Hooks for custom CompilationDatabase

[djasper]

Summary

Add a hook to supply a custom CompilationDatabase. To add a custom CompilationDatabase, make it implement findCompilationDatabaseForDirectory in CustomCompilationDatabase.h and set USE_COSTUM_COMPILATION_DATABASE.

[klimek]

Do we want to add a FIXME comment about where we want this to go in the future, so others can jump in and run ahead easily? The CustomCompilationDatabase.h header comment would seem like the perfect place.

For example:
The mechanism can be used by IDEs or non-public code bases to integrate with their build system. Currently we support statically linking in an implementation of \c findCompilationDatabaseForDirectory and enabling it with -DUSE_CUSTOM_COMPILATION_DATABASE when compiling the Tooling library.

FIXME: The strategy forward is to provide a plugin system that can load custom compilation databases and make enabling that a build option.

lib/Tooling/CompilationDatabase.cpp

21

I think that's either spelled COSTUME or CUSTOM.

[djasper]

Modified comment according to suggestion and fixed spelling.

[chandlerc]

The code looks fine, but see my comment below...

lib/Tooling/CustomCompilationDatabase.h

32

What are the semantics of Directory? Which directory will be passed in? That of the file? The project? The working directory?

How will we even identify the project directory if we don't have the compilation database file?

I think there are some unanswered interface and design questions here.

[djasper]

Add comment explaining (a suggestion for) the interface.

[djasper]

Restrict interface to directories.

[djasper]

Typo..

lib/Tooling/CustomCompilationDatabase.h

32

I suggest this comment as interface definition. What do you think?

[chandlerc]

LGTM

[djasper]

Closed by commit rL160061 (authored by @djasper).

lib/Tooling/CompilationDatabase.cpp

 
 #include "clang/Tooling/CompilationDatabase.h"
 #include "clang/Tooling/Tooling.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/Support/YAMLParser.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/system_error.h"
 
+#ifdef USE_CUSTOM_COMPILATION_DATABASE
+#include "CustomCompilationDatabase.h"
+#endif
+
 namespace clang {
 namespace tooling {
 
 namespace {
 
 /// \brief A parser for escaped strings of command line arguments.
 ///
 /// Assumes \-escaping for quoted arguments (see the documentation of
CompilationDatabase::loadFromDirectory(StringRef BuildDirectory,
   if (!Database) {
     return NULL;
   }
   return Database.take();
 }
 
 static CompilationDatabase *
 findCompilationDatabaseFromDirectory(StringRef Directory) {
+#ifdef USE_CUSTOM_COMPILATION_DATABASE
+  if (CompilationDatabase *DB =
+      ::findCompilationDatabaseForDirectory(Directory))
+    return DB;
+#endif
   while (!Directory.empty()) {
     std::string LoadErrorMessage;
 
     if (CompilationDatabase *DB =
            CompilationDatabase::loadFromDirectory(Directory, LoadErrorMessage))
       return DB;
 
     Directory = llvm::sys::path::parent_path(Directory);

lib/Tooling/CustomCompilationDatabase.h

+//===--- CustomCompilationDatabase.h --------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+//  This file contains a hook to supply a custom \c CompilationDatabase
+//  implementation.
+//
+//  The mechanism can be used by IDEs or non-public code bases to integrate with
+//  their build system. Currently we support statically linking in an
+//  implementation of \c findCompilationDatabaseForDirectory and enabling it
+//  with -DUSE_CUSTOM_COMPILATION_DATABASE when compiling the Tooling library.
+//
+//  FIXME: The strategy forward is to provide a plugin system that can load
+//  custom compilation databases and make enabling that a build option.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ADT/StringRef.h"
+
+namespace clang {
+namespace tooling {
+class CompilationDatabase;
+}
+}
+
+/// \brief Returns a CompilationDatabase for the given \c Directory.
+///
+/// \c Directory can be any directory within a project. This methods will
+/// then try to find compilation database files in \c Directory or any of its
+/// parents. If a compilation database cannot be found or loaded, returns NULL.
+clang::tooling::CompilationDatabase *findCompilationDatabaseForDirectory(
+  llvm::StringRef Directory);