libgo/go/runtime/traceback_gccgo.go - rust-lang/gcc - 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 (
 	"internal/bytealg"
 	"runtime/internal/sys"
 	"unsafe"
 )

 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, false)
 	if function != "" && showframe(function, gp, false) && gp.goid != 1 {
 		printcreatedby1(function, file, line, entry, pc)
 	}
 }

 func printcreatedby1(function, file string, line int, entry, pc uintptr) {
 	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
 }

 //go:noescape
 //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)+1, &locbuf[0], int32(len(locbuf)), false)
 	return int(n)
 }

 //go:noescape
 //extern runtime_callersRaw
 func c_callersRaw(pcs *uintptr, max int32) int32

 // callersRaw returns a raw (PCs only) stack trace of the current goroutine.
 func callersRaw(pcbuf []uintptr) int {
 	n := c_callersRaw(&pcbuf[0], int32(len(pcbuf)))
 	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)
 	gp := getg()
 	printtrace(locbuf[:c], gp)
 	printcreatedby(gp)

 	if gp.ancestors == nil {
 		return
 	}
 	for _, ancestor := range *gp.ancestors {
 		printAncestorTraceback(ancestor)
 	}
 }

 // printAncestorTraceback prints the traceback of the given ancestor.
 func printAncestorTraceback(ancestor ancestorInfo) {
 	print("[originating from goroutine ", ancestor.goid, "]:\n")
 	for fidx, pc := range ancestor.pcs {
 		function, file, line, _ := funcfileline(pc, -1, false)
 		if showfuncinfo(function, fidx == 0) {
 			printAncestorTracebackFuncInfo(function, file, line, pc)
 		}
 	}
 	if len(ancestor.pcs) == _TracebackMaxFrames {
 		print("...additional frames elided...\n")
 	}
 	// Show what created goroutine, except main goroutine (goid 1).
 	function, file, line, _ := funcfileline(ancestor.gopc, -1, false)
 	if function != "" && showfuncinfo(function, false) && ancestor.goid != 1 {
 		printcreatedby1(function, file, line, funcentry(ancestor.gopc), ancestor.gopc)
 	}
 }

 // printAncestorTraceback prints the given function info at a given pc
 // within an ancestor traceback. The precision of this info is reduced
 // due to only have access to the pcs at the time of the caller
 // goroutine being created.
 func printAncestorTracebackFuncInfo(name, file string, line int, pc uintptr) {
 	if name == "runtime.gopanic" {
 		name = "panic"
 	}
 	print(name, "(...)\n")
 	print("\t", file, ":", line)
 	entry := funcentry(pc)
 	if pc > entry {
 		print(" +", hex(pc-entry))
 	}
 	print("\n")
 }

 // printtrace prints a traceback from locbuf.
 func printtrace(locbuf []location, gp *g) {
 	nprint := 0
 	for i := range locbuf {
 		if showframe(locbuf[i].function, gp, nprint == 0) {
 			name := locbuf[i].function
 			if name == "runtime.gopanic" {
 				name = "panic"
 			}
 			print(name, "\n\t", locbuf[i].filename, ":", locbuf[i].lineno, "\n")
 			nprint++
 		}
 	}
 }

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

 func showfuncinfo(name string, firstFrame bool) bool {
 	// 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 != "" && bytealg.IndexByteString(name, '.') < 0 && !hasPrefix(name, "__go_") && !hasPrefix(name, "_cgo_") {
 		return true
 	}

 	level, _, _ := gotraceback()
 	if level > 1 {
 		// Show all frames.
 		return true
 	}

 	if name == "" {
 		return false
 	}

 	// Special case: always show runtime.gopanic frame
 	// in the middle of a stack trace, so that we can
 	// see the boundary between ordinary code and
 	// panic-induced deferred code.
 	// See golang.org/issue/5832.
 	if name == "runtime.gopanic" && !firstFrame {
 		return true
 	}

 	return bytealg.IndexByteString(name, '.') >= 0 && (!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. Here also check
 // for mangled functions from runtime/<...>, which will be prefixed with
 // "runtime_1".
 func isExportedRuntime(name string) bool {
 	const n = len("runtime.")
 	if hasPrefix(name, "runtime_1") {
 		return true
 	}
 	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",
 	_Gexitingsyscall: "exiting syscall",
 }

 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 != waitReasonZero {
 		status = gp.waitreason.String()
 	}

 	// 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 != 0 {
 		print(", locked to thread")
 	}
 	print("]:\n")
 }

 // isSystemGoroutine reports whether the goroutine g must be omitted
 // in stack dumps and deadlock detector. This is any goroutine that
 // starts at a runtime.* entry point, except for runtime.main and
 // sometimes runtime.runfinq.
 //
 // If fixed is true, any goroutine that can vary between user and
 // system (that is, the finalizer goroutine) is considered a user
 // goroutine.
 func isSystemGoroutine(gp *g, fixed bool) bool {
 	if !gp.isSystemGoroutine {
 		return false
 	}
 	if fixed && gp.isFinalizerGoroutine {
 		// This goroutine can vary. In fixed mode,
 		// always consider it a user goroutine.
 		return false
 	}
 	return true
 }

