old-cross-binutils/gdb/irix5-nat.c
Peter Schauer 7621229598 Speed up GDB startup time by not demangling partial symbols.
* symfile.h (ADD_PSYMBOL_VT_TO_LIST),
	symfile.c (add_psymbol_to_list, add_psymbol_addr_to_list):
	No longer demangle partial symbols.
	* symtab.c (lookup_symbol, list_symbols): Handle mangled
	variables, e.g. C++ static members, via the minimal symbols.

	Handle reordered functions in an objfile, for Irix 5.2 shared
	libraries.
	* objfiles.h (OBJF_REORDERED):  New bit in the objfile flags,
	set if the functions in an objfile are reordered.
	* mdebugread.c (parse_partial_symbols):  Detect reordered
	functions in an objfile.
	* symtab.c (find_pc_psymtab, find_pc_symtab):  Use expensive
	lookup algorithm if the functions in the objfile are reordered.

	* xcoffexec.c (exec_close):  If the current target has a copy
	of the exec_ops sections, reflect the freeing of the sections
	in current_target.

	* valops.c (call_function_by_hand):  Use `sizeof dummy1', not
	`sizeof dummy', for constructing the call dummy code.

	* config/sparc/tm-sparc.h:  Add PARAMS declarations to all
	function declarations.
	* sparc-tdep.c (sparc_pop_frame):  Cast result of
	read_memory_integer to CORE_ADDR when passing it to PC_ADJUST.

	* irix5-nat.c (enable_break):  Set breakpoint at the entry point
	of the executable, to handle the case where main resides in a
	shared library.
	* irix5-nat.c (solib_create_inferior_hook):  Reset stop_soon_quietly
	after shared library symbol reading, to get rid of a warning from
	heuristic_proc_start if the startup code has no symbolic debug info.

	* breakpoint.h (struct breakpoint):  Add new fields language
	and input_radix, to enable breakpoint resetting with the
	proper language and radix.
	* breakpoint.c (set_raw_breakpoint):  Initialize them.
	(breakpoint_re_set_one):  Use them when resetting the breakpoint.
	(breakpoint_re_set):  Preserve current language and input_radix
	across breakpoint_re_set_one calls.

	* symtab.c (decode_line_1):  Do not build a canonical line
	specification for `*expr' line specifications.

	* breakpoint.h (bpstat_stop_status):  Fix prototype declaration.
1994-10-08 11:54:29 +00:00

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/* Native support for the SGI Iris running IRIX version 5, for GDB.
Copyright 1988, 1989, 1990, 1991, 1992, 1993, 1994
Free Software Foundation, Inc.
Contributed by Alessandro Forin(af@cs.cmu.edu) at CMU
and by Per Bothner(bothner@cs.wisc.edu) at U.Wisconsin.
Implemented for Irix 4.x by Garrett A. Wollman.
Modified for Irix 5.x by Ian Lance Taylor.
This file is part of GDB.
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 2 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, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
#include "defs.h"
#include "inferior.h"
#include "gdbcore.h"
#include "target.h"
#include <sys/time.h>
#include <sys/procfs.h>
#include <setjmp.h> /* For JB_XXX. */
/* Size of elements in jmpbuf */
#define JB_ELEMENT_SIZE 4
/*
* See the comment in m68k-tdep.c regarding the utility of these functions.
*
* These definitions are from the MIPS SVR4 ABI, so they may work for
* any MIPS SVR4 target.
