1/*
2 * Copyright 2016-present Facebook, Inc.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#pragma once
18
19// clang-format off
20#include <cstddef>
21
22// Default constraint for the probe arguments as operands.
23#ifndef FOLLY_SDT_ARG_CONSTRAINT
24#define FOLLY_SDT_ARG_CONSTRAINT "nor"
25#endif
26
27// Instruction to emit for the probe.
28#define FOLLY_SDT_NOP nop
29
30// Note section properties.
31#define FOLLY_SDT_NOTE_NAME "stapsdt"
32#define FOLLY_SDT_NOTE_TYPE 3
33
34// Semaphore variables are put in this section
35#define FOLLY_SDT_SEMAPHORE_SECTION ".probes"
36
37// Size of address depending on platform.
38#ifdef __LP64__
39#define FOLLY_SDT_ASM_ADDR .8byte
40#else
41#define FOLLY_SDT_ASM_ADDR .4byte
42#endif
43
44// Assembler helper Macros.
45#define FOLLY_SDT_S(x) #x
46#define FOLLY_SDT_ASM_1(x) FOLLY_SDT_S(x) "\n"
47#define FOLLY_SDT_ASM_2(a, b) FOLLY_SDT_S(a) "," FOLLY_SDT_S(b) "\n"
48#define FOLLY_SDT_ASM_3(a, b, c) FOLLY_SDT_S(a) "," FOLLY_SDT_S(b) "," \
49 FOLLY_SDT_S(c) "\n"
50#define FOLLY_SDT_ASM_STRING(x) FOLLY_SDT_ASM_1(.asciz FOLLY_SDT_S(x))
51
52// Helper to determine the size of an argument.
53#define FOLLY_SDT_IS_ARRAY_POINTER(x) ((__builtin_classify_type(x) == 14) || \
54 (__builtin_classify_type(x) == 5))
55#define FOLLY_SDT_ARGSIZE(x) (FOLLY_SDT_IS_ARRAY_POINTER(x) \
56 ? sizeof(void*) \
57 : sizeof(x))
58
59// Format of each probe arguments as operand.
60// Size of the arugment tagged with FOLLY_SDT_Sn, with "n" constraint.
61// Value of the argument tagged with FOLLY_SDT_An, with configured constraint.
62#define FOLLY_SDT_ARG(n, x) \
63 [FOLLY_SDT_S##n] "n" ((size_t)FOLLY_SDT_ARGSIZE(x)), \
64 [FOLLY_SDT_A##n] FOLLY_SDT_ARG_CONSTRAINT (x)
65
66// Templates to append arguments as operands.
67#define FOLLY_SDT_OPERANDS_0() [__sdt_dummy] "g" (0)
68#define FOLLY_SDT_OPERANDS_1(_1) FOLLY_SDT_ARG(1, _1)
69#define FOLLY_SDT_OPERANDS_2(_1, _2) \
70 FOLLY_SDT_OPERANDS_1(_1), FOLLY_SDT_ARG(2, _2)
71#define FOLLY_SDT_OPERANDS_3(_1, _2, _3) \
72 FOLLY_SDT_OPERANDS_2(_1, _2), FOLLY_SDT_ARG(3, _3)
73#define FOLLY_SDT_OPERANDS_4(_1, _2, _3, _4) \
74 FOLLY_SDT_OPERANDS_3(_1, _2, _3), FOLLY_SDT_ARG(4, _4)
75#define FOLLY_SDT_OPERANDS_5(_1, _2, _3, _4, _5) \
76 FOLLY_SDT_OPERANDS_4(_1, _2, _3, _4), FOLLY_SDT_ARG(5, _5)
77#define FOLLY_SDT_OPERANDS_6(_1, _2, _3, _4, _5, _6) \
78 FOLLY_SDT_OPERANDS_5(_1, _2, _3, _4, _5), FOLLY_SDT_ARG(6, _6)
79#define FOLLY_SDT_OPERANDS_7(_1, _2, _3, _4, _5, _6, _7) \
80 FOLLY_SDT_OPERANDS_6(_1, _2, _3, _4, _5, _6), FOLLY_SDT_ARG(7, _7)
81#define FOLLY_SDT_OPERANDS_8(_1, _2, _3, _4, _5, _6, _7, _8) \
82 FOLLY_SDT_OPERANDS_7(_1, _2, _3, _4, _5, _6, _7), FOLLY_SDT_ARG(8, _8)
83#define FOLLY_SDT_OPERANDS_9(_1, _2, _3, _4, _5, _6, _7, _8, _9) \
84 FOLLY_SDT_OPERANDS_8(_1, _2, _3, _4, _5, _6, _7, _8), FOLLY_SDT_ARG(9, _9)
85
86// Templates to reference the arguments from operands in note section.
