1//===-- Implementation of crt for amdgpu ----------------------------------===//
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#include "config/gpu/app.h"
10#include "src/__support/GPU/utils.h"
11#include "src/__support/RPC/rpc_client.h"
12#include "src/__support/macros/config.h"
13#include "src/stdlib/atexit.h"
14#include "src/stdlib/exit.h"
15
16extern "C" int main(int argc, char **argv, char **envp);
17
18namespace LIBC_NAMESPACE_DECL {
19
20// FIXME: Factor this out into common logic so we don't need to stub it here.
21void teardown_main_tls() {}
22
23DataEnvironment app;
24
25extern "C" uintptr_t __init_array_start[];
26extern "C" uintptr_t __init_array_end[];
27extern "C" uintptr_t __fini_array_start[];
28extern "C" uintptr_t __fini_array_end[];
29
30using InitCallback = void(int, char **, char **);
31using FiniCallback = void(void);
32
33static void call_init_array_callbacks(int argc, char **argv, char **env) {
34 size_t init_array_size = __init_array_end - __init_array_start;
35 for (size_t i = 0; i < init_array_size; ++i)
36 reinterpret_cast<InitCallback *>(__init_array_start[i])(argc, argv, env);
37}
38
39static void call_fini_array_callbacks() {
40 size_t fini_array_size = __fini_array_end - __fini_array_start;
41 for (size_t i = fini_array_size; i > 0; --i)
42 reinterpret_cast<FiniCallback *>(__fini_array_start[i - 1])();
43}
44
45} // namespace LIBC_NAMESPACE_DECL
46
47extern "C" [[gnu::visibility("protected"), clang::amdgpu_kernel,
48 clang::amdgpu_flat_work_group_size(1, 1),
49 clang::amdgpu_max_num_work_groups(1)]] void
50_begin(int argc, char **argv, char **env) {
51 __atomic_store_n(&LIBC_NAMESPACE::app.env_ptr,
52 reinterpret_cast<uintptr_t *>(env), __ATOMIC_RELAXED);
53 // We want the fini array callbacks to be run after other atexit
54 // callbacks are run. So, we register them before running the init
55 // array callbacks as they can potentially register their own atexit
56 // callbacks.
57 LIBC_NAMESPACE::atexit(&LIBC_NAMESPACE::call_fini_array_callbacks);
58 LIBC_NAMESPACE::call_init_array_callbacks(argc, argv, env);
59}
60
61extern "C" [[gnu::visibility("protected"), clang::amdgpu_kernel]] void
62_start(int argc, char **argv, char **envp, int *ret) {
63 // Invoke the 'main' function with every active thread that the user launched
64 // the _start kernel with.
65 __atomic_fetch_or(ret, main(argc, argv, envp), __ATOMIC_RELAXED);
66}
67
68extern "C" [[gnu::visibility("protected"), clang::amdgpu_kernel,
69 clang::amdgpu_flat_work_group_size(1, 1),
70 clang::amdgpu_max_num_work_groups(1)]] void
71_end(int retval) {
72 // Only a single thread should call `exit` here, the rest should gracefully
73 // return from the kernel. This is so only one thread calls the destructors
74 // registred with 'atexit' above.
75 LIBC_NAMESPACE::exit(retval);
76}
77

source code of libc/startup/gpu/amdgpu/start.cpp