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Commit cd17a717 authored by Dmitriy Vyukov's avatar Dmitriy Vyukov
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runtime: simpler and faster GC 

Implement the design described in:
https://docs.google.com/document/d/1v4Oqa0WwHunqlb8C3ObL_uNQw3DfSY-ztoA-4wWbKcg/pub

Summary of the changes:
GC uses "2-bits per word" pointer type info embed directly into bitmap.
Scanning of stacks/data/heap is unified.
The old spans types go away.
Compiler generates "sparse" 4-bits type info for GC (directly for GC bitmap).
Linker generates "dense" 2-bits type info for data/bss (the same as stacks use).

Summary of results:
-1680 lines of code total (-1000+ in mgc0.c only)
-25% memory consumption
-3-7% binary size
-15% GC pause reduction
-7% run time reduction

LGTM=khr
R=golang-codereviews, rsc, christoph, khr
CC=golang-codereviews, rlh
https://golang.org/cl/106260045
parent 0100afbd
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Showing with 1598 additions and 2379 deletions
src/cmd/gc/go.h
View file @ cd17a717
......@@ -381,7 +381,6 @@ enum
SymExported = 1<<2, // already written out by export
SymUniq = 1<<3,
SymSiggen = 1<<4,
SymGcgen = 1<<5,
};
struct Sym
......@@ -1515,6 +1514,7 @@ void movelarge(NodeList*);
int isfat(Type*);
void linkarchinit(void);
void liveness(Node*, Prog*, Sym*, Sym*);
void twobitwalktype1(Type*, vlong*, Bvec*);
void markautoused(Prog*);
Plist* newplist(void);
Node* nodarg(Type*, int);
......
src/cmd/gc/plive.c
View file @ cd17a717
......@@ -19,8 +19,7 @@
#include "opt.h"
#include "../ld/textflag.h"
#include "../../pkg/runtime/funcdata.h"
enum { BitsPerPointer = 2 };
#include "../../pkg/runtime/mgc0.h"
enum {
UNVISITED = 0,
......@@ -1040,7 +1039,7 @@ checkptxt(Node *fn, Prog *firstp)
// and then simply copied into bv at the correct offset on future calls with
// the same type t. On https://rsc.googlecode.com/hg/testdata/slow.go, twobitwalktype1
// accounts for 40% of the 6g execution time.
static void
void
twobitwalktype1(Type *t, vlong *xoffset, Bvec *bv)
{
vlong fieldoffset;
......
src/cmd/gc/reflect.c
View file @ cd17a717
......@@ -7,6 +7,7 @@
#include "go.h"
#include "../ld/textflag.h"
#include "../../pkg/runtime/mgc0.h"
#include "../../pkg/runtime/typekind.h"
/*
* runtime interface and reflection data structures
......@@ -16,7 +17,9 @@ static NodeList* signatlist;
static Sym* dtypesym(Type*);
static Sym* weaktypesym(Type*);
static Sym* dalgsym(Type*);
static Sym* dgcsym(Type*);
static int usegcprog(Type*);
static void gengcprog(Type*, Sym**, Sym**);
static void gengcmask(Type*, uint8[16]);
static int
sigcmp(Sig *a, Sig *b)
......@@ -612,37 +615,6 @@ dextratype(Sym *sym, int off, Type *t, int ptroff)
return ot;
}
enum {
KindBool = 1,
KindInt,
KindInt8,
KindInt16,
KindInt32,
KindInt64,
KindUint,
KindUint8,
KindUint16,
KindUint32,
KindUint64,
KindUintptr,
KindFloat32,
KindFloat64,
KindComplex64,
KindComplex128,
KindArray,
KindChan,
KindFunc,
KindInterface,
KindMap,
KindPtr,
KindSlice,
KindString,
KindStruct,
KindUnsafePointer,
KindNoPointers = 1<<7,
};
static int
kinds[] =
{
......@@ -746,8 +718,9 @@ haspointers(Type *t)
static int
dcommontype(Sym *s, int ot, Type *t)
{
int i, alg, sizeofAlg;
Sym *sptr, *algsym, *zero;
int i, alg, sizeofAlg, gcprog;
Sym *sptr, *algsym, *zero, *gcprog0, *gcprog1;
uint8 gcmask[16];
static Sym *algarray;
char *p;
......@@ -809,17 +782,32 @@ dcommontype(Sym *s, int ot, Type *t)
ot = duint8(s, ot, t->align); // align
ot = duint8(s, ot, t->align); // fieldAlign
gcprog = usegcprog(t);
i = kinds[t->etype];
if(t->etype == TARRAY && t->bound < 0)
i = KindSlice;
if(!haspointers(t))
i |= KindNoPointers;
if(gcprog)
i |= KindGCProg;
ot = duint8(s, ot, i); // kind
if(alg >= 0)
ot = dsymptr(s, ot, algarray, alg*sizeofAlg);
else
ot = dsymptr(s, ot, algsym, 0);
ot = dsymptr(s, ot, dgcsym(t), 0); // gc
// gc
if(gcprog) {
gengcprog(t, &gcprog0, &gcprog1);
if(gcprog0 != S)
ot = dsymptr(s, ot, gcprog0, 0);
else
ot = duintptr(s, ot, 0);
ot = dsymptr(s, ot, gcprog1, 0);
} else {
gengcmask(t, gcmask);
for(i = 0; i < 2*widthptr; i++)
ot = duint8(s, ot, gcmask[i]);
}
p = smprint("%-uT", t);
//print("dcommontype: %s\n", p);
ot = dgostringptr(s, ot, p); // string
......@@ -1275,30 +1263,206 @@ dalgsym(Type *t)
}
static int
gcinline(Type *t)
usegcprog(Type *t)
{
switch(t->etype) {
case TARRAY:
if(t->bound == 1)
return 1;
if(t->width <= 4*widthptr)
return 1;
break;
}
vlong size, nptr;
if(!haspointers(t))
return 0;
if(t->width == BADWIDTH)
dowidth(t);
// Calculate size of the unrolled GC mask.
nptr = (t->width+widthptr-1)/widthptr;
size = nptr;
if(size%2)
size *= 2; // repeated
size = size*gcBits/8; // 4 bits per word
// Decide whether to use unrolled GC mask or GC program.
// We could use a more elaborate condition, but this seems to work well in practice.
// For small objects GC program can't give significant reduction.
// While large objects usually contain arrays; and even if it don't
// the program uses 2-bits per word while mask uses 4-bits per word,
// so the program is still smaller.
return size > 2*widthptr;
}
static int
dgcsym1(Sym *s, int ot, Type *t, vlong *off, int stack_size)
// Generates sparse GC bitmask (4 bits per word).
static void
gengcmask(Type *t, uint8 gcmask[16])
{
Type *t1;
vlong o, off2, fieldoffset, i;
Bvec *vec;
vlong xoffset, nptr, i, j;
int half, mw;
uint8 bits, *pos;
if(t->align > 0 && (*off % t->align) != 0)
fatal("dgcsym1: invalid initial alignment, %T", t);
memset(gcmask, 0, 16);
if(!haspointers(t))
return;
if(t->width == BADWIDTH)
dowidth(t);
// Generate compact mask as stacks use.
xoffset = 0;
vec = bvalloc(2*widthptr*8);
twobitwalktype1(t, &xoffset, vec);
// Unfold the mask for the GC bitmap format:
// 4 bits per word, 2 high bits encode pointer info.
pos = (uint8*)gcmask;
nptr = (t->width+widthptr-1)/widthptr;
half = 0;
mw = 0;
// If number of words is odd, repeat the mask.
// This makes simpler handling of arrays in runtime.
for(j=0; j<=(nptr%2); j++) {
for(i=0; i<nptr; i++) {
bits = bvget(vec, i*BitsPerPointer) | bvget(vec, i*BitsPerPointer+1)<<1;
// Some fake types (e.g. Hmap) has missing fileds.
// twobitwalktype1 generates BitsDead for that holes,
// replace BitsDead with BitsScalar.
if(!mw && bits == BitsDead)
bits = BitsScalar;
mw = !mw && bits == BitsMultiWord;
bits <<= 2;
if(half)
bits <<= 4;
*pos |= bits;
half = !half;
if(!half)
pos++;
}
}
}
// Helper object for generation of GC programs.
typedef struct ProgGen ProgGen;
struct ProgGen
{
Sym* s;
int32 datasize;
uint8 data[256/PointersPerByte];
vlong ot;
};
static void
proggeninit(ProgGen *g, Sym *s)
{
g->s = s;
g->datasize = 0;
g->ot = 0;
memset(g->data, 0, sizeof(g->data));
}
static void
proggenemit(ProgGen *g, uint8 v)
{
g->ot = duint8(g->s, g->ot, v);
}
// Emits insData block from g->data.
static void
proggendataflush(ProgGen *g)
{
int32 i, s;
if(g->datasize == 0)
return;
proggenemit(g, insData);
proggenemit(g, g->datasize);
s = (g->datasize + PointersPerByte - 1)/PointersPerByte;
for(i = 0; i < s; i++)
proggenemit(g, g->data[i]);
g->datasize = 0;
memset(g->data, 0, sizeof(g->data));
}
static void
proggendata(ProgGen *g, uint8 d)
{
g->data[g->datasize/PointersPerByte] |= d << ((g->datasize%PointersPerByte)*BitsPerPointer);
g->datasize++;
if(g->datasize == 255)
proggendataflush(g);
}
// Skip v bytes due to alignment, etc.
static void
proggenskip(ProgGen *g, vlong off, vlong v)
{
vlong i;
for(i = off; i < off+v; i++) {
if((i%widthptr) == 0)
proggendata(g, BitsScalar);
}
}
// Emit insArray instruction.
static void
proggenarray(ProgGen *g, vlong len)
{
int32 i;
proggendataflush(g);
proggenemit(g, insArray);
for(i = 0; i < widthptr; i++, len >>= 8)
proggenemit(g, len);
}
static void
proggenarrayend(ProgGen *g)
{
proggendataflush(g);
proggenemit(g, insArrayEnd);
}
static vlong
proggenfini(ProgGen *g)
{
proggendataflush(g);
proggenemit(g, insEnd);
return g->ot;
}
static void gengcprog1(ProgGen *g, Type *t, vlong *xoffset);
// Generates GC program for large types.
static void
gengcprog(Type *t, Sym **pgc0, Sym **pgc1)
{
Sym *gc0, *gc1;
vlong nptr, size, ot, xoffset;
ProgGen g;
nptr = (t->width+widthptr-1)/widthptr;
size = nptr;
if(size%2)
size *= 2; // repeated twice
size = size*PointersPerByte/8; // 4 bits per word
size++; // unroll flag in the beginning, used by runtime (see runtime.markallocated)
// emity space in BSS for unrolled program
*pgc0 = S;
// Don't generate it if it's too large, runtime will unroll directly into GC bitmap.
if(size <= MaxGCMask) {
gc0 = typesymprefix(".gc", t);
ggloblsym(gc0, size, DUPOK|NOPTR);
*pgc0 = gc0;
}
// program in RODATA
gc1 = typesymprefix(".gcprog", t);
proggeninit(&g, gc1);
xoffset = 0;
gengcprog1(&g, t, &xoffset);
ot = proggenfini(&g);
ggloblsym(gc1, ot, DUPOK|RODATA);
*pgc1 = gc1;
}
// Recursively walks type t and writes GC program into g.
static void
gengcprog1(ProgGen *g, Type *t, vlong *xoffset)
{
vlong fieldoffset, i, o, n;
Type *t1;
switch(t->etype) {
case TINT8:
......@@ -1317,187 +1481,71 @@ dgcsym1(Sym *s, int ot, Type *t, vlong *off, int stack_size)
case TFLOAT64:
case TCOMPLEX64:
case TCOMPLEX128:
*off += t->width;
proggenskip(g, *xoffset, t->width);
*xoffset += t->width;
break;
case TPTR32:
case TPTR64:
// NOTE: Any changes here need to be made to reflect.PtrTo as well.
if(*off % widthptr != 0)
fatal("dgcsym1: invalid alignment, %T", t);
// NOTE(rsc): Emitting GC_APTR here for *nonptrtype
// (pointer to non-pointer-containing type) means that
// we do not record 'nonptrtype' and instead tell the
// garbage collector to look up the type of the memory in
// type information stored in the heap. In effect we are telling
// the collector "we don't trust our information - use yours".
// It's not completely clear why we want to do this.
// It does have the effect that if you have a *SliceHeader and a *[]int
// pointing at the same actual slice header, *SliceHeader will not be
// used as an authoritative type for the memory, which is good:
// if the collector scanned the memory as type *SliceHeader, it would
// see no pointers inside but mark the block as scanned, preventing
// the seeing of pointers when we followed the *[]int pointer.
// Perhaps that kind of situation is the rationale.
if(!haspointers(t->type)) {
ot = duintptr(s, ot, GC_APTR);
ot = duintptr(s, ot, *off);
} else {
ot = duintptr(s, ot, GC_PTR);
ot = duintptr(s, ot, *off);
ot = dsymptr(s, ot, dgcsym(t->type), 0);
}
*off += t->width;
break;
case TUNSAFEPTR:
case TFUNC:
if(*off % widthptr != 0)
fatal("dgcsym1: invalid alignment, %T", t);
ot = duintptr(s, ot, GC_APTR);
ot = duintptr(s, ot, *off);
*off += t->width;
break;
// struct Hchan*
case TCHAN:
// NOTE: Any changes here need to be made to reflect.ChanOf as well.
if(*off % widthptr != 0)
fatal("dgcsym1: invalid alignment, %T", t);
ot = duintptr(s, ot, GC_CHAN_PTR);
ot = duintptr(s, ot, *off);
ot = dsymptr(s, ot, dtypesym(t), 0);
*off += t->width;
break;
// struct Hmap*
case TMAP:
// NOTE: Any changes here need to be made to reflect.MapOf as well.
if(*off % widthptr != 0)
fatal("dgcsym1: invalid alignment, %T", t);
ot = duintptr(s, ot, GC_PTR);
ot = duintptr(s, ot, *off);
ot = dsymptr(s, ot, dgcsym(hmap(t)), 0);
*off += t->width;
proggendata(g, BitsPointer);
*xoffset += t->width;
break;
// struct { byte *str; int32 len; }
case TSTRING:
if(*off % widthptr != 0)
fatal("dgcsym1: invalid alignment, %T", t);
ot = duintptr(s, ot, GC_STRING);
ot = duintptr(s, ot, *off);
*off += t->width;
proggendata(g, BitsMultiWord);
proggendata(g, BitsString);
*xoffset += t->width;
break;
// struct { Itab* tab; void* data; }
// struct { Type* type; void* data; } // When isnilinter(t)==true
case TINTER:
if(*off % widthptr != 0)
fatal("dgcsym1: invalid alignment, %T", t);
if(isnilinter(t)) {
ot = duintptr(s, ot, GC_EFACE);
ot = duintptr(s, ot, *off);
} else {
ot = duintptr(s, ot, GC_IFACE);
ot = duintptr(s, ot, *off);
}
*off += t->width;
proggendata(g, BitsMultiWord);
if(isnilinter(t))
proggendata(g, BitsEface);
else
proggendata(g, BitsIface);
*xoffset += t->width;
break;
case TARRAY:
if(t->bound < -1)
fatal("dgcsym1: invalid bound, %T", t);
if(t->type->width == BADWIDTH)
dowidth(t->type);
if(isslice(t)) {
// NOTE: Any changes here need to be made to reflect.SliceOf as well.
// struct { byte* array; uint32 len; uint32 cap; }
if(*off % widthptr != 0)
fatal("dgcsym1: invalid alignment, %T", t);
if(t->type->width != 0) {
ot = duintptr(s, ot, GC_SLICE);
ot = duintptr(s, ot, *off);
ot = dsymptr(s, ot, dgcsym(t->type), 0);
proggendata(g, BitsMultiWord);
proggendata(g, BitsSlice);
proggendata(g, BitsScalar);
} else {
ot = duintptr(s, ot, GC_APTR);
ot = duintptr(s, ot, *off);
}
*off += t->width;
} else {
// NOTE: Any changes here need to be made to reflect.ArrayOf as well,
// at least once ArrayOf's gc info is implemented and ArrayOf is exported.
// struct { byte* array; uint32 len; uint32 cap; }
if(t->bound < 1 || !haspointers(t->type)) {
*off += t->width;
} else if(gcinline(t)) {
for(i=0; i<t->bound; i++)
ot = dgcsym1(s, ot, t->type, off, stack_size); // recursive call of dgcsym1
} else {
if(stack_size < GC_STACK_CAPACITY) {
ot = duintptr(s, ot, GC_ARRAY_START); // a stack push during GC
ot = duintptr(s, ot, *off);
ot = duintptr(s, ot, t->bound);
ot = duintptr(s, ot, t->type->width);
off2 = 0;
ot = dgcsym1(s, ot, t->type, &off2, stack_size+1); // recursive call of dgcsym1
ot = duintptr(s, ot, GC_ARRAY_NEXT); // a stack pop during GC
t1 = t->type;
if(t1->width == 0) {
// ignore
} if(t->bound <= 1 || t->bound*t1->width < 32*widthptr) {
for(i = 0; i < t->bound; i++)
gengcprog1(g, t1, xoffset);
} else if(!haspointers(t1)) {
n = t->width;
n -= -*xoffset&(widthptr-1); // skip to next ptr boundary
proggenarray(g, (n+widthptr-1)/widthptr);
proggendata(g, BitsScalar);
proggenarrayend(g);
*xoffset -= (n+widthptr-1)/widthptr*widthptr - t->width;
} else {
ot = duintptr(s, ot, GC_REGION);
ot = duintptr(s, ot, *off);
ot = duintptr(s, ot, t->width);
ot = dsymptr(s, ot, dgcsym(t), 0);
}
*off += t->width;
proggenarray(g, t->bound);
gengcprog1(g, t1, xoffset);
*xoffset += (t->bound-1)*t1->width;
proggenarrayend(g);
}
}
break;
case TSTRUCT:
o = 0;
for(t1=t->type; t1!=T; t1=t1->down) {
for(t1 = t->type; t1 != T; t1 = t1->down) {
fieldoffset = t1->width;
*off += fieldoffset - o;
ot = dgcsym1(s, ot, t1->type, off, stack_size); // recursive call of dgcsym1
proggenskip(g, *xoffset, fieldoffset - o);
*xoffset += fieldoffset - o;
gengcprog1(g, t1->type, xoffset);
o = fieldoffset + t1->type->width;
}
*off += t->width - o;
proggenskip(g, *xoffset, t->width - o);
*xoffset += t->width - o;
break;
default:
fatal("dgcsym1: unexpected type %T", t);
fatal("gengcprog1: unexpected type, %T", t);
}
return ot;
}
static Sym*
dgcsym(Type *t)
{
int ot;
vlong off;
Sym *s;
s = typesymprefix(".gc", t);
if(s->flags & SymGcgen)
return s;
s->flags |= SymGcgen;
if(t->width == BADWIDTH)
dowidth(t);
ot = 0;
off = 0;
ot = duintptr(s, ot, t->width);
ot = dgcsym1(s, ot, t, &off, 0);
ot = duintptr(s, ot, GC_END);
ggloblsym(s, ot, DUPOK|RODATA);
if(t->align > 0)
off = rnd(off, t->align);
if(off != t->width)
fatal("dgcsym: off=%lld, size=%lld, type %T", off, t->width, t);
return s;
}
src/cmd/ld/data.c
View file @ cd17a717
......@@ -706,31 +706,165 @@ maxalign(LSym *s, int type)
return max;
}
// Helper object for building GC type programs.
typedef struct ProgGen ProgGen;
struct ProgGen
{
LSym* s;
int32 datasize;
uint8 data[256/PointersPerByte];
vlong pos;
};
static void
proggeninit(ProgGen *g, LSym *s)
{
g->s = s;
g->datasize = 0;
g->pos = 0;
memset(g->data, 0, sizeof(g->data));
}
static void
gcaddsym(LSym *gc, LSym *s, vlong off)
proggenemit(ProgGen *g, uint8 v)
{
vlong a;
LSym *gotype;
adduint8(ctxt, g->s, v);
}
// Writes insData block from g->data.
static void
proggendataflush(ProgGen *g)
{
int32 i, s;
if(s->size < PtrSize)
if(g->datasize == 0)
return;
if(strcmp(s->name, ".string") == 0)
proggenemit(g, insData);
proggenemit(g, g->datasize);
s = (g->datasize + PointersPerByte - 1)/PointersPerByte;
for(i = 0; i < s; i++)
proggenemit(g, g->data[i]);
g->datasize = 0;
memset(g->data, 0, sizeof(g->data));
}
static void
proggendata(ProgGen *g, uint8 d)
{
g->data[g->datasize/PointersPerByte] |= d << ((g->datasize%PointersPerByte)*BitsPerPointer);
g->datasize++;
if(g->datasize == 255)
proggendataflush(g);
}
// Skip v bytes due to alignment, etc.
static void
proggenskip(ProgGen *g, vlong off, vlong v)
{
vlong i;
for(i = off; i < off+v; i++) {
if((i%PtrSize) == 0)
proggendata(g, BitsScalar);
}
}
// Emit insArray instruction.
static void
proggenarray(ProgGen *g, vlong len)
{
int32 i;
proggendataflush(g);
proggenemit(g, insArray);
for(i = 0; i < PtrSize; i++, len >>= 8)
proggenemit(g, len);
}
static void
proggenarrayend(ProgGen *g)
{
proggendataflush(g);
proggenemit(g, insArrayEnd);
}
static void
proggenfini(ProgGen *g, vlong size)
{
proggenskip(g, g->pos, size - g->pos);
proggendataflush(g);
proggenemit(g, insEnd);
}
// This function generates GC pointer info for global variables.
static void
proggenaddsym(ProgGen *g, LSym *s)
{
LSym *gcprog;
uint8 *mask;
vlong i, size;
if(s->size == 0)
return;
gotype = s->gotype;
if(gotype != nil) {
//print("gcaddsym: %s %d %s\n", s->name, s->size, gotype->name);
adduintxx(ctxt, gc, GC_CALL, PtrSize);
adduintxx(ctxt, gc, off, PtrSize);
addpcrelplus(ctxt, gc, decodetype_gc(gotype), 3*PtrSize+4);
if(PtrSize == 8)
adduintxx(ctxt, gc, 0, 4);
// Skip alignment hole from the previous symbol.
proggenskip(g, g->pos, s->value - g->pos);
g->pos += s->value - g->pos;
if(s->gotype == nil && s->size >= PtrSize) {
// conservative scan
if((s->size%PtrSize) || (g->pos%PtrSize))
diag("proggenaddsym: unaligned symbol");
size = (s->size+PtrSize-1)/PtrSize*PtrSize;
if(size < 32*PtrSize) {
// Emit small symbols as data.
for(i = 0; i < size/PtrSize; i++)
proggendata(g, BitsPointer);
} else {
//print("gcaddsym: %s %d <unknown type>\n", s->name, s->size);
for(a = -off&(PtrSize-1); a+PtrSize<=s->size; a+=PtrSize) {
adduintxx(ctxt, gc, GC_APTR, PtrSize);
adduintxx(ctxt, gc, off+a, PtrSize);
// Emit large symbols as array.
proggenarray(g, size/PtrSize);
proggendata(g, BitsPointer);
proggenarrayend(g);
}
g->pos = s->value + size;
} else if(s->gotype == nil || decodetype_noptr(s->gotype) || s->size < PtrSize) {
// no scan
if(s->size < 32*PtrSize) {
// Emit small symbols as data.
