return NULL;
}
+static CORE_ADDR
+hppa_hpux_som_find_global_pointer (struct value *function)
+{
+ CORE_ADDR faddr;
+
+ faddr = value_as_address (function);
+
+ /* Is this a plabel? If so, dereference it to get the gp value. */
+ if (faddr & 2)
+ {
+ int status;
+ char buf[4];
+
+ faddr &= ~3;
+
+ status = target_read_memory (faddr + 4, buf, sizeof (buf));
+ if (status == 0)
+ return extract_unsigned_integer (buf, sizeof (buf));
+ }
+
+ return som_solib_get_got_by_pc (faddr);
+}
+
+static CORE_ADDR
+hppa_hpux_push_dummy_code (struct gdbarch *gdbarch, CORE_ADDR sp,
+ CORE_ADDR funcaddr, int using_gcc,
+ struct value **args, int nargs,
+ struct type *value_type,
+ CORE_ADDR *real_pc, CORE_ADDR *bp_addr)
+{
+ /* FIXME: tausq/2004-06-09: This needs much more testing. It is broken
+ for pa64, but we should be able to get it to work with a little bit
+ of work. gdb-6.1 has a lot of code to handle various cases; I've tried to
+ simplify it and avoid compile-time conditionals. */
+
+ /* On HPUX, functions in the main executable and in libraries can be located
+ in different spaces. In order for us to be able to select the right
+ space for the function call, we need to go through an instruction seqeunce
+ to select the right space for the target function, call it, and then
+ restore the space on return.
+
+ There are two helper routines that can be used for this task -- if
+ an application is linked with gcc, it will contain a __gcc_plt_call
+ helper function. __gcc_plt_call, when passed the entry point of an
+ import stub, will do the necessary space setting/restoration for the
+ target function.
+
+ For programs that are compiled/linked with the HP compiler, a similar
+ function called __d_plt_call exists; __d_plt_call expects a PLABEL instead
+ of an import stub as an argument.
+
+ // *INDENT-OFF*
+ To summarize, the call flow is:
+ current function -> dummy frame -> __gcc_plt_call (import stub)
+ -> target function
+ or
+ current function -> dummy frame -> __d_plt_call (plabel)
+ -> target function
+ // *INDENT-ON*
+
+ In general the "funcaddr" argument passed to push_dummy_code is the actual
+ entry point of the target function. For __gcc_plt_call, we need to
+ locate the import stub for the corresponding function. Failing that,
+ we construct a dummy "import stub" on the stack to pass as an argument.
+ For __d_plt_call, we similarly synthesize a PLABEL on the stack to
+ pass to the helper function.
+
+ An additional twist is that, in order for us to restore the space register
+ to its starting state, we need __gcc_plt_call/__d_plt_call to return
+ to the instruction where we started the call. However, if we put
+ the breakpoint there, gdb will complain because it will find two
+ frames on the stack with the same (sp, pc) (with the dummy frame in
+ between). Currently, we set the return pointer to (pc - 4) of the
+ current function. FIXME: This is not an ideal solution; possibly if the
+ current pc is at the beginning of a page, this will cause a page fault.
