yggdrasil/binutils-gdb
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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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opcodes/i386-dis.c
+17 -16
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@@ -161,9 +161,9 @@ struct instr_info
char *obufp; char *obufp;
char *mnemonicendp; char *mnemonicendp;
const uint8_t *start_codep; const uint8_t *start_codep;
uint8_t *insn_codep;
uint8_t *codep; uint8_t *codep;
const uint8_t *end_codep; const uint8_t *end_codep;
unsigned char nr_prefixes;
signed char last_lock_prefix; signed char last_lock_prefix;
signed char last_repz_prefix; signed char last_repz_prefix;
signed char last_repnz_prefix; signed char last_repnz_prefix;
@@ -247,8 +247,8 @@ struct dis_private {
bfd_vma insn_start; bfd_vma insn_start;
int orig_sizeflag; int orig_sizeflag;
/* Points to first byte not fetched. */ /* Indexes first byte not fetched. */
uint8_t *max_fetched; unsigned int fetched;
uint8_t the_buffer[2 * MAX_CODE_LENGTH - 1]; 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 to ADDR (exclusive) are valid. Returns true for success, false
on error. */ on error. */
static bool static bool
fetch_code (struct disassemble_info *info, uint8_t *until) fetch_code (struct disassemble_info *info, const uint8_t *until)
{ {
int status = -1; int status = -1;
struct dis_private *priv = info->private_data; 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; return true;
if (until <= priv->the_buffer + ARRAY_SIZE (priv->the_buffer)) if (priv->fetched + needed <= ARRAY_SIZE (priv->the_buffer))
status = (*info->read_memory_func) (start, status = (*info->read_memory_func) (start, fetch_end, needed, info);
priv->max_fetched,
until - priv->max_fetched,
info);
if (status != 0) if (status != 0)
{ {
/* If we did manage to read at least one byte, then /* If we did manage to read at least one byte, then
print_insn_i386 will do something sensible. Otherwise, print print_insn_i386 will do something sensible. Otherwise, print
an error. We do that here because this is where we know an error. We do that here because this is where we know
STATUS. */ STATUS. */
if (priv->max_fetched == priv->the_buffer) if (!priv->fetched)
(*info->memory_error_func) (status, start, info); (*info->memory_error_func) (status, start, info);
return false; return false;
} }
priv->max_fetched = until; priv->fetched += needed;
return true; return true;
} }
@@ -9782,7 +9781,7 @@ print_insn (bfd_vma pc, disassemble_info *info, int intel_syntax)
info->bytes_per_line = 7; info->bytes_per_line = 7;
info->private_data = &priv; info->private_data = &priv;
priv.max_fetched = priv.the_buffer; priv.fetched = 0;
priv.insn_start = pc; priv.insn_start = pc;
for (i = 0; i < MAX_OPERANDS; ++i) 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; goto fetch_error_out;
} }
ins.insn_codep = ins.codep; ins.nr_prefixes = ins.codep - ins.start_codep;
if (!fetch_code (info, ins.codep + 1)) if (!fetch_code (info, ins.codep + 1))
{ {
@@ -11829,7 +11828,9 @@ static bool
BadOp (instr_info *ins) BadOp (instr_info *ins)
{ {
/* Throw away prefixes and 1st. opcode byte. */ /* 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)"); ins->obufp = stpcpy (ins->obufp, "(bad)");
return true; return true;
} }