// This case also handles unaligned and tiny symbols, so tread carefully.
for(i = s->value; i < s->value+s->size; i++) {
if((i%PtrSize) == 0)
proggendata(g, BitsScalar);
}
} else {
// Emit large symbols as array.
if((s->size%PtrSize) || (g->pos%PtrSize))
diag("proggenaddsym: unaligned symbol");
proggenarray(g, s->size/PtrSize);
proggendata(g, BitsScalar);
proggenarrayend(g);
}
g->pos = s->value + s->size;
} else if(decodetype_usegcprog(s->gotype)) {
// gc program, copy directly
proggendataflush(g);
gcprog = decodetype_gcprog(s->gotype);
size = decodetype_size(s->gotype);
if((size%PtrSize) || (g->pos%PtrSize))
diag("proggenaddsym: unaligned symbol");
for(i = 0; i < gcprog->np-1; i++)
proggenemit(g, gcprog->p[i]);
g->pos = s->value + size;
} else {
// gc mask, it's small so emit as data
mask = decodetype_gcmask(s->gotype);
size = decodetype_size(s->gotype);
if((size%PtrSize) || (g->pos%PtrSize))
diag("proggenaddsym: unaligned symbol");
for(i = 0; i < size; i += PtrSize)
proggendata(g, (mask[i/PtrSize/2]>>((i/PtrSize%2)*4+2))&BitsMask);
g->pos = s->value + size;
}
}
......@@ -755,19 +889,13 @@ dodata(void)
Section *sect;
Segment *segro;
LSym *s, *last, **l;
LSym *gcdata1, *gcbss1;
LSym *gcdata, *gcbss;
ProgGen gen;
if(debug['v'])
Bprint(&bso, "%5.2f dodata\n", cputime());
Bflush(&bso);
gcdata1 = linklookup(ctxt, "gcdata", 0);
gcbss1 = linklookup(ctxt, "gcbss", 0);
// size of .data and .bss section. the zero value is later replaced by the actual size of the section.
adduintxx(ctxt, gcdata1, 0, PtrSize);
adduintxx(ctxt, gcbss1, 0, PtrSize);
last = nil;
datap = nil;
......@@ -884,6 +1012,8 @@ dodata(void)
sect->vaddr = datsize;
linklookup(ctxt, "data", 0)->sect = sect;
linklookup(ctxt, "edata", 0)->sect = sect;
gcdata = linklookup(ctxt, "gcdata", 0);
proggeninit(&gen, gcdata);
for(; s != nil && s->type < SBSS; s = s->next) {
if(s->type == SINITARR) {
ctxt->cursym = s;
......@@ -893,13 +1023,11 @@ dodata(void)
s->type = SDATA;
datsize = aligndatsize(datsize, s);
s->value = datsize - sect->vaddr;
gcaddsym(gcdata1, s, datsize - sect->vaddr); // gc
proggenaddsym(&gen, s); // gc
growdatsize(&datsize, s);
}
sect->len = datsize - sect->vaddr;
adduintxx(ctxt, gcdata1, GC_END, PtrSize);
setuintxx(ctxt, gcdata1, 0, sect->len, PtrSize);
proggenfini(&gen, sect->len); // gc
/* bss */
sect = addsection(&segdata, ".bss", 06);
......@@ -908,17 +1036,17 @@ dodata(void)
sect->vaddr = datsize;
linklookup(ctxt, "bss", 0)->sect = sect;
linklookup(ctxt, "ebss", 0)->sect = sect;
gcbss = linklookup(ctxt, "gcbss", 0);
proggeninit(&gen, gcbss);
for(; s != nil && s->type < SNOPTRBSS; s = s->next) {
s->sect = sect;
datsize = aligndatsize(datsize, s);
s->value = datsize - sect->vaddr;
gcaddsym(gcbss1, s, datsize - sect->vaddr); // gc
proggenaddsym(&gen, s); // gc
growdatsize(&datsize, s);
}
sect->len = datsize - sect->vaddr;
adduintxx(ctxt, gcbss1, GC_END, PtrSize);
setuintxx(ctxt, gcbss1, 0, sect->len, PtrSize);
proggenfini(&gen, sect->len); // gc
/* pointer-free bss */
sect = addsection(&segdata, ".noptrbss", 06);
......
src/cmd/ld/decodesym.c
View file @ cd17a717
......@@ -70,14 +70,28 @@ decode_inuxi(uchar* p, int sz)
static int
commonsize(void)
{
return 7*PtrSize + 8;
return 8*PtrSize + 8;
}
// Type.commonType.kind
uint8
decodetype_kind(LSym *s)
{
return s->p[1*PtrSize + 7] & ~KindNoPointers; // 0x13 / 0x1f
return s->p[1*PtrSize + 7] & KindMask; // 0x13 / 0x1f
}
// Type.commonType.kind
uint8
decodetype_noptr(LSym *s)
{
return s->p[1*PtrSize + 7] & KindNoPointers; // 0x13 / 0x1f
}
// Type.commonType.kind
uint8
decodetype_usegcprog(LSym *s)
{
return s->p[1*PtrSize + 7] & KindGCProg; // 0x13 / 0x1f
}
// Type.commonType.size
......@@ -89,9 +103,15 @@ decodetype_size(LSym *s)
// Type.commonType.gc
LSym*
decodetype_gc(LSym *s)
decodetype_gcprog(LSym *s)
{
return decode_reloc_sym(s, 1*PtrSize + 8 + 2*PtrSize);
}
uint8*
decodetype_gcmask(LSym *s)
{
return decode_reloc_sym(s, 1*PtrSize + 8 + 1*PtrSize);
return (uint8*)(s->p + 1*PtrSize + 8 + 1*PtrSize);
}
// Type.ArrayType.elem and Type.SliceType.Elem
......
src/cmd/ld/lib.h
View file @ cd17a717
......@@ -196,9 +196,12 @@ int decodetype_funcincount(LSym *s);
LSym* decodetype_funcintype(LSym *s, int i);
int decodetype_funcoutcount(LSym *s);
LSym* decodetype_funcouttype(LSym *s, int i);
LSym* decodetype_gc(LSym *s);
LSym* decodetype_gcprog(LSym *s);
uint8* decodetype_gcmask(LSym *s);
vlong decodetype_ifacemethodcount(LSym *s);
uint8 decodetype_kind(LSym *s);
uint8 decodetype_noptr(LSym *s);
uint8 decodetype_usegcprog(LSym *s);
LSym* decodetype_mapkey(LSym *s);
LSym* decodetype_mapvalue(LSym *s);
LSym* decodetype_ptrelem(LSym *s);
......
src/pkg/reflect/type.go
View file @ cd17a717
......@@ -249,7 +249,7 @@ type rtype struct {
fieldAlign uint8 // alignment of struct field with this type
kind uint8 // enumeration for C
alg *uintptr // algorithm table (../runtime/runtime.h:/Alg)
gc unsafe.Pointer // garbage collection data
gc [2]unsafe.Pointer // garbage collection data
string *string // string form; unnecessary but undeniably useful
*uncommonType // (relatively) uncommon fields
ptrToThis *rtype // type for pointer to this type, if used in binary or has methods
......@@ -357,24 +357,6 @@ type structType struct {
fields []structField // sorted by offset
}
// NOTE: These are copied from ../runtime/mgc0.h.
// They must be kept in sync.
const (
_GC_END = iota
_GC_PTR
_GC_APTR
_GC_ARRAY_START
_GC_ARRAY_NEXT
_GC_CALL
_GC_CHAN_PTR
_GC_STRING
_GC_EFACE
_GC_IFACE
_GC_SLICE
_GC_REGION
_GC_NUM_INSTR
)
/*
* The compiler knows the exact layout of all the data structures above.
* The compiler does not know about the data structures and methods below.
......@@ -399,7 +381,8 @@ type Method struct {
// High bit says whether type has
// embedded pointers,to help garbage collector.
const (
kindMask = 0x7f
kindMask = 0x3f
kindGCProg = 0x40
kindNoPointers = 0x80
)
......@@ -1013,32 +996,6 @@ var ptrMap struct {
m map[*rtype]*ptrType
}
// garbage collection bytecode program for pointer to memory without pointers.
// See ../../cmd/gc/reflect.c:/^dgcsym1 and :/^dgcsym.
type ptrDataGC struct {
width uintptr // sizeof(ptr)
op uintptr // _GC_APTR
off uintptr // 0
end uintptr // _GC_END
}
var ptrDataGCProg = ptrDataGC{
width: unsafe.Sizeof((*byte)(nil)),
op: _GC_APTR,
off: 0,
end: _GC_END,
}
// garbage collection bytecode program for pointer to memory with pointers.
// See ../../cmd/gc/reflect.c:/^dgcsym1 and :/^dgcsym.
type ptrGC struct {
width uintptr // sizeof(ptr)
op uintptr // _GC_PTR
off uintptr // 0
elemgc unsafe.Pointer // element gc type
end uintptr // _GC_END
}
// PtrTo returns the pointer type with element t.
// For example, if t represents type Foo, PtrTo(t) represents *Foo.
func PtrTo(t Type) Type {
......@@ -1096,20 +1053,6 @@ func (t *rtype) ptrTo() *rtype {
p.zero = unsafe.Pointer(&make([]byte, p.size)[0])
p.elem = t
if t.kind&kindNoPointers != 0 {
p.gc = unsafe.Pointer(&ptrDataGCProg)
} else {
p.gc = unsafe.Pointer(&ptrGC{
width: p.size,
op: _GC_PTR,
off: 0,
elemgc: t.gc,
end: _GC_END,
})
}
// INCORRECT. Uncomment to check that TestPtrToGC fails when p.gc is wrong.
//p.gc = unsafe.Pointer(&badGC{width: p.size, end: _GC_END})
ptrMap.m[t] = p
ptrMap.Unlock()
return &p.rtype
......@@ -1414,21 +1357,6 @@ func cachePut(k cacheKey, t *rtype) Type {
return t
}
// garbage collection bytecode program for chan.
// See ../../cmd/gc/reflect.c:/^dgcsym1 and :/^dgcsym.
type chanGC struct {
width uintptr // sizeof(map)
op uintptr // _GC_CHAN_PTR
off uintptr // 0
typ *rtype // map type
end uintptr // _GC_END
}
type badGC struct {
width uintptr
end uintptr
}
// ChanOf returns the channel type with the given direction and element type.
// For example, if t represents int, ChanOf(RecvDir, t) represents <-chan int.
//
......@@ -1482,17 +1410,6 @@ func ChanOf(dir ChanDir, t Type) Type {
ch.ptrToThis = nil
ch.zero = unsafe.Pointer(&make([]byte, ch.size)[0])
ch.gc = unsafe.Pointer(&chanGC{
width: ch.size,
op: _GC_CHAN_PTR,
off: 0,
typ: &ch.rtype,
end: _GC_END,
})
// INCORRECT. Uncomment to check that TestChanOfGC fails when ch.gc is wrong.
//ch.gc = unsafe.Pointer(&badGC{width: ch.size, end: _GC_END})
return cachePut(ckey, &ch.rtype)
}
......@@ -1537,166 +1454,141 @@ func MapOf(key, elem Type) Type {
mt.key = ktyp
mt.elem = etyp
mt.bucket = bucketOf(ktyp, etyp)
mt.hmap = hMapOf(mt.bucket)
mt.uncommonType = nil
mt.ptrToThis = nil
mt.zero = unsafe.Pointer(&make([]byte, mt.size)[0])
mt.gc = unsafe.Pointer(&ptrGC{
width: unsafe.Sizeof(uintptr(0)),
op: _GC_PTR,
off: 0,
elemgc: mt.hmap.gc,
end: _GC_END,
})
// INCORRECT. Uncomment to check that TestMapOfGC and TestMapOfGCValues
// fail when mt.gc is wrong.
//mt.gc = unsafe.Pointer(&badGC{width: mt.size, end: _GC_END})
return cachePut(ckey, &mt.rtype)
}
// gcProg is a helper type for generatation of GC pointer info.
type gcProg struct {
gc []byte
size uintptr // size of type in bytes
}
func (gc *gcProg) append(v byte) {
gc.align(unsafe.Sizeof(uintptr(0)))
gc.appendWord(v)
}
// Appends t's type info to the current program.
func (gc *gcProg) appendProg(t *rtype) {
gc.align(uintptr(t.align))
if !t.pointers() {
gc.size += t.size
return
}
nptr := t.size / unsafe.Sizeof(uintptr(0))
var prog []byte
if t.kind&kindGCProg != 0 {
// Ensure that the runtime has unrolled GC program.
unsafe_New(t)
// The program is stored in t.gc[0], skip unroll flag.
prog = (*[1 << 30]byte)(unsafe.Pointer(t.gc[0]))[1:]
} else {
// The mask is embed directly in t.gc.
prog = (*[1 << 30]byte)(unsafe.Pointer(&t.gc[0]))[:]
}
for i := uintptr(0); i < nptr; i++ {
gc.appendWord(extractGCWord(prog, i))
}
}
func (gc *gcProg) appendWord(v byte) {
ptrsize := unsafe.Sizeof(uintptr(0))
if gc.size%ptrsize != 0 {
panic("reflect: unaligned GC program")
}
nptr := gc.size / ptrsize
for uintptr(len(gc.gc)) < nptr/2+1 {
gc.gc = append(gc.gc, 0x44) // BitsScalar
}
gc.gc[nptr/2] &= ^(3 << ((nptr%2)*4 + 2))
gc.gc[nptr/2] |= v << ((nptr%2)*4 + 2)
gc.size += ptrsize
}
func (gc *gcProg) finalize() unsafe.Pointer {
if gc.size == 0 {
return nil
}
ptrsize := unsafe.Sizeof(uintptr(0))
gc.align(ptrsize)
nptr := gc.size / ptrsize
for uintptr(len(gc.gc)) < nptr/2+1 {
gc.gc = append(gc.gc, 0x44) // BitsScalar
}
// If number of words is odd, repeat the mask twice.
// Compiler does the same.
if nptr%2 != 0 {
for i := uintptr(0); i < nptr; i++ {
gc.appendWord(extractGCWord(gc.gc, i))
}
}
gc.gc = append([]byte{1}, gc.gc...) // prepend unroll flag
return unsafe.Pointer(&gc.gc[0])
}
func extractGCWord(gc []byte, i uintptr) byte {
return (gc[i/2] >> ((i%2)*4 + 2)) & 3
}
func (gc *gcProg) align(a uintptr) {
gc.size = align(gc.size, a)
}
const (
bitsScalar = 1
bitsPointer = 2
)
// Make sure these routines stay in sync with ../../pkg/runtime/hashmap.c!
// These types exist only for GC, so we only fill out GC relevant info.
// Currently, that's just size and the GC program. We also fill in string
// for possible debugging use.
const (
_BUCKETSIZE = 8
_MAXKEYSIZE = 128
_MAXVALSIZE = 128
bucketSize = 8
maxKeySize = 128
maxValSize = 128
)
func bucketOf(ktyp, etyp *rtype) *rtype {
if ktyp.size > _MAXKEYSIZE {
if ktyp.size > maxKeySize {
ktyp = PtrTo(ktyp).(*rtype)
}
if etyp.size > _MAXVALSIZE {
if etyp.size > maxValSize {
etyp = PtrTo(etyp).(*rtype)
}
ptrsize := unsafe.Sizeof(uintptr(0))
gc := make([]uintptr, 1) // first entry is size, filled in at the end
offset := _BUCKETSIZE * unsafe.Sizeof(uint8(0)) // topbits
gc = append(gc, _GC_PTR, offset, 0 /*self pointer set below*/) // overflow
offset += ptrsize
var gc gcProg
// topbits
for i := 0; i < int(bucketSize*unsafe.Sizeof(uint8(0))/ptrsize); i++ {
gc.append(bitsScalar)
}
gc.append(bitsPointer) // overflow
if runtime.GOARCH == "amd64p32" {
offset += 4
gc.append(bitsScalar)
}
// keys
if ktyp.kind&kindNoPointers == 0 {
gc = append(gc, _GC_ARRAY_START, offset, _BUCKETSIZE, ktyp.size)
gc = appendGCProgram(gc, ktyp)
gc = append(gc, _GC_ARRAY_NEXT)
for i := 0; i < bucketSize; i++ {
gc.appendProg(ktyp)
}
offset += _BUCKETSIZE * ktyp.size
// values
if etyp.kind&kindNoPointers == 0 {
gc = append(gc, _GC_ARRAY_START, offset, _BUCKETSIZE, etyp.size)
gc = appendGCProgram(gc, etyp)
gc = append(gc, _GC_ARRAY_NEXT)
for i := 0; i < bucketSize; i++ {
gc.appendProg(etyp)
}
offset += _BUCKETSIZE * etyp.size
gc = append(gc, _GC_END)
gc[0] = offset
gc[3] = uintptr(unsafe.Pointer(&gc[0])) // set self pointer
b := new(rtype)
b.size = offset
b.gc = unsafe.Pointer(&gc[0])
b.size = gc.size
b.gc[0] = gc.finalize()
b.kind |= kindGCProg
s := "bucket(" + *ktyp.string + "," + *etyp.string + ")"
b.string = &s
return b
}
// Take the GC program for "t" and append it to the GC program "gc".
func appendGCProgram(gc []uintptr, t *rtype) []uintptr {
p := t.gc
p = unsafe.Pointer(uintptr(p) + unsafe.Sizeof(uintptr(0))) // skip size
loop:
for {
var argcnt int
switch *(*uintptr)(p) {
case _GC_END:
// Note: _GC_END not included in append
break loop
case _GC_ARRAY_NEXT:
argcnt = 0
case _GC_APTR, _GC_STRING, _GC_EFACE, _GC_IFACE:
argcnt = 1
case _GC_PTR, _GC_CALL, _GC_CHAN_PTR, _GC_SLICE:
argcnt = 2
case _GC_ARRAY_START, _GC_REGION:
argcnt = 3
default:
panic("unknown GC program op for " + *t.string + ": " + strconv.FormatUint(*(*uint64)(p), 10))
}
for i := 0; i < argcnt+1; i++ {
gc = append(gc, *(*uintptr)(p))
p = unsafe.Pointer(uintptr(p) + unsafe.Sizeof(uintptr(0)))
}
}
return gc
}
func hMapOf(bucket *rtype) *rtype {
ptrsize := unsafe.Sizeof(uintptr(0))
// make gc program & compute hmap size
gc := make([]uintptr, 1) // first entry is size, filled in at the end
offset := unsafe.Sizeof(uint(0)) // count
offset += unsafe.Sizeof(uint32(0)) // flags
offset += unsafe.Sizeof(uint32(0)) // hash0
offset += unsafe.Sizeof(uint8(0)) // B
offset += unsafe.Sizeof(uint8(0)) // keysize
offset += unsafe.Sizeof(uint8(0)) // valuesize
offset = (offset + 1) / 2 * 2
offset += unsafe.Sizeof(uint16(0)) // bucketsize
offset = (offset + ptrsize - 1) / ptrsize * ptrsize
gc = append(gc, _GC_PTR, offset, uintptr(bucket.gc)) // buckets
offset += ptrsize
gc = append(gc, _GC_PTR, offset, uintptr(bucket.gc)) // oldbuckets
offset += ptrsize
offset += ptrsize // nevacuate
gc = append(gc, _GC_END)
gc[0] = offset
h := new(rtype)
h.size = offset
h.gc = unsafe.Pointer(&gc[0])
s := "hmap(" + *bucket.string + ")"
h.string = &s
return h
}
// garbage collection bytecode program for slice of non-zero-length values.
// See ../../cmd/gc/reflect.c:/^dgcsym1 and :/^dgcsym.
type sliceGC struct {
width uintptr // sizeof(slice)
op uintptr // _GC_SLICE
off uintptr // 0
elemgc unsafe.Pointer // element gc program
end uintptr // _GC_END
}
// garbage collection bytecode program for slice of zero-length values.
// See ../../cmd/gc/reflect.c:/^dgcsym1 and :/^dgcsym.
type sliceEmptyGC struct {
width uintptr // sizeof(slice)
op uintptr // _GC_APTR
off uintptr // 0
end uintptr // _GC_END
}
var sliceEmptyGCProg = sliceEmptyGC{
width: unsafe.Sizeof([]byte(nil)),
op: _GC_APTR,
off: 0,
end: _GC_END,
}
// SliceOf returns the slice type with element type t.
// For example, if t represents int, SliceOf(t) represents []int.
func SliceOf(t Type) Type {
......@@ -1729,21 +1621,6 @@ func SliceOf(t Type) Type {
slice.ptrToThis = nil
slice.zero = unsafe.Pointer(&make([]byte, slice.size)[0])
if typ.size == 0 {
slice.gc = unsafe.Pointer(&sliceEmptyGCProg)
} else {
slice.gc = unsafe.Pointer(&sliceGC{
width: slice.size,
op: _GC_SLICE,
off: 0,
elemgc: typ.gc,
end: _GC_END,
})
}
// INCORRECT. Uncomment to check that TestSliceOfOfGC fails when slice.gc is wrong.
