src/compiler-rt/lib/esan/esan_sideline.h

   1 //===-- esan_sideline.h -----------------------------------------*- C++ -*-===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This file is a part of EfficiencySanitizer, a family of performance tuners.
  11 //
  12 // Esan sideline thread support.
  13 //===----------------------------------------------------------------------===//
  14
  15 #ifndef ESAN_SIDELINE_H
  16 #define ESAN_SIDELINE_H
  17
  18 #include "sanitizer_common/sanitizer_atomic.h"
  19 #include "sanitizer_common/sanitizer_internal_defs.h"
  20
  21 namespace __esan {
  22
  23 typedef void (*SidelineFunc)(void *Arg);
  24
  25 // Currently only one sideline thread is supported.
  26 // It calls the SidelineFunc passed to launchThread once on each sample at the
  27 // given frequency in real time (i.e., wall clock time).
  28 class SidelineThread {
  29 public:
  30   // We cannot initialize any fields in the constructor as it will be called
  31   // *after* launchThread for a static instance, as esan.module_ctor is called
  32   // before static initializers.
  33   SidelineThread() {}
  34   ~SidelineThread() {}
  35
  36   // To simplify declaration in sanitizer code where we want to avoid
  37   // heap allocations, the constructor and destructor do nothing and
  38   // launchThread and joinThread do the real work.
  39   // They should each be called just once.
  40   bool launchThread(SidelineFunc takeSample, void *Arg, u32 FreqMilliSec);
  41   bool joinThread();
  42
  43   // Must be called from the sideline thread itself.
  44   bool adjustTimer(u32 FreqMilliSec);
  45
  46 private:
  47   static int runSideline(void *Arg);
  48   static void registerSignal(int SigNum);
  49   static void handleSidelineSignal(int SigNum, void *SigInfo, void *Ctx);
  50
  51   char *Stack;
  52   SidelineFunc sampleFunc;
  53   void *FuncArg;
  54   u32 Freq;
  55   uptr SidelineId;
  56   atomic_uintptr_t SidelineExit;
  57 };
  58
  59 } // namespace __esan
  60
  61 #endif  // ESAN_SIDELINE_H