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Diffstat (limited to 'gdb/infrun.c')
| -rw-r--r-- | gdb/infrun.c | 1690 |
1 files changed, 1690 insertions, 0 deletions
diff --git a/gdb/infrun.c b/gdb/infrun.c new file mode 100644 index 0000000..1cca592 --- /dev/null +++ b/gdb/infrun.c @@ -0,0 +1,1690 @@ +/* Start (run) and stop the inferior process, for GDB. + Copyright (C) 1986, 1987, 1988, 1989, 1991 Free Software Foundation, Inc. + +This file is part of GDB. + +GDB is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 1, or (at your option) +any later version. + +GDB is distributed in the hope that it will be useful, +but WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +GNU General Public License for more details. + +You should have received a copy of the GNU General Public License +along with GDB; see the file COPYING. If not, write to +the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */ + +/* Notes on the algorithm used in wait_for_inferior to determine if we + just did a subroutine call when stepping. We have the following + information at that point: + + Current and previous (just before this step) pc. + Current and previous sp. + Current and previous start of current function. + + If the start's of the functions don't match, then + + a) We did a subroutine call. + + In this case, the pc will be at the beginning of a function. + + b) We did a subroutine return. + + Otherwise. + + c) We did a longjmp. + + If we did a longjump, we were doing "nexti", since a next would + have attempted to skip over the assembly language routine in which + the longjmp is coded and would have simply been the equivalent of a + continue. I consider this ok behaivior. We'd like one of two + things to happen if we are doing a nexti through the longjmp() + routine: 1) It behaves as a stepi, or 2) It acts like a continue as + above. Given that this is a special case, and that anybody who + thinks that the concept of sub calls is meaningful in the context + of a longjmp, I'll take either one. Let's see what happens. + + Acts like a subroutine return. I can handle that with no problem + at all. + + -->So: If the current and previous beginnings of the current + function don't match, *and* the pc is at the start of a function, + we've done a subroutine call. If the pc is not at the start of a + function, we *didn't* do a subroutine call. + + -->If the beginnings of the current and previous function do match, + either: + + a) We just did a recursive call. + + In this case, we would be at the very beginning of a + function and 1) it will have a prologue (don't jump to + before prologue, or 2) (we assume here that it doesn't have + a prologue) there will have been a change in the stack + pointer over the last instruction. (Ie. it's got to put + the saved pc somewhere. The stack is the usual place. In + a recursive call a register is only an option if there's a + prologue to do something with it. This is even true on + register window machines; the prologue sets up the new + window. It might not be true on a register window machine + where the call instruction moved the register window + itself. Hmmm. One would hope that the stack pointer would + also change. If it doesn't, somebody send me a note, and + I'll work out a more general theory. + bug-gdb@prep.ai.mit.edu). This is true (albeit slipperly + so) on all machines I'm aware of: + + m68k: Call changes stack pointer. Regular jumps don't. + + sparc: Recursive calls must have frames and therefor, + prologues. + + vax: All calls have frames and hence change the + stack pointer. + + b) We did a return from a recursive call. I don't see that we + have either the ability or the need to distinguish this + from an ordinary jump. The stack frame will be printed + when and if the frame pointer changes; if we are in a + function without a frame pointer, it's the users own + lookout. + + c) We did a jump within a function. We assume that this is + true if we didn't do a recursive call. + + d) We are in no-man's land ("I see no symbols here"). We + don't worry about this; it will make calls look like simple + jumps (and the stack frames will be printed when the frame + pointer moves), which is a reasonably non-violent response. + +#if 0 + We skip this; it causes more problems than it's worth. +#ifdef SUN4_COMPILER_FEATURE + We do a special ifdef for the sun 4, forcing it to single step + into calls which don't have prologues. This means that we can't + nexti over leaf nodes, we can probably next over them (since they + won't have debugging symbols, usually), and we can next out of + functions returning structures (with a "call .stret4" at the end). +#endif +#endif +*/ + + + + + +#include <stdio.h> +#include <string.h> +#include "defs.h" +#include "param.h" +#include "symtab.h" +#include "frame.h" +#include "inferior.h" +#include "breakpoint.h" +#include "wait.h" +#include "gdbcore.h" +#include "signame.h" +#include "command.h" +#include "terminal.h" /* For #ifdef TIOCGPGRP and new_tty */ +#include "target.h" + +#include <signal.h> + +/* unistd.h is needed to #define X_OK */ +#ifdef USG +#include <unistd.h> +#else +#include <sys/file.h> +#endif + +#ifdef SET_STACK_LIMIT_HUGE +extern int original_stack_limit; +#endif /* SET_STACK_LIMIT_HUGE */ + +/* Required by <sys/user.h>. */ +#include <sys/types.h> +/* Required by <sys/user.h>, at least on system V. */ +#include <sys/dir.h> +/* Needed by IN_SIGTRAMP on some machines (e.g. vax). */ +#include <sys/param.h> +/* Needed by IN_SIGTRAMP on some machines (e.g. vax). */ +#include <sys/user.h> + +extern char *getenv (); + +extern struct target_ops child_ops; /* In inftarg.c */ + +/* Copy of inferior_io_terminal when inferior was last started. */ + +extern char *inferior_thisrun_terminal; + + +/* Sigtramp is a routine that the kernel calls (which then calls the + signal handler). On most machines it is a library routine that + is linked into the executable. + + This macro, given a program counter value and the name of the + function in which that PC resides (which can be null if the + name is not known), returns nonzero if the PC and name show + that we are in