mirror of
https://github.com/golang/go
synced 2024-10-04 20:21:22 -06:00
4f2e382c9f
The schedtrace value sets dump period in milliseconds. In default mode the trace looks as follows: SCHED 0ms: gomaxprocs=4 idleprocs=0 threads=3 idlethreads=0 runqueue=0 [1 0 0 0] SCHED 1001ms: gomaxprocs=4 idleprocs=3 threads=6 idlethreads=3 runqueue=0 [0 0 0 0] SCHED 2008ms: gomaxprocs=4 idleprocs=1 threads=6 idlethreads=1 runqueue=0 [0 1 0 0] If GODEBUG=scheddetail=1 is set as well, then the detailed trace is printed: SCHED 0ms: gomaxprocs=4 idleprocs=0 threads=3 idlethreads=0 runqueue=0 singleproc=0 gcwaiting=1 mlocked=0 nmspinning=0 stopwait=0 sysmonwait=0 P0: status=3 tick=1 m=0 runqsize=1/128 gfreecnt=0 P1: status=3 tick=0 m=-1 runqsize=0/128 gfreecnt=0 P2: status=3 tick=0 m=-1 runqsize=0/128 gfreecnt=0 P3: status=3 tick=0 m=-1 runqsize=0/128 gfreecnt=0 M2: p=-1 curg=-1 mallocing=0 throwing=0 gcing=0 locks=1 dying=0 helpgc=0 spinning=0 lockedg=-1 M1: p=-1 curg=-1 mallocing=0 throwing=0 gcing=0 locks=1 dying=0 helpgc=0 spinning=0 lockedg=-1 M0: p=0 curg=1 mallocing=0 throwing=0 gcing=0 locks=1 dying=0 helpgc=0 spinning=0 lockedg=1 G1: status=2() m=0 lockedm=0 G2: status=1() m=-1 lockedm=-1 R=golang-dev, raggi, rsc CC=golang-dev https://golang.org/cl/11435044
527 lines
14 KiB
C
527 lines
14 KiB
C
// Copyright 2012 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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#include "runtime.h"
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#include "arch_GOARCH.h"
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#include "stack.h"
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#include "malloc.h"
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#include "../../cmd/ld/textflag.h"
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// Code related to defer, panic and recover.
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uint32 runtime·panicking;
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static Lock paniclk;
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enum
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{
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DeferChunkSize = 2048
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};
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// Allocate a Defer, usually as part of the larger frame of deferred functions.
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// Each defer must be released with both popdefer and freedefer.
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static Defer*
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newdefer(int32 siz)
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{
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int32 total;
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DeferChunk *c;
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Defer *d;
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c = g->dchunk;
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total = sizeof(*d) + ROUND(siz, sizeof(uintptr)) - sizeof(d->args);
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if(c == nil || total > DeferChunkSize - c->off) {
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if(total > DeferChunkSize / 2) {
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// Not worth putting in any chunk.
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// Allocate a separate block.
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d = runtime·malloc(total);
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d->siz = siz;
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d->special = 1;
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d->free = 1;
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d->link = g->defer;
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g->defer = d;
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return d;
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}
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// Cannot fit in current chunk.
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// Switch to next chunk, allocating if necessary.
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c = g->dchunknext;
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if(c == nil)
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c = runtime·malloc(DeferChunkSize);
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c->prev = g->dchunk;
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c->off = sizeof(*c);
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g->dchunk = c;
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g->dchunknext = nil;
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}
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d = (Defer*)((byte*)c + c->off);
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c->off += total;
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d->siz = siz;
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d->special = 0;
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d->free = 0;
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d->link = g->defer;
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g->defer = d;
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return d;
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}
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// Pop the current defer from the defer stack.
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// Its contents are still valid until the goroutine begins executing again.
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// In particular it is safe to call reflect.call(d->fn, d->argp, d->siz) after
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// popdefer returns.
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static void
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popdefer(void)
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{
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Defer *d;
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DeferChunk *c;
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int32 total;
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d = g->defer;
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if(d == nil)
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runtime·throw("runtime: popdefer nil");
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g->defer = d->link;
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if(d->special) {
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// Nothing else to do.
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return;
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}
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total = sizeof(*d) + ROUND(d->siz, sizeof(uintptr)) - sizeof(d->args);
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c = g->dchunk;
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if(c == nil || (byte*)d+total != (byte*)c+c->off)
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runtime·throw("runtime: popdefer phase error");
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c->off -= total;
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if(c->off == sizeof(*c)) {
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// Chunk now empty, so pop from stack.