//slice.gc = unsafe.Pointer(&badGC{width: slice.size, end: _GC_END})
return cachePut(ckey, &slice.rtype)
}
......@@ -1861,49 +1738,41 @@ func funcLayout(t *rtype, rcvr *rtype) (frametype *rtype, argSize, retOffset uin
tt := (*funcType)(unsafe.Pointer(t))
// compute gc program for arguments
gc := make([]uintptr, 1) // first entry is size, filled in at the end
offset := uintptr(0)
var gc gcProg
if rcvr != nil {
// Reflect uses the "interface" calling convention for
// methods, where receivers take one word of argument
// space no matter how big they actually are.
if rcvr.size > ptrSize {
// we pass a pointer to the receiver.
gc = append(gc, _GC_PTR, offset, uintptr(rcvr.gc))
gc.append(bitsPointer)
} else if rcvr.pointers() {
// rcvr is a one-word pointer object. Its gc program
// is just what we need here.
gc = appendGCProgram(gc, rcvr)
gc.append(bitsPointer)
} else {
gc.append(bitsScalar)
}
offset += ptrSize
}
for _, arg := range tt.in {
offset = align(offset, uintptr(arg.align))
if arg.pointers() {
gc = append(gc, _GC_REGION, offset, arg.size, uintptr(arg.gc))
gc.appendProg(arg)
}
offset += arg.size
}
argSize = offset
argSize = gc.size
if runtime.GOARCH == "amd64p32" {
offset = align(offset, 8)
gc.align(8)
}
offset = align(offset, ptrSize)
retOffset = offset
gc.align(ptrSize)
retOffset = gc.size
for _, res := range tt.out {
offset = align(offset, uintptr(res.align))
if res.pointers() {
gc = append(gc, _GC_REGION, offset, res.size, uintptr(res.gc))
}
offset += res.size
gc.appendProg(res)
}
gc = append(gc, _GC_END)
gc[0] = offset
gc.align(ptrSize)
// build dummy rtype holding gc program
x := new(rtype)
x.size = offset
x.gc = unsafe.Pointer(&gc[0])
x.size = gc.size
x.gc[0] = gc.finalize()
x.kind |= kindGCProg
var s string
if rcvr != nil {
s = "methodargs(" + *rcvr.string + ")(" + *t.string + ")"
......
src/pkg/runtime/chan.goc
View file @ cd17a717
......@@ -37,7 +37,7 @@ makechan(ChanType *t, int64 hint)
runtime·panicstring("makechan: size out of range");
// allocate memory in one call
c = (Hchan*)runtime·mallocgc(sizeof(*c) + hint*elem->size, (uintptr)t | TypeInfo_Chan, 0);
c = (Hchan*)runtime·mallocgc(sizeof(*c) + hint*elem->size, nil, 0);
c->elemsize = elem->size;
c->elemtype = elem;
c->dataqsiz = hint;
......
src/pkg/runtime/export_test.go
View file @ cd17a717
......@@ -62,6 +62,9 @@ func ParForIters(desc *ParFor, tid uint32) (uint32, uint32) {
return uint32(begin), uint32(end)
}
//go:noescape
func GCMask(x interface{}) []byte
func testSchedLocalQueue()
func testSchedLocalQueueSteal()
......
src/pkg/runtime/gc_test.go
View file @ cd17a717
......@@ -10,6 +10,7 @@ import (
"runtime/debug"
"testing"
"time"
"unsafe"
)
func TestGcSys(t *testing.T) {
......@@ -165,6 +166,29 @@ func TestGcLastTime(t *testing.T) {
}
}
var hugeSink interface{}
func TestHugeGCInfo(t *testing.T) {
// The test ensures that compiler can chew these huge types even on weakest machines.
// The types are not allocated at runtime.
if hugeSink != nil {
// 400MB on 32 bots, 4TB on 64-bits.
const n = (400 << 20) + (unsafe.Sizeof(uintptr(0))-4)<<40
hugeSink = new([n]*byte)
hugeSink = new([n]uintptr)
hugeSink = new(struct {
x float64
y [n]*byte
z []string
})
hugeSink = new(struct {
x float64
y [n]uintptr
z []string
})
}
}
func BenchmarkSetTypeNoPtr1(b *testing.B) {
type NoPtr1 struct {
p uintptr
......
src/pkg/runtime/gcinfo_test.go 0 → 100644
View file @ cd17a717
// Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package runtime_test
import (
"bytes"
"runtime"
"testing"
)
// TestGCInfo tests that various objects in heap, data and bss receive correct GC pointer type info.
func TestGCInfo(t *testing.T) {
verifyGCInfo(t, "bss ScalarPtr", &bssScalarPtr, infoScalarPtr)
verifyGCInfo(t, "bss PtrScalar", &bssPtrScalar, infoPtrScalar)
verifyGCInfo(t, "bss Complex", &bssComplex, infoComplex())
verifyGCInfo(t, "bss string", &bssString, infoString)
verifyGCInfo(t, "bss eface", &bssEface, infoEface)
verifyGCInfo(t, "data ScalarPtr", &dataScalarPtr, infoScalarPtr)
verifyGCInfo(t, "data PtrScalar", &dataPtrScalar, infoPtrScalar)
verifyGCInfo(t, "data Complex", &dataComplex, infoComplex())
verifyGCInfo(t, "data string", &dataString, infoString)
verifyGCInfo(t, "data eface", &dataEface, infoEface)
for i := 0; i < 3; i++ {
verifyGCInfo(t, "heap ScalarPtr", escape(new(ScalarPtr)), infoScalarPtr)
verifyGCInfo(t, "heap PtrScalar", escape(new(PtrScalar)), infoPtrScalar)
verifyGCInfo(t, "heap Complex", escape(new(Complex)), infoComplex())
verifyGCInfo(t, "heap string", escape(new(string)), infoString)
verifyGCInfo(t, "heap eface", escape(new(interface{})), infoEface)
}
}
func verifyGCInfo(t *testing.T, name string, p interface{}, mask0 []byte) {
mask := runtime.GCMask(p)
if len(mask) > len(mask0) {
mask0 = append(mask0, BitsDead)
mask = mask[:len(mask0)]
}
if bytes.Compare(mask, mask0) != 0 {
t.Errorf("bad GC program for %v:\nwant %+v\ngot %+v", name, mask0, mask)
return
}
}
var gcinfoSink interface{}
func escape(p interface{}) interface{} {
gcinfoSink = p
return p
}
const (
BitsDead = iota
BitsScalar
BitsPointer
BitsMultiWord
)
const (
BitsString = iota
BitsSlice
BitsIface
BitsEface
)
type ScalarPtr struct {
q int
w *int
e int
r *int
t int
y *int
}
var infoScalarPtr = []byte{BitsScalar, BitsPointer, BitsScalar, BitsPointer, BitsScalar, BitsPointer}
type PtrScalar struct {
q *int
w int
e *int
r int
t *int
y int
}
var infoPtrScalar = []byte{BitsPointer, BitsScalar, BitsPointer, BitsScalar, BitsPointer, BitsScalar}
type Complex struct {
q *int
w byte
e [17]byte
r []byte
t int
y uint16
u uint64
i string
}
func infoComplex() []byte {
switch runtime.GOARCH {
case "386", "arm":
return []byte{
BitsPointer, BitsScalar, BitsScalar, BitsScalar,
BitsScalar, BitsScalar, BitsMultiWord, BitsSlice,
BitsScalar, BitsScalar, BitsScalar, BitsScalar,
BitsScalar, BitsMultiWord, BitsString,
}
case "amd64":
return []byte{
BitsPointer, BitsScalar, BitsScalar, BitsScalar,
BitsMultiWord, BitsSlice, BitsScalar, BitsScalar,
BitsScalar, BitsScalar, BitsMultiWord, BitsString,
}
case "amd64p32":
return []byte{
BitsPointer, BitsScalar, BitsScalar, BitsScalar,
BitsScalar, BitsScalar, BitsMultiWord, BitsSlice,
BitsScalar, BitsScalar, BitsScalar, BitsScalar,
BitsScalar, BitsScalar, BitsMultiWord, BitsString,
}
default:
panic("unknown arch")
}
}
var (
// BSS
bssScalarPtr ScalarPtr
bssPtrScalar PtrScalar
bssComplex Complex
bssString string
bssEface interface{}
// DATA
dataScalarPtr = ScalarPtr{q: 1}
dataPtrScalar = PtrScalar{w: 1}
dataComplex = Complex{w: 1}
dataString = "foo"
dataEface interface{} = 42
infoString = []byte{BitsMultiWord, BitsString}
infoEface = []byte{BitsMultiWord, BitsEface}
)
src/pkg/runtime/heapdump.c
View file @ cd17a717
......@@ -52,17 +52,17 @@ enum {
TagPanic = 15,
TagMemProf = 16,
TagAllocSample = 17,
TypeInfo_Conservative = 127,
};
static uintptr* playgcprog(uintptr offset, uintptr *prog, void (*callback)(void*,uintptr,uintptr), void *arg);
static void dumpfields(uintptr *prog);
static void dumpefacetypes(void *obj, uintptr size, Type *type, uintptr kind);
static void dumpfields(BitVector bv);
static void dumpbvtypes(BitVector *bv, byte *base);
static BitVector makeheapobjbv(byte *p, uintptr size);
// fd to write the dump to.
static uintptr dumpfd;
static byte *tmpbuf;
static uintptr tmpbufsize;
// buffer of pending write data
enum {
......@@ -199,34 +199,18 @@ dumptype(Type *t)
write(t->x->name->str, t->x->name->len);
}
dumpbool(t->size > PtrSize || (t->kind & KindNoPointers) == 0);
dumpfields((uintptr*)t->gc + 1);
}
// returns true if object is scannable
static bool
scannable(byte *obj)
{
uintptr *b, off, shift;
off = (uintptr*)obj - (uintptr*)runtime·mheap.arena_start; // word offset
b = (uintptr*)runtime·mheap.arena_start - off/wordsPerBitmapWord - 1;
shift = off % wordsPerBitmapWord;
return ((*b >> shift) & bitScan) != 0;
dumpfields((BitVector){0, nil});
}
// dump an object
static void
dumpobj(byte *obj, uintptr size, Type *type, uintptr kind)
dumpobj(byte *obj, uintptr size, BitVector bv)
{
if(type != nil) {
dumptype(type);
dumpefacetypes(obj, size, type, kind);
}
dumpbvtypes(&bv, obj);
dumpint(TagObject);
dumpint((uintptr)obj);
dumpint((uintptr)type);
dumpint(kind);
dumpint(0); // Type*
dumpint(0); // kind
dumpmemrange(obj, size);
}
......@@ -513,33 +497,19 @@ dumproots(void)
dumpint(TagData);
dumpint((uintptr)data);
dumpmemrange(data, edata - data);
dumpfields((uintptr*)gcdata + 1);
dumpfields((BitVector){(edata - data)*8, (uint32*)gcdata});
// bss segment
dumpint(TagBss);
dumpint((uintptr)bss);
dumpmemrange(bss, ebss - bss);
dumpfields((uintptr*)gcbss + 1);
dumpfields((BitVector){(ebss - bss)*8, (uint32*)gcbss});
// MSpan.types
allspans = runtime·mheap.allspans;
for(spanidx=0; spanidx<runtime·mheap.nspan; spanidx++) {
s = allspans[spanidx];
if(s->state == MSpanInUse) {
// The garbage collector ignores type pointers stored in MSpan.types:
// - Compiler-generated types are stored outside of heap.
// - The reflect package has runtime-generated types cached in its data structures.
// The garbage collector relies on finding the references via that cache.
switch(s->types.compression) {
case MTypes_Empty:
case MTypes_Single:
break;
case MTypes_Words:
case MTypes_Bytes:
dumpotherroot("runtime type info", (byte*)s->types.data);
break;
}
// Finalizers
for(sp = s->specials; sp != nil; sp = sp->next) {
if(sp->kind != KindSpecialFinalizer)
......@@ -555,18 +525,12 @@ dumproots(void)
runtime·iterate_finq(finq_callback);
}
// Bit vector of free marks.
// Needs to be as big as the largest number of objects per span.
static byte free[PageSize/8];
static void
dumpobjs(void)
{
uintptr i, j, size, n, off, shift, *bitp, bits, ti, kind;
uintptr i, j, size, n, off, shift, *bitp, bits;
MSpan *s;
MLink *l;
byte *p;
Type *t;
for(i = 0; i < runtime·mheap.nspan; i++) {
s = runtime·mheap.allspans[i];
......@@ -575,36 +539,16 @@ dumpobjs(void)
p = (byte*)(s->start << PageShift);
size = s->elemsize;
n = (s->npages << PageShift) / size;
if(n > PageSize/8)
runtime·throw("free array doesn't have enough entries");
for(l = s->freelist; l != nil; l = l->next) {
free[((byte*)l - p) / size] = true;
}
for(j = 0; j < n; j++, p += size) {
if(free[j]) {
free[j] = false;
continue;
}
off = (uintptr*)p - (uintptr*)runtime·mheap.arena_start;
bitp = (uintptr*)runtime·mheap.arena_start - off/wordsPerBitmapWord - 1;
shift = off % wordsPerBitmapWord;
bits = *bitp >> shift;
shift = (off % wordsPerBitmapWord) * gcBits;
bits = (*bitp >> shift) & bitMask;
// Skip FlagNoGC allocations (stacks)
if((bits & bitAllocated) == 0)
if(bits != bitAllocated)
continue;
// extract type and kind
ti = runtime·gettype(p);
t = (Type*)(ti & ~(uintptr)(PtrSize-1));
kind = ti & (PtrSize-1);
// dump it
if(kind == TypeInfo_Chan)
t = ((ChanType*)t)->elem; // use element type for chan encoding
if(t == nil && scannable(p))
kind = TypeInfo_Conservative; // special kind for conservatively scanned objects
dumpobj(p, size, t, kind);
dumpobj(p, size, makeheapobjbv(p, size));
}
}
}
......@@ -621,7 +565,6 @@ dumpparams(void)
else
dumpbool(true); // big-endian ptrs
dumpint(PtrSize);
dumpint(runtime·Hchansize);
dumpint((uintptr)runtime·mheap.arena_start);
dumpint((uintptr)runtime·mheap.arena_used);
dumpint(thechar);
......@@ -819,6 +762,11 @@ runtime∕debug·WriteHeapDump(uintptr fd)
// Reset dump file.
dumpfd = 0;
if(tmpbuf != nil) {
runtime·SysFree(tmpbuf, tmpbufsize, &mstats.other_sys);
tmpbuf = nil;
tmpbufsize = 0;
}
// Start up the world again.
g->m->gcing = 0;
......@@ -827,132 +775,17 @@ runtime∕debug·WriteHeapDump(uintptr fd)
g->m->locks--;
}
// Runs the specified gc program. Calls the callback for every
// pointer-like field specified by the program and passes to the
// callback the kind and offset of that field within the object.
// offset is the offset in the object of the start of the program.
// Returns a pointer to the opcode that ended the gc program (either
// GC_END or GC_ARRAY_NEXT).
static uintptr*
playgcprog(uintptr offset, uintptr *prog, void (*callback)(void*,uintptr,uintptr), void *arg)
{
uintptr len, elemsize, i, *end;
for(;;) {
switch(prog[0]) {
case GC_END:
return prog;
case GC_PTR:
callback(arg, FieldKindPtr, offset + prog[1]);
prog += 3;
break;
case GC_APTR:
callback(arg, FieldKindPtr, offset + prog[1]);
prog += 2;
break;
case GC_ARRAY_START:
len = prog[2];
elemsize = prog[3];
end = nil;
for(i = 0; i < len; i++) {
end = playgcprog(offset + prog[1] + i * elemsize, prog + 4, callback, arg);
if(end[0] != GC_ARRAY_NEXT)
runtime·throw("GC_ARRAY_START did not have matching GC_ARRAY_NEXT");
}
prog = end + 1;
break;
case GC_ARRAY_NEXT:
return prog;
case GC_CALL:
playgcprog(offset + prog[1], (uintptr*)((byte*)prog + *(int32*)&prog[2]), callback, arg);
prog += 3;
break;
case GC_CHAN_PTR:
callback(arg, FieldKindPtr, offset + prog[1]);
prog += 3;
break;
case GC_STRING:
callback(arg, FieldKindString, offset + prog[1]);
prog += 2;
break;
case GC_EFACE:
callback(arg, FieldKindEface, offset + prog[1]);
prog += 2;
break;
case GC_IFACE:
callback(arg, FieldKindIface, offset + prog[1]);
prog += 2;
break;
case GC_SLICE:
callback(arg, FieldKindSlice, offset + prog[1]);
prog += 3;
break;
case GC_REGION:
playgcprog(offset + prog[1], (uintptr*)prog[3] + 1, callback, arg);
prog += 4;
break;
default:
runtime·printf("%D\n", (uint64)prog[0]);
runtime·throw("bad gc op");
}
}
}
static void
dump_callback(void *p, uintptr kind, uintptr offset)
{
USED(&p);
dumpint(kind);
dumpint(offset);
}
// dumpint() the kind & offset of each field in an object.
static void
dumpfields(uintptr *prog)
dumpfields(BitVector bv)
{
playgcprog(0, prog, dump_callback, nil);
dumpbv(&bv, 0);
dumpint(FieldKindEol);
}
static void
dumpeface_callback(void *p, uintptr kind, uintptr offset)
{
Eface *e;
if(kind != FieldKindEface)
return;
e = (Eface*)((byte*)p + offset);
dumptype(e->type);
}
// The heap dump reader needs to be able to disambiguate
// Eface entries. So it needs to know every type that might
// appear in such an entry. The following two routines accomplish
// that.
// Dump all the types that appear in the type field of
// any Eface contained in obj.
static void
dumpefacetypes(void *obj, uintptr size, Type *type, uintptr kind)
{
uintptr i;
switch(kind) {
case TypeInfo_SingleObject:
playgcprog(0, (uintptr*)type->gc + 1, dumpeface_callback, obj);
break;
case TypeInfo_Array:
for(i = 0; i <= size - type->size; i += type->size)
playgcprog(i, (uintptr*)type->gc + 1, dumpeface_callback, obj);
break;
case TypeInfo_Chan:
if(type->size == 0) // channels may have zero-sized objects in them
break;
for(i = runtime·Hchansize; i <= size - type->size; i += type->size)
playgcprog(i, (uintptr*)type->gc + 1, dumpeface_callback, obj);
break;
}
}
// appear in such an entry. The following routine accomplishes that.
// Dump all the types that appear in the type field of
// any Eface described by this bit vector.
......@@ -979,3 +812,36 @@ dumpbvtypes(BitVector *bv, byte *base)
}
}
}
static BitVector
makeheapobjbv(byte *p, uintptr size)
{
uintptr off, shift, *bitp, bits, nptr, i;
bool mw;
// Extend the temp buffer if necessary.
nptr = size/PtrSize;
if(tmpbufsize < nptr*BitsPerPointer/8+1) {
if(tmpbuf != nil)
runtime·SysFree(tmpbuf, tmpbufsize, &mstats.other_sys);
tmpbufsize = nptr*BitsPerPointer/8+1;
tmpbuf = runtime·SysAlloc(tmpbufsize, &mstats.other_sys);
if(tmpbuf == nil)
runtime·throw("heapdump: out of memory");
}
// Copy and compact the bitmap.
mw = false;
for(i = 0; i < nptr; i++) {
off = (uintptr*)(p + i*PtrSize) - (uintptr*)runtime·mheap.arena_start;
bitp = (uintptr*)runtime·mheap.arena_start - off/wordsPerBitmapWord - 1;
shift = (off % wordsPerBitmapWord) * gcBits;
bits = (*bitp >> (shift + 2)) & 3;
if(!mw && bits == BitsDead)
break; // end of heap object
mw = !mw && bits == BitsMultiWord;
tmpbuf[i*BitsPerPointer/8] &= ~(3<<((i*BitsPerPointer)%8));
tmpbuf[i*BitsPerPointer/8] |= bits<<((i*BitsPerPointer)%8);
}
return (BitVector){i*BitsPerPointer, (uint32*)tmpbuf};
}
src/pkg/runtime/malloc.goc
View file @ cd17a717
......@@ -22,8 +22,6 @@ MHeap runtime·mheap;
#pragma dataflag NOPTR
MStats mstats;
int32 runtime·checking;
extern MStats mstats; // defined in zruntime_def_$GOOS_$GOARCH.go
extern volatile intgo runtime·MemProfileRate;
......@@ -37,10 +35,10 @@ static void settype(MSpan *s, void *v, uintptr typ);
// Large objects (> 32 kB) are allocated straight from the heap.
// If the block will be freed with runtime·free(), typ must be 0.
void*
runtime·mallocgc(uintptr size, uintptr typ, uint32 flag)
runtime·mallocgc(uintptr size, Type *typ, uint32 flag)
{
int32 sizeclass;
uintptr tinysize, size1;
uintptr tinysize, size0, size1;
intgo rate;
MCache *c;
MSpan *s;
......@@ -60,9 +58,7 @@ runtime·mallocgc(uintptr size, uintptr typ, uint32 flag)
g->m->locks++;
g->m->mallocing = 1;
if(DebugTypeAtBlockEnd)
size += sizeof(uintptr);
size0 = size;
c = g->m->mcache;
if(!runtime·debug.efence && size <= MaxSmallSize) {
if((flag&(FlagNoScan|FlagNoGC)) == FlagNoScan && size < TinySize) {
......@@ -170,19 +166,10 @@ runtime·mallocgc(uintptr size, uintptr typ, uint32 flag)
v = (void*)(s->start << PageShift);
}
if(flag & FlagNoGC)
runtime·marknogc(v);
else if(!(flag & FlagNoScan))
runtime·markscan(v);
if(DebugTypeAtBlockEnd)
*(uintptr*)((uintptr)v+size-sizeof(uintptr)) = typ;
if(!(flag & FlagNoGC))
runtime·markallocated(v, size, size0, typ, !(flag&FlagNoScan));
g->m->mallocing = 0;
// TODO: save type even if FlagNoScan? Potentially expensive but might help
// heap profiling/tracing.
if(UseSpanType && !(flag & FlagNoScan) && typ != 0)
settype(s, v, typ);
if(raceenabled)
runtime·racemalloc(v, size);
......@@ -261,7 +248,7 @@ profilealloc(void *v, uintptr size)
void*
runtime·malloc(uintptr size)
{
return runtime·mallocgc(size, 0, FlagNoInvokeGC);
return runtime·mallocgc(size, nil, FlagNoInvokeGC);
}
// Free the object whose base pointer is v.
