| 1 | //===--- ThreadCrashReporter.cpp - Thread local signal handling --*- C++-*-===// |
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| 2 | // |
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| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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| 4 | // See https://llvm.org/LICENSE.txt for license information. |
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| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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| 6 | // |
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| 7 | //===----------------------------------------------------------------------===// |
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| 8 | |
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| 9 | #include "support/ThreadCrashReporter.h" |
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| 10 | #include <atomic> |
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| 11 | |
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| 12 | namespace clang { |
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| 13 | namespace clangd { |
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| 14 | |
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| 15 | static thread_local ThreadCrashReporter *CurrentReporter = nullptr; |
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| 16 | |
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| 17 | void ThreadCrashReporter::runCrashHandlers() { |
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| 18 | // No signal handling is done here on top of what AddSignalHandler() does: |
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| 19 | // on Windows the signal handling is implmented via |
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| 20 | // SetUnhandledExceptionFilter() which is thread-directed, and on Unix |
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| 21 | // platforms the handlers are only called for KillSigs out of which only |
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| 22 | // SIGQUIT seems to be process-directed and would be delivered to any thread |
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| 23 | // that is not blocking it, but if the thread it gets delivered to has a |
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| 24 | // ThreadCrashReporter installed during the interrupt — it seems reasonable to |
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| 25 | // let it run and print the thread's context information. |
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| 26 | |
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| 27 | // Call the reporters in LIFO order. |
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| 28 | ThreadCrashReporter *Reporter = CurrentReporter; |
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| 29 | while (Reporter) { |
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| 30 | Reporter->Callback(); |
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| 31 | Reporter = Reporter->Next; |
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| 32 | } |
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| 33 | } |
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| 34 | |
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| 35 | ThreadCrashReporter::ThreadCrashReporter(SignalCallback ThreadLocalCallback) |
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| 36 | : Callback(std::move(ThreadLocalCallback)), Next(nullptr) { |
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| 37 | this->Next = CurrentReporter; |
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| 38 | CurrentReporter = this; |
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| 39 | // Don't reorder subsequent operations: whatever comes after might crash and |
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| 40 | // we want the crash handler to see the reporter values we just set. |
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| 41 | std::atomic_signal_fence(m: std::memory_order_seq_cst); |
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| 42 | } |
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| 43 | |
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| 44 | ThreadCrashReporter::~ThreadCrashReporter() { |
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| 45 | assert(CurrentReporter == this); |
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| 46 | CurrentReporter = this->Next; |
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| 47 | // Don't reorder subsequent operations: whatever comes after might crash and |
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| 48 | // we want the crash handler to see the reporter values we just set. |
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| 49 | std::atomic_signal_fence(m: std::memory_order_seq_cst); |
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| 50 | } |
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| 51 | |
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| 52 | } // namespace clangd |
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| 53 | } // namespace clang |
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| 54 | |
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