[cfe-dev] PCHReader: Header search info and FileManager::NextFileUID

[Zhongxing Xu]

2009/6/8 Douglas Gregor <dgregor at apple.com>:
>
> On Jun 7, 2009, at 10:48 PM, Zhongxing Xu wrote:
>
>> 2009/6/8 Zhongxing Xu <xuzhongxing at gmail.com>:
>>>
>>> Hi,
>>>
>>> After HeaderSearchInfo is recovered in
>>> PCHReader::ReadSourceManagerBlock(), we actually have used some UIDs
>>> (recorded by NumHeaderInfos). But at this time the NextFileUID in
>>> FileManager is still 0. Call to FileManager::getFile() could use that
>>> FileUID for a different file than the header in HeaderSearch. Would
>>> this inconsistency cause problems?
>>
>> After reading some more code, my understanding is that all file source
>> locations are then preloaded and FileManager is restored to the
>> appropriate state.
>
> Yes, we preload all file source locations. We may be able to decrease PCH
> load times slightly by not preloading them, but it's not something that ever
> came up in a profile so I doubt it's important.

I think we have to preload them to bind the correct UIDs to the header
files? Otherwise FileManager may use UIDs for different files than the
files in HeaderSearchInfo.