+ Need to understand this better and figure out a better way to fix it. */
+
+ struct minimal_symbol *sym;
+
+ /* Nonzero if we will use GCC's PLT call routine. This routine must be
+ passed an import stub, not a PLABEL. It is also necessary to get %r19
+ before performing the call. (This is done by push_dummy_call.) */
+ int use_gcc_plt_call = 1;
+
+ /* See if __gcc_plt_call is available; if not we will use the HP version
+ instead. */
+ sym = lookup_minimal_symbol ("__gcc_plt_call", NULL, NULL);
+ if (sym == NULL)
+ use_gcc_plt_call = 0;
+
+ /* If using __gcc_plt_call, we need to make sure we pass in an import
+ stub. funcaddr can be pointing to an export stub or a real function,
+ so we try to resolve it to the import stub. */
+ if (use_gcc_plt_call)
+ {
+ struct objfile *objfile;
+ struct minimal_symbol *funsym, *stubsym;
+ CORE_ADDR stubaddr = 0;
+
+ funsym = lookup_minimal_symbol_by_pc (funcaddr);
+ if (!funsym)
+ error ("Unable to find symbol for target function.\n");
+
+ ALL_OBJFILES (objfile)
+ {
+ stubsym = lookup_minimal_symbol_solib_trampoline
+ (SYMBOL_LINKAGE_NAME (funsym), objfile);
+
+ if (stubsym)
+ {
+ struct unwind_table_entry *u;
+
+ u = find_unwind_entry (SYMBOL_VALUE (stubsym));
+ if (u == NULL
+ || (u->stub_unwind.stub_type != IMPORT
+ && u->stub_unwind.stub_type != IMPORT_SHLIB))
+ continue;
+
+ stubaddr = SYMBOL_VALUE (stubsym);
+
+ /* If we found an IMPORT stub, then we can stop searching;
+ if we found an IMPORT_SHLIB, we want to continue the search
+ in the hopes that we will find an IMPORT stub. */
+ if (u->stub_unwind.stub_type == IMPORT)
+ break;
+ }
+ }
+
+ if (stubaddr != 0)
+ {
+ /* Argument to __gcc_plt_call is passed in r22. */
+ regcache_cooked_write_unsigned (current_regcache, 22, stubaddr);
+ }
+ else
+ {
+ /* No import stub found; let's synthesize one. */
+
+ /* ldsid %r21, %r1 */
+ write_memory_unsigned_integer (sp, 4, 0x02a010a1);
+ /* mtsp %r1,%sr0 */
+ write_memory_unsigned_integer (sp + 4, 4, 0x00011820);
+ /* be 0(%sr0, %r21) */
+ write_memory_unsigned_integer (sp + 8, 4, 0xe2a00000);
+ /* nop */
+ write_memory_unsigned_integer (sp + 12, 4, 0x08000240);
+
+ regcache_cooked_write_unsigned (current_regcache, 21, funcaddr);
+ regcache_cooked_write_unsigned (current_regcache, 22, sp);
+ }
+
+ /* We set the breakpoint address and r31 to (close to) where the current
+ pc is; when __gcc_plt_call returns, it will restore pcsqh to the
+ current value based on this. The -4 is needed for frame unwinding
+ to work properly -- we need to land in a different function than
+ the current function. */
+ *bp_addr = (read_register (HPPA_PCOQ_HEAD_REGNUM) & ~3) - 4;
+ regcache_cooked_write_unsigned (current_regcache, 31, *bp_addr);
+
+ /* Continue from __gcc_plt_call. */
+ *real_pc = SYMBOL_VALUE (sym);
+ }
+ else
+ {
+ unsigned int gp;
+
+ /* Use __d_plt_call as a fallback; __d_plt_call expects to be called
+ with a plabel, so we need to build one. */
+
+ sym = lookup_minimal_symbol ("__d_plt_call", NULL, NULL);
+ if (sym == NULL)
+ error("Can't find an address for __d_plt_call or __gcc_plt_call "
+ "trampoline\nSuggest linking executable with -g or compiling "
+ "with gcc.");
+
+ gp = gdbarch_tdep (gdbarch)->find_global_pointer (funcaddr);
+ write_memory_unsigned_integer (sp, 4, funcaddr);
+ write_memory_unsigned_integer (sp + 4, 4, gp);
+
+ /* plabel is passed in r22 */
+ regcache_cooked_write_unsigned (current_regcache, 22, sp);
+ }
+
+ /* Pushed one stack frame, which has to be 64-byte aligned. */
+ sp += 64;
+
+ return sp;
+}
+
static void
hppa_hpux_inferior_created (struct target_ops *objfile, int from_tty)
{
hppa_hpux_in_solib_return_trampoline);
set_gdbarch_skip_trampoline_code (gdbarch, hppa_hpux_skip_trampoline_code);
+ set_gdbarch_push_dummy_code (gdbarch, hppa_hpux_push_dummy_code);
+ set_gdbarch_call_dummy_location (gdbarch, ON_STACK);
+
frame_unwind_append_sniffer (gdbarch, hppa_hpux_sigtramp_unwind_sniffer);
observer_attach_inferior_created (hppa_hpux_inferior_created);
struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
tdep->is_elf = 0;
+
+ tdep->find_global_pointer = hppa_hpux_som_find_global_pointer;
hppa_hpux_init_abi (info, gdbarch);
}
projects / deliverable / binutils-gdb.git / blobdiff