[OpenACC] Implement Sema work for OpenACC Clauses

clang/include/clang/Basic/DiagnosticSemaKinds.td

@@ -12252,6 +12252,8 @@ def warn_acc_clause_unimplemented
 def err_acc_construct_appertainment
     : Error<"OpenACC construct '%0' cannot be used here; it can only "
             "be used in a statement context">;
+def err_acc_clause_appertainment
+    : Error<"OpenACC '%1' clause is not valid on '%0' directive">;
 def err_acc_branch_in_out_compute_construct
     : Error<"invalid %select{branch|return|throw}0 %select{out of|into}1 "
             "OpenACC Compute Construct">;

clang/include/clang/Parse/Parser.h

@@ -41,6 +41,7 @@ namespace clang {
   class InMessageExpressionRAIIObject;
   class PoisonSEHIdentifiersRAIIObject;
   class OMPClause;
+  class OpenACCClause;
   class ObjCTypeParamList;
   struct OMPTraitProperty;
   struct OMPTraitSelector;
@@ -3594,11 +3595,26 @@ class Parser : public CodeCompletionHandler {
     OpenACCDirectiveKind DirKind;
     SourceLocation StartLoc;
     SourceLocation EndLoc;
-    // TODO OpenACC: Add Clause list here once we have a type for that.
+    SmallVector<OpenACCClause *> Clauses;
     // TODO OpenACC: As we implement support for the Atomic, Routine, Cache, and
     // Wait constructs, we likely want to put that information in here as well.
   };
 
+  /// Represents the 'error' state of parsing an OpenACC Clause, and stores
+  /// whether we can continue parsing, or should give up on the directive.
+  enum class OpenACCParseCanContinue { Cannot = 0, Can = 1 };
+
+  /// A type to represent the state of parsing an OpenACC Clause. Situations
+  /// that result in an OpenACCClause pointer are a success and can continue
+  /// parsing, however some other situations can also continue.
+  /// FIXME: This is better represented as a std::expected when we get C++23.
+  using OpenACCClauseParseResult =
+      llvm::PointerIntPair<OpenACCClause *, 1, OpenACCParseCanContinue>;
+
+  OpenACCClauseParseResult OpenACCCanContinue();
+  OpenACCClauseParseResult OpenACCCannotContinue();
+  OpenACCClauseParseResult OpenACCSuccess(OpenACCClause *Clause);
+
   /// Parses the OpenACC directive (the entire pragma) including the clause
   /// list, but does not produce the main AST node.
   OpenACCDirectiveParseInfo ParseOpenACCDirective();
@@ -3613,12 +3629,18 @@ class Parser : public CodeCompletionHandler {
   bool ParseOpenACCClauseVarList(OpenACCClauseKind Kind);
   /// Parses any parameters for an OpenACC Clause, including required/optional
   /// parens.
-  bool ParseOpenACCClauseParams(OpenACCDirectiveKind DirKind,
-                                OpenACCClauseKind Kind);
-  /// Parses a single clause in a clause-list for OpenACC.
-  bool ParseOpenACCClause(OpenACCDirectiveKind DirKind);
+  OpenACCClauseParseResult
+  ParseOpenACCClauseParams(ArrayRef<const OpenACCClause *> ExistingClauses,
+                           OpenACCDirectiveKind DirKind, OpenACCClauseKind Kind,
+                           SourceLocation ClauseLoc);
+  /// Parses a single clause in a clause-list for OpenACC. Returns nullptr on
+  /// error.
+  OpenACCClauseParseResult
+  ParseOpenACCClause(ArrayRef<const OpenACCClause *> ExistingClauses,
+                     OpenACCDirectiveKind DirKind);
   /// Parses the clause-list for an OpenACC directive.
-  void ParseOpenACCClauseList(OpenACCDirectiveKind DirKind);
+  SmallVector<OpenACCClause *>
+  ParseOpenACCClauseList(OpenACCDirectiveKind DirKind);
   bool ParseOpenACCWaitArgument();
   /// Parses the clause of the 'bind' argument, which can be a string literal or
   /// an ID expression.

clang/include/clang/Sema/SemaOpenACC.h

@@ -21,13 +21,46 @@
 #include "clang/Sema/SemaBase.h"
 
 namespace clang {
+class OpenACCClause;
 
 class SemaOpenACC : public SemaBase {
 public:
+  /// A type to represent all the data for an OpenACC Clause that has been
+  /// parsed, but not yet created/semantically analyzed. This is effectively a
+  /// discriminated union on the 'Clause Kind', with all of the individual
+  /// clause details stored in a std::variant.
+  class OpenACCParsedClause {
+    OpenACCDirectiveKind DirKind;
+    OpenACCClauseKind ClauseKind;
+    SourceRange ClauseRange;
+    SourceLocation LParenLoc;
+
+    // TODO OpenACC: Add variant here to store details of individual clauses.
+
+  public:
+    OpenACCParsedClause(OpenACCDirectiveKind DirKind,
+                        OpenACCClauseKind ClauseKind, SourceLocation BeginLoc)
+        : DirKind(DirKind), ClauseKind(ClauseKind), ClauseRange(BeginLoc, {}) {}
+
+    OpenACCDirectiveKind getDirectiveKind() const { return DirKind; }
+
+    OpenACCClauseKind getClauseKind() const { return ClauseKind; }
+
+    SourceLocation getBeginLoc() const { return ClauseRange.getBegin(); }
+
+    SourceLocation getLParenLoc() const { return LParenLoc; }
+
+    SourceLocation getEndLoc() const { return ClauseRange.getEnd(); }
+
+    void setLParenLoc(SourceLocation EndLoc) { LParenLoc = EndLoc; }
+    void setEndLoc(SourceLocation EndLoc) { ClauseRange.setEnd(EndLoc); }
+  };
+
   SemaOpenACC(Sema &S);
 
   /// Called after parsing an OpenACC Clause so that it can be checked.
-  bool ActOnClause(OpenACCClauseKind ClauseKind, SourceLocation StartLoc);
+  OpenACCClause *ActOnClause(ArrayRef<const OpenACCClause *> ExistingClauses,
+                             OpenACCParsedClause &Clause);
 
   /// Called after the construct has been parsed, but clauses haven't been
   /// parsed.  This allows us to diagnose not-implemented, as well as set up any
@@ -53,7 +86,10 @@ class SemaOpenACC : public SemaBase {
   /// declaration group or associated statement.
   StmtResult ActOnEndStmtDirective(OpenACCDirectiveKind K,
                                    SourceLocation StartLoc,
-                                   SourceLocation EndLoc, StmtResult AssocStmt);
+                                   SourceLocation EndLoc,
+                                   ArrayRef<OpenACCClause *> Clauses,
+                                   StmtResult AssocStmt);
+
   /// Called after the directive has been completely parsed, including the
   /// declaration group or associated statement.
   DeclGroupRef ActOnEndDeclDirective();