Add pragma to perform module import and use it in -E output.

Many of our supported configurations support modules but do not have any
first-class syntax to perform a module import. This leaves us with a problem:
there is no way to represent the expansion of a #include that imports a module
in the -E output for such languages. (We don't want to just leave it as a
#include because that requires the consumer of the preprocessed source to have
the same file system layout and include paths as the creator.)

This patch adds a new pragma:

  #pragma clang module import MODULE.NAME.HERE

that imports a module, and changes -E and -frewrite-includes to use it when
rewriting a #include that maps to a module import. We don't make any attempt
to use a native language syntax import if one exists, to get more consistent
output. (If in the future, @import and #include have different semantics in
some way, the pragma will track the #include semantics.)


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@301725 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 5 insertions, 0 deletions

diff --git a/include/clang/Lex/Preprocessor.h b/include/clang/Lex/Preprocessor.h
index 67b947bf84..b1a7325c34 100644
--- a/include/clang/Lex/Preprocessor.h
+++ b/include/clang/Lex/Preprocessor.h
@@ -1263,6 +1263,10 @@ public:
       CachedTokens[CachedLexPos-1] = Tok;
   }
 
+  /// Enter an annotation token into the token stream.
+  void EnterAnnotationToken(SourceRange Range, tok::TokenKind Kind,
+                            void *AnnotationVal);
+
   /// Update the current token to represent the provided
   /// identifier, in order to cache an action performed by typo correction.
   void TypoCorrectToken(const Token &Tok) {
@@ -1963,6 +1967,7 @@ public:
   void HandlePragmaPoison();
   void HandlePragmaSystemHeader(Token &SysHeaderTok);
   void HandlePragmaDependency(Token &DependencyTok);
+  void HandlePragmaModuleImport(Token &Tok);
   void HandlePragmaPushMacro(Token &Tok);
   void HandlePragmaPopMacro(Token &Tok);
   void HandlePragmaIncludeAlias(Token &Tok);