languages/go
languages/go
1
0
Fork 0
mirror of https://github.com/golang/go synced 2024-10-14 03:43:28 +00:00
Code Issues Packages Projects Releases Wiki Activity

runtime: convert traceback*.c to Go

Browse source 
The two converted files were nearly identical.
Instead of continuing that duplication, I merged them
into a single traceback.go.

Tested on arm, amd64, amd64p32, and 386.

LGTM=r
R=golang-codereviews, remyoudompheng, dave, r
CC=dvyukov, golang-codereviews, iant, khr
https://golang.org/cl/134200044
This commit is contained in:
Russ Cox 2014-09-02 15:12:53 -04:00
parent 8e89f87158
commit fa2af441f1
14 changed files with 668 additions and 838 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

31
src/cmd/api/goapi.go
View file

@ -379,13 +379,30 @@ func (w *Walker) parseFile(dir, file string) (*ast.File, error) {
if w.context != nil && file == fmt.Sprintf("zruntime_defs_%s_%s.go", w.context.GOOS, w.context.GOARCH) {
// Just enough to keep the api checker happy.
src := "package runtime; type (" +
" maptype struct{}; _type struct{}; alg struct{};" +
" mspan struct{}; m struct{}; mutex struct{}; slicetype struct{};" +
" iface struct{}; eface struct{}; interfacetype struct{}; itab struct{};" +
" mcache struct{}; sudog struct{}; g struct{};" +
" hchan struct{}; chantype struct{}; waitq struct{};" +
" note struct{}; wincallbackcontext struct{};" +
" gobuf struct{}; funcval struct{}; _func struct{};" +
" _func struct{};" +
" _type struct{};" +
" alg struct{};" +
" chantype struct{};" +
" context struct{};" + // windows
" eface struct{};" +
" funcval struct{};" +
" g struct{};" +
" gobuf struct{};" +
" hchan struct{};" +
" iface struct{};" +
" interfacetype struct{};" +
" itab struct{};" +
" m struct{};" +
" maptype struct{};" +
" mcache struct{};" +
" mspan struct{};" +
" mutex struct{};" +
" note struct{};" +
" slicetype struct{};" +
" stkframe struct{};" +
" sudog struct{};" +
" waitq struct{};" +
" wincallbackcontext struct{};" +
"); " +
"const ( cb_max = 2000 )"
f, err = parser.ParseFile(fset, filename, src, 0)

24
src/pkg/runtime/extern.go
View file

@ -86,11 +86,9 @@ import "unsafe"
// If all other goroutines exit, the program crashes.
func Goexit()
// We assume that all architectures turn faults and the like
// into apparent calls to runtime.sigpanic. If we see a "call"
// to runtime.sigpanic, we do not back up the PC to find the
// line number of the CALL instruction, because there is no CALL.
var sigpanic byte
// sigpanic is the C function sigpanic.
// That is, unsafe.Pointer(&sigpanic) is the C function pointer for sigpanic.
var sigpanic struct{}
// Caller reports file and line number information about function invocations on
// the calling goroutine's stack. The argument skip is the number of stack frames
@ -103,7 +101,7 @@ func Caller(skip int) (pc uintptr, file string, line int, ok bool) {
// and what it called, so that we can see if it
// "called" sigpanic.
var rpc [2]uintptr
if callers(int32(1+skip-1), &rpc[0], 2) < 2 {
if callers(1+skip-1, &rpc[0], 2) < 2 {
return
}
f := findfunc(rpc[1])
@ -117,6 +115,9 @@ func Caller(skip int) (pc uintptr, file string, line int, ok bool) {
pc = rpc[1]
xpc := pc
g := findfunc(rpc[0])
// All architectures turn faults into apparent calls to sigpanic.
// If we see a call to sigpanic, we do not back up the PC to find
// the line number of the call instruction, because there is no call.
if xpc > f.entry && (g == nil || g.entry != uintptr(unsafe.Pointer(&sigpanic))) {
xpc--
}
@ -142,18 +143,9 @@ func Callers(skip int, pc []uintptr) int {
if len(pc) == 0 {
return 0
}
return int(callers(int32(skip), &pc[0], int32(len(pc))))
return callers(skip, &pc[0], len(pc))
}
//go:noescape
func callers(int32, *uintptr, int32) int32
//go:noescape
func gcallers(*g, int32, *uintptr, int32) int32
//go:noescape
func gentraceback(uintptr, uintptr, uintptr, *g, int32, *uintptr, int32, unsafe.Pointer, unsafe.Pointer, bool) int32
func getgoroot() string
// GOROOT returns the root of the Go tree.

4
src/pkg/runtime/heapdump.c
View file

@ -380,6 +380,7 @@ dumpgoroutine(G *gp)
ChildInfo child;
Defer *d;
Panic *p;
bool (*fn)(Stkframe*, void*);
if(gp->syscallstack != (uintptr)nil) {
sp = gp->syscallsp;
@ -413,7 +414,8 @@ dumpgoroutine(G *gp)
child.depth = 0;
if(!ScanStackByFrames)
runtime·throw("need frame info to dump stacks");
runtime·gentraceback(pc, sp, lr, gp, 0, nil, 0x7fffffff, dumpframe, &child, false);
fn = dumpframe;
runtime·gentraceback(pc, sp, lr, gp, 0, nil, 0x7fffffff, &fn, &child, false);
// dump defer & panic records
for(d = gp->defer; d != nil; d = d->link) {

8
src/pkg/runtime/mgc0.c
View file

@ -685,6 +685,7 @@ scanstack(G *gp)
int32 n;
Stktop *stk;
uintptr sp, guard;
bool (*fn)(Stkframe*, void*);
switch(runtime·readgstatus(gp)) {
default:
@ -726,7 +727,8 @@ scanstack(G *gp)
USED(sp);
USED(stk);
USED(guard);
runtime·gentraceback(~(uintptr)0, ~(uintptr)0, 0, gp, 0, nil, 0x7fffffff, scanframe, nil, false);
fn = scanframe;
runtime·gentraceback(~(uintptr)0, ~(uintptr)0, 0, gp, 0, nil, 0x7fffffff, &fn, nil, false);
} else {
n = 0;
while(stk) {
@ -1779,6 +1781,7 @@ runtime·getgcmask(byte *p, Type *t, byte **mask, uintptr *len)
Stkframe frame;
uintptr i, n, off;
byte *base, bits, shift, *b;
bool (*cb)(Stkframe*, void*);
*mask = nil;
*len = 0;
@ -1823,7 +1826,8 @@ runtime·getgcmask(byte *p, Type *t, byte **mask, uintptr *len)
// stack
frame.fn = nil;
frame.sp = (uintptr)p;
runtime·gentraceback((uintptr)runtime·getcallerpc(&p), (uintptr)runtime·getcallersp(&p), 0, g, 0, nil, 1000, getgcmaskcb, &frame, false);
cb = getgcmaskcb;
runtime·gentraceback((uintptr)runtime·getcallerpc(&p), (uintptr)runtime·getcallersp(&p), 0, g, 0, nil, 1000, &cb, &frame, false);
if(frame.fn != nil) {
Func *f;
StackMap *stackmap;

