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2011-11-25  Uros Bizjak  <ubizjak@gmail.com> 

* alpha-tdep.c (br_opcode): New.
	(ldl_l_opcode, ldq_l_opcode, stl_c_opcode, stq_c_opcode): Ditto.
	(alpha_deal_with_atomic_sequence): New function.
	(alpha_gdbarch_init): Handle single stepping of atomic sequences
	with alpha_deal_with_atomic_sequence.
This commit is contained in:
Ulrich Weigand 2011-11-25 17:05:42 +00:00
parent 0c7533d365
commit 46ad3598b7
2 changed files with 100 additions and 0 deletions
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8
gdb/ChangeLog
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@ -1,3 +1,11 @@
2011-11-25  Uros Bizjak  <ubizjak@gmail.com>
* alpha-tdep.c (br_opcode): New.
(ldl_l_opcode, ldq_l_opcode, stl_c_opcode, stq_c_opcode): Ditto.
(alpha_deal_with_atomic_sequence): New function.
(alpha_gdbarch_init): Handle single stepping of atomic sequences
with alpha_deal_with_atomic_sequence.
2011-11-24 Tristan Gingold <gingold@adacore.com>
* machoread.c (oso_el): Remove num_Sections, symbols, offsets

92
gdb/alpha-tdep.c
View File

@ -65,6 +65,7 @@ static const int stq_opcode = 0x2d;
/* Branch instruction format */
#define BR_RA(insn) MEM_RA(insn)
static const int br_opcode = 0x30;
static const int bne_opcode = 0x3d;
/* Operate instruction format */
@ -761,6 +762,94 @@ alpha_skip_prologue (struct gdbarch *gdbarch, CORE_ADDR pc)
return pc + offset;
}
static const int ldl_l_opcode = 0x2a;
static const int ldq_l_opcode = 0x2b;
static const int stl_c_opcode = 0x2e;
static const int stq_c_opcode = 0x2f;
/* Checks for an atomic sequence of instructions beginning with a LDL_L/LDQ_L
instruction and ending with a STL_C/STQ_C instruction. If such a sequence
is found, attempt to step through it. A breakpoint is placed at the end of
the sequence. */
int
alpha_deal_with_atomic_sequence (struct frame_info *frame)
{
struct gdbarch *gdbarch = get_frame_arch (frame);
struct address_space *aspace = get_frame_address_space (frame);
CORE_ADDR pc = get_frame_pc (frame);
CORE_ADDR breaks[2] = {-1, -1};
CORE_ADDR loc = pc;
CORE_ADDR closing_insn; /* Instruction that closes the atomic sequence. */
unsigned int insn = alpha_read_insn (gdbarch, loc);
int insn_count;
int index;
int last_breakpoint = 0; /* Defaults to 0 (no breakpoints placed). */
const int atomic_sequence_length = 16; /* Instruction sequence length. */
int bc_insn_count = 0; /* Conditional branch instruction count. */
/* Assume all atomic sequences start with a LDL_L/LDQ_L instruction. */
if (INSN_OPCODE (insn) != ldl_l_opcode
&& INSN_OPCODE (insn) != ldq_l_opcode)
return 0;
/* Assume that no atomic sequence is longer than "atomic_sequence_length"
instructions. */
for (insn_count = 0; insn_count < atomic_sequence_length; ++insn_count)
{
loc += ALPHA_INSN_SIZE;
insn = alpha_read_insn (gdbarch, loc);
/* Assume that there is at most one branch in the atomic
sequence. If a branch is found, put a breakpoint in
its destination address. */
if (INSN_OPCODE (insn) >= br_opcode)
{
int immediate = (insn & 0x001fffff) << 2;
immediate = (immediate ^ 0x400000) - 0x400000;
if (bc_insn_count >= 1)
return 0; /* More than one branch found, fallback
to the standard single-step code. */
breaks[1] = loc + ALPHA_INSN_SIZE + immediate;
bc_insn_count++;
last_breakpoint++;
}
if (INSN_OPCODE (insn) == stl_c_opcode
|| INSN_OPCODE (insn) == stq_c_opcode)
break;
}
/* Assume that the atomic sequence ends with a STL_C/STQ_C instruction. */
if (INSN_OPCODE (insn) != stl_c_opcode
&& INSN_OPCODE (insn) != stq_c_opcode)
return 0;
closing_insn = loc;
loc += ALPHA_INSN_SIZE;
/* Insert a breakpoint right after the end of the atomic sequence. */
breaks[0] = loc;
/* Check for duplicated breakpoints. Check also for a breakpoint
placed (branch instruction's destination) anywhere in sequence. */
if (last_breakpoint
&& (breaks[1] == breaks[0]
|| (breaks[1] >= pc && breaks[1] <= closing_insn)))
last_breakpoint = 0;
/* Effectively inserts the breakpoints. */
for (index = 0; index <= last_breakpoint; index++)
insert_single_step_breakpoint (gdbarch, aspace, breaks[index]);
return 1;
}
/* Figure out where the longjmp will land.
We expect the first arg to be a pointer to the jmp_buf structure from
@ -1749,6 +1838,9 @@ alpha_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
set_gdbarch_decr_pc_after_break (gdbarch, ALPHA_INSN_SIZE);
set_gdbarch_cannot_step_breakpoint (gdbarch, 1);
/* Handles single stepping of atomic sequences. */
set_gdbarch_software_single_step (gdbarch, alpha_deal_with_atomic_sequence);
/* Hook in ABI-specific overrides, if they have been registered. */
gdbarch_init_osabi (info, gdbarch);