lld 21.0.0git Release Notes¶
Warning
These are in-progress notes for the upcoming LLVM 21.0.0git release. Release notes for previous releases can be found on the Download Page.
Introduction¶
This document contains the release notes for the lld linker, release 21.0.0git. 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¶
For AArch64, added support for
-zgcs-report-dynamic, enabling checks for GNU GCS Attribute Flags in Dynamic Objects when GCS is enabled. Inherits value from-zgcs-report(capped atwarninglevel) unless user-defined, ensuring compatibility with GNU ld linker.The default Hexagon architecture version in ELF object files produced by lld is changed to v68. This change is only effective when the version is not provided in the command line by the user and cannot be inferred from inputs.
--why-live=<glob>prints for each symbol matching<glob>a chain of items that kept it live during garbage collection. This is inspired by the Mach-O LLD feature of the same name.Linker script
OVERLAYdescriptions now support virtual memory regions (e.g.>region) andNOCROSSREFS.Added
--xosegmentand--no-xosegmentflags to control whether to place executable-only and readable-executable sections in the same segment. The default value is--no-xosegment. (#132412)For AArch64, added support for the
SHF_AARCH64_PURECODEsection flag, which indicates that the section only contains program code and no data. An output section will only have this flag set if all input sections also have it set. (#125689, #134798)For AArch64 and ARM, added
-zexecute-only-report, which checks for missingSHF_AARCH64_PURECODEandSHF_ARM_PURECODEsection flags on executable sections. (#128883)
Breaking changes¶
Executable-only and readable-executable sections are now allowed to be placed in the same segment by default. Pass
--xosegmentto lld in order to get the old behavior back.When using
--no-piewithout aSECTIONScommand, the linker uses the target’s default image base. If-Ttext=or--section-startspecifies an output section address below this base, there will now be an error.--image-basecan be set at a lower address to fix the error. (#140187)