/* Target-dependent code for the IA-64 for GDB, the GNU debugger.
Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008,
- 2009 Free Software Foundation, Inc.
+ 2009, 2010 Free Software Foundation, Inc.
This file is part of GDB.
SLOTNUM (`adress & 0x0f', value in the range <0..2>). We need to know
SLOTNUM in ia64_memory_remove_breakpoint.
+ There is one special case where we need to be extra careful:
+ L-X instructions, which are instructions that occupy 2 slots
+ (The L part is always in slot 1, and the X part is always in
+ slot 2). We must refuse to insert breakpoints for an address
+ that points at slot 2 of a bundle where an L-X instruction is
+ present, since there is logically no instruction at that address.
+ However, to make things more interesting, the opcode of L-X
+ instructions is located in slot 2. This means that, to insert
+ a breakpoint at an address that points to slot 1, we actually
+ need to write the breakpoint in slot 2! Slot 1 is actually
+ the extended operand, so writing the breakpoint there would not
+ have the desired effect. Another side-effect of this issue
+ is that we need to make sure that the shadow contents buffer
+ does save byte 15 of our instruction bundle (this is the tail
+ end of slot 2, which wouldn't be saved if we were to insert
+ the breakpoint in slot 1).
+
ia64 16-byte bundle layout:
| 5 bits | slot 0 with 41 bits | slot 1 with 41 bits | slot 2 with 41 bits |
The current addressing used by the code below:
original PC placed_address placed_size required covered
== bp_tgt->shadow_len reqd \subset covered
- 0xABCDE0 0xABCDE0 0xE <0x0...0x5> <0x0..0xD>
- 0xABCDE1 0xABCDE1 0xE <0x5...0xA> <0x1..0xE>
+ 0xABCDE0 0xABCDE0 0x10 <0x0...0x5> <0x0..0xF>
+ 0xABCDE1 0xABCDE1 0xF <0x5...0xA> <0x1..0xF>
0xABCDE2 0xABCDE2 0xE <0xA...0xF> <0x2..0xF>
-
+
+ L-X instructions are treated a little specially, as explained above:
+ 0xABCDE1 0xABCDE1 0xF <0xA...0xF> <0x1..0xF>
+
`objdump -d' and some other tools show a bit unjustified offsets:
original PC byte where starts the instruction objdump offset
0xABCDE0 0xABCDE0 0xABCDE0
{
CORE_ADDR addr = bp_tgt->placed_address;
gdb_byte bundle[BUNDLE_LEN];
- int slotnum = (int) (addr & 0x0f) / SLOT_MULTIPLIER;
+ int slotnum = (int) (addr & 0x0f) / SLOT_MULTIPLIER, shadow_slotnum;
long long instr_breakpoint;
int val;
int template;
breakpoint instruction bits region. */
cleanup = make_show_memory_breakpoints_cleanup (0);
val = target_read_memory (addr, bundle, BUNDLE_LEN);
+ if (val != 0)
+ {
+ do_cleanups (cleanup);
+ return val;
+ }
+
+ /* SHADOW_SLOTNUM saves the original slot number as expected by the caller
+ for addressing the SHADOW_CONTENTS placement. */
+ shadow_slotnum = slotnum;
- /* Slot number 2 may skip at most 2 bytes at the beginning. */
- bp_tgt->shadow_len = BUNDLE_LEN - 2;
+ /* Always cover the last byte of the bundle in case we are inserting
+ a breakpoint on an L-X instruction. */
+ bp_tgt->shadow_len = BUNDLE_LEN - shadow_slotnum;
+
+ template = extract_bit_field (bundle, 0, 5);
+ if (template_encoding_table[template][slotnum] == X)
+ {
+ /* X unit types can only be used in slot 2, and are actually
+ part of a 2-slot L-X instruction. We cannot break at this
+ address, as this is the second half of an instruction that
+ lives in slot 1 of that bundle. */
+ gdb_assert (slotnum == 2);
+ error (_("Can't insert breakpoint for non-existing slot X"));
+ }
+ if (template_encoding_table[template][slotnum] == L)
+ {
+ /* L unit types can only be used in slot 1. But the associated
+ opcode for that instruction is in slot 2, so bump the slot number
+ accordingly. */
+ gdb_assert (slotnum == 1);
+ slotnum = 2;
+ }
/* Store the whole bundle, except for the initial skipped bytes by the slot
number interpreted as bytes offset in PLACED_ADDRESS. */
- memcpy (bp_tgt->shadow_contents, bundle + slotnum, bp_tgt->shadow_len);
