mirror of
https://sourceware.org/git/binutils-gdb.git
synced 2024-11-24 10:35:12 +08:00
542 lines
14 KiB
C
542 lines
14 KiB
C
/* Functions for manipulating expressions designed to be executed on the agent
|
||
Copyright 1998, 2000 Free Software Foundation, Inc.
|
||
|
||
This file is part of GDB.
|
||
|
||
This program is free software; you can redistribute it and/or modify
|
||
it under the terms of the GNU General Public License as published by
|
||
the Free Software Foundation; either version 2 of the License, or
|
||
(at your option) any later version.
|
||
|
||
This program is distributed in the hope that it will be useful,
|
||
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||
GNU General Public License for more details.
|
||
|
||
You should have received a copy of the GNU General Public License
|
||
along with this program; if not, write to the Free Software
|
||
Foundation, Inc., 59 Temple Place - Suite 330,
|
||
Boston, MA 02111-1307, USA. */
|
||
|
||
/* Despite what the above comment says about this file being part of
|
||
GDB, we would like to keep these functions free of GDB
|
||
dependencies, since we want to be able to use them in contexts
|
||
outside of GDB (test suites, the stub, etc.) */
|
||
|
||
#include "defs.h"
|
||
#include "ax.h"
|
||
|
||
#include "value.h"
|
||
|
||
static void grow_expr (struct agent_expr *x, int n);
|
||
|
||
static void append_const (struct agent_expr *x, LONGEST val, int n);
|
||
|
||
static LONGEST read_const (struct agent_expr *x, int o, int n);
|
||
|
||
static void generic_ext (struct agent_expr *x, enum agent_op op, int n);
|
||
|
||
/* Functions for building expressions. */
|
||
|
||
/* Allocate a new, empty agent expression. */
|
||
struct agent_expr *
|
||
new_agent_expr (CORE_ADDR scope)
|
||
{
|
||
struct agent_expr *x = xmalloc (sizeof (*x));
|
||
x->len = 0;
|
||
x->size = 1; /* Change this to a larger value once
|
||
reallocation code is tested. */
|
||
x->buf = xmalloc (x->size);
|
||
x->scope = scope;
|
||
|
||
return x;
|
||
}
|
||
|
||
/* Free a agent expression. */
|
||
void
|
||
free_agent_expr (struct agent_expr *x)
|
||
{
|
||
free (x->buf);
|
||
free (x);
|
||
}
|
||
|
||
static void
|
||
do_free_agent_expr_cleanup (void *x)
|
||
{
|
||
free_agent_expr (x);
|
||
}
|
||
|
||
struct cleanup *
|
||
make_cleanup_free_agent_expr (struct agent_expr *x)
|
||
{
|
||
return make_cleanup (do_free_agent_expr_cleanup, x);
|
||
}
|
||
|
||
|
||
/* Make sure that X has room for at least N more bytes. This doesn't
|
||
affect the length, just the allocated size. */
|
||
static void
|
||
grow_expr (struct agent_expr *x, int n)
|
||
{
|
||
if (x->len + n > x->size)
|
||
{
|
||
x->size *= 2;
|
||
if (x->size < x->len + n)
|
||
x->size = x->len + n + 10;
|
||
x->buf = xrealloc (x->buf, x->size);
|
||
}
|
||
}
|
||
|
||
|
||
/* Append the low N bytes of VAL as an N-byte integer to the
|
||
expression X, in big-endian order. */
|
||
static void
|
||
append_const (struct agent_expr *x, LONGEST val, int n)
|
||
{
|
||
int i;
|
||
|
||
grow_expr (x, n);
|
||
for (i = n - 1; i >= 0; i--)
|
||
{
|
||
x->buf[x->len + i] = val & 0xff;
|
||
val >>= 8;
|
||
}
|
||
x->len += n;
|
||
}
|
||
|
||
|
||
/* Extract an N-byte big-endian unsigned integer from expression X at
|
||
offset O. */
|
||
static LONGEST
|
||
read_const (struct agent_expr *x, int o, int n)
|
||
{
|
||
int i;
|
||
LONGEST accum = 0;
|
||
|
||
