/*
* Copyright (c) Meta Platforms, Inc. and affiliates.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#pragma once
// clang-format off
#include <cstddef>
// Default constraint for the probe arguments as operands.
#ifndef FOLLY_SDT_ARG_CONSTRAINT
#define FOLLY_SDT_ARG_CONSTRAINT "nor"
#endif
// Instruction to emit for the probe.
#if defined(__x86_64__) || defined(__i386__)
#define FOLLY_SDT_NOP nop
#elif defined(__aarch64__) || defined(__arm__)
#define FOLLY_SDT_NOP nop
#else
#error "Unsupported architecture"
#endif
// Note section properties.
#define FOLLY_SDT_NOTE_NAME "stapsdt"
#define FOLLY_SDT_NOTE_TYPE 3
// Semaphore variables are put in this section
#define FOLLY_SDT_SEMAPHORE_SECTION ".probes"
// Size of address depending on platform.
#ifdef __LP64__
#define FOLLY_SDT_ASM_ADDR .8byte
#else
#define FOLLY_SDT_ASM_ADDR .4byte
#endif
// Assembler helper Macros.
#define FOLLY_SDT_S(x) #x
#define FOLLY_SDT_ASM_1(x) FOLLY_SDT_S(x) "\n"
#define FOLLY_SDT_ASM_2(a, b) FOLLY_SDT_S(a) "," FOLLY_SDT_S(b) "\n"
#define FOLLY_SDT_ASM_3(a, b, c) FOLLY_SDT_S(a) "," FOLLY_SDT_S(b) "," \
FOLLY_SDT_S(c) "\n"
#define FOLLY_SDT_ASM_STRING(x) FOLLY_SDT_ASM_1(.asciz FOLLY_SDT_S(x))
// Helper to determine the size of an argument.
#define FOLLY_SDT_IS_ARRAY_POINTER(x) ((__builtin_classify_type(x) == 14) || \
(__builtin_classify_type(x) == 5))
#define FOLLY_SDT_ARGSIZE(x) (FOLLY_SDT_IS_ARRAY_POINTER(x) \
? sizeof(void*) \
: sizeof(x))
// Format of each probe arguments as operand.
// Size of the argument tagged with FOLLY_SDT_Sn, with "n" constraint.
// Value of the argument tagged with FOLLY_SDT_An, with configured constraint.
#define FOLLY_SDT_ARG(n, x) \
[FOLLY_SDT_S##n] "n" ((size_t)FOLLY_SDT_ARGSIZE(x)), \
[FOLLY_SDT_A##n] FOLLY_SDT_ARG_CONSTRAINT (x)
// Templates to append arguments as operands.
#define FOLLY_SDT_OPERANDS_0() [__sdt_dummy] "g" (0)
#define FOLLY_SDT_OPERANDS_1(_1) FOLLY_SDT_ARG(1, _1)
#define FOLLY_SDT_OPERANDS_2(_1, _2) \
FOLLY_SDT_OPERANDS_1(_1), FOLLY_SDT_ARG(2, _2)
#define FOLLY_SDT_OPERANDS_3(_1, _2, _3) \
FOLLY_SDT_OPERANDS_2(_1, _2), FOLLY_SDT_ARG(3, _3)
#define FOLLY_SDT_OPERANDS_4(_1, _2, _3, _4) \
FOLLY_SDT_OPERANDS_3(_1, _2, _3), FOLLY_SDT_ARG(4, _4)
#define FOLLY_SDT_OPERANDS_5(_1, _2, _3, _4, _5) \
FOLLY_SDT_OPERANDS_4(_1, _2, _3, _4), FOLLY_SDT_ARG(5, _5)
#define FOLLY_SDT_OPERANDS_6(_1, _2, _3, _4, _5, _6) \
FOLLY_SDT_OPERANDS_5(_1, _2, _3, _4, _5), FOLLY_SDT_ARG(6, _6)
#define FOLLY_SDT_OPERANDS_7(_1, _2, _3, _4, _5, _6, _7) \
FOLLY_SDT_OPERANDS_6(_1, _2, _3, _4, _5, _6), FOLLY_SDT_ARG(7, _7)
#define FOLLY_SDT_OPERANDS_8(_1, _2, _3, _4, _5, _6, _7, _8) \
FOLLY_SDT_OPERANDS_7(_1, _2, _3, _4, _5, _6, _7), FOLLY_SDT_ARG(8, _8)
#define FOLLY_SDT_OPERANDS_9(_1, _2, _3, _4, _5, _6, _7, _8, _9) \
FOLLY_SDT_OPERANDS_8(_1, _2, _3, _4, _5, _6, _7, _8), FOLLY_SDT_ARG(9, _9)
// Templates to reference the arguments from operands in note section.
