diff options
Diffstat (limited to 'gdb/frame.c')
| -rw-r--r-- | gdb/frame.c | 236 |
1 files changed, 149 insertions, 87 deletions
diff --git a/gdb/frame.c b/gdb/frame.c index bf860fe2ccd..267d484b606 100644 --- a/gdb/frame.c +++ b/gdb/frame.c @@ -135,26 +135,94 @@ frame_find_by_id (struct frame_id id) } CORE_ADDR -frame_pc_unwind (struct frame_info *frame) +frame_pc_unwind (struct frame_info *this_frame) { - if (!frame->pc_unwind_cache_p) + if (!this_frame->pc_unwind_cache_p) { - frame->pc_unwind_cache = frame->unwind->pc (frame, &frame->unwind_cache); - frame->pc_unwind_cache_p = 1; + CORE_ADDR pc; + if (gdbarch_unwind_pc_p (current_gdbarch)) + { + /* The right way. The `pure' way. The one true way. This + method depends solely on the register-unwind code to + determine the value of registers in THIS frame, and hence + the value of this frame's PC (resume address). A typical + implementation is no more than: + + frame_unwind_register (this_frame, ISA_PC_REGNUM, buf); + return extract_address (buf, size of ISA_PC_REGNUM); + + Note: this method is very heavily dependent on a correct + register-unwind implementation, it pays to fix that + method first; this method is frame type agnostic, since + it only deals with register values, it works with any + frame. This is all in stark contrast to the old + FRAME_SAVED_PC which would try to directly handle all the + different ways that a PC could be unwound. */ + pc = gdbarch_unwind_pc (current_gdbarch, this_frame); + } + else if (this_frame->level < 0) + { + /* FIXME: cagney/2003-03-06: Old code and and a sentinel + frame. Do like was always done. Fetch the PC's value + direct from the global registers array (via read_pc). + This assumes that this frame belongs to the current + global register cache. The assumption is dangerous. */ + pc = read_pc (); + } + else if (DEPRECATED_FRAME_SAVED_PC_P ()) + { + /* FIXME: cagney/2003-03-06: Old code, but not a sentinel + frame. Do like was always done. Note that this method, + unlike unwind_pc(), tries to handle all the different + frame cases directly. It fails. */ + pc = DEPRECATED_FRAME_SAVED_PC (this_frame); + } + else + internal_error (__FILE__, __LINE__, "No gdbarch_unwind_pc method"); + this_frame->pc_unwind_cache = pc; + this_frame->pc_unwind_cache_p = 1; } - return frame->pc_unwind_cache; + return this_frame->pc_unwind_cache; +} + +static int +do_frame_unwind_register (void *src, int regnum, void *buf) +{ + frame_unwind_register (src, regnum, buf); + return 1; } void -frame_pop (struct frame_info *frame) +frame_pop (struct frame_info *this_frame) { - /* FIXME: cagney/2003-01-18: There is probably a chicken-egg problem - with passing in current_regcache. The pop function needs to be - written carefully so as to not overwrite registers whose [old] - values are needed to restore other registers. Instead, this code - should pass in a scratch cache and, as a second step, restore the - registers using that. */ - frame->unwind->pop (frame, &frame->unwind_cache, current_regcache); + struct regcache *scratch_regcache; + struct cleanup *cleanups; + + if (POP_FRAME_P ()) + { + /* A legacy architecture that has implemented a custom pop + function. All new architectures should instead be using the + generic code below. */ + POP_FRAME; + } + else + { + /* Make a copy of all the register values unwound from this + frame. Save them in a scratch buffer so that there isn't a + race betweening trying to extract the old values from the + current_regcache while, at the same time writing new values + into that same cache. */ + struct regcache *scratch = regcache_xmalloc (current_gdbarch); + struct cleanup *cleanups = make_cleanup_regcache_xfree (scratch); + regcache_save (scratch, do_frame_unwind_register, this_frame); + /* Now