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ld: add NOPTRBSS for large, pointer-free uninitialized data

cc: add #pragma textflag to set it
runtime: mark mheap to go into noptr-bss.
        remove special case in garbage collector

Remove the ARM from.flag field created by CL 5687044.
The DUPOK flag was already in p->reg, so keep using that.

Otherwise test/nilptr.go creates a very large binary.
Should fix the arm build.
Diagnosed by minux.ma; replacement for CL 5690044.

R=golang-dev, minux.ma, r
CC=golang-dev
https://golang.org/cl/5686060
This commit is contained in:
Russ Cox 2012-02-21 22:08:42 -05:00
parent 9c08d65084
commit 5bcad92f07
26 changed files with 114 additions and 40 deletions

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@ -491,7 +491,6 @@ zaddr(Gen *a, int s)
Bputc(&obuf, a->type);
Bputc(&obuf, a->reg);
Bputc(&obuf, 0); // flag
Bputc(&obuf, s);
Bputc(&obuf, a->name);
switch(a->type) {

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@ -564,10 +564,9 @@ zaddr(char *bp, Adr *a, int s)
bp[0] = a->type;
bp[1] = a->reg;
bp[2] = 0; // flag
bp[3] = s;
bp[4] = a->name;
bp += 5;
bp[2] = s;
bp[3] = a->name;
bp += 4;
switch(a->type) {
default:
diag(Z, "unknown type %d in zaddr", a->type);

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@ -139,7 +139,9 @@ gclean(void)
continue;
if(s->type == types[TENUM])
continue;
textflag = s->dataflag;
gpseudo(AGLOBL, s, nodconst(s->type->width));
textflag = 0;
}
nextpc();
p->as = AEND;

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@ -27,7 +27,6 @@ struct Addr
uchar reg;
char pun;
uchar etype;
char flag;
};
#define A ((Addr*)0)

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@ -93,7 +93,6 @@ zaddr(Biobuf *b, Addr *a, int s)
default:
Bputc(b, a->type);
Bputc(b, a->reg);
Bputc(b, a->flag);
Bputc(b, s);
Bputc(b, a->name);
}

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@ -254,9 +254,9 @@ ggloblnod(Node *nam, int32 width)
p->to.type = D_CONST;
p->to.offset = width;
if(nam->readonly)
p->from.flag = RODATA;
p->reg = RODATA;
if(nam->type != T && !haspointers(nam->type))
p->from.flag |= NOPTR;
p->reg |= NOPTR;
}
void
@ -273,7 +273,7 @@ ggloblsym(Sym *s, int32 width, int dupok)
p->to.offset = width;
if(dupok)
p->reg = DUPOK;
p->from.flag |= RODATA;
p->reg |= RODATA;
}
int

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@ -75,6 +75,7 @@ enum {
ElfStrPlt,
ElfStrNoteNetbsdIdent,
ElfStrNoPtrData,
ElfStrNoPtrBss,
NElfStr
};
@ -168,6 +169,7 @@ doelf(void)
elfstr[ElfStrNoPtrData] = addstring(shstrtab, ".noptrdata");
elfstr[ElfStrData] = addstring(shstrtab, ".data");
elfstr[ElfStrBss] = addstring(shstrtab, ".bss");
elfstr[ElfStrNoPtrBss] = addstring(shstrtab, ".noptrbss");
if(HEADTYPE == Hnetbsd)
elfstr[ElfStrNoteNetbsdIdent] = addstring(shstrtab, ".note.netbsd.ident");
addstring(shstrtab, ".rodata");
@ -1847,12 +1849,14 @@ genasmsym(void (*put)(Sym*, char*, int, vlong, vlong, int, Sym*))
case STYPE:
case SSTRING:
case SGOSTRING:
case SNOPTRDATA:
if(!s->reachable)
continue;
put(s, s->name, 'D', s->value, s->size, s->version, s->gotype);
continue;
case SBSS:
case SNOPTRBSS:
if(!s->reachable)
continue;
put(s, s->name, 'B', s->value, s->size, s->version, s->gotype);

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@ -76,7 +76,6 @@ struct Adr
uchar index; // not used on arm, required by ld/go.c
char reg;
char name;
char flag;
int32 offset2; // argsize
char class;
Sym* gotype;

