range stepping: gdbserver (x86 GNU/Linux)
This patch adds support for range stepping to GDBserver, teaching it about vCont;r. It'd be easy to enable this for all hardware single-step targets without needing the linux_target_ops hook, however, at least PPC needs special care, due to the fact that PPC atomic sequences can't be hardware single-stepped through, a thing which GDBserver doesn't know about. So this leaves the support limited to x86/x86_64. gdb/ 2013-05-23 Pedro Alves <palves@redhat.com> * NEWS: Mention GDBserver range stepping support. gdb/gdbserver/ 2013-05-23 Yao Qi <yao@codesourcery.com> Pedro Alves <palves@redhat.com> * linux-low.c (lwp_in_step_range): New function. (linux_wait_1): If the thread was range stepping and stopped outside the stepping range, report the stop to GDB. Otherwise, continue stepping. Add range stepping debug output. (linux_set_resume_request): Copy the step range from the resume request to the lwp. (linux_supports_range_stepping): New. (linux_target_ops) <supports_range_stepping>: Set to linux_supports_range_stepping. * linux-low.h (struct linux_target_ops) <supports_range_stepping>: New field. (struct lwp_info) <step_range_start, step_range_end>: New fields. * linux-x86-low.c (x86_supports_range_stepping): New. (the_low_target) <supports_range_stepping>: Set to x86_supports_range_stepping. * server.c (handle_v_cont): Handle 'r' action. (handle_v_requests): Append ";r" if the target supports range stepping. * target.h (struct thread_resume) <step_range_start, step_range_end>: New fields. (struct target_ops) <supports_range_stepping>: New field. (target_supports_range_stepping): New macro.
This commit is contained in:
Pedro Alves
parent
c1e36e3e91
commit
c2d6af84da
8 changed files with 141 additions and 12 deletions
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@ -1,3 +1,7 @@
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2013-05-23 Pedro Alves <palves@redhat.com>
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* NEWS: Mention GDBserver range stepping support.
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2013-05-23 Yao Qi <yao@codesourcery.com>
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Pedro Alves <palves@redhat.com>
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5
gdb/NEWS
5
gdb/NEWS
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@ -95,6 +95,11 @@ vCont;r
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stub to step through an address range itself, without GDB
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involvemement at each single-step.
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* New features in the GDB remote stub, GDBserver
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** GDBserver now supports target-assisted range stepping. Currently
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enabled on x86/x86_64 GNU/Linux targets.
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*** Changes in GDB 7.6
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* Target record has been renamed to record-full.
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@ -1,3 +1,30 @@
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2013-05-23 Yao Qi <yao@codesourcery.com>
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Pedro Alves <palves@redhat.com>
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* linux-low.c (lwp_in_step_range): New function.
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(linux_wait_1): If the thread was range stepping and stopped
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outside the stepping range, report the stop to GDB. Otherwise,
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continue stepping. Add range stepping debug output.
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(linux_set_resume_request): Copy the step range from the resume
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request to the lwp.
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(linux_supports_range_stepping): New.
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(linux_target_ops) <supports_range_stepping>: Set to
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linux_supports_range_stepping.
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* linux-low.h (struct linux_target_ops)
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<supports_range_stepping>: New field.
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(struct lwp_info) <step_range_start, step_range_end>: New fields.
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* linux-x86-low.c (x86_supports_range_stepping): New.
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(the_low_target) <supports_range_stepping>: Set to
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x86_supports_range_stepping.
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* server.c (handle_v_cont): Handle 'r' action.
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(handle_v_requests): Append ";r" if the target supports range
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stepping.
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* target.h (struct thread_resume) <step_range_start,
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step_range_end>: New fields.
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(struct target_ops) <supports_range_stepping>:
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New field.
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(target_supports_range_stepping): New macro.
