From 298d6c14ca1936677aaf6cca3efc569b6e53d294 Mon Sep 17 00:00:00 2001 From: Reid Spencer Date: Fri, 17 Sep 2004 03:02:27 +0000 Subject: [PATCH] Make sure critical sections are entered before trying to leave them. Add some additional commentary about the workings of this module. Patch contributed by Jeff Cohen. Thanks Jeff! git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16383 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/System/Win32/Signals.cpp | 13 ++++++++++++- lib/System/Win32/Signals.inc | 13 ++++++++++++- 2 files changed, 24 insertions(+), 2 deletions(-) diff --git a/lib/System/Win32/Signals.cpp b/lib/System/Win32/Signals.cpp index d1bd2e84e04..130d3d63a18 100644 --- a/lib/System/Win32/Signals.cpp +++ b/lib/System/Win32/Signals.cpp @@ -28,6 +28,10 @@ static BOOL WINAPI LLVMConsoleCtrlHandler(DWORD dwCtrlType); static std::vector *FilesToRemove = NULL; static std::vector *DirectoriesToRemove = NULL; static bool RegisteredUnhandledExceptionFilter = false; + +// Windows creates a new thread to execute the console handler when an event +// (such as CTRL/C) occurs. This causes concurrency issues with the above +// globals which this critical section addresses. static CRITICAL_SECTION CriticalSection; namespace llvm { @@ -40,7 +44,10 @@ namespace llvm { static void RegisterHandler() { if (RegisteredUnhandledExceptionFilter) + { + EnterCriticalSection(&CriticalSection); return; + } // Now's the time to create the critical section. This is the first time // through here, and there's only one thread. @@ -205,9 +212,13 @@ static LONG WINAPI LLVMUnhandledExceptionFilter(LPEXCEPTION_POINTERS ep) { } static BOOL WINAPI LLVMConsoleCtrlHandler(DWORD dwCtrlType) { + // FIXME: This handler executes on a different thread. The main thread + // is still running, potentially creating new files to be cleaned up + // in the tiny window between the call to Cleanup() and process termination. + // Also, any files currently open cannot be deleted. Cleanup(); - // Allow normal processing to take place. + // Allow normal processing to take place; i.e., the process dies. return FALSE; } diff --git a/lib/System/Win32/Signals.inc b/lib/System/Win32/Signals.inc index d1bd2e84e04..130d3d63a18 100644 --- a/lib/System/Win32/Signals.inc +++ b/lib/System/Win32/Signals.inc @@ -28,6 +28,10 @@ static BOOL WINAPI LLVMConsoleCtrlHandler(DWORD dwCtrlType); static std::vector *FilesToRemove = NULL; static std::vector *DirectoriesToRemove = NULL; static bool RegisteredUnhandledExceptionFilter = false; + +// Windows creates a new thread to execute the console handler when an event +// (such as CTRL/C) occurs. This causes concurrency issues with the above +// globals which this critical section addresses. static CRITICAL_SECTION CriticalSection; namespace llvm { @@ -40,7 +44,10 @@ namespace llvm { static void RegisterHandler() { if (RegisteredUnhandledExceptionFilter) + { + EnterCriticalSection(&CriticalSection); return; + } // Now's the time to create the critical section. This is the first time // through here, and there's only one thread. @@ -205,9 +212,13 @@ static LONG WINAPI LLVMUnhandledExceptionFilter(LPEXCEPTION_POINTERS ep) { } static BOOL WINAPI LLVMConsoleCtrlHandler(DWORD dwCtrlType) { + // FIXME: This handler executes on a different thread. The main thread + // is still running, potentially creating new files to be cleaned up + // in the tiny window between the call to Cleanup() and process termination. + // Also, any files currently open cannot be deleted. Cleanup(); - // Allow normal processing to take place. + // Allow normal processing to take place; i.e., the process dies. return FALSE; }