copy those saved registers into the current regcache. + Here, regcache_cpy() calls regcache_restore(). */ + regcache_cpy (current_regcache, scratch); + do_cleanups (cleanups); + } + /* We've made right mess of GDB's local state, just discard + everything. */ + target_store_registers (-1); flush_cached_frames (); } @@ -498,10 +566,15 @@ unwind_to_current_frame (struct ui_out *ui_out, void *args) struct frame_info * get_current_frame (void) { - if (!target_has_stack) - error ("No stack."); + /* First check, and report, the lack of registers. Having GDB + report "No stack!" or "No memory" when the target doesn't even + have registers is very confusing. Besides, "printcmd.exp" + explicitly checks that ``print $pc'' with no registers prints "No + registers". */ if (!target_has_registers) error ("No registers."); + if (!target_has_stack) + error ("No stack."); if (!target_has_memory) error ("No memory."); if (current_frame == NULL) @@ -667,13 +740,6 @@ frame_saved_regs_register_unwind (struct frame_info *frame, void **cache, 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); -} - static void frame_saved_regs_id_unwind (struct frame_info *next_frame, void **cache, struct frame_id *id) @@ -735,17 +801,7 @@ frame_saved_regs_id_unwind (struct frame_info *next_frame, void **cache, id->base = base; } -static void -frame_saved_regs_pop (struct frame_info *fi, void **cache, - struct regcache *regcache) -{ - gdb_assert (POP_FRAME_P ()); - POP_FRAME; -} - const struct frame_unwind trad_frame_unwinder = { - frame_saved_regs_pop, - frame_saved_regs_pc_unwind, frame_saved_regs_id_unwind, frame_saved_regs_register_unwind }; @@ -904,15 +960,15 @@ create_new_frame (CORE_ADDR addr, CORE_ADDR pc) return fi; } -/* Return the frame that FRAME calls (NULL if FRAME is the innermost - frame). Be careful to not fall off the bottom of the frame chain - and onto the sentinel frame. */ +/* Return the frame that THIS_FRAME calls (NULL if THIS_FRAME is the + innermost 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) +get_next_frame (struct frame_info *this_frame) { - if (frame->level > 0) - return frame->next; + if (this_frame->level > 0) + return this_frame->next; else return NULL; } @@ -949,7 +1005,7 @@ reinit_frame_cache (void) INIT_EXTRA_INFO, INIT_FRAME_PC and INIT_FRAME_PC_FIRST. */ static struct frame_info * -legacy_get_prev_frame (struct frame_info *next_frame) +legacy_get_prev_frame (struct frame_info *this_frame) { CORE_ADDR address = 0; struct frame_info *prev; @@ -957,7 +1013,7 @@ legacy_get_prev_frame (struct frame_info *next_frame) /* 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); + gdb_assert (this_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 @@ -966,14 +1022,14 @@ legacy_get_prev_frame (struct frame_info *next_frame) 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 + frame. This macro will set FROMLEAF if THIS_FRAME is a frameless function invocation. */ - if (next_frame->level == 0) + if (this_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 should simply be removed. */ - fromleaf = FRAMELESS_FUNCTION_INVOCATION (next_frame); + fromleaf = FRAMELESS_FUNCTION_INVOCATION (this_frame); else fromleaf = 0; @@ -984,7 +1040,7 @@ legacy_get_prev_frame (struct frame_info *next_frame) /* 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); + address = get_frame_base (this_frame); else { /* Two macros defined in tm.h specify the machine-dependent @@ -1003,9 +1059,9 @@ legacy_get_prev_frame (struct frame_info *next_frame) start go curfluy than have an abort called from main not show main. */ gdb_assert (FRAME_CHAIN_P ()); - address = FRAME_CHAIN (next_frame); + address = FRAME_CHAIN (this_frame); - if (!frame_chain_valid (address, next_frame)) + if (!frame_chain_valid (address, this_frame)) return 0; } if (address == 0) @@ -1015,10 +1071,10 @@ legacy_get_prev_frame (struct frame_info *next_frame) prev = frame_obstack_zalloc (sizeof (struct frame_info)); /* Link it in. */ - next_frame->prev = prev; - prev->next = next_frame; + this_frame->prev = prev; + prev->next = this_frame; prev->frame = address; - prev->level = next_frame->level + 1; + prev->level = this_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 @@ -1083,7 +1139,7 @@ legacy_get_prev_frame (struct frame_info *next_frame) 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 + somewhere (THIS_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. @@ -1112,10 +1168,10 @@ legacy_get_prev_frame (struct frame_info *next_frame) 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) + if (prev->frame == this_frame->frame + && prev->pc == this_frame->pc) { - next_frame->prev = NULL; + this_frame->prev = NULL; obstack_free (&frame_cache_obstack, prev); return NULL; } @@ -1163,11 +1219,11 @@ legacy_get_prev_frame (struct frame_info *next_frame) } /* Return a structure containing various interesting information - about the frame that called NEXT_FRAME. Returns NULL + about the frame that called THIS_FRAME. Returns NULL if there is no such frame. */ struct frame_info * -get_prev_frame (struct frame_info *next_frame) +get_prev_frame (struct frame_info *this_frame) { struct frame_info *prev_frame; @@ -1189,7 +1245,7 @@ get_prev_frame (struct frame_info *next_frame) 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) + if (this_frame == NULL) { /* NOTE: cagney/2002-11-09: There was a code segment here that would error out when CURRENT_FRAME was NULL. The comment @@ -1202,18 +1258,18 @@ get_prev_frame (struct frame_info *next_frame) thing to do.'' Per the above, this code shouldn't even be called with a NULL - NEXT_FRAME. */ + THIS_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); + gdb_assert (this_frame != NULL); - if (next_frame->level >= 0 + if (this_frame->level >= 0 && !backtrace_below_main - && inside_main_func (get_frame_pc (next_frame))) + && inside_main_func (get_frame_pc (this_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 @@ -1226,9 +1282,9 @@ get_prev_frame (struct frame_info *next_frame) } /* Only try to do the unwind once. */ - if (next_frame->prev_p) - return next_frame->prev; - next_frame->prev_p = 1; + if (this_frame->prev_p) + 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 @@ -1241,8 +1297,8 @@ get_prev_frame (struct frame_info *next_frame) /* 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 (next_frame->type != DUMMY_FRAME && next_frame->level >= 0 - && inside_entry_file (get_frame_pc (next_frame))) + if (this_frame->type != DUMMY_FRAME && this_frame->level >= 0 + && inside_entry_file (get_frame_pc (this_frame))) { if (frame_debug) fprintf_unfiltered (gdb_stdlog, @@ -1258,8 +1314,8 @@ get_prev_frame (struct frame_info *next_frame) /* NOTE: cagney/2003-02-25: Don't enable until someone has found hard evidence that this is needed. */ if (0 - && next_frame->type != DUMMY_FRAME && next_frame->level >= 0 - && inside_entry_func (get_frame_pc (next_frame))) + && this_frame->type != DUMMY_FRAME && this_frame->level >= 0 + && inside_entry_func (get_frame_pc (this_frame))) { if (frame_debug) fprintf_unfiltered (gdb_stdlog, @@ -1275,9 +1331,9 @@ get_prev_frame (struct frame_info *next_frame) || DEPRECATED_INIT_FRAME_PC_FIRST_P () || DEPRECATED_INIT_EXTRA_FRAME_INFO_P () || FRAME_CHAIN_P ()) - && next_frame->level >= 0) + && this_frame->level >= 0) { - prev_frame = legacy_get_prev_frame (next_frame); + prev_frame = legacy_get_prev_frame (this_frame); if (frame_debug && prev_frame == NULL) fprintf_unfiltered (gdb_stdlog, "Outermost frame - legacy_get_prev_frame NULL.