Make -fvk-u-shift work on AppendStructuredBuffer. (shader-slang#3144)

Co-authored-by: Yong He <yhe@nvidia.com>

Author: csyonghe

source/slang/slang-ir-lower-append-consume-structured-buffer.cpp

@@ -177,13 +177,29 @@ namespace Slang
                         IRBuilder subBuilder(typeUser);
                         IRVarLayout::Builder newVarLayoutBuilder(&subBuilder, typeLayout);
                         newVarLayoutBuilder.cloneEverythingButOffsetsFrom(varLayout);
+                        IRVarOffsetAttr* uavOffsetAttr = nullptr;
+                        IRVarOffsetAttr* descriptorTableSlotOffsetAttr = nullptr;
+
                         for (auto offsetAttr : varLayout->getOffsetAttrs())
                         {
+                            if (offsetAttr->getResourceKind() == LayoutResourceKind::UnorderedAccess)
+                                uavOffsetAttr = offsetAttr;
+                            else if (offsetAttr->getResourceKind() == LayoutResourceKind::DescriptorTableSlot)
+                                descriptorTableSlotOffsetAttr = offsetAttr;
                             auto info = newVarLayoutBuilder.findOrAddResourceInfo(offsetAttr->getResourceKind());
                             info->offset = offsetAttr->getOffset();
                             info->space = offsetAttr->getSpace();
                             info->kind = offsetAttr->getResourceKind();
                         }
+                        // If the user provided an layout offset for UAV but not for descriptor table slot, then
+                        // we use the UAV offset for the descriptor table slot offset.
+                        if (uavOffsetAttr && !descriptorTableSlotOffsetAttr)
+                        {
+                            auto info = newVarLayoutBuilder.findOrAddResourceInfo(LayoutResourceKind::DescriptorTableSlot);
+                            info->offset = uavOffsetAttr->getOffset();
+                            info->space = uavOffsetAttr->getSpace();
+                            info->kind = LayoutResourceKind::DescriptorTableSlot;
+                        }
                         auto newVarLayout = newVarLayoutBuilder.build();
                         subBuilder.addLayoutDecoration(typeUser, newVarLayout);
                         varLayout->removeAndDeallocate();

tests/hlsl/append-structured-buffer.slang

@@ -1,5 +1,5 @@
 
-//TEST:SIMPLE(filecheck=GLSL):-target glsl -profile glsl_450 -stage compute -entry computeMain
+//TEST:SIMPLE(filecheck=GLSL):-target glsl -profile glsl_450 -stage compute -entry computeMain -fvk-u-shift 10 0
 //TEST:SIMPLE(filecheck=SPIRV):-target spirv -profile glsl_450 -stage compute -entry computeMain
 
 //DISABLED_TEST(compute, vulkan):COMPARE_COMPUTE_EX:-vk -compute -shaderobj -output-using-type -xslang -fvk-use-gl-layout
@@ -9,11 +9,11 @@ RWStructuredBuffer<float> outputBuffer;
 
 AppendStructuredBuffer<float2> appendBuffer;
 
-// GLSL: layout(std430, binding = 1) buffer StructuredBuffer_float2_t
+// GLSL: layout(std430, binding = 11) buffer StructuredBuffer_float2_t
 // GLSL: vec2 _data[];
 // GLSL: } appendBuffer_elements_0
 
-// GLSL: layout(std430, binding = 2) buffer StructuredBuffer_int_t
+// GLSL: layout(std430, binding = 12) buffer StructuredBuffer_int_t
 // GLSL: int _data[];
 // GLSL: } appendBuffer_counter