--- /dev/null
+// 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.
+
+// Implementation of runtime/debug.WriteHeapDump. Writes all
+// objects in the heap plus additional info (roots, threads,
+// finalizers, etc.) to a file.
+
+// The format of the dumped file is described at
+// http://code.google.com/p/go-wiki/wiki/heapdump13
+
+#include "runtime.h"
+#include "arch_GOARCH.h"
+#include "malloc.h"
+#include "mgc0.h"
+#include "type.h"
+#include "typekind.h"
+#include "funcdata.h"
+#include "zaexperiment.h"
+
+extern byte data[];
+extern byte edata[];
+extern byte bss[];
+extern byte ebss[];
+extern byte gcdata[];
+extern byte gcbss[];
+
+enum {
+ FieldKindEol = 0,
+ FieldKindPtr = 1,
+ FieldKindString = 2,
+ FieldKindSlice = 3,
+ FieldKindIface = 4,
+ FieldKindEface = 5,
+
+ TagEOF = 0,
+ TagObject = 1,
+ TagOtherRoot = 2,
+ TagType = 3,
+ TagGoRoutine = 4,
+ TagStackFrame = 5,
+ TagParams = 6,
+ TagFinalizer = 7,
+ TagItab = 8,
+ TagOSThread = 9,
+ TagMemStats = 10,
+ TagQueuedFinalizer = 11,
+ TagData = 12,
+ TagBss = 13,
+ TagDefer = 14,
+ TagPanic = 15,
+
+ 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 dumpbvtypes(BitVector *bv, byte *base);
+
+// fd to write the dump to.
+static uintptr dumpfd;
+
+// buffer of pending write data
+enum {
+ BufSize = 4096,
+};
+static byte buf[BufSize];
+static uintptr nbuf;
+
+static void
+write(byte *data, uintptr len)
+{
+ if(len + nbuf <= BufSize) {
+ runtime·memmove(buf + nbuf, data, len);
+ nbuf += len;
+ return;
+ }
+ runtime·write(dumpfd, buf, nbuf);
+ if(len >= BufSize) {
+ runtime·write(dumpfd, data, len);
+ nbuf = 0;
+ } else {
+ runtime·memmove(buf, data, len);
+ nbuf = len;
+ }
+}
+
+static void
+flush(void)
+{
+ runtime·write(dumpfd, buf, nbuf);
+ nbuf = 0;
+}
+
+// Cache of types that have been serialized already.
+// We use a type's hash field to pick a bucket.
+// Inside a bucket, we keep a list of types that
+// have been serialized so far, most recently used first.
+// Note: when a bucket overflows we may end up
+// serializing a type more than once. That's ok.
+enum {
+ TypeCacheBuckets = 256, // must be a power of 2
+ TypeCacheAssoc = 4,
+};
+typedef struct TypeCacheBucket TypeCacheBucket;
+struct TypeCacheBucket {
+ Type *t[TypeCacheAssoc];
+};
+static TypeCacheBucket typecache[TypeCacheBuckets];
+
+// dump a uint64 in a varint format parseable by encoding/binary
+static void
+dumpint(uint64 v)
+{
+ byte buf[10];
+ int32 n;
+ n = 0;
+ while(v >= 0x80) {
+ buf[n++] = v | 0x80;
+ v >>= 7;
+ }
+ buf[n++] = v;
+ write(buf, n);
+}
+
+static void
+dumpbool(bool b)
+{
+ dumpint(b ? 1 : 0);
+}
+
+// dump varint uint64 length followed by memory contents
+static void
+dumpmemrange(byte *data, uintptr len)
+{
+ dumpint(len);
+ write(data, len);
+}
+
+static void
+dumpstr(String s)
+{
+ dumpmemrange(s.str, s.len);
+}
+
+static void
+dumpcstr(int8 *c)
+{
+ dumpmemrange((byte*)c, runtime·findnull((byte*)c));
+}
+
+// dump information for a type
+static void
+dumptype(Type *t)
+{
+ TypeCacheBucket *b;
+ int32 i, j;
+
+ if(t == nil) {
+ return;
+ }
+
+ // If we've definitely serialized the type before,
+ // no need to do it again.
