This reverts commit 08ea1ee2db5f9d6460fef1d79d0d1d1a5eb78982.
It broke ./ClangdTests/FindExplicitReferencesTest.All
on the bots, see comments on https://reviews.llvm.org/D69360
This patch is motivated by (and factored out from)
https://reviews.llvm.org/D66121 which is a debug info bugfix. Starting
with DWARF 5 all Objective-C methods are nested inside their
containing type, and that patch implements this for synthesized
Objective-C properties.
1. SemaObjCProperty populates a list of synthesized accessors that may
need to inserted into an ObjCImplDecl.
2. SemaDeclObjC::ActOnEnd inserts forward-declarations for all
accessors for which no override was provided into their
ObjCImplDecl. This patch does *not* synthesize AST function
*bodies*. Moving that code from the static analyzer into Sema may
be a good idea though.
3. Places that expect all methods to have bodies have been updated.
I did not update the static analyzer's inliner for synthesized
properties to point back to the property declaration (see
test/Analysis/Inputs/expected-plists/nullability-notes.m.plist), which
I believed to be more bug than a feature.
Differential Revision: https://reviews.llvm.org/D68108
rdar://problem/53782400
has a constexpr destructor.
For constexpr variables, reject if the variable does not have constant
destruction. In all cases, do not emit runtime calls to the destructor
for variables with constant destruction.
llvm-svn: 373159
non-trivial C union types
This recommits r365985, which was reverted because it broke a few
projects using unions containing non-trivial ObjC pointer fields in
system headers. We now have a patch to fix the problem (see
https://reviews.llvm.org/D65256).
Original commit message:
This patch diagnoses uses of non-trivial C unions and structs/unions
containing non-trivial C unions in the following contexts, which require
default-initialization, destruction, or copying of the union objects,
instead of disallowing fields of non-trivial types in C unions, which is
what we currently do:
- function parameters.
- function returns.
- assignments.
- compound literals.
- block captures except capturing of `__block` variables by non-escaping blocks.
- local and global variable definitions.
- lvalue-to-rvalue conversions of volatile types.
See the discussion in https://reviews.llvm.org/D62988 for more background.
rdar://problem/50679094
Differential Revision: https://reviews.llvm.org/D63753
llvm-svn: 371275
This reverts commit r365985.
Prior to r365985, clang used to mark C union fields that have
non-trivial ObjC ownership qualifiers as unavailable if the union was
declared in a system header. r365985 stopped doing so, which caused the
swift compiler to crash when it tried to import a non-trivial union.
I have a patch that fixes the crash (https://reviews.llvm.org/D65256),
but I'm temporarily reverting the original patch until we can decide on
whether it's taking the right approach.
llvm-svn: 367076
non-trivial C union types
This patch diagnoses uses of non-trivial C unions and structs/unions
containing non-trivial C unions in the following contexts, which require
default-initialization, destruction, or copying of the union objects,
instead of disallowing fields of non-trivial types in C unions, which is
what we currently do:
- function parameters.
- function returns.
- assignments.
- compound literals.
- block captures except capturing of `__block` variables by non-escaping
blocks.
- local and global variable definitions.
- lvalue-to-rvalue conversions of volatile types.
See the discussion in https://reviews.llvm.org/D62988 for more background.
rdar://problem/50679094
Differential Revision: https://reviews.llvm.org/D63753
llvm-svn: 365985
This moves Bitcode/Bitstream*, Bitcode/BitCodes.h to Bitstream/.
This is needed to avoid a circular dependency when using the bitstream
code for parsing optimization remarks.
Since Bitcode uses Core for the IR part:
libLLVMRemarks -> Bitcode -> Core
and Core uses libLLVMRemarks to generate remarks (see
IR/RemarkStreamer.cpp):
Core -> libLLVMRemarks
we need to separate the Bitstream and Bitcode part.
For clang-doc, it seems that it doesn't need the whole bitcode layer, so
I updated the CMake to only use the bitstream part.
Differential Revision: https://reviews.llvm.org/D63899
llvm-svn: 365091
Summary:
this revision adds Lexing, Parsing and Basic Semantic for the consteval specifier as specified by http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/p1073r3.html
with this patch, the consteval specifier is treated as constexpr but can only be applied to function declaration.
