s-intman-posix.adb (Notify_Exception): Adjust signature, as handler for sigactions with SA_SIGINFO set.
2005-03-08 Olivier Hainque <hainque@adacore.com> * s-intman-posix.adb (Notify_Exception): Adjust signature, as handler for sigactions with SA_SIGINFO set. Call __gnat_adjust_context_for_raise before raising, to perform the potentially required adjustments to the machine context for the GCC unwinder. * raise.h (__gnat_adjust_context_for_raise): New prototype. * init.c (__gnat_adjust_context_for_raise) HPUX: Initial revision. Adjust PC by one in the provided machine context. (__gnat_install_handler) HPUX: Set SA_SIGINFO in the sigaction flags, so that the handler is passed the context structure to adjust prior to the raise. (__gnat_error_handler) HPUX: Adjust the signature to match what an SA_SIGINFO sigaction should look like. Call __gnat_adjust_context_for_raise before actually raising. (__gnat_adjust_context_for_raise): Default noop to help PC adjustments before raise from signal handlers. (__gnat_error_handler): Indirectly call a predicate function to determine if a condition should be resignaled or not. (__gnat_set_resignal_predicate): User interface to modify the predicate. (__gnat_default_resignal_p): Default GNAT predicate. From-SVN: r96482
This commit is contained in:
Olivier Hainque
Arnaud Charlet
parent
7e98a4c668
commit
3f8abd98ba
169
gcc/ada/init.c
169
gcc/ada/init.c
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@ -547,7 +547,7 @@ __gnat_initialize (void *eh ATTRIBUTE_UNUSED)
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{
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}
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/* Routines called by 5amastop.adb. */
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/* Routines called by s-mastop-tru64.adb. */
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#define SC_GP 29
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@ -578,11 +578,29 @@ __gnat_machine_state_length (void)
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#elif defined (__hpux__)
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#include <signal.h>
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static void __gnat_error_handler (int);
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#include <sys/ucontext.h>
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static void
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__gnat_error_handler (int sig)
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__gnat_error_handler (int sig, siginfo_t *siginfo, void *ucontext);
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/* __gnat_adjust_context_for_raise - see comments along with the default
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version later in this file. */
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#define HAVE_GNAT_ADJUST_CONTEXT_FOR_RAISE
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void
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__gnat_adjust_context_for_raise (int signo ATTRIBUTE_UNUSED, void *ucontext)
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{
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mcontext_t *mcontext = &((ucontext_t *) ucontext)->uc_mcontext;
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if (UseWideRegs (mcontext))
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mcontext->ss_wide.ss_32.ss_pcoq_head_lo ++;
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else
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mcontext->ss_narrow.ss_pcoq_head ++;
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}
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static void
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__gnat_error_handler (int sig, siginfo_t *siginfo, void *ucontext)
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{
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struct Exception_Data *exception;
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char *msg;
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@ -610,6 +628,8 @@ __gnat_error_handler (int sig)
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msg = "unhandled signal";
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}
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__gnat_adjust_context_for_raise (sig, ucontext);
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Raise_From_Signal_Handler (exception, msg);
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}
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@ -637,8 +657,8 @@ __gnat_install_handler (void)
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sigaltstack (&stack, NULL);
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act.sa_handler = __gnat_error_handler;
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act.sa_flags = SA_NODEFER | SA_RESTART | SA_ONSTACK;
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act.sa_sigaction = __gnat_error_handler;
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act.sa_flags = SA_NODEFER | SA_RESTART | SA_ONSTACK | SA_SIGINFO;
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sigemptyset (&act.sa_mask);
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/* Do not install handlers if interrupt state is "System" */
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@ -835,9 +855,16 @@ __gnat_initialize (void *eh ATTRIBUTE_UNUSED)
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implementation of __gnat_portable_no_block_spawn, __gnat_portable_wait */
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__gnat_plist_init();
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/* Note that we do not activate this for the compiler itself to avoid a
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bootstrap path problem. Older version of gnatbind will generate a call
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to __gnat_initialize() without argument. Therefore we cannot use eh in
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this case. It will be possible to remove the following #ifdef at some
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point. */
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#ifdef IN_RTS
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/* Install the Structured Exception handler. */
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if (eh)
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__gnat_install_SEH_handler (eh);
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#endif
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}
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/***************************************/
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@ -1285,6 +1312,70 @@ struct descriptor_s {unsigned short len, mbz; char *adr; };
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long __gnat_error_handler (int *, void *);
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/* To deal with VMS conditions and their mapping to Ada exceptions,
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the __gnat_error_handler routine below is installed as an exception
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vector having precedence over DEC frame handlers. Some conditions
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still need to be handled by such handlers, however, in which case
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__gnat_error_handler needs to return SS$_RESIGNAL. Consider for
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instance the use of a third party library compiled with DECAda and
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performing it's own exception handling internally.