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// Save in dchunknext both to help with pingponging between frames
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// and to make sure d is still valid on return.
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if(g->dchunknext != nil)
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runtime·free(g->dchunknext);
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g->dchunknext = c;
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g->dchunk = c->prev;
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}
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}
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// Free the given defer.
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// For defers in the per-goroutine chunk this just clears the saved arguments.
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// For large defers allocated on the heap, this frees them.
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// The defer cannot be used after this call.
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static void
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freedefer(Defer *d)
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{
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int32 total;
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if(d->special) {
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if(d->free)
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runtime·free(d);
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} else {
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// Wipe out any possible pointers in argp/pc/fn/args.
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total = sizeof(*d) + ROUND(d->siz, sizeof(uintptr)) - sizeof(d->args);
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runtime·memclr((byte*)d, total);
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}
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}
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// Create a new deferred function fn with siz bytes of arguments.
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// The compiler turns a defer statement into a call to this.
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// Cannot split the stack because it assumes that the arguments
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// are available sequentially after &fn; they would not be
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// copied if a stack split occurred. It's OK for this to call
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// functions that split the stack.
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#pragma textflag NOSPLIT
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uintptr
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runtime·deferproc(int32 siz, FuncVal *fn, ...)
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{
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Defer *d;
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d = newdefer(siz);
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d->fn = fn;
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d->pc = runtime·getcallerpc(&siz);
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if(thechar == '5')
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d->argp = (byte*)(&fn+2); // skip caller's saved link register
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else
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d->argp = (byte*)(&fn+1);
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runtime·memmove(d->args, d->argp, d->siz);
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// deferproc returns 0 normally.
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// a deferred func that stops a panic
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// makes the deferproc return 1.
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// the code the compiler generates always
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// checks the return value and jumps to the
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// end of the function if deferproc returns != 0.
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return 0;
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}
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// Run a deferred function if there is one.
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// The compiler inserts a call to this at the end of any
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// function which calls defer.
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// If there is a deferred function, this will call runtime·jmpdefer,
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// which will jump to the deferred function such that it appears
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// to have been called by the caller of deferreturn at the point
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// just before deferreturn was called. The effect is that deferreturn
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// is called again and again until there are no more deferred functions.
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// Cannot split the stack because we reuse the caller's frame to
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// call the deferred function.
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//
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// The ... in the prototype keeps the compiler from declaring
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// an argument frame size. deferreturn is a very special function,
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// and if the runtime ever asks for its frame size, that means
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// the traceback routines are probably broken.
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#pragma textflag NOSPLIT
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void
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runtime·deferreturn(uintptr arg0, ...)
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{
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Defer *d;
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byte *argp;
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FuncVal *fn;
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d = g->defer;
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if(d == nil)
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return;
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argp = (byte*)&arg0;
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if(d->argp != argp)
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return;
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// Moving arguments around.
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// Do not allow preemption here, because the garbage collector
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// won't know the form of the arguments until the jmpdefer can
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// flip the PC over to fn.
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m->locks++;
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runtime·memmove(argp, d->args, d->siz);
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fn = d->fn;
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popdefer();
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freedefer(d);
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m->locks--;
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if(m->locks == 0 && g->preempt)
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g->stackguard0 = StackPreempt;
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runtime·jmpdefer(fn, argp);
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}
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// Run all deferred functions for the current goroutine.
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static void
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rundefer(void)
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{
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Defer *d;
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while((d = g->defer) != nil) {
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popdefer();
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reflect·call(d->fn, (byte*)d->args, d->siz);
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freedefer(d);
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}
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}
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// Print all currently active panics. Used when crashing.
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static void
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printpanics(Panic *p)
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{
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if(p->link) {
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printpanics(p->link);
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runtime·printf("\t");
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}
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runtime·printf("panic: ");
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runtime·printany(p->arg);
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if(p->recovered)
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runtime·printf(" [recovered]");
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runtime·printf("\n");
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}
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static void recovery(G*);
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// The implementation of the predeclared function panic.
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void
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runtime·panic(Eface e)
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{
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Defer *d;
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Panic *p;
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void *pc, *argp;
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p = runtime·mal(sizeof *p);
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p->arg = e;
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p->link = g->panic;
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p->stackbase = g->stackbase;
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g->panic = p;
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for(;;) {
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d = g->defer;
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if(d == nil)
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break;
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// take defer off list in case of recursive panic
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popdefer();
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g->ispanic = true; // rock for newstack, where reflect.newstackcall ends up
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argp = d->argp;
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pc = d->pc;
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runtime·newstackcall(d->fn, (byte*)d->args, d->siz);
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freedefer(d);
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if(p->recovered) {
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g->panic = p->link;
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if(g->panic == nil) // must be done with signal
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g->sig = 0;
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runtime·free(p);
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// Pass information about recovering frame to recovery.
