lld/Common/Threads.cpp

//===- Threads.cpp --------------------------------------------------------===//
//
//                             The LLVM Linker
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#include "lld/Common/Threads.h"

bool lld::ThreadsEnabled = true;
Wait for all threads to terminate before exitting. I think it is not defined what would happen to detached threads when the main thread tries to exit. That means it was not guaranteed that unlinkAsync correctly removes a temporary file. It was also reported that this unlinkAsync caused a crash on Windows. This patch adds a few new functions so that the main thread always waits for non-main threads before exitting. I don't actually like the new two functions, runBackground and waitForBackgroundThreads, because it looks like it is a bit overdesigned. After all, what we are doing with these functions is to just remove a file. An alternative would be to do fork(2) and make the child process remove a file asynchronously. However, it has its own problems. Correctly forking and reclaiming a resource using waitpid(2) is not doable unless we know our process-wide settings (such as signal mask), but we can't make any assumption on it when lld is embedded to other process. So I chose to stick with threads instead of multi-processes. Differential Revision: https://reviews.llvm.org/D38571 llvm-svn: 315033 2017-10-05 23:01:11 +00:00			`//===- Threads.cpp --------------------------------------------------------===//`
			`//`
			`// The LLVM Linker`
			`//`
			`// This file is distributed under the University of Illinois Open Source`
			`// License. See LICENSE.TXT for details.`
			`//`
			`//===----------------------------------------------------------------------===//`

[lld] Move Threads to Common Summary: This will allow using the functionality from other linkers. It is also a prerequisite for sharing the error logging code. Reviewers: ruiu Reviewed By: ruiu Subscribers: emaste, mgorny, llvm-commits Differential Revision: https://reviews.llvm.org/D38822 llvm-svn: 315725 2017-10-13 18:22:55 +00:00			`#include "lld/Common/Threads.h"`
Wait for all threads to terminate before exitting. I think it is not defined what would happen to detached threads when the main thread tries to exit. That means it was not guaranteed that unlinkAsync correctly removes a temporary file. It was also reported that this unlinkAsync caused a crash on Windows. This patch adds a few new functions so that the main thread always waits for non-main threads before exitting. I don't actually like the new two functions, runBackground and waitForBackgroundThreads, because it looks like it is a bit overdesigned. After all, what we are doing with these functions is to just remove a file. An alternative would be to do fork(2) and make the child process remove a file asynchronously. However, it has its own problems. Correctly forking and reclaiming a resource using waitpid(2) is not doable unless we know our process-wide settings (such as signal mask), but we can't make any assumption on it when lld is embedded to other process. So I chose to stick with threads instead of multi-processes. Differential Revision: https://reviews.llvm.org/D38571 llvm-svn: 315033 2017-10-05 23:01:11 +00:00
[lld] Move Threads to Common Summary: This will allow using the functionality from other linkers. It is also a prerequisite for sharing the error logging code. Reviewers: ruiu Reviewed By: ruiu Subscribers: emaste, mgorny, llvm-commits Differential Revision: https://reviews.llvm.org/D38822 llvm-svn: 315725 2017-10-13 18:22:55 +00:00			`bool lld::ThreadsEnabled = true;`