Changes:
- add the consteval keyword.
- add parsing of consteval specifier for normal declarations and lambdas expressions.
- add the whether a declaration is constexpr is now represented by and enum everywhere except for variable because they can't be consteval.
- adapt diagnostic about constexpr to print constexpr or consteval depending on the case.
- add tests for basic semantic.
Reviewers: rsmith, martong, shafik
Reviewed By: rsmith
Subscribers: eraman, efriedma, rnkovacs, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D61790
llvm-svn: 363362
This caused Clang to start erroring on the following:
struct S {
template <typename = int> explicit S();
};
struct T : S {};
struct U : T {
U();
};
U::U() {}
$ clang -c /tmp/x.cc
/tmp/x.cc:10:4: error: call to implicitly-deleted default constructor of 'T'
U::U() {}
^
/tmp/x.cc:5:12: note: default constructor of 'T' is implicitly deleted
because base class 'S' has no default constructor
struct T : S {};
^
1 error generated.
See discussion on the cfe-commits email thread.
This also reverts the follow-ups r359966 and r359968.
> this patch adds support for the explicit bool specifier.
>
> Changes:
> - The parsing for the explicit(bool) specifier was added in ParseDecl.cpp.
> - The storage of the explicit specifier was changed. the explicit specifier was stored as a boolean value in the FunctionDeclBitfields and in the DeclSpec class. now it is stored as a PointerIntPair<Expr*, 2> with a flag and a potential expression in CXXConstructorDecl, CXXDeductionGuideDecl, CXXConversionDecl and in the DeclSpec class.
> - Following the AST change, Serialization, ASTMatchers, ASTComparator and ASTPrinter were adapted.
> - Template instantiation was adapted to instantiate the potential expressions of the explicit(bool) specifier When instantiating their associated declaration.
> - The Add*Candidate functions were adapted, they now take a Boolean indicating if the context allowing explicit constructor or conversion function and this boolean is used to remove invalid overloads that required template instantiation to be detected.
> - Test for Semantic and Serialization were added.
>
> This patch is not yet complete. I still need to check that interaction with CTAD and deduction guides is correct. and add more tests for AST operations. But I wanted first feedback.
> Perhaps this patch should be spited in smaller patches, but making each patch testable as a standalone may be tricky.
>
> Patch by Tyker
>
> Differential Revision: https://reviews.llvm.org/D60934
llvm-svn: 360024
this patch adds support for the explicit bool specifier.
Changes:
- The parsing for the explicit(bool) specifier was added in ParseDecl.cpp.
- The storage of the explicit specifier was changed. the explicit specifier was stored as a boolean value in the FunctionDeclBitfields and in the DeclSpec class. now it is stored as a PointerIntPair<Expr*, 2> with a flag and a potential expression in CXXConstructorDecl, CXXDeductionGuideDecl, CXXConversionDecl and in the DeclSpec class.
- Following the AST change, Serialization, ASTMatchers, ASTComparator and ASTPrinter were adapted.
- Template instantiation was adapted to instantiate the potential expressions of the explicit(bool) specifier When instantiating their associated declaration.
- The Add*Candidate functions were adapted, they now take a Boolean indicating if the context allowing explicit constructor or conversion function and this boolean is used to remove invalid overloads that required template instantiation to be detected.
- Test for Semantic and Serialization were added.
This patch is not yet complete. I still need to check that interaction with CTAD and deduction guides is correct. and add more tests for AST operations. But I wanted first feedback.
Perhaps this patch should be spited in smaller patches, but making each patch testable as a standalone may be tricky.
Patch by Tyker
Differential Revision: https://reviews.llvm.org/D60934
llvm-svn: 359949
explicit function specialization with the MemberSpecializationInfo used
everywhere else.
Not NFC: the ad-hoc pattern tracking was not being serialized /
deserialized properly. That's fixed here.
llvm-svn: 359747
Summary:
https://www.openmp.org/wp-content/uploads/OpenMP-API-Specification-5.0.pdf, page 3:
```
structured block
For C/C++, an executable statement, possibly compound, with a single entry at the
top and a single exit at the bottom, or an OpenMP construct.
COMMENT: See Section 2.1 on page 38 for restrictions on structured
blocks.
