The various CorrectionCandidateCallbacks are currently heap-allocated
unconditionally. This was needed because of delayed typo correction.
However these allocations represent currently 15.4% of all allocations
(number of allocations) when parsing all of Boost (!), mostly because
of ParseCastExpression, ParseStatementOrDeclarationAfterAttrtibutes
and isCXXDeclarationSpecifier. Note that all of these callback objects
are small. Let's not do this.
Instead initially allocate the callback on the stack, and only do a
heap allocation if we are going to do some typo correction. Do this by:
1. Adding a clone function to each callback, which will do a polymorphic
clone of the callback. This clone function is required to be implemented
by every callback (of which there is a fair amount). Make sure this is
the case by making it pure virtual.
2. Use this clone function when we are going to try to correct a typo.
This additionally cut the time of -fsyntax-only on all of Boost by 0.5%
(not that much, but still something). No functional changes intended.
Differential Revision: https://reviews.llvm.org/D58827
Reviewed By: rnk
llvm-svn: 356925
dynamic_allocators.
According to the OpenMP 5.0, 2.11.3 allocate Directive, Restrictions,
allocate directives that appear in a target region must specify an
allocator clause unless a requires directive with the dynamic_allocators
clause is present in the same compilation unit. Patch adds a check for a
presence of the requires directive with the dynamic_allocators clause.
llvm-svn: 356758
clause in target region.
According to the OpenMP 5.0, 2.11.3 allocate Directive, Restrictions,
allocate directives that appear in a target region must specify an
allocator clause unless a requires directive with the dynamic_allocators
clause is present in the same compilation unit.
llvm-svn: 356752
Previously implemented check required the reevaluation of the already
evaluated predefined allocator kind for the global variables. Patch
simplifies this evaluation and removes extra code.
llvm-svn: 356699
allocators.
It is better to deduce omp_allocator_handle_t type from the predefined
allocators, because omp.h header might not define it explicitly. Plus,
it allows to identify the predefined allocators correctly when trying to
build the allcoator for the global variables.
llvm-svn: 356607
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
If the allocator was specified for the variable and next one is found
with the different allocator, the warning is emitted, and the allocator
is ignored.
llvm-svn: 356513
According to OpenMP, 2.11.3 allocate Directive, Restrictions, C / C++,
if a list item has a static storage type, the allocator expression in
the allocator clause must be a constant expression that evaluates to
one of the predefined memory allocator values. Added check for this
restriction.
llvm-svn: 356496
Summary:
This patch refactors several instances of cast<> used in if
conditionals. Since cast<> asserts on failure, the else branch can
never be taken.
In some cases, the fix is to replace cast<> with dyn_cast<>. While
others required the removal of the conditional and some minor
refactoring.
A discussion can be seen here: http://lists.llvm.org/pipermail/cfe-commits/Week-of-Mon-20190318/265044.html
Differential Revision: https://reviews.llvm.org/D59529
llvm-svn: 356441
If the doacross lop construct is used and the loop counter is declare
outside of the loop, the compiler might crash trying to get the address
of the loop counter. Patch fixes this problem.
llvm-svn: 356198
If the declare target link global is used in the target region
indirectly (used in the inner parallel, teams, etc. regions), we may
miss this variable and it leads to incorrect codegen.
llvm-svn: 355858
This patch implements the parsing and sema support for the OpenMP
'from'-clause with potential user-defined mappers attached.
