libgo/go/runtime/traceback_gccgo.go - gofrontend - Git at Google

 // Copyright 2016 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.

 // Traceback support for gccgo.
 // The actual traceback code is written in C.

 package runtime

 import (
 	"runtime/internal/sys"
 	_ "unsafe" // for go:linkname
 )

 // For gccgo, use go:linkname to rename compiler-called functions to
 // themselves, so that the compiler will export them.
 // These are temporary for C runtime code to call.
 //go:linkname traceback runtime.traceback
 //go:linkname printtrace runtime.printtrace
 //go:linkname goroutineheader runtime.goroutineheader
 //go:linkname printcreatedby runtime.printcreatedby

 func printcreatedby(gp *g) {
 	// Show what created goroutine, except main goroutine (goid 1).
 	pc := gp.gopc
 	tracepc := pc // back up to CALL instruction for funcfileline.
 	entry := funcentry(tracepc)
 	if entry != 0 && tracepc > entry {
 		tracepc -= sys.PCQuantum
 	}
 	function, file, line := funcfileline(tracepc, -1)
 	if function != "" && showframe(function, gp) && gp.goid != 1 {
 		print("created by ", function, "\n")
 		print("\t", file, ":", line)
 		if entry != 0 && pc > entry {
 			print(" +", hex(pc-entry))
 		}
 		print("\n")
 	}
 }

 // tracebackg is used to collect stack traces from other goroutines.
 type tracebackg struct {
 	gp     *g
 	locbuf [_TracebackMaxFrames]location
 	c      int
 }

 // location is a location in the program, used for backtraces.
 type location struct {
 	pc       uintptr
 	filename string
 	function string
 	lineno   int
 }

 //extern runtime_callers
 func c_callers(skip int32, locbuf *location, max int32, keepThunks bool) int32

 // callers returns a stack trace of the current goroutine.
 // The gc version of callers takes []uintptr, but we take []location.
 func callers(skip int, locbuf []location) int {
 	n := c_callers(int32(skip), &locbuf[0], int32(len(locbuf)), false)
 	return int(n)
 }

 // traceback prints a traceback of the current goroutine.
 // This differs from the gc version, which is given pc, sp, lr and g and
 // can print a traceback of any goroutine.
 func traceback(skip int32) {
 	var locbuf [100]location
 	c := c_callers(skip+1, &locbuf[0], int32(len(locbuf)), false)
 	printtrace(locbuf[:c], getg())
 }

 // printtrace prints a traceback from locbuf.
 func printtrace(locbuf []location, gp *g) {
 	for i := range locbuf {
 		if showframe(locbuf[i].function, gp) {
 			print(locbuf[i].function, "\n\t", locbuf[i].filename, ":", locbuf[i].lineno, "\n")
 		}
 	}
 }

 // showframe returns whether to print a frame in a traceback.
 // name is the function name.
 func showframe(name string, gp *g) bool {
 	g := getg()
 	if g.m.throwing > 0 && gp != nil && (gp == g.m.curg || gp == g.m.caughtsig.ptr()) {
 		return true
 	}

 	// Gccgo can trace back through C functions called via cgo.
 	// We want to print those in the traceback.
 	// But unless GOTRACEBACK > 1 (checked below), still skip
 	// internal C functions and cgo-generated functions.
 	if name != "" && !contains(name, ".") && !hasprefix(name, "__go_") && !hasprefix(name, "_cgo_") {
 		return true
 	}

 	level, _, _ := gotraceback()

 	// Special case: always show runtime.gopanic frame, so that we can
 	// see where a panic started in the middle of a stack trace.
 	// See golang.org/issue/5832.
 	// __go_panic is the current gccgo name.
 	if name == "runtime.gopanic" || name == "__go_panic" {
 		return true
 	}

 	return level > 1 || contains(name, ".") && (!hasprefix(name, "runtime.") || isExportedRuntime(name))
 }

