| /* Cache and manage frames for GDB, the GNU debugger. |
| |
| Copyright (C) 1986, 1987, 1989, 1991, 1994, 1995, 1996, 1998, 2000, 2001, |
| 2002, 2003, 2004, 2007, 2008 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 3 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, see <http://www.gnu.org/licenses/>. */ |
| |
| #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 "user-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 "frame-base.h" |
| #include "command.h" |
| #include "gdbcmd.h" |
| #include "observer.h" |
| #include "objfiles.h" |
| #include "exceptions.h" |
| #include "gdbthread.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 |
| points to it. Additional frames get allocated (in get_prev_frame) |
| as needed, and are chained through the next and prev fields. Any |
| time that the frame cache becomes invalid (most notably when we |
| execute something, but also if we change how we interpret the |
| frames (e.g. "set heuristic-fence-post" in mips-tdep.c, or anything |
| which reads new symbols)), we should call reinit_frame_cache. */ |
| |
| struct frame_info |
| { |
| /* Level of this frame. The inner-most (youngest) frame is at level |
| 0. As you move towards the outer-most (oldest) frame, the level |
| increases. This is a cached value. It could just as easily be |
| computed by counting back from the selected frame to the inner |
| most frame. */ |
| /* NOTE: cagney/2002-04-05: Perhaps a level of ``-1'' should be |
| reserved to indicate a bogus frame - one that has been created |
| just to keep GDB happy (GDB always needs a frame). For the |
| moment leave this as speculation. */ |
| int level; |
| |
| /* The frame's low-level unwinder and corresponding cache. The |
| low-level unwinder is responsible for unwinding register values |
| for the previous frame. The low-level unwind methods are |
| selected based on the presence, or otherwise, of register unwind |
| information such as CFI. */ |
| void *prologue_cache; |
| const struct frame_unwind *unwind; |
| |
| /* Cached copy of the previous frame's resume address. */ |
| struct { |
| int p; |
| CORE_ADDR value; |
| } prev_pc; |
| |
| /* Cached copy of the previous frame's function address. */ |
| struct |
| { |
| CORE_ADDR addr; |
| int p; |
| } prev_func; |
| |
| /* This frame's ID. */ |
| struct |
| { |
| int p; |
| struct frame_id value; |
| } this_id; |
| |
| /* The frame's high-level base methods, and corresponding cache. |
| The high level base methods are selected based on the frame's |
| debug info. */ |
| const struct frame_base *base; |
| void *base_cache; |
| |
| /* Pointers to the next (down, inner, younger) and previous (up, |
| outer, older) frame_info's in the frame cache. */ |
| struct frame_info *next; /* down, inner, younger */ |
| int prev_p; |
| struct frame_info *prev; /* up, outer, older */ |
| |
| /* The reason why we could not set PREV, or UNWIND_NO_REASON if we |
| could. Only valid when PREV_P is set. */ |
| enum unwind_stop_reason stop_reason; |
| }; |
| |
| /* Flag to control debugging. */ |
| |
| int frame_debug; |
| static void |
| show_frame_debug (struct ui_file *file, int from_tty, |
| struct cmd_list_element *c, const char *value) |
| { |
| fprintf_filtered (file, _("Frame debugging is %s.\n"), value); |
| } |
| |
| /* Flag to indicate whether backtraces should stop at main et.al. */ |
| |
| static int backtrace_past_main; |
| static void |
| show_backtrace_past_main (struct ui_file *file, int from_tty, |
| struct cmd_list_element *c, const char *value) |
| { |
| fprintf_filtered (file, _("\ |
| Whether backtraces should continue past \"main\" is %s.\n"), |
| value); |
| } |
| |
| static int backtrace_past_entry; |
| static void |
| show_backtrace_past_entry (struct ui_file *file, int from_tty, |
| struct cmd_list_element *c, const char *value) |
| { |
| fprintf_filtered (file, _("\ |
| Whether backtraces should continue past the entry point of a program is %s.\n"), |
| value); |
| } |
| |
| static int backtrace_limit = INT_MAX; |
| static void |
| show_backtrace_limit (struct ui_file *file, int from_tty, |
| struct cmd_list_element *c, const char *value) |
| { |
| fprintf_filtered (file, _("\ |
| An upper bound on the number of backtrace levels is %s.\n"), |
| value); |
| } |
| |
| |
| static void |
| fprint_field (struct ui_file *file, const char *name, int p, CORE_ADDR addr) |
| { |
| if (p) |
| fprintf_unfiltered (file, "%s=0x%s", name, paddr_nz (addr)); |
| else |
| fprintf_unfiltered (file, "!%s", name); |
| } |
| |
| void |
| fprint_frame_id (struct ui_file *file, struct frame_id id) |
| { |
| fprintf_unfiltered (file, "{"); |
| fprint_field (file, "stack", id.stack_addr_p, id.stack_addr); |
| fprintf_unfiltered (file, ","); |
| fprint_field (file, "code", id.code_addr_p, id.code_addr); |
| fprintf_unfiltered (file, ","); |
| fprint_field (file, "special", id.special_addr_p, id.special_addr); |
| fprintf_unfiltered (file, "}"); |
| } |
| |
| static void |
| fprint_frame_type (struct ui_file *file, enum frame_type type) |
| { |
| switch (type) |
| { |
| case NORMAL_FRAME: |
| fprintf_unfiltered (file, "NORMAL_FRAME"); |
| return; |
| case DUMMY_FRAME: |
| fprintf_unfiltered (file, "DUMMY_FRAME"); |
| return; |
| case SIGTRAMP_FRAME: |
| fprintf_unfiltered (file, "SIGTRAMP_FRAME"); |
| return; |
| default: |
| fprintf_unfiltered (file, "<unknown type>"); |
| return; |
| }; |
| } |
| |
| static void |
| fprint_frame (struct ui_file *file, struct frame_info *fi) |
| { |
| if (fi == NULL) |
| { |
| fprintf_unfiltered (file, "<NULL frame>"); |
| return; |
| } |
| fprintf_unfiltered (file, "{"); |
| fprintf_unfiltered (file, "level=%d", fi->level); |
| fprintf_unfiltered (file, ","); |
| fprintf_unfiltered (file, "type="); |
| if (fi->unwind != NULL) |
| fprint_frame_type (file, fi->unwind->type); |
| else |
| fprintf_unfiltered (file, "<unknown>"); |
| fprintf_unfiltered (file, ","); |
| fprintf_unfiltered (file, "unwind="); |
| if (fi->unwind != NULL) |
| gdb_print_host_address (fi->unwind, file); |
| else |
| fprintf_unfiltered (file, "<unknown>"); |
| fprintf_unfiltered (file, ","); |
| fprintf_unfiltered (file, "pc="); |
| if (fi->next != NULL && fi->next->prev_pc.p) |
| fprintf_unfiltered (file, "0x%s", paddr_nz (fi->next->prev_pc.value)); |
| else |
| fprintf_unfiltered (file, "<unknown>"); |
| fprintf_unfiltered (file, ","); |
