#include "builtin-regs.h"
#include "gdb_obstack.h"
#include "dummy-frame.h"
+#include "sentinel-frame.h"
#include "gdbcore.h"
#include "annotate.h"
#include "language.h"
#include "frame-unwind.h"
+#include "command.h"
+#include "gdbcmd.h"
+
+/* Flag to indicate whether backtraces should stop at main. */
+
+static int backtrace_below_main;
/* Return a frame uniq ID that can be used to, later, re-find the
frame. */
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;
- }
+ /* NOTE: cagney/2002-11-27: A program trying to unwind a NULL frame
+ is broken. There is always a frame. If there, for some reason,
+ isn't, there is some pretty busted code as it should have
+ detected the problem before calling here. */
+ gdb_assert (frame != NULL);
/* Ask this frame to unwind its register. */
frame->unwind->reg (frame, &frame->unwind_cache, regnum,
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);
+ /* Obtain the register value by unwinding the register from the next
+ (more inner frame). */
+ gdb_assert (frame != NULL && frame->next != NULL);
+ frame_register_unwind (frame->next, regnum, optimizedp, lvalp, addrp,
+ realnump, bufferp);
}
void
-frame_unwind_signed_register (struct frame_info *frame, int regnum,
- LONGEST *val)
+frame_unwind_register (struct frame_info *frame, int regnum, void *buf)
{
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);
+}
+
+void
+frame_unwind_signed_register (struct frame_info *frame, int regnum,
+ LONGEST *val)
+{
+ void *buf = alloca (MAX_REGISTER_RAW_SIZE);
+ frame_unwind_register (frame, regnum, buf);
(*val) = extract_signed_integer (buf, REGISTER_VIRTUAL_SIZE (regnum));
}
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);
+ frame_unwind_register (frame, regnum, buf);
(*val) = extract_unsigned_integer (buf, REGISTER_VIRTUAL_SIZE (regnum));
}
+void
+frame_read_register (struct frame_info *frame, int regnum, void *buf)
+{
+ gdb_assert (frame != NULL && frame->next != NULL);
+ frame_unwind_register (frame->next, regnum, buf);
+}
+
void
frame_read_unsigned_register (struct frame_info *frame, int regnum,
ULONGEST *val)
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);
+ gdb_assert (frame != NULL && frame->next != NULL);
+ frame_unwind_unsigned_register (frame->next, 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);
+ /* See note above in frame_read_unsigned_register(). */
+ gdb_assert (frame != NULL && frame->next != NULL);
+ frame_unwind_signed_register (frame->next, regnum, val);
}
static void
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);
+ gdb_assert (frame != NULL && frame->next != NULL);
+ frame_register_unwind (frame->next, regnum, optimizedp, lvalp, addrp,
+ &realnumx, raw_buffer);
}
void
{
int i;
+ if (len < 0)
+ len = strlen (name);
+
/* Search register name space. */
for (i = 0; i < NUM_REGS + NUM_PSEUDO_REGS; i++)
if (REGISTER_NAME (i) && len == strlen (REGISTER_NAME (i))
return builtin_reg_map_regnum_to_name (regnum);
}
+/* Create a sentinel frame. */
+
+struct frame_info *
+create_sentinel_frame (struct regcache *regcache)
+{
+ struct frame_info *frame = FRAME_OBSTACK_ZALLOC (struct frame_info);
+ frame->type = NORMAL_FRAME;
+ frame->level = -1;
+ /* Explicitly initialize the sentinel frame's cache. Provide it
+ with the underlying regcache. In the future additional
+ information, such as the frame's thread will be added. */
