Commit 884a65af authored by Russell Gallop's avatar Russell Gallop
Browse files

[Support] Replace Windows __declspec(thread) with thread_local for LLVM_THREAD_LOCAL 

Windows minimum host tools version is now VS2017, which supports C++11
thread_local so use this for LLVM_THREAD_LOCAL instead of
declspec(thread). According to [1], thread_local is implemented with
declspec(thread) so this should be NFC.

[1] https://docs.microsoft.com/en-us/cpp/cpp/thread?view=vs-2017

Differential Revision: https://reviews.llvm.org/D72399
parent 93a4dede

llvm/include/llvm/Support/Compiler.h

+7 −11
Original line number Diff line number Diff line
@@ -512,19 +512,15 @@ void AnnotateIgnoreWritesEnd(const char *file, int line); 
/// extern globals, and static globals.

///

/// This is essentially an extremely restricted analog to C++11's thread_local

/// support, and uses that when available. However, it falls back on

/// platform-specific or vendor-provided extensions when necessary. These

/// extensions don't support many of the C++11 thread_local's features. You

/// should only use this for PODs that you can statically initialize to

/// some constant value. In almost all circumstances this is most appropriate

/// for use with a pointer, integer, or small aggregation of pointers and

/// integers.

/// support. It uses thread_local if available, falling back on gcc __thread

/// if not. __thread doesn't support many of the C++11 thread_local's

/// features. You should only use this for PODs that you can statically

/// initialize to some constant value. In almost all circumstances this is most

/// appropriate for use with a pointer, integer, or small aggregation of

/// pointers and integers.

#if LLVM_ENABLE_THREADS

#if __has_feature(cxx_thread_local)

#if __has_feature(cxx_thread_local) || defined(_MSC_VER)

#define LLVM_THREAD_LOCAL thread_local

#elif defined(_MSC_VER)

// MSVC supports this with a __declspec.

#define LLVM_THREAD_LOCAL __declspec(thread)

#else

// Clang, GCC, and other compatible compilers used __thread prior to C++11 and

// we only need the restricted functionality that provides.