*/
void
supply_gregset (gregsetp)
gregset_t *gregsetp;
{
register int regi;
register greg_t *regp = &(*gregsetp)[0];
for(regi = 0; regi <= CTX_RA; regi++)
supply_register (regi, (char *)(regp + regi));
supply_register (PC_REGNUM, (char *)(regp + CTX_EPC));
supply_register (HI_REGNUM, (char *)(regp + CTX_MDHI));
supply_register (LO_REGNUM, (char *)(regp + CTX_MDLO));
supply_register (CAUSE_REGNUM, (char *)(regp + CTX_CAUSE));
}
void
fill_gregset (gregsetp, regno)
gregset_t *gregsetp;
int regno;
{
int regi;
register greg_t *regp = &(*gregsetp)[0];
for (regi = 0; regi <= CTX_RA; regi++)
if ((regno == -1) || (regno == regi))
*(regp + regi) = *(greg_t *) &registers[REGISTER_BYTE (regi)];
if ((regno == -1) || (regno == PC_REGNUM))
*(regp + CTX_EPC) = *(greg_t *) &registers[REGISTER_BYTE (PC_REGNUM)];
if ((regno == -1) || (regno == CAUSE_REGNUM))
*(regp + CTX_CAUSE) = *(greg_t *) &registers[REGISTER_BYTE (PS_REGNUM)];
if ((regno == -1) || (regno == HI_REGNUM))
*(regp + CTX_MDHI) = *(greg_t *) &registers[REGISTER_BYTE (HI_REGNUM)];
if ((regno == -1) || (regno == LO_REGNUM))
*(regp + CTX_MDLO) = *(greg_t *) &registers[REGISTER_BYTE (LO_REGNUM)];
}
/*
* Now we do the same thing for floating-point registers.
* We don't bother to condition on FP0_REGNUM since any
* reasonable MIPS configuration has an R3010 in it.
*
* Again, see the comments in m68k-tdep.c.
*/
void
supply_fpregset (fpregsetp)
fpregset_t *fpregsetp;
{
register int regi;
for (regi = 0; regi < 32; regi++)
supply_register (FP0_REGNUM + regi,
(char *)&fpregsetp->fp_r.fp_regs[regi]);
supply_register (FCRCS_REGNUM, (char *)&fpregsetp->fp_csr);
/* FIXME: how can we supply FCRIR_REGNUM? SGI doesn't tell us. */
}
void
fill_fpregset (fpregsetp, regno)
fpregset_t *fpregsetp;
int regno;
{
int regi;
char *from, *to;
for (regi = FP0_REGNUM; regi < FP0_REGNUM + 32; regi++)
{
if ((regno == -1) || (regno == regi))
{
from = (char *) &registers[REGISTER_BYTE (regi)];
to = (char *) &(fpregsetp->fp_r.fp_regs[regi - FP0_REGNUM]);
memcpy(to, from, REGISTER_RAW_SIZE (regi));
}
}
if ((regno == -1) || (regno == FCRCS_REGNUM))
fpregsetp->fp_csr = *(unsigned *) &registers[REGISTER_BYTE(FCRCS_REGNUM)];
}
/* Figure out where the longjmp will land.
We expect the first arg to be a pointer to the jmp_buf structure from which
we extract the pc (JB_PC) that we will land at. The pc is copied into PC.
This routine returns true on success. */
int
get_longjmp_target (pc)
CORE_ADDR *pc;
{
char buf[TARGET_PTR_BIT / TARGET_CHAR_BIT];
CORE_ADDR jb_addr;
jb_addr = read_register (A0_REGNUM);
if (target_read_memory (jb_addr + JB_PC * JB_ELEMENT_SIZE, buf,
TARGET_PTR_BIT / TARGET_CHAR_BIT))
return 0;
*pc = extract_address (buf, TARGET_PTR_BIT / TARGET_CHAR_BIT);
return 1;
}
void
fetch_core_registers (core_reg_sect, core_reg_size, which, reg_addr)
char *core_reg_sect;
unsigned core_reg_size;
int which; /* Unused */
unsigned int reg_addr; /* Unused */
{
if (core_reg_size != REGISTER_BYTES)
{
warning ("wrong size gregset struct in core file");
return;
}
memcpy ((char *)registers, core_reg_sect, core_reg_size);
}
/* Irix 5 uses what appears to be a unique form of shared library
support. This is a copy of solib.c modified for Irix 5. */
#include <sys/types.h>
#include <signal.h>
#include <string.h>
#include <sys/param.h>
#include <fcntl.h>
/* <obj.h> includes <sym.h> and <symconst.h>, which causes conflicts
with our versions of those files included by tm-mips.h. Prevent
<obj.h> from including them with some appropriate defines. */
#define __SYM_H__
#define __SYMCONST_H__
#include <obj.h>
#include "symtab.h"
#include "bfd.h"
#include "symfile.h"
#include "objfiles.h"
#include "command.h"
#include "frame.h"
#include "regex.h"
#include "inferior.h"
