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
diff --git a/src/cmd/5a/lex.c b/src/cmd/5a/lex.c
index ab7e522..4bef021 100644
--- a/src/cmd/5a/lex.c
+++ b/src/cmd/5a/lex.c
@@ -491,7 +491,6 @@
Bputc(&obuf, a->type);
Bputc(&obuf, a->reg);
- Bputc(&obuf, 0); // flag
Bputc(&obuf, s);
Bputc(&obuf, a->name);
switch(a->type) {
diff --git a/src/cmd/5c/swt.c b/src/cmd/5c/swt.c
index 124a971..7268f9a 100644
--- a/src/cmd/5c/swt.c
+++ b/src/cmd/5c/swt.c
@@ -564,10 +564,9 @@
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);
diff --git a/src/cmd/5c/txt.c b/src/cmd/5c/txt.c
index 4de8908..dea406e 100644
--- a/src/cmd/5c/txt.c
+++ b/src/cmd/5c/txt.c
@@ -139,7 +139,9 @@
continue;
if(s->type == types[TENUM])
continue;
+ textflag = s->dataflag;
gpseudo(AGLOBL, s, nodconst(s->type->width));
+ textflag = 0;
}
nextpc();
p->as = AEND;
diff --git a/src/cmd/5g/gg.h b/src/cmd/5g/gg.h
index 99b2607..7dbf3be 100644
--- a/src/cmd/5g/gg.h
+++ b/src/cmd/5g/gg.h
@@ -27,7 +27,6 @@
uchar reg;
char pun;
uchar etype;
- char flag;
};
#define A ((Addr*)0)
diff --git a/src/cmd/5g/gobj.c b/src/cmd/5g/gobj.c
index 1e0e96f..b562ba8 100644
--- a/src/cmd/5g/gobj.c
+++ b/src/cmd/5g/gobj.c
@@ -93,7 +93,6 @@
default:
Bputc(b, a->type);
Bputc(b, a->reg);
- Bputc(b, a->flag);
Bputc(b, s);
Bputc(b, a->name);
}
diff --git a/src/cmd/5g/gsubr.c b/src/cmd/5g/gsubr.c
index 387ebad..86f05fb 100644
--- a/src/cmd/5g/gsubr.c
+++ b/src/cmd/5g/gsubr.c
@@ -254,9 +254,9 @@
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 @@
p->to.offset = width;
if(dupok)
p->reg = DUPOK;
- p->from.flag |= RODATA;
+ p->reg |= RODATA;
}
int
diff --git a/src/cmd/5l/asm.c b/src/cmd/5l/asm.c
index 4a4bfe1..5edc270 100644
--- a/src/cmd/5l/asm.c
+++ b/src/cmd/5l/asm.c
@@ -75,6 +75,7 @@
ElfStrPlt,
ElfStrNoteNetbsdIdent,
ElfStrNoPtrData,
+ ElfStrNoPtrBss,
NElfStr
};
@@ -168,6 +169,7 @@
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 @@
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);
diff --git a/src/cmd/5l/l.h b/src/cmd/5l/l.h
index 4abb6f2..b1a48de 100644
--- a/src/cmd/5l/l.h
+++ b/src/cmd/5l/l.h
@@ -76,7 +76,6 @@
uchar index; // not used on arm, required by ld/go.c
char reg;
char name;
- char flag;
int32 offset2; // argsize
char class;
Sym* gotype;
diff --git a/src/cmd/5l/obj.c b/src/cmd/5l/obj.c
index 316a9a0..eb07851 100644
--- a/src/cmd/5l/obj.c
+++ b/src/cmd/5l/obj.c
@@ -301,7 +301,6 @@
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 @@
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 @@
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:
diff --git a/src/cmd/5l/span.c b/src/cmd/5l/span.c
index 2e1232a..13e1848 100644
--- a/src/cmd/5l/span.c
+++ b/src/cmd/5l/span.c
@@ -421,6 +421,8 @@
case SDATA:
case SBSS:
case SCONST:
+ case SNOPTRDATA:
+ case SNOPTRBSS:
break;
}
return v;
diff --git a/src/cmd/6c/txt.c b/src/cmd/6c/txt.c
index dd232f0..2cb8c15 100644
--- a/src/cmd/6c/txt.c
+++ b/src/cmd/6c/txt.c
@@ -158,7 +158,9 @@
continue;
if(s->type == types[TENUM])
continue;
+ textflag = s->dataflag;
gpseudo(AGLOBL, s, nodconst(s->type->width));
+ textflag = 0;
}
nextpc();
p->as = AEND;
diff --git a/src/cmd/6l/asm.c b/src/cmd/6l/asm.c
index b64a6dab..d5954ea 100644
--- a/src/cmd/6l/asm.c
+++ b/src/cmd/6l/asm.c
@@ -96,6 +96,7 @@
ElfStrGnuVersionR,
ElfStrNoteNetbsdIdent,
ElfStrNoPtrData,
+ ElfStrNoPtrBss,
NElfStr
};
@@ -573,6 +574,7 @@
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 @@
case SCONST:
case SRODATA:
case SDATA:
+ case SNOPTRDATA:
case SELFROSECT:
case SMACHOGOT:
case STYPE:
@@ -1181,6 +1184,7 @@
continue;
case SBSS:
+ case SNOPTRBSS:
if(!s->reachable)
continue;
put(s, s->name, 'B', symaddr(s), s->size, s->version, s->gotype);
diff --git a/src/cmd/6l/obj.c b/src/cmd/6l/obj.c
index 19f85f0..f441f33 100644
--- a/src/cmd/6l/obj.c
+++ b/src/cmd/6l/obj.c
@@ -555,7 +555,7 @@
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 @@
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:
diff --git a/src/cmd/8c/txt.c b/src/cmd/8c/txt.c
index 65c551e..3a08da7 100644
--- a/src/cmd/8c/txt.c
