gdb/mi: fix breakpoint script field output

The "script" field, output whenever information about a breakpoint with
commands is output, uses wrong MI syntax.

    $ ./gdb -nx -q --data-directory=data-directory -x script -i mi
    =thread-group-added,id="i1"
    =breakpoint-created,bkpt={number="1",type="breakpoint",disp="keep",enabled="y",addr="0x000000000000111d",func="main",file="test.c",fullname="/home/simark/build/binutils-gdb-one-target/gdb/test.c",line="3",thread-groups=["i1"],times="0",original-location="main"}
    =breakpoint-modified,bkpt={number="1",type="breakpoint",disp="keep",enabled="y",addr="0x000000000000111d",func="main",file="test.c",fullname="/home/simark/build/binutils-gdb-one-target/gdb/test.c",line="3",thread-groups=["i1"],times="0",script={"aaa","bbb","ccc"},original-location="main"}
    (gdb)
    -break-info
    ^done,BreakpointTable={nr_rows="1",nr_cols="6",hdr=[{width="7",alignment="-1",col_name="number",colhdr="Num"},{width="14",alignment="-1",col_name="type",colhdr="Type"},{width="4",alignment="-1",col_name="disp",colhdr="Disp"},{width="3",alignment="-1",col_name="enabled",colhdr="Enb"},{width="18",alignment="-1",col_name="addr",colhdr="Address"},{width="40",alignment="2",col_name="what",colhdr="What"}],body=[bkpt={number="1",type="breakpoint",disp="keep",enabled="y",addr="0x000000000000111d",func="main",file="test.c",fullname="/home/simark/build/binutils-gdb-one-target/gdb/test.c",line="3",thread-groups=["i1"],times="0",script={"aaa","bbb","ccc"},original-location="main"}]}
    (gdb)

In both the =breakpoint-modified and -break-info output, we have:

     script={"aaa","bbb","ccc"}

According to the output syntax [1], curly braces means tuple, and a
tuple contains key=value pairs.  This looks like it should be a list,
but uses curly braces by mistake.  This would make more sense:

    script=["aaa","bbb","ccc"]

Fix it, keeping the backwards compatibility by introducing a new MI
version (MI4), in exactly the same way as was done when fixing
multi-locations breakpoint output in [2].

 - Add a fix_breakpoint_script_output uiout flag.  MI uiouts will use
   this flag if the version is >= 4.
 - Add a fix_breakpoint_script_output_globally variable and the
   -fix-breakpoint-script-output MI command to set it, if frontends want
   to use the fixed output for this without using the newer MI version.
 - When emitting the script field, use list instead of tuple, if we want
   the fixed output (depending on the two criteria above)
 -

[1] https://sourceware.org/gdb/onlinedocs/gdb/GDB_002fMI-Output-Syntax.html#GDB_002fMI-Output-Syntax
[2] https://gitlab.com/gnutools/binutils-gdb/-/commit/b4be1b0648608a2578bbed39841c8ee411773edd

Change-Id: I7113c6892832c8d6805badb06ce42496677e2242
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=24285

6 files changed, 42 insertions, 4 deletions

diff --git a/gdb/mi/mi-cmds.c b/gdb/mi/mi-cmds.c
index 0571469..852f8c0 100644
--- a/gdb/mi/mi-cmds.c
+++ b/gdb/mi/mi-cmds.c
@@ -282,6 +282,8 @@ add_builtin_mi_commands ()
   add_mi_cmd_mi ("file-list-shared-libraries",
      mi_cmd_file_list_shared_libraries),
   add_mi_cmd_cli ("file-symbol-file", "symbol-file", 1);
+  add_mi_cmd_mi ("fix-breakpoint-script-output",
+		 mi_cmd_fix_breakpoint_script_output),
   add_mi_cmd_mi ("fix-multi-location-breakpoint-output",
 		 mi_cmd_fix_multi_location_breakpoint_output),
   add_mi_cmd_mi ("gdb-exit", mi_cmd_gdb_exit);
diff --git a/gdb/mi/mi-interp.c b/gdb/mi/mi-interp.c
index ae15177..368c13f 100644
--- a/gdb/mi/mi-interp.c
+++ b/gdb/mi/mi-interp.c
@@ -1343,6 +1343,7 @@ _initialize_mi_interp ()
   interp_factory_register (INTERP_MI1, mi_interp_factory);
   interp_factory_register (INTERP_MI2, mi_interp_factory);
   interp_factory_register (INTERP_MI3, mi_interp_factory);
+  interp_factory_register (INTERP_MI4, mi_interp_factory);
   interp_factory_register (INTERP_MI, mi_interp_factory);
 
