src/cmd/ld/symtab.c - go - Git at Google

 // Inferno utils/6l/span.c
 // http://code.google.com/p/inferno-os/source/browse/utils/6l/span.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.

 // Symbol table.

 #include	<u.h>
 #include	<libc.h>
 #include	<bio.h>
 #include	<link.h>
 #include	"lib.h"
 #include	"elf.h"

 static int maxelfstr;

 static int
 putelfstr(char *s)
 {
 	int off, n;
 	char *p, *q;

 	if(elfstrsize == 0 && s[0] != 0) {
 		// first entry must be empty string
 		putelfstr("");
 	}

 	n = strlen(s)+1;
 	if(elfstrsize+n > maxelfstr) {
 		maxelfstr = 2*(elfstrsize+n+(1<<20));
 		elfstrdat = realloc(elfstrdat, maxelfstr);
 	}
 	off = elfstrsize;
 	elfstrsize += n;
 	memmove(elfstrdat+off, s, n);
 	// replace "·" as ".", because DTrace cannot handle it.
 	p = strstr(s, "·");
 	if(p != nil) {
 		p = q = elfstrdat+off;
 		while (*q != '\0') {
 			if((uchar)*q == 0xc2 && (uchar)*(q+1) == 0xb7) {
 				q += 2;
 				*p++ = '.';
 				elfstrsize--;
 			} else {
 				*p++ = *q++;
 			}
 		}
 		*p = '\0';
 	}
 	return off;
 }

 static void
 putelfsyment(int off, vlong addr, vlong size, int info, int shndx, int other)
 {
 	switch(thearch.thechar) {
 	case '6':
 	case '9':
 		thearch.lput(off);
 		cput(info);
 		cput(other);
 		thearch.wput(shndx);
 		thearch.vput(addr);
 		thearch.vput(size);
 		symsize += ELF64SYMSIZE;
 		break;
 	default:
 		thearch.lput(off);
 		thearch.lput(addr);
 		thearch.lput(size);
 		cput(info);
 		cput(other);
 		thearch.wput(shndx);
 		symsize += ELF32SYMSIZE;
 		break;
 	}
 }

 static int numelfsym = 1; // 0 is reserved
 static int elfbind;

 static void
 putelfsym(LSym *x, char *s, int t, vlong addr, vlong size, int ver, LSym *go)
 {
 	int bind, type, off;
 	LSym *xo;

 	USED(go);
 	switch(t) {
 	default:
 		return;
 	case 'T':
 		type = STT_FUNC;
 		break;
 	case 'D':
 		type = STT_OBJECT;
 		break;
 	case 'B':
 		type = STT_OBJECT;
 		break;
 	}
 	xo = x;
 	while(xo->outer != nil)
 		xo = xo->outer;
 	if(xo->sect == nil) {
 		ctxt->cursym = x;
 		diag("missing section in putelfsym");
 		return;
 	}
 	if(xo->sect->elfsect == nil) {
 		ctxt->cursym = x;
 		diag("missing ELF section in putelfsym");
 		return;
 	}

 	// One pass for each binding: STB_LOCAL, STB_GLOBAL,
 	// maybe one day STB_WEAK.
 	bind = STB_GLOBAL;
 	if(ver || (x->type & SHIDDEN))
 		bind = STB_LOCAL;

 	// In external linking mode, we have to invoke gcc with -rdynamic
 	// to get the exported symbols put into the dynamic symbol table.
 	// To avoid filling the dynamic table with lots of unnecessary symbols,
 	// mark all Go symbols local (not global) in the final executable.
 	if(linkmode == LinkExternal && !(x->cgoexport&CgoExportStatic))
 		bind = STB_LOCAL;

 	if(bind != elfbind)
 		return;

 	off = putelfstr(s);
 	if(linkmode == LinkExternal)
 		addr -= xo->sect->vaddr;
 	putelfsyment(off, addr, size, (bind<<4)|(type&0xf), xo->sect->elfsect->shnum, (x->type & SHIDDEN) ? 2 : 0);
 	x->elfsym = numelfsym++;
 }

 void
 putelfsectionsym(LSym* s, int shndx)
 {
 	putelfsyment(0, 0, 0, (STB_LOCAL<<4)|STT_SECTION, shndx, 0);
 	s->elfsym = numelfsym++;
 }

 void
 putelfsymshndx(vlong sympos, int shndx)
 {
 	vlong here;

 	here = cpos();
 	switch(thearch.thechar) {
 	case '6':
 		cseek(sympos+6);
 		break;
 	default:
 		cseek(sympos+14);
 		break;
 	}
 	thearch.wput(shndx);
 	cseek(here);
 }

 void
 asmelfsym(void)
 {
 	LSym *s;
 	char *name;

