github.com/brownsys/tracing-framework-go@v0.0.0-20161210174012-0542a62412fe/go/darwin_amd64/src/runtime/stubs.go (about) 1 // Copyright 2014 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 package runtime 6 7 import "unsafe" 8 9 // Should be a built-in for unsafe.Pointer? 10 //go:nosplit 11 func add(p unsafe.Pointer, x uintptr) unsafe.Pointer { 12 return unsafe.Pointer(uintptr(p) + x) 13 } 14 15 // getg returns the pointer to the current g. 16 // The compiler rewrites calls to this function into instructions 17 // that fetch the g directly (from TLS or from the dedicated register). 18 func getg() *g 19 20 // mcall switches from the g to the g0 stack and invokes fn(g), 21 // where g is the goroutine that made the call. 22 // mcall saves g's current PC/SP in g->sched so that it can be restored later. 23 // It is up to fn to arrange for that later execution, typically by recording 24 // g in a data structure, causing something to call ready(g) later. 25 // mcall returns to the original goroutine g later, when g has been rescheduled. 26 // fn must not return at all; typically it ends by calling schedule, to let the m 27 // run other goroutines. 28 // 29 // mcall can only be called from g stacks (not g0, not gsignal). 30 // 31 // This must NOT be go:noescape: if fn is a stack-allocated closure, 32 // fn puts g on a run queue, and g executes before fn returns, the 33 // closure will be invalidated while it is still executing. 34 func mcall(fn func(*g)) 35 36 // systemstack runs fn on a system stack. 37 // If systemstack is called from the per-OS-thread (g0) stack, or 38 // if systemstack is called from the signal handling (gsignal) stack, 39 // systemstack calls fn directly and returns. 40 // Otherwise, systemstack is being called from the limited stack 41 // of an ordinary goroutine. In this case, systemstack switches 42 // to the per-OS-thread stack, calls fn, and switches back. 43 // It is common to use a func literal as the argument, in order 44 // to share inputs and outputs with the code around the call 45 // to system stack: 46 // 47 // ... set up y ... 48 // systemstack(func() { 49 // x = bigcall(y) 50 // }) 51 // ... use x ... 52 // 53 //go:noescape 54 func systemstack(fn func()) 55 56 func badsystemstack() { 57 throw("systemstack called from unexpected goroutine") 58 } 59 60 // memclr clears n bytes starting at ptr. 61 // in memclr_*.s 62 //go:noescape 63 func memclr(ptr unsafe.Pointer, n uintptr) 64 65 //go:linkname reflect_memclr reflect.memclr 66 func reflect_memclr(ptr unsafe.Pointer, n uintptr) { 67 memclr(ptr, n) 68 } 69 70 // memmove copies n bytes from "from" to "to". 71 // in memmove_*.s 72 //go:noescape 73 func memmove(to, from unsafe.Pointer, n uintptr) 74 75 //go:linkname reflect_memmove reflect.memmove 76 func reflect_memmove(to, from unsafe.Pointer, n uintptr) { 77 memmove(to, from, n) 78 } 79 80 // exported value for testing 81 var hashLoad = loadFactor 82 83 // in asm_*.s 84 func fastrand1() uint32 85 86 // in asm_*.s 87 //go:noescape 88 func memequal(a, b unsafe.Pointer, size uintptr) bool 89 90 // noescape hides a pointer from escape analysis. noescape is 91 // the identity function but escape analysis doesn't think the 92 // output depends on the input. noescape is inlined and currently 93 // compiles down to a single xor instruction. 94 // USE CAREFULLY! 