[compiler-rt] Add internal wcslen to avoid crashing on windows 64-bits

[etienneb]

Summary

The function wcslen is incorrectly hooked on windows 64-bits.

The interception library is not able to hook without breaking the code.
The function is too small and the interception must be done with
trampoline-hooking which turned out to be incorrect on a small
loop (first few instructions have a backedge).

[rnk]

lgtm

lib/asan/asan_win_dll_thunk.cc

384 ↗

(On Diff #63985)

unrelated?

[etienneb]

remove useless change

[etienneb]

right fix

[rnk]

lib/asan/asan_interceptors.cc

588

Eh, I don't think we need an ifdef, we can always use internal_wcslen. Better to be consistent. Nobody uses wcslen on Unix anyway. We added this interceptor for Windows.

[etienneb]

In D22363#484241, @rnk wrote:

lgtm

lib/asan/asan_interceptors.cc

588

landed here: Committed revision 275492.

lib/asan/asan_win_dll_thunk.cc

384 ↗

(On Diff #63985)

Bad patch editing.
This is the next patch.

lib/asan/asan_interceptors.cc

INTERCEPTOR(char*, __strdup, const char *s) {
   REAL(memcpy)(new_mem, s, length + 1);
   return reinterpret_cast<char*>(new_mem);
 }
 #endif // ASAN_INTERCEPT___STRDUP
 
 INTERCEPTOR(SIZE_T, wcslen, const wchar_t *s) {
   void *ctx;
   ASAN_INTERCEPTOR_ENTER(ctx, wcslen);
+#if SANITIZER_WINDOWS64
+  // The function is incorrectly hooked on windows 64-bit.
+  SIZE_T length = internal_wcslen(s);
+#else
   SIZE_T length = REAL(wcslen)(s);
+#endif
   if (!asan_init_is_running) {
     ENSURE_ASAN_INITED();
     ASAN_READ_RANGE(ctx, s, (length + 1) * sizeof(wchar_t));
   }
   return length;
 }
 
 INTERCEPTOR(char*, strncpy, char *to, const char *from, uptr size) {

lib/sanitizer_common/sanitizer_libc.h

 uptr internal_strlcat(char *dst, const char *src, uptr maxlen);
 char *internal_strncat(char *dst, const char *src, uptr n);
 int internal_strncmp(const char *s1, const char *s2, uptr n);
 uptr internal_strlcpy(char *dst, const char *src, uptr maxlen);
 char *internal_strncpy(char *dst, const char *src, uptr n);
 uptr internal_strnlen(const char *s, uptr maxlen);
 char *internal_strrchr(const char *s, int c);
 // This is O(N^2), but we are not using it in hot places.
+uptr internal_wcslen(const wchar_t *s);
 char *internal_strstr(const char *haystack, const char *needle);
 // Works only for base=10 and doesn't set errno.
 s64 internal_simple_strtoll(const char *nptr, char **endptr, int base);
 int internal_snprintf(char *buffer, uptr length, const char *format, ...);
 
 // Return true if all bytes in [mem, mem+size) are zero.
 // Optimized for the case when the result is true.
 bool mem_is_zero(const char *mem, uptr size);

lib/sanitizer_common/sanitizer_libc.cc

char *internal_strstr(const char *haystack, const char *needle) {
   if (len1 < len2) return nullptr;
   for (uptr pos = 0; pos <= len1 - len2; pos++) {
     if (internal_memcmp(haystack + pos, needle, len2) == 0)
       return const_cast<char *>(haystack) + pos;
   }
   return nullptr;
 }
 
+uptr internal_wcslen(const wchar_t *s) {
+  uptr i = 0;
+  while (s[i]) i++;
+  return i;
+}
+
 s64 internal_simple_strtoll(const char *nptr, char **endptr, int base) {
   CHECK_EQ(base, 10);
   while (IsSpace(*nptr)) nptr++;
   int sgn = 1;
   u64 res = 0;
   bool have_digits = false;
   char *old_nptr = const_cast<char *>(nptr);
   if (*nptr == '+') {