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g->sigcode0 = (uintptr)argp;
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g->sigcode1 = (uintptr)pc;
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runtime·mcall(recovery);
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runtime·throw("recovery failed"); // mcall should not return
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}
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}
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// ran out of deferred calls - old-school panic now
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runtime·startpanic();
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printpanics(g->panic);
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runtime·dopanic(0);
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}
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// Unwind the stack after a deferred function calls recover
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// after a panic. Then arrange to continue running as though
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// the caller of the deferred function returned normally.
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static void
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recovery(G *gp)
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{
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void *argp;
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uintptr pc;
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// Info about defer passed in G struct.
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argp = (void*)gp->sigcode0;
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pc = (uintptr)gp->sigcode1;
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// Unwind to the stack frame with d's arguments in it.
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runtime·unwindstack(gp, argp);
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// Make the deferproc for this d return again,
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// this time returning 1. The calling function will
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// jump to the standard return epilogue.
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// The -2*sizeof(uintptr) makes up for the
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// two extra words that are on the stack at
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// each call to deferproc.
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// (The pc we're returning to does pop pop
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// before it tests the return value.)
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// On the arm there are 2 saved LRs mixed in too.
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if(thechar == '5')
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gp->sched.sp = (uintptr)argp - 4*sizeof(uintptr);
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else
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gp->sched.sp = (uintptr)argp - 2*sizeof(uintptr);
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gp->sched.pc = pc;
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gp->sched.lr = 0;
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gp->sched.ret = 1;
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runtime·gogo(&gp->sched);
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}
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// Free stack frames until we hit the last one
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// or until we find the one that contains the sp.
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void
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runtime·unwindstack(G *gp, byte *sp)
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{
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Stktop *top;
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byte *stk;
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// Must be called from a different goroutine, usually m->g0.
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if(g == gp)
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runtime·throw("unwindstack on self");
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while((top = (Stktop*)gp->stackbase) != 0 && top->stackbase != 0) {
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stk = (byte*)gp->stackguard - StackGuard;
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if(stk <= sp && sp < (byte*)gp->stackbase)
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break;
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gp->stackbase = top->stackbase;
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gp->stackguard = top->stackguard;
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gp->stackguard0 = gp->stackguard;
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if(top->free != 0)
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runtime·stackfree(stk, top->free);
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}
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if(sp != nil && (sp < (byte*)gp->stackguard - StackGuard || (byte*)gp->stackbase < sp)) {
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runtime·printf("recover: %p not in [%p, %p]\n", sp, gp->stackguard - StackGuard, gp->stackbase);
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runtime·throw("bad unwindstack");
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}
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}
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// The implementation of the predeclared function recover.
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// Cannot split the stack because it needs to reliably
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// find the stack segment of its caller.
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#pragma textflag NOSPLIT
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void
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runtime·recover(byte *argp, Eface ret)
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{
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Stktop *top, *oldtop;
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Panic *p;
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// Must be a panic going on.
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if((p = g->panic) == nil || p->recovered)
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goto nomatch;
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// Frame must be at the top of the stack segment,
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// because each deferred call starts a new stack
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// segment as a side effect of using reflect.call.
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// (There has to be some way to remember the
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// variable argument frame size, and the segment
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// code already takes care of that for us, so we
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// reuse it.)
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//
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// As usual closures complicate things: the fp that
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// the closure implementation function claims to have
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// is where the explicit arguments start, after the
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// implicit pointer arguments and PC slot.
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// If we're on the first new segment for a closure,
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// then fp == top - top->args is correct, but if
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// the closure has its own big argument frame and
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// allocated a second segment (see below),
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// the fp is slightly above top - top->args.
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// That condition can't happen normally though
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// (stack pointers go down, not up), so we can accept
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// any fp between top and top - top->args as
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// indicating the top of the segment.
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top = (Stktop*)g->stackbase;
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if(argp < (byte*)top - top->argsize || (byte*)top < argp)
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goto nomatch;
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// The deferred call makes a new segment big enough
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// for the argument frame but not necessarily big
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// enough for the function's local frame (size unknown
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// at the time of the call), so the function might have
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// made its own segment immediately. If that's the
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// case, back top up to the older one, the one that
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// reflect.call would have made for the panic.
