[TEMP] MSVC: Try LLVM's built-in weak-any implementation starting with LLVM 13

Author: kinke

gen/functions.cpp

@@ -944,8 +944,9 @@ bool eraseDummyAfterReturnBB(llvm::BasicBlock *bb) {
   return false;
 }
 
+#if LDC_LLVM_VER < 1300
 /**
- * LLVM doesn't really support weak linkage for MSVC targets, it just prevents
+ * (Old) LLVM doesn't really support weak linkage for MSVC targets, it just prevents
  * inlining. We can emulate it though, by conceptually renaming the defined
  * function, only declaring the original function and embedding a linker
  * directive in the object file, instructing the linker to fall back to the weak
@@ -999,6 +1000,7 @@ void emulateWeakAnyLinkageForMSVC(LLFunction *func, LINK linkage) {
   setLinkage({LLGlobalValue::ExternalLinkage, false}, func);
   func->deleteBody();
 }
+#endif // LDC_LLVM_VER < 1300
 
 } // anonymous namespace
 
@@ -1376,11 +1378,13 @@ void DtoDefineFunction(FuncDeclaration *fd, bool linkageAvailableExternally) {
     gIR->dcomputetarget->addKernelMetadata(fd, fn);
   }
 
+#if LDC_LLVM_VER < 1300
   if (func->getLinkage() == LLGlobalValue::WeakAnyLinkage &&
       !func->hasDLLExportStorageClass() &&
       global.params.targetTriple->isWindowsMSVCEnvironment()) {
     emulateWeakAnyLinkageForMSVC(func, fd->linkage);
   }
+#endif
 }
 
 ////////////////////////////////////////////////////////////////////////////////