[OpenMP] Prevent nesting of target constructs within target code execution regions.

Summary:
This patch enhances Sema to check for the following restriction:

OpenMP 4.5 [2.17 Nesting of Regions]
If a target, target update, target data, target enter data, or
target exit data construct is encountered during execution of a
target region, the behavior is unspecified.

Reviewers: ABataev

Differential Revision: http://reviews.llvm.org/D16758

llvm-svn: 259464

1 files changed, 6 insertions, 0 deletions

diff --git a/clang/test/OpenMP/target_parallel_default_messages.cpp b/clang/test/OpenMP/target_parallel_default_messages.cpp
index 7d2990b780a..40f31b84848 100644
--- a/clang/test/OpenMP/target_parallel_default_messages.cpp
+++ b/clang/test/OpenMP/target_parallel_default_messages.cpp
@@ -4,10 +4,15 @@ void foo();
 
 int main(int argc, char **argv) {
   #pragma omp target parallel default // expected-error {{expected '(' after 'default'}}
+  foo();
   #pragma omp target parallel default ( // expected-error {{expected 'none' or 'shared' in OpenMP clause 'default'}} expected-error {{expected ')'}} expected-note {{to match this '('}}
+  foo();
   #pragma omp target parallel default () // expected-error {{expected 'none' or 'shared' in OpenMP clause 'default'}}
+  foo();
   #pragma omp target parallel default (none // expected-error {{expected ')'}} expected-note {{to match this '('}}
+  foo();
   #pragma omp target parallel default (shared), default(shared) // expected-error {{directive '#pragma omp target parallel' cannot contain more than one 'default' clause}}
+  foo();
   #pragma omp target parallel default (x) // expected-error {{expected 'none' or 'shared' in OpenMP clause 'default'}}
   foo();
 
@@ -15,6 +20,7 @@ int main(int argc, char **argv) {
   ++argc; // expected-error {{variable 'argc' must have explicitly specified data sharing attributes}}
 
   #pragma omp target parallel default(none)
+  foo();
   #pragma omp target parallel default(shared)
   ++argc;
   return 0;