diff options
Diffstat (limited to 'gdb')
| -rw-r--r-- | gdb/ChangeLog | 10 | ||||
| -rw-r--r-- | gdb/frame.c | 276 | ||||
| -rw-r--r-- | gdb/frame.h | 1 | ||||
| -rw-r--r-- | gdb/infrun.c | 2 |
4 files changed, 168 insertions, 121 deletions
diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 924a256..6ffac47 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,13 @@ +2004-03-31 Andrew Cagney <cagney@redhat.com> + + * frame.h (frame_unwind_id): Declare. + * frame.c (frame_unwind_id): New function. + (get_prev_frame_1): New function. + (frame_debug_got_null_frame): New function. + (get_prev_frame): Use frame_debug_got_null_frame. Move unwind + code proper to prev_frame, update description. + * infrun.c (step_over_function): Use frame_unwind_id. + 2004-04-31 J. Brobecker <brobecker@gnat.com> * hppa-tdep.c (hppa32_push_dummy_call): Set the Stack Pointer. diff --git a/gdb/frame.c b/gdb/frame.c index f6aa5cf..d725e87 100644 --- a/gdb/frame.c +++ b/gdb/frame.c @@ -40,6 +40,8 @@ #include "command.h" #include "gdbcmd.h" +static struct frame_info *get_prev_frame_1 (struct frame_info *this_frame); + /* We keep a cache of stack frames, each of which is a "struct frame_info". The innermost one gets allocated (in wait_for_inferior) each time the inferior stops; current_frame @@ -250,6 +252,16 @@ get_frame_id (struct frame_info *fi) return fi->this_id.value; } +struct frame_id +frame_unwind_id (struct frame_info *next_frame) +{ + /* Use prev_frame, and not get_prev_frame. The latter will truncate + the frame chain, leading to this function unintentionally + returning a null_frame_id (e.g., when a caller requests the frame + ID of "main()"s caller. */ + return get_frame_id (get_prev_frame_1 (next_frame)); +} + const struct frame_id null_frame_id; /* All zeros. */ struct frame_id @@ -1720,23 +1732,22 @@ legacy_get_prev_frame (struct frame_info *this_frame) return prev; } -/* Return a structure containing various interesting information - about the frame that called THIS_FRAME. Returns NULL - if there is no such frame. +/* Return a "struct frame_info" corresponding to the frame that called + THIS_FRAME. Returns NULL if there is no such frame. - This function tests some target-independent conditions that should - terminate the frame chain, such as unwinding past main(). It - should not contain any target-dependent tests, such as checking - whether the program-counter is zero. */ + Unlike get_prev_frame, this function always tries to unwind the + frame. */ -struct frame_info * -get_prev_frame (struct frame_info *this_frame) +static struct frame_info * +get_prev_frame_1 (struct frame_info *this_frame) { struct frame_info *prev_frame; + gdb_assert (this_frame != NULL); + if (frame_debug) { - fprintf_unfiltered (gdb_stdlog, "{ get_prev_frame (this_frame="); + fprintf_unfiltered (gdb_stdlog, "{ get_prev_frame_1 (this_frame="); if (this_frame != NULL) fprintf_unfiltered (gdb_stdlog, "%d", this_frame->level); else @@ -1744,6 +1755,136 @@ get_prev_frame (struct frame_info *this_frame) fprintf_unfiltered (gdb_stdlog, ") "); } + /* Only try to do the unwind once. */ + if (this_frame->prev_p) + { + if (frame_debug) + { + fprintf_unfiltered (gdb_stdlog, "-> "); + fprint_frame (gdb_stdlog, this_frame->prev); + fprintf_unfiltered (gdb_stdlog, " // cached \n"); + } + return this_frame->prev; + } + this_frame->prev_p = 1; + + /* If any of the old frame initialization methods are around, use + the legacy get_prev_frame method. */ + if (legacy_frame_p (current_gdbarch)) + { + prev_frame = legacy_get_prev_frame (this_frame); + return prev_frame; + } + + /* Check that this frame's ID was valid. If it wasn't, don't try to + unwind to the prev frame. Be careful to not apply this test to + the sentinel frame. */ + if (this_frame->level >= 0 && !frame_id_p (get_frame_id (this_frame))) + { + if (frame_debug) + { + fprintf_unfiltered (gdb_stdlog, "-> "); + fprint_frame (gdb_stdlog, NULL); + fprintf_unfiltered (gdb_stdlog, " // this ID is NULL }\n"); + } + return NULL; + } + + /* Check that this frame's ID isn't inner to (younger, below, next) + the next frame. This happens when a frame unwind goes backwards. + Since the sentinel frame doesn't really exist, don't compare