[BOLT][DWARF][NFC] Move Arch assignment out of createBinaryContext (#102054)

Moves the assignment of Arch out of createBinaryContext to prevent data
races when parallelized.

bolt/lib/Core/BinaryContext.cpp

@@ -142,7 +142,6 @@ BinaryContext::BinaryContext(std::unique_ptr<MCContext> Ctx,
       InstPrinter(std::move(InstPrinter)), MIA(std::move(MIA)),
       MIB(std::move(MIB)), MRI(std::move(MRI)), DisAsm(std::move(DisAsm)),
       Logger(Logger), InitialDynoStats(isAArch64()) {
-  Relocation::Arch = this->TheTriple->getArch();
   RegularPageSize = isAArch64() ? RegularPageSizeAArch64 : RegularPageSizeX86;
   PageAlign = opts::NoHugePages ? RegularPageSize : HugePageSize;
 }

bolt/lib/Rewrite/MachORewriteInstance.cpp

@@ -72,6 +72,7 @@ MachORewriteInstance::MachORewriteInstance(object::MachOObjectFile *InputFile,
                                            StringRef ToolPath, Error &Err)
     : InputFile(InputFile), ToolPath(ToolPath) {
   ErrorAsOutParameter EAO(&Err);
+  Relocation::Arch = InputFile->makeTriple().getArch();
   auto BCOrErr = BinaryContext::createBinaryContext(
       InputFile->makeTriple(), InputFile->getFileName(), nullptr,
       /* IsPIC */ true, DWARFContext::create(*InputFile),

bolt/lib/Rewrite/RewriteInstance.cpp

@@ -354,6 +354,7 @@ RewriteInstance::RewriteInstance(ELFObjectFileBase *File, const int Argc,
     }
   }
 
+  Relocation::Arch = TheTriple.getArch();
   auto BCOrErr = BinaryContext::createBinaryContext(
       TheTriple, File->getFileName(), Features.get(), IsPIC,
       DWARFContext::create(*File, DWARFContext::ProcessDebugRelocations::Ignore,

bolt/unittests/Core/BinaryContext.cpp

@@ -46,6 +46,7 @@ protected:
   }
 
   void initializeBOLT() {
+    Relocation::Arch = ObjFile->makeTriple().getArch();
     BC = cantFail(BinaryContext::createBinaryContext(
         ObjFile->makeTriple(), ObjFile->getFileName(), nullptr, true,
         DWARFContext::create(*ObjFile.get()), {llvm::outs(), llvm::errs()}));

bolt/unittests/Core/MCPlusBuilder.cpp

@@ -56,6 +56,7 @@ protected:
   }
 
   void initializeBolt() {
+    Relocation::Arch = ObjFile->makeTriple().getArch();
     BC = cantFail(BinaryContext::createBinaryContext(
         ObjFile->makeTriple(), ObjFile->getFileName(), nullptr, true,
         DWARFContext::create(*ObjFile.get()), {llvm::outs(), llvm::errs()}));