src/libcompiler_builtins/compiler-rt/include/xray/xray_interface.h

   1 //===- xray_interface.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 XRay, a dynamic runtime instrumentation system.
  11 //
  12 // APIs for controlling XRay functionality explicitly.
  13 //===----------------------------------------------------------------------===//
  14
  15 #ifndef XRAY_XRAY_INTERFACE_H
  16 #define XRAY_XRAY_INTERFACE_H
  17
  18 #include <cstddef>
  19 #include <cstdint>
  20
  21 extern "C" {
  22
  23 /// Synchronize this with AsmPrinter::SledKind in LLVM.
  24 enum XRayEntryType {
  25   ENTRY = 0,
  26   EXIT = 1,
  27   TAIL = 2,
  28   LOG_ARGS_ENTRY = 3,
  29   CUSTOM_EVENT = 4,
  30 };
  31
  32 /// Provide a function to invoke for when instrumentation points are hit. This
  33 /// is a user-visible control surface that overrides the default implementation.
  34 /// The function provided should take the following arguments:
  35 ///
  36 ///   - function id: an identifier that indicates the id of a function; this id
  37 ///                  is generated by xray; the mapping between the function id
  38 ///                  and the actual function pointer is available through
  39 ///                  __xray_table.
  40 ///   - entry type: identifies what kind of instrumentation point was
  41 ///                 encountered (function entry, function exit, etc.). See the
  42 ///                 enum XRayEntryType for more details.
  43 ///
  44 /// The user handler must handle correctly spurious calls after this handler is
  45 /// removed or replaced with another handler, because it would be too costly for
  46 /// XRay runtime to avoid spurious calls.
  47 /// To prevent circular calling, the handler function itself and all its
  48 /// direct&indirect callees must not be instrumented with XRay, which can be
  49 /// achieved by marking them all with: __attribute__((xray_never_instrument))
  50 ///
  51 /// Returns 1 on success, 0 on error.
  52 extern int __xray_set_handler(void (*entry)(int32_t, XRayEntryType));
  53
  54 /// This removes whatever the currently provided handler is. Returns 1 on
  55 /// success, 0 on error.
  56 extern int __xray_remove_handler();
  57
  58 /// Use XRay to log the first argument of each (instrumented) function call.
  59 /// When this function exits, all threads will have observed the effect and
  60 /// start logging their subsequent affected function calls (if patched).
  61 ///
  62 /// Returns 1 on success, 0 on error.
  63 extern int __xray_set_handler_arg1(void (*entry)(int32_t, XRayEntryType,
  64                                                  uint64_t));
  65
  66 /// Disables the XRay handler used to log first arguments of function calls.
  67 /// Returns 1 on success, 0 on error.
  68 extern int __xray_remove_handler_arg1();
  69
  70 /// Provide a function to invoke when XRay encounters a custom event.
  71 extern int __xray_set_customevent_handler(void (*entry)(void*, std::size_t));
  72
  73 /// This removes whatever the currently provided custom event handler is.
  74 /// Returns 1 on success, 0 on error.
  75 extern int __xray_remove_customevent_handler();
  76
  77 enum XRayPatchingStatus {
  78   NOT_INITIALIZED = 0,
  79   SUCCESS = 1,
  80   ONGOING = 2,
  81   FAILED = 3,
  82 };
  83
  84 /// This tells XRay to patch the instrumentation points. See XRayPatchingStatus
  85 /// for possible result values.
  86 extern XRayPatchingStatus __xray_patch();
  87
  88 /// Reverses the effect of __xray_patch(). See XRayPatchingStatus for possible
  89 /// result values.
  90 extern XRayPatchingStatus __xray_unpatch();
  91
  92 /// This patches a specific function id. See XRayPatchingStatus for possible
  93 /// result values.
  94 extern XRayPatchingStatus __xray_patch_function(int32_t FuncId);
  95
  96 /// This unpatches a specific function id. See XRayPatchingStatus for possible
  97 /// result values.
  98 extern XRayPatchingStatus __xray_unpatch_function(int32_t FuncId);
  99
 100 /// This function returns the address of the function provided a valid function
 101 /// id. We return 0 if we encounter any error, even if 0 may be a valid function
 102 /// address.
 103 extern uintptr_t __xray_function_address(int32_t FuncId);
 104
 105 /// This function returns the maximum valid function id. Returns 0 if we
 106 /// encounter errors (when there are no instrumented functions, etc.).
 107 extern size_t __xray_max_function_id();
 108
 109 /// Initialize the required XRay data structures. This is useful in cases where
 110 /// users want to control precisely when the XRay instrumentation data
 111 /// structures are initialized, for example when the XRay library is built with
 112 /// the XRAY_NO_PREINIT preprocessor definition.
 113 ///
 114 /// Calling __xray_init() more than once is safe across multiple threads.
 115 extern void __xray_init();
 116
 117 } // end extern "C"
 118
 119 #endif // XRAY_XRAY_INTERFACE_H