Migrating back to using UniformBuffer structs.

Since the cbuffer uses the same name as the struct, we have to rename the cbuffer using a consistent prefix. The reflection handling also needs to reinterpret the renamed cbuffer as the correct UniformBuffer.

#jira none
#rb kenzo.terelst
#preflight 625edc5f034d8924cdcc35e2

[CL 19813742 by christopher waters in ue5-main branch]

Engine/Source/Developer/ShaderCompilerCommon/Private/ShaderCompilerCommon.cpp

@@ -5,6 +5,7 @@
 #include "Modules/ModuleManager.h"
 #include "HlslccDefinitions.h"
 #include "HAL/FileManager.h"
+#include "ShaderParameters.h"
 
 IMPLEMENT_MODULE(FDefaultModuleImpl, ShaderCompilerCommon);
 
@@ -469,6 +470,13 @@ TCHAR* FindNextUniformBufferReference(TCHAR* SearchPtr, const TCHAR* SearchStrin
 	return nullptr;
 }
 
+FString UE::ShaderCompilerCommon::SanitizeUniformBufferName(const FString& InName)
+{
+	FString NewName(InName);
+	NewName.RemoveFromStart(UE::ShaderParameters::kUniformBufferConstantBufferPrefix);
+	return NewName;
+}
+
 void HandleReflectedGlobalConstantBufferMember(
 	const FString& MemberName,
 	uint32 ConstantBufferIndex,
@@ -518,8 +526,10 @@ void HandleReflectedUniformBuffer(
 	FShaderCompilerOutput& CompilerOutput
 )
 {
+	FString AdjustedUniformBufferName(UE::ShaderCompilerCommon::SanitizeUniformBufferName(UniformBufferName));
+
 	CompilerOutput.ParameterMap.AddParameterAllocation(
-		*UniformBufferName,
+		*AdjustedUniformBufferName,
 		ReflectionSlot,
 		BaseIndex,
 		BufferSize,