+ b = &typecache[t->hash & (TypeCacheBuckets-1)];
+ if(t == b->t[0]) return;
+ for(i = 1; i < TypeCacheAssoc; i++) {
+ if(t == b->t[i]) {
+ // Move-to-front
+ for(j = i; j > 0; j--) {
+ b->t[j] = b->t[j-1];
+ }
+ b->t[0] = t;
+ return;
+ }
+ }
+ // Might not have been dumped yet. Dump it and
+ // remember we did so.
+ for(j = TypeCacheAssoc-1; j > 0; j--) {
+ b->t[j] = b->t[j-1];
+ }
+ b->t[0] = t;
+
+ // dump the type
+ dumpint(TagType);
+ dumpint((uintptr)t);
+ dumpint(t->size);
+ dumpstr(*t->string);
+ 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;
+}
+
+// dump an object
+static void
+dumpobj(byte *obj, uintptr size, Type *type, uintptr kind)
+{
+ if(type != nil) {
+ dumptype(type);
+ dumpefacetypes(obj, size, type, kind);
+ }
+
+ dumpint(TagObject);
+ dumpint((uintptr)obj);
+ dumpint((uintptr)type);
+ dumpint(kind);
+ dumpmemrange(obj, size);
+}
+
+static void
+dumpotherroot(int8 *description, byte *to)
+{
+ dumpint(TagOtherRoot);
+ dumpcstr(description);
+ dumpint((uintptr)to);
+}
+
+static void
+dumpfinalizer(byte *obj, FuncVal *fn, Type* fint, PtrType *ot)
+{
+ dumpint(TagFinalizer);
+ dumpint((uintptr)obj);
+ dumpint((uintptr)fn);
+ dumpint((uintptr)fn->fn);
+ dumpint((uintptr)fint);
+ dumpint((uintptr)ot);
+}
+
+typedef struct ChildInfo ChildInfo;
+struct ChildInfo {
+ // Information passed up from the callee frame about
+ // the layout of the outargs region.
+ uintptr argoff; // where the arguments start in the frame
+ uintptr arglen; // size of args region
+ BitVector *args; // if not nil, pointer map of args region
+
+ byte *sp; // callee sp
+ uintptr depth; // depth in call stack (0 == most recent)
+};
+
+// dump kinds & offsets of interesting fields in bv
+static void
+dumpbv(BitVector *bv, uintptr offset)
+{
+ uintptr i;
+
+ for(i = 0; i < bv->n; i += BitsPerPointer) {
+ switch(bv->data[i/32] >> i%32 & 3) {
+ case BitsDead:
+ case BitsScalar:
+ break;
+ case BitsPointer:
+ dumpint(FieldKindPtr);
+ dumpint(offset + i / BitsPerPointer * PtrSize);
+ break;
+ case BitsMultiWord:
+ switch(bv->data[(i+BitsPerPointer)/32] >> (i+BitsPerPointer)%32 & 3) {
+ case BitsString:
+ dumpint(FieldKindString);
+ dumpint(offset + i / BitsPerPointer * PtrSize);
+ i += BitsPerPointer;
+ break;
+ case BitsSlice:
+ dumpint(FieldKindSlice);
+ dumpint(offset + i / BitsPerPointer * PtrSize);
+ i += 2 * BitsPerPointer;
+ break;
+ case BitsIface:
+ dumpint(FieldKindIface);
+ dumpint(offset + i / BitsPerPointer * PtrSize);
+ i += BitsPerPointer;
+ break;
+ case BitsEface:
+ dumpint(FieldKindEface);
+ dumpint(offset + i / BitsPerPointer * PtrSize);
+ i += BitsPerPointer;
+ break;
+ }
+ }
+ }
+}
+
+static bool
+dumpframe(Stkframe *s, void *arg)
+{
+ Func *f;
+ ChildInfo *child;
+ uintptr pc, off, size;
+ int32 pcdata;
+ StackMap *stackmap;
+ int8 *name;
+ BitVector *bv;
+
+ child = (ChildInfo*)arg;
+ f = s->fn;
+
+ // Figure out what we can about our stack map
+ pc = s->pc;
+ if(pc != f->entry)
+ pc--;
+ pcdata = runtime·pcdatavalue(f, PCDATA_StackMapIndex, pc);
+ if(pcdata == -1) {
+ // We do not have a valid pcdata value but there might be a
+ // stackmap for this function. It is likely that we are looking
+ // at the function prologue, assume so and hope for the best.
