// 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 (
"runtime/internal/atomic"
"runtime/internal/sys"
"unsafe"
)
// Keep a cached value to make gotraceback fast,
// since we call it on every call to gentraceback.
// The cached value is a uint32 in which the low bits
// are the "crash" and "all" settings and the remaining
// bits are the traceback value (0 off, 1 on, 2 include system).
const (
tracebackCrash = 1 << iota
tracebackAll
tracebackShift = iota
)
var traceback_cache uint32 = 2 << tracebackShift
var traceback_env uint32
// gotraceback returns the current traceback settings.
//
// If level is 0, suppress all tracebacks.
// If level is 1, show tracebacks, but exclude runtime frames.
// If level is 2, show tracebacks including runtime frames.
// If all is set, print all goroutine stacks. Otherwise, print just the current goroutine.
// If crash is set, crash (core dump, etc) after tracebacking.
//
//go:nosplit
func gotraceback() (level int32, all, crash bool) {
_g_ := getg()
t := atomic.Load(&traceback_cache)
crash = t&tracebackCrash != 0
all = _g_.m.throwing > 0 || t&tracebackAll != 0
if _g_.m.traceback != 0 {
level = int32(_g_.m.traceback)
} else {
level = int32(t >> tracebackShift)
}
return
}
var (
argc int32
argv **byte
)
// nosplit for use in linux startup sysargs
//go:nosplit
func argv_index(argv **byte, i int32) *byte {
return *(**byte)(add(unsafe.Pointer(argv), uintptr(i)*sys.PtrSize))
}
func args(c int32, v **byte) {
argc = c
argv = v
sysargs(c, v)
}
func goargs() {
if GOOS == "windows" {
return
}
argslice = make([]string, argc)
for i := int32(0); i < argc; i++ {
argslice[i] = gostringnocopy(argv_index(argv, i))
}
}
func goenvs_unix() {
// TODO(austin): ppc64 in dynamic linking mode doesn't
// guarantee env[] will immediately follow argv. Might cause
// problems.
n := int32(0)
for argv_index(argv, argc+1+n) != nil {
n++
}
envs = make([]string, n)
for i := int32(0); i < n; i++ {
envs[i] = gostring(argv_index(argv, argc+1+i))
}
}
func environ() []string {
return envs
}
// TODO: These should be locals in testAtomic64, but we don't 8-byte
// align stack variables on 386.
var test_z64, test_x64 uint64
func testAtomic64() {
test_z64 = 42
test_x64 = 0
if atomic.Cas64(&test_z64, test_x64, 1) {
throw("cas64 failed")
}
if test_x64 != 0 {
throw("cas64 failed")
}
test_x64 = 42
if !atomic.Cas64(&test_z64, test_x64, 1) {
throw("cas64 failed")
}
if test_x64 != 42 || test_z64 != 1 {
throw("cas64 failed")
}
if atomic.Load64(&test_z64) != 1 {
throw("load64 failed")
}
atomic.Store64(&test_z64, (1<<40)+1)
if atomic.Load64(&test_z64) != (1<<40)+1 {
throw("store64 failed")
}
if atomic.Xadd64(&test_z64, (1<<40)+1) != (2<<40)+2 {
throw("xadd64 failed")
}
if atomic.Load64(&test_z64) != (2<<40)+2 {
throw("xadd64 failed")
}
if atomic.Xchg64(&test_z64, (3<<40)+3) != (2<<40)+2 {
throw("xchg64 failed")
}
if atomic.Load64(&test_z64) != (3<<40)+3 {
throw("xchg64 failed")
}
}
func check() {
var (
a int8
b uint8
c int16
d uint16
e int32
f uint32
g int64
h uint64
i, i1 float32
j, j1 float64
k unsafe.Pointer
l *uint16
m [4]byte
)
type x1t struct {
x uint8
}
type y1t struct {
x1 x1t
y uint8
}
var x1 x1t
var y1 y1t
if unsafe.Sizeof(a) != 1 {
throw("bad a")
}
if unsafe.Sizeof(b) != 1 {
throw("bad b")
}
if unsafe.Sizeof(c) != 2 {
throw("bad c")
}
if unsafe.Sizeof(d) != 2 {
throw("bad d")
}
if unsafe.Sizeof(e) != 4 {
throw("bad e")
}
if unsafe.Sizeof(f) != 4 {
throw("bad f")
}
if unsafe.Sizeof(g) != 8 {
throw("bad g")
}
if unsafe.Sizeof(h) != 8 {
throw("bad h")
}
if unsafe.Sizeof(i) != 4 {
throw("bad i")
}
if unsafe.Sizeof(j) != 8 {
throw("bad j")
}
if unsafe.Sizeof(k) != sys.PtrSize {
throw("bad k")
}
if unsafe.Sizeof(l) != sys.PtrSize {
throw("bad l")
}
if unsafe.Sizeof(x1) != 1 {
throw("bad unsafe.Sizeof x1")
}
if unsafe.Offsetof(y1.y) != 1 {
throw("bad offsetof y1.y")
}
if unsafe.Sizeof(y1) != 2 {
