for loop if both members exist.
This resolves a DR whereby an errant 'begin' or 'end' member in a base
class could result in a derived class not being usable as a range with
non-member 'begin' and 'end'.
llvm-svn: 342925
Check each case value in turn while parsing it, performing the
conversion to the switch type within the context of the expression
itself. This will become necessary in order to properly handle cleanups
for temporaries created as part of the case label (in an upcoming
patch). For now it's just good hygiene.
This necessitates moving the checking for the switch condition itself to
earlier, so that the destination type is available when checking the
case labels.
As a nice side-effect, we get slightly improved diagnostic quality and
error recovery by separating the case expression checking from the case
statement checking and from tracking whether there are discarded case
labels.
llvm-svn: 338056
Basically, "AttributeList" loses all list-like mechanisms, ParsedAttributes is
switched to use a TinyPtrVector (and a ParsedAttributesView is created to
have a non-allocating attributes list). DeclaratorChunk gets the later kind,
Declarator/DeclSpec keep ParsedAttributes.
Iterators are added to the ParsedAttribute types so that for-loops work.
llvm-svn: 336945
Summary:
This is the second attempt of r333500 (Update NRVO logic to support early return).
The previous one was reverted for a miscompilation for an incorrect NRVO set up on templates such as:
```
struct Foo {};
template <typename T>
T bar() {
T t;
if (false)
return T();
return t;
}
```
Where, `t` is marked as non-NRVO variable before its instantiation. However, while its instantiation, it's left an NRVO candidate, turned into an NRVO variable later.
Reviewers: rsmith
Reviewed By: rsmith
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D47586
llvm-svn: 335019
Summary:
The previous implementation misses an opportunity to apply NRVO (Named Return Value
Optimization) below. That discourages user to write early return code.
```
struct Foo {};
Foo f(bool b) {
if (b)
return Foo();
Foo oo;
return oo;
}
```
That is, we can/should apply RVO for a local variable if:
* It's directly returned by at least one return statement.
* And, all reachable return statements in its scope returns the variable directly.
While, the previous implementation disables the RVO in a scope if there are multiple return
statements that refers different variables.
On the new algorithm, local variables are in NRVO_Candidate state at first, and a return
statement changes it to NRVO_Disabled for all visible variables but the return statement refers.
Then, at the end of the function AST traversal, NRVO is enabled for variables in NRVO_Candidate
state and refers from at least one return statement.
Reviewers: rsmith
Reviewed By: rsmith
Subscribers: xbolva00, Quuxplusone, arthur.j.odwyer, cfe-commits
Differential Revision: https://reviews.llvm.org/D47067
llvm-svn: 333500
This is similar to the LLVM change https://reviews.llvm.org/D46290.
We've been running doxygen with the autobrief option for a couple of
years now. This makes the \brief markers into our comments
redundant. Since they are a visual distraction and we don't want to
encourage more \brief markers in new code either, this patch removes
them all.
Patch produced by
for i in $(git grep -l '\@brief'); do perl -pi -e 's/\@brief //g' $i & done
for i in $(git grep -l '\\brief'); do perl -pi -e 's/\\brief //g' $i & done
Differential Revision: https://reviews.llvm.org/D46320
llvm-svn: 331834
enabled for the host.
If the compilation for the host enables C++ exceptions, but they are not
supported by the device, we still need to allow the code with the
exception handling constructs outside of the target regions.
llvm-svn: 331372
Summary:
This patch adds two new diagnostics, which are off by default:
**-Wreturn-std-move**
This diagnostic is enabled by `-Wreturn-std-move`, `-Wmove`, or `-Wall`.
Diagnose cases of `return x` or `throw x`, where `x` is the name of a local variable or parameter, in which a copy operation is performed when a move operation would have been available. The user probably expected a move, but they're not getting a move, perhaps because the type of "x" is different from the return type of the function.
