Add datalayout for constant buffers. (#5608)

* Add datalayout for constant buffers.

* Fixes.

* Fix test.

* Fix glsl codegen.

* Update spirv-specific doc.

* Fix test.

* Fix binding in the presense of specialization constants.

* address comments.

* Add a test for constant buffer layout.

3 files changed, 88 insertions, 0 deletions

diff --git a/tests/spirv/constant-buffer-layout.slang b/tests/spirv/constant-buffer-layout.slang
new file mode 100644
index 000000000..90aa1eef8
--- /dev/null
+++ b/tests/spirv/constant-buffer-layout.slang
@@ -0,0 +1,45 @@
+//TEST:SIMPLE(filecheck=SPIRV): -target spirv -emit-spirv-directly
+
+//SPIRV: ArrayStride 12
+
+struct Test
+{
+//SPIRV: Offset 0
+    uint v0;
+
+//SPIRV: Offset 4
+// matrix always start on a new register
+    float3x3 v1;
+//SPIRV: Offset 40
+// Non-matrix can pack with a partially filled register
+    uint v2;
+};
+
+ConstantBuffer<Test, ScalarDataLayout> buffer;
+
+//TEST_INPUT:ubuffer(data=[0], stride=4):out,name outputBuffer
+RWStructuredBuffer<int> outputBuffer;
+
+__generic<T : IArithmetic, let N : int>
+bool comp(vector<T,N> v1, vector<T,N> v2)
+{
+    for (uint i = 0; i < N; i++)
+        if (v1[i] != v2[i])
+            return false;
+
+    return true;
+}
+
+[shader("compute")]
+[numthreads(2, 2, 1)]
+void computeMain()
+{
+    // CHECK: 64
+    outputBuffer[0] = (true
+            && buffer.v0 == 1
+            && comp(buffer.v1[0], float3(2, 3, 4))
+            && comp(buffer.v1[1], float3(5, 6, 7))
+            && comp(buffer.v1[2], float3(8, 9, 10))
+            && buffer.v2 == 11
+        ) ? 100 : 0;
+}
\ No newline at end of file
diff --git a/tests/spirv/push-constant-layout.slang b/tests/spirv/push-constant-layout.slang
new file mode 100644
index 000000000..eb7d80f75
--- /dev/null
+++ b/tests/spirv/push-constant-layout.slang
@@ -0,0 +1,26 @@
+//TEST:SIMPLE(filecheck=CHECK): -target spirv -fvk-use-entrypoint-name
+// CHECK-NOT: std140
+struct Transform
+{
+    float4 Tint;
+    float2x2 ScaleRot;
+    float2 Translation;
+};
+
+[[vk::push_constant]]
+ConstantBuffer<Transform> transform1;
+
+RWStructuredBuffer<float> outputBuffer;
+
+[numthreads(1,1,1)]
+void computeMain1()
+{
+    outputBuffer[0] = transform1.Translation.x;
+}
+
+[numthreads(1,1,1)]
+void computeMain2(
+    [vk::push_constant] ConstantBuffer<Transform> transform2)
+{
+    outputBuffer[0] = transform2.Translation.x;
+}
\ No newline at end of file
diff --git a/tests/spirv/spec-constant-space.slang b/tests/spirv/spec-constant-space.slang
new file mode 100644
index 000000000..b4dd865c7
--- /dev/null
+++ b/tests/spirv/spec-constant-space.slang
@@ -0,0 +1,17 @@
+// Test that use of specialization constants does not cause space 0 to be reserved.
+
+//TEST:SIMPLE(filecheck=CHECK): -target spirv
+
+// CHECK-NOT: DescriptorSet 1
+
+struct MyData { float4 val; RWStructuredBuffer<float> outputBuffer; }
+
+
+[vk::specialization_constant]
+const int kSpecializationConstant = 0;
+
+[NumThreads(1,1,1)]
+void main(ParameterBlock<MyData> g_data)
+{
+    g_data.outputBuffer[0] = g_data.val.x;
+}
\ No newline at end of file