> On May 13, 2016, at 3:56 PM, Duncan P. N. Exon Smith <dexonsm...@apple.com> > wrote: > > Is this something that you need the linker to treat as "used", or just > something you don't want the compiler to drop? If the latter, > @llvm.compiler.used seems more appropriate.
Bitcode is actually not really used by the compiler during compilation and shouldn't really used by any part of the code. llvm.compiler.used then. New patch.
0001-Fix-embed-bitcode-linkage-type.patch
Description: Binary data
Steven > >> On 2016-May-13, at 14:01, Steven Wu <steve...@apple.com> wrote: >> >> Attach a patch using private linkage type and adding to llvm.used. I have to >> recreate llvm.used when embedding bitcode. I don't really like it but I >> don't have better solutions. >> Few other options: >> 1. Not allowing re-embedded bitcode will simplify the code a bit but not a >> lot. >> 2. Create a new "llvm.*.used" variable in llvm.metadata section. >> 3. Teach optimizer do not optimize away llvm.* variables. >> >> <0001-Fix-embed-bitcode-linkage-type.patch> >> >> Steven >> >>> On May 13, 2016, at 10:10 AM, Rafael Espíndola <rafael.espind...@gmail.com> >>> wrote: >>> >>> On 13 May 2016 at 13:02, Steven Wu <steve...@apple.com> wrote: >>>> Hi Rafael >>>> >>>> Thanks for notice this! That would definitely cause duplicated symbol >>>> error and I should definitely change that. >>>> Here is some background: >>>> ld64 in Xcode 7+ knows how to handle the embedded bitcode correctly but >>>> not the ones in earlier Xcode. The old ld64 will simply concatenate the >>>> bitcode files which is not the right thing to do. So there is a symbol >>>> generated at the place to prevent user to link the bitcode object file >>>> with old ld64 because older ld64 will fail and report duplicated symbols. >>>> I have a radar tracking to change the linkage type when upstream but I >>>> dropped the ball on that one. The correct thing to do is to make it >>>> internal and add to llvm.used. I will come up with a patch. >>> >>> Thank you so much! >>> >>> Cheers, >>> Rafael >> >
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