+
+/* Exception handling support for the HP-UX ANSI C++ compiler.
+ The compiler (aCC) provides a callback for exception events;
+ GDB can set a breakpoint on this callback and find out what
+ exception event has occurred. */
+
+/* The name of the hook to be set to point to the callback function */
+static char HP_ACC_EH_notify_hook[] = "__eh_notify_hook";
+/* The name of the function to be used to set the hook value */
+static char HP_ACC_EH_set_hook_value[] = "__eh_set_hook_value";
+/* The name of the callback function in end.o */
+static char HP_ACC_EH_notify_callback[] = "__d_eh_notify_callback";
+/* Name of function in end.o on which a break is set (called by above) */
+static char HP_ACC_EH_break[] = "__d_eh_break";
+/* Name of flag (in end.o) that enables catching throws */
+static char HP_ACC_EH_catch_throw[] = "__d_eh_catch_throw";
+/* Name of flag (in end.o) that enables catching catching */
+static char HP_ACC_EH_catch_catch[] = "__d_eh_catch_catch";
+/* The enum used by aCC */
+typedef enum
+ {
+ __EH_NOTIFY_THROW,
+ __EH_NOTIFY_CATCH
+ }
+__eh_notification;
+
+/* Is exception-handling support available with this executable? */
+static int hp_cxx_exception_support = 0;
+/* Has the initialize function been run? */
+int hp_cxx_exception_support_initialized = 0;
+/* Similar to above, but imported from breakpoint.c -- non-target-specific */
+extern int exception_support_initialized;
+/* Address of __eh_notify_hook */
+static CORE_ADDR eh_notify_hook_addr = 0;
+/* Address of __d_eh_notify_callback */
+static CORE_ADDR eh_notify_callback_addr = 0;
+/* Address of __d_eh_break */
+static CORE_ADDR eh_break_addr = 0;
+/* Address of __d_eh_catch_catch */
+static CORE_ADDR eh_catch_catch_addr = 0;
+/* Address of __d_eh_catch_throw */
+static CORE_ADDR eh_catch_throw_addr = 0;
+/* Sal for __d_eh_break */
+static struct symtab_and_line *break_callback_sal = 0;
+
+/* Code in end.c expects __d_pid to be set in the inferior,
+ otherwise __d_eh_notify_callback doesn't bother to call
+ __d_eh_break! So we poke the pid into this symbol
+ ourselves.
+ 0 => success
+ 1 => failure */
+int
+setup_d_pid_in_inferior (void)
+{
+ CORE_ADDR anaddr;
+ struct minimal_symbol *msymbol;
+ char buf[4]; /* FIXME 32x64? */
+
+ /* Slam the pid of the process into __d_pid; failing is only a warning! */
+ msymbol = lookup_minimal_symbol ("__d_pid", NULL, symfile_objfile);
+ if (msymbol == NULL)
+ {
+ warning ("Unable to find __d_pid symbol in object file.");
+ warning ("Suggest linking executable with -g (links in /opt/langtools/lib/end.o).");
+ return 1;
+ }
+
+ anaddr = SYMBOL_VALUE_ADDRESS (msymbol);
+ store_unsigned_integer (buf, 4, PIDGET (inferior_ptid)); /* FIXME 32x64? */
+ if (target_write_memory (anaddr, buf, 4)) /* FIXME 32x64? */
+ {
+ warning ("Unable to write __d_pid");
+ warning ("Suggest linking executable with -g (links in /opt/langtools/lib/end.o).");
+ return 1;
+ }
+ return 0;
+}
+
+/* Initialize exception catchpoint support by looking for the
+ necessary hooks/callbacks in end.o, etc., and set the hook value to
+ point to the required debug function
+
+ Return 0 => failure
+ 1 => success */
+
+static int
+initialize_hp_cxx_exception_support (void)
+{
+ struct symtabs_and_lines sals;
+ struct cleanup *old_chain;
+ struct cleanup *canonical_strings_chain = NULL;
+ int i;
+ char *addr_start;
+ char *addr_end = NULL;
+ char **canonical = (char **) NULL;
+ int thread = -1;
+ struct symbol *sym = NULL;
+ struct minimal_symbol *msym = NULL;
+ struct objfile *objfile;
+ asection *shlib_info;
+
+ /* Detect and disallow recursion. On HP-UX with aCC, infinite
+ recursion is a possibility because finding the hook for exception
+ callbacks involves making a call in the inferior, which means
+ re-inserting breakpoints which can re-invoke this code */
+
+ static int recurse = 0;
+ if (recurse > 0)
+ {
+ hp_cxx_exception_support_initialized = 0;
+ exception_support_initialized = 0;
+ return 0;
+ }
+
+ hp_cxx_exception_support = 0;
+
+ /* First check if we have seen any HP compiled objects; if not,
+ it is very unlikely that HP's idiosyncratic callback mechanism
+ for exception handling debug support will be available!