#include "language.h"
/* The symbol which starts off the list of shared libraries. */
#define DEBUG_BASE "__rld_obj_head"
/* How to get the loaded address of a shared library. */
#define LM_ADDR(so) ((so)->lm.o_praw)
char shadow_contents[BREAKPOINT_MAX]; /* Stash old bkpt addr contents */
struct so_list {
struct so_list *next; /* next structure in linked list */
struct obj_list ll;
struct obj lm; /* copy of link map from inferior */
struct obj_list *lladdr; /* addr in inferior lm was read from */
CORE_ADDR lmend; /* upper addr bound of mapped object */
char symbols_loaded; /* flag: symbols read in yet? */
char from_tty; /* flag: print msgs? */
struct objfile *objfile; /* objfile for loaded lib */
struct section_table *sections;
struct section_table *sections_end;
struct section_table *textsection;
bfd *abfd;
};
static struct so_list *so_list_head; /* List of known shared objects */
static CORE_ADDR debug_base; /* Base of dynamic linker structures */
static CORE_ADDR breakpoint_addr; /* Address where end bkpt is set */
/* Local function prototypes */
static void
sharedlibrary_command PARAMS ((char *, int));
static int
enable_break PARAMS ((void));
static int
disable_break PARAMS ((void));
static void
info_sharedlibrary_command PARAMS ((char *, int));
static int
symbol_add_stub PARAMS ((char *));
static struct so_list *
find_solib PARAMS ((struct so_list *));
static struct obj_list *
first_link_map_member PARAMS ((void));
static CORE_ADDR
locate_base PARAMS ((void));
static void
solib_map_sections PARAMS ((struct so_list *));
/*
LOCAL FUNCTION
solib_map_sections -- open bfd and build sections for shared lib
SYNOPSIS
static void solib_map_sections (struct so_list *so)
DESCRIPTION
Given a pointer to one of the shared objects in our list
of mapped objects, use the recorded name to open a bfd
descriptor for the object, build a section table, and then
relocate all the section addresses by the base address at
which the shared object was mapped.
FIXMES
In most (all?) cases the shared object file name recorded in the
dynamic linkage tables will be a fully qualified pathname. For
cases where it isn't, do we really mimic the systems search
mechanism correctly in the below code (particularly the tilde
expansion stuff?).
*/
static void
solib_map_sections (so)
struct so_list *so;
{
char *filename;
char *scratch_pathname;
int scratch_chan;
struct section_table *p;
struct cleanup *old_chain;
bfd *abfd;
CORE_ADDR offset;
filename = tilde_expand (so -> lm.o_path);
old_chain = make_cleanup (free, filename);
scratch_chan = openp (getenv ("PATH"), 1, filename, O_RDONLY, 0,
&scratch_pathname);
if (scratch_chan < 0)
{
scratch_chan = openp (getenv ("LD_LIBRARY_PATH"), 1, filename,
O_RDONLY, 0, &scratch_pathname);
}
if (scratch_chan < 0)
{
perror_with_name (filename);
}
/* Leave scratch_pathname allocated. abfd->name will point to it. */
abfd = bfd_fdopenr (scratch_pathname, gnutarget, scratch_chan);
if (!abfd)
{
close (scratch_chan);
error ("Could not open `%s' as an executable file: %s",
scratch_pathname, bfd_errmsg (bfd_get_error ()));
}
/* Leave bfd open, core_xfer_memory and "info files" need it. */
so -> abfd = abfd;
abfd -> cacheable = true;
if (!bfd_check_format (abfd, bfd_object))
{
error ("\"%s\": not in executable format: %s.",
scratch_pathname, bfd_errmsg (bfd_get_error ()));
}
if (build_section_table (abfd, &so -> sections, &so -> sections_end))
{
error ("Can't find the file sections in `%s': %s",
bfd_get_filename (exec_bfd), bfd_errmsg (bfd_get_error ()));
}
/* Irix 5 shared objects are pre-linked to particular addresses
although the dynamic linker may have to relocate them if the
address ranges of the libraries used by the main program clash.
