[DFSAN][MIPS] adding support of DFSAN for MIPS64

[sdkie]

Summary

Minor changes to enable DFSAN on MIPS64

[sdkie]

corrected 'kAppAddr' value

[pcc]

lib/dfsan/dfsan.h

50

I think you will need to make a similar change to LLVM (search for ShadowPtrMask in lib/Transforms/Instrumentation/DataFlowSanitizer.cpp).

[pcc]

LGTM

[sdkie]

@pcc: I don't have commit access.
Can you commit both the patches for me?

Thanks.

[pcc]

Closed by commit rL223517 (authored by @pcc).

cmake/config-ix.cmake

function(filter_available_targets out_var)
   set(${out_var} ${archs} PARENT_SCOPE)
 endfunction()
 
 # Arhcitectures supported by compiler-rt libraries.
 filter_available_targets(SANITIZER_COMMON_SUPPORTED_ARCH
   x86_64 i386 i686 powerpc64 powerpc64le arm aarch64 mips mips64 mipsel mips64el)
 filter_available_targets(ASAN_SUPPORTED_ARCH
   x86_64 i386 i686 powerpc64 powerpc64le arm mips mipsel mips64 mips64el)
-filter_available_targets(DFSAN_SUPPORTED_ARCH x86_64)
+filter_available_targets(DFSAN_SUPPORTED_ARCH x86_64 mips64 mips64el)
 filter_available_targets(LSAN_SUPPORTED_ARCH x86_64)
 # LSan common files should be available on all architectures supported
 # by other sanitizers (even if they build into dummy object files).
 filter_available_targets(LSAN_COMMON_SUPPORTED_ARCH
   ${SANITIZER_COMMON_SUPPORTED_ARCH})
 filter_available_targets(MSAN_SUPPORTED_ARCH x86_64 mips64 mips64el)
 filter_available_targets(PROFILE_SUPPORTED_ARCH x86_64 i386 i686 arm mips mips64
   mipsel mips64el aarch64 powerpc64 powerpc64le)

lib/dfsan/CMakeLists.txt

 include_directories(..)
 
 # Runtime library sources and build flags.
 set(DFSAN_RTL_SOURCES
   dfsan.cc
   dfsan_custom.cc
   dfsan_interceptors.cc)
 set(DFSAN_COMMON_CFLAGS ${SANITIZER_COMMON_CFLAGS})
 # Prevent clang from generating libc calls.
 append_list_if(COMPILER_RT_HAS_FFREESTANDING_FLAG -ffreestanding DFSAN_COMMON_CFLAGS)
 
 # Static runtime library.
 add_custom_target(dfsan)
-set(arch "x86_64")
-if(CAN_TARGET_${arch})
+foreach(arch ${DFSAN_SUPPORTED_ARCH})
   set(DFSAN_CFLAGS ${DFSAN_COMMON_CFLAGS})
   append_list_if(COMPILER_RT_HAS_FPIE_FLAG -fPIE DFSAN_CFLAGS)
   add_compiler_rt_runtime(clang_rt.dfsan-${arch} ${arch} STATIC
     SOURCES ${DFSAN_RTL_SOURCES}
             $<TARGET_OBJECTS:RTInterception.${arch}>
             $<TARGET_OBJECTS:RTSanitizerCommon.${arch}>
             $<TARGET_OBJECTS:RTSanitizerCommonLibc.${arch}>
     CFLAGS ${DFSAN_CFLAGS})
   set(DFSAN_NOLIBC_CFLAGS ${DFSAN_COMMON_CFLAGS} -DDFSAN_NOLIBC)
   add_compiler_rt_runtime(clang_rt.dfsan-libc-${arch} ${arch} STATIC
     SOURCES ${DFSAN_RTL_SOURCES}
             $<TARGET_OBJECTS:RTSanitizerCommon.${arch}>
             CFLAGS ${DFSAN_NOLIBC_CFLAGS})
   add_sanitizer_rt_symbols(clang_rt.dfsan-${arch} dfsan.syms.extra)
   add_dependencies(dfsan
     clang_rt.dfsan-${arch}
     clang_rt.dfsan-${arch}-symbols)
-endif()
+endforeach()
 