sigtramp. + + On most machines just see if the name is sigtramp (and if we have + no name, assume we are not in sigtramp). */ +#if !defined (IN_SIGTRAMP) +#define IN_SIGTRAMP(pc, name) \ + name && !strcmp ("_sigtramp", name) +#endif + +/* Tables of how to react to signals; the user sets them. */ + +static char signal_stop[NSIG]; +static char signal_print[NSIG]; +static char signal_program[NSIG]; + +/* Nonzero if breakpoints are now inserted in the inferior. */ +/* Nonstatic for initialization during xxx_create_inferior. FIXME. */ + +/*static*/ int breakpoints_inserted; + +/* Function inferior was in as of last step command. */ + +static struct symbol *step_start_function; + +/* Nonzero => address for special breakpoint for resuming stepping. */ + +static CORE_ADDR step_resume_break_address; + +/* Pointer to orig contents of the byte where the special breakpoint is. */ + +static char step_resume_break_shadow[BREAKPOINT_MAX]; + +/* Nonzero means the special breakpoint is a duplicate + so it has not itself been inserted. */ + +static int step_resume_break_duplicate; + +/* Nonzero if we are expecting a trace trap and should proceed from it. */ + +static int trap_expected; + +/* Nonzero if the next time we try to continue the inferior, it will + step one instruction and generate a spurious trace trap. + This is used to compensate for a bug in HP-UX. */ + +static int trap_expected_after_continue; + +/* Nonzero means expecting a trace trap + and should stop the inferior and return silently when it happens. */ + +int stop_after_trap; + +/* Nonzero means expecting a trap and caller will handle it themselves. + It is used after attach, due to attaching to a process; + when running in the shell before the child program has been exec'd; + and when running some kinds of remote stuff (FIXME?). */ + +int stop_soon_quietly; + +/* Nonzero if pc has been changed by the debugger + since the inferior stopped. */ + +int pc_changed; + +/* Nonzero if proceed is being used for a "finish" command or a similar + situation when stop_registers should be saved. */ + +int proceed_to_finish; + +/* Save register contents here when about to pop a stack dummy frame, + if-and-only-if proceed_to_finish is set. + Thus this contains the return value from the called function (assuming + values are returned in a register). */ + +char stop_registers[REGISTER_BYTES]; + +/* Nonzero if program stopped due to error trying to insert breakpoints. */ + +static int breakpoints_failed; + +/* Nonzero after stop if current stack frame should be printed. */ + +static int stop_print_frame; + +#ifdef NO_SINGLE_STEP +extern int one_stepped; /* From machine dependent code */ +extern void single_step (); /* Same. */ +#endif /* NO_SINGLE_STEP */ + +static void insert_step_breakpoint (); +static void remove_step_breakpoint (); +/*static*/ void wait_for_inferior (); +void init_wait_for_inferior (); +void normal_stop (); + + +/* Clear out all variables saying what to do when inferior is continued. + First do this, then set the ones you want, then call `proceed'. */ + +void +clear_proceed_status () +{ + trap_expected = 0; + step_range_start = 0; + step_range_end = 0; + step_frame_address = 0; + step_over_calls = -1; + step_resume_break_address = 0; + stop_after_trap = 0; + stop_soon_quietly = 0; + proceed_to_finish = 0; + breakpoint_proceeded = 1; /* We're about to proceed... */ + + /* Discard any remaining commands or status from previous stop. */ + bpstat_clear (&stop_bpstat); +} + +/* Basic routine for continuing the program in various fashions. + + ADDR is the address to resume at, or -1 for resume where stopped. + SIGGNAL is the signal to give it, or 0 for none, + or -1 for act according to how it stopped. + STEP is nonzero if should trap after one instruction. + -1 means return after that and print nothing. + You should probably set various step_... variables + before calling here, if you are stepping. + + You should call clear_proceed_status before calling proceed. */ + +void +proceed (addr, siggnal, step) + CORE_ADDR addr; + int siggnal; + int step; +{ + int oneproc = 0; + + if (step > 0) + step_start_function = find_pc_function (read_pc ()); + if (step < 0) + stop_after_trap = 1; + + if (addr == -1) + { + /* If there is a breakpoint at the address we will resume at, + step one instruction before inserting breakpoints + so that we do not stop right away. */ + + if (!pc_changed && breakpoint_here_p (read_pc ())) + oneproc = 1; + } + else + { + write_register (PC_REGNUM, addr); +#ifdef NPC_REGNUM + write_register (NPC_REGNUM, addr + 4); +#ifdef NNPC_REGNUM + write_register (NNPC_REGNUM, addr + 8); +#endif +#endif + } + + if (trap_expected_after_continue) + { + /* If (step == 0), a trap will be automatically generated after + the first instruction is executed. Force step one + instruction to clear this condition. This should not occur + if step is nonzero, but it is harmless in that case. */ + oneproc = 1; + trap_expected_after_continue = 0; + } + + if (oneproc) + /* We will get a trace trap after one instruction. + Continue it automatically and insert breakpoints then. */ + trap_expected = 1; + else + { + int temp = insert_breakpoints (); + if (temp) + { + print_sys_errmsg ("ptrace", temp); + error ("Cannot insert breakpoints.