[flang] Add semantic checks for threadprivate and declare target directives

This patch supports the following checks:
```
[5.1] 2.21.2 THREADPRIVATE Directive
The threadprivate directive must appear in the declaration section of
a scoping unit in which the common block or variable is declared.
[5.1] 2.14.7 Declare Target Directive
The directive must appear in the declaration section of a scoping unit
in which the common block or variable is declared.
```
Reviewed By: kiranchandramohan, shraiysh, NimishMishra

Differential Revision: https://reviews.llvm.org/D125767

flang/lib/Semantics/check-omp-structure.cpp

@@ -922,6 +922,8 @@ void OmpStructureChecker::CheckThreadprivateOrDeclareTargetVar(
         common::visitors{
             [&](const parser::Designator &) {
               if (const auto *name{parser::Unwrap<parser::Name>(ompObject)}) {
+                const auto &useScope{
+                    context_.FindScope(GetContext().directiveSource)};
                 const auto &declScope{
                     GetProgramUnitContaining(name->symbol->GetUltimate())};
                 const auto *sym =
@@ -967,6 +969,12 @@ void OmpStructureChecker::CheckThreadprivateOrDeclareTargetVar(
                       "declared in the scope of a module or have the SAVE "
                       "attribute, either explicitly or implicitly"_err_en_US,
                       ContextDirectiveAsFortran());
+                } else if (useScope != declScope) {
+                  context_.Say(name->source,
+                      "The %s directive and the common block or variable in it "
+                      "must appear in the same declaration section of a "
+                      "scoping unit"_err_en_US,
+                      ContextDirectiveAsFortran());
                 } else if (FindEquivalenceSet(*name->symbol)) {
                   context_.Say(name->source,
                       "A variable in a %s directive cannot appear in an "

flang/test/Semantics/omp-declare-target05.f90

@@ -0,0 +1,44 @@
+! RUN: %python %S/test_errors.py %s %flang_fc1 -fopenmp
+! OpenMP Version 5.1
+! Check OpenMP construct validity for the following directives:
+! 2.14.7 Declare Target Directive
+
+module mod0
+  integer :: mi
+
+contains
+  subroutine subm()
+    integer, save :: mmi
+
+    !ERROR: The DECLARE TARGET directive and the common block or variable in it must appear in the same declaration section of a scoping unit
+    !$omp declare target (mi)
+    mi = 1
+  contains
+    subroutine subsubm()
+      !ERROR: The DECLARE TARGET directive and the common block or variable in it must appear in the same declaration section of a scoping unit
+      !$omp declare target (mmi)
+    end
+  end
+end
+
+module mod1
+  integer :: mod_i
+end
+
+program main
+  use mod1
+  integer, save :: i
+  integer :: j
+
+  !ERROR: The DECLARE TARGET directive and the common block or variable in it must appear in the same declaration section of a scoping unit
+  !$omp declare target (mod_i)
+
+contains
+  subroutine sub()
+    !ERROR: The DECLARE TARGET directive and the common block or variable in it must appear in the same declaration section of a scoping unit
+    !ERROR: The DECLARE TARGET directive and the common block or variable in it must appear in the same declaration section of a scoping unit
+    !$omp declare target (i, j)
+    i = 1
+    j = 1
+  end
+end

flang/test/Semantics/omp-threadprivate05.f90

@@ -0,0 +1,44 @@
+! RUN: %python %S/test_errors.py %s %flang_fc1 -fopenmp
+! OpenMP Version 5.1
+! Check OpenMP construct validity for the following directives:
+! 2.21.2 Threadprivate Directive
+
+module mod0
+  integer :: mi
+
+contains
+  subroutine subm()
+    integer, save :: mmi
+
+    !ERROR: The THREADPRIVATE directive and the common block or variable in it must appear in the same declaration section of a scoping unit
+    !$omp threadprivate(mi)
+    mi = 1
+  contains
+    subroutine subsubm()
+      !ERROR: The THREADPRIVATE directive and the common block or variable in it must appear in the same declaration section of a scoping unit
+      !$omp threadprivate(mmi)
+    end
+  end
+end
+
+module mod1
+  integer :: mod_i
+end
+
+program main
+  use mod1
+  integer, save :: i
+  integer :: j
+
+  !ERROR: The THREADPRIVATE directive and the common block or variable in it must appear in the same declaration section of a scoping unit
+  !$omp threadprivate(mod_i)
+
+contains
+  subroutine sub()
+    !ERROR: The THREADPRIVATE directive and the common block or variable in it must appear in the same declaration section of a scoping unit
+    !ERROR: The THREADPRIVATE directive and the common block or variable in it must appear in the same declaration section of a scoping unit
+    !$omp threadprivate(i, j)
+    i = 1
+    j = 1
+  end
+end