--- /dev/null
+//===--- UseDefaultNoneCheck.cpp - clang-tidy -----------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "UseDefaultNoneCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/OpenMPClause.h"
+#include "clang/AST/Stmt.h"
+#include "clang/AST/StmtOpenMP.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/ASTMatchers/ASTMatchers.h"
+#include "clang/ASTMatchers/ASTMatchersMacros.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+namespace openmp {
+
+void UseDefaultNoneCheck::registerMatchers(MatchFinder *Finder) {
+ // Don't register the check if OpenMP is not enabled; the OpenMP pragmas are
+ // completely ignored then, so no OpenMP entires will be present in the AST.
+ if (!getLangOpts().OpenMP)
+ return;
+
+ Finder->addMatcher(
+ ompExecutableDirective(
+ allOf(isAllowedToContainClauseKind(OMPC_default),
+ anyOf(unless(hasAnyClause(ompDefaultClause())),
+ hasAnyClause(ompDefaultClause(unless(isNoneKind()))
+ .bind("clause")))))
+ .bind("directive"),
+ this);
+}
+
+void UseDefaultNoneCheck::check(const MatchFinder::MatchResult &Result) {
+ const auto *Directive =
+ Result.Nodes.getNodeAs<OMPExecutableDirective>("directive");
+ assert(Directive != nullptr && "Expected to match some directive.");
+
+ if (const auto *Clause = Result.Nodes.getNodeAs<OMPDefaultClause>("clause")) {
+ diag(Directive->getBeginLoc(),
+ "OpenMP directive '%0' specifies 'default(%1)' clause, consider using "
+ "'default(none)' clause instead")
+ << getOpenMPDirectiveName(Directive->getDirectiveKind())
+ << getOpenMPSimpleClauseTypeName(Clause->getClauseKind(),
+ Clause->getDefaultKind());
+ diag(Clause->getBeginLoc(), "existing 'default' clause specified here",
+ DiagnosticIDs::Note);
+ return;
+ }
+
+ diag(Directive->getBeginLoc(),
+ "OpenMP directive '%0' does not specify 'default' clause, consider "
+ "specifying 'default(none)' clause")
+ << getOpenMPDirectiveName(Directive->getDirectiveKind());
+}
+
+} // namespace openmp
+} // namespace tidy
+} // namespace clang
--- /dev/null
+//===--- UseDefaultNoneCheck.h - clang-tidy ---------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_OPENMP_USEDEFAULTNONECHECK_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_OPENMP_USEDEFAULTNONECHECK_H
+
+#include "../ClangTidy.h"
+
+namespace clang {
+namespace tidy {
+namespace openmp {
+
+/// Finds OpenMP directives that are allowed to contain a ``default`` clause,
+/// but either don't specify it or the clause is specified but with the kind
+/// other than ``none``, and suggests to use the ``default(none)`` clause.
+///
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/openmp-use-default-none.html
+class UseDefaultNoneCheck : public ClangTidyCheck {
+public:
+ UseDefaultNoneCheck(StringRef Name, ClangTidyContext *Context)
+ : ClangTidyCheck(Name, Context) {}
+ void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+ void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+};
+
+} // namespace openmp
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_OPENMP_USEDEFAULTNONECHECK_H
--- /dev/null
+.. title:: clang-tidy - openmp-use-default-none
+
+openmp-use-default-none
+=======================
+
+Finds OpenMP directives that are allowed to contain a ``default`` clause,
+but either don't specify it or the clause is specified but with the kind
+other than ``none``, and suggests to use the ``default(none)`` clause.
+
+Using ``default(none)`` clause forces developers to explicitly specify data
+sharing attributes for the variables referenced in the construct,
+thus making it obvious which variables are referenced, and what is their
+data sharing attribute, thus increasing readability and possibly making errors
+easier to spot.
+
+Example
+-------
+
+.. code-block:: c++
+
+ // ``for`` directive can not have ``default`` clause, no diagnostics.
