Implement 8.14-8.19 of OpenGL-GLSL specification

The following PR implements 8.14-8.19 of the [OpenGL-GLSL specification](https://registry.khronos.org/OpenGL/specs/gl/GLSLangSpec.4.60.pdf).

Fully implements all functions and built-in type's, resolves https://github.com/shader-slang/slang/issues/3692 for GLSL & SPRI-V targets.

_Notes:_
Testing Tools:
* Fragment shaders cannot test computational results. Only OpCodes are checked for proper emitting.

Implementation Notes:
* SubpassInput requires an unknown image format.
* SubpassInput is disjoint from TextureType: __SubpassImpl (.slang) & SubpassInputType (Compiler) to reduce code generation required.
* SubpassInput required an additional input layout modifier, input_attachment_index, this was added as a new parameter binding attribute. Since the following qualifiers can overlap with different resources (`layout(input_attachment_index = 0, binding = 0, set = 0)`) input_attachment_index is checked for overlapping resource bindings separately from other qualifiers with `LayoutResourceKind::InputAttachmentIndex`.
* `GLSLInputAttachmentIndexLayoutModifier` was added to enforce function parameters only accepting `in` decorated variables.
* `in` decorated variables needed to have emitting modified to allow directly emitting the variable into function calls if used as a parameter, normally Slang has a "global variable" shadow as a "global parameter" through a copy. This does not work and is solved using `GlobalVariableShadowingGlobalParameterDecoration` to build a relationship of "global variable" to "global parameter", we then resolve this relationship and replace "global variable" uses later in compile.
* `AtomicCounterMemory` memory-constraint requires `OpCapability AtomicStorage`, `AtomicStorage` is invalid for Vulkan targets. glslang outputs for `barrier`, `memoryBarrier`, and `groupMemoryBarrier` `AtomicCounterMemory` as a memory constraint. This compiles as valid SPIR-V for Vulkan since `OpCapability AtomicStorage` is not declared. This behavior of glslang is undefined as per [3.31.Capability of the SPIR-V specification](https://registry.khronos.org/SPIR-V/specs/unified1/SPIRV.html#_capability). We will omit `AtomicCounterMemory` from our barrier calls.