/* Make sure we're not reading off the end of the expression. */
|
||
if (o + n > x->len)
|
||
error ("GDB bug: ax-general.c (read_const): incomplete constant");
|
||
|
||
for (i = 0; i < n; i++)
|
||
accum = (accum << 8) | x->buf[o + i];
|
||
|
||
return accum;
|
||
}
|
||
|
||
|
||
/* Append a simple operator OP to EXPR. */
|
||
void
|
||
ax_simple (struct agent_expr *x, enum agent_op op)
|
||
{
|
||
grow_expr (x, 1);
|
||
x->buf[x->len++] = op;
|
||
}
|
||
|
||
|
||
/* Append a sign-extension or zero-extension instruction to EXPR, to
|
||
extend an N-bit value. */
|
||
static void
|
||
generic_ext (struct agent_expr *x, enum agent_op op, int n)
|
||
{
|
||
/* N must fit in a byte. */
|
||
if (n < 0 || n > 255)
|
||
error ("GDB bug: ax-general.c (generic_ext): bit count out of range");
|
||
/* That had better be enough range. */
|
||
if (sizeof (LONGEST) * 8 > 255)
|
||
error ("GDB bug: ax-general.c (generic_ext): opcode has inadequate range");
|
||
|
||
grow_expr (x, 2);
|
||
x->buf[x->len++] = op;
|
||
x->buf[x->len++] = n;
|
||
}
|
||
|
||
|
||
/* Append a sign-extension instruction to EXPR, to extend an N-bit value. */
|
||
void
|
||
ax_ext (struct agent_expr *x, int n)
|
||
{
|
||
generic_ext (x, aop_ext, n);
|
||
}
|
||
|
||
|
||
/* Append a zero-extension instruction to EXPR, to extend an N-bit value. */
|
||
void
|
||
ax_zero_ext (struct agent_expr *x, int n)
|
||
{
|
||
generic_ext (x, aop_zero_ext, n);
|
||
}
|
||
|
||
|
||
/* Append a trace_quick instruction to EXPR, to record N bytes. */
|
||
void
|
||
ax_trace_quick (struct agent_expr *x, int n)
|
||
{
|
||
/* N must fit in a byte. */
|
||
if (n < 0 || n > 255)
|
||
error ("GDB bug: ax-general.c (ax_trace_quick): size out of range for trace_quick");
|
||
|
||
grow_expr (x, 2);
|
||
x->buf[x->len++] = aop_trace_quick;
|
||
x->buf[x->len++] = n;
|
||
}
|
||
|
||
|
||
/* Append a goto op to EXPR. OP is the actual op (must be aop_goto or
|
||
aop_if_goto). We assume we don't know the target offset yet,
|
||
because it's probably a forward branch, so we leave space in EXPR
|
||
for the target, and return the offset in EXPR of that space, so we
|
||
can backpatch it once we do know the target offset. Use ax_label
|
||
to do the backpatching. */
|
||
int
|
||
ax_goto (struct agent_expr *x, enum agent_op op)
|
||
{
|
||
grow_expr (x, 3);
|
||
x->buf[x->len + 0] = op;
|
||
x->buf[x->len + 1] = 0xff;
|
||
x->buf[x->len + 2] = 0xff;
|
||
x->len += 3;
|
||
return x->len - 2;
|
||
}
|
||
|
||
/* Suppose a given call to ax_goto returns some value PATCH. When you
|
||
know the offset TARGET that goto should jump to, call
|
||
ax_label (EXPR, PATCH, TARGET)
|
||
to patch TARGET into the ax_goto instruction. */
|
||
void
|
||
ax_label (struct agent_expr *x, int patch, int target)
|
||
{
|
||
/* Make sure the value is in range. Don't accept 0xffff as an
|
||
offset; that's our magic sentinel value for unpatched branches. */
|
||
if (target < 0 || target >= 0xffff)
|
||
error ("GDB bug: ax-general.c (ax_label): label target out of range");
|
||
|
||
x->buf[patch] = (target >> 8) & 0xff;
|
||
x->buf[patch + 1] = target & 0xff;
|
||
}
|
||
|
||
|
||
/* Assemble code to push a constant on the stack. */
|
||
void
|
||
ax_const_l (struct agent_expr *x, LONGEST l)
|
||
{
|
||
static enum agent_op ops[]
|
||
=
|
||
{aop_const8, aop_const16, aop_const32, aop_const64};
|
||
int size;
|
||
int op;
|
||
|
||
/* How big is the number? 'op' keeps track of which opcode to use.