The offset is the difference between the address where the object
is mapped and the binding address of the shared library. */
offset = (CORE_ADDR) LM_ADDR (so) - so -> lm.o_base_address;
for (p = so -> sections; p < so -> sections_end; p++)
{
/* Relocate the section binding addresses as recorded in the shared
object's file by the offset to get the address to which the
object was actually mapped. */
p -> addr += offset;
p -> endaddr += offset;
so -> lmend = (CORE_ADDR) max (p -> endaddr, so -> lmend);
if (STREQ (p -> the_bfd_section -> name, ".text"))
{
so -> textsection = p;
}
}
/* Free the file names, close the file now. */
do_cleanups (old_chain);
}
/*
LOCAL FUNCTION
locate_base -- locate the base address of dynamic linker structs
SYNOPSIS
CORE_ADDR locate_base (void)
DESCRIPTION
For both the SunOS and SVR4 shared library implementations, if the
inferior executable has been linked dynamically, there is a single
address somewhere in the inferior's data space which is the key to
locating all of the dynamic linker's runtime structures. This
address is the value of the symbol defined by the macro DEBUG_BASE.
The job of this function is to find and return that address, or to
return 0 if there is no such address (the executable is statically
linked for example).
For SunOS, the job is almost trivial, since the dynamic linker and
all of it's structures are statically linked to the executable at
link time. Thus the symbol for the address we are looking for has
already been added to the minimal symbol table for the executable's
objfile at the time the symbol file's symbols were read, and all we
have to do is look it up there. Note that we explicitly do NOT want
to find the copies in the shared library.
The SVR4 version is much more complicated because the dynamic linker
and it's structures are located in the shared C library, which gets
run as the executable's "interpreter" by the kernel. We have to go
to a lot more work to discover the address of DEBUG_BASE. Because
of this complexity, we cache the value we find and return that value
on subsequent invocations. Note there is no copy in the executable
symbol tables.
Irix 5 is basically like SunOS.
Note that we can assume nothing about the process state at the time
we need to find this address. We may be stopped on the first instruc-
tion of the interpreter (C shared library), the first instruction of
the executable itself, or somewhere else entirely (if we attached
to the process for example).
*/
static CORE_ADDR
locate_base ()
{
struct minimal_symbol *msymbol;
CORE_ADDR address = 0;
msymbol = lookup_minimal_symbol (DEBUG_BASE, symfile_objfile);
if ((msymbol != NULL) && (SYMBOL_VALUE_ADDRESS (msymbol) != 0))
{
address = SYMBOL_VALUE_ADDRESS (msymbol);
}
return (address);
}
/*
LOCAL FUNCTION
first_link_map_member -- locate first member in dynamic linker's map
SYNOPSIS
static struct link_map *first_link_map_member (void)
DESCRIPTION
Read in a copy of the first member in the inferior's dynamic
link map from the inferior's dynamic linker structures, and return
a pointer to the copy in our address space.
*/
static struct obj_list *
first_link_map_member ()
{
struct obj_list *lm;
struct obj_list s;
read_memory (debug_base, (char *) &lm, sizeof (struct obj_list *));
if (lm == NULL)
return NULL;
/* The first entry in the list is the object file we are debugging,
so skip it. */
read_memory ((CORE_ADDR) lm, (char *) &s, sizeof (struct obj_list));
return s.next;
}
/*
LOCAL FUNCTION
find_solib -- step through list of shared objects
SYNOPSIS
struct so_list *find_solib (struct so_list *so_list_ptr)
DESCRIPTION
This module contains the routine which finds the names of any
loaded "images" in the current process. The argument in must be
NULL on the first call, and then the returned value must be passed
in on subsequent calls. This provides the capability to "step" down
the list of loaded objects. On the last object, a NULL value is
returned.
