* dummy-frame.c: Include "observer.h".
(dummy_frame_push): Do not check for stale frames.
(dummy_frame_pop): New function.
(cleanup_dummy_frames): New function.
(_initialize_dummy_frame): Install it as inferior_created observer.
* frame.h (struct frame_id): Update comments.
(frame_id_inner): Remove prototype.
* frame.c (frame_id_inner): Make static. Add comments.
(frame_find_by_id): Update frame_id_inner safety net check to avoid
false positives for targets using non-contiguous stack ranges.
(get_prev_frame_1): Update frame_id_inner safety net check.
(frame_pop): Call dummy_frame_pop when popping a dummy frame.
* stack.c (return_command): Directly pop the selected frame.
* infrun.c (handle_inferior_event): Remove dead code.
* i386-tdep.c (i386_push_dummy_call): Update comment.
+2008-08-26 Ulrich Weigand <uweigand@de.ibm.com>
+
+ * dummy-frame.h (dummy_frame_pop): Add prototype.
+ * dummy-frame.c: Include "observer.h".
+ (dummy_frame_push): Do not check for stale frames.
+ (dummy_frame_pop): New function.
+ (cleanup_dummy_frames): New function.
+ (_initialize_dummy_frame): Install it as inferior_created observer.
+
+ * frame.h (struct frame_id): Update comments.
+ (frame_id_inner): Remove prototype.
+ * frame.c (frame_id_inner): Make static. Add comments.
+ (frame_find_by_id): Update frame_id_inner safety net check to avoid
+ false positives for targets using non-contiguous stack ranges.
+ (get_prev_frame_1): Update frame_id_inner safety net check.
+ (frame_pop): Call dummy_frame_pop when popping a dummy frame.
+
+ * stack.c (return_command): Directly pop the selected frame.
+ * infrun.c (handle_inferior_event): Remove dead code.
+ * i386-tdep.c (i386_push_dummy_call): Update comment.
+
2008-08-26 Ulrich Weigand <uweigand@de.ibm.com>
* breakpoint.c (remove_breakpoint): Do not fail if unable to remove
#include "command.h"
#include "gdbcmd.h"
#include "gdb_string.h"
+#include "observer.h"
/* Dummy frame. This saves the processor state just prior to setting
up the inferior function call. Older targets save the registers
dummy_frame_push (struct regcache *caller_regcache,
const struct frame_id *dummy_id)
{
- struct gdbarch *gdbarch = get_regcache_arch (caller_regcache);
struct dummy_frame *dummy_frame;
- /* Check to see if there are stale dummy frames, perhaps left over
- from when a longjump took us out of a function that was called by
- the debugger. */
- dummy_frame = dummy_frame_stack;
- while (dummy_frame)
- /* FIXME: cagney/2004-08-02: Should just test IDs. */
- if (frame_id_inner (gdbarch, dummy_frame->id, (*dummy_id)))
- /* Stale -- destroy! */
- {
- dummy_frame_stack = dummy_frame->next;
- regcache_xfree (dummy_frame->regcache);
- xfree (dummy_frame);
- dummy_frame = dummy_frame_stack;
- }
- else
- dummy_frame = dummy_frame->next;
-
dummy_frame = XZALLOC (struct dummy_frame);
dummy_frame->regcache = caller_regcache;
dummy_frame->id = (*dummy_id);
dummy_frame_stack = dummy_frame;
}
+/* Pop the dummy frame with ID dummy_id from the dummy-frame stack. */
+
+void
+dummy_frame_pop (struct frame_id dummy_id)
+{
+ struct dummy_frame **dummy_ptr;
+
+ for (dummy_ptr = &dummy_frame_stack;
+ (*dummy_ptr) != NULL;
+ dummy_ptr = &(*dummy_ptr)->next)
+ {
+ struct dummy_frame *dummy = *dummy_ptr;
+ if (frame_id_eq (dummy->id, dummy_id))
+ {
+ *dummy_ptr = dummy->next;
+ regcache_xfree (dummy->regcache);
+ xfree (dummy);
+ break;
+ }
+ }
+}
+
+/* There may be stale dummy frames, perhaps left over from when a longjump took us
+ out of a function that was called by the debugger. Clean them up at least once
+ whenever we start a new inferior. */
+
+static void
+cleanup_dummy_frames (struct target_ops *target, int from_tty)
+{
+ struct dummy_frame *dummy, *next;
+
+ for (dummy = dummy_frame_stack; dummy; dummy = next)
+ {
+ next = dummy->next;
+ regcache_xfree (dummy->regcache);
+ xfree (dummy);
+ }
+
+ dummy_frame_stack = NULL;
+}
+
/* Return the dummy frame cache, it contains both the ID, and a
pointer to the regcache. */
struct dummy_frame_cache
_("Print the contents of the internal dummy-frame stack."),
&maintenanceprintlist);
+ observer_attach_inferior_created (cleanup_dummy_frames);
}
extern void dummy_frame_push (struct regcache *regcache,
const struct frame_id *dummy_id);
+extern void dummy_frame_pop (struct frame_id dummy_id);
+
/* If the PC falls in a dummy frame, return a dummy frame
unwinder. */
return eq;
}
-int
+/* Safety net to check whether frame ID L should be inner to
+ frame ID R, according to their stack addresses.
