Assortment of Rust-related build fixes

This commit is an assortment of build fixes for LLVM that we've applied
for rust-lang/rust. These are unlikely to ever go upstream, but if we
could upstream them somehow that'd definitely be great! In any case for
now some rationale for these patches are:

  * We build on ancient CentOS containers for i686/x86_64 Linux
    releases. The libc header files there are insanely old and despite
    using a recent gcc/clang release the libc headers cause issues. Some
    various pieces are commented out or altered to pieces of LLVM that
    aren't exercised or used much by LLVM.

  * Sometimes there's some miscellaneous MSVC things here and there, but
    nothing crticial.

For details of changes to specific files:

-----------------------------------------------------------------------

 * llvm/lib/ExecutionEngine/RuntimeDyld/RTDyldMemoryManager.cpp

Fix compile on dist-i686-linux builder

If this lines are present then we apparently get errors [1] when compiling in
the current [2] dist-i686-linux container. Attempts to upgrade both gcc and
binutils did not fix the error, so it appears that this may just be a bug in the
super old glibc we're using on the dist-i686-linux container.

We don't actually need this code anyway, so just work around these issues by
removing references to the `*64` functions. This'll get things compiling
locally and shouldn't be a regression in functionality.

[1]: https://travis-ci.org/rust-lang/rust/jobs/257578199
[2]: https://github.com/rust-lang/rust/tree/eba9d7f08ce5c90549ee52337aca0010ad566f0d/src/ci/docker/dist-i686-linux

-----------------------------------------------------------------------

 * llvm/cmake/modules/CheckAtomic.cmake

Disable checks for libatomic for now

For whatever reason this is failing the i686-freebsd builder in the Rust repo
as-of this red-hot moment. The build seems to work fine without it so let's just
remove it for now and pray there's a better fix later.

Although if you're reading this and know of a better fix, we'd love to remove
this!

-----------------------------------------------------------------------

 * lld/CMakeLists.txt

Compile with /MT on MSVC

Can't seem to figure out how to do this without this patch...

-----------------------------------------------------------------------

 * compiler-rt/lib/asan/asan_linux.c
 * compiler-rt/lib/sanitizer_common/sanitizer_linux_libcdep.cc
 * llvm/lib/Support/Unix/Program.inc

Fix compile on dist-x86_64-linux builder for LLVM/sanitizers

Apparently glibc is so old it doesn't have the _POSIX_ARG_MAX constant. This
shouldn't affect anything we use anyway though. Apply similar treatment
to various definitions of things compiler-rt.

https://travis-ci.org/rust-lang/rust/jobs/399333071

compiler-rt/lib/asan/asan_linux.cc

@@ -214,7 +214,7 @@ void AsanCheckIncompatibleRT() {
       // the functions in dynamic ASan runtime instead of the functions in
       // system libraries, causing crashes later in ASan initialization.
       MemoryMappingLayout proc_maps(/*cache_enabled*/true);
-      char filename[PATH_MAX];
+      char filename[4096];
       MemoryMappedSegment segment(filename, sizeof(filename));
       while (proc_maps.Next(&segment)) {
         if (IsDynamicRTName(segment.filename)) {

compiler-rt/lib/sanitizer_common/sanitizer_linux_libcdep.cc

@@ -698,12 +698,8 @@ u32 GetNumberOfCPUs() {
   }
   internal_close(fd);
   return n_cpus;
-#elif SANITIZER_SOLARIS
-  return sysconf(_SC_NPROCESSORS_ONLN);
 #else
-  cpu_set_t CPUs;
-  CHECK_EQ(sched_getaffinity(0, sizeof(cpu_set_t), &CPUs), 0);
-  return CPU_COUNT(&CPUs);
+  return sysconf(_SC_NPROCESSORS_ONLN);
 #endif
 }
 

compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_posix.cc

@@ -106,6 +106,7 @@ typedef struct user_fpregs elf_fpregset_t;
 #endif
 
 #if SANITIZER_LINUX && !SANITIZER_ANDROID
+#include <stdio.h>
 #include <glob.h>
 #include <obstack.h>
 #include <mqueue.h>
@@ -1010,9 +1011,9 @@ CHECK_SIZE_AND_OFFSET(cmsghdr, cmsg_type);
 #endif
 
 #if SANITIZER_LINUX && (__ANDROID_API__ >= 21 || __GLIBC_PREREQ (2, 14))
-CHECK_TYPE_SIZE(mmsghdr);
-CHECK_SIZE_AND_OFFSET(mmsghdr, msg_hdr);
-CHECK_SIZE_AND_OFFSET(mmsghdr, msg_len);
+// CHECK_TYPE_SIZE(mmsghdr);
+// CHECK_SIZE_AND_OFFSET(mmsghdr, msg_hdr);
+// CHECK_SIZE_AND_OFFSET(mmsghdr, msg_len);
 #endif
 