10
src/pkg/runtime/mprof.go
View file

@ -234,7 +234,7 @@ func mProf_GC() {
// Called by malloc to record a profiled block.
func mProf_Malloc(p unsafe.Pointer, size uintptr) {
var stk [maxStack]uintptr
nstk := callers(1, &stk[0], int32(len(stk)))
nstk := callers(1, &stk[0], len(stk))
lock(&proflock)
b := stkbucket(memProfile, size, stk[:nstk], true)
mp := b.mp()
@ -304,9 +304,9 @@ func blockevent(cycles int64, skip int) {
var nstk int
var stk [maxStack]uintptr
if gp.m.curg == nil || gp.m.curg == gp {
nstk = int(callers(int32(skip), &stk[0], int32(len(stk))))
nstk = callers(skip, &stk[0], len(stk))
} else {
nstk = int(gcallers(gp.m.curg, int32(skip), &stk[0], int32(len(stk))))
nstk = gcallers(gp.m.curg, skip, &stk[0], len(stk))
}
lock(&proflock)
b := stkbucket(blockProfile, 0, stk[:nstk], true)
@ -557,8 +557,8 @@ func GoroutineProfile(p []StackRecord) (n int, ok bool) {
}
func saveg(pc, sp uintptr, gp *g, r *StackRecord) {
n := gentraceback(pc, sp, 0, gp, 0, &r.Stack0[0], int32(len(r.Stack0)), nil, nil, false)
if int(n) < len(r.Stack0) {
n := gentraceback(pc, sp, 0, gp, 0, &r.Stack0[0], len(r.Stack0), nil, nil, false)
if n < len(r.Stack0) {
r.Stack0[n] = 0
}
}

11
src/pkg/runtime/os_windows_386.go Normal file
View file

@ -0,0 +1,11 @@
// Copyright 2014 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.
package runtime
// contextPC returns the EIP (program counter) register from the context.
func contextPC(r *context) uintptr { return uintptr(r.eip) }
// contextSP returns the ESP (stack pointer) register from the context.
func contextSP(r *context) uintptr { return uintptr(r.esp) }

11
src/pkg/runtime/os_windows_amd64.go Normal file
View file

@ -0,0 +1,11 @@
// Copyright 2014 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.
package runtime
// contextPC returns the RIP (program counter) register from the context.
func contextPC(r *context) uintptr { return uintptr(r.rip) }
// contextSP returns the RSP (stack pointer) register from the context.
func contextSP(r *context) uintptr { return uintptr(r.rsp) }

8
src/pkg/runtime/runtime.h
View file

@ -666,7 +666,7 @@ struct Stkframe
uintptr arglen; // number of bytes at argp
};
int32 runtime·gentraceback(uintptr, uintptr, uintptr, G*, int32, uintptr*, int32, bool(*)(Stkframe*, void*), void*, bool);
intgo runtime·gentraceback(uintptr, uintptr, uintptr, G*, intgo, uintptr*, intgo, bool(**)(Stkframe*, void*), void*, bool);
void runtime·traceback(uintptr pc, uintptr sp, uintptr lr, G* gp);
void runtime·tracebackothers(G*);
bool runtime·haszeroargs(uintptr pc);
@ -854,8 +854,8 @@ void runtime·exitsyscall(void);
void runtime·entersyscallblock_m(void);
G* runtime·newproc1(FuncVal*, byte*, int32, int32, void*);
bool runtime·sigsend(int32 sig);
int32 runtime·callers(int32, uintptr*, int32);
int32 runtime·gcallers(G*, int32, uintptr*, int32);
intgo runtime·callers(intgo, uintptr*, intgo);
intgo runtime·gcallers(G*, intgo, uintptr*, intgo);
int64 runtime·nanotime(void); // monotonic time
int64 runtime·unixnanotime(void); // real time, can skip
void runtime·dopanic(int32);
@ -868,7 +868,7 @@ void runtime·setcpuprofilerate(int32);
void runtime·usleep(uint32);
int64 runtime·cputicks(void);
int64 runtime·tickspersecond(void);
void runtime·blockevent(int64, int32);
void runtime·blockevent(int64, intgo);
G* runtime·netpoll(bool);
void runtime·netpollinit(void);
int32 runtime·netpollopen(uintptr, PollDesc*);

12
src/pkg/runtime/stack.c
View file

@ -477,6 +477,7 @@ copyabletopsegment(G *gp)
Func *f;
FuncVal *fn;
StackMap *stackmap;
bool (*cb)(Stkframe*, void*);
if(gp->stackbase == 0)
runtime·throw("stackbase == 0");
@ -486,7 +487,8 @@ copyabletopsegment(G *gp)
// Check that each frame is copyable. As a side effect,
// count the frames.
runtime·gentraceback(~(uintptr)0, ~(uintptr)0, 0, gp, 0, nil, 0x7fffffff, checkframecopy, &cinfo, false);
cb = checkframecopy;
runtime·gentraceback(~(uintptr)0, ~(uintptr)0, 0, gp, 0, nil, 0x7fffffff, &cb, &cinfo, false);
if(StackDebug >= 1 && cinfo.frames != -1)
runtime·printf("copystack: %d copyable frames\n", cinfo.frames);
@ -680,8 +682,10 @@ adjustframe(Stkframe *frame, void *arg)
// adjust inargs and outargs
if(frame->arglen != 0) {
stackmap = runtime·funcdata(f, FUNCDATA_ArgsPointerMaps);
if(stackmap == nil)
if(stackmap == nil) {
runtime·printf("size %d\n", (int32)frame->arglen);
runtime·throw("no arg info");
}
bv = runtime·stackmapdata(stackmap, pcdata);
if(StackDebug >= 3)
runtime·printf(" args\n");
@ -773,6 +777,7 @@ copystack(G *gp, uintptr nframes, uintptr newsize)
AdjustInfo adjinfo;
Stktop *oldtop, *newtop;
uint32 oldstatus;
bool (*cb)(Stkframe*, void*);
if(gp->syscallstack != 0)
runtime·throw("can't handle stack copy in syscall yet");
@ -797,7 +802,8 @@ copystack(G *gp, uintptr nframes, uintptr newsize)
adjinfo.oldstk = oldstk;
adjinfo.oldbase = oldbase;
adjinfo.delta = newbase - oldbase;
runtime·gentraceback(~(uintptr)0, ~(uintptr)0, 0, gp, 0, nil, nframes, adjustframe, &adjinfo, false);
cb = adjustframe;
runtime·gentraceback(~(uintptr)0, ~(uintptr)0, 0, gp, 0, nil, nframes, &cb, &adjinfo, false);
// adjust other miscellaneous things that have pointers into stacks.
adjustctxt(gp, &adjinfo);

20
src/pkg/runtime/stubs.go
View file

@ -12,6 +12,7 @@ import "unsafe"
// each function.
const ptrSize = 4 << (^uintptr(0) >> 63) // unsafe.Sizeof(uintptr(0)) but an ideal const
const regSize = 4 << (^uintreg(0) >> 63) // unsafe.Sizeof(uintreg(0)) but an ideal const
//go:noescape
func racereadpc(addr unsafe.Pointer, callpc, pc uintptr)
@ -141,7 +142,6 @@ func entersyscallblock()
func exitsyscall()
func goroutineheader(gp *g)
func traceback(pc, sp, lr uintptr, gp *g)
func tracebackothers(gp *g)
func cgocallback(fn, frame unsafe.Pointer, framesize uintptr)
@ -246,3 +246,21 @@ func asmcgocall(fn, arg unsafe.Pointer)
//go:noescape
func open(name *byte, mode, perm int32) int32
//go:noescape
func gotraceback(*bool) int32
func funcname(*_func) *byte
func gofuncname(f *_func) string {
return gostringnocopy(funcname(f))
}
const _NoArgs = ^uintptr(0)
var newproc, deferproc, lessstack struct{} // C/assembly functions
func funcspdelta(*_func, uintptr) int32 // symtab.c
func funcarglen(*_func, uintptr) int32 // symtab.c
const _ArgsSizeUnknown = -0x80000000 // funcdata.h
func topofstack(*_func) bool // proc.c