|
||
Notice that we don't really care whether the original number was
|
||
signed or unsigned; we always reproduce the value exactly, and
|
||
use the shortest representation. */
|
||
for (op = 0, size = 8; size < 64; size *= 2, op++)
|
||
if (-((LONGEST) 1 << size) <= l && l < ((LONGEST) 1 << size))
|
||
break;
|
||
|
||
/* Emit the right opcode... */
|
||
ax_simple (x, ops[op]);
|
||
|
||
/* Emit the low SIZE bytes as an unsigned number. We know that
|
||
sign-extending this will yield l. */
|
||
append_const (x, l, size / 8);
|
||
|
||
/* Now, if it was negative, and not full-sized, sign-extend it. */
|
||
if (l < 0 && size < 64)
|
||
ax_ext (x, size);
|
||
}
|
||
|
||
|
||
void
|
||
ax_const_d (struct agent_expr *x, LONGEST d)
|
||
{
|
||
/* FIXME: floating-point support not present yet. */
|
||
error ("GDB bug: ax-general.c (ax_const_d): floating point not supported yet");
|
||
}
|
||
|
||
|
||
/* Assemble code to push the value of register number REG on the
|
||
stack. */
|
||
void
|
||
ax_reg (struct agent_expr *x, int reg)
|
||
{
|
||
/* Make sure the register number is in range. */
|
||
if (reg < 0 || reg > 0xffff)
|
||
error ("GDB bug: ax-general.c (ax_reg): register number out of range");
|
||
grow_expr (x, 3);
|
||
x->buf[x->len] = aop_reg;
|
||
x->buf[x->len + 1] = (reg >> 8) & 0xff;
|
||
x->buf[x->len + 2] = (reg) & 0xff;
|
||
x->len += 3;
|
||
}
|
||
|
||
|
||
|
||
/* Functions for disassembling agent expressions, and otherwise
|
||
debugging the expression compiler. */
|
||
|
||
struct aop_map aop_map[] =
|
||
{
|
||
{0, 0, 0, 0, 0},
|
||
{"float", 0, 0, 0, 0}, /* 0x01 */
|
||
{"add", 0, 0, 2, 1}, /* 0x02 */
|
||
{"sub", 0, 0, 2, 1}, /* 0x03 */
|
||
{"mul", 0, 0, 2, 1}, /* 0x04 */
|
||
{"div_signed", 0, 0, 2, 1}, /* 0x05 */
|
||
{"div_unsigned", 0, 0, 2, 1}, /* 0x06 */
|
||
{"rem_signed", 0, 0, 2, 1}, /* 0x07 */
|
||
{"rem_unsigned", 0, 0, 2, 1}, /* 0x08 */
|
||
{"lsh", 0, 0, 2, 1}, /* 0x09 */
|
||
{"rsh_signed", 0, 0, 2, 1}, /* 0x0a */
|
||
{"rsh_unsigned", 0, 0, 2, 1}, /* 0x0b */
|
||
{"trace", 0, 0, 2, 0}, /* 0x0c */
|
||
{"trace_quick", 1, 0, 1, 1}, /* 0x0d */
|
||
{"log_not", 0, 0, 1, 1}, /* 0x0e */
|
||
{"bit_and", 0, 0, 2, 1}, /* 0x0f */
|
||
{"bit_or", 0, 0, 2, 1}, /* 0x10 */
|
||
{"bit_xor", 0, 0, 2, 1}, /* 0x11 */
|
||
{"bit_not", 0, 0, 1, 1}, /* 0x12 */
|
||
{"equal", 0, 0, 2, 1}, /* 0x13 */
|
||
{"less_signed", 0, 0, 2, 1}, /* 0x14 */
|
||
{"less_unsigned", 0, 0, 2, 1}, /* 0x15 */
|
||
{"ext", 1, 0, 1, 1}, /* 0x16 */
|
||
{"ref8", 0, 8, 1, 1}, /* 0x17 */
|
||
{"ref16", 0, 16, 1, 1}, /* 0x18 */
|
||
{"ref32", 0, 32, 1, 1}, /* 0x19 */
|
||
{"ref64", 0, 64, 1, 1}, /* 0x1a */
|
||
{"ref_float", 0, 0, 1, 1}, /* 0x1b */
|
||
{"ref_double", 0, 0, 1, 1}, /* 0x1c */
|
||
{"ref_long_double", 0, 0, 1, 1}, /* 0x1d */
|
||
{"l_to_d", 0, 0, 1, 1}, /* 0x1e */
|
||
{"d_to_l", 0, 0, 1, 1}, /* 0x1f */
|
||
{"if_goto", 2, 0, 1, 0}, /* 0x20 */
|
||
{"goto", 2, 0, 0, 0}, /* 0x21 */
|
||
{"const8", 1, 8, 0, 1}, /* 0x22 */
|
||
{"const16", 2, 16, 0, 1}, /* 0x23 */
|
||
{"const32", 4, 32, 0, 1}, /* 0x24 */
|
||
{"const64", 8, 64, 0, 1}, /* 0x25 */
|
||