 	// the first symbol entry is reserved
 	putelfsyment(0, 0, 0, (STB_LOCAL<<4)|STT_NOTYPE, 0, 0);

 	dwarfaddelfsectionsyms();

 	elfbind = STB_LOCAL;
 	genasmsym(putelfsym);

 	if(linkmode == LinkExternal && HEADTYPE != Hopenbsd) {
 		s = linklookup(ctxt, "runtime.tlsg", 0);
 		if(s->sect == nil) {
 			ctxt->cursym = nil;
 			diag("missing section for %s", s->name);
 			errorexit();
 		}
 		if (strcmp(goos, "android") == 0) {
 			// Android emulates runtime.tlsg as a regular variable.
 			putelfsyment(putelfstr(s->name), 0, s->size, (STB_LOCAL<<4)|STT_OBJECT, s->sect->elfsect->shnum, 0);
 		} else {
 			putelfsyment(putelfstr(s->name), 0, s->size, (STB_LOCAL<<4)|STT_TLS, s->sect->elfsect->shnum, 0);
 		}
 		s->elfsym = numelfsym++;
 	}

 	elfbind = STB_GLOBAL;
 	elfglobalsymndx = numelfsym;
 	genasmsym(putelfsym);

 	for(s=ctxt->allsym; s!=nil; s=s->allsym) {
 		if(s->type != SHOSTOBJ && !(s->type == SDYNIMPORT && s->reachable))
 			continue;
 		if(s->type == SDYNIMPORT)
 			name = s->extname;
 		else
 			name = s->name;
 		putelfsyment(putelfstr(name), 0, 0, (STB_GLOBAL<<4)|STT_NOTYPE, 0, 0);
 		s->elfsym = numelfsym++;
 	}
 }

 static void
 putplan9sym(LSym *x, char *s, int t, vlong addr, vlong size, int ver, LSym *go)
 {
 	int i, l;

 	USED(go);
 	USED(ver);
 	USED(size);
 	USED(x);
 	switch(t) {
 	case 'T':
 	case 'L':
 	case 'D':
 	case 'B':
 		if(ver)
 			t += 'a' - 'A';
 	case 'a':
 	case 'p':
 	case 'f':
 	case 'z':
 	case 'Z':
 	case 'm':
 		l = 4;
 		if(HEADTYPE == Hplan9 && thearch.thechar == '6' && !debug['8']) {
 			lputb(addr>>32);
 			l = 8;
 		}
 		lputb(addr);
 		cput(t+0x80); /* 0x80 is variable length */

 		if(t == 'z' || t == 'Z') {
 			cput(s[0]);
 			for(i=1; s[i] != 0 || s[i+1] != 0; i += 2) {
 				cput(s[i]);
 				cput(s[i+1]);
 			}
 			cput(0);
 			cput(0);
 			i++;
 		} else {
 			/* skip the '<' in filenames */
 			if(t == 'f')
 				s++;
 			for(i=0; s[i]; i++)
 				cput(s[i]);
 			cput(0);
 		}
 		symsize += l + 1 + i + 1;
 		break;
 	default:
 		return;
 	};
 }

 void
 asmplan9sym(void)
 {
 	genasmsym(putplan9sym);
 }

 static LSym *symt;

 void
 wputl(ushort w)
 {
 	cput(w);
 	cput(w>>8);
 }

 void
 wputb(ushort w)
 {
 	cput(w>>8);
 	cput(w);
 }

 void
 lputb(uint32 l)
 {
 	cput(l>>24);
 	cput(l>>16);
 	cput(l>>8);
 	cput(l);
 }

 void
 lputl(uint32 l)
 {
 	cput(l);
 	cput(l>>8);
 	cput(l>>16);
 	cput(l>>24);
 }

 void
 vputb(uint64 v)
 {
 	lputb(v>>32);
 	lputb(v);
 }

 void
 vputl(uint64 v)
 {
 	lputl(v);
 	lputl(v >> 32);
 }

 void
 symtab(void)
 {
 	LSym *s, *symtype, *symtypelink, *symgostring, *symgofunc;

 	dosymtype();

