From 2f4fcf00399bc0ad5a4fed6b530128e8be4f40da Mon Sep 17 00:00:00 2001 From: Pedro Alves Date: Fri, 10 Jan 2020 20:06:14 +0000 Subject: [PATCH] Require always-non-stop for multi-target resumptions Currently, we can only support resuming multiple targets at the same time if all targets are in non-stop mode (or user-visible all-stop mode with target backend in non-stop mode). This patch makes GDB error out if the user tries to resume more than one target at the same time and one of the resumed targets isn't in non-stop mode: (gdb) info inferiors Num Description Connection Executable 1 process 15303 1 (native) a.out * 2 process 15286 2 (extended-remote :9999) a.out (gdb) set schedule-multiple on (gdb) c Continuing. Connection 2 (extended-remote :9999) does not support multi-target resumption. This is here later in the series instead of in the main multi-target patch because it depends the previous patch, which added process_stratum_target::connection_string(). gdb/ChangeLog: 2020-01-10 Pedro Alves * infrun.c: Include "target-connection.h". (check_multi_target_resumption): New. (proceed): Call it. * target-connection.c (make_target_connection_string): Make extern. * target-connection.h (make_target_connection_string): Declare. --- gdb/ChangeLog | 9 +++++++ gdb/infrun.c | 58 +++++++++++++++++++++++++++++++++++++++++ gdb/target-connection.c | 7 ++--- gdb/target-connection.h | 8 ++++++ 4 files changed, 77 insertions(+), 5 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index d07a792ae5..63c32a0e45 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,12 @@ +2020-01-10 Pedro Alves + + * infrun.c: Include "target-connection.h". + (check_multi_target_resumption): New. + (proceed): Call it. + * target-connection.c (make_target_connection_string): Make + extern. + * target-connection.h (make_target_connection_string): Declare. + 2020-01-10 Pedro Alves * Makefile.in (COMMON_SFILES): Add target-connection.c. diff --git a/gdb/infrun.c b/gdb/infrun.c index 707c053e3f..a0583a8e65 100644 --- a/gdb/infrun.c +++ b/gdb/infrun.c @@ -28,6 +28,7 @@ #include "gdbcore.h" #include "gdbcmd.h" #include "target.h" +#include "target-connection.h" #include "gdbthread.h" #include "annotate.h" #include "symfile.h" @@ -2881,6 +2882,61 @@ commit_resume_all_targets () } } +/* Check that all the targets we're about to resume are in non-stop + mode. Ideally, we'd only care whether all targets support + target-async, but we're not there yet. E.g., stop_all_threads + doesn't know how to handle all-stop targets. Also, the remote + protocol in all-stop mode is synchronous, irrespective of + target-async, which means that things like a breakpoint re-set + triggered by one target would try to read memory from all targets + and fail. */ + +static void +check_multi_target_resumption (process_stratum_target *resume_target) +{ + if (!non_stop && resume_target == nullptr) + { + scoped_restore_current_thread restore_thread; + + /* This is used to track whether we're resuming more than one + target. */ + process_stratum_target *first_connection = nullptr; + + /* The first inferior we see with a target that does not work in + always-non-stop mode. */ + inferior *first_not_non_stop = nullptr; + + for (inferior *inf : all_non_exited_inferiors (resume_target)) + { + switch_to_inferior_no_thread (inf); + + if (!target_has_execution) + continue; + + process_stratum_target *proc_target + = current_inferior ()->process_target(); + + if (!target_is_non_stop_p ()) + first_not_non_stop = inf; + + if (first_connection == nullptr) + first_connection = proc_target; + else if (first_connection != proc_target + && first_not_non_stop != nullptr) + { + switch_to_inferior_no_thread (first_not_non_stop); + + proc_target = current_inferior ()->process_target(); + + error (_("Connection %d (%s) does not support " + "multi-target resumption."), + proc_target->connection_number, + make_target_connection_string (proc_target).c_str ()); + } + } + } +} + /* Basic routine for continuing the program in various fashions. ADDR is the address to resume at, or -1 for resume where stopped. @@ -2931,6 +2987,8 @@ proceed (CORE_ADDR addr, enum gdb_signal siggnal) process_stratum_target *resume_target = user_visible_resume_target (resume_ptid); + check_multi_target_resumption (resume_target); + if (addr == (CORE_ADDR) -1) { if (pc == cur_thr->suspend.stop_pc diff --git a/gdb/target-connection.c b/gdb/target-connection.c index 35c786bc1c..c8c63ab375 100644 --- a/gdb/target-connection.c +++ b/gdb/target-connection.c @@ -53,12 +53,9 @@ connection_list_remove (process_stratum_target *t) t->connection_number = 0; } -/* Make a target connection string for T. This is usually T's - shortname, but it includes the result of - process_stratum_target::connection_string() too if T supports - it. */ +/* See target-connection.h. */ -static std::string +std::string make_target_connection_string (process_stratum_target *t) { if (t->connection_string () != NULL) diff --git a/gdb/target-connection.h b/gdb/target-connection.h index dad3357705..f97e476149 100644 --- a/gdb/target-connection.h +++ b/gdb/target-connection.h @@ -20,6 +20,8 @@ #ifndef TARGET_CONNECTION_H #define TARGET_CONNECTION_H +#include + struct process_stratum_target; /* Add a process target to the connection list, if not already @@ -29,4 +31,10 @@ void connection_list_add (process_stratum_target *t); /* Remove a process target from the connection list. */ void connection_list_remove (process_stratum_target *t); +/* Make a target connection string for T. This is usually T's + shortname, but it includes the result of + process_stratum_target::connection_string() too if T supports + it. */ +std::string make_target_connection_string (process_stratum_target *t); + #endif /* TARGET_CONNECTION_H */ -- 2.34.1