\n"); @@ -1295,7 +1351,7 @@ get_prev_frame (struct frame_info *next_frame) 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; + prev_frame->level = this_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 @@ -1305,16 +1361,16 @@ get_prev_frame (struct frame_info *next_frame) 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 + THIS_FRAME's data structures have already been initialized (using DEPRECATED_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. */ + using THIS_FRAME's frame ID. */ - prev_frame->pc = frame_pc_unwind (next_frame); + prev_frame->pc = frame_pc_unwind (this_frame); if (prev_frame->pc == 0) { /* The allocated PREV_FRAME will be reclaimed when the frame @@ -1353,9 +1409,9 @@ get_prev_frame (struct frame_info *next_frame) frame_register_unwind to obtain the register values needed to determine the dummy frame's ID. */ prev_frame->id = gdbarch_unwind_dummy_id (current_gdbarch, - next_frame); + this_frame); } - else if (next_frame->level < 0) + else if (this_frame->level < 0) { /* We're unwinding a sentinel frame, the PC of which is pointing at a stack dummy. Fake up the dummy frame's ID @@ -1380,9 +1436,9 @@ get_prev_frame (struct frame_info *next_frame) case SIGTRAMP_FRAME: /* FIXME: cagney/2003-03-04: The below call isn't right. It should instead be doing something like "prev_frame -> unwind - -> id (next_frame, & prev_frame -> unwind_cache, & prev_frame + -> id (this_frame, & prev_frame -> unwind_cache, & prev_frame -> id)" but that requires more extensive (pending) changes. */ - next_frame->unwind->id (next_frame, &next_frame->unwind_cache, + this_frame->unwind->id (this_frame, &this_frame->unwind_cache, &prev_frame->id); /* Check that the unwound ID is valid. */ if (!frame_id_p (prev_frame->id)) @@ -1400,8 +1456,8 @@ get_prev_frame (struct frame_info *next_frame) sentinel frame's frame ID to a `sentinel'. Leave it until after the switch to storing the frame ID, instead of the frame base, in the frame object. */ - if (next_frame->level >= 0 - && frame_id_inner (prev_frame->id, get_frame_id (next_frame))) + if (this_frame->level >= 0 + && frame_id_inner (prev_frame->id, get_frame_id (this_frame))) error ("Unwound frame inner-to selected frame (corrupt stack?)"); /* Note that, due to frameless functions, the stronger test of the new frame being outer to the old frame can't be used - @@ -1418,8 +1474,8 @@ get_prev_frame (struct frame_info *next_frame) prev_frame->frame = prev_frame->id.base; /* Link it in. */ - next_frame->prev = prev_frame; - prev_frame->next = next_frame; + this_frame->prev = prev_frame; + prev_frame->next = this_frame; /* FIXME: cagney/2002-01-19: This call will go away. Instead of initializing extra info, all frames will use the frame_cache @@ -1551,12 +1607,18 @@ deprecated_update_frame_pc_hack (struct frame_info *frame, CORE_ADDR pc) { /* See comment in "frame.h". */ frame->pc = pc; - /* While we're at it, update this frame's cached PC value, found in - the next frame. Oh, for the day when "struct frame_info" is - opaque and this hack on hack can go. */ - gdb_assert (frame->next != NULL); - frame->next->pc_unwind_cache = pc; - frame->next->pc_unwind_cache_p = 1; + /* NOTE: cagney/2003-03-11: Some architectures (e.g., Arm) are + maintaining a locally allocated frame object. Since such frame's + are not in the frame chain, it isn't possible to assume that the + frame has a next. Sigh. */ + if (frame->next != NULL) + { + /* While we're at it, update this frame's cached PC value, found + in the next frame. Oh for the day when "struct frame_info" + is opaque and this hack on hack can just go away. */ + frame->next->pc_unwind_cache = pc; + frame->next->pc_unwind_cache_p = 1; + } } void |