*/
static struct so_list *
find_solib (so_list_ptr)
struct so_list *so_list_ptr; /* Last lm or NULL for first one */
{
struct so_list *so_list_next = NULL;
struct obj_list *lm = NULL;
struct so_list *new;
if (so_list_ptr == NULL)
{
/* We are setting up for a new scan through the loaded images. */
if ((so_list_next = so_list_head) == NULL)
{
/* We have not already read in the dynamic linking structures
from the inferior, lookup the address of the base structure. */
debug_base = locate_base ();
if (debug_base != 0)
{
/* Read the base structure in and find the address of the first
link map list member. */
lm = first_link_map_member ();
}
}
}
else
{
/* We have been called before, and are in the process of walking
the shared library list. Advance to the next shared object. */
if ((lm = so_list_ptr->ll.next) == NULL)
{
/* We have hit the end of the list, so check to see if any were
added, but be quiet if we can't read from the target any more. */
int status = target_read_memory ((CORE_ADDR) so_list_ptr -> lladdr,
(char *) &(so_list_ptr -> ll),
sizeof (struct obj_list));
if (status == 0)
{
lm = so_list_ptr->ll.next;
}
else
{
lm = NULL;
}
}
so_list_next = so_list_ptr -> next;
}
if ((so_list_next == NULL) && (lm != NULL))
{
int errcode;
char *buffer;
/* Get next link map structure from inferior image and build a local
abbreviated load_map structure */
new = (struct so_list *) xmalloc (sizeof (struct so_list));
memset ((char *) new, 0, sizeof (struct so_list));
new -> lladdr = lm;
/* Add the new node as the next node in the list, or as the root
node if this is the first one. */
if (so_list_ptr != NULL)
{
so_list_ptr -> next = new;
}
else
{
so_list_head = new;
}
so_list_next = new;
read_memory ((CORE_ADDR) lm, (char *) &(new -> ll),
sizeof (struct obj_list));
read_memory ((CORE_ADDR) new->ll.data, (char *) &(new -> lm),
sizeof (struct obj));
target_read_string ((CORE_ADDR)new->lm.o_path, &buffer,
INT_MAX, &errcode);
if (errcode != 0)
memory_error (errcode, (CORE_ADDR)new->lm.o_path);
new->lm.o_path = buffer;
solib_map_sections (new);
}
return (so_list_next);
}
/* A small stub to get us past the arg-passing pinhole of catch_errors. */
static int
symbol_add_stub (arg)
char *arg;
{
register struct so_list *so = (struct so_list *) arg; /* catch_errs bogon */
so -> objfile = symbol_file_add (so -> lm.o_path, so -> from_tty,
(unsigned int) so -> textsection -> addr,
0, 0, 0);
return (1);
}
/*
GLOBAL FUNCTION
solib_add -- add a shared library file to the symtab and section list
SYNOPSIS
void solib_add (char *arg_string, int from_tty,
struct target_ops *target)
DESCRIPTION
*/
void
solib_add (arg_string, from_tty, target)
char *arg_string;
int from_tty;
struct target_ops *target;
{
register struct so_list *so = NULL; /* link map state variable */
/* Last shared library that we read. */
struct so_list *so_last = NULL;
char *re_err;
int count;
int old;
if ((re_err = re_comp (arg_string ? arg_string : ".")) != NULL)
{
error ("Invalid regexp: %s", re_err);
}
/* Add the shared library sections to the section table of the
specified target, if any. */
if (target)
{
/* Count how many new section_table entries there are. */
so = NULL;
count = 0;
while ((so = find_solib (so)) != NULL)
{
if (so -> lm.o_path[0])
{
count += so -> sections_end - so -> sections;
}
}
if (count)
{
/* Reallocate the target's section table including the new size. */
if (target -> to_sections)
{
old = target -> to_sections_end - target -> to_sections;
target -> to_sections = (struct section_table *)
xrealloc ((char *)target -> to_sections,
(sizeof (struct section_table)) * (count + old));
}
else
{
old = 0;
target -> to_sections = (struct section_table *)
xmalloc ((sizeof (struct section_table)) * count);
}
target -> to_sections_end = target -> to_sections + (count + old);
/* Add these section table entries to the target's table. */
while ((so = find_solib (so)) != NULL)
{
if (so -> lm.o_path[0])
{
count = so -> sections_end - so -> sections;
memcpy ((char *) (target -> to_sections + old),
so -> sections,
(sizeof (struct section_table)) * count);
old += count;
}
}
}
}
/* Now add the symbol files. */
while ((so = find_solib (so)) != NULL)
{
if (so -> lm.o_path[0] && re_exec (so -> lm.o_path))
{
so -> from_tty = from_tty;
if (so -> symbols_loaded)
{
if (from_tty)
{
printf_unfiltered ("Symbols already loaded for %s\n", so -> lm.o_path);
}
}
else if (catch_errors
(symbol_add_stub, (char *) so,
"Error while reading shared library symbols:\n",
RETURN_MASK_ALL))
{
so_last = so;
so -> symbols_loaded = 1;
}
}
}
/* Getting new symbols may change our opinion about what is
frameless. */
if (so_last)
reinit_frame_cache ();
}
/*
LOCAL FUNCTION
info_sharedlibrary_command -- code for "info sharedlibrary"
SYNOPSIS
static void info_sharedlibrary_command ()
DESCRIPTION
Walk through the shared library list and print information
about each attached library.
