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binutils-gdb/gdb/frame.c

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/* Cache and manage frames for GDB, the GNU debugger.
Copyright 1986, 1987, 1989, 1991, 1994, 1995, 1996, 1998, 2000,
2001, 2002 Free Software Foundation, Inc.
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., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include "defs.h"
#include "frame.h"
#include "target.h"
#include "value.h"
#include "inferior.h" /* for inferior_ptid */
#include "regcache.h"
#include "gdb_assert.h"
#include "gdb_string.h"
#include "builtin-regs.h"
#include "gdb_obstack.h"
#include "dummy-frame.h"
#include "gdbcore.h"
#include "annotate.h"
#include "language.h"
/* Return a frame uniq ID that can be used to, later, re-find the
frame. */
struct frame_id
get_frame_id (struct frame_info *fi)
{
if (fi == NULL)
{
return null_frame_id;
}
else
{
struct frame_id id;
id.base = fi->frame;
id.pc = fi->pc;
return id;
}
}
const struct frame_id null_frame_id; /* All zeros. */
struct frame_id
frame_id_build (CORE_ADDR base, CORE_ADDR func_or_pc)
{
struct frame_id id;
id.base = base;
id.pc = func_or_pc;
return id;
}
int
frame_id_p (struct frame_id l)
{
/* The .func can be NULL but the .base cannot. */
return (l.base != 0);
}
int
frame_id_eq (struct frame_id l, struct frame_id r)
{
/* If .base is different, the frames are different. */
if (l.base != r.base)
return 0;
/* Add a test to check that the frame ID's are for the same function
here. */
return 1;
}
int
frame_id_inner (struct frame_id l, struct frame_id r)
{
/* Only return non-zero when strictly inner than. Note that, per
comment in "frame.h", there is some fuzz here. Frameless
functions are not strictly inner than (same .base but different
.func). */
return INNER_THAN (l.base, r.base);
}
struct frame_info *
frame_find_by_id (struct frame_id id)
{
struct frame_info *frame;
/* ZERO denotes the null frame, let the caller decide what to do
about it. Should it instead return get_current_frame()? */
if (!frame_id_p (id))
return NULL;
for (frame = get_current_frame ();
frame != NULL;
frame = get_prev_frame (frame))
{
struct frame_id this = get_frame_id (frame);
if (frame_id_eq (id, this))
/* An exact match. */
return frame;
if (frame_id_inner (id, this))
/* Gone to far. */
return NULL;
/* Either, we're not yet gone far enough out along the frame
chain (inner(this,id), or we're comparing frameless functions
(same .base, different .func, no test available). Struggle
on until we've definitly gone to far. */
}
return NULL;
}
CORE_ADDR
frame_pc_unwind (struct frame_info *frame)
{
if (!frame->pc_unwind_cache_p)
{
frame->pc_unwind_cache = frame->pc_unwind (frame, &frame->unwind_cache);
frame->pc_unwind_cache_p = 1;
}
return frame->pc_unwind_cache;
}
struct frame_id
frame_id_unwind (struct frame_info *frame)
{
if (!frame->id_unwind_cache_p)
{
frame->id_unwind_cache =
frame->id_unwind (frame, &frame->unwind_cache);
frame->id_unwind_cache_p = 1;
}
return frame->id_unwind_cache;
}
void
frame_register_unwind (struct frame_info *frame, int regnum,
int *optimizedp, enum lval_type *lvalp,
CORE_ADDR *addrp, int *realnump, void *bufferp)
{
struct frame_unwind_cache *cache;
/* Require all but BUFFERP to be valid. A NULL BUFFERP indicates
that the value proper does not need to be fetched. */
gdb_assert (optimizedp != NULL);
gdb_assert (lvalp != NULL);
gdb_assert (addrp != NULL);
gdb_assert (realnump != NULL);
/* gdb_assert (bufferp != NULL); */
/* NOTE: cagney/2002-04-14: It would be nice if, instead of a
special case, there was always an inner frame dedicated to the
hardware registers. Unfortunatly, there is too much unwind code
around that looks up/down the frame chain while making the
assumption that each frame level is using the same unwind code. */
if (frame == NULL)
{
/* We're in the inner-most frame, get the value direct from the
register cache. */
*optimizedp = 0;
*lvalp = lval_register;
/* ULGH! Code uses the offset into the raw register byte array
as a way of identifying a register. */
*addrp = REGISTER_BYTE (regnum);
/* Should this code test ``register_cached (regnum) < 0'' and do
something like set realnum to -1 when the register isn't
available? */
*realnump = regnum;
if (bufferp)
deprecated_read_register_gen (regnum, bufferp);
return;
}
/* Ask this frame to unwind its register. */
frame->register_unwind (frame, &frame->unwind_cache, regnum,
optimizedp, lvalp, addrp, realnump, bufferp);
}
void
frame_register (struct frame_info *frame, int regnum,
int *optimizedp, enum lval_type *lvalp,
CORE_ADDR *addrp, int *realnump, void *bufferp)
{
/* Require all but BUFFERP to be valid. A NULL BUFFERP indicates
that the value proper does not need to be fetched. */
gdb_assert (optimizedp != NULL);
gdb_assert (lvalp != NULL);
gdb_assert (addrp != NULL);
gdb_assert (realnump != NULL);
/* gdb_assert (bufferp != NULL); */
/* Ulgh! Old code that, for lval_register, sets ADDRP to the offset
of the register in the register cache. It should instead return
the REGNUM corresponding to that register. Translate the . */
if (GET_SAVED_REGISTER_P ())
{
GET_SAVED_REGISTER (bufferp, optimizedp, addrp, frame, regnum, lvalp);
