libgo/go/runtime/runtime.go

   1 // Copyright 2009 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 (
   8         "runtime/internal/atomic"
   9         _ "unsafe" // for go:linkname
  10 )
  11
  12 //go:generate go run wincallback.go
  13 //go:generate go run mkduff.go
  14 //go:generate go run mkfastlog2table.go
  15
  16 // For gccgo, while we still have C runtime code, use go:linkname to
  17 // rename some functions to themselves, so that the compiler will
  18 // export them.
  19 //
  20 //go:linkname tickspersecond runtime.tickspersecond
  21
  22 var ticks struct {
  23         lock mutex
  24         pad  uint32 // ensure 8-byte alignment of val on 386
  25         val  uint64
  26 }
  27
  28 // Note: Called by runtime/pprof in addition to runtime code.
  29 func tickspersecond() int64 {
  30         r := int64(atomic.Load64(&ticks.val))
  31         if r != 0 {
  32                 return r
  33         }
  34         lock(&ticks.lock)
  35         r = int64(ticks.val)
  36         if r == 0 {
  37                 t0 := nanotime()
  38                 c0 := cputicks()
  39                 usleep(100 * 1000)
  40                 t1 := nanotime()
  41                 c1 := cputicks()
  42                 if t1 == t0 {
  43                         t1++
  44                 }
  45                 r = (c1 - c0) * 1000 * 1000 * 1000 / (t1 - t0)
  46                 if r == 0 {
  47                         r++
  48                 }
  49                 atomic.Store64(&ticks.val, uint64(r))
  50         }
  51         unlock(&ticks.lock)
  52         return r
  53 }
  54
  55 var envs []string
  56 var argslice []string
  57
  58 //go:linkname syscall_runtime_envs syscall.runtime_envs
  59 func syscall_runtime_envs() []string { return append([]string{}, envs...) }
  60
  61 //go:linkname syscall_Getpagesize syscall.Getpagesize
  62 func syscall_Getpagesize() int { return int(physPageSize) }
  63
  64 //go:linkname os_runtime_args os.runtime_args
  65 func os_runtime_args() []string { return append([]string{}, argslice...) }
  66
  67 // Temporary, for the gccgo runtime code written in C.
  68 //go:linkname get_envs runtime_get_envs
  69 func get_envs() []string { return envs }
  70
  71 //go:linkname get_args runtime_get_args
  72 func get_args() []string { return argslice }