This patch implements Clang support for an original OpenMP extension
we have developed to support OpenACC: the `ompx_hold` map type
modifier. The next patch in this series, D106510, implements OpenMP
runtime support.
Consider the following example:
```
#pragma omp target data map(ompx_hold, tofrom: x) // holds onto mapping of x
{
foo(); // might have map(delete: x)
#pragma omp target map(present, alloc: x) // x is guaranteed to be present
printf("%d\n", x);
}
```
The `ompx_hold` map type modifier above specifies that the `target
data` directive holds onto the mapping for `x` throughout the
associated region regardless of any `target exit data` directives
executed during the call to `foo`. Thus, the presence assertion for
`x` at the enclosed `target` construct cannot fail. (As usual, the
standard OpenMP reference count for `x` must also reach zero before
the data is unmapped.)
Justification for inclusion in Clang and LLVM's OpenMP runtime:
* The `ompx_hold` modifier supports OpenACC functionality (structured
reference count) that cannot be achieved in standard OpenMP, as of
5.1.
* The runtime implementation for `ompx_hold` (next patch) will thus be
used by Flang's OpenACC support.
* The Clang implementation for `ompx_hold` (this patch) as well as the
runtime implementation are required for the Clang OpenACC support
being developed as part of the ECP Clacc project, which translates
OpenACC to OpenMP at the directive AST level. These patches are the
first step in upstreaming OpenACC functionality from Clacc.
* The Clang implementation for `ompx_hold` is also used by the tests
in the runtime implementation. That syntactic support makes the
tests more readable than low-level runtime calls can. Moreover,
upstream Flang and Clang do not yet support OpenACC syntax
sufficiently for writing the tests.
* More generally, the Clang implementation enables a clean separation
of concerns between OpenACC and OpenMP development in LLVM. That
is, LLVM's OpenMP developers can discuss, modify, and debug LLVM's
extended OpenMP implementation and test suite without directly
considering OpenACC's language and execution model, which can be
handled by LLVM's OpenACC developers.
* OpenMP users might find the `ompx_hold` modifier useful, as in the
above example.
See new documentation introduced by this patch in `openmp/docs` for
more detail on the functionality of this extension and its
relationship with OpenACC. For example, it explains how the runtime
must support two reference counts, as specified by OpenACC.
Clang recognizes `ompx_hold` unless `-fno-openmp-extensions`, a new
command-line option introduced by this patch, is specified.
Reviewed By: ABataev, jdoerfert, protze.joachim, grokos
Differential Revision: https://reviews.llvm.org/D106509
This patch implements Clang front end support for the OpenMP TR8
`present` map type modifier. The next patch in this series implements
OpenMP runtime support.
This patch does not attempt to implement TR8 sec. 2.22.7.1 "map
Clause", p. 319, L14-16:
> If a map clause with a present map-type-modifier is present in a map
> clause, then the effect of the clause is ordered before all other
> map clauses that do not have the present modifier.
Compare to L10-11, which Clang does not appear to implement yet:
> For a given construct, the effect of a map clause with the to, from,
> or tofrom map-type is ordered before the effect of a map clause with
> the alloc, release, or delete map-type.
This patch also does not implement the `present` implicit-behavior for
`defaultmap` or the `present` motion-modifier for `target update`.
Reviewed By: ABataev
Differential Revision: https://reviews.llvm.org/D83061
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
Summary:
-ast-print prints omp pragmas with a trailing space. While this
behavior is likely of little concern to most users, surely it's
unintentional, and it's annoying for some source-level work I'm
pursuing. This patch focuses on omp pragmas, but it also fixes
init_seg and loop hint pragmas because they share implementation.
The testing strategy here is to add usually just one '{{$}}' per
relevant -ast-print test file. This seems to achieve good code
coverage. However, this strategy is probably easy to forget as the
tests evolve. That's probably fine as this fix is far from critical.
The main goal of the testing is to aid the initial review.
This patch also adds a fixme for "#pragma unroll", which prints as
"#pragma unroll (enable)", which is invalid syntax.
Reviewers: ABataev
Reviewed By: ABataev
Subscribers: guansong, cfe-commits
Differential Revision: https://reviews.llvm.org/D43204
llvm-svn: 325145
only.
Added support for -fopenmp-simd option that allows compilation of
simd-based constructs without emission of OpenMP runtime calls.
llvm-svn: 321560
Directive name modifiers in 'if' clause are allowed only for OpenMP 4.5
and higher + in OpenMP 4.5 parsing procedure emits error message if ':'
is not found after directive name modifier.
llvm-svn: 290175
Output generated by option -ast-print looks like C/C++ code, and it
really is for plain C. For C++ the produced output was not valid C++
code, but the differences were small. With this change the output
is fixed and can be compiled. Tests are changed so that output produced
by -ast-print is compiled again with the same flags and both outputs are
compared.
Option -ast-print is extensively used in clang tests but it itself
was tested poorly, existing tests only checked that compiler did not
crash. There are unit tests in file DeclPrinterTest.cpp, but they test
only terse output mode.
Differential Revision: https://reviews.llvm.org/D26452
llvm-svn: 286439
Summary:
Adds the following restriction in the OpenMP specifications.
OpenMP [2.10.1, Restrictions, p. 97]
At least one map clause must appear on the directive.
Reviewers: ABataev
Differential Revision: http://reviews.llvm.org/D16341
llvm-svn: 258425
Fixed codegen for extended format of 'if' clauses with special 'directive-name-modifier' + ast-print tests for extended format of 'if' clause.
llvm-svn: 246748
Joel E. Denny