1 files changed, 515 insertions, 0 deletions
diff --git a/lib/xray/xray_basic_logging.cpp b/lib/xray/xray_basic_logging.cpp
new file mode 100644
index 000000000000..6e8e93131451
--- /dev/null
+++ b/lib/xray/xray_basic_logging.cpp
@@ -0,0 +1,515 @@
+//===-- xray_basic_logging.cpp ----------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is a part of XRay, a dynamic runtime instrumentation system.
+//
+// Implementation of a simple in-memory log of XRay events. This defines a
+// logging function that's compatible with the XRay handler interface, and
+// routines for exporting data to files.
+//
+//===----------------------------------------------------------------------===//
+
+#include <errno.h>
+#include <fcntl.h>
+#include <pthread.h>
+#include <sys/stat.h>
+#if SANITIZER_FREEBSD || SANITIZER_NETBSD || SANITIZER_OPENBSD || SANITIZER_MAC
+#include <sys/syscall.h>
+#endif
+#include <sys/types.h>
+#include <time.h>
+#include <unistd.h>
+
+#include "sanitizer_common/sanitizer_allocator_internal.h"
+#include "sanitizer_common/sanitizer_libc.h"
+#include "xray/xray_records.h"
+#include "xray_recursion_guard.h"
+#include "xray_basic_flags.h"
+#include "xray_basic_logging.h"
+#include "xray_defs.h"
+#include "xray_flags.h"
+#include "xray_interface_internal.h"
+#include "xray_tsc.h"
+#include "xray_utils.h"
+
+namespace __xray {
+
+static SpinMutex LogMutex;
+
+namespace {
+// We use elements of this type to record the entry TSC of every function ID we
+// see as we're tracing a particular thread's execution.
+struct alignas(16) StackEntry {
+  int32_t FuncId;
+  uint16_t Type;
+  uint8_t CPU;
+  uint8_t Padding;
+  uint64_t TSC;
+};
+
+static_assert(sizeof(StackEntry) == 16, "Wrong size for StackEntry");
+
+struct XRAY_TLS_ALIGNAS(64) ThreadLocalData {
+  void *InMemoryBuffer = nullptr;
+  size_t BufferSize = 0;
+  size_t BufferOffset = 0;
+  void *ShadowStack = nullptr;
+  size_t StackSize = 0;
+  size_t StackEntries = 0;
+  __xray::LogWriter *LogWriter = nullptr;
+};
+
+struct BasicLoggingOptions {
+  int DurationFilterMicros = 0;
+  size_t MaxStackDepth = 0;
+  size_t ThreadBufferSize = 0;
+};
+} // namespace
+
+static pthread_key_t PThreadKey;
+
+static atomic_uint8_t BasicInitialized{0};
+
+struct BasicLoggingOptions GlobalOptions;
+
+thread_local atomic_uint8_t Guard{0};
+
+static atomic_uint8_t UseRealTSC{0};
+static atomic_uint64_t ThresholdTicks{0};
+static atomic_uint64_t TicksPerSec{0};
+static atomic_uint64_t CycleFrequency{NanosecondsPerSecond};
+
+static LogWriter *getLog() XRAY_NEVER_INSTRUMENT {
+  LogWriter* LW = LogWriter::Open();
+  if (LW == nullptr)
+    return LW;
+
+  static pthread_once_t DetectOnce = PTHREAD_ONCE_INIT;
+  pthread_once(&DetectOnce, +[] {
+    if (atomic_load(&UseRealTSC, memory_order_acquire))
+      atomic_store(&CycleFrequency, getTSCFrequency(), memory_order_release);
+  });
+
+  // Since we're here, we get to write the header. We set it up so that the
+  // header will only be written once, at the start, and let the threads
+  // logging do writes which just append.
+  XRayFileHeader Header;
+  // Version 2 includes tail exit records.
+  // Version 3 includes pid inside records.
+  Header.Version = 3;
+  Header.Type = FileTypes::NAIVE_LOG;
+  Header.CycleFrequency = atomic_load(&CycleFrequency, memory_order_acquire);
+
+  // FIXME: Actually check whether we have 'constant_tsc' and 'nonstop_tsc'
+  // before setting the values in the header.
