Adds support for auto-detection of compilation databases

from a source file and changes clang-check to make use of this.

This makes clang-check just work on in-tree builds, and allows
easy setup via a symlink per source directory to make clang-check
work without any extra configuration.

llvm-svn: 159990

clang/include/clang/Tooling/CompilationDatabase.h

@@ -81,6 +81,13 @@ public:
   static CompilationDatabase *loadFromDirectory(StringRef BuildDirectory,
                                                 std::string &ErrorMessage);
 
+  /// \brief Tries to detect a compilation database location and load it.
+  ///
+  /// Looks for a compilation database in all parent paths by calling
+  /// loadFromDirectory.
+  static CompilationDatabase *autoDetectFromSource(StringRef SourceFile,
+                                                   std::string &ErrorMessage);
+
   /// \brief Returns all compile commands in which the specified file was
   /// compiled.
   ///
@@ -215,4 +222,3 @@ private:
 } // end namespace clang
 
 #endif // LLVM_CLANG_TOOLING_COMPILATION_DATABASE_H
-

clang/include/clang/Tooling/Tooling.h

@@ -232,6 +232,22 @@ FrontendActionFactory *newFrontendActionFactory(FactoryT *ConsumerFactory) {
   return new FrontendActionFactoryAdapter(ConsumerFactory);
 }
 
+/// \brief Returns the absolute path of \c File, by prepending it with
+/// the current directory if \c File is not absolute.
+///
+/// Otherwise returns \c File.
+/// If 'File' starts with "./", the returned path will not contain the "./".
+/// Otherwise, the returned path will contain the literal path-concatenation of
+/// the current directory and \c File.
+///
+/// The difference to llvm::sys::fs::make_absolute is that we prefer
+/// ::getenv("PWD") if available.
+/// FIXME: Make this functionality available from llvm::sys::fs and delete
+///        this function.
+///
+/// \param File Either an absolute or relative path.
+std::string getAbsolutePath(StringRef File);
+
 } // end namespace tooling
 } // end namespace clang
 

clang/lib/Tooling/CompilationDatabase.cpp

@@ -12,6 +12,7 @@
 //===----------------------------------------------------------------------===//
 
 #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"
@@ -121,6 +122,23 @@ CompilationDatabase::loadFromDirectory(StringRef BuildDirectory,
   return Database.take();
 }
 
+CompilationDatabase *
+CompilationDatabase::autoDetectFromSource(StringRef SourceFile,
+                                          std::string &ErrorMessage) {
+  llvm::SmallString<1024> AbsolutePath(getAbsolutePath(SourceFile));
+  StringRef Directory = llvm::sys::path::parent_path(AbsolutePath);
+  while (!Directory.empty()) {
+    std::string LoadErrorMessage;
+    if (CompilationDatabase *DB = loadFromDirectory(Directory,
+                                                    LoadErrorMessage))
+      return DB;
+    Directory = llvm::sys::path::parent_path(Directory);
+  }
+  ErrorMessage = ("Could not auto-detect compilation database for file \"" +
+                  SourceFile + "\"").str();
+  return NULL;
+}
+
 FixedCompilationDatabase *
 FixedCompilationDatabase::loadFromCommandLine(int &Argc,
                                               const char **Argv,
@@ -283,4 +301,3 @@ bool JSONCompilationDatabase::parse(std::string &ErrorMessage) {
 
 } // end namespace tooling
 } // end namespace clang
-

clang/lib/Tooling/Tooling.cpp

@@ -115,20 +115,13 @@ bool runToolOnCode(clang::FrontendAction *ToolAction, const Twine &Code,
   return Invocation.run();
 }
 
