[flang-commits] [flang] [llvm] [flang][OpenMP] Add parsing and semantic checks for USES_ALLOCATORS (PR #213955)

[Sairudra More via flang-commits]

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@@ -5385,6 +5386,329 @@ void OmpStructureChecker::Enter(const parser::OmpClause::UseDeviceAddr &x) {
   }
 }
 
+static constexpr std::string_view predefinedAllocatorNames[]{
+    "omp_default_mem_alloc", "omp_large_cap_mem_alloc", "omp_const_mem_alloc",
+    "omp_high_bw_mem_alloc", "omp_low_lat_mem_alloc", "omp_cgroup_mem_alloc",
+    "omp_pteam_mem_alloc", "omp_thread_mem_alloc"};
+
+static constexpr std::string_view predefinedMemSpaceNames[]{
+    "omp_default_mem_space", "omp_large_cap_mem_space", "omp_const_mem_space",
+    "omp_high_bw_mem_space", "omp_low_lat_mem_space"};
+
+// omp_null_allocator and omp_null_mem_space are not themselves predefined
+// handles, but [6.0:315-316] gives each its own allowance.
+static constexpr std::string_view nullAllocatorName[]{"omp_null_allocator"};
+static constexpr std::string_view nullMemSpaceName[]{"omp_null_mem_space"};
+
+// Whether the ultimate symbol is an entity of the intrinsic omp_lib module
+// shipped with the compiler, as opposed to a same-named entity of a
+// user-defined module.
+static bool IsIntrinsicOmpLibEntity(const Symbol &ultimate) {
+  const Scope &scope{ultimate.owner()};
+  if (!scope.IsModule()) {
+    return false;
+  }
+  const Symbol *module{scope.symbol()};
+  return module && module->name() == "omp_lib" &&
+      scope.parent().IsIntrinsicModules();
+}
+
+// Recognition of a predefined allocator or memory space differs by version.
+//
+// [5.2:182] asks whether the allocator *is* a predefined allocator, so it
+// identifies the entity: a use-associated rename of the intrinsic omp_lib
+// entity still denotes it, while an unrelated declaration -- even one with the
+// same spelling, the same value, or in a user module named omp_lib -- does not.
+//
+// [6.0:315] instead asks whether the allocator is an identifier that *matches
+// the name of* a predefined allocator, which is a property of the identifier
+// written in the clause, not of the entity it resolves to. A local declaration
+// of a predefined spelling therefore qualifies, while a rename to some other
+// name does not, even when it denotes the intrinsic entity.
+static bool IsPredefinedHandle(const parser::Name &name,
+    llvm::ArrayRef<std::string_view> names, unsigned version) {
+  if (version >= 60) {
+    return llvm::is_contained(names, name.ToString());
+  }
----------------
Saieiei wrote:

The Copilot comment is incorrect.
`parser::Name` uses the already-lowercased cooked source

https://github.com/llvm/llvm-project/pull/213955