+ frame->unwind_cache = sentinel_frame_cache (regcache);
+ /* For the moment there is only one sentinel frame implementation. */
+ frame->unwind = sentinel_frame_unwind;
+ /* Link this frame back to itself. The frame is self referential
+ (the unwound PC is the same as the pc), so make it so. */
+ frame->next = frame;
+ /* Always unwind the PC as part of creating this frame. This
+ ensures that the frame's PC points at something valid. */
+ /* FIXME: cagney/2003-01-10: Problem here. Unwinding a sentinel
+ frame's PC may require information such as the frame's thread's
+ stop reason. Is it possible to get to that? */
+ frame->pc = frame_pc_unwind (frame);
+ return frame;
+}
+
/* Info about the innermost stack frame (contents of FP register) */
static struct frame_info *current_frame;
return fi->saved_regs;
}
-/* Return the innermost (currently executing) stack frame. */
+/* Return the innermost (currently executing) stack frame. This is
+ split into two functions. The function unwind_to_current_frame()
+ is wrapped in catch exceptions so that, even when the unwind of the
+ sentinel frame fails, the function still returns a stack frame. */
+
+static int
+unwind_to_current_frame (struct ui_out *ui_out, void *args)
+{
+ struct frame_info *frame = get_prev_frame (args);
+ /* A sentinel frame can fail to unwind, eg, because it's PC value
+ lands in somewhere like start. */
+ if (frame == NULL)
+ return 1;
+ current_frame = frame;
+ return 0;
+}
struct frame_info *
get_current_frame (void)
{
+ if (!target_has_stack)
+ error ("No stack.");
+ if (!target_has_registers)
+ error ("No registers.");
+ if (!target_has_memory)
+ error ("No memory.");
if (current_frame == NULL)
{
- if (target_has_stack)
- current_frame = create_new_frame (read_fp (), read_pc ());
- else
- error ("No stack.");
+ struct frame_info *sentinel_frame =
+ create_sentinel_frame (current_regcache);
+ if (catch_exceptions (uiout, unwind_to_current_frame, sentinel_frame,
+ NULL, RETURN_MASK_ERROR) != 0)
+ {
+ /* Oops! Fake a current frame? Is this useful? It has a PC
+ of zero, for instance. */
+ current_frame = sentinel_frame;
+ }
}
return current_frame;
}
gdb_assert (FRAME_INIT_SAVED_REGS_P ());
/* Load the saved_regs register cache. */
- if (frame->saved_regs == NULL)
+ if (get_frame_saved_regs (frame) == NULL)
FRAME_INIT_SAVED_REGS (frame);
- if (frame->saved_regs != NULL
- && frame->saved_regs[regnum] != 0)
+ if (get_frame_saved_regs (frame) != NULL
+ && get_frame_saved_regs (frame)[regnum] != 0)
{
if (regnum == SP_REGNUM)
{
*realnump = -1;
if (bufferp != NULL)
store_address (bufferp, REGISTER_RAW_SIZE (regnum),
- frame->saved_regs[regnum]);
+ get_frame_saved_regs (frame)[regnum]);
}
else
{
a local copy of its value. */
*optimizedp = 0;
*lvalp = lval_memory;
- *addrp = frame->saved_regs[regnum];
+ *addrp = get_frame_saved_regs (frame)[regnum];
*realnump = -1;
if (bufferp != NULL)
{
{
regs[regnum]
= frame_obstack_zalloc (REGISTER_RAW_SIZE (regnum));
- read_memory (frame->saved_regs[regnum], regs[regnum],
+ read_memory (get_frame_saved_regs (frame)[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,
+ read_memory (get_frame_saved_regs (frame)[regnum], bufferp,
REGISTER_RAW_SIZE (regnum));
#endif
}
}
/* 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);
- }
+ value. Pass the request down the frame chain to the next frame.