/* Compute the REALNUM if the caller wants it. */
if (*lvalp == lval_register)
{
int regnum;
for (regnum = 0; regnum < NUM_REGS + NUM_PSEUDO_REGS; regnum++)
{
if (*addrp == register_offset_hack (current_gdbarch, regnum))
{
*realnump = regnum;
return;
}
}
internal_error (__FILE__, __LINE__,
"Failed to compute the register number corresponding"
" to 0x%s", paddr_d (*addrp));
}
*realnump = -1;
return;
}
/* Reached the the bottom (youngest, inner most) of the frame chain
(youngest, inner most) frame, go direct to the hardware register
cache (do not pass go, do not try to cache the value, ...). The
unwound value would have been cached in frame->next but that
doesn't exist. This doesn't matter as the hardware register
cache is stopping any unnecessary accesses to the target. */
/* NOTE: cagney/2002-04-14: It would be nice if, instead of a
special case, there was always an inner frame dedicated to the
hardware registers. Unfortunatly, there is too much unwind code
around that looks up/down the frame chain while making the
assumption that each frame level is using the same unwind code. */
if (frame == NULL)
frame_register_unwind (NULL, regnum, optimizedp, lvalp, addrp, realnump,
bufferp);
else
frame_register_unwind (frame->next, regnum, optimizedp, lvalp, addrp,
realnump, bufferp);
}
void
frame_unwind_signed_register (struct frame_info *frame, int regnum,
LONGEST *val)
{
int optimized;
CORE_ADDR addr;
int realnum;
enum lval_type lval;
void *buf = alloca (MAX_REGISTER_RAW_SIZE);
frame_register_unwind (frame, regnum, &optimized, &lval, &addr,
&realnum, buf);
(*val) = extract_signed_integer (buf, REGISTER_VIRTUAL_SIZE (regnum));
}
void
frame_unwind_unsigned_register (struct frame_info *frame, int regnum,
ULONGEST *val)
{
int optimized;
CORE_ADDR addr;
int realnum;
enum lval_type lval;
void *buf = alloca (MAX_REGISTER_RAW_SIZE);
frame_register_unwind (frame, regnum, &optimized, &lval, &addr,
&realnum, buf);
(*val) = extract_unsigned_integer (buf, REGISTER_VIRTUAL_SIZE (regnum));
}
void
frame_read_unsigned_register (struct frame_info *frame, int regnum,
ULONGEST *val)
{
/* NOTE: cagney/2002-10-31: There is a bit of dogma here - there is
always a frame. Both this, and the equivalent
frame_read_signed_register() function, can only be called with a
valid frame. If, for some reason, this function is called
without a frame then the problem isn't here, but rather in the
caller. It should of first created a frame and then passed that
in. */
/* NOTE: cagney/2002-10-31: As a side bar, keep in mind that the
``current_frame'' should not be treated as a special case. While
``get_next_frame (current_frame) == NULL'' currently holds, it
should, as far as possible, not be relied upon. In the future,
``get_next_frame (current_frame)'' may instead simply return a
normal frame object that simply always gets register values from
the register cache. Consequently, frame code should try to avoid
tests like ``if get_next_frame() == NULL'' and instead just rely
on recursive frame calls (like the below code) when manipulating
a frame chain. */
gdb_assert (frame != NULL);
frame_unwind_unsigned_register (get_next_frame (frame), regnum, val);
}
void
frame_read_signed_register (struct frame_info *frame, int regnum,
LONGEST *val)
{
/* See note in frame_read_unsigned_register(). */
gdb_assert (frame != NULL);
frame_unwind_signed_register (get_next_frame (frame), regnum, val);
}
static void
generic_unwind_get_saved_register (char *raw_buffer,
int *optimizedp,
CORE_ADDR *addrp,
struct frame_info *frame,
int regnum,
enum lval_type *lvalp)
{
int optimizedx;
CORE_ADDR addrx;
int realnumx;
enum lval_type lvalx;
if (!target_has_registers)
error ("No registers.");
/* Keep things simple, ensure that all the pointers (except valuep)
are non NULL. */
if (optimizedp == NULL)
optimizedp = &optimizedx;
if (lvalp == NULL)
lvalp = &lvalx;
if (addrp == NULL)
addrp = &addrx;
/* Reached the the bottom (youngest, inner most) of the frame chain
(youngest, inner most) frame, go direct to the hardware register
cache (do not pass go, do not try to cache the value, ...). The
unwound value would have been cached in frame->next but that
doesn't exist. This doesn't matter as the hardware register
cache is stopping any unnecessary accesses to the target. */
/* NOTE: cagney/2002-04-14: It would be nice if, instead of a
special case, there was always an inner frame dedicated to the
hardware registers. Unfortunatly, there is too much unwind code
around that looks up/down the frame chain while making the
assumption that each frame level is using the same unwind code. */
if (frame == NULL)
frame_register_unwind (NULL, regnum, optimizedp, lvalp, addrp, &realnumx,
raw_buffer);
else
frame_register_unwind (frame->next, regnum, optimizedp, lvalp, addrp,
&realnumx, raw_buffer);
}
void
get_saved_register (char *raw_buffer,
int *optimized,
CORE_ADDR *addrp,
struct frame_info *frame,
int regnum,
enum lval_type *lval)
{
if (GET_SAVED_REGISTER_P ())
{
GET_SAVED_REGISTER (raw_buffer, optimized, addrp, frame, regnum, lval);
return;
}
generic_unwind_get_saved_register (raw_buffer, optimized, addrp, frame,
regnum, lval);
}
/* frame_register_read ()
Find and return the value of REGNUM for the specified stack frame.
