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This patch fixes a few problems with GDB's time handling. #1 - It avoids problems with gnulib's C++ namespace support On MinGW, the struct timeval that should be passed to gnulib's gettimeofday replacement is incompatible with libiberty's timeval_sub/timeval_add. That's because gnulib also replaces "struct timeval" with its own definition, while libiberty expects the system's. E.g., in code like this: gettimeofday (&prompt_ended, NULL); timeval_sub (&prompt_delta, &prompt_ended, &prompt_started); timeval_add (&prompt_for_continue_wait_time, &prompt_for_continue_wait_time, &prompt_delta); That's currently handled in gdb by not using gnulib's gettimeofday at all (see common/gdb_sys_time.h), but that #undef hack won't work with if/when we enable gnulib's C++ namespace support, because that mode adds compile time warnings for uses of ::gettimeofday, which are hard errors with -Werror. #2 - But there's an elephant in the room: gettimeofday is not monotonic... We're using it to: a) check how long functions take, for performance analysis b) compute when in the future to fire events in the event-loop c) print debug timestamps But that's exactly what gettimeofday is NOT meant for. Straight from the man page: ~~~ The time returned by gettimeofday() is affected by discontinuous jumps in the system time (e.g., if the system administrator manually changes the system time). If you need a monotonically increasing clock, see clock_gettime(2). ~~~ std::chrono (part of the C++11 standard library) has a monotonic clock exactly for such purposes (std::chrono::steady_clock). This commit switches to use that instead of gettimeofday, fixing all the issues mentioned above. gdb/ChangeLog: 2016-11-23 Pedro Alves <[email protected]> * Makefile.in (SFILES): Add common/run-time-clock.c. (HFILES_NO_SRCDIR): Add common/run-time-clock.h. (COMMON_OBS): Add run-time-clock.o. * common/run-time-clock.c, common/run-time-clock.h: New files. * defs.h (struct timeval, print_transfer_performance): Delete declarations. * event-loop.c (struct gdb_timer) <when>: Now a std::chrono::steady_clock::time_point. (create_timer): use std::chrono::steady_clock instead of gettimeofday. Use new instead of malloc. (delete_timer): Use delete instead of xfree. (duration_cast_timeval): New. (update_wait_timeout): Use std::chrono::steady_clock instead of gettimeofday. * maint.c: Include <chrono> instead of "gdb_sys_time.h", <time.h> and "timeval-utils.h". (scoped_command_stats::~scoped_command_stats) (scoped_command_stats::scoped_command_stats): Use std::chrono::steady_clock instead of gettimeofday. Use user_cpu_time_clock instead of get_run_time. * maint.h: Include "run-time-clock.h" and <chrono>. (scoped_command_stats): <m_start_cpu_time>: Now a user_cpu_time_clock::time_point. <m_start_wall_time>: Now a std::chrono::steady_clock::time_point. * mi/mi-main.c: Include "run-time-clock.h" and <chrono> instead of "gdb_sys_time.h" and <sys/resource.h>. (rusage): Delete. (mi_execute_command): Use new instead of XNEW. (mi_load_progress): Use std::chrono::steady_clock instead of gettimeofday. (timestamp): Rewrite in terms of std::chrono::steady_clock, user_cpu_time_clock and system_cpu_time_clock. (timeval_diff): Delete. (print_diff): Adjust to use std::chrono::steady_clock, user_cpu_time_clock and system_cpu_time_clock. * mi/mi-parse.h: Include "run-time-clock.h" and <chrono> instead of "gdb_sys_time.h". (struct mi_timestamp): Change fields types to std::chrono::steady_clock::time_point, user_cpu_time_clock::time and system_cpu_time_clock::time_point, instead of struct timeval. * symfile.c: Include <chrono> instead of <time.h> and "gdb_sys_time.h". (struct time_range): New. (generic_load): Use std::chrono::steady_clock instead of gettimeofday. (print_transfer_performance): Replace timeval parameters with a std::chrono::steady_clock::duration parameter. Adjust. * utils.c: Include <chrono> instead of "timeval-utils.h", "gdb_sys_time.h", and <time.h>. (prompt_for_continue_wait_time): Now a std::chrono::steady_clock::duration. (defaulted_query, prompt_for_continue): Use std::chrono::steady_clock instead of gettimeofday/timeval_sub/timeval_add. (reset_prompt_for_continue_wait_time): Use std::chrono::steady_clock::duration instead of struct timeval. (get_prompt_for_continue_wait_time): Return a std::chrono::steady_clock::duration instead of struct timeval. (vfprintf_unfiltered): Use std::chrono::steady_clock instead of gettimeofday. Use std::string. Use '.' instead of ':'. * utils.h: Include <chrono>. (get_prompt_for_continue_wait_time): Return a std::chrono::steady_clock::duration instead of struct timeval. gdb/gdbserver/ChangeLog: 2016-11-23 Pedro Alves <[email protected]> * debug.c: Include <chrono> instead of "gdb_sys_time.h". (debug_vprintf): Use std::chrono::steady_clock instead of gettimeofday. Use '.' instead of ':'. * tracepoint.c: Include <chrono> instead of "gdb_sys_time.h". (get_timestamp): Use std::chrono::steady_clock instead of gettimeofday.
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