1 files changed, 228 insertions, 0 deletions
diff --git a/libgo/go/runtime/traceback_gccgo.go b/libgo/go/runtime/traceback_gccgo.go
new file mode 100644
index 0000000000..611aba91a4
--- /dev/null
+++ b/libgo/go/runtime/traceback_gccgo.go
@@ -0,0 +1,228 @@
+// 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 !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 {
+	// FIXME.
+	return false
+}
+
+func tracebackothers(me *g) {
+	var tb tracebackg
+	tb.gp = me
+
+	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)
+}