The number of bytes copied is REGISTER_RAW_SIZE (REGNUM).
Returns 0 if the register value could not be found. */
int
frame_register_read (struct frame_info *frame, int regnum, void *myaddr)
{
int optimized;
enum lval_type lval;
CORE_ADDR addr;
int realnum;
frame_register (frame, regnum, &optimized, &lval, &addr, &realnum, myaddr);
/* FIXME: cagney/2002-05-15: This test, is just bogus.
It indicates that the target failed to supply a value for a
register because it was "not available" at this time. Problem
is, the target still has the register and so get saved_register()
may be returning a value saved on the stack. */
if (register_cached (regnum) < 0)
return 0; /* register value not available */
return !optimized;
}
/* Map between a frame register number and its name. A frame register
space is a superset of the cooked register space --- it also
includes builtin registers. */
int
frame_map_name_to_regnum (const char *name, int len)
{
int i;
/* Search register name space. */
for (i = 0; i < NUM_REGS + NUM_PSEUDO_REGS; i++)
if (REGISTER_NAME (i) && len == strlen (REGISTER_NAME (i))
&& strncmp (name, REGISTER_NAME (i), len) == 0)
{
return i;
}
/* Try builtin registers. */
i = builtin_reg_map_name_to_regnum (name, len);
if (i >= 0)
{
/* A builtin register doesn't fall into the architecture's
register range. */
gdb_assert (i >= NUM_REGS + NUM_PSEUDO_REGS);
return i;
}
return -1;
}
const char *
frame_map_regnum_to_name (int regnum)
{
if (regnum < 0)
return NULL;
if (regnum < NUM_REGS + NUM_PSEUDO_REGS)
return REGISTER_NAME (regnum);
return builtin_reg_map_regnum_to_name (regnum);
}
/* Info about the innermost stack frame (contents of FP register) */
static struct frame_info *current_frame;
/* Cache for frame addresses already read by gdb. Valid only while
inferior is stopped. Control variables for the frame cache should
be local to this module. */
static struct obstack frame_cache_obstack;
void *
frame_obstack_alloc (unsigned long size)
{
return obstack_alloc (&frame_cache_obstack, size);
}
CORE_ADDR *
frame_saved_regs_zalloc (struct frame_info *fi)
{
fi->saved_regs = (CORE_ADDR *)
frame_obstack_alloc (SIZEOF_FRAME_SAVED_REGS);
memset (fi->saved_regs, 0, SIZEOF_FRAME_SAVED_REGS);
return fi->saved_regs;
}
CORE_ADDR *
get_frame_saved_regs (struct frame_info *fi)
{
return fi->saved_regs;
}
/* Return the innermost (currently executing) stack frame. */
struct frame_info *
get_current_frame (void)
{
if (current_frame == NULL)
{
if (target_has_stack)
current_frame = create_new_frame (read_fp (), read_pc ());
else
error ("No stack.");
}
return current_frame;
}
/* The "selected" stack frame is used by default for local and arg
access. May be zero, for no selected frame. */
struct frame_info *deprecated_selected_frame;
/* Return the selected frame. Always non-null (unless there isn't an
inferior sufficient for creating a frame) in which case an error is
thrown. */
struct frame_info *
get_selected_frame (void)
{
if (deprecated_selected_frame == NULL)
/* Hey! Don't trust this. It should really be re-finding the
last selected frame of the currently selected thread. This,
though, is better than nothing. */
select_frame (get_current_frame ());
/* There is always a frame. */
gdb_assert (deprecated_selected_frame != NULL);
return deprecated_selected_frame;
}
/* Select frame FI (or NULL - to invalidate the current frame). */
void
select_frame (struct frame_info *fi)
{
register struct symtab *s;
deprecated_selected_frame = fi;
/* NOTE: cagney/2002-05-04: FI can be NULL. This occures when the
frame is being invalidated. */
if (selected_frame_level_changed_hook)
selected_frame_level_changed_hook (frame_relative_level (fi));
/* FIXME: kseitz/2002-08-28: It would be nice to call
selected_frame_level_changed_event right here, but due to limitations
in the current interfaces, we would end up flooding UIs with events
because select_frame is used extensively internally.
Once we have frame-parameterized frame (and frame-related) commands,
the event notification can be moved here, since this function will only
be called when the users selected frame is being changed. */
/* Ensure that symbols for this frame are read in. Also, determine the
source language of this frame, and switch to it if desired. */
if (fi)
{
s = find_pc_symtab (fi->pc);
if (s
&& s->language != current_language->la_language
&& s->language != language_unknown
&& language_mode == language_mode_auto)
{
set_language (s->language);
}
}
}
/* Return the register saved in the simplistic ``saved_regs'' cache.
