[llvm-dev] Should we switch to --hash-style=both by default in LLD ?

[George Rimar via llvm-dev]

Hi !

During linking LLD and other linkers builds a static hash table for dynamic symbols,
so that in runtime dynamic linker can use this table and find symbols faster.

--hash-style=style linker option is used to select the hash type:
"Set the type of linker's hash table(s). style can be either "sysv" for classic ELF ".hash" section, 
"gnu" for new style GNU ".gnu.hash" section or "both" for both the classic ELF ".hash" and new
style GNU ".gnu.hash" hash tables. The default is "sysv"."

GNU_HASH format is a better version of hash table (https://sourceware.org/ml/binutils/2006-10/msg00377.html).

We have --hash-style=sysv currently set by default in LLD. 
Though recently (see https://bugs.llvm.org//show_bug.cgi?id=34712) GNU linkers switched to use
".gnu.hash" section format in addition to normally used classic ".hash". 
So they defaults --hash-style to "both" and this looks to be released with binutils 2.30.

I think we can switch LLD either to "both" or probably to "gnu" by default as well.
Initial version of patch that changes default to "both" is here: D38407

Any thoughts ?

Best regards,
George | Developer | Access Softek, Inc