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//===--- ThreadCrashReporter.cpp - Thread local signal handling --*- C++-*-===//
//
// 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 "support/ThreadCrashReporter.h"
#include "llvm/Support/Signals.h"
#include "llvm/Support/ThreadLocal.h"
#include <atomic>
namespace clang {
namespace clangd {
static thread_local ThreadCrashReporter *CurrentReporter = nullptr;
void ThreadCrashReporter::runCrashHandlers() {
// No signal handling is done here on top of what AddSignalHandler() does:
// on Windows the signal handling is implmented via
// SetUnhandledExceptionFilter() which is thread-directed, and on Unix
// platforms the handlers are only called for KillSigs out of which only
// SIGQUIT seems to be process-directed and would be delivered to any thread
// that is not blocking it, but if the thread it gets delivered to has a
// ThreadCrashReporter installed during the interrupt — it seems reasonable to
// let it run and print the thread's context information.
// Call the reporters in LIFO order.
ThreadCrashReporter *Reporter = CurrentReporter;
while (Reporter) {
Reporter->Callback();
Reporter = Reporter->Next;
}
}
ThreadCrashReporter::ThreadCrashReporter(SignalCallback ThreadLocalCallback)
: Callback(std::move(ThreadLocalCallback)), Next(nullptr) {
this->Next = CurrentReporter;
CurrentReporter = this;
// Don't reorder subsequent operations: whatever comes after might crash and
// we want the the crash handler to see the reporter values we just set.
std::atomic_signal_fence(std::memory_order_seq_cst);
}
ThreadCrashReporter::~ThreadCrashReporter() {
assert(CurrentReporter == this);
CurrentReporter = this->Next;
// Don't reorder subsequent operations: whatever comes after might crash and
// we want the the crash handler to see the reporter values we just set.
std::atomic_signal_fence(std::memory_order_seq_cst);
}
} // namespace clangd
} // namespace clang
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