 set(dfsan_abilist_filename ${COMPILER_RT_OUTPUT_DIR}/dfsan_abilist.txt)
 add_custom_target(dfsan_abilist ALL
   DEPENDS ${dfsan_abilist_filename})
 add_custom_command(OUTPUT ${dfsan_abilist_filename}
                    VERBATIM
                    COMMAND
                      cat ${CMAKE_CURRENT_SOURCE_DIR}/done_abilist.txt
                          ${CMAKE_CURRENT_SOURCE_DIR}/libc_ubuntu1404_abilist.txt
                          > ${dfsan_abilist_filename}
                    DEPENDS done_abilist.txt libc_ubuntu1404_abilist.txt)
 add_dependencies(dfsan dfsan_abilist)
 install(FILES ${dfsan_abilist_filename}
         DESTINATION ${COMPILER_RT_INSTALL_PATH})
 
 add_dependencies(compiler-rt dfsan)

lib/dfsan/dfsan.h

void dfsan_set_label(dfsan_label label, T &data) {  // NOLINT
   dfsan_set_label(label, (void *)&data, sizeof(T));
 }
 
 namespace __dfsan {
 
 void InitializeInterceptors();
 
 inline dfsan_label *shadow_for(void *ptr) {
+#if defined(__x86_64__)
   return (dfsan_label *) ((((uptr) ptr) & ~0x700000000000) << 1);
+#elif defined(__mips64)
+  return (dfsan_label *) ((((uptr) ptr) & ~0xF000000000) << 1);
+#endif
 }
 
 inline const dfsan_label *shadow_for(const void *ptr) {
   return shadow_for(const_cast<void *>(ptr));
 }
 
 struct Flags {
   // Whether to warn on unimplemented functions.

lib/dfsan/dfsan.cc

 // +--------------------+ 0x000000000000
 //
 // To derive a shadow memory address from an application memory address,
 // bits 44-46 are cleared to bring the address into the range
 // [0x000000008000,0x100000000000).  Then the address is shifted left by 1 to
 // account for the double byte representation of shadow labels and move the
 // address into the shadow memory range.  See the function shadow_for below.
 
+// On Linux/MIPS64, memory is laid out as follows:
+//
+// +--------------------+ 0x10000000000 (top of memory)
+// | application memory |
+// +--------------------+ 0xF000008000 (kAppAddr)
+// |                    |
+// |       unused       |
+// |                    |
+// +--------------------+ 0x2200000000 (kUnusedAddr)
+// |    union table     |
+// +--------------------+ 0x2000000000 (kUnionTableAddr)
+// |   shadow memory    |
+// +--------------------+ 0x0000010000 (kShadowAddr)
+// | reserved by kernel |
+// +--------------------+ 0x0000000000
+
 typedef atomic_dfsan_label dfsan_union_table_t[kNumLabels][kNumLabels];
 
+#if defined(__x86_64__)
 static const uptr kShadowAddr = 0x10000;
 static const uptr kUnionTableAddr = 0x200000000000;
 static const uptr kUnusedAddr = kUnionTableAddr + sizeof(dfsan_union_table_t);
 static const uptr kAppAddr = 0x700000008000;
+#elif defined(__mips64)
+static const uptr kShadowAddr = 0x10000;
+static const uptr kUnionTableAddr = 0x2000000000;
+static const uptr kUnusedAddr = kUnionTableAddr + sizeof(dfsan_union_table_t);
+static const uptr kAppAddr = 0x7000008000;
+#else
+# error "DFSan not supported for this platform!"
+#endif
 
 static atomic_dfsan_label *union_table(dfsan_label l1, dfsan_label l2) {
   return &(*(dfsan_union_table_t *) kUnionTableAddr)[l1][l2];
 }
 
 // Checks we do not run out of labels.
 static void dfsan_check_label(dfsan_label label) {
   if (label == kInitializingLabel) {