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892c4818ce
nasm/asm/directiv.c
H. Peter Anvin 892c4818ce Add support for backend-defined subsections and label hacks 
MachO has this odd thing called "subsections via symbols", by which a
symbol can magically start what effectively is a new section. To
support this, add support for a calldown into the backend when a new
symbol is defined *at the current output location*, and allow it to
switch the current segment.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2018-05-30 14:48:18 -07:00

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/* ----------------------------------------------------------------------- *
*
* Copyright 1996-2018 The NASM Authors - All Rights Reserved
* See the file AUTHORS included with the NASM distribution for
* the specific copyright holders.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following
* conditions are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided
* with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* ----------------------------------------------------------------------- */
/*
* Parse and handle assembler directives
*/
#include "compiler.h"
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <limits.h>
#include "nasm.h"
#include "nasmlib.h"
#include "ilog2.h"
#include "error.h"
#include "float.h"
#include "stdscan.h"
#include "preproc.h"
#include "eval.h"
#include "assemble.h"
#include "outform.h"
#include "listing.h"
#include "labels.h"
#include "iflag.h"
struct cpunames {
const char *name;
unsigned int level;
/* Eventually a table of features */
};
static iflag_t get_cpu(const char *value)
{
iflag_t r;
const struct cpunames *cpu;
static const struct cpunames cpunames[] = {
{ "8086", IF_8086 },
{ "186", IF_186 },
{ "286", IF_286 },
{ "386", IF_386 },
{ "486", IF_486 },
{ "586", IF_PENT },
{ "pentium", IF_PENT },
{ "pentiummmx", IF_PENT },
{ "686", IF_P6 },
{ "p6", IF_P6 },
{ "ppro", IF_P6 },
{ "pentiumpro", IF_P6 },
{ "p2", IF_P6 }, /* +MMX */
{ "pentiumii", IF_P6 },
{ "p3", IF_KATMAI },
{ "katmai", IF_KATMAI },
{ "p4", IF_WILLAMETTE },
{ "willamette", IF_WILLAMETTE },
{ "prescott", IF_PRESCOTT },
{ "x64", IF_X86_64 },
{ "x86-64", IF_X86_64 },
{ "ia64", IF_IA64 },
{ "ia-64", IF_IA64 },
{ "itanium", IF_IA64 },
{ "itanic", IF_IA64 },
{ "merced", IF_IA64 },
{ "any", IF_PLEVEL },
{ "default", IF_PLEVEL },
{ "all", IF_PLEVEL },
{ NULL, IF_PLEVEL } /* Error and final default entry */
};
iflag_clear_all(&r);
for (cpu = cpunames; cpu->name; cpu++) {
if (!strcmp(value, cpu->name))
break;
}
if (!cpu->name) {
nasm_error(pass0 < 2 ? ERR_NONFATAL : ERR_FATAL,
"unknown 'cpu' type '%s'", value);
}
iflag_set_cpu(&r, cpu->level);
return r;
}
static int get_bits(const char *value)
{
int i = atoi(value);
switch (i) {
case 16:
break; /* Always safe */
case 32:
if (!iflag_cpu_level_ok(&cpu, IF_386)) {
nasm_error(ERR_NONFATAL,
"cannot specify 32-bit segment on processor below a 386");
i = 16;
}
break;
case 64:
if (!iflag_cpu_level_ok(&cpu, IF_X86_64)) {
nasm_error(ERR_NONFATAL,
"cannot specify 64-bit segment on processor below an x86-64");
i = 16;
}
break;
default:
nasm_error(pass0 < 2 ? ERR_NONFATAL : ERR_FATAL,
"`%s' is not a valid segment size; must be 16, 32 or 64",
value);
i = 16;
break;
}
return i;
}
static enum directive parse_directive_line(char **directive, char **value)
{
char *p, *q, *buf;
buf = nasm_skip_spaces(*directive);
/*
* It should be enclosed in [ ].
* XXX: we don't check there is nothing else on the remainder of the
* line, except a possible comment.
*/
if (*buf != '[')
return D_none;
q = strchr(buf, ']');
if (!q)
return D_corrupt;
/*
* Strip off the comments. XXX: this doesn't account for quoted
* strings inside a directive. We should really strip the
* comments in generic code, not here. While we're at it, it
* would be better to pass the backend a series of tokens instead
* of a raw string, and actually process quoted strings for it,
* like of like argv is handled in C.
