1 //===- xray_interface.h -----------------------------------------*- C++ -*-===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file is a part of XRay, a dynamic runtime instrumentation system. 10 // 11 // APIs for controlling XRay functionality explicitly. 12 //===----------------------------------------------------------------------===// 13 14 #ifndef XRAY_XRAY_INTERFACE_H 15 #define XRAY_XRAY_INTERFACE_H 16 17 #include <cstddef> 18 #include <cstdint> 19 20 extern "C" { 21 22 /// Synchronize this with AsmPrinter::SledKind in LLVM. 23 enum XRayEntryType { 24 ENTRY = 0, 25 EXIT = 1, 26 TAIL = 2, 27 LOG_ARGS_ENTRY = 3, 28 CUSTOM_EVENT = 4, 29 TYPED_EVENT = 5, 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 /// Set a handler for xray typed event logging. The first parameter is a type 78 /// identifier, the second is a payload, and the third is the payload size. 79 /// NOTE: fdrLoggingHandleTypedEvent only supports uint16_t event type. 80 extern int __xray_set_typedevent_handler(void (*entry)(size_t, const void *, 81 size_t)); 82 83 /// Removes the currently set typed event handler. 84 /// Returns 1 on success, 0 on error. 85 extern int __xray_remove_typedevent_handler(); 86 87 extern uint16_t __xray_register_event_type(const char *event_type); 88 89 enum XRayPatchingStatus { 90 NOT_INITIALIZED = 0, 91 SUCCESS = 1, 92 ONGOING = 2, 93 FAILED = 3, 94 }; 95 96 /// This tells XRay to patch the instrumentation points. See XRayPatchingStatus 97 /// for possible result values. 98 extern XRayPatchingStatus __xray_patch(); 99 100 /// Reverses the effect of __xray_patch(). See XRayPatchingStatus for possible 101 /// result values. 102 extern XRayPatchingStatus __xray_unpatch(); 103 104 /// This patches a specific function id. See XRayPatchingStatus for possible 105 /// result values. 106 extern XRayPatchingStatus __xray_patch_function(int32_t FuncId); 107 108 /// This unpatches a specific function id. See XRayPatchingStatus for possible 109 /// result values. 110 extern XRayPatchingStatus __xray_unpatch_function(int32_t FuncId); 111 112 /// This function returns the address of the function provided a valid function 113 /// id. We return 0 if we encounter any error, even if 0 may be a valid function 114 /// address. 115 extern uintptr_t __xray_function_address(int32_t FuncId); 116 117 /// This function returns the maximum valid function id. Returns 0 if we 118 /// encounter errors (when there are no instrumented functions, etc.). 119 extern size_t __xray_max_function_id(); 120 121 /// Initialize the required XRay data structures. This is useful in cases where 122 /// users want to control precisely when the XRay instrumentation data 123 /// structures are initialized, for example when the XRay library is built with 124 /// the XRAY_NO_PREINIT preprocessor definition. 125 /// 126 /// Calling __xray_init() more than once is safe across multiple threads. 127 extern void __xray_init(); 128 129 } // end extern "C" 130 131 #endif // XRAY_XRAY_INTERFACE_H 132