Fix visionOS build errors and warnings where possible.

- Remove visionOS from multi-platform builds because it
  requires Xcode 15+ and will abort a multi-platform build.
- Define TARGET_OS_XR for older SDK's.
- A number of SDK deprecation warnings remain when building for visionOS.
  These cannot be removed without significant refactoring.
- Build visionOS dependencies for Release build by default.
- Fix local variable initialization warning (unrelated).

Common/MVKCommonEnvironment.h

@@ -63,6 +63,9 @@ extern "C" {
 #endif
 
 /** Building for visionOS. */
+#ifndef TARGET_OS_XR
+#	define TARGET_OS_XR				0		// Older SDK's don't define TARGET_OS_XR
+#endif
 #ifndef MVK_VISIONOS
 #	define MVK_VISIONOS				TARGET_OS_XR
 #endif

Docs/Whats_New.md

@@ -26,6 +26,7 @@ Released TBD
 	- `VK_EXT_shader_subgroup_ballot`
 	- `VK_EXT_shader_subgroup_vote`
 - Add support for `VK_PRIMITIVE_TOPOLOGY_TRIANGLE_FAN`.
+- Support building MoltenVK for visionOS.
 - Ensure non-dispatch compute commands don't interfere with compute encoding state used by dispatch commands.
 - Support `VK_PRESENT_MODE_IMMEDIATE_KHR` if `VkPresentTimeGOOGLE::desiredPresentTime` is zero.
 - Support maximizing the concurrent executing compilation tasks via `MVKConfiguration::shouldMaximizeConcurrentCompilation`

ExternalDependencies.xcodeproj/xcshareddata/xcschemes/ExternalDependencies-xrOS.xcscheme

@@ -30,7 +30,7 @@
       shouldAutocreateTestPlan = "YES">
    </TestAction>
    <LaunchAction
-      buildConfiguration = "Debug"
+      buildConfiguration = "Release"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
       launchStyle = "0"

Makefile

@@ -21,6 +21,8 @@ MAKEARGS := $(strip \
       $(v)=$(value $(v)) ,)))
 
 # Specify individually (not as dependencies) so the sub-targets don't run in parallel
+# visionos and visionossim are currently excluded from `all` because they require
+# Xcode 15+ and will abort a multi-platform build on earlier Xcode versions.
 .PHONY: all
 all:
 	@$(MAKE) macos
@@ -29,8 +31,8 @@ all:
 	@$(MAKE) maccat
 	@$(MAKE) tvos
 	@$(MAKE) tvossim
-	@$(MAKE) visionos
-	@$(MAKE) visionossim
+#	@$(MAKE) visionos       # Requires Xcode 15+
+#	@$(MAKE) visionossim    # Requires Xcode 15+
 
 .PHONY: all-debug
 all-debug:
@@ -40,8 +42,8 @@ all-debug:
 	@$(MAKE) maccat-debug
 	@$(MAKE) tvos-debug
 	@$(MAKE) tvossim-debug
-	@$(MAKE) visionos-debug
-	@$(MAKE) visionossim-debug
+#	@$(MAKE) visionos-debug       # Requires Xcode 15+
+#	@$(MAKE) visionossim-debug    # Requires Xcode 15+
 
 .PHONY: macos
 macos:

MoltenVK/MoltenVK/GPUObjects/MVKPipeline.mm

@@ -1993,7 +1993,7 @@ static MTLVertexFormat mvkAdjustFormatVectorToSize(MTLVertexFormat format, uint3
 	// We'll set the VALID bit on the stage feedback when we compile it.
 	VkPipelineCreationFeedback* pPipelineFB = nullptr;
 	VkPipelineCreationFeedback* pStageFB = nullptr;
-	uint64_t pipelineStart;
+	uint64_t pipelineStart = 0;
 	if (pFeedbackInfo) {
 		pPipelineFB = pFeedbackInfo->pPipelineCreationFeedback;
 		// n.b. Do *NOT* use mvkClear().

