More fixups for parameter block binding generation (#311)

* More fixups for parameter block binding generation

The bug in this case arises when there is both a parameter block and global-scope resources, all of which are relying on automatic binding assignment. If the parameter block is the first global-scope parameter that gets encountered, then it is possible for it to allocate regsiter space/set zero for itself, which confuses the logic for handling other global-scope parameters (which assumes that *they* get space/set zero).

I've also made some fixup to the reflection test harness and reflection API code:

- Have the hardness handle register-space allocations when printing, and be sure to only show their `index` and not their `space` (since that would be redundant)

- Have the reflection API only auto-redirect queries on a parameter group type layout to its container type layout *if* the container type layout has a non-zero number of resource allocations. The problem that arises here is a `ParameterBlock<X>` where `X` doesn't contain any uniforms, so that no container is needed. In that case the container ends up with no resource allocation(s).

* Fixups for test failures.

- The thread-group size tests failed because they had shader parameters with no resources to back them (built-in `SV_` inputs), and the printing of those changed. I fixed up the baseline, but also had to fix a few bugs in the reflection test fixture's printing logic.

- The GLSL parameter block test revealed a corner case of the existing logic: because we always need to generate a binding for the "hack" sampler (even if code doesn't end up needing it), and that sampler should always go in the "default" set (should be set zero), the user's `ParameterBlock` will always end up as `set=1` or later, even if there are no other global-scope parameters.

  - This will be fixed once we don't have to rely on glslang's annoying behavior in this one case, either because glslang gets fixed, or because we implement our own SPIR-V codegen.

4 files changed, 72 insertions, 7 deletions

diff --git a/tests/reflection/parameter-block.slang b/tests/reflection/parameter-block.slang
new file mode 100644
index 000000000..c20337480
--- /dev/null
+++ b/tests/reflection/parameter-block.slang
@@ -0,0 +1,19 @@
+//TEST:REFLECTION:-profile glsl_fragment -target glsl
+
+// Confirm that we do parameter binding correctly
+// when we have both a parameter block *and* user-defined
+// resource parameters that both need automatic
+// binding allocation.
+
+struct Helper
+{
+	Texture2D t;
+	SamplerState s;	
+};
+
+ParameterBlock<Helper> a;
+
+Texture2D b;
+
+float4 main() : SV_target
+{ return 0.0; }
diff --git a/tests/reflection/parameter-block.slang.expected b/tests/reflection/parameter-block.slang.expected
new file mode 100644
index 000000000..bc04d79ed
--- /dev/null
+++ b/tests/reflection/parameter-block.slang.expected
@@ -0,0 +1,52 @@
+result code = 0
+standard error = {
+}
+standard output = {
+{
+    "parameters": [
+        {
+            "name": "a",
+            "binding": {"kind": "registerSpace", "index": 1},
+            "type": {
+                "kind": "parameterBlock",
+                "elementType": {
+                    "kind": "struct",
+                    "name": "Helper",
+                    "fields": [
+                        {
+                            "name": "t",
+                            "type": {
+                                "kind": "resource",
+                                "baseShape": "texture2D"
+                            },
+                            "binding": {"kind": "descriptorTableSlot", "index": 0}
+                        },
+                        {
+                            "name": "s",
+                            "type": {
+                                "kind": "samplerState"
+                            },
+                            "binding": {"kind": "descriptorTableSlot", "index": 1}
+                        }
+                    ]
+                }
+            }
+        },
+        {
+            "name": "b",
+            "binding": {"kind": "descriptorTableSlot", "index": 0},
+            "type": {
+                "kind": "resource",
+                "baseShape": "texture2D"
+            }
+        },
+        {
+            "name": "SLANG_hack_samplerForTexelFetch",
+            "binding": {"kind": "descriptorTableSlot", "index": 1},
+            "type": {
+                "kind": "samplerState"
+            }
+        }
+    ]
+}
+}
diff --git a/tests/reflection/thread-group-size.comp.expected b/tests/reflection/thread-group-size.comp.expected
index ea7e97851..facd52cc0 100644
--- a/tests/reflection/thread-group-size.comp.expected
+++ b/tests/reflection/thread-group-size.comp.expected
@@ -21,10 +21,7 @@ standard output = {
                                     "kind": "scalar",
                                     "scalarType": "float32"
                                 }
-                            },
-                            "bindings": [
-
-                            ]
+                            }
                         }
                     ]
                 }
diff --git a/tests/reflection/thread-group-size.hlsl.expected b/tests/reflection/thread-group-size.hlsl.expected
index a41c66248..cd5d09e35 100644
--- a/tests/reflection/thread-group-size.hlsl.expected
+++ b/tests/reflection/thread-group-size.hlsl.expected
@@ -21,9 +21,6 @@ standard output = {
             "parameters": [
                 {
                     "name": "tid",
-                    "bindings": [
-
-                    ],
                     "semanticName": "SV_DISPATCHTHREADID",
                     "type": {
                         "kind": "vector",