| fprintf_unfiltered (file, "id="); |
| if (fi->this_id.p) |
| fprint_frame_id (file, fi->this_id.value); |
| else |
| fprintf_unfiltered (file, "<unknown>"); |
| fprintf_unfiltered (file, ","); |
| fprintf_unfiltered (file, "func="); |
| if (fi->next != NULL && fi->next->prev_func.p) |
| fprintf_unfiltered (file, "0x%s", paddr_nz (fi->next->prev_func.addr)); |
| else |
| fprintf_unfiltered (file, "<unknown>"); |
| fprintf_unfiltered (file, "}"); |
| } |
| |
| /* 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; |
| } |
| if (!fi->this_id.p) |
| { |
| if (frame_debug) |
| fprintf_unfiltered (gdb_stdlog, "{ get_frame_id (fi=%d) ", |
| fi->level); |
| /* Find the unwinder. */ |
| if (fi->unwind == NULL) |
| fi->unwind = frame_unwind_find_by_frame (fi, &fi->prologue_cache); |
| /* Find THIS frame's ID. */ |
| fi->unwind->this_id (fi, &fi->prologue_cache, &fi->this_id.value); |
| fi->this_id.p = 1; |
| if (frame_debug) |
| { |
| fprintf_unfiltered (gdb_stdlog, "-> "); |
| fprint_frame_id (gdb_stdlog, fi->this_id.value); |
| fprintf_unfiltered (gdb_stdlog, " }\n"); |
| } |
| } |
| 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 |
| frame_id_build_special (CORE_ADDR stack_addr, CORE_ADDR code_addr, |
| CORE_ADDR special_addr) |
| { |
| struct frame_id id = null_frame_id; |
| id.stack_addr = stack_addr; |
| id.stack_addr_p = 1; |
| id.code_addr = code_addr; |
| id.code_addr_p = 1; |
| id.special_addr = special_addr; |
| id.special_addr_p = 1; |
| return id; |
| } |
| |
| struct frame_id |
| frame_id_build (CORE_ADDR stack_addr, CORE_ADDR code_addr) |
| { |
| struct frame_id id = null_frame_id; |
| id.stack_addr = stack_addr; |
| id.stack_addr_p = 1; |
| id.code_addr = code_addr; |
| id.code_addr_p = 1; |
| return id; |
| } |
| |
| struct frame_id |
| frame_id_build_wild (CORE_ADDR stack_addr) |
| { |
| struct frame_id id = null_frame_id; |
| id.stack_addr = stack_addr; |
| id.stack_addr_p = 1; |
| return id; |
| } |
| |
| int |
| frame_id_p (struct frame_id l) |
| { |
| int p; |
| /* The frame is valid iff it has a valid stack address. */ |
| p = l.stack_addr_p; |
| if (frame_debug) |
| { |
| fprintf_unfiltered (gdb_stdlog, "{ frame_id_p (l="); |
| fprint_frame_id (gdb_stdlog, l); |
| fprintf_unfiltered (gdb_stdlog, ") -> %d }\n", p); |
| } |
| return p; |
| } |
| |
| int |
| frame_id_eq (struct frame_id l, struct frame_id r) |
| { |
| int eq; |
| if (!l.stack_addr_p || !r.stack_addr_p) |
| /* Like a NaN, if either ID is invalid, the result is false. |
| Note that a frame ID is invalid iff it is the null frame ID. */ |
| eq = 0; |
| else if (l.stack_addr != r.stack_addr) |
| /* If .stack addresses are different, the frames are different. */ |
| eq = 0; |
| else if (!l.code_addr_p || !r.code_addr_p) |
| /* An invalid code addr is a wild card, always succeed. */ |
| eq = 1; |
| else if (l.code_addr != r.code_addr) |
| /* If .code addresses are different, the frames are different. */ |
| eq = 0; |
| else if (!l.special_addr_p || !r.special_addr_p) |
| /* An invalid special addr is a wild card (or unused), always succeed. */ |
| eq = 1; |
| else if (l.special_addr == r.special_addr) |
| /* Frames are equal. */ |
| eq = 1; |
| else |
| /* No luck. */ |
| eq = 0; |
| if (frame_debug) |
| { |
| fprintf_unfiltered (gdb_stdlog, "{ frame_id_eq (l="); |
| fprint_frame_id (gdb_stdlog, l); |
| fprintf_unfiltered (gdb_stdlog, ",r="); |
| fprint_frame_id (gdb_stdlog, r); |
| fprintf_unfiltered (gdb_stdlog, ") -> %d }\n", eq); |
| } |
| return eq; |
| } |
| |
| /* 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; |
| if (!l.stack_addr_p || !r.stack_addr_p) |
| /* Like NaN, any operation involving an invalid ID always fails. */ |
| inner = 0; |
| else |
| /* 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 .stack but |
| different .code and/or .special address). */ |
| inner = gdbarch_inner_than (gdbarch, l.stack_addr, r.stack_addr); |
| if (frame_debug) |
| { |
| fprintf_unfiltered (gdb_stdlog, "{ frame_id_inner (l="); |
| fprint_frame_id (gdb_stdlog, l); |
| fprintf_unfiltered (gdb_stdlog, ",r="); |
| fprint_frame_id (gdb_stdlog, r); |
| fprintf_unfiltered (gdb_stdlog, ") -> %d }\n", inner); |
| } |
| return inner; |
| } |
| |
| struct frame_info * |
| frame_find_by_id (struct frame_id id) |
| { |
| 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 = prev_frame) |
| { |
| struct frame_id this = get_frame_id (frame); |
| if (frame_id_eq (id, this)) |
| /* An exact match. */ |
| return frame; |
| |
| 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; |
| } |
| return NULL; |
| } |
| |
| CORE_ADDR |
| frame_pc_unwind (struct frame_info *this_frame) |
| { |
| if (!this_frame->prev_pc.p) |
| { |
| CORE_ADDR pc; |
| if (gdbarch_unwind_pc_p (get_frame_arch (this_frame))) |
| { |
| /* 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_unsigned_integer (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 (get_frame_arch (this_frame), this_frame); |
| } |
| else |
| internal_error (__FILE__, __LINE__, _("No unwind_pc method")); |
| this_frame->prev_pc.value = pc; |
| this_frame->prev_pc.p = 1; |
| if (frame_debug) |
| fprintf_unfiltered (gdb_stdlog, |
| "{ frame_pc_unwind (this_frame=%d) -> 0x%s }\n", |
| this_frame->level, |
| paddr_nz (this_frame->prev_pc.value)); |
| } |
| return this_frame->prev_pc.value; |
| } |
| |
| CORE_ADDR |
| get_frame_func (struct frame_info *this_frame) |
| { |
| struct frame_info *next_frame = this_frame->next; |
| |
| if (!next_frame->prev_func.p) |
| { |
| /* Make certain that this, and not the adjacent, function is |
| found. */ |
| CORE_ADDR addr_in_block = get_frame_address_in_block (this_frame); |
| next_frame->prev_func.p = 1; |
| next_frame->prev_func.addr = get_pc_function_start (addr_in_block); |
| if (frame_debug) |
| fprintf_unfiltered (gdb_stdlog, |
| "{ get_frame_func (this_frame=%d) -> 0x%s }\n", |
| this_frame->level, |
| paddr_nz (next_frame->prev_func.addr)); |
| } |
| return next_frame->prev_func.addr; |
| } |
| |
| static int |
| do_frame_register_read (void *src, int regnum, gdb_byte *buf) |
| { |
| return frame_register_read (src, regnum, buf); |
| } |
| |
| struct regcache * |
| frame_save_as_regcache (struct frame_info *this_frame) |
| { |
| struct regcache *regcache = regcache_xmalloc (get_frame_arch (this_frame)); |
| struct cleanup *cleanups = make_cleanup_regcache_xfree (regcache); |
