// Inferno utils/8l/asm.c
// http://code.google.com/p/inferno-os/source/browse/utils/8l/asm.c
//
// Copyright © 1994-1999 Lucent Technologies Inc. All rights reserved.
// Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
// Portions Copyright © 1997-1999 Vita Nuova Limited
// Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
// Portions Copyright © 2004,2006 Bruce Ellis
// Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
// Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
// Portions Copyright © 2009 The Go Authors. All rights reserved.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
// Writing object files.
#include "l.h"
#include "../ld/lib.h"
#include "../ld/elf.h"
#include "../ld/dwarf.h"
#include "../ld/macho.h"
#include "../ld/pe.h"
char linuxdynld[] = "/lib/ld-linux.so.2";
char freebsddynld[] = "/usr/libexec/ld-elf.so.1";
char openbsddynld[] = "/usr/libexec/ld.so";
char netbsddynld[] = "/usr/libexec/ld.elf_so";
char dragonflydynld[] = "/usr/libexec/ld-elf.so.2";
char solarisdynld[] = "/lib/ld.so.1";
static int
needlib(char *name)
{
char *p;
LSym *s;
if(*name == '\0')
return 0;
/* reuse hash code in symbol table */
p = smprint(".dynlib.%s", name);
s = linklookup(ctxt, p, 0);
free(p);
if(s->type == 0) {
s->type = 100; // avoid SDATA, etc.
return 1;
}
return 0;
}
int nelfsym = 1;
static void addpltsym(Link*, LSym*);
static void addgotsym(Link*, LSym*);
void
adddynrela(LSym *rela, LSym *s, Reloc *r)
{
USED(rela);
USED(s);
USED(r);
sysfatal("adddynrela not implemented");
}
void
adddynrel(LSym *s, Reloc *r)
{
LSym *targ, *rel, *got;
targ = r->sym;
ctxt->cursym = s;
switch(r->type) {
default:
if(r->type >= 256) {
diag("unexpected relocation type %d", r->type);
return;
}
break;
// Handle relocations found in ELF object files.
case 256 + R_386_PC32:
if(targ->type == SDYNIMPORT)
diag("unexpected R_386_PC32 relocation for dynamic symbol %s", targ->name);
if(targ->type == 0 || targ->type == SXREF)
diag("unknown symbol %s in pcrel", targ->name);
r->type = R_PCREL;
r->add += 4;
return;
case 256 + R_386_PLT32:
r->type = R_PCREL;
r->add += 4;
if(targ->type == SDYNIMPORT) {
addpltsym(ctxt, targ);
r->sym = linklookup(ctxt, ".plt", 0);
r->add += targ->plt;
}
return;
case 256 + R_386_GOT32:
if(targ->type != SDYNIMPORT) {
// have symbol
// turn MOVL of GOT entry into LEAL of symbol itself
if(r->off < 2 || s->p[r->off-2] != 0x8b) {
diag("unexpected GOT reloc for non-dynamic symbol %s", targ->name);
return;
}
s->p[r->off-2] = 0x8d;
r->type = R_GOTOFF;
return;
}
addgotsym(ctxt, targ);
r->type = R_CONST; // write r->add during relocsym
r->sym = S;
r->add += targ->got;
return;
case 256 + R_386_GOTOFF:
r->type = R_GOTOFF;
return;
case 256 + R_386_GOTPC:
r->type = R_PCREL;
r->sym = linklookup(ctxt, ".got", 0);
r->add += 4;
return;
case 256 + R_386_32:
if(targ->type == SDYNIMPORT)
diag("unexpected R_386_32 relocation for dynamic symbol %s", targ->name);
r->type = R_ADDR;
return;
case 512 + MACHO_GENERIC_RELOC_VANILLA*2 + 0:
r->type = R_ADDR;
if(targ->type == SDYNIMPORT)
diag("unexpected reloc for dynamic symbol %s", targ->name);
return;
case 512 + MACHO_GENERIC_RELOC_VANILLA*2 + 1:
if(targ->type == SDYNIMPORT) {
addpltsym(ctxt, targ);
r->sym = linklookup(ctxt, ".plt", 0);
r->add = targ->plt;
r->type = R_PCREL;
return;
}
r->type = R_PCREL;
return;
case 512 + MACHO_FAKE_GOTPCREL:
if(targ->type != SDYNIMPORT) {
// have symbol
// turn MOVL of GOT entry into LEAL of symbol itself
if(r->off < 2 || s->p[r->off-2] != 0x8b) {
diag("unexpected GOT reloc for non-dynamic symbol %s", targ->name);
return;
}
s->p[r->off-2] = 0x8d;
r->type = R_PCREL;
return;
}
addgotsym(ctxt, targ);
r->sym = linklookup(ctxt, ".got", 0);
r->add += targ->got;
r->type = R_PCREL;
return;
}
// Handle references to ELF symbols from our own object files.
