Add query for per-thread properties when shader debugging

* This is distinct from input values or builtins because they're entirely
  internal for configuring the workgroup

renderdoc/driver/shaders/spirv/spirv_debug.h

@@ -44,6 +44,18 @@ enum class GatherChannel : uint8_t
   Alpha = 3,
 };
 
+enum class ThreadProperty : uint32_t
+{
+  Helper,
+  QuadId,
+  QuadLane,
+  Active,
+  Elected,
+  Count,
+};
+
+ITERABLE_OPERATORS(ThreadProperty);
+
 struct ThreadState;
 
 class DebugAPIWrapper
@@ -72,6 +84,8 @@ public:
   virtual void FillInputValue(ShaderVariable &var, ShaderBuiltin builtin, uint32_t threadIndex,
                               uint32_t location, uint32_t component) = 0;
 
+  virtual uint32_t GetThreadProperty(uint32_t threadIndex, ThreadProperty prop) = 0;
+
   enum TextureType
   {
     Float_Texture = 0x00,

renderdoc/driver/vulkan/vk_shaderdebug.cpp

@@ -544,6 +544,16 @@ public:
            threadIndex, location, component);
   }
 
+  uint32_t GetThreadProperty(uint32_t threadIndex, rdcspv::ThreadProperty prop) override
+  {
+    if(prop >= rdcspv::ThreadProperty::Count)
+      return 0;
+    if(threadIndex >= thread_props.size())
+      return 0;
+
+    return thread_props[threadIndex][(size_t)prop];
+  }
+
   bool CalculateSampleGather(rdcspv::ThreadState &lane, rdcspv::Op opcode,
                              DebugAPIWrapper::TextureType texType, ShaderBindIndex imageBind,
                              ShaderBindIndex samplerBind, const ShaderVariable &uv,
@@ -1456,6 +1466,8 @@ public:
   // per-thread custom inputs by location [thread][location]
   rdcarray<rdcarray<ShaderVariable>> location_inputs;
 
+  rdcarray<rdcfixedarray<uint32_t, arraydim<rdcspv::ThreadProperty>()>> thread_props;
+
 private:
   WrappedVulkan *m_pDriver = NULL;
   ShaderDebugData &m_DebugData;