+ memcpy (bp_tgt->shadow_contents, bundle + shadow_slotnum, bp_tgt->shadow_len);
/* Re-read the same bundle as above except that, this time, read it in order
to compute the new bundle inside which we will be inserting the
adjacent placed breakpoints. It is due to our SHADOW_CONTENTS overlapping
the real breakpoint instruction bits region. */
make_show_memory_breakpoints_cleanup (1);
- val |= target_read_memory (addr, bundle, BUNDLE_LEN);
-
- /* Check for L type instruction in slot 1, if present then bump up the slot
- number to the slot 2. */
- template = extract_bit_field (bundle, 0, 5);
- if (slotnum == 1 && template_encoding_table[template][slotnum] == L)
- slotnum = 2;
+ val = target_read_memory (addr, bundle, BUNDLE_LEN);
+ if (val != 0)
+ {
+ do_cleanups (cleanup);
+ return val;
+ }
/* Breakpoints already present in the code will get deteacted and not get
reinserted by bp_loc_is_permanent. Multiple breakpoints at the same
bp_tgt->placed_size = bp_tgt->shadow_len;
- if (val == 0)
- val = target_write_memory (addr + slotnum, bundle + slotnum,
- bp_tgt->shadow_len);
+ val = target_write_memory (addr + shadow_slotnum, bundle + shadow_slotnum,
+ bp_tgt->shadow_len);
do_cleanups (cleanup);
return val;
{
CORE_ADDR addr = bp_tgt->placed_address;
gdb_byte bundle_mem[BUNDLE_LEN], bundle_saved[BUNDLE_LEN];
- int slotnum = (addr & 0x0f) / SLOT_MULTIPLIER;
+ int slotnum = (addr & 0x0f) / SLOT_MULTIPLIER, shadow_slotnum;
long long instr_breakpoint, instr_saved;
int val;
int template;
breakpoint instruction bits region. */
cleanup = make_show_memory_breakpoints_cleanup (1);
val = target_read_memory (addr, bundle_mem, BUNDLE_LEN);
+ if (val != 0)
+ {
+ do_cleanups (cleanup);
+ return val;
+ }
+
+ /* SHADOW_SLOTNUM saves the original slot number as expected by the caller
+ for addressing the SHADOW_CONTENTS placement. */
+ shadow_slotnum = slotnum;
- /* Check for L type instruction in slot 1, if present then bump up the slot
- number to the slot 2. */
template = extract_bit_field (bundle_mem, 0, 5);
- if (slotnum == 1 && template_encoding_table[template][slotnum] == L)
- slotnum = 2;
+ if (template_encoding_table[template][slotnum] == X)
+ {
+ /* X unit types can only be used in slot 2, and are actually
+ part of a 2-slot L-X instruction. We refuse to insert
+ breakpoints at this address, so there should be no reason
+ for us attempting to remove one there, except if the program's
+ code somehow got modified in memory. */
+ gdb_assert (slotnum == 2);
+ warning (_("Cannot remove breakpoint at address %s from non-existing "
+ "X-type slot, memory has changed underneath"),
+ paddress (gdbarch, bp_tgt->placed_address));
+ do_cleanups (cleanup);
+ return -1;
+ }
+ if (template_encoding_table[template][slotnum] == L)
+ {
+ /* L unit types can only be used in slot 1. But the breakpoint
+ was actually saved using slot 2, so update the slot number
+ accordingly. */
+ gdb_assert (slotnum == 1);
+ slotnum = 2;
+ }
- gdb_assert (bp_tgt->placed_size == BUNDLE_LEN - 2);
+ gdb_assert (bp_tgt->placed_size == BUNDLE_LEN - shadow_slotnum);
gdb_assert (bp_tgt->placed_size == bp_tgt->shadow_len);
instr_breakpoint = slotN_contents (bundle_mem, slotnum);
warning (_("Cannot remove breakpoint at address %s, "
"no break instruction at such address."),
paddress (gdbarch, bp_tgt->placed_address));
+ do_cleanups (cleanup);
return -1;
}
/* Extract the original saved instruction from SLOTNUM normalizing its
bit-shift for INSTR_SAVED. */
memcpy (bundle_saved, bundle_mem, BUNDLE_LEN);
- memcpy (bundle_saved + slotnum, bp_tgt->shadow_contents, bp_tgt->shadow_len);
+ memcpy (bundle_saved + shadow_slotnum, bp_tgt->shadow_contents,
+ bp_tgt->shadow_len);
instr_saved = slotN_contents (bundle_saved, slotnum);
- /* In BUNDLE_MEM be careful to modify only the bits belonging to SLOTNUM and
- never any other possibly also stored in SHADOW_CONTENTS. */