If the value isn't here AND a value is needed, try the next inner
most frame. */
static void
frame_saved_regs_register_unwind (struct frame_info *frame, void **cache,
int regnum, int *optimizedp,
enum lval_type *lvalp, CORE_ADDR *addrp,
int *realnump, void *bufferp)
{
/* There is always a frame at this point. And THIS is the frame
we're interested in. */
gdb_assert (frame != NULL);
/* If we're using generic dummy frames, we'd better not be in a call
dummy. (generic_call_dummy_register_unwind ought to have been called
instead.) */
gdb_assert (!(DEPRECATED_USE_GENERIC_DUMMY_FRAMES
&& (get_frame_type (frame) == DUMMY_FRAME)));
/* Load the saved_regs register cache. */
if (frame->saved_regs == NULL)
FRAME_INIT_SAVED_REGS (frame);
if (frame->saved_regs != NULL
&& frame->saved_regs[regnum] != 0)
{
if (regnum == SP_REGNUM)
{
/* SP register treated specially. */
*optimizedp = 0;
*lvalp = not_lval;
*addrp = 0;
*realnump = -1;
if (bufferp != NULL)
store_address (bufferp, REGISTER_RAW_SIZE (regnum),
frame->saved_regs[regnum]);
}
else
{
/* Any other register is saved in memory, fetch it but cache
a local copy of its value. */
*optimizedp = 0;
*lvalp = lval_memory;
*addrp = frame->saved_regs[regnum];
*realnump = -1;
if (bufferp != NULL)
{
#if 1
/* Save each register value, as it is read in, in a
frame based cache. */
void **regs = (*cache);
if (regs == NULL)
{
int sizeof_cache = ((NUM_REGS + NUM_PSEUDO_REGS)
* sizeof (void *));
regs = frame_obstack_alloc (sizeof_cache);
memset (regs, 0, sizeof_cache);
(*cache) = regs;
}
if (regs[regnum] == NULL)
{
regs[regnum]
= frame_obstack_alloc (REGISTER_RAW_SIZE (regnum));
read_memory (frame->saved_regs[regnum], regs[regnum],
REGISTER_RAW_SIZE (regnum));
}
memcpy (bufferp, regs[regnum], REGISTER_RAW_SIZE (regnum));
#else
/* Read the value in from memory. */
read_memory (frame->saved_regs[regnum], bufferp,
REGISTER_RAW_SIZE (regnum));
#endif
}
}
return;
}
/* No luck, assume this and the next frame have the same register
value. If a value is needed, pass the request on down the chain;
otherwise just return an indication that the value is in the same
register as the next frame. */
if (bufferp == NULL)
{
*optimizedp = 0;
*lvalp = lval_register;
*addrp = 0;
*realnump = regnum;
}
else
{
frame_register_unwind (frame->next, regnum, optimizedp, lvalp, addrp,
realnump, bufferp);
}
}
static CORE_ADDR
frame_saved_regs_pc_unwind (struct frame_info *frame, void **cache)
{
return FRAME_SAVED_PC (frame);
}
static struct frame_id
frame_saved_regs_id_unwind (struct frame_info *next_frame, void **cache)
{
int fromleaf;
struct frame_id id;
if (next_frame->next == NULL)
/* FIXME: 2002-11-09: Frameless functions can occure anywhere in
the frame chain, not just the inner most frame! The generic,
per-architecture, frame code should handle this and the below
should simply be removed. */
fromleaf = FRAMELESS_FUNCTION_INVOCATION (next_frame);
else
fromleaf = 0;
if (fromleaf)
/* A frameless inner-most frame. The `FP' (which isn't an
architecture frame-pointer register!) of the caller is the same
as the callee. */
/* FIXME: 2002-11-09: There isn't any reason to special case this
edge condition. Instead the per-architecture code should hande
it locally. */
id.base = get_frame_base (next_frame);
else
{
/* Two macros defined in tm.h specify the machine-dependent
actions to be performed here.
First, get the frame's chain-pointer.
If that is zero, the frame is the outermost frame or a leaf
called by the outermost frame. This means that if start
calls main without a frame, we'll return 0 (which is fine
anyway).
Nope; there's a problem. This also returns when the current
routine is a leaf of main. This is unacceptable. We move
this to after the ffi test; I'd rather have backtraces from
start go curfluy than have an abort called from main not show
main. */
id.base = FRAME_CHAIN (next_frame);
/* FIXME: cagney/2002-06-08: There should be two tests here.
The first would check for a valid frame chain based on a user
selectable policy. The default being ``stop at main'' (as
implemented by generic_func_frame_chain_valid()). Other
policies would be available - stop at NULL, .... The second
test, if provided by the target architecture, would check for
more exotic cases - most target architectures wouldn't bother
with this second case. */
if (!FRAME_CHAIN_VALID (id.base, next_frame))
return null_frame_id;
}
if (id.base == 0)
return null_frame_id;
/* FIXME: cagney/2002-06-08: This should probably return the frame's
function and not the PC (a.k.a. resume address). */
id.pc = frame_pc_unwind (next_frame);
return id;
}
/* Function: get_saved_register
Find register number REGNUM relative to FRAME and put its (raw,
target format) contents in *RAW_BUFFER.