```
```
2.1 Directive Format
Some executable directives include a structured block. A structured block:
• may contain infinite loops where the point of exit is never reached;
• may halt due to an IEEE exception;
• may contain calls to exit(), _Exit(), quick_exit(), abort() or functions with a
_Noreturn specifier (in C) or a noreturn attribute (in C/C++);
• may be an expression statement, iteration statement, selection statement, or try block, provided
that the corresponding compound statement obtained by enclosing it in { and } would be a
structured block; and
Restrictions
Restrictions to structured blocks are as follows:
• Entry to a structured block must not be the result of a branch.
• The point of exit cannot be a branch out of the structured block.
C / C++
• The point of entry to a structured block must not be a call to setjmp().
• longjmp() and throw() must not violate the entry/exit criteria.
```
Of particular note here is the fact that OpenMP structured blocks are as-if `noexcept`,
in the same sense as with the normal `noexcept` functions in C++.
I.e. if throw happens, and it attempts to travel out of the `noexcept` function
(here: out of the current structured-block), then the program terminates.
Now, one of course can say that since it is explicitly prohibited by the Specification,
then any and all programs that violate this Specification contain undefined behavior,
and are unspecified, and thus no one should care about them. Just don't write broken code /s
But i'm not sure this is a reasonable approach.
I have personally had oss-fuzz issues of this origin - exception thrown inside
of an OpenMP structured-block that is not caught, thus causing program termination.
This issue isn't all that hard to catch, it's not any particularly different from
diagnosing the same situation with the normal `noexcept` function.
Now, clang static analyzer does not presently model exceptions.
But clang-tidy has a simplisic [[ https://clang.llvm.org/extra/clang-tidy/checks/bugprone-exception-escape.html | bugprone-exception-escape ]] check,
and it is even refactored as a `ExceptionAnalyzer` class for reuse.
So it would be trivial to use that analyzer to check for
exceptions escaping out of OpenMP structured blocks. (D59466)
All that sounds too great to be true. Indeed, there is a caveat.
Presently, it's practically impossible to do. To check a OpenMP structured block
you need to somehow 'get' the OpenMP structured block, and you can't because
it's simply not modelled in AST. `CapturedStmt`/`CapturedDecl` is not it's representation.
Now, it is of course possible to write e.g. some AST matcher that would e.g.
match every OpenMP executable directive, and then return the whatever `Stmt` is
the structured block of said executable directive, if any.
But i said //practically//. This isn't practical for the following reasons:
1. This **will** bitrot. That matcher will need to be kept up-to-date,
and refreshed with every new OpenMP spec version.
2. Every single piece of code that would want that knowledge would need to
have such matcher. Well, okay, if it is an AST matcher, it could be shared.
But then you still have `RecursiveASTVisitor` and friends.
`2 > 1`, so now you have code duplication.
So it would be reasonable (and is fully within clang AST spirit) to not
force every single consumer to do that work, but instead store that knowledge
in the correct, and appropriate place - AST, class structure.
Now, there is another hoop we need to get through.
It isn't fully obvious //how// to model this.
The best solution would of course be to simply add a `OMPStructuredBlock` transparent
node. It would be optimal, it would give us two properties:
* Given this `OMPExecutableDirective`, what's it OpenMP structured block?
* It is trivial to check whether the `Stmt*` is a OpenMP structured block (`isa<OMPStructuredBlock>(ptr)`)
But OpenMP structured block isn't **necessarily** the first, direct child of `OMP*Directive`.
(even ignoring the clang's `CapturedStmt`/`CapturedDecl` that were inserted inbetween).
So i'm not sure whether or not we could re-create AST statements after they were already created?
There would be other costs to a new AST node: https://bugs.llvm.org/show_bug.cgi?id=40563#c12
```
1. You will need to break the representation of loops. The body should be replaced by the "structured block" entity.
2. You will need to support serialization/deserialization.
3. You will need to support template instantiation.
4. You will need to support codegen and take this new construct to account in each OpenMP directive.
```
Instead, there **is** an functionally-equivalent, alternative solution, consisting of two parts.
Part 1:
* Add a member function `isStandaloneDirective()` to the `OMPExecutableDirective` class,
that will tell whether this directive is stand-alone or not, as per the spec.
