This hook returns a pointer to the data needed by
TARGET_PCH_VALID_P and sets
‘*sz’ to the size of the data in bytes.
This hook checks whether the options used to create a PCH file are
compatible with the current settings. It returns
if so and a suitable error message if not. Error messages will
be presented to the user and must be localized using ‘_(msg)’.
data is the data that was returned by
when the PCH file was created and sz is the size of that data in bytes.
It’s safe to assume that the data was created by the same version of the
compiler, so no format checking is needed.
The default definition of
default_pch_valid_p should be
suitable for most targets.
If this hook is nonnull, the default implementation of
TARGET_PCH_VALID_P will use it to check for compatible values
target_flags. pch_flags specifies the value that
target_flags had when the PCH file was created. The return
value is the same as for
Called before writing out a PCH file. If the target has some garbage-collected data that needs to be in a particular state on PCH loads, it can use this hook to enforce that state. Very few targets need to do anything here.