breakpoints_in_unloaded_shlib (struct so_list *solib)
   }
 }
 
+/* Return 1 if ADDR maps in one of the sections of OBJFILE and 0
+   otherwise.  OBJFILE must be valid.  */
+
+static inline int
+is_addr_in_objfile (CORE_ADDR addr, const struct objfile * objfile)
+{
+  struct obj_section *osect;
+  ALL_OBJFILE_OSECTIONS (objfile, osect)
+  {
+    if (obj_section_addr (osect) <= addr
+	&& addr < obj_section_endaddr (osect))
+      return 1;
+  }
+  return 0;
+}
+
+/* Disable any breakpoints and tracepoints in OBJFILE upon
+   notification of free_objfile.  Only apply to enabled breakpoints,
+   disabled ones can just stay disabled.  */
+
+static void
+disable_breakpoints_in_freed_objfile (struct objfile * objfile)
+{
+  struct breakpoint *b;
+
+  if (objfile == NULL)
+    return;
+
+  /* If the file is a shared library not loaded by the user then
+     solib_unloaded was notified and disable_breakpoints_in_unloaded_shlib
+     was called.  In that case there is no need to take action again.  */
+  if ((objfile->flags & OBJF_SHARED) && !(objfile->flags & OBJF_USERLOADED))
+    return;
+
+  ALL_BREAKPOINTS (b)
+  {
+    struct bp_location *loc;
+    int bp_modified = 0;
+    int is_no_tracepoint = !is_tracepoint (b);
+
+    if (is_no_tracepoint
+	&& b->type != bp_breakpoint
+	&& b->type != bp_jit_event
+	&& b->type != bp_hardware_breakpoint)
+      continue;
+
+    for (loc = b->loc; loc != NULL; loc = loc->next)
+      {
+	CORE_ADDR loc_addr = loc->address;
+
+	if (is_no_tracepoint
+	    && loc->loc_type != bp_loc_hardware_breakpoint
+	    && loc->loc_type != bp_loc_software_breakpoint)
+	  continue;
+
+	if (loc->shlib_disabled != 0)
+	  continue;
+
+	if (objfile->pspace != loc->pspace)
+	  continue;
+
+	if (is_addr_in_objfile (loc_addr, objfile))
+	  {
+	    loc->shlib_disabled = 1;
+	    loc->inserted = 0;
+	    bp_modified = 1;
+	  }
+      }
+
+    if (bp_modified)
+      observer_notify_breakpoint_modified (b);
+  }
+
+}
+
 /* FORK & VFORK catchpoints.  */
 
 /* An instance of this type is used to represent a fork or vfork
@@ -15875,6 +15950,7 @@ _initialize_breakpoint (void)
   initialize_breakpoint_ops ();
 
   observer_attach_solib_unloaded (disable_breakpoints_in_unloaded_shlib);
+  observer_attach_free_objfile (disable_breakpoints_in_freed_objfile);
   observer_attach_inferior_exit (clear_syscall_counts);
   observer_attach_memory_changed (invalidate_bp_value_on_memory_change);
 
diff --git a/gdb/doc/observer.texi b/gdb/doc/observer.texi
index adb7085..f753965 100644
--- a/gdb/doc/observer.texi
+++ b/gdb/doc/observer.texi
@@ -138,6 +138,10 @@ Called with @var{objfile} equal to @code{NULL} to indicate
 previously loaded symbol table data has now been invalidated.
 @end deftypefun
 
+@deftypefun void free_objfile (struct objfile *@var{objfile})
+The object file specified by @var{objfile} is about to be freed.
+@end deftypefun
+
 @deftypefun void new_thread (struct thread_info *@var{t})
 The thread specified by @var{t} has been created.
 @end deftypefun
diff --git a/gdb/objfiles.c b/gdb/objfiles.c
index 3e49ea2..c70a5a2 100644
--- a/gdb/objfiles.c
+++ b/gdb/objfiles.c
@@ -530,6 +530,9 @@ free_objfile_separate_debug (struct objfile *objfile)
 void
 free_objfile (struct objfile *objfile)
 {
+  /* First notify observers that this objfile is about to be freed.  */
+  observer_notify_free_objfile (objfile);
+
   /* Free all separate debug objfiles.  */
   free_objfile_separate_debug (objfile);
 
diff --git a/gdb/objfiles.h b/gdb/objfiles.h
index 93149e2..644e780 100644
--- a/gdb/objfiles.h
+++ b/gdb/objfiles.h
@@ -204,6 +204,10 @@ struct objfile
 
     char *name;
 
+    /* The base address of the object file, which is often assumed to be
+       the address of the text section.  The remove-symbol-file command
+       uses this field to identify the object file to remove.  */
+
     CORE_ADDR addr_low;
 
     /* Some flag bits for this objfile.
diff --git a/gdb/printcmd.c b/gdb/printcmd.c
index 2cc33d0..bd4bd42 100644
--- a/gdb/printcmd.c
+++ b/gdb/printcmd.c
@@ -1928,21 +1928,24 @@ disable_display_command (char *args, int from_tty)
    an item by re-parsing .exp_string field in the new execution context.  */
 
 static void
-clear_dangling_display_expressions (struct so_list *solib)
+clear_dangling_display_expressions (struct objfile *objfile)
 {
-  struct objfile *objfile = solib->objfile;
   struct display *d;
+  struct program_space *pspace;
 
