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

llvm-svn: 342517

1 files changed, 15 insertions, 0 deletions

diff --git a/clang/lib/Frontend/DependencyFile.cpp b/clang/lib/Frontend/DependencyFile.cpp
index a3f3479..fdccd91 100644
--- a/clang/lib/Frontend/DependencyFile.cpp
+++ b/clang/lib/Frontend/DependencyFile.cpp
@@ -200,6 +200,10 @@ public:
                           const Module *Imported,
                           SrcMgr::CharacteristicKind FileType) override;
 
+  void HasInclude(SourceLocation Loc, StringRef SpelledFilename, bool IsAngled,
+                  const FileEntry *File,
+                  SrcMgr::CharacteristicKind FileType) override;
+
   void EndOfMainFile() override {
     OutputDependencyFile();
   }
@@ -328,6 +332,17 @@ void DFGImpl::InclusionDirective(SourceLocation HashLoc,
   }
 }
 
+void DFGImpl::HasInclude(SourceLocation Loc, StringRef SpelledFilename,
+                         bool IsAngled, const FileEntry *File,
+                         SrcMgr::CharacteristicKind FileType) {
+  if (!File)
+    return;
+  StringRef Filename = File->getName();
+  if (!FileMatchesDepCriteria(Filename.data(), FileType))
+    return;
+  AddFilename(llvm::sys::path::remove_leading_dotslash(Filename));
+}
+
 bool DFGImpl::AddFilename(StringRef Filename) {
   if (FilesSet.insert(Filename).second) {
     Files.push_back(Filename);