......@@ -311,7 +298,7 @@ runtime·free(void *v)
// Must mark v freed before calling unmarkspan and MHeap_Free:
// they might coalesce v into other spans and change the bitmap further.
runtime·markfreed(v);
runtime·unmarkspan(v, 1<<PageShift);
runtime·unmarkspan(v, s->npages<<PageShift);
// NOTE(rsc,dvyukov): The original implementation of efence
// in CL 22060046 used SysFree instead of SysFault, so that
// the operating system would eventually give the memory
......@@ -326,9 +313,10 @@ runtime·free(void *v)
// have mysterious crashes due to confused memory reuse.
// It should be possible to switch back to SysFree if we also
// implement and then call some kind of MHeap_DeleteSpan.
if(runtime·debug.efence)
if(runtime·debug.efence) {
s->limit = nil; // prevent mlookup from finding this span
runtime·SysFault((void*)(s->start<<PageShift), size);
else
} else
runtime·MHeap_Free(&runtime·mheap, s, 1);
c->local_nlargefree++;
c->local_largefree += size;
......@@ -376,7 +364,6 @@ runtime·mlookup(void *v, byte **base, uintptr *size, MSpan **sp)
if(sp)
*sp = s;
if(s == nil) {
runtime·checkfreed(v, 1);
if(base)
*base = nil;
if(size)
......@@ -713,140 +700,38 @@ runtime·persistentalloc(uintptr size, uintptr align, uint64 *stat)
return p;
}
static void
settype(MSpan *s, void *v, uintptr typ)
{
uintptr size, ofs, j, t;
uintptr ntypes, nbytes2, nbytes3;
uintptr *data2;
byte *data3;
if(s->sizeclass == 0) {
s->types.compression = MTypes_Single;
s->types.data = typ;
return;
}
size = s->elemsize;
ofs = ((uintptr)v - (s->start<<PageShift)) / size;
switch(s->types.compression) {
case MTypes_Empty:
ntypes = (s->npages << PageShift) / size;
nbytes3 = 8*sizeof(uintptr) + 1*ntypes;
data3 = runtime·mallocgc(nbytes3, 0, FlagNoProfiling|FlagNoScan|FlagNoInvokeGC);
s->types.compression = MTypes_Bytes;
s->types.data = (uintptr)data3;
((uintptr*)data3)[1] = typ;
data3[8*sizeof(uintptr) + ofs] = 1;
break;
case MTypes_Words:
((uintptr*)s->types.data)[ofs] = typ;
break;
case MTypes_Bytes:
data3 = (byte*)s->types.data;
for(j=1; j<8; j++) {
if(((uintptr*)data3)[j] == typ) {
break;
}
if(((uintptr*)data3)[j] == 0) {
((uintptr*)data3)[j] = typ;
break;
}
}
if(j < 8) {
data3[8*sizeof(uintptr) + ofs] = j;
} else {
ntypes = (s->npages << PageShift) / size;
nbytes2 = ntypes * sizeof(uintptr);
data2 = runtime·mallocgc(nbytes2, 0, FlagNoProfiling|FlagNoScan|FlagNoInvokeGC);
s->types.compression = MTypes_Words;
s->types.data = (uintptr)data2;
// Move the contents of data3 to data2. Then deallocate data3.
for(j=0; j<ntypes; j++) {
t = data3[8*sizeof(uintptr) + j];
t = ((uintptr*)data3)[t];
data2[j] = t;
}
data2[ofs] = typ;
}
break;
}
}
uintptr
runtime·gettype(void *v)
{
MSpan *s;
uintptr t, ofs;
byte *data;
s = runtime·MHeap_LookupMaybe(&runtime·mheap, v);
if(s != nil) {
t = 0;
switch(s->types.compression) {
case MTypes_Empty:
break;
case MTypes_Single:
t = s->types.data;
break;
case MTypes_Words:
ofs = (uintptr)v - (s->start<<PageShift);
t = ((uintptr*)s->types.data)[ofs/s->elemsize];
break;
case MTypes_Bytes:
ofs = (uintptr)v - (s->start<<PageShift);
data = (byte*)s->types.data;
t = data[8*sizeof(uintptr) + ofs/s->elemsize];
t = ((uintptr*)data)[t];
break;
default:
runtime·throw("runtime·gettype: invalid compression kind");
}
if(0) {
runtime·printf("%p -> %d,%X\n", v, (int32)s->types.compression, (int64)t);
}
return t;
}
return 0;
}
// Runtime stubs.
void*
runtime·mal(uintptr n)
{
return runtime·mallocgc(n, 0, 0);
return runtime·mallocgc(n, nil, 0);
}
#pragma textflag NOSPLIT
func new(typ *Type) (ret *uint8) {
ret = runtime·mallocgc(typ->size, (uintptr)typ | TypeInfo_SingleObject, typ->kind&KindNoPointers ? FlagNoScan : 0);
ret = runtime·mallocgc(typ->size, typ, typ->kind&KindNoPointers ? FlagNoScan : 0);
}
static void*
cnew(Type *typ, intgo n, int32 objtyp)
cnew(Type *typ, intgo n)
{
if((objtyp&(PtrSize-1)) != objtyp)
runtime·throw("runtime: invalid objtyp");
if(n < 0 || (typ->size > 0 && n > MaxMem/typ->size))
runtime·panicstring("runtime: allocation size out of range");
return runtime·mallocgc(typ->size*n, (uintptr)typ | objtyp, typ->kind&KindNoPointers ? FlagNoScan : 0);
return runtime·mallocgc(typ->size*n, typ, typ->kind&KindNoPointers ? FlagNoScan : 0);
}
// same as runtime·new, but callable from C
void*
runtime·cnew(Type *typ)
{
return cnew(typ, 1, TypeInfo_SingleObject);
return cnew(typ, 1);
}
void*
runtime·cnewarray(Type *typ, intgo n)
{
return cnew(typ, n, TypeInfo_Array);
return cnew(typ, n);
}
func GC() {
......@@ -868,7 +753,7 @@ func SetFinalizer(obj Eface, finalizer Eface) {
runtime·printf("runtime.SetFinalizer: first argument is nil interface\n");
goto throw;
}
if(obj.type->kind != KindPtr) {
if((obj.type->kind&KindMask) != KindPtr) {
runtime·printf("runtime.SetFinalizer: first argument is %S, not pointer\n", *obj.type->string);
goto throw;
}
......@@ -937,3 +822,9 @@ badfunc:
throw:
runtime·throw("runtime.SetFinalizer");
}
// For testing.
func GCMask(x Eface) (mask Slice) {
runtime·getgcmask(x.data, x.type, &mask.array, &mask.len);
mask.cap = mask.len;
}
src/pkg/runtime/malloc.h
View file @ cd17a717
......@@ -85,7 +85,6 @@ typedef struct MHeap MHeap;
typedef struct MSpan MSpan;
typedef struct MStats MStats;
typedef struct MLink MLink;
typedef struct MTypes MTypes;
typedef struct GCStats GCStats;
enum
......@@ -348,43 +347,6 @@ void runtime·MCache_Free(MCache *c, MLink *p, int32 sizeclass, uintptr size);
void runtime·MCache_ReleaseAll(MCache *c);
void runtime·stackcache_clear(MCache *c);
// MTypes describes the types of blocks allocated within a span.
// The compression field describes the layout of the data.
//
// MTypes_Empty:
// All blocks are free, or no type information is available for
// allocated blocks.
// The data field has no meaning.
// MTypes_Single:
// The span contains just one block.
// The data field holds the type information.
// The sysalloc field has no meaning.
// MTypes_Words:
// The span contains multiple blocks.
// The data field points to an array of type [NumBlocks]uintptr,
// and each element of the array holds the type of the corresponding
// block.
// MTypes_Bytes:
// The span contains at most seven different types of blocks.
// The data field points to the following structure:
// struct {
// type [8]uintptr // type[0] is always 0
// index [NumBlocks]byte
// }
// The type of the i-th block is: data.type[data.index[i]]
enum
{
MTypes_Empty = 0,
MTypes_Single = 1,
MTypes_Words = 2,
MTypes_Bytes = 3,
};
struct MTypes
{
byte compression; // one of MTypes_*
uintptr data;
};
enum
{
KindSpecialFinalizer = 1,
......@@ -454,7 +416,6 @@ struct MSpan
int64 unusedsince; // First time spotted by GC in MSpanFree state
uintptr npreleased; // number of pages released to the OS
byte *limit; // end of data in span
MTypes types; // types of allocated objects in this span
Lock specialLock; // guards specials list
Special *specials; // linked list of special records sorted by offset.
MLink *freebuf; // objects freed explicitly, not incorporated into freelist yet
......@@ -554,28 +515,22 @@ void runtime·MHeap_MapBits(MHeap *h);
void runtime·MHeap_MapSpans(MHeap *h);
void runtime·MHeap_Scavenger(void);
void* runtime·mallocgc(uintptr size, uintptr typ, uint32 flag);
void* runtime·mallocgc(uintptr size, Type* typ, uint32 flag);
void* runtime·persistentalloc(uintptr size, uintptr align, uint64 *stat);
int32 runtime·mlookup(void *v, byte **base, uintptr *size, MSpan **s);
void runtime·gc(int32 force);
uintptr runtime·sweepone(void);
void runtime·markscan(void *v);
void runtime·marknogc(void *v);
void runtime·checkallocated(void *v, uintptr n);
void runtime·markallocated(void *v, uintptr size, uintptr size0, Type* typ, bool scan);
void runtime·markfreed(void *v);
void runtime·checkfreed(void *v, uintptr n);
extern int32 runtime·checking;
void runtime·markspan(void *v, uintptr size, uintptr n, bool leftover);
void runtime·unmarkspan(void *v, uintptr size);
void runtime·purgecachedstats(MCache*);
void* runtime·cnew(Type*);
void* runtime·cnewarray(Type*, intgo);
void runtime·tracealloc(void*, uintptr, uintptr);
void runtime·tracealloc(void*, uintptr, Type*);
void runtime·tracefree(void*, uintptr);
void runtime·tracegc(void);
uintptr runtime·gettype(void*);
enum
{
// flags to malloc
......@@ -595,6 +550,7 @@ void runtime·helpgc(int32 nproc);
void runtime·gchelper(void);
void runtime·createfing(void);
G* runtime·wakefing(void);
void runtime·getgcmask(byte*, Type*, byte**, uintptr*);
extern bool runtime·fingwait;
extern bool runtime·fingwake;
......@@ -607,16 +563,6 @@ void runtime·queuefinalizer(byte *p, FuncVal *fn, uintptr nret, Type *fint, Ptr
void runtime·freeallspecials(MSpan *span, void *p, uintptr size);
bool runtime·freespecial(Special *s, void *p, uintptr size, bool freed);
enum
{
TypeInfo_SingleObject = 0,
TypeInfo_Array = 1,
TypeInfo_Chan = 2,
// Enables type information at the end of blocks allocated from heap
DebugTypeAtBlockEnd = 0,
};
// Information from the compiler about the layout of stack frames.
typedef struct BitVector BitVector;
struct BitVector
......@@ -631,20 +577,6 @@ struct StackMap
int32 nbit; // number of bits in each bitmap
uint32 data[];
};
enum {
// Pointer map
BitsPerPointer = 2,
BitsDead = 0,
BitsScalar = 1,
BitsPointer = 2,
BitsMultiWord = 3,
// BitsMultiWord will be set for the first word of a multi-word item.
// When it is set, one of the following will be set for the second word.
BitsString = 0,
BitsSlice = 1,
BitsIface = 2,
BitsEface = 3,
};
// Returns pointer map data for the given stackmap index
// (the index is encoded in PCDATA_StackMapIndex).
BitVector runtime·stackmapdata(StackMap *stackmap, int32 n);
......@@ -654,7 +586,6 @@ void runtime·gc_m_ptr(Eface*);
void runtime·gc_g_ptr(Eface*);
void runtime·gc_itab_ptr(Eface*);
void runtime·memorydump(void);
int32 runtime·setgcpercent(int32);
// Value we use to mark dead pointers when GODEBUG=gcdead=1.
......
src/pkg/runtime/malloc_test.go
View file @ cd17a717
......@@ -68,6 +68,19 @@ func BenchmarkMallocTypeInfo16(b *testing.B) {
mallocSink = x
}
type LargeStruct struct {
x [16][]byte
}
func BenchmarkMallocLargeStruct(b *testing.B) {
var x uintptr
for i := 0; i < b.N; i++ {
p := make([]LargeStruct, 2)
x ^= uintptr(unsafe.Pointer(&p[0]))
}
mallocSink = x
}
var n = flag.Int("n", 1000, "number of goroutines")
func BenchmarkGoroutineSelect(b *testing.B) {
......
src/pkg/runtime/mgc0.c
View file @ cd17a717
......@@ -64,28 +64,20 @@
enum {
Debug = 0,
CollectStats = 0,
ConcurrentSweep = 1,
PreciseScan = 1,
WorkbufSize = 16*1024,
WorkbufSize = 4*1024,
FinBlockSize = 4*1024,
handoffThreshold = 4,
IntermediateBufferCapacity = 64,
// Bits in type information
PRECISE = 1,
LOOP = 2,
PC_BITS = PRECISE | LOOP,
RootData = 0,
RootBss = 1,
RootFinalizers = 2,
RootSpanTypes = 3,
RootSpans = 3,
RootFlushCaches = 4,
RootCount = 5,
};
#define ScanConservatively ((byte*)1)
#define GcpercentUnknown (-2)
// Initialized from $GOGC. GOGC=off means no gc.
......@@ -138,23 +130,12 @@ clearpools(void)
//
uint32 runtime·worldsema = 1;
typedef struct Obj Obj;
struct Obj
{
byte *p; // data pointer
uintptr n; // size of data in bytes
uintptr ti; // type info
};
typedef struct Workbuf Workbuf;
struct Workbuf
{
#define SIZE (WorkbufSize-sizeof(LFNode)-sizeof(uintptr))
LFNode node; // must be first
uintptr nobj;
Obj obj[SIZE/sizeof(Obj) - 1];
uint8 _padding[SIZE%sizeof(Obj) + sizeof(Obj)];
#undef SIZE
byte* obj[(WorkbufSize-sizeof(LFNode)-sizeof(uintptr))/PtrSize];
};
typedef struct Finalizer Finalizer;
......@@ -203,8 +184,9 @@ static void putempty(Workbuf*);
static Workbuf* handoff(Workbuf*);
static void gchelperstart(void);
static void flushallmcaches(void);
static bool scanframe(Stkframe *frame, void *wbufp);
static void addstackroots(G *gp, Workbuf **wbufp);
static bool scanframe(Stkframe *frame, void *unused);
static void scanstack(G *gp);
static byte* unrollglobgcprog(byte *prog, uintptr size);
static FuncVal runfinqv = {runfinq};
static FuncVal bgsweepv = {bgsweep};
......@@ -218,1002 +200,300 @@ static struct {
volatile uint32 nwait;
volatile uint32 ndone;
Note alldone;
ParFor *markfor;
ParFor* markfor;
byte* gcdata;
byte* gcbss;
} work;
enum {
GC_DEFAULT_PTR = GC_NUM_INSTR,
GC_CHAN,
GC_NUM_INSTR2
};
static struct {
struct {
uint64 sum;
uint64 cnt;
} ptr;
uint64 nbytes;
struct {
uint64 sum;
uint64 cnt;
uint64 notype;
uint64 typelookup;
} obj;
uint64 rescan;
uint64 rescanbytes;
uint64 instr[GC_NUM_INSTR2];
uint64 putempty;
uint64 getfull;
struct {
uint64 foundbit;
uint64 foundword;
uint64 foundspan;
} flushptrbuf;
struct {
uint64 foundbit;
uint64 foundword;
uint64 foundspan;
} markonly;
uint32 nbgsweep;
uint32 npausesweep;
} gcstats;
// markonly marks an object. It returns true if the object
// has been marked by this function, false otherwise.
// This function doesn't append the object to any buffer.
static bool
markonly(void *obj)
{
byte *p;
uintptr *bitp, bits, shift, x, xbits, off;
MSpan *s;
PageID k;
// Words outside the arena cannot be pointers.
if(obj < runtime·mheap.arena_start || obj >= runtime·mheap.arena_used)
return false;
// obj may be a pointer to a live object.
// Try to find the beginning of the object.
// Round down to word boundary.
obj = (void*)((uintptr)obj & ~((uintptr)PtrSize-1));
// Find bits for this word.
off = (uintptr*)obj - (uintptr*)runtime·mheap.arena_start;
bitp = (uintptr*)runtime·mheap.arena_start - off/wordsPerBitmapWord - 1;
shift = off % wordsPerBitmapWord;
xbits = *bitp;
bits = xbits >> shift;
// Pointing at the beginning of a block?
if((bits & (bitAllocated|bitBlockBoundary)) != 0) {
if(CollectStats)
runtime·xadd64(&gcstats.markonly.foundbit, 1);
goto found;
}
// Otherwise consult span table to find beginning.
// (Manually inlined copy of MHeap_LookupMaybe.)
k = (uintptr)obj>>PageShift;
x = k;
x -= (uintptr)runtime·mheap.arena_start>>PageShift;
s = runtime·mheap.spans[x];
if(s == nil || k < s->start || obj >= s->limit || s->state != MSpanInUse)
return false;
p = (byte*)((uintptr)s->start<<PageShift);
if(s->sizeclass == 0) {
obj = p;
} else {
uintptr size = s->elemsize;
int32 i = ((byte*)obj - p)/size;
obj = p+i*size;
}
// Now that we know the object header, reload bits.
off = (uintptr*)obj - (uintptr*)runtime·mheap.arena_start;
bitp = (uintptr*)runtime·mheap.arena_start - off/wordsPerBitmapWord - 1;
shift = off % wordsPerBitmapWord;
xbits = *bitp;
bits = xbits >> shift;
if(CollectStats)
runtime·xadd64(&gcstats.markonly.foundspan, 1);
found:
// Now we have bits, bitp, and shift correct for
// obj pointing at the base of the object.
// Only care about allocated and not marked.
if((bits & (bitAllocated|bitMarked)) != bitAllocated)
return false;
if(work.nproc == 1)
*bitp |= bitMarked<<shift;
else {
for(;;) {
x = *bitp;
if(x & (bitMarked<<shift))
return false;
if(runtime·casp((void**)bitp, (void*)x, (void*)(x|(bitMarked<<shift))))
break;
}
}
// The object is now marked
return true;
}
// PtrTarget is a structure used by intermediate buffers.
// The intermediate buffers hold GC data before it
// is moved/flushed to the work buffer (Workbuf).
// The size of an intermediate buffer is very small,
// such as 32 or 64 elements.
typedef struct PtrTarget PtrTarget;
struct PtrTarget
{
void *p;
uintptr ti;
};
typedef struct Scanbuf Scanbuf;
struct Scanbuf
{
struct {
PtrTarget *begin;
PtrTarget *end;
PtrTarget *pos;
} ptr;
struct {
Obj *begin;
Obj *end;
Obj *pos;
} obj;
Workbuf *wbuf;
Obj *wp;
uintptr nobj;
};
typedef struct BufferList BufferList;
struct BufferList
{
PtrTarget ptrtarget[IntermediateBufferCapacity];
Obj obj[IntermediateBufferCapacity];
uint32 busy;
byte pad[CacheLineSize];
};
#pragma dataflag NOPTR
static BufferList bufferList[MaxGcproc];
static Type *itabtype;
static void enqueue(Obj obj, Workbuf **_wbuf, Obj **_wp, uintptr *_nobj);
// flushptrbuf moves data from the PtrTarget buffer to the work buffer.
// The PtrTarget buffer contains blocks irrespective of whether the blocks have been marked or scanned,
// while the work buffer contains blocks which have been marked
// and are prepared to be scanned by the garbage collector.
//
// _wp, _wbuf, _nobj are input/output parameters and are specifying the work buffer.
//
// A simplified drawing explaining how the todo-list moves from a structure to another:
//
// scanblock
// (find pointers)
// Obj ------> PtrTarget (pointer targets)
// ↑ |
// | |
// `----------'
// flushptrbuf
// (find block start, mark and enqueue)
// scanblock scans a block of n bytes starting at pointer b for references
// to other objects, scanning any it finds recursively until there are no
// unscanned objects left. Instead of using an explicit recursion, it keeps
// a work list in the Workbuf* structures and loops in the main function
// body. Keeping an explicit work list is easier on the stack allocator and
// more efficient.
static void
flushptrbuf(Scanbuf *sbuf)
scanblock(byte *b, uintptr n, byte *ptrmask)
{
byte *p, *arena_start, *obj;
uintptr size, *bitp, bits, shift, x, xbits, off, nobj, ti, n;
byte *obj, *p, *arena_start, *arena_used, **wp, *scanbuf[8];
uintptr i, nobj, size, idx, *bitp, bits, xbits, shift, x, off, cached, scanbufpos;
intptr ncached;
Workbuf *wbuf;
String *str;
Slice *slice;
Iface *iface;
Eface *eface;
Type *typ;
MSpan *s;
PageID k;
Obj *wp;
Workbuf *wbuf;
PtrTarget *ptrbuf;
PtrTarget *ptrbuf_end;
bool keepworking;
// Cache memory arena parameters in local vars.
arena_start = runtime·mheap.arena_start;
arena_used = runtime·mheap.arena_used;
wp = sbuf->wp;
wbuf = sbuf->wbuf;
nobj = sbuf->nobj;
ptrbuf = sbuf->ptr.begin;
ptrbuf_end = sbuf->ptr.pos;
n = ptrbuf_end - sbuf->ptr.begin;
sbuf->ptr.pos = sbuf->ptr.begin;
if(CollectStats) {
runtime·xadd64(&gcstats.ptr.sum, n);
runtime·xadd64(&gcstats.ptr.cnt, 1);
}
// If buffer is nearly full, get a new one.
if(wbuf == nil || nobj+n >= nelem(wbuf->obj)) {
if(wbuf != nil)
wbuf->nobj = nobj;
wbuf = getempty(wbuf);
wp = wbuf->obj;
nobj = 0;
if(n >= nelem(wbuf->obj))
runtime·throw("ptrbuf has to be smaller than WorkBuf");
}
while(ptrbuf < ptrbuf_end) {
obj = ptrbuf->p;
ti = ptrbuf->ti;
ptrbuf++;
// obj belongs to interval [mheap.arena_start, mheap.arena_used).
if(Debug > 1) {
if(obj < runtime·mheap.arena_start || obj >= runtime·mheap.arena_used)
runtime·throw("object is outside of mheap");
}
// obj may be a pointer to a live object.
