gdb/mi: New commands to catch C++ exceptions

Adds some MI commands to catch C++ exceptions.  The new commands are
-catch-throw, -catch-rethrow, and -catch-catch, these all correspond
to the CLI commands 'catch throw', 'catch rethrow', and 'catch catch'.

Each MI command takes two optional arguments, '-t' has the effect of
calling 'tcatch' instead of 'catch', for example:

   (gdb)
   -catch-throw -t

Is the same as:

   (gdb) tcatch throw

There is also a '-r REGEXP' argument that can supply a regexp to match
against the exception type, so:

   (gdb)
   -catch-catch -r PATTERN

Is the same as:

   (gdb) catch catch PATTERN

The change in print_mention_exception_catchpoint might seem a little
strange; changing the output from using ui_out::field_int and
ui_out::text to using  ui_out::message.

The print_mention_exception_catchpoint is used as the 'print_mention'
method for the exception catchpoint breakpoint object.  Most of the
other 'print_mention' methods (see breakpoint.c) use either
printf_filtered, of ui_out::message.  Using field_int was causing an
unexpected field to be added to the MI output.  Here's the output
without the change in print_mention_exception_catchpoint:

    (gdb)
    -catch-throw
    ^done,bkptno="1",bkpt={number="1",type="breakpoint",disp="keep",
                           enabled="y",addr="0x00000000004006c0",
                           what="exception throw",catch-type="throw",
                           thread-groups=["i1"],times="0"}

Notice the breakpoint number appears in both the 'bkptno' field, and
the 'number' field within the 'bkpt' tuple.  Here's the output with
the change in print_mention_exception_catchpoint:

    (gdb)
    -catch-throw
    ^done,bkpt={number="1",type="breakpoint",disp="keep",
                enabled="y",addr="0x00000000004006c0",
                what="exception throw",catch-type="throw",
                thread-groups=["i1"],times="0"}

gdb/ChangeLog:

	* NEWS: Mention new MI commands.
	* break-catch-throw.c (enum exception_event_kind): Move to
	breakpoint.h.
	(print_mention_exception_catchpoint): Output text as a single
	message.
	(catch_exception_command_1): Rename to...
	(catch_exception_event): ...this, make non-static, update header
	command, and change some parameter types.
	(catch_catch_command): Update for changes to
	catch_exception_command_1.
	(catch_throw_command): Likewise.
	(catch_rethrow_command): Likewise.
	* breakpoint.c (enum exception_event_kind): Delete.
	* breakpoint.h (enum exception_event_kind): Moved here from
	break-catch-throw.c.
	(catch_exception_event): Declare.
	* mi/mi-cmd-catch.c (mi_cmd_catch_exception_event): New function.
	(mi_cmd_catch_throw): New function.
	(mi_cmd_catch_rethrow): New function.
	(mi_cmd_catch_catch): New function.
	* mi/mi-cmds.c (mi_cmds): Add 'catch-throw', 'catch-rethrow', and
	'catch-catch' entries.
	* mi/mi-cmds.h (mi_cmd_catch_throw): Declare.
	(mi_cmd_catch_rethrow): Declare.
	(mi_cmd_catch_catch): Declare.

gdb/doc/ChangeLog:

	* gdb.texinfo (GDB/MI Catchpoint Commands): Add menu entry to new
	node.
	(C++ Exception GDB/MI Catchpoint Commands): New node to describe
	new MI commands.

gdb/testsuite/ChangeLog:

	* gdb.mi/mi-catch-cpp-exceptions.cc: New file.
	* gdb.mi/mi-catch-cpp-exceptions.exp: New file.
	* lib/mi-support.exp (mi_expect_stop): Handle 'exception-caught'
	as a stop reason.

2 files changed, 147 insertions, 0 deletions

diff --git a/gdb/doc/ChangeLog b/gdb/doc/ChangeLog
index 17048c8..f3142fd 100644
--- a/gdb/doc/ChangeLog
+++ b/gdb/doc/ChangeLog
@@ -1,3 +1,10 @@
+2019-06-15  Andrew Burgess  <andrew.burgess@embecosm.com>
+
+	* gdb.texinfo (GDB/MI Catchpoint Commands): Add menu entry to new
+	node.
+	(C++ Exception GDB/MI Catchpoint Commands): New node to describe
+	new MI commands.
+
 2019-06-13  Pedro Alves  <palves@redhat.com>
 
 	* gdb.texinfo (Command Completion): Mention command options too.
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index a5026df..9a0320e 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -29793,6 +29793,7 @@ catchpoints.
 @menu
 * Shared Library GDB/MI Catchpoint Commands::
 * Ada Exception GDB/MI Catchpoint Commands::
+* C++ Exception GDB/MI Catchpoint Commands::
 @end menu
 
 @node Shared Library GDB/MI Catchpoint Commands
@@ -29992,6 +29993,145 @@ times="0",original-location="__gnat_begin_handler"@}
 (gdb)
 @end smallexample
 