README.md

@@ -19,7 +19,7 @@ Table of Contents
 -----------------
 
 - [Introduction to **MoltenVK**](#intro)
-- [Developing Vulkan Applications on *macOS, iOS, and tvOS*](#developing_vulkan)
+- [Developing Vulkan Applications on *macOS, iOS, tvOS, and visionOS*](#developing_vulkan)
 	- [Using the *Vulkan SDK*](#sdk)
 	- [Using MoltenVK Directly](#download)
 - [Fetching **MoltenVK** Source Code](#install)
@@ -38,19 +38,20 @@ Introduction to MoltenVK
 
 **MoltenVK** is a layered implementation of [*Vulkan 1.2*](https://www.khronos.org/vulkan) 
 graphics and compute functionality, that is built on Apple's [*Metal*](https://developer.apple.com/metal) 
-graphics and compute framework on *macOS*, *iOS*, and *tvOS*. **MoltenVK** allows you to use *Vulkan* 
-graphics and compute functionality to develop modern, cross-platform, high-performance graphical 
-games and applications, and to run them across many platforms, including *macOS*, *iOS*, *tvOS*,
-*Simulators*, and *Mac Catalyst* on *macOS 11.0+*, and all *Apple* architectures, including *Apple Silicon*.
+graphics and compute framework on *macOS*, *iOS*, *tvOS*, and *visionOS*. **MoltenVK** allows 
+you to use *Vulkan* graphics and compute functionality to develop modern, cross-platform, 
+high-performance graphical games and applications, and to run them across many platforms, 
+including *macOS*, *iOS*, *tvOS*, *visionOS*, *Simulators*, and *Mac Catalyst* on *macOS 11.0+*, 
+and all *Apple* architectures, including *Apple Silicon*.
 
 *Metal* uses a different shading language, the *Metal Shading Language (MSL)*, than 
 *Vulkan*, which uses *SPIR-V*. **MoltenVK** automatically converts your *SPIR-V* shaders 
 to their *MSL* equivalents.
 
-To provide *Vulkan* capability to the *macOS*, *iOS*, and *tvOS* platforms, **MoltenVK** uses *Apple's* 
-publicly available API's, including *Metal*. **MoltenVK** does **_not_** use any private or
-undocumented API calls or features, so your app will be compatible with all standard distribution 
-channels, including *Apple's App Store*.
+To provide *Vulkan* capability to the *macOS*, *iOS*, *tvOS*, and *visionOS* platforms, 
+**MoltenVK** uses *Apple's* publicly available API's, including *Metal*. **MoltenVK** 
+does **_not_** use any private or undocumented API calls or features, so your app will 
+be compatible with all standard distribution channels, including *Apple's App Store*.
 
 The **MoltenVK** runtime package contains two products:
 
@@ -67,8 +68,8 @@ The **MoltenVK** runtime package contains two products:
 
 
 <a name="developing_vulkan"></a>
-Developing *Vulkan* Applications for *macOS, iOS, and tvOS*
----------------------------------------------------------
+Developing *Vulkan* Applications for *macOS, iOS, tvOS, and visionOS*
+---------------------------------------------------------------------
 
 <a name="sdk"></a>
 ### Using the *Vulkan SDK*
@@ -96,10 +97,10 @@ extension in the *Vulkan* specification for more information about the use of th
 <a name="download"></a>
 ### Using MoltenVK Directly
 
-If you are developing a *Vulkan* application for *iOS* or *tvOS*, or are developing a
-*Vulkan* application for *macOS* and want to use a different version or build of the
-**MoltenVK** runtime library than provided in the *macOS Vulkan SDK*, you can access
-a pre-built MoltenVK binary library from the **MoltenVK** repository, by
+If you are developing a *Vulkan* application for *iOS*, *tvOS*, or *visionOS*, or are 
+developing a *Vulkan* application for *macOS* and want to use a different version or 
+build of the **MoltenVK** runtime library than provided in the *macOS Vulkan SDK*, 
+you can access a pre-built MoltenVK binary library from the **MoltenVK** repository, by
 [selecting a repository commit from the list](https://github.com/KhronosGroup/MoltenVK/actions),
 and downloading the associated **MoltenVK** runtime library artifact.
 
