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go/src/cmd/6l/obj.c
Russ Cox 0cb0f6d090 cmd/ld: support for linking with host linker 
A step toward a fix for issue 4069.

To allow linking with arbitrary host object files, add a linker mode
that can generate a host object file instead of an executable.
Then the host linker can be invoked to generate the final executable.

This CL adds a new -hostobj flag that instructs the linker to write
a host object file instead of an executable.

That is, this works:

        go tool 6g x.go
        go tool 6l -hostobj -o x.o x.6
        ld -e _rt0_amd64_linux x.o
        ./a.out

as does:

        go tool 8g x.go
        go tool 8l -hostld ignored -o x.o x.8
        ld -m elf_i386 -e _rt0_386_linux x.o
        ./a.out

Because 5l was never updated to use the standard relocation scheme,
it will take more work to get this working on ARM.

This is a checkpoint of the basic functionality. It does not work
with cgo yet, and cgo is the main reason for the change.
The command-line interface will likely change too.
The gc linker has other information that needs to be returned to
the caller for use when invoking the host linker besides the single
object file.

R=iant, iant
CC=golang-dev
https://golang.org/cl/7060044
2013-01-31 14:11:32 -08:00

770 lines
16 KiB
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// Inferno utils/6l/obj.c
// http://code.google.com/p/inferno-os/source/browse/utils/6l/obj.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.
// Reading object files.
#define EXTERN
#include "l.h"
#include "../ld/lib.h"
#include "../ld/elf.h"
#include "../ld/macho.h"
#include "../ld/dwarf.h"
#include "../ld/pe.h"
#include <ar.h>
char *noname = "<none>";
char* thestring = "amd64";
char* paramspace = "FP";
Header headers[] = {
"plan9x32", Hplan9x32,
"plan9", Hplan9x64,
"elf", Helf,
"darwin", Hdarwin,
"linux", Hlinux,
"freebsd", Hfreebsd,
"netbsd", Hnetbsd,
"openbsd", Hopenbsd,
"windows", Hwindows,
"windowsgui", Hwindows,
0, 0
};
/*
* -Hplan9x32 -T4128 -R4096 is plan9 32-bit format
* -Hplan9 -T0x200028 -R0x200000 is plan9 64-bit format
* -Helf -T0x80110000 -R4096 is ELF32
* -Hdarwin -Tx -Rx is apple MH-exec
* -Hlinux -Tx -Rx is linux elf-exec
* -Hfreebsd -Tx -Rx is FreeBSD elf-exec
* -Hnetbsd -Tx -Rx is NetBSD elf-exec
* -Hopenbsd -Tx -Rx is OpenBSD elf-exec
* -Hwindows -Tx -Rx is MS Windows PE32+
*/
void
main(int argc, char *argv[])
{
Binit(&bso, 1, OWRITE);
listinit();
memset(debug, 0, sizeof(debug));
nerrors = 0;
outfile = nil;
HEADTYPE = -1;
INITTEXT = -1;
INITDAT = -1;
INITRND = -1;
INITENTRY = 0;
LIBINITENTRY = 0;
nuxiinit();
flagcount("1", "use alternate profiling code", &debug['1']);
flagcount("8", "assume 64-bit addresses", &debug['8']);
flagfn1("B", "info: define ELF NT_GNU_BUILD_ID note", addbuildinfo);
flagint64("D", "addr: data address", &INITDAT);
flagstr("E", "sym: entry symbol", &INITENTRY);
flagfn1("I", "interp: set ELF interp", setinterp);
flagfn1("L", "dir: add dir to library path", Lflag);
flagfn1("H", "head: header type", setheadtype);
