[OpenMP] Add diagnostic for unterminated 'omp [begin] declare target'

[mikerice]

Summary

Warns when end-of-file is reached without seeing all matching
'omp end declare target' directives. The diagnostic shows the
location of the related begin directive.

[ABataev]

LG

[jdoerfert]

Cool! Can we have that for begin declare variant too :D ?

[mikerice]

In D126331#3538670, @jdoerfert wrote:

Cool! Can we have that for begin declare variant too :D ?

I'll take a look when I get a moment.

clang/include/clang/Basic/DiagnosticSemaKinds.td

 def err_omp_adjust_arg_multiple_clauses : Error<
   "'adjust_arg' argument %0 used in multiple clauses">;
 def err_omp_clause_requires_dispatch_construct : Error<
   "'%0' clause requires 'dispatch' context selector">;
 def err_omp_append_args_with_varargs : Error<
   "'append_args' is not allowed with varargs functions">;
 def err_openmp_vla_in_task_untied : Error<
   "variable length arrays are not supported in OpenMP tasking regions with 'untied' clause">;
+def warn_omp_unterminated_declare_target : Warning<
+  "expected '#pragma omp end declare target' at end of file to match '#pragma omp %0'">,
+  InGroup<SourceUsesOpenMP>;
 } // end of OpenMP category
 
 let CategoryName = "Related Result Type Issue" in {
 // Objective-C related result type compatibility
 def warn_related_result_type_compatibility_class : Warning<
   "method is expected to return an instance of its class type "
   "%diff{$, but is declared to return $|"
   ", but is declared to return different type}0,1">;

clang/include/clang/Sema/Sema.h

public:
   const DeclareTargetContextInfo ActOnOpenMPEndDeclareTargetDirective();
 
   /// Called once a target context is completed, that can be when a
   /// '#pragma omp end declare target' was encountered or when a
   /// '#pragma omp declare target' without declaration-definition-seq was
   /// encountered.
   void ActOnFinishedOpenMPDeclareTargetContext(DeclareTargetContextInfo &DTCI);
 
+  /// Report unterminated 'omp declare target' or 'omp begin declare target' at
+  /// the end of a compilation unit.
+  void DiagnoseUnterminatedOpenMPDeclareTarget();
+
   /// Searches for the provided declaration name for OpenMP declare target
   /// directive.
   NamedDecl *lookupOpenMPDeclareTargetName(Scope *CurScope,
                                            CXXScopeSpec &ScopeSpec,
                                            const DeclarationNameInfo &Id);
 
   /// Called on correct id-expression from the '#pragma omp declare target'.
   void ActOnOpenMPDeclareTargetName(NamedDecl *ND, SourceLocation Loc,

clang/lib/Sema/Sema.cpp

if (TUKind != TU_Prefix) {
     if (LangOpts.PCHInstantiateTemplates) {
       llvm::TimeTraceScope TimeScope("PerformPendingInstantiations");
       PerformPendingInstantiations();
     }
   }
 
   DiagnoseUnterminatedPragmaAlignPack();
   DiagnoseUnterminatedPragmaAttribute();
+  DiagnoseUnterminatedOpenMPDeclareTarget();
 
   // All delayed member exception specs should be checked or we end up accepting
   // incompatible declarations.
   assert(DelayedOverridingExceptionSpecChecks.empty());
   assert(DelayedEquivalentExceptionSpecChecks.empty());
 
   // All dllexport classes should have been processed already.
   assert(DelayedDllExportClasses.empty());

clang/lib/Sema/SemaOpenMP.cpp

 }
 
 void Sema::ActOnFinishedOpenMPDeclareTargetContext(
     DeclareTargetContextInfo &DTCI) {
   for (auto &It : DTCI.ExplicitlyMapped)
     ActOnOpenMPDeclareTargetName(It.first, It.second.Loc, It.second.MT, DTCI);
 }
 
+void Sema::DiagnoseUnterminatedOpenMPDeclareTarget() {
+  if (DeclareTargetNesting.empty())
+    return;
+  DeclareTargetContextInfo &DTCI = DeclareTargetNesting.back();
+  Diag(DTCI.Loc, diag::warn_omp_unterminated_declare_target)
+      << getOpenMPDirectiveName(DTCI.Kind);
+}
+
 NamedDecl *Sema::lookupOpenMPDeclareTargetName(Scope *CurScope,
                                                CXXScopeSpec &ScopeSpec,
                                                const DeclarationNameInfo &Id) {
   LookupResult Lookup(*this, Id, LookupOrdinaryName);
   LookupParsedName(Lookup, CurScope, &ScopeSpec, true);
 
   if (Lookup.isAmbiguous())
     return nullptr;

clang/test/OpenMP/Inputs/unterminated_declare_target_include.h

+// expected-warning@+1 {{expected '#pragma omp end declare target' at end of file to match '#pragma omp declare target'}}
+#pragma omp declare target
+void zxy();