87#define FOLLY_SDT_ARGFMT(no) %n[FOLLY_SDT_S##no]@%[FOLLY_SDT_A##no]
88#define FOLLY_SDT_ARG_TEMPLATE_0 /*No arguments*/
89#define FOLLY_SDT_ARG_TEMPLATE_1 FOLLY_SDT_ARGFMT(1)
90#define FOLLY_SDT_ARG_TEMPLATE_2 FOLLY_SDT_ARG_TEMPLATE_1 FOLLY_SDT_ARGFMT(2)
91#define FOLLY_SDT_ARG_TEMPLATE_3 FOLLY_SDT_ARG_TEMPLATE_2 FOLLY_SDT_ARGFMT(3)
92#define FOLLY_SDT_ARG_TEMPLATE_4 FOLLY_SDT_ARG_TEMPLATE_3 FOLLY_SDT_ARGFMT(4)
93#define FOLLY_SDT_ARG_TEMPLATE_5 FOLLY_SDT_ARG_TEMPLATE_4 FOLLY_SDT_ARGFMT(5)
94#define FOLLY_SDT_ARG_TEMPLATE_6 FOLLY_SDT_ARG_TEMPLATE_5 FOLLY_SDT_ARGFMT(6)
95#define FOLLY_SDT_ARG_TEMPLATE_7 FOLLY_SDT_ARG_TEMPLATE_6 FOLLY_SDT_ARGFMT(7)
96#define FOLLY_SDT_ARG_TEMPLATE_8 FOLLY_SDT_ARG_TEMPLATE_7 FOLLY_SDT_ARGFMT(8)
97#define FOLLY_SDT_ARG_TEMPLATE_9 FOLLY_SDT_ARG_TEMPLATE_8 FOLLY_SDT_ARGFMT(9)
98
99// Semaphore define, declare and probe note format
100
101#define FOLLY_SDT_SEMAPHORE(provider, name) \
102 folly_sdt_semaphore_##provider##_##name
103
104#define FOLLY_SDT_DEFINE_SEMAPHORE(provider, name) \
105 extern "C" { \
106 volatile unsigned short FOLLY_SDT_SEMAPHORE(provider, name) \
107 __attribute__((section(FOLLY_SDT_SEMAPHORE_SECTION), used)) = 0; \
108 }
109
110#define FOLLY_SDT_DECLARE_SEMAPHORE(provider, name) \
111 extern "C" volatile unsigned short FOLLY_SDT_SEMAPHORE(provider, name)
112
113#define FOLLY_SDT_SEMAPHORE_NOTE_0(provider, name) \
114 FOLLY_SDT_ASM_1( FOLLY_SDT_ASM_ADDR 0) /*No Semaphore*/ \
115
116#define FOLLY_SDT_SEMAPHORE_NOTE_1(provider, name) \
117 FOLLY_SDT_ASM_1(FOLLY_SDT_ASM_ADDR FOLLY_SDT_SEMAPHORE(provider, name))
118
119// Structure of note section for the probe.
120#define FOLLY_SDT_NOTE_CONTENT(provider, name, has_semaphore, arg_template) \
121 FOLLY_SDT_ASM_1(990: FOLLY_SDT_NOP) \
122 FOLLY_SDT_ASM_3( .pushsection .note.stapsdt,"","note") \
123 FOLLY_SDT_ASM_1( .balign 4) \
124 FOLLY_SDT_ASM_3( .4byte 992f-991f, 994f-993f, FOLLY_SDT_NOTE_TYPE) \
125 FOLLY_SDT_ASM_1(991: .asciz FOLLY_SDT_NOTE_NAME) \
126 FOLLY_SDT_ASM_1(992: .balign 4) \
127 FOLLY_SDT_ASM_1(993: FOLLY_SDT_ASM_ADDR 990b) \
128 FOLLY_SDT_ASM_1( FOLLY_SDT_ASM_ADDR 0) /*Reserved for Base Address*/ \
129 FOLLY_SDT_SEMAPHORE_NOTE_##has_semaphore(provider, name) \
130 FOLLY_SDT_ASM_STRING(provider) \
131 FOLLY_SDT_ASM_STRING(name) \
132 FOLLY_SDT_ASM_STRING(arg_template) \
133 FOLLY_SDT_ASM_1(994: .balign 4) \
134 FOLLY_SDT_ASM_1( .popsection)
135
136// Main probe Macro.
137#define FOLLY_SDT_PROBE(provider, name, has_semaphore, n, arglist) \
138 __asm__ __volatile__ ( \
139 FOLLY_SDT_NOTE_CONTENT( \
140 provider, name, has_semaphore, FOLLY_SDT_ARG_TEMPLATE_##n) \
141 :: FOLLY_SDT_OPERANDS_##n arglist \
142 ) \
143
144// Helper Macros to handle variadic arguments.
145#define FOLLY_SDT_NARG_(_0, _1, _2, _3, _4, _5, _6, _7, _8, _9, N, ...) N
146#define FOLLY_SDT_NARG(...) \
147 FOLLY_SDT_NARG_(__VA_ARGS__, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0)
148#define FOLLY_SDT_PROBE_N(provider, name, has_semaphore, N, ...) \
149 FOLLY_SDT_PROBE(provider, name, has_semaphore, N, (__VA_ARGS__))
150