ref: f3b27fd889ff31531ecd69bbfd1013c9ba57814e
dir: /sys/src/libmach/obj.c/
/*
* obj.c
* routines universal to all object files
*/
#include <u.h>
#include <libc.h>
#include <bio.h>
#include <ar.h>
#include <mach.h>
#include "obj.h"
#define islocal(t) ((t)=='a' || (t)=='p')
enum
{
NNAMES = 50,
MAXIS = 8, /* max length to determine if a file is a .? file */
MAXOFF = 0x7fffffff, /* larger than any possible local offset */
NHASH = 1024, /* must be power of two */
HASHMUL = 79L,
};
int _is2(char*), /* in [$OS].c */
_is5(char*),
_is6(char*),
_is7(char*),
_is8(char*),
_is9(char*),
_isk(char*),
_isq(char*),
_isv(char*),
_isu(char*),
_read2(Biobuf*, Prog*),
_read5(Biobuf*, Prog*),
_read6(Biobuf*, Prog*),
_read8(Biobuf*, Prog*),
_read9(Biobuf*, Prog*),
_readk(Biobuf*, Prog*),
_readq(Biobuf*, Prog*),
_readv(Biobuf*, Prog*),
_readu(Biobuf*, Prog*);
typedef struct Obj Obj;
typedef struct Symtab Symtab;
struct Obj /* functions to handle each intermediate (.$O) file */
{
char *name; /* name of each $O file */
int (*is)(char*); /* test for each type of $O file */
int (*read)(Biobuf*, Prog*); /* read for each type of $O file*/
};
static Obj obj[] =
{ /* functions to identify and parse each type of obj */
[Obj68020] "68020 .2", _is2, _read2,
[ObjAmd64] "amd64 .6", _is6, _read6,
[ObjArm] "arm .5", _is5, _read5,
[Obj386] "386 .8", _is8, _read8,
[ObjSparc] "sparc .k", _isk, _readk,
[ObjPower] "power .q", _isq, _readq,
[ObjMips] "mips .v", _isv, _readv,
[ObjSparc64] "sparc64 .u", _isu, _readu,
[ObjPower64] "power64 .9", _is9, _read9,
[Maxobjtype] 0, 0
};
struct Symtab
{
struct Sym s;
struct Symtab *next;
};
static Symtab *hash[NHASH];
static Sym *names[NNAMES]; /* working set of active names */
static int processprog(Prog*,int); /* decode each symbol reference */
static void objreset(void);
static void objlookup(int, char *, int, uint);
static void objupdate(int, int);
int
objtype(Biobuf *bp, char **name)
{
int i;
char buf[MAXIS];
if(Bread(bp, buf, MAXIS) < MAXIS)
return -1;
Bseek(bp, -MAXIS, 1);
for (i = 0; i < Maxobjtype; i++) {
if (obj[i].is && (*obj[i].is)(buf)) {
if (name)
*name = obj[i].name;
return i;
}
}
return -1;
}
int
isar(Biobuf *bp)
{
int n;
char magbuf[SARMAG];
n = Bread(bp, magbuf, SARMAG);
if(n == SARMAG && strncmp(magbuf, ARMAG, SARMAG) == 0)
return 1;
return 0;
}
/*
* determine what kind of object file this is and process it.
* return whether or not this was a recognized intermediate file.
