Summary: This makes the default constructor implicitly constexpr and noexcept.
Reviewers: zturner, beanz
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D27094
llvm-svn: 288131
This is a bit too aggressive of a warning, as it is forces
ANY function which returns a StringRef to have its return
value checked. While useful on classes like llvm::Error which
are designed to require checking, this is not the case for
StringRef, and it is perfectly reasonable to have a function
return a StringRef for which the return value is not checked.
Move LLVM_NODISCARD to each of the individual member functions
where it makes sense instead.
llvm-svn: 287586
Similar to r283798, this prevents accidentally referring to temporary
storage that goes out of scope by the end of the statement:
someStringRef = getStringByValue();
someStringRef = (Twine("-") + otherString).str();
Note that once again the constructor still has this problem:
StringRef someStringRef = getStringByValue();
because once again we occasionally rely on this in calls:
takesStringRef(getStringByValue());
takesStringRef(Twine("-") + otherString);
Still, it's a step.
llvm-svn: 286139
Instead of annotating (most of) the StringRef API, we can just
annotate the type directly. This is less code and it will warn in more
cases.
llvm-svn: 284364
This adds 4 new functions to StringRef, which can be used to
take or drop characters while a certain condition is met, or
until a certain condition is met. They are:
take_while - Return characters until a condition is not met.
take_until - Return characters until a condition is met.
drop_while - Remove characters until a condition is not met.
drop_until - Remove characters until a condition is met.
Internally, all of these functions delegate to two additional
helper functions which can be used to search for the position
of a character meeting or not meeting a condition, which are:
find_if - Find the first character matching a predicate.
find_if_not - Find the first character not matching a predicate.
Differential Revision: https://reviews.llvm.org/D24842
llvm-svn: 282346
StringRef::getInteger() exists and treats the entire string as
an integer of the specified radix, failing if any invalid characters
are encountered or the number overflows.
Sometimes you might have something like "123456foo" and you want
to get the number 123456 and leave the string "foo" remaining.
This is similar to what would be possible by using the standard
runtime library functions strtoul et al and specifying an end
pointer.
This patch adds consumeInteger(), which does exactly that. It
consumes as much as possible until an invalid character is found,
and modifies the StringRef in place so that upon return only
the portion of the StringRef after the number remains.
Differential Revision: https://reviews.llvm.org/D24778
llvm-svn: 282164
When porting large bodies of code from using const char*
to StringRef, it is helpful to be able to treat nullptr
as an empty string, since that it is often what it is used
to indicate in C-style code.
Differential Revision: https://reviews.llvm.org/D24697
llvm-svn: 281906
are very handy when parsing text.
They are essentially a combination of startswith and a self-modifying
drop_front, or endswith and drop_back respectively.
Differential Revision: https://reviews.llvm.org/D22723
llvm-svn: 277288
Summary:
Functions like "slice" and "drop_front" sound like they might mutate the
underlying object, but they don't. Warning on unused results would have
saved me an hour yesterday, and I'm sure I'm not the only one.
LLVM and Clang are clean wrt this warning after D22540.
Reviewers: majnemer
Subscribers: sanjoy, chandlerc, llvm-commits
Differential Revision: https://reviews.llvm.org/D22541
llvm-svn: 276058
The BumpPtrAllocator currently doesn't handle zero length allocations well.
The discussion for how to fix that is ongoing. However, there's no need
for StringRef::copy to actually allocate anything here anyway, so just
return StringRef() when we get a zero length copy.
Reviewed by David Blaikie
llvm-svn: 264201
Add support for trimming a single kind of character from a StringRef.
This makes the common case of trimming null bytes much neater. It's also
probably a bit speedier too, since it avoids creating a std::bitset in
find_{first,last}_not_of.
llvm-svn: 260925
Based on conversations with Justin and a few others, these constructors
are really useful to have in the executable so that you can call them
from the debugger. After some measurements, these *particular* calls
aren't so problematic as to make them a good tradeoff for always inline.
Please let me know if there are other functions really needed for
debugging. The always inline attribute is a hack that we should only
really employ when it doesn't hurt.
llvm-svn: 248188
The logic of this follows something Howard does in libc++ and something
I discussed with Chris eons ago -- for a lot of functions, there is
really no benefit to preserving "debug information" by leaving the
out-of-line even in debug builds. This is especially true as we now do
a very good job of preserving most debug information even in the face of
inlining. There are a bunch of methods in StringRef that we are paying
a completely unacceptable amount for with every debug build of every
LLVM developer.
Some day, we should fix Clang/LLVM so that developers can reasonable
use a default of something other than '-O0' and not waste their lives
waiting on *completely* unoptimized code to execute. We should have
a default that doesn't impede debugging while providing at least
plausable performance.
