[scudo] Add a minimal runtime for -fsanitize-minimal-runtime compatibility

[cryptoad]

Summary

This patch follows D48373.

The point is to be able to use Scudo with -fsanitize-minimal-runtime. For that
we need a runtime that doesn't embed the UBSan one. This results in binaries
that can be compiled with -fsanitize=scudo,integer -fsanitize-minimal-runtime.

lib/scudo/CMakeLists.txt

 add_compiler_rt_component(scudo)
 
 include_directories(..)
 
 set(SCUDO_CFLAGS ${SANITIZER_COMMON_CFLAGS})
 # SANITIZER_COMMON_CFLAGS include -fno-builtin, but we actually want builtins!
 list(APPEND SCUDO_CFLAGS -fbuiltin)
 append_rtti_flag(OFF SCUDO_CFLAGS)
 
-set(SCUDO_DYNAMIC_LIBS ${SANITIZER_COMMON_LINK_LIBS})
-append_list_if(COMPILER_RT_HAS_LIBDL dl SCUDO_DYNAMIC_LIBS)
-append_list_if(COMPILER_RT_HAS_LIBRT rt SCUDO_DYNAMIC_LIBS)
-append_list_if(COMPILER_RT_HAS_LIBPTHREAD pthread SCUDO_DYNAMIC_LIBS)
-append_list_if(COMPILER_RT_HAS_LIBLOG log SCUDO_DYNAMIC_LIBS)
+set(SCUDO_MINIMAL_DYNAMIC_LIBS ${SANITIZER_COMMON_LINK_LIBS})
+append_list_if(COMPILER_RT_HAS_LIBDL dl SCUDO_MINIMAL_DYNAMIC_LIBS)
+append_list_if(COMPILER_RT_HAS_LIBRT rt SCUDO_MINIMAL_DYNAMIC_LIBS)
+append_list_if(COMPILER_RT_HAS_LIBPTHREAD pthread SCUDO_MINIMAL_DYNAMIC_LIBS)
+append_list_if(COMPILER_RT_HAS_LIBLOG log SCUDO_MINIMAL_DYNAMIC_LIBS)
 
 set(SCUDO_DYNAMIC_LINK_FLAGS ${SANITIZER_COMMON_LINK_FLAGS})
 # Use gc-sections by default to avoid unused code being pulled in.
 list(APPEND SCUDO_DYNAMIC_LINK_FLAGS -Wl,--gc-sections)
 
-set(SCUDO_OBJECT_LIBS
+# The minimal Scudo runtime does not inlude the UBSan runtime.
+set(SCUDO_MINIMAL_OBJECT_LIBS
   RTSanitizerCommonNoTermination
   RTSanitizerCommonLibc
   RTInterception)
+set(SCUDO_OBJECT_LIBS ${SCUDO_MINIMAL_OBJECT_LIBS})
+set(SCUDO_DYNAMIC_LIBS ${SCUDO_MINIMAL_DYNAMIC_LIBS})
 
 if (FUCHSIA)
   list(APPEND SCUDO_CFLAGS -nostdinc++)
   list(APPEND SCUDO_DYNAMIC_LINK_FLAGS -nostdlib++)
 else()
+  list(APPEND SCUDO_DYNAMIC_LIBS ${SANITIZER_CXX_ABI_LIBRARY})
   list(APPEND SCUDO_OBJECT_LIBS
     RTSanitizerCommonCoverage
     RTSanitizerCommonSymbolizer
     RTUbsan)
-  list(APPEND SCUDO_DYNAMIC_LIBS ${SANITIZER_CXX_ABI_LIBRARY})
 endif()
 
 set(SCUDO_SOURCES
   scudo_allocator.cpp
   scudo_crc32.cpp
   scudo_errors.cpp
   scudo_flags.cpp
   scudo_malloc.cpp

 
 # Enable the AArch64 CRC32 feature for scudo_crc32.cpp, if available.
 # Note that it is enabled by default starting with armv8.1-a.
 if (COMPILER_RT_HAS_MCRC_FLAG)
   set_source_files_properties(scudo_crc32.cpp PROPERTIES COMPILE_FLAGS -mcrc)
 endif()
 
 if(COMPILER_RT_HAS_SCUDO)
+  add_compiler_rt_runtime(clang_rt.scudo_minimal
+    STATIC
+    ARCHS ${SCUDO_SUPPORTED_ARCH}
+    SOURCES ${SCUDO_SOURCES}
+    OBJECT_LIBS ${SCUDO_MINIMAL_OBJECT_LIBS}
+    CFLAGS ${SCUDO_CFLAGS}
+    PARENT_TARGET scudo)
+  add_compiler_rt_runtime(clang_rt.scudo_cxx_minimal
+    STATIC
+    ARCHS ${SCUDO_SUPPORTED_ARCH}
+    SOURCES ${SCUDO_CXX_SOURCES}
+    CFLAGS ${SCUDO_CFLAGS}
+    PARENT_TARGET scudo)
+
   add_compiler_rt_runtime(clang_rt.scudo
     STATIC
     ARCHS ${SCUDO_SUPPORTED_ARCH}
     SOURCES ${SCUDO_SOURCES}
     OBJECT_LIBS ${SCUDO_OBJECT_LIBS}
     CFLAGS ${SCUDO_CFLAGS}
     PARENT_TARGET scudo)
-
   add_compiler_rt_runtime(clang_rt.scudo_cxx
     STATIC
     ARCHS ${SCUDO_SUPPORTED_ARCH}
     SOURCES ${SCUDO_CXX_SOURCES}
     OBJECT_LIBS RTUbsan_cxx
     CFLAGS ${SCUDO_CFLAGS}
     PARENT_TARGET scudo)
 
+  add_compiler_rt_runtime(clang_rt.scudo_minimal
+    SHARED
+    ARCHS ${SCUDO_SUPPORTED_ARCH}
+    SOURCES ${SCUDO_SOURCES} ${SCUDO_CXX_SOURCES}
+    OBJECT_LIBS ${SCUDO_MINIMAL_OBJECT_LIBS}
+    CFLAGS ${SCUDO_CFLAGS}
+    LINK_FLAGS ${SCUDO_DYNAMIC_LINK_FLAGS}
+    LINK_LIBS ${SCUDO_MINIMAL_DYNAMIC_LIBS}
+    PARENT_TARGET scudo)
+
   add_compiler_rt_runtime(clang_rt.scudo
     SHARED
     ARCHS ${SCUDO_SUPPORTED_ARCH}
     SOURCES ${SCUDO_SOURCES} ${SCUDO_CXX_SOURCES}
     OBJECT_LIBS ${SCUDO_OBJECT_LIBS}
     CFLAGS ${SCUDO_CFLAGS}
     LINK_FLAGS ${SCUDO_DYNAMIC_LINK_FLAGS}
     LINK_LIBS ${SCUDO_DYNAMIC_LIBS}
     PARENT_TARGET scudo)
 endif()