if(targ->type != SDYNIMPORT)
return;
switch(r->type) {
case R_CALL:
case R_PCREL:
addpltsym(ctxt, targ);
r->sym = linklookup(ctxt, ".plt", 0);
r->add = targ->plt;
return;
case R_ADDR:
if(s->type != SDATA)
break;
if(iself) {
adddynsym(ctxt, targ);
rel = linklookup(ctxt, ".rel", 0);
addaddrplus(ctxt, rel, s, r->off);
adduint32(ctxt, rel, ELF32_R_INFO(targ->dynid, R_386_32));
r->type = R_CONST; // write r->add during relocsym
r->sym = S;
return;
}
if(HEADTYPE == Hdarwin && s->size == PtrSize && r->off == 0) {
// Mach-O relocations are a royal pain to lay out.
// They use a compact stateful bytecode representation
// that is too much bother to deal with.
// Instead, interpret the C declaration
// void *_Cvar_stderr = &stderr;
// as making _Cvar_stderr the name of a GOT entry
// for stderr. This is separate from the usual GOT entry,
// just in case the C code assigns to the variable,
// and of course it only works for single pointers,
// but we only need to support cgo and that's all it needs.
adddynsym(ctxt, targ);
got = linklookup(ctxt, ".got", 0);
s->type = got->type | SSUB;
s->outer = got;
s->sub = got->sub;
got->sub = s;
s->value = got->size;
adduint32(ctxt, got, 0);
adduint32(ctxt, linklookup(ctxt, ".linkedit.got", 0), targ->dynid);
r->type = 256; // ignore during relocsym
return;
}
break;
}
ctxt->cursym = s;
diag("unsupported relocation for dynamic symbol %s (type=%d stype=%d)", targ->name, r->type, targ->type);
}
int
elfreloc1(Reloc *r, vlong sectoff)
{
int32 elfsym;
LPUT(sectoff);
elfsym = r->xsym->elfsym;
switch(r->type) {
default:
return -1;
case R_ADDR:
if(r->siz == 4)
LPUT(R_386_32 | elfsym<<8);
else
return -1;
break;
case R_CALL:
case R_PCREL:
if(r->siz == 4)
LPUT(R_386_PC32 | elfsym<<8);
else
return -1;
break;
case R_TLS_LE:
case R_TLS_IE:
if(r->siz == 4)
LPUT(R_386_TLS_LE | elfsym<<8);
else
return -1;
}
return 0;
}
int
machoreloc1(Reloc *r, vlong sectoff)
{
uint32 v;
LSym *rs;
rs = r->xsym;
if(rs->type == SHOSTOBJ) {
if(rs->dynid < 0) {
diag("reloc %d to non-macho symbol %s type=%d", r->type, rs->name, rs->type);
return -1;
}
v = rs->dynid;
v |= 1<<27; // external relocation
} else {
v = rs->sect->extnum;
if(v == 0) {
diag("reloc %d to symbol %s in non-macho section %s type=%d", r->type, rs->name, rs->sect->name, rs->type);
return -1;
}
}
switch(r->type) {
default:
return -1;
case R_ADDR:
v |= MACHO_GENERIC_RELOC_VANILLA<<28;
break;
case R_CALL:
case R_PCREL:
v |= 1<<24; // pc-relative bit
v |= MACHO_GENERIC_RELOC_VANILLA<<28;
break;
}
switch(r->siz) {
default:
return -1;
case 1:
v |= 0<<25;
break;
case 2:
v |= 1<<25;
break;
case 4:
v |= 2<<25;
break;
case 8:
v |= 3<<25;
break;
}
LPUT(sectoff);
LPUT(v);
return 0;
}
int
archreloc(Reloc *r, LSym *s, vlong *val)
{
USED(s);
if(linkmode == LinkExternal)
return -1;
switch(r->type) {
case R_CONST:
*val = r->add;
return 0;
case R_GOTOFF:
*val = symaddr(r->sym) + r->add - symaddr(linklookup(ctxt, ".got", 0));
return 0;
}
return -1;
}
void
elfsetupplt(void)
{
LSym *plt, *got;
plt = linklookup(ctxt, ".plt", 0);
got = linklookup(ctxt, ".got.plt", 0);
if(plt->size == 0) {
// pushl got+4
adduint8(ctxt, plt, 0xff);
adduint8(ctxt, plt, 0x35);
addaddrplus(ctxt, plt, got, 4);
// jmp *got+8
adduint8(ctxt, plt, 0xff);