+  Header.ConstantTSC = 1;
+  Header.NonstopTSC = 1;
+  LW->WriteAll(reinterpret_cast<char *>(&Header),
+               reinterpret_cast<char *>(&Header) + sizeof(Header));
+  return LW;
+}
+
+static LogWriter *getGlobalLog() XRAY_NEVER_INSTRUMENT {
+  static pthread_once_t OnceInit = PTHREAD_ONCE_INIT;
+  static LogWriter *LW = nullptr;
+  pthread_once(&OnceInit, +[] { LW = getLog(); });
+  return LW;
+}
+
+static ThreadLocalData &getThreadLocalData() XRAY_NEVER_INSTRUMENT {
+  thread_local ThreadLocalData TLD;
+  thread_local bool UNUSED TOnce = [] {
+    if (GlobalOptions.ThreadBufferSize == 0) {
+      if (Verbosity())
+        Report("Not initializing TLD since ThreadBufferSize == 0.\n");
+      return false;
+    }
+    pthread_setspecific(PThreadKey, &TLD);
+    TLD.LogWriter = getGlobalLog();
+    TLD.InMemoryBuffer = reinterpret_cast<XRayRecord *>(
+        InternalAlloc(sizeof(XRayRecord) * GlobalOptions.ThreadBufferSize,
+                      nullptr, alignof(XRayRecord)));
+    TLD.BufferSize = GlobalOptions.ThreadBufferSize;
+    TLD.BufferOffset = 0;
+    if (GlobalOptions.MaxStackDepth == 0) {
+      if (Verbosity())
+        Report("Not initializing the ShadowStack since MaxStackDepth == 0.\n");
+      TLD.StackSize = 0;
+      TLD.StackEntries = 0;
+      TLD.ShadowStack = nullptr;
+      return false;
+    }
+    TLD.ShadowStack = reinterpret_cast<StackEntry *>(
+        InternalAlloc(sizeof(StackEntry) * GlobalOptions.MaxStackDepth, nullptr,
+                      alignof(StackEntry)));
+    TLD.StackSize = GlobalOptions.MaxStackDepth;
+    TLD.StackEntries = 0;
+    return false;
+  }();
+  return TLD;
+}
+
+template <class RDTSC>
+void InMemoryRawLog(int32_t FuncId, XRayEntryType Type,
+                    RDTSC ReadTSC) XRAY_NEVER_INSTRUMENT {
+  auto &TLD = getThreadLocalData();
+  LogWriter *LW = getGlobalLog();
+  if (LW == nullptr)
+    return;
+
+  // Use a simple recursion guard, to handle cases where we're already logging
+  // and for one reason or another, this function gets called again in the same
+  // thread.
+  RecursionGuard G(Guard);
+  if (!G)
+    return;
+
+  uint8_t CPU = 0;
+  uint64_t TSC = ReadTSC(CPU);
+
+  switch (Type) {
+  case XRayEntryType::ENTRY:
+  case XRayEntryType::LOG_ARGS_ENTRY: {
+    // Short circuit if we've reached the maximum depth of the stack.
+    if (TLD.StackEntries++ >= TLD.StackSize)
+      return;
+
+    // When we encounter an entry event, we keep track of the TSC and the CPU,
+    // and put it in the stack.
+    StackEntry E;
+    E.FuncId = FuncId;
+    E.CPU = CPU;
+    E.Type = Type;
+    E.TSC = TSC;
+    auto StackEntryPtr = static_cast<char *>(TLD.ShadowStack) +
+                         (sizeof(StackEntry) * (TLD.StackEntries - 1));
+    internal_memcpy(StackEntryPtr, &E, sizeof(StackEntry));
+    break;
+  }
+  case XRayEntryType::EXIT:
+  case XRayEntryType::TAIL: {
+    if (TLD.StackEntries == 0)
+      break;
+
+    if (--TLD.StackEntries >= TLD.StackSize)
+      return;
+
+    // When we encounter an exit event, we check whether all the following are
+    // true:
+    //
+    // - The Function ID is the same as the most recent entry in the stack.
+    // - The CPU is the same as the most recent entry in the stack.
+    // - The Delta of the TSCs is less than the threshold amount of time we're
+    //   looking to record.
+    //
+    // If all of these conditions are true, we pop the stack and don't write a
+    // record and move the record offset back.
+    StackEntry StackTop;
+    auto StackEntryPtr = static_cast<char *>(TLD.ShadowStack) +
+                         (sizeof(StackEntry) * TLD.StackEntries);
+    internal_memcpy(&StackTop, StackEntryPtr, sizeof(StackEntry));
+    if (StackTop.FuncId == FuncId && StackTop.CPU == CPU &&
+        StackTop.TSC < TSC) {
+      auto Delta = TSC - StackTop.TSC;
+      if (Delta < atomic_load(&ThresholdTicks, memory_order_relaxed)) {
+        DCHECK(TLD.BufferOffset > 0);
+        TLD.BufferOffset -= StackTop.Type == XRayEntryType::ENTRY ? 1 : 2;
+        return;
+      }
+    }
+    break;
+  }
+  default:
+    // Should be unreachable.