| regcache_save (regcache, do_frame_register_read, this_frame); |
| discard_cleanups (cleanups); |
| return regcache; |
| } |
| |
| void |
| frame_pop (struct frame_info *this_frame) |
| { |
| struct frame_info *prev_frame; |
| struct regcache *scratch; |
| struct cleanup *cleanups; |
| |
| /* Ensure that we have a frame to pop to. */ |
| prev_frame = get_prev_frame_1 (this_frame); |
| |
| if (!prev_frame) |
| error (_("Cannot pop the initial frame.")); |
| |
| /* 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 between |
| trying to extract the old values from the current regcache while |
| at the same time writing new values into that same cache. */ |
| 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 |
| be batched. The pair target_prepare_to_store() and |
| target_store_registers() kind of suggest this functionality. |
| Unfortunately, they don't implement it. Their lack of a formal |
| definition can lead to targets writing back bogus values |
| (arguably a bug in the target code mind). */ |
| /* Now copy those saved registers into the current regcache. |
| Here, regcache_cpy() calls regcache_restore(). */ |
| regcache_cpy (get_current_regcache (), scratch); |
| do_cleanups (cleanups); |
| |
| /* We've made right mess of GDB's local state, just discard |
| everything. */ |
| reinit_frame_cache (); |
| } |
| |
| void |
| frame_register_unwind (struct frame_info *frame, int regnum, |
| int *optimizedp, enum lval_type *lvalp, |
| CORE_ADDR *addrp, int *realnump, gdb_byte *bufferp) |
| { |
| struct value *value; |
| |
| /* 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); */ |
| |
| value = frame_unwind_register_value (frame, regnum); |
| |
| gdb_assert (value != NULL); |
| |
| *optimizedp = value_optimized_out (value); |
| *lvalp = VALUE_LVAL (value); |
| *addrp = VALUE_ADDRESS (value); |
| *realnump = VALUE_REGNUM (value); |
| |
| if (bufferp) |
| memcpy (bufferp, value_contents_all (value), |
| TYPE_LENGTH (value_type (value))); |
| |
| /* Dispose of the new value. This prevents watchpoints from |
| trying to watch the saved frame pointer. */ |
| release_value (value); |
| value_free (value); |
| } |
| |
| void |
| frame_register (struct frame_info *frame, int regnum, |
| int *optimizedp, enum lval_type *lvalp, |
| CORE_ADDR *addrp, int *realnump, gdb_byte *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); */ |
| |
| /* 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_register (struct frame_info *frame, int regnum, gdb_byte *buf) |
| { |
| int optimized; |
| CORE_ADDR addr; |
| int realnum; |
| enum lval_type lval; |
| frame_register_unwind (frame, regnum, &optimized, &lval, &addr, |
| &realnum, buf); |
| } |
| |
| void |
| get_frame_register (struct frame_info *frame, |
| int regnum, gdb_byte *buf) |
| { |
| frame_unwind_register (frame->next, regnum, buf); |
| } |
| |
| struct value * |
| frame_unwind_register_value (struct frame_info *frame, int regnum) |
| { |
| struct value *value; |
| |
| gdb_assert (frame != NULL); |
| |
| if (frame_debug) |
| { |
| fprintf_unfiltered (gdb_stdlog, "\ |
| { frame_unwind_register_value (frame=%d,regnum=%d(%s),...) ", |
| frame->level, regnum, |
| user_reg_map_regnum_to_name |
| (get_frame_arch (frame), regnum)); |
| } |
| |
| /* Find the unwinder. */ |
| if (frame->unwind == NULL) |
| frame->unwind = frame_unwind_find_by_frame (frame, &frame->prologue_cache); |
| |
| /* Ask this frame to unwind its register. */ |
| value = frame->unwind->prev_register (frame, &frame->prologue_cache, regnum); |
| |
| if (frame_debug) |
| { |
| fprintf_unfiltered (gdb_stdlog, "->"); |
| if (value_optimized_out (value)) |
| fprintf_unfiltered (gdb_stdlog, " optimized out"); |
| else |
| { |
| if (VALUE_LVAL (value) == lval_register) |
| fprintf_unfiltered (gdb_stdlog, " register=%d", |
| VALUE_REGNUM (value)); |
| else if (VALUE_LVAL (value) == lval_memory) |
| fprintf_unfiltered (gdb_stdlog, " address=0x%s", |
| paddr_nz (VALUE_ADDRESS (value))); |
| else |
| fprintf_unfiltered (gdb_stdlog, " computed"); |
| |
| if (value_lazy (value)) |
| fprintf_unfiltered (gdb_stdlog, " lazy"); |
| else |
| { |
| int i; |
| const gdb_byte *buf = value_contents (value); |
| |
| fprintf_unfiltered (gdb_stdlog, " bytes="); |
| fprintf_unfiltered (gdb_stdlog, "["); |
| for (i = 0; i < register_size (get_frame_arch (frame), regnum); i++) |
| fprintf_unfiltered (gdb_stdlog, "%02x", buf[i]); |
| fprintf_unfiltered (gdb_stdlog, "]"); |
| } |
| } |
| |
| fprintf_unfiltered (gdb_stdlog, " }\n"); |
| } |
| |
| return value; |
| } |
| |
| struct value * |
| get_frame_register_value (struct frame_info *frame, int regnum) |
| { |
| return frame_unwind_register_value (frame->next, regnum); |
| } |
| |
| LONGEST |
| frame_unwind_register_signed (struct frame_info *frame, int regnum) |
| { |
| gdb_byte buf[MAX_REGISTER_SIZE]; |
| frame_unwind_register (frame, regnum, buf); |
| return extract_signed_integer (buf, register_size (get_frame_arch (frame), |
| regnum)); |
| } |
| |
| LONGEST |
| get_frame_register_signed (struct frame_info *frame, int regnum) |
| { |
| return frame_unwind_register_signed (frame->next, regnum); |
| } |
| |
| ULONGEST |
| frame_unwind_register_unsigned (struct frame_info *frame, int regnum) |
| { |
| gdb_byte buf[MAX_REGISTER_SIZE]; |
| frame_unwind_register (frame, regnum, buf); |
| return extract_unsigned_integer (buf, register_size (get_frame_arch (frame), |
| regnum)); |
| } |
| |
| ULONGEST |
| get_frame_register_unsigned (struct frame_info *frame, int regnum) |
| { |
| return frame_unwind_register_unsigned (frame->next, regnum); |
| } |
| |
| void |
| put_frame_register (struct frame_info *frame, int regnum, |
| const gdb_byte *buf) |
| { |
| struct gdbarch *gdbarch = get_frame_arch (frame); |
| int realnum; |
| int optim; |
| enum lval_type lval; |
| CORE_ADDR addr; |
| frame_register (frame, regnum, &optim, &lval, &addr, &realnum, NULL); |
| if (optim) |
| error (_("Attempt to assign to a value that was optimized out.")); |
| switch (lval) |
| { |
| case lval_memory: |
| { |
| /* FIXME: write_memory doesn't yet take constant buffers. |
| Arrrg! */ |
| gdb_byte tmp[MAX_REGISTER_SIZE]; |
| memcpy (tmp, buf, register_size (gdbarch, regnum)); |
| write_memory (addr, tmp, register_size (gdbarch, regnum)); |
| break; |
| } |
| case lval_register: |
| regcache_cooked_write (get_current_regcache (), realnum, buf); |
| break; |
| default: |
| error (_("Attempt to assign to an unmodifiable value.")); |
| } |
| } |
| |
| /* frame_register_read () |
| |
| Find and return the value of REGNUM for the specified stack frame. |
| The number of bytes copied is REGISTER_SIZE (REGNUM). |
| |
| Returns 0 if the register value could not be found. */ |
| |
| int |
| frame_register_read (struct frame_info *frame, int regnum, |
| gdb_byte *myaddr) |
| { |
| int optimized; |
| enum lval_type lval; |
| CORE_ADDR addr; |
| int realnum; |
| frame_register (frame, regnum, &optimized, &lval, &addr, &realnum, myaddr); |
| |
| return !optimized; |
| } |
| |
| int |
| get_frame_register_bytes (struct frame_info *frame, int regnum, |
| CORE_ADDR offset, int len, gdb_byte *myaddr) |
| { |
| struct gdbarch *gdbarch = get_frame_arch (frame); |
| int i; |
| int maxsize; |
| int numregs; |
| |
| /* Skip registers wholly inside of OFFSET. */ |
| while (offset >= register_size (gdbarch, regnum)) |
| { |
| offset -= register_size (gdbarch, regnum); |
| regnum++; |
| } |
| |
| /* Ensure that we will not read beyond the end of the register file. |
| This can only ever happen if the debug information is bad. */ |
| maxsize = -offset; |
| numregs = gdbarch_num_regs (gdbarch) + gdbarch_num_pseudo_regs (gdbarch); |
| for (i = regnum; i < numregs; i++) |
| { |
| int thissize = register_size (gdbarch, i); |
| if (thissize == 0) |
| break; /* This register is not available on this architecture. */ |
| maxsize += thissize; |
| } |
| if (len > maxsize) |
| { |
| warning (_("Bad debug information detected: " |
| "Attempt to read %d bytes from registers."), len); |
| return 0; |
| } |
| |
| /* Copy the data. */ |
| while (len > 0) |
| { |
| int curr_len = register_size (gdbarch, regnum) - offset; |
| if (curr_len > len) |
| curr_len = len; |
| |
| if (curr_len == register_size (gdbarch, regnum)) |
| { |
| if (!frame_register_read (frame, regnum, myaddr)) |
| return 0; |
| } |
| else |
| { |
| gdb_byte buf[MAX_REGISTER_SIZE]; |
| if (!frame_register_read (frame, regnum, buf)) |
| return 0; |
| memcpy (myaddr, buf + offset, curr_len); |
| } |
| |
| myaddr += curr_len; |
| len -= curr_len; |
| offset = 0; |
| regnum++; |
| } |
| |
| return 1; |
| } |
| |
| void |
| put_frame_register_bytes (struct frame_info *frame, int regnum, |
| CORE_ADDR offset, int len, const gdb_byte *myaddr) |
| { |
| struct gdbarch *gdbarch = get_frame_arch (frame); |
| |
| /* Skip registers wholly inside of OFFSET. */ |
| while (offset >= register_size (gdbarch, regnum)) |
| { |
| offset -= register_size (gdbarch, regnum); |
| regnum++; |
| } |
| |
| /* Copy the data. */ |
| while (len > 0) |
| { |
| int curr_len = register_size (gdbarch, regnum) - offset; |
| if (curr_len > len) |
| curr_len = len; |
| |
| if (curr_len == register_size (gdbarch, regnum)) |
| { |
| put_frame_register (frame, regnum, myaddr); |
| } |
| else |
| { |
| gdb_byte buf[MAX_REGISTER_SIZE]; |
| frame_register_read (frame, regnum, buf); |
| memcpy (buf + offset, myaddr, curr_len); |
| put_frame_register (frame, regnum, buf); |
| } |
| |
| myaddr += curr_len; |
| len -= curr_len; |
| offset = 0; |
| regnum++; |
| } |
| } |
| |
| /* Create a sentinel frame. */ |
| |
| static struct frame_info * |
| create_sentinel_frame (struct regcache *regcache) |
| { |
| struct frame_info *frame = FRAME_OBSTACK_ZALLOC (struct frame_info); |
| 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->prologue_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; |
| /* Make the sentinel frame's ID valid, but invalid. That way all |
| comparisons with it should fail. */ |
| frame->this_id.p = 1; |
| frame->this_id.value = null_frame_id; |
| if (frame_debug) |
| { |
| fprintf_unfiltered (gdb_stdlog, "{ create_sentinel_frame (...) -> "); |
| fprint_frame (gdb_stdlog, frame); |
| fprintf_unfiltered (gdb_stdlog, " }\n"); |
| } |
| return frame; |
| } |
| |
| /* 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_zalloc (unsigned long size) |
| { |
| void *data = obstack_alloc (&frame_cache_obstack, size); |
| memset (data, 0, size); |
| return data; |
| } |
| |
| /* 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, e.g., because its PC value |
| lands in somewhere like start. */ |
| if (frame == NULL) |
| return 1; |
| current_frame = frame; |
| return 0; |
| } |
| |
| struct frame_info * |
| get_current_frame (void) |
| { |
| /* 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 (is_executing (inferior_ptid)) |
| error (_("Target is executing.")); |
| |
| if (current_frame == NULL) |
| { |
| struct frame_info *sentinel_frame = |
| create_sentinel_frame (get_current_regcache ()); |
| if (catch_exceptions (uiout, unwind_to_current_frame, sentinel_frame, |
| 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; |
| } |
| |
| /* The "selected" stack frame is used by default for local and arg |
| access. May be zero, for no selected frame. */ |
| |
| static struct frame_info *selected_frame; |
| |
| static int |
| has_stack_frames (void) |
| { |
| if (!target_has_registers || !target_has_stack || !target_has_memory) |
| return 0; |
| |
| /* If the current thread is executing, don't try to read from |
| it. */ |
| if (is_executing (inferior_ptid)) |
| return 0; |
| |
| return 1; |
| } |
| |
| /* 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 (const char *message) |
| { |
| if (selected_frame == NULL) |
| { |
| if (message != NULL && !has_stack_frames ()) |
| error (("%s"), message); |
| /* 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 (selected_frame != NULL); |
| return selected_frame; |
| } |
| |
| /* This is a variant of get_selected_frame() which can be called when |
| the inferior does not have a frame; in that case it will return |
| NULL instead of calling error(). */ |
| |
| struct frame_info * |
| deprecated_safe_get_selected_frame (void) |
| { |
| if (!has_stack_frames ()) |
| return NULL; |
| return get_selected_frame (NULL); |
| } |
| |
| /* Select frame FI (or NULL - to invalidate the current frame). */ |
| |
| void |
| select_frame (struct frame_info *fi) |
| { |
| struct symtab *s; |
| |
| selected_frame = fi; |
| /* NOTE: cagney/2002-05-04: FI can be NULL. This occurs when the |
| frame is being invalidated. */ |
| if (deprecated_selected_frame_level_changed_hook) |
