[asan] Interceptors for Fuchsia

[mcgrathr]

Summary

Fuchsia uses the "memintrinsics" interceptors, though not via any
generalized interception mechanism. It doesn't use any other interceptors.

[mcgrathr]

Split out from D35865.

lib/asan/asan_interceptors.h

 #ifndef ASAN_INTERCEPTORS_H
 #define ASAN_INTERCEPTORS_H
 
 #include "asan_internal.h"
 #include "asan_interceptors_memintrinsics.h"
 #include "interception/interception.h"
 #include "sanitizer_common/sanitizer_platform_interceptors.h"
 
+namespace __asan {
+
+void InitializeAsanInterceptors();
+void InitializePlatformInterceptors();
+
+#define ENSURE_ASAN_INITED() do { \
+  CHECK(!asan_init_is_running); \
+  if (UNLIKELY(!asan_inited)) { \
+    AsanInitFromRtl(); \
+  } \
+} while (0)
+
+}  // namespace __asan
+
+// There is no general interception at all on Fuchsia.
+// Only the functions in asan_interceptors_memintrinsics.h are
+// really defined to replace libc functions.
+#if !SANITIZER_FUCHSIA
+
 // Use macro to describe if specific function should be
 // intercepted on a given platform.
 #if !SANITIZER_WINDOWS
 # define ASAN_INTERCEPT_ATOLL_AND_STRTOLL 1
 # define ASAN_INTERCEPT__LONGJMP 1
 # define ASAN_INTERCEPT_INDEX 1
 # define ASAN_INTERCEPT_PTHREAD_CREATE 1
 # define ASAN_INTERCEPT_FORK 1
if ((!INTERCEPT_FUNCTION_VER(name, ver) || !REAL(name)))                   \
       VReport(                                                                 \
           1, "AddressSanitizer: failed to intercept '" #name "@@" #ver "'\n"); \
   } while (0)
 #else
 // OS X interceptors don't need to be initialized with INTERCEPT_FUNCTION.
 #define ASAN_INTERCEPT_FUNC(name)
 #endif  // SANITIZER_MAC
 
-namespace __asan {
-
-void InitializeAsanInterceptors();
-void InitializePlatformInterceptors();
-
-#define ENSURE_ASAN_INITED() do { \
-  CHECK(!asan_init_is_running); \
-  if (UNLIKELY(!asan_inited)) { \
-    AsanInitFromRtl(); \
-  } \
-} while (0)
-
-}  // namespace __asan
+#endif  // !SANITIZER_FUCHSIA
 
 #endif  // ASAN_INTERCEPTORS_H

lib/asan/asan_interceptors.cc

 #include "asan_poisoning.h"
 #include "asan_report.h"
 #include "asan_stack.h"
 #include "asan_stats.h"
 #include "asan_suppressions.h"
 #include "lsan/lsan_common.h"
 #include "sanitizer_common/sanitizer_libc.h"
 
+// There is no general interception at all on Fuchsia.
+// Only the functions in asan_interceptors_memintrinsics.cc are
+// really defined to replace libc functions.
+#if !SANITIZER_FUCHSIA
+
 #if SANITIZER_POSIX
 #include "sanitizer_common/sanitizer_posix.h"
 #endif
 
 #if defined(__i386) && SANITIZER_LINUX
 #define ASAN_PTHREAD_CREATE_VERSION "GLIBC_2.1"
 #elif defined(__mips__) && SANITIZER_LINUX
 #define ASAN_PTHREAD_CREATE_VERSION "GLIBC_2.2"

 #endif
 
   InitializePlatformInterceptors();
 
   VReport(1, "AddressSanitizer: libc interceptors initialized\n");
 }
 
 } // namespace __asan
+
+#endif // !SANITIZER_FUCHSIA

lib/asan/asan_interceptors_memintrinsics.cc

 
 void *__asan_memset(void *block, int c, uptr size) {
   ASAN_MEMSET_IMPL(nullptr, block, c, size);
 }
 
 void *__asan_memmove(void *to, const void *from, uptr size) {
   ASAN_MEMMOVE_IMPL(nullptr, to, from, size);
 }
+
+#if SANITIZER_FUCHSIA
+
+// Fuchsia doesn't use sanitizer_common_interceptors.inc, but the only
+// things there it wants are these three.  Just define them as aliases
+// here rather than repeating the contents.
+
+decltype(memcpy) memcpy [[gnu::alias("__asan_memcpy")]];
+decltype(memmove) memmove [[gnu::alias("__asan_memmove")]];
+decltype(memset) memset [[gnu::alias("__asan_memset")]];
+
+#endif // SANITIZER_FUCHSIA