+    DCHECK(false && "Unsupported XRayEntryType encountered.");
+    break;
+  }
+
+  // First determine whether the delta between the function's enter record and
+  // the exit record is higher than the threshold.
+  XRayRecord R;
+  R.RecordType = RecordTypes::NORMAL;
+  R.CPU = CPU;
+  R.TSC = TSC;
+  R.TId = GetTid(); 
+  R.PId = internal_getpid(); 
+  R.Type = Type;
+  R.FuncId = FuncId;
+  auto FirstEntry = reinterpret_cast<XRayRecord *>(TLD.InMemoryBuffer);
+  internal_memcpy(FirstEntry + TLD.BufferOffset, &R, sizeof(R));
+  if (++TLD.BufferOffset == TLD.BufferSize) {
+    SpinMutexLock Lock(&LogMutex);
+    LW->WriteAll(reinterpret_cast<char *>(FirstEntry),
+                 reinterpret_cast<char *>(FirstEntry + TLD.BufferOffset));
+    TLD.BufferOffset = 0;
+    TLD.StackEntries = 0;
+  }
+}
+
+template <class RDTSC>
+void InMemoryRawLogWithArg(int32_t FuncId, XRayEntryType Type, uint64_t Arg1,
+                           RDTSC ReadTSC) XRAY_NEVER_INSTRUMENT {
+  auto &TLD = getThreadLocalData();
+  auto FirstEntry =
+      reinterpret_cast<XRayArgPayload *>(TLD.InMemoryBuffer);
+  const auto &BuffLen = TLD.BufferSize;
+  LogWriter *LW = getGlobalLog();
+  if (LW == nullptr)
+    return;
+
+  // First we check whether there's enough space to write the data consecutively
+  // in the thread-local buffer. If not, we first flush the buffer before
+  // attempting to write the two records that must be consecutive.
+  if (TLD.BufferOffset + 2 > BuffLen) {
+    SpinMutexLock Lock(&LogMutex);
+    LW->WriteAll(reinterpret_cast<char *>(FirstEntry),
+                 reinterpret_cast<char *>(FirstEntry + TLD.BufferOffset));
+    TLD.BufferOffset = 0;
+    TLD.StackEntries = 0;
+  }
+
+  // Then we write the "we have an argument" record.
+  InMemoryRawLog(FuncId, Type, ReadTSC);
+
+  RecursionGuard G(Guard);
+  if (!G)
+    return;
+
+  // And, from here on write the arg payload.
+  XRayArgPayload R;
+  R.RecordType = RecordTypes::ARG_PAYLOAD;
+  R.FuncId = FuncId;
+  R.TId = GetTid(); 
+  R.PId = internal_getpid(); 
+  R.Arg = Arg1;
+  internal_memcpy(FirstEntry + TLD.BufferOffset, &R, sizeof(R));
+  if (++TLD.BufferOffset == BuffLen) {
+    SpinMutexLock Lock(&LogMutex);
+    LW->WriteAll(reinterpret_cast<char *>(FirstEntry),
+                 reinterpret_cast<char *>(FirstEntry + TLD.BufferOffset));
+    TLD.BufferOffset = 0;
+    TLD.StackEntries = 0;
+  }
+}
+
+void basicLoggingHandleArg0RealTSC(int32_t FuncId,
+                                   XRayEntryType Type) XRAY_NEVER_INSTRUMENT {
+  InMemoryRawLog(FuncId, Type, readTSC);
+}
+
+void basicLoggingHandleArg0EmulateTSC(int32_t FuncId, XRayEntryType Type)
+    XRAY_NEVER_INSTRUMENT {
+  InMemoryRawLog(FuncId, Type, [](uint8_t &CPU) XRAY_NEVER_INSTRUMENT {
+    timespec TS;
+    int result = clock_gettime(CLOCK_REALTIME, &TS);
+    if (result != 0) {
+      Report("clock_gettimg(2) return %d, errno=%d.", result, int(errno));
+      TS = {0, 0};
+    }
+    CPU = 0;
+    return TS.tv_sec * NanosecondsPerSecond + TS.tv_nsec;
+  });
+}
+
+void basicLoggingHandleArg1RealTSC(int32_t FuncId, XRayEntryType Type,
+                                   uint64_t Arg1) XRAY_NEVER_INSTRUMENT {
+  InMemoryRawLogWithArg(FuncId, Type, Arg1, readTSC);
+}
+
+void basicLoggingHandleArg1EmulateTSC(int32_t FuncId, XRayEntryType Type,
+                                      uint64_t Arg1) XRAY_NEVER_INSTRUMENT {
+  InMemoryRawLogWithArg(
+      FuncId, Type, Arg1, [](uint8_t &CPU) XRAY_NEVER_INSTRUMENT {
+        timespec TS;
+        int result = clock_gettime(CLOCK_REALTIME, &TS);
+        if (result != 0) {
+          Report("clock_gettimg(2) return %d, errno=%d.", result, int(errno));
+          TS = {0, 0};
+        }
+        CPU = 0;
+        return TS.tv_sec * NanosecondsPerSecond + TS.tv_nsec;
+      });
+}
+
+static void TLDDestructor(void *P) XRAY_NEVER_INSTRUMENT {
+  ThreadLocalData &TLD = *reinterpret_cast<ThreadLocalData *>(P);
+  auto ExitGuard = at_scope_exit([&TLD] {
+    // Clean up dynamic resources.
