[compiler-rt] Fix OS X build failure with Command Line Tools and without full Xcode installation

[kubamracek]

Summary

On OS X, if you don't have a full Xcode installation, but just the Command Line Tools package, xcrun and xcodebuild don't return a valid SDK root path. In these cases, let's use "/" as the SDK root (which is where the headers and libraries are installed).

See http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20150202/256851.html.

[kubamracek]

Updating the patch to omit the -isysroot completely instead of using "/".

[kubamracek]

So is this okay to commit?

[kubamracek]

Landed in r230847.

CMakeLists.txt

if(APPLE)
   set(SANITIZER_COMMON_SUPPORTED_DARWIN_OS osx)
   if (IOSSIM_SDK_DIR AND NOT MACOSX_VERSION_MIN_FLAG)
     list(APPEND SANITIZER_COMMON_SUPPORTED_DARWIN_OS iossim)
   endif()
 
   set(SANITIZER_MIN_OSX_VERSION 10.7)
   set(CMAKE_OSX_DEPLOYMENT_TARGET "") # We're setting the flag manually below.
   set(DARWIN_osx_CFLAGS -mmacosx-version-min=${SANITIZER_MIN_OSX_VERSION}
-    -isysroot ${OSX_SDK_DIR} -stdlib=libc++)
+    -stdlib=libc++)
   set(DARWIN_iossim_CFLAGS
     -mios-simulator-version-min=7.0 -isysroot ${IOSSIM_SDK_DIR})
   set(DARWIN_osx_LINKFLAGS -mmacosx-version-min=${SANITIZER_MIN_OSX_VERSION}
-    -isysroot ${OSX_SDK_DIR} -stdlib=libc++)
+     -stdlib=libc++)
   set(DARWIN_iossim_LINKFLAGS
     -Wl,-ios_simulator_version_min,7.0.0
     -mios-simulator-version-min=7.0
     -isysroot ${IOSSIM_SDK_DIR})
+
+  if(OSX_SDK_DIR)
+    list(APPEND DARWIN_osx_CFLAGS -isysroot ${OSX_SDK_DIR})
+    list(APPEND DARWIN_osx_LINKFLAGS -isysroot ${OSX_SDK_DIR})
+  endif()
 endif()
 
 add_subdirectory(include)
 
 set(COMPILER_RT_LIBCXX_PATH ${LLVM_MAIN_SRC_DIR}/projects/libcxx)
 if(EXISTS ${COMPILER_RT_LIBCXX_PATH}/)
   set(COMPILER_RT_HAS_LIBCXX_SOURCES TRUE)
 else()

make/platform/clang_darwin.mk

 IOSSIM_DEPLOYMENT_ARGS += -isysroot $(IOSSIM_SDK)
 
 CFLAGS.eprintf    := $(CFLAGS) $(OSX_DEPLOYMENT_ARGS)
 CFLAGS.10.4   := $(CFLAGS) $(OSX_DEPLOYMENT_ARGS)
 
 CFLAGS.asan_osx_dynamic := \
   $(CFLAGS) -mmacosx-version-min=10.7 \
   -stdlib=libc++ \
-  -isysroot $(OSX_SDK) \
   -fno-builtin \
   -gline-tables-only \
   -DMAC_INTERPOSE_FUNCTIONS=1 \
   -DASAN_DYNAMIC=1
 
 CFLAGS.asan_iossim_dynamic := \
   $(CFLAGS) -mios-simulator-version-min=7.0 \
         -isysroot $(IOSSIM_SDK) \
         -fno-builtin \
   -gline-tables-only \
   -DMAC_INTERPOSE_FUNCTIONS=1 \
   -DASAN_DYNAMIC=1
 
 CFLAGS.ubsan_osx := $(CFLAGS) -mmacosx-version-min=10.6 \
-  -isysroot $(OSX_SDK) \
   -fno-builtin
 
 CFLAGS.ios.i386   := $(CFLAGS) $(IOSSIM_DEPLOYMENT_ARGS)
 CFLAGS.ios.x86_64 := $(CFLAGS) $(IOSSIM_DEPLOYMENT_ARGS)
 CFLAGS.ios.armv7  := $(CFLAGS) $(IOS_DEPLOYMENT_ARGS)
 CFLAGS.ios.armv7k := $(CFLAGS) $(IOS_DEPLOYMENT_ARGS)
 CFLAGS.ios.armv7s := $(CFLAGS) $(IOS_DEPLOYMENT_ARGS)
 CFLAGS.ios.arm64  := $(CFLAGS) $(IOS6_DEPLOYMENT_ARGS)

 CFLAGS.profile_ios.armv7  := $(CFLAGS) $(IOS_DEPLOYMENT_ARGS)
 CFLAGS.profile_ios.armv7k := $(CFLAGS) $(IOS_DEPLOYMENT_ARGS)
 CFLAGS.profile_ios.armv7s := $(CFLAGS) $(IOS_DEPLOYMENT_ARGS)
 CFLAGS.profile_ios.arm64  := $(CFLAGS) $(IOS6_DEPLOYMENT_ARGS)
 
 # Configure the asan_osx_dynamic library to be built shared.
 SHARED_LIBRARY.asan_osx_dynamic := 1
 LDFLAGS.asan_osx_dynamic := -lc++ -undefined dynamic_lookup -install_name @rpath/libclang_rt.asan_osx_dynamic.dylib \
-  -mmacosx-version-min=10.7 \
-  -isysroot $(OSX_SDK)
+  -mmacosx-version-min=10.7
 
 # Configure the asan_iossim_dynamic library to be built shared.
 SHARED_LIBRARY.asan_iossim_dynamic := 1
 # configure+make uses Clang, so we're using isysroot instead of --sysroot
 # or -Wl,-syslibroot.
 LDFLAGS.asan_iossim_dynamic := -undefined dynamic_lookup -install_name @rpath/libclang_rt.asan_iossim_dynamic.dylib \
   -Wl,-ios_simulator_version_min,7.0.0 \
   -mios-simulator-version-min=7.0 -isysroot $(IOSSIM_SDK)
 
+ifneq ($(OSX_SDK),)
+CFLAGS.asan_osx_dynamic += -isysroot $(OSX_SDK)
+LDFLAGS.asan_osx_dynamic += -isysroot $(OSX_SDK)
+CFLAGS.ubsan_osx += -isysroot $(OSX_SDK)
+LDFLAGS.ubsan_osx += -isysroot $(OSX_SDK)
+endif
+
 FUNCTIONS.eprintf := eprintf
 FUNCTIONS.10.4 := eprintf floatundidf floatundisf floatundixf
 
 FUNCTIONS.ios     := divmodsi4 udivmodsi4 mulosi4 mulodi4 muloti4
 # On x86, the divmod functions reference divsi.
 FUNCTIONS.ios.i386    := $(FUNCTIONS.ios) \
                          divsi3 udivsi3
 FUNCTIONS.ios.x86_64  := $(FUNCTIONS.ios.i386)