From patchwork Tue Mar 5 18:43:38 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pedro Alves X-Patchwork-Id: 31723 Received: (qmail 6414 invoked by alias); 5 Mar 2019 18:43:54 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org Delivered-To: mailing list gdb-patches@sourceware.org Received: (qmail 6296 invoked by uid 89); 5 Mar 2019 18:43:54 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-26.9 required=5.0 tests=BAYES_00, GIT_PATCH_0, GIT_PATCH_1, GIT_PATCH_2, GIT_PATCH_3, SPF_HELO_PASS autolearn=ham version=3.3.2 spammy=solo, 1819, convince, forks X-HELO: mx1.redhat.com Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Tue, 05 Mar 2019 18:43:51 +0000 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id D6FEA81F2F for ; Tue, 5 Mar 2019 18:43:49 +0000 (UTC) Received: from localhost.localdomain (ovpn04.gateway.prod.ext.ams2.redhat.com [10.39.146.4]) by smtp.corp.redhat.com (Postfix) with ESMTP id 25CC85D782 for ; Tue, 5 Mar 2019 18:43:48 +0000 (UTC) From: Pedro Alves To: gdb-patches@sourceware.org Subject: [PATCH 2/4] C++ify fork_info, use std::list Date: Tue, 5 Mar 2019 18:43:38 +0000 Message-Id: <20190305184340.26768-3-palves@redhat.com> In-Reply-To: <20190305184340.26768-1-palves@redhat.com> References: <20190305184340.26768-1-palves@redhat.com> - Convert new_fork and free_fork to fork_info ctor/dtor. - Use std::list. gdb/ChangeLog: yyyy-mm-dd Pedro Alves * linux-fork.c: Include . (fork_list): Now a std::list instance. (fork_info): Add ctor, dtor, and in-class initialize all fields. (forks_exist_p, find_last_fork): Adjust. (new_fork): Delete. (one_fork_p): New. (add_fork): Adjust. (free_fork): Delete, folded into fork_info::~fork_info(). (delete_fork, find_fork_ptid, find_fork_id, find_fork_pid): Adjust. (init_fork_list): Delete. (linux_fork_killall, linux_fork_mourn_inferior) (linux_fork_detach, info_checkpoints_command): Adjust. (_initialize_linux_fork): No longer call init_fork_list. --- gdb/linux-fork.c | 261 +++++++++++++++++++++++-------------------------------- 1 file changed, 108 insertions(+), 153 deletions(-) diff --git a/gdb/linux-fork.c b/gdb/linux-fork.c index a748deaa3a..1c7b7ca123 100644 --- a/gdb/linux-fork.c +++ b/gdb/linux-fork.c @@ -35,30 +35,66 @@ #include #include -struct fork_info *fork_list; -static int highest_fork_num; +#include /* Fork list data structure: */ struct fork_info { - struct fork_info *next; - ptid_t ptid; - ptid_t parent_ptid; - int num; /* Convenient handle (GDB fork id). */ - readonly_detached_regcache *savedregs; /* Convenient for info fork, saves - having to actually switch contexts. */ - CORE_ADDR pc; - int clobber_regs; /* True if we should restore saved regs. */ - off_t *filepos; /* Set of open file descriptors' offsets. */ - int maxfd; + explicit fork_info (pid_t pid) + : ptid (pid, pid, 0) + { + } + + ~fork_info () + { + /* Notes on step-resume breakpoints: since this is a concern for + threads, let's convince ourselves that it's not a concern for + forks. There are two ways for a fork_info to be created. + First, by the checkpoint command, in which case we're at a gdb + prompt and there can't be any step-resume breakpoint. Second, + by a fork in the user program, in which case we *may* have + stepped into the fork call, but regardless of whether we follow + the parent or the child, we will return to the same place and + the step-resume breakpoint, if any, will take care of itself as + usual. And unlike threads, we do not save a private copy of + the step-resume breakpoint -- so we're OK. */ + + if (savedregs) + delete savedregs; + if (filepos) + xfree (filepos); + } + + ptid_t ptid = null_ptid; + ptid_t parent_ptid = null_ptid; + + /* Convenient handle (GDB fork id). */ + int num = 0; + + /* Convenient for info fork, saves having to actually switch + contexts. */ + readonly_detached_regcache *savedregs = nullptr; + + CORE_ADDR pc = 0; + + /* True if we should restore saved regs. */ + int clobber_regs = 0; + + /* Set of open file descriptors' offsets. */ + off_t *filepos = nullptr; + + int maxfd = 0; }; +static std::list fork_list; +static int highest_fork_num; + /* Fork list methods: */ int forks_exist_p (void) { - return (fork_list != NULL); + return !fork_list.empty (); } /* Return the last fork in the list. */ @@ -66,26 +102,19 @@ forks_exist_p (void) static struct fork_info * find_last_fork (void) { - struct fork_info *last; - - if (fork_list == NULL) + if (fork_list.empty ()) return NULL; - for (last = fork_list; last->next != NULL; last = last->next) - ; - return last; + return &fork_list.back (); } -/* Allocate a new fork. */ +/* Return true iff there's one fork in the list. */ -static struct fork_info * -new_fork (pid_t pid) +static bool +one_fork_p () { - struct fork_info *fp; - - fp = XCNEW (struct fork_info); - fp->ptid = ptid_t (pid, pid, 0); - return fp; + return (!fork_list.empty () + && &fork_list.front () == &fork_list.back ()); } /* Add a new fork to the internal fork list. */ @@ -93,93 +122,46 @@ new_fork (pid_t pid) void add_fork (pid_t pid) { - struct fork_info *fp = new_fork (pid); - - if (fork_list == NULL) - { - fork_list = fp; - highest_fork_num = 0; - } - else - { - struct fork_info *last = find_last_fork (); + fork_list.emplace_back (pid); - last->next = fp; - } + if (one_fork_p ()) + highest_fork_num = 0; + fork_info *fp = &fork_list.back (); fp->num = ++highest_fork_num; } -static void -free_fork (struct fork_info *fp) -{ - /* Notes on step-resume breakpoints: since this is a concern for - threads, let's convince ourselves that it's not a concern for - forks. There are two ways for a fork_info to be created. First, - by the checkpoint command, in which case we're at a gdb prompt - and there can't be any step-resume breakpoint. Second, by a fork - in the user program, in which case we *may* have stepped into the - fork call, but regardless of whether we follow the parent or the - child, we will return to the same place and the step-resume - breakpoint, if any, will take care of itself as usual. And - unlike threads, we do not save a private copy of the step-resume - breakpoint -- so we're OK. */ - - if (fp) - { - if (fp->savedregs) - delete fp->savedregs; - if (fp->filepos) - xfree (fp->filepos); - xfree (fp); - } -} - static void delete_fork (ptid_t ptid) { - struct fork_info *fp, *fpprev; - - fpprev = NULL; - linux_target->low_forget_process (ptid.pid ()); - for (fp = fork_list; fp; fpprev = fp, fp = fp->next) - if (fp->ptid == ptid) - break; - - if (!fp) - return; - - if (fpprev) - fpprev->next = fp->next; - else - fork_list = fp->next; - - free_fork (fp); + for (auto it = fork_list.begin (); it != fork_list.end (); ++it) + if (it->ptid == ptid) + { + fork_list.erase (it); - /* Special case: if there is now only one process in the list, - and if it is (hopefully!) the current inferior_ptid, then - remove it, leaving the list empty -- we're now down to the - default case of debugging a single process. */ - if (fork_list != NULL && fork_list->next == NULL && - fork_list->ptid == inferior_ptid) - { - /* Last fork -- delete from list and handle as solo process - (should be a safe recursion). */ - delete_fork (inferior_ptid); - } + /* Special case: if there is now only one process in the list, + and if it is (hopefully!) the current inferior_ptid, then + remove it, leaving the list empty -- we're now down to the + default case of debugging a single process. */ + if (one_fork_p () && fork_list.front ().ptid == inferior_ptid) + { + /* Last fork -- delete from list and handle as solo + process (should be a safe recursion). */ + delete_fork (inferior_ptid); + } + return; + } } /* Find a fork_info by matching PTID. */ static struct fork_info * find_fork_ptid (ptid_t ptid) { - struct fork_info *fp; - - for (fp = fork_list; fp; fp = fp->next) - if (fp->ptid == ptid) - return fp; + for (fork_info &fi : fork_list) + if (fi.ptid == ptid) + return &fi; return NULL; } @@ -188,11 +170,9 @@ find_fork_ptid (ptid_t ptid) static struct fork_info * find_fork_id (int num) { - struct fork_info *fp; - - for (fp = fork_list; fp; fp = fp->next) - if (fp->num == num) - return fp; + for (fork_info &fi : fork_list) + if (fi.num == num) + return &fi; return NULL; } @@ -201,11 +181,9 @@ find_fork_id (int num) extern struct fork_info * find_fork_pid (pid_t pid) { - struct fork_info *fp; - - for (fp = fork_list; fp; fp = fp->next) - if (pid == fp->ptid.pid ()) - return fp; + for (fork_info &fi : fork_list) + if (pid == fi.ptid.pid ()) + return &fi; return NULL; } @@ -220,23 +198,6 @@ fork_id_to_ptid (int