*/
static void
info_sharedlibrary_command (ignore, from_tty)
char *ignore;
int from_tty;
{
register struct so_list *so = NULL; /* link map state variable */
int header_done = 0;
if (exec_bfd == NULL)
{
printf_unfiltered ("No exec file.\n");
return;
}
while ((so = find_solib (so)) != NULL)
{
if (so -> lm.o_path[0])
{
if (!header_done)
{
printf_unfiltered("%-12s%-12s%-12s%s\n", "From", "To", "Syms Read",
"Shared Object Library");
header_done++;
}
printf_unfiltered ("%-12s",
local_hex_string_custom ((unsigned long) LM_ADDR (so),
"08l"));
printf_unfiltered ("%-12s",
local_hex_string_custom ((unsigned long) so -> lmend,
"08l"));
printf_unfiltered ("%-12s", so -> symbols_loaded ? "Yes" : "No");
printf_unfiltered ("%s\n", so -> lm.o_path);
}
}
if (so_list_head == NULL)
{
printf_unfiltered ("No shared libraries loaded at this time.\n");
}
}
/*
GLOBAL FUNCTION
solib_address -- check to see if an address is in a shared lib
SYNOPSIS
int solib_address (CORE_ADDR address)
DESCRIPTION
Provides a hook for other gdb routines to discover whether or
not a particular address is within the mapped address space of
a shared library. Any address between the base mapping address
and the first address beyond the end of the last mapping, is
considered to be within the shared library address space, for
our purposes.
For example, this routine is called at one point to disable
breakpoints which are in shared libraries that are not currently
mapped in.
*/
int
solib_address (address)
CORE_ADDR address;
{
register struct so_list *so = 0; /* link map state variable */
while ((so = find_solib (so)) != NULL)
{
if (so -> lm.o_path[0])
{
if ((address >= (CORE_ADDR) LM_ADDR (so)) &&
(address < (CORE_ADDR) so -> lmend))
{
return (1);
}
}
}
return (0);
}
/* Called by free_all_symtabs */
void
clear_solib()
{
struct so_list *next;
char *bfd_filename;
while (so_list_head)
{
if (so_list_head -> sections)
{
free ((PTR)so_list_head -> sections);
}
if (so_list_head -> abfd)
{
bfd_filename = bfd_get_filename (so_list_head -> abfd);
bfd_close (so_list_head -> abfd);
}
else
/* This happens for the executable on SVR4. */
bfd_filename = NULL;
next = so_list_head -> next;
if (bfd_filename)
free ((PTR)bfd_filename);
free (so_list_head->lm.o_path);
free ((PTR)so_list_head);
so_list_head = next;
}
debug_base = 0;
}
/*
LOCAL FUNCTION
disable_break -- remove the "mapping changed" breakpoint
SYNOPSIS
static int disable_break ()
DESCRIPTION
Removes the breakpoint that gets hit when the dynamic linker
completes a mapping change.
*/
static int
disable_break ()
{
int status = 1;
/* Note that breakpoint address and original contents are in our address
space, so we just need to write the original contents back. */
if (memory_remove_breakpoint (breakpoint_addr, shadow_contents) != 0)
{
status = 0;
}
/* For the SVR4 version, we always know the breakpoint address. For the
SunOS version we don't know it until the above code is executed.
Grumble if we are stopped anywhere besides the breakpoint address. */
if (stop_pc != breakpoint_addr)
{
warning ("stopped at unknown breakpoint while handling shared libraries");
}
return (status);
}
/*
LOCAL FUNCTION
enable_break -- arrange for dynamic linker to hit breakpoint
SYNOPSIS
int enable_break (void)
DESCRIPTION
This functions inserts a breakpoint at the entry point of the
main executable, where all shared libraries are mapped in.
