[Flang][OpenMP][Parser] Resolve Declare Target Directive Symbols

Currently symbols are not resolved for declare target
after they've been modified by prior passes. This can
lead to missing or incorrect symbols in subsequent
compiler phases when declare target is used with
more complex types e.g. common block.

This patch should allow these symbols to be
resolved appropriately.

Reviewers: kiranchandramohan

Differential Revision: https://reviews.llvm.org/D151993

flang/lib/Semantics/resolve-directives.cpp

@@ -330,6 +330,9 @@ class OmpAttributeVisitor : DirectiveAttributeVisitor<llvm::omp::Directive> {
   }
   void Post(const parser::OpenMPRequiresConstruct &) { PopContext(); }
 
+  bool Pre(const parser::OpenMPDeclareTargetConstruct &);
+  void Post(const parser::OpenMPDeclareTargetConstruct &) { PopContext(); }
+
   bool Pre(const parser::OpenMPThreadprivate &);
   void Post(const parser::OpenMPThreadprivate &) { PopContext(); }
 
@@ -520,7 +523,7 @@ class OmpAttributeVisitor : DirectiveAttributeVisitor<llvm::omp::Directive> {
       Symbol::Flag::OmpUseDeviceAddr};
 
   static constexpr Symbol::Flags ompFlagsRequireMark{
-      Symbol::Flag::OmpThreadprivate};
+      Symbol::Flag::OmpThreadprivate, Symbol::Flag::OmpDeclareTarget};
 
   static constexpr Symbol::Flags dataCopyingAttributeFlags{
       Symbol::Flag::OmpCopyIn, Symbol::Flag::OmpCopyPrivate};
@@ -1468,6 +1471,25 @@ bool OmpAttributeVisitor::Pre(const parser::OpenMPCriticalConstruct &x) {
   return true;
 }
 
+bool OmpAttributeVisitor::Pre(const parser::OpenMPDeclareTargetConstruct &x) {
+  PushContext(x.source, llvm::omp::Directive::OMPD_declare_target);
+  const auto &spec{std::get<parser::OmpDeclareTargetSpecifier>(x.t)};
+  if (const auto *objectList{parser::Unwrap<parser::OmpObjectList>(spec.u)}) {
+    ResolveOmpObjectList(*objectList, Symbol::Flag::OmpDeclareTarget);
+  } else if (const auto *clauseList{
+                 parser::Unwrap<parser::OmpClauseList>(spec.u)}) {
+    for (const auto &clause : clauseList->v) {
+      if (const auto *toClause{std::get_if<parser::OmpClause::To>(&clause.u)}) {
+        ResolveOmpObjectList(toClause->v, Symbol::Flag::OmpDeclareTarget);
+      } else if (const auto *linkClause{
+                     std::get_if<parser::OmpClause::Link>(&clause.u)}) {
+        ResolveOmpObjectList(linkClause->v, Symbol::Flag::OmpDeclareTarget);
+      }
+    }
+  }
+  return true;
+}
+
 bool OmpAttributeVisitor::Pre(const parser::OpenMPThreadprivate &x) {
   PushContext(x.source, llvm::omp::Directive::OMPD_threadprivate);
   const auto &list{std::get<parser::OmpObjectList>(x.t)};

flang/test/Semantics/OpenMP/declare-target-common-block.f90

@@ -0,0 +1,10 @@
+! RUN: %flang_fc1 -fopenmp -fdebug-dump-symbols %s | FileCheck %s
+
+PROGRAM main
+    !CHECK: one (OmpDeclareTarget) size=4 offset=0: ObjectEntity type: REAL(4)
+    !CHECK: two (OmpDeclareTarget) size=4 offset=4: ObjectEntity type: REAL(4)
+    !CHECK: numbers size=8 offset=0: CommonBlockDetails alignment=4: one two
+    REAL :: one, two
+    COMMON /numbers/ one, two
+    !$omp declare target(/numbers/)
+END