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 #include "sanitizer_common/sanitizer_platform_limits_freebsd.h"
21 #include "sanitizer_common/sanitizer_platform_limits_posix.h"
22 
23 namespace __esan {
24 
25 typedef void (*SidelineFunc)(void *Arg);
26 
27 // Currently only one sideline thread is supported.
28 // It calls the SidelineFunc passed to launchThread once on each sample at the
29 // given frequency in real time (i.e., wall clock time).
30 class SidelineThread {
31 public:
32   // We cannot initialize any fields in the constructor as it will be called
33   // *after* launchThread for a static instance, as esan.module_ctor is called
34   // before static initializers.
SidelineThread()35   SidelineThread() {}
~SidelineThread()36   ~SidelineThread() {}
37 
38   // To simplify declaration in sanitizer code where we want to avoid
39   // heap allocations, the constructor and destructor do nothing and
40   // launchThread and joinThread do the real work.
41   // They should each be called just once.
42   bool launchThread(SidelineFunc takeSample, void *Arg, u32 FreqMilliSec);
43   bool joinThread();
44 
45   // Must be called from the sideline thread itself.
46   bool adjustTimer(u32 FreqMilliSec);
47 
48 private:
49   static int runSideline(void *Arg);
50   static void registerSignal(int SigNum);
51   static void handleSidelineSignal(int SigNum, __sanitizer_siginfo *SigInfo,
52                                    void *Ctx);
53 
54   char *Stack;
55   SidelineFunc sampleFunc;
56   void *FuncArg;
57   u32 Freq;
58   uptr SidelineId;
59   atomic_uintptr_t SidelineExit;
60 };
61 
62 } // namespace __esan
63 
64 #endif  // ESAN_SIDELINE_H
65