[llvm] 129311a - [libSupport] make CallBacksToRun static local

[Mehdi Amini via llvm-commits]

Author: Tal Kedar
Date: 2022-03-19T20:31:04Z
New Revision: 129311ac0bbbea78d980cb44565c0daeab924511

URL: https://github.com/llvm/llvm-project/commit/129311ac0bbbea78d980cb44565c0daeab924511
DIFF: https://github.com/llvm/llvm-project/commit/129311ac0bbbea78d980cb44565c0daeab924511.diff

LOG: [libSupport] make CallBacksToRun static local

In order to allow compiling with -Werror=global-constructors with c++20 and above.

Discussion: https://discourse.llvm.org/t/llvm-lib-support-signals-cpp-fails-to-compile-due-to-werror-global-constructors/61070

Reviewed By: mehdi_amini

Differential Revision: https://reviews.llvm.org/D122067

Added: 
    

Modified: 
    llvm/lib/Support/Signals.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Support/Signals.cpp b/llvm/lib/Support/Signals.cpp
index f10551df4baa5..a6fd845da8690 100644
--- a/llvm/lib/Support/Signals.cpp
+++ b/llvm/lib/Support/Signals.cpp
@@ -29,6 +29,7 @@
 #include "llvm/Support/Program.h"
 #include "llvm/Support/StringSaver.h"
 #include "llvm/Support/raw_ostream.h"
+#include <array>
 #include <vector>
 
 //===----------------------------------------------------------------------===//
@@ -80,12 +81,20 @@ struct CallbackAndCookie {
   enum class Status { Empty, Initializing, Initialized, Executing };
   std::atomic<Status> Flag;
 };
+
 static constexpr size_t MaxSignalHandlerCallbacks = 8;
-static CallbackAndCookie CallBacksToRun[MaxSignalHandlerCallbacks];
+
+// A global array of CallbackAndCookie may not compile with
+// -Werror=global-constructors in c++20 and above
+static std::array<CallbackAndCookie, MaxSignalHandlerCallbacks> &
+CallBacksToRun() {
+  static std::array<CallbackAndCookie, MaxSignalHandlerCallbacks> callbacks;
+  return callbacks;
+}
 
 // Signal-safe.
 void sys::RunSignalHandlers() {
-  for (CallbackAndCookie &RunMe : CallBacksToRun) {
+  for (CallbackAndCookie &RunMe : CallBacksToRun()) {
     auto Expected = CallbackAndCookie::Status::Initialized;
     auto Desired = CallbackAndCookie::Status::Executing;
     if (!RunMe.Flag.compare_exchange_strong(Expected, Desired))
@@ -100,7 +109,7 @@ void sys::RunSignalHandlers() {
 // Signal-safe.
 static void insertSignalHandler(sys::SignalHandlerCallback FnPtr,
                                 void *Cookie) {
-  for (CallbackAndCookie &SetMe : CallBacksToRun) {
+  for (CallbackAndCookie &SetMe : CallBacksToRun()) {
     auto Expected = CallbackAndCookie::Status::Empty;
     auto Desired = CallbackAndCookie::Status::Initializing;
     if (!SetMe.Flag.compare_exchange_strong(Expected, Desired))