adduint8(ctxt, plt, 0x25);
addaddrplus(ctxt, plt, got, 8);
// zero pad
adduint32(ctxt, plt, 0);
// assume got->size == 0 too
addaddrplus(ctxt, got, linklookup(ctxt, ".dynamic", 0), 0);
adduint32(ctxt, got, 0);
adduint32(ctxt, got, 0);
}
}
static void
addpltsym(Link *ctxt, LSym *s)
{
LSym *plt, *got, *rel;
if(s->plt >= 0)
return;
adddynsym(ctxt, s);
if(iself) {
plt = linklookup(ctxt, ".plt", 0);
got = linklookup(ctxt, ".got.plt", 0);
rel = linklookup(ctxt, ".rel.plt", 0);
if(plt->size == 0)
elfsetupplt();
// jmpq *got+size
adduint8(ctxt, plt, 0xff);
adduint8(ctxt, plt, 0x25);
addaddrplus(ctxt, plt, got, got->size);
// add to got: pointer to current pos in plt
addaddrplus(ctxt, got, plt, plt->size);
// pushl $x
adduint8(ctxt, plt, 0x68);
adduint32(ctxt, plt, rel->size);
// jmp .plt
adduint8(ctxt, plt, 0xe9);
adduint32(ctxt, plt, -(plt->size+4));
// rel
addaddrplus(ctxt, rel, got, got->size-4);
adduint32(ctxt, rel, ELF32_R_INFO(s->dynid, R_386_JMP_SLOT));
s->plt = plt->size - 16;
} else if(HEADTYPE == Hdarwin) {
// Same laziness as in 6l.
LSym *plt;
plt = linklookup(ctxt, ".plt", 0);
addgotsym(ctxt, s);
adduint32(ctxt, linklookup(ctxt, ".linkedit.plt", 0), s->dynid);
// jmpq *got+size(IP)
s->plt = plt->size;
adduint8(ctxt, plt, 0xff);
adduint8(ctxt, plt, 0x25);
addaddrplus(ctxt, plt, linklookup(ctxt, ".got", 0), s->got);
} else {
diag("addpltsym: unsupported binary format");
}
}
static void
addgotsym(Link *ctxt, LSym *s)
{
LSym *got, *rel;
if(s->got >= 0)
return;
adddynsym(ctxt, s);
got = linklookup(ctxt, ".got", 0);
s->got = got->size;
adduint32(ctxt, got, 0);
if(iself) {
rel = linklookup(ctxt, ".rel", 0);
addaddrplus(ctxt, rel, got, s->got);
adduint32(ctxt, rel, ELF32_R_INFO(s->dynid, R_386_GLOB_DAT));
} else if(HEADTYPE == Hdarwin) {
adduint32(ctxt, linklookup(ctxt, ".linkedit.got", 0), s->dynid);
} else {
diag("addgotsym: unsupported binary format");
}
}
void
adddynsym(Link *ctxt, LSym *s)
{
LSym *d;
int t;
char *name;
if(s->dynid >= 0)
return;
if(iself) {
s->dynid = nelfsym++;
d = linklookup(ctxt, ".dynsym", 0);
/* name */
name = s->extname;
adduint32(ctxt, d, addstring(linklookup(ctxt, ".dynstr", 0), name));
/* value */
if(s->type == SDYNIMPORT)
adduint32(ctxt, d, 0);
else
addaddr(ctxt, d, s);
/* size */
adduint32(ctxt, d, 0);
/* type */
t = STB_GLOBAL << 4;
if(s->cgoexport && (s->type&SMASK) == STEXT)
t |= STT_FUNC;
else
t |= STT_OBJECT;
adduint8(ctxt, d, t);
adduint8(ctxt, d, 0);
/* shndx */
if(s->type == SDYNIMPORT)
adduint16(ctxt, d, SHN_UNDEF);
else {
switch(s->type) {
default:
case STEXT:
t = 11;
break;
case SRODATA:
t = 12;
break;
case SDATA:
t = 13;
break;
case SBSS:
t = 14;
break;
}
adduint16(ctxt, d, t);
}
} else if(HEADTYPE == Hdarwin) {
diag("adddynsym: missed symbol %s (%s)", s->name, s->extname);
} else if(HEADTYPE == Hwindows) {
// already taken care of
} else {
diag("adddynsym: unsupported binary format");
}
}
void
adddynlib(char *lib)
{
LSym *s;
if(!needlib(lib))
return;
if(iself) {
s = linklookup(ctxt, ".dynstr", 0);
if(s->size == 0)
addstring(s, "");
elfwritedynent(linklookup(ctxt, ".dynamic", 0), DT_NEEDED, addstring(s, lib));
} else if(HEADTYPE == Hdarwin) {
machoadddynlib(lib);
} else if(HEADTYPE != Hwindows) {
diag("adddynlib: unsupported binary format");
