[clang] [OpenACC] Implement AST for OpenACC Compute Constructs (PR #81188)

[Erich Keane via cfe-commits]

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+//===- StmtOpenACC.h - Classes for OpenACC directives  ----------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+/// \file
+/// This file defines OpenACC AST classes for statement-level contructs.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_AST_STMTOPENACC_H
+#define LLVM_CLANG_AST_STMTOPENACC_H
+
+#include "clang/AST/Stmt.h"
+#include "clang/Basic/OpenACCKinds.h"
+#include "clang/Basic/SourceLocation.h"
+
+namespace clang {
+/// This is the base class for an OpenACC statement-level construct, other
+/// construct types are expected to inherit from this.
+class OpenACCConstructStmt : public Stmt {
+  friend class ASTStmtWriter;
+  friend class ASTStmtReader;
+  /// The directive kind. Each implementation of this interface should handle
+  /// specific kinds.
+  OpenACCDirectiveKind Kind = OpenACCDirectiveKind::Invalid;
+  /// The location of the directive statement, from the '#' to the last token of
+  /// the directive.
+  SourceRange Range;
+
+  // TODO OPENACC: Clauses should probably be collected in this class.
+
+protected:
+  OpenACCConstructStmt(StmtClass SC, OpenACCDirectiveKind K,
+                       SourceLocation Start, SourceLocation End)
+      : Stmt(SC), Kind(K), Range(Start, End) {}
+
+public:
+  OpenACCDirectiveKind getDirectiveKind() const { return Kind; }
+
+  static bool classof(const Stmt *S) {
+    return S->getStmtClass() >= firstOpenACCConstructStmtConstant &&
+           S->getStmtClass() <= lastOpenACCConstructStmtConstant;
+  }
+
+  SourceLocation getBeginLoc() const { return Range.getBegin(); }
+  SourceLocation getEndLoc() const { return Range.getEnd(); }
+
+  child_range children() {
+    return child_range(child_iterator(), child_iterator());
+  }
+
+  const_child_range children() const {
+    return const_cast<OpenACCConstructStmt *>(this)->children();
+  }
+};
+
+/// This is a base class for any OpenACC statement-level constructs that have an
+/// associated statement. This class is not intended to be instantiated, but is
+/// a convenient place to hold the associated statement.
+class OpenACCAssociatedStmtConstruct : public OpenACCConstructStmt {
+  friend class ASTStmtWriter;
+  friend class ASTStmtReader;
+  template <typename Derived> friend class RecursiveASTVisitor;
+  Stmt *AssociatedStmt = nullptr;
+
+protected:
+  OpenACCAssociatedStmtConstruct(StmtClass SC, OpenACCDirectiveKind K,
+                                 SourceLocation Start, SourceLocation End)
+      : OpenACCConstructStmt(SC, K, Start, End) {}
+
+  void setAssociatedStmt(Stmt *S) { AssociatedStmt = S; }
+  Stmt *getAssociatedStmt() { return AssociatedStmt; }
+  const Stmt *getAssociatedStmt() const {
+    return const_cast<OpenACCAssociatedStmtConstruct *>(this)
+        ->getAssociatedStmt();
+  }
+
+public:
+  child_range children() {
+    if (getAssociatedStmt())
+      return child_range(&AssociatedStmt, &AssociatedStmt + 1);
+    return child_range(child_iterator(), child_iterator());
+  }
+
+  const_child_range children() const {
+    return const_cast<OpenACCAssociatedStmtConstruct *>(this)->children();
+  }
+};
+/// This class represents a compute construct, representing a 'Kind' of
+/// `parallel', 'serial', or 'kernel'. These constructs are associated with a
+/// 'structured block', defined as:
+///
+///  in C or C++, an executable statement, possibly compound, with a single
+///  entry at the top and a single exit at the bottom
+///
+/// At the moment there is no real motivation to have a different AST node for
+/// those three, as they are semantically identical, and have only minor
+/// differences in the permitted list of clauses, which can be differentiated by
+/// the 'Kind'.
+class OpenACCComputeConstruct : public OpenACCAssociatedStmtConstruct {
+  friend class ASTStmtWriter;
+  friend class ASTStmtReader;
+  OpenACCComputeConstruct()
+      : OpenACCAssociatedStmtConstruct(OpenACCComputeConstructClass,
+                                       OpenACCDirectiveKind::Invalid,
+                                       SourceLocation{}, SourceLocation{}) {}
+
+  OpenACCComputeConstruct(OpenACCDirectiveKind K, SourceLocation Start,
+                          SourceLocation End)
+      : OpenACCAssociatedStmtConstruct(OpenACCComputeConstructClass, K, Start,
+                                       End) {
+    assert((K == OpenACCDirectiveKind::Parallel ||
+            K == OpenACCDirectiveKind::Serial ||
+            K == OpenACCDirectiveKind::Kernels) &&
+           "Only parallel, serial, and kernels constructs should be "
+           "represented by this type");
+  }
+
+public:
+  static bool classof(const Stmt *T) {
+    return T->getStmtClass() == OpenACCComputeConstructClass;
+  }
+
+  static OpenACCComputeConstruct *CreateEmpty(const ASTContext &C, EmptyShell);
+  static OpenACCComputeConstruct *Create(const ASTContext &C,
+                                         OpenACCDirectiveKind K,
+                                         SourceLocation BeginLoc,
+                                         SourceLocation EndLoc);
+
+  void setStructuredBlock(Stmt *S) { setAssociatedStmt(S); }
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erichkeane wrote:

Ah, that makes sense, thanks for clarifying! I think I can befriend ASTContext and get all my functionality out with the 'build'/'rebuild'/etc functions.

https://github.com/llvm/llvm-project/pull/81188