+ Hopefully that will find the register's location, either in a
+ register or in memory. */
+ frame_register (frame, regnum, optimizedp, lvalp, addrp, realnump,
+ bufferp);
}
static CORE_ADDR
frame_saved_regs_pc_unwind (struct frame_info *frame, void **cache)
{
+ gdb_assert (FRAME_SAVED_PC_P ());
return FRAME_SAVED_PC (frame);
}
/* Start out by assuming it's NULL. */
(*id) = null_frame_id;
- if (next_frame->next == NULL)
+ if (frame_relative_level (next_frame) <= 0)
/* 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
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. */
+ gdb_assert (FRAME_CHAIN_P ());
base = FRAME_CHAIN (next_frame);
if (!frame_chain_valid (base, next_frame))
frame_saved_regs_pop (struct frame_info *fi, void **cache,
struct regcache *regcache)
{
+ gdb_assert (POP_FRAME_P ());
POP_FRAME;
}
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 (frame != NULL)
{
- if (get_frame_type (frame) == DUMMY_FRAME)
+ for (frame = get_next_frame (frame);
+ frame_relative_level (frame) >= 0;
+ frame = get_next_frame (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 (get_frame_type (frame) == DUMMY_FRAME)
{
- if (raw_buffer) /* SP register treated specially */
- store_address (raw_buffer, REGISTER_RAW_SIZE (regnum),
- frame->saved_regs[regnum]);
+ 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 (get_frame_pc (frame),
+ get_frame_base (frame)),
+ regnum, raw_buffer);
+ return;
}
- else
+
+ FRAME_INIT_SAVED_REGS (frame);
+ if (get_frame_saved_regs (frame) != NULL
+ && get_frame_saved_regs (frame)[regnum] != 0)
{
- 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));
+ 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),
+ get_frame_saved_regs (frame)[regnum]);
+ }
+ else
+ {
+ if (addrp) /* any other register */
+ *addrp = get_frame_saved_regs (frame)[regnum];
+ if (raw_buffer)
+ read_memory (get_frame_saved_regs (frame)[regnum], raw_buffer,
+ REGISTER_RAW_SIZE (regnum));
+ }
+ return;
}
- return;
}
}
deprecated_read_register_gen (regnum, raw_buffer);
}
+/* Determine the frame's type based on its PC. */
+
+static enum frame_type
+frame_type_from_pc (CORE_ADDR pc)
+{
+ /* FIXME: cagney/2002-11-24: Can't yet directly call
+ pc_in_dummy_frame() as some architectures don't set
+ PC_IN_CALL_DUMMY() to generic_pc_in_call_dummy() (remember the
+ latter is implemented by simply calling pc_in_dummy_frame). */
+ if (DEPRECATED_USE_GENERIC_DUMMY_FRAMES
+ && DEPRECATED_PC_IN_CALL_DUMMY (pc, 0, 0))
+ return DUMMY_FRAME;
+ else
+ {
+ char *name;
+ find_pc_partial_function (pc, &name, NULL, NULL);
+ if (PC_IN_SIGTRAMP (pc, name))
+ return SIGTRAMP_FRAME;
+ else
+ return NORMAL_FRAME;
+ }
+}
+
/* Create an arbitrary (i.e. address specified by user) or innermost frame.
Always returns a non-NULL value. */
create_new_frame (CORE_ADDR addr, CORE_ADDR pc)
{
struct frame_info *fi;
- enum frame_type type;
fi = frame_obstack_zalloc (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;
+ fi->next = create_sentinel_frame (current_regcache);
+ fi->type = frame_type_from_pc (pc);
if (INIT_EXTRA_FRAME_INFO_P ())
INIT_EXTRA_FRAME_INFO (0, fi);
}
/* Return the frame that FRAME calls (NULL if FRAME is the innermost
- frame). */
+ frame). Be careful to not fall off the bottom of the frame chain
+ and onto the sentinel frame. */
struct frame_info *
get_next_frame (struct frame_info *frame)
{
- return frame->next;
+ if (frame->level > 0)
+ return frame->next;
+ else
+ return NULL;
}
/* Flush the entire frame cache. */
}
}
-/* Return a structure containing various interesting information
- about the frame that called NEXT_FRAME. Returns NULL
- if there is no such frame. */
+/* Create the previous frame using the deprecated methods
+ INIT_EXTRA_INFO, INIT_FRAME_PC and INIT_FRAME_PC_FIRST. */
-struct frame_info *
-get_prev_frame (struct frame_info *next_frame)
+static struct frame_info *
+legacy_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;
+ /* This code only works on normal frames. A sentinel frame, where
+ the level is -1, should never reach this code. */
+ gdb_assert (next_frame->level >= 0);
/* On some machines it is possible to call a function without
setting up a stack frame for it. On these machines, we
/* 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)
+ if (next_frame->level == 0)
/* 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
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. */
+ gdb_assert (FRAME_CHAIN_P ());
address = FRAME_CHAIN (next_frame);
if (!frame_chain_valid (address, next_frame))
return prev;
}
+/* 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)
+{
+ struct frame_info *prev_frame;
+
+ /* 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.
