From d20172fc53017cef12d64b21aa2fdac72072558c Mon Sep 17 00:00:00 2001 From: Simon Marchi Date: Wed, 2 Jan 2019 17:31:08 -0500 Subject: [PATCH] Place displaced step data directly in inferior structure This patch moves the per-inferior data related to displaced stepping to be directly in the inferior structure, rather than in a container on the side. On notable difference is that previously, we deleted the state on inferior exit, which guaranteed a clean state if re-using the inferior for a new run or attach. We now need to reset the state manually. At the same time, I changed step_saved_copy to be a gdb::byte_vector, so it is automatically freed on destruction (which should plug the leak reported here [1]). [1] https://sourceware.org/ml/gdb-patches/2018-11/msg00202.html gdb/ChangeLog: * inferior.h (class inferior) : New field. * infrun.h (struct displaced_step_state): Move here from infrun.c. Initialize fields, add constructor. : Remove field. : New method. * infrun.c (struct displaced_step_inferior_state): Move to infrun.h. (displaced_step_inferior_states): Remove. (get_displaced_stepping_state): Adust. (displaced_step_in_progress_any_inferior): Adjust. (displaced_step_in_progress_thread): Adjust. (displaced_step_in_progress): Adjust. (add_displaced_stepping_state): Remove. (get_displaced_step_closure_by_addr): Adjust. (remove_displaced_stepping_state): Remove. (infrun_inferior_exit): Call displaced_step_state.reset. (use_displaced_stepping): Don't check for NULL. (displaced_step_prepare_throw): Call get_displaced_stepping_state. (displaced_step_fixup): Don't check for NULL. (prepare_for_detach): Don't check for NULL. --- gdb/ChangeLog | 24 +++++++++ gdb/inferior.h | 3 ++ gdb/infrun.c | 142 +++++++------------------------------------------ gdb/infrun.h | 44 +++++++++++++++ 4 files changed, 91 insertions(+), 122 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 41889ba92e..c384618830 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,27 @@ +2019-01-02 Simon Marchi + + * inferior.h (class inferior) : New field. + * infrun.h (struct displaced_step_state): Move here from + infrun.c. Initialize fields, add constructor. + : Remove field. + : New method. + * infrun.c (struct displaced_step_inferior_state): Move to + infrun.h. + (displaced_step_inferior_states): Remove. + (get_displaced_stepping_state): Adust. + (displaced_step_in_progress_any_inferior): Adjust. + (displaced_step_in_progress_thread): Adjust. + (displaced_step_in_progress): Adjust. + (add_displaced_stepping_state): Remove. + (get_displaced_step_closure_by_addr): Adjust. + (remove_displaced_stepping_state): Remove. + (infrun_inferior_exit): Call displaced_step_state.reset. + (use_displaced_stepping): Don't check for NULL. + (displaced_step_prepare_throw): Call + get_displaced_stepping_state. + (displaced_step_fixup): Don't check for NULL. + (prepare_for_detach): Don't check for NULL. + 2019-01-02 Philippe Waroquiers * infcall.c (call_function_by_hand_dummy): cleanup/destroy sm diff --git a/gdb/inferior.h b/gdb/inferior.h index 276c442746..a82df1a52a 100644 --- a/gdb/inferior.h +++ b/gdb/inferior.h @@ -503,6 +503,9 @@ public: this gdbarch. */ struct gdbarch *gdbarch = NULL; + /* Data related to displaced stepping. */ + displaced_step_inferior_state displaced_step_state; + /* Per inferior data-pointers required by other GDB modules. */ REGISTRY_FIELDS; }; diff --git a/gdb/infrun.c b/gdb/infrun.c index 00eefabf6e..150288264f 100644 --- a/gdb/infrun.c +++ b/gdb/infrun.c @@ -1476,53 +1476,12 @@ step_over_info_valid_p (void) displaced_step_closure::~displaced_step_closure () = default; -/* Per-inferior displaced stepping state. */ -struct displaced_step_inferior_state -{ - /* The process this displaced step state refers to. */ - inferior *inf; - - /* True if preparing a displaced step ever failed. If so, we won't - try displaced stepping for this inferior again. */ - int failed_before; - - /* If this is not nullptr, this is the thread carrying out a - displaced single-step in process PID. This thread's state will - require fixing up once it has completed its step. */ - thread_info *step_thread; - - /* The architecture the thread had when we stepped it. */ - struct gdbarch *step_gdbarch; - - /* The closure provided gdbarch_displaced_step_copy_insn, to be used - for post-step cleanup. */ - struct displaced_step_closure *step_closure; - - /* The address of the original instruction, and the copy we - made. */ - CORE_ADDR step_original, step_copy; - - /* Saved contents of copy area. */ - gdb_byte *step_saved_copy; -}; - -/* The list of states of processes involved in displaced stepping - presently. */ -static std::forward_list - displaced_step_inferior_states; - /* Get the displaced stepping state of process PID. */ static displaced_step_inferior_state * get_displaced_stepping_state (inferior *inf) { - for (auto *state : displaced_step_inferior_states) - { - if (state->inf == inf) - return state; - } - - return nullptr; + return &inf->displaced_step_state; } /* Returns true if any inferior has a thread doing a displaced @@ -1531,9 +1490,9 @@ get_displaced_stepping_state (inferior *inf) static bool displaced_step_in_progress_any_inferior () { - for (auto *state : displaced_step_inferior_states) + for (inferior *i : all_inferiors ()) { - if (state->step_thread != nullptr) + if (i->displaced_step_state.step_thread != nullptr) return true; } @@ -1546,13 +1505,9 @@ displaced_step_in_progress_any_inferior () static int displaced_step_in_progress_thread (thread_info *thread) { - struct displaced_step_inferior_state *displaced; - gdb_assert (thread != NULL); - displaced = get_displaced_stepping_state (thread->inf); - - return (displaced != NULL && displaced->step_thread == thread); + return get_displaced_stepping_state (thread->inf)->step_thread == thread; } /* Return true if process PID has a thread doing a displaced step. */ @@ -1560,34 +1515,7 @@ displaced_step_in_progress_thread (thread_info *thread) static int displaced_step_in_progress (inferior *inf) { - struct displaced_step_inferior_state *displaced; - - displaced = get_displaced_stepping_state (inf); - if (displaced != NULL && displaced->step_thread != nullptr) - return 1; - - return 0; -} - -/* Add a new displaced stepping state for process PID to the displaced - stepping state list, or return a pointer to an already existing - entry, if it already exists. Never returns NULL. */ - -static displaced_step_inferior_state * -add_displaced_stepping_state (inferior *inf) -{ - displaced_step_inferior_state *state - = get_displaced_stepping_state (inf); - - if (state != nullptr) - return state; - - state = XCNEW (struct displaced_step_inferior_state); - state->inf = inf; - - displaced_step_inferior_states.push_front (state); - - return state; + return get_displaced_stepping_state (inf)->step_thread != nullptr; } /* If inferior is in displaced stepping, and ADDR equals to starting address @@ -1597,42 +1525,21 @@ add_displaced_stepping_state (inferior *inf) struct displaced_step_closure* get_displaced_step_closure_by_addr (CORE_ADDR addr) { - struct displaced_step_inferior_state *displaced + displaced_step_inferior_state *displaced = get_displaced_stepping_state (current_inferior ()); /* If checking the mode of displaced instruction in copy area. */ - if (displaced != NULL - && displaced->step_thread != nullptr + if (displaced->step_thread != nullptr && displaced->step_copy == addr) return displaced->step_closure; return NULL; } -/* Remove the displaced stepping state of process PID. */ - -static void -remove_displaced_stepping_state (inferior *inf) -{ - gdb_assert (inf != nullptr); - - displaced_step_inferior_states.remove_if - ([inf] (displaced_step_inferior_state *state) - { - if (state->inf == inf) - { - xfree (state); - return true; - } - else - return false; - }); -} - static void infrun_inferior_exit (struct inferior *inf) { - remove_displaced_stepping_state (inf); + inf->displaced_step_state.reset (); } /* If ON, and the architecture supports it, GDB will use displaced @@ -1669,17 +1576,15 @@ use_displaced_stepping (struct thread_info *tp) { struct regcache *regcache = get_thread_regcache (tp); struct gdbarch *gdbarch = regcache->arch (); - struct displaced_step_inferior_state *displaced_state; - - displaced_state = get_displaced_stepping_state (tp->inf); + displaced_step_inferior_state *displaced_state + = get_displaced_stepping_state (tp->inf); return (((can_use_displaced_stepping == AUTO_BOOLEAN_AUTO && target_is_non_stop_p ()) || can_use_displaced_stepping == AUTO_BOOLEAN_TRUE) && gdbarch_displaced_step_copy_insn_p (gdbarch) && find_record_target () == NULL - && (displaced_state == NULL - || !displaced_state->failed_before)); + && !displaced_state->failed_before); } /* Clean out any stray displaced stepping state. */ @@ -1734,14 +1639,12 @@ displaced_step_dump_bytes (struct ui_file *file, static int displaced_step_prepare_throw (thread_info *tp) { - struct cleanup *ignore_cleanups; regcache *regcache = get_thread_regcache (tp); struct gdbarch *gdbarch = regcache->arch (); const address_space *aspace = regcache->aspace (); CORE_ADDR original, copy; ULONGEST len; struct displaced_step_closure *closure; - struct displaced_step_inferior_state *displaced; int status; /* We should never reach this function if the architecture does not @@ -1760,7 +1663,8 @@ displaced_step_prepare_throw (thread_info *tp) /* We have to displaced step one thread at a time, as we only have access to a single scratch space per inferior. */ - displaced = add_displaced_stepping_state (tp->inf); + displaced_step_inferior_state *displaced + = get_displaced_stepping_state (tp->inf); if (displaced->step_thread != nullptr) { @@ -1816,10 +1720,8 @@ displaced_step_prepare_throw (thread_info *tp) } /* Save the original contents of the copy area. */ - displaced->step_saved_copy = (gdb_byte *) xmalloc (len); - ignore_cleanups = make_cleanup (free_current_contents, - &displaced->step_saved_copy); - status = target_read_memory (copy, displaced->step_saved_copy, len); + displaced->step_saved_copy.resize (len); + status = target_read_memory (copy, displaced->step_saved_copy.data (), len); if (status != 0) throw_error (MEMORY_ERROR, _("Error accessing memory address %s (%s) for " @@ -1830,7 +1732,7 @@ displaced_step_prepare_throw (thread_info *tp) fprintf_unfiltered (gdb_stdlog, "displaced: saved %s: ", paddress (gdbarch, copy)); displaced_step_dump_bytes (gdb_stdlog, - displaced->step_saved_copy, + displaced->step_saved_copy.data (), len); }; @@ -1841,7 +1743,6 @@ displaced_step_prepare_throw (thread_info *tp) /* The architecture doesn't know how or want to displaced step this instruction or instruction sequence. Fallback to stepping over the breakpoint in-line. */ - do_cleanups (ignore_cleanups); return -1; } @@ -1853,7 +1754,8 @@ displaced_step_prepare_throw (thread_info *tp) displaced->step_original = original; displaced->step_copy = copy; - make_cleanup (displaced_step_clear_cleanup, displaced); + cleanup *ignore_cleanups + = make_cleanup (displaced_step_clear_cleanup, displaced); /* Resume execution at the copy. */ regcache_write_pc (regcache, copy); @@ -1931,7 +1833,7 @@ displaced_step_restore (struct displaced_step_inferior_state *displaced, ULONGEST len = gdbarch_max_insn_length (displaced->step_gdbarch); write_memory_ptid (ptid, displaced->step_copy, - displaced->step_saved_copy, len); + displaced->step_saved_copy.data (), len); if (debug_displaced) fprintf_unfiltered (gdb_stdlog, "displaced: restored %s %s\n", target_pid_to_str (ptid), @@ -1953,10 +1855,6 @@ displaced_step_fixup (thread_info *event_thread, enum gdb_signal signal) = get_displaced_stepping_state (event_thread->inf); int ret; - /* Was any thread of this process doing a displaced step? */ - if (displaced == NULL) - return 0; - /* Was this event for the thread we displaced? */ if (displaced->step_thread != event_thread) return 0; @@ -3577,7 +3475,7 @@ prepare_for_detach (void) /* Is any thread of this process displaced stepping? If not, there's nothing else to do. */ - if (displaced == NULL || displaced->step_thread == nullptr) + if (displaced->step_thread == nullptr) return; if (debug_infrun) diff --git a/gdb/infrun.h b/gdb/infrun.h index 0d1309b100..8f61b75c15 100644 --- a/gdb/infrun.h +++ b/gdb/infrun.h @@ -258,4 +258,48 @@ struct buf_displaced_step_closure : displaced_step_closure gdb::byte_vector buf; }; +/* Per-inferior displaced stepping state. */ +struct displaced_step_inferior_state +{ + displaced_step_inferior_state () + { + reset (); + } + + /* Put this object back in its original state. */ + void reset () + { + failed_before = 0; + step_thread = nullptr; + step_gdbarch = nullptr; + step_closure = nullptr; + step_original = 0; + step_copy = 0; + step_saved_copy.clear (); + } + + /* True if preparing a displaced step ever failed. If so, we won't + try displaced stepping for this inferior again. */ + int failed_before; + + /* If this is not nullptr, this is the thread carrying out a + displaced single-step in process PID. This thread's state will + require fixing up once it has completed its step. */ + thread_info *step_thread; + + /* The architecture the thread had when we stepped it. */ + gdbarch *step_gdbarch; + + /* The closure provided gdbarch_displaced_step_copy_insn, to be used + for post-step cleanup. */ + displaced_step_closure *step_closure; + + /* The address of the original instruction, and the copy we + made. */ + CORE_ADDR step_original, step_copy; + + /* Saved contents of copy area. */ + gdb::byte_vector step_saved_copy; +}; + #endif /* INFRUN_H */ -- 2.34.1