User-defined mappers are a new feature in OpenMP 5.0. A 'from'-clause
can have an explicit or implicit associated mapper, which instructs the
compiler to generate and use customized mapping functions. An example is
shown below:
struct S { int len; int *d; };
#pragma omp declare mapper(id: struct S s) map(s, s.d[0:s.len])
struct S ss;
#pragma omp target update from(mapper(id): ss) // use the mapper with name 'id' to map ss from device
Contributed-by: Lingda Li <lildmh@gmail.com>
Differential Revision: https://reviews.llvm.org/D58638
llvm-svn: 354817
This patch implements the parsing and sema support for OpenMP to clause
with potential user-defined mappers attached. User defined mapper is a
new feature in OpenMP 5.0. A to/from clause can have an explicit or
implicit associated mapper, which instructs the compiler to generate and
use customized mapping functions. An example is shown below:
struct S { int len; int *d; };
#pragma omp declare mapper(id: struct S s) map(s, s.d[0:s.len])
struct S ss;
#pragma omp target update to(mapper(id): ss) // use the mapper with name 'id' to map ss to device
Contributed-by: <lildmh@gmail.com>
Differential Revision: https://reviews.llvm.org/D58523
llvm-svn: 354698
This patch implements the parsing and sema support for OpenMP map
clauses with potential user-defined mapper attached. User defined mapper
is a new feature in OpenMP 5.0. A map clause can have an explicit or
implicit associated mapper, which instructs the compiler to generate
extra data mapping. An example is shown below:
struct S { int len; int *d; };
#pragma omp declare mapper(id: struct S s) map(s, s.d[0:s.len])
struct S ss;
#pragma omp target map(mapper(id) tofrom: ss) // use the mapper with name 'id' to map ss
Contributed-by: Lingda Li <lildmh@gmail.com>
Differential Revision: https://reviews.llvm.org/D58074
llvm-svn: 354347
Fixed diagnostic emission for the exceptions support in case of the
compilation of OpenMP code for the devices. From now on, it uses delayed
diagnostics mechanism, previously used for CUDA only. It allow to
diagnose not allowed used of exceptions only in functions that are going
to be codegen'ed.
llvm-svn: 353542
It is important to delay the emission of the diagnostic messages for the
functions unless it is proved that the function is going to be used on
the device side. It is required to support compilation with some of the
target-specific system headers.
llvm-svn: 353540
The fix is to issue error messages if there are more than one
teams construct inside a target constructs.
#pragma omp target
{
#pragma omp teams
{ ... }
#pragma omp teams
{ ... }
}
llvm-svn: 353186
edge cases.
Currently, EmitCall emits a call instruction with a function type
derived from the pointee-type of the callee. This *should* be the same
as the type created from the CallInfo parameter, but in some cases an
incorrect CallInfo was being passed.
All of these fixes were discovered by the addition of the assert in
EmitCall which verifies that the passed-in CallInfo matches the
Callee's function type.
As far as I know, these issues caused no bugs at the moment, as the
correct types were ultimately being emitted. But, some would become
problematic when pointee types are removed.
List of fixes:
* arrangeCXXConstructorCall was passing an incorrect value for the
number of Required args, when calling an inheriting constructor
where the inherited constructor is variadic. (The inheriting
constructor doesn't actually get passed any of the user's args, but
the code was calculating it as if it did).
* arrangeFreeFunctionLikeCall was not including the count of the
pass_object_size arguments in the count of required args.
* OpenCL uses other address spaces for the "this" pointer. However,
commonEmitCXXMemberOrOperatorCall was not annotating the address
space on the "this" argument of the call.
* Destructor calls were being created with EmitCXXMemberOrOperatorCall
instead of EmitCXXDestructorCall in a few places. This was a problem
because the calling convention sometimes has destructors returning
"this" rather than void, and the latter function knows about that,
and sets up the types properly (through calling
arrangeCXXStructorDeclaration), while the former does not.
* generateObjCGetterBody: the 'objc_getProperty' function returns type
'id', but was being called as if it returned the particular
property's type. (That is of course the *dynamic* return type, and
there's a downcast immediately after.)
* OpenMP user-defined reduction functions (#pragma omp declare
reduction) can be called with a subclass of the declared type. In
such case, the call was being setup as if the function had been
actually declared to take the subtype, rather than the base type.
Differential Revision: https://reviews.llvm.org/D57664
llvm-svn: 353181
Further reviews (D57594, D57615) have revealed that this was not reviewed,
and that the differential's description was not read during the review,
thus rendering this commit invalid.
This reverts commit r352882.
llvm-svn: 352933
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
Summary:
I'm working on a clang-tidy check, much like existing [[ http://clang.llvm.org/extra/clang-tidy/checks/bugprone-exception-escape.html | bugprone-exception-escape ]],
to detect when an exception might escape out of an OpenMP construct it isn't supposed to escape from.
For that i will be using the `nothrow` bit of `CapturedDecl`s.