+
+ This method cannot be used to compare arbitrary frames, as the
+ ranges of valid stack addresses may be discontiguous (e.g. due
+ to sigaltstack).
+
+ However, it can be used as safety net to discover invalid frame
+ IDs in certain circumstances.
+
+ * If frame NEXT is the immediate inner frame to THIS, and NEXT
+ is a NORMAL frame, then the stack address of NEXT must be
+ inner-than-or-equal to the stack address of THIS.
+
+ Therefore, if frame_id_inner (THIS, NEXT) holds, some unwind
+ error has occurred.
+
+ * If frame NEXT is the immediate inner frame to THIS, and NEXT
+ is a NORMAL frame, and NEXT and THIS have different stack
+ addresses, no other frame in the frame chain may have a stack
+ address in between.
+
+ Therefore, if frame_id_inner (TEST, THIS) holds, but
+ frame_id_inner (TEST, NEXT) does not hold, TEST cannot refer
+ to a valid frame in the frame chain. */
+
+static int
frame_id_inner (struct gdbarch *gdbarch, struct frame_id l, struct frame_id r)
{
int inner;
struct frame_info *
frame_find_by_id (struct frame_id id)
{
- struct frame_info *frame;
+ struct frame_info *frame, *prev_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))
+ for (frame = get_current_frame (); ; frame = prev_frame)
{
struct frame_id this = get_frame_id (frame);
if (frame_id_eq (id, this))
/* An exact match. */
return frame;
- if (frame_id_inner (get_frame_arch (frame), id, this))
- /* Gone to far. */
+
+ prev_frame = get_prev_frame (frame);
+ if (!prev_frame)
+ return NULL;
+
+ /* As a safety net to avoid unnecessary backtracing while trying
+ to find an invalid ID, we check for a common situation where
+ we can detect from comparing stack addresses that no other
+ frame in the current frame chain can have this ID. See the
+ comment at frame_id_inner for details. */
+ if (get_frame_type (frame) == NORMAL_FRAME
+ && !frame_id_inner (get_frame_arch (frame), id, this)
+ && frame_id_inner (get_frame_arch (prev_frame), id,
+ get_frame_id (prev_frame)))
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;
}
scratch = frame_save_as_regcache (prev_frame);
cleanups = make_cleanup_regcache_xfree (scratch);
+ /* If we are popping a dummy frame, clean up the associated
+ data as well. */
+ if (get_frame_type (this_frame) == DUMMY_FRAME)
+ dummy_frame_pop (get_frame_id (this_frame));
+
/* FIXME: cagney/2003-03-16: It should be possible to tell the
target's register cache that it is about to be hit with a burst
register transfer and that the sequence of register writes should
/* Check that this frame's ID isn't inner to (younger, below, next)
the next frame. This happens when a frame unwind goes backwards.
- Exclude signal trampolines (due to sigaltstack the frame ID can
- go backwards) and sentinel frames (the test is meaningless). */
- if (this_frame->next->level >= 0
- && this_frame->next->unwind->type != SIGTRAMP_FRAME
- && frame_id_inner (get_frame_arch (this_frame), this_id,
+ This check is valid only if the next frame is NORMAL. See the
+ comment at frame_id_inner for details. */
+ if (this_frame->next->unwind->type == NORMAL_FRAME
+ && frame_id_inner (get_frame_arch (this_frame->next), this_id,
get_frame_id (this_frame->next)))
{
if (frame_debug)
frames that do not change the stack but are still distinct and have
some form of distinct identifier (e.g. the ia64 which uses a 2nd
stack for registers). This field is treated as unordered - i.e. will
- not be used in frame ordering comparisons such as frame_id_inner().
+ not be used in frame ordering comparisons.
This field is valid only if special_addr_p is true. Otherwise, this
frame is considered to have a wildcard special address, i.e. one that
unsigned int special_addr_p : 1;
};
-/* Methods for constructing and comparing Frame IDs.