the + inner-most against that sentinel. */ + if (this_frame->level > 0 + && frame_id_inner (get_frame_id (this_frame), + get_frame_id (this_frame->next))) + error ("Previous frame inner to this frame (corrupt stack?)"); + + /* Check that this and the next frame are not identical. If they + are, there is most likely a stack cycle. As with the inner-than + test above, avoid comparing the inner-most and sentinel frames. */ + if (this_frame->level > 0 + && frame_id_eq (get_frame_id (this_frame), + get_frame_id (this_frame->next))) + error ("Previous frame identical to this frame (corrupt stack?)"); + + /* 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 = this_frame->level + 1; + + /* Don't yet compute ->unwind (and hence ->type). It is computed + on-demand in get_frame_type, frame_register_unwind, and + get_frame_id. */ + + /* Don't yet compute the frame's ID. It is computed on-demand by + get_frame_id(). */ + + /* The unwound frame ID is validate at the start of this function, + as part of the logic to decide if that frame should be further + unwound, and not here while the prev frame is being created. + Doing this makes it possible for the user to examine a frame that + has an invalid frame ID. + + Some very old VAX code noted: [...] For the sake of argument, + suppose that the stack is somewhat trashed (which is one reason + that "info frame" exists). So, return 0 (indicating we don't + know the address of the arglist) if we don't know what frame this + frame calls. */ + + /* Link it in. */ + this_frame->prev = prev_frame; + prev_frame->next = this_frame; + + if (frame_debug) + { + fprintf_unfiltered (gdb_stdlog, "-> "); + fprint_frame (gdb_stdlog, prev_frame); + fprintf_unfiltered (gdb_stdlog, " }\n"); + } + + return prev_frame; +} + +/* Debug routine to print a NULL frame being returned. */ + +static void +frame_debug_got_null_frame (struct ui_file *file, + struct frame_info *this_frame, + const char *reason) +{ + if (frame_debug) + { + fprintf_unfiltered (gdb_stdlog, "{ get_prev_frame (this_frame="); + if (this_frame != NULL) + fprintf_unfiltered (gdb_stdlog, "%d", this_frame->level); + else + fprintf_unfiltered (gdb_stdlog, "<NULL>"); + fprintf_unfiltered (gdb_stdlog, ") -> // %s}\n", reason); + } +} + +/* Return a structure containing various interesting information about + the frame that called THIS_FRAME. Returns NULL if there is entier + no such frame or the frame fails any of a set of target-independent + condition that should terminate the frame chain (e.g., as unwinding + past main()). + + This function should not contain target-dependent tests, such as + checking whether the program-counter is zero. */ + +struct frame_info * +get_prev_frame (struct frame_info *this_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 @@ -1776,6 +1917,7 @@ get_prev_frame (struct frame_info *this_frame) Per the above, this code shouldn't even be called with a NULL THIS_FRAME. */ + frame_debug_got_null_frame (gdb_stdlog, this_frame, "this_frame NULL"); return current_frame; } @@ -1796,8 +1938,7 @@ get_prev_frame (struct frame_info *this_frame) previously unwound. That way if the user later decides to allow unwinds past main(), that just happens. */ { - if (frame_debug) - fprintf_unfiltered (gdb_stdlog, "-> NULL // inside main func }\n"); + frame_debug_got_null_frame (gdb_stdlog, this_frame, "inside main func"); return NULL; } @@ -1836,28 +1977,10 @@ get_prev_frame (struct frame_info *this_frame) && this_frame->type != DUMMY_FRAME && this_frame->level >= 0 && inside_entry_func (this_frame)) { - if (frame_debug) - { - fprintf_unfiltered (gdb_stdlog, "-> "); - fprint_frame (gdb_stdlog, NULL); - fprintf_unfiltered (gdb_stdlog, "// inside entry func }\n"); - } + frame_debug_got_null_frame (gdb_stdlog, this_frame, "inside entry func"); return NULL; } - /* Only try to do the unwind once. */ - if (this_frame->prev_p) - { - if (frame_debug) - { - fprintf_unfiltered (gdb_stdlog, "-> "); - fprint_frame (gdb_stdlog, this_frame->prev); - fprintf_unfiltered (gdb_stdlog, " // cached \n"); - } - return this_frame->prev; - } - this_frame->prev_p = 1; - /* If we're inside the entry file, it isn't valid. Don't apply this test to a dummy frame - dummy