+    if (TLD.InMemoryBuffer)
+      InternalFree(TLD.InMemoryBuffer);
+    if (TLD.ShadowStack)
+      InternalFree(TLD.ShadowStack);
+    if (Verbosity())
+      Report("Cleaned up log for TID: %d\n", GetTid());
+  });
+
+  if (TLD.LogWriter == nullptr || TLD.BufferOffset == 0) {
+    if (Verbosity())
+      Report("Skipping buffer for TID: %d; Offset = %llu\n", GetTid(),
+             TLD.BufferOffset);
+    return;
+  }
+
+  {
+    SpinMutexLock L(&LogMutex);
+    TLD.LogWriter->WriteAll(reinterpret_cast<char *>(TLD.InMemoryBuffer),
+                            reinterpret_cast<char *>(TLD.InMemoryBuffer) +
+                            (sizeof(XRayRecord) * TLD.BufferOffset));
+  }
+
+  // Because this thread's exit could be the last one trying to write to
+  // the file and that we're not able to close out the file properly, we
+  // sync instead and hope that the pending writes are flushed as the
+  // thread exits.
+  TLD.LogWriter->Flush();
+}
+
+XRayLogInitStatus basicLoggingInit(UNUSED size_t BufferSize,
+                                   UNUSED size_t BufferMax, void *Options,
+                                   size_t OptionsSize) XRAY_NEVER_INSTRUMENT {
+  uint8_t Expected = 0;
+  if (!atomic_compare_exchange_strong(&BasicInitialized, &Expected, 1,
+                                      memory_order_acq_rel)) {
+    if (Verbosity())
+      Report("Basic logging already initialized.\n");
+    return XRayLogInitStatus::XRAY_LOG_INITIALIZED;
+  }
+
+  static pthread_once_t OnceInit = PTHREAD_ONCE_INIT;
+  pthread_once(&OnceInit, +[] {
+    pthread_key_create(&PThreadKey, TLDDestructor);
+    atomic_store(&UseRealTSC, probeRequiredCPUFeatures(), memory_order_release);
+    // Initialize the global TicksPerSec value.
+    atomic_store(&TicksPerSec,
+                 probeRequiredCPUFeatures() ? getTSCFrequency()
+                                            : NanosecondsPerSecond,
+                 memory_order_release);
+    if (!atomic_load(&UseRealTSC, memory_order_relaxed) && Verbosity())
+      Report("WARNING: Required CPU features missing for XRay instrumentation, "
+             "using emulation instead.\n");
+  });
+
+  FlagParser P;
+  BasicFlags F;
+  F.setDefaults();
+  registerXRayBasicFlags(&P, &F);
+  P.ParseString(useCompilerDefinedBasicFlags());
+  auto *EnvOpts = GetEnv("XRAY_BASIC_OPTIONS");
+  if (EnvOpts == nullptr)
+    EnvOpts = "";
+
+  P.ParseString(EnvOpts);
+
+  // If XRAY_BASIC_OPTIONS was not defined, then we use the deprecated options
+  // set through XRAY_OPTIONS instead.