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2013-05-17 Joel Brobecker <brobecker@adacore.com>
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* lynx-low.c (lynx_resume): Fix null_ptid/minus_one_ptid
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@ -276,6 +276,16 @@ supports_fast_tracepoints (void)
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return the_low_target.install_fast_tracepoint_jump_pad != NULL;
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}
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/* True if LWP is stopped in its stepping range. */
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static int
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lwp_in_step_range (struct lwp_info *lwp)
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{
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CORE_ADDR pc = lwp->stop_pc;
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return (pc >= lwp->step_range_start && pc < lwp->step_range_end);
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}
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struct pending_signals
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{
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int signal;
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@ -2337,6 +2347,7 @@ linux_wait_1 (ptid_t ptid,
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int maybe_internal_trap;
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int report_to_gdb;
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int trace_event;
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int in_step_range;
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/* Translate generic target options into linux options. */
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options = __WALL;
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@ -2346,6 +2357,7 @@ linux_wait_1 (ptid_t ptid,
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retry:
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bp_explains_trap = 0;
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trace_event = 0;
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in_step_range = 0;
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ourstatus->kind = TARGET_WAITKIND_IGNORE;
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/* If we were only supposed to resume one thread, only wait for
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@ -2639,18 +2651,24 @@ Check if we're already there.\n",
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goto retry;
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}
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/* If GDB wanted this thread to single step, we always want to
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report the SIGTRAP, and let GDB handle it. Watchpoints should
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always be reported. So should signals we can't explain. A
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SIGTRAP we can't explain could be a GDB breakpoint --- we may or
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not support Z0 breakpoints. If we do, we're be able to handle
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GDB breakpoints on top of internal breakpoints, by handling the
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internal breakpoint and still reporting the event to GDB. If we
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don't, we're out of luck, GDB won't see the breakpoint hit. */
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/* Note that all addresses are always "out of the step range" when
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there's no range to begin with. */
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in_step_range = lwp_in_step_range (event_child);
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/* If GDB wanted this thread to single step, and the thread is out
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of the step range, we always want to report the SIGTRAP, and let
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GDB handle it. Watchpoints should always be reported. So should
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signals we can't explain. A SIGTRAP we can't explain could be a
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GDB breakpoint --- we may or not support Z0 breakpoints. If we
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do, we're be able to handle GDB breakpoints on top of internal
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breakpoints, by handling the internal breakpoint and still
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reporting the event to GDB. If we don't, we're out of luck, GDB
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won't see the breakpoint hit. */
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report_to_gdb = (!maybe_internal_trap
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|| current_inferior->last_resume_kind == resume_step
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|| (current_inferior->last_resume_kind == resume_step
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&& !in_step_range)
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|| event_child->stopped_by_watchpoint
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|| (!step_over_finished
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|| (!step_over_finished && !in_step_range
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&& !bp_explains_trap && !trace_event)
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|| (gdb_breakpoint_here (event_child->stop_pc)
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&& gdb_condition_true_at_breakpoint (event_child->stop_pc)
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@ -2671,6 +2689,11 @@ Check if we're already there.\n",
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fprintf (stderr, "Step-over finished.\n");
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if (trace_event)
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fprintf (stderr, "Tracepoint event.\n");
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if (lwp_in_step_range (event_child))
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fprintf (stderr, "Range stepping pc 0x%s [0x%s, 0x%s).\n",
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paddress (event_child->stop_pc),
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paddress (event_child->step_range_start),
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paddress (event_child->step_range_end));
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}
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/* We're not reporting this breakpoint to GDB, so apply the
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@ -2702,7 +2725,12 @@ Check if we're already there.\n",
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if (debug_threads)
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{
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if (current_inferior->last_resume_kind == resume_step)
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fprintf (stderr, "GDB wanted to single-step, reporting event.\n");
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{
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if (event_child->step_range_start == event_child->step_range_end)
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fprintf (stderr, "GDB wanted to single-step, reporting event.\n");
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else if (!lwp_in_step_range (event_child))
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fprintf (stderr, "Out of step range, reporting event.\n");
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}
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if (event_child->stopped_by_watchpoint)
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fprintf (stderr, "Stopped by watchpoint.\n");
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if (gdb_breakpoint_here (event_child->stop_pc))
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@ -3401,6 +3429,9 @@ linux_set_resume_request (struct inferior_list_entry *entry, void *arg)
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lwp->resume = &r->resume[ndx];
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thread->last_resume_kind = lwp->resume->kind;
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lwp->step_range_start = lwp->resume->step_range_start;
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lwp->step_range_end = lwp->resume->step_range_end;
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/* If we had a deferred signal to report, dequeue one now.