6 files changed, 197 insertions, 0 deletions

diff --git a/tests/glsl-intrinsic/subpass-input/input-attachment-index-overlapping-error1.slang b/tests/glsl-intrinsic/subpass-input/input-attachment-index-overlapping-error1.slang
new file mode 100644
index 000000000..82b56f872
--- /dev/null
+++ b/tests/glsl-intrinsic/subpass-input/input-attachment-index-overlapping-error1.slang
@@ -0,0 +1,23 @@
+//TEST:SIMPLE(filecheck=CHECK): -target glsl -stage fragment -entry main -allow-glsl
+//TEST:SIMPLE(filecheck=CHECK): -target spirv -emit-spirv-directly -stage fragment -entry main -allow-glsl
+#version 450
+// CHECK: warning 39001
+buffer MyBlockName
+{
+    uvec4 idata[2];
+} keepAliveBuffer;
+
+layout(location = 0) in highp vec4 a_position;
+layout(location = 0) in highp vec4 b_position;
+
+layout (input_attachment_index = 2, set = 0, binding = 0) uniform isubpassInput isubpass;
+layout (input_attachment_index = 2, set = 0, binding = 1) uniform isubpassInputMS isubpassMS;
+
+layout (location = 0) out vec4 outColor;
+
+void main() {
+    keepAliveBuffer.idata[0] = subpassLoad(isubpass);
+    keepAliveBuffer.idata[1] = subpassLoad(isubpassMS, 0);
+
+    outColor = vec4(0);
+}
\ No newline at end of file
diff --git a/tests/glsl-intrinsic/subpass-input/input-attachment-index-overlapping-error2.slang b/tests/glsl-intrinsic/subpass-input/input-attachment-index-overlapping-error2.slang
new file mode 100644
index 000000000..d70377660
--- /dev/null
+++ b/tests/glsl-intrinsic/subpass-input/input-attachment-index-overlapping-error2.slang
@@ -0,0 +1,20 @@
+//TEST:SIMPLE(filecheck=CHECK): -target glsl -stage fragment -entry main -allow-glsl
+//TEST:SIMPLE(filecheck=CHECK): -target spirv -emit-spirv-directly -stage fragment -entry main -allow-glsl
+#version 450
+// CHECK: warning 39001
+buffer MyBlockName
+{
+    uvec4 idata[2];
+} keepAliveBuffer;
+
+layout (input_attachment_index = 0, set = 0, binding = 1) uniform isubpassInput isubpass;
+layout (input_attachment_index = 1, set = 0, binding = 1) uniform isubpassInputMS isubpassMS;
+
+layout (location = 0) out vec4 outColor;
+
+void main() {
+    keepAliveBuffer.idata[0] = subpassLoad(isubpass);
+    keepAliveBuffer.idata[1] = subpassLoad(isubpassMS, 0);
+
+    outColor = vec4(0);
+}
\ No newline at end of file
diff --git a/tests/glsl-intrinsic/subpass-input/input-attachment-index-overlapping-error3.slang b/tests/glsl-intrinsic/subpass-input/input-attachment-index-overlapping-error3.slang
new file mode 100644
index 000000000..c2396dbfe
--- /dev/null
+++ b/tests/glsl-intrinsic/subpass-input/input-attachment-index-overlapping-error3.slang
@@ -0,0 +1,20 @@
+//TEST:SIMPLE(filecheck=CHECK): -target glsl -stage fragment -entry main -allow-glsl
+//TEST:SIMPLE(filecheck=CHECK): -target spirv -emit-spirv-directly -stage fragment -entry main -allow-glsl
+#version 450
+// CHECK: warning 39001
+buffer MyBlockName
+{
+    uvec4 idata[2];
+} keepAliveBuffer;
+
+layout (input_attachment_index = 0, binding = 1) uniform isubpassInput isubpass;
+layout (input_attachment_index = 1, binding = 1) uniform isubpassInputMS isubpassMS;
+
+layout (location = 0) out vec4 outColor;
+
+void main() {
+    keepAliveBuffer.idata[0] = subpassLoad(isubpass);
+    keepAliveBuffer.idata[1] = subpassLoad(isubpassMS, 0);
+
+    outColor = vec4(0);
+}
\ No newline at end of file
diff --git a/tests/glsl-intrinsic/subpass-input/input-attachment-index-use-error.slang b/tests/glsl-intrinsic/subpass-input/input-attachment-index-use-error.slang
new file mode 100644
index 000000000..889a4e205
--- /dev/null
+++ b/tests/glsl-intrinsic/subpass-input/input-attachment-index-use-error.slang
@@ -0,0 +1,11 @@
+//TEST:SIMPLE(filecheck=CHECK): -target glsl -stage fragment -entry main -allow-glsl
+#version 450
+
+// CHECK: error 31207
+layout (input_attachment_index = 1, set = 0, binding = 1) uniform vec3 image;
+
+layout (location = 0) out vec4 outColor;
+
+void main() {
+    outColor = vec4(0);
+}
\ No newline at end of file
diff --git a/tests/glsl-intrinsic/subpass-input/subpass-input-as-parameter.slang b/tests/glsl-intrinsic/subpass-input/subpass-input-as-parameter.slang
new file mode 100644
index 000000000..a415fcf81
--- /dev/null
+++ b/tests/glsl-intrinsic/subpass-input/subpass-input-as-parameter.slang
@@ -0,0 +1,35 @@
+//TEST:SIMPLE(filecheck=CHECK_GLSL): -target glsl -stage fragment -entry main -allow-glsl
+//TEST:SIMPLE(filecheck=CHECK_SPV): -target spirv -emit-spirv-directly -stage fragment -entry main -allow-glsl
+
+#version 450
+
+// CHECK_SPV-DAG: InputAttachmentIndex 0
+// CHECK_SPV-DAG: OpTypeImage %float SubpassData 2 0 0 2 Unknown