+ void n0(const int a) {
+ #pragma omp for
+ for (int b = 0; b < a; b++)
+ ;
+ }
+
+ // ``parallel`` directive.
+
+ // ``parallel`` directive can have ``default`` clause, but said clause is not
+ // specified, diagnosed.
+ void p0_0() {
+ #pragma omp parallel
+ ;
+ // WARNING: OpenMP directive ``parallel`` does not specify ``default``
+ // clause. Consider specifying ``default(none)`` clause.
+ }
+
+ // ``parallel`` directive can have ``default`` clause, and said clause is
+ // specified, with ``none`` kind, all good.
+ void p0_1() {
+ #pragma omp parallel default(none)
+ ;
+ }
+
+ // ``parallel`` directive can have ``default`` clause, and said clause is
+ // specified, but with ``shared`` kind, which is not ``none``, diagnose.
+ void p0_2() {
+ #pragma omp parallel default(shared)
+ ;
+ // WARNING: OpenMP directive ``parallel`` specifies ``default(shared)``
+ // clause. Consider using ``default(none)`` clause instead.
+ }
--- /dev/null
+// RUN: %check_clang_tidy %s openmp-use-default-none %t -- -- -x c++ -fopenmp=libomp -fopenmp-version=40
+// RUN: %check_clang_tidy %s openmp-use-default-none %t -- -- -x c -fopenmp=libomp -fopenmp-version=40
+
+//----------------------------------------------------------------------------//
+// Null cases.
+//----------------------------------------------------------------------------//
+
+// 'for' directive can not have 'default' clause, no diagnostics.
+void n0(const int a) {
+#pragma omp for
+ for (int b = 0; b < a; b++)
+ ;
+}
+
+//----------------------------------------------------------------------------//
+// Single-directive positive cases.
+//----------------------------------------------------------------------------//
+
+// 'parallel' directive.
+
+// 'parallel' directive can have 'default' clause, but said clause is not
+// specified, diagnosed.
+void p0_0() {
+#pragma omp parallel
+ ;
+ // CHECK-NOTES: :[[@LINE-2]]:9: warning: OpenMP directive 'parallel' does not specify 'default' clause, consider specifying 'default(none)' clause
+}
+
+// 'parallel' directive can have 'default' clause, and said clause specified,
+// with 'none' kind, all good.
+void p0_1() {
+#pragma omp parallel default(none)
+ ;
+}
+
+// 'parallel' directive can have 'default' clause, and said clause specified,
+// but with 'shared' kind, which is not 'none', diagnose.
+void p0_2() {
+#pragma omp parallel default(shared)
+ ;
+ // CHECK-NOTES: :[[@LINE-2]]:9: warning: OpenMP directive 'parallel' specifies 'default(shared)' clause, consider using 'default(none)' clause instead
+ // CHECK-NOTES: :[[@LINE-3]]:22: note: existing 'default' clause specified here
+}
+
+// 'task' directive.
+
+// 'task' directive can have 'default' clause, but said clause is not
+// specified, diagnosed.
+void p1_0() {
+#pragma omp task
+ ;
+ // CHECK-NOTES: :[[@LINE-2]]:9: warning: OpenMP directive 'task' does not specify 'default' clause, consider specifying 'default(none)' clause
+}
+
+// 'task' directive can have 'default' clause, and said clause specified,
+// with 'none' kind, all good.
+void p1_1() {
+#pragma omp task default(none)
+ ;
+}
+
+// 'task' directive can have 'default' clause, and said clause specified,
+// but with 'shared' kind, which is not 'none', diagnose.
+void p1_2() {
+#pragma omp task default(shared)
+ ;
+ // CHECK-NOTES: :[[@LINE-2]]:9: warning: OpenMP directive 'task' specifies 'default(shared)' clause, consider using 'default(none)' clause instead
+ // CHECK-NOTES: :[[@LINE-3]]:18: note: existing 'default' clause specified here
+}
+
+// 'teams' directive. (has to be inside of 'target' directive)
+
+// 'teams' directive can have 'default' clause, but said clause is not
+// specified, diagnosed.