504
src/pkg/runtime/traceback.go Normal file
View file

@ -0,0 +1,504 @@
// Copyright 2009 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.
package runtime
import "unsafe"
// The code in this file implements stack trace walking for all architectures.
// The most important fact about a given architecture is whether it uses a link register.
// On systems with link registers, the prologue for a non-leaf function stores the
// incoming value of LR at the bottom of the newly allocated stack frame.
// On systems without link registers, the architecture pushes a return PC during
// the call instruction, so the return PC ends up above the stack frame.
// In this file, the return PC is always called LR, no matter how it was found.
//
// To date, the opposite of a link register architecture is an x86 architecture.
// This code may need to change if some other kind of non-link-register
// architecture comes along.
//
// The other important fact is the size of a pointer: on 32-bit systems the LR
// takes up only 4 bytes on the stack, while on 64-bit systems it takes up 8 bytes.
// Typically this is ptrSize.
//
// As an exception, amd64p32 has ptrSize == 4 but the CALL instruction still
// stores an 8-byte return PC onto the stack. To accommodate this, we use regSize
// as the size of the architecture-pushed return PC.
//
// usesLR is defined below. ptrSize and regSize are defined in stubs.go.
const usesLR = GOARCH != "amd64" && GOARCH != "amd64p32" && GOARCH != "386"
// jmpdeferPC is the PC at the beginning of the jmpdefer assembly function.
// The traceback needs to recognize it on link register architectures.
var jmpdeferPC uintptr
func init() {
f := jmpdefer
jmpdeferPC = **(**uintptr)(unsafe.Pointer(&f))
}
// System-specific hook. See traceback_windows.go
var systraceback func(*_func, *stkframe, *g, bool, func(*stkframe, unsafe.Pointer) bool, unsafe.Pointer) (changed, aborted bool)
// Generic traceback. Handles runtime stack prints (pcbuf == nil),
// the runtime.Callers function (pcbuf != nil), as well as the garbage
// collector (callback != nil). A little clunky to merge these, but avoids
// duplicating the code and all its subtlety.
func gentraceback(pc0 uintptr, sp0 uintptr, lr0 uintptr, gp *g, skip int, pcbuf *uintptr, max int, callback func(*stkframe, unsafe.Pointer) bool, v unsafe.Pointer, printall bool) int {
g := getg()
gotraceback := gotraceback(nil)
if pc0 == ^uintptr(0) && sp0 == ^uintptr(0) { // Signal to fetch saved values from gp.
if gp.syscallstack != 0 {
pc0 = gp.syscallpc
sp0 = gp.syscallsp
if usesLR {
lr0 = 0
}
} else {
pc0 = gp.sched.pc
sp0 = gp.sched.sp
if usesLR {
lr0 = gp.sched.lr
}
}
}
nprint := 0
var frame stkframe
frame.pc = pc0
frame.sp = sp0
if usesLR {
frame.lr = lr0
}
waspanic := false
wasnewproc := false
printing := pcbuf == nil && callback == nil
panic := gp._panic
_defer := gp._defer
for _defer != nil && uintptr(_defer.argp) == _NoArgs {
_defer = _defer.link
}
for panic != nil && panic._defer == nil {
panic = panic.link
}
// If the PC is zero, it's likely a nil function call.
// Start in the caller's frame.
if frame.pc == 0 {
if usesLR {
frame.pc = *(*uintptr)(unsafe.Pointer(frame.sp))
frame.lr = 0
} else {
frame.pc = uintptr(*(*uintreg)(unsafe.Pointer(frame.sp)))
frame.sp += regSize
}
}
f := findfunc(frame.pc)
if f == nil {
if callback != nil {
print("runtime: unknown pc ", hex(frame.pc), "\n")
gothrow("unknown pc")
}
return 0
}
frame.fn = f
n := 0
stk := (*stktop)(unsafe.Pointer(gp.stackbase))
for n < max {
// Typically:
// pc is the PC of the running function.
// sp is the stack pointer at that program counter.
// fp is the frame pointer (caller's stack pointer) at that program counter, or nil if unknown.
// stk is the stack containing sp.
// The caller's program counter is lr, unless lr is zero, in which case it is *(uintptr*)sp.
if frame.pc == uintptr(unsafe.Pointer(&lessstack)) {
// Hit top of stack segment. Unwind to next segment.
frame.pc = stk.gobuf.pc
frame.sp = stk.gobuf.sp
frame.lr = 0
frame.fp = 0
if printing && showframe(nil, gp) {
print("----- stack segment boundary -----\n")
}
stk = (*stktop)(unsafe.Pointer(stk.stackbase))
f = findfunc(frame.pc)
if f == nil {
print("runtime: unknown pc ", hex(frame.pc), " after stack split\n")
if callback != nil {
gothrow("unknown pc")
}
}
frame.fn = f
continue
}
f = frame.fn
// Hook for handling Windows exception handlers. See traceback_windows.go.
if systraceback != nil {
changed, aborted := systraceback(f, (*stkframe)(noescape(unsafe.Pointer(&frame))), gp, printing, callback, v)
if aborted {
return n
}
if changed {
continue
}
}
// Found an actual function.
// Derive frame pointer and link register.
if frame.fp == 0 {
frame.fp = frame.sp + uintptr(funcspdelta(f, frame.pc))
if !usesLR {
// On x86, call instruction pushes return PC before entering new function.
frame.fp += regSize
}
}
var flr *_func
if topofstack(f) {
frame.lr = 0
flr = nil
} else if usesLR && f.entry == jmpdeferPC {
// jmpdefer modifies SP/LR/PC non-atomically.
// If a profiling interrupt arrives during jmpdefer,
// the stack unwind may see a mismatched register set
// and get confused. Stop if we see PC within jmpdefer
// to avoid that confusion.
// See golang.org/issue/8153.
if callback != nil {
gothrow("traceback_arm: found jmpdefer when tracing with callback")
}
frame.lr = 0
} else {
if usesLR {
if n == 0 && frame.sp < frame.fp || frame.lr == 0 {
frame.lr = *(*uintptr)(unsafe.Pointer(frame.sp))
}
} else {
if frame.lr == 0 {
frame.lr = uintptr(*(*uintreg)(unsafe.Pointer(frame.fp - regSize)))
}
}
flr = findfunc(frame.lr)
if flr == nil {
// This happens if you get a profiling interrupt at just the wrong time.
// In that context it is okay to stop early.
// But if callback is set, we're doing a garbage collection and must
// get everything, so crash loudly.
if callback != nil {
print("runtime: unexpected return pc for ", gofuncname(f), " called from ", hex(frame.lr), "\n")
gothrow("unknown caller pc")
}
}
}
frame.varp = frame.fp
if !usesLR {
// On x86, call instruction pushes return PC before entering new function.
frame.varp -= regSize
}
// Derive size of arguments.
// Most functions have a fixed-size argument block,
// so we can use metadata about the function f.
// Not all, though: there are some variadic functions
// in package runtime and reflect, and for those we use call-specific
// metadata recorded by f's caller.
if callback != nil || printing {
frame.argp = frame.fp
if usesLR {
frame.argp += ptrSize
}
if f.args != _ArgsSizeUnknown {
frame.arglen = uintptr(f.args)
} else if flr == nil {
frame.arglen = 0
} else if frame.lr == uintptr(unsafe.Pointer(&lessstack)) {
frame.arglen = uintptr(stk.argsize)
} else {
i := funcarglen(flr, frame.lr)
if i >= 0 {
frame.arglen = uintptr(i)
} else {
var tmp string
if flr != nil {
tmp = gofuncname(flr)
} else {
tmp = "?"
}
print("runtime: unknown argument frame size for ", gofuncname(f), " called from ", hex(frame.lr), " [", tmp, "]\n")
if callback != nil {
gothrow("invalid stack")
}
frame.arglen = 0
}
}
}
// Determine function SP where deferproc would find its arguments.
var sparg uintptr
if usesLR {
// On link register architectures, that's the standard bottom-of-stack plus 1 word
// for the saved LR. If the previous frame was a direct call to newproc/deferproc,
// however, the SP is three words lower than normal.
// If the function has no frame at all - perhaps it just started, or perhaps
// it is a leaf with no local variables - then we cannot possibly find its
// SP in a defer, and we might confuse its SP for its caller's SP, so
// leave sparg=0 in that case.
if frame.fp != frame.sp {
sparg = frame.sp + regSize
if wasnewproc {
sparg += 3 * regSize
}
}
} else {
// On x86 that's the standard bottom-of-stack, so SP exactly.
// If the previous frame was a direct call to newproc/deferproc, however,