+ pcdata = 0;
+ }
+ stackmap = runtime·funcdata(f, FUNCDATA_LocalsPointerMaps);
+
+ // Dump any types we will need to resolve Efaces.
+ if(child->args != nil)
+ dumpbvtypes(child->args, (byte*)s->sp + child->argoff);
+ if(stackmap != nil && stackmap->n > 0) {
+ bv = runtime·stackmapdata(stackmap, pcdata);
+ dumpbvtypes(bv, s->varp - bv->n / BitsPerPointer * PtrSize);
+ } else {
+ bv = nil;
+ }
+
+ // Dump main body of stack frame.
+ dumpint(TagStackFrame);
+ dumpint(s->sp); // lowest address in frame
+ dumpint(child->depth); // # of frames deep on the stack
+ dumpint((uintptr)child->sp); // sp of child, or 0 if bottom of stack
+ dumpmemrange((byte*)s->sp, s->fp - s->sp); // frame contents
+ dumpint(f->entry);
+ dumpint(s->pc);
+ name = runtime·funcname(f);
+ if(name == nil)
+ name = "unknown function";
+ dumpcstr(name);
+
+ // Dump fields in the outargs section
+ if(child->args != nil) {
+ dumpbv(child->args, child->argoff);
+ } else {
+ // conservative - everything might be a pointer
+ for(off = child->argoff; off < child->argoff + child->arglen; off += PtrSize) {
+ dumpint(FieldKindPtr);
+ dumpint(off);
+ }
+ }
+
+ // Dump fields in the local vars section
+ if(stackmap == nil) {
+ // No locals information, dump everything.
+ for(off = child->arglen; off < s->varp - (byte*)s->sp; off += PtrSize) {
+ dumpint(FieldKindPtr);
+ dumpint(off);
+ }
+ } else if(stackmap->n < 0) {
+ // Locals size information, dump just the locals.
+ size = -stackmap->n;
+ for(off = s->varp - size - (byte*)s->sp; off < s->varp - (byte*)s->sp; off += PtrSize) {
+ dumpint(FieldKindPtr);
+ dumpint(off);
+ }
+ } else if(stackmap->n > 0) {
+ // Locals bitmap information, scan just the pointers in
+ // locals.
+ dumpbv(bv, s->varp - bv->n / BitsPerPointer * PtrSize - (byte*)s->sp);
+ }
+ dumpint(FieldKindEol);
+
+ // Record arg info for parent.
+ child->argoff = s->argp - (byte*)s->sp;
+ child->arglen = s->arglen;
+ child->sp = (byte*)s->sp;
+ child->depth++;
+ stackmap = runtime·funcdata(f, FUNCDATA_ArgsPointerMaps);
+ if(stackmap != nil)
+ child->args = runtime·stackmapdata(stackmap, pcdata);
+ else
+ child->args = nil;
+ return true;
+}
+
+static void
+dumpgoroutine(G *gp)
+{
+ uintptr sp, pc, lr;
+ ChildInfo child;
+ Defer *d;
+ Panic *p;
+
+ if(gp->syscallstack != (uintptr)nil) {
+ sp = gp->syscallsp;
+ pc = gp->syscallpc;
+ lr = 0;
+ } else {
+ sp = gp->sched.sp;
+ pc = gp->sched.pc;
+ lr = gp->sched.lr;
+ }
+
+ dumpint(TagGoRoutine);
+ dumpint((uintptr)gp);
+ dumpint((uintptr)sp);
+ dumpint(gp->goid);
+ dumpint(gp->gopc);
+ dumpint(gp->status);
+ dumpbool(gp->issystem);
+ dumpbool(gp->isbackground);
+ dumpint(gp->waitsince);
+ dumpcstr(gp->waitreason);
+ dumpint((uintptr)gp->sched.ctxt);
+ dumpint((uintptr)gp->m);
+ dumpint((uintptr)gp->defer);
+ dumpint((uintptr)gp->panic);
+
+ // dump stack
+ child.args = nil;
+ child.arglen = 0;
+ child.sp = nil;
+ child.depth = 0;
+ if(!ScanStackByFrames)
+ runtime·throw("need frame info to dump stacks");
+ runtime·gentraceback(pc, sp, lr, gp, 0, nil, 0x7fffffff, dumpframe, &child, false);
