[PATCH] D38061: Set AnonymousTagLocations false for ASTContext if column info is expected not to be used

[Wenlei He via Phabricator via cfe-commits]

wenlei added a comment.

In D38061#1484486 <https://reviews.llvm.org/D38061#1484486>, @dblaikie wrote:

> Seems like the right thing would be for the DWARF code that wants a rendered type name to pass its own printing policy, rather than changing some relatively global one.
>
> (though also I have my doubts about the whole approach - macro expansion can change the line number as well as the column number, so only suppressing column number would be insufficient - and this also reduces the usability for users (because the file/line/column of an anonymous type is a useful debugging aid). Seems to me like this should be opt-in if it's supported at all - though ideally build systems would use -frewrite-includes rather than full preprocessing, and then macros and lines/columns would be preserved, I think)


Line number is ok because preprocessor also inserts #linemarker, and later on these markers are used to recover the original line number before macro expansion. Column is problematic, as there's nothing like a column marker (if possible at all) so there's no way to see through the column change from macro expansion. We tried -frewrite-includes too, but it has its own issues - without macro expansion, it bloats the file size that needs to send to distcc remote machine significantly.


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https://reviews.llvm.org/D38061