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// Copyright 2009 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.
#include "runtime.h"
#include "arch_GOARCH.h"
#include "malloc.h"
void runtime·deferproc(void);
void runtime·newproc(void);
void runtime·newstack(void);
void runtime·morestack(void);
void runtime·sigpanic(void);
void _div(void);
void _mod(void);
void _divu(void);
void _modu(void);
int32
runtime·gentraceback(byte *pc0, byte *sp, byte *lr0, G *gp, int32 skip, uintptr *pcbuf, int32 max)
{
int32 i, n, iter;
uintptr pc, lr, tracepc, x;
byte *fp;
bool waspanic;
Stktop *stk;
Func *f;
pc = (uintptr)pc0;
lr = (uintptr)lr0;
fp = nil;
waspanic = false;
// If the PC is goexit, the goroutine hasn't started yet.
if(pc == (uintptr)runtime·goexit && gp->fnstart != nil) {
pc = (uintptr)gp->fnstart->fn;
lr = (uintptr)runtime·goexit;
}
// If the PC is zero, it's likely a nil function call.
// Start in the caller's frame.
if(pc == 0) {
pc = lr;
lr = 0;
}
n = 0;
stk = (Stktop*)gp->stackbase;
for(iter = 0; iter < 100 && n < max; iter++) { // iter avoids looping forever
// Typically:
// pc is the PC of the running function.
// sp is the stack pointer at that program counter.
// fp is the frame pointer (caller's stack pointer) at that program counter, or nil if unknown.
// stk is the stack containing sp.
// The caller's program counter is lr, unless lr is zero, in which case it is *(uintptr*)sp.
if(pc == (uintptr)runtime·lessstack) {
// Hit top of stack segment. Unwind to next segment.
pc = (uintptr)stk->gobuf.pc;
sp = (byte*)stk->gobuf.sp;
lr = 0;
fp = nil;
if(pcbuf == nil && runtime·showframe(nil, gp == m->curg))
runtime·printf("----- stack segment boundary -----\n");
stk = (Stktop*)stk->stackbase;
continue;
}
if(pc <= 0x1000 || (f = runtime·findfunc(pc)) == nil)
break;
// Found an actual function.
if(lr == 0)
lr = *(uintptr*)sp;
if(fp == nil) {
fp = sp;
if(pc > f->entry && f->frame >= 0)
fp += f->frame;
}
if(skip > 0)
skip--;
else if(pcbuf != nil)
pcbuf[n++] = pc;
else {
if(runtime·showframe(f, gp == m->curg)) {
// Print during crash.
// main(0x1, 0x2, 0x3)
// /home/rsc/go/src/runtime/x.go:23 +0xf
tracepc = pc; // back up to CALL instruction for funcline.
if(n > 0 && pc > f->entry && !waspanic)
tracepc -= sizeof(uintptr);
if(m->throwing && gp == m->curg)
runtime·printf("[fp=%p] ", fp);
runtime·printf("%S(", f->name);
for(i = 0; i < f->args/sizeof(uintptr); i++) {
if(i != 0)
runtime·prints(", ");
runtime·printhex(((uintptr*)fp)[1+i]);
if(i >= 4) {
runtime·prints(", ...");
break;
}
}
runtime·prints(")\n");
runtime·printf("\t%S:%d", f->src, runtime·funcline(f, tracepc));
if(pc > f->entry)
runtime·printf(" +%p", (uintptr)(pc - f->entry));
runtime·printf("\n");
}
n++;
}
waspanic = f->entry == (uintptr)runtime·sigpanic;
if(pcbuf == nil && f->entry == (uintptr)runtime·newstack && gp == m->g0) {
runtime·printf("----- newstack called from goroutine %D -----\n", m->curg->goid);
pc = (uintptr)m->morepc;
sp = (byte*)m->moreargp - sizeof(void*);
lr = (uintptr)m->morebuf.pc;
fp = (byte*)m->morebuf.sp;
gp = m->curg;
stk = (Stktop*)gp->stackbase;
continue;
}
if(pcbuf == nil && f->entry == (uintptr)runtime·lessstack && gp == m->g0) {
runtime·printf("----- lessstack called from goroutine %D -----\n", m->curg->goid);
gp = m->curg;
stk = (Stktop*)gp->stackbase;
sp = (byte*)stk->gobuf.sp;
pc = (uintptr)stk->gobuf.pc;
fp = nil;
lr = 0;
continue;
}
// Unwind to next frame.
pc = lr;
lr = 0;
sp = fp;
fp = nil;
// If this was div or divu or mod or modu, the caller had
// an extra 8 bytes on its stack. Adjust sp.
if(f->entry == (uintptr)_div || f->entry == (uintptr)_divu || f->entry == (uintptr)_mod || f->entry == (uintptr)_modu)
sp += 8;
// If this was deferproc or newproc, the caller had an extra 12.
if(f->entry == (uintptr)runtime·deferproc || f->entry == (uintptr)runtime·newproc)
sp += 12;
// sighandler saves the lr on stack before faking a call to sigpanic
if(waspanic) {
x = *(uintptr *)sp;
sp += 4;
f = runtime·findfunc(pc);
if (f == nil) {
pc = x;
} else if (f->frame == 0)
lr = x;
}
}
if(pcbuf == nil && (pc = gp->gopc) != 0 && (f = runtime·findfunc(pc)) != nil
&& runtime·showframe(f, gp == m->curg) && gp->goid != 1) {
runtime·printf("created by %S\n", f->name);
tracepc = pc; // back up to CALL instruction for funcline.
if(n > 0 && pc > f->entry)
tracepc -= sizeof(uintptr);
runtime·printf("\t%S:%d", f->src, runtime·funcline(f, tracepc));
if(pc > f->entry)
runtime·printf(" +%p", (uintptr)(pc - f->entry));
runtime·printf("\n");
}
return n;
}
void
runtime·traceback(byte *pc0, byte *sp, byte *lr, G *gp)
{
if(gp->status == Gsyscall) {
// Override signal registers if blocked in system call.
pc0 = gp->sched.pc;
sp = (byte*)gp->sched.sp;
lr = nil;
}
runtime·gentraceback(pc0, sp, lr, gp, 0, nil, 100);
}
// func caller(n int) (pc uintptr, file string, line int, ok bool)
int32
runtime·callers(int32 skip, uintptr *pcbuf, int32 m)
{
byte *pc, *sp;
sp = runtime·getcallersp(&skip);
pc = runtime·getcallerpc(&skip);
return runtime·gentraceback(pc, sp, 0, g, skip, pcbuf, m);
}
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