*/
p = strchr(buf, ';');
if (p) {
if (p < q) /* ouch! somewhere inside */
return D_corrupt;
*p = '\0';
}
/* no brace, no trailing spaces */
*q = '\0';
nasm_zap_spaces_rev(--q);
/* directive */
p = nasm_skip_spaces(++buf);
q = nasm_skip_word(p);
if (!q)
return D_corrupt; /* sigh... no value there */
*q = '\0';
*directive = p;
/* and value finally */
p = nasm_skip_spaces(++q);
*value = p;
return directive_find(*directive);
}
/*
* Process a line from the assembler and try to handle it if it
* is a directive. Return true if the line was handled (including
* if it was an error), false otherwise.
*/
bool process_directives(char *directive)
{
enum directive d;
char *value, *p, *q, *special;
struct tokenval tokval;
bool bad_param = false;
int pass2 = passn > 1 ? 2 : 1;
d = parse_directive_line(&directive, &value);
switch (d) {
case D_none:
return D_none; /* Not a directive */
case D_corrupt:
nasm_error(ERR_NONFATAL, "invalid directive line");
break;
default: /* It's a backend-specific directive */
switch (ofmt->directive(d, value, pass2)) {
case DIRR_UNKNOWN:
goto unknown;
case DIRR_OK:
case DIRR_ERROR:
break;
case DIRR_BADPARAM:
bad_param = true;
break;
default:
panic();
}
break;
case D_unknown:
unknown:
nasm_error(pass0 < 2 ? ERR_NONFATAL : ERR_PANIC,
"unrecognised directive [%s]", directive);
break;
case D_SEGMENT: /* [SEGMENT n] */
case D_SECTION:
{
int sb = globalbits;
int32_t seg = ofmt->section(value, pass2, &sb);
if (seg == NO_SEG) {
nasm_error(pass0 < 2 ? ERR_NONFATAL : ERR_PANIC,
"segment name `%s' not recognized", value);
} else {
globalbits = sb;
switch_segment(seg);
}
break;
}
case D_SECTALIGN: /* [SECTALIGN n] */
{
expr *e;
if (*value) {
stdscan_reset();
stdscan_set(value);
tokval.t_type = TOKEN_INVALID;
e = evaluate(stdscan, NULL, &tokval, NULL, pass2, NULL);
if (e) {
uint64_t align = e->value;
if (!is_power2(e->value)) {
nasm_error(ERR_NONFATAL,
"segment alignment `%s' is not power of two",
value);
} else if (align > UINT64_C(0x7fffffff)) {
/*
* FIXME: Please make some sane message here
* ofmt should have some 'check' method which
* would report segment alignment bounds.
*/
nasm_error(ERR_NONFATAL,
"absurdly large segment alignment `%s' (2^%d)",
value, ilog2_64(align));
}
/* callee should be able to handle all details */
if (location.segment != NO_SEG)
ofmt->sectalign(location.segment, align);
}
}
break;
}
case D_EXTERN: /* [EXTERN label:special] */
if (*value == '$')
value++; /* skip initial $ if present */
if (pass0 == 2) {
q = value;
while (*q && *q != ':')
q++;
if (*q == ':') {
*q++ = '\0';
ofmt->symdef(value, 0L, 0L, 3, q);
}
} else if (passn == 1) {
bool validid = true;
q = value;
if (!isidstart(*q))
validid = false;
while (*q && *q != ':') {
if (!isidchar(*q))
validid = false;
q++;
}
if (!validid) {
nasm_error(ERR_NONFATAL, "identifier expected after EXTERN");
break;
}
if (*q == ':') {
*q++ = '\0';
special = q;
} else
special = NULL;
if (!is_extern(value)) { /* allow re-EXTERN to be ignored */
int temp = pass0;
pass0 = 1; /* fake pass 1 in labels.c */
declare_as_global(value, special);
define_label(value, seg_alloc(), 0L, NULL,
false, true);
pass0 = temp;
}
} /* else pass0 == 1 */
break;
case D_BITS: /* [BITS bits] */
globalbits = get_bits(value);
break;
case D_GLOBAL: /* [GLOBAL symbol:special] */
if (*value == '$')
value++; /* skip initial $ if present */
if (pass0 == 2) { /* pass 2 */
q = value;
while (*q && *q != ':')
q++;
if (*q == ':') {
*q++ = '\0';
ofmt->symdef(value, 0L, 0L, 3, q);
}
} else if (pass2 == 1) { /* pass == 1 */
bool validid = true;
q = value;
if (!isidstart(*q))
validid = false;
