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authorMichael Meeks <michael.meeks@collabora.com>2017-01-07 21:48:56 +0000
committerAndras Timar <andras.timar@collabora.com>2017-02-17 23:47:08 +0100
commit2b3c44144ebcce424f8e5ad23e10bc2a0733b0f9 (patch)
tree629c0df97c60dbbd0e372ab74b25293b9cbee2db /unusedcode.README
parentfdef726607a3512829c17c6c306f608f69cde1f7 (diff)
Update call-catcher readme.
Change-Id: I777f05a66038ada8aff9a65637475b56ebbf5ad9 (cherry picked from commit f57dd1e34caa4f5e92490fbebdca0ddce256ad54)
Diffstat (limited to 'unusedcode.README')
-rw-r--r--unusedcode.README20
1 files changed, 6 insertions, 14 deletions
diff --git a/unusedcode.README b/unusedcode.README
index e95723864982..a0c4d3b7208a 100644
--- a/unusedcode.README
+++ b/unusedcode.README
@@ -11,30 +11,23 @@ Code listed as unused is code that gcc outputs but that nothing calls
a) It's possible that some other platform or configuration uses the code,
so manual inspection is always required.
-b) At the time of writing the majority of unused code now originates via
- macros, mostly from pre-STL containers, see [2] for killing two birds
- with one stone. These are typically methods of signatures...
- *::Insert
- *::Remove
- *::DeleteAndDestroy
- *::Replace
-c) callcatcher ignores virtuals. But implementations of "pure virtuals"
+b) callcatcher ignores virtuals. But implementations of "pure virtuals"
are not actually virtual methods. If something is declared pure virtual
and provides an impl and that base-class impl is not explicitly called
anywhere, then that impl can go away.
-d) gcc will only emit code for inlines if those inlines are used, so
+c) gcc will only emit code for inlines if those inlines are used, so
sometimes something is listed correctly as unused but some inline
- code takes a pointer or reference to something which cannot be
+ code takes a pointer or reference to something which cannot be
instantiated so removal of some method/class fails at build time because
gcc never emits any code for the unused inline but trips over it at
compile time after an attempt at removal. i.e. generally the inline method
can go as well because nothing calls it either, a double win.
-e) if a constructor is listed as unused, and it's the *only* ctor in the class,
+d) if a constructor is listed as unused, and it's the *only* ctor in the class,
then no object of that class can be constructed, so the whole thing is
unused, which can lead to a whole cascade of tricky but logical fallout.
-f) if a destructor is listed as unused, and a constructor isn't, then there's
+e) if a destructor is listed as unused, and a constructor isn't, then there's
a leak somewhere, and the destructor most likely *should* be called.
-g) there's more actually unused code then what's listed. The idea is that what's
+f) there's more actually unused code then what's listed. The idea is that what's
listed is definitely unused under the generation configuration, not that
it's a list of all unused code. If the count of unused easy hits 0 then
we can have a look at the non-easy and if that hits 0, then strip out
@@ -44,4 +37,3 @@ g) there's more actually unused code then what's listed. The idea is that what's
Symbols that are known to be false alarms are listed in: unusedcode.exclude
[1] http://www.skynet.ie/~caolan/Packages/callcatcher.html
-[2] https://bugs.libreoffice.org/show_bug.cgi?id=38832