MC Layer Target

Target

Every type of backends stay MC Chengdu will have a corresponding Target class , position On llvm\include\llvm\MC\TargetRegistry.h file .

• Target Contains the corresponding backends Some basic information about
• Every backend There will be a single instance Target
• Target In addition to containing some basic information , Another important use ： Create for MC The classes in the layer provide createXXX Interface , Therefore use MC You need to call Target in createXX Interface Create the appropriate MC Components
• For example, when disassembling, you need to call createMCDisassembler, establish MCDisassembler Disassembly .

Target member

Target Members are mainly divided into two parts ： Basic information members and various callback functions

• Basic information members , for example const char *Name、const char *BackendName Wait and so on .
• Various callback functions Fn, for example MCAsmInfoCtorFn etc. ,XXXXFn With Fn Mainly createXXXX Interface to create the corresponding MC Components used in ,

XXXXFn You need to call the corresponding... At startup registerXXX Function to register ,TargetRegistry.h Various register function Provide XXXFn Registration function .

TargetRegistry.h Various creareXXXX function , Used to create MC Various components in .

FirstTarget

All registered backend Target It will eventually be connected in series in the form of a one-way linked list ：

FirstTarget Register for the first Target, Look for a Target One way linked list cyclic access is required , At present due to backend Not many , Therefore, one-way linked list can meet the demand .

<Target>TargetInfo.cpp

When you add a back-end, it usually creates a corresponding <Target>TargetInfo.cpp file , Used to provide corresponding Target Class single instance and registration function

AMDGPU MC Target The registration function is located at llvm\lib\Target\AMDGPU\TargetInfo\AMDGPUTargetInfo.cpp In file ：

Provide R600 and GCN Two Target Single instance registration function .

TargetRegistry::RegisterTarget

TargetRegistry::RegisterTarget Finally, the single instance Target Sign up to RegisterTarget In a one-way list ：