-/// \brief Returns the absolute path of 'File', by prepending it with
-/// 'BaseDirectory' if 'File' is not absolute.
-///
-/// Otherwise returns 'File'.
-/// If 'File' starts with "./", the returned path will not contain the "./".
-/// Otherwise, the returned path will contain the literal path-concatenation of
-/// 'BaseDirectory' and 'File'.
-///
-/// \param File Either an absolute or relative path.
-/// \param BaseDirectory An absolute path.
-static std::string getAbsolutePath(
-    StringRef File, StringRef BaseDirectory) {
+std::string getAbsolutePath(StringRef File) {
+  llvm::SmallString<1024> BaseDirectory;
+  if (const char *PWD = ::getenv("PWD"))
+    BaseDirectory = PWD;
+  else
+    llvm::sys::fs::current_path(BaseDirectory);
   SmallString<1024> PathStorage;
-  assert(llvm::sys::path::is_absolute(BaseDirectory));
   if (llvm::sys::path::is_absolute(File)) {
     llvm::sys::path::native(File, PathStorage);
     return PathStorage.str();
@@ -240,14 +233,8 @@ ClangTool::ClangTool(const CompilationDatabase &Compilations,
                      ArrayRef<std::string> SourcePaths)
     : Files((FileSystemOptions())),
       ArgsAdjuster(new ClangSyntaxOnlyAdjuster()) {
-  llvm::SmallString<1024> BaseDirectory;
-  if (const char *PWD = ::getenv("PWD"))
-    BaseDirectory = PWD;
-  else
-    llvm::sys::fs::current_path(BaseDirectory);
   for (unsigned I = 0, E = SourcePaths.size(); I != E; ++I) {
-    llvm::SmallString<1024> File(getAbsolutePath(
-        SourcePaths[I], BaseDirectory));
+    llvm::SmallString<1024> File(getAbsolutePath(SourcePaths[I]));
 
     std::vector<CompileCommand> CompileCommandsForFile =
       Compilations.getCompileCommands(File.str());

clang/test/Tooling/auto-detect-from-source-parent-of-cwd.cpp

@@ -0,0 +1,8 @@
+// RUN: rm -rf %t
+// RUN: mkdir -p %t/abc/def/ijk/qwe
+// RUN: echo "[{\"directory\":\".\",\"command\":\"clang++ -c %t/abc/def/ijk/qwe/test.cpp\",\"file\":\"%t/abc/def/ijk/qwe/test.cpp\"}]" | sed -e 's/\\/\\\\/g' > %t/compile_commands.json
+// RUN: cp "%s" "%t/abc/def/ijk/qwe/test.cpp"
+// RUN: PWD="%t/abc/def" clang-check "ijk/qwe/test.cpp" 2>&1 | FileCheck %s
+
+// CHECK: C++ requires
+invalid;

clang/test/Tooling/auto-detect-from-source-parent.cpp

@@ -0,0 +1,8 @@
+// RUN: rm -rf %t
+// RUN: mkdir -p %t/abc/def/ijk/qwe
+// RUN: echo "[{\"directory\":\".\",\"command\":\"clang++ -c %t/abc/def/ijk/qwe/test.cpp\",\"file\":\"%t/abc/def/ijk/qwe/test.cpp\"}]" | sed -e 's/\\/\\\\/g' > %t/compile_commands.json
+// RUN: cp "%s" "%t/abc/def/ijk/qwe/test.cpp"
+// RUN: clang-check "%t/abc/def/ijk/qwe/test.cpp" 2>&1 | FileCheck %s
+
+// CHECK: C++ requires
+invalid;

clang/test/Tooling/auto-detect-from-source.cpp

@@ -0,0 +1,8 @@
+// RUN: rm -rf %t
+// RUN: mkdir %t
+// RUN: echo "[{\"directory\":\".\",\"command\":\"clang++ -c %t/test.cpp\",\"file\":\"%t/test.cpp\"}]" | sed -e 's/\\/\\\\/g' > %t/compile_commands.json
+// RUN: cp "%s" "%t/test.cpp"
+// RUN: clang-check "%t/test.cpp" 2>&1 | FileCheck %s
+
+// CHECK: C++ requires
+invalid;

clang/test/Tooling/clang-check-args.cpp

@@ -1,4 +1,4 @@
-// RUN: clang-check . "%s" -- -c 2>&1 | FileCheck %s
+// RUN: clang-check "%s" -- -c 2>&1 | FileCheck %s
 