95 //go:nosplit 96 func noescape(p unsafe.Pointer) unsafe.Pointer { 97 x := uintptr(p) 98 return unsafe.Pointer(x ^ 0) 99 } 100 101 func cgocallback(fn, frame unsafe.Pointer, framesize, ctxt uintptr) 102 func gogo(buf *gobuf) 103 func gosave(buf *gobuf) 104 func mincore(addr unsafe.Pointer, n uintptr, dst *byte) int32 105 106 //go:noescape 107 func jmpdefer(fv *funcval, argp uintptr) 108 func exit1(code int32) 109 func asminit() 110 func setg(gg *g) 111 func breakpoint() 112 113 // reflectcall calls fn with a copy of the n argument bytes pointed at by arg. 114 // After fn returns, reflectcall copies n-retoffset result bytes 115 // back into arg+retoffset before returning. If copying result bytes back, 116 // the caller should pass the argument frame type as argtype, so that 117 // call can execute appropriate write barriers during the copy. 118 // Package reflect passes a frame type. In package runtime, there is only 119 // one call that copies results back, in cgocallbackg1, and it does NOT pass a 120 // frame type, meaning there are no write barriers invoked. See that call 121 // site for justification. 122 func reflectcall(argtype *_type, fn, arg unsafe.Pointer, argsize uint32, retoffset uint32) 123 124 func procyield(cycles uint32) 125 126 type neverCallThisFunction struct{} 127 128 // goexit is the return stub at the top of every goroutine call stack. 129 // Each goroutine stack is constructed as if goexit called the 130 // goroutine's entry point function, so that when the entry point 131 // function returns, it will return to goexit, which will call goexit1 132 // to perform the actual exit. 133 // 134 // This function must never be called directly. Call goexit1 instead. 135 // gentraceback assumes that goexit terminates the stack. A direct 136 // call on the stack will cause gentraceback to stop walking the stack 137 // prematurely and if there are leftover stack barriers it may panic. 138 func goexit(neverCallThisFunction) 139 140 // Not all cgocallback_gofunc frames are actually cgocallback_gofunc, 141 // so not all have these arguments. Mark them uintptr so that the GC 142 // does not misinterpret memory when the arguments are not present. 143 // cgocallback_gofunc is not called from go, only from cgocallback, 144 // so the arguments will be found via cgocallback's pointer-declared arguments. 145 // See the assembly implementations for more details. 146 func cgocallback_gofunc(fv uintptr, frame uintptr, framesize, ctxt uintptr) 147 148 // publicationBarrier performs a store/store barrier (a "publication" 149 // or "export" barrier). Some form of synchronization is required 150 // between initializing an object and making that object accessible to 151 // another processor. Without synchronization, the initialization 152 // writes and the "publication" write may be reordered, allowing the 153 // other processor to follow the pointer and observe an uninitialized 154 // object. In general, higher-level synchronization should be used, 155 // such as locking or an atomic pointer write. publicationBarrier is 156 // for when those aren't an option, such as in the implementation of 157 // the memory manager. 158 // 159 // There's no corresponding barrier for the read side because the read 160 // side naturally has a data dependency order. All architectures that 161 // Go supports or seems likely to ever support automatically enforce 162 // data dependency ordering. 163 func publicationBarrier() 164 165 //go:noescape 166 func setcallerpc(argp unsafe.Pointer, pc uintptr) 167 168 // getcallerpc returns the program counter (PC) of its caller's caller. 169 // getcallersp returns the stack pointer (SP) of its caller's caller. 170 // For both, the argp must be a pointer to the caller's first function argument. 171 // The implementation may or may not use argp, depending on 172 // the architecture. 173 // 174 // For example: 175 // 176 // func f(arg1, arg2, arg3 int) { 177 // pc := getcallerpc(unsafe.Pointer(&arg1)) 178 // sp := getcallersp(unsafe.Pointer(&arg1)) 179 // } 180 // 181 // These two lines find the PC and SP immediately following 182 // the call to f (where f will return). 183 // 184 // The call to getcallerpc and getcallersp must be done in the 185 // frame being asked about. It would not be correct for f to pass &arg1 186 // to another function g and let g call getcallerpc/getcallersp. 