diff options
Diffstat (limited to 'lib/xray/xray_init.cc')
| -rw-r--r-- | lib/xray/xray_init.cc | 54 |
1 files changed, 39 insertions, 15 deletions
diff --git a/lib/xray/xray_init.cc b/lib/xray/xray_init.cc index 9d012e9a6..07f692431 100644 --- a/lib/xray/xray_init.cc +++ b/lib/xray/xray_init.cc @@ -12,7 +12,6 @@ // XRay initialisation logic. //===----------------------------------------------------------------------===// -#include <atomic> #include <fcntl.h> #include <strings.h> #include <unistd.h> @@ -26,9 +25,10 @@ extern "C" { void __xray_init(); extern const XRaySledEntry __start_xray_instr_map[] __attribute__((weak)); extern const XRaySledEntry __stop_xray_instr_map[] __attribute__((weak)); +extern const XRayFunctionSledIndex __start_xray_fn_idx[] __attribute__((weak)); +extern const XRayFunctionSledIndex __stop_xray_fn_idx[] __attribute__((weak)); } -using namespace __sanitizer; using namespace __xray; // When set to 'true' this means the XRay runtime has been initialised. We use @@ -38,33 +38,57 @@ using namespace __xray; // // FIXME: Support DSO instrumentation maps too. The current solution only works // for statically linked executables. -std::atomic<bool> XRayInitialized{false}; +__sanitizer::atomic_uint8_t XRayInitialized{0}; // This should always be updated before XRayInitialized is updated. -std::atomic<__xray::XRaySledMap> XRayInstrMap{}; +__sanitizer::SpinMutex XRayInstrMapMutex; +XRaySledMap XRayInstrMap; + +// Global flag to determine whether the flags have been initialized. +__sanitizer::atomic_uint8_t XRayFlagsInitialized{0}; + +// A mutex to allow only one thread to initialize the XRay data structures. +__sanitizer::SpinMutex XRayInitMutex; // __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(); + __sanitizer::SpinMutexLock Guard(&XRayInitMutex); + // Short-circuit if we've already initialized XRay before. + if (__sanitizer::atomic_load(&XRayInitialized, + __sanitizer::memory_order_acquire)) + return; + + if (!__sanitizer::atomic_load(&XRayFlagsInitialized, + __sanitizer::memory_order_acquire)) { + initializeFlags(); + __sanitizer::atomic_store(&XRayFlagsInitialized, true, + __sanitizer::memory_order_release); + } + if (__start_xray_instr_map == nullptr) { - Report("XRay instrumentation map missing. Not initializing XRay.\n"); + if (Verbosity()) + 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); + { + __sanitizer::SpinMutexLock Guard(&XRayInstrMapMutex); + XRayInstrMap.Sleds = __start_xray_instr_map; + XRayInstrMap.Entries = __stop_xray_instr_map - __start_xray_instr_map; + XRayInstrMap.SledsIndex = __start_xray_fn_idx; + XRayInstrMap.Functions = __stop_xray_fn_idx - __start_xray_fn_idx; + } + __sanitizer::atomic_store(&XRayInitialized, true, + __sanitizer::memory_order_release); +#ifndef XRAY_NO_PREINIT if (flags()->patch_premain) __xray_patch(); +#endif } +#ifndef XRAY_NO_PREINIT __attribute__((section(".preinit_array"), used)) void (*__local_xray_preinit)(void) = __xray_init; +#endif |