 // isExportedRuntime reports whether name is an exported runtime function.
 // It is only for runtime functions, so ASCII A-Z is fine.
 func isExportedRuntime(name string) bool {
 	const n = len("runtime.")
 	return len(name) > n && name[:n] == "runtime." && 'A' <= name[n] && name[n] <= 'Z'
 }

 var gStatusStrings = [...]string{
 	_Gidle:      "idle",
 	_Grunnable:  "runnable",
 	_Grunning:   "running",
 	_Gsyscall:   "syscall",
 	_Gwaiting:   "waiting",
 	_Gdead:      "dead",
 	_Gcopystack: "copystack",
 }

 func goroutineheader(gp *g) {
 	gpstatus := readgstatus(gp)

 	isScan := gpstatus&_Gscan != 0
 	gpstatus &^= _Gscan // drop the scan bit

 	// Basic string status
 	var status string
 	if 0 <= gpstatus && gpstatus < uint32(len(gStatusStrings)) {
 		status = gStatusStrings[gpstatus]
 	} else {
 		status = "???"
 	}

 	// Override.
 	if gpstatus == _Gwaiting && gp.waitreason != "" {
 		status = gp.waitreason
 	}

 	// approx time the G is blocked, in minutes
 	var waitfor int64
 	if (gpstatus == _Gwaiting || gpstatus == _Gsyscall) && gp.waitsince != 0 {
 		waitfor = (nanotime() - gp.waitsince) / 60e9
 	}
 	print("goroutine ", gp.goid, " [", status)
 	if isScan {
 		print(" (scan)")
 	}
 	if waitfor >= 1 {
 		print(", ", waitfor, " minutes")
 	}
 	if gp.lockedm != nil {
 		print(", locked to thread")
 	}
 	print("]:\n")
 }

 // isSystemGoroutine reports whether the goroutine g must be omitted in
 // stack dumps and deadlock detector.
 func isSystemGoroutine(gp *g) bool {
 	return gp.isSystemGoroutine
 }

 func tracebackothers(me *g) {
 	var tb tracebackg
 	tb.gp = me

 	// The getTraceback function will modify me's stack context.
 	// Preserve it in case we have been called via systemstack.
 	context := me.context
 	stackcontext := me.stackcontext

 	level, _, _ := gotraceback()

 	// Show the current goroutine first, if we haven't already.
 	g := getg()
 	gp := g.m.curg
 	if gp != nil && gp != me {
 		print("\n")
 		goroutineheader(gp)
 		gp.traceback = &tb
 		getTraceback(me, gp)
 		printtrace(tb.locbuf[:tb.c], nil)
 		printcreatedby(gp)
 	}

 	lock(&allglock)
 	for _, gp := range allgs {
 		if gp == me || gp == g.m.curg || readgstatus(gp) == _Gdead || isSystemGoroutine(gp) && level < 2 {
 			continue
 		}
 		print("\n")
 		goroutineheader(gp)

 		// gccgo's only mechanism for doing a stack trace is
 		// _Unwind_Backtrace.  And that only works for the
 		// current thread, not for other random goroutines.
 		// So we need to switch context to the goroutine, get
 		// the backtrace, and then switch back.
 		//
 		// This means that if g is running or in a syscall, we
 		// can't reliably print a stack trace.  FIXME.

 		// Note: gp.m == g.m occurs when tracebackothers is
 		// called from a signal handler initiated during a
 		// systemstack call. The original G is still in the
 		// running state, and we want to print its stack.
 		if gp.m != g.m && readgstatus(gp)&^_Gscan == _Grunning {
 			print("\tgoroutine running on other thread; stack unavailable\n")
 			printcreatedby(gp)
 		} else if readgstatus(gp)&^_Gscan == _Gsyscall {
 			print("\tgoroutine in C code; stack unavailable\n")
 			printcreatedby(gp)
 		} else {
 			gp.traceback = &tb
 			getTraceback(me, gp)
 			printtrace(tb.locbuf[:tb.c], nil)
 			printcreatedby(gp)
 		}
 	}
 	unlock(&allglock)

 	me.context = context
 	me.stackcontext = stackcontext
 }
	// Copyright 2016 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.

