github.com/shijuvar/go@v0.0.0-20141209052335-e8f13700b70c/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  	gothrow("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 unsafe.Pointer, from unsafe.Pointer, n uintptr)
    74  
    75  // exported value for testing
    76  var hashLoad = loadFactor
    77  
    78  // in asm_*.s
    79  func fastrand1() uint32
    80  
    81  // in asm_*.s
    82  //go:noescape
    83  func memeq(a, b unsafe.Pointer, size uintptr) bool
    84  
    85  // noescape hides a pointer from escape analysis.  noescape is
    86  // the identity function but escape analysis doesn't think the
    87  // output depends on the input.  noescape is inlined and currently
    88  // compiles down to a single xor instruction.
    89  // USE CAREFULLY!
    90  //go:nosplit
    91  func noescape(p unsafe.Pointer) unsafe.Pointer {
    92  	x := uintptr(p)
    93  	return unsafe.Pointer(x ^ 0)
    94  }
    95  
    96  func cgocallback(fn, frame unsafe.Pointer, framesize uintptr)
    97  func gogo(buf *gobuf)
    98  func gosave(buf *gobuf)
    99  func mincore(addr unsafe.Pointer, n uintptr, dst *byte) int32
   100  
   101  //go:noescape
   102  func jmpdefer(fv *funcval, argp uintptr)
   103  func exit1(code int32)
   104  func asminit()
   105  func setg(gg *g)
   106  func breakpoint()
   107  
   108  func reflectcall(fn, arg unsafe.Pointer, n uint32, retoffset uint32)
   109  func procyield(cycles uint32)
   110  func cgocallback_gofunc(fv *funcval, frame unsafe.Pointer, framesize uintptr)
   111  func goexit()
   112  
   113  //go:noescape
   114  func cas(ptr *uint32, old, new uint32) bool
   115  
   116  // casp cannot have a go:noescape annotation, because
   117  // while ptr and old do not escape, new does. If new is marked as
   118  // not escaping, the compiler will make incorrect escape analysis
   119  // decisions about the value being xchg'ed.
   120  // Instead, make casp a wrapper around the actual atomic.
   121  // When calling the wrapper we mark ptr as noescape explicitly.
   122  
   123  //go:nosplit
   124  func casp(ptr *unsafe.Pointer, old, new unsafe.Pointer) bool {
   125  	return casp1((*unsafe.Pointer)(noescape(unsafe.Pointer(ptr))), noescape(old), new)
   126  }
   127  
   128  func casp1(ptr *unsafe.Pointer, old, new unsafe.Pointer) bool
   129  
   130  func nop() // call to prevent inlining of function body
   131  
   132  //go:noescape
   133  func casuintptr(ptr *uintptr, old, new uintptr) bool
   134  
   135  //go:noescape
   136  func atomicstoreuintptr(ptr *uintptr, new uintptr)
   137  
   138  //go:noescape
   139  func atomicloaduintptr(ptr *uintptr) uintptr
   140  
   141  //go:noescape
   142  func atomicloaduint(ptr *uint) uint
   143  
   144  //go:noescape
   145  func setcallerpc(argp unsafe.Pointer, pc uintptr)
   146  
   147  // getcallerpc returns the program counter (PC) of its caller's caller.
   148  // getcallersp returns the stack pointer (SP) of its caller's caller.
   149  // For both, the argp must be a pointer to the caller's first function argument.
   150  // The implementation may or may not use argp, depending on
   151  // the architecture.
   152  //
   153  // For example:
   154  //
   155  //	func f(arg1, arg2, arg3 int) {
   156  //		pc := getcallerpc(unsafe.Pointer(&arg1))
   157  //		sp := getcallersp(unsafe.Pointer(&arg1))
   158  //	}
   159  //
   160  // These two lines find the PC and SP immediately following
   161  // the call to f (where f will return).
   162  //
   163  // The call to getcallerpc and getcallersp must be done in the
   164  // frame being asked about. It would not be correct for f to pass &arg1
   165  // to another function g and let g call getcallerpc/getcallersp.