+ This will percolate back up to breakpoint.c, where our callers
+ will decide to try the g++ exception-handling support instead. */
+ if (!hp_som_som_object_present)
+ return 0;
+
+ /* We have a SOM executable with SOM debug info; find the hooks */
+
+ /* First look for the notify hook provided by aCC runtime libs */
+ /* If we find this symbol, we conclude that the executable must
+ have HP aCC exception support built in. If this symbol is not
+ found, even though we're a HP SOM-SOM file, we may have been
+ built with some other compiler (not aCC). This results percolates
+ back up to our callers in breakpoint.c which can decide to
+ try the g++ style of exception support instead.
+ If this symbol is found but the other symbols we require are
+ not found, there is something weird going on, and g++ support
+ should *not* be tried as an alternative.
+
+ ASSUMPTION: Only HP aCC code will have __eh_notify_hook defined.
+ ASSUMPTION: HP aCC and g++ modules cannot be linked together. */
+
+ /* libCsup has this hook; it'll usually be non-debuggable */
+ msym = lookup_minimal_symbol (HP_ACC_EH_notify_hook, NULL, NULL);
+ if (msym)
+ {
+ eh_notify_hook_addr = SYMBOL_VALUE_ADDRESS (msym);
+ hp_cxx_exception_support = 1;
+ }
+ else
+ {
+ warning ("Unable to find exception callback hook (%s).", HP_ACC_EH_notify_hook);
+ warning ("Executable may not have been compiled debuggable with HP aCC.");
+ warning ("GDB will be unable to intercept exception events.");
+ eh_notify_hook_addr = 0;
+ hp_cxx_exception_support = 0;
+ return 0;
+ }
+
+ /* Next look for the notify callback routine in end.o */
+ /* This is always available in the SOM symbol dictionary if end.o is linked in */
+ msym = lookup_minimal_symbol (HP_ACC_EH_notify_callback, NULL, NULL);
+ if (msym)
+ {
+ eh_notify_callback_addr = SYMBOL_VALUE_ADDRESS (msym);
+ hp_cxx_exception_support = 1;
+ }
+ else
+ {
+ warning ("Unable to find exception callback routine (%s).", HP_ACC_EH_notify_callback);
+ warning ("Suggest linking executable with -g (links in /opt/langtools/lib/end.o).");
+ warning ("GDB will be unable to intercept exception events.");
+ eh_notify_callback_addr = 0;
+ return 0;
+ }
+
+#ifndef GDB_TARGET_IS_HPPA_20W
+ /* Check whether the executable is dynamically linked or archive bound */
+ /* With an archive-bound executable we can use the raw addresses we find
+ for the callback function, etc. without modification. For an executable
+ with shared libraries, we have to do more work to find the plabel, which
+ can be the target of a call through $$dyncall from the aCC runtime support
+ library (libCsup) which is linked shared by default by aCC. */
+ /* This test below was copied from somsolib.c/somread.c. It may not be a very
+ reliable one to test that an executable is linked shared. pai/1997-07-18 */
+ shlib_info = bfd_get_section_by_name (symfile_objfile->obfd, "$SHLIB_INFO$");
+ if (shlib_info && (bfd_section_size (symfile_objfile->obfd, shlib_info) != 0))
+ {
+ /* The minsym we have has the local code address, but that's not the
+ plabel that can be used by an inter-load-module call. */
+ /* Find solib handle for main image (which has end.o), and use that
+ and the min sym as arguments to __d_shl_get() (which does the equivalent
+ of shl_findsym()) to find the plabel. */
+
+ args_for_find_stub args;
