Modules - fix exclude header with umbrella directory

[jtsoftware]

Summary

This patch removes some code that seems to interfere with clang handling "exclude header" fields correctly. "exclude header" fields in the module map should always be relative to the module map, not the umbrella directory. This still needs a test case, which I'll get to next, if this seems correct. Tracing in the debugger shows that the exclude is handled correctly, and all clang "test" tests pass.

[rsmith]

I'm hesitant to say this LGTM, since this code was clearly added deliberately, but I'm having a hard time understanding why we'd want strange (and subtly-broken) rules for umbrella directories. Why is the model not simply that they implicitly generate a bunch of submodules?

Also, this patch should have an accompanying testcase showing that it fixes the behavior of exclude header when combined with umbrella headers.

[benlangmuir]

I chatted with Doug and we agreed this looks good to remove.

You'll need to fix this test, probably by just removing the exclude header "y/b.h", which looks wrong:
FAIL: Clang :: Modules/exclude-header.c (3575 of 7161)

[alexr]

This was r206342.

lib/Lex/ModuleMap.cpp

class ModuleMapParser {
     void parseUmbrellaDirDecl(SourceLocation UmbrellaLoc);
     void parseExportDecl();
     void parseUseDecl();
     void parseLinkDecl();
     void parseConfigMacros();
     void parseConflict();
     void parseInferredModuleDecl(bool Framework, bool Explicit);
     bool parseOptionalAttributes(Attributes &Attrs);
     
-    const DirectoryEntry *getOverriddenHeaderSearchDir();
-    
   public:
     explicit ModuleMapParser(Lexer &L, SourceManager &SourceMgr, 
                              const TargetInfo *Target,
                              DiagnosticsEngine &Diags,
                              ModuleMap &Map,
                              const DirectoryEntry *Directory,
                              const DirectoryEntry *BuiltinIncludeDir,
                              bool IsSystem)
void ModuleMapParser::parseHeaderDecl(MMToken::TokenKind LeadingToken,
 
   // Look for this file.
   const FileEntry *File = 0;
   const FileEntry *BuiltinFile = 0;
   SmallString<128> PathName;
   if (llvm::sys::path::is_absolute(Header.FileName)) {
     PathName = Header.FileName;
     File = SourceMgr.getFileManager().getFile(PathName);
-  } else if (const DirectoryEntry *Dir = getOverriddenHeaderSearchDir()) {
-    PathName = Dir->getName();
-    llvm::sys::path::append(PathName, Header.FileName);
-    File = SourceMgr.getFileManager().getFile(PathName);
   } else {
     // Search for the header file within the search directory.
     PathName = Directory->getName();
     unsigned PathLength = PathName.size();
     
     if (ActiveModule->isPartOfFramework()) {
       appendSubframeworkPaths(ActiveModule, PathName);
       
while (Tok.is(MMToken::LSquare)) {
 
     if (Tok.is(MMToken::RSquare))
       consumeToken();
   }
 
   return HadError;
 }
 
-/// \brief If there is a specific header search directory due the presence
-/// of an umbrella directory, retrieve that directory. Otherwise, returns null.
-const DirectoryEntry *ModuleMapParser::getOverriddenHeaderSearchDir() {
-  for (Module *Mod = ActiveModule; Mod; Mod = Mod->Parent) {
-    // If we have an umbrella directory, use that.
-    if (Mod->hasUmbrellaDir())
-      return Mod->getUmbrellaDir();
-    
-    // If we have a framework directory, stop looking.
-    if (Mod->IsFramework)
-      return 0;
-  }
-  
-  return 0;
-}
-
 /// \brief Parse a module map file.
 ///
 ///   module-map-file:
 ///     module-declaration*
 bool ModuleMapParser::parseModuleMapFile() {
   do {
     switch (Tok.Kind) {
     case MMToken::EndOfFile: