diff options
Diffstat (limited to 'gdb/frame.c')
| -rw-r--r-- | gdb/frame.c | 786 |
1 files changed, 504 insertions, 282 deletions
diff --git a/gdb/frame.c b/gdb/frame.c index ecdf408c5cf..0c3009cf4d5 100644 --- a/gdb/frame.c +++ b/gdb/frame.c @@ -1,7 +1,7 @@ /* Cache and manage frames for GDB, the GNU debugger. Copyright 1986, 1987, 1989, 1991, 1994, 1995, 1996, 1998, 2000, - 2001, 2002 Free Software Foundation, Inc. + 2001, 2002, 2003 Free Software Foundation, Inc. This file is part of GDB. @@ -31,9 +31,17 @@ #include "builtin-regs.h" #include "gdb_obstack.h" #include "dummy-frame.h" +#include "sentinel-frame.h" #include "gdbcore.h" #include "annotate.h" #include "language.h" +#include "frame-unwind.h" +#include "command.h" +#include "gdbcmd.h" + +/* Flag to indicate whether backtraces should stop at main. */ + +static int backtrace_below_main; /* Return a frame uniq ID that can be used to, later, re-find the frame. */ @@ -127,7 +135,7 @@ frame_pc_unwind (struct frame_info *frame) { if (!frame->pc_unwind_cache_p) { - frame->pc_unwind_cache = frame->pc_unwind (frame, &frame->unwind_cache); + frame->pc_unwind_cache = frame->unwind->pc (frame, &frame->unwind_cache); frame->pc_unwind_cache_p = 1; } return frame->pc_unwind_cache; @@ -138,13 +146,24 @@ frame_id_unwind (struct frame_info *frame) { if (!frame->id_unwind_cache_p) { - frame->id_unwind_cache = - frame->id_unwind (frame, &frame->unwind_cache); + frame->unwind->id (frame, &frame->unwind_cache, &frame->id_unwind_cache); frame->id_unwind_cache_p = 1; } return frame->id_unwind_cache; } +void +frame_pop (struct frame_info *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); + flush_cached_frames (); +} void frame_register_unwind (struct frame_info *frame, int regnum, @@ -161,33 +180,15 @@ frame_register_unwind (struct frame_info *frame, int regnum, gdb_assert (realnump != NULL); /* gdb_assert (bufferp != NULL); */ - /* NOTE: cagney/2002-04-14: It would be nice if, instead of a - special case, there was always an inner frame dedicated to the - hardware registers. Unfortunatly, there is too much unwind code - around that looks up/down the frame chain while making the - assumption that each frame level is using the same unwind code. */ - - if (frame == NULL) - { - /* We're in the inner-most frame, get the value direct from the - register cache. */ - *optimizedp = 0; - *lvalp = lval_register; - /* ULGH! Code uses the offset into the raw register byte array - as a way of identifying a register. */ - *addrp = REGISTER_BYTE (regnum); - /* Should this code test ``register_cached (regnum) < 0'' and do - something like set realnum to -1 when the register isn't - available? */ - *realnump = regnum; - if (bufferp) - deprecated_read_register_gen (regnum, bufferp); - return; - } + /* NOTE: cagney/2002-11-27: A program trying to unwind a NULL frame + is broken. There is always a frame. If there, for some reason, + isn't, there is some pretty busted code as it should have + detected the problem before calling here. */ + gdb_assert (frame != NULL); /* Ask this frame to unwind its register. */ - frame->register_unwind (frame, &frame->unwind_cache, regnum, - optimizedp, lvalp, addrp, realnump, bufferp); + frame->unwind->reg (frame, &frame->unwind_cache, regnum, + optimizedp, lvalp, addrp, realnump, bufferp); } void @@ -229,38 +230,30 @@ frame_register (struct frame_info *frame, int regnum, return; } - /* Reached the the bottom (youngest, inner most) of the frame chain - (youngest, inner most) frame, go direct to the hardware register - cache (do not pass go, do not try to cache the value, ...). The - unwound value would have been cached in frame->next but that - doesn't exist. This doesn't matter as the hardware register - cache is stopping any unnecessary accesses to the target. */ - - /* NOTE: cagney/2002-04-14: It would be nice if, instead of a - special case, there was always an inner frame dedicated to the - hardware registers. Unfortunatly, there is too much unwind code - around that looks up/down the frame chain while making the - assumption that each frame level is using the same unwind code. */ - - if (frame == NULL) - frame_register_unwind (NULL, regnum, optimizedp, lvalp, addrp, realnump, - bufferp); - else - frame_register_unwind (frame->next, regnum, optimizedp, lvalp, addrp, - realnump, bufferp); + /* Obtain the register value by unwinding the register from the next + (more inner frame). */ + gdb_assert (frame != NULL && frame->next != NULL); + frame_register_unwind (frame->next, regnum, optimizedp, lvalp, addrp, + realnump, bufferp); } void -frame_unwind_signed_register (struct frame_info *frame, int regnum, - LONGEST *val) +frame_unwind_register (struct frame_info *frame, int regnum, void *buf) { int optimized; CORE_ADDR addr; int realnum; enum lval_type lval; - void *buf = alloca (MAX_REGISTER_RAW_SIZE); frame_register_unwind (frame, regnum, &optimized, &lval, &addr, &realnum, buf); +} + +void +frame_unwind_signed_register (struct frame_info *frame, int regnum, + LONGEST *val) +{ + void *buf = alloca (MAX_REGISTER_RAW_SIZE); + frame_unwind_register (frame, regnum, buf); (*val) = extract_signed_integer (buf, REGISTER_VIRTUAL_SIZE (regnum)); } @@ -268,17 +261,19 @@ void frame_unwind_unsigned_register (struct frame_info *frame, int regnum, ULONGEST *val) { - int optimized; - CORE_ADDR addr; - int realnum; - enum lval_type lval; void *buf = alloca (MAX_REGISTER_RAW_SIZE); - frame_register_unwind (frame, regnum, &optimized, &lval, &addr, - &realnum, buf); + frame_unwind_register (frame, regnum, buf); (*val) = extract_unsigned_integer (buf, REGISTER_VIRTUAL_SIZE (regnum)); } void +frame_read_register (struct frame_info *frame, int regnum, void *buf) +{ + gdb_assert (frame != NULL && frame->next != NULL); + frame_unwind_register (frame->next, regnum, buf); +} + +void frame_read_unsigned_register (struct frame_info *frame, int regnum, ULONGEST *val) { @@ -299,17 +294,17 @@ frame_read_unsigned_register (struct frame_info *frame, int regnum, tests like ``if get_next_frame() == NULL'' and instead just rely on recursive frame calls (like the below code) when manipulating a frame chain. */ - gdb_assert (frame != NULL); - frame_unwind_unsigned_register (get_next_frame (frame), regnum, val); + gdb_assert (frame != NULL && frame->next != NULL); + frame_unwind_unsigned_register (frame->next, regnum, val); } void frame_read_signed_register (struct frame_info *frame, int regnum, LONGEST *val) { - /* See note in frame_read_unsigned_register(). */ - gdb_assert (frame != NULL); - frame_unwind_signed_register (get_next_frame (frame), regnum, val); + /* See note above in frame_read_unsigned_register(). */ + gdb_assert (frame != NULL && frame->next != NULL); + frame_unwind_signed_register (frame->next, regnum, val); } static void @@ -337,25 +332,9 @@ generic_unwind_get_saved_register (char *raw_buffer, if (addrp == NULL) addrp = &addrx; - /* Reached the the bottom (youngest, inner most) of the frame chain - (youngest, inner most) frame, go direct to the hardware register - cache (do not pass go, do not try to cache the value, ...). The - unwound value would have been cached in frame->next but that - doesn't exist. This doesn't matter as the hardware register - cache is stopping any unnecessary accesses to the target. */ - - /* NOTE: cagney/2002-04-14: It would be nice if, instead of a - special case, there was always an inner frame dedicated to the - hardware registers. Unfortunatly, there is too much unwind code - around that looks up/down the frame chain while making the - assumption that each frame level is using the same unwind code. */ - - if (frame == NULL) - frame_register_unwind (NULL, regnum, optimizedp, lvalp, addrp, &realnumx, - raw_buffer); - else - frame_register_unwind (frame->next, regnum, optimizedp, lvalp, addrp, - &realnumx, raw_buffer); + gdb_assert (frame != NULL && frame->next != NULL); + frame_register_unwind (frame->next, regnum, optimizedp, lvalp, addrp, + &realnumx, raw_buffer); } void @@ -414,6 +393,9 @@ frame_map_name_to_regnum (const char *name, int len) { int i; + if (len < 0) + len = strlen (name); + /* Search register name space. */ for (i = 0; i < NUM_REGS + NUM_PSEUDO_REGS; i++) if (REGISTER_NAME (i) && len == strlen (REGISTER_NAME (i)) @@ -445,6 +427,32 @@ frame_map_regnum_to_name (int regnum) return builtin_reg_map_regnum_to_name (regnum); } +/* Create a sentinel frame. */ + +struct frame_info * +create_sentinel_frame (struct regcache *regcache) +{ + struct frame_info *frame = FRAME_OBSTACK_ZALLOC (struct frame_info); + frame->type = NORMAL_FRAME; + frame->level = -1; + /* Explicitly initialize the sentinel frame's cache. Provide it + with the underlying regcache. In the future additional + information, such as the frame's thread will be added. */ + frame->unwind_cache = sentinel_frame_cache (regcache); + /* For the moment there is only one sentinel frame implementation. */ + frame->unwind = sentinel_frame_unwind; + /* Link this frame back to itself. The frame is self referential + (the unwound PC is the same as the pc), so make it so. */ + frame->next = frame; + /* Always unwind the PC as part of creating this frame. This + ensures that the frame's PC points at something valid. */ + /* FIXME: cagney/2003-01-10: Problem here. Unwinding a sentinel + frame's PC may require information such as the frame's thread's + stop reason. Is it possible to get to that? */ + frame->pc = frame_pc_unwind (frame); + return frame; +} + /* Info about the innermost stack frame (contents of FP register) */ static struct frame_info *current_frame; @@ -456,17 +464,18 @@ static struct frame_info *current_frame; static struct obstack frame_cache_obstack; void * -frame_obstack_alloc (unsigned long size) +frame_obstack_zalloc (unsigned long size) { - return obstack_alloc (&frame_cache_obstack, size); + void *data = obstack_alloc (&frame_cache_obstack, size); + memset (data, 0, size); + return data; } CORE_ADDR * frame_saved_regs_zalloc (struct frame_info *fi) { fi->saved_regs = (CORE_ADDR *) - frame_obstack_alloc (SIZEOF_FRAME_SAVED_REGS); - memset (fi->saved_regs, 0, SIZEOF_FRAME_SAVED_REGS); + frame_obstack_zalloc (SIZEOF_FRAME_SAVED_REGS); return fi->saved_regs; } @@ -476,17 +485,43 @@ get_frame_saved_regs (struct frame_info *fi) return fi->saved_regs; } -/* Return the innermost (currently executing) stack frame. */ +/* Return the innermost (currently executing) stack frame. This is + split into two functions. The function unwind_to_current_frame() + is wrapped in catch exceptions so that, even when the unwind of the + sentinel frame fails, the function still returns a stack frame. */ + +static int +unwind_to_current_frame (struct ui_out *ui_out, void *args) +{ + struct frame_info *frame = get_prev_frame (args); + /* A sentinel frame can fail to unwind, eg, because it's PC value + lands in somewhere like start. */ + if (frame == NULL) + return 1; + current_frame = frame; + return 0; +} struct frame_info * get_current_frame (void) { + if (!target_has_stack) + error ("No stack."); + if (!target_has_registers) + error ("No registers."); + if (!target_has_memory) + error ("No memory."); if (current_frame == NULL) { - if (target_has_stack) - current_frame = create_new_frame (read_fp (), read_pc ()); - else - error ("No stack."); + struct frame_info *sentinel_frame = + create_sentinel_frame (current_regcache); + if (catch_exceptions (uiout, unwind_to_current_frame, sentinel_frame, + NULL, RETURN_MASK_ERROR) != 0) + { + /* Oops! Fake a current frame? Is this useful? It has a PC + of zero, for instance. */ + current_frame = sentinel_frame; + } } return current_frame; } @@ -569,12 +604,16 @@ frame_saved_regs_register_unwind (struct frame_info *frame, void **cache, gdb_assert (!(DEPRECATED_USE_GENERIC_DUMMY_FRAMES && (get_frame_type (frame) == DUMMY_FRAME))); + /* Only (older) architectures that implement the + FRAME_INIT_SAVED_REGS method should be using this function. */ + gdb_assert (FRAME_INIT_SAVED_REGS_P ()); + /* Load the saved_regs register cache. */ - if (frame->saved_regs == NULL) + if (get_frame_saved_regs (frame) == NULL) FRAME_INIT_SAVED_REGS (frame); - if (frame->saved_regs != NULL - && frame->saved_regs[regnum] != 0) + if (get_frame_saved_regs (frame) != NULL + && get_frame_saved_regs (frame)[regnum] != 0) { if (regnum == SP_REGNUM) { @@ -585,7 +624,7 @@ frame_saved_regs_register_unwind (struct frame_info *frame, void **cache, *realnump = -1; if (bufferp != NULL) store_address (bufferp, REGISTER_RAW_SIZE (regnum), - frame->saved_regs[regnum]); + get_frame_saved_regs (frame)[regnum]); } else { @@ -593,7 +632,7 @@ frame_saved_regs_register_unwind (struct frame_info *frame, void **cache, a local copy of its value. */ *optimizedp = 0; *lvalp = lval_memory; - *addrp = frame->saved_regs[regnum]; + *addrp = get_frame_saved_regs (frame)[regnum]; *realnump = -1; if (bufferp != NULL) { @@ -605,21 +644,20 @@ frame_saved_regs_register_unwind (struct frame_info *frame, void **cache, { int sizeof_cache = ((NUM_REGS + NUM_PSEUDO_REGS) * sizeof (void *)); - regs = frame_obstack_alloc (sizeof_cache); - memset (regs, 0, sizeof_cache); + regs = frame_obstack_zalloc (sizeof_cache); (*cache) = regs; } if (regs[regnum] == NULL) { regs[regnum] - = frame_obstack_alloc (REGISTER_RAW_SIZE (regnum)); - read_memory (frame->saved_regs[regnum], regs[regnum], + = frame_obstack_zalloc (REGISTER_RAW_SIZE (regnum)); + read_memory (get_frame_saved_regs (frame)[regnum], regs[regnum], REGISTER_RAW_SIZE (regnum)); } memcpy (bufferp, regs[regnum], REGISTER_RAW_SIZE (regnum)); #else /* Read the value in from memory. */ - read_memory (frame->saved_regs[regnum], bufferp, + read_memory (get_frame_saved_regs (frame)[regnum], bufferp, REGISTER_RAW_SIZE (regnum)); #endif } @@ -628,36 +666,32 @@ frame_saved_regs_register_unwind (struct frame_info *frame, void **cache, } /* No luck, assume this and the next frame have the same register - value. If a value is needed, pass the request on down the chain; - otherwise just return an indication that the value is in the same - register as the next frame. */ - if (bufferp == NULL) - { - *optimizedp = 0; - *lvalp = lval_register; - *addrp = 0; - *realnump = regnum; - } - else - { - frame_register_unwind (frame->next, regnum, optimizedp, lvalp, addrp, - realnump, bufferp); - } + value. Pass the request down the frame chain to the next frame. + Hopefully that will find the register's location, either in a + register or in memory. */ + frame_register (frame, regnum, optimizedp, lvalp, addrp, realnump, + bufferp); } static CORE_ADDR frame_saved_regs_pc_unwind (struct frame_info *frame, void **cache) { + gdb_assert (FRAME_SAVED_PC_P ()); return FRAME_SAVED_PC (frame); } -static struct frame_id -frame_saved_regs_id_unwind (struct frame_info *next_frame, void **cache) +static void +frame_saved_regs_id_unwind (struct frame_info *next_frame, void **cache, + struct frame_id *id) { int fromleaf; - struct frame_id id; + CORE_ADDR base; + CORE_ADDR pc; + + /* Start out by assuming it's NULL. */ + (*id) = null_frame_id; - if (next_frame->next == NULL) + if (frame_relative_level (next_frame) <= 0) /* FIXME: 2002-11-09: Frameless functions can occure anywhere in the frame chain, not just the inner most frame! The generic, per-architecture, frame code should handle this and the below @@ -673,7 +707,7 @@ frame_saved_regs_id_unwind (struct frame_info *next_frame, void **cache) /* FIXME: 2002-11-09: There isn't any reason to special case this edge condition. Instead the per-architecture code should hande it locally. */ - id.base = get_frame_base (next_frame); + base = get_frame_base (next_frame); else { /* Two macros defined in tm.h specify the machine-dependent @@ -691,28 +725,39 @@ frame_saved_regs_id_unwind (struct frame_info *next_frame, void **cache) this to after the ffi test; I'd rather have backtraces from start go curfluy than have an abort called from main not show main. */ - id.base = FRAME_CHAIN (next_frame); - - /* FIXME: cagney/2002-06-08: There should be two tests here. - The first would check for a valid frame chain based on a user - selectable policy. The default being ``stop at main'' (as - implemented by generic_func_frame_chain_valid()). Other - policies would be available - stop at NULL, .... The second - test, if provided by the target architecture, would check for - more exotic cases - most target architectures wouldn't bother - with this second case. */ - if (!FRAME_CHAIN_VALID (id.base, next_frame)) - return null_frame_id; + gdb_assert (FRAME_CHAIN_P ()); + base = FRAME_CHAIN (next_frame); + + if (!frame_chain_valid (base, next_frame)) + return; } - if (id.base == 0) - return null_frame_id; + if (base == 0) + return; /* FIXME: cagney/2002-06-08: This should probably return the frame's function and not the PC (a.k.a. resume address). */ - id.pc = frame_pc_unwind (next_frame); - return id; + pc = frame_pc_unwind (next_frame); + id->pc = pc; + 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 +}; +const struct frame_unwind *trad_frame_unwind = &trad_frame_unwinder; + + /* Function: get_saved_register Find register number REGNUM relative to FRAME and put its (raw, target format) contents in *RAW_BUFFER. @@ -746,6 +791,8 @@ deprecated_generic_get_saved_register (char *raw_buffer, int *optimized, if (!target_has_registers) error ("No registers."); + gdb_assert (FRAME_INIT_SAVED_REGS_P ()); + /* Normal systems don't optimize out things with register numbers. */ if (optimized != NULL) *optimized = 0; @@ -758,44 +805,50 @@ deprecated_generic_get_saved_register (char *raw_buffer, int *optimized, the current frame itself: otherwise, we would be getting the previous frame's registers which were saved by the current frame. */ - while (frame && ((frame = frame->next) != NULL)) + if (frame != NULL) { - if (get_frame_type (frame) == DUMMY_FRAME) - { - if (lval) /* found it in a CALL_DUMMY frame */ - *lval = not_lval; - if (raw_buffer) - /* FIXME: cagney/2002-06-26: This should be via the - gdbarch_register_read() method so that it, on the fly, - constructs either a raw or pseudo register from the raw - register cache. */ - regcache_raw_read (generic_find_dummy_frame (frame->pc, - frame->frame), - regnum, raw_buffer); - return; - } - - FRAME_INIT_SAVED_REGS (frame); - if (frame->saved_regs != NULL - && frame->saved_regs[regnum] != 0) + for (frame = get_next_frame (frame); + frame_relative_level (frame) >= 0; + frame = get_next_frame (frame)) { - if (lval) /* found it saved on the stack */ - *lval = lval_memory; - if (regnum == SP_REGNUM) + if (get_frame_type (frame) == DUMMY_FRAME) { - if (raw_buffer) /* SP register treated specially */ - store_address (raw_buffer, REGISTER_RAW_SIZE (regnum), - frame->saved_regs[regnum]); + if (lval) /* found it in a CALL_DUMMY frame */ + *lval = not_lval; + if (raw_buffer) + /* FIXME: cagney/2002-06-26: This should be via the + gdbarch_register_read() method so that it, on the + fly, constructs either a raw or pseudo register + from the raw register cache. */ + regcache_raw_read + (generic_find_dummy_frame (get_frame_pc (frame), + get_frame_base (frame)), + regnum, raw_buffer); + return; } - else + + FRAME_INIT_SAVED_REGS (frame); + if (get_frame_saved_regs (frame) != NULL + && get_frame_saved_regs (frame)[regnum] != 0) { - if (addrp) /* any other register */ - *addrp = frame->saved_regs[regnum]; - if (raw_buffer) - read_memory (frame->saved_regs[regnum], raw_buffer, - REGISTER_RAW_SIZE (regnum)); + if (lval) /* found it saved on the stack */ + *lval = lval_memory; + if (regnum == SP_REGNUM) + { + if (raw_buffer) /* SP register treated specially */ + store_address (raw_buffer, REGISTER_RAW_SIZE (regnum), + get_frame_saved_regs (frame)[regnum]); + } + else + { + if (addrp) /* any other register */ + *addrp = get_frame_saved_regs (frame)[regnum]; + if (raw_buffer) + read_memory (get_frame_saved_regs (frame)[regnum], raw_buffer, + REGISTER_RAW_SIZE (regnum)); + } + return; } - return; } } @@ -810,39 +863,26 @@ deprecated_generic_get_saved_register (char *raw_buffer, int *optimized, deprecated_read_register_gen (regnum, raw_buffer); } -/* Using the PC, select a mechanism for unwinding a frame returning - the previous frame. The register unwind function should, on - demand, initialize the ->context object. */ +/* Determine the frame's type based on its PC. */ -static void -set_unwind_by_pc (CORE_ADDR pc, CORE_ADDR fp, - frame_register_unwind_ftype **unwind_register, - frame_pc_unwind_ftype **unwind_pc, - frame_id_unwind_ftype **unwind_id) +static enum frame_type +frame_type_from_pc (CORE_ADDR pc) { - if (!DEPRECATED_USE_GENERIC_DUMMY_FRAMES) - { - /* Still need to set this to something. The ``info frame'' code - calls this function to find out where the saved registers are. - Hopefully this is robust enough to stop any core dumps and - return vaguely correct values.. */ - *unwind_register = frame_saved_regs_register_unwind; - *unwind_pc = frame_saved_regs_pc_unwind; - *unwind_id = frame_saved_regs_id_unwind; - } - else if (DEPRECATED_PC_IN_CALL_DUMMY_P () - ? DEPRECATED_PC_IN_CALL_DUMMY (pc, 0, 0) - : pc_in_dummy_frame (pc)) - { - *unwind_register = dummy_frame_register_unwind; - *unwind_pc = dummy_frame_pc_unwind; - *unwind_id = dummy_frame_id_unwind; - } + /* FIXME: cagney/2002-11-24: Can't yet directly call + pc_in_dummy_frame() as some architectures don't set + PC_IN_CALL_DUMMY() to generic_pc_in_call_dummy() (remember the + latter is implemented by simply calling pc_in_dummy_frame). */ + if (DEPRECATED_USE_GENERIC_DUMMY_FRAMES + && DEPRECATED_PC_IN_CALL_DUMMY (pc, 0, 0)) + return DUMMY_FRAME; else { - *unwind_register = frame_saved_regs_register_unwind; - *unwind_pc = frame_saved_regs_pc_unwind; - *unwind_id = frame_saved_regs_id_unwind; + char *name; + find_pc_partial_function (pc, &name, NULL, NULL); + if (PC_IN_SIGTRAMP (pc, name)) + return SIGTRAMP_FRAME; + else + return NORMAL_FRAME; } } @@ -853,59 +893,34 @@ struct frame_info * create_new_frame (CORE_ADDR addr, CORE_ADDR pc) { struct frame_info *fi; - enum frame_type type; - - fi = (struct frame_info *) - obstack_alloc (&frame_cache_obstack, - sizeof (struct frame_info)); - /* Zero all fields by default. */ - memset (fi, 0, sizeof (struct frame_info)); + fi = frame_obstack_zalloc (sizeof (struct frame_info)); fi->frame = addr; fi->pc = pc; - /* NOTE: cagney/2002-11-18: The code segments, found in - create_new_frame and get_prev_frame(), that initializes the - frames type is subtly different. The latter only updates ->type - when it encounters a SIGTRAMP_FRAME or DUMMY_FRAME. This stops - get_prev_frame() overriding the frame's type when the INIT code - has previously set it. This is really somewhat bogus. The - initialization, as seen in create_new_frame(), should occur - before the INIT function has been called. */ - if (DEPRECATED_USE_GENERIC_DUMMY_FRAMES - && (DEPRECATED_PC_IN_CALL_DUMMY_P () - ? DEPRECATED_PC_IN_CALL_DUMMY (pc, 0, 0) - : pc_in_dummy_frame (pc))) - /* NOTE: cagney/2002-11-11: Does this even occure? */ - type = DUMMY_FRAME; - else - { - char *name; - find_pc_partial_function (pc, &name, NULL, NULL); - if (PC_IN_SIGTRAMP (fi->pc, name)) - type = SIGTRAMP_FRAME; - else - type = NORMAL_FRAME; - } - fi->type = type; + fi->next = create_sentinel_frame (current_regcache); + fi->type = frame_type_from_pc (pc); if (INIT_EXTRA_FRAME_INFO_P ()) INIT_EXTRA_FRAME_INFO (0, fi); /* Select/initialize an unwind function. */ - set_unwind_by_pc (fi->pc, fi->frame, &fi->register_unwind, - &fi->pc_unwind, &fi->id_unwind); + fi->unwind = frame_unwind_find_by_pc (current_gdbarch, fi->pc); return fi; } /* Return the frame that FRAME calls (NULL if FRAME is the innermost - frame). */ + frame). Be careful to not fall off the bottom of the frame chain + and onto the sentinel frame. */ struct frame_info * get_next_frame (struct frame_info *frame) { - return frame->next; + if (frame->level > 0) + return frame->next; + else + return NULL; } /* Flush the entire frame cache. */ @@ -936,43 +951,19 @@ reinit_frame_cache (void) } } -/* Return a structure containing various interesting information - about the frame that called NEXT_FRAME. Returns NULL - if there is no such frame. */ +/* Create the previous frame using the deprecated methods + INIT_EXTRA_INFO, INIT_FRAME_PC and INIT_FRAME_PC_FIRST. */ -struct frame_info * -get_prev_frame (struct frame_info *next_frame) +static struct frame_info * +legacy_get_prev_frame (struct frame_info *next_frame) { CORE_ADDR address = 0; struct frame_info *prev; int fromleaf; - /* Return the inner-most frame, when the caller passes in NULL. */ - /* NOTE: cagney/2002-11-09: Not sure how this would happen. The - caller should have previously obtained a valid frame using - get_selected_frame() and then called this code - only possibility - I can think of is code behaving badly. */ - if (next_frame == NULL) - { - /* NOTE: cagney/2002-11-09: There was a code segment here that - would error out when CURRENT_FRAME was NULL. The comment - that went with it made the claim ... - - ``This screws value_of_variable, which just wants a nice - clean NULL return from block_innermost_frame if there are no - frames. I don't think I've ever seen this message happen - otherwise. And returning NULL here is a perfectly legitimate - thing to do.'' - - Per the above, this code shouldn't even be called with a NULL - NEXT_FRAME. */ - return current_frame; - } - - /* Only try to do the unwind once. */ - if (next_frame->prev_p) - return next_frame->prev; - next_frame->prev_p = 1; + /* This code only works on normal frames. A sentinel frame, where + the level is -1, should never reach this code. */ + gdb_assert (next_frame->level >= 0); /* On some machines it is possible to call a function without setting up a stack frame for it. On these machines, we @@ -983,7 +974,7 @@ get_prev_frame (struct frame_info *next_frame) /* Still don't want to worry about this except on the innermost frame. This macro will set FROMLEAF if NEXT_FRAME is a frameless function invocation. */ - if (next_frame->next == NULL) + if (next_frame->level == 0) /* FIXME: 2002-11-09: Frameless functions can occure anywhere in the frame chain, not just the inner most frame! The generic, per-architecture, frame code should handle this and the below @@ -1017,27 +1008,17 @@ get_prev_frame (struct frame_info *next_frame) this to after the ffi test; I'd rather have backtraces from start go curfluy than have an abort called from main not show main. */ + gdb_assert (FRAME_CHAIN_P ()); address = FRAME_CHAIN (next_frame); - /* FIXME: cagney/2002-06-08: There should be two tests here. - The first would check for a valid frame chain based on a user - selectable policy. The default being ``stop at main'' (as - implemented by generic_func_frame_chain_valid()). Other - policies would be available - stop at NULL, .... The second - test, if provided by the target architecture, would check for - more exotic cases - most target architectures wouldn't bother - with this second case. */ - if (!FRAME_CHAIN_VALID (address, next_frame)) + if (!frame_chain_valid (address, next_frame)) return 0; } if (address == 0) return 0; /* Create an initially zero previous frame. */ - prev = (struct frame_info *) - obstack_alloc (&frame_cache_obstack, - sizeof (struct frame_info)); - memset (prev, 0, sizeof (struct frame_info)); + prev = frame_obstack_zalloc (sizeof (struct frame_info)); /* Link it in. */ next_frame->prev = prev; @@ -1148,8 +1129,7 @@ get_prev_frame (struct frame_info *next_frame) (and probably other architectural information). The PC lets you check things like the debug info at that point (dwarf2cfi?) and use that to decide how the frame should be unwound. */ - set_unwind_by_pc (prev->pc, prev->frame, &prev->register_unwind, - &prev->pc_unwind, &prev->id_unwind); + prev->unwind = frame_unwind_find_by_pc (current_gdbarch, prev->pc); /* NOTE: cagney/2002-11-18: The code segments, found in create_new_frame and get_prev_frame(), that initializes the @@ -1187,6 +1167,163 @@ get_prev_frame (struct frame_info *next_frame) return prev; } +/* Return a structure containing various interesting information + about the frame that called NEXT_FRAME. Returns NULL + if there is no such frame. */ + +struct