num) return ptid_t (-1); } -static void -init_fork_list (void) -{ - struct fork_info *fp, *fpnext; - - if (!fork_list) - return; - - for (fp = fork_list; fp; fp = fpnext) - { - fpnext = fp->next; - free_fork (fp); - } - - fork_list = NULL; -} - /* Fork list <-> gdb interface. */ /* Utility function for fork_load/fork_save. @@ -350,13 +311,12 @@ linux_fork_killall (void) status for it) -- however any process may be a child or a parent, so may get a SIGCHLD from a previously killed child. Wait them all out. */ - struct fork_info *fp; - pid_t pid, ret; - int status; - for (fp = fork_list; fp; fp = fp->next) + for (fork_info &fi : fork_list) { - pid = fp->ptid.pid (); + pid_t pid = fi.ptid.pid (); + int status; + pid_t ret; do { /* Use SIGKILL instead of PTRACE_KILL because the former works even if the thread is running, while the later doesn't. */ @@ -367,7 +327,9 @@ linux_fork_killall (void) died. MVS comment cut-and-pasted from linux-nat. */ } while (ret == pid && WIFSTOPPED (status)); } - init_fork_list (); /* Clear list, prepare to start fresh. */ + + /* Clear list, prepare to start fresh. */ + fork_list.clear (); } /* The current inferior_ptid has exited, but there are other viable @@ -394,7 +356,7 @@ linux_fork_mourn_inferior (void) /* There should still be a fork - if there's only one left, delete_fork won't remove it, because we haven't updated inferior_ptid yet. */ - gdb_assert (fork_list); + gdb_assert (!fork_list.empty ()); last = find_last_fork (); fork_load_infrun_state (last); @@ -402,7 +364,7 @@ linux_fork_mourn_inferior (void) target_pid_to_str (inferior_ptid)); /* If there's only one fork, switch back to non-fork mode. */ - if (fork_list->next == NULL) + if (one_fork_p ()) delete_fork (inferior_ptid); } @@ -425,16 +387,16 @@ linux_fork_detach (int from_tty) /* There should still be a fork - if there's only one left, delete_fork won't remove it, because we haven't updated inferior_ptid yet. */ - gdb_assert (fork_list); + gdb_assert (!fork_list.empty ()); - fork_load_infrun_state (fork_list); + fork_load_infrun_state (&fork_list.front ()); if (from_tty) printf_filtered (_("[Switching to %s]\n"), target_pid_to_str (inferior_ptid)); /* If there's only one fork, switch back to non-fork mode. */ - if (fork_list->next == NULL) + if (one_fork_p ()) delete_fork (inferior_ptid); } @@ -606,34 +568,31 @@ static void info_checkpoints_command (const char *arg, int from_tty) { struct gdbarch *gdbarch = get_current_arch (); - struct symtab_and_line sal; - struct fork_info *fp; - ULONGEST pc; int requested = -1; - struct fork_info *printed = NULL; + const fork_info *printed = NULL; if (arg && *arg) requested = (int) parse_and_eval_long (arg); - for (fp = fork_list; fp; fp = fp->next) + for (const fork_info &fi : fork_list) { - if (requested > 0 && fp->num != requested) + if (requested > 0 && fi.num != requested) continue; - printed = fp; - if (fp->ptid == inferior_ptid) + printed = &fi; + if (fi.ptid == inferior_ptid) printf_filtered ("* "); else printf_filtered (" "); - pc = fp->pc; - printf_filtered ("%d %s", fp->num, target_pid_to_str (fp->ptid)); - if (fp->num == 0) + ULONGEST pc = fi.pc; + printf_filtered ("%d %s", fi.num, target_pid_to_str (fi.ptid)); + if (fi.num == 0) printf_filtered (_(" (main process)")); printf_filtered (_(" at ")); fputs_filtered (paddress (gdbarch, pc), gdb_stdout); - sal = find_pc_line (pc, 0); + symtab_and_line sal = find_pc_line (pc, 0); if (sal.symtab) printf_filtered (_(", file %s"), symtab_to_filename_for_display (sal.symtab)); @@ -762,14 +721,12 @@ checkpoint_command (const char *args, int from_tty) if (!fp) error (_("Failed to find new fork")); - if (fork_list->next == NULL) + if (one_fork_p ()) { /* Special case -- if this is the first fork in the list (the list was hitherto empty), then add inferior_ptid first, as a special zeroeth fork id. */ - fork_info *first = new_fork (inferior_ptid.pid ()); - first->next = fork_list; - fork_list = first; + fork_list.emplace_front (inferior_ptid.pid ()); } fork_save_infrun_state (fp, 1); @@ -816,8 +773,6 @@ restart_command (const char *args, int from_tty) void _initialize_linux_fork (void) { - init_fork_list (); - /* Checkpoint command: create a fork of the inferior process and set it aside for later debugging. */