/* ----------------------------------------------------------------------- *
*
* Copyright 1996-2017 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.
*
* ----------------------------------------------------------------------- */
/*
* labels.c label handling for the Netwide Assembler
*/
#include "compiler.h"
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include "nasm.h"
#include "nasmlib.h"
#include "error.h"
#include "hashtbl.h"
#include "labels.h"
/*
* A local label is one that begins with exactly one period. Things
* that begin with _two_ periods are NASM-specific things.
*
* If TASM compatibility is enabled, a local label can also begin with
* @@, so @@local is a TASM compatible local label. Note that we only
* check for the first @ symbol, although TASM requires both.
*/
#define islocal(l) \
(tasm_compatible_mode ? \
(((l)[0] == '.' || (l)[0] == '@') && (l)[1] != '.') : \
((l)[0] == '.' && (l)[1] != '.'))
#define islocalchar(c) \
(tasm_compatible_mode ? \
((c) == '.' || (c) == '@') : \
((c) == '.'))
#define LABEL_BLOCK 128 /* no. of labels/block */
#define LBLK_SIZE (LABEL_BLOCK * sizeof(union label))
#define END_LIST -3 /* don't clash with NO_SEG! */
#define END_BLOCK -2
#define BOGUS_VALUE -4
#define PERMTS_SIZE 16384 /* size of text blocks */
#if (PERMTS_SIZE < IDLEN_MAX)
#error "IPERMTS_SIZE must be greater than or equal to IDLEN_MAX"
#endif
/* values for label.defn.is_global */
#define DEFINED_BIT 1
#define GLOBAL_BIT 2
#define EXTERN_BIT 4
#define COMMON_BIT 8
#define NOT_DEFINED_YET 0
#define TYPE_MASK 3
#define LOCAL_SYMBOL (DEFINED_BIT)
#define GLOBAL_PLACEHOLDER (GLOBAL_BIT)
#define GLOBAL_SYMBOL (DEFINED_BIT | GLOBAL_BIT)
union label { /* actual label structures */
struct {
int32_t segment;
int64_t offset;
char *label, *special;
int is_global, is_norm;
} defn;
struct {
int32_t movingon;
int64_t dummy;
union label *next;
} admin;
};
struct permts { /* permanent text storage */
struct permts *next; /* for the linked list */
int size, usage; /* size and used space in ... */
char data[PERMTS_SIZE]; /* ... the data block itself */
};
uint64_t global_offset_changed; /* counter for global offset changes */
static struct hash_table ltab; /* labels hash table */
static union label *ldata; /* all label data blocks */
static union label *lfree; /* labels free block */
static struct permts *perm_head; /* start of perm. text storage */
static struct permts *perm_tail; /* end of perm. text storage */
static void init_block(union label *blk);
static char *perm_copy(const char *string);
static char *prevlabel;
static bool initialized = false;
char lprefix[PREFIX_MAX] = { 0 };
char lpostfix[PREFIX_MAX] = { 0 };
/*
* Emit a symdef to the output and the debug format backends.
*/
static void out_symdef(char *name, int32_t segment, int64_t offset,
int is_global, char *special)
{
ofmt->symdef(name, segment, offset, is_global, special);
/*
* NASM special symbols are not passed to the debug format; none
* of the current backends want to see them.
*/
if (!(name[0] == '.' && name[1] == '.' && name[2] != '@'))
dfmt->debug_deflabel(name, segment, offset, is_global, special);
}
/*
* Internal routine: finds the `union label' corresponding to the
* given label name. Creates a new one, if it isn't found, and if
* `create' is true.
