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BR 2496848: Tighten ea checks

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Check if the offset and the representation are equivalent.

Disallow REL on absolute addresses.
I'm not sure what that would mean and the output formats don't support it.

Warn about ignored displacement size modifiers.
This commit is contained in:
Victor van den Elzen 2010-01-24 21:24:57 +01:00
parent defdaebcbb
commit 0d268fb78c
3 changed files with 79 additions and 5 deletions
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32
assemble.c
View file

@ -254,7 +254,7 @@ static void warn_overflow_const(int64_t data, int size)
static void warn_overflow_opd(const struct operand *o, int size)
{
if (size < 8 && o->wrt == NO_SEG && o->segment == NO_SEG) {
if (o->wrt == NO_SEG && o->segment == NO_SEG) {
if (overflow_general(o->offset, size))
warn_overflow(ERR_PASS2, size);
}
@ -722,7 +722,7 @@ int64_t insn_size(int32_t segment, int64_t offset, int bits, uint32_t cp,
int64_t isize;
const uint8_t *codes = temp->code;
int j;
isize = calcsize(segment, offset, bits, instruction, codes);
if (isize < 0)
return -1;
@ -1858,18 +1858,25 @@ static void gencode(int32_t segment, int64_t offset, int bits,
case 4:
case 8:
data = opy->offset;
warn_overflow_opd(opy, ea_data.bytes);
s += ea_data.bytes;
if (ea_data.rip) {
if (opy->segment == segment) {
data -= insn_end;
if (overflow_signed(data, ea_data.bytes))
warn_overflow(ERR_PASS2, ea_data.bytes);
out(offset, segment, &data, OUT_ADDRESS,
ea_data.bytes, NO_SEG, NO_SEG);
} else {
/* overflow check in output/linker? */
out(offset, segment, &data, OUT_REL4ADR,
insn_end - offset, opy->segment, opy->wrt);
}
} else {
if (overflow_general(opy->offset, ins->addr_size >> 3) ||
signed_bits(opy->offset, ins->addr_size) !=
signed_bits(opy->offset, ea_data.bytes * 8))
warn_overflow(ERR_PASS2, ea_data.bytes);
type = OUT_ADDRESS;
out(offset, segment, &data, OUT_ADDRESS,
ea_data.bytes, opy->segment, opy->wrt);
@ -2232,6 +2239,20 @@ static ea *process_ea(operand * input, ea * output, int bits,
if (input->basereg == -1
&& (input->indexreg == -1 || input->scale == 0)) {
/* it's a pure offset */
if (bits == 64 && ((input->type & IP_REL) == IP_REL) &&
input->segment == NO_SEG) {
nasm_error(ERR_WARNING | ERR_PASS1, "absolute address can not be RIP-relative");
input->type &= ~IP_REL;
input->type |= MEMORY;
}
if (input->eaflags & EAF_BYTEOFFS ||
(input->eaflags & EAF_WORDOFFS &&
input->disp_size != (addrbits != 16 ? 32 : 16))) {
nasm_error(ERR_WARNING | ERR_PASS1, "displacement size ignored on absolute address");
}
if (bits == 64 && (~input->type & IP_REL)) {
int scale, index, base;
output->sib_present = true;
@ -2250,7 +2271,7 @@ static ea *process_ea(operand * input, ea * output, int bits,
}
} else { /* it's an indirection */
int i = input->indexreg, b = input->basereg, s = input->scale;
int32_t o = input->offset, seg = input->segment;
int32_t seg = input->segment;
int hb = input->hintbase, ht = input->hinttype;
int t, it, bt; /* register numbers */
opflags_t x, ix, bx; /* register flags */
@ -2278,7 +2299,7 @@ static ea *process_ea(operand * input, ea * output, int bits,
if ((ix|bx) & (BITS32|BITS64)) {
/* it must be a 32/64-bit memory reference. Firstly we have
* to check that all registers involved are type E/Rxx. */
int32_t sok = BITS32|BITS64;
int32_t sok = BITS32|BITS64, o = input->offset;
if (it != -1) {
if (!(REG64 & ~ix) || !(REG32 & ~ix))
@ -2417,6 +2438,7 @@ static ea *process_ea(operand * input, ea * output, int bits,
}
} else { /* it's 16-bit */
int mod, rm;
int16_t o = input->offset;
/* check for 64-bit long mode */
if (addrbits == 64)

10
nasmlib.h
View file

@ -445,6 +445,16 @@ static inline bool overflow_unsigned(int64_t value, int bytes)
return value < vmin || value > vmax;
}
static inline int64_t signed_bits(int64_t value, int bits)
{
if (bits < 64) {
value &= ((int64_t)1 << bits) - 1;
if (value & (int64_t)1 << (bits - 1))
value |= (int64_t)-1 << bits;
}
return value;
}
int idata_bytes(int opcode);
/* check if value is power of 2 */

42
test/br2496848.asm Normal file
View file

@ -0,0 +1,42 @@
;Testname=unoptimized; Arguments=-O0 -fbin -o br2496848.bin; Files=stdout stderr br2496848.bin
;Testname=optimized; Arguments=-Ox -fbin -o br2496848.bin; Files=stdout stderr br2496848.bin
bits 64
foo:
default abs
mov al, [qword 0xffffffffffffffff]
mov al, [qword 0x1ffffffffffffffff]
mov cl, [byte 0x12345678]
default rel
mov cl, [foo]
mov cl, [foo + 0x10000000]
mov cl, [foo + 0x100000000]
mov cl, [0x100]
mov cl, [$$ + 0x100]
mov cl, [rax - 1]
mov cl, [rax + 0xffffffff]
mov cl, [rax + 0x1ffffffff]
bits 32
mov cl, [eax - 1]
mov cl, [eax + 0xffffffff]
mov cl, [eax + 0x1ffffffff]
mov cl, [byte eax + 0xffffffff]
mov cl, [byte eax + 0x1ffffffff]
mov cl, [byte eax + 0x1000ffff]
bits 16
mov cl, [di - 1]
mov cl, [di + 0xffff]
mov cl, [di + 0x1ffff]
mov cl, [byte di + 0xffff]
mov cl, [byte di + 0x1ffff]
mov cl, [byte di + 0x10ff]