 	// Define these so that they'll get put into the symbol table.
 	// data.c:/^address will provide the actual values.
 	xdefine("runtime.text", STEXT, 0);
 	xdefine("runtime.etext", STEXT, 0);
 	xdefine("runtime.typelink", SRODATA, 0);
 	xdefine("runtime.etypelink", SRODATA, 0);
 	xdefine("runtime.rodata", SRODATA, 0);
 	xdefine("runtime.erodata", SRODATA, 0);
 	xdefine("runtime.noptrdata", SNOPTRDATA, 0);
 	xdefine("runtime.enoptrdata", SNOPTRDATA, 0);
 	xdefine("runtime.data", SDATA, 0);
 	xdefine("runtime.edata", SDATA, 0);
 	xdefine("runtime.bss", SBSS, 0);
 	xdefine("runtime.ebss", SBSS, 0);
 	xdefine("runtime.noptrbss", SNOPTRBSS, 0);
 	xdefine("runtime.enoptrbss", SNOPTRBSS, 0);
 	xdefine("runtime.end", SBSS, 0);
 	xdefine("runtime.epclntab", SRODATA, 0);
 	xdefine("runtime.esymtab", SRODATA, 0);

 	// garbage collection symbols
 	s = linklookup(ctxt, "runtime.gcdata", 0);
 	s->type = SRODATA;
 	s->size = 0;
 	s->reachable = 1;
 	xdefine("runtime.egcdata", SRODATA, 0);

 	s = linklookup(ctxt, "runtime.gcbss", 0);
 	s->type = SRODATA;
 	s->size = 0;
 	s->reachable = 1;
 	xdefine("runtime.egcbss", SRODATA, 0);

 	// pseudo-symbols to mark locations of type, string, and go string data.
 	s = linklookup(ctxt, "type.*", 0);
 	s->type = STYPE;
 	s->size = 0;
 	s->reachable = 1;
 	symtype = s;

 	s = linklookup(ctxt, "go.string.*", 0);
 	s->type = SGOSTRING;
 	s->size = 0;
 	s->reachable = 1;
 	symgostring = s;

 	s = linklookup(ctxt, "go.func.*", 0);
 	s->type = SGOFUNC;
 	s->size = 0;
 	s->reachable = 1;
 	symgofunc = s;

 	symtypelink = linklookup(ctxt, "runtime.typelink", 0);

 	symt = linklookup(ctxt, "runtime.symtab", 0);
 	symt->type = SSYMTAB;
 	symt->size = 0;
 	symt->reachable = 1;

 	// assign specific types so that they sort together.
 	// within a type they sort by size, so the .* symbols
 	// just defined above will be first.
 	// hide the specific symbols.
 	for(s = ctxt->allsym; s != nil; s = s->allsym) {
 		if(!s->reachable || s->special || s->type != SRODATA)
 			continue;
 		if(strncmp(s->name, "type.", 5) == 0) {
 			s->type = STYPE;
 			s->hide = 1;
 			s->outer = symtype;
 		}
 		if(strncmp(s->name, "go.typelink.", 12) == 0) {
 			s->type = STYPELINK;
 			s->hide = 1;
 			s->outer = symtypelink;
 		}
 		if(strncmp(s->name, "go.string.", 10) == 0) {
 			s->type = SGOSTRING;
 			s->hide = 1;
 			s->outer = symgostring;
 		}
 		if(strncmp(s->name, "go.func.", 8) == 0) {
 			s->type = SGOFUNC;
 			s->hide = 1;
 			s->outer = symgofunc;
 		}
 		if(strncmp(s->name, "gcargs.", 7) == 0 || strncmp(s->name, "gclocals.", 9) == 0 || strncmp(s->name, "gclocals·", 10) == 0) {
 			s->type = SGOFUNC;
 			s->hide = 1;
 			s->outer = symgofunc;
 			s->align = 4;
 			liveness += (s->size+s->align-1)&~(s->align-1);
 		}
 	}
 }
	// Inferno utils/6l/span.c
	// http://code.google.com/p/inferno-os/source/browse/utils/6l/span.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.

