GLES2: Use require_constant_initialization for g_Mutex

A static assert to verify that the global mutex g_Mutex is trivially constructed fails to compile with clang when using the STL shipped with Visual Studio 2019. Use __attribute__((require_constant_initialization)) instead to verify for constant initialization. BUG=angleproject:3936 Change-Id: I5969762ad5a99033143513d7c4992344da276b1a Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1832164Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org> Commit-Queue: Geoff Lang <geofflang@chromium.org>

GLES2: Use require_constant_initialization for g_Mutex
755417dd · Jaime Bernardo · Commit Bot · 4a276034 · 755417dd · 755417dd
Commit 755417dd authored Sep 30, 2019 by Jaime Bernardo Committed by Commit Bot Oct 01, 2019
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Showing with 9 additions and 3 deletions

AUTHORS AUTHORS +1 -0

angleutils.h src/common/angleutils.h +6 -0

global_state.cpp src/libGLESv2/global_state.cpp +2 -3

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--- a/AUTHORS
+++ b/AUTHORS
@@ -58,3 +58,4 @@ Jérôme Duval
 Thomas Miller
 Till Rathmann
 Nick Shaforostov
+Jaime Bernardo
--- a/src/common/angleutils.h
+++ b/src/common/angleutils.h
@@ -345,4 +345,10 @@ std::string ToString(const T &value)
 #    define ANGLE_MAYBE_UNUSED
 #endif  // __has_cpp_attribute(maybe_unused)

+#if __has_cpp_attribute(require_constant_initialization)
+#    define ANGLE_REQUIRE_CONSTANT_INIT [[require_constant_initialization]]
+#else
+#    define ANGLE_REQUIRE_CONSTANT_INIT
+#endif  // __has_cpp_attribute(require_constant_initialization)
+
 #endif  // COMMON_ANGLEUTILS_H_
--- a/src/libGLESv2/global_state.cpp
+++ b/src/libGLESv2/global_state.cpp
@@ -35,9 +35,8 @@ namespace
 {
 static TLSIndex threadTLS = TLS_INVALID_INDEX;
 Debug *g_Debug            = nullptr;
-std::atomic<std::mutex *> g_Mutex;
-static_assert(std::is_trivially_constructible<decltype(g_Mutex)>::value,
-              "global mutex is not trivially constructible");
+
+ANGLE_REQUIRE_CONSTANT_INIT std::atomic<std::mutex *> g_Mutex(nullptr);
 static_assert(std::is_trivially_destructible<decltype(g_Mutex)>::value,
              "global mutex is not trivially destructible");