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Remove the --allow-64-bits option and make it a warning

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Remove the --allow-64-bits relocation, and instead make it a
suppressible warning in the case of a zero-extended relocation, and an
error in the case of a sign-extended relocation.

Relocations which can be losslessly represented in the output format
do not issue any diagnostic at all, as there is no problem in that
case.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
This commit is contained in:
H. Peter Anvin 2016-02-08 10:32:13 -08:00
parent 0c11e123b2
commit d24dd5fecc
5 changed files with 29 additions and 29 deletions
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29
assemble.c
View File

@ -1,6 +1,6 @@
/* ----------------------------------------------------------------------- *
*
* Copyright 1996-2014 The NASM Authors - All Rights Reserved
* Copyright 1996-2016 The NASM Authors - All Rights Reserved
* See the file AUTHORS included with the NASM distribution for
* the specific copyright holders.
*
@ -308,7 +308,8 @@ static void warn_overflow_opd(const struct operand *o, int size)
/*
* This routine wrappers the real output format's output routine,
* in order to pass a copy of the data off to the listing file
* generator at the same time.
* generator at the same time, flatten unnecessary relocations,
* and verify backend compatibility.
*/
static void out(int64_t offset, int32_t segto, const void *data,
enum out_type type, uint64_t size,
@ -317,6 +318,9 @@ static void out(int64_t offset, int32_t segto, const void *data,
static int32_t lineno = 0; /* static!!! */
static char *lnfname = NULL;
uint8_t p[8];
const int asize = abs((int)size); /* True address size */
const int abits = asize << 3; /* Address size in bits */
const int amax = maxbits >> 3; /* Maximum address size in bytes */
if (type == OUT_ADDRESS && segment == NO_SEG && wrt == NO_SEG) {
/*
@ -325,13 +329,12 @@ static void out(int64_t offset, int32_t segto, const void *data,
*/
uint8_t *q = p;
size = abs((int)size);
if (size > 8) {
if (asize > 8) {
errfunc(ERR_PANIC, "OUT_ADDRESS with size > 8");
return;
}
WRITEADDR(q, *(int64_t *)data, size);
WRITEADDR(q, *(int64_t *)data, asize);
data = p;
type = OUT_RAWDATA;
}
@ -350,6 +353,22 @@ static void out(int64_t offset, int32_t segto, const void *data,
if (src_get(&lineno, &lnfname))
outfmt->current_dfmt->linenum(lnfname, lineno, segto);
if (type == OUT_ADDRESS && abits > maxbits) {
if (asize < 0) {
errfunc(ERR_NONFATAL,
"%d-bit signed relocation unsupported by output format %s\n",
abits, outfmt->shortname);
} else {
errfunc(ERR_WARNING | ERR_WARN_ZEXTRELOC,
"%d-bit unsigned relocation zeroq-padded from %d bits\n",
abits, maxbits);
outfmt->output(segto, data, type, amax, segment, wrt);
size -= amax;
}
data = zero_buffer;
type = OUT_RAWDATA;
}
outfmt->output(segto, data, type, size, segment, wrt);
}

10
doc/nasmdoc.src
View File

@ -1010,16 +1010,6 @@ underscore to all global and external variables, as C requires it in
some, but not all, system calling conventions.
\S{opt-allow64bit} The \i\c{--allow-64-bit} Option.
The \c{--allow-64-bit} option allows using 64-bit instructions in a
32-bit or 16-bit output format. This is useful in a few situations,
such as when writing code switching from 32-bit to 64-bit mode and
linking into a 32-bit module. However, it is important to be aware of
the restriction the output format poses on you in terms of
relocations. Use with caution!
\S{nasmenv} The \i\c{NASMENV} \i{Environment} Variable
If you define an environment variable called \c{NASMENV}, the program

14
nasm.c
View File

@ -88,7 +88,6 @@ static int using_debug_info, opt_verbose_info;
bool tasm_compatible_mode = false;
int pass0, passn;
int maxbits = 0;
static bool allow_64_bit = false;
int globalrel = 0;
int globalbnd = 0;
@ -169,6 +168,7 @@ static const struct warning {
{"lock", "lock prefix on unlockable instructions", true},
{"hle", "invalid hle prefixes", true},
{"bnd", "invalid bnd prefixes", true},
{"zero-reloc", "relocation zero-extended to match output format", true},
};
static bool want_usage;
@ -618,12 +618,10 @@ struct textargs {
enum text_options {
OPT_PREFIX,
OPT_POSTFIX,
OPT_ALLOW_64_BIT
};
struct textargs textopts[] = {
{"prefix", OPT_PREFIX},
{"postfix", OPT_POSTFIX},
{"allow-64-bit", OPT_ALLOW_64_BIT},
{NULL, 0}
};
@ -981,9 +979,7 @@ set_warning:
}
break;
}
case OPT_ALLOW_64_BIT:
allow_64_bit = true;
break;
default:
{
nasm_error(ERR_NONFATAL | ERR_NOFILE | ERR_USAGE,
@ -2101,12 +2097,6 @@ static int get_bits(char *value)
"cannot specify 64-bit segment on processor below an x86-64");
i = 16;
}
if (i != maxbits && !allow_64_bit) {
nasm_error(ERR_NONFATAL,
"%s output format does not support 64-bit code",
ofmt->shortname);
i = 16;
}
} else {
nasm_error(pass0 < 2 ? ERR_NONFATAL : ERR_FATAL,
"`%s' is not a valid segment size; must be 16, 32 or 64",

2
nasm.h
View File

@ -1,6 +1,6 @@
/* ----------------------------------------------------------------------- *
*
* Copyright 1996-2014 The NASM Authors - All Rights Reserved
* Copyright 1996-2016 The NASM Authors - All Rights Reserved
* See the file AUTHORS included with the NASM distribution for
* the specific copyright holders.
*

3
nasmlib.h
View File

@ -125,7 +125,8 @@ no_return nasm_panic_from_macro(const char *file, int line);
#define ERR_WARN_LOCK WARN(12) /* bad LOCK prefixes */
#define ERR_WARN_HLE WARN(13) /* bad HLE prefixes */
#define ERR_WARN_BND WARN(14) /* bad BND prefixes */
#define ERR_WARN_MAX 14 /* the highest numbered one */
#define ERR_WARN_ZEXTRELOC WARN(15) /* relocation zero-extended */
#define ERR_WARN_MAX 15 /* the highest numbered one */
/*
* Wrappers around malloc, realloc and free. nasm_malloc will