compiler-rt/lib/xray/xray_dso_init.cpp

   1 //===-- xray_init.cpp -------------------------------------------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file is a part of XRay, a dynamic runtime instrumentation system.
  10 //
  11 // XRay initialisation logic for DSOs.
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "sanitizer_common/sanitizer_atomic.h"
  15 #include "xray_defs.h"
  16 #include "xray_flags.h"
  17 #include "xray_interface_internal.h"
  18
  19 using namespace __sanitizer;
  20
  21 extern "C" {
  22 extern const XRaySledEntry __start_xray_instr_map[] __attribute__((weak))
  23 __attribute__((visibility("hidden")));
  24 extern const XRaySledEntry __stop_xray_instr_map[] __attribute__((weak))
  25 __attribute__((visibility("hidden")));
  26 extern const XRayFunctionSledIndex __start_xray_fn_idx[] __attribute__((weak))
  27 __attribute__((visibility("hidden")));
  28 extern const XRayFunctionSledIndex __stop_xray_fn_idx[] __attribute__((weak))
  29 __attribute__((visibility("hidden")));
  30
  31 #if SANITIZER_APPLE
  32 // HACK: This is a temporary workaround to make XRay build on
  33 // Darwin, but it will probably not work at runtime.
  34 extern const XRaySledEntry __start_xray_instr_map[] = {};
  35 extern const XRaySledEntry __stop_xray_instr_map[] = {};
  36 extern const XRayFunctionSledIndex __start_xray_fn_idx[] = {};
  37 extern const XRayFunctionSledIndex __stop_xray_fn_idx[] = {};
  38 #endif
  39 }
  40
  41 // Handler functions to call in the patched entry/exit sled.
  42 extern atomic_uintptr_t XRayPatchedFunction;
  43 extern atomic_uintptr_t XRayArgLogger;
  44 extern atomic_uintptr_t XRayPatchedCustomEvent;
  45 extern atomic_uintptr_t XRayPatchedTypedEvent;
  46
  47 static int __xray_object_id{-1};
  48
  49 // Note: .preinit_array initialization does not work for DSOs
  50 __attribute__((constructor(0))) static void
  51 __xray_init_dso() XRAY_NEVER_INSTRUMENT {
  52   // Register sleds in main XRay runtime.
  53   __xray_object_id =
  54       __xray_register_dso(__start_xray_instr_map, __stop_xray_instr_map,
  55                           __start_xray_fn_idx, __stop_xray_fn_idx, {});
  56 }
  57
  58 __attribute__((destructor(0))) static void
  59 __xray_finalize_dso() XRAY_NEVER_INSTRUMENT {
  60   // Inform the main runtime that this DSO is no longer used.
  61   __xray_deregister_dso(__xray_object_id);
  62 }