+void p2_0() {
+#pragma omp target
+#pragma omp teams
+ ;
+ // CHECK-NOTES: :[[@LINE-2]]:9: warning: OpenMP directive 'teams' does not specify 'default' clause, consider specifying 'default(none)' clause
+}
+
+// 'teams' directive can have 'default' clause, and said clause specified,
+// with 'none' kind, all good.
+void p2_1() {
+#pragma omp target
+#pragma omp teams default(none)
+ ;
+}
+
+// 'teams' directive can have 'default' clause, and said clause specified,
+// but with 'shared' kind, which is not 'none', diagnose.
+void p2_2() {
+#pragma omp target
+#pragma omp teams default(shared)
+ ;
+ // CHECK-NOTES: :[[@LINE-2]]:9: warning: OpenMP directive 'teams' specifies 'default(shared)' clause, consider using 'default(none)' clause instead
+ // CHECK-NOTES: :[[@LINE-3]]:19: note: existing 'default' clause specified here
+}
+
+// 'taskloop' directive.
+
+// 'taskloop' directive can have 'default' clause, but said clause is not
+// specified, diagnosed.
+void p3_0(const int a) {
+#pragma omp taskloop
+ for (int b = 0; b < a; b++)
+ ;
+ // CHECK-NOTES: :[[@LINE-3]]:9: warning: OpenMP directive 'taskloop' does not specify 'default' clause, consider specifying 'default(none)' clause
+}
+
+// 'taskloop' directive can have 'default' clause, and said clause specified,
+// with 'none' kind, all good.
+void p3_1(const int a) {
+#pragma omp taskloop default(none) shared(a)
+ for (int b = 0; b < a; b++)
+ ;
+}
+
+// 'taskloop' directive can have 'default' clause, and said clause specified,
+// but with 'shared' kind, which is not 'none', diagnose.
+void p3_2(const int a) {
+#pragma omp taskloop default(shared)
+ for (int b = 0; b < a; b++)
+ ;
+ // CHECK-NOTES: :[[@LINE-3]]:9: warning: OpenMP directive 'taskloop' specifies 'default(shared)' clause, consider using 'default(none)' clause instead
+ // CHECK-NOTES: :[[@LINE-4]]:22: note: existing 'default' clause specified here
+}
+
+//----------------------------------------------------------------------------//
+// Combined directives.
+// Let's not test every single possible permutation/combination of directives,
+// but just *one* combined directive. The rest will be the same.
+//----------------------------------------------------------------------------//
+
+// 'parallel' directive can have 'default' clause, but said clause is not
+// specified, diagnosed.
+void p4_0(const int a) {
+#pragma omp parallel for
+ for (int b = 0; b < a; b++)
+ ;
+ // CHECK-NOTES: :[[@LINE-3]]:9: warning: OpenMP directive 'parallel for' does not specify 'default' clause, consider specifying 'default(none)' clause
+}
+
+// 'parallel' directive can have 'default' clause, and said clause specified,
+// with 'none' kind, all good.
+void p4_1(const int a) {
+#pragma omp parallel for default(none) shared(a)
+ for (int b = 0; b < a; b++)
+ ;
+}
+
+// 'parallel' directive can have 'default' clause, and said clause specified,
+// but with 'shared' kind, which is not 'none', diagnose.
+void p4_2(const int a) {
+#pragma omp parallel for default(shared)
+ for (int b = 0; b < a; b++)
+ ;
+ // CHECK-NOTES: :[[@LINE-3]]:9: warning: OpenMP directive 'parallel for' specifies 'default(shared)' clause, consider using 'default(none)' clause instead
+ // CHECK-NOTES: :[[@LINE-4]]:26: note: existing 'default' clause specified here
+}