\n\ +The same program may be running in another process."); + } + breakpoints_inserted = 1; + } + + /* Install inferior's terminal modes. */ + target_terminal_inferior (); + + if (siggnal >= 0) + stop_signal = siggnal; + /* If this signal should not be seen by program, + give it zero. Used for debugging signals. */ + else if (stop_signal < NSIG && !signal_program[stop_signal]) + stop_signal= 0; + + /* Handle any optimized stores to the inferior NOW... */ +#ifdef DO_DEFERRED_STORES + DO_DEFERRED_STORES; +#endif + + /* Resume inferior. */ + target_resume (oneproc || step || bpstat_should_step (), stop_signal); + + /* Wait for it to stop (if not standalone) + and in any case decode why it stopped, and act accordingly. */ + + wait_for_inferior (); + normal_stop (); +} + +#if 0 +/* This might be useful (not sure), but isn't currently used. See also + write_pc(). */ +/* Writing the inferior pc as a register calls this function + to inform infrun that the pc has been set in the debugger. */ + +void +writing_pc (val) + CORE_ADDR val; +{ + stop_pc = val; + pc_changed = 1; +} +#endif + +/* Record the pc and sp of the program the last time it stopped. + These are just used internally by wait_for_inferior, but need + to be preserved over calls to it and cleared when the inferior + is started. */ +static CORE_ADDR prev_pc; +static CORE_ADDR prev_sp; +static CORE_ADDR prev_func_start; +static char *prev_func_name; + +/* Start an inferior Unix child process and sets inferior_pid to its pid. + EXEC_FILE is the file to run. + ALLARGS is a string containing the arguments to the program. + ENV is the environment vector to pass. Errors reported with error(). */ + +#ifndef SHELL_FILE +#define SHELL_FILE "/bin/sh" +#endif + +void +child_create_inferior (exec_file, allargs, env) + char *exec_file; + char *allargs; + char **env; +{ + int pid; + char *shell_command; + extern int sys_nerr; + extern char *sys_errlist[]; + char *shell_file; + static char default_shell_file[] = SHELL_FILE; + int len; + int pending_execs; + /* Set debug_fork then attach to the child while it sleeps, to debug. */ + static int debug_fork = 0; + /* This is set to the result of setpgrp, which if vforked, will be visible + to you in the parent process. It's only used by humans for debugging. */ + static int debug_setpgrp = 657473; + + /* The user might want tilde-expansion, and in general probably wants + the program to behave the same way as if run from + his/her favorite shell. So we let the shell run it for us. + FIXME, this should probably search the local environment (as + modified by the setenv command), not the env gdb inherited. */ + shell_file = getenv ("SHELL"); + if (shell_file == NULL) + shell_file = default_shell_file; + + len = 5 + strlen (exec_file) + 1 + strlen (allargs) + 1 + /*slop*/ 10; + /* If desired, concat something onto the front of ALLARGS. + SHELL_COMMAND is the result. */ +#ifdef SHELL_COMMAND_CONCAT + shell_command = (char *) alloca (strlen (SHELL_COMMAND_CONCAT) + len); + strcpy (shell_command, SHELL_COMMAND_CONCAT); +#else + shell_command = (char *) alloca (len); + shell_command[0] = '\0'; +#endif + strcat (shell_command, "exec "); + strcat (shell_command, exec_file); + strcat (shell_command, " "); + strcat (shell_command, allargs); + + /* exec is said to fail if the executable is open. */ + close_exec_file (); + +#if defined(USG) && !defined(HAVE_VFORK) + pid = fork (); +#else + if (debug_fork) + pid = fork (); + else + pid = vfork (); +#endif + + if (pid < 0) + perror_with_name ("vfork"); + + if (pid == 0) + { + if (debug_fork) + sleep (debug_fork); + +#ifdef TIOCGPGRP + /* Run inferior in a separate process group. */ + debug_setpgrp = setpgrp (getpid (), getpid ()); + if (0 != debug_setpgrp) + perror("setpgrp failed in child"); +#endif /* TIOCGPGRP */ + +#ifdef SET_STACK_LIMIT_HUGE + /* Reset the stack limit back to what it was. */ + { + struct rlimit rlim; + + getrlimit (RLIMIT_STACK, &rlim); + rlim.rlim_cur = original_stack_limit; + setrlimit (RLIMIT_STACK, &rlim); + } +#endif /* SET_STACK_LIMIT_HUGE */ + + /* Tell the terminal handling subsystem what tty we plan to run on; + it will now switch to that one if non-null. */ + + new_tty (inferior_io_terminal); + + /* Changing the signal handlers for the inferior after + a vfork can also change them for the superior, so we don't mess + with signals here. See comments in + initialize_signals for how we get the right signal handlers + for the inferior. */ + + call_ptrace (0, 0, 0, 0); /* "Trace me, Dr. Memory!" */ + execle (shell_file, shell_file, "-c", shell_command, (char *)0, env); + + fprintf (stderr, "Cannot exec %s: %s.\n", shell_file, + errno < sys_nerr ? sys_errlist[errno] : "unknown error"); + fflush (stderr); + _exit (0177); + } + + /* Now that we have a child process, make it our target. */ + push_target (&child_ops); + +#ifdef CREATE_INFERIOR_HOOK + CREATE_INFERIOR_HOOK (pid); +#endif + +/* The process was started by the fork that created it, + but it will have stopped one instruction after execing the shell. + Here we must get it up to actual execution of the real program. */ + + inferior_pid = pid; /* Needed for wait_for_inferior stuff below */ + + clear_proceed_status (); + +#if defined (START_INFERIOR_HOOK) + START_INFERIOR_HOOK (); +#endif + + /* We will get a trace trap after one instruction. + Continue it automatically. Eventually (after shell does an exec) + it will get another trace trap. Then insert breakpoints and continue. */ + +#ifdef START_INFERIOR_TRAPS_EXPECTED + pending_execs = START_INFERIOR_TRAPS_EXPECTED; +#else + pending_execs = 2; +#endif + + init_wait_for_inferior (); + + /* Set up the "saved terminal modes" of the inferior + based on what modes we are starting it with. */ + target_terminal_init (); + + /* Install inferior's terminal modes. */ + target_terminal_inferior (); + + while (1) + { + stop_soon_quietly = 1; /* Make wait_for_inferior be quiet */ + wait_for_inferior (); + if (stop_signal != SIGTRAP) + { + /* Let shell child handle its own signals in its own way */ + /* FIXME, what if child has exit()ed? Must exit loop somehow */ + target_resume (0, stop_signal); + } + else + { + /* We handle SIGTRAP, however; it means child did an exec. */ + if (0 == --pending_execs) + break; + target_resume (0, 0); /* Just make it go on */ + } + } + stop_soon_quietly = 0; + + /* Should this perhaps just be a "proceed" call? FIXME */ + insert_step_breakpoint (); + breakpoints_failed = insert_breakpoints (); + if (!breakpoints_failed) + { + breakpoints_inserted = 1; + target_terminal_inferior(); + /* Start the child program going on its first instruction, single- + stepping if we need to. */ + target_resume (bpstat_should_step (), 0); + wait_for_inferior (); + normal_stop (); + } +} + +/* Start remote-debugging of a machine over a serial link. */ + +void +start_remote () +{ + init_wait_for_inferior (); + clear_proceed_status (); + stop_soon_quietly = 1; + trap_expected = 0; +} + +/* Initialize static vars when a new inferior begins. */ + +void +init_wait_for_inferior () +{ + /* These are meaningless until the first time through wait_for_inferior. */ + prev_pc = 0; + prev_sp = 0; + prev_func_start = 0; + prev_func_name = NULL; + + trap_expected_after_continue = 0; + breakpoints_inserted = 0; + mark_breakpoints_out (); + stop_signal = 0; /* Don't confuse first call to proceed(). */ +} + + +/* Attach to process PID, then initialize for debugging it + and wait for the trace-trap that results from attaching. */ + +void +child_attach (args, from_tty) + char *args; + int from_tty; +{ + char *exec_file; + int pid; + + dont_repeat(); + + if (!args) + error_no_arg ("process-id to attach"); + +#ifndef ATTACH_DETACH + error ("Can't attach to a process on this machine."); +#else + pid = atoi (args); + + if (target_has_execution) + { + if (query ("A program is being debugged already. Kill it? ")) + target_kill ((char *)0, from_tty); + else + error ("Inferior not killed."); + } + + exec_file = (char *) get_exec_file (1); + + if (from_tty) + { + printf ("Attaching program: %s pid %d\n", + exec_file, pid); + fflush (stdout); + } + + attach (pid); + inferior_pid = pid; + push_target (&child_ops); + + mark_breakpoints_out (); + target_terminal_init (); + clear_proceed_status (); + stop_soon_quietly = 1; + /*proceed (-1, 0, -2);*/ + target_terminal_inferior (); + wait_for_inferior (); + normal_stop (); +#endif /* ATTACH_DETACH */ +} + +/* Wait for control to return from inferior to debugger. + If inferior gets a signal, we may decide to start it up again + instead of returning. That is why there is a loop in this function. + When this function actually returns it means the inferior + should be left stopped and GDB should read more commands. */ + +void +wait_for_inferior () +{ + WAITTYPE w; + int another_trap; + int random_signal; + CORE_ADDR stop_sp; + CORE_ADDR stop_func_start; + char *stop_func_name; + CORE_ADDR prologue_pc; + int stop_step_resume_break; + struct symtab_and_line sal; + int remove_breakpoints_on_following_step = 0; + +#if 0 + /* This no longer works now that read_register is lazy; + it might try to ptrace when the process is not stopped. */ + prev_pc = read_pc (); + (void) find_pc_partial_function (prev_pc, &prev_func_name, + &prev_func_start); + prev_func_start += FUNCTION_START_OFFSET; + prev_sp = read_register (SP_REGNUM); +#endif /* 0 */ + + while (1) + { + /* Clean up saved state that will become invalid. */ + pc_changed = 0; + flush_cached_frames (); + registers_changed (); + + target_wait (&w); + + /* See if the process still exists; clean up if it doesn't. */ + if (WIFEXITED (w)) + { + target_terminal_ours (); /* Must do this before mourn anyway */ + if (WEXITSTATUS (w)) + printf ("\nProgram exited with code 0%o.\n", + (unsigned int)WEXITSTATUS (w)); + else + if (!batch_mode()) + printf ("\nProgram exited normally.\n"); + fflush (stdout); + target_mourn_inferior (); +#ifdef NO_SINGLE_STEP + one_stepped = 0; +#endif + stop_print_frame = 0; + break; + } + else if (!WIFSTOPPED (w)) + { + stop_print_frame = 0; + stop_signal = WTERMSIG (w); + target_terminal_ours (); /* Must do this before mourn anyway */ + target_kill ((char *)0, 0); /* kill mourns as well */ +#ifdef PRINT_RANDOM_SIGNAL + printf ("\nProgram terminated: "); + PRINT_RANDOM_SIGNAL (stop_signal); +#else + printf ("\nProgram terminated with signal %d, %s\n", + stop_signal, + stop_signal < NSIG + ? sys_siglist[stop_signal] + : "(undocumented)"); +#endif + printf ("The inferior process no longer exists.\n"); + fflush (stdout); +#ifdef NO_SINGLE_STEP + one_stepped = 0; +#endif + break; + } + +#ifdef NO_SINGLE_STEP + if (one_stepped) + single_step (0); /* This actually cleans up the ss */ +#endif /* NO_SINGLE_STEP */ + + stop_pc = read_pc (); + set_current_frame ( create_new_frame (read_register (FP_REGNUM), + read_pc ())); + + stop_frame_address = FRAME_FP (get_current_frame ()); + stop_sp = read_register (SP_REGNUM); + stop_func_start = 0; + stop_func_name = 0; + /* Don't care about return value; stop_func_start and stop_func_name + will both be 0 if it doesn't work. */ + (void) find_pc_partial_function (stop_pc, &stop_func_name, + &stop_func_start); + stop_func_start += FUNCTION_START_OFFSET; + another_trap = 0; + bpstat_clear (&stop_bpstat); + stop_step = 0; + stop_stack_dummy = 0; + stop_print_frame = 1; + stop_step_resume_break = 0; + random_signal = 0; + stopped_by_random_signal = 0; + breakpoints_failed = 0; + + /* Look at the cause of the stop, and decide what to do. + The alternatives are: + 1) break; to really stop and return to the debugger, + 2) drop through to start up again + (set another_trap to 1 to single step once) + 3) set random_signal to 1, and the decision between 1 and 2 + will be made according to the signal handling tables. */ + + stop_signal = WSTOPSIG (w); + + /* First, distinguish signals caused by the debugger from signals + that have to do with the program's own actions. + Note that breakpoint insns may cause SIGTRAP or SIGILL + or SIGEMT, depending on the operating system version. + Here we detect when a SIGILL or SIGEMT is really a breakpoint + and change it to SIGTRAP. */ + + if (stop_signal == SIGTRAP + || (breakpoints_inserted && + (stop_signal == SIGILL + || stop_signal == SIGEMT)) + || stop_soon_quietly) + { + if (stop_signal == SIGTRAP && stop_after_trap) + { + stop_print_frame = 0; + break; + } + if (stop_soon_quietly) + break; + + /* Don't even think about breakpoints + if just proceeded over a breakpoint. + + However, if we are trying to proceed over a breakpoint + and end up in sigtramp, then step_resume_break_address + will be set and we should check whether we've hit the + step breakpoint. */ + if (stop_signal == SIGTRAP && trap_expected + && step_resume_break_address == NULL) + bpstat_clear (&stop_bpstat); + else + { + /* See if there is a breakpoint at the current PC. */ +#if DECR_PC_AFTER_BREAK + /* Notice the case of stepping through a jump + that leads just after a breakpoint. + Don't confuse that with hitting the breakpoint. + What we check for is that 1) stepping is going on + and 2) the pc before the last insn does not match + the address of the breakpoint before the current pc. */ + if (!