xref: /aosp_15_r20/external/llvm-libc/src/assert/gpu/__assert_fail.cpp (revision 71db0c75aadcf003ffe3238005f61d7618a3fead)
1 //===-- GPU definition of a libc internal assert macro ----------*- C++ -*-===//
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 "src/assert/__assert_fail.h"
10 
11 #include "src/__support/CPP/atomic.h"
12 #include "src/__support/GPU/utils.h"
13 #include "src/__support/libc_assert.h"
14 #include "src/__support/macros/config.h"
15 #include "src/stdlib/abort.h"
16 
17 namespace LIBC_NAMESPACE_DECL {
18 
19 // A single-use lock to allow only a single thread to print the assertion.
20 static cpp::Atomic<uint32_t> lock = 0;
21 
22 LLVM_LIBC_FUNCTION(void, __assert_fail,
23                    (const char *assertion, const char *file, unsigned line,
24                     const char *function)) {
25   uint64_t mask = gpu::get_lane_mask();
26   // We only want a single work group or warp to handle the assertion. Each
27   // group attempts to claim the lock, if it is already claimed we simply exit.
28   uint32_t claimed = gpu::is_first_lane(mask)
29                          ? !lock.fetch_or(1, cpp::MemoryOrder::ACQUIRE)
30                          : 0;
31   if (!gpu::broadcast_value(mask, claimed))
32     gpu::end_program();
33 
34   // Only a single line should be printed if an assertion is hit.
35   if (gpu::is_first_lane(mask))
36     LIBC_NAMESPACE::report_assertion_failure(assertion, file, line, function);
37   gpu::sync_lane(mask);
38   LIBC_NAMESPACE::abort();
39 }
40 
41 } // namespace LIBC_NAMESPACE_DECL
42