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//
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// The fp comparison here checks that the argument
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// frame that was copied during the split (the top->args
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// bytes above top->fp) abuts the old top of stack.
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// This is a correct test for both closure and non-closure code.
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oldtop = (Stktop*)top->stackbase;
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if(oldtop != nil && top->argp == (byte*)oldtop - top->argsize)
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top = oldtop;
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// Now we have the segment that was created to
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// run this call. It must have been marked as a panic segment.
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if(!top->panic)
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goto nomatch;
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// Okay, this is the top frame of a deferred call
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// in response to a panic. It can see the panic argument.
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p->recovered = 1;
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ret = p->arg;
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FLUSH(&ret);
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return;
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nomatch:
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ret.type = nil;
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ret.data = nil;
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FLUSH(&ret);
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}
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void
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runtime·startpanic(void)
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{
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if(runtime·mheap.cachealloc.size == 0) { // very early
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runtime·printf("runtime: panic before malloc heap initialized\n");
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m->mallocing = 1; // tell rest of panic not to try to malloc
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} else if(m->mcache == nil) // can happen if called from signal handler or throw
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m->mcache = runtime·allocmcache();
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if(m->dying) {
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runtime·printf("panic during panic\n");
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runtime·exit(3);
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}
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m->dying = 1;
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if(g != nil)
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g->writebuf = nil;
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runtime·xadd(&runtime·panicking, 1);
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runtime·lock(&paniclk);
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if(runtime·debug.schedtrace > 0 || runtime·debug.scheddetail > 0)
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runtime·schedtrace(true);
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runtime·freezetheworld();
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}
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void
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runtime·dopanic(int32 unused)
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{
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static bool didothers;
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bool crash;
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int32 t;
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if(g->sig != 0)
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runtime·printf("[signal %x code=%p addr=%p pc=%p]\n",
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g->sig, g->sigcode0, g->sigcode1, g->sigpc);
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if((t = runtime·gotraceback(&crash)) > 0){
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if(g != m->g0) {
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runtime·printf("\n");
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runtime·goroutineheader(g);
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runtime·traceback((uintptr)runtime·getcallerpc(&unused), (uintptr)runtime·getcallersp(&unused), 0, g);
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} else if(t >= 2) {
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runtime·printf("\nruntime stack:\n");
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runtime·traceback((uintptr)runtime·getcallerpc(&unused), (uintptr)runtime·getcallersp(&unused), 0, g);
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}
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if(!didothers) {
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didothers = true;
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runtime·tracebackothers(g);
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}
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}
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runtime·unlock(&paniclk);
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if(runtime·xadd(&runtime·panicking, -1) != 0) {
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// Some other m is panicking too.
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// Let it print what it needs to print.
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// Wait forever without chewing up cpu.
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// It will exit when it's done.
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static Lock deadlock;
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runtime·lock(&deadlock);
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runtime·lock(&deadlock);
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}
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if(crash)
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runtime·crash();
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runtime·exit(2);
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}
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void
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runtime·panicindex(void)
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{
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runtime·panicstring("index out of range");
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}
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void
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runtime·panicslice(void)
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{
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runtime·panicstring("slice bounds out of range");
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}
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void
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runtime·throwreturn(void)
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{
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// can only happen if compiler is broken
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runtime·throw("no return at end of a typed function - compiler is broken");
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}
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void
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runtime·throwinit(void)
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{
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// can only happen with linker skew
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runtime·throw("recursive call during initialization - linker skew");
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}
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void
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runtime·throw(int8 *s)
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{
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if(m->throwing == 0)
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m->throwing = 1;
|
|
runtime·startpanic();
|
|
runtime·printf("fatal error: %s\n", s);
|
|
runtime·dopanic(0);
|
|
*(int32*)0 = 0; // not reached
|
|
runtime·exit(1); // even more not reached
|
|
}
|
|
|
|
void
|
|
runtime·panicstring(int8 *s)
|
|
{
|
|
Eface err;
|
|
|
|
if(m->gcing) {
|
|
runtime·printf("panic: %s\n", s);
|
|
runtime·throw("panic during gc");
|
|
}
|
|
runtime·newErrorString(runtime·gostringnocopy((byte*)s), &err);
|
|
runtime·panic(err);
|
|
}
|
|
|
|
void
|
|
runtime·Goexit(void)
|
|
{
|
|
rundefer();
|
|
runtime·goexit();
|
|
}
|