+ /* In BUNDLE_MEM, be careful to modify only the bits belonging to SLOTNUM
+ and not any of the other ones that are stored in SHADOW_CONTENTS. */
replace_slotN_contents (bundle_mem, instr_saved, slotnum);
- if (val == 0)
- val = target_write_memory (addr, bundle_mem, BUNDLE_LEN);
+ val = target_write_memory (addr, bundle_mem, BUNDLE_LEN);
do_cleanups (cleanup);
return val;
{
CORE_ADDR addr = *pcptr;
static gdb_byte bundle[BUNDLE_LEN];
- int slotnum = (int) (*pcptr & 0x0f) / SLOT_MULTIPLIER;
+ int slotnum = (int) (*pcptr & 0x0f) / SLOT_MULTIPLIER, shadow_slotnum;
long long instr_fetched;
int val;
int template;
if (val != 0)
return NULL;
+ /* SHADOW_SLOTNUM saves the original slot number as expected by the caller
+ for addressing the SHADOW_CONTENTS placement. */
+ shadow_slotnum = slotnum;
+
+ /* Cover always the last byte of the bundle for the L-X slot case. */
+ *lenptr = BUNDLE_LEN - shadow_slotnum;
+
/* Check for L type instruction in slot 1, if present then bump up the slot
number to the slot 2. */
template = extract_bit_field (bundle, 0, 5);
- if (slotnum == 1 && template_encoding_table[template][slotnum] == L)
- slotnum = 2;
+ if (template_encoding_table[template][slotnum] == X)
+ {
+ gdb_assert (slotnum == 2);
+ error (_("Can't insert breakpoint for non-existing slot X"));
+ }
+ if (template_encoding_table[template][slotnum] == L)
+ {
+ gdb_assert (slotnum == 1);
+ slotnum = 2;
+ }
/* A break instruction has its all its opcode bits cleared except for
the parameter value. For L+X slot pair we are at the X slot (slot 2) so
instr_fetched &= 0x1003ffffc0LL;
replace_slotN_contents (bundle, instr_fetched, slotnum);
- *lenptr = BUNDLE_LEN - 2;
-
- /* SLOTNUM is possibly already locally modified - use caller's *PCPTR. */
- return bundle + (*pcptr & 0x0f);
+ return bundle + shadow_slotnum;
}
static CORE_ADDR
ia64_frame_cache (this_frame, this_cache);
/* If outermost frame, mark with null frame id. */
- if (cache->base == 0)
- (*this_id) = null_frame_id;
- else
+ if (cache->base != 0)
(*this_id) = frame_id_build_special (cache->base, cache->pc, cache->bsp);
if (gdbarch_debug >= 1)
fprintf_unfiltered (gdb_stdlog,
{
struct gdbarch *gdbarch = get_frame_arch (this_frame);
enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
- struct frame_id id;
+ struct frame_id id = outer_frame_id;
char buf[8];
CORE_ADDR bsp;
-
libunwind_frame_this_id (this_frame, this_cache, &id);
- if (frame_id_eq (id, null_frame_id))
+ if (frame_id_eq (id, outer_frame_id))
{
- (*this_id) = null_frame_id;
+ (*this_id) = outer_frame_id;
return;
}
enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
char buf[8];
CORE_ADDR bsp;
- struct frame_id id;
+ struct frame_id id = outer_frame_id;
CORE_ADDR prev_ip;
libunwind_frame_this_id (this_frame, this_cache, &id);
- if (frame_id_eq (id, null_frame_id))
+ if (frame_id_eq (id, outer_frame_id))
{
- (*this_id) = null_frame_id;
+ (*this_id) = outer_frame_id;
return;
}
{
enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
struct obj_section *s;
+ gdb_byte buf[8];
s = find_pc_section (addr);
/* Normally, functions live inside a section that is executable.
So, if ADDR points to a non-executable section, then treat it
as a function descriptor and return the target address iff
- the target address itself points to a section that is executable. */
- if (s && (s->the_bfd_section->flags & SEC_CODE) == 0)
+ the target address itself points to a section that is executable.
+ Check first the memory of the whole length of 8 bytes is readable. */
+ if (s && (s->the_bfd_section->flags & SEC_CODE) == 0
+ && target_read_memory (addr, buf, 8) == 0)
{
- CORE_ADDR pc = read_memory_unsigned_integer (addr, 8, byte_order);
+ CORE_ADDR pc = extract_unsigned_integer (buf, 8, byte_order);
struct obj_section *pc_section = find_pc_section (pc);
if (pc_section && (pc_section->the_bfd_section->flags & SEC_CODE))