[SCUDO] add cmake options for custom sysroot

[michaelrj]

Summary

These options will allow the SCUDO standalone to be built with custom
headers. Specifically, this patch will enable building with the
LLVM-libc headers.

[abrachet]

LGTM

[michaelrj]

add flag for easier building of scudo with the LLVM libc headers

[abrachet]

compiler-rt/lib/scudo/standalone/CMakeLists.txt

145

I think you can do include_directories(SYSTEM ${COMPILER_RT_BINARY_DIR}/../libc/include/) and then you won't need "-I ${COMPILER_RT_BINARY_DIR}/../libc/include/". But not sure

[michaelrj]

remove redundant cflag

compiler-rt/lib/scudo/standalone/CMakeLists.txt

145

ah, you're right. Fixed

compiler-rt/CMakeLists.txt

 option(COMPILER_RT_BUILD_XRAY_NO_PREINIT "Build xray with no preinit patching" OFF)
 mark_as_advanced(COMPILER_RT_BUILD_XRAY_NO_PREINIT)
 option(COMPILER_RT_BUILD_ORC "Build ORC runtime" ON)
 mark_as_advanced(COMPILER_RT_BUILD_ORC)
 option(COMPILER_RT_BUILD_GWP_ASAN "Build GWP-ASan, and link it into SCUDO" ON)
 mark_as_advanced(COMPILER_RT_BUILD_GWP_ASAN)
 option(COMPILER_RT_ENABLE_CET "Build Compiler RT with CET enabled" OFF)
 
+option(COMPILER_RT_SCUDO_STANDALONE_SYSROOT_PATH "Set custom sysroot for building SCUDO standalone" OFF)
+mark_as_advanced(COMPILER_RT_SCUDO_STANDALONE_SYSROOT_PATH)
+option(COMPILER_RT_SCUDO_STANDALONE_BUILD_SHARED "Build SCUDO standalone for shared libraries" ON)
+mark_as_advanced(COMPILER_RT_SCUDO_STANDALONE_BUILD_SHARED)
+option(COMPILER_RT_BUILD_SCUDO_STANDALONE_WITH_LLVM_LIBC "Build SCUDO standalone with LLVM's libc headers" OFF)
+mark_as_advanced(COMPILER_RT_BUILD_SCUDO_STANDALONE_WITH_LLVM_LIBC)
+
 if(FUCHSIA)
   set(COMPILER_RT_HWASAN_WITH_INTERCEPTORS_DEFAULT OFF)
 else()
   set(COMPILER_RT_HWASAN_WITH_INTERCEPTORS_DEFAULT ON)
 endif()
 set(COMPILER_RT_HWASAN_WITH_INTERCEPTORS ${COMPILER_RT_HWASAN_WITH_INTERCEPTORS_DEFAULT} CACHE BOOL "Enable libc interceptors in HWASan (testing mode)")
 
 set(COMPILER_RT_BAREMETAL_BUILD OFF CACHE BOOL

compiler-rt/lib/scudo/standalone/CMakeLists.txt

 list(APPEND SCUDO_LINK_FLAGS -Wl,-z,defs,-z,now,-z,relro)
 
 list(APPEND SCUDO_LINK_FLAGS -ffunction-sections -fdata-sections -Wl,--gc-sections)
 
 # We don't use the C++ standard library, so avoid including it by mistake.
 append_list_if(COMPILER_RT_HAS_NOSTDLIBXX_FLAG -nostdlib++ SCUDO_LINK_FLAGS)
 append_list_if(CXX_SUPPORTS_UNWINDLIB_NONE_FLAG --unwindlib=none SCUDO_LINK_FLAGS)
 
+if(COMPILER_RT_SCUDO_STANDALONE_SYSROOT_PATH)
+  list(APPEND SCUDO_CFLAGS "--sysroot=${COMPILER_RT_SCUDO_STANDALONE_SYSROOT_PATH}")
+endif()
+
 if(ANDROID)
   list(APPEND SCUDO_CFLAGS -fno-emulated-tls)
 
 # Put the shared library in the global group. For more details, see
 # android-changes-for-ndk-developers.md#changes-to-library-search-order
   append_list_if(COMPILER_RT_HAS_Z_GLOBAL -Wl,-z,global SCUDO_LINK_FLAGS)
 endif()
 
append_list_if(COMPILER_RT_HAS_OMIT_FRAME_POINTER_FLAG -fno-omit-frame-pointer
                                                          -mno-omit-leaf-frame-pointer
                  SCUDO_CFLAGS)
   list(APPEND SCUDO_CFLAGS -DGWP_ASAN_HOOKS)
 
 endif()
 
 set(SCUDO_LINK_LIBS ${COMPILER_RT_UNWINDER_LINK_LIBS})
 
+if(COMPILER_RT_BUILD_SCUDO_STANDALONE_WITH_LLVM_LIBC)
+  include_directories(${COMPILER_RT_BINARY_DIR}/../libc/include/)
+
+  set(SCUDO_DEPS libc-headers)
+
+  list(APPEND SCUDO_CFLAGS "-ffreestanding")
+endif()
+
 append_list_if(COMPILER_RT_HAS_LIBPTHREAD -pthread SCUDO_LINK_FLAGS)
 
 append_list_if(FUCHSIA zircon SCUDO_LINK_LIBS)
 
 if(COMPILER_RT_DEFAULT_TARGET_ARCH MATCHES "mips|mips64|mipsel|mips64el")
   list(APPEND SCUDO_LINK_LIBS atomic)
 endif()
 
 if(COMPILER_RT_HAS_SCUDO_STANDALONE)
   add_compiler_rt_object_libraries(RTScudoStandalone
     ARCHS ${SCUDO_STANDALONE_SUPPORTED_ARCH}
     SOURCES ${SCUDO_SOURCES}
     ADDITIONAL_HEADERS ${SCUDO_HEADERS}
-    CFLAGS ${SCUDO_CFLAGS})
+    CFLAGS ${SCUDO_CFLAGS}
+    DEPS ${SCUDO_DEPS})
   add_compiler_rt_object_libraries(RTScudoStandaloneCWrappers
     ARCHS ${SCUDO_STANDALONE_SUPPORTED_ARCH}
     SOURCES ${SCUDO_SOURCES_C_WRAPPERS}
     ADDITIONAL_HEADERS ${SCUDO_HEADERS}
-    CFLAGS ${SCUDO_CFLAGS})
+    CFLAGS ${SCUDO_CFLAGS}
+    DEPS ${SCUDO_DEPS})
   add_compiler_rt_object_libraries(RTScudoStandaloneCxxWrappers
     ARCHS ${SCUDO_STANDALONE_SUPPORTED_ARCH}
     SOURCES ${SCUDO_SOURCES_CXX_WRAPPERS}
     ADDITIONAL_HEADERS ${SCUDO_HEADERS}
-    CFLAGS ${SCUDO_CFLAGS})
+    CFLAGS ${SCUDO_CFLAGS}
+    DEPS ${SCUDO_DEPS})
 
   add_compiler_rt_runtime(clang_rt.scudo_standalone
     STATIC
     ARCHS ${SCUDO_STANDALONE_SUPPORTED_ARCH}
     SOURCES ${SCUDO_SOURCES} ${SCUDO_SOURCES_C_WRAPPERS}
     ADDITIONAL_HEADERS ${SCUDO_HEADERS}
     CFLAGS ${SCUDO_CFLAGS}
+    DEPS ${SCUDO_DEPS}
     OBJECT_LIBS ${SCUDO_OBJECT_LIBS}
     PARENT_TARGET scudo_standalone)
   add_compiler_rt_runtime(clang_rt.scudo_standalone_cxx
     STATIC
     ARCHS ${SCUDO_STANDALONE_SUPPORTED_ARCH}
     SOURCES ${SCUDO_SOURCES_CXX_WRAPPERS}
     ADDITIONAL_HEADERS ${SCUDO_HEADERS}
     CFLAGS ${SCUDO_CFLAGS}
+    DEPS ${SCUDO_DEPS}
     PARENT_TARGET scudo_standalone)
 
+  if(COMPILER_RT_SCUDO_STANDALONE_BUILD_SHARED)
     add_compiler_rt_runtime(clang_rt.scudo_standalone
       SHARED
       ARCHS ${SCUDO_STANDALONE_SUPPORTED_ARCH}
       SOURCES ${SCUDO_SOURCES} ${SCUDO_SOURCES_C_WRAPPERS} ${SCUDO_SOURCES_CXX_WRAPPERS}
       ADDITIONAL_HEADERS ${SCUDO_HEADERS}
       CFLAGS ${SCUDO_CFLAGS}
+      DEPS ${SCUDO_DEPS}
       OBJECT_LIBS ${SCUDO_OBJECT_LIBS}
       LINK_FLAGS ${SCUDO_LINK_FLAGS}
       LINK_LIBS ${SCUDO_LINK_LIBS}
       PARENT_TARGET scudo_standalone)
+  endif()
 
   add_subdirectory(benchmarks)
   if(COMPILER_RT_INCLUDE_TESTS)
     add_subdirectory(tests)
   endif()
 endif()