But today is not that day.
So today, I'm applying always_inline to the functions that are really
hurting the critical path for stuff like 'check_llvm'. I'm being very
cautious here, but there are a few other APIs that we really should do
this for as a matter of pragmatism. Hopefully we can rip this out some
day.
With this change, TripleTest.Normalization runtime decreases by over
10%, and the total 'check-llvm' time on my 48-core box goes from 38s to
just under 37s.
llvm-svn: 247253
with the StringRef::split method when used with a MaxSplit argument
other than '-1' (which nobody really does today, but which should
actually work).
The spec claimed both to split up to MaxSplit times, but also to append
<= MaxSplit strings to the vector. One of these doesn't make sense.
Given the name "MaxSplit", let's go with it being a max over how many
*splits* occur, which means the max on how many strings get appended is
MaxSplit+1. I'm not actually sure the implementation correctly provided
this logic either, as it used a really opaque loop structure.
The implementation was also playing weird games with nullptr in the data
field to try to rely on a totally opaque hidden property of the split
method that returns a pair. Nasty IMO.
Replace all of this with what is (IMO) simpler code that doesn't use the
pair returning split method, and instead just finds each separator and
appends directly. I think this is a lot easier to read, and it most
definitely matches the spec. Added some tests that exercise the corner
cases around StringRef() and StringRef("") that all now pass.
I'll start using this in code in the next commit.
llvm-svn: 247249
on StringRef. Finding and splitting on a single character is
substantially faster than doing it on even a single character StringRef
-- we immediately get to a *very* tuned memchr call this way.
Even nicer, we get to this even in a debug build, shaving 18% off the
runtime of TripleTest.Normalization, helping PR23676 some more.
llvm-svn: 247244
The patch is generated using this command:
tools/clang/tools/extra/clang-tidy/tool/run-clang-tidy.py -fix \
-checks=-*,llvm-namespace-comment -header-filter='llvm/.*|clang/.*' \
llvm/lib/
Thanks to Eugene Kosov for the original patch!
llvm-svn: 240137
Modern libc's have an SSE version of memchr which is a lot faster than our
hand-rolled version. In the past I was reluctant to use it because Darwin's
memchr used a naive ridiculously slow implementation, but that has been fixed
some versions ago.
Should have zero functional impact.
llvm-svn: 232898
`MDString`s can have arbitrary characters in them. Prevent an assertion
that fired in `BitcodeWriter` because of sign extension by copying the
characters into the record as `unsigned char`s.
Based on a patch by Keno Fischer; fixes PR21882.
llvm-svn: 224077
Fix http://llvm.org/PR21158 by adding a cast to unsigned long long,
so the comparison would be between two unsigned long longs instead
of bool and unsigned long long.
if (getAsUnsignedInteger(*this, Radix, ULLVal) ||
static_cast<unsigned long long>(static_cast<T>(ULLVal)) != ULLVal)
llvm-svn: 219065
Doesn't make sense to restrict this to BumpPtrAllocator. While there
replace an explicit loop with std::equal. Some standard libraries know
how to compile this down to a ::memcmp call if possible.
llvm-svn: 206615
There are a couple of interesting things here that we want to check over
(particularly the expecting asserts in StringRef) and get right for general use
in ADT so hold back on this one. For clang we have a workable templated
solution to use in the meanwhile.
This reverts commit r200187.
llvm-svn: 200194
StringRef is a low-level data wrapper that shouldn't know about language
strings like 'true' and 'false' whereas StringExtras is just the place for
higher-level utilities.
llvm-svn: 200188
(1) Add llvm_expect(), an asserting macro that can be evaluated as a constexpr
expression as well as a runtime assert or compiler hint in release builds. This
technique can be used to construct functions that are both unevaluated and
compiled depending on usage.
(2) Update StringRef using llvm_expect() to preserve runtime assertions while
extending the same checks to static asserts in C++11 builds that support the
feature.
(3) Introduce ConstStringRef, a strong subclass of StringRef that references
compile-time constant strings. It's convertible to, but not from, ordinary
StringRef and thus can be used to add compile-time safety to various interfaces
in LLVM and clang that only accept fixed inputs such as diagnostic format
strings that tend to get misused.
llvm-svn: 200187
startswith_lower is ocassionally useful and I think worth adding.
endwith_lower is added for completeness.
Differential Revision: http://llvm-reviews.chandlerc.com/D2041
llvm-svn: 193706
r187874 seems to have been missed by the build bot infrastructure, and
the subsequent commits to compiler-rt don't seem to be queuing up new
build requsets. Hopefully this will.
As it happens, having the space here is the more common formatting. =]
llvm-svn: 187879