	// Traceback support for gccgo.
	// The actual traceback code is written in C.

	package runtime

	import (
	"runtime/internal/sys"
	_ "unsafe" // for go:linkname
	)

	// For gccgo, use go:linkname to rename compiler-called functions to
	// themselves, so that the compiler will export them.
	// These are temporary for C runtime code to call.
	//go:linkname traceback runtime.traceback
	//go:linkname printtrace runtime.printtrace
	//go:linkname goroutineheader runtime.goroutineheader
	//go:linkname printcreatedby runtime.printcreatedby

	func printcreatedby(gp *g) {
	// Show what created goroutine, except main goroutine (goid 1).
	pc := gp.gopc
	tracepc := pc // back up to CALL instruction for funcfileline.
	entry := funcentry(tracepc)
	if entry != 0 && tracepc > entry {
	tracepc -= sys.PCQuantum
	}
	function, file, line := funcfileline(tracepc, -1)
	if function != "" && showframe(function, gp) && gp.goid != 1 {
	print("created by ", function, "\n")
	print("\t", file, ":", line)
	if entry != 0 && pc > entry {
	print(" +", hex(pc-entry))
	}
	print("\n")
	}
	}

	// tracebackg is used to collect stack traces from other goroutines.
	type tracebackg struct {
	gp *g
	locbuf [_TracebackMaxFrames]location
	c int
	}

	// location is a location in the program, used for backtraces.
	type location struct {
	pc uintptr
	filename string
	function string
	lineno int
	}

	//extern runtime_callers
	func c_callers(skip int32, locbuf *location, max int32, keepThunks bool) int32

	// callers returns a stack trace of the current goroutine.
	// The gc version of callers takes []uintptr, but we take []location.
	func callers(skip int, locbuf []location) int {
	n := c_callers(int32(skip), &locbuf[0], int32(len(locbuf)), false)
	return int(n)
	}

	// traceback prints a traceback of the current goroutine.
	// This differs from the gc version, which is given pc, sp, lr and g and
	// can print a traceback of any goroutine.
	func traceback(skip int32) {
	var locbuf [100]location
	c := c_callers(skip+1, &locbuf[0], int32(len(locbuf)), false)
	printtrace(locbuf[:c], getg())
	}

	// printtrace prints a traceback from locbuf.
	func printtrace(locbuf []location, gp *g) {
	for i := range locbuf {
	if showframe(locbuf[i].function, gp) {
	print(locbuf[i].function, "\n\t", locbuf[i].filename, ":", locbuf[i].lineno, "\n")
	}
	}
	}

	// showframe returns whether to print a frame in a traceback.
	// name is the function name.
	func showframe(name string, gp *g) bool {
	g := getg()
	if g.m.throwing > 0 && gp != nil && (gp == g.m.curg \|\| gp == g.m.caughtsig.ptr()) {
	return true
	}

	// Gccgo can trace back through C functions called via cgo.
	// We want to print those in the traceback.
	// But unless GOTRACEBACK > 1 (checked below), still skip
	// internal C functions and cgo-generated functions.
	if name != "" && !contains(name, ".") && !hasprefix(name, "__go_") && !hasprefix(name, "_cgo_") {
	return true
	}

	level, _, _ := gotraceback()

	// Special case: always show runtime.gopanic frame, so that we can
	// see where a panic started in the middle of a stack trace.
	// See golang.org/issue/5832.
	// __go_panic is the current gccgo name.
	if name == "runtime.gopanic" \|\| name == "__go_panic" {
	return true
	}

	return level > 1 \|\| contains(name, ".") && (!hasprefix(name, "runtime.") \|\| isExportedRuntime(name))
	}