   /* With no symbol file we cannot have a block or expression from it.  */
   if (objfile == NULL)
     return;
+  pspace = objfile->pspace;
   if (objfile->separate_debug_objfile_backlink)
-    objfile = objfile->separate_debug_objfile_backlink;
-  gdb_assert (objfile->pspace == solib->pspace);
+    {
+      objfile = objfile->separate_debug_objfile_backlink;
+      gdb_assert (objfile->pspace == pspace);
+    }
 
   for (d = display_chain; d != NULL; d = d->next)
     {
-      if (d->pspace != solib->pspace)
+      if (d->pspace != pspace)
 	continue;
 
       if (lookup_objfile_from_block (d->block) == objfile
@@ -2474,7 +2477,7 @@ _initialize_printcmd (void)
 
   current_display_number = -1;
 
-  observer_attach_solib_unloaded (clear_dangling_display_expressions);
+  observer_attach_free_objfile (clear_dangling_display_expressions);
 
   add_info ("address", address_info,
 	    _("Describe where symbol SYM is stored."));
diff --git a/gdb/solib.c b/gdb/solib.c
index a3479c5..a897777 100644
--- a/gdb/solib.c
+++ b/gdb/solib.c
@@ -1446,6 +1446,27 @@ gdb_bfd_lookup_symbol (bfd *abfd,
   return symaddr;
 }
 
+/* SO_LIST_HEAD may contain user-loaded object files that can be removed
+   out-of-band by the user.  So upon notification of free_objfile remove
+   any reference to any user-loaded file that is about to be freed.  */
+
+static void
+remove_user_added_objfile (struct objfile *objfile)
+{
+  struct so_list *so;
+
+  if (!objfile)
+    return;
+
+  if (objfile->flags & OBJF_USERLOADED)
+    {
+      for (so = so_list_head; so != NULL; so = so->next)
+	if (so->objfile == objfile)
+	  so->objfile = NULL;
+    }
+}
+
+
 extern initialize_file_ftype _initialize_solib; /* -Wmissing-prototypes */
 
 void
@@ -1453,6 +1474,8 @@ _initialize_solib (void)
 {
   solib_data = gdbarch_data_register_pre_init (solib_init);
 
+  observer_attach_free_objfile (remove_user_added_objfile);
+
   add_com ("sharedlibrary", class_files, sharedlibrary_command,
 	   _("Load shared object library symbols for files matching REGEXP."));
   add_info ("sharedlibrary", info_sharedlibrary_command,
diff --git a/gdb/symfile.c b/gdb/symfile.c
index e9609b2..7c5989c 100644
--- a/gdb/symfile.c
+++ b/gdb/symfile.c
@@ -2175,6 +2175,8 @@ add_symbol_file_command (char *args, int from_tty)
   int expecting_sec_name = 0;
   int expecting_sec_addr = 0;
   char **argv;
+  struct objfile *objf;
+  CORE_ADDR addr_low;
 
   struct sect_opt
   {
@@ -2307,12 +2309,17 @@ add_symbol_file_command (char *args, int from_tty)
     }
   section_addrs->num_sections = sec_num;
 
+  addr_low = section_addrs->other[0].addr;
+
   if (from_tty && (!query ("%s", "")))
     error (_("Not confirmed."));
 
-  symbol_file_add (filename, from_tty ? SYMFILE_VERBOSE : 0,
+  objf = symbol_file_add (filename, from_tty ? SYMFILE_VERBOSE : 0,
                    section_addrs, flags);
 
+  /* Set the low address of the object for identification.  */
+  objf->addr_low = addr_low;
+
   /* Getting new symbols may change our opinion about what is
      frameless.  */
   reinit_frame_cache ();
@@ -2320,6 +2327,46 @@ add_symbol_file_command (char *args, int from_tty)
 }
 
 
+
+/* This function removes a symbol file that was added via add-symbol-file.  */
+
+static void
+remove_symbol_file_command (char *args, int from_tty)
+{
+  CORE_ADDR addr = 0;
+  struct objfile* objf;
+  struct gdbarch *gdbarch = get_current_arch ();
+
+  dont_repeat ();
+
+  if (args == NULL)
+    error (_("USAGE: remove-symbol-file <text_address>"));
+
+  addr = parse_and_eval_address (args);
+
+  ALL_OBJFILES (objf)
+  {
+    if (objf->flags & OBJF_USERLOADED && objf->addr_low == addr)
+      break;
+  }
+
+  if (objf == NULL)
+    error (_("no user-added symbol file for .text_addr = 0x%s"),
+	   phex_nz (addr, sizeof (addr)));
+
+  printf_unfiltered (_("Remove symbol table from file \"%s\"\
+ at .text_addr = %s\n"),
+		     objf->name, paddress (gdbarch, addr));
+
+  if (from_tty && (!query ("%s", "")))
+    error (_("Not confirmed."));
+
+  free_objfile (objf);
+  clear_symtab_users (0);
+
+}
+
+
 typedef struct objfile *objfilep;
 
 DEF_VEC_P (objfilep);
@@ -3734,6 +3781,12 @@ with the text.  SECT is a section name to be loaded at SECT_ADDR."),
 	       &cmdlist);
   set_cmd_completer (c, filename_completer);
 
+  c = add_cmd ("remove-symbol-file", class_files,
+	       remove_symbol_file_command, _("\
+Remove a symbol file loaded via the add-symbol-file command.\n\
+Usage: remove-symbol-file ADDR.\nADDR is the starting address of the\
+ text section of the file to remove."), &cmdlist);
+
   c = add_cmd ("load", class_files, load_command, _("\
 Dynamically load FILE into the running program, and record its symbols\n\
 for access from GDB.\n\
-- 
1.7.6.5


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