 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 = (uintptr)(noescape(unsafe.Pointer(&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, false) && 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 = (uintptr)(noescape(unsafe.Pointer(&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 (
	"internal/bytealg"
	"runtime/internal/sys"
	"unsafe"
	)

	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, false)
	if function != "" && showframe(function, gp, false) && gp.goid != 1 {
	printcreatedby1(function, file, line, entry, pc)
	}
	}

	func printcreatedby1(function, file string, line int, entry, pc uintptr) {
	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
	}

	//go:noescape
	//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)+1, &locbuf[0], int32(len(locbuf)), false)
	return int(n)
	}

	//go:noescape
	//extern runtime_callersRaw
	func c_callersRaw(pcs *uintptr, max int32) int32

	// callersRaw returns a raw (PCs only) stack trace of the current goroutine.
	func callersRaw(pcbuf []uintptr) int {
	n := c_callersRaw(&pcbuf[0], int32(len(pcbuf)))
	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)
	gp := getg()
	printtrace(locbuf[:c], gp)
	printcreatedby(gp)

	if gp.ancestors == nil {
	return
	}
	for _, ancestor := range *gp.ancestors {
	printAncestorTraceback(ancestor)
	}
	}

	// printAncestorTraceback prints the traceback of the given ancestor.
	func printAncestorTraceback(ancestor ancestorInfo) {
	print("[originating from goroutine ", ancestor.goid, "]:\n")
	for fidx, pc := range ancestor.pcs {
	function, file, line, _ := funcfileline(pc, -1, false)
	if showfuncinfo(function, fidx == 0) {
	printAncestorTracebackFuncInfo(function, file, line, pc)
	}
	}
	if len(ancestor.pcs) == _TracebackMaxFrames {
	print("...additional frames elided...\n")
	}
	// Show what created goroutine, except main goroutine (goid 1).
	function, file, line, _ := funcfileline(ancestor.gopc, -1, false)
	if function != "" && showfuncinfo(function, false) && ancestor.goid != 1 {
	printcreatedby1(function, file, line, funcentry(ancestor.gopc), ancestor.gopc)
	}
	}

	// printAncestorTraceback prints the given function info at a given pc
	// within an ancestor traceback. The precision of this info is reduced
	// due to only have access to the pcs at the time of the caller
	// goroutine being created.
	func printAncestorTracebackFuncInfo(name, file string, line int, pc uintptr) {
	if name == "runtime.gopanic" {
	name = "panic"
	}
	print(name, "(...)\n")
	print("\t", file, ":", line)
	entry := funcentry(pc)
	if pc > entry {
	print(" +", hex(pc-entry))
	}
	print("\n")
	}

	// printtrace prints a traceback from locbuf.
	func printtrace(locbuf []location, gp *g) {
	nprint := 0
	for i := range locbuf {
	if showframe(locbuf[i].function, gp, nprint == 0) {
	name := locbuf[i].function
	if name == "runtime.gopanic" {
	name = "panic"
	}
	print(name, "\n\t", locbuf[i].filename, ":", locbuf[i].lineno, "\n")
	nprint++
	}
	}
	}

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

	func showfuncinfo(name string, firstFrame bool) bool {
	// 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 != "" && bytealg.IndexByteString(name, '.') < 0 && !hasPrefix(name, "__go_") && !hasPrefix(name, "_cgo_") {
	return true
	}

	level, _, _ := gotraceback()
	if level > 1 {
	// Show all frames.
	return true
	}

	if name == "" {
	return false
	}

	// Special case: always show runtime.gopanic frame
	// in the middle of a stack trace, so that we can
	// see the boundary between ordinary code and
	// panic-induced deferred code.
	// See golang.org/issue/5832.
	if name == "runtime.gopanic" && !firstFrame {
	return true
	}

	return bytealg.IndexByteString(name, '.') >= 0 && (!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. Here also check
	// for mangled functions from runtime/<...>, which will be prefixed with
	// "runtime_1".
	func isExportedRuntime(name string) bool {
	const n = len("runtime.")
	if hasPrefix(name, "runtime_1") {
	return true
	}
	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",
	_Gexitingsyscall: "exiting syscall",
	}

	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 != waitReasonZero {
	status = gp.waitreason.String()
	}

	// 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 != 0 {
	print(", locked to thread")
	}
	print("]:\n")
	}

	// isSystemGoroutine reports whether the goroutine g must be omitted
	// in stack dumps and deadlock detector. This is any goroutine that
	// starts at a runtime.* entry point, except for runtime.main and
	// sometimes runtime.runfinq.
	//
	// If fixed is true, any goroutine that can vary between user and
	// system (that is, the finalizer goroutine) is considered a user
	// goroutine.
	func isSystemGoroutine(gp *g, fixed bool) bool {
	if !gp.isSystemGoroutine {
	return false
	}
	if fixed && gp.isFinalizerGoroutine {
	// This goroutine can vary. In fixed mode,
	// always consider it a user goroutine.
	return false
	}
	return true
	}

	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 = (uintptr)(noescape(unsafe.Pointer(&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, false) && 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 = (uintptr)(noescape(unsafe.Pointer(&tb)))
	getTraceback(me, gp)
	printtrace(tb.locbuf[:tb.c], nil)
	printcreatedby(gp)
	}
	}
	unlock(&allglock)

	me.context = context
	me.stackcontext = stackcontext
	}