+
+ // dump defer & panic records
+ for(d = gp->defer; d != nil; d = d->link) {
+ dumpint(TagDefer);
+ dumpint((uintptr)d);
+ dumpint((uintptr)gp);
+ dumpint((uintptr)d->argp);
+ dumpint((uintptr)d->pc);
+ dumpint((uintptr)d->fn);
+ dumpint((uintptr)d->fn->fn);
+ dumpint((uintptr)d->link);
+ }
+ for (p = gp->panic; p != nil; p = p->link) {
+ dumpint(TagPanic);
+ dumpint((uintptr)p);
+ dumpint((uintptr)gp);
+ dumpint((uintptr)p->arg.type);
+ dumpint((uintptr)p->arg.data);
+ dumpint((uintptr)p->defer);
+ dumpint((uintptr)p->link);
+ }
+}
+
+static void
+dumpgs(void)
+{
+ G *gp;
+ uint32 i;
+
+ // goroutines & stacks
+ for(i = 0; i < runtime·allglen; i++) {
+ gp = runtime·allg[i];
+ switch(gp->status){
+ default:
+ runtime·printf("unexpected G.status %d\n", gp->status);
+ runtime·throw("mark - bad status");
+ case Gdead:
+ break;
+ case Grunnable:
+ case Gsyscall:
+ case Gwaiting:
+ dumpgoroutine(gp);
+ break;
+ }
+ }
+}
+
+static void
+finq_callback(FuncVal *fn, byte *obj, uintptr nret, Type *fint, PtrType *ot)
+{
+ dumpint(TagQueuedFinalizer);
+ dumpint((uintptr)obj);
+ dumpint((uintptr)fn);
+ dumpint((uintptr)fn->fn);
+ dumpint((uintptr)fint);
+ dumpint((uintptr)ot);
+ USED(&nret);
+}
+
+
+static void
+dumproots(void)
+{
+ MSpan *s, **allspans;
+ uint32 spanidx;
+ Special *sp;
+ SpecialFinalizer *spf;
+ byte *p;
+
+ // data segment
+ dumpint(TagData);
+ dumpint((uintptr)data);
+ dumpmemrange(data, edata - data);
+ dumpfields((uintptr*)gcdata + 1);
+
+ // bss segment
+ dumpint(TagBss);
+ dumpint((uintptr)bss);
+ dumpmemrange(bss, ebss - bss);
+ dumpfields((uintptr*)gcbss + 1);
+
+ // 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)
+ continue;
+ spf = (SpecialFinalizer*)sp;
+ p = (byte*)((s->start << PageShift) + spf->offset);
+ dumpfinalizer(p, spf->fn, spf->fint, spf->ot);
+ }
+ }
+ }
+
+ // Finalizer queue
+ 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;
+ MSpan *s;
+ MLink *l;
+ byte *p;
+ Type *t;
+
+ for(i = 0; i < runtime·mheap.nspan; i++) {
+ s = runtime·mheap.allspans[i];
+ if(s->state != MSpanInUse)
+ continue;
+ runtime·MSpan_EnsureSwept(s);
+ 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;
+
+ // Skip FlagNoGC allocations (stacks)
+ if((bits & bitAllocated) == 0)
+ 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);
+ }
+ }
+}
+
+static void
+dumpparams(void)
+{
+ byte *x;
+
+ dumpint(TagParams);
+ x = (byte*)1;
+ if(*(byte*)&x == 1)
+ dumpbool(false); // little-endian ptrs
+ 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);
+ dumpcstr(GOEXPERIMENT);
+ dumpint(runtime·ncpu);
+}
+
+static void
+itab_callback(Itab *tab)
+{
+ Type *t;
+
+ dumpint(TagItab);
+ dumpint((uintptr)tab);
+ t = tab->type;
+ dumpbool(t->size > PtrSize || (t->kind & KindNoPointers) == 0);
+}
+
+static void
+dumpitabs(void)
+{
+ runtime·iterate_itabs(itab_callback);
+}
+
+static void
+dumpms(void)
+{
+ M *mp;
+
+ for(mp = runtime·allm; mp != nil; mp = mp->alllink) {
+ dumpint(TagOSThread);
+ dumpint((uintptr)mp);
+ dumpint(mp->id);
