[clang] [clang][modules] Separate parsing of modulemaps (PR #119740)

[Jan Svoboda via cfe-commits]

================
@@ -0,0 +1,164 @@
+//===- ModuleMapFile.h - Parsing and representation -------------*- 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_LEX_MODULEMAPFILE_H
+#define LLVM_CLANG_LEX_MODULEMAPFILE_H
+
+#include "clang/Basic/LLVM.h"
+// TODO: Consider moving ModuleId to another header, parsing a modulemap file is
+//   intended to not depend on anything about the clang::Module class.
+#include "clang/Basic/Module.h"
+#include "clang/Basic/SourceLocation.h"
+#include "llvm/ADT/StringRef.h"
+
+#include <optional>
+#include <variant>
+
+namespace clang {
+
+class DiagnosticsEngine;
+class SourceManager;
+
+namespace modulemap {
+
+struct ExportDecl;
+
+/// All declarations that can appear in a `module` declaration.
+using Decl =
+    std::variant<struct RequiresDecl, struct HeaderDecl, struct UmbrellaDirDecl,
+                 struct ModuleDecl, struct ExcludeDecl, struct ExportDecl,
+                 struct ExportAsDecl, struct ExternModuleDecl, struct UseDecl,
+                 struct LinkDecl, struct ConfigMacrosDecl, struct ConflictDecl>;
+
+struct RequiresFeature {
+  SourceLocation Location;
+  StringRef Feature;
+  bool RequiredState = true; /// False if preceded by '!'.
+};
+
+struct RequiresDecl {
+  SourceLocation Location;
+  std::vector<RequiresFeature> Features;
+};
+
+struct HeaderDecl {
+  SourceLocation Location;
+  StringRef Path;
+  SourceLocation PathLoc;
+  std::optional<int64_t> Size;
+  std::optional<int64_t> MTime;
+  LLVM_PREFERRED_TYPE(bool)
+  unsigned Private : 1;
+  LLVM_PREFERRED_TYPE(bool)
+  unsigned Textual : 1;
+  LLVM_PREFERRED_TYPE(bool)
+  unsigned Umbrella : 1;
+  LLVM_PREFERRED_TYPE(bool)
+  unsigned Excluded : 1;
+};
+
+struct UmbrellaDirDecl {
+  SourceLocation Location;
+  StringRef Path;
+};
+
+struct ModuleDecl {
+  SourceLocation Location; /// Points to the first keyword in the decl.
+  ModuleId Id;
+  ModuleAttributes Attrs;
+  std::vector<Decl> Decls;
----------------
jansvoboda11 wrote:

You can shrink the size from 128B to 120B by moving `ModuleId ` up.

https://github.com/llvm/llvm-project/pull/119740