When loading a module that involves submodules (e.g., std.vector),

check whether the named submodules themselves are actually
valid, and drill down to the named submodule (although we don't do
anything with it yet). Perform typo correction on the submodule names
when possible.

llvm-svn: 145477

1 files changed, 150 insertions, 82 deletions

diff --git a/clang/lib/Frontend/CompilerInstance.cpp b/clang/lib/Frontend/CompilerInstance.cpp
index a72370312db..dfc98e8bfbe 100644
--- a/clang/lib/Frontend/CompilerInstance.cpp
+++ b/clang/lib/Frontend/CompilerInstance.cpp
@@ -1080,99 +1080,167 @@ ModuleKey CompilerInstance::loadModule(SourceLocation ImportLoc,
 
   StringRef ModuleName = Path[0].first->getName();
   SourceLocation ModuleNameLoc = Path[0].second;
-  
-  // Search for a module with the given name.
-  ModuleMap::Module *Module = 0;
-  std::string ModuleFileName;
-  const FileEntry *ModuleFile
-    = PP->getHeaderSearchInfo().lookupModule(ModuleName, Module,
-                                             &ModuleFileName);
 
-  // FIXME: Verify that the rest of the module path actually corresponds to
-  // a submodule, and pass that information through.
+  ModuleMap::Module *Module = 0;
+  const FileEntry *ModuleFile = 0;
   
-  bool BuildingModule = false;
-  if (!ModuleFile && Module) {
-    // The module is not cached, but we have a module map from which we can
-    // build the module.
-
-    // Check whether there is a cycle in the module graph.
-    SmallVectorImpl<std::string> &ModuleBuildPath
-      = getPreprocessorOpts().ModuleBuildPath;
-    SmallVectorImpl<std::string>::iterator Pos
-      = std::find(ModuleBuildPath.begin(), ModuleBuildPath.end(), ModuleName);
-    if (Pos != ModuleBuildPath.end()) {
-      llvm::SmallString<256> CyclePath;
-      for (; Pos != ModuleBuildPath.end(); ++Pos) {
-        CyclePath += *Pos;
-        CyclePath += " -> ";
+  // If we don't already have information on this module, load the module now.
+  KnownModule &Known = KnownModules[Path[0].first];
+  if (Known.isNull()) {  
+    // Search for a module with the given name.
+    std::string ModuleFileName;
+    ModuleFile
+      = PP->getHeaderSearchInfo().lookupModule(ModuleName, Module,
+                                               &ModuleFileName);
+
+    bool BuildingModule = false;
+    if (!ModuleFile && Module) {
+      // The module is not cached, but we have a module map from which we can
+      // build the module.
+
+      // Check whether there is a cycle in the module graph.
+      SmallVectorImpl<std::string> &ModuleBuildPath
+        = getPreprocessorOpts().ModuleBuildPath;
+      SmallVectorImpl<std::string>::iterator Pos
+        = std::find(ModuleBuildPath.begin(), ModuleBuildPath.end(), ModuleName);
+      if (Pos != ModuleBuildPath.end()) {
+        llvm::SmallString<256> CyclePath;
+        for (; Pos != ModuleBuildPath.end(); ++Pos) {
+          CyclePath += *Pos;
+          CyclePath += " -> ";
+        }
+        CyclePath += ModuleName;
+
+        getDiagnostics().Report(ModuleNameLoc, diag::err_module_cycle)
+          << ModuleName << CyclePath;
+        return 0;
       }
-      CyclePath += ModuleName;
 
-      getDiagnostics().Report(ModuleNameLoc, diag::err_module_cycle)
-        << ModuleName << CyclePath;
-      return 0;
+      getDiagnostics().Report(ModuleNameLoc, diag::warn_module_build)
+        << ModuleName;
+      BuildingModule = true;
+      compileModule(*this, Module, ModuleFileName);
+      ModuleFile = FileMgr->getFile(ModuleFileName);
     }
 
-    getDiagnostics().Report(ModuleNameLoc, diag::warn_module_build)
-      << ModuleName;
-    BuildingModule = true;
-    compileModule(*this, Module, ModuleFileName);
-    ModuleFile = FileMgr->getFile(ModuleFileName);
-  }
-
-  if (!ModuleFile) {
-    getDiagnostics().Report(ModuleNameLoc,
-                            BuildingModule? diag::err_module_not_built
-                                          : diag::err_module_not_found)
-      << ModuleName
-      << SourceRange(ImportLoc, ModuleNameLoc);
-    return 0;
-  }
+    if (!ModuleFile) {
+      getDiagnostics().Report(ModuleNameLoc,
+                              BuildingModule? diag::err_module_not_built
+                                            : diag::err_module_not_found)
+        << ModuleName
+        << SourceRange(ImportLoc, ModuleNameLoc);
+      return 0;
+    }
 