// Try to find the beginning of the object.
// Round down to word boundary.
if(((uintptr)obj & ((uintptr)PtrSize-1)) != 0) {
obj = (void*)((uintptr)obj & ~((uintptr)PtrSize-1));
ti = 0;
}
// Find bits for this word.
off = (uintptr*)obj - (uintptr*)arena_start;
bitp = (uintptr*)arena_start - off/wordsPerBitmapWord - 1;
shift = off % wordsPerBitmapWord;
xbits = *bitp;
bits = xbits >> shift;
// Pointing at the beginning of a block?
if((bits & (bitAllocated|bitBlockBoundary)) != 0) {
if(CollectStats)
runtime·xadd64(&gcstats.flushptrbuf.foundbit, 1);
goto found;
}
ti = 0;
// Otherwise consult span table to find beginning.
// (Manually inlined copy of MHeap_LookupMaybe.)
k = (uintptr)obj>>PageShift;
x = k;
x -= (uintptr)arena_start>>PageShift;
s = runtime·mheap.spans[x];
if(s == nil || k < s->start || obj >= s->limit || s->state != MSpanInUse)
continue;
p = (byte*)((uintptr)s->start<<PageShift);
if(s->sizeclass == 0) {
obj = p;
} else {
size = s->elemsize;
int32 i = ((byte*)obj - p)/size;
obj = p+i*size;
}
// Now that we know the object header, reload bits.
off = (uintptr*)obj - (uintptr*)arena_start;
bitp = (uintptr*)arena_start - off/wordsPerBitmapWord - 1;
shift = off % wordsPerBitmapWord;
xbits = *bitp;
bits = xbits >> shift;
if(CollectStats)
runtime·xadd64(&gcstats.flushptrbuf.foundspan, 1);
found:
// Now we have bits, bitp, and shift correct for
// obj pointing at the base of the object.
// Only care about allocated and not marked.
if((bits & (bitAllocated|bitMarked)) != bitAllocated)
continue;
if(work.nproc == 1)
*bitp |= bitMarked<<shift;
else {
wbuf = getempty(nil);
nobj = wbuf->nobj;
wp = &wbuf->obj[nobj];
keepworking = b == nil;
scanbufpos = 0;
for(i = 0; i < nelem(scanbuf); i++)
scanbuf[i] = nil;
// ptrmask can have 3 possible values:
// 1. nil - obtain pointer mask from GC bitmap.
// 2. ScanConservatively - don't use any mask, scan conservatively.
// 3. pointer to a compact mask (for stacks and data).
if(b != nil)
goto scanobj;
for(;;) {
x = *bitp;
if(x & (bitMarked<<shift))
goto continue_obj;
if(runtime·casp((void**)bitp, (void*)x, (void*)(x|(bitMarked<<shift))))
break;
if(nobj == 0) {
// Out of work in workbuf.
// First, see is there is any work in scanbuf.
for(i = 0; i < nelem(scanbuf); i++) {
b = scanbuf[scanbufpos];
scanbuf[scanbufpos++] = nil;
if(scanbufpos == nelem(scanbuf))
scanbufpos = 0;
if(b != nil) {
n = arena_used - b; // scan until bitBoundary or BitsDead
ptrmask = nil; // use GC bitmap for pointer info
goto scanobj;
}
}
// If object has no pointers, don't need to scan further.
if((bits & bitScan) == 0)
continue;
// Ask span about size class.
// (Manually inlined copy of MHeap_Lookup.)
x = (uintptr)obj >> PageShift;
x -= (uintptr)arena_start>>PageShift;
s = runtime·mheap.spans[x];
PREFETCH(obj);
*wp = (Obj){obj, s->elemsize, ti};
wp++;
nobj++;
continue_obj:;
if(!keepworking) {
putempty(wbuf);
return;
}
// If another proc wants a pointer, give it some.
if(work.nwait > 0 && nobj > handoffThreshold && work.full == 0) {
wbuf->nobj = nobj;
wbuf = handoff(wbuf);
// Refill workbuf from global queue.
wbuf = getfull(wbuf);
if(wbuf == nil)
return;
nobj = wbuf->nobj;
wp = wbuf->obj + nobj;
}
sbuf->wp = wp;
sbuf->wbuf = wbuf;
sbuf->nobj = nobj;
}
static void
flushobjbuf(Scanbuf *sbuf)
{
uintptr nobj, off;
Obj *wp, obj;
Workbuf *wbuf;
Obj *objbuf;
Obj *objbuf_end;
wp = sbuf->wp;
wbuf = sbuf->wbuf;
nobj = sbuf->nobj;
objbuf = sbuf->obj.begin;
objbuf_end = sbuf->obj.pos;
sbuf->obj.pos = sbuf->obj.begin;
while(objbuf < objbuf_end) {
obj = *objbuf++;
// Align obj.b to a word boundary.
off = (uintptr)obj.p & (PtrSize-1);
if(off != 0) {
obj.p += PtrSize - off;
obj.n -= PtrSize - off;
obj.ti = 0;
}
if(obj.p == nil || obj.n == 0)
continue;
// If buffer is full, get a new one.
if(wbuf == nil || nobj >= nelem(wbuf->obj)) {
if(wbuf != nil)
wbuf->nobj = nobj;
wbuf = getempty(wbuf);
wp = wbuf->obj;
nobj = 0;
}
*wp = obj;
wp++;
nobj++;
wp = &wbuf->obj[nobj];
}
// If another proc wants a pointer, give it some.
if(work.nwait > 0 && nobj > handoffThreshold && work.full == 0) {
if(work.nwait > 0 && nobj > 4 && work.full == 0) {
wbuf->nobj = nobj;
wbuf = handoff(wbuf);
nobj = wbuf->nobj;
wp = wbuf->obj + nobj;
}
sbuf->wp = wp;
sbuf->wbuf = wbuf;
sbuf->nobj = nobj;
}
// Program that scans the whole block and treats every block element as a potential pointer
static uintptr defaultProg[2] = {PtrSize, GC_DEFAULT_PTR};
// Hchan program
static uintptr chanProg[2] = {0, GC_CHAN};
// Local variables of a program fragment or loop
typedef struct Frame Frame;
struct Frame {
uintptr count, elemsize, b;
uintptr *loop_or_ret;
};
// Sanity check for the derived type info objti.
static void
checkptr(void *obj, uintptr objti)
{
uintptr *pc1, *pc2, type, tisize, i, j, x;
byte *objstart;
Type *t;
MSpan *s;
if(!Debug)
runtime·throw("checkptr is debug only");
if(obj < runtime·mheap.arena_start || obj >= runtime·mheap.arena_used)
return;
type = runtime·gettype(obj);
t = (Type*)(type & ~(uintptr)(PtrSize-1));
if(t == nil)
return;
x = (uintptr)obj >> PageShift;
x -= (uintptr)(runtime·mheap.arena_start)>>PageShift;
s = runtime·mheap.spans[x];
objstart = (byte*)((uintptr)s->start<<PageShift);
if(s->sizeclass != 0) {
i = ((byte*)obj - objstart)/s->elemsize;
objstart += i*s->elemsize;
}
tisize = *(uintptr*)objti;
// Sanity check for object size: it should fit into the memory block.
if((byte*)obj + tisize > objstart + s->elemsize) {
runtime·printf("object of type '%S' at %p/%p does not fit in block %p/%p\n",
*t->string, obj, tisize, objstart, s->elemsize);
runtime·throw("invalid gc type info");
}
if(obj != objstart)
return;
// If obj points to the beginning of the memory block,
// check type info as well.
if(t->string == nil ||
// Gob allocates unsafe pointers for indirection.
(runtime·strcmp(t->string->str, (byte*)"unsafe.Pointer") &&
// Runtime and gc think differently about closures.
runtime·strstr(t->string->str, (byte*)"struct { F uintptr") != t->string->str)) {
pc1 = (uintptr*)objti;
pc2 = (uintptr*)t->gc;
// A simple best-effort check until first GC_END.
for(j = 1; pc1[j] != GC_END && pc2[j] != GC_END; j++) {
if(pc1[j] != pc2[j]) {
runtime·printf("invalid gc type info for '%s', type info %p [%d]=%p, block info %p [%d]=%p\n",
t->string ? (int8*)t->string->str : (int8*)"?", pc1, (int32)j, pc1[j], pc2, (int32)j, pc2[j]);
runtime·throw("invalid gc type info");
}
}
}
}
// scanblock scans a block of n bytes starting at pointer b for references
// to other objects, scanning any it finds recursively until there are no
// unscanned objects left. Instead of using an explicit recursion, it keeps
// a work list in the Workbuf* structures and loops in the main function
// body. Keeping an explicit work list is easier on the stack allocator and
// more efficient.
static void
scanblock(Workbuf *wbuf, bool keepworking)
{
byte *b, *arena_start, *arena_used;
uintptr n, i, end_b, elemsize, size, ti, objti, count, type, nobj;
uintptr *pc, precise_type, nominal_size;
uintptr *chan_ret, chancap;
void *obj;
Type *t, *et;
Slice *sliceptr;
String *stringptr;
Frame *stack_ptr, stack_top, stack[GC_STACK_CAPACITY+4];
BufferList *scanbuffers;
Scanbuf sbuf;
Eface *eface;
Iface *iface;
Hchan *chan;
ChanType *chantype;
Obj *wp;
if(sizeof(Workbuf) % WorkbufSize != 0)
runtime·throw("scanblock: size of Workbuf is suboptimal");
// Memory arena parameters.
arena_start = runtime·mheap.arena_start;
arena_used = runtime·mheap.arena_used;
stack_ptr = stack+nelem(stack)-1;
precise_type = false;
nominal_size = 0;
if(wbuf) {
nobj = wbuf->nobj;
wp = &wbuf->obj[nobj];
} else {
nobj = 0;
wp = nil;
}
// Initialize sbuf
scanbuffers = &bufferList[g->m->helpgc];
sbuf.ptr.begin = sbuf.ptr.pos = &scanbuffers->ptrtarget[0];
sbuf.ptr.end = sbuf.ptr.begin + nelem(scanbuffers->ptrtarget);
sbuf.obj.begin = sbuf.obj.pos = &scanbuffers->obj[0];
sbuf.obj.end = sbuf.obj.begin + nelem(scanbuffers->obj);
sbuf.wbuf = wbuf;
sbuf.wp = wp;
sbuf.nobj = nobj;
wp--;
nobj--;
b = *wp;
n = arena_used - b; // scan until next bitBoundary or BitsDead
ptrmask = nil; // use GC bitmap for pointer info
// (Silence the compiler)
chan = nil;
chantype = nil;
chan_ret = nil;
goto next_block;
for(;;) {
// Each iteration scans the block b of length n, queueing pointers in
// the work buffer.
if(CollectStats) {
runtime·xadd64(&gcstats.nbytes, n);
runtime·xadd64(&gcstats.obj.sum, sbuf.nobj);
runtime·xadd64(&gcstats.obj.cnt, 1);
}
if(ti != 0) {
if(Debug > 1) {
runtime·printf("scanblock %p %D ti %p\n", b, (int64)n, ti);
}
pc = (uintptr*)(ti & ~(uintptr)PC_BITS);
precise_type = (ti & PRECISE);
stack_top.elemsize = pc[0];
if(!precise_type)
nominal_size = pc[0];
if(ti & LOOP) {
stack_top.count = 0; // 0 means an infinite number of iterations
stack_top.loop_or_ret = pc+1;
} else {
stack_top.count = 1;
}
if(Debug) {
// Simple sanity check for provided type info ti:
// The declared size of the object must be not larger than the actual size
// (it can be smaller due to inferior pointers).
// It's difficult to make a comprehensive check due to inferior pointers,
// reflection, gob, etc.
if(pc[0] > n) {
runtime·printf("invalid gc type info: type info size %p, block size %p\n", pc[0], n);
runtime·throw("invalid gc type info");
}
}
} else if(UseSpanType) {
if(CollectStats)
runtime·xadd64(&gcstats.obj.notype, 1);
type = runtime·gettype(b);
if(type != 0) {
if(CollectStats)
runtime·xadd64(&gcstats.obj.typelookup, 1);
t = (Type*)(type & ~(uintptr)(PtrSize-1));
switch(type & (PtrSize-1)) {
case TypeInfo_SingleObject:
pc = (uintptr*)t->gc;
precise_type = true; // type information about 'b' is precise
stack_top.count = 1;
stack_top.elemsize = pc[0];
break;
case TypeInfo_Array:
pc = (uintptr*)t->gc;
if(pc[0] == 0)
goto next_block;
precise_type = true; // type information about 'b' is precise
stack_top.count = 0; // 0 means an infinite number of iterations
stack_top.elemsize = pc[0];
stack_top.loop_or_ret = pc+1;
break;
case TypeInfo_Chan:
chan = (Hchan*)b;
chantype = (ChanType*)t;
chan_ret = nil;
pc = chanProg;
break;
default:
if(Debug > 1)
runtime·printf("scanblock %p %D type %p %S\n", b, (int64)n, type, *t->string);
runtime·throw("scanblock: invalid type");
return;
scanobj:
if(!PreciseScan) {
if(ptrmask == nil) {
// Heap obj, obtain real size.
if(!runtime·mlookup(b, &p, &n, nil))
continue; // not an allocated obj
if(b != p)
runtime·throw("bad heap object");
}
if(Debug > 1)
runtime·printf("scanblock %p %D type %p %S pc=%p\n", b, (int64)n, type, *t->string, pc);
} else {
pc = defaultProg;
if(Debug > 1)
runtime·printf("scanblock %p %D unknown type\n", b, (int64)n);
ptrmask = ScanConservatively;
}
} else {
pc = defaultProg;
if(Debug > 1)
runtime·printf("scanblock %p %D no span types\n", b, (int64)n);
}
if(IgnorePreciseGC)
pc = defaultProg;
pc++;
stack_top.b = (uintptr)b;
end_b = (uintptr)b + n - PtrSize;
for(;;) {
if(CollectStats)
runtime·xadd64(&gcstats.instr[pc[0]], 1);
cached = 0;
ncached = 0;
for(i = 0; i < n; i += PtrSize) {
obj = nil;
objti = 0;
switch(pc[0]) {
case GC_PTR:
obj = *(void**)(stack_top.b + pc[1]);
objti = pc[2];
if(Debug > 2)
runtime·printf("gc_ptr @%p: %p ti=%p\n", stack_top.b+pc[1], obj, objti);
pc += 3;
if(Debug)
checkptr(obj, objti);
break;
case GC_SLICE:
sliceptr = (Slice*)(stack_top.b + pc[1]);
if(Debug > 2)
runtime·printf("gc_slice @%p: %p/%D/%D\n", sliceptr, sliceptr->array, (int64)sliceptr->len, (int64)sliceptr->cap);
if(sliceptr->cap != 0) {
obj = sliceptr->array;
// Can't use slice element type for scanning,
// because if it points to an array embedded
// in the beginning of a struct,
// we will scan the whole struct as the slice.
// So just obtain type info from heap.
}
pc += 3;
break;
case GC_APTR:
obj = *(void**)(stack_top.b + pc[1]);
if(Debug > 2)
runtime·printf("gc_aptr @%p: %p\n", stack_top.b+pc[1], obj);
pc += 2;
// Find bits for this word.
if(ptrmask == nil) {
// Check is we have reached end of span.
if((((uintptr)b+i)%PageSize) == 0 &&
runtime·mheap.spans[(b-arena_start)>>PageShift] != runtime·mheap.spans[(b+i-arena_start)>>PageShift])
break;
// Consult GC bitmap.
if(ncached <= 0) {
// Refill cache.
off = (uintptr*)(b+i) - (uintptr*)arena_start;
bitp = (uintptr*)arena_start - off/wordsPerBitmapWord - 1;
shift = (off % wordsPerBitmapWord) * gcBits;
cached = *bitp >> shift;
ncached = (PtrSize*8 - shift)/gcBits;
}
bits = cached;
cached >>= gcBits;
ncached--;
if(i != 0 && (bits&bitMask) != bitMiddle)
break; // reached beginning of the next object
bits = (bits>>2)&BitsMask;
if(bits == BitsDead)
break; // reached no-scan part of the object
} else if(ptrmask != ScanConservatively) // dense mask (stack or data)
bits = (ptrmask[(i/PtrSize)/4]>>(((i/PtrSize)%4)*BitsPerPointer))&BitsMask;
else
bits = BitsPointer;
case GC_STRING:
stringptr = (String*)(stack_top.b + pc[1]);
if(Debug > 2)
runtime·printf("gc_string @%p: %p/%D\n", stack_top.b+pc[1], stringptr->str, (int64)stringptr->len);
if(stringptr->len != 0)
markonly(stringptr->str);
pc += 2;
continue;
case GC_EFACE:
eface = (Eface*)(stack_top.b + pc[1]);
pc += 2;
if(Debug > 2)
runtime·printf("gc_eface @%p: %p %p\n", stack_top.b+pc[1], eface->type, eface->data);
if(eface->type == nil)
if(bits == BitsScalar || bits == BitsDead)
continue;
// eface->type
t = eface->type;
if((void*)t >= arena_start && (void*)t < arena_used) {
*sbuf.ptr.pos++ = (PtrTarget){t, 0};
if(sbuf.ptr.pos == sbuf.ptr.end)
flushptrbuf(&sbuf);
if(bits == BitsPointer) {
obj = *(byte**)(b+i);
goto markobj;
}
// Find the next pair of bits.
if(ptrmask == nil) {
if(ncached <= 0) {
off = (uintptr*)(b+i+PtrSize) - (uintptr*)arena_start;
bitp = (uintptr*)arena_start - off/wordsPerBitmapWord - 1;
shift = (off % wordsPerBitmapWord) * gcBits;
cached = *bitp >> shift;
ncached = (PtrSize*8 - shift)/gcBits;
}
bits = (cached>>2)&BitsMask;
} else
bits = (ptrmask[((i+PtrSize)/PtrSize)/4]>>((((i+PtrSize)/PtrSize)%4)*BitsPerPointer))&BitsMask;
// eface->data
if(eface->data >= arena_start && eface->data < arena_used) {
if(t->size <= sizeof(void*)) {
if((t->kind & KindNoPointers))
continue;
obj = eface->data;
if((t->kind & ~KindNoPointers) == KindPtr) {
// Only use type information if it is a pointer-containing type.
// This matches the GC programs written by cmd/gc/reflect.c's
// dgcsym1 in case TPTR32/case TPTR64. See rationale there.
et = ((PtrType*)t)->elem;
if(!(et->kind & KindNoPointers))
objti = (uintptr)((PtrType*)t)->elem->gc;
}
} else {
obj = eface->data;
objti = (uintptr)t->gc;
}
}
switch(bits) {
case BitsString:
str = (String*)(b+i);
if(str->len > 0)
obj = str->str;
break;
case GC_IFACE:
iface = (Iface*)(stack_top.b + pc[1]);
pc += 2;
if(Debug > 2)
runtime·printf("gc_iface @%p: %p/%p %p\n", stack_top.b+pc[1], iface->tab, nil, iface->data);
if(iface->tab == nil)
continue;
// iface->tab
if((void*)iface->tab >= arena_start && (void*)iface->tab < arena_used) {
*sbuf.ptr.pos++ = (PtrTarget){iface->tab, (uintptr)itabtype->gc};
if(sbuf.ptr.pos == sbuf.ptr.end)
flushptrbuf(&sbuf);
}
// iface->data
if(iface->data >= arena_start && iface->data < arena_used) {
t = iface->tab->type;
if(t->size <= sizeof(void*)) {
if((t->kind & KindNoPointers))
continue;
obj = iface->data;
if((t->kind & ~KindNoPointers) == KindPtr) {
// Only use type information if it is a pointer-containing type.
// This matches the GC programs written by cmd/gc/reflect.c's
// dgcsym1 in case TPTR32/case TPTR64. See rationale there.
et = ((PtrType*)t)->elem;
if(!(et->kind & KindNoPointers))
objti = (uintptr)((PtrType*)t)->elem->gc;
case BitsSlice:
slice = (Slice*)(b+i);
if(Debug && slice->cap < slice->len) {
g->m->traceback = 2;
runtime·printf("bad slice in object %p: %p/%p/%p\n",
b, slice->array, slice->len, slice->cap);
runtime·throw("bad slice in heap object");
}
} else {
if(slice->cap > 0)
obj = slice->array;
break;
case BitsIface:
iface = (Iface*)(b+i);
if(iface->tab != nil) {
typ = iface->tab->type;
if(typ->size > PtrSize || !(typ->kind&KindNoPointers))
obj = iface->data;
objti = (uintptr)t->gc;
}
}
break;
case GC_DEFAULT_PTR:
while(stack_top.b <= end_b) {
obj = *(byte**)stack_top.b;
if(Debug > 2)
runtime·printf("gc_default_ptr @%p: %p\n", stack_top.b, obj);
stack_top.b += PtrSize;
if(obj >= arena_start && obj < arena_used) {
*sbuf.ptr.pos++ = (PtrTarget){obj, 0};
if(sbuf.ptr.pos == sbuf.ptr.end)
flushptrbuf(&sbuf);
}
}
goto next_block;
case GC_END:
if(--stack_top.count != 0) {
// Next iteration of a loop if possible.
stack_top.b += stack_top.elemsize;
if(stack_top.b + stack_top.elemsize <= end_b+PtrSize) {
pc = stack_top.loop_or_ret;
continue;
}
i = stack_top.b;
} else {
// Stack pop if possible.
if(stack_ptr+1 < stack+nelem(stack)) {
pc = stack_top.loop_or_ret;
stack_top = *(++stack_ptr);
continue;
}
i = (uintptr)b + nominal_size;
}
if(!precise_type) {
// Quickly scan [b+i,b+n) for possible pointers.
for(; i<=end_b; i+=PtrSize) {
if(*(byte**)i != nil) {
// Found a value that may be a pointer.
