Summary:
UBSAN complains that this is undefined behavior.
We can assume that empty substring (N==1) always satisfy conditions. So
std::memcmp will be called only only for N > 1 and Str.size() > 0.
Reviewers: ruiu, zturner
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D26646
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@286910 91177308-0d34-0410-b5e6-96231b3b80d8
MSVC won't provide the body of this move constructor and assignment
operator, possibly because the copy constructor is banned. Just write
it manually.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@276685 91177308-0d34-0410-b5e6-96231b3b80d8
This prevents StringSwitch from being used with 'auto', which is
important because the inferred type is StringSwitch rather than the
result type. This is a problem because StringSwitch stores addresses
of temporary values rather than copying or moving the value into its
own storage.
This is a compromise that still allows wrapping StringSwitch in other
temporary structures, which (unlike StringSwitch) may be non-trivial
to set up and therefore want to at least be movable. (For an example,
see QueryParser.cpp in clang-tools-extra.)
Changing this uncovered the bug in PassBuilder, also in this patch.
Clang doesn't seem to have any occurrences of the issue.
Re-commit of r276652.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@276671 91177308-0d34-0410-b5e6-96231b3b80d8
This reverts commit r276652. The clang-query tool is currently
relying on this behavior. I'll try again later.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@276661 91177308-0d34-0410-b5e6-96231b3b80d8
...but most importantly, it cannot be used well with 'auto', because
the inferred type is StringSwitch rather than the result type. This
is a problem because StringSwitch stores addresses of temporary
values rather than copying or moving the value into its own storage.
Changing this uncovered the bug in PassBuilder, also in this patch.
Clang doesn't seem to have any occurrences of the issue.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@276652 91177308-0d34-0410-b5e6-96231b3b80d8
These are now quite heavily used in unit tests and the host tools,
making it worth having them be reasonably fast even in an unoptimized
build. This change reduces the total runtime of TripleTest.Normalization
by yet another 10% to 15%. It is now under 10 seconds on my machine, and
the total check-llvm time has dropped from 38s to around 36s.
I experimented with a number of different options, and the code pattern
here consistently seemed to lower the cleanest, likely due to the
significantly simple CFG and far fewer redundant tests of 'Result'.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247257 91177308-0d34-0410-b5e6-96231b3b80d8
This change removes the DefaultConstructible
and CopyAssignable constraints on the template
parameter T (the first one).
The second template parameter (R) is defaulted to be
identical to the first and controls the result type.
By specifying it to be (const T&) additionally the
CopyConstructible constraint on T can be removed.
This allows to use StringSwitch e.g. for llvm::Constant
instances.
Regarding the other review feedback regarding performance
because of taking pointers, this class should be completely
optimizable like before, since all methods are inline and
the pointer dereferencing and result value caching should be
possible behind the scenes by the "as-if" rule.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@91123 91177308-0d34-0410-b5e6-96231b3b80d8
