[compiler-rt] Return correct size of struct pthread for glibc-2.12.2

[Hahnfeld]

Summary

There seems to be a difference between 2.12.1 and 2.12.2 in 64-bit build.
Tested on Scientific Linux 6.6, based on RHEL.

[samsonov]

LGTM

lib/sanitizer_common/sanitizer_linux_libcdep.cc

246

Just else if (minor <= 13) ?

lib/sanitizer_common/sanitizer_linux_libcdep.cc

 #if defined(__x86_64__) || defined(__i386__)
 #ifdef _CS_GNU_LIBC_VERSION
   char buf[64];
   uptr len = confstr(_CS_GNU_LIBC_VERSION, buf, sizeof(buf));
   if (len < sizeof(buf) && internal_strncmp(buf, "glibc 2.", 8) == 0) {
     char *end;
     int minor = internal_simple_strtoll(buf + 8, &end, 10);
     if (end != buf + 8 && (*end == '\0' || *end == '.')) {
+      int patch = 0;
+      if (*end == '.')
+        // strtoll will return 0 if no valid conversion could be performed
+        patch = internal_simple_strtoll(end + 1, nullptr, 10);
+
       /* sizeof(struct pthread) values from various glibc versions.  */
       if (SANITIZER_X32)
         val = 1728;  // Assume only one particular version for x32.
       else if (minor <= 3)
         val = FIRST_32_SECOND_64(1104, 1696);
       else if (minor == 4)
         val = FIRST_32_SECOND_64(1120, 1728);
       else if (minor == 5)
         val = FIRST_32_SECOND_64(1136, 1728);
       else if (minor <= 9)
         val = FIRST_32_SECOND_64(1136, 1712);
       else if (minor == 10)
         val = FIRST_32_SECOND_64(1168, 1776);
-      else if (minor <= 12)
+      else if (minor == 11 || (minor == 12 && patch == 1))
         val = FIRST_32_SECOND_64(1168, 2288);
-      else if (minor == 13)
+      // take patch = 0 as latest version (valid for RHEL 6)
+      else if ((minor == 12 && patch != 1) || minor == 13)
         val = FIRST_32_SECOND_64(1168, 2304);
       else
         val = FIRST_32_SECOND_64(1216, 2304);
     }
     if (val)
       atomic_store(&kThreadDescriptorSize, val, memory_order_relaxed);
     return val;
   }