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To allow some user-level flexibility, which conditions should be
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resignaled is controlled by a predicate function, provided with the
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condition value and returning a boolean indication stating whether
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this condition should be resignaled or not.
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That predicate function is called indirectly, via a function pointer,
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by __gnat_error_handler, and changing that pointer is allowed to the
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the user code by way of the __gnat_set_resignal_predicate interface.
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The user level function may then implement what it likes, including
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for instance the maintenance of a dynamic data structure if the set
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of to be resignalled conditions has to change over the program's
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lifetime.
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??? This is not a perfect solution to deal with the possible
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interactions between the GNAT and the DECAda exception handling
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models and better (more general) schemes are studied. This is so
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just provided as a conveniency workaround in the meantime, and
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should be use with caution since the implementation has been kept
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very simple. */
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typedef int
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resignal_predicate (int code);
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/* Default GNAT predicate for resignaling conditions. */
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static int
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__gnat_default_resignal_p (int code)
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{
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return
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code == CMA$_EXIT_THREAD
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|| code == SS$_DEBUG /* Gdb attach, resignal to merge activate gdbstub. */
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|| code == 1409786 /* Nickerson bug #33 ??? */
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|| code == 1381050 /* Nickerson bug #33 ??? */
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|| code == 20480426 /* RDB-E-STREAM_EOF */
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|| code == 11829410 /* Resignalled as Use_Error for CE10VRC */
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;
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}
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/* Static pointer to predicate that the __gnat_error_handler exception
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vector invokes to determine if it should resignal a condition. */
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static resignal_predicate * __gnat_resignal_p = __gnat_default_resignal_p;
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/* User interface to change the predicate pointer to PREDICATE. Reset to
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the default if PREDICATE is null. */
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void
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__gnat_set_resignal_predicate (resignal_predicate * predicate)
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{
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if (predicate == 0)
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__gnat_resignal_p = __gnat_default_resignal_p;
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else
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__gnat_resignal_p = predicate;
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}
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long
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__gnat_error_handler (int *sigargs, void *mechargs)
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{
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@ -1301,31 +1392,11 @@ __gnat_error_handler (int *sigargs, void *mechargs)
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long curr_invo_handle;
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long *mstate;
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/* Resignaled condtions aren't effected by by pragma Import_Exception */
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switch (sigargs[1])
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{
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case CMA$_EXIT_THREAD:
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/* Check for conditions to resignal which aren't effected by pragma
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Import_Exception. */
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if (__gnat_resignal_p (sigargs [1]))
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return SS$_RESIGNAL;
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case SS$_DEBUG: /* Gdb attach, resignal to merge activate gdbstub. */
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return SS$_RESIGNAL;
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case 1409786: /* Nickerson bug #33 ??? */
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return SS$_RESIGNAL;
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case 1381050: /* Nickerson bug #33 ??? */
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return SS$_RESIGNAL;
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case 20480426: /* RDB-E-STREAM_EOF */
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return SS$_RESIGNAL;
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case 11829410: /* Resignalled as Use_Error for CE10VRC */
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return SS$_RESIGNAL;
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}
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#ifdef IN_RTS
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/* See if it's an imported exception. Beware that registered exceptions
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are bound to their base code, with the severity bits masked off. */
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@ -1901,3 +1972,43 @@ __gnat_init_float (void)
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{
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}
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#endif
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/***********************************/
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/* __gnat_adjust_context_for_raise */
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/***********************************/
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#ifndef HAVE_GNAT_ADJUST_CONTEXT_FOR_RAISE
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/* All targets without a specific version will use an empty one */
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/* UCONTEXT is a pointer to a context structure received by a signal handler
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about to propagate an exception. Adjust it to compensate the fact that the
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generic unwinder thinks the corresponding PC is a call return address. */
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void
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__gnat_adjust_context_for_raise (int signo ATTRIBUTE_UNUSED,
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void *ucontext ATTRIBUTE_UNUSED)
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{
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/* The point is that the interrupted context PC typically is the address
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that we should search an EH region for, which is different from the call
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return address case. The target independant part of the GCC unwinder
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don't differentiate the two situations, so we compensate here for the
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adjustments it will blindly make.