 // CHECK: C++ requires
 invalid;

clang/test/Tooling/clang-check-builtin-headers.cpp

@@ -3,7 +3,7 @@
 // Add a path that doesn't exist as argv[0] for the compile command line:
 // RUN: echo '[{"directory":".","command":"/random/tool -c %t/test.cpp","file":"%t/test.cpp"}]' | sed -e 's/\\/\//g' > %t/compile_commands.json
 // RUN: cp "%s" "%t/test.cpp"
-// RUN: clang-check "%t" "%t/test.cpp" 2>&1|FileCheck %s
+// RUN: clang-check -p "%t" "%t/test.cpp" 2>&1|FileCheck %s
 // FIXME: Make the above easier.
 
 #include <stddef.h>

clang/test/Tooling/clang-check-chdir.cpp

@@ -5,7 +5,7 @@
 // RUN: echo "[{\"directory\":\"%t\",\"command\":\"clang -c test.cpp -I.\",\"file\":\"%t/test.cpp\"}]" | sed -e 's/\\/\//g' > %t/compile_commands.json
 // RUN: cp "%s" "%t/test.cpp"
 // RUN: touch "%t/clang-check-test.h"
-// RUN: clang-check "%t" "%t/test.cpp" 2>&1|FileCheck %s
+// RUN: clang-check -p "%t" "%t/test.cpp" 2>&1|FileCheck %s
 // FIXME: Make the above easier.
 
 #include "clang-check-test.h"

clang/test/Tooling/clang-check-pwd.cpp

@@ -2,7 +2,7 @@
 // RUN: mkdir %t
 // RUN: echo "[{\"directory\":\".\",\"command\":\"clang++ -c %t/test.cpp\",\"file\":\"%t/test.cpp\"}]" | sed -e 's/\\/\\\\/g' > %t/compile_commands.json
 // RUN: cp "%s" "%t/test.cpp"
-// RUN: PWD="%t" clang-check "%t" "test.cpp" 2>&1|FileCheck %s
+// RUN: PWD="%t" clang-check -p "%t" "test.cpp" 2>&1|FileCheck %s
 // FIXME: Make the above easier.
 
 // CHECK: C++ requires

clang/test/Tooling/clang-check.cpp

@@ -2,7 +2,7 @@
 // RUN: mkdir %t
 // RUN: echo '[{"directory":".","command":"clang++ -c %t/test.cpp","file":"%t/test.cpp"}]' | sed -e 's/\\/\//g' > %t/compile_commands.json
 // RUN: cp "%s" "%t/test.cpp"
-// RUN: clang-check "%t" "%t/test.cpp" 2>&1|FileCheck %s
+// RUN: clang-check -p "%t" "%t/test.cpp" 2>&1|FileCheck %s
 // FIXME: Make the above easier.
 
 // CHECK: C++ requires

clang/test/Tooling/multi-jobs.cpp

@@ -1,4 +1,4 @@
-// RUN: clang-check . "%s" -- -no-integrated-as -c 2>&1 | FileCheck %s
+// RUN: clang-check "%s" -- -no-integrated-as -c 2>&1 | FileCheck %s
 
 // CHECK: C++ requires
 invalid;

clang/tools/clang-check/ClangCheck.cpp

@@ -42,8 +42,9 @@ using namespace clang::tooling;
 using namespace llvm;
 
 cl::opt<std::string> BuildPath(
-  cl::Positional,
-  cl::desc("<build-path>"));
+  "p",
+  cl::desc("<build-path>"),
+  cl::Optional);
 
 cl::list<std::string> SourcePaths(
   cl::Positional,
@@ -56,8 +57,13 @@ int main(int argc, const char **argv) {
   cl::ParseCommandLineOptions(argc, argv);
   if (!Compilations) {
     std::string ErrorMessage;
+    if (!BuildPath.empty()) {
       Compilations.reset(CompilationDatabase::loadFromDirectory(BuildPath,
                                                                 ErrorMessage));
+    } else {
+      Compilations.reset(CompilationDatabase::autoDetectFromSource(
+          SourcePaths[0], ErrorMessage));
+    }
     if (!Compilations)
       llvm::report_fatal_error(ErrorMessage);
   }