// the SP is two words lower than normal.
sparg = frame.sp
if wasnewproc {
sparg += 2 * ptrSize
}
}
// Determine frame's 'continuation PC', where it can continue.
// Normally this is the return address on the stack, but if sigpanic
// is immediately below this function on the stack, then the frame
// stopped executing due to a trap, and frame.pc is probably not
// a safe point for looking up liveness information. In this panicking case,
// the function either doesn't return at all (if it has no defers or if the
// defers do not recover) or it returns from one of the calls to
// deferproc a second time (if the corresponding deferred func recovers).
// It suffices to assume that the most recent deferproc is the one that
// returns; everything live at earlier deferprocs is still live at that one.
frame.continpc = frame.pc
if waspanic {
if panic != nil && panic._defer.argp == sparg {
frame.continpc = panic._defer.pc
} else if _defer != nil && _defer.argp == sparg {
frame.continpc = _defer.pc
} else {
frame.continpc = 0
}
}
// Unwind our local panic & defer stacks past this frame.
for panic != nil && (panic._defer == nil || panic._defer.argp == sparg || panic._defer.argp == _NoArgs) {
panic = panic.link
}
for _defer != nil && (_defer.argp == sparg || _defer.argp == _NoArgs) {
_defer = _defer.link
}
if skip > 0 {
skip--
goto skipped
}
if pcbuf != nil {
(*[1 << 20]uintptr)(unsafe.Pointer(pcbuf))[n] = frame.pc
}
if callback != nil {
if !callback((*stkframe)(noescape(unsafe.Pointer(&frame))), v) {
return n
}
}
if printing {
if printall || showframe(f, gp) {
// Print during crash.
// main(0x1, 0x2, 0x3)
// /home/rsc/go/src/runtime/x.go:23 +0xf
//
tracepc := frame.pc // back up to CALL instruction for funcline.
if n > 0 && frame.pc > f.entry && !waspanic {
tracepc--
}
print(gofuncname(f), "(")
argp := (*[100]uintptr)(unsafe.Pointer(frame.argp))
for i := uintptr(0); i < frame.arglen/ptrSize; i++ {
if i >= 10 {
print(", ...")
break
}
if i != 0 {
print(", ")
}
print(hex(argp[i]))
}
print(")\n")
var file string
line := funcline(f, tracepc, &file)
print("\t", file, ":", line)
if frame.pc > f.entry {
print(" +", hex(frame.pc-f.entry))
}
if g.m.throwing > 0 && gp == g.m.curg || gotraceback >= 2 {
print(" fp=", hex(frame.fp), " sp=", hex(frame.sp))
}
print("\n")
nprint++
}
}
n++
skipped:
waspanic = f.entry == uintptr(unsafe.Pointer(&sigpanic))
wasnewproc = f.entry == uintptr(unsafe.Pointer(&newproc)) || f.entry == uintptr(unsafe.Pointer(&deferproc))
// Do not unwind past the bottom of the stack.
if flr == nil {
break
}
// Unwind to next frame.
frame.fn = flr
frame.pc = frame.lr
frame.lr = 0
frame.sp = frame.fp
frame.fp = 0
// On link register architectures, sighandler saves the LR on stack
// before faking a call to sigpanic.
if usesLR && waspanic {
x := *(*uintptr)(unsafe.Pointer(frame.sp))
frame.sp += ptrSize
f = findfunc(frame.pc)
frame.fn = f
if f == nil {
frame.pc = x
} else if f.frame == 0 {
frame.lr = x
}
}
}
if pcbuf == nil && callback == nil {
n = nprint
}
// If callback != nil, we're being called to gather stack information during
// garbage collection or stack growth. In that context, require that we used
// up the entire defer stack. If not, then there is a bug somewhere and the
// garbage collection or stack growth may not have seen the correct picture
// of the stack. Crash now instead of silently executing the garbage collection
// or stack copy incorrectly and setting up for a mysterious crash later.
//
// Note that panic != nil is okay here: there can be leftover panics,
// because the defers on the panic stack do not nest in frame order as
// they do on the defer stack. If you have:
//
// frame 1 defers d1
// frame 2 defers d2
// frame 3 defers d3
// frame 4 panics
// frame 4's panic starts running defers
// frame 5, running d3, defers d4
// frame 5 panics
// frame 5's panic starts running defers
// frame 6, running d4, garbage collects
// frame 6, running d2, garbage collects
//
// During the execution of d4, the panic stack is d4 -> d3, which
// is nested properly, and we'll treat frame 3 as resumable, because we
// can find d3. (And in fact frame 3 is resumable. If d4 recovers
// and frame 5 continues running, d3, d3 can recover and we'll
// resume execution in (returning from) frame 3.)
//
// During the execution of d2, however, the panic stack is d2 -> d3,
// which is inverted. The scan will match d2 to frame 2 but having
// d2 on the stack until then means it will not match d3 to frame 3.
// This is okay: if we're running d2, then all the defers after d2 have
// completed and their corresponding frames are dead. Not finding d3
// for frame 3 means we'll set frame 3's continpc == 0, which is correct
// (frame 3 is dead). At the end of the walk the panic stack can thus
// contain defers (d3 in this case) for dead frames. The inversion here
// always indicates a dead frame, and the effect of the inversion on the
// scan is to hide those dead frames, so the scan is still okay:
// what's left on the panic stack are exactly (and only) the dead frames.
//
// We require callback != nil here because only when callback != nil
// do we know that gentraceback is being called in a "must be correct"
// context as opposed to a "best effort" context. The tracebacks with
// callbacks only happen when everything is stopped nicely.
// At other times, such as when gathering a stack for a profiling signal
// or when printing a traceback during a crash, everything may not be
// stopped nicely, and the stack walk may not be able to complete.
// It's okay in those situations not to use up the entire defer stack:
// incomplete information then is still better than nothing.
if callback != nil && n < max && _defer != nil {
if _defer != nil {
print("runtime: g", gp.goid, ": leftover defer argp=", hex(_defer.argp), " pc=", hex(_defer.pc), "\n")
}
if panic != nil {
print("runtime: g", gp.goid, ": leftover panic argp=", hex(panic._defer.argp), " pc=", hex(panic._defer.pc), "\n")
}
for _defer = gp._defer; _defer != nil; _defer = _defer.link {
print("\tdefer ", _defer, " argp=", hex(_defer.argp), " pc=", hex(_defer.pc), "\n")
}
for panic = gp._panic; panic != nil; panic = panic.link {
print("\tpanic ", panic, " defer ", panic._defer)
if panic._defer != nil {
print(" argp=", hex(panic._defer.argp), " pc=", hex(panic._defer.pc))
}
print("\n")
}
gothrow("traceback has leftover defers or panics")
}
return n
}
func showframe(*_func, *g) bool
func printcreatedby(gp *g) {
// Show what created goroutine, except main goroutine (goid 1).
pc := gp.gopc
f := findfunc(pc)
if f != nil && showframe(f, gp) && gp.goid != 1 {
print("created by ", gofuncname(f), "\n")
tracepc := pc // back up to CALL instruction for funcline.
if pc > f.entry {
tracepc -= _PCQuantum
}
var file string
line := funcline(f, tracepc, &file)
print("\t", file, ":", line)
if pc > f.entry {
print(" +", hex(pc-f.entry))
}
print("\n")
}
}
func traceback(pc uintptr, sp uintptr, lr uintptr, gp *g) {
var n int
if readgstatus(gp)&^_Gscan == _Gsyscall {
// Override signal registers if blocked in system call.
pc = gp.syscallpc
sp = gp.syscallsp
}
// Print traceback. By default, omits runtime frames.
// If that means we print nothing at all, repeat forcing all frames printed.
n = gentraceback(pc, sp, 0, gp, 0, nil, _TracebackMaxFrames, nil, nil, false)
if n == 0 {
n = gentraceback(pc, sp, 0, gp, 0, nil, _TracebackMaxFrames, nil, nil, true)
}
if n == _TracebackMaxFrames {
print("...additional frames elided...\n")
}
printcreatedby(gp)
}
func callers(skip int, pcbuf *uintptr, m int) int {
sp := getcallersp(unsafe.Pointer(&skip))
pc := uintptr(getcallerpc(unsafe.Pointer(&skip)))
return gentraceback(pc, sp, 0, getg(), skip, pcbuf, m, nil, nil, false)
}
func gcallers(gp *g, skip int, pcbuf *uintptr, m int) int {
return gentraceback(^uintptr(0), ^uintptr(0), 0, gp, skip, pcbuf, m, nil, nil, false)
}