Set *OPTIMIZED if the variable was optimized out (and thus can't be
fetched). Note that this is never set to anything other than zero
in this implementation.
Set *LVAL to lval_memory, lval_register, or not_lval, depending on
whether the value was fetched from memory, from a register, or in a
strange and non-modifiable way (e.g. a frame pointer which was
calculated rather than fetched). We will use not_lval for values
fetched from generic dummy frames.
Set *ADDRP to the address, either in memory or as a REGISTER_BYTE
offset into the registers array. If the value is stored in a dummy
frame, set *ADDRP to zero.
To use this implementation, define a function called
"get_saved_register" in your target code, which simply passes all
of its arguments to this function.
The argument RAW_BUFFER must point to aligned memory. */
void
deprecated_generic_get_saved_register (char *raw_buffer, int *optimized,
CORE_ADDR *addrp,
struct frame_info *frame, int regnum,
enum lval_type *lval)
{
if (!target_has_registers)
error ("No registers.");
/* Normal systems don't optimize out things with register numbers. */
if (optimized != NULL)
*optimized = 0;
if (addrp) /* default assumption: not found in memory */
*addrp = 0;
/* Note: since the current frame's registers could only have been
saved by frames INTERIOR TO the current frame, we skip examining
the current frame itself: otherwise, we would be getting the
previous frame's registers which were saved by the current frame. */
while (frame && ((frame = frame->next) != NULL))
{
if (get_frame_type (frame) == DUMMY_FRAME)
{
if (lval) /* found it in a CALL_DUMMY frame */
*lval = not_lval;
if (raw_buffer)
/* FIXME: cagney/2002-06-26: This should be via the
gdbarch_register_read() method so that it, on the fly,
constructs either a raw or pseudo register from the raw
register cache. */
regcache_raw_read (generic_find_dummy_frame (frame->pc,
frame->frame),
regnum, raw_buffer);
return;
}
FRAME_INIT_SAVED_REGS (frame);
if (frame->saved_regs != NULL
&& frame->saved_regs[regnum] != 0)
{
if (lval) /* found it saved on the stack */
*lval = lval_memory;
if (regnum == SP_REGNUM)
{
if (raw_buffer) /* SP register treated specially */
store_address (raw_buffer, REGISTER_RAW_SIZE (regnum),
frame->saved_regs[regnum]);
}
else
{
if (addrp) /* any other register */
*addrp = frame->saved_regs[regnum];
if (raw_buffer)
read_memory (frame->saved_regs[regnum], raw_buffer,
REGISTER_RAW_SIZE (regnum));
}
return;
}
}
/* If we get thru the loop to this point, it means the register was
not saved in any frame. Return the actual live-register value. */
if (lval) /* found it in a live register */
*lval = lval_register;
if (addrp)
*addrp = REGISTER_BYTE (regnum);
if (raw_buffer)
deprecated_read_register_gen (regnum, raw_buffer);
}
/* Using the PC, select a mechanism for unwinding a frame returning
the previous frame. The register unwind function should, on
demand, initialize the ->context object. */
static void
set_unwind_by_pc (CORE_ADDR pc, CORE_ADDR fp,
frame_register_unwind_ftype **unwind_register,
frame_pc_unwind_ftype **unwind_pc,
frame_id_unwind_ftype **unwind_id)
{
if (!DEPRECATED_USE_GENERIC_DUMMY_FRAMES)
{
/* Still need to set this to something. The ``info frame'' code
calls this function to find out where the saved registers are.
Hopefully this is robust enough to stop any core dumps and
return vaguely correct values.. */
*unwind_register = frame_saved_regs_register_unwind;
*unwind_pc = frame_saved_regs_pc_unwind;
*unwind_id = frame_saved_regs_id_unwind;
}
else if (DEPRECATED_PC_IN_CALL_DUMMY_P ()
? DEPRECATED_PC_IN_CALL_DUMMY (pc, 0, 0)
: pc_in_dummy_frame (pc))
{
*unwind_register = dummy_frame_register_unwind;
*unwind_pc = dummy_frame_pc_unwind;
*unwind_id = dummy_frame_id_unwind;
}
else
{
*unwind_register = frame_saved_regs_register_unwind;
*unwind_pc = frame_saved_regs_pc_unwind;
*unwind_id = frame_saved_regs_id_unwind;
}
}
/* Create an arbitrary (i.e. address specified by user) or innermost frame.
