From 3cdc2d7e66ab6a48014dcd425c88cfd42a964321 Mon Sep 17 00:00:00 2001 From: Mihails Strasuns Date: Tue, 3 Dec 2019 13:13:25 +0100 Subject: [PATCH] gdb, breakpoint: add breakpoint location debugging logs Add new commands: set debug breakpoint on|off show debug breakpoint This patch introduces new debugging information that prints breakpoint location insertion and removal flow. The debug output looks like: ~~~ (gdb) set debug breakpoint on (gdb) disassemble main Dump of assembler code for function main: 0x0000555555555129 <+0>: endbr64 0x000055555555512d <+4>: push %rbp 0x000055555555512e <+5>: mov %rsp,%rbp => 0x0000555555555131 <+8>: mov $0x0,%eax 0x0000555555555136 <+13>: pop %rbp 0x0000555555555137 <+14>: ret End of assembler dump. (gdb) break *0x0000555555555137 Breakpoint 2 at 0x555555555137: file main.c, line 4. [breakpoint] update_global_location_list: insert_mode = UGLL_MAY_INSERT (gdb) c Continuing. [breakpoint] update_global_location_list: insert_mode = UGLL_INSERT [breakpoint] insert_bp_location: Breakpoint 2 (0x5565daddb1e0) at address 0x555555555137 in main at main.c:4 [breakpoint] insert_bp_location: Breakpoint -2 (0x5565dab51c10) at address 0x7ffff7fd37b5 [breakpoint] insert_bp_location: Breakpoint -5 (0x5565dab68f30) at address 0x7ffff7fe509e [breakpoint] insert_bp_location: Breakpoint -7 (0x5565dab694f0) at address 0x7ffff7fe63f4 [breakpoint] remove_breakpoint_1: Breakpoint 2 (0x5565daddb1e0) at address 0x555555555137 in main at main.c:4 due to regular remove [breakpoint] remove_breakpoint_1: Breakpoint -2 (0x5565dab51c10) at address 0x7ffff7fd37b5 due to regular remove [breakpoint] remove_breakpoint_1: Breakpoint -5 (0x5565dab68f30) at address 0x7ffff7fe509e due to regular remove [breakpoint] remove_breakpoint_1: Breakpoint -7 (0x5565dab694f0) at address 0x7ffff7fe63f4 due to regular remove Breakpoint 2, 0x0000555555555137 in main () at main.c:4 4 } ~~~ Co-Authored-By: Christina Schimpe --- gdb/NEWS | 4 ++ gdb/breakpoint.c | 110 ++++++++++++++++++++++++++++++++++++++++++++ gdb/breakpoint.h | 4 ++ gdb/doc/gdb.texinfo | 8 ++++ 4 files changed, 126 insertions(+) diff --git a/gdb/NEWS b/gdb/NEWS index 3f414a54fb7..ef2b3b3a4f5 100644 --- a/gdb/NEWS +++ b/gdb/NEWS @@ -100,6 +100,10 @@ * New commands +set debug breakpoint on|off + show debug breakpoint + Print additional debug messages about breakpoint insertion and removal. + maintenance print record-instruction [ N ] Print the recorded information for a given instruction. If N is not given prints how GDB would undo the last instruction executed. If N is negative, diff --git a/gdb/breakpoint.c b/gdb/breakpoint.c index 93634bd7e51..e08f3444a65 100644 --- a/gdb/breakpoint.c +++ b/gdb/breakpoint.c @@ -83,6 +83,7 @@ #include "progspace-and-thread.h" #include "gdbsupport/array-view.h" #include "gdbsupport/gdb_optional.h" +#include "gdbsupport/common-utils.h" /* Prototypes for local functions. */ @@ -200,6 +201,68 @@ enum ugll_insert_mode UGLL_INSERT }; +/* Return a textual version of INSERT_MODE. */ + +static const char * +ugll_insert_mode_text (ugll_insert_mode insert_mode) +{ +/* Make sure the compiler warns if a new ugll_insert_mode enumerator is added + but not handled here. */ +DIAGNOSTIC_PUSH +DIAGNOSTIC_ERROR_SWITCH + switch (insert_mode) + { + case UGLL_DONT_INSERT: + return "UGLL_DONT_INSERT"; + case UGLL_MAY_INSERT: + return "UGLL_MAY_INSERT"; + case UGLL_INSERT: + return "UGLL_INSERT"; + } +DIAGNOSTIC_POP + + gdb_assert_not_reached ("must handle all enum values"); +} + +/* Return a textual version of REASON. */ + +static const char * +remove_bp_reason_str (remove_bp_reason reason) +{ +/* Make sure the compiler warns if a new remove_bp_reason enumerator is added + but not handled here. */ +DIAGNOSTIC_PUSH +DIAGNOSTIC_ERROR_SWITCH + switch (reason) + { + case REMOVE_BREAKPOINT: + return "regular remove"; + case DETACH_BREAKPOINT: + return "detach"; + } +DIAGNOSTIC_POP + + gdb_assert_not_reached ("must handle all enum values"); +} + +/* Return a textual version of breakpoint location BL describing number, + location and address. */ + +static std::string +breakpoint_location_address_str (const bp_location *bl) +{ + std::string str = string_printf ("Breakpoint %d (%s) at address %s", + bl->owner->number, + host_address_to_string (bl), + paddress (bl->gdbarch, bl->address)); + + std::string loc_string = bl->to_string (); + if (!loc_string.empty ()) + str += string_printf (" %s", loc_string.c_str ()); + + return str; +} + static void update_global_location_list (enum ugll_insert_mode); static void update_global_location_list_nothrow (enum ugll_insert_mode); @@ -510,6 +573,22 @@ show_always_inserted_mode (struct ui_file *file, int from_tty, value); } +/* True if breakpoint debug output is enabled. */ +static bool debug_breakpoint = false; + +/* Print a "breakpoint" debug statement. */ +#define breakpoint_debug_printf(fmt, ...) \ + debug_prefixed_printf_cond (debug_breakpoint, "breakpoint", fmt, \ + ##__VA_ARGS__) + +/* "show debug breakpoint" implementation. */ +static void +show_debug_breakpoint (struct ui_file *file, int from_tty, + struct cmd_list_element *c, const char *value) +{ + gdb_printf (file, _("Breakpoint location debugging is %s.\n"), value); +} + /* See breakpoint.h. */ int @@ -2728,6 +2807,8 @@ insert_bp_location (struct bp_location *bl, if (!should_be_inserted (bl) || (bl->inserted && !bl->needs_update)) return 0; + breakpoint_debug_printf ("%s", breakpoint_location_address_str (bl).c_str ()); + /* Note we don't initialize bl->target_info, as that wipes out the breakpoint location's shadow_contents if the breakpoint is still inserted at that location. This in turn breaks @@ -3270,6 +3351,8 @@ remove_breakpoints_inf (inferior *inf) { int val; + breakpoint_debug_printf ("inf->num = %d", inf->num); + for (bp_location *bl : all_bp_locations ()) { if (bl->pspace != inf->pspace) @@ -3914,6 +3997,10 @@ detach_breakpoints (ptid_t ptid) static int remove_breakpoint_1 (struct bp_location *bl, enum remove_bp_reason reason) { + breakpoint_debug_printf ("%s due to %s", + breakpoint_location_address_str (bl).c_str (), + remove_bp_reason_str (reason)); + int val; /* BL is never in moribund_locations by our callers. */ @@ -7420,6 +7507,17 @@ bp_location::bp_location (breakpoint *owner) { } +/* See breakpoint.h. */ + +std::string +bp_location::to_string () const +{ + string_file stb; + ui_out_redirect_pop redir (current_uiout, &stb); + print_breakpoint_location (this->owner, this); + return stb.string (); +} + /* Decrement reference count. If the reference count reaches 0, destroy the bp_location. Sets *BLP to NULL. */ @@ -11153,6 +11251,9 @@ update_global_location_list (enum ugll_insert_mode insert_mode) /* Last breakpoint location program space that was marked for update. */ int last_pspace_num = -1; + breakpoint_debug_printf ("insert_mode = %s", + ugll_insert_mode_text (insert_mode)); + /* Used in the duplicates detection below. When iterating over all bp_locations, points to the first bp_location of a given address. Breakpoints and watchpoints of different types are never @@ -14895,6 +14996,15 @@ when execution stops."), &breakpoint_set_cmdlist, &breakpoint_show_cmdlist); + add_setshow_boolean_cmd ("breakpoint", class_maintenance, + &debug_breakpoint, _("\ +Set breakpoint location debugging."), _("\ +Show breakpoint location debugging."), _("\ +When on, breakpoint location specific debugging is enabled."), + NULL, + show_debug_breakpoint, + &setdebuglist, &showdebuglist); + add_setshow_enum_cmd ("condition-evaluation", class_breakpoint, condition_evaluation_enums, &condition_evaluation_mode_1, _("\ diff --git a/gdb/breakpoint.h b/gdb/breakpoint.h index da150585f73..f4896293bb7 100644 --- a/gdb/breakpoint.h +++ b/gdb/breakpoint.h @@ -509,6 +509,10 @@ public: /* The objfile the symbol or minimal symbol were found in. */ const struct objfile *objfile = NULL; + + /* Return a string representation of the bp_location. + This is only meant to be used in debug messages. */ + std::string to_string () const; }; /* A policy class for bp_location reference counting. */ diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo index bd11f0a4475..814cc6d714a 100644 --- a/gdb/doc/gdb.texinfo +++ b/gdb/doc/gdb.texinfo @@ -28366,6 +28366,14 @@ debugging info. Turn on or off debugging messages for built-in XML parsers. @item show debug xml Displays the current state of XML debugging messages. + +@item set debug breakpoints +@cindex breakpoint debugging info +Turns on or off display of @value{GDBN} debugging info for breakpoint insertion +and removal. The default is off. +@item show debug breakpoints +Displays the current state of displaying @value{GDBN} debugging info for +breakpoint insertion and removal. @end table @node Other Misc Settings -- 2.30.2