lld 16.0.0 Release Notes

Introduction

This document contains the release notes for the lld linker, release 16.0.0. Here we describe the status of lld, including major improvements from the previous release. All lld releases may be downloaded from the LLVM releases web site.

Non-comprehensive list of changes in this release

ELF Improvements

  • Link speed improved greatly compared with lld 15.0. Notably input section initialization and relocation scanning are now parallel. (D130810) (D133003)

  • ELFCOMPRESS_ZSTD compressed input sections are now supported. (D129406)

  • --compress-debug-sections=zstd is now available to compress debug sections with zstd (ELFCOMPRESS_ZSTD). (D133548)

  • --no-warnings/-w is now available to suppress warnings. (D136569)

  • DT_RISCV_VARIANT_CC is now produced if at least one R_RISCV_JUMP_SLOT relocation references a symbol with the STO_RISCV_VARIANT_CC bit. (D107951)

  • DT_STATIC_TLS is now set for AArch64/PPC32/PPC64 initial-exec TLS models when producing a shared object.

  • --no-undefined-version is now the default; symbols named in version scripts that have no matching symbol in the output will be reported. Use --undefined-version to revert to the old behavior. (D135402)

  • -V is now an alias for -v to support gcc -fuse-ld=lld -v on many targets.

  • -r no longer defines __global_pointer$ or _TLS_MODULE_BASE_.

  • A corner case of mixed GCC and Clang object files (STB_WEAK and STB_GNU_UNIQUE in different COMDATs) is now supported. (D136381)

  • The output SHT_RISCV_ATTRIBUTES section now merges all input components instead of picking the first input component. (D138550)

  • For x86-32, -fno-plt GD/LD TLS models call *___tls_get_addr@GOT(%reg) are now supported. Previous output might have runtime crash.

  • Armv4(T) thunks are now supported. (D139888) (D141272)

COFF Improvements

  • The linker command line entry in S_ENVBLOCK of the PDB is now stripped from input files, to align with MSVC behavior. (D137723)

  • Switched from SHA1 to BLAKE3 for PDB type hashing / -gcodeview-ghash (D137101)

  • Improvements to the PCH.OBJ files handling. Now LLD behaves the same as MSVC link.exe when merging PCH.OBJ files that don’t have the same signature. (D136762)

  • Changed the OrdinalBase for DLLs from 0 to 1, matching the output from both MS link.exe and GNU ld. (D134140)

MinGW Improvements

  • The lld-specific options --guard-cf, --no-guard-cf, --guard-longjmp and --no-guard-longjmp has been added to allow enabling Control Flow Guard and long jump hardening. These options are disabled by default, but enabling --guard-cf will also enable --guard-longjmp unless --no-guard-longjmp is also specified. --guard-longjmp depends on --guard-cf and cannot be used by itself. Note that these features require the _load_config_used symbol to contain the load config directory and be filled with the required symbols. (D132808)

  • Pick up libraries named <name>.lib when linked with -l<name>, even if -static has been specified. This fixes conformance to what GNU ld does. (D135651)

  • Unwinding in Rust code on i386 in MinGW builds has been fixed, by avoiding to leave out the rust_eh_personality symbol. (D136879)