Hi, on 2021/7/5 上午1:31, NightStrike via Gcc-help wrote: > Which of these is correct? > IIUC the quoted content in gcc-11 changes is stale and wrong. Good catch! > 1) The manual states: > > used > > This attribute, attached to a variable with static storage, means that > the variable must be emitted even if it appears that the variable is > not referenced. > > When applied to a static data member of a C++ class template, the > attribute also means that the member is instantiated if the class > itself is instantiated. > > retain > > For ELF targets that support the GNU or FreeBSD OSABIs, this attribute > will save the variable from linker garbage collection. To support this > behavior, variables that have not been placed in specific sections > (e.g. by the section attribute, or the -fdata-sections option), will > be placed in new, unique sections. > > This additional functionality requires Binutils version 2.36 or later. > > > > > 2) The gcc 11 changes website (https://gcc.gnu.org/gcc-11/changes.html) states: > > For ELF targets that support the GNU or FreeBSD OSABIs, the used > attribute will now save the symbol declaration it is applied to from > linker garbage collection. > > To support this behavior, used symbols that have not been placed in > specific sections (e.g. with the section attribute, or the > -f{function,data}-sections options) will be placed in new, unique > sections. > > This functionality requires Binutils version 2.36 or later. > The above note was meant for the change introduced by commit [1]. But later commit [2] introduced attribute "retain" and recovered the behavior of attribute "used". So I'm afraid that the above note has to be removed to avoid any confusions. CC Jozef. BR, Kewen [1] https://gcc.gnu.org/git/gcc.git/6fbec038f7a7ddf29f074943611b53210d17c40c [2] https://gcc.gnu.org/git/gcc.git/6347f4a0904fce17eedf5c071be6f3c118680290