flagcount("K", "add stack underflow checks", &debug['K']);
flagcount("O", "print pc-line tables", &debug['O']);
flagcount("Q", "debug byte-register code gen", &debug['Q']);
flagint32("R", "rnd: address rounding", &INITRND);
flagcount("S", "check type signatures", &debug['S']);
flagint64("T", "addr: text address", &INITTEXT);
flagfn0("V", "print version and exit", doversion);
flagcount("W", "disassemble input", &debug['W']);
flagfn2("X", "name value: define string data", addstrdata);
flagcount("Z", "clear stack frame on entry", &debug['Z']);
flagcount("a", "disassemble output", &debug['a']);
flagcount("c", "dump call graph", &debug['c']);
flagcount("d", "disable dynamic executable", &debug['d']);
flagcount("f", "ignore version mismatch", &debug['f']);
flagcount("g", "disable go package data checks", &debug['g']);
flagcount("hostobj", "generate host object file", &isobj);
flagstr("k", "sym: set field tracking symbol", &tracksym);
flagcount("n", "dump symbol table", &debug['n']);
flagstr("o", "outfile: set output file", &outfile);
flagcount("p", "insert profiling code", &debug['p']);
flagstr("r", "dir1:dir2:...: set ELF dynamic linker search path", &rpath);
flagcount("race", "enable race detector", &flag_race);
flagcount("s", "disable symbol table", &debug['s']);
flagcount("u", "reject unsafe packages", &debug['u']);
flagcount("v", "print link trace", &debug['v']);
flagcount("w", "disable DWARF generation", &debug['w']);
flagcount("shared", "generate shared object", &flag_shared);
flagparse(&argc, &argv, usage);
if(argc != 1)
usage();
mywhatsys(); // get goos
if(HEADTYPE == -1)
HEADTYPE = headtype(goos);
if(isobj) {
switch(HEADTYPE) {
default:
sysfatal("cannot use -hostobj with -H %s", headstr(HEADTYPE));
case Hlinux:
break;
}
}
if(outfile == nil) {
if(HEADTYPE == Hwindows)
outfile = "6.out.exe";
else
outfile = "6.out";
}
libinit();
switch(HEADTYPE) {
default:
diag("unknown -H option");
errorexit();
case Hplan9x32: /* plan 9 */
HEADR = 32L;
if(INITTEXT == -1)
INITTEXT = 4096+HEADR;
if(INITDAT == -1)
INITDAT = 0;
if(INITRND == -1)
INITRND = 4096;
break;
case Hplan9x64: /* plan 9 */
HEADR = 32L + 8L;
if(INITTEXT == -1)
INITTEXT = 0x200000+HEADR;
if(INITDAT == -1)
INITDAT = 0;
if(INITRND == -1)
INITRND = 0x200000;
break;
case Helf: /* elf32 executable */
HEADR = rnd(52L+3*32L, 16);
if(INITTEXT == -1)
INITTEXT = 0x80110000L;
if(INITDAT == -1)
INITDAT = 0;
if(INITRND == -1)
INITRND = 4096;
break;
case Hdarwin: /* apple MACH */
/*
* OS X system constant - offset from 0(GS) to our TLS.
* Explained in ../../pkg/runtime/cgo/gcc_darwin_amd64.c.
*/
tlsoffset = 0x8a0;
machoinit();
HEADR = INITIAL_MACHO_HEADR;
if(INITRND == -1)
INITRND = 4096;
if(INITTEXT == -1)
INITTEXT = 4096+HEADR;
if(INITDAT == -1)
INITDAT = 0;
break;
case Hlinux: /* elf64 executable */
case Hfreebsd: /* freebsd */
case Hnetbsd: /* netbsd */
case Hopenbsd: /* openbsd */
/*
* ELF uses TLS offset negative from FS.
* Translate 0(FS) and 8(FS) into -16(FS) and -8(FS).
* Also known to ../../pkg/runtime/sys_linux_amd64.s
