[sanitizer] Use TASK_VM_INFO to get the maximum VM address on iOS/AArch64
We currently hardcode the maximum VM address on iOS/AArch64, which is not really correct and this value changes between device configurations. Let's use TASK_VM_INFO to retrieve the maximum VM address dynamically.
@@ -800,12 +800,36 @@ char **GetArgv() {
return *_NSGetArgv();
}
+#if defined(__aarch64__) && SANITIZER_IOS && !SANITIZER_IOSSIM
+// The task_vm_info struct is normally provided by the macOS SDK, but we need
+// fields only available in 10.12+. Declare the struct manually to be able to
+// build against older SDKs.
+struct __sanitizer_task_vm_info {
+ uptr _unused[(SANITIZER_WORDSIZE == 32) ? 20 : 19];
+ uptr min_address;
+ uptr max_address;
+};
+
+uptr GetTaskInfoMaxAddress() {
+ __sanitizer_task_vm_info vm_info = {{0}, 0, 0};
+ mach_msg_type_number_t count = sizeof(vm_info) / sizeof(int);
+ int err = task_info(mach_task_self(), TASK_VM_INFO, (int *)&vm_info, &count);
+ if (err == 0) {
+ return vm_info.max_address;
+ } else {
+ // xnu cannot provide vm address limit
+ return 0x200000000 - 1;
+ }
+}
+#endif
+
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;
+ // Get the maximum VM address
+ static uptr max_vm = GetTaskInfoMaxAddress();
+ CHECK(max_vm);
+ return max_vm;
# else
return (1ULL << 47) - 1; // 0x00007fffffffffffUL;
# endif
