Remove use of @available() directive as it can cause issues in some build environments.

Generally replace use of @available() with respondsToSelector:.
Add mvkMakeOSVersion() and mvkOSVersionIsAtLeast(macos,ios) to help testing OS versions.
Set maxDrawIndexedIndexValue to kMVKUndefinedLargeUInt32 instead of uint32_t max.

Common/MVKOSExtensions.h

@@ -18,12 +18,17 @@
 
 #pragma once
 
+#include "MVKCommonEnvironment.h"
 #include <dispatch/dispatch.h>
 #include <string>
+#include <limits>
 
 
 typedef float MVKOSVersion;
 
+/*** Constant indicating unsupported functionality in an OS. */
+static const MVKOSVersion kMVKOSVersionUnsupported = std::numeric_limits<MVKOSVersion>::max();
+
 /**
  * Returns the operating system version as an MVKOSVersion, which is a float in which the
  * whole number portion indicates the major version, and the fractional portion indicates 
@@ -33,9 +38,29 @@ typedef float MVKOSVersion;
  */
 MVKOSVersion mvkOSVersion();
 
+/** Returns a MVKOSVersion built from the version components. */
+inline MVKOSVersion mvkMakeOSVersion(uint32_t major, uint32_t minor, uint32_t patch) {
+	return (float)major + ((float)minor / 100.0f) + ((float)patch / 10000.0f);
+}
+
 /** Returns whether the operating system version is at least minVer. */
 inline bool mvkOSVersionIsAtLeast(MVKOSVersion minVer) { return mvkOSVersion() >= minVer; }
 
+/**
+ * Returns whether the operating system version is at least the appropriate min version.
+ * The constant kMVKOSVersionUnsupported can be used for either value to cause the test
+ * to always fail on that OS, which is useful for indidicating functionalty guarded by
+ * this test is not supported on that OS.
+ */
+inline bool mvkOSVersionIsAtLeast(MVKOSVersion macOSMinVer, MVKOSVersion iOSMinVer) {
+#if MVK_MACOS
+	return mvkOSVersionIsAtLeast(macOSMinVer);
+#endif
+#if MVK_IOS
+	return mvkOSVersionIsAtLeast(iOSMinVer);
+#endif
+}
+
 /**
  * Returns a monotonic timestamp value for use in Vulkan and performance timestamping.
  *

Common/MVKOSExtensions.mm

@@ -29,17 +29,13 @@
 
 using namespace std;
 
-static const MVKOSVersion kMVKOSVersionUnknown = 0.0f;
-static MVKOSVersion _mvkOSVersion = kMVKOSVersionUnknown;
 MVKOSVersion mvkOSVersion() {
-    if (_mvkOSVersion == kMVKOSVersionUnknown) {
+	static MVKOSVersion _mvkOSVersion = 0;
-        NSOperatingSystemVersion osVer = [[NSProcessInfo processInfo] operatingSystemVersion];
+	if ( !_mvkOSVersion ) {
-        float maj = osVer.majorVersion;
+		NSOperatingSystemVersion osVer = [[NSProcessInfo processInfo] operatingSystemVersion];
-        float min = osVer.minorVersion;
+		_mvkOSVersion = mvkMakeOSVersion((uint32_t)osVer.majorVersion, (uint32_t)osVer.minorVersion, (uint32_t)osVer.patchVersion);
-        float pat = osVer.patchVersion;
+	}
-        _mvkOSVersion = maj + (min / 100.0f) +  + (pat / 10000.0f);
+	return _mvkOSVersion;
-    }
-    return _mvkOSVersion;
 }
 
 static uint64_t _mvkTimestampBase;

MoltenVK/MoltenVK/GPUObjects/MVKDevice.mm

@@ -1476,7 +1476,7 @@ void MVKPhysicalDevice::initProperties() {
     _properties.limits.maxComputeWorkGroupCount[1] = kMVKUndefinedLargeUInt32;
     _properties.limits.maxComputeWorkGroupCount[2] = kMVKUndefinedLargeUInt32;
 
-    _properties.limits.maxDrawIndexedIndexValue = numeric_limits<uint32_t>::max();
+    _properties.limits.maxDrawIndexedIndexValue = kMVKUndefinedLargeUInt32;
     _properties.limits.maxDrawIndirectCount = kMVKUndefinedLargeUInt32;
 
     _properties.limits.maxClipDistances = kMVKUndefinedLargeUInt32;

MoltenVK/MoltenVK/GPUObjects/MVKImage.mm

@@ -991,7 +991,7 @@ void MVKPresentableSwapchainImage::presentCAMetalDrawable(id<MTLCommandBuffer> m
 	}];
 	
 	if (hasPresentTime) {
-		if (@available(iOS 10.3, macOS 10.15.4, *)) {
+		if ([_mtlDrawable respondsToSelector: @selector(addPresentedHandler:)]) {
 			[_mtlDrawable addPresentedHandler: ^(id<MTLDrawable> drawable) {
 				// Record the presentation time
 				CFTimeInterval presentedTimeSeconds = drawable.presentedTime;

MoltenVK/MoltenVK/GPUObjects/MVKSwapchain.mm

@@ -383,19 +383,19 @@ void MVKSwapchain::initSurfaceImages(const VkSwapchainCreateInfoKHR* pCreateInfo
 }
 
