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      1 // Copyright 2011 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 cgo
      6 
      7 import "unsafe"
      8 
      9 // These utility functions are available to be called from code
     10 // compiled with gcc via crosscall2.
     11 
     12 // cgocallback is defined in runtime
     13 //go:linkname _runtime_cgocallback runtime.cgocallback
     14 func _runtime_cgocallback(unsafe.Pointer, unsafe.Pointer, uintptr, uintptr)
     15 
     16 // The declaration of crosscall2 is:
     17 //   void crosscall2(void (*fn)(void *, int), void *, int);
     18 //
     19 // We need to export the symbol crosscall2 in order to support
     20 // callbacks from shared libraries. This applies regardless of
     21 // linking mode.
     22 //
     23 // Compatibility note: crosscall2 actually takes four arguments, but
     24 // it works to call it with three arguments when calling _cgo_panic.
     25 // That is supported for backward compatibility.
     26 //go:cgo_export_static crosscall2
     27 //go:cgo_export_dynamic crosscall2
     28 
     29 // Panic. The argument is converted into a Go string.
     30 
     31 // Call like this in code compiled with gcc:
     32 //   struct { const char *p; } a;
     33 //   a.p = /* string to pass to panic */;
     34 //   crosscall2(_cgo_panic, &a, sizeof a);
     35 //   /* The function call will not return.  */
     36 
     37 //go:linkname _runtime_cgo_panic_internal runtime._cgo_panic_internal
     38 var _runtime_cgo_panic_internal byte
     39 
     40 //go:linkname _cgo_panic _cgo_panic
     41 //go:cgo_export_static _cgo_panic
     42 //go:cgo_export_dynamic _cgo_panic
     43 //go:nosplit
     44 //go:norace
     45 func _cgo_panic(a unsafe.Pointer, n int32) {
     46 	_runtime_cgocallback(unsafe.Pointer(&_runtime_cgo_panic_internal), a, uintptr(n), 0)
     47 }
     48 
     49 //go:cgo_import_static x_cgo_init
     50 //go:linkname x_cgo_init x_cgo_init
     51 //go:linkname _cgo_init _cgo_init
     52 var x_cgo_init byte
     53 var _cgo_init = &x_cgo_init
     54 
     55 //go:cgo_import_static x_cgo_thread_start
     56 //go:linkname x_cgo_thread_start x_cgo_thread_start
     57 //go:linkname _cgo_thread_start _cgo_thread_start
     58 var x_cgo_thread_start byte
     59 var _cgo_thread_start = &x_cgo_thread_start
     60 
     61 // Creates a new system thread without updating any Go state.
     62 //
     63 // This method is invoked during shared library loading to create a new OS
     64 // thread to perform the runtime initialization. This method is similar to
     65 // _cgo_sys_thread_start except that it doesn't update any Go state.
     66 
     67 //go:cgo_import_static x_cgo_sys_thread_create
     68 //go:linkname x_cgo_sys_thread_create x_cgo_sys_thread_create
     69 //go:linkname _cgo_sys_thread_create _cgo_sys_thread_create
     70 var x_cgo_sys_thread_create byte
     71 var _cgo_sys_thread_create = &x_cgo_sys_thread_create
     72 
     73 // Notifies that the runtime has been initialized.
     74 //
     75 // We currently block at every CGO entry point (via _cgo_wait_runtime_init_done)
     76 // to ensure that the runtime has been initialized before the CGO call is
     77 // executed. This is necessary for shared libraries where we kickoff runtime
     78 // initialization in a separate thread and return without waiting for this
     79 // thread to complete the init.
     80 
     81 //go:cgo_import_static x_cgo_notify_runtime_init_done
     82 //go:linkname x_cgo_notify_runtime_init_done x_cgo_notify_runtime_init_done
     83 //go:linkname _cgo_notify_runtime_init_done _cgo_notify_runtime_init_done
     84 var x_cgo_notify_runtime_init_done byte
     85 var _cgo_notify_runtime_init_done = &x_cgo_notify_runtime_init_done
     86 
     87 // Sets the traceback context function. See runtime.SetCgoTraceback.
     88 
     89 //go:cgo_import_static x_cgo_set_context_function
     90 //go:linkname x_cgo_set_context_function x_cgo_set_context_function
     91 //go:linkname _cgo_set_context_function _cgo_set_context_function
     92 var x_cgo_set_context_function byte
     93 var _cgo_set_context_function = &x_cgo_set_context_function
     94 
     95 //go:cgo_export_static _cgo_topofstack
     96 //go:cgo_export_dynamic _cgo_topofstack
     97