Question

我有一个脚本，可以从源代码构建llvm / clang 3.42 （使用configure + make）。 在ubuntu 14.04.5 LTS 上顺利运行。当我升级到 ubuntu 17.04 时，构建失败。

以下是构建脚本：

svn co https://llvm.org/svn/llvm-project/llvm/tags/RELEASE_342/final llvm
svn co https://llvm.org/svn/llvm-project/cfe/tags/RELEASE_342/final llvm/tools/clang
svn co https://llvm.org/svn/llvm-project/compiler-rt/tags/RELEASE_342/final llvm/projects/compiler-rt
svn co https://llvm.org/svn/llvm-project/libcxx/tags/RELEASE_342/final llvm/projects/libcxx

rm -rf llvm/.svn
rm -rf llvm/tools/clang/.svn
rm -rf llvm/projects/compiler-rt/.svn
rm -rf llvm/projects/libcxx/.svn

cd llvm
./configure \
--enable-optimized \
--disable-assertions \
--enable-targets=host \
--with-python="/usr/bin/python2"

make -j `nproc`

以下是我得到的错误（TLDR： malloc 的定义问题， calloc ， realloc 和免费）

/usr/include/malloc.h:38:14: error: declaration conflicts with target of using declaration already in scope
extern void *malloc (size_t __size) __THROW __attribute_malloc__ __wur;
             ^
/usr/include/stdlib.h:427:14: note: target of using declaration
extern void *malloc (size_t __size) __THROW __attribute_malloc__ __wur;
             ^
/usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3./stdlib.h:65:12: note: using declaration
using std::malloc;
           ^
In file included from /home/oren/GIT/LatestKlee/llvm/projects/compiler-rt/lib/tsan/rtl/tsan_platform_linux.cc:47:
/usr/include/malloc.h:41:14: error: declaration conflicts with target of using declaration already in
  scope
extern void *calloc (size_t __nmemb, size_t __size)
             ^
/usr/include/stdlib.h:429:14: note: target of using declaration
extern void *calloc (size_t __nmemb, size_t __size)
             ^
/usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0/stdlib.h:59:12: note: using declaration
using std::calloc;
           ^
In file included from /home/oren/GIT/LatestKlee/llvm/projects/compiler-rt/lib/tsan/rtl/tsan_platform_linux.cc:47:
/usr/include/malloc.h:49:14: error: declaration conflicts with target of using declaration already in
  scope
extern void *realloc (void *__ptr, size_t __size)
             ^
/usr/include/stdlib.h:441:14: note: target of using declaration
extern void *realloc (void *__ptr, size_t __size)
             ^
/usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0/stdlib.h:73:12: note: using declaration
using std::realloc;
           ^
In file included from /home/oren/GIT/LatestKlee/llvm/projects/compiler-rt/lib/tsan/rtl/tsan_platform_linux.cc:47:
/usr/include/malloc.h:53:13: error: declaration conflicts with target of using declaration already in
  scope
extern void free (void *__ptr) __THROW;
            ^
/usr/include/stdlib.h:444:13: note: target of using declaration
extern void free (void *__ptr) __THROW;
            ^
/usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0/stdlib.h:61:12: note: using declaration
using std::free;
           ^
COMPILE:   clang_linux/tsan-x86_64/x86_64: /home/oren/GIT/LatestKlee/llvm/projects/compiler-rt/lib/tsan/rtl/tsan_rtl_mutex.cc
4 errors generated.
Makefile:267: recipe for target '/home/oren/GIT/LatestKlee/llvm/tools/clang/runtime/compiler-rt/clang_linux/tsan-x86_64/x86_64/SubDir.lib__tsan__rtl/tsan_platform_linux.o' failed
make[5]: *** [/home/oren/GIT/LatestKlee/llvm/tools/clang/runtime/compiler-rt/clang_linux/tsan-x86_64/x86_64/SubDir.lib__tsan__rtl/tsan_platform_linux.o] Error 1

ubuntu 17.04附带的默认gcc版本是6.3。也许这是gcc 6.3使用的默认C ++方言的问题？非常感谢任何帮助，谢谢！

Answer 1

这似乎是LLVM 3.4.2 tsan（Thread Sanitizer）无法使用GCC 6.x构建的问题，如先前在此处报道的那样：

https://aur.archlinux.org/packages/clang34-analyzer-split

似乎包含stdlib.h和malloc.h是冲突的，因为它们都定义了malloc和朋友。

这个问题可能仅出现在tsan中，所以如果tsan对你的LLVM构建没有帮助（很可能），并且你希望坚持使用系统用于构建LLVM的gcc，您可以考虑完全禁用tsan。

如果您正在运行CMake构建（如here中所述），则可以通过评论llvm/projects/compiler-rt/lib/CMakeLists.txt的第29行来执行此操作：

if (CMAKE_SYSTEM_NAME MATCHES "Linux" AND NOT ANDROID)  
  add_subdirectory(tsan) # comment out this line

如果您被迫坚持使用configure版本，我最好的猜测是删除tsan-x86_64第63行中的llvm/projects/compiler-rt/make/clang_linux.mk目标：

Configs += full-x86_64 profile-x86_64 san-x86_64 asan-x86_64 --> tsan-x86_64 <--

Answer 2

我在Ubuntu 16.10上面临同样的问题。它有默认的gcc 6.2。您需要指示LLVM构建系统使用gcc 4.9。另外，我建议你完全删除GCC6。

$ sudo apt-get remove g++-6 gcc-6 cpp
$ sudo apt-get install gcc-4.9 g++4.9
$ export CC=/usr/bin/gcc-4.9
$ export CXX=/usr/bin/g++-4.9
$ export CPP=/usr/bin/cpp-4.9
$ ./configure
$ make

也许你需要：

$ sudo ln -s /usr/bin/cpp-4.9 /usr/bin/cpp

来自源代码的llvm 3.42构建在ubuntu 17.04上失败

2 个答案: