This is the next step in building the standalone tools infrastructure:

This patch simplifies writing of standalone Clang tools. As an
example, we add clang-check, a tool that runs a syntax only frontend
action over a .cc file. When you integrate this into your favorite
editor, you get much faster feedback on your compilation errors, thus
reducing your feedback cycle especially when writing new code.

The tool depends on integration of an outstanding patch to CMake to
work which allows you to always have a current compile command
database in your cmake output directory when you set
CMAKE_EXPORT_COMPILE_COMMANDS.

llvm-svn: 130306

1 files changed, 107 insertions, 0 deletions

diff --git a/clang/lib/Tooling/JsonCompileCommandLineDatabase.h b/clang/lib/Tooling/JsonCompileCommandLineDatabase.h
new file mode 100644
index 00000000000..dcd1e4bbbb5
--- /dev/null
+++ b/clang/lib/Tooling/JsonCompileCommandLineDatabase.h
@@ -0,0 +1,107 @@
+//===--- JsonCompileCommandLineDatabase - Simple JSON database --*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+//  This file implements reading a compile command line database, as written
+//  out for example by CMake. It only supports the subset of the JSON standard
+//  that is needed to parse the CMake output.
+//  See http://www.json.org/ for the full standard.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLING_JSON_COMPILE_COMMAND_LINE_DATABASE_H
+#define LLVM_CLANG_TOOLING_JSON_COMPILE_COMMAND_LINE_DATABASE_H
+
+#include "llvm/ADT/StringRef.h"
+#include <string>
+#include <vector>
+
+namespace clang {
+namespace tooling {
+
+/// \brief Converts a JSON escaped command line to a vector of arguments.
+///
+/// \param JsonEscapedCommandLine The escaped command line as a string. This
+/// is assumed to be escaped as a JSON string (e.g. " and \ are escaped).
+/// In addition, any arguments containing spaces are assumed to be \-escaped
+///
+/// For example, the input (|| denoting non C-escaped strings):
+///   |./call  a  \"b \\\" c \\\\ \"  d|
+/// would yield:
+///   [ |./call|, |a|, |b " c \ |, |d| ].
+std::vector<std::string> UnescapeJsonCommandLine(
+    llvm::StringRef JsonEscapedCommandLine);
+
+/// \brief Interface for users of the JsonCompileCommandLineParser.
+class CompileCommandHandler {
+ public:
+  virtual ~CompileCommandHandler() {};
+
+  /// \brief Called after all translation units are parsed.
+  virtual void EndTranslationUnits() {}
+
+  /// \brief Called at the end of a single translation unit.
+  virtual void EndTranslationUnit() {}
+
+  /// \brief Called for every (Key, Value) pair in a translation unit
+  /// description.
+  virtual void HandleKeyValue(llvm::StringRef Key, llvm::StringRef Value) {}
+};
+
+/// \brief A JSON parser that supports the subset of JSON needed to parse
+/// JSON compile command line databases as written out by CMake.
+///
+/// The supported subset describes a list of compile command lines for
+/// each processed translation unit. The translation units are stored in a
+/// JSON array, where each translation unit is described by a JSON object
+/// containing (Key, Value) pairs for the working directory the compile command
+/// line was executed from, the main C/C++ input file of the translation unit
+/// and the actual compile command line, for example:
+/// [
+///   {
+///     "file":"/file.cpp",
+///     "directory":"/",
+///     "command":"/cc /file.cpp"
+///   }
+/// ]
+class JsonCompileCommandLineParser {
+ public:
+  /// \brief Create a parser on 'Input', calling 'CommandHandler' to handle the
+  /// parsed constructs. 'CommandHandler' may be NULL in order to just check
+  /// the validity of 'Input'.
+  JsonCompileCommandLineParser(const llvm::StringRef Input,
+                               CompileCommandHandler *CommandHandler);
+
+  /// \brief Parses the specified input. Returns true if no parsing errors were
+  /// foudn.
+  bool Parse();
+
+  /// \brief Returns an error message if Parse() returned false previously.
+  std::string GetErrorMessage() const;
+
+ private:
+  bool ParseTranslationUnits();
+  bool ParseTranslationUnit(bool First);
+  bool ParseObjectKeyValuePairs();
+  bool ParseString(llvm::StringRef &String);
+  bool Consume(char C);
+  bool ConsumeOrError(char C, llvm::StringRef Message);
+  void NextNonWhitespace();
+  bool IsWhitespace();
+  void SetExpectError(char C, llvm::StringRef Message);
+
+  const llvm::StringRef Input;
+  llvm::StringRef::iterator Position;
+  std::string ErrorMessage;
+  CompileCommandHandler * const CommandHandler;
+};
+
+} // end namespace tooling
+} // end namespace clang
+
+#endif // LLVM_CLANG_TOOLING_JSON_COMPILE_COMMAND_LINE_DATABASE_H