There's an issue with LLVM metadata support; it triggers an assert when trying to generate asm for code with metadata globals. This new pass is used as a workaround: it strips metadata from the module before it reaches the code generator. Obviously, this is disabled if LLVM doesn't support metadata.

#ifndef LDC_GEN_METADATA_H
#define LDC_GEN_METADATA_H

#include "gen/llvm-version.h"

#if LLVM_REV >= 68420
#  define USE_METADATA
#  define METADATA_LINKAGE_TYPE  llvm::GlobalValue::WeakODRLinkage
#endif

#endif