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@ -301,7 +301,6 @@ zaddr(Biobuf *f, Adr *a, Sym *h[])
a->type = Bgetc(f);
a->reg = Bgetc(f);
a->flag = Bgetc(f);
c = Bgetc(f);
if(c < 0 || c > NSYM){
print("sym out of range: %d\n", c);
@ -541,7 +540,7 @@ loop:
s->type = SBSS;
s->value = 0;
}
if(s->type != SBSS && s->type != SNOPTRDATA && !s->dupok) {
if(s->type != SBSS && s->type != SNOPTRBSS && !s->dupok) {
diag("redefinition: %s\n%P", s->name, p);
s->type = SBSS;
s->value = 0;
@ -550,10 +549,14 @@ loop:
s->size = p->to.offset;
if(p->reg & DUPOK)
s->dupok = 1;
if(p->from.flag & RODATA)
if(p->reg & RODATA)
s->type = SRODATA;
else if(p->from.flag & NOPTR)
s->type = SNOPTRDATA;
else if(p->reg & NOPTR) {
if(s->np > 0)
s->type = SNOPTRDATA;
else
s->type = SNOPTRBSS;
}
break;
case ADATA:

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@ -421,6 +421,8 @@ symaddr(Sym *s)
case SDATA:
case SBSS:
case SCONST:
case SNOPTRDATA:
case SNOPTRBSS:
break;
}
return v;

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@ -158,7 +158,9 @@ gclean(void)
continue;
if(s->type == types[TENUM])
continue;
textflag = s->dataflag;
gpseudo(AGLOBL, s, nodconst(s->type->width));
textflag = 0;
}
nextpc();
p->as = AEND;

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@ -96,6 +96,7 @@ enum {
ElfStrGnuVersionR,
ElfStrNoteNetbsdIdent,
ElfStrNoPtrData,
ElfStrNoPtrBss,
NElfStr
};
@ -573,6 +574,7 @@ doelf(void)
elfstr[ElfStrNoPtrData] = addstring(shstrtab, ".noptrdata");
elfstr[ElfStrData] = addstring(shstrtab, ".data");
elfstr[ElfStrBss] = addstring(shstrtab, ".bss");
elfstr[ElfStrNoPtrBss] = addstring(shstrtab, ".noptrbss");
if(HEADTYPE == Hnetbsd)
elfstr[ElfStrNoteNetbsdIdent] = addstring(shstrtab, ".note.netbsd.ident");
addstring(shstrtab, ".elfdata");
@ -1169,6 +1171,7 @@ genasmsym(void (*put)(Sym*, char*, int, vlong, vlong, int, Sym*))
case SCONST:
case SRODATA:
case SDATA:
case SNOPTRDATA:
case SELFROSECT:
case SMACHOGOT:
case STYPE:
@ -1181,6 +1184,7 @@ genasmsym(void (*put)(Sym*, char*, int, vlong, vlong, int, Sym*))
continue;
case SBSS:
case SNOPTRBSS:
if(!s->reachable)
continue;
put(s, s->name, 'B', symaddr(s), s->size, s->version, s->gotype);

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@ -555,7 +555,7 @@ loop:
s->type = SBSS;
s->size = 0;
}
if(s->type != SBSS && s->type != SNOPTRDATA && !s->dupok) {
if(s->type != SBSS && s->type != SNOPTRBSS && !s->dupok) {
diag("%s: redefinition: %s in %s",
pn, s->name, TNAME);
s->type = SBSS;
@ -567,8 +567,12 @@ loop:
s->dupok = 1;
if(p->from.scale & RODATA)
s->type = SRODATA;
else if(p->from.scale & NOPTR)
s->type = SNOPTRDATA;
else if(p->from.scale & NOPTR) {
if(s->np > 0)
s->type = SNOPTRDATA;
else
s->type = SNOPTRBSS;
}
goto loop;
case ADATA:

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@ -146,7 +146,9 @@ gclean(void)
continue;
if(s->type == types[TENUM])
continue;
textflag = s->dataflag;
gpseudo(AGLOBL, s, nodconst(s->type->width));
textflag = 0;
}
nextpc();
p->as = AEND;

