2009-06-15 Phil Muldoon <pmuldoon@redhat.com>
* infcall.c (show_unwind_on_terminating_exception_p): New function. (call_function_by_hand): Create breakpoint and clean-up call for std::terminate.breakpoint. Add unwind_on_terminating_exception_p gate. Pop frame on breakpoint hit. (_initialize_infcall): Add add_setshow_boolean_cmd for unwind-on-terminating-exception. testsuite/ 2009-06-15 Phil Muldoon <pmuldoon@redhat.com> * gdb.cp/gdb2495.cc: New file. * gdb.cp/gdb2495.exp: New file. doc/ 2009-06-15 Phil Muldoon <pmuldoon@redhat.com> * doc/gdb.texinfo (Calling): Document set-unwind-on-terminating-exception usage.
This commit is contained in:
Phil Muldoon
parent
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commit
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@ -1,3 +1,13 @@
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2009-06-15 Phil Muldoon <pmuldoon@redhat.com>
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* infcall.c (show_unwind_on_terminating_exception_p): New
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function.
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(call_function_by_hand): Create breakpoint and clean-up call for
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std::terminate.breakpoint. Add unwind_on_terminating_exception_p
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gate. Pop frame on breakpoint hit.
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(_initialize_infcall): Add add_setshow_boolean_cmd for
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unwind-on-terminating-exception.
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2009-06-12 Kevin Buettner <kevinb@redhat.com>
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* dwarf2read.c (dwarf2_psymtab_to_symtab): Propagate
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@ -1,3 +1,8 @@
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2009-06-15 Phil Muldoon <pmuldoon@redhat.com>
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* doc/gdb.texinfo (Calling): Document
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set-unwind-on-terminating-exception usage.
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2009-06-11 Pedro Alves <pedro@codesourcery.com>
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* gdb.texinfo (All-Stop): Document new 'set schedule-multiple'
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@ -12895,6 +12895,16 @@ It is possible for the function you call via the @code{print} or
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the function, or if you passed it incorrect arguments). What happens
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in that case is controlled by the @code{set unwindonsignal} command.
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Similarly, with a C@t{++} program it is possible for the function you
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call via the @code{print} or @code{call} command to generate an
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exception that is not handled due to the constraints of the dummy
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frame. In this case, any exception that is raised in the frame, but has
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an out-of-frame exception handler will not be found. GDB builds a
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dummy-frame for the inferior function call, and the unwinder cannot
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seek for exception handlers outside of this dummy-frame. What happens
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in that case is controlled by the
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@code{set unwind-on-terminating-exception} command.
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@table @code
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@item set unwindonsignal
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@kindex set unwindonsignal
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@ -12911,6 +12921,23 @@ received.
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@kindex show unwindonsignal
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Show the current setting of stack unwinding in the functions called by
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@value{GDBN}.
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@item set unwind-on-terminating-exception
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@kindex set unwind-on-terminating-exception
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@cindex unwind stack in called functions with unhandled exceptions
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@cindex call dummy stack unwinding on unhandled exception.
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Set unwinding of the stack if a C@t{++} exception is raised, but left
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unhandled while in a function that @value{GDBN} called in the program being
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debugged. If set to on (the default), @value{GDBN} unwinds the stack
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it created for the call and restores the context to what it was before
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the call. If set to off, @value{GDBN} the exception is delivered to
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the default C@t{++} exception handler and the inferior terminated.
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@item show unwind-on-terminating-exception
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@kindex show unwind-on-terminating-exception
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Show the current setting of stack unwinding in the functions called by
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@value{GDBN}.
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@end table
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@cindex weak alias functions
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@ -98,6 +98,30 @@ Unwinding of stack if a signal is received while in a call dummy is %s.\n"),
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value);
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}
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/* This boolean tells what gdb should do if a std::terminate call is
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made while in a function called from gdb (call dummy).
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As the confines of a single dummy stack prohibit out-of-frame
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handlers from handling a raised exception, and as out-of-frame
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handlers are common in C++, this can lead to no handler being found
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by the unwinder, and a std::terminate call. This is a false positive.
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If set, gdb unwinds the stack and restores the context to what it
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was before the call.
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The default is to unwind the frame if a std::terminate call is
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made. */
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static int unwind_on_terminating_exception_p = 1;
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static void
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show_unwind_on_terminating_exception_p (struct ui_file *file, int from_tty,
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struct cmd_list_element *c,
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const char *value)
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{
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fprintf_filtered (file, _("\
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Unwind stack if a C++ exception is unhandled while in a call dummy is %s.\n"),
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value);
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}
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/* Perform the standard coercions that are specified
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for arguments to be passed to C or Ada functions.
