我按照http://gbalats.github.io/2015/12/10/compiling-autotooled-projects-to-LLVM-bitcode.html#compiling-llvm-from-source-with-gold-plugin上的说明进行尝试将包括 coreutils 在内的各种项目编译到 LLVM IR。
我尝试使用 Clang 3.4 和一个简单的测试文件在 Ubuntu 14.04 上测试我的安装
clang -flto -fuse-ld=gold -Wl,-plugin-opt=also-emit-llvm test.o
如前所述,但失败了
test.o: file not recognized: File format not recognized
clang: error: linker command failed with exit code 1 (use -v to see invocation)
但是,添加参数后,-B/usr/lib/gold-ld
我可以编译测试文件。
尽管如此,编译 coreutils 仍然失败并出现以下错误:
/usr/lib/gold-ld/ld: error: src/libver.a: no archive symbol table (run ranlib)
/usr/lib/gold-ld/ld: error: lib/libcoreutils.a: no archive symbol table (run ranlib)
/usr/lib/gold-ld/ld: error: lib/libcoreutils.a: no archive symbol table (run ranlib)
/tmp/lto-llvm-dc31af.o:ld-temp.o:function usage: error: undefined reference to 'program_name'
/tmp/lto-llvm-dc31af.o:ld-temp.o:function usage: error: undefined reference to 'quote'
/tmp/lto-llvm-dc31af.o:ld-temp.o:function usage: error: undefined reference to 'program_name'
/tmp/lto-llvm-dc31af.o:ld-temp.o:function main: error: undefined reference to 'set_program_name'
/tmp/lto-llvm-dc31af.o:ld-temp.o:function main: error: undefined reference to 'exit_failure'
/tmp/lto-llvm-dc31af.o:ld-temp.o:function main: error: undefined reference to 'close_stdout'
/tmp/lto-llvm-dc31af.o:ld-temp.o:function main: error: undefined reference to 'parse_user_spec'
/tmp/lto-llvm-dc31af.o:ld-temp.o:function main: error: undefined reference to 'xgetgroups'
/tmp/lto-llvm-dc31af.o:ld-temp.o:function main: error: undefined reference to 'quote'
/tmp/lto-llvm-dc31af.o:ld-temp.o:function main: error: undefined reference to 'parse_user_spec'
/tmp/lto-llvm-dc31af.o:ld-temp.o:function main: error: undefined reference to 'xgetgroups'
/tmp/lto-llvm-dc31af.o:ld-temp.o:function main: error: undefined reference to 'quote'
/tmp/lto-llvm-dc31af.o:ld-temp.o:function main: error: undefined reference to 'Version'
/tmp/lto-llvm-dc31af.o:ld-temp.o:function main: error: undefined reference to 'version_etc'
/tmp/lto-llvm-dc31af.o:ld-temp.o:function main: error: undefined reference to 'quote'
/tmp/lto-llvm-dc31af.o:ld-temp.o:function parse_additional_groups: error: undefined reference to 'xstrdup'
/tmp/lto-llvm-dc31af.o:ld-temp.o:function parse_additional_groups: error: undefined reference to 'xstrtoul'
/tmp/lto-llvm-dc31af.o:ld-temp.o:function parse_additional_groups: error: undefined reference to 'x2nrealloc'
最后执行的命令是:
clang -flto -B/usr/lib/gold-ld -Wl,--as-needed -flto -B/usr/lib/gold-ld -fuse-ld=gold -Wl,-plugin-opt=also-emit-llvm -o src/chroot src/chroot.o src/libver.a lib/libcoreutils.a lib/libcoreutils.a
在 libver.a 和 libcoreutils.a 上手动执行 llvm-ranlib 不会改变结果。执行llvm-nm -s src/libver.a
打印以下内容:
D Version
但是,通过正常构建,输出如下:
Archive map
Version in version.o
version.o:
00000000 D Version
llvm-ranlib 有问题吗?您对如何修复链接器错误有任何建议吗?