// Do a rescan of the entire block.
enqueue((Obj){b, n, 0}, &sbuf.wbuf, &sbuf.wp, &sbuf.nobj);
if(CollectStats) {
runtime·xadd64(&gcstats.rescan, 1);
runtime·xadd64(&gcstats.rescanbytes, n);
case BitsEface:
eface = (Eface*)(b+i);
typ = eface->type;
if(typ != nil) {
if(typ->size > PtrSize || !(typ->kind&KindNoPointers))
obj = eface->data;
}
break;
}
}
}
goto next_block;
case GC_ARRAY_START:
i = stack_top.b + pc[1];
count = pc[2];
elemsize = pc[3];
pc += 4;
// Stack push.
*stack_ptr-- = stack_top;
stack_top = (Frame){count, elemsize, i, pc};
continue;
case GC_ARRAY_NEXT:
if(--stack_top.count != 0) {
stack_top.b += stack_top.elemsize;
pc = stack_top.loop_or_ret;
if(bits == BitsSlice) {
i += 2*PtrSize;
cached >>= 2*gcBits;
ncached -= 2;
} else {
// Stack pop.
stack_top = *(++stack_ptr);
pc += 1;
i += PtrSize;
cached >>= gcBits;
ncached--;
}
continue;
case GC_CALL:
// Stack push.
*stack_ptr-- = stack_top;
stack_top = (Frame){1, 0, stack_top.b + pc[1], pc+3 /*return address*/};
pc = (uintptr*)((byte*)pc + *(int32*)(pc+2)); // target of the CALL instruction
markobj:
// At this point we have extracted the next potential pointer.
// Check if it points into heap.
if(obj == nil || obj < arena_start || obj >= arena_used)
continue;
case GC_REGION:
obj = (void*)(stack_top.b + pc[1]);
size = pc[2];
objti = pc[3];
pc += 4;
if(Debug > 2)
runtime·printf("gc_region @%p: %D %p\n", stack_top.b+pc[1], (int64)size, objti);
*sbuf.obj.pos++ = (Obj){obj, size, objti};
if(sbuf.obj.pos == sbuf.obj.end)
flushobjbuf(&sbuf);
continue;
case GC_CHAN_PTR:
chan = *(Hchan**)(stack_top.b + pc[1]);
if(Debug > 2 && chan != nil)
runtime·printf("gc_chan_ptr @%p: %p/%D/%D %p\n", stack_top.b+pc[1], chan, (int64)chan->qcount, (int64)chan->dataqsiz, pc[2]);
if(chan == nil) {
pc += 3;
// Mark the object.
off = (uintptr*)obj - (uintptr*)arena_start;
bitp = (uintptr*)arena_start - off/wordsPerBitmapWord - 1;
shift = (off % wordsPerBitmapWord) * gcBits;
xbits = *bitp;
bits = (xbits >> shift) & bitMask;
if(bits == bitMiddle) {
// Not a beginning of a block, check if we have block boundary in xbits.
while(shift > 0) {
obj -= PtrSize;
shift -= gcBits;
bits = (xbits >> shift) & bitMask;
if(bits != bitMiddle)
goto havebits;
}
// Otherwise consult span table to find the block beginning.
k = (uintptr)obj>>PageShift;
x = k;
x -= (uintptr)arena_start>>PageShift;
s = runtime·mheap.spans[x];
if(s == nil || k < s->start || obj >= s->limit || s->state != MSpanInUse)
continue;
p = (byte*)((uintptr)s->start<<PageShift);
if(s->sizeclass != 0) {
size = s->elemsize;
idx = ((byte*)obj - p)/size;
p = p+idx*size;
}
if(markonly(chan)) {
chantype = (ChanType*)pc[2];
if(!(chantype->elem->kind & KindNoPointers)) {
// Start chanProg.
chan_ret = pc+3;
pc = chanProg+1;
continue;
if(p == obj) {
runtime·printf("runtime: failed to find block beginning for %p s->limit=%p\n", p, s->limit);
runtime·throw("failed to find block beginning");
}
obj = p;
goto markobj;
}
pc += 3;
continue;
case GC_CHAN:
// There are no heap pointers in struct Hchan,
// so we can ignore the leading sizeof(Hchan) bytes.
if(!(chantype->elem->kind & KindNoPointers)) {
// Channel's buffer follows Hchan immediately in memory.
// Size of buffer (cap(c)) is second int in the chan struct.
chancap = ((uintgo*)chan)[1];
if(chancap > 0) {
// TODO(atom): split into two chunks so that only the
// in-use part of the circular buffer is scanned.
// (Channel routines zero the unused part, so the current
// code does not lead to leaks, it's just a little inefficient.)
*sbuf.obj.pos++ = (Obj){(byte*)chan+runtime·Hchansize, chancap*chantype->elem->size,
(uintptr)chantype->elem->gc | PRECISE | LOOP};
if(sbuf.obj.pos == sbuf.obj.end)
flushobjbuf(&sbuf);
}
}
if(chan_ret == nil)
goto next_block;
pc = chan_ret;
havebits:
// Now we have bits, bitp, and shift correct for
// obj pointing at the base of the object.
// Only care about allocated and not marked.
if(bits != bitAllocated)
continue;
default:
runtime·printf("runtime: invalid GC instruction %p at %p\n", pc[0], pc);
runtime·throw("scanblock: invalid GC instruction");
return;
}
if(obj >= arena_start && obj < arena_used) {
*sbuf.ptr.pos++ = (PtrTarget){obj, objti};
if(sbuf.ptr.pos == sbuf.ptr.end)
flushptrbuf(&sbuf);
}
}
next_block:
// Done scanning [b, b+n). Prepare for the next iteration of
// the loop by setting b, n, ti to the parameters for the next block.
if(sbuf.nobj == 0) {
flushptrbuf(&sbuf);
flushobjbuf(&sbuf);
if(sbuf.nobj == 0) {
if(!keepworking) {
if(sbuf.wbuf)
putempty(sbuf.wbuf);
return;
}
// Emptied our buffer: refill.
sbuf.wbuf = getfull(sbuf.wbuf);
if(sbuf.wbuf == nil)
return;
sbuf.nobj = sbuf.wbuf->nobj;
sbuf.wp = sbuf.wbuf->obj + sbuf.wbuf->nobj;
}
}
// Fetch b from the work buffer.
--sbuf.wp;
b = sbuf.wp->p;
n = sbuf.wp->n;
ti = sbuf.wp->ti;
sbuf.nobj--;
}
}
// Append obj to the work buffer.
// _wbuf, _wp, _nobj are input/output parameters and are specifying the work buffer.
static void
enqueue(Obj obj, Workbuf **_wbuf, Obj **_wp, uintptr *_nobj)
{
uintptr nobj, off;
Obj *wp;
Workbuf *wbuf;
if(Debug > 1)
runtime·printf("append obj(%p %D %p)\n", obj.p, (int64)obj.n, obj.ti);
// Align obj.b to a word boundary.
off = (uintptr)obj.p & (PtrSize-1);
if(off != 0) {
obj.p += PtrSize - off;
obj.n -= PtrSize - off;
obj.ti = 0;
if(work.nproc == 1)
*bitp |= bitMarked<<shift;
else {
for(;;) {
xbits = *bitp;
bits = (xbits>>shift) & bitMask;
if(bits != bitAllocated)
break;
if(runtime·casp((void**)bitp, (void*)xbits, (void*)(xbits|(bitMarked<<shift))))
break;
}
if(obj.p == nil || obj.n == 0)
return;
// Load work buffer state
wp = *_wp;
wbuf = *_wbuf;
nobj = *_nobj;
// If another proc wants a pointer, give it some.
if(work.nwait > 0 && nobj > handoffThreshold && work.full == 0) {
wbuf->nobj = nobj;
wbuf = handoff(wbuf);
nobj = wbuf->nobj;
wp = wbuf->obj + nobj;
if(bits != bitAllocated)
continue;
}
if(((xbits>>(shift+2))&BitsMask) == BitsDead)
continue; // noscan object
// If buffer is full, get a new one.
if(wbuf == nil || nobj >= nelem(wbuf->obj)) {
if(wbuf != nil)
// Queue the obj for scanning.
PREFETCH(obj);
obj = (byte*)((uintptr)obj & ~(PtrSize-1));
p = scanbuf[scanbufpos];
scanbuf[scanbufpos++] = obj;
if(scanbufpos == nelem(scanbuf))
scanbufpos = 0;
if(p == nil)
continue;
// If workbuf is full, obtain an empty one.
if(nobj >= nelem(wbuf->obj)) {
wbuf->nobj = nobj;
wbuf = getempty(wbuf);
wp = wbuf->obj;
nobj = 0;
nobj = wbuf->nobj;
wp = &wbuf->obj[nobj];
}
*wp = obj;
*wp = p;
wp++;
nobj++;
}
// Save work buffer state
*_wp = wp;
*_wbuf = wbuf;
*_nobj = nobj;
}
static void
enqueue1(Workbuf **wbufp, Obj obj)
{
Workbuf *wbuf;
wbuf = *wbufp;
if(wbuf->nobj >= nelem(wbuf->obj))
*wbufp = wbuf = getempty(wbuf);
wbuf->obj[wbuf->nobj++] = obj;
if(Debug && ptrmask == nil) {
// For heap objects ensure that we did not overscan.
n = 0;
p = nil;
if(!runtime·mlookup(b, &p, &n, nil) || b != p || i > n) {
runtime·printf("runtime: scanned (%p,%p), heap object (%p,%p)\n", b, i, p, n);
runtime·throw("scanblock: scanned invalid object");
}
}
}
}
static void
markroot(ParFor *desc, uint32 i)
{
Workbuf *wbuf;
FinBlock *fb;
MHeap *h;
MSpan **allspans, *s;
......@@ -1222,24 +502,25 @@ markroot(ParFor *desc, uint32 i)
void *p;
USED(&desc);
wbuf = getempty(nil);
// Note: if you add a case here, please also update heapdump.c:dumproots.
switch(i) {
case RootData:
enqueue1(&wbuf, (Obj){data, edata - data, (uintptr)gcdata});
scanblock(data, edata - data, work.gcdata);
//scanblock(data, edata - data, ScanConservatively);
break;
case RootBss:
enqueue1(&wbuf, (Obj){bss, ebss - bss, (uintptr)gcbss});
scanblock(bss, ebss - bss, work.gcbss);
//scanblock(bss, ebss - bss, ScanConservatively);
break;
case RootFinalizers:
for(fb=allfin; fb; fb=fb->alllink)
enqueue1(&wbuf, (Obj){(byte*)fb->fin, fb->cnt*sizeof(fb->fin[0]), 0});
scanblock((byte*)fb->fin, fb->cnt*sizeof(fb->fin[0]), ScanConservatively);
break;
case RootSpanTypes:
// mark span types and MSpan.specials (to walk spans only once)
case RootSpans:
// mark MSpan.specials
h = &runtime·mheap;
sg = h->sweepgen;
allspans = h->allspans;
......@@ -1254,12 +535,6 @@ markroot(ParFor *desc, uint32 i)
runtime·printf("sweep %d %d\n", s->sweepgen, sg);
runtime·throw("gc: unswept span");
}
// The garbage collector ignores type pointers stored in MSpan.types:
// - Compiler-generated types are stored outside of heap.
// - The reflect package has runtime-generated types cached in its data structures.
// The garbage collector relies on finding the references via that cache.
if(s->types.compression == MTypes_Words || s->types.compression == MTypes_Bytes)
markonly((byte*)s->types.data);
for(sp = s->specials; sp != nil; sp = sp->next) {
if(sp->kind != KindSpecialFinalizer)
continue;
......@@ -1268,10 +543,8 @@ markroot(ParFor *desc, uint32 i)
spf = (SpecialFinalizer*)sp;
// A finalizer can be set for an inner byte of an object, find object beginning.
p = (void*)((s->start << PageShift) + spf->offset/s->elemsize*s->elemsize);
enqueue1(&wbuf, (Obj){p, s->elemsize, 0});
enqueue1(&wbuf, (Obj){(void*)&spf->fn, PtrSize, 0});
enqueue1(&wbuf, (Obj){(void*)&spf->fint, PtrSize, 0});
enqueue1(&wbuf, (Obj){(void*)&spf->ot, PtrSize, 0});
scanblock(p, s->elemsize, nil);
scanblock((void*)&spf->fn, PtrSize, ScanConservatively);
}
}
break;
......@@ -1289,13 +562,10 @@ markroot(ParFor *desc, uint32 i)
// needed only to output in traceback
if((gp->status == Gwaiting || gp->status == Gsyscall) && gp->waitsince == 0)
gp->waitsince = work.tstart;
addstackroots(gp, &wbuf);
scanstack(gp);
break;
}
if(wbuf)
scanblock(wbuf, false);
}
// Get an empty work buffer off the work.empty list,
......@@ -1315,9 +585,6 @@ getempty(Workbuf *b)
static void
putempty(Workbuf *b)
{
if(CollectStats)
runtime·xadd64(&gcstats.putempty, 1);
runtime·lfstackpush(&work.empty, &b->node);
}
......@@ -1327,9 +594,6 @@ getfull(Workbuf *b)
{
int32 i;
if(CollectStats)
runtime·xadd64(&gcstats.getfull, 1);
if(b != nil)
runtime·lfstackpush(&work.empty, &b->node);
b = (Workbuf*)runtime·lfstackpop(&work.full);
......@@ -1380,8 +644,6 @@ handoff(Workbuf *b)
return b1;
}
extern byte pclntab[]; // base for f->ptrsoff
BitVector
runtime·stackmapdata(StackMap *stackmap, int32 n)
{
......@@ -1390,138 +652,9 @@ runtime·stackmapdata(StackMap *stackmap, int32 n)
return (BitVector){stackmap->nbit, stackmap->data + n*((stackmap->nbit+31)/32)};
}
// Scans an interface data value when the interface type indicates
// that it is a pointer.
static void
scaninterfacedata(uintptr bits, byte *scanp, void *wbufp)
{
Itab *tab;
Type *type;
if(runtime·precisestack) {
if(bits == BitsIface) {
tab = *(Itab**)scanp;
if(tab->type->size <= sizeof(void*) && (tab->type->kind & KindNoPointers))
return;
} else { // bits == BitsEface
type = *(Type**)scanp;
if(type->size <= sizeof(void*) && (type->kind & KindNoPointers))
return;
}
}
enqueue1(wbufp, (Obj){scanp+PtrSize, PtrSize, 0});
}
// Starting from scanp, scans words corresponding to set bits.
static void
scanbitvector(Func *f, bool precise, byte *scanp, BitVector *bv, void *wbufp)
{
uintptr word, bits;
uint32 *wordp;
int32 i, remptrs;
byte *p;
wordp = bv->data;
for(remptrs = bv->n; remptrs > 0; remptrs -= 32) {
word = *wordp++;
if(remptrs < 32)
i = remptrs;
else
i = 32;
i /= BitsPerPointer;
for(; i > 0; i--) {
bits = word & 3;
switch(bits) {
case BitsDead:
if(runtime·debug.gcdead)
*(uintptr*)scanp = PoisonGC;
break;
case BitsScalar:
break;
case BitsPointer:
p = *(byte**)scanp;
if(p != nil) {
if(Debug > 2)
runtime·printf("frame %s @%p: ptr %p\n", runtime·funcname(f), scanp, p);
if(precise && (p < (byte*)PageSize || (uintptr)p == PoisonGC || (uintptr)p == PoisonStack)) {
// Looks like a junk value in a pointer slot.
// Liveness analysis wrong?
g->m->traceback = 2;
runtime·printf("bad pointer in frame %s at %p: %p\n", runtime·funcname(f), scanp, p);
runtime·throw("bad pointer in scanbitvector");
}
enqueue1(wbufp, (Obj){scanp, PtrSize, 0});
}
break;
case BitsMultiWord:
p = scanp;
word >>= BitsPerPointer;
scanp += PtrSize;
i--;
if(i == 0) {
// Get next chunk of bits
remptrs -= 32;
word = *wordp++;
if(remptrs < 32)
i = remptrs;
else
i = 32;
i /= BitsPerPointer;
}
switch(word & 3) {
case BitsString:
if(Debug > 2)
runtime·printf("frame %s @%p: string %p/%D\n", runtime·funcname(f), p, ((String*)p)->str, (int64)((String*)p)->len);
if(((String*)p)->len != 0)
markonly(((String*)p)->str);
break;
case BitsSlice:
word >>= BitsPerPointer;
scanp += PtrSize;
i--;
if(i == 0) {
// Get next chunk of bits
remptrs -= 32;
word = *wordp++;
if(remptrs < 32)
i = remptrs;
else
i = 32;
i /= BitsPerPointer;
}
if(Debug > 2)
runtime·printf("frame %s @%p: slice %p/%D/%D\n", runtime·funcname(f), p, ((Slice*)p)->array, (int64)((Slice*)p)->len, (int64)((Slice*)p)->cap);
if(((Slice*)p)->cap < ((Slice*)p)->len) {
g->m->traceback = 2;
runtime·printf("bad slice in frame %s at %p: %p/%p/%p\n", runtime·funcname(f), p, ((byte**)p)[0], ((byte**)p)[1], ((byte**)p)[2]);
runtime·throw("slice capacity smaller than length");
}
if(((Slice*)p)->cap != 0)
enqueue1(wbufp, (Obj){p, PtrSize, 0});
break;
case BitsIface:
case BitsEface:
if(*(byte**)p != nil) {
if(Debug > 2) {
if((word&3) == BitsEface)
runtime·printf("frame %s @%p: eface %p %p\n", runtime·funcname(f), p, ((uintptr*)p)[0], ((uintptr*)p)[1]);
else
runtime·printf("frame %s @%p: iface %p %p\n", runtime·funcname(f), p, ((uintptr*)p)[0], ((uintptr*)p)[1]);
}
scaninterfacedata(word & 3, p, wbufp);
}
break;
}
}
word >>= BitsPerPointer;
scanp += PtrSize;
}
}
}
// Scan a stack frame: local variables and function arguments/results.
static bool
scanframe(Stkframe *frame, void *wbufp)
scanframe(Stkframe *frame, void *unused)
{
Func *f;
StackMap *stackmap;
......@@ -1529,8 +662,8 @@ scanframe(Stkframe *frame, void *wbufp)
uintptr size;
uintptr targetpc;
int32 pcdata;
bool precise;
USED(unused);
f = frame->fn;
targetpc = frame->continpc;
if(targetpc == 0) {
......@@ -1549,23 +682,21 @@ scanframe(Stkframe *frame, void *wbufp)
// Scan local variables if stack frame has been allocated.
// Use pointer information if known.
precise = false;
stackmap = runtime·funcdata(f, FUNCDATA_LocalsPointerMaps);
if(stackmap == nil) {
// No locals information, scan everything.
size = frame->varp - (byte*)frame->sp;
if(Debug > 2)
runtime·printf("frame %s unsized locals %p+%p\n", runtime·funcname(f), frame->varp-size, size);
enqueue1(wbufp, (Obj){frame->varp - size, size, 0});
scanblock(frame->varp - size, size, ScanConservatively);
} else if(stackmap->n < 0) {
// Locals size information, scan just the locals.
size = -stackmap->n;
if(Debug > 2)
runtime·printf("frame %s conservative locals %p+%p\n", runtime·funcname(f), frame->varp-size, size);
enqueue1(wbufp, (Obj){frame->varp - size, size, 0});
scanblock(frame->varp - size, size, ScanConservatively);
} else if(stackmap->n > 0) {
// Locals bitmap information, scan just the pointers in
// locals.
// Locals bitmap information, scan just the pointers in locals.
if(pcdata < 0 || pcdata >= stackmap->n) {
// don't know where we are
runtime·printf("pcdata is %d and %d stack map entries for %s (targetpc=%p)\n",
......@@ -1574,8 +705,7 @@ scanframe(Stkframe *frame, void *wbufp)
}
bv = runtime·stackmapdata(stackmap, pcdata);
size = (bv.n * PtrSize) / BitsPerPointer;
precise = true;
scanbitvector(f, true, frame->varp - size, &bv, wbufp);
scanblock(frame->varp - size, bv.n/BitsPerPointer*PtrSize, (byte*)bv.data);
}
// Scan arguments.