A place where this comes up in the wild is `stdext::inplace_function<Sig, N>` which implements conversion via a conversion operator rather than a converting constructor; see https://github.com/WG21-SG14/SG14/issues/125#issue-297201412
Another place where this has come up in the wild, but where the fix ended up being different, was
try { ... } catch (ExceptionType ex) {
throw ex;
}
where the appropriate fix in that case was to replace `throw ex;` with `throw;`, and incidentally to catch by reference instead of by value. (But one could contrive a scenario where the slicing was intentional, in which case throw-by-move would have been the appropriate fix after all.)
Another example (intentional slicing to a base class) is dissected in https://github.com/accuBayArea/Slides/blob/master/slides/2018-03-07.pdf
**-Wreturn-std-move-in-c++11**
This diagnostic is enabled only by the exact spelling `-Wreturn-std-move-in-c++11`.
Diagnose cases of "return x;" or "throw x;" which in this version of Clang *do* produce moves, but which prior to Clang 3.9 / GCC 5.1 produced copies instead. This is useful in codebases which care about portability to those older compilers.
The name "-in-c++11" is not technically correct; what caused the version-to-version change in behavior here was actually CWG 1579, not C++14. I think it's likely that codebases that need portability to GCC 4.9-and-earlier may understand "C++11" as a colloquialism for "older compilers." The wording of this diagnostic is based on feedback from @rsmith.
**Discussion**
Notice that this patch is kind of a negative-space version of Richard Trieu's `-Wpessimizing-move`. That diagnostic warns about cases of `return std::move(x)` that should be `return x` for speed. These diagnostics warn about cases of `return x` that should be `return std::move(x)` for speed. (The two diagnostics' bailiwicks do not overlap: we don't have to worry about a `return` statement flipping between the two states indefinitely.)
I propose to write a paper for San Diego that would relax the implicit-move rules so that in C++2a the user //would// see the moves they expect, and the diagnostic could be re-worded in a later version of Clang to suggest explicit `std::move` only "in C++17 and earlier." But in the meantime (and/or forever if that proposal is not well received), this diagnostic will be useful to detect accidental copy operations.
Reviewers: rtrieu, rsmith
Reviewed By: rsmith
Subscribers: lebedev.ri, Rakete1111, rsmith, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D43322
Patch by Arthur O'Dwyer.
llvm-svn: 329914
Found via codespell -q 3 -I ../clang-whitelist.txt
Where whitelist consists of:
archtype
cas
classs
checkk
compres
definit
frome
iff
inteval
ith
lod
methode
nd
optin
ot
pres
statics
te
thru
Patch by luzpaz! (This is a subset of D44188 that applies cleanly with a few
files that have dubious fixes reverted.)
Differential revision: https://reviews.llvm.org/D44188
llvm-svn: 329399
This commit generalizes NRVO to cover C structs (both trivial and
non-trivial structs).
rdar://problem/33599681
Differential Revision: https://reviews.llvm.org/D44968
llvm-svn: 328809
Use an enum parameter instead of a bool for more control on how the copy elision
functions work. Extract the move initialization code from the move or copy
initialization block.
Patch by: Arthur O'Dwyer
Differential Revision: https://reviews.llvm.org/D43898
llvm-svn: 327598
This relands r326965.
There was a null dereference in typo correction that was triggered in
Sema/diagnose_if.c. We are not always in a function scope when doing
typo correction. The fix is to add a null check.
LLVM's optimizer made it hard to find this bug. I wrote it up in a
not-very-well-editted blog post here:
http://qinsb.blogspot.com/2018/03/ub-will-delete-your-null-checks.html
llvm-svn: 327334
This reverts r326965. It seems to have caused repeating test failures in
clang/test/Sema/diagnose_if.c on some buildbots.
I cannot reproduce the problem, and it's not immediately obvious what
the problem is, so let's revert to green.
llvm-svn: 326974
Summary:
Before this patch, Sema pre-allocated a FunctionScopeInfo and kept it in
the first, always present element of the FunctionScopes stack. This
meant that Sema::getCurFunction would return a pointer to this
pre-allocated object when parsing code outside a function body. This is
pretty much always a bug, so this patch moves the pre-allocated object
into a separate unique_ptr. This should make bugs like PR36536 a lot
more obvious.
As you can see from this patch, there were a number of places that
unconditionally assumed they were always called inside a function.