+@node C++ Exception GDB/MI Catchpoint Commands
+@subsection C@t{++} Exception @sc{gdb/mi} Catchpoints
+
+The following @sc{gdb/mi} commands can be used to create catchpoints
+that stop the execution when C@t{++} exceptions are being throw, rethrown,
+or caught.
+
+@subheading The @code{-catch-throw} Command
+@findex -catch-throw
+
+@subsubheading Synopsis
+
+@smallexample
+ -catch-throw [ -t ] [ -r @var{regexp}]
+@end smallexample
+
+Stop when the debuggee throws a C@t{++} exception.  If @var{regexp} is
+given, then only exceptions whose type matches the regular expression
+will be caught.
+
+If @samp{-t} is given, then the catchpoint is enabled only for one
+stop, the catchpoint is automatically deleted after stopping once for
+the event.
+
+@subsubheading @value{GDBN} Command
+
+The corresponding @value{GDBN} commands are @samp{catch throw}
+and @samp{tcatch throw} (@pxref{Set Catchpoints}).
+
+@subsubheading Example
+
+@smallexample
+-catch-throw -r exception_type
+^done,bkpt=@{number="1",type="breakpoint",disp="keep",enabled="y",
+  addr="0x00000000004006c0",what="exception throw",
+  catch-type="throw",thread-groups=["i1"],
+  regexp="exception_type",times="0"@}
+(gdb)
+-exec-run
+^running
+(gdb)
+~"\n"
+~"Catchpoint 1 (exception thrown), 0x00007ffff7ae00ed
+  in __cxa_throw () from /lib64/libstdc++.so.6\n"
+*stopped,bkptno="1",reason="breakpoint-hit",disp="keep",
+  frame=@{addr="0x00007ffff7ae00ed",func="__cxa_throw",
+  args=[],from="/lib64/libstdc++.so.6",arch="i386:x86-64"@},
+  thread-id="1",stopped-threads="all",core="6"
+(gdb)
+@end smallexample
+
+@subheading The @code{-catch-rethrow} Command
+@findex -catch-rethrow
+
+@subsubheading Synopsis
+
+@smallexample
+ -catch-rethrow [ -t ] [ -r @var{regexp}]
+@end smallexample
+
+Stop when a C@t{++} exception is re-thrown.  If @var{regexp} is given,
+then only exceptions whose type matches the regular expression will be
+caught.
+
+If @samp{-t} is given, then the catchpoint is enabled only for one
+stop, the catchpoint is automatically deleted after the first event is
+caught.
+
+@subsubheading @value{GDBN} Command
+
+The corresponding @value{GDBN} commands are @samp{catch rethrow}
+and @samp{tcatch rethrow} (@pxref{Set Catchpoints}).
+
+@subsubheading Example
+
+@smallexample
+-catch-rethrow -r exception_type
+^done,bkpt=@{number="1",type="breakpoint",disp="keep",enabled="y",
+  addr="0x00000000004006c0",what="exception rethrow",
+  catch-type="rethrow",thread-groups=["i1"],
+  regexp="exception_type",times="0"@}
+(gdb)
+-exec-run
+^running
+(gdb)
+~"\n"
+~"Catchpoint 1 (exception rethrown), 0x00007ffff7ae00ed
+  in __cxa_rethrow () from /lib64/libstdc++.so.6\n"
+*stopped,bkptno="1",reason="breakpoint-hit",disp="keep",
+  frame=@{addr="0x00007ffff7ae00ed",func="__cxa_rethrow",
+  args=[],from="/lib64/libstdc++.so.6",arch="i386:x86-64"@},
+  thread-id="1",stopped-threads="all",core="6"
+(gdb)
+@end smallexample
+
+@subheading The @code{-catch-catch} Command
+@findex -catch-catch
+
+@subsubheading Synopsis
+
+@smallexample
+ -catch-catch [ -t ] [ -r @var{regexp}]
+@end smallexample
+
+Stop when the debuggee catches a C@t{++} exception.  If @var{regexp}
+is given, then only exceptions whose type matches the regular
+expression will be caught.
+
+If @samp{-t} is given, then the catchpoint is enabled only for one
+stop, the catchpoint is automatically deleted after the first event is
+caught.
+
+@subsubheading @value{GDBN} Command
+
+The corresponding @value{GDBN} commands are @samp{catch catch}
+and @samp{tcatch catch} (@pxref{Set Catchpoints}).
+
+@subsubheading Example
+
+@smallexample
+-catch-catch -r exception_type
+^done,bkpt=@{number="1",type="breakpoint",disp="keep",enabled="y",
+  addr="0x00000000004006c0",what="exception catch",
+  catch-type="catch",thread-groups=["i1"],
+  regexp="exception_type",times="0"@}
+(gdb)
+-exec-run
+^running
+(gdb)
+~"\n"
+~"Catchpoint 1 (exception caught), 0x00007ffff7ae00ed
+  in __cxa_begin_catch () from /lib64/libstdc++.so.6\n"
+*stopped,bkptno="1",reason="breakpoint-hit",disp="keep",
+  frame=@{addr="0x00007ffff7ae00ed",func="__cxa_begin_catch",
+  args=[],from="/lib64/libstdc++.so.6",arch="i386:x86-64"@},
+  thread-id="1",stopped-threads="all",core="6"
+(gdb)
+@end smallexample
+
 @c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 @node GDB/MI Program Context
 @section @sc{gdb/mi}  Program Context