285627 - mddepend.pl is inefficient

Status: RESOLVED FIXED

(Firefox Build System :: General, defect)

Description

[[e-mail]]

I noticed that a Windows build that I spun up was taking hours to build tier_9
on a PIII 1133Mhz. Further investigation showed that it was spending most of its
time running mddepend.pl. My RH7.3 .deps/<olj>.pp files have the format
<obj>: header header \
  header ...
while the ones on my Windows build have the format
<obj>: header
<obj>: header
...
The latter format makes mddpend.pl stat <obj> once fot every header file, even
though the <obj> has been shown to be out of date.

Comment 1

[[e-mail]]

Attachment: The fix

* Changes <STDIN> to <> to avoid an unnecessary invocation of cat
* Changes @alldeps to a hash so multiple obj: lines can be merged
* Write .all.pp in textmode because that's how we read it earlier

Comment 2

[[e-mail]]

Sadly I only have a low resolution timer handy but in parser/htmlparser/src it
took over 10 minutes to run mddepend before the patch and less than 1 after.

Comment 3

[Benjamin Smedberg]

Comment on attachment 177045 [details] [diff] [review]
The fix

Beautiful.

Comment 4

[[e-mail]]

Fix checked in.