+
+ NOTE: cagney/2003-01-10: Talk about code behaving badly. Check
+ block_innermost_frame(). It does the sequence: frame = NULL;
+ while (1) { frame = get_prev_frame (frame); .... }. Ulgh! Why
+ it couldn't be written better, I don't know.
+
+ NOTE: cagney/2003-01-11: I suspect what is happening is
+ block_innermost_frame() is, when the target has no state
+ (registers, memory, ...), still calling this function. The
+ assumption being that this function will return NULL indicating
+ that a frame isn't possible, rather than checking that the target
+ has state and then calling get_current_frame() and
+ get_prev_frame(). This is a guess mind. */
+ 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;
+ }
+
+ /* There is always a frame. If this assertion fails, suspect that
+ something should be calling get_selected_frame() or
+ get_current_frame(). */
+ gdb_assert (next_frame != NULL);
+
+ if (next_frame->level >= 0
+ && !backtrace_below_main
+ && inside_main_func (get_frame_pc (next_frame)))
+ /* Don't unwind past main(), bug always unwind the sentinel frame.
+ Note, this is done _before_ the frame has been marked as
+ previously unwound. That way if the user later decides to
+ allow unwinds past main(), that just happens. */
+ return NULL;
+
+ /* Only try to do the unwind once. */
+ if (next_frame->prev_p)
+ return next_frame->prev;
+ next_frame->prev_p = 1;
+
+ /* If we're inside the entry file, it isn't valid. */
+ /* NOTE: drow/2002-12-25: should there be a way to disable this
+ check? It assumes a single small entry file, and the way some
+ debug readers (e.g. dbxread) figure out which object is the
+ entry file is somewhat hokey. */
+ /* NOTE: cagney/2003-01-10: If there is a way of disabling this test
+ then it should probably be moved to before the ->prev_p test,
+ above. */
+ if (inside_entry_file (get_frame_pc (next_frame)))
+ return NULL;
+
+ /* If any of the old frame initialization methods are around, use
+ the legacy get_prev_frame method. Just don't try to unwind a
+ sentinel frame using that method - it doesn't work. All sentinal
+ frames use the new unwind code. */
+ if ((DEPRECATED_INIT_FRAME_PC_P ()
+ || DEPRECATED_INIT_FRAME_PC_FIRST_P ()
+ || INIT_EXTRA_FRAME_INFO_P ()
+ || FRAME_CHAIN_P ())
+ && next_frame->level >= 0)
+ return legacy_get_prev_frame (next_frame);
+
+ /* Allocate the new frame but do not wire it in to the frame chain.
+ Some (bad) code in INIT_FRAME_EXTRA_INFO tries to look along
+ frame->next to pull some fancy tricks (of course such code is, by
+ definition, recursive). Try to prevent it.
+
+ There is no reason to worry about memory leaks, should the
+ remainder of the function fail. The allocated memory will be
+ quickly reclaimed when the frame cache is flushed, and the `we've
+ been here before' check above will stop repeated memory
+ allocation calls. */
+ prev_frame = FRAME_OBSTACK_ZALLOC (struct frame_info);
+ prev_frame->level = next_frame->level + 1;
+
+ /* Try to unwind the PC. If that doesn't work, assume we've reached
+ the oldest frame and simply return. Is there a better sentinal
+ value? The unwound PC value is then used to initialize the new
+ previous frame's type.