| deprecated_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 user's 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) |
| { |
| /* We retrieve the frame's symtab by using the frame PC. However |
| we cannot use the frame PC as-is, because it usually points to |
| the instruction following the "call", which is sometimes the |
| first instruction of another function. So we rely on |
| get_frame_address_in_block() which provides us with a PC which |
| is guaranteed to be inside the frame's code block. */ |
| s = find_pc_symtab (get_frame_address_in_block (fi)); |
| if (s |
| && s->language != current_language->la_language |
| && s->language != language_unknown |
| && language_mode == language_mode_auto) |
| { |
| set_language (s->language); |
| } |
| } |
| } |
| |
| /* 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; |
| |
| if (frame_debug) |
| { |
| fprintf_unfiltered (gdb_stdlog, |
| "{ create_new_frame (addr=0x%s, pc=0x%s) ", |
| paddr_nz (addr), paddr_nz (pc)); |
| } |
| |
| fi = FRAME_OBSTACK_ZALLOC (struct frame_info); |
| |
| fi->next = create_sentinel_frame (get_current_regcache ()); |
| |
| /* Select/initialize both the unwind function and the frame's type |
| based on the PC. */ |
| fi->unwind = frame_unwind_find_by_frame (fi, &fi->prologue_cache); |
| |
| fi->this_id.p = 1; |
| deprecated_update_frame_base_hack (fi, addr); |
| deprecated_update_frame_pc_hack (fi, pc); |
| |
| if (frame_debug) |
| { |
| fprintf_unfiltered (gdb_stdlog, "-> "); |
| fprint_frame (gdb_stdlog, fi); |
| fprintf_unfiltered (gdb_stdlog, " }\n"); |
| } |
| |
| return fi; |
| } |
| |
| /* 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 *this_frame) |
| { |
| if (this_frame->level > 0) |
| return this_frame->next; |
| else |
| return NULL; |
| } |
| |
| /* Observer for the target_changed event. */ |
| |
| void |
| frame_observer_target_changed (struct target_ops *target) |
| { |
| reinit_frame_cache (); |
| } |
| |
| /* Flush the entire frame cache. */ |
| |
| void |
| reinit_frame_cache (void) |
| { |
| struct frame_info *fi; |
| |
| /* Tear down all frame caches. */ |
| for (fi = current_frame; fi != NULL; fi = fi->prev) |
| { |
| if (fi->prologue_cache && fi->unwind->dealloc_cache) |
| fi->unwind->dealloc_cache (fi, fi->prologue_cache); |
| if (fi->base_cache && fi->base->unwind->dealloc_cache) |
| fi->base->unwind->dealloc_cache (fi, fi->base_cache); |
| } |
| |
| /* Since we can't really be sure what the first object allocated was */ |
| obstack_free (&frame_cache_obstack, 0); |
| obstack_init (&frame_cache_obstack); |
| |
| if (current_frame != NULL) |
| annotate_frames_invalid (); |
| |
| current_frame = NULL; /* Invalidate cache */ |
| select_frame (NULL); |
| if (frame_debug) |
| fprintf_unfiltered (gdb_stdlog, "{ reinit_frame_cache () }\n"); |
| } |
| |
| /* Find where a register is saved (in memory or another register). |
| The result of frame_register_unwind is just where it is saved |
| relative to this particular frame. */ |
| |
| static void |
| frame_register_unwind_location (struct frame_info *this_frame, int regnum, |
| int *optimizedp, enum lval_type *lvalp, |
| CORE_ADDR *addrp, int *realnump) |
| { |
| gdb_assert (this_frame == NULL || this_frame->level >= 0); |
| |
| while (this_frame != NULL) |
| { |
| frame_register_unwind (this_frame, regnum, optimizedp, lvalp, |
| addrp, realnump, NULL); |
| |
| if (*optimizedp) |
| break; |
| |
| if (*lvalp != lval_register) |
| break; |
| |
| regnum = *realnump; |
| this_frame = get_next_frame (this_frame); |
| } |
| } |
| |
| /* Return a "struct frame_info" corresponding to the frame that called |
| THIS_FRAME. Returns NULL if there is no such frame. |
| |
| Unlike get_prev_frame, this function always tries to unwind the |
| frame. */ |
| |
| static struct frame_info * |
| get_prev_frame_1 (struct frame_info *this_frame) |
| { |
| struct frame_info *prev_frame; |
| struct frame_id this_id; |
| struct gdbarch *gdbarch; |
| |
| gdb_assert (this_frame != NULL); |
| gdbarch = get_frame_arch (this_frame); |
| |
| if (frame_debug) |
| { |
| fprintf_unfiltered (gdb_stdlog, "{ get_prev_frame_1 (this_frame="); |
| if (this_frame != NULL) |
| fprintf_unfiltered (gdb_stdlog, "%d", this_frame->level); |
| else |
| fprintf_unfiltered (gdb_stdlog, "<NULL>"); |
| 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; |
| } |
| |
| /* If the frame unwinder hasn't been selected yet, we must do so |
| before setting prev_p; otherwise the check for misbehaved |
| sniffers will think that this frame's sniffer tried to unwind |
| further (see frame_cleanup_after_sniffer). */ |
| if (this_frame->unwind == NULL) |
| this_frame->unwind |
| = frame_unwind_find_by_frame (this_frame, &this_frame->prologue_cache); |
| |
| this_frame->prev_p = 1; |
| this_frame->stop_reason = UNWIND_NO_REASON; |
| |
| /* 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. */ |
| this_id = get_frame_id (this_frame); |
| if (this_frame->level >= 0 && !frame_id_p (this_id)) |
| { |
| if (frame_debug) |
| { |
| fprintf_unfiltered (gdb_stdlog, "-> "); |
| fprint_frame (gdb_stdlog, NULL); |
| fprintf_unfiltered (gdb_stdlog, " // this ID is NULL }\n"); |
| } |
| this_frame->stop_reason = UNWIND_NULL_ID; |
| 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. |
| 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) |
| { |
| fprintf_unfiltered (gdb_stdlog, "-> "); |
| fprint_frame (gdb_stdlog, NULL); |
| fprintf_unfiltered (gdb_stdlog, " // this frame ID is inner }\n"); |
| } |
| this_frame->stop_reason = UNWIND_INNER_ID; |
| return NULL; |
| } |
| |
| /* 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 (this_id, get_frame_id (this_frame->next))) |
| { |
| if (frame_debug) |
| { |
| fprintf_unfiltered (gdb_stdlog, "-> "); |
| fprint_frame (gdb_stdlog, NULL); |
| fprintf_unfiltered (gdb_stdlog, " // this frame has same ID }\n"); |
| } |
| this_frame->stop_reason = UNWIND_SAME_ID; |
| return NULL; |
| } |
| |
| /* Check that this and the next frame do not unwind the PC register |
| to the same memory location. If they do, then even though they |
| have different frame IDs, the new frame will be bogus; two |
| functions can't share a register save slot for the PC. This can |
| happen when the prologue analyzer finds a stack adjustment, but |
| no PC save. |
| |
| This check does assume that the "PC register" is roughly a |
| traditional PC, even if the gdbarch_unwind_pc method adjusts |