+  if (internal_strlen(EnvOpts) == 0) {
+    F.func_duration_threshold_us =
+        flags()->xray_naive_log_func_duration_threshold_us;
+    F.max_stack_depth = flags()->xray_naive_log_max_stack_depth;
+    F.thread_buffer_size = flags()->xray_naive_log_thread_buffer_size;
+  }
+
+  P.ParseString(static_cast<const char *>(Options));
+  GlobalOptions.ThreadBufferSize = F.thread_buffer_size;
+  GlobalOptions.DurationFilterMicros = F.func_duration_threshold_us;
+  GlobalOptions.MaxStackDepth = F.max_stack_depth;
+  *basicFlags() = F;
+
+  atomic_store(&ThresholdTicks,
+               atomic_load(&TicksPerSec, memory_order_acquire) *
+                   GlobalOptions.DurationFilterMicros / 1000000,
+               memory_order_release);
+  __xray_set_handler_arg1(atomic_load(&UseRealTSC, memory_order_acquire)
+                              ? basicLoggingHandleArg1RealTSC
+                              : basicLoggingHandleArg1EmulateTSC);
+  __xray_set_handler(atomic_load(&UseRealTSC, memory_order_acquire)
+                         ? basicLoggingHandleArg0RealTSC
+                         : basicLoggingHandleArg0EmulateTSC);
+
+  // TODO: Implement custom event and typed event handling support in Basic
+  // Mode.
+  __xray_remove_customevent_handler();
+  __xray_remove_typedevent_handler();
+
+  return XRayLogInitStatus::XRAY_LOG_INITIALIZED;
+}
+
+XRayLogInitStatus basicLoggingFinalize() XRAY_NEVER_INSTRUMENT {
+  uint8_t Expected = 0;
+  if (!atomic_compare_exchange_strong(&BasicInitialized, &Expected, 0,
+                                      memory_order_acq_rel) &&
+      Verbosity())
+    Report("Basic logging already finalized.\n");
+
+  // Nothing really to do aside from marking state of the global to be
+  // uninitialized.
+
+  return XRayLogInitStatus::XRAY_LOG_FINALIZED;
+}
+
+XRayLogFlushStatus basicLoggingFlush() XRAY_NEVER_INSTRUMENT {
+  // This really does nothing, since flushing the logs happen at the end of a
+  // thread's lifetime, or when the buffers are full.
+  return XRayLogFlushStatus::XRAY_LOG_FLUSHED;
+}
+
+// This is a handler that, effectively, does nothing.
+void basicLoggingHandleArg0Empty(int32_t, XRayEntryType) XRAY_NEVER_INSTRUMENT {
+}
+
+bool basicLogDynamicInitializer() XRAY_NEVER_INSTRUMENT {
+  XRayLogImpl Impl{
+      basicLoggingInit,
+      basicLoggingFinalize,
+      basicLoggingHandleArg0Empty,
+      basicLoggingFlush,
+  };
+  auto RegistrationResult = __xray_log_register_mode("xray-basic", Impl);
+  if (RegistrationResult != XRayLogRegisterStatus::XRAY_REGISTRATION_OK &&
+      Verbosity())
+    Report("Cannot register XRay Basic Mode to 'xray-basic'; error = %d\n",
+           RegistrationResult);
+  if (flags()->xray_naive_log ||
+      !internal_strcmp(flags()->xray_mode, "xray-basic")) {
+    auto SelectResult = __xray_log_select_mode("xray-basic");
+    if (SelectResult != XRayLogRegisterStatus::XRAY_REGISTRATION_OK) {
+      if (Verbosity())
+        Report("Failed selecting XRay Basic Mode; error = %d\n", SelectResult);
+      return false;
+    }
+
+    // We initialize the implementation using the data we get from the
+    // XRAY_BASIC_OPTIONS environment variable, at this point of the
+    // implementation.
+    auto *Env = GetEnv("XRAY_BASIC_OPTIONS");
+    auto InitResult =
+        __xray_log_init_mode("xray-basic", Env == nullptr ? "" : Env);
+    if (InitResult != XRayLogInitStatus::XRAY_LOG_INITIALIZED) {
+      if (Verbosity())
+        Report("Failed initializing XRay Basic Mode; error = %d\n", InitResult);
+      return false;
+    }
+
+    // At this point we know that we've successfully initialized Basic mode
+    // tracing, and the only chance we're going to get for the current thread to
+    // clean-up may be at thread/program exit. To ensure that we're going to get
+    // the cleanup even without calling the finalization routines, we're
+    // registering a program exit function that will do the cleanup.
+    static pthread_once_t DynamicOnce = PTHREAD_ONCE_INIT;
+    pthread_once(&DynamicOnce, +[] {
+      static void *FakeTLD = nullptr;
+      FakeTLD = &getThreadLocalData();
+      Atexit(+[] { TLDDestructor(FakeTLD); });
+    });
+  }
+  return true;
+}
+
+} // namespace __xray
+
+static auto UNUSED Unused = __xray::basicLogDynamicInitializer();