*/
static int
enable_break ()
{
if (symfile_objfile != NULL
&& target_insert_breakpoint (symfile_objfile->ei.entry_point,
shadow_contents) == 0)
{
breakpoint_addr = symfile_objfile->ei.entry_point;
return 1;
}
return 0;
}
/*
GLOBAL FUNCTION
solib_create_inferior_hook -- shared library startup support
SYNOPSIS
void solib_create_inferior_hook()
DESCRIPTION
When gdb starts up the inferior, it nurses it along (through the
shell) until it is ready to execute it's first instruction. At this
point, this function gets called via expansion of the macro
SOLIB_CREATE_INFERIOR_HOOK.
For SunOS executables, this first instruction is typically the
one at "_start", or a similar text label, regardless of whether
the executable is statically or dynamically linked. The runtime
startup code takes care of dynamically linking in any shared
libraries, once gdb allows the inferior to continue.
For SVR4 executables, this first instruction is either the first
instruction in the dynamic linker (for dynamically linked
executables) or the instruction at "start" for statically linked
executables. For dynamically linked executables, the system
first exec's /lib/libc.so.N, which contains the dynamic linker,
and starts it running. The dynamic linker maps in any needed
shared libraries, maps in the actual user executable, and then
jumps to "start" in the user executable.
For both SunOS shared libraries, and SVR4 shared libraries, we
can arrange to cooperate with the dynamic linker to discover the
names of shared libraries that are dynamically linked, and the
base addresses to which they are linked.
This function is responsible for discovering those names and
addresses, and saving sufficient information about them to allow
their symbols to be read at a later time.
FIXME
Between enable_break() and disable_break(), this code does not
properly handle hitting breakpoints which the user might have
set in the startup code or in the dynamic linker itself. Proper
handling will probably have to wait until the implementation is
changed to use the "breakpoint handler function" method.
Also, what if child has exit()ed? Must exit loop somehow.
*/
void
solib_create_inferior_hook()
{
if (!enable_break ())
{
warning ("shared library handler failed to enable breakpoint");
return;
}
/* Now run the target. It will eventually hit the breakpoint, at
which point all of the libraries will have been mapped in and we
can go groveling around in the dynamic linker structures to find
out what we need to know about them. */
clear_proceed_status ();
stop_soon_quietly = 1;
stop_signal = 0;
do
{
target_resume (-1, 0, stop_signal);
wait_for_inferior ();
}
while (stop_signal != SIGTRAP);
/* We are now either at the "mapping complete" breakpoint (or somewhere
else, a condition we aren't prepared to deal with anyway), so adjust
the PC as necessary after a breakpoint, disable the breakpoint, and
add any shared libraries that were mapped in. */
if (DECR_PC_AFTER_BREAK)
{
stop_pc -= DECR_PC_AFTER_BREAK;
write_register (PC_REGNUM, stop_pc);
}
if (!disable_break ())
{
warning ("shared library handler failed to disable breakpoint");
}
/* solib_add will call reinit_frame_cache.
But we are stopped in the startup code and we might not have symbols
for the startup code, so heuristic_proc_start could be called
and will put out an annoying warning.
Delaying the resetting of stop_soon_quietly until after symbol loading
suppresses the warning. */
solib_add ((char *) 0, 0, (struct target_ops *) 0);
stop_soon_quietly = 0;
}
/*
LOCAL FUNCTION
sharedlibrary_command -- handle command to explicitly add library
SYNOPSIS
static void sharedlibrary_command (char *args, int from_tty)
DESCRIPTION
*/
static void
sharedlibrary_command (args, from_tty)
char *args;
int from_tty;
{
dont_repeat ();
solib_add (args, from_tty, (struct target_ops *) 0);
}
void
_initialize_solib()
{
add_com ("sharedlibrary", class_files, sharedlibrary_command,
"Load shared object library symbols for files matching REGEXP.");
add_info ("sharedlibrary", info_sharedlibrary_command,
"Status of loaded shared object libraries.");
}