#define FOLLY_SDT_ARGFMT(no) %n[FOLLY_SDT_S##no]@%[FOLLY_SDT_A##no]
#define FOLLY_SDT_ARG_TEMPLATE_0 /*No arguments*/
#define FOLLY_SDT_ARG_TEMPLATE_1 FOLLY_SDT_ARGFMT(1)
#define FOLLY_SDT_ARG_TEMPLATE_2 FOLLY_SDT_ARG_TEMPLATE_1 FOLLY_SDT_ARGFMT(2)
#define FOLLY_SDT_ARG_TEMPLATE_3 FOLLY_SDT_ARG_TEMPLATE_2 FOLLY_SDT_ARGFMT(3)
#define FOLLY_SDT_ARG_TEMPLATE_4 FOLLY_SDT_ARG_TEMPLATE_3 FOLLY_SDT_ARGFMT(4)
#define FOLLY_SDT_ARG_TEMPLATE_5 FOLLY_SDT_ARG_TEMPLATE_4 FOLLY_SDT_ARGFMT(5)
#define FOLLY_SDT_ARG_TEMPLATE_6 FOLLY_SDT_ARG_TEMPLATE_5 FOLLY_SDT_ARGFMT(6)
#define FOLLY_SDT_ARG_TEMPLATE_7 FOLLY_SDT_ARG_TEMPLATE_6 FOLLY_SDT_ARGFMT(7)
#define FOLLY_SDT_ARG_TEMPLATE_8 FOLLY_SDT_ARG_TEMPLATE_7 FOLLY_SDT_ARGFMT(8)
#define FOLLY_SDT_ARG_TEMPLATE_9 FOLLY_SDT_ARG_TEMPLATE_8 FOLLY_SDT_ARGFMT(9)
// Semaphore define, declare and probe note format
#define FOLLY_SDT_SEMAPHORE(provider, name) \
folly_sdt_semaphore_##provider##_##name
#define FOLLY_SDT_DEFINE_SEMAPHORE(provider, name) \
extern "C" { \
volatile unsigned short FOLLY_SDT_SEMAPHORE(provider, name) \
__attribute__((section(FOLLY_SDT_SEMAPHORE_SECTION), used)) = 0; \
}
#define FOLLY_SDT_DECLARE_SEMAPHORE(provider, name) \
extern "C" volatile unsigned short FOLLY_SDT_SEMAPHORE(provider, name)
#define FOLLY_SDT_SEMAPHORE_NOTE_0(provider, name) \
FOLLY_SDT_ASM_1( FOLLY_SDT_ASM_ADDR 0) /*No Semaphore*/ \
#define FOLLY_SDT_SEMAPHORE_NOTE_1(provider, name) \
FOLLY_SDT_ASM_1(FOLLY_SDT_ASM_ADDR FOLLY_SDT_SEMAPHORE(provider, name))
#define FOLLY_SDT_SEMAPHORE_OPERAND_0(provider, name) \
[__sdt_semaphore] "ip" (0) /*No Semaphore*/
#define FOLLY_SDT_SEMAPHORE_OPERAND_1(provider, name) \
[__sdt_semaphore] "ip" (&FOLLY_SDT_SEMAPHORE(provider, name))
// Structure of note section for the probe.
#define FOLLY_SDT_NOTE_CONTENT(provider, name, has_semaphore, arg_template) \
FOLLY_SDT_ASM_1(990: FOLLY_SDT_NOP) \
FOLLY_SDT_ASM_3( .pushsection .note.stapsdt,"","note") \
FOLLY_SDT_ASM_1( .balign 4) \
FOLLY_SDT_ASM_3( .4byte 992f-991f, 994f-993f, FOLLY_SDT_NOTE_TYPE) \
FOLLY_SDT_ASM_1(991: .asciz FOLLY_SDT_NOTE_NAME) \
FOLLY_SDT_ASM_1(992: .balign 4) \
FOLLY_SDT_ASM_1(993: FOLLY_SDT_ASM_ADDR 990b) \
FOLLY_SDT_ASM_1( FOLLY_SDT_ASM_ADDR 0) /*Reserved for Base Address*/ \
FOLLY_SDT_SEMAPHORE_NOTE_##has_semaphore(provider, name) \
FOLLY_SDT_ASM_STRING(provider) \
FOLLY_SDT_ASM_STRING(name) \
FOLLY_SDT_ASM_STRING(arg_template) \
FOLLY_SDT_ASM_1(994: .balign 4) \
FOLLY_SDT_ASM_1( .popsection)
// Main probe Macro.
#define FOLLY_SDT_PROBE(provider, name, has_semaphore, n, arglist) \
__asm__ __volatile__ ( \
FOLLY_SDT_NOTE_CONTENT( \
provider, name, has_semaphore, FOLLY_SDT_ARG_TEMPLATE_##n) \
:: FOLLY_SDT_SEMAPHORE_OPERAND_##has_semaphore(provider, name), \
FOLLY_SDT_OPERANDS_##n arglist \
) \
// Helper Macros to handle variadic arguments.
#define FOLLY_SDT_NARG_(_0, _1, _2, _3, _4, _5, _6, _7, _8, _9, N, ...) N
#define FOLLY_SDT_NARG(...) \
FOLLY_SDT_NARG_(__VA_ARGS__, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0)
#define FOLLY_SDT_PROBE_N(provider, name, has_semaphore, N, ...) \
FOLLY_SDT_PROBE(provider, name, has_semaphore, N, (__VA_ARGS__))
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