{"reg", 2, 0, 0, 1}, /* 0x26 */
|
||
{"end", 0, 0, 0, 0}, /* 0x27 */
|
||
{"dup", 0, 0, 1, 2}, /* 0x28 */
|
||
{"pop", 0, 0, 1, 0}, /* 0x29 */
|
||
{"zero_ext", 1, 0, 1, 1}, /* 0x2a */
|
||
{"swap", 0, 0, 2, 2}, /* 0x2b */
|
||
{0, 0, 0, 0, 0}, /* 0x2c */
|
||
{0, 0, 0, 0, 0}, /* 0x2d */
|
||
{0, 0, 0, 0, 0}, /* 0x2e */
|
||
{0, 0, 0, 0, 0}, /* 0x2f */
|
||
{"trace16", 2, 0, 1, 1}, /* 0x30 */
|
||
};
|
||
|
||
|
||
/* Disassemble the expression EXPR, writing to F. */
|
||
void
|
||
ax_print (struct ui_file *f, struct agent_expr *x)
|
||
{
|
||
int i;
|
||
int is_float = 0;
|
||
|
||
/* Check the size of the name array against the number of entries in
|
||
the enum, to catch additions that people didn't sync. */
|
||
if ((sizeof (aop_map) / sizeof (aop_map[0]))
|
||
!= aop_last)
|
||
error ("GDB bug: ax-general.c (ax_print): opcode map out of sync");
|
||
|
||
for (i = 0; i < x->len;)
|
||
{
|
||
enum agent_op op = x->buf[i];
|
||
|
||
if (op >= (sizeof (aop_map) / sizeof (aop_map[0]))
|
||
|| !aop_map[op].name)
|
||
{
|
||
fprintf_filtered (f, "%3d <bad opcode %02x>\n", i, op);
|
||
i++;
|
||
continue;
|
||
}
|
||
if (i + 1 + aop_map[op].op_size > x->len)
|
||
{
|
||
fprintf_filtered (f, "%3d <incomplete opcode %s>\n",
|
||
i, aop_map[op].name);
|
||
break;
|
||
}
|
||
|
||
fprintf_filtered (f, "%3d %s", i, aop_map[op].name);
|
||
if (aop_map[op].op_size > 0)
|
||
{
|
||
fputs_filtered (" ", f);
|
||
|
||
print_longest (f, 'd', 0,
|
||
read_const (x, i + 1, aop_map[op].op_size));
|
||
}
|
||
fprintf_filtered (f, "\n");
|
||
i += 1 + aop_map[op].op_size;
|
||
|
||
is_float = (op == aop_float);
|
||
}
|
||
}
|
||
|
||
|
||
/* Given an agent expression AX, fill in an agent_reqs structure REQS
|
||
describing it. */
|
||
void
|
||
ax_reqs (struct agent_expr *ax, struct agent_reqs *reqs)
|
||
{
|
||
int i;
|
||
int height;
|
||
|
||
/* Bit vector for registers used. */
|
||
int reg_mask_len = 1;
|
||
unsigned char *reg_mask = xmalloc (reg_mask_len * sizeof (reg_mask[0]));
|
||
|
||
/* Jump target table. targets[i] is non-zero iff there is a jump to
|
||
offset i. */
|
||
char *targets = (char *) alloca (ax->len * sizeof (targets[0]));
|
||
|
||
/* Instruction boundary table. boundary[i] is non-zero iff an
|
||
instruction starts at offset i. */
|
||
char *boundary = (char *) alloca (ax->len * sizeof (boundary[0]));
|
||
|
||
/* Stack height record. iff either targets[i] or boundary[i] is
|
||
non-zero, heights[i] is the height the stack should have before
|
||
executing the bytecode at that point. */
|
||
int *heights = (int *) alloca (ax->len * sizeof (heights[0]));
|
||
|
||
/* Pointer to a description of the present op. */
|
||
struct aop_map *op;
|
||
|
||
memset (reg_mask, 0, reg_mask_len * sizeof (reg_mask[0]));
|
||
memset (targets, 0, ax->len * sizeof (targets[0]));
|
||
memset (boundary, 0, ax->len * sizeof (boundary[0]));
|
||
|
||
reqs->max_height = reqs->min_height = height = 0;
|
||
reqs->flaw = agent_flaw_none;
|
||
reqs->max_data_size = 0;
|
||
|
||
for (i = 0; i < ax->len; i += 1 + op->op_size)
|
||
{
|
||
if (ax->buf[i] > (sizeof (aop_map) / sizeof (aop_map[0])))
