Add exc_client_variants (UniversalRaiseException()) and its test

util/mach/mach_extensions.h

 // Copyright 2014 The Crashpad Authors. All rights reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
@@ skipping 10 matching lines @@
 
 //! \brief `MACH_PORT_NULL` with the correct type for a Mach port,
 //!     `mach_port_t`.
 //!
 //! For situations where implicit conversions between signed and unsigned types
 //! are not performed, use kMachPortNull instead of an explicit `static_cast` of
 //! `MACH_PORT_NULL` to `mach_port_t`. This is useful for logging and testing
 //! assertions.
 const mach_port_t kMachPortNull = MACH_PORT_NULL;
 
+//! \brief `MACH_EXCEPTION_CODES` with the correct type for a Mach exception
+//!     behavior, `exception_behavior_t`.
+//!
+//! Signedness problems can occur when ORing `MACH_EXCEPTION_CODES` as a signed
+//! integer, because a signed integer overflow results. This constant can be
+//! used instead of `MACH_EXCEPTION_CODES` in such cases.
+const exception_behavior_t kMachExceptionCodes = MACH_EXCEPTION_CODES;
+
 // Because exception_mask_t is an int and has one bit for each defined
 // exception_type_t, it’s reasonable to assume that there cannot be any
 // officially-defined exception_type_t values higher than 31.
 // kMachExceptionSimulated uses a value well outside this range because it does
 // not require a corresponding mask value. Simulated exceptions are delivered to
 // the exception handler registered for EXC_CRASH exceptions using
 // EXC_MASK_CRASH.
 
 //! \brief An exception type to use for simulated exceptions.
 const exception_type_t kMachExceptionSimulated = 'CPsx';
 
+//! \brief Like `mach_thread_self()`, but without the obligation to release the
+//!     send right.
+//!
+//! `mach_thread_self()` returns a send right to the current thread port,
+//! incrementing its reference count. This burdens the caller with maintaining
+//! this send right, and calling `mach_port_deallocate()` when it is no longer
+//! needed. This is burdensome, and is at odds with the normal operation of
+//! `mach_task_self()`, which does not increment the task port’s reference count
+//! whose result must not be deallocated.
+//!
+//! Callers can use this function in preference to `mach_thread_self()`. This
+//! function returns an extant reference to the current thread’s port without
+//! incrementing its reference count.
+//!
+//! \return The value of `mach_thread_self()` without incrementing its reference
+//!     count. The returned port must not be deallocated by
+//!     `mach_port_deallocate()`. The returned value is valid as long as the
+//!     thread continues to exist as a `pthread_t`.
+mach_port_t MachThreadSelf();
+
 }  // namespace crashpad
 
 #endif  // CRASHPAD_UTIL_MACH_MACH_EXTENSIONS_H_