363
src/pkg/runtime/traceback_arm.c
View file

@ -1,363 +0,0 @@
// Copyright 2009 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.
#include "runtime.h"
#include "arch_GOARCH.h"
#include "malloc.h"
#include "funcdata.h"
void runtime·sigpanic(void);
void runtime·newproc(void);
void runtime·deferproc(void);
int32
runtime·gentraceback(uintptr pc0, uintptr sp0, uintptr lr0, G *gp, int32 skip, uintptr *pcbuf, int32 max, bool (*callback)(Stkframe*, void*), void *v, bool printall)
{
int32 i, n, nprint, line, gotraceback;
uintptr x, tracepc, sparg;
bool waspanic, wasnewproc, printing;
Func *f, *flr;
Stkframe frame;
Stktop *stk;
String file;
Panic *panic;
Defer *defer;
gotraceback = runtime·gotraceback(nil);
if(pc0 == ~(uintptr)0 && sp0 == ~(uintptr)0) { // Signal to fetch saved values from gp.
if(gp->syscallstack != (uintptr)nil) {
pc0 = gp->syscallpc;
sp0 = gp->syscallsp;
lr0 = 0;
} else {
pc0 = gp->sched.pc;
sp0 = gp->sched.sp;
lr0 = gp->sched.lr;
}
}
nprint = 0;
runtime·memclr((byte*)&frame, sizeof frame);
frame.pc = pc0;
frame.lr = lr0;
frame.sp = sp0;
waspanic = false;
wasnewproc = false;
printing = pcbuf==nil && callback==nil;
panic = gp->panic;
defer = gp->defer;
while(defer != nil && defer->argp == NoArgs)
defer = defer->link;
while(panic != nil && panic->defer == nil)
panic = panic->link;
// If the PC is zero, it's likely a nil function call.
// Start in the caller's frame.
if(frame.pc == 0) {
frame.pc = frame.lr;
frame.lr = 0;
}
f = runtime·findfunc(frame.pc);
if(f == nil) {
if(callback != nil) {
runtime·printf("runtime: unknown pc %p\n", frame.pc);
runtime·throw("unknown pc");
}
return 0;
}
frame.fn = f;
n = 0;
stk = (Stktop*)gp->stackbase;
while(n < max) {
// Typically:
// pc is the PC of the running function.
// sp is the stack pointer at that program counter.
// fp is the frame pointer (caller's stack pointer) at that program counter, or nil if unknown.
// stk is the stack containing sp.
// The caller's program counter is lr, unless lr is zero, in which case it is *(uintptr*)sp.
if(frame.pc == (uintptr)runtime·lessstack) {
// Hit top of stack segment. Unwind to next segment.
frame.pc = stk->gobuf.pc;
frame.sp = stk->gobuf.sp;
frame.lr = 0;
frame.fp = 0;
if(printing && runtime·showframe(nil, gp))
runtime·printf("----- stack segment boundary -----\n");
stk = (Stktop*)stk->stackbase;
f = runtime·findfunc(frame.pc);
if(f == nil) {
runtime·printf("runtime: unknown pc %p after stack split\n", frame.pc);
if(callback != nil)
runtime·throw("unknown pc");
}
frame.fn = f;
continue;
}
f = frame.fn;
// Found an actual function.
// Derive frame pointer and link register.
if(frame.fp == 0)
frame.fp = frame.sp + runtime·funcspdelta(f, frame.pc);
if(runtime·topofstack(f)) {
frame.lr = 0;
flr = nil;
} else if(f->entry == (uintptr)runtime·jmpdefer) {
// jmpdefer modifies SP/LR/PC non-atomically.
// If a profiling interrupt arrives during jmpdefer,
// the stack unwind may see a mismatched register set
// and get confused. Stop if we see PC within jmpdefer
// to avoid that confusion.
// See golang.org/issue/8153.
// This check can be deleted if jmpdefer is changed
// to restore all three atomically using pop.
if(callback != nil)
runtime·throw("traceback_arm: found jmpdefer when tracing with callback");
frame.lr = 0;
flr = nil;
} else {
if((n == 0 && frame.sp < frame.fp) || frame.lr == 0)
frame.lr = *(uintptr*)frame.sp;
flr = runtime·findfunc(frame.lr);
if(flr == nil) {
// This happens if you get a profiling interrupt at just the wrong time.
// In that context it is okay to stop early.
// But if callback is set, we're doing a garbage collection and must
// get everything, so crash loudly.
if(callback != nil) {
runtime·printf("runtime: unexpected return pc for %s called from %p\n", runtime·funcname(f), frame.lr);
runtime·throw("unknown caller pc");
}
}
}
frame.varp = frame.fp;
// Derive size of arguments.
// Most functions have a fixed-size argument block,
// so we can use metadata about the function f.
// Not all, though: there are some variadic functions
// in package runtime and reflect, and for those we use call-specific
// metadata recorded by f's caller.
if(callback != nil || printing) {
frame.argp = frame.fp + sizeof(uintptr);
if(f->args != ArgsSizeUnknown)
frame.arglen = f->args;
else if(flr == nil)
frame.arglen = 0;
else if(frame.lr == (uintptr)runtime·lessstack)
frame.arglen = stk->argsize;
else if((i = runtime·funcarglen(flr, frame.lr)) >= 0)
frame.arglen = i;
else {
runtime·printf("runtime: unknown argument frame size for %s called from %p [%s]\n",
runtime·funcname(f), frame.lr, flr ? runtime·funcname(flr) : "?");
if(callback != nil)
runtime·throw("invalid stack");
frame.arglen = 0;
}
}
// Determine function SP where deferproc would find its arguments.
// On ARM that's just the standard bottom-of-stack plus 1 word for
// the saved LR. If the previous frame was a direct call to newproc/deferproc,
// however, the SP is three words lower than normal.
// If the function has no frame at all - perhaps it just started, or perhaps
// it is a leaf with no local variables - then we cannot possibly find its
// SP in a defer, and we might confuse its SP for its caller's SP, so
// set sparg=0 in that case.
sparg = 0;
if(frame.fp != frame.sp) {
sparg = frame.sp + sizeof(uintreg);
if(wasnewproc)
sparg += 3*sizeof(uintreg);
}
// Determine frame's 'continuation PC', where it can continue.
// Normally this is the return address on the stack, but if sigpanic
// is immediately below this function on the stack, then the frame
// stopped executing due to a trap, and frame.pc is probably not
// a safe point for looking up liveness information. In this panicking case,
// the function either doesn't return at all (if it has no defers or if the
// defers do not recover) or it returns from one of the calls to
// deferproc a second time (if the corresponding deferred func recovers).
// It suffices to assume that the most recent deferproc is the one that
// returns; everything live at earlier deferprocs is still live at that one.
frame.continpc = frame.pc;
if(waspanic) {
if(panic != nil && panic->defer->argp == sparg)
frame.continpc = (uintptr)panic->defer->pc;
else if(defer != nil && defer->argp == sparg)
frame.continpc = (uintptr)defer->pc;
else
frame.continpc = 0;
}
// Unwind our local panic & defer stacks past this frame.
while(panic != nil && (panic->defer == nil || panic->defer->argp == sparg || panic->defer->argp == NoArgs))
panic = panic->link;
while(defer != nil && (defer->argp == sparg || defer->argp == NoArgs))
defer = defer->link;
if(skip > 0) {
skip--;
goto skipped;
}
if(pcbuf != nil)
pcbuf[n] = frame.pc;
if(callback != nil) {
if(!callback(&frame, v))
return n;
}
if(printing) {
if(printall || runtime·showframe(f, gp)) {
// Print during crash.
// main(0x1, 0x2, 0x3)
// /home/rsc/go/src/runtime/x.go:23 +0xf
tracepc = frame.pc; // back up to CALL instruction for funcline.
if(n > 0 && frame.pc > f->entry && !waspanic)
tracepc -= sizeof(uintptr);
runtime·printf("%s(", runtime·funcname(f));
for(i = 0; i < frame.arglen/sizeof(uintptr); i++) {
if(i >= 10) {
runtime·prints(", ...");
break;
}
if(i != 0)
runtime·prints(", ");
runtime·printhex(((uintptr*)frame.argp)[i]);
}
runtime·prints(")\n");
line = runtime·funcline(f, tracepc, &file);
runtime·printf("\t%S:%d", file, line);
if(frame.pc > f->entry)
runtime·printf(" +%p", (uintptr)(frame.pc - f->entry));
if(g->m->throwing > 0 && gp == g->m->curg || gotraceback >= 2)
runtime·printf(" fp=%p sp=%p", frame.fp, frame.sp);
runtime·printf("\n");
nprint++;
}
}
n++;
skipped:
waspanic = f->entry == (uintptr)runtime·sigpanic;
wasnewproc = f->entry == (uintptr)runtime·newproc || f->entry == (uintptr)runtime·deferproc;
// Do not unwind past the bottom of the stack.
if(flr == nil)
break;
// Unwind to next frame.
frame.pc = frame.lr;
frame.fn = flr;
frame.lr = 0;
frame.sp = frame.fp;
frame.fp = 0;
// sighandler saves the lr on stack before faking a call to sigpanic
if(waspanic) {
x = *(uintptr*)frame.sp;
frame.sp += 4;
frame.fn = f = runtime·findfunc(frame.pc);
if(f == nil)
frame.pc = x;
else if(f->frame == 0)
frame.lr = x;
}
}
if(pcbuf == nil && callback == nil)
n = nprint;
// For rationale, see long comment in traceback_x86.c.
if(callback != nil && n < max && defer != nil) {
if(defer != nil)
runtime·printf("runtime: g%D: leftover defer argp=%p pc=%p\n", gp->goid, defer->argp, defer->pc);
if(panic != nil)
runtime·printf("runtime: g%D: leftover panic argp=%p pc=%p\n", gp->goid, panic->defer->argp, panic->defer->pc);
for(defer = gp->defer; defer != nil; defer = defer->link)
runtime·printf("\tdefer %p argp=%p pc=%p\n", defer, defer->argp, defer->pc);
for(panic = gp->panic; panic != nil; panic = panic->link) {
runtime·printf("\tpanic %p defer %p", panic, panic->defer);
if(panic->defer != nil)
runtime·printf(" argp=%p pc=%p", panic->defer->argp, panic->defer->pc);
runtime·printf("\n");
}
runtime·throw("traceback has leftover defers or panics");
}
return n;
}
void
runtime·printcreatedby(G *gp)
{
int32 line;
uintptr pc, tracepc;
Func *f;
String file;
// Show what created goroutine, except main goroutine (goid 1).
if((pc = gp->gopc) != 0 && (f = runtime·findfunc(pc)) != nil &&
runtime·showframe(f, gp) && gp->goid != 1) {
runtime·printf("created by %s\n", runtime·funcname(f));
tracepc = pc; // back up to CALL instruction for funcline.
if(pc > f->entry)
tracepc -= PCQuantum;
line = runtime·funcline(f, tracepc, &file);
runtime·printf("\t%S:%d", file, line);
if(pc > f->entry)
runtime·printf(" +%p", (uintptr)(pc - f->entry));
runtime·printf("\n");
}
}
void
runtime·traceback(uintptr pc, uintptr sp, uintptr lr, G *gp)
{
int32 n;
if((runtime·readgstatus(gp)&~Gscan) == Gsyscall){
// Override signal registers if blocked in system call.
pc = gp->syscallpc;
sp = gp->syscallsp;
lr = 0;
}
// Print traceback. By default, omits runtime frames.
// If that means we print nothing at all, repeat forcing all frames printed.
n = runtime·gentraceback(pc, sp, lr, gp, 0, nil, TracebackMaxFrames, nil, nil, false);
if(n == 0)
runtime·gentraceback(pc, sp, lr, gp, 0, nil, TracebackMaxFrames, nil, nil, true);
if(n == TracebackMaxFrames)
runtime·printf("...additional frames elided...\n");
runtime·printcreatedby(gp);
}
// func caller(n int) (pc uintptr, file string, line int, ok bool)
int32
runtime·callers(int32 skip, uintptr *pcbuf, int32 m)
{
uintptr pc, sp;
sp = runtime·getcallersp(&skip);
pc = (uintptr)runtime·getcallerpc(&skip);
return runtime·gentraceback(pc, sp, 0, g, skip, pcbuf, m, nil, nil, false);
}
int32
runtime·gcallers(G *gp, int32 skip, uintptr *pcbuf, int32 m)
{
return runtime·gentraceback(~(uintptr)0, ~(uintptr)0, 0, gp, skip, pcbuf, m, nil, nil, false);
}