* and ../../pkg/runtime/cgo/gcc_linux_amd64.c.
*/
tlsoffset = -16;
elfinit();
HEADR = ELFRESERVE;
if(INITTEXT == -1)
INITTEXT = (1<<22)+HEADR;
if(INITDAT == -1)
INITDAT = 0;
if(INITRND == -1)
INITRND = 4096;
break;
case Hwindows: /* PE executable */
peinit();
HEADR = PEFILEHEADR;
if(INITTEXT == -1)
INITTEXT = PEBASE+PESECTHEADR;
if(INITDAT == -1)
INITDAT = 0;
if(INITRND == -1)
INITRND = PESECTALIGN;
break;
}
if(INITDAT != 0 && INITRND != 0)
print("warning: -D0x%llux is ignored because of -R0x%ux\n",
INITDAT, INITRND);
if(debug['v'])
Bprint(&bso, "HEADER = -H%d -T0x%llux -D0x%llux -R0x%ux\n",
HEADTYPE, INITTEXT, INITDAT, INITRND);
Bflush(&bso);
instinit();
zprg.link = P;
zprg.pcond = P;
zprg.back = 2;
zprg.as = AGOK;
zprg.from.type = D_NONE;
zprg.from.index = D_NONE;
zprg.from.scale = 1;
zprg.to = zprg.from;
zprg.mode = 64;
pcstr = "%.6llux ";
histgen = 0;
pc = 0;
dtype = 4;
version = 0;
cbp = buf.cbuf;
cbc = sizeof(buf.cbuf);
addlibpath("command line", "command line", argv[0], "main");
loadlib();
deadcode();
patch();
follow();
doelf();
if(HEADTYPE == Hdarwin)
domacho();
dostkoff();
dostkcheck();
paramspace = "SP"; /* (FP) now (SP) on output */
if(debug['p'])
if(debug['1'])
doprof1();
else
doprof2();
span();
if(HEADTYPE == Hwindows)
dope();
addexport();
textaddress();
pclntab();
symtab();
dodata();
address();
doweak();
reloc();
asmb();
undef();
if(debug['v']) {
Bprint(&bso, "%5.2f cpu time\n", cputime());
Bprint(&bso, "%d symbols\n", nsymbol);
Bprint(&bso, "%d sizeof adr\n", sizeof(Adr));
Bprint(&bso, "%d sizeof prog\n", sizeof(Prog));
}
Bflush(&bso);
errorexit();
}
static Sym*
zsym(char *pn, Biobuf *f, Sym *h[])
{
int o;
o = BGETC(f);
if(o < 0 || o >= NSYM || h[o] == nil)
mangle(pn);
return h[o];
}
static void
zaddr(char *pn, Biobuf *f, Adr *a, Sym *h[])
{
int t;
int32 l;
Sym *s;
Auto *u;
t = BGETC(f);
a->index = D_NONE;
a->scale = 0;
if(t & T_INDEX) {
a->index = BGETC(f);
a->scale = BGETC(f);
}
a->offset = 0;
if(t & T_OFFSET) {
a->offset = Bget4(f);
if(t & T_64) {
a->offset &= 0xFFFFFFFFULL;
a->offset |= (vlong)Bget4(f) << 32;
}
}
a->sym = S;
if(t & T_SYM)
a->sym = zsym(pn, f, h);
a->type = D_NONE;
if(t & T_FCONST) {
a->ieee.l = Bget4(f);
a->ieee.h = Bget4(f);
a->type = D_FCONST;
} else
if(t & T_SCONST) {
Bread(f, a->scon, NSNAME);
a->type = D_SCONST;
}
if(t & T_TYPE)
a->type = BGETC(f);
if(a->type < 0 || a->type >= D_SIZE)
mangle(pn);
adrgotype = S;
if(t & T_GOTYPE)
adrgotype = zsym(pn, f, h);
s = a->sym;
t = a->type;
if(t == D_INDIR+D_GS)
a->offset += tlsoffset;
if(t != D_AUTO && t != D_PARAM) {
if(s && adrgotype)
s->gotype = adrgotype;
return;
}
l = a->offset;
for(u=curauto; u; u=u->link) {
if(u->asym == s)
if(u->type == t) {
if(u->aoffset > l)
u->aoffset = l;
if(adrgotype)
u->gotype = adrgotype;
return;
}
}
switch(t) {
case D_FILE:
case D_FILE1:
case D_AUTO:
case D_PARAM:
if(s == S)
mangle(pn);
}
u = mal(sizeof(*u));
u->link = curauto;
curauto = u;
u->asym = s;
u->aoffset = l;
u->type = t;
u->gotype = adrgotype;
}
void
nopout(Prog *p)
{
p->as = ANOP;
p->from.type = D_NONE;
p->to.type = D_NONE;