-
- NOTE: Given stackless functions A and B, where A calls B (and hence
- B is inner-to A). The relationships: !eq(A,B); !eq(B,A);
- !inner(A,B); !inner(B,A); all hold.
-
- This is because, while B is inner-to A, B is not strictly inner-to A.
- Being stackless, they have an identical .stack_addr value, and differ
- only by their unordered .code_addr and/or .special_addr values.
-
- Because frame_id_inner is only used as a safety net (e.g.,
- detect a corrupt stack) the lack of strictness is not a problem.
- Code needing to determine an exact relationship between two frames
- must instead use frame_id_eq and frame_id_unwind. For instance,
- in the above, to determine that A stepped-into B, the equation
- "A.id != B.id && A.id == id_unwind (B)" can be used. */
+/* Methods for constructing and comparing Frame IDs. */
/* For convenience. All fields are zero. */
extern const struct frame_id null_frame_id;
either L or R have a zero .func, then the same frame base. */
extern int frame_id_eq (struct frame_id l, struct frame_id r);
-/* Returns non-zero when L is strictly inner-than R (they have
- different frame .bases). Neither L, nor R can be `null'. See note
- above about frameless functions. */
-extern int frame_id_inner (struct gdbarch *gdbarch, struct frame_id l,
- struct frame_id r);
-
/* Write the internal representation of a frame ID on the specified
stream. */
extern void fprint_frame_id (struct ui_file *file, struct frame_id id);
(i386_frame_this_id, i386_sigtramp_frame_this_id,
i386_dummy_id). It's there, since all frame unwinders for
a given target have to agree (within a certain margin) on the
- definition of the stack address of a frame. Otherwise
- frame_id_inner() won't work correctly. Since DWARF2/GCC uses the
+ definition of the stack address of a frame. Otherwise frame id
+ comparison might not work correctly. Since DWARF2/GCC uses the
stack address *before* the function call as a frame's CFA. On
the i386, when %ebp is used as a frame pointer, the offset
between the contents %ebp and the CFA as defined by GCC. */
tss->current_line = stop_pc_sal.line;
tss->current_symtab = stop_pc_sal.symtab;
- /* In the case where we just stepped out of a function into the
- middle of a line of the caller, continue stepping, but
- step_frame_id must be modified to current frame */
-#if 0
- /* NOTE: cagney/2003-10-16: I think this frame ID inner test is too
- generous. It will trigger on things like a step into a frameless
- stackless leaf function. I think the logic should instead look
- at the unwound frame ID has that should give a more robust
- indication of what happened. */
- if (step - ID == current - ID)
- still stepping in same function;
- else if (step - ID == unwind (current - ID))
- stepped into a function;
- else
- stepped out of a function;
- /* Of course this assumes that the frame ID unwind code is robust
- and we're willing to introduce frame unwind logic into this
- function. Fortunately, those days are nearly upon us. */
-#endif
- {
- struct frame_info *frame = get_current_frame ();
- struct frame_id current_frame = get_frame_id (frame);
- if (!(frame_id_inner (get_frame_arch (frame), current_frame,
- step_frame_id)))
- step_frame_id = current_frame;
- }
-
if (debug_infrun)
fprintf_unfiltered (gdb_stdlog, "infrun: keep going\n");
keep_going (ecs);
error (_("Not confirmed"));
}
- /* NOTE: cagney/2003-01-18: Is this silly? Rather than pop each
- frame in turn, should this code just go straight to the relevant
- frame and pop that? */
-
- /* First discard all frames inner-to the selected frame (making the
- selected frame current). */
- {
- struct frame_id selected_id = get_frame_id (get_selected_frame (NULL));
- while (!frame_id_eq (selected_id, get_frame_id (get_current_frame ())))
- {
- struct frame_info *frame = get_current_frame ();
- if (frame_id_inner (get_frame_arch (frame), selected_id,
- get_frame_id (frame)))
- /* Caught in the safety net, oops! We've gone way past the
- selected frame. */
- error (_("Problem while popping stack frames (corrupt stack?)"));
- frame_pop (get_current_frame ());
- }
- }
-
- /* Second discard the selected frame (which is now also the current
- frame). */
- frame_pop (get_current_frame ());
+ /* Discard the selected frame and all frames inner-to it. */
+ frame_pop (get_selected_frame (NULL));
/* Store RETURN_VALUE in the just-returned register set. */
if (return_value != NULL)
projects / binutils-gdb.git / commitdiff