Always returns a non-NULL value. */
struct frame_info *
create_new_frame (CORE_ADDR addr, CORE_ADDR pc)
{
struct frame_info *fi;
enum frame_type type;
fi = (struct frame_info *)
obstack_alloc (&frame_cache_obstack,
sizeof (struct frame_info));
/* Zero all fields by default. */
memset (fi, 0, sizeof (struct frame_info));
fi->frame = addr;
fi->pc = pc;
/* NOTE: cagney/2002-11-18: The code segments, found in
create_new_frame and get_prev_frame(), that initializes the
frames type is subtly different. The latter only updates ->type
when it encounters a SIGTRAMP_FRAME or DUMMY_FRAME. This stops
get_prev_frame() overriding the frame's type when the INIT code
has previously set it. This is really somewhat bogus. The
initialization, as seen in create_new_frame(), should occur
before the INIT function has been called. */
if (DEPRECATED_USE_GENERIC_DUMMY_FRAMES
&& (DEPRECATED_PC_IN_CALL_DUMMY_P ()
? DEPRECATED_PC_IN_CALL_DUMMY (pc, 0, 0)
: pc_in_dummy_frame (pc)))
/* NOTE: cagney/2002-11-11: Does this even occure? */
type = DUMMY_FRAME;
else
{
char *name;
find_pc_partial_function (pc, &name, NULL, NULL);
if (PC_IN_SIGTRAMP (fi->pc, name))
type = SIGTRAMP_FRAME;
else
type = NORMAL_FRAME;
}
fi->type = type;
if (INIT_EXTRA_FRAME_INFO_P ())
INIT_EXTRA_FRAME_INFO (0, fi);
/* Select/initialize an unwind function. */
set_unwind_by_pc (fi->pc, fi->frame, &fi->register_unwind,
&fi->pc_unwind, &fi->id_unwind);
return fi;
}
/* Return the frame that FRAME calls (NULL if FRAME is the innermost
frame). */
struct frame_info *
get_next_frame (struct frame_info *frame)
{
return frame->next;
}
/* Flush the entire frame cache. */
void
flush_cached_frames (void)
{
/* Since we can't really be sure what the first object allocated was */
obstack_free (&frame_cache_obstack, 0);
obstack_init (&frame_cache_obstack);
current_frame = NULL; /* Invalidate cache */
select_frame (NULL);
annotate_frames_invalid ();
}
/* Flush the frame cache, and start a new one if necessary. */
void
reinit_frame_cache (void)
{
flush_cached_frames ();
/* FIXME: The inferior_ptid test is wrong if there is a corefile. */
if (PIDGET (inferior_ptid) != 0)
{
select_frame (get_current_frame ());
}
}
/* Return a structure containing various interesting information
about the frame that called NEXT_FRAME. Returns NULL
if there is no such frame. */
struct frame_info *
get_prev_frame (struct frame_info *next_frame)
{
CORE_ADDR address = 0;
struct frame_info *prev;
int fromleaf;
/* Return the inner-most frame, when the caller passes in NULL. */
/* NOTE: cagney/2002-11-09: Not sure how this would happen. The
caller should have previously obtained a valid frame using
get_selected_frame() and then called this code - only possibility
I can think of is code behaving badly. */
if (next_frame == NULL)
{
/* NOTE: cagney/2002-11-09: There was a code segment here that
would error out when CURRENT_FRAME was NULL. The comment
that went with it made the claim ...
``This screws value_of_variable, which just wants a nice
clean NULL return from block_innermost_frame if there are no
frames. I don't think I've ever seen this message happen
otherwise. And returning NULL here is a perfectly legitimate
thing to do.''
Per the above, this code shouldn't even be called with a NULL
NEXT_FRAME. */
return current_frame;
}
/* Only try to do the unwind once. */
if (next_frame->prev_p)
return next_frame->prev;
next_frame->prev_p = 1;
/* On some machines it is possible to call a function without
setting up a stack frame for it. On these machines, we
define this macro to take two args; a frameinfo pointer
identifying a frame and a variable to set or clear if it is
or isn't leafless. */
/* Still don't want to worry about this except on the innermost
frame. This macro will set FROMLEAF if NEXT_FRAME is a frameless
function invocation. */
if (next_frame->next == NULL)
/* FIXME: 2002-11-09: Frameless functions can occure anywhere in
the frame chain, not just the inner most frame! The generic,
per-architecture, frame code should handle this and the below
should simply be removed. */
fromleaf = FRAMELESS_FUNCTION_INVOCATION (next_frame);
else
fromleaf = 0;
if (fromleaf)
/* A frameless inner-most frame. The `FP' (which isn't an
architecture frame-pointer register!) of the caller is the same
as the callee. */
/* FIXME: 2002-11-09: There isn't any reason to special case this
edge condition. Instead the per-architecture code should hande
it locally. */
address = get_frame_base (next_frame);
else
{
/* Two macros defined in tm.h specify the machine-dependent
actions to be performed here.
First, get the frame's chain-pointer.
If that is zero, the frame is the outermost frame or a leaf
called by the outermost frame. This means that if start
calls main without a frame, we'll return 0 (which is fine
anyway).
Nope; there's a problem. This also returns when the current
routine is a leaf of main. This is unacceptable. We move
this to after the ffi test; I'd rather have backtraces from
start go curfluy than have an abort called from main not show
main. */
address = FRAME_CHAIN (next_frame);
/* FIXME: cagney/2002-06-08: There should be two tests here.