|
||
{
|
||
reqs->flaw = agent_flaw_bad_instruction;
|
||
free (reg_mask);
|
||
return;
|
||
}
|
||
|
||
op = &aop_map[ax->buf[i]];
|
||
|
||
if (!op->name)
|
||
{
|
||
reqs->flaw = agent_flaw_bad_instruction;
|
||
free (reg_mask);
|
||
return;
|
||
}
|
||
|
||
if (i + 1 + op->op_size > ax->len)
|
||
{
|
||
reqs->flaw = agent_flaw_incomplete_instruction;
|
||
free (reg_mask);
|
||
return;
|
||
}
|
||
|
||
/* If this instruction is a jump target, does the current stack
|
||
height match the stack height at the jump source? */
|
||
if (targets[i] && (heights[i] != height))
|
||
{
|
||
reqs->flaw = agent_flaw_height_mismatch;
|
||
free (reg_mask);
|
||
return;
|
||
}
|
||
|
||
boundary[i] = 1;
|
||
heights[i] = height;
|
||
|
||
height -= op->consumed;
|
||
if (height < reqs->min_height)
|
||
reqs->min_height = height;
|
||
height += op->produced;
|
||
if (height > reqs->max_height)
|
||
reqs->max_height = height;
|
||
|
||
if (op->data_size > reqs->max_data_size)
|
||
reqs->max_data_size = op->data_size;
|
||
|
||
/* For jump instructions, check that the target is a valid
|
||
offset. If it is, record the fact that that location is a
|
||
jump target, and record the height we expect there. */
|
||
if (aop_goto == op - aop_map
|
||
|| aop_if_goto == op - aop_map)
|
||
{
|
||
int target = read_const (ax, i + 1, 2);
|
||
if (target < 0 || target >= ax->len)
|
||
{
|
||
reqs->flaw = agent_flaw_bad_jump;
|
||
free (reg_mask);
|
||
return;
|
||
}
|
||
/* Have we already found other jumps to the same location? */
|
||
else if (targets[target])
|
||
{
|
||
if (heights[i] != height)
|
||
{
|
||
reqs->flaw = agent_flaw_height_mismatch;
|
||
free (reg_mask);
|
||
return;
|
||
}
|
||
}
|
||
else
|
||
{
|
||
targets[target] = 1;
|
||
heights[target] = height;
|
||
}
|
||
}
|
||
|
||
/* For unconditional jumps with a successor, check that the
|
||
successor is a target, and pick up its stack height. */
|
||
if (aop_goto == op - aop_map
|
||
&& i + 3 < ax->len)
|
||
{
|
||
if (!targets[i + 3])
|
||
{
|
||
reqs->flaw = agent_flaw_hole;
|
||
free (reg_mask);
|
||
return;
|
||
}
|
||
|
||
height = heights[i + 3];
|
||
}
|
||
|
||
/* For reg instructions, record the register in the bit mask. */
|
||
if (aop_reg == op - aop_map)
|
||
{
|
||
int reg = read_const (ax, i + 1, 2);
|
||
int byte = reg / 8;
|
||
|
||
/* Grow the bit mask if necessary. */
|
||
if (byte >= reg_mask_len)
|
||
{
|
||
/* It's not appropriate to double here. This isn't a
|
||
string buffer. */
|
||
int new_len = byte + 1;
|
||
reg_mask = xrealloc (reg_mask,
|
||
new_len * sizeof (reg_mask[0]));
|
||
memset (reg_mask + reg_mask_len, 0,
|
||
(new_len - reg_mask_len) * sizeof (reg_mask[0]));
|
||
reg_mask_len = new_len;
|
||
}
|
||
|
||
reg_mask[byte] |= 1 << (reg % 8);
|
||
}
|
||
}
|
||
|
||
/* Check that all the targets are on boundaries. */
|
||
for (i = 0; i < ax->len; i++)
|
||
if (targets[i] && !boundary[i])
|
||
{
|
||
reqs->flaw = agent_flaw_bad_jump;
|
||
free (reg_mask);
|
||
return;
|
||
}
|
||
|
||
reqs->final_height = height;
|
||
reqs->reg_mask_len = reg_mask_len;
|
||
reqs->reg_mask = reg_mask;
|
||
}
|