We need it because we can't just check for the existance of associated statements,
see code comment.
* Add a member function `getStructuredBlock()` to the OMPExecutableDirective` class itself,
that assert that this is not a stand-alone directive, and either return the correct loop body
if this is a loop-like directive, or the captured statement.
This way, given an `OMPExecutableDirective`, we can get it's structured block.
Also, since the knowledge is ingrained into the clang OpenMP implementation,
it will not cause any duplication, and //hopefully// won't bitrot.
Great we achieved 1 of 2 properties of `OMPStructuredBlock` approach.
Thus, there is a second part needed:
* How can we check whether a given `Stmt*` is `OMPStructuredBlock`?
Well, we can't really, in general. I can see this workaround:
```
class FunctionASTVisitor : public RecursiveASTVisitor<FunctionASTVisitor> {
using Base = RecursiveASTVisitor<FunctionASTVisitor>;
public:
bool VisitOMPExecDir(OMPExecDir *D) {
OmpStructuredStmts.emplace_back(D.getStructuredStmt());
}
bool VisitSOMETHINGELSE(???) {
if(InOmpStructuredStmt)
HI!
}
bool TraverseStmt(Stmt *Node) {
if (!Node)
return Base::TraverseStmt(Node);
if (OmpStructuredStmts.back() == Node)
++InOmpStructuredStmt;
Base::TraverseStmt(Node);
if (OmpStructuredStmts.back() == Node) {
OmpStructuredStmts.pop_back();
--InOmpStructuredStmt;
}
return true;
}
std::vector<Stmt*> OmpStructuredStmts;
int InOmpStructuredStmt = 0;
};
```
But i really don't see using it in practice.
It's just too intrusive; and again, requires knowledge duplication.
.. but no. The solution lies right on the ground.
Why don't we simply store this `i'm a openmp structured block` in the bitfield of the `Stmt` itself?
This does not appear to have any impact on the memory footprint of the clang AST,
since it's just a single extra bit in the bitfield. At least the static assertions don't fail.
Thus, indeed, we can achieve both of the properties without a new AST node.
We can cheaply set that bit right in sema, at the end of `Sema::ActOnOpenMPExecutableDirective()`,
by just calling the `getStructuredBlock()` that we just added.
Test coverage that demonstrates all this has been added.
This isn't as great with serialization though. Most of it does not use abbrevs,
so we do end up paying the full price (4 bytes?) instead of a single bit.
That price, of course, can be reclaimed by using abbrevs.
In fact, i suspect that //might// not just reclaim these bytes, but pack these PCH significantly.
I'm not seeing a third solution. If there is one, it would be interesting to hear about it.
("just don't write code that would require `isa<OMPStructuredBlock>(ptr)`" is not a solution.)
Fixes [[ https://bugs.llvm.org/show_bug.cgi?id=40563 | PR40563 ]].
Reviewers: ABataev, rjmccall, hfinkel, rsmith, riccibruno, gribozavr
Reviewed By: ABataev, gribozavr
Subscribers: mgorny, aaron.ballman, steveire, guansong, jfb, jdoerfert, cfe-commits
Tags: #clang, #openmp
Differential Revision: https://reviews.llvm.org/D59214
llvm-svn: 356570
initializes a local auto variable or is assigned to a local auto
variable that is declared in the scope that introduced the block
literal.
rdar://problem/13289333
https://reviews.llvm.org/D58514
llvm-svn: 355012
For global variables with unordered initialization that are instantiated
within a module, we previously did not emit the global (or its
initializer) at all unless it was used in the importing translation unit
(and sometimes not even then!), leading to misbehavior and link errors.
We now emit the initializer for an instantiated global variable with
unordered initialization with side-effects in a module into every
translation unit that imports the module. This is unfortunate, but
mostly matches the behavior of a non-modular compilation and seems to be
the best that we can reasonably do.
llvm-svn: 353240
This patch implements parsing and sema for "omp declare mapper"
directive. User defined mapper, i.e., declare mapper directive, is a new
feature in OpenMP 5.0. It is introduced to extend existing map clauses
for the purpose of simplifying the copy of complex data structures
between host and device (i.e., deep copy). An example is shown below:
struct S { int len; int *d; };
#pragma omp declare mapper(struct S s) map(s, s.d[0:s.len]) // Memory region that d points to is also mapped using this mapper.