while (*q && *q != ':') {
if (!isidchar(*q))
validid = false;
q++;
}
if (!validid) {
nasm_error(ERR_NONFATAL,
"identifier expected after GLOBAL");
break;
}
if (*q == ':') {
*q++ = '\0';
special = q;
} else
special = NULL;
declare_as_global(value, special);
} /* pass == 1 */
break;
case D_COMMON: /* [COMMON symbol size:special] */
{
int64_t size;
bool rn_error;
bool validid;
if (*value == '$')
value++; /* skip initial $ if present */
p = value;
validid = true;
if (!isidstart(*p))
validid = false;
while (*p && !nasm_isspace(*p)) {
if (!isidchar(*p))
validid = false;
p++;
}
if (!validid) {
nasm_error(ERR_NONFATAL, "identifier expected after COMMON");
break;
}
if (*p) {
p = nasm_zap_spaces_fwd(p);
q = p;
while (*q && *q != ':')
q++;
if (*q == ':') {
*q++ = '\0';
special = q;
} else {
special = NULL;
}
size = readnum(p, &rn_error);
if (rn_error) {
nasm_error(ERR_NONFATAL,
"invalid size specified"
" in COMMON declaration");
break;
}
} else {
nasm_error(ERR_NONFATAL,
"no size specified in"
" COMMON declaration");
break;
}
if (pass0 < 2) {
define_common(value, seg_alloc(), size, special);
} else if (pass0 == 2) {
if (special)
ofmt->symdef(value, 0L, 0L, 3, special);
}
break;
}
case D_ABSOLUTE: /* [ABSOLUTE address] */
{
expr *e;
stdscan_reset();
stdscan_set(value);
tokval.t_type = TOKEN_INVALID;
e = evaluate(stdscan, NULL, &tokval, NULL, pass2, NULL);
if (e) {
if (!is_reloc(e))
nasm_error(pass0 ==
1 ? ERR_NONFATAL : ERR_PANIC,
"cannot use non-relocatable expression as "
"ABSOLUTE address");
else {
absolute.segment = reloc_seg(e);
absolute.offset = reloc_value(e);
}
} else if (passn == 1)
absolute.offset = 0x100; /* don't go near zero in case of / */
else
nasm_panic(0, "invalid ABSOLUTE address "
"in pass two");
in_absolute = true;
location.segment = NO_SEG;
break;
}
case D_DEBUG: /* [DEBUG] */
{
bool badid, overlong;
char debugid[128];
p = value;
q = debugid;
badid = overlong = false;
if (!isidstart(*p)) {
badid = true;
} else {
while (*p && !nasm_isspace(*p)) {
if (q >= debugid + sizeof debugid - 1) {
overlong = true;
break;
}
if (!isidchar(*p))
badid = true;
*q++ = *p++;
}
*q = 0;
}
if (badid) {
nasm_error(passn == 1 ? ERR_NONFATAL : ERR_PANIC,
"identifier expected after DEBUG");
break;
}
if (overlong) {
nasm_error(passn == 1 ? ERR_NONFATAL : ERR_PANIC,
"DEBUG identifier too long");
break;
}
p = nasm_skip_spaces(p);
if (pass0 == 2)
dfmt->debug_directive(debugid, p);
break;
}
case D_WARNING: /* [WARNING {+|-|*}warn-name] */
if (!set_warning_status(value)) {
nasm_error(ERR_WARNING|ERR_WARN_UNK_WARNING,
"unknown warning option: %s", value);
}
break;
case D_CPU: /* [CPU] */
cpu = get_cpu(value);
break;
case D_LIST: /* [LIST {+|-}] */
value = nasm_skip_spaces(value);
if (*value == '+') {
user_nolist = false;
} else {
if (*value == '-') {
user_nolist = true;
} else {
bad_param = true;
}
}
break;
case D_DEFAULT: /* [DEFAULT] */
stdscan_reset();
stdscan_set(value);
tokval.t_type = TOKEN_INVALID;
if (stdscan(NULL, &tokval) != TOKEN_INVALID) {
switch (tokval.t_integer) {
case S_REL:
globalrel = 1;
break;
case S_ABS:
globalrel = 0;
break;
case P_BND:
globalbnd = 1;
break;
case P_NOBND:
globalbnd = 0;
break;
default:
bad_param = true;
break;
}
} else {
bad_param = true;
}
break;
case D_FLOAT:
if (float_option(value)) {
nasm_error(pass0 < 2 ? ERR_NONFATAL : ERR_PANIC,
"unknown 'float' directive: %s", value);
}
break;
case D_PRAGMA:
process_pragma(value);
break;
}
/* A common error message */
if (bad_param) {
nasm_error(ERR_NONFATAL, "invalid parameter to [%s] directive",
directive);
}
return d != D_none;
}
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