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, 8 insertions, 0 deletions

diff --git a/source/slang/slang-type-layout.cpp b/source/slang/slang-type-layout.cpp
index 3f49d62d2..f7efd4ee4 100644
--- a/source/slang/slang-type-layout.cpp
+++ b/source/slang/slang-type-layout.cpp
@@ -3858,6 +3858,14 @@ static TypeLayoutResult _createTypeLayout(
             type,
             rules);
     }
+    else if (auto atomicType = as<GLSLAtomicUintType>(type))
+    {
+        ShaderParameterKind kind = ShaderParameterKind::AtomicUint;
+        return createSimpleTypeLayout(
+            rules->GetObjectLayout(kind, context.objectLayoutOptions),
+            type,
+            rules);
+    }
 
     // TODO: need a better way to handle this stuff...
 #define CASE(TYPE, KIND)                                                \