frame PC's typically land in the entry file. Don't apply this test to the sentinel frame. @@ -1883,98 +2006,11 @@ get_prev_frame (struct frame_info *this_frame) && this_frame->type != DUMMY_FRAME && this_frame->level >= 0 && deprecated_inside_entry_file (get_frame_pc (this_frame))) { - if (frame_debug) - { - fprintf_unfiltered (gdb_stdlog, "-> "); - fprint_frame (gdb_stdlog, NULL); - fprintf_unfiltered (gdb_stdlog, " // inside entry file }\n"); - } + frame_debug_got_null_frame (gdb_stdlog, this_frame, "inside entry file"); return NULL; } - /* If any of the old frame initialization methods are around, use - the legacy get_prev_frame method. */ - if (legacy_frame_p (current_gdbarch)) - { - prev_frame = legacy_get_prev_frame (this_frame); - return prev_frame; - } - - /* Check that this frame's ID was valid. If it wasn't, don't try to - unwind to the prev frame. Be careful to not apply this test to - the sentinel frame. */ - if (this_frame->level >= 0 && !frame_id_p (get_frame_id (this_frame))) - { - if (frame_debug) - { - fprintf_unfiltered (gdb_stdlog, "-> "); - fprint_frame (gdb_stdlog, NULL); - fprintf_unfiltered (gdb_stdlog, " // this ID is NULL }\n"); - } - return NULL; - } - - /* Check that this frame's ID isn't inner to (younger, below, next) - the next frame. This happens when a frame unwind goes backwards. - Since the sentinel frame doesn't really exist, don't compare the - inner-most against that sentinel. */ - if (this_frame->level > 0 - && frame_id_inner (get_frame_id (this_frame), - get_frame_id (this_frame->next))) - error ("Previous frame inner to this frame (corrupt stack?)"); - - /* Check that this and the next frame are not identical. If they - are, there is most likely a stack cycle. As with the inner-than - test above, avoid comparing the inner-most and sentinel frames. */ - if (this_frame->level > 0 - && frame_id_eq (get_frame_id (this_frame), - get_frame_id (this_frame->next))) - error ("Previous frame identical to this frame (corrupt stack?)"); - - /* 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 = this_frame->level + 1; - - /* Don't yet compute ->unwind (and hence ->type). It is computed - on-demand in get_frame_type, frame_register_unwind, and - get_frame_id. */ - - /* Don't yet compute the frame's ID. It is computed on-demand by - get_frame_id(). */ - - /* The unwound frame ID is validate at the start of this function, - as part of the logic to decide if that frame should be further - unwound, and not here while the prev frame is being created. - Doing this makes it possible for the user to examine a frame that - has an invalid frame ID. - - Some very old VAX code noted: [...] For the sake of argument, - suppose that the stack is somewhat trashed (which is one reason - that "info frame" exists). So, return 0 (indicating we don't - know the address of the arglist) if we don't know what frame this - frame calls. */ - - /* Link it in. */ - this_frame->prev = prev_frame; - prev_frame->next = this_frame; - - if (frame_debug) - { - fprintf_unfiltered (gdb_stdlog, "-> "); - fprint_frame (gdb_stdlog, prev_frame); - fprintf_unfiltered (gdb_stdlog, " }\n"); - } - - return prev_frame; + return get_prev_frame_1 (this_frame); } CORE_ADDR diff --git a/gdb/frame.h b/gdb/frame.h index 028167d..3e38c61 100644 --- a/gdb/frame.h +++ b/gdb/frame.h @@ -312,6 +312,7 @@ extern CORE_ADDR get_frame_base (struct frame_info *); frame after a frame cache flush (and other similar operations). If FI is NULL, return the null_frame_id. */ extern struct frame_id get_frame_id (struct frame_info *fi); +extern struct frame_id frame_unwind_id (struct frame_info *next_frame); /* Assuming that a frame is `normal', return its base-address, or 0 if the information isn't available. NOTE: This address is really only diff --git a/gdb/infrun.c b/gdb/infrun.c index aaf6ac8..b1d03e3 100644 --- a/gdb/infrun.c +++ b/gdb/infrun.c @@ -2959,7 +2959,7 @@ step_over_function (struct execution_control_state *ecs) sr_id = get_frame_id (get_current_frame ()); } else - sr_id = get_frame_id (get_prev_frame (get_current_frame ())); + sr_id = frame_unwind_id (get_current_frame ()); step_resume_breakpoint = set_momentary_breakpoint (sr_sal, sr_id, bp_step_resume); |