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author | Sean Silva <silvas@purdue.edu> | 2012-10-11 23:31:18 +0000 |
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committer | Sean Silva <silvas@purdue.edu> | 2012-10-11 23:31:18 +0000 |
commit | 886e7f8cbb45eed3381aaaca80098473259768cf (patch) | |
tree | 9ae6e4d6ece3a63de76745fb759085b3b2bba450 /clang/lib/Rewrite/Core/RewriteRope.cpp | |
parent | d7802ad8a5fa05a386597a09c32543804e4c8edd (diff) | |
download | bcm5719-llvm-886e7f8cbb45eed3381aaaca80098473259768cf.tar.gz bcm5719-llvm-886e7f8cbb45eed3381aaaca80098473259768cf.zip |
Add missing classof().
Somewhat troublingly, without this implemented, the check inside
isa_impl<> would silently use the parent's `classof()` when determining
whether it was okay to downcast from the parent to the child!
Bug analysis:
A build failure after removing the parent's `classof()` initially
alerted me to the bug, after which a little bit of thinking and reading
of the code identified the root cause.
The compiler could be made to prevent this bug from happening if there
were a way to ensure that in the code
template <typename To, typename From, typename Enabler = void>
struct isa_impl {
static inline bool doit(const From &Val) {
return To::classof(&Val);
}
};
that `To::classof` is actually inside the class `To`, and not in a base
class. I am not aware of a way to check this in C++. If there is a means
to perform that check, please bring it up on the list and this will be
fixed.
There is a high likelihood that there are other instances of this same
bug in the codebase.
llvm-svn: 165769
Diffstat (limited to 'clang/lib/Rewrite/Core/RewriteRope.cpp')
0 files changed, 0 insertions, 0 deletions