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//===-- Implementation of crt for nvptx -----------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "src/__support/GPU/utils.h"
#include "src/__support/RPC/rpc_client.h"
#include "src/stdlib/atexit.h"
#include "src/stdlib/exit.h"
extern "C" int main(int argc, char **argv, char **envp);
namespace __llvm_libc {
static cpp::Atomic<uint32_t> lock = 0;
extern "C" {
// Nvidia's 'nvlink' linker does not provide these symbols. We instead need
// to manually create them and update the globals in the loader implememtation.
uintptr_t *__init_array_start [[gnu::visibility("protected")]];
uintptr_t *__init_array_end [[gnu::visibility("protected")]];
uintptr_t *__fini_array_start [[gnu::visibility("protected")]];
uintptr_t *__fini_array_end [[gnu::visibility("protected")]];
}
using InitCallback = void(int, char **, char **);
using FiniCallback = void(void);
static void call_init_array_callbacks(int argc, char **argv, char **env) {
size_t init_array_size = __init_array_end - __init_array_start;
for (size_t i = 0; i < init_array_size; ++i)
reinterpret_cast<InitCallback *>(__init_array_start[i])(argc, argv, env);
}
static void call_fini_array_callbacks() {
size_t fini_array_size = __fini_array_end - __fini_array_start;
for (size_t i = 0; i < fini_array_size; ++i)
reinterpret_cast<FiniCallback *>(__fini_array_start[i])();
}
} // namespace __llvm_libc
extern "C" [[gnu::visibility("protected"), clang::nvptx_kernel]] void
_begin(int argc, char **argv, char **env, void *in, void *out, void *buffer) {
// We need to set up the RPC client first in case any of the constructors
// require it.
__llvm_libc::rpc::client.reset(__llvm_libc::gpu::get_lane_size(),
&__llvm_libc::lock, in, out, buffer);
// We want the fini array callbacks to be run after other atexit
// callbacks are run. So, we register them before running the init
// array callbacks as they can potentially register their own atexit
// callbacks.
__llvm_libc::atexit(&__llvm_libc::call_fini_array_callbacks);
__llvm_libc::call_init_array_callbacks(argc, argv, env);
}
extern "C" [[gnu::visibility("protected"), clang::nvptx_kernel]] void
_start(int argc, char **argv, char **envp, int *ret) {
// Invoke the 'main' function with every active thread that the user launched
// the _start kernel with.
__atomic_fetch_or(ret, main(argc, argv, envp), __ATOMIC_RELAXED);
}
extern "C" [[gnu::visibility("protected"), clang::nvptx_kernel]] void
_end(int retval) {
// To finis the execution we invoke all the callbacks registered via 'atexit'
// and then exit with the appropriate return value.
__llvm_libc::exit(retval);
}
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