While that bit is already correctly set for some constructs, e.g. `#pragma omp parallel`: https://godbolt.org/z/2La7pv
it isn't set for the `#pragma omp sections`, or `#pragma omp section`: https://godbolt.org/z/qZ-EbP
If i'm reading [[ https://www.openmp.org/wp-content/uploads/OpenMP-API-Specification-5.0.pdf | `OpenMP Application Programming Interface Version 5.0 November 2018` ]] correctly,
they should be, as per `2.8.1 sections Construct`, starting with page 86:
* The sections construct is a non-iterative worksharing construct that contains a set of **structured blocks**
that are to be distributed among and executed by the threads in a team. Each **structured block** is executed
once by one of the threads in the team in the context of its implicit task.
* The syntax of the sections construct is as follows:
#pragma omp sections [clause[ [,] clause] ... ] new-line
{
[#pragma omp section new-line]
**structured-block**
...
* Description
Each **structured block** in the sections construct is preceded by a section directive except
possibly **the first block**, for which a preceding section directive is optional.
* Restrictions
• The code enclosed in a sections construct must be a **structured block**.
* A throw executed inside a sections region must cause execution to resume within the same
section of the sections region, and the same thread that threw the exception must catch it.
Reviewers: ABataev, #openmp
Reviewed By: ABataev
Subscribers: guansong, openmp-commits, cfe-commits
Tags: #clang, #openmp
Differential Revision: https://reviews.llvm.org/D57585
llvm-svn: 352882
We don't need to use the predetermined data-sharing attributes for the
loop counters if the user explicitly specified correct data-sharing
attributes for such variables.
llvm-svn: 352543
According to the report, better to keep the original strict compare
operation as the loop condition with unsigned loop counters to make the
loop countable. This allows further loop transformations.
llvm-svn: 352526
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
Summary: Change the strategy for computing loop index variables after collapsing a loop nest via the collapse clause by replacing the expensive remainder operation with multiplications and additions.
Reviewers: ABataev, caomhin
Reviewed By: ABataev
Subscribers: guansong, arphaman, cfe-commits
Differential Revision: https://reviews.llvm.org/D56413
llvm-svn: 350759
Summary: Introduce a compiler flag for cases when the user knows that the collapsed loop counter can be safely represented using at most 32 bits. This will prevent the emission of expensive mathematical operations (such as the div operation) on the iteration variable using 64 bits where 32 bit operations are sufficient.
Reviewers: ABataev, caomhin
Reviewed By: ABataev
Subscribers: hfinkel, kkwli0, guansong, cfe-commits
Differential Revision: https://reviews.llvm.org/D55928
llvm-svn: 350758
Summary:
There is a minor issue in how the implicit data-sharings for nested tasks are computed.
For the following example:
```
int x;
#pragma omp task shared(x)
#pragma omp task
x++;
```
We compute an implicit data-sharing of shared for `x` in the second task although I think that it should be firstprivate. Below you can find the part of the OpenMP spec that covers this example:
- // In a task generating construct, if no default clause is present, a variable for which the data-sharing attribute is not determined by the rules above and that in the enclosing context is determined to be shared by all implicit tasks bound to the current team is shared.//
- //In a task generating construct, if no default clause is present, a variable for which the data-sharing attribute is not determined by the rules above is firstprivate.//
Since each implicit-task has its own copy of `x`, we shouldn't apply the first rule.
Reviewers: ABataev
Reviewed By: ABataev
Subscribers: cfe-commits, rogfer01
Tags: #openmp
Differential Revision: https://reviews.llvm.org/D56430
llvm-svn: 350734
As discussed in D56113, this patch refactors the implementation of the
const restriction for linear to reuse a function introduced by D56113.
A side effect is that, if a variable has mutable members, this
diagnostic is now skipped, and the diagnostic for the variable not
being an integer or pointer is reported instead.
Reviewed By: ABataev
Differential Revision: https://reviews.llvm.org/D56299
llvm-svn: 350441
As discussed in D56113, this patch refactors the implementation of the
const restriction for reductions to reuse a function introduced by
D56113. A side effect is that diagnostics sometimes now say
"variable" instead of "list item" when a list item is a variable.
