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
20extern "C" {
21
22/// Synchronize this with AsmPrinter::SledKind in LLVM.
23enum 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.
52extern 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.
56extern 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.
63extern 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.
68extern int __xray_remove_handler_arg1();
69
70/// Provide a function to invoke when XRay encounters a custom event.
71extern 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.
75extern 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.
80extern 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.
85extern int __xray_remove_typedevent_handler();
86
87extern uint16_t __xray_register_event_type(const char *event_type);
88
89enum 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.
98extern XRayPatchingStatus __xray_patch();
99
100/// Reverses the effect of __xray_patch(). See XRayPatchingStatus for possible
101/// result values.
102extern XRayPatchingStatus __xray_unpatch();
103
104/// This patches a specific function id. See XRayPatchingStatus for possible
105/// result values.
106extern XRayPatchingStatus __xray_patch_function(int32_t FuncId);
107
108/// This unpatches a specific function id. See XRayPatchingStatus for possible
109/// result values.
110extern 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.
115extern 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.).
119extern 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.
127extern void __xray_init();
128
129} // end extern "C"
130
131#endif // XRAY_XRAY_INTERFACE_H
132