+
+ Note that the pc-unwind is intentionally performed before the
+ frame chain. This is ok since, for old targets, both
+ frame_pc_unwind (nee, FRAME_SAVED_PC) and FRAME_CHAIN()) assume
+ NEXT_FRAME's data structures have already been initialized (using
+ INIT_EXTRA_FRAME_INFO) and hence the call order doesn't matter.
+
+ By unwinding the PC first, it becomes possible to, in the case of
+ a dummy frame, avoid also unwinding the frame ID. This is
+ because (well ignoring the PPC) a dummy frame can be located
+ using NEXT_FRAME's frame ID. */
+
+ prev_frame->pc = frame_pc_unwind (next_frame);
+ if (prev_frame->pc == 0)
+ /* The allocated PREV_FRAME will be reclaimed when the frame
+ obstack is next purged. */
+ return NULL;
+ prev_frame->type = frame_type_from_pc (prev_frame->pc);
+
+ /* Set the unwind functions based on that identified PC. */
+ prev_frame->unwind = frame_unwind_find_by_pc (current_gdbarch,
+ prev_frame->pc);
+
+ /* FIXME: cagney/2003-01-13: A dummy frame doesn't need to unwind
+ the frame ID because the frame ID comes from the previous frame.
+ The other frames do though. True? */
+ {
+ /* FIXME: cagney/2002-12-18: Instead of this hack, should just
+ save the frame ID directly. */
+ struct frame_id id = frame_id_unwind (next_frame);
+ if (!frame_id_p (id))
+ return NULL;
+ prev_frame->frame = id.base;
+ }
+
+ /* Link it in. */
+ next_frame->prev = prev_frame;
+ prev_frame->next = next_frame;
+
+ /* FIXME: cagney/2002-01-19: This call will go away. Instead of
+ initializing extra info, all frames will use the frame_cache
+ (passed to the unwind functions) to store additional frame info.
+ Unfortunatly legacy targets can't use legacy_get_prev_frame() to
+ unwind the sentinel frame and, consequently, are forced to take
+ this code path and rely on the below call to INIT_EXTR_FRAME_INFO
+ to initialize the inner-most frame. */
+ if (INIT_EXTRA_FRAME_INFO_P ())
+ {
+ gdb_assert (prev_frame->level == 0);
+ INIT_EXTRA_FRAME_INFO (0, prev_frame);
+ }
+
+ return prev_frame;
+}
+
CORE_ADDR
get_frame_pc (struct frame_info *frame)
{
deprecated_update_frame_pc_hack (struct frame_info *frame, CORE_ADDR pc)
{
/* See comment in "frame.h". */
+ gdb_assert (frame->next != NULL);
frame->pc = pc;
}
_initialize_frame (void)
{
obstack_init (&frame_cache_obstack);
+
+ /* FIXME: cagney/2003-01-19: This command needs a rename. Suggest
+ `set backtrace {past,beyond,...}-main'. Also suggest adding `set
+ backtrace ...-start' to control backtraces past start. The
+ problem with `below' is that it stops the `up' command. */
+
+ add_setshow_boolean_cmd ("backtrace-below-main", class_obscure,
+ &backtrace_below_main, "\
+Set whether backtraces should continue past \"main\".\n\
+Normally the caller of \"main\" is not of interest, so GDB will terminate\n\
+the backtrace at \"main\". Set this variable if you need to see the rest\n\
+of the stack trace.", "\
+Show whether backtraces should continue past \"main\".\n\
+Normally the caller of \"main\" is not of interest, so GDB will terminate\n\
+the backtrace at \"main\". Set this variable if you need to see the rest\n\
+of the stack trace.",
+ NULL, NULL, &setlist, &showlist);
}
projects / deliverable / binutils-gdb.git / blobdiff