Contributed-by: Lingda Li <lildmh@gmail.com>
Differential Revision: https://reviews.llvm.org/D56326
llvm-svn: 352906
to reflect the new license.
We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.
Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.
llvm-svn: 351636
This attribute, called "objc_externally_retained", exposes clang's
notion of pseudo-__strong variables in ARC. Pseudo-strong variables
"borrow" their initializer, meaning that they don't retain/release
it, instead assuming that someone else is keeping their value alive.
If a function is annotated with this attribute, implicitly strong
parameters of that function aren't implicitly retained/released in
the function body, and are implicitly const. This is useful to expose
for performance reasons, most functions don't need the extra safety
of the retain/release, so programmers can opt out as needed.
This attribute can also apply to declarations of local variables,
with similar effect.
Differential revision: https://reviews.llvm.org/D55865
llvm-svn: 350422
from those that aren't.
This patch changes the way __block variables that aren't captured by
escaping blocks are handled:
- Since non-escaping blocks on the stack never get copied to the heap
(see https://reviews.llvm.org/D49303), Sema shouldn't error out when
the type of a non-escaping __block variable doesn't have an accessible
copy constructor.
- IRGen doesn't have to use the specialized byref structure (see
https://clang.llvm.org/docs/Block-ABI-Apple.html#id8) for a
non-escaping __block variable anymore. Instead IRGen can emit the
variable as a normal variable and copy the reference to the block
literal. Byref copy/dispose helpers aren't needed either.
This reapplies r343518 after fixing a use-after-free bug in function
Sema::ActOnBlockStmtExpr where the BlockScopeInfo was dereferenced after
it was popped and deleted.
rdar://problem/39352313
Differential Revision: https://reviews.llvm.org/D51564
llvm-svn: 343542
from those that aren't.
This patch changes the way __block variables that aren't captured by
escaping blocks are handled:
- Since non-escaping blocks on the stack never get copied to the heap
(see https://reviews.llvm.org/D49303), Sema shouldn't error out when
the type of a non-escaping __block variable doesn't have an accessible
copy constructor.
- IRGen doesn't have to use the specialized byref structure (see
https://clang.llvm.org/docs/Block-ABI-Apple.html#id8) for a
non-escaping __block variable anymore. Instead IRGen can emit the
variable as a normal variable and copy the reference to the block
literal. Byref copy/dispose helpers aren't needed either.
This reapplies r341754, which was reverted in r341757 because it broke a
couple of bots. r341754 was calling markEscapingByrefs after the call to
PopFunctionScopeInfo, which caused the popped function scope to be
cleared out when the following code was compiled, for example:
$ cat test.m
struct A {
id data[10];
};
void foo() {
__block A v;
^{ (void)v; };
}
This commit calls markEscapingByrefs before calling PopFunctionScopeInfo
to prevent that from happening.
rdar://problem/39352313
Differential Revision: https://reviews.llvm.org/D51564
llvm-svn: 343518
Add support for OMP5.0 requires directive and unified_address clause.
Patches to follow will include support for additional clauses.
Differential Revision: https://reviews.llvm.org/D52359
llvm-svn: 343063
declare reduction.
If the declare reduction construct with the non-dependent type is
defined in the template construct, the compiler might crash on the
template instantition. Reworked the whole instantiation scheme for the
declare reduction constructs to fix this problem correctly.
llvm-svn: 342151
from those that aren't.
This patch changes the way __block variables that aren't captured by
escaping blocks are handled:
- Since non-escaping blocks on the stack never get copied to the heap
(see https://reviews.llvm.org/D49303), Sema shouldn't error out when
the type of a non-escaping __block variable doesn't have an accessible
copy constructor.
- IRGen doesn't have to use the specialized byref structure (see
https://clang.llvm.org/docs/Block-ABI-Apple.html#id8) for a
non-escaping __block variable anymore. Instead IRGen can emit the
variable as a normal variable and copy the reference to the block
literal. Byref copy/dispose helpers aren't needed either.
rdar://problem/39352313
Differential Revision: https://reviews.llvm.org/D51564
llvm-svn: 341754
The compiler may produce unexpected error messages/crashes when declare
target variables were used. Patch fixes problems with the declarations
marked as declare target to or link.
llvm-svn: 339805
Clang generates copy and dispose helper functions for each block literal
on the stack. Often these functions are equivalent for different blocks.
