Implement glsl atomic's [non image or memory scope] with optional extension(s); resolves #3587 for GLSL & SPIR-V targets (#3755)

The following commit implements atomic operations & types associated with OpenGL 4.6, GL_EXT_vulkan_glsl_relaxed, GLSL_EXT_shader_atomic_float, GLSL_EXT_shader_atomic_float2, for GLSL & SPIR-V targets.

Fully implements all functions, and built-in type's, resolves https://github.com/shader-slang/slang/issues/3560 for GLSL & SPRI-V targets.

[Atomic extensions for GLSL can be found here](https://github.com/KhronosGroup/GLSL/tree/main)

Notes of worth:

* atomic_uint is well defined in GLSL->OpenGL, although was removed in GLSL->VK unless a compiler extension is supported (GL_EXT_vulkan_glsl_relaxed). This support entails transforming all atomic_uint operations and references into a storage buffer. SPIR-V has AtomicCounter+AtomicStorage (atomic_uint parallel) but does not implement these capabilities for SPIR-V->VK in any scenario. Due to the case we transform atomic_uint ourselves (GLSL_Syntax->Slang_IR) to accommodate transforming atomic_uint into valid syntax.
* GLSL_EXT_shader_atomic_float2 (all float16_t & some float/double operations) support is minimal and worth watching out for if enabling the tests. 

1 files changed, 14 insertions, 3 deletions

diff --git a/tools/gfx/vulkan/vk-device.cpp b/tools/gfx/vulkan/vk-device.cpp
index 2a914b86b..1b046d8f2 100644
--- a/tools/gfx/vulkan/vk-device.cpp
+++ b/tools/gfx/vulkan/vk-device.cpp
@@ -476,13 +476,17 @@ Result DeviceImpl::initVulkanInstanceAndDevice(
         extendedFeatures.clockFeatures.pNext = deviceFeatures2.pNext;
         deviceFeatures2.pNext = &extendedFeatures.clockFeatures;
 
-        // Atomic Float
+        // Atomic Float 
         // To detect atomic float we need
         // https://www.khronos.org/registry/vulkan/specs/1.2-extensions/man/html/VkPhysicalDeviceShaderAtomicFloatFeaturesEXT.html
 
         extendedFeatures.atomicFloatFeatures.pNext = deviceFeatures2.pNext;
         deviceFeatures2.pNext = &extendedFeatures.atomicFloatFeatures;
 
+        // https://registry.khronos.org/vulkan/specs/1.3-extensions/man/html/VkPhysicalDeviceShaderAtomicFloat2FeaturesEXT.html
+        extendedFeatures.atomicFloat2Features.pNext = deviceFeatures2.pNext;
+        deviceFeatures2.pNext = &extendedFeatures.atomicFloat2Features;
+
         // mesh shader features
         extendedFeatures.meshShaderFeatures.pNext = deviceFeatures2.pNext;
         deviceFeatures2.pNext = &extendedFeatures.meshShaderFeatures;
@@ -543,7 +547,7 @@ Result DeviceImpl::initVulkanInstanceAndDevice(
         // SIMPLE_EXTENSION_FEATURE(struct, feature member name, extension
         // name, features...) will check for the presence of the boolean
         // feature member in struct and the availability of the extensions. If
-        // they are both present then the extensions are addded, the struct
+        // they are both present then the extensions are added, the struct
         // linked into the deviceCreateInfo chain and the features added to the
         // supported features list.
 #define SIMPLE_EXTENSION_FEATURE(s, m, e, ...) \
@@ -563,12 +567,19 @@ Result DeviceImpl::initVulkanInstanceAndDevice(
 
         SIMPLE_EXTENSION_FEATURE(
             extendedFeatures.atomicFloatFeatures,
-            shaderBufferFloat32AtomicAdd,
+            shaderBufferFloat32Atomics,
             VK_EXT_SHADER_ATOMIC_FLOAT_EXTENSION_NAME,
             "atomic-float"
         );
 
         SIMPLE_EXTENSION_FEATURE(
+            extendedFeatures.atomicFloat2Features,
+            shaderBufferFloat16Atomics,
+            VK_EXT_SHADER_ATOMIC_FLOAT_2_EXTENSION_NAME,
+            "atomic-float-2"
+        );
+
+        SIMPLE_EXTENSION_FEATURE(
             extendedFeatures.extendedDynamicStateFeatures,
             extendedDynamicState,
             VK_EXT_EXTENDED_DYNAMIC_STATE_EXTENSION_NAME,