(prev_pc != stop_pc - DECR_PC_AFTER_BREAK + && step_range_end && !step_resume_break_address)) +#endif /* DECR_PC_AFTER_BREAK not zero */ + { + /* See if we stopped at the special breakpoint for + stepping over a subroutine call. If both are zero, + this wasn't the reason for the stop. */ + if (stop_pc - DECR_PC_AFTER_BREAK + == step_resume_break_address + && step_resume_break_address) + { + stop_step_resume_break = 1; + if (DECR_PC_AFTER_BREAK) + { + stop_pc -= DECR_PC_AFTER_BREAK; + write_register (PC_REGNUM, stop_pc); + pc_changed = 0; + } + } + else + { + stop_bpstat = + bpstat_stop_status (&stop_pc, stop_frame_address); + /* Following in case break condition called a + function. */ + stop_print_frame = 1; + } + } + } + + if (stop_signal == SIGTRAP) + random_signal + = !(bpstat_explains_signal (stop_bpstat) + || trap_expected + || stop_step_resume_break + || PC_IN_CALL_DUMMY (stop_pc, stop_sp, stop_frame_address) + || (step_range_end && !step_resume_break_address)); + else + { + random_signal + = !(bpstat_explains_signal (stop_bpstat) + || stop_step_resume_break + /* End of a stack dummy. Some systems (e.g. Sony + news) give another signal besides SIGTRAP, + so check here as well as above. */ + || (stop_sp INNER_THAN stop_pc + && stop_pc INNER_THAN stop_frame_address) + ); + if (!random_signal) + stop_signal = SIGTRAP; + } + } + else + random_signal = 1; + + /* For the program's own signals, act according to + the signal handling tables. */ + + if (random_signal) + { + /* Signal not for debugging purposes. */ + int printed = 0; + + stopped_by_random_signal = 1; + + if (stop_signal >= NSIG + || signal_print[stop_signal]) + { + printed = 1; + target_terminal_ours_for_output (); +#ifdef PRINT_RANDOM_SIGNAL + PRINT_RANDOM_SIGNAL (stop_signal); +#else + printf ("\nProgram received signal %d, %s\n", + stop_signal, + stop_signal < NSIG + ? sys_siglist[stop_signal] + : "(undocumented)"); +#endif /* PRINT_RANDOM_SIGNAL */ + fflush (stdout); + } + if (stop_signal >= NSIG + || signal_stop[stop_signal]) + break; + /* If not going to stop, give terminal back + if we took it away. */ + else if (printed) + target_terminal_inferior (); + } + + /* Handle cases caused by hitting a breakpoint. */ + + if (!random_signal + && (bpstat_explains_signal (stop_bpstat) || stop_step_resume_break)) + { + /* Does a breakpoint want us to stop? */ + if (bpstat_stop (stop_bpstat)) + { + stop_print_frame = bpstat_should_print (stop_bpstat); + break; + } + /* But if we have hit the step-resumption breakpoint, + remove it. It has done its job getting us here. + The sp test is to make sure that we don't get hung + up in recursive calls in functions without frame + pointers. If the stack pointer isn't outside of + where the breakpoint was set (within a routine to be + stepped over), we're in the middle of a recursive + call. Not true for reg window machines (sparc) + because the must change frames to call things and + the stack pointer doesn't have to change if it + the bp was set in a routine without a frame (pc can + be stored in some other window). + + The removal of the sp test is to allow calls to + alloca. Nasty things were happening. Oh, well, + gdb can only handle one level deep of lack of + frame pointer. */ + if (stop_step_resume_break + && (step_frame_address == 0 + || (stop_frame_address == step_frame_address))) + { + remove_step_breakpoint (); + step_resume_break_address = 0; + + /* If were waiting for a trap, hitting the step_resume_break + doesn't count as getting it. */ + if (trap_expected) + another_trap = 1; + } + /* Otherwise, must remove breakpoints and single-step + to get us past the one we hit. */ + else + { + remove_breakpoints (); + remove_step_breakpoint (); + breakpoints_inserted = 0; + another_trap = 1; + } + + /* We come here if we hit a breakpoint but should not + stop for it. Possibly we also were stepping + and should stop for that. So fall through and + test for stepping. But, if not stepping, + do not stop. */ + } + + /* If this is the breakpoint at the end of a stack dummy, + just stop silently. */ + if (PC_IN_CALL_DUMMY (stop_pc, stop_sp, stop_frame_address)) + { + stop_print_frame = 0; + stop_stack_dummy = 1; +#ifdef HP_OS_BUG + trap_expected_after_continue = 1; +#endif + break; + } + + if (step_resume_break_address) + /* Having a step-resume breakpoint overrides anything + else having to do with stepping commands until + that breakpoint is reached. */ + ; + /* If stepping through a line, keep going if still within it. */ + else if (!random_signal + && step_range_end + && stop_pc >= step_range_start + && stop_pc < step_range_end + /* The step range might include the start of the + function, so if we are at the start of the + step range and either the stack or frame pointers + just changed, we've stepped outside */ + && !(stop_pc == step_range_start + && stop_frame_address + && (stop_sp INNER_THAN prev_sp + || stop_frame_address != step_frame_address))) + { +#if 0 + /* When "next"ing through a function, + This causes an extra stop at the end. + Is there any reason for this? + It's confusing to the user. */ + /* Don't step through the return from a function + unless that is the first instruction stepped through. */ + if (ABOUT_TO_RETURN (stop_pc)) + { + stop_step = 1; + break; + } +#endif + } + + /* We stepped out of the stepping range. See if that was due + to a subroutine call that we should proceed to the end of. */ + else if (!random_signal && step_range_end) + { + if (stop_func_start) + { + prologue_pc = stop_func_start; + SKIP_PROLOGUE (prologue_pc); + } + + /* Did we just take a signal? */ + if (IN_SIGTRAMP (stop_pc, stop_func_name) + && !IN_SIGTRAMP (prev_pc, prev_func_name)) + { + /* This code is needed at least in the following case: + The user types "next" and then a signal arrives (before + the "next" is done). */ + /* We've just taken a signal; go until we are back to + the point where we took it and one more. */ + step_resume_break_address = prev_pc; + step_resume_break_duplicate = + breakpoint_here_p (step_resume_break_address); + if (breakpoints_inserted) + insert_step_breakpoint (); + /* Make