There are actually two debug modes:
1. -D_LIBCPP_DEBUG2 or -D_LIBCPP_DEBUG2=1
This is a relatively expensive debug mode, but very thorough. This is normally what you want to debug with, but may turn O(1) operations into O(N) operations.
2. -D_LIBCPP_DEBUG2=0
This is "debug lite." Only preconditions that can be checked with O(1) expense are checked. For example range checking on an indexing operation. But not iterator validity.
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@187369 91177308-0d34-0410-b5e6-96231b3b80d8
unordered_set, however it is not complete yet for unordered_multiset,
unordered_map or unordered_multimap. There has been a lot of work done
for these other three containers, however that work was done just to
keep all of the tests passing.
You can try this out with -D_LIBCPP_DEBUG2. You will have to link to a
libc++.dylib that has been compiled with src/debug.cpp. So far, vector
(but not vector<bool>), list, and unordered_set are treated. I hope to
get the other three unordered containers up fairly quickly now that
unordered_set is done.
The flag _LIBCPP_DEBUG2 will eventually be changed to _LIBCPP_DEBUG, but
not today. This is my second effort at getting debug mode going for
libc++, and I'm not quite yet ready to throw all of the work under the
first attempt away.
The basic design is that all of the debug information is kept in a
central database, instead of in the containers. This has been done as
an attempt to have debug mode and non-debug mode be ABI compatible with
each other. There are some circumstances where if you construct a
container in an environment without debug mode and pass it into debug
mode, the checking will get confused and let you know with a readable
error message. Passing containers the other way: from debug mode out to
a non-debugging mode container should be 100% safe (at least that is the
goal).
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@186991 91177308-0d34-0410-b5e6-96231b3b80d8
