[sanitizer] Split GetMaxVirtualAddress into separate Linux version and Mac version [NFC]

[kubamracek]

Summary

The logic in GetMaxVirtualAddress is already pretty complex, and I want to get rid of the hardcoded value for iOS/AArch64, which would need adding more Darwin-specific code, so let's split the implementation into sanitizer_linux.cc and sanitizer_mac.cc files. NFC.

[kubamracek]

Fixup in r307282.

[kubamracek]

More Linux fixup: r307284

compiler-rt/trunk/lib/sanitizer_common/sanitizer_linux.cc

if (internal_iserror(bytes_read_)) {
     return false;
   } else if (bytes_read_ == 0) {
     return false;
   }
   entry_ = (struct linux_dirent *)buffer_.data();
   return true;
 }
 
+uptr GetMaxVirtualAddress() {
+#if SANITIZER_WORDSIZE == 64
+# if defined(__powerpc64__) || defined(__aarch64__)
+  // On PowerPC64 we have two different address space layouts: 44- and 46-bit.
+  // We somehow need to figure out which one we are using now and choose
+  // one of 0x00000fffffffffffUL and 0x00003fffffffffffUL.
+  // Note that with 'ulimit -s unlimited' the stack is moved away from the top
+  // of the address space, so simply checking the stack address is not enough.
+  // This should (does) work for both PowerPC64 Endian modes.
+  // Similarly, aarch64 has multiple address space layouts: 39, 42 and 47-bit.
+  return (1ULL << (MostSignificantSetBitIndex(GET_CURRENT_FRAME()) + 1)) - 1;
+# elif defined(__mips64)
+  return (1ULL << 40) - 1;  // 0x000000ffffffffffUL;
+# elif defined(__s390x__)
+  return (1ULL << 53) - 1;  // 0x001fffffffffffffUL;
+# else
+  return (1ULL << 47) - 1;  // 0x00007fffffffffffUL;
+# endif
+#else  // SANITIZER_WORDSIZE == 32
+# if defined(__s390__)
+  return (1ULL << 31) - 1;  // 0x7fffffff;
+# else
+  uptr res = (1ULL << 32) - 1;  // 0xffffffff;
+  if (!common_flags()->full_address_space)
+    res -= GetKernelAreaSize();
+  CHECK_LT(reinterpret_cast<uptr>(&res), res);
+  return res;
+# endif
+#endif  // SANITIZER_WORDSIZE
+}
+
 uptr GetPageSize() {
 // Android post-M sysconf(_SC_PAGESIZE) crashes if called from .preinit_array.
 #if SANITIZER_ANDROID
   return 4096;
 #elif SANITIZER_LINUX && (defined(__x86_64__) || defined(__i386__))
   return EXEC_PAGESIZE;
 #elif SANITIZER_USE_GETAUXVAL
   return getauxval(AT_PAGESZ);

compiler-rt/trunk/lib/sanitizer_common/sanitizer_mac.cc

void MaybeReexec() {
   LeakyResetEnv(kDyldInsertLibraries, new_env);
 }
 #endif  // SANITIZER_GO
 
 char **GetArgv() {
   return *_NSGetArgv();
 }
 
+uptr GetMaxVirtualAddress() {
+#if SANITIZER_WORDSIZE == 64
+# if defined(__aarch64__) && SANITIZER_IOS && !SANITIZER_IOSSIM
+  // Ideally, we would derive the upper bound from MACH_VM_MAX_ADDRESS. The
+  // upper bound can change depending on the device.
+  return 0x200000000 - 1;
+# else
+  return (1ULL << 47) - 1;  // 0x00007fffffffffffUL;
+# endif
+#else  // SANITIZER_WORDSIZE == 32
+  return (1ULL << 32) - 1;  // 0xffffffff;
+#endif  // SANITIZER_WORDSIZE
+}
+
 uptr FindAvailableMemoryRange(uptr shadow_size,
                               uptr alignment,
                               uptr left_padding) {
   typedef vm_region_submap_short_info_data_64_t RegionInfo;
   enum { kRegionInfoSize = VM_REGION_SUBMAP_SHORT_INFO_COUNT_64 };
   // Start searching for available memory region past PAGEZERO, which is
   // 4KB on 32-bit and 4GB on 64-bit.
   mach_vm_address_t start_address =

compiler-rt/trunk/lib/sanitizer_common/sanitizer_posix.cc

#endif  // SANITIZER_ANDROID
   // Top gigabyte is reserved for kernel.
   return gbyte;
 #else
   return 0;
 #endif  // SANITIZER_LINUX && !SANITIZER_X32
 }
 #endif  // SANITIZER_WORDSIZE == 32
 
-uptr GetMaxVirtualAddress() {
-#if SANITIZER_WORDSIZE == 64
-# if defined(__aarch64__) && SANITIZER_IOS && !SANITIZER_IOSSIM
-  // Ideally, we would derive the upper bound from MACH_VM_MAX_ADDRESS. The
-  // upper bound can change depending on the device.
-  return 0x200000000 - 1;
-# elif defined(__powerpc64__) || defined(__aarch64__)
-  // On PowerPC64 we have two different address space layouts: 44- and 46-bit.
-  // We somehow need to figure out which one we are using now and choose
-  // one of 0x00000fffffffffffUL and 0x00003fffffffffffUL.
-  // Note that with 'ulimit -s unlimited' the stack is moved away from the top
-  // of the address space, so simply checking the stack address is not enough.
-  // This should (does) work for both PowerPC64 Endian modes.
-  // Similarly, aarch64 has multiple address space layouts: 39, 42 and 47-bit.
-  return (1ULL << (MostSignificantSetBitIndex(GET_CURRENT_FRAME()) + 1)) - 1;
-# elif defined(__mips64)
-  return (1ULL << 40) - 1;  // 0x000000ffffffffffUL;
-# elif defined(__s390x__)
-  return (1ULL << 53) - 1;  // 0x001fffffffffffffUL;
-# else
-  return (1ULL << 47) - 1;  // 0x00007fffffffffffUL;
-# endif
-#else  // SANITIZER_WORDSIZE == 32
-# if defined(__s390__)
-  return (1ULL << 31) - 1;  // 0x7fffffff;
-# else
-  uptr res = (1ULL << 32) - 1;  // 0xffffffff;
-  if (!common_flags()->full_address_space)
-    res -= GetKernelAreaSize();
-  CHECK_LT(reinterpret_cast<uptr>(&res), res);
-  return res;
-# endif
-#endif  // SANITIZER_WORDSIZE
-}
-
 void *MmapOrDie(uptr size, const char *mem_type, bool raw_report) {
   size = RoundUpTo(size, GetPageSizeCached());
   uptr res = internal_mmap(nullptr, size,
                            PROT_READ | PROT_WRITE,
                            MAP_PRIVATE | MAP_ANON, -1, 0);
   int reserrno;
   if (UNLIKELY(internal_iserror(res, &reserrno)))
     ReportMmapFailureAndDie(size, mem_type, "allocate", reserrno, raw_report);