[clang][OpenMP] Add codegen for scope directive (#109197)

Added codegen for scope directive, enabled allocate and firstprivate
clauses, and added scope directive LIT test.

Testing
  - LIT tests (including new scope test).
  - OpenMP scope example test from 5.2 OpenMP API examples document.
  - Three executable scope tests from OpenMP_VV/sollve_vv suite.

clang/lib/CodeGen/CGStmt.cpp

@@ -420,7 +420,7 @@ void CodeGenFunction::EmitStmt(const Stmt *S, ArrayRef<const Attr *> Attrs) {
     CGM.ErrorUnsupported(S, "OpenMP dispatch directive");
     break;
   case Stmt::OMPScopeDirectiveClass:
-    CGM.ErrorUnsupported(S, "scope with FE outlining");
+    EmitOMPScopeDirective(cast<OMPScopeDirective>(*S));
     break;
   case Stmt::OMPMaskedDirectiveClass:
     EmitOMPMaskedDirective(cast<OMPMaskedDirective>(*S));

clang/lib/CodeGen/CGStmtOpenMP.cpp

@@ -4223,6 +4223,32 @@ void CodeGenFunction::EmitSections(const OMPExecutableDirective &S) {
   }
 }
 
+void CodeGenFunction::EmitOMPScopeDirective(const OMPScopeDirective &S) {
+  {
+    // Emit code for 'scope' region
+    auto &&CodeGen = [&S](CodeGenFunction &CGF, PrePostActionTy &Action) {
+      Action.Enter(CGF);
+      OMPPrivateScope PrivateScope(CGF);
+      (void)CGF.EmitOMPFirstprivateClause(S, PrivateScope);
+      CGF.EmitOMPPrivateClause(S, PrivateScope);
+      CGF.EmitOMPReductionClauseInit(S, PrivateScope);
+      (void)PrivateScope.Privatize();
+      CGF.EmitStmt(S.getInnermostCapturedStmt()->getCapturedStmt());
+      CGF.EmitOMPReductionClauseFinal(S, /*ReductionKind=*/OMPD_parallel);
+    };
+    auto LPCRegion =
+        CGOpenMPRuntime::LastprivateConditionalRAII::disable(*this, S);
+    OMPLexicalScope Scope(*this, S, OMPD_unknown);
+    CGM.getOpenMPRuntime().emitInlinedDirective(*this, OMPD_scope, CodeGen);
+  }
+  // Emit an implicit barrier at the end.
+  if (!S.getSingleClause<OMPNowaitClause>()) {
+    CGM.getOpenMPRuntime().emitBarrierCall(*this, S.getBeginLoc(), OMPD_scope);
+  }
+  // Check for outer lastprivate conditional update.
+  checkForLastprivateConditionalUpdate(*this, S);
+}
+
 void CodeGenFunction::EmitOMPSectionsDirective(const OMPSectionsDirective &S) {
   if (CGM.getLangOpts().OpenMPIRBuilder) {
     llvm::OpenMPIRBuilder &OMPBuilder = CGM.getOpenMPRuntime().getOMPBuilder();

clang/lib/CodeGen/CodeGenFunction.h

@@ -3823,6 +3823,7 @@ public:
   void EmitOMPInterchangeDirective(const OMPInterchangeDirective &S);
   void EmitOMPForDirective(const OMPForDirective &S);
   void EmitOMPForSimdDirective(const OMPForSimdDirective &S);
+  void EmitOMPScopeDirective(const OMPScopeDirective &S);
   void EmitOMPSectionsDirective(const OMPSectionsDirective &S);
   void EmitOMPSectionDirective(const OMPSectionDirective &S);
   void EmitOMPSingleDirective(const OMPSingleDirective &S);

clang/test/OpenMP/error_unsupport_feature.c

@@ -1,8 +0,0 @@
-// RUN: %clang_cc1 -emit-llvm-only -verify -fopenmp %s
-
-int main () {
-  int r = 0;
-#pragma omp scope reduction(+:r) // expected-error {{cannot compile this scope with FE outlining yet}}
-  r++;
-  return r;
-}

llvm/include/llvm/Frontend/OpenMP/OMP.td

@@ -887,6 +887,8 @@ def OMP_scope : Directive<"scope"> {
   let allowedClauses = [
     VersionedClause<OMPC_Private, 51>,
     VersionedClause<OMPC_Reduction, 51>,
+    VersionedClause<OMPC_FirstPrivate, 52>,
+    VersionedClause<OMPC_Allocate, 52>,
   ];
   let allowedOnceClauses = [
     VersionedClause<OMPC_NoWait, 51>,