*/
int
readobj(Biobuf *bp, int objtype)
{
Prog p;
if (objtype < 0 || objtype >= Maxobjtype || obj[objtype].is == 0)
return 1;
objreset();
while ((*obj[objtype].read)(bp, &p))
if (!processprog(&p, 1))
return 0;
return 1;
}
int
readar(Biobuf *bp, int objtype, vlong end, int doautos)
{
Prog p;
if (objtype < 0 || objtype >= Maxobjtype || obj[objtype].is == 0)
return 1;
objreset();
while ((*obj[objtype].read)(bp, &p) && Boffset(bp) < end)
if (!processprog(&p, doautos))
return 0;
return 1;
}
/*
* decode a symbol reference or definition
*/
static int
processprog(Prog *p, int doautos)
{
if(p->kind == aNone)
return 1;
if(p->sym < 0 || p->sym >= NNAMES)
return 0;
switch(p->kind)
{
case aName:
if (!doautos)
if(p->type != 'U' && p->type != 'b')
break;
objlookup(p->sym, p->id, p->type, p->sig);
break;
case aText:
objupdate(p->sym, 'T');
break;
case aData:
objupdate(p->sym, 'D');
break;
default:
break;
}
return 1;
}
/*
* find the entry for s in the symbol array.
* make a new entry if it is not already there.
*/
static void
objlookup(int id, char *name, int type, uint sig)
{
long h;
char *cp;
Sym *s;
Symtab *sp;
s = names[id];
if(s && strcmp(s->name, name) == 0) {
s->type = type;
s->sig = sig;
return;
}
h = *name;
for(cp = name+1; *cp; h += *cp++)
h *= HASHMUL;
if(h < 0)
h = ~h;
h &= (NHASH-1);
if (type == 'U' || type == 'b' || islocal(type)) {
for(sp = hash[h]; sp; sp = sp->next)
if(strcmp(sp->s.name, name) == 0) {
switch(sp->s.type) {
case 'T':
case 'D':
case 'U':
if (type == 'U') {
names[id] = &sp->s;
return;
}
break;
case 't':
case 'd':
case 'b':
if (type == 'b') {
names[id] = &sp->s;
return;
}
break;
case 'a':
case 'p':
if (islocal(type)) {
names[id] = &sp->s;
return;
}
break;
default:
break;
}
}
}
sp = malloc(sizeof(Symtab));
sp->s.name = name;
sp->s.type = type;
sp->s.sig = sig;
sp->s.value = islocal(type) ? MAXOFF : 0;
names[id] = &sp->s;
sp->next = hash[h];
hash[h] = sp;
return;
}
/*
* traverse the symbol lists
*/
void
objtraverse(void (*fn)(Sym*, void*), void *pointer)
{
int i;
Symtab *s;
for(i = 0; i < NHASH; i++)
for(s = hash[i]; s; s = s->next)
(*fn)(&s->s, pointer);
}
/*
* update the offset information for a 'a' or 'p' symbol in an intermediate file
*/
void
_offset(int id, vlong off)
{
Sym *s;
s = names[id];
if (s && s->name[0] && islocal(s->type) && s->value > off)
s->value = off;
}
/*
* update the type of a global text or data symbol
*/
static void
objupdate(int id, int type)
{
Sym *s;
s = names[id];
if (s && s->name[0])
if (s->type == 'U')
s->type = type;
else if (s->type == 'b')
s->type = tolower(type);
}
/*
* look for the next file in an archive
*/
int
nextar(Biobuf *bp, int offset, char *buf)
{
struct ar_hdr a;
int i, r;
long arsize;
if (offset&01)
offset++;
Bseek(bp, offset, 0);
r = Bread(bp, &a, SAR_HDR);
if(r != SAR_HDR)
return 0;
if(strncmp(a.fmag, ARFMAG, sizeof(a.fmag)))
return -1;
for(i=0; i<sizeof(a.name) && i<SARNAME && a.name[i] != ' '; i++)
buf[i] = a.name[i];
buf[i] = 0;
arsize = strtol(a.size, 0, 0);
if (arsize&1)
arsize++;
return arsize + SAR_HDR;
}
static void
objreset(void)
{
int i;
Symtab *s, *n;
for(i = 0; i < NHASH; i++) {
for(s = hash[i]; s; s = n) {
n = s->next;
free(s->s.name);
free(s);
}
hash[i] = 0;
}
memset(names, 0, sizeof names);
}