| //===-- xray_init.cc --------------------------------------------*- C++ -*-===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file is a part of XRay, a dynamic runtime instrumentation system. |
| // |
| // XRay initialisation logic. |
| //===----------------------------------------------------------------------===// |
| |
| #include <atomic> |
| #include <fcntl.h> |
| #include <strings.h> |
| #include <unistd.h> |
| |
| #include "sanitizer_common/sanitizer_common.h" |
| #include "xray_defs.h" |
| #include "xray_flags.h" |
| #include "xray_interface_internal.h" |
| |
| extern "C" { |
| void __xray_init(); |
| extern const XRaySledEntry __start_xray_instr_map[] __attribute__((weak)); |
| extern const XRaySledEntry __stop_xray_instr_map[] __attribute__((weak)); |
| } |
| |
| using namespace __sanitizer; |
| using namespace __xray; |
| |
| // When set to 'true' this means the XRay runtime has been initialised. We use |
| // the weak symbols defined above (__start_xray_inst_map and |
| // __stop_xray_instr_map) to initialise the instrumentation map that XRay uses |
| // for runtime patching/unpatching of instrumentation points. |
| // |
| // FIXME: Support DSO instrumentation maps too. The current solution only works |
| // for statically linked executables. |
| std::atomic<bool> XRayInitialized{false}; |
| |
| // This should always be updated before XRayInitialized is updated. |
| std::atomic<__xray::XRaySledMap> XRayInstrMap{}; |
| |
| // __xray_init() will do the actual loading of the current process' memory map |
| // and then proceed to look for the .xray_instr_map section/segment. |
| void __xray_init() XRAY_NEVER_INSTRUMENT { |
| InitializeFlags(); |
| if (__start_xray_instr_map == nullptr) { |
| Report("XRay instrumentation map missing. Not initializing XRay.\n"); |
| return; |
| } |
| |
| // Now initialize the XRayInstrMap global struct with the address of the |
| // entries, reinterpreted as an array of XRaySledEntry objects. We use the |
| // virtual pointer we have from the section to provide us the correct |
| // information. |
| __xray::XRaySledMap SledMap{}; |
| SledMap.Sleds = __start_xray_instr_map; |
| SledMap.Entries = __stop_xray_instr_map - __start_xray_instr_map; |
| XRayInstrMap.store(SledMap, std::memory_order_release); |
| XRayInitialized.store(true, std::memory_order_release); |
| |
| if (flags()->patch_premain) |
| __xray_patch(); |
| } |
| |
| __attribute__((section(".preinit_array"), |
| used)) void (*__local_xray_preinit)(void) = __xray_init; |