-  // If we don't already have an ASTReader, create one now.
-  if (!ModuleManager) {
-    if (!hasASTContext())
-      createASTContext();
-
-    std::string Sysroot = getHeaderSearchOpts().Sysroot;
-    const PreprocessorOptions &PPOpts = getPreprocessorOpts();
-    ModuleManager = new ASTReader(getPreprocessor(), *Context,
-                                  Sysroot.empty() ? "" : Sysroot.c_str(),
-                                  PPOpts.DisablePCHValidation,
-                                  PPOpts.DisableStatCache);
-    if (hasASTConsumer()) {
-      ModuleManager->setDeserializationListener(
-        getASTConsumer().GetASTDeserializationListener());
-      getASTContext().setASTMutationListener(
-        getASTConsumer().GetASTMutationListener());
+    // If we don't already have an ASTReader, create one now.
+    if (!ModuleManager) {
+      if (!hasASTContext())
+        createASTContext();
+
+      std::string Sysroot = getHeaderSearchOpts().Sysroot;
+      const PreprocessorOptions &PPOpts = getPreprocessorOpts();
+      ModuleManager = new ASTReader(getPreprocessor(), *Context,
+                                    Sysroot.empty() ? "" : Sysroot.c_str(),
+                                    PPOpts.DisablePCHValidation,
+                                    PPOpts.DisableStatCache);
+      if (hasASTConsumer()) {
+        ModuleManager->setDeserializationListener(
+          getASTConsumer().GetASTDeserializationListener());
+        getASTContext().setASTMutationListener(
+          getASTConsumer().GetASTMutationListener());
+      }
+      llvm::OwningPtr<ExternalASTSource> Source;
+      Source.reset(ModuleManager);
+      getASTContext().setExternalSource(Source);
+      if (hasSema())
+        ModuleManager->InitializeSema(getSema());
+      if (hasASTConsumer())
+        ModuleManager->StartTranslationUnit(&getASTConsumer());
     }
-    llvm::OwningPtr<ExternalASTSource> Source;
-    Source.reset(ModuleManager);
-    getASTContext().setExternalSource(Source);
-    if (hasSema())
-      ModuleManager->InitializeSema(getSema());
-    if (hasASTConsumer())
-      ModuleManager->StartTranslationUnit(&getASTConsumer());
-  }
 
-  // Try to load the module we found.
-  switch (ModuleManager->ReadAST(ModuleFile->getName(),
-                                 serialization::MK_Module)) {
-  case ASTReader::Success:
-    break;
+    // Try to load the module we found.
+    switch (ModuleManager->ReadAST(ModuleFile->getName(),
+                                   serialization::MK_Module)) {
+    case ASTReader::Success:
+      break;
 
-  case ASTReader::IgnorePCH:
-    // FIXME: The ASTReader will already have complained, but can we showhorn
-    // that diagnostic information into a more useful form?
-    return 0;
+    case ASTReader::IgnorePCH:
+      // FIXME: The ASTReader will already have complained, but can we showhorn
+      // that diagnostic information into a more useful form?
+      return 0;
 
-  case ASTReader::Failure:
-    // Already complained.
-    return 0;
+    case ASTReader::Failure:
+      // Already complained.
+      return 0;
+    }
+    
+    if (Module)
+      Known = Module;
+    else
+      Known = ModuleFile;
+  } else {
+    Module = Known.dyn_cast<ModuleMap::Module *>();
   }
-
-  // FIXME: The module file's FileEntry makes a poor key indeed!
-  return (ModuleKey)ModuleFile;
+  
+  // Verify that the rest of the module path actually corresponds to
+  // a submodule.
+  ModuleMap::Module *Sub = 0;
+  if (Module && Path.size() > 1) {
+    Sub = Module;
+    for (unsigned I = 1, N = Path.size(); I != N; ++I) {
+      StringRef Name = Path[I].first->getName();
+      llvm::StringMap<ModuleMap::Module *>::iterator Pos
+        = Sub->SubModules.find(Name);
+      
+      if (Pos == Sub->SubModules.end()) {
+        // Attempt to perform typo correction to find a module name that works.
+        llvm::SmallVector<StringRef, 2> Best;
+        unsigned BestEditDistance = (std::numeric_limits<unsigned>::max)();
+        
+        for (llvm::StringMap<ModuleMap::Module *>::iterator 
+                  I = Sub->SubModules.begin(), 
+               IEnd = Sub->SubModules.end();
+             I != IEnd; ++I) {
+          unsigned ED = Name.edit_distance(I->getValue()->Name,
+                                           /*AllowReplacements=*/true,
+                                           BestEditDistance);
+          if (ED <= BestEditDistance) {
+            if (ED < BestEditDistance)
+              Best.clear();
+            Best.push_back(I->getValue()->Name);
+          }
+        }
+        
+        // If there was a clear winner, user it.
+        if (Best.size() == 1) {
+          getDiagnostics().Report(Path[I].second, 
+                                  diag::err_no_submodule_suggest)
+            << Path[I].first << Sub->getFullModuleName() << Best[0]
+            << SourceRange(Path[0].second, Path[I-1].second)
+            << FixItHint::CreateReplacement(SourceRange(Path[I].second),
+                                            Best[0]);
+          Pos = Sub->SubModules.find(Best[0]);
+        }
+      }
+      
+      if (Pos == Sub->SubModules.end()) {
+        // No submodule by this name. Complain, and don't look for further
+        // submodules.
+        getDiagnostics().Report(Path[I].second, diag::err_no_submodule)
+          << Path[I].first << Sub->getFullModuleName()
+          << SourceRange(Path[0].second, Path[I-1].second);
+        break;
+      }
+      
+      Sub = Pos->getValue();
+    }
+  }
+  
+  // FIXME: Tell the AST reader to make the named submodule visible.
+  
+  // FIXME: The module file's FileEntry makes a poor key indeed! Once we 
+  // eliminate the need for FileEntry here, the module itself will become the
+  // key (which does make sense).
+  return Known.getOpaqueValue();
 }