+ static char message[] = "Error while finding exception callback hook:\n";
+
+ args.solib_handle = som_solib_get_solib_by_pc (eh_notify_callback_addr);
+ args.msym = msym;
+ args.return_val = 0;
+
+ recurse++;
+ catch_errors (cover_find_stub_with_shl_get, (PTR) &args, message,
+ RETURN_MASK_ALL);
+ eh_notify_callback_addr = args.return_val;
+ recurse--;
+
+ exception_catchpoints_are_fragile = 1;
+
+ if (!eh_notify_callback_addr)
+ {
+ /* We can get here either if there is no plabel in the export list
+ for the main image, or if something strange happened (?) */
+ warning ("Couldn't find a plabel (indirect function label) for the exception callback.");
+ warning ("GDB will not be able to intercept exception events.");
+ return 0;
+ }
+ }
+ else
+ exception_catchpoints_are_fragile = 0;
+#endif
+
+ /* Now, look for the breakpointable routine in end.o */
+ /* This should also be available in the SOM symbol dict. if end.o linked in */
+ msym = lookup_minimal_symbol (HP_ACC_EH_break, NULL, NULL);
+ if (msym)
+ {
+ eh_break_addr = SYMBOL_VALUE_ADDRESS (msym);
+ hp_cxx_exception_support = 1;
+ }
+ else
+ {
+ warning ("Unable to find exception callback routine to set breakpoint (%s).", HP_ACC_EH_break);
+ warning ("Suggest linking executable with -g (link in /opt/langtools/lib/end.o).");
+ warning ("GDB will be unable to intercept exception events.");
+ eh_break_addr = 0;
+ return 0;
+ }
+
+ /* Next look for the catch enable flag provided in end.o */
+ sym = lookup_symbol (HP_ACC_EH_catch_catch, (struct block *) NULL,
+ VAR_NAMESPACE, 0, (struct symtab **) NULL);
+ if (sym) /* sometimes present in debug info */
+ {
+ eh_catch_catch_addr = SYMBOL_VALUE_ADDRESS (sym);
+ hp_cxx_exception_support = 1;
+ }
+ else
+ /* otherwise look in SOM symbol dict. */
+ {
+ msym = lookup_minimal_symbol (HP_ACC_EH_catch_catch, NULL, NULL);
+ if (msym)
+ {
+ eh_catch_catch_addr = SYMBOL_VALUE_ADDRESS (msym);
+ hp_cxx_exception_support = 1;
+ }
+ else
+ {
+ warning ("Unable to enable interception of exception catches.");
+ warning ("Executable may not have been compiled debuggable with HP aCC.");
+ warning ("Suggest linking executable with -g (link in /opt/langtools/lib/end.o).");
+ return 0;
+ }
+ }
+
+ /* Next look for the catch enable flag provided end.o */
+ sym = lookup_symbol (HP_ACC_EH_catch_catch, (struct block *) NULL,
+ VAR_NAMESPACE, 0, (struct symtab **) NULL);
+ if (sym) /* sometimes present in debug info */
+ {
+ eh_catch_throw_addr = SYMBOL_VALUE_ADDRESS (sym);
+ hp_cxx_exception_support = 1;
+ }
+ else
+ /* otherwise look in SOM symbol dict. */
+ {
+ msym = lookup_minimal_symbol (HP_ACC_EH_catch_throw, NULL, NULL);
+ if (msym)
+ {
+ eh_catch_throw_addr = SYMBOL_VALUE_ADDRESS (msym);
+ hp_cxx_exception_support = 1;
+ }
+ else
+ {
+ warning ("Unable to enable interception of exception throws.");
+ warning ("Executable may not have been compiled debuggable with HP aCC.");
+ warning ("Suggest linking executable with -g (link in /opt/langtools/lib/end.o).");
+ return 0;
+ }
+ }
+
+ /* Set the flags */
+ hp_cxx_exception_support = 2; /* everything worked so far */
+ hp_cxx_exception_support_initialized = 1;
+ exception_support_initialized = 1;
+
+ return 1;
+}
+
+/* Target operation for enabling or disabling interception of
+ exception events.
+ KIND is either EX_EVENT_THROW or EX_EVENT_CATCH
+ ENABLE is either 0 (disable) or 1 (enable).