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@ -416,6 +440,8 @@ call_function_by_hand (struct value *function, int nargs, struct value **args)
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struct cleanup *args_cleanup;
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struct frame_info *frame;
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struct gdbarch *gdbarch;
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struct breakpoint *terminate_bp = NULL;
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struct minimal_symbol *tm;
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ptid_t call_thread_ptid;
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struct gdb_exception e;
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const char *name;
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@ -716,6 +742,27 @@ call_function_by_hand (struct value *function, int nargs, struct value **args)
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bpt->disposition = disp_del;
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}
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/* Create a breakpoint in std::terminate.
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If a C++ exception is raised in the dummy-frame, and the
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exception handler is (normally, and expected to be) out-of-frame,
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the default C++ handler will (wrongly) be called in an inferior
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function call. This is wrong, as an exception can be normally
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and legally handled out-of-frame. The confines of the dummy frame
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prevent the unwinder from finding the correct handler (or any
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handler, unless it is in-frame). The default handler calls
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std::terminate. This will kill the inferior. Assert that
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terminate should never be called in an inferior function
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call. Place a momentary breakpoint in the std::terminate function
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and if triggered in the call, rewind. */
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if (unwind_on_terminating_exception_p)
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{
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struct minimal_symbol *tm = lookup_minimal_symbol ("std::terminate()",
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NULL, NULL);
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if (tm != NULL)
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terminate_bp = set_momentary_breakpoint_at_pc
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(SYMBOL_VALUE_ADDRESS (tm), bp_breakpoint);
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}
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/* Everything's ready, push all the info needed to restore the
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caller (and identify the dummy-frame) onto the dummy-frame
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stack. */
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@ -726,6 +773,10 @@ call_function_by_hand (struct value *function, int nargs, struct value **args)
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or discard it. */
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discard_cleanups (inf_status_cleanup);
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/* Register a clean-up for unwind_on_terminating_exception_breakpoint. */
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if (terminate_bp)
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make_cleanup_delete_breakpoint (terminate_bp);
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/* - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP -
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If you're looking to implement asynchronous dummy-frames, then
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just below is the place to chop this function in two.. */
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@ -881,6 +932,38 @@ When the function is done executing, GDB will silently stop."),
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if (!stop_stack_dummy)
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{
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/* Check if unwind on terminating exception behaviour is on. */
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if (unwind_on_terminating_exception_p)
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{
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/* Check that the breakpoint is our special std::terminate
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breakpoint. If it is, we do not want to kill the inferior
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in an inferior function call. Rewind, and warn the
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user. */
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if (terminate_bp != NULL
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&& (inferior_thread()->stop_bpstat->breakpoint_at->address
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== terminate_bp->loc->address))
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{
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/* We must get back to the frame we were before the
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dummy call. */
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dummy_frame_pop (dummy_id);
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/* We also need to restore inferior status to that before the
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dummy call. */
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restore_inferior_status (inf_status);
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error (_("\
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The program being debugged entered a std::terminate call, most likely\n\
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caused by an unhandled C++ exception. GDB blocked this call in order\n\
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to prevent the program from being terminated, and has restored the\n\
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context to its original state before the call.\n\
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To change this behaviour use \"set unwind-on-terminating-exception off\".\n\
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Evaluation of the expression containing the function (%s)\n\
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will be abandoned."),
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name);
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}
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}
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/* We hit a breakpoint inside the FUNCTION.
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Keep the dummy frame, the user may want to examine its state.
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Discard inferior status, we're not at the same point
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@ -989,4 +1072,19 @@ The default is to stop in the frame where the signal was received."),
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NULL,
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show_unwind_on_signal_p,
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&setlist, &showlist);
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add_setshow_boolean_cmd ("unwind-on-terminating-exception", no_class,
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&unwind_on_terminating_exception_p, _("\
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Set unwinding of stack if std::terminate is called while in call dummy."), _("\
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Show unwinding of stack if std::terminate() is called while in a call dummy."), _("\
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The unwind on terminating exception flag lets the user determine\n\
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what gdb should do if a std::terminate() call is made from the\n\
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default exception handler. If set, gdb unwinds the stack and restores\n\
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the context to what it was before the call. If unset, gdb allows the\n\
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std::terminate call to proceed.\n\
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The default is to unwind the frame."),
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NULL,
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show_unwind_on_terminating_exception_p,
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&setlist, &showlist);
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}
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@ -1,3 +1,8 @@
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2009-06-15 Phil Muldoon <pmuldoon@redhat.com>
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* gdb.cp/gdb2495.cc: New file.
