diff options
Diffstat (limited to 'gdb/frame.c')
| -rw-r--r-- | gdb/frame.c | 263 |
1 files changed, 135 insertions, 128 deletions
diff --git a/gdb/frame.c b/gdb/frame.c index d252d8a..a0cfc6f 100644 --- a/gdb/frame.c +++ b/gdb/frame.c @@ -31,6 +31,7 @@ #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" @@ -179,29 +180,11 @@ 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->unwind->reg (frame, &frame->unwind_cache, regnum, @@ -247,25 +230,11 @@ 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 @@ -317,17 +286,17 @@ 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 @@ -355,25 +324,9 @@ 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 @@ -463,6 +416,32 @@ 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; @@ -495,17 +474,43 @@ 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; } @@ -593,11 +598,11 @@ frame_saved_regs_register_unwind (struct frame_info *frame, void **cache, 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) { @@ -608,7 +613,7 @@ 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 { @@ -616,7 +621,7 @@ 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) { @@ -635,13 +640,13 @@ frame_saved_regs_register_unwind (struct frame_info *frame, void **cache, { regs[regnum] = frame_obstack_zalloc (REGISTER_RAW_SIZE (regnum)); - read_memory (frame->saved_regs[regnum], regs[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 } @@ -650,21 +655,11 @@ 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 @@ -684,7 +679,7 @@ frame_saved_regs_id_unwind (struct frame_info *next_frame, void **cache, /* 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 @@ -797,44 +792,50 @@ 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) + for (frame = get_next_frame (frame); + frame_relative_level (frame) >= 0; + frame = get_next_frame (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) - { - 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; } } @@ -884,6 +885,7 @@ create_new_frame (CORE_ADDR addr, CORE_ADDR pc) fi->frame = addr; fi->pc = pc; + fi->next = create_sentinel_frame (current_regcache); fi->type = frame_type_from_pc (pc); if (INIT_EXTRA_FRAME_INFO_P ()) @@ -896,12 +898,16 @@ create_new_frame (CORE_ADDR addr, CORE_ADDR pc) } /* 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. */ @@ -1415,6 +1421,7 @@ 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; } |