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This can happen if LWP gets more than one signal while
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trying to get out of a jump pad. */
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@ -5094,6 +5125,15 @@ linux_supports_agent (void)
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return 1;
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}
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static int
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linux_supports_range_stepping (void)
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{
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if (*the_low_target.supports_range_stepping == NULL)
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return 0;
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return (*the_low_target.supports_range_stepping) ();
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}
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/* Enumerate spufs IDs for process PID. */
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static int
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spu_enumerate_spu_ids (long pid, unsigned char *buf, CORE_ADDR offset, int len)
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@ -5952,6 +5992,7 @@ static struct target_ops linux_target_ops = {
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NULL,
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NULL,
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#endif
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linux_supports_range_stepping,
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};
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static void
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@ -166,6 +166,8 @@ struct linux_target_ops
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for use as a fast tracepoint. */
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int (*get_min_fast_tracepoint_insn_len) (void);
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/* Returns true if the low target supports range stepping. */
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int (*supports_range_stepping) (void);
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};
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extern struct linux_target_ops the_low_target;
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@ -235,6 +237,12 @@ struct lwp_info
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level on this process was a single-step. */
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int stepping;
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/* Range to single step within. This is a copy of the step range
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passed along the last resume request. See 'struct
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thread_resume'. */
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CORE_ADDR step_range_start; /* Inclusive */
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CORE_ADDR step_range_end; /* Exclusive */
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/* If this flag is set, we need to set the event request flags the
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next time we see this LWP stop. */
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int must_set_ptrace_flags;
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@ -3175,6 +3175,12 @@ x86_emit_ops (void)
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return &i386_emit_ops;
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}
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static int
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x86_supports_range_stepping (void)
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{
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return 1;
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}
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/* This is initialized assuming an amd64 target.
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x86_arch_setup will correct it for i386 or amd64 targets. */
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@ -3214,4 +3220,5 @@ struct linux_target_ops the_low_target =
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x86_install_fast_tracepoint_jump_pad,
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x86_emit_ops,
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x86_get_min_fast_tracepoint_insn_len,
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x86_supports_range_stepping,
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};
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@ -2042,8 +2042,12 @@ handle_v_cont (char *own_buf)
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{
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p++;
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memset (&resume_info[i], 0, sizeof resume_info[i]);
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if (p[0] == 's' || p[0] == 'S')
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resume_info[i].kind = resume_step;
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else if (p[0] == 'r')
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resume_info[i].kind = resume_step;
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else if (p[0] == 'c' || p[0] == 'C')
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resume_info[i].kind = resume_continue;
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else if (p[0] == 't')
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@ -2063,9 +2067,22 @@ handle_v_cont (char *own_buf)
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goto err;
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resume_info[i].sig = gdb_signal_to_host (sig);
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}
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else if (p[0] == 'r')
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{
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char *p1;
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p = p + 1;
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p1 = strchr (p, ',');
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decode_address (&resume_info[i].step_range_start, p, p1 - p);
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p = p1 + 1;
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p1 = strchr (p, ':');
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decode_address (&resume_info[i].step_range_end, p, p1 - p);
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p = p1;
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}
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else
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{
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resume_info[i].sig = 0;
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p = p + 1;
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}
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@ -2311,6 +2328,11 @@ handle_v_requests (char *own_buf, int packet_len, int *new_packet_len)
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if (strncmp (own_buf, "vCont?", 6) == 0)
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{
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strcpy (own_buf, "vCont;c;C;s;S;t");
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if (target_supports_range_stepping ())
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{
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own_buf = own_buf + strlen (own_buf);
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strcpy (own_buf, ";r");
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}
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return;
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}
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}
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@ -57,6 +57,15 @@ struct thread_resume
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linux; SuspendThread on win32). This is a host signal value (not
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enum gdb_signal). */
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int sig;
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/* Range to single step within. Valid only iff KIND is resume_step.
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Single-step once, and then continuing stepping as long as the
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thread stops in this range. (If the range is empty
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[STEP_RANGE_START == STEP_RANGE_END], then this is a single-step
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request.) */
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CORE_ADDR step_range_start; /* Inclusive */
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CORE_ADDR step_range_end; /* Exclusive */
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};
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/* Generally, what has the program done? */
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@ -414,6 +423,8 @@ struct target_ops
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to break a cyclic dependency. */
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void (*read_btrace) (struct btrace_target_info *, struct buffer *, int type);
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/* Return true if target supports range stepping. */
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int (*supports_range_stepping) (void);
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};
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extern struct target_ops *the_target;
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@ -549,6 +560,10 @@ int kill_inferior (int);
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#define target_read_btrace(tinfo, buffer, type) \
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(*the_target->read_btrace) (tinfo, buffer, type)
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#define target_supports_range_stepping() \
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(the_target->supports_range_stepping ? \
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(*the_target->supports_range_stepping) () : 0)
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/* Start non-stop mode, returns 0 on success, -1 on failure. */
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int start_non_stop (int nonstop);
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