search for: can_be_hidden

...n Wu <stevenwu at apple.com> writes: > I did a bit more digging for the auto hide problem. Here is my finding that prevent us from doing this by default in GlobalOpts > > 1. When a symbol is linkonce_odr hidden unnamed_addr, it emits both '.private_extern' and '.weak_def_can_be_hidden' asm directives on macho platform. There result of that is .private_extern will win so this is essentially linkonce_odr hidden. What do those directives mean? I assume .weak_def_can_be_hidden is the "you can drop this from the symbol table", but .private_extern I am not sure. > 2...

I did a bit more digging for the auto hide problem. Here is my finding that prevent us from doing this by default in GlobalOpts 1. When a symbol is linkonce_odr hidden unnamed_addr, it emits both '.private_extern' and '.weak_def_can_be_hidden' asm directives on macho platform. There result of that is .private_extern will win so this is essentially linkonce_odr hidden. 2. ld64 does treat these two type of symbols differently. For example, ld64 will deduplicate all the can_be_hidden symbols to reduce code size. This can't be achie...

Interesting. Now I understand the full picture. For MachO, linker is picking based on atoms so it picks the atom with more visibility which doesn’t have the constraint you mentioned. Let me do some more digging. Worst case I will add a different rule for MachO but it might be fine. Steven > On Feb 9, 2018, at 1:40 PM, Rafael Avila de Espindola <rafael.espindola at gmail.com> wrote: >

...at apple.com> writes: > >> I did a bit more digging for the auto hide problem. Here is my finding that prevent us from doing this by default in GlobalOpts >> >> 1. When a symbol is linkonce_odr hidden unnamed_addr, it emits both '.private_extern' and '.weak_def_can_be_hidden' asm directives on macho platform. There result of that is .private_extern will win so this is essentially linkonce_odr hidden. > > What do those directives mean? I assume .weak_def_can_be_hidden is the > "you can drop this from the symbol table", but .private_extern I am no...

...writes: >> >>> I did a bit more digging for the auto hide problem. Here is my finding that prevent us from doing this by default in GlobalOpts >>> >>> 1. When a symbol is linkonce_odr hidden unnamed_addr, it emits both '.private_extern' and '.weak_def_can_be_hidden' asm directives on macho platform. There result of that is .private_extern will win so this is essentially linkonce_odr hidden. >> >> What do those directives mean? I assume .weak_def_can_be_hidden is the >> "you can drop this from the symbol table", but .private_ex...

...lvm-dev at lists.llvm.org> wrote: > > I did a bit more digging for the auto hide problem. Here is my finding that prevent us from doing this by default in GlobalOpts > > 1. When a symbol is linkonce_odr hidden unnamed_addr, it emits both '.private_extern' and '.weak_def_can_be_hidden' asm directives on macho platform. There result of that is .private_extern will win so this is essentially linkonce_odr hidden. > 2. ld64 does treat these two type of symbols differently. For example, ld64 will deduplicate all the can_be_hidden symbols to reduce code size. This can't be...

...; wrote: > > > > I did a bit more digging for the auto hide problem. Here is my finding > that prevent us from doing this by default in GlobalOpts > > > > 1. When a symbol is linkonce_odr hidden unnamed_addr, it emits both > '.private_extern' and '.weak_def_can_be_hidden' asm directives on macho > platform. There result of that is .private_extern will win so this is > essentially linkonce_odr hidden. > > 2. ld64 does treat these two type of symbols differently. For example, > ld64 will deduplicate all the can_be_hidden symbols to reduce code size...

...;> >>>> I did a bit more digging for the auto hide problem. Here is my finding that prevent us from doing this by default in GlobalOpts >>>> >>>> 1. When a symbol is linkonce_odr hidden unnamed_addr, it emits both '.private_extern' and '.weak_def_can_be_hidden' asm directives on macho platform. There result of that is .private_extern will win so this is essentially linkonce_odr hidden. >>> >>> What do those directives mean? I assume .weak_def_can_be_hidden is the >>> "you can drop this from the symbol table", but...