[PATCH] D24083: [CMake] Fix libc++abi __aeabi_idiv() link error.
logan added a comment. Sorry, I don't have time to work on this recently. Here's the plan: 1. Add another flag to specify the path to `libclang_rt-builtin.a`. 2. If that flag was not specified and the compiler is `clang`, then run `clang -###` to extract for `-L` option and `-l` option for `libclang_rt-builtin.a`. 3. If neither (1) nor (2) are available, then report an error. I hope I can get back to this next week. https://reviews.llvm.org/D24083 ___ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[PATCH] D24083: [CMake] Fix libc++abi __aeabi_idiv() link error.
rengolin added a comment. Was this abandoned? Merged? https://reviews.llvm.org/D24083 ___ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[PATCH] D24083: [CMake] Fix libc++abi __aeabi_idiv() link error.
rengolin added a comment.
In https://reviews.llvm.org/D24083#534464, @EricWF wrote:
> In https://reviews.llvm.org/D24083#534459, @logan wrote:
>
> > One solution might be adding the `libclang_rt.builtins.${arch}.a` detection
> > rules[1] to CMakeLists.txt, and manually specify
> > `-lclang_rt.builtins-${arch}.a` when `LIBCXXABI_USE_COMPILER_RT` is
> > enabled. How do you think about this solution?
>
>
> That SGTM. There's a similar workaround in libc++ to link the sanitizer
> run-times on OS X (found here
> ).
+1
https://reviews.llvm.org/D24083
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Re: [PATCH] D24083: [CMake] Fix libc++abi __aeabi_idiv() link error.
EricWF added a comment.
In https://reviews.llvm.org/D24083#534459, @logan wrote:
> One solution might be adding the `libclang_rt.builtins.${arch}.a` detection
> rules[1] to CMakeLists.txt, and manually specify
> `-lclang_rt.builtins-${arch}.a` when `LIBCXXABI_USE_COMPILER_RT` is enabled.
> How do you think about this solution?
That SGTM. There's a similar workaround in libc++ to link the sanitizer
run-times on OS X (found here
).
https://reviews.llvm.org/D24083
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Re: [PATCH] D24083: [CMake] Fix libc++abi __aeabi_idiv() link error.
logan added a comment.
Hi @rengolin and @EricWF,
After tracing the commit log of clang, it seems that `--rtlib=` is ignored
intentionally when `-nodefaultlibs` is present. (see also:
https://reviews.llvm.org/rL254535)
And, unfortunately, we don't have a command line option to ask clang to link
compiler-rt built-in library along (regardless the `-nodefaultlibs` option.)
One solution might be adding the `libclang_rt.builtins.${arch}.a` detection
rules[1] to CMakeLists.txt, and manually specify
`-lclang_rt.builtins-${arch}.a` when `LIBCXXABI_USE_COMPILER_RT` is enabled.
How do you think about this solution?
[1] There is a function named `ToolChain::getCompilerRT()` in
`${clang}/lib/Driver/ToolChain.cpp` which is responsible to detect and pick the
correct compiler-rt library.
https://reviews.llvm.org/D24083
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Re: [PATCH] D24083: [CMake] Fix libc++abi __aeabi_idiv() link error.
EricWF added a comment. This is not correct. We need the `-nodefaultlibs` on most platforms to prevent libstdc++ from being linked. I think the correct fix is to change `--rtlib=` https://reviews.llvm.org/D24083 ___ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
Re: [PATCH] D24083: [CMake] Fix libc++abi __aeabi_idiv() link error.
rengolin added a comment. This looks like a work around the fact that --rtlib is being ignored with --nodefaultlibs. I'm not sure that's a sane behaviour, if you explicitly specify --rtlib. https://reviews.llvm.org/D24083 ___ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[PATCH] D24083: [CMake] Fix libc++abi __aeabi_idiv() link error.
logan created this revision. logan added reviewers: mclow.lists, rengolin, EricWF. logan added a subscriber: cfe-commits. Herald added a subscriber: aemerson. This commit fixes __aeabi_idiv() link error when we are building libc++abi with compiler-rt. When compiler-rt is enabled, the option `--rtlib=compiler-rt` will be added to link flags. However, if `-nodefaultlibs` is specified simultaneously, `--rtlib` will be ignored and compiler-rt libraries will not be linked. Consequently, several ARM built-in functions, e.g. __aeabi_idiv(), will not be available. https://reviews.llvm.org/D24083 Files: src/CMakeLists.txt Index: src/CMakeLists.txt === --- src/CMakeLists.txt +++ src/CMakeLists.txt @@ -70,7 +70,9 @@ # Setup flags. append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_FPIC_FLAG -fPIC) -append_if(LIBCXXABI_LINK_FLAGS LIBCXXABI_HAS_NODEFAULTLIBS_FLAG -nodefaultlibs) +if (NOT LIBCXXABI_USE_COMPILER_RT) + append_if(LIBCXXABI_LINK_FLAGS LIBCXXABI_HAS_NODEFAULTLIBS_FLAG -nodefaultlibs) +endif() set(LIBCXXABI_SHARED_LINK_FLAGS) Index: src/CMakeLists.txt === --- src/CMakeLists.txt +++ src/CMakeLists.txt @@ -70,7 +70,9 @@ # Setup flags. append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_FPIC_FLAG -fPIC) -append_if(LIBCXXABI_LINK_FLAGS LIBCXXABI_HAS_NODEFAULTLIBS_FLAG -nodefaultlibs) +if (NOT LIBCXXABI_USE_COMPILER_RT) + append_if(LIBCXXABI_LINK_FLAGS LIBCXXABI_HAS_NODEFAULTLIBS_FLAG -nodefaultlibs) +endif() set(LIBCXXABI_SHARED_LINK_FLAGS) ___ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