64
src/pkg/runtime/traceback_windows.go Normal file
View file

@ -0,0 +1,64 @@
// Copyright 2009 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.
package runtime
import "unsafe"
// sigtrampPC is the PC at the beginning of the jmpdefer assembly function.
// The traceback needs to recognize it on link register architectures.
var sigtrampPC uintptr
var sigtramp struct{} // assembly function
func init() {
f := sigtramp
sigtrampPC = **(**uintptr)(unsafe.Pointer(&f))
systraceback = traceback_windows
}
func traceback_windows(f *_func, frame *stkframe, gp *g, printing bool, callback func(*stkframe, unsafe.Pointer) bool, v unsafe.Pointer) (changed, aborted bool) {
// The main traceback thinks it has found a function. Check this.
// Windows exception handlers run on the actual g stack (there is room
// dedicated to this below the usual "bottom of stack"), not on a separate
// stack. As a result, we have to be able to unwind past the exception
// handler when called to unwind during stack growth inside the handler.
// Recognize the frame at the call to sighandler in sigtramp and unwind
// using the context argument passed to the call. This is awful.
if f != nil && f.entry == sigtrampPC && frame.pc > f.entry {
var r *context
// Invoke callback so that stack copier sees an uncopyable frame.
if callback != nil {
frame.continpc = frame.pc
frame.argp = 0
frame.arglen = 0
if !callback(frame, v) {
aborted = true
return
}
}
r = (*context)(unsafe.Pointer(frame.sp + ptrSize))
frame.pc = contextPC(r)
frame.sp = contextSP(r)
frame.lr = 0
frame.fp = 0
frame.fn = nil
if printing && showframe(nil, gp) {
print("----- exception handler -----\n")
}
f = findfunc(frame.pc)
if f == nil {
print("runtime: unknown pc ", hex(frame.pc), " after exception handler\n")
if callback != nil {
gothrow("unknown pc")
}
}
frame.fn = f
changed = true
return
}
return
}