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signo is passed because on some targets for some signals the PC in
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context points to the instruction after the faulting one, in which case
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the unwinder adjustment is still desired. */
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/* On a number of targets, we have arranged for the adjustment to be
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performed by the MD_FALLBACK_FRAME_STATE circuitry, so we don't provide a
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specific instance of this routine. The MD_FALLBACK doesn't have access
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to the signal number, though, so the compensation is systematic there and
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might be wrong in some cases. */
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/* Having the compensation wrong leads to potential failures. A very
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typical case is what happens when there is no compensation and a signal
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triggers for the first instruction in a region : the unwinder adjustment
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has it search in the wrong EH region. */
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}
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#endif
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@ -70,5 +70,6 @@ extern void __gnat_initialize (void *);
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extern void __gnat_init_float (void);
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extern void __gnat_install_handler (void);
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extern void __gnat_install_SEH_handler (void *);
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extern void __gnat_adjust_context_for_raise (int, void *);
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extern int gnat_exit_status;
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@ -6,7 +6,7 @@
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-- --
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-- B o d y --
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-- --
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-- Copyright (C) 1992-2003, Free Software Foundation, Inc. --
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-- Copyright (C) 1992-2005, Free Software Foundation, Inc. --
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-- --
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-- GNARL is free software; you can redistribute it and/or modify it under --
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-- terms of the GNU General Public License as published by the Free Soft- --
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@ -88,7 +88,10 @@ package body System.Interrupt_Management is
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-- Local Subprograms --
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-----------------------
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procedure Notify_Exception (signo : Signal);
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procedure Notify_Exception
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(signo : Signal;
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siginfo : System.Address;
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ucontext : System.Address);
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-- This function identifies the Ada exception to be raised using
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-- the information when the system received a synchronous signal.
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-- Since this function is machine and OS dependent, different code
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@ -101,7 +104,24 @@ package body System.Interrupt_Management is
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Signal_Mask : aliased sigset_t;
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-- The set of signals handled by Notify_Exception
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procedure Notify_Exception (signo : Signal) is
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procedure Notify_Exception
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(signo : Signal;
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siginfo : System.Address;
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ucontext : System.Address)
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is
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pragma Unreferenced (siginfo);
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-- The GCC unwinder requires adjustments to the signal's machine
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-- context to be able to properly unwind through the signal handler.
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-- This is achieved by the target specific subprogram below, provided
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-- by init.c to be usable by the non-tasking handler also.
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procedure Adjust_Context_For_Raise
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(signo : Signal;
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ucontext : System.Address);
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pragma Import
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(C, Adjust_Context_For_Raise, "__gnat_adjust_context_for_raise");
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Result : Interfaces.C.int;
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begin
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@ -111,6 +131,11 @@ package body System.Interrupt_Management is
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Result := pthread_sigmask (SIG_UNBLOCK, Signal_Mask'Access, null);
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pragma Assert (Result = 0);
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-- Perform the necessary context adjustments required by the GCC/ZCX
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-- unwinder, harmless in the SJLJ case.
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Adjust_Context_For_Raise (signo, ucontext);
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-- Check that treatment of exception propagation here
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-- is consistent with treatment of the abort signal in
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-- System.Task_Primitives.Operations.
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@ -179,12 +204,12 @@ begin
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-- Setting SA_SIGINFO asks the kernel to pass more than just the signal
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-- number argument to the handler when it is called. The set of extra
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-- parameters typically includes a pointer to a structure describing
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-- the interrupted context. Although the Notify_Exception handler does
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-- not use this information, it is actually required for the GCC/ZCX
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-- exception propagation scheme because on some targets (at least
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-- alpha-tru64), the structure contents are not even filled when this
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-- flag is not set.
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-- parameters includes a pointer to the interrupted context, which the
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-- ZCX propagation scheme needs.
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-- Most man pages for sigaction mention that sa_sigaction should be set
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-- instead of sa_handler when SA_SIGINFO is on. In practice, the two
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-- fields are actually union'ed and located at the same offset.
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-- On some targets, we set sa_flags to SA_NODEFER so that during the
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-- handler execution we do not change the Signal_Mask to be masked for
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