github.com/reiver/go@v0.0.0-20150109200633-1d0c7792f172/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  // Declarations for runtime services implemented in C or assembly.
    10  
    11  const ptrSize = 4 << (^uintptr(0) >> 63) // unsafe.Sizeof(uintptr(0)) but an ideal const
    12  const regSize = 4 << (^uintreg(0) >> 63) // unsafe.Sizeof(uintreg(0)) but an ideal const
    13  
    14  // Should be a built-in for unsafe.Pointer?
    15  //go:nosplit
    16  func add(p unsafe.Pointer, x uintptr) unsafe.Pointer {
    17  	return unsafe.Pointer(uintptr(p) + x)
    18  }
    19  
    20  // n must be a power of 2
    21  func roundup(p unsafe.Pointer, n uintptr) unsafe.Pointer {
    22  	delta := -uintptr(p) & (n - 1)
    23  	return unsafe.Pointer(uintptr(p) + delta)
    24  }
    25  
    26  func getg() *g
    27  
    28  // mcall switches from the g to the g0 stack and invokes fn(g),
    29  // where g is the goroutine that made the call.
    30  // mcall saves g's current PC/SP in g->sched so that it can be restored later.
    31  // It is up to fn to arrange for that later execution, typically by recording
    32  // g in a data structure, causing something to call ready(g) later.
    33  // mcall returns to the original goroutine g later, when g has been rescheduled.
    34  // fn must not return at all; typically it ends by calling schedule, to let the m
    35  // run other goroutines.
    36  //
    37  // mcall can only be called from g stacks (not g0, not gsignal).
    38  //go:noescape
    39  func mcall(fn func(*g))
    40  
    41  // systemstack runs fn on a system stack.
    42  // If systemstack is called from the per-OS-thread (g0) stack, or
    43  // if systemstack is called from the signal handling (gsignal) stack,
    44  // systemstack calls fn directly and returns.
    45  // Otherwise, systemstack is being called from the limited stack
    46  // of an ordinary goroutine. In this case, systemstack switches
    47  // to the per-OS-thread stack, calls fn, and switches back.
    48  // It is common to use a func literal as the argument, in order
    49  // to share inputs and outputs with the code around the call
    50  // to system stack:
    51  //
    52  //	... set up y ...
    53  //	systemstack(func() {
    54  //		x = bigcall(y)
    55  //	})
    56  //	... use x ...
    57  //
    58  //go:noescape
    59  func systemstack(fn func())
    60  
    61  func badsystemstack() {
    62  	throw("systemstack called from unexpected goroutine")
    63  }
    64  
    65  // memclr clears n bytes starting at ptr.
    66  // in memclr_*.s
    67  //go:noescape
    68  func memclr(ptr unsafe.Pointer, n uintptr)
    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 memeq(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 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  func cgocallback_gofunc(fv *funcval, frame unsafe.Pointer, framesize uintptr)
   126  func goexit()
   127  
   128  //go:noescape
   129  func cas(ptr *uint32, old, new uint32) bool
   130  
   131  // NO go:noescape annotation; see atomic_pointer.go.
   132  func casp1(ptr *unsafe.Pointer, old, new unsafe.Pointer) bool
   133  
   134  func nop() // call to prevent inlining of function body
   135  
   136  //go:noescape
   137  func casuintptr(ptr *uintptr, old, new uintptr) bool
   138  
   139  //go:noescape
   140  func atomicstoreuintptr(ptr *uintptr, new uintptr)
   141  
   142  //go:noescape
   143  func atomicloaduintptr(ptr *uintptr) uintptr
   144  
   145  //go:noescape
   146  func atomicloaduint(ptr *uint) uint
   147  
   148  //go:noescape
   149  func setcallerpc(argp unsafe.Pointer, pc uintptr)
   150  
   151  // getcallerpc returns the program counter (PC) of its caller's caller.
   152  // getcallersp returns the stack pointer (SP) of its caller's caller.
   153  // For both, the argp must be a pointer to the caller's first function argument.
   154  // The implementation may or may not use argp, depending on
   155  // the architecture.
   156  //
   157  // For example:
   158  //
   159  //	func f(arg1, arg2, arg3 int) {
   160  //		pc := getcallerpc(unsafe.Pointer(&arg1))
   161  //		sp := getcallersp(unsafe.Pointer(&arg1))
   162  //	}
   163  //
   164  // These two lines find the PC and SP immediately following
   165  // the call to f (where f will return).
