runtime: record goroutine creation pc and display in traceback

package main

func main() {
        go func() { *(*int)(nil) = 0 }()
        select{}
}

panic: runtime error: invalid memory address or nil pointer dereference

[signal 0xb code=0x1 addr=0x0 pc=0x1c96]

runtime.panic+0xac /Users/rsc/g/go/src/pkg/runtime/proc.c:1083
        runtime.panic(0x11bf0, 0xf8400011f0)
runtime.panicstring+0xa3 /Users/rsc/g/go/src/pkg/runtime/runtime.c:116
        runtime.panicstring(0x29a57, 0x0)
runtime.sigpanic+0x144 /Users/rsc/g/go/src/pkg/runtime/darwin/thread.c:470
        runtime.sigpanic()
main._func_001+0x16 /Users/rsc/g/go/src/pkg/runtime/x.go:188
        main._func_001()
runtime.goexit /Users/rsc/g/go/src/pkg/runtime/proc.c:150
        runtime.goexit()
----- goroutine created by -----
main.main+0x3d /Users/rsc/g/go/src/pkg/runtime/x.go:4

goroutine 1 [4]:
runtime.gosched+0x77 /Users/rsc/g/go/src/pkg/runtime/proc.c:598
        runtime.gosched()
runtime.block+0x27 /Users/rsc/g/go/src/pkg/runtime/chan.c:680
        runtime.block()
main.main+0x44 /Users/rsc/g/go/src/pkg/runtime/x.go:5
        main.main()
runtime.mainstart+0xf /Users/rsc/g/go/src/pkg/runtime/amd64/asm.s:77
        runtime.mainstart()
runtime.goexit /Users/rsc/g/go/src/pkg/runtime/proc.c:150
        runtime.goexit()
----- goroutine created by -----
_rt0_amd64+0x8e /Users/rsc/g/go/src/pkg/runtime/amd64/asm.s:64

Fixes #1563.

R=r
CC=golang-dev
https://golang.org/cl/4243046

1 files changed, 11 insertions, 0 deletions

diff --git a/src/pkg/runtime/amd64/traceback.c b/src/pkg/runtime/amd64/traceback.c
index 035dc560c5..0f6733c364 100644
--- a/src/pkg/runtime/amd64/traceback.c
+++ b/src/pkg/runtime/amd64/traceback.c
@@ -182,6 +182,17 @@ gentraceback(byte *pc0, byte *sp, G *g, int32 skip, uintptr *pcbuf, int32 max)
 		sp = fp;
 		fp = nil;
 	}
+	
+	if(pcbuf == nil && (pc = g->gopc) != 0 && (f = runtime·findfunc(pc)) != nil) {
+		runtime·printf("----- goroutine created by -----\n%S", f->name);
+		if(pc > f->entry)
+			runtime·printf("+%p", (uintptr)(pc - f->entry));
+		tracepc = pc;	// back up to CALL instruction for funcline.
+		if(n > 0 && pc > f->entry)
+			tracepc--;
+		runtime·printf(" %S:%d\n", f->src, runtime·funcline(f, tracepc));
+	}
+		
 	return n;
 }