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@ -92,6 +92,7 @@ enum {
ElfStrGnuVersionR,
ElfStrNoteNetbsdIdent,
ElfStrNoPtrData,
ElfStrNoPtrBss,
NElfStr
};
@ -530,6 +531,7 @@ doelf(void)
elfstr[ElfStrNoPtrData] = addstring(shstrtab, ".noptrdata");
elfstr[ElfStrData] = addstring(shstrtab, ".data");
elfstr[ElfStrBss] = addstring(shstrtab, ".bss");
elfstr[ElfStrNoPtrBss] = addstring(shstrtab, ".noptrbss");
if(HEADTYPE == Hnetbsd)
elfstr[ElfStrNoteNetbsdIdent] = addstring(shstrtab, ".note.netbsd.ident");
addstring(shstrtab, ".elfdata");
@ -1256,12 +1258,14 @@ genasmsym(void (*put)(Sym*, char*, int, vlong, vlong, int, Sym*))
case SSTRING:
case SGOSTRING:
case SWINDOWS:
case SNOPTRDATA:
if(!s->reachable)
continue;
put(s, s->name, 'D', symaddr(s), s->size, s->version, s->gotype);
continue;
case SBSS:
case SNOPTRBSS:
if(!s->reachable)
continue;
put(s, s->name, 'B', symaddr(s), s->size, s->version, s->gotype);

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@ -122,6 +122,7 @@ struct Sym
uchar sym;
uchar aused;
uchar sig;
uchar dataflag;
};
#define S ((Sym*)0)
@ -524,6 +525,7 @@ EXTERN int nterm;
EXTERN int packflg;
EXTERN int fproundflg;
EXTERN int textflag;
EXTERN int dataflag;
EXTERN int ncontin;
EXTERN int canreach;
EXTERN int warnreach;
@ -766,6 +768,7 @@ void arginit(void);
void pragvararg(void);
void pragpack(void);
void pragfpround(void);
void pragdataflag(void);
void pragtextflag(void);
void pragincomplete(void);
void pragdynimport(void);

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@ -120,6 +120,10 @@ loop:
(*f)(c, t, s);
if(s->class == CLOCAL)
s = mkstatic(s);
if(dataflag) {
s->dataflag = dataflag;
dataflag = 0;
}
firstbit = 0;
n->sym = s;
n->type = s->type;

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@ -567,19 +567,23 @@ pragfpround(void)
void
pragtextflag(void)
{
Sym *s;
textflag = 0;
s = getsym();
textflag = 7;
if(s)
textflag = atoi(s->name+1);
textflag = getnsn();
while(getnsc() != '\n')
;
if(debug['f'])
print("%4d: textflag %d\n", lineno, textflag);
}
void
pragdataflag(void)
{
dataflag = getnsn();
while(getnsc() != '\n')
;
if(debug['f'])
print("%4d: dataflag %d\n", lineno, dataflag);
}
void
pragincomplete(void)
{

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@ -74,6 +74,13 @@ pragtextflag(void)
;
}
void
pragdataflag(void)
{
while(getnsc() != '\n')
;
}
void
pragprofile(void)
{

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@ -731,6 +731,10 @@ macprag(void)
pragtextflag();
return;
}
if(s && strcmp(s->name, "dataflag") == 0) {
pragdataflag();
return;
}
if(s && strcmp(s->name, "varargck") == 0) {
pragvararg();
return;