   166  //
   167  // The call to getcallerpc and getcallersp must be done in the
   168  // frame being asked about. It would not be correct for f to pass &arg1
   169  // to another function g and let g call getcallerpc/getcallersp.
   170  // The call inside g might return information about g's caller or
   171  // information about f's caller or complete garbage.
   172  //
   173  // The result of getcallersp is correct at the time of the return,
   174  // but it may be invalidated by any subsequent call to a function
   175  // that might relocate the stack in order to grow or shrink it.
   176  // A general rule is that the result of getcallersp should be used
   177  // immediately and can only be passed to nosplit functions.
   178  
   179  //go:noescape
   180  func getcallerpc(argp unsafe.Pointer) uintptr
   181  
   182  //go:noescape
   183  func getcallersp(argp unsafe.Pointer) uintptr
   184  
   185  //go:noescape
   186  func asmcgocall(fn, arg unsafe.Pointer)
   187  
   188  //go:noescape
   189  func asmcgocall_errno(fn, arg unsafe.Pointer) int32
   190  
   191  // argp used in Defer structs when there is no argp.
   192  const _NoArgs = ^uintptr(0)
   193  
   194  func morestack()
   195  func rt0_go()
   196  
   197  // return0 is a stub used to return 0 from deferproc.
   198  // It is called at the very end of deferproc to signal
   199  // the calling Go function that it should not jump
   200  // to deferreturn.
   201  // in asm_*.s
   202  func return0()
   203  
   204  //go:linkname time_now time.now
   205  func time_now() (sec int64, nsec int32)
   206  
   207  // in asm_*.s
   208  // not called directly; definitions here supply type information for traceback.
   209  func call16(fn, arg unsafe.Pointer, n, retoffset uint32)
   210  func call32(fn, arg unsafe.Pointer, n, retoffset uint32)
   211  func call64(fn, arg unsafe.Pointer, n, retoffset uint32)
   212  func call128(fn, arg unsafe.Pointer, n, retoffset uint32)
   213  func call256(fn, arg unsafe.Pointer, n, retoffset uint32)
   214  func call512(fn, arg unsafe.Pointer, n, retoffset uint32)
   215  func call1024(fn, arg unsafe.Pointer, n, retoffset uint32)
   216  func call2048(fn, arg unsafe.Pointer, n, retoffset uint32)
   217  func call4096(fn, arg unsafe.Pointer, n, retoffset uint32)
   218  func call8192(fn, arg unsafe.Pointer, n, retoffset uint32)
   219  func call16384(fn, arg unsafe.Pointer, n, retoffset uint32)
   220  func call32768(fn, arg unsafe.Pointer, n, retoffset uint32)
   221  func call65536(fn, arg unsafe.Pointer, n, retoffset uint32)
   222  func call131072(fn, arg unsafe.Pointer, n, retoffset uint32)
   223  func call262144(fn, arg unsafe.Pointer, n, retoffset uint32)
   224  func call524288(fn, arg unsafe.Pointer, n, retoffset uint32)
   225  func call1048576(fn, arg unsafe.Pointer, n, retoffset uint32)
   226  func call2097152(fn, arg unsafe.Pointer, n, retoffset uint32)
   227  func call4194304(fn, arg unsafe.Pointer, n, retoffset uint32)
   228  func call8388608(fn, arg unsafe.Pointer, n, retoffset uint32)
   229  func call16777216(fn, arg unsafe.Pointer, n, retoffset uint32)
   230  func call33554432(fn, arg unsafe.Pointer, n, retoffset uint32)
   231  func call67108864(fn, arg unsafe.Pointer, n, retoffset uint32)
   232  func call134217728(fn, arg unsafe.Pointer, n, retoffset uint32)
   233  func call268435456(fn, arg unsafe.Pointer, n, retoffset uint32)
   234  func call536870912(fn, arg unsafe.Pointer, n, retoffset uint32)
   235  func call1073741824(fn, arg unsafe.Pointer, n, retoffset uint32)
   236  
   237  func systemstack_switch()
   238  
   239  func prefetcht0(addr uintptr)
   240  func prefetcht1(addr uintptr)
   241  func prefetcht2(addr uintptr)
   242  func prefetchnta(addr uintptr)