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* gdb.cp/gdb2495.exp: New file.
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2009-06-12 Jan Kratochvil <jan.kratochvil@redhat.com>
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Report error on GDB crash during runto.
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@ -4,7 +4,7 @@ srcdir = @srcdir@
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EXECUTABLES = ambiguous annota2 anon-union cplusfuncs cttiadd \
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derivation inherit local member-ptr method misc \
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overload ovldbreak ref-typ ref-typ2 templates userdef virtfunc namespace \
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ref-types ref-params method2 pr9594
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ref-types ref-params method2 pr9594 gdb2495
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all info install-info dvi install uninstall installcheck check:
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@echo "Nothing to be done for $@..."
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89
gdb/testsuite/gdb.cp/gdb2495.cc
Normal file
89
gdb/testsuite/gdb.cp/gdb2495.cc
Normal file
@ -0,0 +1,89 @@
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/* This testcase is part of GDB, the GNU debugger.
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Copyright 2009 Free Software Foundation, Inc.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <iostream>
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#include <signal.h>
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using namespace std;
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class SimpleException
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{
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public:
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void raise_signal (int dummy)
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{
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if (dummy > 0)
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raise(SIGABRT);
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}
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int no_throw_function ()
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{
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return 1;
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}
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void throw_function ()
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{
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throw 1;
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}
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int throw_function_with_handler ()
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{
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try
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{
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throw 1;
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}
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catch (...)
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{
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cout << "Handled" << endl;
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}
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return 2;
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}
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void call_throw_function_no_handler ()
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{
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throw_function ();
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}
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void call_throw_function_handler ()
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{
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throw_function_with_handler ();
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}
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};
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SimpleException exceptions;
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int
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main()
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{
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/* Have to call these functions so GCC does not optimize them
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away. */
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exceptions.raise_signal (-1);
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exceptions.no_throw_function ();
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exceptions.throw_function_with_handler ();
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exceptions.call_throw_function_handler ();
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try
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||||
{
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exceptions.throw_function ();
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||||
exceptions.call_throw_function_no_handler ();
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||||
}
|
||||
catch (...)
|
||||
{
|
||||
}
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||||
return 0;
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||||
}
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157
gdb/testsuite/gdb.cp/gdb2495.exp
Normal file
157
gdb/testsuite/gdb.cp/gdb2495.exp
Normal file
@ -0,0 +1,157 @@
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# Copyright 2009 Free Software Foundation, Inc.
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# This program 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 3 of the License, or
|
||||
# (at your option) any later version.
|
||||
#
|
||||
# This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
|
||||
|
||||
|
||||
# In gdb inferior function calls, if a C++ exception is raised in the
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||||
# dummy-frame, and the exception handler is (normally, and expected to
|
||||
# be) out-of-frame, the default C++ handler will (wrongly) be called
|
||||
# in an inferior function call.
|
||||
# This is incorrect as an exception can normally and legally be handled
|
||||
# out-of-frame. The confines of the dummy frame prevent the unwinder
|
||||
# from finding the correct handler (or any handler, unless it is
|
||||
# in-frame). The default handler calls std::terminate. This will kill
|
||||
# the inferior. Assert that terminate should never be called in an
|
||||
# inferior function call. These tests test the functionality around
|
||||
# unwinding that sequence and also tests the flag behaviour gating this
|
||||
# functionality.
|
||||
|
||||
# This test is largely based of gdb.base/callfuncs.exp.
|
||||
|
||||
if $tracelevel then {
|
||||
strace $tracelevel
|
||||
}
|
||||
|
||||
if { [skip_cplus_tests] } { continue }
|
||||
|
||||
set prms_id 2495
|
||||
set bug_id 0
|
||||
|
||||
set testfile "gdb2495"