throw("bad unsafe.Sizeof y1")
}
if timediv(12345*1000000000+54321, 1000000000, &e) != 12345 || e != 54321 {
throw("bad timediv")
}
var z uint32
z = 1
if !atomic.Cas(&z, 1, 2) {
throw("cas1")
}
if z != 2 {
throw("cas2")
}
z = 4
if atomic.Cas(&z, 5, 6) {
throw("cas3")
}
if z != 4 {
throw("cas4")
}
z = 0xffffffff
if !atomic.Cas(&z, 0xffffffff, 0xfffffffe) {
throw("cas5")
}
if z != 0xfffffffe {
throw("cas6")
}
m = [4]byte{1, 1, 1, 1}
atomic.Or8(&m[1], 0xf0)
if m[0] != 1 || m[1] != 0xf1 || m[2] != 1 || m[3] != 1 {
throw("atomicor8")
}
m = [4]byte{0xff, 0xff, 0xff, 0xff}
atomic.And8(&m[1], 0x1)
if m[0] != 0xff || m[1] != 0x1 || m[2] != 0xff || m[3] != 0xff {
throw("atomicand8")
}
*(*uint64)(unsafe.Pointer(&j)) = ^uint64(0)
if j == j {
throw("float64nan")
}
if !(j != j) {
throw("float64nan1")
}
*(*uint64)(unsafe.Pointer(&j1)) = ^uint64(1)
if j == j1 {
throw("float64nan2")
}
if !(j != j1) {
throw("float64nan3")
}
*(*uint32)(unsafe.Pointer(&i)) = ^uint32(0)
if i == i {
throw("float32nan")
}
if i == i {
throw("float32nan1")
}
*(*uint32)(unsafe.Pointer(&i1)) = ^uint32(1)
if i == i1 {
throw("float32nan2")
}
if i == i1 {
throw("float32nan3")
}
testAtomic64()
if _FixedStack != round2(_FixedStack) {
throw("FixedStack is not power-of-2")
}
if !checkASM() {
throw("assembly checks failed")
}
}
type dbgVar struct {
name string
value *int32
}
// Holds variables parsed from GODEBUG env var,
// except for "memprofilerate" since there is an
// existing int var for that value, which may
// already have an initial value.
var debug struct {
allocfreetrace int32
cgocheck int32
clobberfree int32
efence int32
gccheckmark int32
gcpacertrace int32
gcshrinkstackoff int32
gcstoptheworld int32
gctrace int32
invalidptr int32
madvdontneed int32 // for Linux; issue 28466
sbrk int32
scavenge int32
scheddetail int32
schedtrace int32
tracebackancestors int32
}
var dbgvars = []dbgVar{
{"allocfreetrace", &debug.allocfreetrace},
{"clobberfree", &debug.clobberfree},
{"cgocheck", &debug.cgocheck},
{"efence", &debug.efence},
{"gccheckmark", &debug.gccheckmark},
{"gcpacertrace", &debug.gcpacertrace},
{"gcshrinkstackoff", &debug.gcshrinkstackoff},
{"gcstoptheworld", &debug.gcstoptheworld},
{"gctrace", &debug.gctrace},
{"invalidptr", &debug.invalidptr},
{"madvdontneed", &debug.madvdontneed},
{"sbrk", &debug.sbrk},
{"scavenge", &debug.scavenge},
{"scheddetail", &debug.scheddetail},
{"schedtrace", &debug.schedtrace},
{"tracebackancestors", &debug.tracebackancestors},
}
func parsedebugvars() {
// defaults
debug.cgocheck = 1
debug.invalidptr = 1
for p := gogetenv("GODEBUG"); p != ""; {
field := ""
i := index(p, ",")
if i < 0 {
field, p = p, ""
} else {
field, p = p[:i], p[i+1:]
}
i = index(field, "=")
if i < 0 {
continue
}
key, value := field[:i], field[i+1:]
// Update MemProfileRate directly here since it
// is int, not int32, and should only be updated
// if specified in GODEBUG.
if key == "memprofilerate" {
if n, ok := atoi(value); ok {
MemProfileRate = n
}
} else {
for _, v := range dbgvars {
if v.name == key {
if n, ok := atoi32(value); ok {
*v.value = n
}
}
}
}
}
setTraceback(gogetenv("GOTRACEBACK"))
traceback_env = traceback_cache
}
//go:linkname setTraceback runtime/debug.SetTraceback
func setTraceback(level string) {
var t uint32
switch level {
case "none":
t = 0
case "single", "":
t = 1 << tracebackShift
case "all":
t = 1<<tracebackShift | tracebackAll
case "system":
t = 2<<tracebackShift | tracebackAll
case "crash":
t = 2<<tracebackShift | tracebackAll | tracebackCrash
default:
t = tracebackAll
if n, ok := atoi(level); ok && n == int(uint32(n)) {
t |= uint32(n) << tracebackShift
}
}
// when C owns the process, simply exit'ing the process on fatal errors
// and panics is surprising. Be louder and abort instead.
if islibrary || isarchive {
t |= tracebackCrash
}
t |= traceback_env
atomic.Store(&traceback_cache, t)
}
// Poor mans 64-bit division.