436
src/pkg/runtime/traceback_x86.c
View file

@ -1,436 +0,0 @@
// Copyright 2009 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.
// +build amd64 amd64p32 386
#include "runtime.h"
#include "arch_GOARCH.h"
#include "malloc.h"
#include "funcdata.h"
#ifdef GOOS_windows
#include "defs_GOOS_GOARCH.h"
#endif
void runtime·sigpanic(void);
void runtime·newproc(void);
void runtime·deferproc(void);
#ifdef GOOS_windows
void runtime·sigtramp(void);
#endif
// This code is also used for the 386 tracebacks.
// Use uintptr for an appropriate word-sized integer.
// Generic traceback. Handles runtime stack prints (pcbuf == nil),
// the runtime.Callers function (pcbuf != nil), as well as the garbage
// collector (callback != nil). A little clunky to merge these, but avoids
// duplicating the code and all its subtlety.
int32
runtime·gentraceback(uintptr pc0, uintptr sp0, uintptr lr0, G *gp, int32 skip, uintptr *pcbuf, int32 max, bool (*callback)(Stkframe*, void*), void *v, bool printall)
{
int32 i, n, nprint, line, gotraceback;
uintptr tracepc, sparg;
bool waspanic, wasnewproc, printing;
Func *f, *flr;
Stkframe frame;
Stktop *stk;
String file;
Panic *panic;
Defer *defer;
USED(lr0);
gotraceback = runtime·gotraceback(nil);
if(pc0 == ~(uintptr)0 && sp0 == ~(uintptr)0) { // Signal to fetch saved values from gp.
if(gp->syscallstack != (uintptr)nil) {
pc0 = gp->syscallpc;
sp0 = gp->syscallsp;
} else {
pc0 = gp->sched.pc;
sp0 = gp->sched.sp;
}
}
nprint = 0;
runtime·memclr((byte*)&frame, sizeof frame);
frame.pc = pc0;
frame.sp = sp0;
waspanic = false;
wasnewproc = false;
printing = pcbuf==nil && callback==nil;
panic = gp->panic;
defer = gp->defer;
while(defer != nil && defer->argp == NoArgs)
defer = defer->link;
while(panic != nil && panic->defer == nil)
panic = panic->link;
// If the PC is zero, it's likely a nil function call.
// Start in the caller's frame.
if(frame.pc == 0) {
frame.pc = *(uintptr*)frame.sp;
frame.sp += sizeof(uintreg);
}
f = runtime·findfunc(frame.pc);
if(f == nil) {
if(callback != nil) {
runtime·printf("runtime: unknown pc %p\n", frame.pc);
runtime·throw("unknown pc");
}
return 0;
}
frame.fn = f;
n = 0;
stk = (Stktop*)gp->stackbase;
while(n < max) {
// Typically:
// pc is the PC of the running function.
// sp is the stack pointer at that program counter.
// fp is the frame pointer (caller's stack pointer) at that program counter, or nil if unknown.
// stk is the stack containing sp.
// The caller's program counter is lr, unless lr is zero, in which case it is *(uintptr*)sp.
if(frame.pc == (uintptr)runtime·lessstack) {
// Hit top of stack segment. Unwind to next segment.
frame.pc = stk->gobuf.pc;
frame.sp = stk->gobuf.sp;
frame.lr = 0;
frame.fp = 0;
frame.fn = nil;
if(printing && runtime·showframe(nil, gp))
runtime·printf("----- stack segment boundary -----\n");
stk = (Stktop*)stk->stackbase;
f = runtime·findfunc(frame.pc);
if(f == nil) {
runtime·printf("runtime: unknown pc %p after stack split\n", frame.pc);
if(callback != nil)
runtime·throw("unknown pc");
}
frame.fn = f;
continue;
}
f = frame.fn;
#ifdef GOOS_windows
// Windows exception handlers run on the actual g stack (there is room
// dedicated to this below the usual "bottom of stack"), not on a separate
// stack. As a result, we have to be able to unwind past the exception
// handler when called to unwind during stack growth inside the handler.
// Recognize the frame at the call to sighandler in sigtramp and unwind
// using the context argument passed to the call. This is awful.
if(f != nil && f->entry == (uintptr)runtime·sigtramp && frame.pc > f->entry) {
Context *r;
// Invoke callback so that stack copier sees an uncopyable frame.
if(callback != nil) {
frame.continpc = frame.pc;
frame.argp = 0;
frame.arglen = 0;
if(!callback(&frame, v))
return n;
}
r = (Context*)((uintptr*)frame.sp)[1];
#ifdef GOARCH_amd64
frame.pc = r->Rip;
frame.sp = r->Rsp;
#else
frame.pc = r->Eip;
frame.sp = r->Esp;
#endif
frame.lr = 0;
frame.fp = 0;
frame.fn = nil;
if(printing && runtime·showframe(nil, gp))
runtime·printf("----- exception handler -----\n");
f = runtime·findfunc(frame.pc);
if(f == nil) {
runtime·printf("runtime: unknown pc %p after exception handler\n", frame.pc);
if(callback != nil)
runtime·throw("unknown pc");
}
frame.fn = f;
continue;
}
#endif
// Found an actual function.
// Derive frame pointer and link register.
if(frame.fp == 0) {
frame.fp = frame.sp + runtime·funcspdelta(f, frame.pc);
frame.fp += sizeof(uintreg); // caller PC
}
if(runtime·topofstack(f)) {
frame.lr = 0;
flr = nil;
} else {
if(frame.lr == 0)
frame.lr = ((uintreg*)frame.fp)[-1];
flr = runtime·findfunc(frame.lr);
if(flr == nil) {
runtime·printf("runtime: unexpected return pc for %s called from %p\n", runtime·funcname(f), frame.lr);
if(callback != nil)
runtime·throw("unknown caller pc");
}
}
frame.varp = frame.fp - sizeof(uintreg);
// Derive size of arguments.
// Most functions have a fixed-size argument block,
// so we can use metadata about the function f.
// Not all, though: there are some variadic functions
// in package runtime and reflect, and for those we use call-specific
// metadata recorded by f's caller.
if(callback != nil || printing) {
frame.argp = frame.fp;
if(f->args != ArgsSizeUnknown)
frame.arglen = f->args;
else if(flr == nil)
frame.arglen = 0;
else if(frame.lr == (uintptr)runtime·lessstack)
frame.arglen = stk->argsize;
else if((i = runtime·funcarglen(flr, frame.lr)) >= 0)
frame.arglen = i;
else {
runtime·printf("runtime: unknown argument frame size for %s called from %p [%s]\n",
runtime·funcname(f), frame.lr, flr ? runtime·funcname(flr) : "?");
if(callback != nil)
runtime·throw("invalid stack");
frame.arglen = 0;
}
}
// Determine function SP where deferproc would find its arguments.
// On x86 that's just the standard bottom-of-stack, so SP exactly.
// If the previous frame was a direct call to newproc/deferproc, however,
// the SP is two words lower than normal.
sparg = frame.sp;
if(wasnewproc)
sparg += 2*sizeof(uintptr);
// Determine frame's 'continuation PC', where it can continue.
// Normally this is the return address on the stack, but if sigpanic
// is immediately below this function on the stack, then the frame
// stopped executing due to a trap, and frame.pc is probably not
// a safe point for looking up liveness information. In this panicking case,
// the function either doesn't return at all (if it has no defers or if the
// defers do not recover) or it returns from one of the calls to
// deferproc a second time (if the corresponding deferred func recovers).
// It suffices to assume that the most recent deferproc is the one that
// returns; everything live at earlier deferprocs is still live at that one.
frame.continpc = frame.pc;
if(waspanic) {
if(panic != nil && panic->defer->argp == sparg)
frame.continpc = panic->defer->pc;