+// CHECK_GLSL: subpassInput
+
+layout (input_attachment_index = 0, set = 0, binding = 0) uniform subpassInput subpass;
+
+// CHECK_SPV-DAG: InputAttachmentIndex 1
+// CHECK_SPV-DAG: OpTypeImage %float SubpassData 2 0 1 2 Unknown
+// CHECK_GLSL: subpassInputMS
+layout (input_attachment_index = 1, set = 0, binding = 1) uniform subpassInputMS subpassMS;
+
+layout (location = 0) out vec4 outColor;
+
+void someSideEffect(subpassInput subpassTmp)
+{
+    outColor.xy = subpassLoad(subpassTmp).xy;
+}
+
+void someSideEffectMS(subpassInputMS subpassTmp)
+{
+    outColor.zw = subpassLoad(subpassTmp, 0).zw;
+}
+
+// CHECK_GLSL-DAG: void main(
+// CHECK_SPV-DAG: OpEntryPoint
+
+void main() {
+    someSideEffect(subpass);
+    someSideEffectMS(subpassMS);
+}
\ No newline at end of file
diff --git a/tests/glsl-intrinsic/subpass-input/subpass-input.slang b/tests/glsl-intrinsic/subpass-input/subpass-input.slang
new file mode 100644
index 000000000..0597cc06c
--- /dev/null
+++ b/tests/glsl-intrinsic/subpass-input/subpass-input.slang
@@ -0,0 +1,88 @@
+//TEST:SIMPLE(filecheck=CHECK_GLSL): -target glsl -stage fragment -entry main -allow-glsl
+//TEST:SIMPLE(filecheck=CHECK_SPV): -target spirv -emit-spirv-directly -stage fragment -entry main -allow-glsl
+//TEST:SIMPLE(filecheck=CHECK_HLSL): -target hlsl -stage fragment -entry main -allow-glsl
+
+#version 450
+// CHECK_SPV-DAG: OpEntryPoint
+
+// CHECK_SPV-DAG: InputAttachmentIndex 0
+// CHECK_SPV-DAG: InputAttachmentIndex 1
+// CHECK_SPV-DAG: InputAttachmentIndex 2
+// CHECK_SPV-DAG: InputAttachmentIndex 3
+// CHECK_SPV-DAG: InputAttachmentIndex 4
+// CHECK_SPV-DAG: InputAttachmentIndex 5
+
+// CHECK_SPV-DAG: OpTypeImage %float SubpassData 2 0 0 2 Unknown
+// CHECK_GLSL-DAG: input_attachment_index = 0
+// CHECK_GLSL-DAG: subpassInput
+// CHECK_HLSL-DAG: vk::input_attachment_index(0)
+// CHECK_HLSL-DAG: SubpassInput<float4>
+layout (input_attachment_index = 0, set = 0, binding = 0) uniform subpassInput subpass;
+
+// CHECK_SPV-DAG: OpTypeImage %float SubpassData 2 0 1 2 Unknown
+// CHECK_GLSL-DAG: input_attachment_index = 1
+// CHECK_GLSL-DAG: subpassInputMS
+// CHECK_HLSL-DAG: vk::input_attachment_index(1)
+// CHECK_HLSL-DAG: SubpassInputMS<float4>
+layout (input_attachment_index = 1, set = 0, binding = 1) uniform subpassInputMS subpassMS;
+
+// CHECK_SPV-DAG: OpTypeImage %uint SubpassData 2 0 0 2 Unknown
+// CHECK_GLSL-DAG: input_attachment_index = 2
+// CHECK_GLSL-DAG: usubpassInput
+// CHECK_HLSL-DAG: vk::input_attachment_index(2)
+// CHECK_HLSL-DAG: SubpassInput<uint4>
+layout (input_attachment_index = 2, set = 0, binding = 2) uniform usubpassInput usubpass;
+
+// CHECK_SPV-DAG: OpTypeImage %uint SubpassData 2 0 1 2 Unknown
+// CHECK_GLSL-DAG: input_attachment_index = 3
+// CHECK_GLSL-DAG: usubpassInputMS
+// CHECK_HLSL-DAG: vk::input_attachment_index(3)
+// CHECK_HLSL-DAG: SubpassInputMS<uint4>
+layout (input_attachment_index = 3, set = 0, binding = 3) uniform usubpassInputMS usubpassMS;
+
+// CHECK_SPV-DAG: OpTypeImage %int SubpassData 2 0 0 2 Unknown
+// CHECK_GLSL-DAG: input_attachment_index = 4
+// CHECK_GLSL-DAG: isubpassInput
+// CHECK_HLSL-DAG: vk::input_attachment_index(4)
+// CHECK_HLSL-DAG: SubpassInput<int4>
+layout (input_attachment_index = 4, set = 0, binding = 4) uniform isubpassInput isubpass;
+
+// CHECK_SPV-DAG: OpTypeImage %int SubpassData 2 0 1 2 Unknown
+// CHECK_GLSL-DAG: input_attachment_index = 5
+// CHECK_GLSL-DAG: isubpassInputMS
+// CHECK_HLSL-DAG: vk::input_attachment_index(5)
+// CHECK_HLSL-DAG: SubpassInputMS<int4>
+layout (input_attachment_index = 5, set = 0, binding = 5) uniform isubpassInputMS isubpassMS;
+
+layout (location = 0) out vec4 outColor;
+
+// CHECK_GLSL-DAG: void main()
+// CHECK_HLSL-DAG: main()
+void main() {
+// CHECK_SPV: OpImageRead
+// CHECK_GLSL: subpassLoad
+// CHECK_HLSL: SubpassLoad
+// CHECK_SPV: OpImageRead
+// CHECK_GLSL: subpassLoad
+// CHECK_HLSL: SubpassLoad
+// CHECK_SPV: OpImageRead
+// CHECK_GLSL: subpassLoad
+// CHECK_HLSL: SubpassLoad
+// CHECK_SPV: OpImageRead
+// CHECK_GLSL: subpassLoad
+// CHECK_HLSL: SubpassLoad
+// CHECK_SPV: OpImageRead
+// CHECK_GLSL: subpassLoad
+// CHECK_HLSL: SubpassLoad
+// CHECK_SPV: OpImageRead
+// CHECK_GLSL: subpassLoad
+// CHECK_HLSL: SubpassLoad
+    outColor = vec4(true
+        && subpassLoad(subpass) == vec4(1)
+        && subpassLoad(subpassMS, 0) == vec4(1)
+        && subpassLoad(isubpass) == ivec4(1)
+        && subpassLoad(isubpassMS, 0) == ivec4(1)
+        && subpassLoad(usubpass) == uvec4(1)
+        && subpassLoad(usubpassMS, 0) == uvec4(1)
+    );
+}
\ No newline at end of file