[M68k] Mark public functions with the LLVM_EXTERNAL_VISIBILITY macro

[glaubitz]

Summary

In 0dbcb3639451, most most target symbols were made hidden by default
with the public ones marked with LLVM_EXTERNAL_VISIBILITY. When the
M68k target was added, this particular change was forgotten so that
external tools cannot make use of the public M68k target functions
in libLLVM.so. Thus, add the missing LLVM_EXTERNAL_VISIBILITY macro
to all public target functions in the M68k backend.

[myhsu]

LGTM. Thanks
I don't think we need a second LGTM since this is a minor change

[glaubitz]

In D99869#2668549, @myhsu wrote:

LGTM. Thanks
I don't think we need a second LGTM since this is a minor change

Thanks. This was caught while working on the first Debian packages. Once this has been merged here, I can drop the patch in Debian again.

llvm/lib/Target/M68k/M68kAsmPrinter.cpp

 void M68kAsmPrinter::emitFunctionBodyEnd() {}
 
 void M68kAsmPrinter::emitStartOfAsmFile(Module &M) {
   OutStreamer->emitSyntaxDirective();
 }
 
 void M68kAsmPrinter::emitEndOfAsmFile(Module &M) {}
 
-extern "C" void LLVMInitializeM68kAsmPrinter() {
+extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeM68kAsmPrinter() {
   RegisterAsmPrinter<M68kAsmPrinter> X(getTheM68kTarget());
 }

llvm/lib/Target/M68k/M68kTargetMachine.cpp

 #include "llvm/IR/LegacyPassManager.h"
 #include "llvm/Support/TargetRegistry.h"
 #include <memory>
 
 using namespace llvm;
 
 #define DEBUG_TYPE "m68k"
 
-extern "C" void LLVMInitializeM68kTarget() {
+extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeM68kTarget() {
   RegisterTargetMachine<M68kTargetMachine> X(getTheM68kTarget());
 }
 
 namespace {
 
 std::string computeDataLayout(const Triple &TT, StringRef CPU,
                               const TargetOptions &Options) {
   std::string Ret = "";

llvm/lib/Target/M68k/MCTargetDesc/M68kMCTargetDesc.cpp

 static MCInstPrinter *createM68kMCInstPrinter(const Triple &T,
                                               unsigned SyntaxVariant,
                                               const MCAsmInfo &MAI,
                                               const MCInstrInfo &MII,
                                               const MCRegisterInfo &MRI) {
   return new M68kInstPrinter(MAI, MII, MRI);
 }
 
-extern "C" void LLVMInitializeM68kTargetMC() {
+extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeM68kTargetMC() {
   Target &T = getTheM68kTarget();
 
   // Register the MC asm info.
   RegisterMCAsmInfoFn X(T, createM68kMCAsmInfo);
 
   // Register the MC instruction info.
   TargetRegistry::RegisterMCInstrInfo(T, createM68kMCInstrInfo);
 

llvm/lib/Target/M68k/TargetInfo/M68kTargetInfo.cpp

 
 namespace llvm {
 Target &getTheM68kTarget() {
   static Target TheM68kTarget;
   return TheM68kTarget;
 }
 } // namespace llvm
 
-extern "C" void LLVMInitializeM68kTargetInfo() {
+extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeM68kTargetInfo() {
   RegisterTarget<Triple::m68k, /*HasJIT=*/true> X(
       getTheM68kTarget(), "m68k", "Motorola 68000 family", "M68k");
 }