......@@ -1583,17 +713,17 @@ scanframe(Stkframe *frame, void *wbufp)
stackmap = runtime·funcdata(f, FUNCDATA_ArgsPointerMaps);
if(stackmap != nil) {
bv = runtime·stackmapdata(stackmap, pcdata);
scanbitvector(f, precise, frame->argp, &bv, wbufp);
scanblock(frame->argp, bv.n/BitsPerPointer*PtrSize, (byte*)bv.data);
} else {
if(Debug > 2)
runtime·printf("frame %s conservative args %p+%p\n", runtime·funcname(f), frame->argp, (uintptr)frame->arglen);
enqueue1(wbufp, (Obj){frame->argp, frame->arglen, 0});
scanblock(frame->argp, frame->arglen, ScanConservatively);
}
return true;
}
static void
addstackroots(G *gp, Workbuf **wbufp)
scanstack(G *gp)
{
M *mp;
int32 n;
......@@ -1639,7 +769,7 @@ addstackroots(G *gp, Workbuf **wbufp)
USED(sp);
USED(stk);
USED(guard);
runtime·gentraceback(~(uintptr)0, ~(uintptr)0, 0, gp, 0, nil, 0x7fffffff, scanframe, wbufp, false);
runtime·gentraceback(~(uintptr)0, ~(uintptr)0, 0, gp, 0, nil, 0x7fffffff, scanframe, nil, false);
} else {
n = 0;
while(stk) {
......@@ -1649,7 +779,7 @@ addstackroots(G *gp, Workbuf **wbufp)
}
if(Debug > 2)
runtime·printf("conservative stack %p+%p\n", (byte*)sp, (uintptr)stk-sp);
enqueue1(wbufp, (Obj){(byte*)sp, (uintptr)stk - sp, (uintptr)defaultProg | PRECISE | LOOP});
scanblock((byte*)sp, (uintptr)stk - sp, ScanConservatively);
sp = stk->gobuf.sp;
guard = stk->stackguard;
stk = (Stktop*)stk->stackbase;
......@@ -1733,16 +863,12 @@ bool
runtime·MSpan_Sweep(MSpan *s)
{
int32 cl, n, npages, nfree;
uintptr size, off, *bitp, shift, bits;
uintptr size, off, *bitp, shift, xbits, bits;
uint32 sweepgen;
byte *p;
MCache *c;
byte *arena_start;
MLink head, *end;
byte *type_data;
byte compression;
uintptr type_data_inc;
MLink *x;
Special *special, **specialp, *y;
bool res, sweepgenset;
......@@ -1772,17 +898,6 @@ runtime·MSpan_Sweep(MSpan *s)
c = g->m->mcache;
sweepgenset = false;
// mark any free objects in this span so we don't collect them
for(x = s->freelist; x != nil; x = x->next) {
// This is markonly(x) but faster because we don't need
// atomic access and we're guaranteed to be pointing at
// the head of a valid object.
off = (uintptr*)x - (uintptr*)runtime·mheap.arena_start;
bitp = (uintptr*)runtime·mheap.arena_start - off/wordsPerBitmapWord - 1;
shift = off % wordsPerBitmapWord;
*bitp |= bitMarked<<shift;
}
// Unlink & free special records for any objects we're about to free.
specialp = &s->specials;
special = *specialp;
......@@ -1791,9 +906,9 @@ runtime·MSpan_Sweep(MSpan *s)
p = (byte*)(s->start << PageShift) + special->offset/size*size;
off = (uintptr*)p - (uintptr*)arena_start;
bitp = (uintptr*)arena_start - off/wordsPerBitmapWord - 1;
shift = off % wordsPerBitmapWord;
bits = *bitp>>shift;
if((bits & (bitAllocated|bitMarked)) == bitAllocated) {
shift = (off % wordsPerBitmapWord) * gcBits;
bits = (*bitp>>shift) & bitMask;
if(bits == bitAllocated) {
// Find the exact byte for which the special was setup
// (as opposed to object beginning).
p = (byte*)(s->start << PageShift) + special->offset;
......@@ -1807,56 +922,52 @@ runtime·MSpan_Sweep(MSpan *s)
}
} else {
// object is still live: keep special record
if(bits != bitMarked) {
runtime·printf("runtime: bad bits for special object %p: %d\n", p, (int32)bits);
runtime·throw("runtime: bad bits for special object");
}
specialp = &special->next;
special = *specialp;
}
}
type_data = (byte*)s->types.data;
type_data_inc = sizeof(uintptr);
compression = s->types.compression;
switch(compression) {
case MTypes_Bytes:
type_data += 8*sizeof(uintptr);
type_data_inc = 1;
break;
}
// Sweep through n objects of given size starting at p.
// This thread owns the span now, so it can manipulate
// the block bitmap without atomic operations.
p = (byte*)(s->start << PageShift);
for(; n > 0; n--, p += size, type_data+=type_data_inc) {
for(; n > 0; n--, p += size) {
off = (uintptr*)p - (uintptr*)arena_start;
bitp = (uintptr*)arena_start - off/wordsPerBitmapWord - 1;
shift = off % wordsPerBitmapWord;
bits = *bitp>>shift;
shift = (off % wordsPerBitmapWord) * gcBits;
xbits = *bitp;
bits = (xbits>>shift) & bitMask;
if((bits & bitAllocated) == 0)
// Non-allocated or FlagNoGC object, ignore.
if(bits == bitBoundary)
continue;
if((bits & bitMarked) != 0) {
*bitp &= ~(bitMarked<<shift);
// Allocated and marked object, reset bits to allocated.
if(bits == bitMarked) {
*bitp = (xbits & ~(bitMarked<<shift)) | (bitAllocated<<shift);
continue;
}
// At this point we know that we are looking at garbage object
// that needs to be collected.
if(runtime·debug.allocfreetrace)
runtime·tracefree(p, size);
// Clear mark and scan bits.
*bitp &= ~((bitScan|bitMarked)<<shift);
// Reset to boundary.
*bitp = (xbits & ~(bitAllocated<<shift)) | (bitBoundary<<shift);
if(cl == 0) {
// Free large span.
runtime·unmarkspan(p, 1<<PageShift);
runtime·unmarkspan(p, s->npages<<PageShift);
s->needzero = 1;
// important to set sweepgen before returning it to heap
runtime·atomicstore(&s->sweepgen, sweepgen);
sweepgenset = true;
// See note about SysFault vs SysFree in malloc.goc.
if(runtime·debug.efence)
if(runtime·debug.efence) {
s->limit = nil; // prevent mlookup from finding this span
runtime·SysFault(p, size);
else
} else
runtime·MHeap_Free(&runtime·mheap, s, 1);
c->local_nlargefree++;
c->local_largefree += size;
......@@ -1864,14 +975,6 @@ runtime·MSpan_Sweep(MSpan *s)
res = true;
} else {
// Free small object.
switch(compression) {
case MTypes_Words:
*(uintptr*)type_data = 0;
break;
case MTypes_Bytes:
*(byte*)type_data = 0;
break;
}
if(size > 2*sizeof(uintptr))
((uintptr*)p)[1] = (uintptr)0xdeaddeaddeaddeadll; // mark as "needs to be zeroed"
else if(size > sizeof(uintptr))
......@@ -1904,7 +1007,7 @@ runtime·MSpan_Sweep(MSpan *s)
c->local_cachealloc -= nfree * size;
runtime·xadd64(&mstats.next_gc, -(uint64)(nfree * size * (gcpercent + 100)/100));
res = runtime·MCentral_FreeSpan(&runtime·mheap.central[cl], s, nfree, head.next, end);
//MCentral_FreeSpan updates sweepgen
// MCentral_FreeSpan updates sweepgen
}
return res;
}
......@@ -1919,6 +1022,9 @@ static struct
MSpan** spans;
uint32 nspan;
uint32 spanidx;
uint32 nbgsweep;
uint32 npausesweep;
} sweep;
// background sweeping goroutine
......@@ -1928,7 +1034,7 @@ bgsweep(void)
g->issystem = 1;
for(;;) {
while(runtime·sweepone() != -1) {
gcstats.nbgsweep++;
sweep.nbgsweep++;
runtime·gosched();
}
runtime·lock(&gclock);
......@@ -1982,80 +1088,6 @@ runtime·sweepone(void)
}
}
static void
dumpspan(uint32 idx)
{
int32 sizeclass, n, npages, i, column;
uintptr size;
byte *p;
byte *arena_start;
MSpan *s;
bool allocated;
s = runtime·mheap.allspans[idx];
if(s->state != MSpanInUse)
return;
arena_start = runtime·mheap.arena_start;
p = (byte*)(s->start << PageShift);
sizeclass = s->sizeclass;
size = s->elemsize;
if(sizeclass == 0) {
n = 1;
} else {
npages = runtime·class_to_allocnpages[sizeclass];
n = (npages << PageShift) / size;
}
runtime·printf("%p .. %p:\n", p, p+n*size);
column = 0;
for(; n>0; n--, p+=size) {
uintptr off, *bitp, shift, bits;
off = (uintptr*)p - (uintptr*)arena_start;
bitp = (uintptr*)arena_start - off/wordsPerBitmapWord - 1;
shift = off % wordsPerBitmapWord;
bits = *bitp>>shift;
allocated = ((bits & bitAllocated) != 0);
for(i=0; i<size; i+=sizeof(void*)) {
if(column == 0) {
runtime·printf("\t");
}
if(i == 0) {
runtime·printf(allocated ? "(" : "[");
runtime·printf("%p: ", p+i);
} else {
runtime·printf(" ");
}
runtime·printf("%p", *(void**)(p+i));
if(i+sizeof(void*) >= size) {
runtime·printf(allocated ? ") " : "] ");
}
column++;
if(column == 8) {
runtime·printf("\n");
column = 0;
}
}
}
runtime·printf("\n");
}
// A debugging function to dump the contents of memory
void
runtime·memorydump(void)
{
uint32 spanidx;
for(spanidx=0; spanidx<runtime·mheap.nspan; spanidx++) {
dumpspan(spanidx);
}
}
void
runtime·gchelper(void)
{
......@@ -2068,9 +1100,8 @@ runtime·gchelper(void)
runtime·parfordo(work.markfor);
// help other threads scan secondary blocks
scanblock(nil, true);
scanblock(nil, 0, nil);
bufferList[g->m->helpgc].busy = 0;
nproc = work.nproc; // work.nproc can change right after we increment work.ndone
if(runtime·xadd(&work.ndone, +1) == nproc-1)
runtime·notewakeup(&work.alldone);
......@@ -2235,6 +1266,8 @@ runtime·gc(int32 force)
runtime·throw("runtime: gc work buffer is misaligned");
if((((uintptr)&work.full) & 7) != 0)
runtime·throw("runtime: gc work buffer is misaligned");
if(sizeof(Workbuf) != WorkbufSize)
runtime·throw("runtime: size of Workbuf is suboptimal");
// The gc is turned off (via enablegc) until
// the bootstrap has completed.
......@@ -2314,31 +1347,32 @@ static void
gc(struct gc_args *args)
{
int64 t0, t1, t2, t3, t4;
uint64 heap0, heap1, obj, ninstr;
uint64 heap0, heap1, obj;
GCStats stats;
uint32 i;
Eface eface;
if(runtime·debug.allocfreetrace)
runtime·tracegc();
// This is required while we explicitly free objects and have imprecise GC.
// If we don't do this, then scanblock can queue an object for scanning;
// then another thread frees this object during RootFlushCaches;
// then the first thread scans the object; then debug check in scanblock
// finds this object already freed and throws.
if(Debug)
flushallmcaches();
g->m->traceback = 2;
t0 = args->start_time;
work.tstart = args->start_time;
if(CollectStats)
runtime·memclr((byte*)&gcstats, sizeof(gcstats));
if(work.gcdata == nil) {
work.gcdata = unrollglobgcprog(gcdata, edata - data);
work.gcbss = unrollglobgcprog(gcbss, ebss - bss);
}
g->m->locks++; // disable gc during mallocs in parforalloc
if(work.markfor == nil)
work.markfor = runtime·parforalloc(MaxGcproc);
g->m->locks--;
if(itabtype == nil) {
// get C pointer to the Go type "itab"
runtime·gc_itab_ptr(&eface);
itabtype = ((PtrType*)eface.type)->elem;
}
t1 = 0;
if(runtime·debug.gctrace)
......@@ -2346,7 +1380,7 @@ gc(struct gc_args *args)
// Sweep what is not sweeped by bgsweep.
while(runtime·sweepone() != -1)
gcstats.npausesweep++;
sweep.npausesweep++;
work.nwait = 0;
work.ndone = 0;
......@@ -2363,13 +1397,12 @@ gc(struct gc_args *args)
gchelperstart();
runtime·parfordo(work.markfor);
scanblock(nil, true);
scanblock(nil, 0, nil);
t3 = 0;
if(runtime·debug.gctrace)
t3 = runtime·nanotime();
bufferList[g->m->helpgc].busy = 0;
if(work.nproc > 1)
runtime·notesleep(&work.alldone);
......@@ -2408,35 +1441,11 @@ gc(struct gc_args *args)
mstats.numgc, work.nproc, (t1-t0)/1000, (t2-t1)/1000, (t3-t2)/1000, (t4-t3)/1000,
heap0>>20, heap1>>20, obj,
mstats.nmalloc, mstats.nfree,
sweep.nspan, gcstats.nbgsweep, gcstats.npausesweep,
sweep.nspan, sweep.nbgsweep, sweep.npausesweep,
stats.nhandoff, stats.nhandoffcnt,
work.markfor->nsteal, work.markfor->nstealcnt,
stats.nprocyield, stats.nosyield, stats.nsleep);
gcstats.nbgsweep = gcstats.npausesweep = 0;
if(CollectStats) {
runtime·printf("scan: %D bytes, %D objects, %D untyped, %D types from MSpan\n",
gcstats.nbytes, gcstats.obj.cnt, gcstats.obj.notype, gcstats.obj.typelookup);
if(gcstats.ptr.cnt != 0)
runtime·printf("avg ptrbufsize: %D (%D/%D)\n",
gcstats.ptr.sum/gcstats.ptr.cnt, gcstats.ptr.sum, gcstats.ptr.cnt);
if(gcstats.obj.cnt != 0)
runtime·printf("avg nobj: %D (%D/%D)\n",
gcstats.obj.sum/gcstats.obj.cnt, gcstats.obj.sum, gcstats.obj.cnt);
runtime·printf("rescans: %D, %D bytes\n", gcstats.rescan, gcstats.rescanbytes);
runtime·printf("instruction counts:\n");
ninstr = 0;
for(i=0; i<nelem(gcstats.instr); i++) {
runtime·printf("\t%d:\t%D\n", i, gcstats.instr[i]);
ninstr += gcstats.instr[i];
}
runtime·printf("\ttotal:\t%D\n", ninstr);
runtime·printf("putempty: %D, getfull: %D\n", gcstats.putempty, gcstats.getfull);
runtime·printf("markonly base lookup: bit %D word %D span %D\n", gcstats.markonly.foundbit, gcstats.markonly.foundword, gcstats.markonly.foundspan);
runtime·printf("flushptrbuf base lookup: bit %D word %D span %D\n", gcstats.flushptrbuf.foundbit, gcstats.flushptrbuf.foundword, gcstats.flushptrbuf.foundspan);
}
sweep.nbgsweep = sweep.npausesweep = 0;
}
// We cache current runtime·mheap.allspans array in sweep.spans,
......@@ -2468,7 +1477,7 @@ gc(struct gc_args *args)
} else {
// Sweep all spans eagerly.
while(runtime·sweepone() != -1)
gcstats.npausesweep++;
sweep.npausesweep++;
}
// Shrink a stack if not much of it is being used.
......@@ -2560,8 +1569,6 @@ gchelperstart(void)
{
if(g->m->helpgc < 0 || g->m->helpgc >= MaxGcproc)
runtime·throw("gchelperstart: bad m->helpgc");
if(runtime·xchg(&bufferList[g->m->helpgc].busy, 1))
runtime·throw("gchelperstart: already busy");
if(g != g->m->g0)
runtime·throw("gchelper not running on g0 stack");
}
......@@ -2698,102 +1705,289 @@ runtime·wakefing(void)
return res;
}
void
runtime·marknogc(void *v)
// Recursively GC program in prog.
// mask is where to store the result.
// ppos is a pointer to position in mask, in bits.
// sparse says to generate 4-bits per word mask for heap (2-bits for data/bss otherwise).
static byte*
unrollgcprog1(byte *mask, byte *prog, uintptr *ppos, bool inplace, bool sparse)
{
uintptr *b, off, shift;
uintptr *b, off, shift, pos, siz, i;
byte *arena_start, *prog1, v;
off = (uintptr*)v - (uintptr*)runtime·mheap.arena_start; // word offset
b = (uintptr*)runtime·mheap.arena_start - off/wordsPerBitmapWord - 1;
shift = off % wordsPerBitmapWord;
*b = (*b & ~(bitAllocated<<shift)) | bitBlockBoundary<<shift;
arena_start = runtime·mheap.arena_start;
pos = *ppos;
for(;;) {
switch(prog[0]) {
case insData:
prog++;
siz = prog[0];
prog++;
for(i = 0; i < siz; i++) {
v = prog[i/PointersPerByte];
v >>= (i%PointersPerByte)*BitsPerPointer;
v &= BitsMask;
if(inplace) {
// Store directly into GC bitmap.
off = (uintptr*)(mask+pos) - (uintptr*)arena_start;
b = (uintptr*)arena_start - off/wordsPerBitmapWord - 1;
shift = (off % wordsPerBitmapWord) * gcBits;
if((shift%8)==0)
((byte*)b)[shift/8] = 0;
((byte*)b)[shift/8] |= v<<((shift%8)+2);
pos += PtrSize;
} else if(sparse) {
// 4-bits per word
v <<= (pos%8)+2;
mask[pos/8] |= v;
pos += gcBits;
} else {
// 2-bits per word
v <<= pos%8;
mask[pos/8] |= v;
pos += BitsPerPointer;
}
}
prog += ROUND(siz*BitsPerPointer, 8)/8;
break;
case insArray:
prog++;
siz = 0;
for(i = 0; i < PtrSize; i++)
siz = (siz<<8) + prog[PtrSize-i-1];
prog += PtrSize;
prog1 = nil;
for(i = 0; i < siz; i++)
prog1 = unrollgcprog1(mask, prog, &pos, inplace, sparse);
if(prog1[0] != insArrayEnd)
runtime·throw("unrollgcprog: array does not end with insArrayEnd");
prog = prog1+1;
break;
case insArrayEnd:
case insEnd:
*ppos = pos;
return prog;
default:
runtime·throw("unrollgcprog: unknown instruction");
}
}
}
// Unrolls GC program prog for data/bss, returns dense GC mask.
static byte*
unrollglobgcprog(byte *prog, uintptr size)
{
byte *mask;
uintptr pos, masksize;
masksize = ROUND(ROUND(size, PtrSize)/PtrSize*BitsPerPointer, 8)/8;
mask = runtime·persistentalloc(masksize+1, 0, &mstats.gc_sys);
mask[masksize] = 0xa1;
pos = 0;
prog = unrollgcprog1(mask, prog, &pos, false, false);
if(pos != size/PtrSize*BitsPerPointer) {
runtime·printf("unrollglobgcprog: bad program size, got %D, expect %D\n",
(uint64)pos, (uint64)size/PtrSize*BitsPerPointer);
runtime·throw("unrollglobgcprog: bad program size");
}
if(prog[0] != insEnd)
runtime·throw("unrollglobgcprog: program does not end with insEnd");
if(mask[masksize] != 0xa1)
runtime·throw("unrollglobgcprog: overflow");
return mask;
}
static void
unrollgcproginplace(void *v, uintptr size, uintptr size0, Type *typ)
{
uintptr *b, off, shift, pos;
byte *arena_start, *prog;
pos = 0;
prog = (byte*)typ->gc[1];
while(pos != size0)
unrollgcprog1(v, prog, &pos, true, true);
// Mark first word as bitAllocated.
arena_start = runtime·mheap.arena_start;
off = (uintptr*)v - (uintptr*)arena_start;
b = (uintptr*)arena_start - off/wordsPerBitmapWord - 1;
shift = (off % wordsPerBitmapWord) * gcBits;
*b |= bitAllocated<<shift;
// Mark word after last as BitsDead.
if(size0 < size) {
off = (uintptr*)((byte*)v + size0) - (uintptr*)arena_start;
b = (uintptr*)arena_start - off/wordsPerBitmapWord - 1;
shift = (off % wordsPerBitmapWord) * gcBits;
*b &= ~(bitPtrMask<<shift) | (BitsDead<<(shift+2));
}
}
// Unrolls GC program in typ->gc[1] into typ->gc[0]
static void
unrollgcprog(Type *typ)
{
static Lock lock;
byte *mask, *prog;
uintptr pos;
uint32 x;
runtime·lock(&lock);
mask = (byte*)typ->gc[0];
if(mask[0] == 0) {
pos = 8; // skip the unroll flag
prog = (byte*)typ->gc[1];
prog = unrollgcprog1(mask, prog, &pos, false, true);
if(prog[0] != insEnd)
runtime·throw("unrollgcprog: program does not end with insEnd");
if(((typ->size/PtrSize)%2) != 0) {
// repeat the program twice
prog = (byte*)typ->gc[1];
unrollgcprog1(mask, prog, &pos, false, true);
}
// atomic way to say mask[0] = 1
x = ((uint32*)mask)[0];
runtime·atomicstore((uint32*)mask, x|1);
}
runtime·unlock(&lock);
}
void
runtime·markscan(void *v)
runtime·markallocated(void *v, uintptr size, uintptr size0, Type *typ, bool scan)
{
uintptr *b, off, shift;
uintptr *b, off, shift, i, ti, te, nptr, masksize;
byte *arena_start, x;
bool *ptrmask;
off = (uintptr*)v - (uintptr*)runtime·mheap.arena_start; // word offset
b = (uintptr*)runtime·mheap.arena_start - off/wordsPerBitmapWord - 1;
shift = off % wordsPerBitmapWord;
*b |= bitScan<<shift;
arena_start = runtime·mheap.arena_start;
off = (uintptr*)v - (uintptr*)arena_start;
b = (uintptr*)arena_start - off/wordsPerBitmapWord - 1;
shift = (off % wordsPerBitmapWord) * gcBits;
if(Debug && (((*b)>>shift)&bitMask) != bitBoundary) {
runtime·printf("runtime: bad bits in markallocated (%p) b=%p[%p]\n", v, b, *b);
runtime·throw("bad bits in markallocated");
}
if(!scan) {
// BitsDead in the first quadruple means don't scan.
if(size == PtrSize)
*b = (*b & ~((bitBoundary|bitPtrMask)<<shift)) | ((bitAllocated+(BitsDead<<2))<<shift);
else
((byte*)b)[shift/8] = bitAllocated+(BitsDead<<2);
return;
}
if(size == PtrSize) {
// It's one word and it has pointers, it must be a pointer.
