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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.
SidelineThread()33   SidelineThread() {}
~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
62