+ Return value is NULL if no support found;
+ -1 if something went wrong,
+ or a pointer to a symtab/line struct if the breakpointable
+ address was found. */
+
+struct symtab_and_line *
+child_enable_exception_callback (enum exception_event_kind kind, int enable)
+{
+ char buf[4];
+
+ if (!exception_support_initialized || !hp_cxx_exception_support_initialized)
+ if (!initialize_hp_cxx_exception_support ())
+ return NULL;
+
+ switch (hp_cxx_exception_support)
+ {
+ case 0:
+ /* Assuming no HP support at all */
+ return NULL;
+ case 1:
+ /* HP support should be present, but something went wrong */
+ return (struct symtab_and_line *) -1; /* yuck! */
+ /* there may be other cases in the future */
+ }
+
+ /* Set the EH hook to point to the callback routine */
+ store_unsigned_integer (buf, 4, enable ? eh_notify_callback_addr : 0); /* FIXME 32x64 problem */
+ /* pai: (temp) FIXME should there be a pack operation first? */
+ if (target_write_memory (eh_notify_hook_addr, buf, 4)) /* FIXME 32x64 problem */
+ {
+ warning ("Could not write to target memory for exception event callback.");
+ warning ("Interception of exception events may not work.");
+ return (struct symtab_and_line *) -1;
+ }
+ if (enable)
+ {
+ /* Ensure that __d_pid is set up correctly -- end.c code checks this. :-( */
+ if (PIDGET (inferior_ptid) > 0)
+ {
+ if (setup_d_pid_in_inferior ())
+ return (struct symtab_and_line *) -1;
+ }
+ else
+ {
+ warning ("Internal error: Invalid inferior pid? Cannot intercept exception events.");
+ return (struct symtab_and_line *) -1;
+ }
+ }
+
+ switch (kind)
+ {
+ case EX_EVENT_THROW:
+ store_unsigned_integer (buf, 4, enable ? 1 : 0);
+ if (target_write_memory (eh_catch_throw_addr, buf, 4)) /* FIXME 32x64? */
+ {
+ warning ("Couldn't enable exception throw interception.");
+ return (struct symtab_and_line *) -1;
+ }
+ break;
+ case EX_EVENT_CATCH:
+ store_unsigned_integer (buf, 4, enable ? 1 : 0);
+ if (target_write_memory (eh_catch_catch_addr, buf, 4)) /* FIXME 32x64? */
+ {
+ warning ("Couldn't enable exception catch interception.");
+ return (struct symtab_and_line *) -1;
+ }
+ break;
+ default:
+ error ("Request to enable unknown or unsupported exception event.");
+ }
+
+ /* Copy break address into new sal struct, malloc'ing if needed. */
+ if (!break_callback_sal)
+ {
+ break_callback_sal = (struct symtab_and_line *) xmalloc (sizeof (struct symtab_and_line));
+ }
+ INIT_SAL (break_callback_sal);
+ break_callback_sal->symtab = NULL;
+ break_callback_sal->pc = eh_break_addr;
+ break_callback_sal->line = 0;
+ break_callback_sal->end = eh_break_addr;
+
+ return break_callback_sal;
+}
+
+/* Record some information about the current exception event */
+static struct exception_event_record current_ex_event;
+/* Convenience struct */
+static struct symtab_and_line null_symtab_and_line =
+{NULL, 0, 0, 0};
+
+/* Report current exception event. Returns a pointer to a record
+ that describes the kind of the event, where it was thrown from,
+ and where it will be caught. More information may be reported
+ in the future */
+struct exception_event_record *
+child_get_current_exception_event (void)
+{
+ CORE_ADDR event_kind;
+ CORE_ADDR throw_addr;
+ CORE_ADDR catch_addr;
+ struct frame_info *fi, *curr_frame;
+ int level = 1;
+
+ curr_frame = get_current_frame ();
+ if (!curr_frame)
+ return (struct exception_event_record *) NULL;
+
+ /* Go up one frame to __d_eh_notify_callback, because at the
+ point when this code is executed, there's garbage in the
+ arguments of __d_eh_break. */
+ fi = find_relative_frame (curr_frame, &level);
+ if (level != 0)
+ return (struct exception_event_record *) NULL;
+
+ select_frame (fi);
+
+ /* Read in the arguments */
+ /* __d_eh_notify_callback() is called with 3 arguments:
+ 1. event kind catch or throw
+ 2. the target address if known
+ 3. a flag -- not sure what this is. pai/1997-07-17 */
+ event_kind = read_register (ARG0_REGNUM);
+ catch_addr = read_register (ARG1_REGNUM);
+
+ /* Now go down to a user frame */
+ /* For a throw, __d_eh_break is called by
+ __d_eh_notify_callback which is called by
+ __notify_throw which is called
+ from user code.
+ For a catch, __d_eh_break is called by
+ __d_eh_notify_callback which is called by
+ <stackwalking stuff> which is called by
+ __throw__<stuff> or __rethrow_<stuff> which is called
+ from user code. */
+ /* FIXME: Don't use such magic numbers; search for the frames */
+ level = (event_kind == EX_EVENT_THROW) ? 3 : 4;
+ fi = find_relative_frame (curr_frame, &level);
+ if (level != 0)
+ return (struct exception_event_record *) NULL;
+
+ select_frame (fi);
+ throw_addr = fi->pc;
+
+ /* Go back to original (top) frame */
+ select_frame (curr_frame);
+
+ current_ex_event.kind = (enum exception_event_kind) event_kind;
+ current_ex_event.throw_sal = find_pc_line (throw_addr, 1);
+ current_ex_event.catch_sal = find_pc_line (catch_addr, 1);
+
+ return ¤t_ex_event;
+}