However, there are also many places that null checked the result of
getCurFunction(), so I think this is a reasonable direction.
Reviewers: rsmith
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D44039
llvm-svn: 326965
Summary:
This provides no measurable build speedup, but it reinstates an
optimization from r112038 that was lost in r179618. It requires moving
CapturedScopeInfo::Capture out to clang::sema, which might be too
general since we have plenty of other Capture records in BlockDecl and
other AST nodes.
Reviewers: rjmccall
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D44221
llvm-svn: 326957
We could in principle support such pack expansion, using techniques similar to
what we do for pack expansion of lambdas, but it's not clear it's worthwhile.
For now at least, cleanly reject these cases rather than crashing.
llvm-svn: 324160
Previously, we would:
* compute the type of the conversion function and static invoker as a
side-effect of template argument deduction for a conversion
* re-compute the type as part of deduced return type deduction when building
the conversion function itself
Neither of these turns out to be quite correct. There are other ways to reach a
declaration of the conversion function than in a conversion (such as an
explicit call or friend declaration), and performing auto deduction causes the
function type to be rebuilt in the context of the lambda closure type (which is
different from the context in which it originally appeared, resulting in
spurious substitution failures for constructs that are valid in one context but
not the other, such as the use of an enclosing class's "this" pointer).
This patch switches us to use a different strategy: as before, we use the
declared type of the operator() to form the type of the conversion function and
invoker, but we now populate that type as part of return type deduction for the
conversion function. And the invoker is now treated as simply being an
implementation detail of building the conversion function, and isn't given
special treatment by template argument deduction for the conversion function
any more.
llvm-svn: 321683
Adding the new enumerator forced a bunch more changes into this patch than I
would have liked. The -Wtautological-compare warning was extended to properly
check the new comparison operator, clang-format needed updating because it uses
precedence levels as weights for determining where to break lines (and several
operators increased their precedence levels with this change), thread-safety
analysis needed changes to build its own IL properly for the new operator.
All "real" semantic checking for this operator has been deferred to a future
patch. For now, we use the relational comparison rules and arbitrarily give
the builtin form of the operator a return type of 'void'.
llvm-svn: 320707
This caused warnings also when the if or else comes from macros. There was an
attempt to fix this in r318556, but that introduced new problems and was
reverted. Reverting this too until the whole issue is sorted.
> This looks like it was just an oversight.
>
> Fixes http://llvm.org/pr35319
>
> git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@318456 91177308-0d34-0410-b5e6-96231b3b80d8
llvm-svn: 318667
It seems this somehow made -Wempty-body fire in some macro cases where
it didn't before, e.g.
../../third_party/ffmpeg/libavcodec/bitstream.c(169,5): error: if statement has empty body [-Werror,-Wempty-body]
ff_dlog(NULL, "new table index=%d size=%d\n", table_index, table_size);
^
../../third_party/ffmpeg\libavutil/internal.h(276,80): note: expanded from macro 'ff_dlog'
# define ff_dlog(ctx, ...) do { if (0) av_log(ctx, AV_LOG_DEBUG, __VA_ARGS__); } while (0)
^
../../third_party/ffmpeg/libavcodec/bitstream.c(169,5): note: put the
semicolon on a separate line to silence this warning
Reverting until this can be figured out.
> Do not show it when `if` or `else` come from macros.
> E.g.,
>
> #define USED(A) if (A); else
> #define SOME_IF(A) if (A)
>
> void test() {
> // No warnings are shown in those cases now.
> USED(0);
> SOME_IF(0);
> }
>
> Patch by Ilya Biryukov!
>
> Differential Revision: https://reviews.llvm.org/D40185
llvm-svn: 318665
Do not show it when `if` or `else` come from macros.
E.g.,
#define USED(A) if (A); else
#define SOME_IF(A) if (A)
void test() {
// No warnings are shown in those cases now.
USED(0);
SOME_IF(0);
}
Patch by Ilya Biryukov!