}
void
ldobj1(Biobuf *f, char *pkg, int64 len, char *pn)
{
vlong ipc;
Prog *p;
int v, o, r, skip, mode;
Sym *h[NSYM], *s;
uint32 sig;
char *name, *x;
int ntext;
vlong eof;
char src[1024];
Prog *lastp;
lastp = nil;
ntext = 0;
eof = Boffset(f) + len;
src[0] = 0;
newloop:
memset(h, 0, sizeof(h));
version++;
histfrogp = 0;
ipc = pc;
skip = 0;
mode = 64;
loop:
if(f->state == Bracteof || Boffset(f) >= eof)
goto eof;
o = BGETC(f);
if(o == Beof)
goto eof;
o |= BGETC(f) << 8;
if(o <= AXXX || o >= ALAST) {
if(o < 0)
goto eof;
diag("%s:#%lld: opcode out of range: %#ux", pn, Boffset(f), o);
print(" probably not a .6 file\n");
errorexit();
}
if(o == ANAME || o == ASIGNAME) {
sig = 0;
if(o == ASIGNAME)
sig = Bget4(f);
v = BGETC(f); /* type */
o = BGETC(f); /* sym */
r = 0;
if(v == D_STATIC)
r = version;
name = Brdline(f, '\0');
if(name == nil) {
if(Blinelen(f) > 0) {
fprint(2, "%s: name too long\n", pn);
errorexit();
}
goto eof;
}
x = expandpkg(name, pkg);
s = lookup(x, r);
if(x != name)
free(x);
if(debug['S'] && r == 0)
sig = 1729;
if(sig != 0){
if(s->sig != 0 && s->sig != sig)
diag("incompatible type signatures "
"%ux(%s) and %ux(%s) for %s",
s->sig, s->file, sig, pn, s->name);
s->sig = sig;
s->file = pn;
}
if(debug['W'])
print(" ANAME %s\n", s->name);
if(o < 0 || o >= nelem(h))
mangle(pn);
h[o] = s;
if((v == D_EXTERN || v == D_STATIC) && s->type == 0)
s->type = SXREF;
if(v == D_FILE) {
if(s->type != SFILE) {
histgen++;
s->type = SFILE;
s->value = histgen;
}
if(histfrogp < MAXHIST) {
histfrog[histfrogp] = s;
histfrogp++;
} else
collapsefrog(s);
dwarfaddfrag(s->value, s->name);
}
goto loop;
}
p = mal(sizeof(*p));
p->as = o;
p->line = Bget4(f);
p->back = 2;
p->mode = mode;
zaddr(pn, f, &p->from, h);
fromgotype = adrgotype;
zaddr(pn, f, &p->to, h);
switch(p->as) {
case ATEXT:
case ADATA:
case AGLOBL:
if(p->from.sym == S)
mangle(pn);
break;
}
if(debug['W'])
print("%P\n", p);
switch(p->as) {
case AHISTORY:
if(p->to.offset == -1) {
addlib(src, pn);
histfrogp = 0;
goto loop;
}
if(src[0] == '\0')
copyhistfrog(src, sizeof src);
addhist(p->line, D_FILE); /* 'z' */
if(p->to.offset)
addhist(p->to.offset, D_FILE1); /* 'Z' */
histfrogp = 0;
goto loop;
case AEND:
histtoauto();
if(cursym != nil && cursym->text)
cursym->autom = curauto;
curauto = 0;
cursym = nil;
if(Boffset(f) == eof)
return;
goto newloop;
case AGLOBL:
s = p->from.sym;
if(s->type == 0 || s->type == SXREF) {
s->type = SBSS;
s->size = 0;
}
if(s->type != SBSS && s->type != SNOPTRBSS && !s->dupok) {
diag("%s: redefinition: %s in %s",
pn, s->name, TNAME);
s->type = SBSS;
s->size = 0;
}
if(p->to.offset > s->size)
s->size = p->to.offset;
if(p->from.scale & DUPOK)
s->dupok = 1;
if(p->from.scale & RODATA)
s->type = SRODATA;
else if(p->from.scale & NOPTR)
s->type = SNOPTRBSS;
goto loop;
case ADATA:
// Assume that AGLOBL comes after ADATA.
// If we've seen an AGLOBL that said this sym was DUPOK,
// ignore any more ADATA we see, which must be
// redefinitions.
s = p->from.sym;
if(s->dupok) {
// if(debug['v'])
// Bprint(&bso, "skipping %s in %s: dupok\n", s->name, pn);