+++ b/src/cmd/8c/txt.c
@@ -146,7 +146,9 @@
continue;
if(s->type == types[TENUM])
continue;
+ textflag = s->dataflag;
gpseudo(AGLOBL, s, nodconst(s->type->width));
+ textflag = 0;
}
nextpc();
p->as = AEND;
diff --git a/src/cmd/8l/asm.c b/src/cmd/8l/asm.c
index 27881d8..2b8137f 100644
--- a/src/cmd/8l/asm.c
+++ b/src/cmd/8l/asm.c
@@ -92,6 +92,7 @@
ElfStrGnuVersionR,
ElfStrNoteNetbsdIdent,
ElfStrNoPtrData,
+ ElfStrNoPtrBss,
NElfStr
};
@@ -530,6 +531,7 @@
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 @@
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);
diff --git a/src/cmd/cc/cc.h b/src/cmd/cc/cc.h
index 566494e..f463236 100644
--- a/src/cmd/cc/cc.h
+++ b/src/cmd/cc/cc.h
@@ -122,6 +122,7 @@
uchar sym;
uchar aused;
uchar sig;
+ uchar dataflag;
};
#define S ((Sym*)0)
@@ -524,6 +525,7 @@
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 pragvararg(void);
void pragpack(void);
void pragfpround(void);
+void pragdataflag(void);
void pragtextflag(void);
void pragincomplete(void);
void pragdynimport(void);
diff --git a/src/cmd/cc/dcl.c b/src/cmd/cc/dcl.c
index d624bf2..a3ed977 100644
--- a/src/cmd/cc/dcl.c
+++ b/src/cmd/cc/dcl.c
@@ -120,6 +120,10 @@
(*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;
diff --git a/src/cmd/cc/dpchk.c b/src/cmd/cc/dpchk.c
index 084aa04..c579e20 100644
--- a/src/cmd/cc/dpchk.c
+++ b/src/cmd/cc/dpchk.c
@@ -567,13 +567,7 @@
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'])
@@ -581,6 +575,16 @@
}
void
+pragdataflag(void)
+{
+ dataflag = getnsn();
+ while(getnsc() != '\n')
+ ;
+ if(debug['f'])
+ print("%4d: dataflag %d\n", lineno, dataflag);
+}
+
+void
pragincomplete(void)
{
Sym *s;
diff --git a/src/cmd/cc/lexbody b/src/cmd/cc/lexbody
index f4cc19c..d339cf9 100644
--- a/src/cmd/cc/lexbody
+++ b/src/cmd/cc/lexbody
@@ -75,6 +75,13 @@
}
void
+pragdataflag(void)
+{
+ while(getnsc() != '\n')
+ ;
+}
+
+void
pragprofile(void)
{
while(getnsc() != '\n')
diff --git a/src/cmd/cc/macbody b/src/cmd/cc/macbody
index ed66361..874e82d 100644
--- a/src/cmd/cc/macbody
+++ b/src/cmd/cc/macbody
@@ -731,6 +731,10 @@
pragtextflag();
return;
}
+ if(s && strcmp(s->name, "dataflag") == 0) {
+ pragdataflag();
+ return;
+ }
if(s && strcmp(s->name, "varargck") == 0) {
pragvararg();
return;
diff --git a/src/cmd/ld/data.c b/src/cmd/ld/data.c
index e5e1db6..5ed8568 100644
--- a/src/cmd/ld/data.c
+++ b/src/cmd/ld/data.c
@@ -806,8 +806,12 @@
}
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 @@
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 @@
s->value = datsize;
datsize += t;
}
- sect->len = datsize - sect->vaddr;
}
// assign addresses to text
@@ -1004,7 +1020,7 @@
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 @@
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 @@
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 @@
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);
}
diff --git a/src/cmd/ld/lib.h b/src/cmd/ld/lib.h
index a66a571..f5881b5 100644
--- a/src/cmd/ld/lib.h
+++ b/src/cmd/ld/lib.h
@@ -49,6 +49,7 @@
SMACHOGOT,
SWINDOWS,
SBSS,
+ SNOPTRBSS,
SXREF,
SMACHODYNSTR,
diff --git a/src/cmd/ld/symtab.c b/src/cmd/ld/symtab.c
index d893599..6d76e9e 100644
--- a/src/cmd/ld/symtab.c
+++ b/src/cmd/ld/symtab.c
@@ -334,6 +334,10 @@
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);
diff --git a/src/libmach/5obj.c b/src/libmach/5obj.c
index a5827f5..e539362 100644
--- a/src/libmach/5obj.c
+++ b/src/libmach/5obj.c
@@ -112,7 +112,7 @@
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){
diff --git a/src/pkg/runtime/malloc.goc b/src/pkg/runtime/malloc.goc
index c9f1d67..932e3d9 100644
--- a/src/pkg/runtime/malloc.goc
+++ b/src/pkg/runtime/malloc.goc
@@ -14,7 +14,9 @@
#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;
diff --git a/src/pkg/runtime/mgc0.c b/src/pkg/runtime/mgc0.c
index 8efa7af..fd1babf 100644
--- a/src/pkg/runtime/mgc0.c
+++ b/src/pkg/runtime/mgc0.c
@@ -85,7 +85,7 @@
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 @@
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) {