	// isExportedRuntime reports whether name is an exported runtime function.
	// It is only for runtime functions, so ASCII A-Z is fine.
	func isExportedRuntime(name string) bool {
	const n = len("runtime.")
	return len(name) > n && name[:n] == "runtime." && 'A' <= name[n] && name[n] <= 'Z'
	}

	var gStatusStrings = [...]string{
	_Gidle: "idle",
	_Grunnable: "runnable",
	_Grunning: "running",
	_Gsyscall: "syscall",
	_Gwaiting: "waiting",
	_Gdead: "dead",
	_Gcopystack: "copystack",
	}

	func goroutineheader(gp *g) {
	gpstatus := readgstatus(gp)

	isScan := gpstatus&_Gscan != 0
	gpstatus &^= _Gscan // drop the scan bit

	// Basic string status
	var status string
	if 0 <= gpstatus && gpstatus < uint32(len(gStatusStrings)) {
	status = gStatusStrings[gpstatus]
	} else {
	status = "???"
	}

	// Override.
	if gpstatus == _Gwaiting && gp.waitreason != "" {
	status = gp.waitreason
	}

	// approx time the G is blocked, in minutes
	var waitfor int64
	if (gpstatus == _Gwaiting \|\| gpstatus == _Gsyscall) && gp.waitsince != 0 {
	waitfor = (nanotime() - gp.waitsince) / 60e9
	}
	print("goroutine ", gp.goid, " [", status)
	if isScan {
	print(" (scan)")
	}
	if waitfor >= 1 {
	print(", ", waitfor, " minutes")
	}
	if gp.lockedm != nil {
	print(", locked to thread")
	}
	print("]:\n")
	}

	// isSystemGoroutine reports whether the goroutine g must be omitted in
	// stack dumps and deadlock detector.
	func isSystemGoroutine(gp *g) bool {
	return gp.isSystemGoroutine
	}

	func tracebackothers(me *g) {
	var tb tracebackg
	tb.gp = me

	// The getTraceback function will modify me's stack context.
	// Preserve it in case we have been called via systemstack.
	context := me.context
	stackcontext := me.stackcontext

	level, _, _ := gotraceback()

	// Show the current goroutine first, if we haven't already.
	g := getg()
	gp := g.m.curg
	if gp != nil && gp != me {
	print("\n")
	goroutineheader(gp)
	gp.traceback = &tb
	getTraceback(me, gp)
	printtrace(tb.locbuf[:tb.c], nil)
	printcreatedby(gp)
	}

	lock(&allglock)
	for _, gp := range allgs {
	if gp == me \|\| gp == g.m.curg \|\| readgstatus(gp) == _Gdead \|\| isSystemGoroutine(gp) && level < 2 {
	continue
	}
	print("\n")
	goroutineheader(gp)

	// gccgo's only mechanism for doing a stack trace is
	// _Unwind_Backtrace. And that only works for the
	// current thread, not for other random goroutines.
	// So we need to switch context to the goroutine, get
	// the backtrace, and then switch back.
	//
	// This means that if g is running or in a syscall, we
	// can't reliably print a stack trace. FIXME.

	// Note: gp.m == g.m occurs when tracebackothers is
	// called from a signal handler initiated during a
	// systemstack call. The original G is still in the
	// running state, and we want to print its stack.
	if gp.m != g.m && readgstatus(gp)&^_Gscan == _Grunning {
	print("\tgoroutine running on other thread; stack unavailable\n")
	printcreatedby(gp)
	} else if readgstatus(gp)&^_Gscan == _Gsyscall {
	print("\tgoroutine in C code; stack unavailable\n")
	printcreatedby(gp)
	} else {
	gp.traceback = &tb
	getTraceback(me, gp)
	printtrace(tb.locbuf[:tb.c], nil)
	printcreatedby(gp)
	}
	}
	unlock(&allglock)

	me.context = context
	me.stackcontext = stackcontext
	}