Allow enabling/disabling breakpoint location ranges

When a breakpoint has multiple locations, like e.g.:

 Num  Type       Disp Enb  Address    What
 1    breakpoint keep y    <MULTIPLE>
 1.1                  y    0x080486a2 in void foo<int>()...
 1.2                  y    0x080486ca in void foo<double>()...
 [....]
 1.5                  y    0x080487fa in void foo<long>()...

it's possible to enable/disable the individual locations using the
'<breakpoint_number>.<location_number>' syntax, like e.g.:

 (gdb) disable 1.2 1.3 1.4 1.5

That's inconvenient when you have a long list of locations to disable,
however.

This patch adds shorthand for the above, by making it possible to
specify a range of locations with the following syntax (similar to
thread id ranges):

 <breakpoint_number>.<first_location_number>-<last_location_number>

For example, the command above can now be simplified to:

 (gdb) disable 1.2-5

gdb/ChangeLog:
2017-11-07  Xavier Roirand  <roirand@adacore.com>
	    Pedro Alves  <palves@redhat.com>

	* breakpoint.c (map_breakpoint_number_range): New, factored out
	from ...
	(map_breakpoint_numbers): ... here.
	(find_location_by_number): Change parameters from string to
	breakpoint number and location.
	(extract_bp_number_and_location): New function.
	(enable_disable_bp_num_loc)
	(enable_disable_breakpoint_location_range)
	(enable_disable_command): New functions, factored out ...
	(enable_command, disable_command): ... these functions, and
	adjusted to support ranges.
	* NEWS: Document enable/disable breakpoint location range feature.

gdb/doc/ChangeLog:
2017-11-07  Xavier Roirand  <roirand@adacore.com>
	    Pedro Alves  <palves@redhat.com>

	* gdb.texinfo (Set Breaks): Document support for breakpoint
	location ranges in the enable/disable commands.

gdb/testsuite/ChangeLog:
2017-11-07  Xavier Roirand  <roirand@adacore.com>
	    Pedro Alves  <palves@redhat.com>

	* gdb.base/ena-dis-br.exp: Add reference to
	gdb.cp/ena-dis-br-range.exp.
	* gdb.cp/ena-dis-br-range.exp: New file.
	* gdb.cp/ena-dis-br-range.cc: New file.

2 files changed, 16 insertions, 8 deletions

diff --git a/gdb/doc/ChangeLog b/gdb/doc/ChangeLog
index e3ea4ec..98eab72 100644
--- a/gdb/doc/ChangeLog
+++ b/gdb/doc/ChangeLog
@@ -1,3 +1,9 @@
+2017-11-07  Xavier Roirand  <roirand@adacore.com>
+	    Pedro Alves  <palves@redhat.com>
+
+	* gdb.texinfo (Set Breaks): Document support for breakpoint
+	location ranges in the enable/disable commands.
+
 2017-10-04  Sergio Durigan Junior  <sergiodj@redhat.com>
 
 	* gdb.texinfo (Starting your Program) <The working directory.>:
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index bfeb7a9..29d4789 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -3927,15 +3927,17 @@ Num     Type           Disp Enb  Address    What
 1.2                         y    0x080486ca in void foo<double>() at t.cc:8
 @end smallexample
 
-Each location can be individually enabled or disabled by passing
+You cannot delete the individual locations from a breakpoint.  However,
+each location can be individually enabled or disabled by passing
 @var{breakpoint-number}.@var{location-number} as argument to the
-@code{enable} and @code{disable} commands.  Note that you cannot
-delete the individual locations from the list, you can only delete the
-entire list of locations that belong to their parent breakpoint (with
-the @kbd{delete @var{num}} command, where @var{num} is the number of
-the parent breakpoint, 1 in the above example).  Disabling or enabling
-the parent breakpoint (@pxref{Disabling}) affects all of the locations
-that belong to that breakpoint.
+@code{enable} and @code{disable} commands.  It's also possible to
+@code{enable} and @code{disable} a range of @var{location-number}
+locations using a @var{breakpoint-number} and two @var{location-number}s,
+in increasing order, separated by a hyphen, like
+@kbd{@var{breakpoint-number}.@var{location-number1}-@var{location-number2}},
+in which case @value{GDBN} acts on all the locations in the range (inclusive).
+Disabling or enabling the parent breakpoint (@pxref{Disabling}) affects
+all of the locations that belong to that breakpoint.
 
 @cindex pending breakpoints
 It's quite common to have a breakpoint inside a shared library.