refactor: use function-local statics for platform accessors to dodge SIOF

targets/platform/fs/fs.h

@@ -1,3 +1,18 @@
+#pragma once
+
 #include "IPlatformFilesystem.h"
 
-extern IPlatformFilesystem& PlatformFilesystem;
+// Function accessor backed by a function-local static (Meyers singleton).
+// Avoids the static-initialization-order fiasco that the previous
+// `extern IPlatformFilesystem& PlatformFilesystem;` form had: anything reading PlatformFilesystem
+// during another translation unit's static init was UB.
+//
+// The macro lets the existing call sites keep writing `PlatformFilesystem.foo()`
+// without each call site having to add the `()`. The expansion is just
+// a call to a function returning a reference, so codegen is unchanged
+// once inlined.
+namespace platform_internal {
+IPlatformFilesystem& PlatformFilesystem_get();
+}
+
+#define PlatformFilesystem (::platform_internal::PlatformFilesystem_get())

targets/platform/fs/std/StdFilesystem.cpp

@@ -6,8 +6,12 @@
 #include <unistd.h>
 #endif
 
-StdFilesystem std_filesystem_instance;
-IPlatformFilesystem& PlatformFilesystem = std_filesystem_instance;
+namespace platform_internal {
+IPlatformFilesystem& PlatformFilesystem_get() {
+    static StdFilesystem instance;
+    return instance;
+}
+}
 
 IPlatformFilesystem::ReadResult StdFilesystem::readFile(const std::filesystem::path& path,
                                    void* buffer, std::size_t capacity) {

targets/platform/input/input.h

@@ -1,3 +1,18 @@
+#pragma once
+
 #include "IPlatformInput.h"
 
-extern IPlatformInput& PlatformInput;
+// Function accessor backed by a function-local static (Meyers singleton).
+// Avoids the static-initialization-order fiasco that the previous
+// `extern IPlatformInput& PlatformInput;` form had: anything reading PlatformInput
+// during another translation unit's static init was UB.
+//
+// The macro lets the existing call sites keep writing `PlatformInput.foo()`
+// without each call site having to add the `()`. The expansion is just
+// a call to a function returning a reference, so codegen is unchanged
+// once inlined.
+namespace platform_internal {
+IPlatformInput& PlatformInput_get();
+}
+
+#define PlatformInput (::platform_internal::PlatformInput_get())

targets/platform/input/sdl2/SDL2Input.cpp

@@ -20,8 +20,12 @@
 #include "../InputConstants.h"
 #include "../../PlatformTypes.h"
 
-SDL2Input sdl2_input_instance;
-IPlatformInput& PlatformInput = sdl2_input_instance;
+namespace platform_internal {
+IPlatformInput& PlatformInput_get() {
+    static SDL2Input instance;
+    return instance;
+}
+}
 
 static const int KEY_COUNT = SDL_NUM_SCANCODES;
 static const int BTN_COUNT = SDL_CONTROLLER_BUTTON_MAX;

targets/platform/profile/profile.h

@@ -1,4 +1,18 @@
-#include "IPlatformProfile.h"
-#include "ProfileConstants.h"
+#pragma once
 
-extern IPlatformProfile& PlatformProfile;
+#include "IPlatformProfile.h"
+
+// Function accessor backed by a function-local static (Meyers singleton).
+// Avoids the static-initialization-order fiasco that the previous
+// `extern IPlatformProfile& PlatformProfile;` form had: anything reading PlatformProfile
+// during another translation unit's static init was UB.
+//
+// The macro lets the existing call sites keep writing `PlatformProfile.foo()`
+// without each call site having to add the `()`. The expansion is just
+// a call to a function returning a reference, so codegen is unchanged
+// once inlined.
+namespace platform_internal {
+IPlatformProfile& PlatformProfile_get();
+}
+
+#define PlatformProfile (::platform_internal::PlatformProfile_get())

targets/platform/profile/stub/StubProfile.cpp

@@ -7,8 +7,12 @@
 #include "../ProfileConstants.h"
 #include "input/input.h"
 
-StubProfile stub_profile_instance;
-IPlatformProfile& PlatformProfile = stub_profile_instance;
+namespace platform_internal {
+IPlatformProfile& PlatformProfile_get() {
+    static StubProfile instance;
+    return instance;
+}
+}
 
 namespace {
 constexpr PlayerUID kFakeXuidBase = 0xe000d45248242f2eULL;

targets/platform/renderer/gl/GLRenderer.cpp

@@ -1,5 +1,6 @@
 #include "GLRenderer.h"
 
+#include "renderer/renderer.h"
 #include "PlatformTypes.h"
 #include "SDL.h"
 #include "SDL_error.h"
@@ -54,8 +55,12 @@
 #include <utility>
 #include <vector>
 
-GLRenderer gl_renderer_instance;
-IPlatformRenderer& PlatformRenderer = gl_renderer_instance;
+namespace platform_internal {
+IPlatformRenderer& PlatformRenderer_get() {
+    static GLRenderer instance;
+    return instance;
+}
+}
 
 // MARK: Shaders
 

targets/platform/renderer/renderer.h

@@ -2,9 +2,17 @@
 
 #include "IPlatformRenderer.h"
 
-// Defined in the linked renderer backend (currently
-// platform/renderer/gl/GLRenderer.cpp). The legacy gl* macro shim used
-// by older rendering call sites lives in
-// platform/renderer/gl/gl_compat.h, which is brought in via
-// platform/stubs.h on linux.
-extern IPlatformRenderer& PlatformRenderer;
+// Function accessor backed by a function-local static (Meyers singleton).
+// Avoids the static-initialization-order fiasco that the previous
+// `extern IPlatformRenderer& PlatformRenderer;` form had: anything reading PlatformRenderer
+// during another translation unit's static init was UB.
+//
+// The macro lets the existing call sites keep writing `PlatformRenderer.foo()`
+// without each call site having to add the `()`. The expansion is just
+// a call to a function returning a reference, so codegen is unchanged
+// once inlined.
+namespace platform_internal {
+IPlatformRenderer& PlatformRenderer_get();
+}
+
+#define PlatformRenderer (::platform_internal::PlatformRenderer_get())

targets/platform/storage/storage.h

@@ -1,3 +1,18 @@
+#pragma once
+
 #include "IPlatformStorage.h"
 
-extern IPlatformStorage& PlatformStorage;
+// Function accessor backed by a function-local static (Meyers singleton).
+// Avoids the static-initialization-order fiasco that the previous
+// `extern IPlatformStorage& PlatformStorage;` form had: anything reading PlatformStorage
+// during another translation unit's static init was UB.
+//
+// The macro lets the existing call sites keep writing `PlatformStorage.foo()`
+// without each call site having to add the `()`. The expansion is just
+// a call to a function returning a reference, so codegen is unchanged
+// once inlined.
+namespace platform_internal {
+IPlatformStorage& PlatformStorage_get();
+}
+
+#define PlatformStorage (::platform_internal::PlatformStorage_get())

targets/platform/storage/stub/StubStorage.cpp

@@ -6,8 +6,12 @@
 #include <string>
 #include <vector>
 
-StubStorage stub_storage_instance;
-IPlatformStorage& PlatformStorage = stub_storage_instance;
+namespace platform_internal {
+IPlatformStorage& PlatformStorage_get() {
+    static StubStorage instance;
+    return instance;
+}
+}
 
 static XMARKETPLACE_CONTENTOFFER_INFO s_dummyOffer = {};
 static XCONTENT_DATA s_dummyContentData = {};