The first would check for a valid frame chain based on a user
selectable policy. The default being ``stop at main'' (as
implemented by generic_func_frame_chain_valid()). Other
policies would be available - stop at NULL, .... The second
test, if provided by the target architecture, would check for
more exotic cases - most target architectures wouldn't bother
with this second case. */
if (!FRAME_CHAIN_VALID (address, next_frame))
return 0;
}
if (address == 0)
return 0;
/* Create an initially zero previous frame. */
prev = (struct frame_info *)
obstack_alloc (&frame_cache_obstack,
sizeof (struct frame_info));
memset (prev, 0, sizeof (struct frame_info));
/* Link it in. */
next_frame->prev = prev;
prev->next = next_frame;
prev->frame = address;
prev->level = next_frame->level + 1;
/* FIXME: cagney/2002-11-18: Should be setting the frame's type
here, before anything else, and not last. Various INIT functions
are full of work-arounds for the frames type not being set
correctly from the word go. Ulgh! */
prev->type = NORMAL_FRAME;
/* This change should not be needed, FIXME! We should determine
whether any targets *need* DEPRECATED_INIT_FRAME_PC to happen
after INIT_EXTRA_FRAME_INFO and come up with a simple way to
express what goes on here.
INIT_EXTRA_FRAME_INFO is called from two places: create_new_frame
(where the PC is already set up) and here (where it isn't).
DEPRECATED_INIT_FRAME_PC is only called from here, always after
INIT_EXTRA_FRAME_INFO.
The catch is the MIPS, where INIT_EXTRA_FRAME_INFO requires the
PC value (which hasn't been set yet). Some other machines appear
to require INIT_EXTRA_FRAME_INFO before they can do
DEPRECATED_INIT_FRAME_PC. Phoo.
We shouldn't need DEPRECATED_INIT_FRAME_PC_FIRST to add more
complication to an already overcomplicated part of GDB.
gnu@cygnus.com, 15Sep92.
Assuming that some machines need DEPRECATED_INIT_FRAME_PC after
INIT_EXTRA_FRAME_INFO, one possible scheme:
SETUP_INNERMOST_FRAME(): Default version is just create_new_frame
(read_fp ()), read_pc ()). Machines with extra frame info would
do that (or the local equivalent) and then set the extra fields.
SETUP_ARBITRARY_FRAME(argc, argv): Only change here is that
create_new_frame would no longer init extra frame info;
SETUP_ARBITRARY_FRAME would have to do that.
INIT_PREV_FRAME(fromleaf, prev) Replace INIT_EXTRA_FRAME_INFO and
DEPRECATED_INIT_FRAME_PC. This should also return a flag saying
whether to keep the new frame, or whether to discard it, because
on some machines (e.g. mips) it is really awkward to have
FRAME_CHAIN_VALID called *before* INIT_EXTRA_FRAME_INFO (there is
no good way to get information deduced in FRAME_CHAIN_VALID into
the extra fields of the new frame). std_frame_pc(fromleaf, prev)
This is the default setting for INIT_PREV_FRAME. It just does
what the default DEPRECATED_INIT_FRAME_PC does. Some machines
will call it from INIT_PREV_FRAME (either at the beginning, the
end, or in the middle). Some machines won't use it.
kingdon@cygnus.com, 13Apr93, 31Jan94, 14Dec94. */
/* NOTE: cagney/2002-11-09: Just ignore the above! There is no
reason for things to be this complicated.
The trick is to assume that there is always a frame. Instead of
special casing the inner-most frame, create fake frame
(containing the hardware registers) that is inner to the
user-visible inner-most frame (...) and then unwind from that.
That way architecture code can use use the standard
frame_XX_unwind() functions and not differentiate between the
inner most and any other case.
Since there is always a frame to unwind from, there is always
somewhere (NEXT_FRAME) to store all the info needed to construct
a new (previous) frame without having to first create it. This
means that the convolution below - needing to carefully order a
frame's initialization - isn't needed.
The irony here though, is that FRAME_CHAIN(), at least for a more
up-to-date architecture, always calls FRAME_SAVED_PC(), and
FRAME_SAVED_PC() computes the PC but without first needing the
frame! Instead of the convolution below, we could have simply
called FRAME_SAVED_PC() and been done with it! Note that
FRAME_SAVED_PC() is being superseed by frame_pc_unwind() and that
function does have somewhere to cache that PC value. */
if (DEPRECATED_INIT_FRAME_PC_FIRST_P ())
prev->pc = (DEPRECATED_INIT_FRAME_PC_FIRST (fromleaf, prev));
if (INIT_EXTRA_FRAME_INFO_P ())
INIT_EXTRA_FRAME_INFO (fromleaf, prev);
/* This entry is in the frame queue now, which is good since
FRAME_SAVED_PC may use that queue to figure out its value (see
tm-sparc.h). We want the pc saved in the inferior frame. */
if (DEPRECATED_INIT_FRAME_PC_P ())
prev->pc = DEPRECATED_INIT_FRAME_PC (fromleaf, prev);
/* If ->frame and ->pc are unchanged, we are in the process of
getting ourselves into an infinite backtrace. Some architectures
check this in FRAME_CHAIN or thereabouts, but it seems like there
is no reason this can't be an architecture-independent check. */
if (prev->frame == next_frame->frame
&& prev->pc == next_frame->pc)
{
next_frame->prev = NULL;
obstack_free (&frame_cache_obstack, prev);
return NULL;
}
/* Initialize the code used to unwind the frame PREV based on the PC
(and probably other architectural information). The PC lets you
check things like the debug info at that point (dwarf2cfi?) and
use that to decide how the frame should be unwound. */
set_unwind_by_pc (prev->pc, prev->frame, &prev->register_unwind,
&prev->pc_unwind, &prev->id_unwind);
/* NOTE: cagney/2002-11-18: The code segments, found in
create_new_frame and get_prev_frame(), that initializes the
frames type is subtly different. The latter only updates ->type
when it encounters a SIGTRAMP_FRAME or DUMMY_FRAME. This stops
get_prev_frame() overriding the frame's type when the INIT code
has previously set it. This is really somewhat bogus. The
initialization, as seen in create_new_frame(), should occur
before the INIT function has been called. */
if (DEPRECATED_USE_GENERIC_DUMMY_FRAMES
&& (DEPRECATED_PC_IN_CALL_DUMMY_P ()
? DEPRECATED_PC_IN_CALL_DUMMY (prev->pc, 0, 0)
: pc_in_dummy_frame (prev->pc)))
prev->type = DUMMY_FRAME;
else
{
/* FIXME: cagney/2002-11-10: This should be moved to before the
INIT code above so that the INIT code knows what the frame's
type is (in fact, for a [generic] dummy-frame, the type can
be set and then the entire initialization can be skipped.
