linux/tools/testing/selftests/bpf/progs/pyperf180.c

// SPDX-License-Identifier: GPL-2.0
// Copyright (c) 2019 Facebook
#define STACK_MAX_LEN 180

/* llvm upstream commit at clang18
 *   https://github.com/llvm/llvm-project/commit/1a2e77cf9e11dbf56b5720c607313a566eebb16e
 * changed inlining behavior and caused compilation failure as some branch
 * target distance exceeded 16bit representation which is the maximum for
 * cpu v1/v2/v3. Macro __BPF_CPU_VERSION__ is later implemented in clang18
 * to specify which cpu version is used for compilation. So a smaller
 * unroll_count can be set if __BPF_CPU_VERSION__ is less than 4, which
 * reduced some branch target distances and resolved the compilation failure.
 *
 * To capture the case where a developer/ci uses clang18 but the corresponding
 * repo checkpoint does not have __BPF_CPU_VERSION__, a smaller unroll_count
 * will be set as well to prevent potential compilation failures.
 */
#ifdef __BPF_CPU_VERSION__
#if __BPF_CPU_VERSION__ < 4
#define UNROLL_COUNT 90
#endif
#elif __clang_major__ == 18
#define UNROLL_COUNT 90
#endif

#include "pyperf.h"