187 // The call inside g might return information about g's caller or 188 // information about f's caller or complete garbage. 189 // 190 // The result of getcallersp is correct at the time of the return, 191 // but it may be invalidated by any subsequent call to a function 192 // that might relocate the stack in order to grow or shrink it. 193 // A general rule is that the result of getcallersp should be used 194 // immediately and can only be passed to nosplit functions. 195 196 //go:noescape 197 func getcallerpc(argp unsafe.Pointer) uintptr 198 199 //go:noescape 200 func getcallersp(argp unsafe.Pointer) uintptr 201 202 //go:noescape 203 func asmcgocall(fn, arg unsafe.Pointer) int32 204 205 // argp used in Defer structs when there is no argp. 206 const _NoArgs = ^uintptr(0) 207 208 func morestack() 209 func rt0_go() 210 211 // stackBarrier records that the stack has been unwound past a certain 212 // point. It is installed over a return PC on the stack. It must 213 // retrieve the original return PC from g.stkbuf, increment 214 // g.stkbufPos to record that the barrier was hit, and jump to the 215 // original return PC. 216 func stackBarrier() 217 218 // return0 is a stub used to return 0 from deferproc. 219 // It is called at the very end of deferproc to signal 220 // the calling Go function that it should not jump 221 // to deferreturn. 222 // in asm_*.s 223 func return0() 224 225 //go:linkname time_now time.now 226 func time_now() (sec int64, nsec int32) 227 228 // in asm_*.s 229 // not called directly; definitions here supply type information for traceback. 230 func call32(fn, arg unsafe.Pointer, n, retoffset uint32) 231 func call64(fn, arg unsafe.Pointer, n, retoffset uint32) 232 func call128(fn, arg unsafe.Pointer, n, retoffset uint32) 233 func call256(fn, arg unsafe.Pointer, n, retoffset uint32) 234 func call512(fn, arg unsafe.Pointer, n, retoffset uint32) 235 func call1024(fn, arg unsafe.Pointer, n, retoffset uint32) 236 func call2048(fn, arg unsafe.Pointer, n, retoffset uint32) 237 func call4096(fn, arg unsafe.Pointer, n, retoffset uint32) 238 func call8192(fn, arg unsafe.Pointer, n, retoffset uint32) 239 func call16384(fn, arg unsafe.Pointer, n, retoffset uint32) 240 func call32768(fn, arg unsafe.Pointer, n, retoffset uint32) 241 func call65536(fn, arg unsafe.Pointer, n, retoffset uint32) 242 func call131072(fn, arg unsafe.Pointer, n, retoffset uint32) 243 func call262144(fn, arg unsafe.Pointer, n, retoffset uint32) 244 func call524288(fn, arg unsafe.Pointer, n, retoffset uint32) 245 func call1048576(fn, arg unsafe.Pointer, n, retoffset uint32) 246 func call2097152(fn, arg unsafe.Pointer, n, retoffset uint32) 247 func call4194304(fn, arg unsafe.Pointer, n, retoffset uint32) 248 func call8388608(fn, arg unsafe.Pointer, n, retoffset uint32) 249 func call16777216(fn, arg unsafe.Pointer, n, retoffset uint32) 250 func call33554432(fn, arg unsafe.Pointer, n, retoffset uint32) 251 func call67108864(fn, arg unsafe.Pointer, n, retoffset uint32) 252 func call134217728(fn, arg unsafe.Pointer, n, retoffset uint32) 253 func call268435456(fn, arg unsafe.Pointer, n, retoffset uint32) 254 func call536870912(fn, arg unsafe.Pointer, n, retoffset uint32) 255 func call1073741824(fn, arg unsafe.Pointer, n, retoffset uint32) 256 257 func systemstack_switch() 258 259 func prefetcht0(addr uintptr) 260 func prefetcht1(addr uintptr) 261 func prefetcht2(addr uintptr) 262 func prefetchnta(addr uintptr) 263 264 func unixnanotime() int64 { 265 sec, nsec := time_now() 266 return sec*1e9 + int64(nsec) 267 } 268 269 // round n up to a multiple of a. a must be a power of 2. 270 func round(n, a uintptr) uintptr { 271 return (n + a - 1) &^ (a - 1) 272 } 273 274 // checkASM returns whether assembly runtime checks have passed. 275 func checkASM() bool