sure that the stepping range gets us past + that instruction. */ + if (step_range_end == 1) + step_range_end = (step_range_start = prev_pc) + 1; + remove_breakpoints_on_following_step = 1; + } + + /* ==> See comments at top of file on this algorithm. <==*/ + + else if (stop_pc == stop_func_start + && (stop_func_start != prev_func_start + || prologue_pc != stop_func_start + || stop_sp != prev_sp)) + { + /* It's a subroutine call */ + if (step_over_calls > 0 + || (step_over_calls && find_pc_function (stop_pc) == 0)) + { + /* A subroutine call has happened. */ + /* Set a special breakpoint after the return */ + step_resume_break_address = + ADDR_BITS_REMOVE + (SAVED_PC_AFTER_CALL (get_current_frame ())); + step_resume_break_duplicate + = breakpoint_here_p (step_resume_break_address); + if (breakpoints_inserted) + insert_step_breakpoint (); + } + /* Subroutine call with source code we should not step over. + Do step to the first line of code in it. */ + else if (step_over_calls) + { + SKIP_PROLOGUE (stop_func_start); + sal = find_pc_line (stop_func_start, 0); + /* Use the step_resume_break to step until + the end of the prologue, even if that involves jumps + (as it seems to on the vax under 4.2). */ + /* If the prologue ends in the middle of a source line, + continue to the end of that source line. + Otherwise, just go to end of prologue. */ +#ifdef PROLOGUE_FIRSTLINE_OVERLAP + /* no, don't either. It skips any code that's + legitimately on the first line. */ +#else + if (sal.end && sal.pc != stop_func_start) + stop_func_start = sal.end; +#endif + + if (stop_func_start == stop_pc) + { + /* We are already there: stop now. */ + stop_step = 1; + break; + } + else + /* Put the step-breakpoint there and go until there. */ + { + step_resume_break_address = stop_func_start; + + step_resume_break_duplicate + = breakpoint_here_p (step_resume_break_address); + if (breakpoints_inserted) + insert_step_breakpoint (); + /* Do not specify what the fp should be when we stop + since on some machines the prologue + is where the new fp value is established. */ + step_frame_address = 0; + /* And make sure stepping stops right away then. */ + step_range_end = step_range_start; + } + } + else + { + /* We get here only if step_over_calls is 0 and we + just stepped into a subroutine. I presume + that step_over_calls is only 0 when we're + supposed to be stepping at the assembly + language level.*/ + stop_step = 1; + break; + } + } + /* No subroutince call; stop now. */ + else + { + stop_step = 1; + break; + } + } + + else if (trap_expected + && IN_SIGTRAMP (stop_pc, stop_func_name) + && !IN_SIGTRAMP (prev_pc, prev_func_name)) + { + /* What has happened here is that we have just stepped the inferior + with a signal (because it is a signal which shouldn't make + us stop), thus stepping into sigtramp. + + So we need to set a step_resume_break_address breakpoint + and continue until we hit it, and then step. */ + step_resume_break_address = prev_pc; + /* Always 1, I think, but it's probably easier to have + the step_resume_break as usual rather than trying to + re-use the breakpoint which is already there. */ + step_resume_break_duplicate = + breakpoint_here_p (step_resume_break_address); + if (breakpoints_inserted) + insert_step_breakpoint (); + remove_breakpoints_on_following_step = 1; + another_trap = 1; + } + + /* Save the pc before execution, to compare with pc after stop. */ + prev_pc = read_pc (); /* Might have been DECR_AFTER_BREAK */ + prev_func_start = stop_func_start; /* Ok, since if DECR_PC_AFTER + BREAK is defined, the + original pc would not have + been at the start of a + function. */ + prev_func_name = stop_func_name; + prev_sp = stop_sp; + + /* If we did not do break;, it means we should keep + running the inferior and not return to debugger. */ + + if (trap_expected && stop_signal != SIGTRAP) + { + /* We took a signal (which we are supposed to pass through to + the inferior, else we'd have done a break above) and we + haven't yet gotten our trap. Simply continue. */ + target_resume ((step_range_end && !step_resume_break_address) + || (trap_expected && !step_resume_break_address) + || bpstat_should_step (), + stop_signal); + } + else + { + /* Either the trap was not expected, but we are continuing + anyway (the user asked that this signal be passed to the + child) + -- or -- + The signal was SIGTRAP, e.g. it was our signal, but we + decided we should resume from it. + + We're going to run this baby now! + + Insert breakpoints now, unless we are trying + to one-proceed past a breakpoint. */ + /* If we've just finished a special step resume and we don't + want to hit a breakpoint, pull em out. */ + if (!step_resume_break_address && + remove_breakpoints_on_following_step) + { + remove_breakpoints_on_following_step = 0; + remove_breakpoints (); + breakpoints_inserted = 0; + } + else if (!breakpoints_inserted && + (step_resume_break_address != NULL || !another_trap)) + { + insert_step_breakpoint (); + breakpoints_failed = insert_breakpoints (); + if (breakpoints_failed) + break; + breakpoints_inserted = 1; + } + + trap_expected = another_trap; + + if (stop_signal == SIGTRAP) + stop_signal = 0; + +#ifdef SHIFT_INST_REGS + /* I'm not sure when this following segment applies. I do know, now, + that we shouldn't rewrite the regs when we were stopped by a + random signal from the inferior process. */ + + if (!stop_breakpoint && (stop_signal != SIGCLD) + && !stopped_by_random_signal) + { + CORE_ADDR pc_contents = read_register (PC_REGNUM); + CORE_ADDR npc_contents = read_register (NPC_REGNUM); + if (pc_contents != npc_contents) + { + write_register (NNPC_REGNUM, npc_contents); + write_register (NPC_REGNUM, pc_contents); + } + } +#endif /* SHIFT_INST_REGS */ + + target_resume ((step_range_end && !step_resume_break_address) + || (trap_expected && !step_resume_break_address) + || bpstat_should_step (), + stop_signal); + } + } + if (target_has_execution) + { + /* Assuming the inferior still exists, set these up for next + time, just like we did above if we didn't break out of the + loop. */ + prev_pc = read_pc (); + prev_func_start = stop_func_start; + prev_func_name = stop_func_name; + prev_sp = stop_sp; + } +} + +/* Here to return control to GDB when the inferior stops for real. + Print appropriate messages, remove breakpoints, give terminal our modes. + + STOP_PRINT_FRAME nonzero means print the executing frame + (pc, function, args, file, line number and line text). + BREAKPOINTS_FAILED nonzero means stop was due to error + attempting to insert breakpoints. */ + +void +normal_stop () +{ + /* Make sure that the current_frame's pc is correct. This + is a correction for setting up the frame info before doing + DECR_PC_AFTER_BREAK */ + if (target_has_execution) + (get_current_frame ())->pc = read_pc (); + + if (breakpoints_failed) + { + target_terminal_ours_for_output (); + print_sys_errmsg ("ptrace", breakpoints_failed); + printf ("Stopped; cannot insert breakpoints.