[MacPorts] #59983: ld64-latest at 274.2_2+llvm80+universal-llvm34 :dyld: Symbol not found: _lto_module_is_thinlto

[MacPorts]

#59983: ld64-latest at 274.2_2+llvm80+universal-llvm34 :dyld: Symbol not found:
_lto_module_is_thinlto
--------------------+----------------------
 Reporter:  kencu   |      Owner:  kencu
     Type:  defect  |     Status:  assigned
 Priority:  Normal  |  Milestone:
Component:  ports   |    Version:
 Keywords:          |       Port:  ld64
--------------------+----------------------
 While building libtapi on 10.6.8 using clang-3.7, the following link error
 occurs:
 {{{
 cd
 /opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_devel_libtapi/libtapi/work/build/tools/clang/utils/TableGen
 && /opt/local/bin/cmake -E cmake_link_script CMakeFiles/clang-
 tblgen.dir/link.txt --verbose=ON
 /opt/local/bin/clang++-mp-3.7  -Wno-unknown-warning-option -Werror
 =unguarded-availability-new -stdlib=libc++ -fPIC -fvisibility-inlines-
 hidden -Werror=date-time -Werror=unguarded-availability-new -std=c++11
 -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wmissing-
 field-initializers -pedantic -Wno-long-long -Wcovered-switch-default -Wno-
 class-memaccess -Wnon-virtual-dtor -Wdelete-non-virtual-dtor -Wstring-
 conversion -flto -fno-common -Woverloaded-virtual -Os    -DNDEBUG -arch
 x86_64 -mmacosx-version-min=10.6 -Wl,-search_paths_first
 -Wl,-headerpad_max_install_names -L/opt/local/lib
 -Wl,-headerpad_max_install_names -stdlib=libc++ -flto  -Wl,-dead_strip
 -Wl,-object_path_lto,/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_devel_libtapi/libtapi/work/build/tools/clang/utils/TableGen
 /./clang-tblgen-lto.o CMakeFiles/obj.clang-
 tblgen.dir/ClangASTNodesEmitter.cpp.o CMakeFiles/obj.clang-
 tblgen.dir/ClangAttrEmitter.cpp.o CMakeFiles/obj.clang-
 tblgen.dir/ClangCommentCommandInfoEmitter.cpp.o CMakeFiles/obj.clang-
 tblgen.dir/ClangCommentHTMLNamedCharacterReferenceEmitter.cpp.o
 CMakeFiles/obj.clang-tblgen.dir/ClangCommentHTMLTagsEmitter.cpp.o
 CMakeFiles/obj.clang-tblgen.dir/ClangDataCollectorsEmitter.cpp.o
 CMakeFiles/obj.clang-tblgen.dir/ClangDiagnosticsEmitter.cpp.o
 CMakeFiles/obj.clang-tblgen.dir/ClangOptionDocEmitter.cpp.o CMakeFiles/obj
 .clang-tblgen.dir/ClangSACheckersEmitter.cpp.o CMakeFiles/obj.clang-
 tblgen.dir/NeonEmitter.cpp.o CMakeFiles/obj.clang-
 tblgen.dir/TableGen.cpp.o  -o ../../../../bin/clang-tblgen
 -Wl,-rpath,/opt/local/lib ../../../../lib/libLLVMSupport.a
 ../../../../lib/libLLVMTableGen.a ../../../../lib/libLLVMSupport.a -lm
 ../../../../lib/libLLVMDemangle.a
 dyld: lazy symbol binding failed: Symbol not found: _lto_module_is_thinlto
   Referenced from: /opt/local/libexec/llvm-3.7/bin/ld
   Expected in: /opt/local/libexec/llvm-3.7/bin/../lib/libLTO.dylib

 dyld: Symbol not found: _lto_module_is_thinlto
   Referenced from: /opt/local/libexec/llvm-3.7/bin/ld
   Expected in: /opt/local/libexec/llvm-3.7/bin/../lib/libLTO.dylib
 }}}

 `ld64-latest` has been built with `thinlto` support, it appears, but this
 support is not found in  the `libLTO.dylib` that is being referenced.

 examining `ld64-latest`, I note that the previous version used a fixed
 reference to the `libLTO.dylib` that it was built against:

 {{{
 $ sudo port activate ld64-latest
 The following versions of ld64-latest are currently installed:
  1) ld64-latest @274.2_2+llvm39+universal
  2) ld64-latest @274.2_2+llvm80+universal (active)
 Enter a number to select an option: 1
 --->  Deactivating ld64-latest @274.2_2+llvm80+universal
 --->  Cleaning ld64-latest
 --->  Activating ld64-latest @274.2_2+llvm39+universal

 $ otool -L /opt/local/bin/ld-latest
 /opt/local/bin/ld-latest:
         /opt/local/libexec/llvm-3.9/lib/libLTO.dylib (compatibility
 version 1.0.0, current version 3.9.1)
         /usr/lib/libc++abi.dylib (compatibility version 1.0.0, current
 version 3.9.1)
         /opt/local/lib/libxar.1.dylib (compatibility version 1.0.0,
 current version 1.0.0)
         /usr/lib/libc++.1.dylib (compatibility version 1.0.0, current
 version 3.9.1)
         /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current
 version 125.2.11)
 }}}

 but the new version, built against `llvm80`, uses an `@rpath` reference to
 `libLTO.dylib`, and presumably that is getting confused in the build error
 above, and finding the old `libLTO.dylib` from `llvm-3.7` instead of the
 one `ld64-latest` was built against:
 {{{
 $ port -v installed | grep ld64
   ld64 @3_1+universal-ld64_127-ld64_236-ld64_97 (active) platform='darwin
 10' archs='i386 x86_64' date='2018-09-20T16:56:39-0700'
   ld64-236 @236.3_8+llvm39+universal-llvm34 (active) platform='darwin 10'
 archs='i386 x86_64' date='2018-01-11T17:34:16-0800'
   ld64-latest @274.2_2+llvm39+universal-llvm34 platform='darwin 10'
 archs='i386 x86_64' date='2017-11-26T13:19:27-0800'
   ld64-latest @274.2_2+llvm80+universal-llvm34 (active) platform='darwin
 10' archs='i386 x86_64' date='2019-12-29T15:03:58-0800'


 $ file /opt/local/bin/ld-latest
 /opt/local/bin/ld-latest: Mach-O universal binary with 2 architectures:
 [x86_64:Mach-O 64-bit x86_64 executable,
 flags:<NOUNDEFS|DYLDLINK|TWOLEVEL|BINDS_TO_WEAK|PIE>] [i386]

 $ otool -L /opt/local/bin/ld-latest
 /opt/local/bin/ld-latest:
         @rpath/libLTO.dylib (compatibility version 1.0.0, current version
 8.0.1)
         /usr/lib/libc++abi.dylib (compatibility version 1.0.0, current
 version 5.0.1)
         /opt/local/lib/libxar.1.dylib (compatibility version 1.0.0,
 current version 1.0.0)
         /usr/lib/libc++.1.dylib (compatibility version 1.0.0, current
 version 5.0.1)
         /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current
 version 125.2.11)
 }}}


 It looks like `ld64-latest` will need to be built against a fully-
 specified `libLTO.dylib` to function properly, and the `@rpath` reference
 to `libLTO.dylib` is unreliable.

-- 
Ticket URL: <https://trac.macports.org/ticket/59983>
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