Reviewed By: ABataev
Differential Revision: https://reviews.llvm.org/D56298
llvm-svn: 350440
The following appears in OpenMP 3.1 sec. 2.9.1.1 as a predetermined
data-sharing attribute:
> Variables with const-qualified type having no mutable member are
> shared.
It does not appear in OpenmP 4.0, 4.5, or 5.0. This patch removes the
implementation of that attribute when the requested OpenMP version is
greater than 3.1.
One effect of that removal is that `default(none)` affects const
variables without mutable members.
Also, without this patch, if a const variable without mutable members
was explicitly lastprivate or private, it was an error because it was
predetermined shared. Now, clang instead complains that it's const
without mutable fields, which is a more intelligible diagnostic. That
should be fine for all of the above versions because they all have
something like the following, which is quoted from OpenMP 5.0
sec. 2.19.3:
> A variable that is privatized must not have a const-qualified type
> unless it is of class type with a mutable member. This restriction does
> not apply to the firstprivate clause.
reduction and linear clauses already have separate checks for const
variables. Future patches will merge the implementations.
Reviewed By: ABataev
Differential Revision: https://reviews.llvm.org/D56113
llvm-svn: 350439
Rather than sprinkle calls to DiagnoseUnusedExprResult() around in places where we want diagnostics, we now diagnose unused expression statements and full expressions in a more generic way when acting on the final expression statement. This results in more appropriate diagnostics for [[nodiscard]] where we were previously lacking them, such as when the body of a for loop is not a compound statement.
This patch fixes PR39837.
llvm-svn: 350404
For constants with the predefined data-sharing clauses we may had
troubles with the target combined directives. It may cause compiler
crash in some corner cases.
llvm-svn: 350127
Since CallExpr::setNumArgs has been removed, it is now possible to store the
callee expression and the argument expressions of CallExpr in a trailing array.
This saves one pointer per CallExpr, CXXOperatorCallExpr, CXXMemberCallExpr,
CUDAKernelCallExpr and UserDefinedLiteral.
Given that CallExpr is used as a base of the above classes we cannot use
llvm::TrailingObjects. Instead we store the offset in bytes from the this pointer
to the start of the trailing objects and manually do the casts + arithmetic.
Some notes:
1.) I did not try to fit the number of arguments in the bit-fields of Stmt.
This leaves some space for future additions and avoid the discussion about
whether x bits are sufficient to hold the number of arguments.
2.) It would be perfectly possible to recompute the offset to the trailing
objects before accessing the trailing objects. However the trailing objects
are frequently accessed and benchmarks show that it is slightly faster to
just load the offset from the bit-fields. Additionally, because of 1),
we have plenty of space in the bit-fields of Stmt.
Differential Revision: https://reviews.llvm.org/D55771
Reviewed By: rjmccall
llvm-svn: 349910
Need to mark the loop as started when the initialization statement is
found. It is required to prevent possible incorrect loop iteraton
variable detection during template instantiation and fix the compiler
crash during the codegen.
llvm-svn: 349657
Without this patch, clang doesn't complain that X needs explicit data
sharing attributes in the following:
```
#pragma omp target teams default(none)
{
#pragma omp parallel num_threads(X)
;
}
```
However, clang does produce that complaint after the braces are
removed. With this patch, clang complains in both cases.
Reviewed By: ABataev
Differential Revision: https://reviews.llvm.org/D55861
llvm-svn: 349635
A map clause with the close map-type-modifier is a hint to
prefer that the variables are mapped using a copy into faster
memory.
Patch by Ahsan Saghir (saghir)
Differential Revision: https://reviews.llvm.org/D55719
llvm-svn: 349551
It seems the two failing tests can be simply fixed after r348037
Fix 3 cases in Analysis/builtin-functions.cpp
Delete the bad CodeGen/builtin-constant-p.c for now
llvm-svn: 348053
Kept the "indirect_builtin_constant_p" test case in test/SemaCXX/constant-expression-cxx1y.cpp
while we are investigating why the following snippet fails:
extern char extern_var;
struct { int a; } a = {__builtin_constant_p(extern_var)};
llvm-svn: 348039
This was reverted in r347656 due to me thinking it caused a miscompile of
Chromium. Turns out it was the Chromium code that was broken.
llvm-svn: 347756