\n\ +The same program may be running in another process.\n"); + } + + if (target_has_execution) + remove_step_breakpoint (); + + if (target_has_execution && breakpoints_inserted) + if (remove_breakpoints ()) + { + target_terminal_ours_for_output (); + printf ("Cannot remove breakpoints because program is no longer writable.\n\ +It might be running in another process.\n\ +Further execution is probably impossible.\n"); + } + + breakpoints_inserted = 0; + + /* Delete the breakpoint we stopped at, if it wants to be deleted. + Delete any breakpoint that is to be deleted at the next stop. */ + + breakpoint_auto_delete (stop_bpstat); + + /* If an auto-display called a function and that got a signal, + delete that auto-display to avoid an infinite recursion. */ + + if (stopped_by_random_signal) + disable_current_display (); + + if (step_multi && stop_step) + return; + + target_terminal_ours (); + + if (!target_has_stack) + return; + + /* Select innermost stack frame except on return from a stack dummy routine, + or if the program has exited. */ + if (!stop_stack_dummy) + { + select_frame (get_current_frame (), 0); + + if (stop_print_frame) + { + int source_only = bpstat_print (stop_bpstat); + print_sel_frame + (source_only + || (stop_step + && step_frame_address == stop_frame_address + && step_start_function == find_pc_function (stop_pc))); + + /* Display the auto-display expressions. */ + do_displays (); + } + } + + /* Save the function value return registers, if we care. + We might be about to restore their previous contents. */ + if (proceed_to_finish) + read_register_bytes (0, stop_registers, REGISTER_BYTES); + + if (stop_stack_dummy) + { + /* Pop the empty frame that contains the stack dummy. + POP_FRAME ends with a setting of the current frame, so we + can use that next. */ + POP_FRAME; + select_frame (get_current_frame (), 0); + } +} + +static void +insert_step_breakpoint () +{ + if (step_resume_break_address && !step_resume_break_duplicate) + target_insert_breakpoint (step_resume_break_address, + step_resume_break_shadow); +} + +static void +remove_step_breakpoint () +{ + if (step_resume_break_address && !step_resume_break_duplicate) + target_remove_breakpoint (step_resume_break_address, + step_resume_break_shadow); +} + +static void +sig_print_header () +{ + printf_filtered ("Signal\t\tStop\tPrint\tPass to program\tDescription\n"); +} + +static void +sig_print_info (number) + int number; +{ + char *abbrev = sig_abbrev(number); + if (abbrev == NULL) + printf_filtered ("%d\t\t", number); + else + printf_filtered ("SIG%s (%d)\t", abbrev, number); + printf_filtered ("%s\t", signal_stop[number] ? "Yes" : "No"); + printf_filtered ("%s\t", signal_print[number] ? "Yes" : "No"); + printf_filtered ("%s\t\t", signal_program[number] ? "Yes" : "No"); + printf_filtered ("%s\n", sys_siglist[number]); +} + +/* Specify how various signals in the inferior should be handled. */ + +static void +handle_command (args, from_tty) + char *args; + int from_tty; +{ + register char *p = args; + int signum = 0; + register int digits, wordlen; + char *nextarg; + + if (!args) + error_no_arg ("signal to handle"); + + while (*p) + { + /* Find the end of the next word in the args. */ + for (wordlen = 0; + p[wordlen] && p[wordlen] != ' ' && p[wordlen] != '\t'; + wordlen++); + /* Set nextarg to the start of the word after the one we just + found, and null-terminate this one. */ + if (p[wordlen] == '\0') + nextarg = p + wordlen; + else + { + p[wordlen] = '\0'; + nextarg = p + wordlen + 1; + } + + + for (digits = 0; p[digits] >= '0' && p[digits] <= '9'; digits++); + + if (signum == 0) + { + /* It is the first argument--must be the signal to operate on. */ + if (digits == wordlen) + { + /* Numeric. */ + signum = atoi (p); + if (signum <= 0 || signum >= NSIG) + { + p[wordlen] = '\0'; + error ("Invalid signal %s given as argument to \"handle\".", p); + } + } + else + { + /* Symbolic. */ + signum = sig_number (p); + if (signum == -1) + error ("No such signal \"%s\"", p); + } + + if (signum == SIGTRAP || signum == SIGINT) + { + if (!query ("SIG%s is used by the debugger.\nAre you sure you want to change it? ", sig_abbrev (signum))) + error ("Not confirmed."); + } + } + /* Else, if already got a signal number, look for flag words + saying what to do for it. */ + else if (!strncmp (p, "stop", wordlen)) + { + signal_stop[signum] = 1; + signal_print[signum] = 1; + } + else if (wordlen >= 2 && !strncmp (p, "print", wordlen)) + signal_print[signum] = 1; + else if (wordlen >= 2 && !strncmp (p, "pass", wordlen)) + signal_program[signum] = 1; + else if (!strncmp (p, "ignore", wordlen)) + signal_program[signum] = 0; + else if (wordlen >= 3 && !strncmp (p, "nostop", wordlen)) + signal_stop[signum] = 0; + else if (wordlen >= 4 && !strncmp (p, "noprint", wordlen)) + { + signal_print[signum] = 0; + signal_stop[signum] = 0; + } + else if (wordlen >= 4 && !strncmp (p, "nopass", wordlen)) + signal_program[signum] = 0; + else if (wordlen >= 3 && !strncmp (p, "noignore", wordlen)) + signal_program[signum] = 1; + /* Not a number and not a recognized flag word => complain. */ + else + { + error ("Unrecognized flag word: \"%s\".", p); + } + + /* Find start of next word. */ + p = nextarg; + while (*p == ' ' || *p == '\t') p++; + } + + if (from_tty) + { + /* Show the results. */ + sig_print_header (); + sig_print_info (signum); + } +} + +/* Print current contents of the tables set by the handle command. */ + +static void +signals_info (signum_exp) + char *signum_exp; +{ + register int i; + sig_print_header (); + + if (signum_exp) + { + /* First see if this is a symbol name. */ + i = sig_number (signum_exp); + if (i == -1) + { + /* Nope, maybe it's an address which evaluates to a signal + number. */ + i = parse_and_eval_address (signum_exp); + if (i >= NSIG || i < 0) + error ("Signal number out of bounds."); + } + sig_print_info (i); + return; + } + + printf_filtered ("\n"); + for (i = 0; i < NSIG; i++) + { + QUIT; + + sig_print_info (i); + } + + printf_filtered ("\nUse the \"handle\" command to change these tables.