 VkResult MVKSwapchain::getRefreshCycleDuration(VkRefreshCycleDurationGOOGLE *pRefreshCycleDuration) {
-#if MVK_IOS
 	NSInteger framesPerSecond = 60;
-	if (@available(iOS 10.3, *)) {
+
-		framesPerSecond = [UIScreen mainScreen].maximumFramesPerSecond;
+#if MVK_IOS
-	} else {
+	UIScreen* screen = [UIScreen mainScreen];
-		// TODO: fallback
+	if ([screen respondsToSelector: @selector(maximumFramesPerSecond)]) {
+		framesPerSecond = screen.maximumFramesPerSecond;
 	}
 #endif
 #if MVK_MACOS
 	// TODO: hook this up for macOS, probably need to use CGDisplayModeGetRefeshRate
-	NSInteger framesPerSecond = 60;
 #endif
-	pRefreshCycleDuration->refreshDuration = 1e9 / ( uint64_t ) framesPerSecond;
+
+	pRefreshCycleDuration->refreshDuration = (uint64_t)1e9 / framesPerSecond;
 	return VK_SUCCESS;
 }
 

MoltenVKShaderConverter/MoltenVKShaderConverter.xcodeproj/project.pbxproj

@@ -836,9 +836,10 @@
 				CLANG_WARN_INT_CONVERSION = YES;
 				CLANG_WARN_OBJC_IMPLICIT_RETAIN_SELF = YES;
 				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
-				CLANG_WARN_SUSPICIOUS_IMPLICIT_CONVERSION = YES;
+				CLANG_WARN_SUSPICIOUS_IMPLICIT_CONVERSION = NO;
 				CLANG_WARN_SUSPICIOUS_MOVE = YES;
-				CLANG_WARN_UNREACHABLE_CODE = NO;
+				CLANG_WARN_UNGUARDED_AVAILABILITY = NO;
+				CLANG_WARN_UNREACHABLE_CODE = YES;
 				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
 				COPY_PHASE_STRIP = NO;
 				ENABLE_STRICT_OBJC_MSGSEND = YES;
@@ -855,8 +856,8 @@
 				GCC_WARN_HIDDEN_VIRTUAL_FUNCTIONS = YES;
 				GCC_WARN_NON_VIRTUAL_DESTRUCTOR = YES;
 				GCC_WARN_UNDECLARED_SELECTOR = YES;
+				GCC_WARN_UNINITIALIZED_AUTOS = YES_AGGRESSIVE;
 				GCC_WARN_UNUSED_FUNCTION = YES;
-				GCC_WARN_UNUSED_PARAMETER = YES;
 				GCC_WARN_UNUSED_VARIABLE = NO;
 				HEADER_SEARCH_PATHS = (
 					"$(inherited)",
@@ -890,9 +891,10 @@
 				CLANG_WARN_INT_CONVERSION = YES;
 				CLANG_WARN_OBJC_IMPLICIT_RETAIN_SELF = YES;
 				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
-				CLANG_WARN_SUSPICIOUS_IMPLICIT_CONVERSION = YES;
+				CLANG_WARN_SUSPICIOUS_IMPLICIT_CONVERSION = NO;
 				CLANG_WARN_SUSPICIOUS_MOVE = YES;
-				CLANG_WARN_UNREACHABLE_CODE = NO;
+				CLANG_WARN_UNGUARDED_AVAILABILITY = NO;
+				CLANG_WARN_UNREACHABLE_CODE = YES;
 				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
 				COPY_PHASE_STRIP = YES;
 				ENABLE_NS_ASSERTIONS = NO;
@@ -909,8 +911,8 @@
 				GCC_WARN_HIDDEN_VIRTUAL_FUNCTIONS = YES;
 				GCC_WARN_NON_VIRTUAL_DESTRUCTOR = YES;
 				GCC_WARN_UNDECLARED_SELECTOR = YES;
+				GCC_WARN_UNINITIALIZED_AUTOS = YES_AGGRESSIVE;
 				GCC_WARN_UNUSED_FUNCTION = YES;
-				GCC_WARN_UNUSED_PARAMETER = YES;
 				GCC_WARN_UNUSED_VARIABLE = NO;
 				HEADER_SEARCH_PATHS = (
 					"$(inherited)",

MoltenVKShaderConverter/MoltenVKShaderConverterTool/OSSupport.mm

@@ -19,6 +19,7 @@
 #include "OSSupport.h"
 #include "FileSupport.h"
 #include "MoltenVKShaderConverterTool.h"
+#include "MVKOSExtensions.h"
 
 #import <Foundation/Foundation.h>
 #import <Metal/Metal.h>
@@ -71,13 +72,9 @@ bool mvk::compile(const string& mslSourceCode,
 
 	MTLLanguageVersion mslVerEnum = (MTLLanguageVersion)0;
 	if (mslVer(2, 1, 0)) {
-		if (@available(macOS 10.14, *)) {
+		mslVerEnum = MTLLanguageVersion2_1;
-			mslVerEnum = MTLLanguageVersion2_1;
-		}
 	} else if (mslVer(2, 0, 0)) {
-		if (@available(macOS 10.13, *)) {
+		mslVerEnum = MTLLanguageVersion2_0;
-			mslVerEnum = MTLLanguageVersion2_0;
-		}
 	} else if (mslVer(1, 2, 0)) {
 		mslVerEnum = MTLLanguageVersion1_2;
 	} else if (mslVer(1, 1, 0)) {