Add a callback for `__has_include` and use it for dependency scanning.

This adds a preprocessor callback for the `__has_include` and
`__has_include_next` directives.

Successful checking for the presence of a header should add it to the list of
header dependencies so this overrides the callback in the dependency scanner.

Patch by Pete Cooper with some additions by me.

rdar://problem/39545636

Differential Revision: https://reviews.llvm.org/D30882


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@342517 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 13 insertions, 0 deletions

diff --git a/include/clang/Lex/PPCallbacks.h b/include/clang/Lex/PPCallbacks.h
index 45c2d18da6..2448b34c8a 100644
--- a/include/clang/Lex/PPCallbacks.h
+++ b/include/clang/Lex/PPCallbacks.h
@@ -276,6 +276,12 @@ public:
                        SourceRange Range) {
   }
 
+  /// Hook called when a '__has_include' or '__has_include_next' directive is
+  /// read.
+  virtual void HasInclude(SourceLocation Loc, StringRef FileName, bool IsAngled,
+                          const FileEntry *File,
+                          SrcMgr::CharacteristicKind FileType) {}
+
   /// Hook called when a source range is skipped.
   /// \param Range The SourceRange that was skipped. The range begins at the
   /// \#if/\#else directive and ends after the \#endif/\#else directive.
@@ -443,6 +449,13 @@ public:
     Second->PragmaDiagnostic(Loc, Namespace, mapping, Str);
   }
 
+  void HasInclude(SourceLocation Loc, StringRef FileName, bool IsAngled,
+                  const FileEntry *File,
+                  SrcMgr::CharacteristicKind FileType) override {
+    First->HasInclude(Loc, FileName, IsAngled, File, FileType);
+    Second->HasInclude(Loc, FileName, IsAngled, File, FileType);
+  }
+
   void PragmaOpenCLExtension(SourceLocation NameLoc, const IdentifierInfo *Name,
                              SourceLocation StateLoc, unsigned State) override {
     First->PragmaOpenCLExtension(NameLoc, Name, StateLoc, State);