 COMPILER_CHECK(sizeof(__sanitizer_dirent) <= sizeof(dirent));

lld/CMakeLists.txt

@@ -210,6 +210,19 @@ if (NOT LLVM_INSTALL_TOOLCHAIN_ONLY)
     )
 endif()
 
+if (MSVC)
+  FOREACH(flag
+      CMAKE_C_FLAGS_RELEASE CMAKE_C_FLAGS_RELWITHDEBINFO
+      CMAKE_C_FLAGS_DEBUG CMAKE_C_FLAGS_DEBUG_INIT
+      CMAKE_CXX_FLAGS_RELEASE  CMAKE_CXX_FLAGS_RELWITHDEBINFO
+      CMAKE_CXX_FLAGS_DEBUG  CMAKE_CXX_FLAGS_DEBUG_INIT)
+      if (MSVC)
+          STRING(REPLACE "/MD"  "/MT" "${flag}" "${${flag}}")
+          SET("${flag}" "${${flag}}")
+      endif (MSVC)
+  ENDFOREACH()
+endif()
+
 add_subdirectory(Common)
 add_subdirectory(lib)
 add_subdirectory(tools/lld)

llvm/cmake/modules/CheckAtomic.cmake

@@ -62,19 +62,20 @@ else()
   check_working_cxx_atomics64(HAVE_CXX_ATOMICS64_WITHOUT_LIB)
 endif()
 
-# If not, check if the library exists, and atomics work with it.
-if(NOT HAVE_CXX_ATOMICS64_WITHOUT_LIB)
-  check_library_exists(atomic __atomic_load_8 "" HAVE_CXX_LIBATOMICS64)
-  if(HAVE_CXX_LIBATOMICS64)
-    list(APPEND CMAKE_REQUIRED_LIBRARIES "atomic")
-    check_working_cxx_atomics64(HAVE_CXX_ATOMICS64_WITH_LIB)
-    if (NOT HAVE_CXX_ATOMICS64_WITH_LIB)
-      message(FATAL_ERROR "Host compiler must support std::atomic!")
-    endif()
-  else()
-    message(FATAL_ERROR "Host compiler appears to require libatomic, but cannot find it.")
-  endif()
-endif()
+# RUST-SPECIFIC - commented out, see commit message
+# # If not, check if the library exists, and atomics work with it.
+# if(NOT HAVE_CXX_ATOMICS64_WITHOUT_LIB)
+#   check_library_exists(atomic __atomic_load_8 "" HAVE_CXX_LIBATOMICS64)
+#   if(HAVE_CXX_LIBATOMICS64)
+#     list(APPEND CMAKE_REQUIRED_LIBRARIES "atomic")
+#     check_working_cxx_atomics64(HAVE_CXX_ATOMICS64_WITH_LIB)
+#     if (NOT HAVE_CXX_ATOMICS64_WITH_LIB)
+#       message(FATAL_ERROR "Host compiler must support std::atomic!")
+#     endif()
+#   else()
+#     message(FATAL_ERROR "Host compiler appears to require libatomic, but cannot find it.")
+#   endif()
+# endif()
 
 ## TODO: This define is only used for the legacy atomic operations in
 ## llvm's Atomic.h, which should be replaced.  Other code simply

llvm/lib/ExecutionEngine/RuntimeDyld/RTDyldMemoryManager.cpp

@@ -243,9 +243,9 @@ RTDyldMemoryManager::getSymbolAddressInProcess(const std::string &Name) {
   if (Name == "stat") return (uint64_t)&stat;
   if (Name == "fstat") return (uint64_t)&fstat;
   if (Name == "lstat") return (uint64_t)&lstat;
-  if (Name == "stat64") return (uint64_t)&stat64;
-  if (Name == "fstat64") return (uint64_t)&fstat64;
-  if (Name == "lstat64") return (uint64_t)&lstat64;
+  // if (Name == "stat64") return (uint64_t)&stat64;
+  // if (Name == "fstat64") return (uint64_t)&fstat64;
+  // if (Name == "lstat64") return (uint64_t)&lstat64;
   if (Name == "atexit") return (uint64_t)&atexit;
   if (Name == "mknod") return (uint64_t)&mknod;
 

llvm/lib/Support/Unix/Program.inc

@@ -462,7 +462,7 @@ bool llvm::sys::commandLineFitsWithinSystemLimits(StringRef Program,
   static long ArgMax = sysconf(_SC_ARG_MAX);
   // POSIX requires that _POSIX_ARG_MAX is 4096, which is the lowest possible
   // value for ARG_MAX on a POSIX compliant system.
-  static long ArgMin = _POSIX_ARG_MAX;
+  static long ArgMin = 4096;
 
   // This the same baseline used by xargs.
   long EffectiveArgMax = 128 * 1024;