runtime: convert a few traceback-related functions from proc.c to traceback.go

They were in proc.c mainly because there was no portable
traceback source file. As part of converting them to Go,
move to traceback.go.

In order to get access to the PC of _rt0_go,
rename to runtime.rt0_go.

LGTM=r
R=golang-codereviews, r
CC=dvyukov, golang-codereviews, iant, khr
https://golang.org/cl/139110043

1 files changed, 3 insertions, 125 deletions

diff --git a/src/pkg/runtime/proc.c b/src/pkg/runtime/proc.c
index 9229c53a8c..b85baca14d 100644
--- a/src/pkg/runtime/proc.c
+++ b/src/pkg/runtime/proc.c
@@ -185,8 +185,6 @@ runtime·schedinit(void)
 	if(p != nil && !runtime·strcmp(p, (byte*)"0"))
 		runtime·copystack = false;
 
-	mstats.enablegc = 1;
-
 	if(runtime·buildVersion.str == nil) {
 		// Condition should never trigger.  This code just serves
 		// to ensure runtime·buildVersion is kept in the resulting binary.
@@ -244,7 +242,10 @@ runtime·main(void)
 
 	if(g->m != &runtime·m0)
 		runtime·throw("runtime·main not on m0");
+
 	runtime·init();
+	mstats.enablegc = 1; // now that runtime is initialized, GC is okay
+
 	main·init();
 
 	if(g->defer != &d || d.fn != &initDone)
@@ -268,118 +269,12 @@ runtime·main(void)
 		*(int32*)runtime·main = 0;
 }
 
-void
-runtime·goroutineheader(G *gp)
-{
-	String status;
-	int64 waitfor;
-	uint32 gpstatus;
-
-	gpstatus = runtime·readgstatus(gp);
-	switch(gpstatus) {
-	case Gidle:
-		status = runtime·gostringnocopy((byte*)"idle");
-		break;
-	case Grunnable:
-		status = runtime·gostringnocopy((byte*)"runnable");
-		break;
-	case Grunning:
-		status = runtime·gostringnocopy((byte*)"running");
-		break;
-	case Gsyscall:
-		status = runtime·gostringnocopy((byte*)"syscall");
-		break;
-	case Gwaiting:
-		if(gp->waitreason.str != nil)
-			status = gp->waitreason;
-		else
-			status = runtime·gostringnocopy((byte*)"waiting");
-		break;
-	case Gscan:
-		status = runtime·gostringnocopy((byte*)"scan");
-		break;
-	case Gscanrunnable:
-		status =  runtime·gostringnocopy((byte*)"scanrunnable");
-		break;
-	case Gscanrunning:
-		status = runtime·gostringnocopy((byte*)"scanrunning");
-		break;
-	case Gscansyscall:
-		status = runtime·gostringnocopy((byte*)"scansyscall");
-		break;
-	case Gscanenqueue:
-		status = runtime·gostringnocopy((byte*)"scanenqueue");
-		break;
-	case Gscanwaiting:
-		if(gp->waitreason.str != nil)
-			status = gp->waitreason;
-		else
-			status = runtime·gostringnocopy((byte*)"scanwaiting");
-		break;
-	case Gcopystack:
-		status = runtime·gostringnocopy((byte*)"copystack");
-		break;
-	default:
-		status = runtime·gostringnocopy((byte*)"???");
-		break;
-	}
-
-	// approx time the G is blocked, in minutes
-	waitfor = 0;
-	gpstatus = gpstatus&~Gscan; // drop the scan bit
-	if((gpstatus == Gwaiting || gpstatus == Gsyscall) && gp->waitsince != 0)
-		waitfor = (runtime·nanotime() - gp->waitsince) / (60LL*1000*1000*1000);
-
-	runtime·printf("goroutine %D [%S", gp->goid, status);
-	if(waitfor >= 1)
-		runtime·printf(", %D minutes", waitfor);
-	if(gp->lockedm != nil)
-		runtime·printf(", locked to thread");
-	runtime·printf("]:\n");
-}
-
 static void
 dumpgstatus(G* gp)
 {
 	runtime·printf("runtime: gp=%p, goid=%D, gp->atomicstatus=%d\n", gp, gp->goid, runtime·readgstatus(gp));
 }
 
-void
-runtime·tracebackothers(G *me)
-{
-	G *gp;
-	int32 traceback;
-	uintptr i;
-	uint32 status;
-
-	traceback = runtime·gotraceback(nil);
-	
-	// Show the current goroutine first, if we haven't already.
-	if((gp = g->m->curg) != nil && gp != me) {
-		runtime·printf("\n");
-		runtime·goroutineheader(gp);
-		runtime·traceback(~(uintptr)0, ~(uintptr)0, 0, gp);
-	}
-
-	runtime·lock(&allglock);
-	for(i = 0; i < runtime·allglen; i++) {
-		gp = runtime·allg[i];
-		if(gp == me || gp == g->m->curg || runtime·readgstatus(gp) == Gdead)
-			continue;
-		if(gp->issystem && traceback < 2)
-			continue;
-		runtime·printf("\n");
-		runtime·goroutineheader(gp);
-		status = runtime·readgstatus(gp);
-		if((status&~Gscan) == Grunning){
-			runtime·printf("\tgoroutine running on other thread; stack unavailable\n");
-			runtime·printcreatedby(gp);
-		} else
-			runtime·traceback(~(uintptr)0, ~(uintptr)0, 0, gp);
-	}
-	runtime·unlock(&allglock);
-}
-
 static void
 checkmcount(void)
 {
@@ -3373,23 +3268,6 @@ runtime·testSchedLocalQueueSteal(void)
 	}
 }
 
-extern void runtime·morestack(void);
-uintptr runtime·externalthreadhandlerp;
-
-// Does f mark the top of a goroutine stack?
-bool
-runtime·topofstack(Func *f)
-{
-	return f->entry == (uintptr)runtime·goexit ||
-		f->entry == (uintptr)runtime·mstart ||
-		f->entry == (uintptr)runtime·mcall ||
-		f->entry == (uintptr)runtime·onM ||
-		f->entry == (uintptr)runtime·morestack ||
-		f->entry == (uintptr)runtime·lessstack ||
-		f->entry == (uintptr)_rt0_go ||
-		(runtime·externalthreadhandlerp != 0 && f->entry == runtime·externalthreadhandlerp);
-}
-
 void
 runtime·setmaxthreads_m(void)
 {