| // 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" |
| ) |
| |
| // For gccgo, while we still have C runtime code, use go:linkname to |
| // rename some functions to themselves, so that the compiler will |
| // export them. |
| // |
| //go:linkname gotraceback runtime.gotraceback |
| //go:linkname args runtime.args |
| //go:linkname goargs runtime.goargs |
| //go:linkname check runtime.check |
| //go:linkname goenvs_unix runtime.goenvs_unix |
| //go:linkname parsedebugvars runtime.parsedebugvars |
| //go:linkname timediv runtime.timediv |
| |
| // 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, k1 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") |
| } |
| |
| k = unsafe.Pointer(uintptr(0xfedcb123)) |
| if sys.PtrSize == 8 { |
| k = unsafe.Pointer(uintptr(k) << 10) |
| } |
| if casp(&k, nil, nil) { |
| throw("casp1") |
| } |
| k1 = add(k, 1) |
| if !casp(&k, k, k1) { |
| throw("casp2") |
| } |
| if k != k1 { |
| throw("casp3") |
| } |
| |
| 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 |
| efence int32 |
| gccheckmark int32 |
| gcpacertrace int32 |
| gcshrinkstackoff int32 |
| gcrescanstacks int32 |
| gcstoptheworld int32 |
| gctrace int32 |
| invalidptr int32 |
| sbrk int32 |
| scavenge int32 |
| scheddetail int32 |
| schedtrace int32 |
| } |
| |
| var dbgvars = []dbgVar{ |
| {"allocfreetrace", &debug.allocfreetrace}, |
| {"cgocheck", &debug.cgocheck}, |
| {"efence", &debug.efence}, |
| {"gccheckmark", &debug.gccheckmark}, |
| {"gcpacertrace", &debug.gcpacertrace}, |
| {"gcshrinkstackoff", &debug.gcshrinkstackoff}, |
| {"gcrescanstacks", &debug.gcrescanstacks}, |
| {"gcstoptheworld", &debug.gcstoptheworld}, |
| {"gctrace", &debug.gctrace}, |
| {"invalidptr", &debug.invalidptr}, |
| {"sbrk", &debug.sbrk}, |
| {"scavenge", &debug.scavenge}, |
| {"scheddetail", &debug.scheddetail}, |
| {"schedtrace", &debug.schedtrace}, |
| } |
| |
| func parsedebugvars() { |
| // defaults |
| debug.cgocheck = 1 |
| |
| // Unfortunately, because gccgo uses conservative stack scanning, |
| // we can not enable invalid pointer checking. It is possible for |
| // memory block M1 to point to M2, and for both to be dead. |
| // We release M2, causing the entire span to be released. |
| // Before we release M1, a stack pointer appears that point into it. |
| // This stack pointer is presumably dead, but causes M1 to be marked. |
| // We scan M1 and see the pointer to M2 on a released span. |
| // At that point, if debug.invalidptr is set, we crash. |
| // This is not a problem, assuming that M1 really is dead and |
| // the pointer we discovered to it will not be used. |
| // 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. |
| //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)) |
| 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 |
| } |