@@ -148,14 +149,21 @@ for which to build the external libraries. The platform choices include:
 	--maccat 
 	--tvos 
 	--tvossim
+	--visionos 
+	--visionossim
+
+The `visionos` and `visionossim` selections require Xcode 15+.
 
 You can specify multiple of these selections. The result is a single `XCFramework` 
 for each external dependency library, with each `XCFramework` containing binaries for 
 each of the requested platforms. 
 
-The `--all` selection is the same as entering all of the other platform choices,
-and will result in a single `XCFramework` for each external dependency library, 
-with each `XCFramework` containing binaries for all supported platforms and simulators.
+The `--all` selection is the same as entering all of the other platform choices, except 
+`--visionos` and `--visionossim`, and will result in a single `XCFramework` for each 
+external dependency library, with each `XCFramework` containing binaries for all supported 
+platforms and simulators. The `--visionos` and `--visionossim` selections must be invoked
+with a separate invocation of `fetchDependencies`, because those selections require 
+Xcode 15+, and will cause a multi-platform build on older versions of Xcode to abort.
 
 Running `fetchDependencies` repeatedly with different platforms will accumulate 
 targets in the `XCFramework`.
@@ -196,11 +204,11 @@ _Xcode_ version. If you require support for earlier OS versions, modify the `MAC
 build setting of `iOS 11.0` or greater, or a minimum **tvOS Deployment Target** (aka `TVOS_DEPLOYMENT_TARGET `) 
 build setting of `tvOS 11.0` or greater.
 
-Once built, the **MoltenVK** libraries can be run on *macOS*, *iOS* or *tvOS* devices that support *Metal*,
-or on the *Xcode* *iOS Simulator* or *tvOS Simulator*.
+Once built, the **MoltenVK** libraries can be run on *macOS*, *iOS*, *tvOS*, or *visionOS* devices 
+that support *Metal*,or on the *Xcode* *iOS Simulator*, *tvOS Simulator*, or *visionOS Simulator*.
 
-- At runtime, **MoltenVK** requires at least *macOS 10.11*, *iOS 9*, or *tvOS 9* 
-  (or *iOS 11* or *tvOS 11* if using `IOSurfaces`).
+- At runtime, **MoltenVK** requires at least *macOS 10.11*, *iOS 9.0*, *tvOS 9.0*, 
+  or *visionOS 1.0* (or *iOS 11* or *tvOS 11* if using `IOSurfaces`).
 - Information on *macOS* devices that are compatible with *Metal* can be found in 
   [this article](http://www.idownloadblog.com/2015/06/22/how-to-find-mac-el-capitan-metal-compatible).
 - Information on *iOS* devices that are compatible with *Metal* can be found in 
@@ -220,6 +228,7 @@ platforms, or just one platform (in **_Release_** configuration):
 - **MoltenVK Package (macOS only)** 
 - **MoltenVK Package (iOS only)**
 - **MoltenVK Package (tvOS only)**
+- **MoltenVK Package (visionOS only)**  _(requires Xcode 15+)_
 
 Each of these`MoltenVKPackaging.xcodeproj` *Xcode* project *Schemes* puts the resulting packages in the 
 `Package` directory, creating it if necessary. This directory contains separate `Release` and `Debug` 
@@ -254,6 +263,8 @@ from the command line. The following `make` targets are provided:
 	make maccat
 	make tvos
 	make tvossim
+	make visionos
+	make visionossim
 
 	make all-debug
 	make macos-debug
@@ -262,12 +273,15 @@ from the command line. The following `make` targets are provided:
 	make maccat-debug
 	make tvos-debug
 	make tvossim-debug
+	make visionos-debug
+	make visionossim-debug
 
 	make clean
 	make install
 
 - Running `make` repeatedly with different targets will accumulate binaries for these different targets.
-- The `all` target executes all platform targets.
+- The `all` target executes all platform targets, except `visionos` and `visionossim`, as these require
+  Xcode 15+, and will abort a multi-platform build on older versions of Xcode.
 - The `all` target is the default target. Running `make` with no arguments is the same as running `make all`.
 - The `*-debug` targets build the binaries using the **_Debug_** configuration.
 - The `install` target will copy the most recently built `MoltenVK.xcframework` into the 
@@ -346,14 +360,14 @@ the contents of that directory out of this **MoltenVK** repository into your own
 ------------------------------------
 