*/
static union label *find_label(const char *label, int create, int *created)
{
char *prev;
int prevlen, len;
union label *lptr, **lpp;
char label_str[IDLEN_MAX];
struct hash_insert ip;
if (islocal(label)) {
prev = prevlabel;
prevlen = strlen(prev);
len = strlen(label);
if (prevlen + len >= IDLEN_MAX) {
nasm_error(ERR_NONFATAL, "identifier length exceed %i bytes",
IDLEN_MAX);
return NULL;
}
memcpy(label_str, prev, prevlen);
memcpy(label_str+prevlen, label, len+1);
label = label_str;
} else {
prev = "";
prevlen = 0;
}
lpp = (union label **) hash_find(<ab, label, &ip);
lptr = lpp ? *lpp : NULL;
if (lptr || !create) {
if (created)
*created = 0;
return lptr;
}
/* Create a new label... */
if (lfree->admin.movingon == END_BLOCK) {
/*
* must allocate a new block
*/
lfree->admin.next = nasm_malloc(LBLK_SIZE);
lfree = lfree->admin.next;
init_block(lfree);
}
if (created)
*created = 1;
lfree->admin.movingon = BOGUS_VALUE;
lfree->defn.label = perm_copy(label);
lfree->defn.special = NULL;
lfree->defn.is_global = NOT_DEFINED_YET;
hash_add(&ip, lfree->defn.label, lfree);
return lfree++;
}
bool lookup_label(const char *label, int32_t *segment, int64_t *offset)
{
union label *lptr;
if (!initialized)
return false;
lptr = find_label(label, 0, NULL);
if (lptr && (lptr->defn.is_global & DEFINED_BIT)) {
*segment = lptr->defn.segment;
*offset = lptr->defn.offset;
return true;
}
return false;
}
bool is_extern(const char *label)
{
union label *lptr;
if (!initialized)
return false;
lptr = find_label(label, 0, NULL);
return (lptr && (lptr->defn.is_global & EXTERN_BIT));
}
void redefine_label(char *label, int32_t segment, int64_t offset, char *special,
bool is_norm, bool isextrn)
{
union label *lptr;
int exi, created;
/* This routine possibly ought to check for phase errors. Most assemblers
* check for phase errors at this point. I don't know whether phase errors
* are even possible, nor whether they are checked somewhere else
*/
(void)special; /* Don't warn that this parameter is unused */
(void)is_norm; /* Don't warn that this parameter is unused */
(void)isextrn; /* Don't warn that this parameter is unused */
#ifdef DEBUG
#if DEBUG < 3
if (!strncmp(label, "debugdump", 9))
#endif
nasm_error(ERR_DEBUG, "redefine_label (%s, %"PRIx32", %"PRIx64", %s, %d, %d)",
label, segment, offset, special, is_norm, isextrn);
#endif
lptr = find_label(label, 1, &created);
if (!lptr)
nasm_panic(0, "can't find label `%s' on pass two", label);
if (created)
nasm_error(ERR_WARNING, "label `%s' defined on pass two", label);
if (!islocal(label)) {
if (!islocalchar(*label) && lptr->defn.is_norm)
prevlabel = lptr->defn.label;
}
if (lptr->defn.offset != offset)
global_offset_changed++;
lptr->defn.offset = offset;
lptr->defn.segment = segment;
if (pass0 == 1) {
exi = !!(lptr->defn.is_global & GLOBAL_BIT);
if (exi) {
char *xsymbol;
int slen;
slen = strlen(lprefix);
slen += strlen(lptr->defn.label);
slen += strlen(lpostfix);
slen++; /* room for that null char */
xsymbol = nasm_malloc(slen);
snprintf(xsymbol, slen, "%s%s%s", lprefix, lptr->defn.label,
lpostfix);
out_symdef(xsymbol, segment, offset, exi,
special ? special : lptr->defn.special);
/** nasm_free(xsymbol); ! outobj.c stores the pointer; ouch!!! **/
} else {
if ((lptr->defn.is_global & (GLOBAL_BIT | EXTERN_BIT)) != EXTERN_BIT) {
out_symdef(lptr->defn.label, segment, offset, exi,
special ? special : lptr->defn.special);
}
}
} /* if (pass0 == 1) */
}
void define_label(char *label, int32_t segment, int64_t offset, char *special,
bool is_norm, bool isextrn)
{
union label *lptr;
int exi;
#ifdef DEBUG
#if DEBUG<3
if (!strncmp(label, "debugdump", 9))
#endif
nasm_error(ERR_DEBUG, "define_label (%s, %"PRIx32", %"PRIx64", %s, %d, %d)",
label, segment, offset, special, is_norm, isextrn);
#endif
lptr = find_label(label, 1, NULL);
if (!lptr)
return;
if (lptr->defn.is_global & DEFINED_BIT) {
nasm_error(ERR_NONFATAL, "symbol `%s' redefined", label);
return;
}
lptr->defn.is_global |= DEFINED_BIT;
if (isextrn)
lptr->defn.is_global |= EXTERN_BIT;
if (!islocalchar(label[0]) && is_norm) {
/* not local, but not special either */
prevlabel = lptr->defn.label;
} else if (islocal(label) && !*prevlabel) {
nasm_error(ERR_NONFATAL, "attempt to define a local label before any"
" non-local labels");
}
lptr->defn.segment = segment;
lptr->defn.offset = offset;
lptr->defn.is_norm = (!islocalchar(label[0]) && is_norm);
if (pass0 == 1 || (!is_norm && !isextrn && (segment > 0) && (segment & 1))) {
exi = !!(lptr->defn.is_global & GLOBAL_BIT);
if (exi) {
char *xsymbol;
int slen;
slen = strlen(lprefix);
slen += strlen(lptr->defn.label);
slen += strlen(lpostfix);
slen++; /* room for that null char */
xsymbol = nasm_malloc(slen);
snprintf(xsymbol, slen, "%s%s%s", lprefix, lptr->defn.label,
lpostfix);
out_symdef(xsymbol, segment, offset, exi,