   gdb::observers::signal_received.attach (mi_on_signal_received, "mi-interp");
diff --git a/gdb/mi/mi-main.c b/gdb/mi/mi-main.c
index 68868e4..b758f39 100644
--- a/gdb/mi/mi-main.c
+++ b/gdb/mi/mi-main.c
@@ -1865,7 +1865,8 @@ captured_mi_execute_command (struct ui_out *uiout, struct mi_parse *context)
 	if (current_interp_named_p (INTERP_MI)
 	    || current_interp_named_p (INTERP_MI1)
 	    || current_interp_named_p (INTERP_MI2)
-	    || current_interp_named_p (INTERP_MI3))
+	    || current_interp_named_p (INTERP_MI3)
+	    || current_interp_named_p (INTERP_MI4))
 	  {
 	    if (!running_result_record_printed)
 	      {
@@ -2709,6 +2710,14 @@ mi_cmd_fix_multi_location_breakpoint_output (const char *command, char **argv,
   fix_multi_location_breakpoint_output_globally = true;
 }
 
+/* See mi/mi-main.h.  */
+
+void
+mi_cmd_fix_breakpoint_script_output (const char *command, char **argv, int argc)
+{
+  fix_breakpoint_script_output_globally = true;
+}
+
 /* Implement the "-complete" command.  */
 
 void
diff --git a/gdb/mi/mi-main.h b/gdb/mi/mi-main.h
index 8e4fb63..0ac8368 100644
--- a/gdb/mi/mi-main.h
+++ b/gdb/mi/mi-main.h
@@ -71,4 +71,9 @@ extern void mi_execute_cli_command (const char *cmd, bool args_p,
 extern void mi_cmd_fix_multi_location_breakpoint_output (const char *command,
 							 char **argv, int argc);
 
+/* Implementation of -fix-breakpoint-script-output.  */
+
+extern void mi_cmd_fix_breakpoint_script_output (const char *command,
+						 char **argv, int argc);
+
 #endif /* MI_MI_MAIN_H */
diff --git a/gdb/mi/mi-out.c b/gdb/mi/mi-out.c
index 567ef83..eedc5f7 100644
--- a/gdb/mi/mi-out.c
+++ b/gdb/mi/mi-out.c
@@ -288,8 +288,7 @@ mi_ui_out::version ()
 /* Constructor for an `mi_out_data' object.  */
 
 mi_ui_out::mi_ui_out (int mi_version)
-: ui_out (mi_version >= 3
-	  ? fix_multi_location_breakpoint_output : (ui_out_flag) 0),
+: ui_out (make_flags (mi_version)),
   m_suppress_field_separator (false),
   m_suppress_output (false),
   m_mi_version (mi_version)
@@ -307,7 +306,10 @@ mi_ui_out::~mi_ui_out ()
 mi_ui_out *
 mi_out_new (const char *mi_version)
 {
-  if (streq (mi_version, INTERP_MI3) ||  streq (mi_version, INTERP_MI))
+  if (streq (mi_version, INTERP_MI4) ||  streq (mi_version, INTERP_MI))
+    return new mi_ui_out (4);
+
+  if (streq (mi_version, INTERP_MI3))
     return new mi_ui_out (3);
 
   if (streq (mi_version, INTERP_MI2))
diff --git a/gdb/mi/mi-out.h b/gdb/mi/mi-out.h
index 8f2f2d8..36d7e42 100644
--- a/gdb/mi/mi-out.h
+++ b/gdb/mi/mi-out.h
@@ -106,6 +106,25 @@ private:
      redirected.  */
   string_file *main_stream ();
 
+  /* Helper for the constructor, deduce ui_out_flags for the given
+     MI_VERSION.  */
+  static ui_out_flags make_flags (int mi_version)
+  {
+    ui_out_flags flags = 0;
+
+    /* In MI version 2 and below, multi-location breakpoints had a wrong
+       syntax.  It is fixed in version 3.  */
+    if (mi_version >= 3)
+      flags |= fix_multi_location_breakpoint_output;
+
+    /* In MI version 3 and below, the "script" field in breakpoint output
+       had a wrong syntax.  It is fixed in version 4.  */
+    if (mi_version >= 4)
+      flags |= fix_breakpoint_script_output;
+
+    return flags;
+  }
+
   bool m_suppress_field_separator;
   bool m_suppress_output;
   int m_mi_version;