}
}
void
asmb(void)
{
int32 magic;
uint32 symo, dwarfoff, machlink;
Section *sect;
LSym *sym;
int i;
if(debug['v'])
Bprint(&bso, "%5.2f asmb\n", cputime());
Bflush(&bso);
if(iself)
asmbelfsetup();
sect = segtext.sect;
cseek(sect->vaddr - segtext.vaddr + segtext.fileoff);
codeblk(sect->vaddr, sect->len);
for(sect = sect->next; sect != nil; sect = sect->next) {
cseek(sect->vaddr - segtext.vaddr + segtext.fileoff);
datblk(sect->vaddr, sect->len);
}
if(segrodata.filelen > 0) {
if(debug['v'])
Bprint(&bso, "%5.2f rodatblk\n", cputime());
Bflush(&bso);
cseek(segrodata.fileoff);
datblk(segrodata.vaddr, segrodata.filelen);
}
if(debug['v'])
Bprint(&bso, "%5.2f datblk\n", cputime());
Bflush(&bso);
cseek(segdata.fileoff);
datblk(segdata.vaddr, segdata.filelen);
machlink = 0;
if(HEADTYPE == Hdarwin) {
if(debug['v'])
Bprint(&bso, "%5.2f dwarf\n", cputime());
dwarfoff = rnd(HEADR+segtext.len, INITRND) + rnd(segdata.filelen, INITRND);
cseek(dwarfoff);
segdwarf.fileoff = cpos();
dwarfemitdebugsections();
segdwarf.filelen = cpos() - segdwarf.fileoff;
machlink = domacholink();
}
symsize = 0;
spsize = 0;
lcsize = 0;
symo = 0;
if(!debug['s']) {
// TODO: rationalize
if(debug['v'])
Bprint(&bso, "%5.2f sym\n", cputime());
Bflush(&bso);
switch(HEADTYPE) {
default:
if(iself)
goto Elfsym;
case Hplan9:
symo = HEADR+segtext.filelen+segdata.filelen;
break;
case Hdarwin:
symo = rnd(HEADR+segtext.filelen, INITRND)+rnd(segdata.filelen, INITRND)+machlink;
break;
Elfsym:
symo = rnd(HEADR+segtext.filelen, INITRND)+rnd(HEADR+segrodata.filelen, INITRND)+segdata.filelen;
symo = rnd(symo, INITRND);
break;
case Hwindows:
symo = rnd(HEADR+segtext.filelen, PEFILEALIGN)+segdata.filelen;
symo = rnd(symo, PEFILEALIGN);
break;
}
cseek(symo);
switch(HEADTYPE) {
default:
if(iself) {
if(debug['v'])
Bprint(&bso, "%5.2f elfsym\n", cputime());
asmelfsym();
cflush();
cwrite(elfstrdat, elfstrsize);
if(debug['v'])
Bprint(&bso, "%5.2f dwarf\n", cputime());
dwarfemitdebugsections();
if(linkmode == LinkExternal)
elfemitreloc();
}
break;
case Hplan9:
asmplan9sym();
cflush();
sym = linklookup(ctxt, "pclntab", 0);
if(sym != nil) {
lcsize = sym->np;
for(i=0; i < lcsize; i++)
cput(sym->p[i]);
cflush();
}
break;
case Hwindows:
if(debug['v'])
Bprint(&bso, "%5.2f dwarf\n", cputime());
dwarfemitdebugsections();
break;
case Hdarwin:
if(linkmode == LinkExternal)
machoemitreloc();
break;
}
}
if(debug['v'])
Bprint(&bso, "%5.2f headr\n", cputime());
Bflush(&bso);
cseek(0L);
switch(HEADTYPE) {
default:
case Hplan9: /* plan9 */
magic = 4*11*11+7;
lputb(magic); /* magic */
lputb(segtext.filelen); /* sizes */
lputb(segdata.filelen);
lputb(segdata.len - segdata.filelen);
lputb(symsize); /* nsyms */
lputb(entryvalue()); /* va of entry */
lputb(spsize); /* sp offsets */
lputb(lcsize); /* line offsets */
break;
case Hdarwin:
asmbmacho();
break;
case Hlinux:
case Hfreebsd:
case Hnetbsd:
case Hopenbsd:
case Hdragonfly:
case Hnacl:
asmbelf(symo);
break;
case Hwindows:
asmbpe();
break;
}
cflush();
}
void
s8put(char *n)
{
char name[8];
int i;
strncpy(name, n, sizeof(name));
for(i=0; i<sizeof(name); i++)
cput(name[i]);
}
int32
rnd(int32 v, int32 r)
{
int32 c;
if(r <= 0)
return v;
v += r - 1;
c = v % r;
if(c < 0)
c += r;
v -= c;
return v;
}