 **MoltenVK** is designed to be an implementation of a *Vulkan 1.2* subset that runs on *macOS*, *iOS*, 
-and *tvOS* platforms by mapping *Vulkan* capability to native *Metal* capability.
+*tvOS*, and *visionOS* platforms by mapping *Vulkan* capability to native *Metal* capability.
 
 The fundamental design and development goal of **MoltenVK** is to provide this capability in a way that 
 is both maximally compliant with the *Vulkan 1.2* specification, and maximally  performant.
 
-Such compliance and performance is inherently affected by the capability available through *Metal*, as the 
-native graphics driver on *macOS*, *iOS*, and *tvOS* platforms. *Vulkan* compliance may fall into one of 
-the following categories:
+Such compliance and performance is inherently affected by the capability available through *Metal*, 
+as the native graphics driver on *macOS*, *iOS*, *tvOS*, and *visionOS* platforms. *Vulkan* 
+compliance may fall into one of the following categories:
 
 - Direct mapping between *Vulkan* capabilities and *Metal* capabilities. Within **MoltenVK**, the vast
   majority of *Vulkan* capability is the result of this type of direct mapping. 
@@ -376,7 +390,7 @@ be implemented or worked around.
 [*Khronos Vulkan Portability Initiative*](https://www.khronos.org/vulkan/portability-initiative), 
 whose intention is to provide specifications, resources, and tools to allow developers to understand and design 
 their *Vulkan* apps for maximum cross-platform compatibility and portability, including on platforms, such as 
-*macOS*, *iOS*, and *tvOS*, where a native *Vulkan* driver is not available. 
+*macOS*, *iOS*, *tvOS*, and *visionOS*, where a native *Vulkan* driver is not available. 
 
 
 

fetchDependencies

@@ -4,7 +4,8 @@
 #
 # fetchDependencies - Retrieves the correct versions of all dependencies
 #
-# macOS usage: ./fetchDependencies [--macos] [--ios] [--iossim] [--tvos] [--tvossim] [--all] [--none]
+# macOS usage: ./fetchDependencies [--macos] [--ios] [--iossim] [--tvos] [--tvossim]
+#                                  [--visionos] [--visionossim] [--all] [--none]
 #                                  [-v] [--debug] [--build-spirv-tools]
 #                                  [--v-headers-root path] [--spirv-cross-root path] [--glslang-root path]
 #
@@ -33,9 +34,11 @@
 #              Build the external libraries for the visionOS Simulator platform.
 #
 #      --all
-#              Equivalent to specifying [--macos --ios --iossim --maccat --tvos --tvossim --visionos --visionossim].
+#              Equivalent to specifying [--macos --ios --iossim --maccat --tvos --tvossim].
 #              Results in one XCFramework for each external library, each containing
 #              binaries for all supported platforms.
+#              Currently excludes --visionos and --visionossim targets because those
+#              require Xcode 15+ and will abort a multi-platform build.
 #
 #      --none
 #              Don't build the external libraries for any platform (this is the default).
@@ -150,14 +153,14 @@ while (( "$#" )); do
          shift 1
          ;;
        --all)
+         BLD_MACOS="Y"
          BLD_IOS="Y"
          BLD_IOS_SIM="Y"
          BLD_MAC_CAT="Y"
          BLD_TVOS="Y"
          BLD_TVOS_SIM="Y"
-         BLD_VISIONOS="Y"
-         BLD_VISIONOS_SIM="Y"
-         BLD_MACOS="Y"
+#         BLD_VISIONOS="Y"              # Requires Xcode 15+
+#         BLD_VISIONOS_SIM="Y"          # Requires Xcode 15+
          shift 1
          ;;
        --none)