Add tests for multi-dim arrays and unbounded arrays (microsoft#5532)

I added at test for unbounded arrays. This case works, so no code
changes were required.

I also added a test for multi-dimensional arrays. This case is not
handled allowed in Vulkan, so I chose to issue an error. If we need to
support it, we could try improve it later by transforming the array into
a single dimensional array.

See https://gitlab.khronos.org/spirv/SPIR-V/-/issues/743 and
https://registry.khronos.org/vulkan/specs/1.3-extensions/html/vkspec.html#interfaces-resources-setandbinding.

tools/clang/lib/SPIRV/DeclResultIdMapper.cpp

@@ -1589,8 +1589,9 @@ void DeclResultIdMapper::createCounterVar(
   const SpirvType *counterType = spvContext.getACSBufferCounterType();
   QualType declType = decl->getType();
   if (declType->isArrayType()) {
-    // TODO(5440): This codes does not handle multi-dimensional arrays. We need
-    // to look at specific example to determine the best way to do it.
+    // Vulkan does not support multi-dimentional arrays of resource, so we
+    // assume the array is a single dimensional array.
+    assert(!declType->getArrayElementTypeNoTypeQual()->isArrayType());
     uint32_t arrayStride = 4;
     if (const auto *constArrayType =
             astContext.getAsConstantArrayType(declType)) {

tools/clang/lib/SPIRV/SpirvEmitter.cpp

@@ -1720,17 +1720,22 @@ void SpirvEmitter::doVarDecl(const VarDecl *decl) {
 
   // Reject arrays of RW/append/consume structured buffers. They have assoicated
   // counters, which are quite nasty to handle.
-  if (!spirvOptions.allowRWStructuredBufferArrays &&
-      decl->getType()->isArrayType()) {
-    auto type = decl->getType();
-    do {
-      type = type->getAsArrayTypeUnsafe()->getElementType();
-    } while (type->isArrayType());
-
-    if (isRWAppendConsumeSBuffer(type)) {
+  if (decl->getType()->isArrayType() &&
+      isRWAppendConsumeSBuffer(decl->getType())) {
+    if (!spirvOptions.allowRWStructuredBufferArrays) {
       emitError("arrays of RW/append/consume structured buffers unsupported",
                 loc);
       return;
+    } else if (decl->getType()
+                   ->getAsArrayTypeUnsafe()
+                   ->getElementType()
+                   ->isArrayType()) {
+      // See
+      // https://registry.khronos.org/vulkan/specs/1.3-extensions/html/vkspec.html#interfaces-resources-setandbinding
+      emitError("Multi-dimensional arrays of RW/append/consume structured "
+                "buffers are unsupported in Vulkan",
+                loc);
+      return;
     }
   }
 

tools/clang/test/CodeGenSPIRV/type.rwstructured-buffer.array.multidim.counter.error.hlsl

@@ -0,0 +1,17 @@
+// RUN: %dxc -T ps_6_6 -E main -fvk-allow-rwstructuredbuffer-arrays
+
+struct PSInput
+{
+	uint idx : COLOR;
+};
+
+RWStructuredBuffer<uint> g_rwbuffer[2][3] : register(u0, space2);
+
+float4 main(PSInput input) : SV_TARGET
+{
+    g_rwbuffer[1][input.idx].IncrementCounter();
+    return g_rwbuffer[input.idx][input.idx][0];
+}
+
+// CHECK: :8:26: error: Multi-dimensional arrays of RW/append/consume structured buffers are unsupported in Vulkan
+// CHECK: RWStructuredBuffer<uint> g_rwbuffer[2][3] : register(u0, space2);

tools/clang/test/CodeGenSPIRV/type.rwstructured-buffer.array.unbounded.counter.hlsl

@@ -0,0 +1,30 @@
+// RUN: %dxc -T ps_6_6 -E main -fvk-allow-rwstructuredbuffer-arrays
+
+struct PSInput
+{
+	uint idx : COLOR;
+};
+
+// CHECK: OpDecorate %g_rwbuffer DescriptorSet 2
+// CHECK: OpDecorate %g_rwbuffer Binding 0
+// CHECK: OpDecorate %counter_var_g_rwbuffer DescriptorSet 2
+// CHECK: OpDecorate %counter_var_g_rwbuffer Binding 1
+
+// CHECK: %g_rwbuffer = OpVariable %_ptr_Uniform__runtimearr_type_RWStructuredBuffer_uint Uniform
+// CHECK: %counter_var_g_rwbuffer = OpVariable %_ptr_Uniform__runtimearr_type_ACSBuffer_counter Uniform
+RWStructuredBuffer<uint> g_rwbuffer[] : register(u0, space2);
+
+float4 main(PSInput input) : SV_TARGET
+{
+// Correctly increment the counter.
+// CHECK: [[ac1:%\w+]] = OpAccessChain %_ptr_Uniform_type_ACSBuffer_counter %counter_var_g_rwbuffer {{%\d+}}
+// CHECK: [[ac2:%\w+]] = OpAccessChain %_ptr_Uniform_int [[ac1]] %uint_0
+// CHECK: OpAtomicIAdd %int [[ac2]] %uint_1 %uint_0 %int_1
+    g_rwbuffer[input.idx].IncrementCounter();
+
+// Correctly access the buffer.
+// CHECK: [[ac1:%\w+]] = OpAccessChain %_ptr_Uniform_type_RWStructuredBuffer_uint %g_rwbuffer {{%\d+}}
+// CHECK: [[ac2:%\w+]] = OpAccessChain %_ptr_Uniform_uint [[ac1]] %int_0 %uint_0
+// CHECK: OpLoad %uint [[ac2]]
+    return g_rwbuffer[input.idx][0];
+}

tools/clang/unittests/SPIRV/CodeGenSpirvTest.cpp

@@ -168,6 +168,13 @@ TEST_F(FileTest, RWStructuredBufferArrayCounterIndirect2) {
 TEST_F(FileTest, RWStructuredBufferArrayBindAttributes) {
   runFileTest("type.rwstructured-buffer.array.binding.attributes.hlsl");
 }
+TEST_F(FileTest, RWStructuredBufferUnboundedArray) {
+  runFileTest("type.rwstructured-buffer.array.unbounded.counter.hlsl");
+}
+TEST_F(FileTest, RWStructuredBufferMultiDimentionalArray) {
+  runFileTest("type.rwstructured-buffer.array.multidim.counter.error.hlsl",
+              Expect::Failure);
+}
 TEST_F(FileTest, AppendStructuredBufferArrayError) {
   runFileTest("type.append-structured-buffer.array.hlsl");
 }