arch: Add a "set" function to set one PCState to another.
Most of the time, the type pointed to by a PCState pointer or reference
will be the same as all the others, if not nullptr.
This change adds a set of "set" functions which assume that the
underlying type of each pointer or reference are the same, and handles
casting, copying things over, creating a new copy, etc, for you. It uses
a new "update" virtual method on PCState subclasses which casts the
source to the same type as the destination and copies values over.
Note that the "set" function doesn't actually verify that the two types
are the same, just like the overloaded ==, != and << operators. In the
future, those checks can be added for debugging purposes, probably
guarded by a configuration variable which can be toggled on or off to
get better performance or more thorough error checking.
The main advantage of these wrappers are that they allows consistent
semantics whether your moving a value from a pointer, or from a yet
unconverted PCState subclass, or vice versa, which will be particularly
helpful while transitioning between using raw PCState instances and
using primarily pointers and references.
This change also adds wrappers which handle std::unique_ptr, which makes
it easier to use them as arguments to these functions. Otherwise, if the
std::unique_ptr is a temporary value, using the return value of .get()
will let the std::unique_ptr go out of scope, making it delete the data
pointed to by the returned pointed. By keeping the std::unique_ptr
around on the stack, that prevents it from going out of scope.
Change-Id: I2c737b08e0590a2c46e212a7b9efa543bdb81ad3
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/52041
Tested-by: kokoro <noreply+kokoro@google.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
5 files changed
