Fix atomic operations on RWBuffer (#593)

* Fix atomic operations on RWBuffer

An earlier change added support for passing true pointers to `__ref` parameters to fix the global `Interlocked*()` functions when applied to `groupshared` variables or `RWStructureBuffer<T>` elements.
That change didn't apply to `RWBuffer<T>` or `RWTexture2D<T>`, etc. because those types had so far only declared `get` and `set` accessors, but not any `ref` accessors (which return a pointer).

The main fixes here are:

* Add `ref` accessors to the subscript oeprations on the `RW*` resource types

* Adjust the logic for emitting calls to subscript accessors so that we don't get quite as eager about invoking a `ref` accessor, and instead try to invoke just a `get` or `set` accessor when these will suffice. This is important for Vulkan cross-compilation, where we don't yet support the semantics of our `ref` accessors.

* Add a test case for atomics on a `RWBuffer`

* Fix up `render-test` so that we can specify a format for a buffer resource, which allows us to use things other than `*StructuredBuffer` and `*ByteAddressBuffer`. The work there is probably not complete; I just did what I could to get the test working.

* A bunch of files got whitespace edits thanks to the fact that I'm using editorconfig and others on the project seemingly arent...

* fixup: remove ifdefed-out code

1 files changed, 9 insertions, 6 deletions

diff --git a/source/slang/emit.cpp b/source/slang/emit.cpp
index e0f71aafe..3f88ab82d 100644
--- a/source/slang/emit.cpp
+++ b/source/slang/emit.cpp
@@ -2363,15 +2363,18 @@ struct EmitVisitor
         // for temporary variables.
         auto type = inst->getDataType();
 
-        // First we unwrap any layers of pointer-ness and array-ness
-        // from the types to get at the underlying data type.
-        while (auto ptrType = as<IRPtrTypeBase>(type))
+        // Unwrap any layers of array-ness from the type, so that
+        // we can look at the underlying data type, in case we
+        // should *never* expose a value of that type
+        while (auto arrayType = as<IRArrayTypeBase>(type))
         {
-            type = ptrType->getValueType();
+            type = arrayType->getElementType();
         }
-        while (auto ptrType = as<IRArrayTypeBase>(type))
+
+        // Don't allow temporaries of pointer types to be created.
+        if(as<IRPtrTypeBase>(type))
         {
-            type = ptrType->getElementType();
+            return true;
         }
 
         // First we check for uniform parameter groups,