goto loop;
}
if(s->file == nil)
s->file = pn;
else if(s->file != pn) {
diag("multiple initialization for %s: in both %s and %s", s->name, s->file, pn);
errorexit();
}
savedata(s, p, pn);
unmal(p, sizeof *p);
goto loop;
case AGOK:
diag("%s: GOK opcode in %s", pn, TNAME);
pc++;
goto loop;
case ATEXT:
s = p->from.sym;
if(s->text != nil) {
if(p->from.scale & DUPOK) {
skip = 1;
goto casdef;
}
diag("%s: %s: redefinition", pn, s->name);
return;
}
if(ntext++ == 0 && s->type != 0 && s->type != SXREF) {
/* redefinition, so file has probably been seen before */
if(debug['v'])
Bprint(&bso, "skipping: %s: redefinition: %s", pn, s->name);
return;
}
if(cursym != nil && cursym->text) {
histtoauto();
cursym->autom = curauto;
curauto = 0;
}
skip = 0;
if(etextp)
etextp->next = s;
else
textp = s;
etextp = s;
s->text = p;
cursym = s;
if(s->type != 0 && s->type != SXREF) {
if(p->from.scale & DUPOK) {
skip = 1;
goto casdef;
}
diag("%s: redefinition: %s\n%P", pn, s->name, p);
}
if(fromgotype) {
if(s->gotype && s->gotype != fromgotype)
diag("%s: type mismatch for %s", pn, s->name);
s->gotype = fromgotype;
}
s->type = STEXT;
s->value = pc;
lastp = p;
p->pc = pc++;
goto loop;
case AMODE:
if(p->from.type == D_CONST || p->from.type == D_INDIR+D_NONE){
switch((int)p->from.offset){
case 16: case 32: case 64:
mode = p->from.offset;
break;
}
}
goto loop;
case AFMOVF:
case AFADDF:
case AFSUBF:
case AFSUBRF:
case AFMULF:
case AFDIVF:
case AFDIVRF:
case AFCOMF:
case AFCOMFP:
case AMOVSS:
case AADDSS:
case ASUBSS:
case AMULSS:
case ADIVSS:
case ACOMISS:
case AUCOMISS:
if(skip)
goto casdef;
if(p->from.type == D_FCONST) {
/* size sb 9 max */
sprint(literal, "$%ux", ieeedtof(&p->from.ieee));
s = lookup(literal, 0);
if(s->type == 0) {
s->type = SRODATA;
adduint32(s, ieeedtof(&p->from.ieee));
s->reachable = 0;
}
p->from.type = D_EXTERN;
p->from.sym = s;
p->from.offset = 0;
}
goto casdef;
case AFMOVD:
case AFADDD:
case AFSUBD:
case AFSUBRD:
case AFMULD:
case AFDIVD:
case AFDIVRD:
case AFCOMD:
case AFCOMDP:
case AMOVSD:
case AADDSD:
case ASUBSD:
case AMULSD:
case ADIVSD:
case ACOMISD:
case AUCOMISD:
if(skip)
goto casdef;
if(p->from.type == D_FCONST) {
/* size sb 18 max */
sprint(literal, "$%ux.%ux",
p->from.ieee.l, p->from.ieee.h);
s = lookup(literal, 0);
if(s->type == 0) {
s->type = SRODATA;
adduint32(s, p->from.ieee.l);
adduint32(s, p->from.ieee.h);
s->reachable = 0;
}
p->from.type = D_EXTERN;
p->from.sym = s;
p->from.offset = 0;
}
goto casdef;
casdef:
default:
if(skip)
nopout(p);
p->pc = pc;
pc++;
if(p->to.type == D_BRANCH)
p->to.offset += ipc;
if(lastp == nil) {
if(p->as != ANOP)
diag("unexpected instruction: %P", p);
goto loop;
}
lastp->link = p;
lastp = p;
goto loop;
}
eof:
diag("truncated object file: %s", pn);
}
Prog*
prg(void)
{
Prog *p;
p = mal(sizeof(*p));
*p = zprg;
return p;
}
Prog*
copyp(Prog *q)
{
Prog *p;
p = prg();
*p = *q;
return p;
}
Prog*
appendp(Prog *q)
{
Prog *p;
p = prg();
p->link = q->link;
q->link = p;
p->line = q->line;
p->mode = q->mode;
return p;
}
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