	// Symbol table.

	#include <u.h>
	#include <libc.h>
	#include <bio.h>
	#include <link.h>
	#include "lib.h"
	#include "elf.h"

	static int maxelfstr;

	static int
	putelfstr(char *s)
	{
	int off, n;
	char p, q;

	if(elfstrsize == 0 && s[0] != 0) {
	// first entry must be empty string
	putelfstr("");
	}

	n = strlen(s)+1;
	if(elfstrsize+n > maxelfstr) {
	maxelfstr = 2*(elfstrsize+n+(1<<20));
	elfstrdat = realloc(elfstrdat, maxelfstr);
	}
	off = elfstrsize;
	elfstrsize += n;
	memmove(elfstrdat+off, s, n);
	// replace "·" as ".", because DTrace cannot handle it.
	p = strstr(s, "·");
	if(p != nil) {
	p = q = elfstrdat+off;
	while (*q != '\0') {
	if((uchar)q == 0xc2 && (uchar)(q+1) == 0xb7) {
	q += 2;
	*p++ = '.';
	elfstrsize--;
	} else {
	p++ = q++;
	}
	}
	*p = '\0';
	}
	return off;
	}

	static void
	putelfsyment(int off, vlong addr, vlong size, int info, int shndx, int other)
	{
	switch(thearch.thechar) {
	case '6':
	case '9':
	thearch.lput(off);
	cput(info);
	cput(other);
	thearch.wput(shndx);
	thearch.vput(addr);
	thearch.vput(size);
	symsize += ELF64SYMSIZE;
	break;
	default:
	thearch.lput(off);
	thearch.lput(addr);
	thearch.lput(size);
	cput(info);
	cput(other);
	thearch.wput(shndx);
	symsize += ELF32SYMSIZE;
	break;
	}
	}

	static int numelfsym = 1; // 0 is reserved
	static int elfbind;

	static void
	putelfsym(LSym x, char s, int t, vlong addr, vlong size, int ver, LSym *go)
	{
	int bind, type, off;
	LSym *xo;

	USED(go);
	switch(t) {
	default:
	return;
	case 'T':
	type = STT_FUNC;
	break;
	case 'D':
	type = STT_OBJECT;
	break;
	case 'B':
	type = STT_OBJECT;
	break;
	}
	xo = x;
	while(xo->outer != nil)
	xo = xo->outer;
	if(xo->sect == nil) {
	ctxt->cursym = x;
	diag("missing section in putelfsym");
	return;
	}
	if(xo->sect->elfsect == nil) {
	ctxt->cursym = x;
	diag("missing ELF section in putelfsym");
	return;
	}

	// One pass for each binding: STB_LOCAL, STB_GLOBAL,
	// maybe one day STB_WEAK.
	bind = STB_GLOBAL;
	if(ver \|\| (x->type & SHIDDEN))
	bind = STB_LOCAL;

	// In external linking mode, we have to invoke gcc with -rdynamic
	// to get the exported symbols put into the dynamic symbol table.
	// To avoid filling the dynamic table with lots of unnecessary symbols,
	// mark all Go symbols local (not global) in the final executable.
	if(linkmode == LinkExternal && !(x->cgoexport&CgoExportStatic))
	bind = STB_LOCAL;

	if(bind != elfbind)
	return;

	off = putelfstr(s);
	if(linkmode == LinkExternal)
	addr -= xo->sect->vaddr;
	putelfsyment(off, addr, size, (bind<<4)\|(type&0xf), xo->sect->elfsect->shnum, (x->type & SHIDDEN) ? 2 : 0);
	x->elfsym = numelfsym++;
	}

