Fix -fvk-u-shift not applying to global constant buffer. (#3033)

* Fix -fvk-u-shift not applying to global constant buffer.

* Fix test.

* Fix.

* Fix.

---------

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

5 files changed, 61 insertions, 5 deletions

diff --git a/source/slang/slang-emit-glsl.cpp b/source/slang/slang-emit-glsl.cpp
index 37c38dd95..321f41d54 100644
--- a/source/slang/slang-emit-glsl.cpp
+++ b/source/slang/slang-emit-glsl.cpp
@@ -241,7 +241,10 @@ void GLSLSourceEmitter::_emitGLSLByteAddressBuffer(IRGlobalParam* varDecl, IRByt
     {
         // We can use ShaderResource/DescriptorSlot interchangably here. 
         // This is possible because vk-shift-*
-        const LayoutResourceKindFlags kinds = LayoutResourceKindFlag::ShaderResource | LayoutResourceKindFlag::DescriptorTableSlot;
+        bool isReadOnly = (as<IRHLSLByteAddressBufferType>(byteAddressBufferType) != nullptr);
+
+        const LayoutResourceKindFlags kinds = (isReadOnly ? LayoutResourceKindFlag::ShaderResource : LayoutResourceKindFlag::UnorderedAccess)
+            | LayoutResourceKindFlag::DescriptorTableSlot;
 
         EmitVarChain chain(layout);
 
diff --git a/source/slang/slang-parameter-binding.cpp b/source/slang/slang-parameter-binding.cpp
index 51279b605..47f370854 100644
--- a/source/slang/slang-parameter-binding.cpp
+++ b/source/slang/slang-parameter-binding.cpp
@@ -3634,7 +3634,8 @@ static void _appendRange(Index start, LayoutSize size, StringBuilder& ioBuf)
 }
 
 static void _maybeApplyHLSLToVulkanShifts(
-    ParameterBindingContext* paramContext, 
+    ParameterBindingContext* paramContext,
+    ParameterBindingAndKindInfo& globalConstantBinding,
     TargetRequest* targetReq,
     DiagnosticSink* sink)
 {
@@ -3655,6 +3656,17 @@ static void _maybeApplyHLSLToVulkanShifts(
         return;
     }
 
+    // If the user specified -fvk-b-shift for the default space but not -fvk-bind-global, we want to apply the shift
+    // to the global constant buffer.
+    if (!vulkanOptions->hasGlobalsBinding())
+    {
+        auto globalCBufferShift = vulkanOptions->getShift(HLSLToVulkanLayoutOptions::Kind::ConstantBuffer, globalConstantBinding.space);
+        if (globalCBufferShift != HLSLToVulkanLayoutOptions::kInvalidShift)
+        {
+            globalConstantBinding.index += globalCBufferShift;
+        }
+    }
+
     for (ParameterInfo* parameterInfo : sharedContext.parameters)
     {
         auto varLayout = parameterInfo->varLayout;
@@ -4035,7 +4047,7 @@ RefPtr<ProgramLayout> generateParameterBindings(
     _completeBindings(&context, program);
 
     // We may need to finally do any shifting if we have HLSLToVulkanLayoutOptions
-    _maybeApplyHLSLToVulkanShifts(&context, targetReq, sink);
+    _maybeApplyHLSLToVulkanShifts(&context, globalConstantBufferBinding, targetReq, sink);
 
     // Next we need to create a type layout to reflect the information
     // we have collected, and we will use the `ScopeLayoutBuilder`
diff --git a/tests/bindings/hlsl-to-vulkan-shift-bshift-global.slang b/tests/bindings/hlsl-to-vulkan-shift-bshift-global.slang
new file mode 100644
index 000000000..5972805e9
--- /dev/null
+++ b/tests/bindings/hlsl-to-vulkan-shift-bshift-global.slang
@@ -0,0 +1,35 @@
+//TEST:SIMPLE(filecheck=CHECK):-target glsl -profile glsl_450 -entry MainVs -stage vertex -fvk-b-shift 14 0 -fvk-s-shift 58 0 -fvk-t-shift 218 0 -fvk-u-shift 482 0
+
+// CHECK: layout(binding = 15)
+// CHECK-NEXT: layout(std140) uniform
+// CHECK-NEXT: {
+// CHECK-NEXT: vec4 g_vCBuffer0Values
+
+// CHECK: layout(binding = 14)
+// CHECK-NEXT: layout(std140) uniform
+// CHECK-NEXT: {
+// CHECK-NEXT: vec4 g_vGlobalValues
+
+float4 g_vGlobalValues; // This ends up in globals
+
+cbuffer CBufferTest_t 
+{
+	float4 g_vCBuffer0Values;
+};
+
+struct VS_INPUT
+{
+	float3 vPositionWs : POSITION;
+};
+
+struct PS_INPUT
+{
+	float4 vColor;
+};
+
+PS_INPUT MainVs( VS_INPUT i )
+{
+	PS_INPUT o;
+	o.vColor.rgba = g_vCBuffer0Values + g_vGlobalValues;
+	return o;
+}
\ No newline at end of file
diff --git a/tests/bindings/hlsl-to-vulkan-shift-rw-structured.hlsl b/tests/bindings/hlsl-to-vulkan-shift-rw-structured.hlsl
index 95e9ff3f7..2fcbdf77c 100644
--- a/tests/bindings/hlsl-to-vulkan-shift-rw-structured.hlsl
+++ b/tests/bindings/hlsl-to-vulkan-shift-rw-structured.hlsl
@@ -1,10 +1,16 @@
 //TEST:SIMPLE(filecheck=CHECK):-target glsl -profile glsl_450 -entry MainCs -stage compute  -fvk-b-shift 0 0 -fvk-s-shift 14 0 -fvk-t-shift 30 0 -fvk-u-shift 158 0
 
+
+// CHECK: layout(std430, binding = 159) buffer  
+// CHECK: } g_ByteBuffer
+
 // CHECK: layout(std430, binding = 158) buffer  
 
 RWStructuredBuffer<uint> g_OutputCullBits;
+RWByteAddressBuffer g_ByteBuffer;
+
 [numthreads(32, 1, 1)]
 void MainCs(uint3 vThreadId : SV_DispatchThreadID, uint3 vGroupThreadId : SV_GroupThreadID, uint3 vGroupId : SV_GroupID)
 {
-    g_OutputCullBits[vThreadId.x] = 0;
+    g_OutputCullBits[vThreadId.x] = g_ByteBuffer.Load(0);
 }
\ No newline at end of file
diff --git a/tests/bugs/vk-shift-uniform-issue.slang b/tests/bugs/vk-shift-uniform-issue.slang
index 950a01c6f..fa49c3561 100644
--- a/tests/bugs/vk-shift-uniform-issue.slang
+++ b/tests/bugs/vk-shift-uniform-issue.slang
@@ -24,7 +24,7 @@
 // CHECK:layout(binding = 1001)
 // CHECK:layout(std140) uniform _S4
 
-// CHECK:layout(binding = 0)
+// CHECK:layout(binding = 1000)
 // CHECK:layout(std140) uniform _S5
 
 Texture2D texture0;