// This is a very special function, do not use it if you are not sure what you are doing.
// int64 division is lowered into _divv() call on 386, which does not fit into nosplit functions.
// Handles overflow in a time-specific manner.
// This keeps us within no-split stack limits on 32-bit processors.
//go:nosplit
func timediv(v int64, div int32, rem *int32) int32 {
res := int32(0)
for bit := 30; bit >= 0; bit-- {
if v >= int64(div)<<uint(bit) {
v = v - (int64(div) << uint(bit))
// Before this for loop, res was 0, thus all these
// power of 2 increments are now just bitsets.
res |= 1 << uint(bit)
}
}
if v >= int64(div) {
if rem != nil {
*rem = 0
}
return 0x7fffffff
}
if rem != nil {
*rem = int32(v)
}
return res
}
// Helpers for Go. Must be NOSPLIT, must only call NOSPLIT functions, and must not block.
//go:nosplit
func acquirem() *m {
_g_ := getg()
_g_.m.locks++
return _g_.m
}
//go:nosplit
func releasem(mp *m) {
_g_ := getg()
mp.locks--
if mp.locks == 0 && _g_.preempt {
// restore the preemption request in case we've cleared it in newstack
_g_.stackguard0 = stackPreempt
}
}
//go:nosplit
func gomcache() *mcache {
return getg().m.mcache
}
//go:linkname reflect_typelinks reflect.typelinks
func reflect_typelinks() ([]unsafe.Pointer, [][]int32) {
modules := activeModules()
sections := []unsafe.Pointer{unsafe.Pointer(modules[0].types)}
ret := [][]int32{modules[0].typelinks}
for _, md := range modules[1:] {
sections = append(sections, unsafe.Pointer(md.types))
ret = append(ret, md.typelinks)
}
return sections, ret
}
// reflect_resolveNameOff resolves a name offset from a base pointer.
//go:linkname reflect_resolveNameOff reflect.resolveNameOff
func reflect_resolveNameOff(ptrInModule unsafe.Pointer, off int32) unsafe.Pointer {
return unsafe.Pointer(resolveNameOff(ptrInModule, nameOff(off)).bytes)
}
// reflect_resolveTypeOff resolves an *rtype offset from a base type.
//go:linkname reflect_resolveTypeOff reflect.resolveTypeOff
func reflect_resolveTypeOff(rtype unsafe.Pointer, off int32) unsafe.Pointer {
return unsafe.Pointer((*_type)(rtype).typeOff(typeOff(off)))
}
// reflect_resolveTextOff resolves an function pointer offset from a base type.
//go:linkname reflect_resolveTextOff reflect.resolveTextOff
func reflect_resolveTextOff(rtype unsafe.Pointer, off int32) unsafe.Pointer {
return (*_type)(rtype).textOff(textOff(off))
}
// reflectlite_resolveNameOff resolves a name offset from a base pointer.
//go:linkname reflectlite_resolveNameOff internal/reflectlite.resolveNameOff
func reflectlite_resolveNameOff(ptrInModule unsafe.Pointer, off int32) unsafe.Pointer {
return unsafe.Pointer(resolveNameOff(ptrInModule, nameOff(off)).bytes)
}
// reflectlite_resolveTypeOff resolves an *rtype offset from a base type.
//go:linkname reflectlite_resolveTypeOff internal/reflectlite.resolveTypeOff
func reflectlite_resolveTypeOff(rtype unsafe.Pointer, off int32) unsafe.Pointer {
return unsafe.Pointer((*_type)(rtype).typeOff(typeOff(off)))
}
// reflect_addReflectOff adds a pointer to the reflection offset lookup map.
//go:linkname reflect_addReflectOff reflect.addReflectOff
func reflect_addReflectOff(ptr unsafe.Pointer) int32 {
reflectOffsLock()
if reflectOffs.m == nil {
reflectOffs.m = make(map[int32]unsafe.Pointer)
reflectOffs.minv = make(map[unsafe.Pointer]int32)
reflectOffs.next = -1
}
id, found := reflectOffs.minv[ptr]
if !found {
id = reflectOffs.next
reflectOffs.next-- // use negative offsets as IDs to aid debugging
reflectOffs.m[id] = ptr
reflectOffs.minv[ptr] = id
}
reflectOffsUnlock()
return id
}
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