	void
	putelfsectionsym(LSym* s, int shndx)
	{
	putelfsyment(0, 0, 0, (STB_LOCAL<<4)\|STT_SECTION, shndx, 0);
	s->elfsym = numelfsym++;
	}

	void
	putelfsymshndx(vlong sympos, int shndx)
	{
	vlong here;

	here = cpos();
	switch(thearch.thechar) {
	case '6':
	cseek(sympos+6);
	break;
	default:
	cseek(sympos+14);
	break;
	}
	thearch.wput(shndx);
	cseek(here);
	}

	void
	asmelfsym(void)
	{
	LSym *s;
	char *name;

	// the first symbol entry is reserved
	putelfsyment(0, 0, 0, (STB_LOCAL<<4)\|STT_NOTYPE, 0, 0);

	dwarfaddelfsectionsyms();

	elfbind = STB_LOCAL;
	genasmsym(putelfsym);

	if(linkmode == LinkExternal && HEADTYPE != Hopenbsd) {
	s = linklookup(ctxt, "runtime.tlsg", 0);
	if(s->sect == nil) {
	ctxt->cursym = nil;
	diag("missing section for %s", s->name);
	errorexit();
	}
	if (strcmp(goos, "android") == 0) {
	// Android emulates runtime.tlsg as a regular variable.
	putelfsyment(putelfstr(s->name), 0, s->size, (STB_LOCAL<<4)\|STT_OBJECT, s->sect->elfsect->shnum, 0);
	} else {
	putelfsyment(putelfstr(s->name), 0, s->size, (STB_LOCAL<<4)\|STT_TLS, s->sect->elfsect->shnum, 0);
	}
	s->elfsym = numelfsym++;
	}

	elfbind = STB_GLOBAL;
	elfglobalsymndx = numelfsym;
	genasmsym(putelfsym);

	for(s=ctxt->allsym; s!=nil; s=s->allsym) {
	if(s->type != SHOSTOBJ && !(s->type == SDYNIMPORT && s->reachable))
	continue;
	if(s->type == SDYNIMPORT)
	name = s->extname;
	else
	name = s->name;
	putelfsyment(putelfstr(name), 0, 0, (STB_GLOBAL<<4)\|STT_NOTYPE, 0, 0);
	s->elfsym = numelfsym++;
	}
	}

	static void
	putplan9sym(LSym x, char s, int t, vlong addr, vlong size, int ver, LSym *go)
	{
	int i, l;

	USED(go);
	USED(ver);
	USED(size);
	USED(x);
	switch(t) {
	case 'T':
	case 'L':
	case 'D':
	case 'B':
	if(ver)
	t += 'a' - 'A';
	case 'a':
	case 'p':
	case 'f':
	case 'z':
	case 'Z':
	case 'm':
	l = 4;
	if(HEADTYPE == Hplan9 && thearch.thechar == '6' && !debug['8']) {
	lputb(addr>>32);
	l = 8;
	}
	lputb(addr);
	cput(t+0x80); /* 0x80 is variable length */

	if(t == 'z' \|\| t == 'Z') {
	cput(s[0]);
	for(i=1; s[i] != 0 \|\| s[i+1] != 0; i += 2) {
	cput(s[i]);
	cput(s[i+1]);
	}
	cput(0);
	cput(0);
	i++;
	} else {
	/* skip the '<' in filenames */
	if(t == 'f')
	s++;
	for(i=0; s[i]; i++)
	cput(s[i]);
	cput(0);
	}
	symsize += l + 1 + i + 1;
	break;
	default:
	return;
	};
	}

	void
	asmplan9sym(void)
	{
	genasmsym(putplan9sym);
	}

	static LSym *symt;

	void
	wputl(ushort w)
	{
	cput(w);
	cput(w>>8);
	}

	void
	wputb(ushort w)
	{
	cput(w>>8);
	cput(w);
	}

	void
	lputb(uint32 l)
	{
	cput(l>>24);
	cput(l>>16);
	cput(l>>8);
	cput(l);
	}

	void
	lputl(uint32 l)
	{
	cput(l);
	cput(l>>8);
	cput(l>>16);
	cput(l>>24);
	}

	void
	vputb(uint64 v)
	{
	lputb(v>>32);
	lputb(v);
	}

	void
	vputl(uint64 v)
	{
	lputl(v);
	lputl(v >> 32);
	}

	void
	symtab(void)
	{
	LSym s, symtype, symtypelink, symgostring, *symgofunc;

	dosymtype();