*b = (*b & ~((bitBoundary|bitPtrMask)<<shift)) | ((bitAllocated | (BitsPointer<<2))<<shift);
return;
}
ti = te = 0;
ptrmask = nil;
if(typ != nil && (typ->gc[0]|typ->gc[1]) != 0 && typ->size > PtrSize) {
if(typ->kind&KindGCProg) {
nptr = ROUND(typ->size, PtrSize)/PtrSize;
masksize = nptr;
if(masksize%2)
masksize *= 2; // repeated twice
masksize = masksize*PointersPerByte/8; // 4 bits per word
masksize++; // unroll flag in the beginning
if(masksize > MaxGCMask && typ->gc[1] != 0) {
// If the mask is too large, unroll the program directly
// into the GC bitmap. It's 7 times slower than copying
// from the pre-unrolled mask, but saves 1/16 of type size
// memory for the mask.
unrollgcproginplace(v, size, size0, typ);
return;
}
ptrmask = (byte*)typ->gc[0];
// check whether the program is already unrolled
if((runtime·atomicload((uint32*)ptrmask)&0xff) == 0)
unrollgcprog(typ);
ptrmask++; // skip the unroll flag byte
} else
ptrmask = (byte*)&typ->gc[0]; // embed mask
if(size == 2*PtrSize) {
((byte*)b)[shift/8] = ptrmask[0] | bitAllocated;
return;
}
te = typ->size/PtrSize;
// if the type occupies odd number of words, its mask is repeated twice
if((te%2) == 0)
te /= 2;
}
if(size == 2*PtrSize) {
((byte*)b)[shift/8] = (BitsPointer<<2) | (BitsPointer<<6) | bitAllocated;
return;
}
// Copy pointer bitmask into the bitmap.
for(i=0; i<size0; i+=2*PtrSize) {
x = (BitsPointer<<2) | (BitsPointer<<6);
if(ptrmask != nil) {
x = ptrmask[ti++];
if(ti == te)
ti = 0;
}
off = (uintptr*)((byte*)v + i) - (uintptr*)arena_start;
b = (uintptr*)arena_start - off/wordsPerBitmapWord - 1;
shift = (off % wordsPerBitmapWord) * gcBits;
if(i == 0)
x |= bitAllocated;
if(i+PtrSize == size0)
x &= ~(bitPtrMask<<4);
((byte*)b)[shift/8] = x;
}
if(size0 == i && size0 < size) {
// mark the word after last object's word as BitsDead
off = (uintptr*)((byte*)v + size0) - (uintptr*)arena_start;
b = (uintptr*)arena_start - off/wordsPerBitmapWord - 1;
shift = (off % wordsPerBitmapWord) * gcBits;
((byte*)b)[shift/8] = 0;
}
}
// mark the block at v as freed.
void
runtime·markfreed(void *v)
{
uintptr *b, off, shift, xbits;
if(0)
runtime·printf("markfreed %p\n", v);
uintptr *b, off, shift, xbits, bits;
if((byte*)v > (byte*)runtime·mheap.arena_used || (byte*)v < runtime·mheap.arena_start)
runtime·throw("markfreed: bad pointer");
off = (uintptr*)v - (uintptr*)runtime·mheap.arena_start; // word offset
b = (uintptr*)runtime·mheap.arena_start - off/wordsPerBitmapWord - 1;
shift = off % wordsPerBitmapWord;
shift = (off % wordsPerBitmapWord) * gcBits;
xbits = *b;
bits = (xbits>>shift) & bitMask;
if(bits == bitMiddle)
runtime·throw("bad bits in markfreed");
if(bits == bitBoundary)
return; // FlagNoGC object
if(!g->m->gcing || work.nproc == 1) {
// During normal operation (not GC), the span bitmap is not updated concurrently,
// because either the span is cached or accesses are protected with MCentral lock.
*b = (*b & ~(bitMask<<shift)) | (bitAllocated<<shift);
*b = (xbits & ~(bitMask<<shift)) | (bitBoundary<<shift);
} else {
// During GC other threads concurrently mark heap.
for(;;) {
xbits = *b;
if(runtime·casp((void**)b, (void*)xbits, (void*)((xbits & ~(bitMask<<shift)) | (bitAllocated<<shift))))
if(runtime·casp((void**)b, (void*)xbits, (void*)((xbits & ~(bitMask<<shift)) | (bitBoundary<<shift))))
break;
}
}
}
// check that the block at v of size n is marked freed.
void
runtime·checkfreed(void *v, uintptr n)
{
uintptr *b, bits, off, shift;
if(!runtime·checking)
return;
if((byte*)v+n > (byte*)runtime·mheap.arena_used || (byte*)v < runtime·mheap.arena_start)
return; // not allocated, so okay
off = (uintptr*)v - (uintptr*)runtime·mheap.arena_start; // word offset
b = (uintptr*)runtime·mheap.arena_start - off/wordsPerBitmapWord - 1;
shift = off % wordsPerBitmapWord;
bits = *b>>shift;
if((bits & bitAllocated) != 0) {
runtime·printf("checkfreed %p+%p: off=%p have=%p\n",
v, n, off, bits & bitMask);
runtime·throw("checkfreed: not freed");
}
}
// mark the span of memory at v as having n blocks of the given size.
// if leftover is true, there is left over space at the end of the span.
void
runtime·markspan(void *v, uintptr size, uintptr n, bool leftover)
{
uintptr *b, *b0, off, shift, i, x;
uintptr *b, *b0, off, shift, x;
byte *p;
if((byte*)v+size*n > (byte*)runtime·mheap.arena_used || (byte*)v < runtime·mheap.arena_start)
runtime·throw("markspan: bad pointer");
if(runtime·checking) {
// bits should be all zero at the start
off = (byte*)v + size - runtime·mheap.arena_start;
b = (uintptr*)(runtime·mheap.arena_start - off/wordsPerBitmapWord);
for(i = 0; i < size/PtrSize/wordsPerBitmapWord; i++) {
if(b[i] != 0)
runtime·throw("markspan: span bits not zero");
}
}
p = v;
if(leftover) // mark a boundary just past end of last block too
n++;
......@@ -2807,14 +2001,14 @@ runtime·markspan(void *v, uintptr size, uintptr n, bool leftover)
// bitmap words.
off = (uintptr*)p - (uintptr*)runtime·mheap.arena_start; // word offset
b = (uintptr*)runtime·mheap.arena_start - off/wordsPerBitmapWord - 1;
shift = off % wordsPerBitmapWord;
shift = (off % wordsPerBitmapWord) * gcBits;
if(b0 != b) {
if(b0 != nil)
*b0 = x;
b0 = b;
x = 0;
}
x |= bitAllocated<<shift;
x |= bitBoundary<<shift;
}
*b0 = x;
}
......@@ -2830,7 +2024,7 @@ runtime·unmarkspan(void *v, uintptr n)
p = v;
off = p - (uintptr*)runtime·mheap.arena_start; // word offset
if(off % wordsPerBitmapWord != 0)
if((off % wordsPerBitmapWord) != 0)
runtime·throw("markspan: unaligned pointer");
b = (uintptr*)runtime·mheap.arena_start - off/wordsPerBitmapWord - 1;
n /= PtrSize;
......@@ -2865,3 +2059,101 @@ runtime·MHeap_MapBits(MHeap *h)
runtime·SysMap(h->arena_start - n, n - h->bitmap_mapped, h->arena_reserved, &mstats.gc_sys);
h->bitmap_mapped = n;
}
static bool
getgcmaskcb(Stkframe *frame, void *ctxt)
{
Stkframe *frame0;
frame0 = ctxt;
if(frame0->sp >= (uintptr)frame->varp - frame->sp && frame0->sp < (uintptr)frame->varp) {
*frame0 = *frame;
return false;
}
return true;
}
// Returns GC type info for object p for testing.
void
runtime·getgcmask(byte *p, Type *t, byte **mask, uintptr *len)
{
Stkframe frame;
uintptr i, n, off, bits, shift, *b;
byte *base;
*mask = nil;
*len = 0;
// data
if(p >= data && p < edata) {
n = ((PtrType*)t)->elem->size;
*len = n/PtrSize;
*mask = runtime·mallocgc(*len, nil, 0);
for(i = 0; i < n; i += PtrSize) {
off = (p+i-data)/PtrSize;
bits = (work.gcdata[off/PointersPerByte] >> ((off%PointersPerByte)*BitsPerPointer))&BitsMask;
(*mask)[i/PtrSize] = bits;
}
return;
}
// bss
if(p >= bss && p < ebss) {
n = ((PtrType*)t)->elem->size;
*len = n/PtrSize;
*mask = runtime·mallocgc(*len, nil, 0);
for(i = 0; i < n; i += PtrSize) {
off = (p+i-bss)/PtrSize;
bits = (work.gcbss[off/PointersPerByte] >> ((off%PointersPerByte)*BitsPerPointer))&BitsMask;
(*mask)[i/PtrSize] = bits;
}
return;
}
// heap
if(runtime·mlookup(p, &base, &n, nil)) {
*len = n/PtrSize;
*mask = runtime·mallocgc(*len, nil, 0);
for(i = 0; i < n; i += PtrSize) {
off = (uintptr*)(base+i) - (uintptr*)runtime·mheap.arena_start;
b = (uintptr*)runtime·mheap.arena_start - off/wordsPerBitmapWord - 1;
shift = (off % wordsPerBitmapWord) * gcBits;
bits = (*b >> (shift+2))&BitsMask;
(*mask)[i/PtrSize] = bits;
}
return;
}
// stack
frame.fn = nil;
frame.sp = (uintptr)p;
runtime·gentraceback((uintptr)runtime·getcallerpc(&p), (uintptr)runtime·getcallersp(&p), 0, g, 0, nil, 1000, getgcmaskcb, &frame, false);
if(frame.fn != nil) {
Func *f;
StackMap *stackmap;
BitVector bv;
uintptr size;
uintptr targetpc;
int32 pcdata;
f = frame.fn;
targetpc = frame.continpc;
if(targetpc == 0)
return;
if(targetpc != f->entry)
targetpc--;
pcdata = runtime·pcdatavalue(f, PCDATA_StackMapIndex, targetpc);
if(pcdata == -1)
return;
stackmap = runtime·funcdata(f, FUNCDATA_LocalsPointerMaps);
if(stackmap == nil || stackmap->n <= 0)
return;
bv = runtime·stackmapdata(stackmap, pcdata);
size = bv.n/BitsPerPointer*PtrSize;
n = ((PtrType*)t)->elem->size;
*len = n/PtrSize;
*mask = runtime·mallocgc(*len, nil, 0);
for(i = 0; i < n; i += PtrSize) {
off = (p+i-frame.varp+size)/PtrSize;
bits = (bv.data[off/PointersPerByte] >> ((off%PointersPerByte)*BitsPerPointer))&BitsMask;
(*mask)[i/PtrSize] = bits;
}
}
}
src/pkg/runtime/mgc0.h
View file @ cd17a717
......@@ -4,84 +4,76 @@
// Garbage collector (GC)
// GC instruction opcodes.
//
// The opcode of an instruction is followed by zero or more
// arguments to the instruction.
//
// Meaning of arguments:
// off Offset (in bytes) from the start of the current object
// objgc Pointer to GC info of an object
// objgcrel Offset to GC info of an object
// len Length of an array
// elemsize Size (in bytes) of an element
// size Size (in bytes)
//
// NOTE: There is a copy of these in ../reflect/type.go.
// They must be kept in sync.
enum {
GC_END, // End of object, loop or subroutine. Args: none
GC_PTR, // A typed pointer. Args: (off, objgc)
GC_APTR, // Pointer to an arbitrary object. Args: (off)
GC_ARRAY_START, // Start an array with a fixed length. Args: (off, len, elemsize)
GC_ARRAY_NEXT, // The next element of an array. Args: none
GC_CALL, // Call a subroutine. Args: (off, objgcrel)
GC_CHAN_PTR, // Go channel. Args: (off, ChanType*)
GC_STRING, // Go string. Args: (off)
GC_EFACE, // interface{}. Args: (off)
GC_IFACE, // interface{...}. Args: (off)
GC_SLICE, // Go slice. Args: (off, objgc)
GC_REGION, // A region/part of the current object. Args: (off, size, objgc)
ScanStackByFrames = 1,
GC_NUM_INSTR, // Number of instruction opcodes
};
// Four bits per word (see #defines below).
wordsPerBitmapWord = sizeof(void*)*8/4,
gcBits = 4,
enum {
// Size of GC's fixed stack.
// GC type info programs.
// The programs allow to store type info required for GC in a compact form.
// Most importantly arrays take O(1) space instead of O(n).
// The program grammar is:
//
// The current GC implementation permits:
// - at most 1 stack allocation because of GC_CALL
// - at most GC_STACK_CAPACITY allocations because of GC_ARRAY_START
GC_STACK_CAPACITY = 8,
};
// Program = {Block} "insEnd"
// Block = Data | Array
// Data = "insData" DataSize DataBlock
// DataSize = int // size of the DataBlock in bit pairs, 1 byte
// DataBlock = binary // dense GC mask (2 bits per word) of size ]DataSize/4[ bytes
// Array = "insArray" ArrayLen Block "insArrayEnd"
// ArrayLen = int // length of the array, 8 bytes (4 bytes for 32-bit arch)
//
// Each instruction (insData, insArray, etc) is 1 byte.
// For example, for type struct { x []byte; y [20]struct{ z int; w *byte }; }
// the program looks as:
//
// insData 3 (BitsMultiWord BitsSlice BitsScalar)
// insArray 20 insData 2 (BitsScalar BitsPointer) insArrayEnd insEnd
//
// Total size of the program is 17 bytes (13 bytes on 32-bits).
// The corresponding GC mask would take 43 bytes (it would be repeated
// because the type has odd number of words).
insData = 1,
insArray,
insArrayEnd,
insEnd,
enum {
ScanStackByFrames = 1,
IgnorePreciseGC = 0,
// Pointer map
BitsPerPointer = 2,
BitsMask = (1<<BitsPerPointer)-1,
PointersPerByte = 8/BitsPerPointer,
// Four bits per word (see #defines below).
wordsPerBitmapWord = sizeof(void*)*8/4,
bitShift = sizeof(void*)*8/4,
BitsDead = 0,
BitsScalar = 1,
BitsPointer = 2,
BitsMultiWord = 3,
// BitsMultiWord will be set for the first word of a multi-word item.
// When it is set, one of the following will be set for the second word.
BitsString = 0,
BitsSlice = 1,
BitsIface = 2,
BitsEface = 3,
MaxGCMask = 0, // disabled because wastes several bytes of memory
};
// Bits in per-word bitmap.
// #defines because enum might not be able to hold the values.
// #defines because we shift the values beyond 32 bits.
//
// Each word in the bitmap describes wordsPerBitmapWord words
// of heap memory. There are 4 bitmap bits dedicated to each heap word,
// so on a 64-bit system there is one bitmap word per 16 heap words.
// The bits in the word are packed together by type first, then by
// heap location, so each 64-bit bitmap word consists of, from top to bottom,
// the 16 bitMarked bits for the corresponding heap words,
// then the 16 bitScan/bitBlockBoundary bits, then the 16 bitAllocated bits.
// This layout makes it easier to iterate over the bits of a given type.
//
// The bitmap starts at mheap.arena_start and extends *backward* from
// there. On a 64-bit system the off'th word in the arena is tracked by
// the off/16+1'th word before mheap.arena_start. (On a 32-bit system,
// the only difference is that the divisor is 8.)
//
// To pull out the bits corresponding to a given pointer p, we use:
//
// off = p - (uintptr*)mheap.arena_start; // word offset
// b = (uintptr*)mheap.arena_start - off/wordsPerBitmapWord - 1;
// shift = off % wordsPerBitmapWord
// bits = *b >> shift;
// /* then test bits & bitAllocated, bits & bitMarked, etc. */
//
#define bitAllocated ((uintptr)1<<(bitShift*0)) /* block start; eligible for garbage collection */
#define bitScan ((uintptr)1<<(bitShift*1)) /* when bitAllocated is set */
#define bitMarked ((uintptr)1<<(bitShift*2)) /* when bitAllocated is set */
#define bitBlockBoundary ((uintptr)1<<(bitShift*1)) /* when bitAllocated is NOT set - mark for FlagNoGC objects */
#define bitMask (bitAllocated | bitScan | bitMarked)
#define bitMiddle ((uintptr)0) // middle of an object
#define bitBoundary ((uintptr)1) // boundary on a non-allocated object
#define bitAllocated ((uintptr)2) // boundary on an allocated object
#define bitMarked ((uintptr)3) // boundary on an allocated and marked object
#define bitMask ((uintptr)bitMiddle|bitBoundary|bitAllocated|bitMarked)
#define bitPtrMask ((uintptr)BitsMask<<2)
src/pkg/runtime/mheap.c
View file @ cd17a717
......@@ -195,7 +195,6 @@ mheap_alloc(MHeap *h, uintptr npage, int32 sizeclass, bool large)
s->ref = 0;
s->sizeclass = sizeclass;
s->elemsize = (sizeclass==0 ? s->npages<<PageShift : runtime·class_to_size[sizeclass]);
s->types.compression = MTypes_Empty;
// update stats, sweep lists
if(large) {
......@@ -468,7 +467,6 @@ mheap_free(MHeap *h, MSpan *s, int32 acct)
mstats.heap_alloc -= s->npages<<PageShift;
mstats.heap_objects--;
}
s->types.compression = MTypes_Empty;
MHeap_FreeSpanLocked(h, s);
runtime·unlock(h);
}
......@@ -713,7 +711,6 @@ runtime·MSpan_Init(MSpan *span, PageID start, uintptr npages)
span->state = MSpanDead;
span->unusedsince = 0;
span->npreleased = 0;
span->types.compression = MTypes_Empty;
span->specialLock.key = 0;
span->specials = nil;
span->needzero = 0;
......
src/pkg/runtime/mprof.goc
View file @ cd17a717
......@@ -409,33 +409,15 @@ func GoroutineProfile(b Slice) (n int, ok bool) {
static Lock tracelock;
static int8*
typeinfoname(int32 typeinfo)
{
if(typeinfo == TypeInfo_SingleObject)
return "single object";
else if(typeinfo == TypeInfo_Array)
return "array";
else if(typeinfo == TypeInfo_Chan)
return "channel";
runtime·throw("typinfoname: unknown type info");
return nil;
}
void
runtime·tracealloc(void *p, uintptr size, uintptr typ)
runtime·tracealloc(void *p, uintptr size, Type *type)
{
int8 *name;
Type *type;
runtime·lock(&tracelock);
g->m->traceback = 2;
type = (Type*)(typ & ~3);
name = typeinfoname(typ & 3);
if(type == nil)
runtime·printf("tracealloc(%p, %p, %s)\n", p, size, name);
runtime·printf("tracealloc(%p, %p)\n", p, size);
else
runtime·printf("tracealloc(%p, %p, %s of %S)\n", p, size, name, *type->string);
runtime·printf("tracealloc(%p, %p, %S)\n", p, size, *type->string);
if(g->m->curg == nil || g == g->m->curg) {
runtime·goroutineheader(g);
runtime·traceback((uintptr)runtime·getcallerpc(&p), (uintptr)runtime·getcallersp(&p), 0, g);
......
src/pkg/runtime/proc.c
View file @ cd17a717
......@@ -9,6 +9,7 @@
#include "stack.h"
#include "race.h"
#include "type.h"
#include "mgc0.h"
#include "../../cmd/ld/textflag.h"
// Goroutine scheduler
......
src/pkg/runtime/race.c
View file @ cd17a717
......@@ -152,7 +152,7 @@ runtime·racewriteobjectpc(void *addr, Type *t, void *callpc, void *pc)
{
uint8 kind;
kind = t->kind & ~KindNoPointers;
kind = t->kind & KindMask;
if(kind == KindArray || kind == KindStruct)
runtime·racewriterangepc(addr, t->size, callpc, pc);
else
......@@ -164,7 +164,7 @@ runtime·racereadobjectpc(void *addr, Type *t, void *callpc, void *pc)
{
uint8 kind;
kind = t->kind & ~KindNoPointers;
kind = t->kind & KindMask;
if(kind == KindArray || kind == KindStruct)
runtime·racereadrangepc(addr, t->size, callpc, pc);
else
......
src/pkg/runtime/runtime.h
View file @ cd17a717
......@@ -756,7 +756,6 @@ extern int32 runtime·ncpu;
extern bool runtime·iscgo;
extern void (*runtime·sysargs)(int32, uint8**);
extern uintptr runtime·maxstring;
extern uint32 runtime·Hchansize;
extern uint32 runtime·cpuid_ecx;
extern uint32 runtime·cpuid_edx;
extern DebugVars runtime·debug;
......
src/pkg/runtime/slice.goc
View file @ cd17a717
......@@ -126,7 +126,7 @@ growslice1(SliceType *t, Slice x, intgo newcap, Slice *ret)
// Can't use FlagNoZero w/o FlagNoScan, because otherwise GC can scan unitialized memory.
if(typ->kind&KindNoPointers)
flag = FlagNoScan|FlagNoZero;
ret->array = runtime·mallocgc(capmem, (uintptr)typ|TypeInfo_Array, flag);
ret->array = runtime·mallocgc(capmem, typ, flag);
ret->len = x.len;
ret->cap = newcap1;
lenmem = x.len*typ->size;
......
src/pkg/runtime/stack.c
View file @ cd17a717
......@@ -10,6 +10,7 @@
#include "typekind.h"
#include "type.h"
#include "race.h"
#include "mgc0.h"
#include "../../cmd/ld/textflag.h"
enum
......
src/pkg/runtime/type.go
View file @ cd17a717
......@@ -22,7 +22,7 @@ type rtype struct {
fieldAlign uint8
kind uint8
alg unsafe.Pointer
gc unsafe.Pointer
gc [2]unsafe.Pointer
string *string
*uncommonType
ptrToThis *rtype
......
src/pkg/runtime/type.h
View file @ cd17a717
......@@ -16,7 +16,8 @@ typedef struct IMethod IMethod;
typedef struct SliceType SliceType;
typedef struct FuncType FuncType;
// Needs to be in sync with ../../cmd/ld/decodesym.c:/^commonsize
// Needs to be in sync with ../../cmd/ld/decodesym.c:/^commonsize,
// pkg/reflect/type.go:/type anf type.go:/rtype
struct Type
{
uintptr size;
......@@ -26,7 +27,17 @@ struct Type
uint8 fieldAlign;
uint8 kind;
Alg *alg;
void *gc;
// gc stores type info required for garbage collector.
// If (kind&KindGCProg)==0, then gc directly contains sparse GC bitmap
// (no indirection), 4 bits per word.
// If (kind&KindGCProg)!=0, then gc[1] points to a compiler-generated
// read-only GC program; and gc[0] points to BSS space for sparse GC bitmap.
// For huge types (>MaxGCMask), runtime unrolls the program directly into
// GC bitmap and gc[0] is not used. For moderately-sized types, runtime
// unrolls the program into gc[0] space on first use. The first byte of gc[0]
// (gc[0][0]) contains 'unroll' flag saying whether the program is already
// unrolled into gc[0] or not.
uintptr gc[2];
String *string;
UncommonType *x;
Type *ptrto;
......
src/pkg/runtime/typekind.h
View file @ cd17a717
......@@ -33,6 +33,8 @@ enum {
KindStruct,
KindUnsafePointer,
KindGCProg = 1<<6, // Type.gc points to GC program
KindNoPointers = 1<<7,
KindMask = (1<<6)-1,
};
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