Introduce support for a simple module import declaration, which

loads the named module. The syntax itself is intentionally hideous and
will be replaced at some later point with something more
palatable. For now, we're focusing on the semantics:
  - Module imports are handled first by the preprocessor (to get macro
  definitions) and then the same tokens are also handled by the parser
  (to get declarations). If both happen (as in normal compilation),
  the second one is redundant, because we currently have no way to
  hide macros or declarations when loading a module. Chris gets credit
  for this mad-but-workable scheme.
  - The Preprocessor now holds on to a reference to a module loader,
  which is responsible for loading named modules. CompilerInstance is
  the only important module loader: it now knows how to create and
  wire up an AST reader on demand to actually perform the module load.
  - We search for modules in the include path, using the module name
  with the suffix ".pcm" (precompiled module) for the file name. This
  is a temporary hack; we hope to improve the situation in the
  future.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@138679 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 55 insertions, 0 deletions

diff --git a/include/clang/Lex/ModuleLoader.h b/include/clang/Lex/ModuleLoader.h
index e69de29bb2..72ec0e3ebc 100644
--- a/include/clang/Lex/ModuleLoader.h
+++ b/include/clang/Lex/ModuleLoader.h
@@ -0,0 +1,55 @@
+//===--- ModuleLoader.h - Module Loader Interface ---------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+//  This file defines the ModuleLoader interface, which is responsible for 
+//  loading named modules.
+//
+//===----------------------------------------------------------------------===//
+#ifndef LLVM_CLANG_LEX_MODULE_LOADER_H
+#define LLVM_CLANG_LEX_MODULE_LOADER_H
+
+#include "clang/Basic/SourceLocation.h"
+
+namespace clang {
+
+class IdentifierInfo;
+  
+/// \brief An opaque key that is used to describe the module and can be 
+/// interpreted by the module loader itself.
+typedef void *ModuleKey;
+  
+/// \brief Abstract interface for a module loader.
+///
+/// This abstract interface describes a module loader, which is responsible
+/// for resolving a module name (e.g., "std") to an actual module file, and
+/// then loading that module.
+class ModuleLoader {
+public:
+  virtual ~ModuleLoader();
+  
+  /// \brief Attempt to load the given module.
+  ///
+  /// This routine attempts to load the module described by the given 
+  /// parameters.
+  ///
+  /// \param ImportLoc The location of the 'import' keyword.
+  /// \param ModuleName The name of the module to be loaded.
+  /// \param ModuleNameLoc The location of the module name.
+  ///
+  /// \returns If successful, a non-NULL module key describing this module.
+  /// Otherwise, returns NULL to indicate that the module could not be
+  /// loaded.
+  virtual ModuleKey loadModule(SourceLocation ImportLoc, 
+                               IdentifierInfo &ModuleName,
+                               SourceLocation ModuleNameLoc) = 0;
+};
+  
+}
+
+#endif