[llvm-dwarfutil] Remove unnecessarily dependency.

[avl]

Summary

llvm-dwarutil.cpp unnecessarily call to InitializeAllAsmParsers.
That call might be removed as well as dependency on ${LLVM_TARGETS_TO_BUILD}

[thakis]

Thanks! I'm not an expert in this area, so the below might be silly questions. Apologies in advance :)

llvm/tools/llvm-dwarfutil/CMakeLists.txt

6

Given that you call InitializeAllTargets(), shouldn't you keep this one and instead remove the 3 AllTargetsFoo at the bottom instead?

(InitializeAllTargets calls LLVMInitialize.*Target\b and that's in llvm/lib/Target/Foo/FooTargetMachine.cpp)

llvm/tools/llvm-dwarfutil/llvm-dwarfutil.cpp

484

It's not obvious to me why this call is redundant, can you elaborate?

[avl]

llvm/tools/llvm-dwarfutil/CMakeLists.txt

6

${LLVM_TARGETS_TO_BUILD} includes wider set of dependencies.
If tool does not need f.e. disassembler then we can remove corresponding dependency.
In this concrete case FooDisassembler, FooAsmParser are not neccessary.

If 3 AllTargetsFoo would be removed and ${LLVM_TARGETS_TO_BUILD} will be left then dependency on AllTargetsDisassemblers and others would be added.

llvm/tools/llvm-dwarfutil/llvm-dwarfutil.cpp

484

AsmParser functionality is not used by this tool. Thus we do not need to initialize them.

[thakis]

s/redundantly/unnecessarily/ in commit description then, maybe?

[thakis]

I meant "redundantly calls" -> "unnecessarily calls".

In the title it should be "Remove unnecessary dependency", without "-ly" :)

[avl]

@thakis Thank you for the review!

llvm/tools/llvm-dwarfutil/CMakeLists.txt

 set(LLVM_TARGET_DEFINITIONS Options.td)
 tablegen(LLVM Options.inc -gen-opt-parser-defs)
 add_public_tablegen_target(DwarfutilTableGen)
 
 set(LLVM_LINK_COMPONENTS
-  ${LLVM_TARGETS_TO_BUILD}
   DebugInfoDWARF
   DWARFLinker
   MC
   ObjCopy
   Object
   Option
   Support
   Target

llvm/tools/llvm-dwarfutil/llvm-dwarfutil.cpp

int main(int Argc, char const *Argv[]) {
   Options Opts;
   if (Error Err = validateAndSetOptions(Args, Opts))
     error(std::move(Err), dwarfutil::ToolName);
 
   InitializeAllTargets();
   InitializeAllTargetMCs();
   InitializeAllTargetInfos();
   InitializeAllAsmPrinters();
-  InitializeAllAsmParsers();
 
   ErrorOr<std::unique_ptr<MemoryBuffer>> BuffOrErr =
       MemoryBuffer::getFileOrSTDIN(Opts.InputFileName);
   if (BuffOrErr.getError())
     error(createFileError(Opts.InputFileName, BuffOrErr.getError()));
 
   Expected<std::unique_ptr<Binary>> BinOrErr =
       object::createBinary(**BuffOrErr);