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x86: convert two pointers to (indexing) integers

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This in particular reduces the number of pointers to non-const that we
have (and that could potentially be used for undue modification of
state). As a result, fetch_code()'s 2nd parameter can then also become
pointer-to-const.
This commit is contained in:
Jan Beulich 2023-05-26 09:53:51 +02:00
parent d8acf37693
commit 1a3b4f90bc
1 changed files with 17 additions and 16 deletions
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33
opcodes/i386-dis.c
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@ -161,9 +161,9 @@ struct instr_info
char *obufp;
char *mnemonicendp;
const uint8_t *start_codep;
uint8_t *insn_codep;
uint8_t *codep;
const uint8_t *end_codep;
unsigned char nr_prefixes;
signed char last_lock_prefix;
signed char last_repz_prefix;
signed char last_repnz_prefix;
@ -247,8 +247,8 @@ struct dis_private {
bfd_vma insn_start;
int orig_sizeflag;
/* Points to first byte not fetched. */
uint8_t *max_fetched;
/* Indexes first byte not fetched. */
unsigned int fetched;
uint8_t the_buffer[2 * MAX_CODE_LENGTH - 1];
};
@ -289,32 +289,31 @@ struct dis_private {
to ADDR (exclusive) are valid. Returns true for success, false
on error. */
static bool
fetch_code (struct disassemble_info *info, uint8_t *until)
fetch_code (struct disassemble_info *info, const uint8_t *until)
{
int status = -1;
struct dis_private *priv = info->private_data;
bfd_vma start = priv->insn_start + (priv->max_fetched - priv->the_buffer);
bfd_vma start = priv->insn_start + priv->fetched;
uint8_t *fetch_end = priv->the_buffer + priv->fetched;
ptrdiff_t needed = until - fetch_end;
if (until <= priv->max_fetched)
if (needed <= 0)
return true;
if (until <= priv->the_buffer + ARRAY_SIZE (priv->the_buffer))
status = (*info->read_memory_func) (start,
priv->max_fetched,
until - priv->max_fetched,
info);
if (priv->fetched + needed <= ARRAY_SIZE (priv->the_buffer))
status = (*info->read_memory_func) (start, fetch_end, needed, info);
if (status != 0)
{
/* If we did manage to read at least one byte, then
print_insn_i386 will do something sensible. Otherwise, print
an error. We do that here because this is where we know
STATUS. */
if (priv->max_fetched == priv->the_buffer)
if (!priv->fetched)
(*info->memory_error_func) (status, start, info);
return false;
}
priv->max_fetched = until;
priv->fetched += needed;
return true;
}
@ -9782,7 +9781,7 @@ print_insn (bfd_vma pc, disassemble_info *info, int intel_syntax)
info->bytes_per_line = 7;
info->private_data = &priv;
priv.max_fetched = priv.the_buffer;
priv.fetched = 0;
priv.insn_start = pc;
for (i = 0; i < MAX_OPERANDS; ++i)
@ -9814,7 +9813,7 @@ print_insn (bfd_vma pc, disassemble_info *info, int intel_syntax)
goto fetch_error_out;
}
ins.insn_codep = ins.codep;
ins.nr_prefixes = ins.codep - ins.start_codep;
if (!fetch_code (info, ins.codep + 1))
{
@ -11829,7 +11828,9 @@ static bool
BadOp (instr_info *ins)
{
/* Throw away prefixes and 1st. opcode byte. */
ins->codep = ins->insn_codep + 1;
struct dis_private *priv = ins->info->private_data;
ins->codep = priv->the_buffer + ins->nr_prefixes + 1;
ins->obufp = stpcpy (ins->obufp, "(bad)");
return true;
}