	// Define these so that they'll get put into the symbol table.
	// data.c:/^address will provide the actual values.
	xdefine("runtime.text", STEXT, 0);
	xdefine("runtime.etext", STEXT, 0);
	xdefine("runtime.typelink", SRODATA, 0);
	xdefine("runtime.etypelink", SRODATA, 0);
	xdefine("runtime.rodata", SRODATA, 0);
	xdefine("runtime.erodata", SRODATA, 0);
	xdefine("runtime.noptrdata", SNOPTRDATA, 0);
	xdefine("runtime.enoptrdata", SNOPTRDATA, 0);
	xdefine("runtime.data", SDATA, 0);
	xdefine("runtime.edata", SDATA, 0);
	xdefine("runtime.bss", SBSS, 0);
	xdefine("runtime.ebss", SBSS, 0);
	xdefine("runtime.noptrbss", SNOPTRBSS, 0);
	xdefine("runtime.enoptrbss", SNOPTRBSS, 0);
	xdefine("runtime.end", SBSS, 0);
	xdefine("runtime.epclntab", SRODATA, 0);
	xdefine("runtime.esymtab", SRODATA, 0);

	// garbage collection symbols
	s = linklookup(ctxt, "runtime.gcdata", 0);
	s->type = SRODATA;
	s->size = 0;
	s->reachable = 1;
	xdefine("runtime.egcdata", SRODATA, 0);

	s = linklookup(ctxt, "runtime.gcbss", 0);
	s->type = SRODATA;
	s->size = 0;
	s->reachable = 1;
	xdefine("runtime.egcbss", SRODATA, 0);

	// pseudo-symbols to mark locations of type, string, and go string data.
	s = linklookup(ctxt, "type.*", 0);
	s->type = STYPE;
	s->size = 0;
	s->reachable = 1;
	symtype = s;

	s = linklookup(ctxt, "go.string.*", 0);
	s->type = SGOSTRING;
	s->size = 0;
	s->reachable = 1;
	symgostring = s;

	s = linklookup(ctxt, "go.func.*", 0);
	s->type = SGOFUNC;
	s->size = 0;
	s->reachable = 1;
	symgofunc = s;

	symtypelink = linklookup(ctxt, "runtime.typelink", 0);

	symt = linklookup(ctxt, "runtime.symtab", 0);
	symt->type = SSYMTAB;
	symt->size = 0;
	symt->reachable = 1;

	// assign specific types so that they sort together.
	// within a type they sort by size, so the .* symbols
	// just defined above will be first.
	// hide the specific symbols.
	for(s = ctxt->allsym; s != nil; s = s->allsym) {
	if(!s->reachable \|\| s->special \|\| s->type != SRODATA)
	continue;
	if(strncmp(s->name, "type.", 5) == 0) {
	s->type = STYPE;
	s->hide = 1;
	s->outer = symtype;
	}
	if(strncmp(s->name, "go.typelink.", 12) == 0) {
	s->type = STYPELINK;
	s->hide = 1;
	s->outer = symtypelink;
	}
	if(strncmp(s->name, "go.string.", 10) == 0) {
	s->type = SGOSTRING;
	s->hide = 1;
	s->outer = symgostring;
	}
	if(strncmp(s->name, "go.func.", 8) == 0) {
	s->type = SGOFUNC;
	s->hide = 1;
	s->outer = symgofunc;
	}
	if(strncmp(s->name, "gcargs.", 7) == 0 \|\| strncmp(s->name, "gclocals.", 9) == 0 \|\| strncmp(s->name, "gclocals·", 10) == 0) {
	s->type = SGOFUNC;
	s->hide = 1;
	s->outer = symgofunc;
	s->align = 4;
	liveness += (s->size+s->align-1)&~(s->align-1);
	}
	}
	}