frame_info * +get_prev_frame (struct frame_info *next_frame) +{ + struct frame_info *prev_frame; + + /* Return the inner-most frame, when the caller passes in NULL. */ + /* NOTE: cagney/2002-11-09: Not sure how this would happen. The + caller should have previously obtained a valid frame using + get_selected_frame() and then called this code - only possibility + I can think of is code behaving badly. + + NOTE: cagney/2003-01-10: Talk about code behaving badly. Check + block_innermost_frame(). It does the sequence: frame = NULL; + while (1) { frame = get_prev_frame (frame); .... }. Ulgh! Why + it couldn't be written better, I don't know. + + NOTE: cagney/2003-01-11: I suspect what is happening is + block_innermost_frame() is, when the target has no state + (registers, memory, ...), still calling this function. The + assumption being that this function will return NULL indicating + that a frame isn't possible, rather than checking that the target + has state and then calling get_current_frame() and + get_prev_frame(). This is a guess mind. */ + if (next_frame == NULL) + { + /* NOTE: cagney/2002-11-09: There was a code segment here that + would error out when CURRENT_FRAME was NULL. The comment + that went with it made the claim ... + + ``This screws value_of_variable, which just wants a nice + clean NULL return from block_innermost_frame if there are no + frames. I don't think I've ever seen this message happen + otherwise. And returning NULL here is a perfectly legitimate + thing to do.'' + + Per the above, this code shouldn't even be called with a NULL + NEXT_FRAME. */ + return current_frame; + } + + /* There is always a frame. If this assertion fails, suspect that + something should be calling get_selected_frame() or + get_current_frame(). */ + gdb_assert (next_frame != NULL); + + if (next_frame->level >= 0 + && !backtrace_below_main + && inside_main_func (get_frame_pc (next_frame))) + /* Don't unwind past main(), bug always unwind the sentinel frame. + Note, this is done _before_ the frame has been marked as + previously unwound. That way if the user later decides to + allow unwinds past main(), that just happens. */ + return NULL; + + /* Only try to do the unwind once. */ + if (next_frame->prev_p) + return next_frame->prev; + next_frame->prev_p = 1; + + /* If we're inside the entry file, it isn't valid. */ + /* NOTE: drow/2002-12-25: should there be a way to disable this + check? It assumes a single small entry file, and the way some + debug readers (e.g. dbxread) figure out which object is the + entry file is somewhat hokey. */ + /* NOTE: cagney/2003-01-10: If there is a way of disabling this test + then it should probably be moved to before the ->prev_p test, + above. */ + if (inside_entry_file (get_frame_pc (next_frame))) + return NULL; + + /* If any of the old frame initialization methods are around, use + the legacy get_prev_frame method. Just don't try to unwind a + sentinel frame using that method - it doesn't work. All sentinal + frames use the new unwind code. */ + if ((DEPRECATED_INIT_FRAME_PC_P () + || DEPRECATED_INIT_FRAME_PC_FIRST_P () + || INIT_EXTRA_FRAME_INFO_P () + || FRAME_CHAIN_P ()) + && next_frame->level >= 0) + return legacy_get_prev_frame (next_frame); + + /* Allocate the new frame but do not wire it in to the frame chain. + Some (bad) code in INIT_FRAME_EXTRA_INFO tries to look along + frame->next to pull some fancy tricks (of course such code is, by + definition, recursive). Try to prevent it. + + There is no reason to worry about memory leaks, should the + remainder of the function fail. The allocated memory will be + quickly reclaimed when the frame cache is flushed, and the `we've + been here before' check above will stop repeated memory + allocation calls. */ + prev_frame = FRAME_OBSTACK_ZALLOC (struct frame_info); + prev_frame->level = next_frame->level + 1; + + /* Try to unwind the PC. If that doesn't work, assume we've reached + the oldest frame and simply return. Is there a better sentinal + value? The unwound PC value is then used to initialize the new + previous frame's type. + + Note that the pc-unwind is intentionally performed before the + frame chain. This is ok since, for old targets, both + frame_pc_unwind (nee, FRAME_SAVED_PC) and FRAME_CHAIN()) assume + NEXT_FRAME's data structures have already been initialized (using + INIT_EXTRA_FRAME_INFO) and hence the call order doesn't matter. + + By unwinding the PC first, it becomes possible to, in the case of + a dummy frame, avoid also unwinding the frame ID. This is + because (well ignoring the PPC) a dummy frame can be located + using NEXT_FRAME's frame ID. */ + + prev_frame->pc = frame_pc_unwind (next_frame); + if (prev_frame->pc == 0) + /* The allocated PREV_FRAME will be reclaimed when the frame + obstack is next purged. */ + return NULL; + prev_frame->type = frame_type_from_pc (prev_frame->pc); + + /* Set the unwind functions based on that identified PC. */ + prev_frame->unwind = frame_unwind_find_by_pc (current_gdbarch, + prev_frame->pc); + + /* FIXME: cagney/2003-01-13: A dummy frame doesn't need to unwind + the frame ID because the frame ID comes from the previous frame. + The other frames do though. True? */ + { + /* FIXME: cagney/2002-12-18: Instead of this hack, should just + save the frame ID directly. */ + struct frame_id id = frame_id_unwind (next_frame); + if (!frame_id_p (id)) + return NULL; + prev_frame->frame = id.base; + } + + /* Link it in. */ + next_frame->prev = prev_frame; + prev_frame->next = next_frame; + + /* FIXME: cagney/2002-01-19: This call will go away. Instead of + initializing extra info, all frames will use the frame_cache + (passed to the unwind functions) to store additional frame info. + Unfortunatly legacy targets can't use legacy_get_prev_frame() to + unwind the sentinel frame and, consequently, are forced to take + this code path and rely on the below call to INIT_EXTR_FRAME_INFO + to initialize the inner-most frame. */ + if (INIT_EXTRA_FRAME_INFO_P ()) + { + gdb_assert (prev_frame->level == 0); + INIT_EXTRA_FRAME_INFO (0, prev_frame); + } + + return prev_frame; +} + CORE_ADDR get_frame_pc (struct frame_info *frame) { @@ -1266,7 +1403,7 @@ deprecated_get_frame_saved_regs (struct frame_info *frame, if (frame->saved_regs == NULL) { frame->saved_regs = (CORE_ADDR *) - frame_obstack_alloc (SIZEOF_FRAME_SAVED_REGS); + frame_obstack_zalloc (SIZEOF_FRAME_SAVED_REGS); } if (saved_regs_addr == NULL) { @@ -1291,8 +1428,7 @@ get_frame_extra_info (struct frame_info *fi) struct frame_extra_info * frame_extra_info_zalloc (struct frame_info *fi, long size) { - fi->extra_info = frame_obstack_alloc (size); - memset (fi->extra_info, 0, size); + fi->extra_info = frame_obstack_zalloc (size); return fi->extra_info; } @@ -1300,6 +1436,7 @@ void deprecated_update_frame_pc_hack (struct frame_info *frame, CORE_ADDR pc) { /* See comment in "frame.h". */ + gdb_assert (frame->next != NULL); frame->pc = pc; } @@ -1311,7 +1448,92 @@ deprecated_update_frame_base_hack (struct frame_info *frame, CORE_ADDR base) } void +deprecated_set_frame_saved_regs_hack (struct frame_info *frame, + CORE_ADDR *saved_regs) +{ + frame->saved_regs = saved_regs; +} + +void +deprecated_set_frame_extra_info_hack (struct frame_info *frame, + struct frame_extra_info *extra_info) +{ + frame->extra_info = extra_info; +} + +void +deprecated_set_frame_next_hack (struct frame_info *fi, + struct frame_info *next) +{ + fi->next = next; +} + +void +deprecated_set_frame_prev_hack (struct frame_info *fi, + struct frame_info *prev) +{ + fi->prev = prev; +} + +struct context * +deprecated_get_frame_context (struct frame_info *fi) +{ + return fi->context; +} + +void +deprecated_set_frame_context (struct frame_info *fi, + struct context *context) +{ + fi->context = context; +} + +struct frame_info * +deprecated_frame_xmalloc (void) +{ + struct frame_info *frame = XMALLOC (struct frame_info); + memset (frame, 0, sizeof (struct frame_info)); + return frame; +} + +struct frame_info * +deprecated_frame_xmalloc_with_cleanup (long sizeof_saved_regs, + long sizeof_extra_info) +{ + struct frame_info *frame = deprecated_frame_xmalloc (); + make_cleanup (xfree, frame); + if (sizeof_saved_regs > 0) + { + frame->saved_regs = xcalloc (1, sizeof_saved_regs); + make_cleanup (xfree, frame->saved_regs); + } + if (sizeof_extra_info > 0) + { + frame->extra_info = xcalloc (1, sizeof_extra_info); + make_cleanup (xfree, frame->extra_info); + } + return frame; +} + +void _initialize_frame (void) { obstack_init (&frame_cache_obstack); + + /* FIXME: cagney/2003-01-19: This command needs a rename. Suggest + `set backtrace {past,beyond,...}-main'. Also suggest adding `set + backtrace ...-start' to control backtraces past start. The + problem with `below' is that it stops the `up' command. */ + + add_setshow_boolean_cmd ("backtrace-below-main", class_obscure, + &backtrace_below_main, "\ +Set whether backtraces should continue past \"main\".\n\ +Normally the caller of \"main\" is not of interest, so GDB will terminate\n\ +the backtrace at \"main\". Set this variable if you need to see the rest\n\ +of the stack trace.", "\ +Show whether backtraces should continue past \"main\".\n\ +Normally the caller of \"main\" is not of interest, so GDB will terminate\n\ +the backtrace at \"main\". Set this variable if you need to see the rest\n\ +of the stack trace.", + NULL, NULL, &setlist, &showlist); } |