-/* Cache and manage the values of registers for GDB, the GNU debugger.
+/* 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.
#include "value.h"
#include "inferior.h" /* for inferior_ptid */
#include "regcache.h"
+#include "gdb_assert.h"
+
+/* Return a frame uniq ID that can be used to, later re-find the
+ frame. */
+
+void
+get_frame_id (struct frame_info *fi, struct frame_id *id)
+{
+ if (fi == NULL)
+ {
+ id->base = 0;
+ id->pc = 0;
+ }
+ else
+ {
+ id->base = FRAME_FP (fi);
+ id->pc = fi->pc;
+ }
+}
+
+struct frame_info *
+frame_find_by_id (struct frame_id id)
+{
+ struct frame_info *frame;
+
+ /* ZERO denotes the null frame, let the caller decide what to do
+ about it. Should it instead return get_current_frame()? */
+ if (id.base == 0 && id.pc == 0)
+ return NULL;
+
+ for (frame = get_current_frame ();
+ frame != NULL;
+ frame = get_prev_frame (frame))
+ {
+ if (INNER_THAN (FRAME_FP (frame), id.base))
+ /* ``inner/current < frame < id.base''. Keep looking along
+ the frame chain. */
+ continue;
+ if (INNER_THAN (id.base, FRAME_FP (frame)))
+ /* ``inner/current < id.base < frame''. Oops, gone past it.
+ Just give up. */
+ return NULL;
+ /* FIXME: cagney/2002-04-21: This isn't sufficient. It should
+ use id.pc to check that the two frames belong to the same
+ function. Otherwise we'll do things like match dummy frames
+ or mis-match frameless functions. However, until someone
+ notices, stick with the existing behavour. */
+ return frame;
+ }
+ return NULL;
+}
/* FIND_SAVED_REGISTER ()
return addr;
}
-/* DEFAULT_GET_SAVED_REGISTER ()
-
- Find register number REGNUM relative to FRAME and put its (raw,
- target format) contents in *RAW_BUFFER. Set *OPTIMIZED if the
- variable was optimized out (and thus can't be fetched). Set *LVAL
- to lval_memory, lval_register, or not_lval, depending on whether
- the value was fetched from memory, from a register, or in a strange
- and non-modifiable way (e.g. a frame pointer which was calculated
- rather than fetched). Set *ADDRP to the address, either in memory
- on as a REGISTER_BYTE offset into the registers array.
-
- Note that this implementation never sets *LVAL to not_lval. But
- it can be replaced by defining GET_SAVED_REGISTER and supplying
- your own.
-
- The argument RAW_BUFFER must point to aligned memory. */
-
-static void
-default_get_saved_register (char *raw_buffer,
- int *optimized,
- CORE_ADDR *addrp,
- struct frame_info *frame,
- int regnum,
- enum lval_type *lval)
+void
+frame_register_unwind (struct frame_info *frame, int regnum,
+ int *optimizedp, enum lval_type *lvalp,
+ CORE_ADDR *addrp, int *realnump, void *bufferp)
+{
+ struct frame_unwind_cache *cache;
+
+ /* 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); */
+
+ /* 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;
+ *addrp = 0;
+ /* 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)
+ read_register_gen (regnum, bufferp);
+ return;
+ }
+
+ /* Ask this frame to unwind its register. */
+ frame->register_unwind (frame, &frame->register_unwind_cache, regnum,
+ optimizedp, lvalp, addrp, realnump, bufferp);
+}
+
+
+void
+generic_unwind_get_saved_register (char *raw_buffer,
+ int *optimizedp,
+ CORE_ADDR *addrp,
+ struct frame_info *frame,
+ int regnum,
+ enum lval_type *lvalp)
{
- CORE_ADDR addr;
+ int optimizedx;
+ CORE_ADDR addrx;
+ int realnumx;
+ enum lval_type lvalx;
if (!target_has_registers)
error ("No registers.");
- /* Normal systems don't optimize out things with register numbers. */
- if (optimized != NULL)
- *optimized = 0;
- addr = find_saved_register (frame, regnum);
- if (addr != 0)
- {
- if (lval != NULL)
- *lval = lval_memory;
- if (regnum == SP_REGNUM)
- {
- if (raw_buffer != NULL)
- {
- /* Put it back in target format. */
- store_address (raw_buffer, REGISTER_RAW_SIZE (regnum),
- (LONGEST) addr);
- }
- if (addrp != NULL)
- *addrp = 0;
- return;
- }
- if (raw_buffer != NULL)
- target_read_memory (addr, raw_buffer, REGISTER_RAW_SIZE (regnum));
- }
+ /* Keep things simple, ensure that all the pointers (except valuep)
+ are non NULL. */
+ if (optimizedp == NULL)
+ optimizedp = &optimizedx;
+ if (lvalp == NULL)
+ lvalp = &lvalx;
+ 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
- {
- if (lval != NULL)
- *lval = lval_register;
- addr = REGISTER_BYTE (regnum);
- if (raw_buffer != NULL)
- read_register_gen (regnum, raw_buffer);
- }
- if (addrp != NULL)
- *addrp = addr;
+ frame_register_unwind (frame->next, regnum, optimizedp, lvalp, addrp,
+ &realnumx, raw_buffer);
}
-#if !defined (GET_SAVED_REGISTER)
-#define GET_SAVED_REGISTER(raw_buffer, optimized, addrp, frame, regnum, lval) \
- default_get_saved_register(raw_buffer, optimized, addrp, frame, regnum, lval)
-#endif
-
void
get_saved_register (char *raw_buffer,
int *optimized,
get_saved_register (myaddr, &optim, (CORE_ADDR *) NULL, frame,
regnum, (enum lval_type *) NULL);
- /* FIXME: cagney/2002-04-10: This test is just bogus. It is no
- indication of the validity of the register. The value could
- easily be found (on the stack) even though the corresponding
- register isn't available. */
+ /* FIXME: cagney/2002-05-15: This test, is just bogus.
+
+ It indicates that the target failed to supply a value for a
+ register because it was "not available" at this time. Problem
+ is, the target still has the register and so get saved_register()
+ may be returning a value saved on the stack. */
+
if (register_cached (regnum) < 0)
return 0; /* register value not available */
projects / deliverable / binutils-gdb.git / blobdiff