   166  // The call inside g might return information about g's caller or
   167  // information about f's caller or complete garbage.
   168  //
   169  // The result of getcallersp is correct at the time of the return,
   170  // but it may be invalidated by any subsequent call to a function
   171  // that might relocate the stack in order to grow or shrink it.
   172  // A general rule is that the result of getcallersp should be used
   173  // immediately and can only be passed to nosplit functions.
   174  
   175  //go:noescape
   176  func getcallerpc(argp unsafe.Pointer) uintptr
   177  
   178  //go:noescape
   179  func getcallersp(argp unsafe.Pointer) uintptr
   180  
   181  //go:noescape
   182  func asmcgocall(fn, arg unsafe.Pointer)
   183  
   184  //go:noescape
   185  func asmcgocall_errno(fn, arg unsafe.Pointer) int32
   186  
   187  // argp used in Defer structs when there is no argp.
   188  const _NoArgs = ^uintptr(0)
   189  
   190  func morestack()
   191  func rt0_go()
   192  
   193  // return0 is a stub used to return 0 from deferproc.
   194  // It is called at the very end of deferproc to signal
   195  // the calling Go function that it should not jump
   196  // to deferreturn.
   197  // in asm_*.s
   198  func return0()
   199  
   200  // thunk to call time.now.
   201  func timenow() (sec int64, nsec int32)
   202  
   203  // in asm_*.s
   204  // not called directly; definitions here supply type information for traceback.
   205  func call16(fn, arg unsafe.Pointer, n, retoffset uint32)
   206  func call32(fn, arg unsafe.Pointer, n, retoffset uint32)
   207  func call64(fn, arg unsafe.Pointer, n, retoffset uint32)
   208  func call128(fn, arg unsafe.Pointer, n, retoffset uint32)
   209  func call256(fn, arg unsafe.Pointer, n, retoffset uint32)
   210  func call512(fn, arg unsafe.Pointer, n, retoffset uint32)
   211  func call1024(fn, arg unsafe.Pointer, n, retoffset uint32)
   212  func call2048(fn, arg unsafe.Pointer, n, retoffset uint32)
   213  func call4096(fn, arg unsafe.Pointer, n, retoffset uint32)
   214  func call8192(fn, arg unsafe.Pointer, n, retoffset uint32)
   215  func call16384(fn, arg unsafe.Pointer, n, retoffset uint32)
   216  func call32768(fn, arg unsafe.Pointer, n, retoffset uint32)
   217  func call65536(fn, arg unsafe.Pointer, n, retoffset uint32)
   218  func call131072(fn, arg unsafe.Pointer, n, retoffset uint32)
   219  func call262144(fn, arg unsafe.Pointer, n, retoffset uint32)
   220  func call524288(fn, arg unsafe.Pointer, n, retoffset uint32)
   221  func call1048576(fn, arg unsafe.Pointer, n, retoffset uint32)
   222  func call2097152(fn, arg unsafe.Pointer, n, retoffset uint32)
   223  func call4194304(fn, arg unsafe.Pointer, n, retoffset uint32)
   224  func call8388608(fn, arg unsafe.Pointer, n, retoffset uint32)
   225  func call16777216(fn, arg unsafe.Pointer, n, retoffset uint32)
   226  func call33554432(fn, arg unsafe.Pointer, n, retoffset uint32)
   227  func call67108864(fn, arg unsafe.Pointer, n, retoffset uint32)
   228  func call134217728(fn, arg unsafe.Pointer, n, retoffset uint32)
   229  func call268435456(fn, arg unsafe.Pointer, n, retoffset uint32)
   230  func call536870912(fn, arg unsafe.Pointer, n, retoffset uint32)
   231  func call1073741824(fn, arg unsafe.Pointer, n, retoffset uint32)
   232  
   233  func systemstack_switch()
   234  
   235  func prefetcht0(addr uintptr)
   236  func prefetcht1(addr uintptr)
   237  func prefetcht2(addr uintptr)
   238  func prefetchnta(addr uintptr)