|
||||
set srcfile ${testfile}.cc
|
||||
set binfile $objdir/$subdir/$testfile
|
||||
|
||||
# Create and source the file that provides information about the compiler
|
||||
# used to compile the test case.
|
||||
if [get_compiler_info ${binfile} "c++"] {
|
||||
return -1
|
||||
}
|
||||
|
||||
if { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {debug c++}] != "" } {
|
||||
untested gdb2495.exp
|
||||
return -1
|
||||
}
|
||||
|
||||
# Some targets can't do function calls, so don't even bother with this
|
||||
# test.
|
||||
if [target_info exists gdb,cannot_call_functions] {
|
||||
setup_xfail "*-*-*" 2416
|
||||
fail "This target can not call functions"
|
||||
continue
|
||||
}
|
||||
|
||||
gdb_exit
|
||||
gdb_start
|
||||
gdb_reinitialize_dir $srcdir/$subdir
|
||||
gdb_load ${binfile}
|
||||
|
||||
if ![runto_main] then {
|
||||
perror "couldn't run to main"
|
||||
continue
|
||||
}
|
||||
|
||||
# See http://sourceware.org/gdb/bugs/2495
|
||||
|
||||
# Test normal baseline behaviour. Call a function that
|
||||
# does not raise an exception.
|
||||
gdb_test "p exceptions.no_throw_function()" " = 1"
|
||||
# And one that does but handles it in-frame.
|
||||
gdb_test "p exceptions.throw_function_with_handler()" " = 2"
|
||||
# Both should return normally.
|
||||
|
||||
# Test basic unwind. Call a function that raises an exception but
|
||||
# does not handle it. It should be rewound.
|
||||
gdb_test "p exceptions.throw_function()" \
|
||||
"The program being debugged entered a std::terminate call, .*" \
|
||||
"Call a function that raises an exception without a handler."
|
||||
|
||||
# Make sure that after rewinding we are back at the call parent.
|
||||
gdb_test "bt" \
|
||||
"#0 main.*" \
|
||||
"bt after returning from a popped frame"
|
||||
|
||||
# Make sure the only breakpoint is the one set via the runto_main
|
||||
# call and that the std::terminate breakpoint has evaporated and
|
||||
# cleaned-up.
|
||||
gdb_test "info breakpoints" \
|
||||
"gdb.cp/gdb2495\.cc.*"
|
||||
|
||||
# Turn off this new behaviour.
|
||||
gdb_test_multiple "set unwind-on-terminating-exception off" \
|
||||
"Turn unwind-on-terminating-exception off" {
|
||||
-re "$gdb_prompt $" {pass "set unwinn-on-terminating-exception off"}
|
||||
timeout {fail "(timeout) set unwind-on-terminating-exception off"}
|
||||
}
|
||||
|
||||
# Check that it is turned off.
|
||||
gdb_test "show unwind-on-terminating-exception" \
|
||||
"exception is unhandled while in a call dummy is off.*" \
|
||||
"Turn off unwind on terminating exception flag"
|
||||
|
||||
# Check that the old behaviour is restored.
|
||||
gdb_test "p exceptions.throw_function()" \
|
||||
"The program being debugged was signaled while in a function called .*" \
|
||||
"Call a function that raises an exception with unwinding off.."
|
||||
|
||||
# Restart the inferior back at main.
|
||||
if ![runto_main] then {
|
||||
perror "couldn't run to main"
|
||||
continue
|
||||
}
|
||||
|
||||
|
||||
# Check to see if the new behaviour alters the unwind signal
|
||||
# behaviour; it should not. Test both on and off states.
|
||||
|
||||
# Turn on unwind on signal behaviour.
|
||||
gdb_test_multiple "set unwindonsignal on" "Turn unwindonsignal on" {
|
||||
-re "$gdb_prompt $" {pass "set unwindonsignal on"}
|
||||
timeout {fail "(timeout) set unwindonsignal on"}
|
||||
}
|
||||
|
||||
# Check that it is turned on.
|
||||
gdb_test "show unwindonsignal" \
|
||||
"signal is received while in a call dummy is on.*" \
|
||||
"Turn on unwind on signal"
|
||||
|
||||
# Check to see if new behaviour interferes with
|
||||
# normal signal handling in inferior function calls.
|
||||
gdb_test "p exceptions.raise_signal(1)" \
|
||||
"To change this behavior use \"set unwindonsignal off\".*"
|
||||
|
||||
# And reverse - turn off again.
|
||||
gdb_test_multiple "set unwindonsignal off" "Turn unwindonsignal off" {
|
||||
-re "$gdb_prompt $" {pass "set unwindonsignal off"}
|
||||
timeout {fail "(timeout) set unwindonsignal off"}
|
||||
}
|
||||
|
||||
# Check that it is actually turned off.
|
||||
gdb_test "show unwindonsignal" \
|
||||
"signal is received while in a call dummy is off.*" \
|
||||
"Turn off unwind on signal"
|
||||
|
||||
# Check to see if new behaviour interferes with
|
||||
# normal signal handling in inferior function calls.
|
||||
gdb_test "p exceptions.raise_signal(1)" \
|
||||
"To change this behavior use \"set unwindonsignal on\".*"
|
||||
Loading…
x
Reference in New Issue
Block a user