| it (we do not rely on the value, only on the unwound PC being |
| dependent on this value). A potential improvement would be |
| to have the frame prev_pc method and the gdbarch unwind_pc |
| method set the same lval and location information as |
| frame_register_unwind. */ |
| if (this_frame->level > 0 |
| && gdbarch_pc_regnum (gdbarch) >= 0 |
| && get_frame_type (this_frame) == NORMAL_FRAME |
| && get_frame_type (this_frame->next) == NORMAL_FRAME) |
| { |
| int optimized, realnum, nrealnum; |
| enum lval_type lval, nlval; |
| CORE_ADDR addr, naddr; |
| |
| frame_register_unwind_location (this_frame, |
| gdbarch_pc_regnum (gdbarch), |
| &optimized, &lval, &addr, &realnum); |
| frame_register_unwind_location (get_next_frame (this_frame), |
| gdbarch_pc_regnum (gdbarch), |
| &optimized, &nlval, &naddr, &nrealnum); |
| |
| if ((lval == lval_memory && lval == nlval && addr == naddr) |
| || (lval == lval_register && lval == nlval && realnum == nrealnum)) |
| { |
| if (frame_debug) |
| { |
| fprintf_unfiltered (gdb_stdlog, "-> "); |
| fprint_frame (gdb_stdlog, NULL); |
| fprintf_unfiltered (gdb_stdlog, " // no saved PC }\n"); |
| } |
| |
| this_frame->stop_reason = UNWIND_NO_SAVED_PC; |
| this_frame->prev = NULL; |
| return NULL; |
| } |
| } |
| |
| /* 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); |
| } |
| } |
| |
| /* Is this (non-sentinel) frame in the "main"() function? */ |
| |
| static int |
| inside_main_func (struct frame_info *this_frame) |
| { |
| struct minimal_symbol *msymbol; |
| CORE_ADDR maddr; |
| |
| if (symfile_objfile == 0) |
| return 0; |
| msymbol = lookup_minimal_symbol (main_name (), NULL, symfile_objfile); |
| if (msymbol == NULL) |
| return 0; |
| /* Make certain that the code, and not descriptor, address is |
| returned. */ |
| maddr = gdbarch_convert_from_func_ptr_addr (get_frame_arch (this_frame), |
| SYMBOL_VALUE_ADDRESS (msymbol), |
| ¤t_target); |
| return maddr == get_frame_func (this_frame); |
| } |
| |
| /* Test whether THIS_FRAME is inside the process entry point function. */ |
| |
| static int |
| inside_entry_func (struct frame_info *this_frame) |
| { |
| return (get_frame_func (this_frame) == entry_point_address ()); |
| } |
| |
| /* 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 |
| 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 in |
| block_innermost_frame() is, when the target has no state |
| (registers, memory, ...), it is 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 (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 |
| 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 |
| THIS_FRAME. */ |
| frame_debug_got_null_frame (gdb_stdlog, this_frame, "this_frame NULL"); |
| 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 (this_frame != NULL); |
| |
| /* tausq/2004-12-07: Dummy frames are skipped because it doesn't make much |
| sense to stop unwinding at a dummy frame. One place where a dummy |
| frame may have an address "inside_main_func" is on HPUX. On HPUX, the |
| pcsqh register (space register for the instruction at the head of the |
| instruction queue) cannot be written directly; the only way to set it |
| is to branch to code that is in the target space. In order to implement |
| frame dummies on HPUX, the called function is made to jump back to where |
| the inferior was when the user function was called. If gdb was inside |
| the main function when we created the dummy frame, the dummy frame will |
| point inside the main function. */ |
| if (this_frame->level >= 0 |
| && get_frame_type (this_frame) != DUMMY_FRAME |
| && !backtrace_past_main |
| && inside_main_func (this_frame)) |
| /* Don't unwind past main(). Note, this is done _before_ the |
| frame has been marked as previously unwound. That way if the |
| user later decides to enable unwinds past main(), that will |
| automatically happen. */ |
| { |
| frame_debug_got_null_frame (gdb_stdlog, this_frame, "inside main func"); |
| return NULL; |
| } |
| |
| /* If the user's backtrace limit has been exceeded, stop. We must |
| add two to the current level; one of those accounts for backtrace_limit |
| being 1-based and the level being 0-based, and the other accounts for |
| the level of the new frame instead of the level of the current |
| frame. */ |
| if (this_frame->level + 2 > backtrace_limit) |
| { |
| frame_debug_got_null_frame (gdb_stdlog, this_frame, |
| "backtrace limit exceeded"); |
| return NULL; |
| } |
| |
| /* If we're already inside the entry function for the main objfile, |
| then it isn't valid. Don't apply this test to a dummy frame - |
| dummy frame PCs typically land in the entry func. Don't apply |
| this test to the sentinel frame. Sentinel frames should always |
| be allowed to unwind. */ |
| /* NOTE: cagney/2003-07-07: Fixed a bug in inside_main_func() - |
| wasn't checking for "main" in the minimal symbols. With that |
| fixed asm-source tests now stop in "main" instead of halting the |
| backtrace in weird and wonderful ways somewhere inside the entry |
| file. Suspect that tests for inside the entry file/func were |
| added to work around that (now fixed) case. */ |
| /* NOTE: cagney/2003-07-15: danielj (if I'm reading it right) |
| suggested having the inside_entry_func test use the |
| inside_main_func() msymbol trick (along with entry_point_address() |
| I guess) to determine the address range of the start function. |
| That should provide a far better stopper than the current |
| heuristics. */ |
| /* NOTE: tausq/2004-10-09: this is needed if, for example, the compiler |
| applied tail-call optimizations to main so that a function called |
| from main returns directly to the caller of main. Since we don't |
| stop at main, we should at least stop at the entry point of the |
| application. */ |
| if (!backtrace_past_entry |
| && get_frame_type (this_frame) != DUMMY_FRAME && this_frame->level >= 0 |
| && inside_entry_func (this_frame)) |
| { |
| frame_debug_got_null_frame (gdb_stdlog, this_frame, "inside entry func"); |
| return NULL; |
| } |
| |
| /* Assume that the only way to get a zero PC is through something |
| like a SIGSEGV or a dummy frame, and hence that NORMAL frames |
| will never unwind a zero PC. */ |
| if (this_frame->level > 0 |
| && get_frame_type (this_frame) == NORMAL_FRAME |
| && get_frame_type (get_next_frame (this_frame)) == NORMAL_FRAME |
