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These linkages were introduced some time ago, but it was never very clear what exactly their semantics were or what they should be used for. Some investigation found these uses: * utf-16 strings in clang. * non-unnamed_addr strings produced by the sanitizers. It turns out they were just working around a more fundamental problem. For some sections a MachO linker needs a symbol in order to split the section into atoms, and llvm had no idea that was the case. I fixed that in r201700 and it is now safe to use the private linkage. When the object ends up in a section that requires symbols, llvm will use a 'l' prefix instead of a 'L' prefix and things just work. With that, these linkages were already dead, but there was a potential future user in the objc metadata information. I am still looking at CGObjcMac.cpp, but at this point I am convinced that linker_private and linker_private_weak are not what they need. The objc uses are currently split in * Regular symbols (no '\01' prefix). LLVM already directly provides whatever semantics they need. * Uses of a private name (start with "\01L" or "\01l") and private linkage. We can drop the "\01L" and "\01l" prefixes as soon as llvm agrees with clang on L being ok or not for a given section. I have two patches in code review for this. * Uses of private name and weak linkage. The last case is the one that one could think would fit one of these linkages. That is not the case. The semantics are * the linker will merge these symbol by *name*. * the linker will hide them in the final DSO. Given that the merging is done by name, any of the private (or internal) linkages would be a bad match. They allow llvm to rename the symbols, and that is really not what we want. From the llvm point of view, these objects should really be (linkonce|weak)(_odr)?. For now, just keeping the "\01l" prefix is probably the best for these symbols. If we one day want to have a more direct support in llvm, IMHO what we should add is not a linkage, it is just a hidden_symbol attribute. It would be applicable to multiple linkages. For example, on weak it would produce the current behavior we have for objc metadata. On internal, it would be equivalent to private (and we should then remove private). llvm-svn: 203866 |
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| llvm.vim | ||
| README | ||
| tablegen.vim | ||
| vimrc | ||
-*- llvm/utils/vim/README -*-
These are syntax highlighting files for the VIM editor. Included are:
* llvm.vim
Syntax highlighting mode for LLVM assembly files. To use, copy `llvm.vim' to
~/.vim/syntax and add this code to your ~/.vimrc :
augroup filetype
au! BufRead,BufNewFile *.ll set filetype=llvm
augroup END
* tablegen.vim
Syntax highlighting mode for TableGen description files. To use, copy
`tablegen.vim' to ~/.vim/syntax and add this code to your ~/.vimrc :
augroup filetype
au! BufRead,BufNewFile *.td set filetype=tablegen
augroup END
If you prefer, instead of making copies you can make symlinks from
~/.vim/syntax/... to the syntax files in your LLVM source tree. Apparently
this did not work with older versions of vim however, so if this doesn't
work you may need to make actual copies of the files.
Another option, if you do not already have a ~/.vim/syntax directory, is
to symlink ~/.vim/syntax itself to llvm/utils/vim .
Note: If you notice missing or incorrect syntax highlighting, please contact
<llvmbugs [at] cs.uiuc.edu>; if you wish to provide a patch to improve the
functionality, it will be most appreciated. Thank you.
If you find yourself working with LLVM Makefiles often, but you don't get syntax
highlighting (because the files have names such as Makefile.rules or
TEST.nightly.Makefile), add the following to your ~/.vimrc:
" LLVM Makefile highlighting mode
augroup filetype
au! BufRead,BufNewFile *Makefile* set filetype=make
augroup END