Differential Revision: https://reviews.llvm.org/D40185
llvm-svn: 318556
Treat typedef enum as named enums instead of anonymous enums. Anonymous enums
are ignored by the warning, so previously, typedef enums were ignored as well.
llvm-svn: 312842
Summary:
Currently we build the co_await expressions on the wrong implicit statements of the implicit ranged for; Specifically we build the co_await expression wrapping the range declaration, but it should wrap the begin expression.
This patch fixes co_await on range for.
Reviewers: rsmith, GorNishanov
Reviewed By: GorNishanov
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D34021
llvm-svn: 305363
Summary:
If the first parameter of the function is the ImplicitParamDecl, codegen
automatically marks it as an implicit argument with `this` or `self`
pointer. Added internal kind of the ImplicitParamDecl to separate
'this', 'self', 'vtt' and other implicit parameters from other kind of
parameters.
Reviewers: rjmccall, aaron.ballman
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D33735
llvm-svn: 305075
The warning for unchanged loop variables outputted a diagnostic that was
dependent on iteration order from a pointer set, which is not always
deterministic. Switch to a set vector, which allows fast querying and
preserves ordering.
Also make other minor changes in this area.
Use more range-based for-loops.
Remove limitation on SourceRanges that no logner exists.
llvm-svn: 304519
https://bugs.llvm.org/show_bug.cgi?id=32933
Turns out clang wasn't really handling vla's (*) in C++11's for-range entirely correctly.
For e.g. This would lead to generation of buggy IR:
void foo(int b) {
int vla[b];
b = -1; // This store would affect the '__end = vla + b'
for (int &c : vla)
c = 0;
}
Additionally, code-gen would get confused when VLA's were reference-captured by lambdas, and then used in a for-range, which would result in an attempt to generate IR for '__end = vla + b' within the lambda's body - without any capture of 'b' - hence the assertion.
This patch modifies clang, so that for VLA's it translates the end pointer approximately into:
__end = __begin + sizeof(vla)/sizeof(vla->getElementType())
As opposed to the __end = __begin + b;
I considered passing a magic value into codegen - or having codegen special case the '__end' variable when it referred to a variably-modified type, but I decided against that approach, because it smelled like I would be increasing a complicated form of coupling, that I think would be even harder to maintain than the above approach (which can easily be optimized (-O1) to refer to the run-time bound that was calculated upon array's creation or copied into the lambda's closure object).
(*) why oh why gcc would you enable this by default?! ;)
llvm-svn: 303026
- also replace direct equality checks against the ConstantEvaluated enumerator with isConstantEvaluted(), in anticipation of adding finer granularity to the various ConstantEvaluated contexts and reinstating certain restrictions on where lambda expressions can occur in C++17.
- update the clang tablegen backend that uses these Enumerators, and add the relevant scope where needed.
llvm-svn: 299316
for unused values.
This fixes a regression caused by r298676, where constructor calls to
classes with non-trivial dtor were marked as unused if the first
argument is an initializer list. This is inconsistent (as the test
shows) and also warns on a reasonbly common code pattern where people
just call constructors to create and immediately destroy an object.
llvm-svn: 298853
This commit adds support for a new attribute that will be used to
distinguish between extensible and inextensible enums. There are three
main purposes of this attribute:
1. Give better control over when enum-related warnings are issued.
For example, in the code below, clang will not issue a -Wassign-enum
warning if the enum is marked "open":
enum __attribute__((enum_extensibility(closed))) EnumClosed {
B0 = 1, B1 = 10
};
enum __attribute__((enum_extensibility(open))) EnumOpen {
C0 = 1, C1 = 10
};
enum EnumClosed ec = 100; // warning issued
enum EnumOpen eo = 100; // no warning
2. Enable code-completion and debugging tools to offer better
suggestions.
3. Make it easier for swift's clang importer to determine which swift
type an enum should be mapped to.
For more details, see the discussion I started on cfe-dev:
http://lists.llvm.org/pipermail/cfe-dev/2017-February/052748.html
rdar://problem/12764379
rdar://problem/23145650
Differential Revision: https://reviews.llvm.org/D30766
llvm-svn: 298332
instantiation.
In preparation for converting the template stack to a more general context
stack (so we can include context notes for other kinds of context).
llvm-svn: 295686
Richard Smith