\n"); +} + +/* Save all of the information associated with the inferior<==>gdb + connection. INF_STATUS is a pointer to a "struct inferior_status" + (defined in inferior.h). */ + +void +save_inferior_status (inf_status, restore_stack_info) + struct inferior_status *inf_status; + int restore_stack_info; +{ + inf_status->pc_changed = pc_changed; + inf_status->stop_signal = stop_signal; + inf_status->stop_pc = stop_pc; + inf_status->stop_frame_address = stop_frame_address; + inf_status->stop_step = stop_step; + inf_status->stop_stack_dummy = stop_stack_dummy; + inf_status->stopped_by_random_signal = stopped_by_random_signal; + inf_status->trap_expected = trap_expected; + inf_status->step_range_start = step_range_start; + inf_status->step_range_end = step_range_end; + inf_status->step_frame_address = step_frame_address; + inf_status->step_over_calls = step_over_calls; + inf_status->step_resume_break_address = step_resume_break_address; + inf_status->stop_after_trap = stop_after_trap; + inf_status->stop_soon_quietly = stop_soon_quietly; + /* Save original bpstat chain here; replace it with copy of chain. + If caller's caller is walking the chain, they'll be happier if we + hand them back the original chain when restore_i_s is called. */ + inf_status->stop_bpstat = stop_bpstat; + stop_bpstat = bpstat_copy (stop_bpstat); + inf_status->breakpoint_proceeded = breakpoint_proceeded; + inf_status->restore_stack_info = restore_stack_info; + inf_status->proceed_to_finish = proceed_to_finish; + + bcopy (stop_registers, inf_status->stop_registers, REGISTER_BYTES); + + record_selected_frame (&(inf_status->selected_frame_address), + &(inf_status->selected_level)); + return; +} + +void +restore_inferior_status (inf_status) + struct inferior_status *inf_status; +{ + FRAME fid; + int level = inf_status->selected_level; + + pc_changed = inf_status->pc_changed; + stop_signal = inf_status->stop_signal; + stop_pc = inf_status->stop_pc; + stop_frame_address = inf_status->stop_frame_address; + stop_step = inf_status->stop_step; + stop_stack_dummy = inf_status->stop_stack_dummy; + stopped_by_random_signal = inf_status->stopped_by_random_signal; + trap_expected = inf_status->trap_expected; + step_range_start = inf_status->step_range_start; + step_range_end = inf_status->step_range_end; + step_frame_address = inf_status->step_frame_address; + step_over_calls = inf_status->step_over_calls; + step_resume_break_address = inf_status->step_resume_break_address; + stop_after_trap = inf_status->stop_after_trap; + stop_soon_quietly = inf_status->stop_soon_quietly; + bpstat_clear (&stop_bpstat); + stop_bpstat = inf_status->stop_bpstat; + breakpoint_proceeded = inf_status->breakpoint_proceeded; + proceed_to_finish = inf_status->proceed_to_finish; + + bcopy (inf_status->stop_registers, stop_registers, REGISTER_BYTES); + + /* The inferior can be gone if the user types "print exit(0)" + (and perhaps other times). */ + if (target_has_stack && inf_status->restore_stack_info) + { + fid = find_relative_frame (get_current_frame (), + &level); + + if (fid == 0 || + FRAME_FP (fid) != inf_status->selected_frame_address || + level != 0) + { +#if 0 + /* I'm not sure this error message is a good idea. I have + only seen it occur after "Can't continue previously + requested operation" (we get called from do_cleanups), in + which case it just adds insult to injury (one confusing + error message after another. Besides which, does the + user really care if we can't restore the previously + selected frame? */ + fprintf (stderr, "Unable to restore previously selected frame.\n"); +#endif + select_frame (get_current_frame (), 0); + return; + } + + select_frame (fid, inf_status->selected_level); + } +} + + +void +_initialize_infrun () +{ + register int i; + + add_info ("signals", signals_info, + "What debugger does when program gets various signals.\n\ +Specify a signal number as argument to print info on that signal only."); + + add_com ("handle", class_run, handle_command, + "Specify how to handle a signal.\n\ +Args are signal number followed by flags.\n\ +Flags allowed are \"stop\", \"print\", \"pass\",\n\ + \"nostop\", \"noprint\" or \"nopass\".\n\ +Print means print a message if this signal happens.\n\ +Stop means reenter debugger if this signal happens (implies print).\n\ +Pass means let program see this signal; otherwise program doesn't know.\n\ +Pass and Stop may be combined."); + + for (i = 0; i < NSIG; i++) + { + signal_stop[i] = 1; + signal_print[i] = 1; + signal_program[i] = 1; + } + + /* Signals caused by debugger's own actions + should not be given to the program afterwards. */ + signal_program[SIGTRAP] = 0; + signal_program[SIGINT] = 0; + + /* Signals that are not errors should not normally enter the debugger. */ +#ifdef SIGALRM + signal_stop[SIGALRM] = 0; + signal_print[SIGALRM] = 0; +#endif /* SIGALRM */ +#ifdef SIGVTALRM + signal_stop[SIGVTALRM] = 0; + signal_print[SIGVTALRM] = 0; +#endif /* SIGVTALRM */ +#ifdef SIGPROF + signal_stop[SIGPROF] = 0; + signal_print[SIGPROF] = 0; +#endif /* SIGPROF */ +#ifdef SIGCHLD + signal_stop[SIGCHLD] = 0; + signal_print[SIGCHLD] = 0; +#endif /* SIGCHLD */ +#ifdef SIGCLD + signal_stop[SIGCLD] = 0; + signal_print[SIGCLD] = 0; +#endif /* SIGCLD */ +#ifdef SIGIO + signal_stop[SIGIO] = 0; + signal_print[SIGIO] = 0; +#endif /* SIGIO */ +#ifdef SIGURG + signal_stop[SIGURG] = 0; + signal_print[SIGURG] = 0; +#endif /* SIGURG */ +} + |