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x86: change fetch error handling in get_valid_dis386()

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Introduce a special error indicator node, for the sole (real) caller
to recognize and act upon.
This commit is contained in:
Jan Beulich 2023-04-21 12:08:45 +02:00
parent bf4d07d539
commit 0b51ac4277
1 changed files with 26 additions and 30 deletions
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56
opcodes/i386-dis.c
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@ -9196,6 +9196,9 @@ with the -M switch (multiple options should be separated by commas):\n"));
/* Bad opcode. */
static const struct dis386 bad_opcode = { "(bad)", { XX }, 0 };
/* Fetch error indicator. */
static const struct dis386 err_opcode = { NULL, { XX }, 0 };
/* Get a pointer to struct dis386 with a valid name. */
static const struct dis386 *
@ -9297,13 +9300,13 @@ get_valid_dis386 (const struct dis386 *dp, instr_info *ins)
break;
case USE_3BYTE_TABLE:
FETCH_DATA (ins->info, ins->codep + 2);
if (!fetch_code (ins->info, ins->codep + 2))
return &err_opcode;
vindex = *ins->codep++;
dp = &three_byte_table[dp->op[1].bytemode][vindex];
ins->end_codep = ins->codep;
ins->modrm.mod = (*ins->codep >> 6) & 3;
ins->modrm.reg = (*ins->codep >> 3) & 7;
ins->modrm.rm = *ins->codep & 7;
if (!fetch_modrm (ins))
return &err_opcode;
break;
case USE_VEX_LEN_TABLE:
@ -9357,7 +9360,8 @@ get_valid_dis386 (const struct dis386 *dp, instr_info *ins)
break;
case USE_XOP_8F_TABLE:
FETCH_DATA (ins->info, ins->codep + 3);
if (!fetch_code (ins->info, ins->codep + 3))
return &err_opcode;
ins->rex = ~(*ins->codep >> 5) & 0x7;
/* VEX_TABLE_INDEX is the mmmmm part of the XOP byte 1 "RCB.mmmmm". */
@ -9409,10 +9413,8 @@ get_valid_dis386 (const struct dis386 *dp, instr_info *ins)
dp = &xop_table[vex_table_index][vindex];
ins->end_codep = ins->codep;
FETCH_DATA (ins->info, ins->codep + 1);
ins->modrm.mod = (*ins->codep >> 6) & 3;
ins->modrm.reg = (*ins->codep >> 3) & 7;
ins->modrm.rm = *ins->codep & 7;
if (!fetch_modrm (ins))
return &err_opcode;
/* No XOP encoding so far allows for a non-zero embedded prefix. Avoid
having to decode the bits for every otherwise valid encoding. */
@ -9422,7 +9424,8 @@ get_valid_dis386 (const struct dis386 *dp, instr_info *ins)
case USE_VEX_C4_TABLE:
/* VEX prefix. */
FETCH_DATA (ins->info, ins->codep + 3);
if (!fetch_code (ins->info, ins->codep + 3))
return &err_opcode;
ins->rex = ~(*ins->codep >> 5) & 0x7;
switch ((*ins->codep & 0x1f))
{
@ -9475,18 +9478,15 @@ get_valid_dis386 (const struct dis386 *dp, instr_info *ins)
dp = &vex_table[vex_table_index][vindex];
ins->end_codep = ins->codep;
/* There is no MODRM byte for VEX0F 77. */
if (vex_table_index != VEX_0F || vindex != 0x77)
{
FETCH_DATA (ins->info, ins->codep + 1);
ins->modrm.mod = (*ins->codep >> 6) & 3;
ins->modrm.reg = (*ins->codep >> 3) & 7;
ins->modrm.rm = *ins->codep & 7;
}
if ((vex_table_index != VEX_0F || vindex != 0x77)
&& !fetch_modrm (ins))
return &err_opcode;
break;
case USE_VEX_C5_TABLE:
/* VEX prefix. */
FETCH_DATA (ins->info, ins->codep + 2);
if (!fetch_code (ins->info, ins->codep + 2))
return &err_opcode;
ins->rex = (*ins->codep & 0x80) ? 0 : REX_R;
/* For the 2-byte VEX prefix in 32-bit mode, the highest bit in
@ -9513,13 +9513,8 @@ get_valid_dis386 (const struct dis386 *dp, instr_info *ins)
dp = &vex_table[dp->op[1].bytemode][vindex];
ins->end_codep = ins->codep;
/* There is no MODRM byte for VEX 77. */
if (vindex != 0x77)
{
FETCH_DATA (ins->info, ins->codep + 1);
ins->modrm.mod = (*ins->codep >> 6) & 3;
ins->modrm.reg = (*ins->codep >> 3) & 7;
ins->modrm.rm = *ins->codep & 7;
}
if (vindex != 0x77 && !fetch_modrm (ins))
return &err_opcode;
break;
case USE_VEX_W_TABLE:
@ -9533,7 +9528,8 @@ get_valid_dis386 (const struct dis386 *dp, instr_info *ins)
ins->two_source_ops = false;
/* EVEX prefix. */
ins->vex.evex = true;
FETCH_DATA (ins->info, ins->codep + 4);
if (!fetch_code (ins->info, ins->codep + 4))
return &err_opcode;
/* The first byte after 0x62. */
ins->rex = ~(*ins->codep >> 5) & 0x7;
ins->vex.r = *ins->codep & 0x10;
@ -9608,10 +9604,8 @@ get_valid_dis386 (const struct dis386 *dp, instr_info *ins)
vindex = *ins->codep++;
dp = &evex_table[vex_table_index][vindex];
ins->end_codep = ins->codep;
FETCH_DATA (ins->info, ins->codep + 1);
ins->modrm.mod = (*ins->codep >> 6) & 3;
ins->modrm.reg = (*ins->codep >> 3) & 7;
ins->modrm.rm = *ins->codep & 7;
if (!fetch_modrm (ins))
return &err_opcode;
/* Set vector length. */
if (ins->modrm.mod == 3 && ins->vex.b)
@ -9998,6 +9992,8 @@ print_insn (bfd_vma pc, disassemble_info *info, int intel_syntax)
else
{
dp = get_valid_dis386 (dp, &ins);
if (dp == &err_opcode)
return fetch_error (&ins);
if (dp != NULL && putop (&ins, dp->name, sizeflag) == 0)
{
if (!get_sib (&ins, sizeflag))