| && get_frame_pc (this_frame) == 0) |
| { |
| frame_debug_got_null_frame (gdb_stdlog, this_frame, "zero PC"); |
| return NULL; |
| } |
| |
| return get_prev_frame_1 (this_frame); |
| } |
| |
| CORE_ADDR |
| get_frame_pc (struct frame_info *frame) |
| { |
| gdb_assert (frame->next != NULL); |
| return frame_pc_unwind (frame->next); |
| } |
| |
| /* Return an address that falls within THIS_FRAME's code block. */ |
| |
| CORE_ADDR |
| get_frame_address_in_block (struct frame_info *this_frame) |
| { |
| /* A draft address. */ |
| CORE_ADDR pc = get_frame_pc (this_frame); |
| |
| struct frame_info *next_frame = this_frame->next; |
| |
| /* Calling get_frame_pc returns the resume address for THIS_FRAME. |
| Normally the resume address is inside the body of the function |
| associated with THIS_FRAME, but there is a special case: when |
| calling a function which the compiler knows will never return |
| (for instance abort), the call may be the very last instruction |
| in the calling function. The resume address will point after the |
| call and may be at the beginning of a different function |
| entirely. |
| |
| If THIS_FRAME is a signal frame or dummy frame, then we should |
| not adjust the unwound PC. For a dummy frame, GDB pushed the |
| resume address manually onto the stack. For a signal frame, the |
| OS may have pushed the resume address manually and invoked the |
| handler (e.g. GNU/Linux), or invoked the trampoline which called |
| the signal handler - but in either case the signal handler is |
| expected to return to the trampoline. So in both of these |
| cases we know that the resume address is executable and |
| related. So we only need to adjust the PC if THIS_FRAME |
| is a normal function. |
| |
| If the program has been interrupted while THIS_FRAME is current, |
| then clearly the resume address is inside the associated |
| function. There are three kinds of interruption: debugger stop |
| (next frame will be SENTINEL_FRAME), operating system |
| signal or exception (next frame will be SIGTRAMP_FRAME), |
| or debugger-induced function call (next frame will be |
| DUMMY_FRAME). So we only need to adjust the PC if |
| NEXT_FRAME is a normal function. |
| |
| We check the type of NEXT_FRAME first, since it is already |
| known; frame type is determined by the unwinder, and since |
| we have THIS_FRAME we've already selected an unwinder for |
| NEXT_FRAME. */ |
| if (get_frame_type (next_frame) == NORMAL_FRAME |
| && get_frame_type (this_frame) == NORMAL_FRAME) |
| return pc - 1; |
| |
| return 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 (get_frame_pc (frame), 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 get_frame_id (fi).stack_addr; |
| } |
| |
| /* High-level offsets into the frame. Used by the debug info. */ |
| |
| CORE_ADDR |
| get_frame_base_address (struct frame_info *fi) |
| { |
| if (get_frame_type (fi) != NORMAL_FRAME) |
| return 0; |
| if (fi->base == NULL) |
| fi->base = frame_base_find_by_frame (fi); |
| /* Sneaky: If the low-level unwind and high-level base code share a |
| common unwinder, let them share the prologue cache. */ |
| if (fi->base->unwind == fi->unwind) |
| return fi->base->this_base (fi, &fi->prologue_cache); |
| return fi->base->this_base (fi, &fi->base_cache); |
| } |
| |
| CORE_ADDR |
| get_frame_locals_address (struct frame_info *fi) |
| { |
| void **cache; |
| if (get_frame_type (fi) != NORMAL_FRAME) |
| return 0; |
| /* If there isn't a frame address method, find it. */ |
| if (fi->base == NULL) |
| fi->base = frame_base_find_by_frame (fi); |
| /* Sneaky: If the low-level unwind and high-level base code share a |
| common unwinder, let them share the prologue cache. */ |
| if (fi->base->unwind == fi->unwind) |
| return fi->base->this_locals (fi, &fi->prologue_cache); |
| return fi->base->this_locals (fi, &fi->base_cache); |
| } |
| |
| CORE_ADDR |
| get_frame_args_address (struct frame_info *fi) |
| { |
| void **cache; |
| if (get_frame_type (fi) != NORMAL_FRAME) |
| return 0; |
| /* If there isn't a frame address method, find it. */ |
| if (fi->base == NULL) |
| fi->base = frame_base_find_by_frame (fi); |
| /* Sneaky: If the low-level unwind and high-level base code share a |
| common unwinder, let them share the prologue cache. */ |
| if (fi->base->unwind == fi->unwind) |
| return fi->base->this_args (fi, &fi->prologue_cache); |
| return fi->base->this_args (fi, &fi->base_cache); |
| } |
| |
| /* 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) |
| { |
| if (frame->unwind == NULL) |
| /* Initialize the frame's unwinder because that's what |
| provides the frame's type. */ |
| frame->unwind = frame_unwind_find_by_frame (frame, &frame->prologue_cache); |
| return frame->unwind->type; |
| } |
| |
| void |
| deprecated_update_frame_pc_hack (struct frame_info *frame, CORE_ADDR pc) |
| { |
| if (frame_debug) |
| fprintf_unfiltered (gdb_stdlog, |
| "{ deprecated_update_frame_pc_hack (frame=%d,pc=0x%s) }\n", |
| frame->level, paddr_nz (pc)); |
| /* NOTE: cagney/2003-03-11: Some architectures (e.g., Arm) are |
| maintaining a locally allocated frame object. Since such frames |
| 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->prev_pc.value = pc; |
| frame->next->prev_pc.p = 1; |
| } |
| } |
| |
| void |
| deprecated_update_frame_base_hack (struct frame_info *frame, CORE_ADDR base) |
| { |
| if (frame_debug) |
| fprintf_unfiltered (gdb_stdlog, |
| "{ deprecated_update_frame_base_hack (frame=%d,base=0x%s) }\n", |
| frame->level, paddr_nz (base)); |
| /* See comment in "frame.h". */ |
| frame->this_id.value.stack_addr = base; |
| } |
| |
| /* Memory access methods. */ |
| |
| void |
| get_frame_memory (struct frame_info *this_frame, CORE_ADDR addr, |
| gdb_byte *buf, int len) |
| { |
| read_memory (addr, buf, len); |
| } |
| |
| LONGEST |
| get_frame_memory_signed (struct frame_info *this_frame, CORE_ADDR addr, |
| int len) |
| { |
| return read_memory_integer (addr, len); |
| } |
| |
| ULONGEST |
| get_frame_memory_unsigned (struct frame_info *this_frame, CORE_ADDR addr, |
| int len) |
| { |
| return read_memory_unsigned_integer (addr, len); |
| } |
| |
| int |
| safe_frame_unwind_memory (struct frame_info *this_frame, |
| CORE_ADDR addr, gdb_byte *buf, int len) |
| { |
| /* NOTE: target_read_memory returns zero on success! */ |
| return !target_read_memory (addr, buf, len); |
| } |
| |