+ dumpint(mp->procid);
+ }
+}
+
+static void
+dumpmemstats(void)
+{
+ int32 i;
+
+ dumpint(TagMemStats);
+ dumpint(mstats.alloc);
+ dumpint(mstats.total_alloc);
+ dumpint(mstats.sys);
+ dumpint(mstats.nlookup);
+ dumpint(mstats.nmalloc);
+ dumpint(mstats.nfree);
+ dumpint(mstats.heap_alloc);
+ dumpint(mstats.heap_sys);
+ dumpint(mstats.heap_idle);
+ dumpint(mstats.heap_inuse);
+ dumpint(mstats.heap_released);
+ dumpint(mstats.heap_objects);
+ dumpint(mstats.stacks_inuse);
+ dumpint(mstats.stacks_sys);
+ dumpint(mstats.mspan_inuse);
+ dumpint(mstats.mspan_sys);
+ dumpint(mstats.mcache_inuse);
+ dumpint(mstats.mcache_sys);
+ dumpint(mstats.buckhash_sys);
+ dumpint(mstats.gc_sys);
+ dumpint(mstats.other_sys);
+ dumpint(mstats.next_gc);
+ dumpint(mstats.last_gc);
+ dumpint(mstats.pause_total_ns);
+ for(i = 0; i < 256; i++)
+ dumpint(mstats.pause_ns[i]);
+ dumpint(mstats.numgc);
+}
+
+static void
+mdump(G *gp)
+{
+ byte *hdr;
+
+ runtime·memclr((byte*)&typecache[0], sizeof(typecache));
+ hdr = (byte*)"go1.3 heap dump\n";
+ write(hdr, runtime·findnull(hdr));
+ dumpparams();
+ dumpitabs();
+ dumpobjs();
+ dumpgs();
+ dumpms();
+ dumproots();
+ dumpmemstats();
+ dumpint(TagEOF);
+ flush();
+
+ gp->param = nil;
+ gp->status = Grunning;
+ runtime·gogo(&gp->sched);
+}
+
+void
+runtime∕debug·WriteHeapDump(uintptr fd)
+{
+ // Stop the world.
+ runtime·semacquire(&runtime·worldsema, false);
+ m->gcing = 1;
+ m->locks++;
+ runtime·stoptheworld();
+
+ // Update stats so we can dump them.
+ // As a side effect, flushes all the MCaches so the MSpan.freelist
+ // lists contain all the free objects.
+ runtime·updatememstats(nil);
+
+ // Set dump file.
+ dumpfd = fd;
+
+ // Call dump routine on M stack.
+ g->status = Gwaiting;
+ g->waitreason = "dumping heap";
+ runtime·mcall(mdump);
+
+ // Reset dump file.
+ dumpfd = 0;
+
+ // Start up the world again.
+ m->gcing = 0;
+ runtime·semrelease(&runtime·worldsema);
+ runtime·starttheworld();
+ 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", 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)
+{
+ playgcprog(0, prog, dump_callback, nil);
+ 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; i += type->size)
+ playgcprog(i, (uintptr*)type->gc + 1, dumpeface_callback, obj);
+ break;
+ case TypeInfo_Chan:
+ for(i = runtime·Hchansize; i < size; i += type->size)
+ playgcprog(i, (uintptr*)type->gc + 1, dumpeface_callback, obj);
+ break;
+ }
+}
+
+// Dump all the types that appear in the type field of
+// any Eface described by this bit vector.
+static void
+dumpbvtypes(BitVector *bv, byte *base)
+{
+ uintptr i;
+
+ for(i = 0; i < bv->n; i += BitsPerPointer) {
+ if((bv->data[i/32] >> i%32 & 3) != BitsMultiWord)
+ continue;
+ switch(bv->data[(i+BitsPerPointer)/32] >> (i+BitsPerPointer)%32 & 3) {
+ case BitsString:
+ case BitsIface:
+ i += BitsPerPointer;
+ break;
+ case BitsSlice:
+ i += 2 * BitsPerPointer;
+ break;
+ case BitsEface:
+ dumptype(*(Type**)(base + i / BitsPerPointer * PtrSize));
+ i += BitsPerPointer;
+ break;
+ }
+ }
+}