special ? special : lptr->defn.special);
/** nasm_free(xsymbol); ! outobj.c stores the pointer; ouch!!! **/
} else {
if ((lptr->defn.is_global & (GLOBAL_BIT | EXTERN_BIT)) != EXTERN_BIT) {
out_symdef(lptr->defn.label, segment, offset, exi,
special ? special : lptr->defn.special);
}
}
} /* if (pass0 == 1) */
}
void define_common(char *label, int32_t segment, int32_t size, char *special)
{
union label *lptr;
lptr = find_label(label, 1, NULL);
if (!lptr)
return;
if ((lptr->defn.is_global & DEFINED_BIT) &&
(passn == 1 || !(lptr->defn.is_global & COMMON_BIT))) {
nasm_error(ERR_NONFATAL, "symbol `%s' redefined", label);
return;
}
lptr->defn.is_global |= DEFINED_BIT|COMMON_BIT;
if (!islocalchar(label[0])) {
prevlabel = lptr->defn.label;
} else {
nasm_error(ERR_NONFATAL, "attempt to define a local label as a "
"common variable");
return;
}
lptr->defn.segment = segment;
lptr->defn.offset = 0;
if (pass0 == 0)
return;
out_symdef(lptr->defn.label, segment, size, 2,
special ? special : lptr->defn.special);
}
void declare_as_global(char *label, char *special)
{
union label *lptr;
if (islocal(label)) {
nasm_error(ERR_NONFATAL, "attempt to declare local symbol `%s' as"
" global", label);
return;
}
lptr = find_label(label, 1, NULL);
if (!lptr)
return;
switch (lptr->defn.is_global & TYPE_MASK) {
case NOT_DEFINED_YET:
lptr->defn.is_global = GLOBAL_PLACEHOLDER;
lptr->defn.special = special ? perm_copy(special) : NULL;
break;
case GLOBAL_PLACEHOLDER: /* already done: silently ignore */
case GLOBAL_SYMBOL:
break;
case LOCAL_SYMBOL:
if (!(lptr->defn.is_global & EXTERN_BIT)) {
nasm_error(ERR_WARNING, "symbol `%s': GLOBAL directive "
"after symbol definition is an experimental feature", label);
lptr->defn.is_global = GLOBAL_SYMBOL;
}
break;
}
}
int init_labels(void)
{
hash_init(<ab, HASH_LARGE);
ldata = lfree = nasm_malloc(LBLK_SIZE);
init_block(lfree);
perm_head = perm_tail =
nasm_malloc(sizeof(struct permts));
perm_head->next = NULL;
perm_head->size = PERMTS_SIZE;
perm_head->usage = 0;
prevlabel = "";
initialized = true;
return 0;
}
void cleanup_labels(void)
{
union label *lptr, *lhold;
initialized = false;
hash_free(<ab);
lptr = lhold = ldata;
while (lptr) {
lptr = &lptr[LABEL_BLOCK-1];
lptr = lptr->admin.next;
nasm_free(lhold);
lhold = lptr;
}
while (perm_head) {
perm_tail = perm_head;
perm_head = perm_head->next;
nasm_free(perm_tail);
}
}
static void init_block(union label *blk)
{
int j;
for (j = 0; j < LABEL_BLOCK - 1; j++)
blk[j].admin.movingon = END_LIST;
blk[LABEL_BLOCK - 1].admin.movingon = END_BLOCK;
blk[LABEL_BLOCK - 1].admin.next = NULL;
}
static char *perm_copy(const char *string)
{
char *p;
int len = strlen(string)+1;
nasm_assert(len <= PERMTS_SIZE);
if (perm_tail->size - perm_tail->usage < len) {
perm_tail->next =
nasm_malloc(sizeof(struct permts));
perm_tail = perm_tail->next;
perm_tail->next = NULL;
perm_tail->size = PERMTS_SIZE;
perm_tail->usage = 0;
}
p = perm_tail->data + perm_tail->usage;
memcpy(p, string, len);
perm_tail->usage += len;
return p;
}
char *local_scope(char *label)
{
return islocal(label) ? prevlabel : "";
}
/*
* Notes regarding bug involving redefinition of external segments.
*
* Up to and including v0.97, the following code didn't work. From 0.97
* developers release 2 onwards, it will generate an error.
*
* EXTERN extlabel
* newlabel EQU extlabel + 1
*
* The results of allowing this code through are that two import records
* are generated, one for 'extlabel' and one for 'newlabel'.
*
* The reason for this is an inadequacy in the defined interface between
* the label manager and the output formats. The problem lies in how the
* output format driver tells that a label is an external label for which
* a label import record must be produced. Most (all except bin?) produce
* the record if the segment number of the label is not one of the internal
* segments that the output driver is producing.
*
* A simple fix to this would be to make the output formats keep track of
* which symbols they've produced import records for, and make them not
* produce import records for segments that are already defined.
*
* The best way, which is slightly harder but reduces duplication of code
* and should therefore make the entire system smaller and more stable is
* to change the interface between assembler, define_label(), and
* the output module. The changes that are needed are:
*
* The semantics of the 'isextern' flag passed to define_label() need
* examining. This information may or may not tell us what we need to
* know (ie should we be generating an import record at this point for this
* label). If these aren't the semantics, the semantics should be changed
* to this.
*
* The output module interface needs changing, so that the `isextern' flag
* is passed to the module, so that it can be easily tested for.
*/