This commit makes changes to merge equivalent copy and dispose helper
functions and reduce code size.
To enable merging equivalent copy/dispose functions, the captured object
infomation is encoded into the helper function name. This allows IRGen
to check whether an equivalent helper function has already been emitted
and reuse the function instead of generating a new helper function
whenever a block is defined. In addition, the helper functions are
marked as linkonce_odr to enable merging helper functions that have the
same name across translation units and marked as unnamed_addr to enable
the linker's deduplication pass to merge functions that have different
names but the same content.
rdar://problem/42640608
Differential Revision: https://reviews.llvm.org/D50152
llvm-svn: 339438
DeclContext has a little less than 8 bytes free due to the alignment
requirements on 64 bits archs. This set of patches moves the
bit-fields from classes deriving from DeclContext into DeclContext.
On 32 bits archs this increases the size of DeclContext by 4 bytes
but this is balanced by an equal or larger reduction in the size
of the classes deriving from it.
On 64 bits archs the size of DeclContext stays the same but
most of the classes deriving from it shrink by 8/16 bytes.
(-print-stats diff here https://reviews.llvm.org/D49728)
When doing an -fsyntax-only on all of Boost this result
in a 3.6% reduction in the size of all Decls and
a 1% reduction in the run time due to the lower cache
miss rate.
For now CXXRecordDecl is not touched but there is
an easy 6 (if I count correctly) bytes gain available there
by moving some bits from DefinitionData into the free
space of DeclContext. This will be the subject of another patch.
This patch sequence also enable the possibility of refactoring
FunctionDecl: To save space some bits from classes deriving from
FunctionDecl were moved to FunctionDecl. This resulted in a
lot of stuff in FunctionDecl which do not belong logically to it.
After this set of patches however it is just a simple matter of
adding a SomethingDeclBitfields in DeclContext and moving the
bits to it from FunctionDecl.
This first patch introduces the anonymous union in DeclContext
and all the *DeclBitfields classes holding the bit-fields, and moves
the bits from TagDecl, EnumDecl and RecordDecl into DeclContext.
This patch is followed by https://reviews.llvm.org/D49732,
https://reviews.llvm.org/D49733 and https://reviews.llvm.org/D49734.
Differential Revision: https://reviews.llvm.org/D49729
Patch By: bricci
llvm-svn: 338630
Summary:
As discussed in [[ https://bugs.llvm.org/show_bug.cgi?id=38166 | PR38166 ]], we need to be able to distinqush whether the cast
we are visiting is actually a cast, or part of an `ExplicitCast`.
There are at least four ways to get there:
1. Introduce a new `CastKind`, and use it instead of `IntegralCast` if we are in `ExplicitCast`.
Would work, but does not scale - what if we will need more of these cast kinds?
2. Introduce a flag in `CastExprBits`, whether this cast is part of `ExplicitCast` or not.
Would work, but it isn't immediately clear where it needs to be set.
2. Fix `ScalarExprEmitter::VisitCastExpr()` to visit these `NoOp` casts.
As pointed out by @rsmith, CodeGenFunction::EmitMaterializeTemporaryExpr calls
skipRValueSubobjectAdjustments, which steps over the CK_NoOp cast`,
which explains why we currently don't visit those.
This is probably impossible, as @efriedma points out, that is intentional as per `[class.temporary]` in the standard
3. And the simplest one, just record which NoOp casts we skip.
It just kinda works as-is afterwards.
But, the approach with a flag is the least intrusive one, and is probably the best one overall.
Reviewers: rsmith, rjmccall, majnemer, efriedma
Reviewed By: rsmith
Subscribers: cfe-commits, aaron.ballman, vsk, llvm-commits, rsmith
Differential Revision: https://reviews.llvm.org/D49508
llvm-svn: 337815
not the corresponding location information) earlier.
We need the type as written in order to properly merge functions with
deduced return types, so we need to load that early. But we don't want
to load the location information early, because that contains
problematic things such as the function parameters.
llvm-svn: 336016
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