else if(defer != nil && defer->argp == sparg)
frame.continpc = defer->pc;
else
frame.continpc = 0;
}
// Unwind our local panic & defer stacks past this frame.
while(panic != nil && (panic->defer == nil || panic->defer->argp == sparg || panic->defer->argp == NoArgs))
panic = panic->link;
while(defer != nil && (defer->argp == sparg || defer->argp == NoArgs))
defer = defer->link;
if(skip > 0) {
skip--;
goto skipped;
}
if(pcbuf != nil)
pcbuf[n] = frame.pc;
if(callback != nil) {
if(!callback(&frame, v))
return n;
}
if(printing) {
if(printall || runtime·showframe(f, gp)) {
// Print during crash.
// main(0x1, 0x2, 0x3)
// /home/rsc/go/src/runtime/x.go:23 +0xf
//
tracepc = frame.pc; // back up to CALL instruction for funcline.
if(n > 0 && frame.pc > f->entry && !waspanic)
tracepc--;
runtime·printf("%s(", runtime·funcname(f));
for(i = 0; i < frame.arglen/sizeof(uintptr); i++) {
if(i >= 10) {
runtime·prints(", ...");
break;
}
if(i != 0)
runtime·prints(", ");
runtime·printhex(((uintptr*)frame.argp)[i]);
}
runtime·prints(")\n");
line = runtime·funcline(f, tracepc, &file);
runtime·printf("\t%S:%d", file, line);
if(frame.pc > f->entry)
runtime·printf(" +%p", (uintptr)(frame.pc - f->entry));
if(g->m->throwing > 0 && gp == g->m->curg || gotraceback >= 2)
runtime·printf(" fp=%p sp=%p", frame.fp, frame.sp);
runtime·printf("\n");
nprint++;
}
}
n++;
skipped:
waspanic = f->entry == (uintptr)runtime·sigpanic;
wasnewproc = f->entry == (uintptr)runtime·newproc || f->entry == (uintptr)runtime·deferproc;
// Do not unwind past the bottom of the stack.
if(flr == nil)
break;
// Unwind to next frame.
frame.fn = flr;
frame.pc = frame.lr;
frame.lr = 0;
frame.sp = frame.fp;
frame.fp = 0;
}
if(pcbuf == nil && callback == nil)
n = nprint;
// If callback != nil, we're being called to gather stack information during
// garbage collection or stack growth. In that context, require that we used
// up the entire defer stack. If not, then there is a bug somewhere and the
// garbage collection or stack growth may not have seen the correct picture
// of the stack. Crash now instead of silently executing the garbage collection
// or stack copy incorrectly and setting up for a mysterious crash later.
//
// Note that panic != nil is okay here: there can be leftover panics,
// because the defers on the panic stack do not nest in frame order as
// they do on the defer stack. If you have:
//
// frame 1 defers d1
// frame 2 defers d2
// frame 3 defers d3
// frame 4 panics
// frame 4's panic starts running defers
// frame 5, running d3, defers d4
// frame 5 panics
// frame 5's panic starts running defers
// frame 6, running d4, garbage collects
// frame 6, running d2, garbage collects
//
// During the execution of d4, the panic stack is d4 -> d3, which
// is nested properly, and we'll treat frame 3 as resumable, because we
// can find d3. (And in fact frame 3 is resumable. If d4 recovers
// and frame 5 continues running, d3, d3 can recover and we'll
// resume execution in (returning from) frame 3.)
//
// During the execution of d2, however, the panic stack is d2 -> d3,
// which is inverted. The scan will match d2 to frame 2 but having
// d2 on the stack until then means it will not match d3 to frame 3.
// This is okay: if we're running d2, then all the defers after d2 have
// completed and their corresponding frames are dead. Not finding d3
// for frame 3 means we'll set frame 3's continpc == 0, which is correct
// (frame 3 is dead). At the end of the walk the panic stack can thus
// contain defers (d3 in this case) for dead frames. The inversion here
// always indicates a dead frame, and the effect of the inversion on the
// scan is to hide those dead frames, so the scan is still okay:
// what's left on the panic stack are exactly (and only) the dead frames.
//
// We require callback != nil here because only when callback != nil
// do we know that gentraceback is being called in a "must be correct"
// context as opposed to a "best effort" context. The tracebacks with
// callbacks only happen when everything is stopped nicely.
// At other times, such as when gathering a stack for a profiling signal
// or when printing a traceback during a crash, everything may not be
// stopped nicely, and the stack walk may not be able to complete.
// It's okay in those situations not to use up the entire defer stack:
// incomplete information then is still better than nothing.
if(callback != nil && n < max && defer != nil) {
if(defer != nil)
runtime·printf("runtime: g%D: leftover defer argp=%p pc=%p\n", gp->goid, defer->argp, defer->pc);
if(panic != nil)
runtime·printf("runtime: g%D: leftover panic argp=%p pc=%p\n", gp->goid, panic->defer->argp, panic->defer->pc);
for(defer = gp->defer; defer != nil; defer = defer->link)
runtime·printf("\tdefer %p argp=%p pc=%p\n", defer, defer->argp, defer->pc);
for(panic = gp->panic; panic != nil; panic = panic->link) {
runtime·printf("\tpanic %p defer %p", panic, panic->defer);
if(panic->defer != nil)
runtime·printf(" argp=%p pc=%p", panic->defer->argp, panic->defer->pc);
runtime·printf("\n");
}
runtime·throw("traceback has leftover defers or panics");
}
return n;
}
void
runtime·printcreatedby(G *gp)
{
int32 line;
uintptr pc, tracepc;
Func *f;
String file;
// Show what created goroutine, except main goroutine (goid 1).
if((pc = gp->gopc) != 0 && (f = runtime·findfunc(pc)) != nil &&
runtime·showframe(f, gp) && gp->goid != 1) {
runtime·printf("created by %s\n", runtime·funcname(f));
tracepc = pc; // back up to CALL instruction for funcline.
if(pc > f->entry)
tracepc -= PCQuantum;
line = runtime·funcline(f, tracepc, &file);
runtime·printf("\t%S:%d", file, line);
if(pc > f->entry)
runtime·printf(" +%p", (uintptr)(pc - f->entry));
runtime·printf("\n");
}
}
void
runtime·traceback(uintptr pc, uintptr sp, uintptr lr, G *gp)
{
int32 n;
USED(lr);
if((runtime·readgstatus(gp)&~Gscan) == Gsyscall){
// Override signal registers if blocked in system call.
pc = gp->syscallpc;
sp = gp->syscallsp;
}
// Print traceback. By default, omits runtime frames.
// If that means we print nothing at all, repeat forcing all frames printed.
n = runtime·gentraceback(pc, sp, 0, gp, 0, nil, TracebackMaxFrames, nil, nil, false);
if(n == 0)
n = runtime·gentraceback(pc, sp, 0, gp, 0, nil, TracebackMaxFrames, nil, nil, true);
if(n == TracebackMaxFrames)
runtime·printf("...additional frames elided...\n");
runtime·printcreatedby(gp);
}
int32
runtime·callers(int32 skip, uintptr *pcbuf, int32 m)
{
uintptr pc, sp;
sp = runtime·getcallersp(&skip);
pc = (uintptr)runtime·getcallerpc(&skip);
return runtime·gentraceback(pc, sp, 0, g, skip, pcbuf, m, nil, nil, false);
}
int32
runtime·gcallers(G *gp, int32 skip, uintptr *pcbuf, int32 m)
{
return runtime·gentraceback(~(uintptr)0, ~(uintptr)0, 0, gp, skip, pcbuf, m, nil, nil, false);
}