UBT

Read the XML configuration files

Create the C++ dependency cache &generate  dependency files

ExternalExecution.cs::WriteUHTManifest

UnrealBuildTool.cs::Main

生成二进制文件

-Target=\"newUBTTest Win64 Development -Project=\\\"D:\\dev\\UBTTest\ewUBTTest\ewUBTTest.uproject\" -WaitMutex -FromMsBuild

BuildMode.cs::Build

UEBuildModuleCPP::Compile

SelectExecutor

ExternalExecution.cs::ExecuteHeaderToolIfNecessary

ParallelExecutor.cs::ExcuteActions

BuildMode.cs::CreateMakeFile

{D:\\dev\\UBTTest\ewUBTTest\ewUBTTest.uproject D:\\dev\\UBTTest\ewUBTTest\\Intermediate\\Build\\Win64\ewUBTTest\\Development\ewUBTTest.uhtmanifest -WarningsAsErrors}

Get DLLBinary、module of plugin、DependencyModules

UhtSession.cs::StepExport

LinkEnvironmentUEToolChain

Parse the command line arguments

CreateBinaryCompileEnvironment

Exporter.Delegate(this)（通过委托UHTMode导出）

ExecuteActions

UEBuildBinary::SetupBinaryLinkEnvironment

FindSharedPCHs

Run and Parse(运行UHT核心步骤)

Run UHT

Unreal Header Tool (UHT) 的核心会话对象，负责管理整个头文件处理和代码生成过程

UnrealHeaderToolMode.cs::Excute

UEBuildTarget.cs::Build

Run the output exporter

UhtCodeGenerator.cs::CodeGenerator

GetCompilerArguments

UEBuildBinary::Build

BuildMode.cs::Execute

Log System

CppConfigurationCppCompileEnvironment

Parse and build the targets

Generate the command line

UhtHeaderCodeGeneratorHFile.cs

Write the command line

ActionGraph.cs::ExecuteActions

Create and build the target

获取编译参数

UhtHeaderCodeGeneratorCppFile.cs

Grab the environment.

GatherDependencyModules

EnvironmentVariables

ModulesToGenerateHeadersFor

GetClArguments

ExecuteHeaderToolIfNecessary

VCCompileAction.cs

GatherOutputItems

makefile.bin

create Session

{D:\\dev\\UBTTest\ewUBTTest\\Intermediate\\Build\\Win64\ewUBTTest\\Development\\Makefile.bin}

VCToolChain.cs::CompileCPPFiles

处理器定义、路径、源文件、目标文件、链接参数

Create a QueuedAction instance for each action in the makefiles

Write() 序列化编译动作（如编译器路径、源文件、输出文件、包含路径、宏定义等）写入一个二进制流）