Unforunatly, its the INIT code that sets the PC (Hmm, catch
22). */
char *name;
find_pc_partial_function (prev->pc, &name, NULL, NULL);
if (PC_IN_SIGTRAMP (prev->pc, name))
prev->type = SIGTRAMP_FRAME;
/* FIXME: cagney/2002-11-11: Leave prev->type alone. Some
architectures are forcing the frame's type in INIT so we
don't want to override it here. Remember, NORMAL_FRAME == 0,
so it all works (just :-/). Once this initialization is
moved to the start of this function, all this nastness will
go away. */
}
return prev;
}
CORE_ADDR
get_frame_pc (struct frame_info *frame)
{
return frame->pc;
}
static int
pc_notcurrent (struct frame_info *frame)
{
/* If FRAME is not the innermost frame, that normally means that
FRAME->pc points at the return instruction (which is *after* the
call instruction), and we want to get the line containing the
call (because the call is where the user thinks the program is).
However, if the next frame is either a SIGTRAMP_FRAME or a
DUMMY_FRAME, then the next frame will contain a saved interrupt
PC and such a PC indicates the current (rather than next)
instruction/line, consequently, for such cases, want to get the
line containing fi->pc. */
struct frame_info *next = get_next_frame (frame);
int notcurrent = (next != NULL && get_frame_type (next) == NORMAL_FRAME);
return notcurrent;
}
void
find_frame_sal (struct frame_info *frame, struct symtab_and_line *sal)
{
(*sal) = find_pc_line (frame->pc, pc_notcurrent (frame));
}
/* Per "frame.h", return the ``address'' of the frame. Code should
really be using get_frame_id(). */
CORE_ADDR
get_frame_base (struct frame_info *fi)
{
return fi->frame;
}
/* Level of the selected frame: 0 for innermost, 1 for its caller, ...
or -1 for a NULL frame. */
int
frame_relative_level (struct frame_info *fi)
{
if (fi == NULL)
return -1;
else
return fi->level;
}
enum frame_type
get_frame_type (struct frame_info *frame)
{
/* Some targets still don't use [generic] dummy frames. Catch them
here. */
if (!DEPRECATED_USE_GENERIC_DUMMY_FRAMES
&& deprecated_frame_in_dummy (frame))
return DUMMY_FRAME;
return frame->type;
}
void
deprecated_set_frame_type (struct frame_info *frame, enum frame_type type)
{
/* Arrrg! See comment in "frame.h". */
frame->type = type;
}
#ifdef FRAME_FIND_SAVED_REGS
/* XXX - deprecated. This is a compatibility function for targets
that do not yet implement FRAME_INIT_SAVED_REGS. */
/* Find the addresses in which registers are saved in FRAME. */
void
deprecated_get_frame_saved_regs (struct frame_info *frame,
struct frame_saved_regs *saved_regs_addr)
{
if (frame->saved_regs == NULL)
{
frame->saved_regs = (CORE_ADDR *)
frame_obstack_alloc (SIZEOF_FRAME_SAVED_REGS);
}
if (saved_regs_addr == NULL)
{
struct frame_saved_regs saved_regs;
FRAME_FIND_SAVED_REGS (frame, saved_regs);
memcpy (frame->saved_regs, &saved_regs, SIZEOF_FRAME_SAVED_REGS);
}
else
{
FRAME_FIND_SAVED_REGS (frame, *saved_regs_addr);
memcpy (frame->saved_regs, saved_regs_addr, SIZEOF_FRAME_SAVED_REGS);
}
}
#endif
struct frame_extra_info *
get_frame_extra_info (struct frame_info *fi)
{
return fi->extra_info;
}
struct frame_extra_info *
frame_extra_info_zalloc (struct frame_info *fi, long size)
{
fi->extra_info = frame_obstack_alloc (size);
memset (fi->extra_info, 0, size);
return fi->extra_info;
}
void
deprecated_update_frame_pc_hack (struct frame_info *frame, CORE_ADDR pc)
{
/* See comment in "frame.h". */
frame->pc = pc;
}
void
deprecated_update_frame_base_hack (struct frame_info *frame, CORE_ADDR base)
{
/* See comment in "frame.h". */
frame->frame = base;
}
void
_initialize_frame (void)
{
obstack_init (&frame_cache_obstack);
}
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