| /* Architecture method. */ |
| |
| struct gdbarch * |
| get_frame_arch (struct frame_info *this_frame) |
| { |
| return current_gdbarch; |
| } |
| |
| /* Stack pointer methods. */ |
| |
| CORE_ADDR |
| get_frame_sp (struct frame_info *this_frame) |
| { |
| struct gdbarch *gdbarch = get_frame_arch (this_frame); |
| /* Normality - an architecture that provides a way of obtaining any |
| frame inner-most address. */ |
| if (gdbarch_unwind_sp_p (gdbarch)) |
| /* NOTE drow/2008-06-28: gdbarch_unwind_sp could be converted to |
| operate on THIS_FRAME now. */ |
| return gdbarch_unwind_sp (gdbarch, this_frame->next); |
| /* Now things are really are grim. Hope that the value returned by |
| the gdbarch_sp_regnum register is meaningful. */ |
| if (gdbarch_sp_regnum (gdbarch) >= 0) |
| return get_frame_register_unsigned (this_frame, |
| gdbarch_sp_regnum (gdbarch)); |
| internal_error (__FILE__, __LINE__, _("Missing unwind SP method")); |
| } |
| |
| /* Return the reason why we can't unwind past FRAME. */ |
| |
| enum unwind_stop_reason |
| get_frame_unwind_stop_reason (struct frame_info *frame) |
| { |
| /* If we haven't tried to unwind past this point yet, then assume |
| that unwinding would succeed. */ |
| if (frame->prev_p == 0) |
| return UNWIND_NO_REASON; |
| |
| /* Otherwise, we set a reason when we succeeded (or failed) to |
| unwind. */ |
| return frame->stop_reason; |
| } |
| |
| /* Return a string explaining REASON. */ |
| |
| const char * |
| frame_stop_reason_string (enum unwind_stop_reason reason) |
| { |
| switch (reason) |
| { |
| case UNWIND_NULL_ID: |
| return _("unwinder did not report frame ID"); |
| |
| case UNWIND_INNER_ID: |
| return _("previous frame inner to this frame (corrupt stack?)"); |
| |
| case UNWIND_SAME_ID: |
| return _("previous frame identical to this frame (corrupt stack?)"); |
| |
| case UNWIND_NO_SAVED_PC: |
| return _("frame did not save the PC"); |
| |
| case UNWIND_NO_REASON: |
| case UNWIND_FIRST_ERROR: |
| default: |
| internal_error (__FILE__, __LINE__, |
| "Invalid frame stop reason"); |
| } |
| } |
| |
| /* Clean up after a failed (wrong unwinder) attempt to unwind past |
| FRAME. */ |
| |
| static void |
| frame_cleanup_after_sniffer (void *arg) |
| { |
| struct frame_info *frame = arg; |
| |
| /* The sniffer should not allocate a prologue cache if it did not |
| match this frame. */ |
| gdb_assert (frame->prologue_cache == NULL); |
| |
| /* No sniffer should extend the frame chain; sniff based on what is |
| already certain. */ |
| gdb_assert (!frame->prev_p); |
| |
| /* The sniffer should not check the frame's ID; that's circular. */ |
| gdb_assert (!frame->this_id.p); |
| |
| /* Clear cached fields dependent on the unwinder. |
| |
| The previous PC is independent of the unwinder, but the previous |
| function is not (see get_frame_address_in_block). */ |
| frame->prev_func.p = 0; |
| frame->prev_func.addr = 0; |
| |
| /* Discard the unwinder last, so that we can easily find it if an assertion |
| in this function triggers. */ |
| frame->unwind = NULL; |
| } |
| |
| /* Set FRAME's unwinder temporarily, so that we can call a sniffer. |
| Return a cleanup which should be called if unwinding fails, and |
| discarded if it succeeds. */ |
| |
| struct cleanup * |
| frame_prepare_for_sniffer (struct frame_info *frame, |
| const struct frame_unwind *unwind) |
| { |
| gdb_assert (frame->unwind == NULL); |
| frame->unwind = unwind; |
| return make_cleanup (frame_cleanup_after_sniffer, frame); |
| } |
| |
| extern initialize_file_ftype _initialize_frame; /* -Wmissing-prototypes */ |
| |
| static struct cmd_list_element *set_backtrace_cmdlist; |
| static struct cmd_list_element *show_backtrace_cmdlist; |
| |
| static void |
| set_backtrace_cmd (char *args, int from_tty) |
| { |
| help_list (set_backtrace_cmdlist, "set backtrace ", -1, gdb_stdout); |
| } |
| |
| static void |
| show_backtrace_cmd (char *args, int from_tty) |
| { |
| cmd_show_list (show_backtrace_cmdlist, from_tty, ""); |
| } |
| |
| void |
| _initialize_frame (void) |
| { |
| obstack_init (&frame_cache_obstack); |
| |
| observer_attach_target_changed (frame_observer_target_changed); |
| |
| add_prefix_cmd ("backtrace", class_maintenance, set_backtrace_cmd, _("\ |
| Set backtrace specific variables.\n\ |
| Configure backtrace variables such as the backtrace limit"), |
| &set_backtrace_cmdlist, "set backtrace ", |
| 0/*allow-unknown*/, &setlist); |
| add_prefix_cmd ("backtrace", class_maintenance, show_backtrace_cmd, _("\ |
| Show backtrace specific variables\n\ |
| Show backtrace variables such as the backtrace limit"), |
| &show_backtrace_cmdlist, "show backtrace ", |
| 0/*allow-unknown*/, &showlist); |
| |
| add_setshow_boolean_cmd ("past-main", class_obscure, |
| &backtrace_past_main, _("\ |
| Set whether backtraces should continue past \"main\"."), _("\ |
| Show whether backtraces should continue past \"main\"."), _("\ |
| 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, |
| show_backtrace_past_main, |
| &set_backtrace_cmdlist, |
| &show_backtrace_cmdlist); |
| |
| add_setshow_boolean_cmd ("past-entry", class_obscure, |
| &backtrace_past_entry, _("\ |
| Set whether backtraces should continue past the entry point of a program."), |
| _("\ |
| Show whether backtraces should continue past the entry point of a program."), |
| _("\ |
| Normally there are no callers beyond the entry point of a program, so GDB\n\ |
| will terminate the backtrace there. Set this variable if you need to see \n\ |
| the rest of the stack trace."), |
| NULL, |
| show_backtrace_past_entry, |
| &set_backtrace_cmdlist, |
| &show_backtrace_cmdlist); |
| |
| add_setshow_integer_cmd ("limit", class_obscure, |
| &backtrace_limit, _("\ |
| Set an upper bound on the number of backtrace levels."), _("\ |
| Show the upper bound on the number of backtrace levels."), _("\ |
| No more than the specified number of frames can be displayed or examined.\n\ |
| Zero is unlimited."), |
| NULL, |
| show_backtrace_limit, |
| &set_backtrace_cmdlist, |
| &show_backtrace_cmdlist); |
| |
| /* Debug this files internals. */ |
| add_setshow_zinteger_cmd ("frame", class_maintenance, &frame_debug, _("\ |
| Set frame debugging."), _("\ |
| Show frame debugging."), _("\ |
| When non-zero, frame specific internal debugging is enabled."), |
| NULL, |
| show_frame_debug, |
| &setdebuglist, &showdebuglist); |
| } |