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@ -806,8 +806,12 @@ dodata(void)
}
for(s = datap; s != nil; s = s->next) {
if(s->np > 0 && s->type == SBSS)
s->type = SDATA;
if(s->np > 0) {
if(s->type == SBSS)
s->type = SDATA;
if(s->type == SNOPTRBSS)
s->type = SNOPTRDATA;
}
if(s->np > s->size)
diag("%s: initialize bounds (%lld < %d)",
s->name, (vlong)s->size, s->np);
@ -935,11 +939,24 @@ dodata(void)
datsize += t;
}
/* bss */
/* bss, then pointer-free bss */
noptr = nil;
sect = addsection(&segdata, ".bss", 06);
sect->vaddr = datsize;
for(; s != nil; s = s->next) {
if(s->type != SBSS) {
for(; ; s = s->next) {
if((s == nil || s->type >= SNOPTRBSS) && noptr == nil) {
// finish bss, start noptrbss
datsize = rnd(datsize, 8);
sect->len = datsize - sect->vaddr;
sect = addsection(&segdata, ".noptrbss", 06);
sect->vaddr = datsize;
noptr = sect;
}
if(s == nil) {
sect->len = datsize - sect->vaddr;
break;
}
if(s->type > SNOPTRBSS) {
cursym = s;
diag("unexpected symbol type %d", s->type);
}
@ -961,7 +978,6 @@ dodata(void)
s->value = datsize;
datsize += t;
}
sect->len = datsize - sect->vaddr;
}
// assign addresses to text
@ -1004,7 +1020,7 @@ textaddress(void)
void
address(void)
{
Section *s, *text, *data, *rodata, *symtab, *pclntab, *noptr;
Section *s, *text, *data, *rodata, *symtab, *pclntab, *noptr, *bss, *noptrbss;
Sym *sym, *sub;
uvlong va;
@ -1031,6 +1047,8 @@ address(void)
segdata.fileoff = segtext.fileoff + segtext.filelen;
data = nil;
noptr = nil;
bss = nil;
noptrbss = nil;
for(s=segdata.sect; s != nil; s=s->next) {
s->vaddr = va;
va += s->len;
@ -1040,8 +1058,12 @@ address(void)
data = s;
if(strcmp(s->name, ".noptrdata") == 0)
noptr = s;
if(strcmp(s->name, ".bss") == 0)
bss = s;
if(strcmp(s->name, ".noptrbss") == 0)
noptrbss = s;
}
segdata.filelen -= data->next->len; // deduct .bss
segdata.filelen -= bss->len + noptrbss->len; // deduct .bss
text = segtext.sect;
rodata = text->next;
@ -1068,7 +1090,11 @@ address(void)
xdefine("epclntab", SRODATA, pclntab->vaddr + pclntab->len);
xdefine("noptrdata", SBSS, noptr->vaddr);
xdefine("enoptrdata", SBSS, noptr->vaddr + noptr->len);
xdefine("bss", SBSS, bss->vaddr);
xdefine("ebss", SBSS, bss->vaddr + bss->len);
xdefine("data", SBSS, data->vaddr);
xdefine("edata", SBSS, data->vaddr + data->len);
xdefine("noptrbss", SBSS, noptrbss->vaddr);
xdefine("enoptrbss", SBSS, noptrbss->vaddr + noptrbss->len);
xdefine("end", SBSS, segdata.vaddr + segdata.len);
}

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@ -49,6 +49,7 @@ enum
SMACHOGOT,
SWINDOWS,
SBSS,
SNOPTRBSS,
SXREF,
SMACHODYNSTR,

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@ -334,6 +334,10 @@ symtab(void)
xdefine("enoptrdata", SBSS, 0);
xdefine("data", SBSS, 0);
xdefine("edata", SBSS, 0);
xdefine("bss", SBSS, 0);
xdefine("ebss", SBSS, 0);
xdefine("noptrbss", SBSS, 0);
xdefine("enoptrbss", SBSS, 0);
xdefine("end", SBSS, 0);
xdefine("epclntab", SRODATA, 0);
xdefine("esymtab", SRODATA, 0);

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@ -112,7 +112,7 @@ addr(Biobuf *bp)
long off;
a.type = Bgetc(bp); /* a.type */
skip(bp,2); /* reg, flag */
skip(bp,1); /* reg */
a.sym = Bgetc(bp); /* sym index */
a.name = Bgetc(bp); /* sym type */
switch(a.type){

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@ -14,7 +14,9 @@ package runtime
#include "defs_GOOS_GOARCH.h"
#include "type.h"
#pragma dataflag 16 /* mark mheap as 'no pointers', hiding from garbage collector */
MHeap runtime·mheap;
extern MStats mstats; // defined in extern.go
extern volatile int32 runtime·MemProfileRate;

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@ -85,7 +85,7 @@ struct FinBlock
extern byte data[];
extern byte etext[];
extern byte end[];
extern byte ebss[];
static G *fing;
static FinBlock *finq; // list of finalizers that are to be executed
@ -630,10 +630,7 @@ mark(void (*scan)(byte*, int64))
FinBlock *fb;
// mark data+bss.
// skip runtime·mheap itself, which has no interesting pointers
// and is mostly zeroed and would not otherwise be paged in.
scan(data, (byte*)&runtime·mheap - data);
scan((byte*)(&runtime·mheap+1), end - (byte*)(&runtime·mheap+1));
scan(data, ebss - data);
// mark stacks
for(gp=runtime·allg; gp!=nil; gp=gp->alllink) {