clang/test/OpenMP/declare_target_messages.cpp

 // RUN: %clang_cc1 -triple x86_64-apple-macos10.7.0 -verify=expected,omp45 -fopenmp -fopenmp-version=45 -fnoopenmp-use-tls -ferror-limit 100 -o - %s
 // RUN: %clang_cc1 -triple x86_64-apple-macos10.7.0 -verify=expected,omp5,host5 -fopenmp -fopenmp-targets=x86_64-apple-macos10.7.0 -fnoopenmp-use-tls -ferror-limit 100 -o - %s
 // RUN: %clang_cc1 -triple x86_64-apple-macos10.7.0 -verify=expected,omp5,dev5 -fopenmp -fopenmp-is-device -fopenmp-targets=x86_64-apple-macos10.7.0 -aux-triple x86_64-apple-macos10.7.0 -fnoopenmp-use-tls -ferror-limit 100 -o - %s
 
 // RUN: %clang_cc1 -triple x86_64-apple-macos10.7.0 -verify=expected,omp5,host5 -fopenmp-simd -fopenmp-targets=x86_64-apple-macos10.7.0 -fnoopenmp-use-tls -ferror-limit 100 -o - %s
 // RUN: %clang_cc1 -triple x86_64-apple-macos10.7.0 -verify=expected,omp5,host5 -fopenmp-simd -fopenmp-is-device -fopenmp-targets=x86_64-apple-macos10.7.0 -fnoopenmp-use-tls -ferror-limit 100 -o - %s
 // RUN: %clang_cc1 -triple x86_64-apple-macos10.7.0 -verify=expected,omp45 -fopenmp-version=45 -fopenmp-simd -fnoopenmp-use-tls -ferror-limit 100 -o - %s
 // RUN: %clang_cc1 -triple x86_64-apple-macos10.7.0 -verify=expected,omp51 -fopenmp -fopenmp-version=51 -fnoopenmp-use-tls -ferror-limit 100 -o - %s
+// RUN: %clang_cc1 -triple x86_64-apple-macos10.7.0 -verify=expected,omp51 -fopenmp -fopenmp-version=51 -fnoopenmp-use-tls -ferror-limit 100 -DTESTEND=1 -o - %s
+// RUN: %clang_cc1 -triple x86_64-apple-macos10.7.0 -verify=expected,omp51 -fopenmp -fopenmp-version=51 -fnoopenmp-use-tls -ferror-limit 100 -I%S/Inputs -DTESTENDINC=1 -o - %s
+// RUN: %clang_cc1 -triple x86_64-apple-macos10.7.0 -verify=expected,omp51 -fopenmp-version=51 -fopenmp-simd -fnoopenmp-use-tls -ferror-limit 100 -o - %s
 // RUN: %clang_cc1 -triple x86_64-apple-macos10.7.0 -verify=expected,omp51 -fopenmp-version=51 -fopenmp-simd -fnoopenmp-use-tls -ferror-limit 100 -o - %s
 
 // RUN: %clang_cc1 -triple x86_64-apple-macos10.7.0 -verify=expected,omp5 -fopenmp -fnoopenmp-use-tls -ferror-limit 100 -o - %s
 #pragma omp end declare target // expected-error {{unexpected OpenMP directive '#pragma omp end declare target'}}
 
 int a, b, z; // omp5-error {{variable captured in declare target region must appear in a to clause}} // omp51-error {{variable captured in declare target region must appear in a to clause}}
 __thread int t; // expected-note {{defined as threadprivate or thread local}}
 

 void any7() {device();} // host5-error {{function with 'device_type(nohost)' is not available on host}}
 void any8() {any2();}
 
 int MultiDevTy;
 #pragma omp declare target to(MultiDevTy) device_type(any)    // omp45-error {{unexpected 'device_type' clause, only 'to' or 'link' clauses expected}}
 #pragma omp declare target to(MultiDevTy) device_type(host)   // omp45-error {{unexpected 'device_type' clause, only 'to' or 'link' clauses expected}} omp5-error {{'device_type(host)' does not match previously specified 'device_type(any)' for the same declaration}} omp51-error {{'device_type(host)' does not match previously specified 'device_type(any)' for the same declaration}}
 #pragma omp declare target to(MultiDevTy) device_type(nohost) // omp45-error {{unexpected 'device_type' clause, only 'to' or 'link' clauses expected}} omp5-error {{'device_type(nohost)' does not match previously specified 'device_type(any)' for the same declaration}} // omp51-error {{'device_type(nohost)' does not match previously specified 'device_type(any)' for the same declaration}}
 
-// TODO: Issue an error message error {{expected '#pragma omp end declare target'}} note {{to match this '#pragma omp declare target'}}
-#pragma omp declare target
+#if TESTENDINC
+#include "unterminated_declare_target_include.h"
+#elif TESTEND
+// expected-warning@+1 {{expected '#pragma omp end declare target' at end of file to match '#pragma omp declare target'}}
+#pragma omp declare target
+#else
+// expected-warning@+1 {{expected '#pragma omp end declare target' at end of file to match '#pragma omp begin declare target'}}
+#pragma omp begin declare target
+#endif